JP6981225B2 - Gear manufacturing method - Google Patents

Description

The present invention relates to a method of manufacturing a tooth wheel.

Gears are mechanical elements that can transmit power by changing the direction and speed of power, and are used in various fields such as precision equipment, mechanical equipment, and automobiles. When strength is particularly required, metal gears are used.
Metal gears are stronger but heavier than resin gears. Therefore, for example, in the case of spur gears, the wall thickness from the tooth portion composed of a plurality of teeth to the shaft hole portion is not constant, but a disk-shaped web whose wall thickness is thinner than the tooth width of the tooth portion. By adopting a structure including a portion, it is possible to obtain a lightweight gear while having a predetermined strength. Further, in order to reduce the weight, a hole may be formed in the web portion (see Patent Document 1).

In the manufacture of gears, in general, a rough material with a constant wall thickness is first produced by forging, and after being heat-treated such as normalizing, the teeth and web parts are formed by cutting, and the finish is polished. (See Patent Document 2).

Japanese Unexamined Patent Publication No. 2015-59579 Japanese Unexamined Patent Publication No. 11-254081

As mentioned above, when the web part is processed from a rough material with a constant wall thickness to a thin wall by cutting, or when a hole is made, the amount of cutting is large, so the yield of the material is poor and it takes time to process. It takes.

Accordingly, the present invention aims to provide a manufacturing method of a gear with improved stay walking.

In the present invention, the hollow disk-shaped portion, the rim portion provided at the radially outer or inner end of the hollow disk-shaped portion, and the rim portion on the side opposite to the hollow disk-shaped portion side. A method for manufacturing a gear having a tooth portion provided on a surface, wherein a material for a gear is forged to form a disk-shaped portion or the hollow disk-shaped portion to be the hollow disk-shaped portion, and the hollow disk-shaped portion is formed. Forging step of forming the rim portion and the protruding portion to be the tooth portion by projecting to both sides in the plate thickness direction at the radial outer end of the disk-shaped portion or the radial inner end of the hollow disk-shaped portion. And the gear cutting step of forming the tooth portion by cutting the surface of the protruding portion on the side opposite to the side of the disk-shaped portion or the surface on the side opposite to the side of the hollow disk-shaped portion. , And after the forging step and before the gear cutting step, the protruding portion is deformed in the radial direction on both sides of the disk-shaped portion or the hollow disk-shaped portion in the axial direction. method of manufacturing a including tooth wheel bending step of forming the rim portion with two hollow frustoconical section about.

Further, in the present invention, the hollow disk-shaped portion, the rim portion provided at the radially outer or inner end of the hollow disk-shaped portion, and the rim portion opposite to the hollow disk-shaped portion side. A method for manufacturing a gear having a tooth portion provided on a side surface, wherein a material for gears is forged to form a disk-shaped portion or the hollow disk-shaped portion to be the hollow disk-shaped portion. , At the radially outer end of the disk-shaped portion or the radially inner end of the hollow disk-shaped portion, project to both sides in the plate thickness direction to form the rim portion and the protruding portion to be the tooth portion. Tooth cutting to form the tooth portion by cutting the surface of the protruding portion opposite to the side of the disk-shaped portion or the surface of the protruding portion opposite to the side of the hollow disk-shaped portion. The step is included, and after the forging step and before the gear cutting step, the protruding portion is cut so that the disc-shaped portion or the hollow disc-shaped portion is formed on both sides in the axial direction. One further method of manufacturing a including tooth wheel cutting step of forming the rim portion having a hollow truncated cone portion.

Further, the surface of the protruding portion formed in the forging step on the side of the disk-shaped portion or the side of the hollow disk-shaped portion is the side of the disk-shaped portion of the hollow truncated cone-shaped portion or the said. It constitutes a surface on the side of the hollow disk-shaped portion, and in the cutting process, the surface of the protruding portion on the side opposite to the disk-shaped portion or the surface opposite to the hollow disk-shaped portion is cut. It is preferable that the rim portion is formed.

Further, the material for the gear is preferably made of special steel or stainless steel.

Further, the material for gears is preferably formed by processing from a special steel plate or a stainless steel plate.

According to the gear of the present invention, the strength of the gear is maintained by setting the plate thickness of the hollow disk-shaped portion to a predetermined plate thickness, and the plate thickness of the hollow disk-shaped portion is configured to be thinner than that of the rim portion. Moreover, by making the surface of the hollow disk-shaped part of the rim part into the shape of the side surface of the truncated cone and providing the tooth part on the opposite side, the weight of the rim part can be reduced as compared with the conventional cylindrical rim part. Is. Further, according to the method for manufacturing a gear of the present invention, the hollow disk-shaped portion is formed to be thin by forging, and the rim portion and the protruding portion to be the tooth portion are formed, so that the tooth portion is formed with a small amount of cutting. It is possible to improve the yield of the material.

It is a schematic sectional drawing which shows the structure of the external gear in embodiment of this invention. It is a figure which shows the combination example of the external gear of FIG. It is a schematic sectional drawing which shows the structure of the internal gear in embodiment of this invention. It is a figure which shows the combination example of the external gear of FIG. 1 and the internal gear of FIG. It is explanatory drawing which shows the process of the 1st manufacturing method of the external gear and the internal gear of this invention. It is a figure which shows the material for a gear of this invention. It is a figure which shows the forging process of the external gear which concerns on the 1st manufacturing method of this invention. It is a figure which shows the bending process to the outside in the radial direction of the external gear which concerns on the 1st manufacturing method of this invention. It is a figure which shows the bending process inward in the radial direction of the external gear which concerns on the 1st manufacturing method of this invention. It is a figure which shows the forging process of the internal gear which concerns on the 1st manufacturing method of this invention. It is a figure which shows the bending process to the outside in the radial direction of the internal gear which concerns on the 1st manufacturing method of this invention. It is a figure which shows the bending process inward in the radial direction of the internal gear which concerns on the 1st manufacturing method of this invention. It is explanatory drawing which shows the process of the 2nd manufacturing method of the external gear and the internal gear of this invention. It is a figure which shows the forging process of the external gear which concerns on the 2nd manufacturing method of this invention. It is a figure which shows the cutting process of the external gear which concerns on the 2nd manufacturing method of this invention. It is a figure which shows the forging process of the internal gear which concerns on the 2nd manufacturing method of this invention. It is a figure which shows the cutting process of the internal gear which concerns on the 2nd manufacturing method of this invention. It is schematic cross-sectional view which shows the structure of the gear of the modification of the embodiment of this invention. It is explanatory drawing which shows the process of the manufacturing method of the gear which concerns on the modification of this invention.

Hereinafter, preferred embodiments of the gear and the method for manufacturing the gear of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of an external gear 100 as a gear according to the present embodiment, and FIG. 2 is a cross-sectional view of an internal gear 200 as a gear according to the present embodiment. FIG. 1A shows an external gear 100A having a valley-shaped tooth portion 130A, and FIG. 1B shows an external gear 100B having a mountain-shaped tooth portion 130B. FIG. 2A shows an internal gear 200A having a chevron shape of the tooth portion 230A, and FIG. 2B shows an internal gear 200B having a valley shape of the tooth portion 230B.
First, the configuration of the external gear 100 will be described in detail with reference to FIG.

As shown in FIG. 1A, the external gear 100A includes a hollow disk-shaped portion 110, a rim portion 120A, and a tooth portion 130A.

The hollow disk-shaped portion 110 has a predetermined plate thickness, and is composed of a disk-shaped plate having a shaft hole formed in the central portion. The plate thickness of the hollow disk-shaped portion 110 is thinner than the size of the rim portion 120A in the plate thickness direction.

The rim portion 120A is provided so as to project on both sides of the hollow disc-shaped portion 110 in the plate thickness direction at the radial outer end of the hollow disc-shaped portion 110. The rim portion 120A has two hollow truncated cone-shaped portions, and more specifically, in FIG. 1A, the first hollow truncated cone-shaped portion 121A is on the upper side and the second hollow is on the lower side. It is provided with a truncated cone-shaped portion 122A. The first hollow cone-shaped portion 121A and the second hollow cone-shaped portion 122A extend so that the angle θ1 formed with the hollow disc-shaped portion 110 is an obtuse angle. As a result, the radial outer surface of the rim portion 120A is formed in a valley shape.
The hollow cone trapezoidal portion refers to a portion formed in a truncated cone shape with a predetermined wall thickness and having a hollow inside. The same applies to the following description.

Further, the sandwiching angle θ2 between the first hollow cone-shaped portion 121A and the second hollow cone-shaped portion 122A on the outer side in the radial direction (hereinafter referred to as the sandwiching angle θ2 of the rim portion 120A) is the tooth portion 130A. It suffices to set the angle so that it can be formed, and it is possible to set it to 75 ° or more from the processing conditions at the time of manufacturing. In this embodiment, it is set to 90 °.
Further, since the inner surface of the rim portion 120A in the radial direction, that is, the surface on the hollow disk-shaped portion 110 side is formed so as to have a truncated cone side surface shape, the shape of the rim portion is compared with the cylindrical one. , The weight of the rim can be reduced.

The tooth portion 130A is provided on the radial outer surface of the rim portion 120A (the surface opposite to the hollow disk-shaped portion 110), and a plurality of teeth are formed on the tooth portion 130A. The tooth streaks of the tooth portion 130A may be parallel to or oblique to the axis.

In the present embodiment, the first hollow cone-shaped portion 121A and the second hollow cone-shaped portion 122A are configured to be symmetrical with respect to the hollow disk-shaped portion 110. Therefore, the rim portion 120A can evenly receive the load applied to the tooth portion 130A in the axial direction. The angle formed by the first hollow cone-shaped portion 121A and the second hollow cone-shaped portion 122A with the hollow disk-shaped portion 110 may be different from each other.

As shown in FIG. 1B, the external gear 100B includes a hollow disk-shaped portion 110, a rim portion 120B, and a tooth portion 130B. Since the configuration of the hollow disk-shaped portion 110 is the same as that described with respect to the external gear 100A, the description thereof will be omitted.

The rim portion 120B is provided so as to project on both sides of the hollow disc-shaped portion 110 in the plate thickness direction at the radial outer end of the hollow disc-shaped portion 110. The rim portion 120B has two hollow truncated cone-shaped portions, and more specifically, in FIG. 1B, a first hollow truncated cone-shaped portion 121B is on the upper side and a second hollow is on the lower side. It is provided with a truncated cone-shaped portion 122B. The first hollow cone-shaped portion 121B and the second hollow cone-shaped portion 122B extend so that the angle θ3 formed with the hollow disc-shaped portion 110 becomes an acute angle. As a result, the radial outer surface of the rim portion 120B is formed in a mountain shape.
Further, the angle formed by the first hollow cone-shaped portion 121B and the second hollow cone-shaped portion 122B (hereinafter referred to as the sandwiching angle of the rim portion 120B) on the inner side in the radial direction is 30 from the processing conditions at the time of manufacture. It can be greater than or equal to °. In this embodiment, it is set to 90 °.
Further, since the inner surface of the rim portion 120B in the radial direction, that is, the surface on the hollow disk-shaped portion 110 side is formed so as to have the shape of the side surface of the truncated cone, the shape of the rim portion is compared with the cylindrical one. , The weight of the rim can be reduced.

The tooth portion 130B is provided on the radial outer surface of the rim portion 120B (the surface opposite to the hollow disk-shaped portion 110), and a plurality of teeth are formed on the tooth portion 130B. The tooth streaks of the tooth portion 130B may be parallel to or oblique to the axis.

In the present embodiment, the first hollow cone-shaped portion 121B and the second hollow cone-shaped portion 122B are configured to be symmetrical with respect to the hollow disk-shaped portion 110. Therefore, the rim portion 120B can evenly receive the load applied to the tooth portion 130B in the axial direction. The angle formed by the first hollow cone-shaped portion 121B and the second hollow cone-shaped portion 122B with the hollow disk-shaped portion 110 may be different from each other.

In the external gear 100 described above, as shown in FIG. 2A, an external gear 100A having a predetermined diameter and an external gear 100B having a diameter smaller than the predetermined diameter are combined with their axes parallel to each other. Therefore, it can be used as a gear of a parallel axis. Further, as shown in FIG. 2B, by combining the axes of the plurality of external gears 100B in parallel, the gears can be used as parallel axis gears. Further, as shown in FIG. 2C, by crossing and combining the axes of the two external gears 100B, it can be used as a gear of the crossing shaft. Further, the external gear 100 of the present invention can also be used in combination with a conventional gear.

Next, the configuration of the internal gear 200 will be described in detail with reference to FIG.
As shown in FIG. 3A, the internal gear 200A includes a hollow disk-shaped portion 210, a rim portion 220A, and a tooth portion 230A.

The hollow disk-shaped portion 210 has a predetermined plate thickness, and is composed of a plate formed in an annular shape so that the rim portion 220A is arranged radially inside. The plate thickness of the hollow disk-shaped portion 210 is thinner than the size of the rim portion 220A in the plate thickness direction.

The rim portion 220A is provided so as to project on both sides of the hollow disc-shaped portion 210 in the plate thickness direction at the radially inner end portion of the hollow disc-shaped portion 210. The rim portion 220A has two hollow truncated cone-shaped portions, and more specifically, in FIG. 3A, the first hollow truncated cone-shaped portion 221A is on the upper side and the second hollow is on the lower side. It is provided with a truncated cone-shaped portion 222A. The first hollow cone-shaped portion 221A and the second hollow cone-shaped portion 222A extend so that the angle θ4 formed with the hollow disk-shaped portion 210 is an acute angle. As a result, the radial inner surface of the rim portion 220A is formed in a mountain shape.

Further, the angle formed by the first hollow cone-shaped portion 221A and the second hollow cone-shaped portion 222A on the outer side in the radial direction (hereinafter referred to as the sandwiching angle of the rim portion 220A) is 75 from the processing conditions at the time of manufacture. It can be greater than or equal to °. In this embodiment, it is set to 90 °.
Further, since the radial outer surface of the rim portion 220A, that is, the surface on the hollow disk-shaped portion 210 side is formed so as to have a truncated cone side surface shape, the shape of the rim portion is compared with the cylindrical one. , The weight of the rim can be reduced.

The tooth portion 230A is provided on the radial inner surface of the rim portion 220A (the surface opposite to the hollow disk-shaped portion 210), and a plurality of teeth are formed on the tooth portion 230A. The tooth streaks of the tooth portion 230A may be parallel to or oblique to the axis.

In the present embodiment, the first hollow cone-shaped portion 221A and the second hollow cone-shaped portion 222A are configured to be symmetrical with respect to the hollow disk-shaped portion 210. Therefore, the rim portion 220A can evenly receive the load applied to the tooth portion 230A in the axial direction. The angle formed by the first hollow cone-shaped portion 221A and the second hollow cone-shaped portion 222A with the hollow disk-shaped portion 210 may be different from each other.

As shown in FIG. 3B, the internal gear 200B includes a hollow disk-shaped portion 210, a rim portion 220B, and a tooth portion 230B. Since the configuration of the hollow disk-shaped portion 210 is the same as that described for the internal gear 200A, the description thereof will be omitted.

The rim portion 220B is provided so as to project on both sides of the hollow disc-shaped portion 210 in the plate thickness direction at the radially inner end portion of the hollow disc-shaped portion 210. The rim portion 220B has two hollow truncated cone-shaped portions, and more specifically, in FIG. 3B, a first hollow truncated cone-shaped portion 221B on the upper side and a second hollow on the lower side are shown. It is provided with a truncated cone-shaped portion 222B. The first hollow cone-shaped portion 221B and the second hollow cone-shaped portion 222B extend so that the angle θ5 formed by the hollow disc-shaped portion 210 is an obtuse angle. As a result, the inner surface of the rim portion 220B in the radial direction is formed in a valley shape.

Further, the sandwich angle θ6 between the first hollow cone trapezoidal portion 221B and the second hollow cone trapezoidal portion 222B (hereinafter referred to as the sandwich angle θ6 of the rim portion 220B) on the inner side in the radial direction is the tooth portion 230B. It suffices to set the angle so that it can be formed, and it is possible to set it to 30 ° or more from the processing conditions at the time of manufacturing. In this embodiment, it is set to 90 °.
Further, since the radial outer surface of the rim portion 220B, that is, the surface on the hollow disk-shaped portion 210 side is formed so as to have a truncated cone side surface shape, the shape of the rim portion is compared with the cylindrical one. , The weight of the rim can be reduced.

The tooth portion 230B is provided on the radial inner surface of the rim portion 220B (the surface opposite to the hollow disk-shaped portion 210), and a plurality of teeth are formed on the tooth portion 230B. The tooth streaks of the tooth portion 230B may be parallel to or oblique to the axis.

In the present embodiment, the first hollow cone-shaped portion 221B and the second hollow cone-shaped portion 222B are configured to be symmetrical with respect to the hollow disk-shaped portion 210. Therefore, the rim portion 220B can evenly receive the load applied to the tooth portion 230B in the axial direction. The angle formed by the first hollow cone-shaped portion 221B and the second hollow cone-shaped portion 222B with the hollow disk-shaped portion 210 may be different from each other.

As shown in FIG. 4A, in the internal gear 200 described above, the internal gear 200A having a predetermined diameter and the external gear 100A having a diameter smaller than the predetermined diameter are arranged in parallel with each other. By combining them, it can be used as a gear with a parallel axis. Similarly, as shown in FIG. 4B, a parallel shaft is formed by combining an internal gear 200B having a predetermined diameter and an external gear 100B having a diameter smaller than the predetermined diameter in parallel with each other. It can be used as a gear of. Further, as shown in FIG. 4C, by combining the internal gear 200B and the external gear 100B with their axes crossed, they can be used as gears with crossed shafts. Further, the internal gear 200 of the present embodiment can also be used in combination with the conventional external gear.

According to the gears 100 and 200 (external gears 100A and 100B, internal gears 200A and 200B) of the present embodiment described above, the following effects are obtained.

(1) The gear 100 (or 200) has a hollow disk-shaped portion 110 (or 210) having a predetermined plate thickness and a radial outside of the hollow disk-shaped portion 110 or a radial inside of the hollow disk-shaped portion 210. A rim portion that is provided so as to project on both sides of the hollow disk-shaped portion 110 (or 210) in the plate thickness direction at the end portion of the hollow disk-shaped portion 110 (or 210), and the surface on the hollow disk-shaped portion 110 (or 210) side has a truncated cone side surface shape. 120A, 120B (or 220A, 220B) and the tooth portions 130A, 130B (or 220B) provided on the surface of the rim portions 120A, 120B (or 220A, 220B) opposite to the hollow disk-shaped portion 110 (or 210). 230A, 230B) and so on. As a result, since the hollow disk-shaped portion 110 (or 210) has a predetermined plate thickness, the strength of the gear 100 (or 200) can be maintained, and the plate thickness of the hollow disk-shaped portion 110 (or 210) can be increased. The thickness is thinner than the rim portions 120A and 120B (or 220A and 220B) to reduce the weight, and the surface of the rim portion on the hollow disk-shaped portion side is shaped like a truncated cone to form a conventional cylindrical shape. Compared to the rim part, the rim part can be made lighter.

(2) Two hollow cones of rim portions 120A and 120B (or 220A and 220B) are provided on both sides in the plate thickness direction at the radial outer side of the hollow disc-shaped portion 110 or the inner end portion of the hollow disc-shaped portion 210. It was assumed to have trapezoidal portions 121A, 122A, 121B, 122B (or 221A, 222A, 221B, 222B). As a result, the rim portions 120A and 120B (or 220A and 220B) are configured to have a thin wall shape, so that the weight of the rim portion can be further reduced.

(3) The two hollow cone-shaped portions 121A and 122A, 121B and 122B (or 221A and 222A, 221B and 222B) are formed symmetrically with respect to the hollow disk-shaped portion 110 (or 210). As a result, the rim portion can receive the load applied to the tooth portion evenly in the axial direction, so that the strength of the gear 100 (or 200) can be increased.

Next, a first manufacturing method for manufacturing the gear of the present embodiment will be described with reference to FIGS. 5 to 10.
FIG. 5 shows an outline of the manufacturing process of the external gears 100A and 100B and the internal gears 200A and 200B in the first manufacturing method. As shown in FIG. 5, the manufacturing process goes through (1) blank processing process, (2) forging process, (3) bending process (4) gear cutting process and (5) drilling process, and if necessary. Perform the quenching process and finishing process.

Hereinafter, each step will be described in detail.
<Blank processing process>
From one raw material, a gear material 11 for an external gear and a gear material 21 for an internal gear are obtained by punching or wire electric discharge machining. As the raw material, special steel plates such as carbon steel for machine structure, tool steel, and bearing steel, steel plates made of stainless steel, and round bars that have been cut and installed into a disk shape can be used. Here, according to the manufacturing method of the present invention, the plate thicknesses of the gear materials 11 and 21 are not the same as the axial size of the rim portion, but the hollow disk-shaped portion 110 formed of a thin wall. It is necessary to use a plate that is close to the plate thickness of 210 and is slightly thick. Therefore, it is preferable to use a steel plate having a predetermined plate thickness rather than obtaining a thin disk-shaped raw material from a round bar material.
In this embodiment, gear materials 11 and 21 are obtained from one steel plate by wire electric discharge machining. By processing the gear materials 11 and 21 from the steel plate, the step of cutting the round bar and the step of setting up become unnecessary, and the manufacturing process can be simplified.
In the present embodiment, the gear material 11 for the external gear shown in FIG. 6A has, as an example, a disk-shaped shape having a thickness t = 4 mm and a diameter D = 24 mm, and is shown in FIG. 6B. The gear material 21 of the internal gear has a hollow disk-like shape having a thickness t = 4 mm, an outer diameter D = 48 mm, and an inner diameter d = 32 mm.

For each step after the forging step, the external gear 100 (100A, 100B) will be described first, and then the internal gear 200 (200A, 200B) will be described.
<Forging process (external gear)>
The forging process of the external gear 100 will be described with reference to FIG. 7.
A forging process is performed on the gear material 11 of the external gear obtained in the blank processing process.
As shown in FIG. 7, the diversion forging dies 1200 for external gears are arranged on the outer side in the radial direction with the upper die 1210 arranged at the upper part of the gear material 11 and the lower die 1220 arranged at the lower part. It is composed of a side mold 1230 to be formed. The gear material 11, the upper mold 1210, the lower mold 1220, and the side mold 1230 are arranged so that their central axes coincide with each other.
The upper mold 1210 has a cylindrical portion having a predetermined diameter (D = 18 mm) smaller than the outer diameter (D = 24 mm) of the gear material 11, and can be moved up and down.
The lower mold 1220 has a cylindrical portion having a predetermined diameter (D = 18 mm) that matches the upper mold 1210, which is smaller than the outer diameter of the gear material 11, and is fixed to the lower portion.
The side mold 1230 has an annular shape with an inner diameter (d = 24 mm) that matches the outer diameter of the gear material 11, and is fixed to the lower portion.

As shown in FIG. 7A, the gear material 11 is placed in the diversion forging die 1200 for external gears, and as shown in FIG. 7B, the upper die 1210 is pushed in by a predetermined amount. The forged body 12 shown in 7 (c) is formed.
The forged body 12 has a disc-shaped portion 110'having a predetermined diameter and a predetermined plate thickness to be a hollow disc-shaped portion 110, and protruding portions protruding from both sides in the axial direction on the outer circumference of the disc-shaped portion 110'. 120 and.
The plate thickness H3 of the disk-shaped portion 110'can be adjusted by the pushing amount H1 of the upper mold 1210, and can be calculated by subtracting the pushing amount H1 from the plate thickness t of the gear material 11 (FIG. FIG. 7 (c)).
The protrusion 120 has a predetermined size H2 in the axial direction, and is composed of a first protrusion 121 protruding upward and a second protrusion 122 protruding downward in FIG. 7 (c).

<Bending process (external gear)>
Next, the bending process of the external gear 100A will be described with reference to FIG. 8A.
As shown in FIG. 8A, the bending die 1300A for the external gear is composed of an upper die 1310A arranged at the upper part of the forged body 12 and a lower die 1321A and a lower die 1322A arranged at the lower part. It is composed.
The upper die 1310A has a truncated cone-shaped portion whose small diameter matches the diameter (D = 18 mm) of the upper die 1210 of the diversion forging die 1200 and whose generatrix forms a predetermined angle θ with respect to the central axis. It can be moved up and down.
The lower die 1321A has a cylindrical portion whose diameter matches the diameter (D = 18 mm) of the lower die 1220 of the diversion forging die 1200 and is fixed to the lower part.
The lower mold 1322A has a portion having the same shape as that of the upper mold 1310A inverted upside down, and is fixed to the lower portion.

The forged molded body 12 obtained in the forging step is arranged between the upper die 1310A and the lower die 1321A as shown in FIG. 8A (a), and the upper die is as shown in FIG. 8A (b). The forged body 12 is pressed by the die 1310A to deform the first protruding portion 121 radially outward to form the first hollow conical trapezoidal portion 121A. After that, the mold arranged at the lower part is replaced with the lower mold 1322A as shown in FIG. 8A (c), the forged compact 12 is turned upside down, and the upper mold 1310A is used as shown in FIG. 8A (d). The forged die 12 is pressurized to deform the second projecting portion 122 radially outward to form the second hollow cone trapezoidal portion 122A to obtain the rim portion forming body 13A. As described above, in the rim portion 120A composed of the first hollow cone trapezoidal portions 121A and 122A, the outer surface in the radial direction becomes valley-shaped due to the deformation of the extension flange in which the protrusion 120 extends in the outer diameter direction. It is formed. The upper mold 1310A and the lower mold 1322A may be used to simultaneously deform the first protruding portion 121 and the second protruding portion 122 in the radial direction.

Next, the bending process of the external gear 100B will be described with reference to FIG. 8B.
As shown in FIG. 8B, the bending die 1300B for the external gear includes an upper die 1310B arranged at the upper part of the forged body 12, a lower die 1321B, a lower die 1322B and a side surface arranged at the lower part. It is composed of a mold 1330.

The upper mold 1310B has a cylindrical shape having a diameter that matches the inner diameter of the side mold 1230 of the diversion forging die 1200, and has a shape portion in which a truncated cone having an upper side as an upper surface and a lower side as a bottom surface is hollowed out and the cone. It has a cylindrical part that is placed in the hollowed out part of the table, and can move up and down. The diameter of the bottom surface of the hollowed-out cone coincides with the inner diameter (d = 24 mm) of the side mold 1230 of the diversion forging die 1200, and the generatrix of the truncated cone forms a predetermined angle θ with respect to the central axis. Further, the diameter of the upper surface of the hollowed cone is smaller than the diameter of the cylindrical shape of the upper die 1210 of the diversion forging die 1200. Further, the diameter of the cylindrical shape arranged in the hollowed out portion of the truncated cone is smaller than the diameter of the upper surface of the hollowed out truncated cone. This cylindrical portion is arranged to restrain the radial deformation of the first protrusion 121 and the second protrusion 122.

The lower die 1321B has an upper cylindrical portion having a diameter matching the diameter of the lower die 1220 of the diversion forging die 1200 and a side die 1230 of the diversion forging die 1200 arranged below the upper cylindrical portion. It comprises a lower cylindrical portion having a diameter that matches the inner diameter of the, and is secured to the lower part. The upper cylindrical portion constrains the inner diameter side surfaces of the disc-shaped portion 110'and the second protruding portion 122, and the lower cylindrical portion supports the axial lower end of the second protruding portion 122.
The lower mold 1322B has a shape similar to that of the upper mold 1310B inverted upside down, and is fixed to the lower portion.

The side die 1330 has the same shape as the side die 1230 of the diversion forging die 1200, and is fixed to the lower portion. The side mold 1330 constrains the radial outside of the protrusion 120.

The forged molded body 12 obtained in the forging step is arranged between the upper die 1310B and the lower die 1321B as shown in FIG. 8B (a), and the upper die is as shown in FIG. 8B (b). The forged body 12 is pressed by 1310B to deform the first protruding portion 121 inward in the radial direction to form the first hollow conical trapezoidal portion 121B. After that, the mold arranged at the lower part is replaced with the lower mold 1322B as shown in FIG. 8B (c), the forged compact 12 is turned upside down, and the upper mold 1310B is used as shown in FIG. 8B (d). The forged die 12 is pressurized to deform the second projecting portion 122 inward in the radial direction to form the second hollow cone trapezoidal portion 122B to obtain the rim portion forming body 13B. In this way, the rim portion 120B composed of the first hollow cone trapezoidal portions 121B and 122B is formed so that the outer surface in the radial direction becomes a mountain shape due to the shrinkage flange deformation in which the protrusion 120 shrinks in the inner diameter direction. Will be done.

<Tooth cutting process>
Tooth portions 130A and 130B composed of a plurality of teeth are formed on the radial outer surfaces of the rim portion forming bodies 13A and 13B obtained in the bending process by gear cutting using a hobbing machine, a rack machine or the like. ..

<Drilling process>
After the forging step or the bending process, the hollow disc-shaped portion 110 is formed by making a circular hole having a predetermined diameter in the central portion of the disc-shaped portion 110'constituting the forged molded body 12.

The external gears 100A and 100B are obtained through the blank processing step, the forging process, the bending process, the gear cutting process, and the drilling process described above. For the external gears 100A and 100B, those for which it is necessary to increase the hardness are quenched in the next step. Further, for the tooth portions 130A and 130B, those that need to be formed with higher accuracy are lightly subjected to finishing processes such as cutting, grinding and polishing.

Next, each step after the forging step of the internal gear 200 will be described.
<Forging process (internal gear)>
The forging process of the internal gear 200 will be described with reference to FIG. A forging process is performed on the gear material 21 of the internal gear obtained in the blank processing process.

As shown in FIG. 9, the diversion forging die 2200 for the internal gear penetrates the upper mold 2210 arranged at the upper part of the gear material 21 of the internal gear and the gear material 21 of the internal gear at the lower part. It is composed of a lower mold 2220 to be arranged and a side mold 2230 arranged at the lower portion on the outer peripheral side of the gear material 21 of the internal gear. The gear material 21, the upper mold 2210, the lower mold 2220, and the side mold 2230 of the internal gear are arranged so that their central axes coincide with each other.

The upper mold 2210 includes an upper annular portion 2211 and a lower annular portion 2212. The upper annular portion 2211 has a predetermined inner diameter (d = 38 mm) that is smaller than the outer diameter (D = 48 mm) of the gear material 21 of the internal gear and larger than the inner diameter of the gear material 21 of the internal gear. The lower annular portion 2212 has a predetermined inner diameter (d = 48 mm) that matches the outer diameter of the gear material 21 of the internal gear.

The lower mold 2220 has a cylindrical portion having a predetermined diameter (D = 32 mm) that matches the inner diameter (d = 32 mm) of the gear material 21 of the internal gear, and is fixed to the lower portion.

The side mold 2230 has an annular shape and is fixed to the lower portion. The side mold 2230 has a predetermined outer diameter (D = 48 mm) that matches the outer diameter of the gear material 21 of the internal gear, and has a predetermined inner diameter (d = 38 mm) that matches the inner diameter of the upper annular portion 2211. Have.

As shown in FIG. 9A, the gear material 21 of the internal gear is supported and arranged by the side mold 2230 in a state where the lower mold 2220 penetrates. As shown in FIG. 9B, the forged molded body 22 shown in FIG. 9C is formed by pushing the upper mold 2210 by a predetermined amount.
The forged body 22 includes a hollow disk-shaped portion 210 and protrusions 220 protruding on both sides in the axial direction on the inner circumference of the hollow disk-shaped portion 210.
The plate thickness H3 of the hollow disk-shaped portion 210 can be adjusted by the pushing amount H1 of the upper mold 2210, and can be calculated by subtracting the pushing amount H1 from the plate thickness t of the gear material 21 of the internal gear. Yes (see FIG. 9 (c)).
The protrusion 220 has a predetermined size H2 in the axial direction, and is composed of a first protrusion 221 that protrudes upward and a second protrusion 222 that protrudes downward.

<Bending process (internal gear)>
Next, the bending process of the internal gear 200A will be described with reference to FIG. 10A.
As shown in FIG. 10A, the bending die 2300A for the internal gear is arranged in the upper die 2310A arranged in the upper part of the forged body 22, the lower die 2321A arranged in the lower part, and the lower part. It is composed of a lower mold 2322A and a side mold 2330.

The upper die 2310A is arranged inside the annular portion 2311A having the same shape as the lower annular portion 2212 of the upper die 2210 of the diversion forging die 2200, and the lower side is the upper surface and the upper side. It is provided with a truncated cone-shaped portion 2312A having a bottom surface and can be moved up and down. The diameter of the bottom surface of the truncated cone-shaped portion 2312A matches the inner diameter of the annular portion 2311A, the diameter of the upper surface matches the diameter of the lower mold 2220 of the diversion forging mold 2200, and the generatrix of the truncated cone is on the central axis. On the other hand, a predetermined angle θ is formed.

The lower die 2321A has a cylindrical portion 2324A penetrating the forged body 22, and a ring-shaped portion that restrains the radial outer surfaces of the hollow disk-shaped portion 210 and the second protruding portion 222 of the forged body 22. It includes a 2325A and a lower cylindrical portion 2326A that supports the lower end of the protruding portion 220 and is fixed to the lower portion. The cylindrical portion 2324A constrains the inner surface of the protrusion 220 excluding the first protrusion 221 and the lower cylindrical portion 2326A supports the axial lower end of the second protrusion 122.
The lower mold 2322A has a shape similar to that of the upper mold 2310A inverted upside down, and is fixed to the lower portion.

The side die 2330 has an annular shape having an inner diameter that matches the inner diameter of the lower annular portion 2212 of the upper die 2210 of the diversion forging die 2200, and is fixed to the lower portion. The side mold 2330 restrains the radial outer end of the hollow disc-shaped portion 210.

The forged molded body 22 obtained in the forging step is arranged between the upper die 2310A and the lower die 2321A as shown in FIG. 10A (a), and the upper die is as shown in FIG. 10A (b). The forged body 22 is pressed by the die 2310A to deform the first protruding portion 221 radially outward to form the first hollow conical trapezoidal portion 221A. After that, the mold arranged at the lower part is replaced with the lower mold 2322A as shown in FIG. 10A (c), the forged molded body 22 is turned upside down, and the upper mold 2310A is used as shown in FIG. 10A (d). The forged die 22 is pressurized to deform the second projecting portion 222 in the radial direction to form the second hollow cone trapezoidal portion 222A to obtain the rim portion forming body 23A. As described above, the rim portion 220A including the first hollow cone-shaped portion 221A and the second hollow cone trapezoidal portion 222A has the rim portion 220A due to the extension flange deformation in which the protrusion 220 extends in the outer diameter direction. The inner surface in the radial direction is formed in a chevron shape.

Next, the bending process of the internal gear 200B will be described with reference to FIG. 10B.
As shown in FIG. 10B, the bending die 2300B for the internal gear is arranged in the upper die 2310B arranged in the upper part of the forged body 22, the lower die 2321B arranged in the lower part, and the lower part. It is composed of a lower mold 2322B.

The upper mold 2310B has a hollowed-out portion of a truncated cone having an upper surface as an upper surface and a lower surface as a bottom surface, and can be moved up and down. The diameter of the hollowed out bottom surface coincides with the inner diameter of the upper annular portion 2211 of the upper die 2210 of the diversion forging die 2200, and the generatrix of the truncated cone forms a predetermined angle θ with respect to the central axis.
The lower die 2321B has an annular shape portion whose diameter matches the inner diameter (d = 38 mm) of the side mold 2230 of the diversion forging die 2200, and is fixed to the lower portion.
The lower mold 2322B has a shape similar to that of the upper mold 2310B inverted upside down, and is fixed to the lower portion.

The forged molded body 22 obtained in the forging step is arranged between the upper die 2310B and the lower die 2321B as shown in FIG. 10B (a), and the upper die is as shown in FIG. 10B (b). The forged body 22 is pressed by the die 2310B to deform the first protruding portion 221 inward in the radial direction to form the first hollow conical trapezoidal portion 221B. After that, the mold arranged at the lower part is replaced with the lower mold 2322B as shown in FIG. 10B (c), the forged molded body 22 is turned upside down, and the upper mold 2310B is used as shown in FIG. 10B (d). The forged die 22 is pressurized to deform the second projecting portion 222 inward in the radial direction to form the second hollow cone trapezoidal portion 222B to obtain the rim portion forming body 23B. As described above, the rim portion 220B including the first hollow cone-shaped portion 221B and the second hollow cone-shaped portion 222B has the rim portion 220B among the rim portions 220B due to the shrinkage flange deformation in which the protrusion 220 shrinks in the inner diameter direction. The inner surface in the radial direction is formed in a valley shape. The upper mold 2310B and the lower mold 2322B may be used to simultaneously deform the first protruding portion 221 and the second protruding portion 222 in the radial direction.

<Tooth cutting process>
Tooth portions 230A and 230B composed of a plurality of teeth are formed on the radial inner surfaces of the rim portion forming bodies 23A and 23B obtained in the bending step by gear cutting using a pinion cutter or the like.

The internal gear 200 is obtained through the blank processing step, the forging process, the bending process, and the gear cutting process described above. The internal gear 200 whose hardness needs to be increased is quenched in the next step. Further, for the tooth portions 230A and 230B, those that need to be formed with higher accuracy are lightly subjected to finishing processes such as cutting, grinding and polishing.

According to the first manufacturing method of the external gear 100 and the internal gear 200 of the present invention described above, the following effects are obtained.

(4) In the method of manufacturing the gear 100 (or 200), the material 11 (or 21) for gears is forged to form a disk-shaped portion 110'or a hollow disk-shaped portion 210 to be a hollow disk-shaped portion 110. At the same time, the rim portions 120A, 120B (or 220A, 220B) and the rim portions 120A, 120B (or 220A, 220B) protruding to both sides in the plate thickness direction at the radial outer end of the disc-shaped portion 110'or the radial inner end of the hollow disc-shaped portion 210. The forging step of forming the protruding portion 120 (or 220) to be the tooth portions 130A, 130B (or 230A, 230B), and the surface of the protruding portion 120 (or 220) opposite to the disk-shaped portion 110'side or It includes a gear cutting step of cutting a surface opposite to the hollow disk-shaped portion 210 to form tooth portions 130A, 130B (or 230A, 230B). As a result, the surface of the rim portions 120A and 120B (or 220A and 220B) opposite to the side on which the tooth portions 130A and 130B (or 230A and 230B) are provided is formed in the radial direction without cutting. Can be done. Further, the hollow disk-shaped portion 110 (or 210) can be formed thinly without cutting. Therefore, compared to the case where the hollow disk-shaped portion and the rim portion are all formed by cutting without forging, the manufacturing time can be shortened and the cutting amount can be reduced, so that the decrease in tool life can be suppressed and the material yield can be reduced. Can be improved.

(5) In the method of manufacturing a gear, the protruding portion 120 (or 220) is radially deformed after the forging step and before the gear cutting step, and the disc-shaped portion 110'or the hollow disc-shaped portion is formed. It includes a bending step of forming rims 120A, 120B (or 220A, 220B) having two hollow truncated cones on each side of 210 in the axial direction. Thereby, the rim portions 120A and 120B (or 220A and 220B) can be formed without cutting. Therefore, the manufacturing time can be shortened and the cutting amount can be reduced, so that it is possible to suppress a decrease in tool life and further improve the material yield.

(6) The material 11 (or 21) for gears is made of special steel or stainless steel. Even when the high-strength gear 100 (or 200) is manufactured using special steel or stainless steel, it can be manufactured with a small manufacturing load.

Next, a second manufacturing method for manufacturing the external gear 100 and the internal gear 200 of the present embodiment will be described with reference to FIGS. 11 to 15.

FIG. 11 shows an outline of the manufacturing process of the external gear 100A and the internal gear 200B in the second manufacturing method. As shown in FIG. 11, the manufacturing process goes through (1) blank processing process, (2) forging process, (3) cutting process, (4) gear cutting process and (5) drilling process, and if necessary. Perform the quenching process and finishing process. Since the (1) blank processing process, (4) gear cutting process and (5) drilling process are the same as those in the first manufacturing method, the description is omitted, and (2) forging process and (3) cutting process are omitted. Will be described in detail below.

<Forging process (external gear)>
The forging process of the external gear 100A will be described with reference to FIG. A forging process is performed on the gear material 11 obtained in the blank processing process.

As shown in FIG. 12, the diversion forging die 1200'for the external gear has an upper die 1210'arranged in the upper part of the gear material 11 for the external gear and a lower die 1220'arranged in the lower part. And a side mold 1230'arranged on the outer side in the radial direction. The gear material 11, the upper mold 1210', the lower mold 1220', and the side mold 1230' are arranged so that their central axes coincide with each other.

The upper mold 1210'has an inverted truncated cone-shaped portion 1211' with the upper surface facing the gear material 11 side and a cylindrical shape (disk shape) arranged on the upper portion (bottom side) of the inverted truncated cone-shaped portion 1211'. ) Part 1212'and can be moved up and down. In the inverted cone-shaped portion 1211', the generatrix forms a predetermined angle θ with respect to the central axis, and coincides with the upper surface having a predetermined diameter (D = 18 mm) and the outer diameter (D = 24 mm) of the gear material 11. It has a bottom surface with a diameter. The cylindrical portion 1212'has a diameter that matches the outer diameter (D = 24 mm) of the gear material 11.

The lower mold 1220'has a shape similar to that of the upper mold 1210' inverted upside down, and is fixed to the lower part.
The side mold 1230'has an annular shape with an inner diameter (d = 24 mm) that matches the outer diameter of the gear material 11, and is fixed to the lower portion.

By arranging the gear material 11 in the diversion forging die 1200'for the external gear as shown in FIG. 12 (a) and pushing the upper die 1210' by a predetermined amount as shown in FIG. 12 (b). , The forged body 12'shown in FIG. 12 (c) is formed.
The forged body 12'has a disc-shaped portion 110' having a predetermined diameter and a predetermined plate thickness to be a hollow disc-shaped portion 110, and protrusions protruding from both sides in the axial direction on the outer circumference of the disc-shaped portion 110'. A unit 120'is provided.
The plate thickness H3 of the disk-shaped portion 110'can be adjusted by the pushing amount H1 of the upper mold 1210', and can be calculated by subtracting the pushing amount H1 from the plate thickness t of the gear material 11 ( See FIG. 12 (c)).
The protrusion 120'is formed so that the cross-sectional shape cut at the surface including the shaft is triangular, and has a predetermined size H2 in the axial direction. Further, the radial inner surface of the protruding portion 120'(the surface on the disc-shaped portion 110' side) is formed on the radial inner surface of the rim portion 120A only by the forging process, regardless of the cutting process described later. Configure.

<Cutting process (external gear)>
Next, the cutting process of the external gear 100A will be described with reference to FIG. In the second manufacturing method, the radial outer surface of the protruding portion 120'(see FIG. 13 (a)) formed by the forging step is cut to form both sides of the disc-shaped portion 110'in the axial direction. A first hollow cone-shaped portion 121A and a second hollow cone-shaped portion 122A are formed in the rim portion 120A to obtain a rim portion forming body 13A. As shown in FIG. 13B, the rim portion 120A is formed so that the outer surface in the radial direction has a valley shape.

In the forging process of the second manufacturing method, the protruding portion is formed using the same die as the mold used in the forging step of the first manufacturing method, and then the entire surface of the protruding portion is cut in the cutting step. Thereby, the rim portion 120A may be formed. However, as described above, it is preferable to form one side of the rim portion 120A in the forging step and to form the other side by cutting in the cutting step to obtain the rim portion 120A because the cutting amount can be reduced.

The external gear 100A is obtained through the blanking process, the forging process, the cutting process, the gear cutting process, and the drilling process described above. The external gear 100A whose hardness needs to be increased is quenched in the next step. Further, for the tooth portion 130A that needs to be formed with higher accuracy, a finishing process such as cutting, grinding and polishing is performed lightly.

Next, the (2) forging process and (3) cutting process of the internal gear 200B in the second manufacturing method will be described in detail below.
<Forging process (internal gear)>
The forging process of the internal gear 200B will be described with reference to FIG. A forging process is performed on the gear material 21 for internal gears obtained in the blank processing process.

As shown in FIG. 14, the diversion forging die 2200'for the internal gear has an upper die 2210'arranged on the upper part of the gear material 21 so as to penetrate the gear material 21 and the gear material 21. It is composed of a lower mold 2220'arranged in the lower portion on the outer peripheral side and a side mold 2230'arranged on the outer side in the radial direction. The gear material 21, the upper mold 2210', the lower mold 2220', and the side mold 2230' are arranged so that their central axes coincide with each other.

The upper mold 2210'is provided with a cylindrical portion 2211'that penetrates the gear material 21 and an annular portion 2212' that is arranged at the upper part on the outer peripheral side of the gear material 21 and can be moved up and down. be. The cylindrical portion 2211'has a predetermined diameter (D = 32 mm) that matches the inner diameter (d = 32 mm) of the gear material 21. The annular shape portion 2212'is a small diameter portion having a shape in which a truncated cone having an upper side as an upper surface and a lower side as a bottom surface is hollowed out from a cylinder having a diameter matching the outer diameter (D = 48 mm) of the gear material 21. , It is arranged above this small diameter portion and has a large diameter portion having a larger diameter than the small diameter portion. The diameter of the bottom surface of the hollowed-out truncated cone matches the inner diameter of the hollow disk-shaped portion 210 of the internal gear 200B, and the diameter of the upper surface matches the inner diameter of the gear material 21 (d = 32 mm). The bus forms a predetermined angle θ with respect to the central axis.

The lower mold 2220'has an annular shape portion 2221' similar to the one in which the annular shape of the upper mold 2210'is inverted upside down at the lower portion of the gear material 21, and the lower portion of the annular shape portion 2221'. The cylindrical portion 2211'of the upper mold 2210'can penetrate, and is provided with an annular shaped portion 2222' having an outer diameter and an inner diameter that match the outer and inner diameters of the gear material 21 and is fixed to the lower part. To.
The side mold 2230'has an annular shape and is arranged on the side surface of the gear material 21, the annular shape of the upper mold 2210' and the lower mold 2220', and matches the outer diameter of the gear material 21. It has a predetermined inner diameter (D = 48 mm).

As shown in FIG. 14A, the gear material 21 is supported and arranged by the lower mold 2220'with the upper mold 2210'penetrating. As shown in FIG. 14 (b), the forged molded body 22'shown in FIG. 14 (c) is formed by pushing the upper mold 2210'by a predetermined amount.
The forged body 22'is provided with a hollow disk-shaped portion 210 and protrusions 220'protruding on both sides in the axial direction on the inner circumference of the hollow disk-shaped portion 210.
The plate thickness H3 of the hollow disk-shaped portion 210 can be adjusted by the pushing amount H1 of the upper mold 2210', and can be calculated by subtracting the pushing amount H1 from the plate thickness t of the gear material 21 ( See FIG. 14 (c)).
The protrusion 220'has a predetermined size H2 in the axial direction, and is formed so that the cross-sectional shape cut by the surface including the shaft is triangular. Further, the outer surface of the protrusion 220'in the radial direction is
Regardless of the cutting process described later, only the forging process constitutes the radial outer surface of the rim portion 220B.

<Cutting process (internal gear)>
Next, the cutting process of the internal gear 200B will be described with reference to FIG. In the second manufacturing method, the inner surface of the protruding portion 220'(see FIG. 15 (a)) formed by the forging step is cut to cut the inner surface of the hollow disk-shaped portion 210 on both sides in the axial direction. A first hollow cone-shaped portion 221B and a second hollow cone-shaped portion 222B are formed to form a rim portion 220B, and a rim portion forming body 23B is obtained. As shown in FIG. 15B, the rim portion 220B is formed so that the inner surface in the radial direction has a valley shape.

In the forging process of the second manufacturing method, the protruding portion is formed using the same die as the mold used in the forging step of the first manufacturing method, and then the entire surface of the protruding portion is cut in the cutting step. Thereby, the rim portion 220B may be formed. However, as described above, it is preferable to form one side of the rim portion 220B in the forging step and form the other side by cutting in the cutting step to obtain the rim portion 220B because the cutting amount can be reduced.

The internal gear 200B is obtained through the blank processing step, the forging step, the cutting step, and the gear cutting step described above. The internal gear 200B whose hardness needs to be increased is quenched in the next step. Further, for the tooth portion 230B that needs to be formed with higher accuracy, a finishing process such as cutting, grinding and polishing is performed lightly.

According to the second manufacturing method of the external gear 100A and the internal gear 200B of the present invention described above, the following effects are obtained in addition to the above-mentioned effects (4) and (6).

(7) The gear 100A (or 200B) is cut into a disc-shaped portion 110'or a hollow disc-shaped portion by cutting the protruding portion 120'(or 220') after the forging step and before the gear cutting step. Further included is a cutting step of forming a rim portion 120A (or 220B) having two hollow truncated cone portions 121A and 122A (or 221B and 222B) on both sides of the portion 210 in the axial direction. Thereby, the rim portion 120A (or 220B) can be formed by forging and cutting. Further, the hollow disk-shaped portion 110 (or 210) can be formed thinly without cutting. Therefore, compared to the case where the hollow disk-shaped portion and the rim portion are all formed by cutting without forging, the manufacturing time can be shortened and the cutting amount can be reduced, so that the decrease in tool life can be suppressed and the material yield can be reduced. Can be improved.

(8) Of the protrusions 120'(or 220') formed in the forging process of the gear 100A (or 200B), the surface on the disk-shaped portion 110'side or the hollow disk-shaped portion 210 side is a hollow truncated cone. It constitutes the surface of the disc-shaped portion 110'side or the hollow disc-shaped portion 210'side of the shaped portions 121A and 122A (or 221B and 222B), and is out of the protruding portions 120'(or 220') in the cutting process. , The surface opposite to the disk-shaped portion 110'or the side opposite to the hollow disk-shaped portion 210 is cut to form the rim portion 120A (or 220B). As a result, compared to the case where the rim portion is formed by cutting the entire surface of the protruding portion formed in the forging step, only one surface needs to be cut, so that the cutting amount can be reduced.

Next, the external gear 100C and the internal gear 200C according to the modified examples of the external gear 100 and the internal gear 200 of the present embodiment, and the manufacturing method of these gears will be described with reference to FIGS. 16 and 17. FIG. 16 is a diagram for explaining the external gear 100C and the internal gear 200C according to the modified example.

As shown in FIG. 16A, the external gear 100C includes a hollow disk-shaped portion 110, a rim portion 120C, and a tooth portion 130C.

The rim portion 120C is provided so as to project on both sides of the hollow disc-shaped portion 110 in the plate thickness direction at the radial outer end of the hollow disc-shaped portion 110. The rim portion 120C is configured so that the cross-sectional shape including the axial direction is triangular, the outer surface in the radial direction has a side surface shape of a cylinder, and the inner surface in the radial direction has a side surface shape of a truncated cone. Will be done. Therefore, the weight of the rim portion can be reduced as compared with the case where the shape of the rim portion is cylindrical.

The tooth portion 130C is provided on the radial outer surface of the rim portion 120A (the surface opposite to the hollow disk-shaped portion 110), and a plurality of teeth are formed on the tooth portion 130C. The tooth streaks of the tooth portion 130C may be parallel to or oblique to the axis.

As shown in FIG. 16B, the internal gear 200C includes a hollow disk-shaped portion 210, a rim portion 220C, and a tooth portion 230C.

The rim portion 220C is provided so as to project on both sides of the hollow disc-shaped portion 210 in the plate thickness direction at the radially inner end portion of the hollow disc-shaped portion 210. The rim portion 220C is configured so that the cross-sectional shape including the axial direction is triangular, the inner surface in the radial direction has a side surface shape of a cylinder, and the outer surface in the radial direction has a side surface shape of a truncated cone. Will be done. Therefore, the weight of the rim portion can be reduced as compared with the case where the shape of the rim portion is cylindrical.

The tooth portion 230C is provided on the radial inner surface of the rim portion 220C (the surface opposite to the hollow disk-shaped portion 210), and a plurality of teeth are formed on the tooth portion 230C. The tooth streaks of the tooth portion 230C may be parallel to or oblique to the axis.

According to the external gear 100C and the internal gear 200C according to the modification described above, the same effect as the above-mentioned effect (1) is obtained.

Next, a method of manufacturing a modified example for manufacturing the external gear 100C and the internal gear 200C according to the modified example will be described with reference to FIG.
FIG. 17 shows an outline of the manufacturing process of the external gear 100C and the internal gear 200C in the manufacturing method of the modified example. As shown in FIG. 17, the manufacturing process includes (1) blank processing process, (2) forging process, (3) gear cutting process, and (4) drilling process, and if necessary, quenching process and finishing process. I do. Since (1) the blank processing step and (4) the drilling step are the same as those in the first manufacturing method, and (2) the forging step is the same as in the second manufacturing method, the description thereof is omitted. Then, (3) the gear cutting process will be described.

<Tooth cutting process>
A tooth portion 130C composed of a plurality of teeth is formed on the radial outer surface of the forged body 12'obtained in the forging step by a gear cutting process using a hobbing machine, a rack machine, or the like.
Further, a tooth portion 230C composed of a plurality of teeth is formed on the radial inner surface of the forged body 22'obtained in the forging step by a gear cutting process using a pinion cutter or the like.

According to the manufacturing method of the modified examples of the external gear 100C and the internal gear 200C of the modified example of the present invention described above, the same effects as the above-mentioned effects (4) and (6) are obtained.

<Processing conditions>
Next, the result of confirming the processing conditions in the first manufacturing method of the present invention will be described. Table 1 below shows the strength, hardness, etc. of each test material. The thickness of each of the test materials is 4 mm.
In the forging process and the bending process, an 800KN servo press (manufactured by Aida Engineering Co., Ltd.) was used as the press device, and the press motion was a crank. The mold used was an SKD material. As the lubricating oil, the working oil of G-3456 was used.

Table 2 shows the results of confirming the processing conditions of the forging process for the external gear 100A using the test materials shown in Table 1, and Table 3 shows the results of confirming the processing conditions of the bending process.

In Table 2, H1 indicates the pushing amount (mm) of the upper mold 1210, H2 indicates the axial size (mm) of the protruding portion 120, and H3 indicates the hollow disk-shaped portion of the external gear 100A. The plate thickness (mm) of the disc-shaped portion 110'that is the same as the plate thickness of 110 is shown, and the relationship of H3 = t-H1 (plate thickness t of the gear material 11 = 4 mm) is satisfied (see FIG. 7). Further, ◯ indicates that the processing was successful, and × indicates the case where the upper mold could not be pushed in or the mold was damaged.
As shown in Table 2, by adjusting the pushing amount H1 of the upper mold 1210 for each test material, a disk-shaped portion 110'having a predetermined plate thickness H3 can be obtained. Further, in each test material, when the pushing amount H1 is made larger than 2.8 mm and the plate thickness H3 of the disc-shaped portion 110'is made smaller than 1.2 mm, the material does not flow. Divided forging could not be performed, and it could not be processed well. Similar results were shown even when the split flow forging die was used in the second manufacturing method and the manufacturing method of the modified example.

In Table 3, θ is the angle formed by the truncated cone-shaped generatrix of the upper mold 1210 with respect to the central axis, and the larger the amount of deformation of the protruding portion 120 in the outer diameter direction, the larger the angle (FIG. 3). See 8A). Further, ◯ indicates that the processing was successful, and × indicates that the protrusion 120 was stretched and the flange was deformed, so that the protrusion 120 and the disk-shaped portion 110'(hollow disk-shaped portion 110) were cracked. Show what has happened.
As shown in Table 3, until θ was 52.5 °, it was possible to perform good processing without causing cracks. Therefore, the sandwiching angle of the rim portion 120A can be set to 75 ° or more.

Table 4 shows the results of confirming the processing conditions of the forging process for the internal gear 200B using the test materials shown in Table 1, and Table 5 shows the results of confirming the processing conditions of the bending process.

In Table 4, H1 indicates the pushing amount (mm) of the upper mold 2210, H2 indicates the axial size (mm) of the protruding portion 220, and H3 indicates the hollow disk-shaped portion of the internal gear 200A. The plate thickness (mm) of 210 is shown, and the relationship of H3 = t-H1 (plate thickness t = 4 mm of the gear material 21 of the internal gear 200B) is satisfied (see FIG. 10B). Further, ◯ indicates that the processing was successful, and × indicates the case where the upper mold could not be pushed in or the mold was damaged.
As shown in Table 4, by adjusting the pushing amount H1 of the upper mold 2210 for each test material, a hollow disk-shaped portion 210 having a predetermined plate thickness H3 can be obtained. Further, in each test material, when the pushing amount H1 is made larger than 2.4 mm and the plate thickness H3 of the hollow disk-shaped portion 210 is made smaller than 1.6 mm, the material does not flow. Divided forging could not be performed, and it could not be processed well. Similar results were shown even when the split flow forging die was used in the second manufacturing method and the manufacturing method of the modified example.

In Table 5, θ is an angle formed by the truncated cone-shaped generatrix of the upper mold 2310B with respect to the central axis, and the larger the amount of deformation of the protrusion 220 in the inner diameter direction, the larger the angle (FIG. 10B). reference). Further, ◯ indicates that the protrusion 220 was successfully processed, and × indicates that the protrusion 220 was shrunk and the flange was deformed to cause a crack between the protrusion 220 and the hollow disk-shaped portion 210.
As shown in Table 5, until θ was 52.5 °, it was possible to perform good processing without causing cracks. Therefore, the sandwiching angle of the rim portion 220B can be set to 75 ° or more.

Although the gears of the present invention and the method for manufacturing the gears of the present invention have been described above with embodiments and examples, the present invention is not limited to the above-described embodiments and examples, and can be appropriately modified.

For example, in the above-described embodiment, an example of using the gear as a gear having a parallel axis or a gear having a crossing axis has been shown, but the gear may be used as a gear having a staggered axis.
Further, the gear of the present invention may be used in combination with a conventional gear.

100, 100A, 100B, 100C External gear (gear)
110, 210 Hollow disc-shaped parts 120A, 120B, 120C Rim parts 121A, 121B First hollow cone-shaped parts 122A, 122B Second hollow cone-shaped parts 130A, 130B, 130C Tooth parts 200, 200A, 200B, 200C internal gear (gear)
220A, 220B, 220C Rim part 221A, 221B First hollow cone-shaped part 222A, 222B Second hollow cone-shaped part
230A, 230B, 230C Tooth

Claims (5)

The hollow disk-shaped portion, the rim portion provided at the radial outer or inner end of the hollow disk-shaped portion, and the rim portion provided on the surface of the rim portion opposite to the hollow disk-shaped portion side. It is a method of manufacturing a gear provided with a tooth portion.
The material for gears is forged to form a disk-shaped portion or the hollow disk-shaped portion to be the hollow disk-shaped portion, and the radial outer end of the disk-shaped portion or the hollow disk-shaped portion. The forging step of forming the rim portion and the protruding portion to be the tooth portion by projecting to both sides in the plate thickness direction at the inner end portion in the radial direction of the above.
A gear cutting step of cutting the surface of the protruding portion on the side opposite to the side of the disk-shaped portion or the surface on the side opposite to the side of the hollow disk-shaped portion to form the tooth portion. Including
After the forging step and before the gear cutting step, the protruding portion is deformed in the radial direction, and two hollow cones are formed on both sides of the disk-shaped portion or the hollow disk-shaped portion in the axial direction. the rim portion bending step further method of manufacturing including tooth car to form with base-like portion. The hollow disk-shaped portion, the rim portion provided at the radial outer or inner end of the hollow disk-shaped portion, and the rim portion provided on the surface of the rim portion opposite to the hollow disk-shaped portion side. It is a method of manufacturing a gear provided with a tooth portion.
The material for gears is forged to form a disk-shaped portion or the hollow disk-shaped portion to be the hollow disk-shaped portion, and the radial outer end of the disk-shaped portion or the hollow disk-shaped portion. The forging step of forming the rim portion and the protruding portion to be the tooth portion by projecting to both sides in the plate thickness direction at the inner end portion in the radial direction of the above.
A gear cutting step of cutting the surface of the protruding portion on the side opposite to the side of the disk-shaped portion or the surface on the side opposite to the side of the hollow disk-shaped portion to form the tooth portion. Including
After the forging step and before the gear cutting step, the protruding portion is cut into two hollow truncated cone-shaped portions on both sides of the disk-shaped portion or the hollow disk-shaped portion in the axial direction. method of manufacturing a including tooth wheel cutting step of forming the rim portion having a. Of the protrusions formed in the forging step, the surface of the disk-shaped portion or the hollow disk-shaped portion is the side of the disk-shaped portion of the hollow truncated cone-shaped portion or the hollow circle. It constitutes the surface on the side of the plate-shaped part,
In the cutting step, of said protruding portion, according to claim 2, said disk-like portion of the rim portion are cutting surface opposite to the opposite side or the hollow disk-like portion is formed How to make gears. The method for manufacturing a gear according to any one of claims 1 to 3 , wherein the material for the gear is made of special steel or stainless steel. The method for manufacturing a gear according to any one of claims 1 to 3 , wherein the material for the gear is formed by processing from a special steel plate or a stainless steel plate.

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