JPH0739986A - Method for manufacturing shaft with gears supported at both ends - Google Patents

Abstract

(57) [Abstract] [Purpose] In the manufacturing method of a shaft with gears supported at both ends, the manufacturing process is improved by improving the coaxial accuracy of the shaft, especially the coaxiality of both bearing support parts and gear parts, and eliminating grinding of the outer peripheral part. Rationalize. [Structure] A blank 11 is cold-forged into a shape close to a finished product, and the blank 11 is cold-forged to have three bearing support parts 1 and 5 and a gear part 2, and further, a commutator fitting part 4 and an armature. The core fitting part 3 is simultaneously finished by a set of molds, the obtained blank is subjected to curing heat treatment, and further, the scale formed on the surface of the blank by the curing heat treatment is removed by shot blasting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a shaft with a gear supported at both ends, and more particularly to a method for manufacturing an armature shaft with a gear supported at both ends which is suitable for use in a starter motor (engine starting device).

[0002]

2. Description of the Related Art Generally, in a conventional shaft with a gear supported at both ends, a gear is formed by cutting a blank after forging, as described in JP-A-4-4308.

Further, in the prior art disclosed in Japanese Patent Laid-Open No. 2-303648, a bearing bearing portion is provided at one end, a gear portion is provided at the other end, and another bearing bearing portion is provided following the gear portion. In the provided armature shaft manufacturing method, it has been proposed to form the gear portion by cold forging. When manufacturing a shaft with both ends supported type gear by applying this manufacturing method, for example, the gear part is formed long in advance, the gear part is cut and processed to form the bearing support part, and after hardening heat treatment, both bearing support parts are formed. The part and the commutator fitting part are manufactured by a grinding process.

[0004]

However, in the above-mentioned prior art, since each bearing support part is cut and ground one by one, and the gear part and the gear part are finished in separate steps, respectively.
The coaxial precision of each bearing support part and the gear part was low, and when assembled in the motor with both ends supported, the gear noise was large, and there were problems in product performance such as gear damage and uneven wear of the bearing. Also, as mentioned above, both bearing support parts are
Since it is not possible to cut or grind at the same time, a large number of processing man-hours and a large number of expensive processing machines are required, resulting in high cost.

It is an object of the present invention to improve the coaxial accuracy of the shaft, particularly the coaxiality of both bearing support portions and the gear portion, and to streamline the manufacturing process by eliminating the grinding of the outer peripheral portion. And a method for manufacturing an armature shaft with a gear supported at both ends.

[0006]

In order to achieve the above object, the present invention relates to a double-ended support type geared shaft having bearing support portions at both ends, and a gear portion being provided following one of the support portions. In the manufacturing method, (a) a first step of cold forging a rod-shaped blank to form a flanged blank having a shaft portion at both ends and a flange portion following one of the both end shaft portions;
(B) At least three shaft portions of the flanged blank obtained in the first step and the flange portion are simultaneously cold forged in one set of dies, and these are directly connected to the bearing support portions and the gears. And (c) a third step of hardening and heat treating the blank obtained in the second step.

Further, according to the present invention, bearing supporting portions are provided at both ends, a gear portion is provided following one of the supporting portions, and a commutator fitting portion and an armature are provided between the gear portion and the other supporting portion. In a method of manufacturing an armature shaft with a gear supporting both ends provided with a core fitting portion, (a) a rod-shaped blank is cold forged, has shaft portions at both ends, and one of the both end shaft portions is followed by a collar. A first step of forming a flanged blank provided with parts; and (b) simultaneously cooling at least three end shaft parts and a flange part of the flanged blank obtained in the first step in one set of molds. And a third step of (c) hardening and heat-treating the blank obtained in the second step. To do.

In the above-mentioned method for manufacturing the armature shaft with both ends supporting type gear, preferably, the commutator fitting portion and the armature core fitting portion are the same when finishing the bearing supporting portion and the gear portion by cold forging. Finish by cold forging at the same time in a pair of dies. Further, preferably, after both the bearing support portion, the gear portion, the commutator fitting portion, and the armature core fitting portion are simultaneously finished by cold forging, the commutator fitting portion and the armature core fitting portion are Imprint impression.

Further, preferably, the scale formed on the surface of the blank by the heat treatment for curing may be removed by shot blasting.

[0010]

According to the present invention constructed as described above, the blank is cold-forged into a shape close to a finished product having shaft portions at both ends and a flange portion following one of the shaft portions at both ends. At the same time, by cold forging at least 3 parts of the shaft part and flange part of the attached blank in one set of dies at the same time, and directly finishing them into both bearing support parts and gear parts, these 3 parts are finished at the same time. You can make them almost coaxial. Further, since the diameter dimension is also determined by the mold, the variation in dimension is extremely small, and the grinding process of the outer peripheral portion is unnecessary.

Further, when the bearing support portion and the gear portion are molded, the commutator fitting portion and the armature core fitting portion are finished by cold forging at the same time, so that the commutator fitting is performed in addition to the bearing bearing portion and the gear portion. The joint portion and the armature core fitting portion can be made substantially coaxial, and the grinding process for them is not necessary.

Further, by imprinting impression marks on the commutator fitting portion and the armature core fitting portion, Japanese Patent Publication No. 59-59-
The armature core and the commutator can be fitted and joined to the armature core fitting portion and the commutator fitting portion by the impression mark using the method described in Japanese Patent No. 38861.

When both the bearing support parts are slide bearings, the life of the bearings can be extended at low cost by removing the scale by heat treatment by shot blasting.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is an example of an armature shaft with a gear supported at both ends manufactured by the method of the present embodiment. An armature shaft 15 has bearing bearings 1 and 5 at both ends thereof which are rotatably fitted to slide bearings and transmits a rotational force. A gear portion 2, a collar 18 used during cold forging, an armature core fitting portion 3 having an impression mark 8 for fitting an armature core,
It is composed of a commutator fitting portion 4 provided with a coining mark 9 for fitting a commutator, and has center holes 6 and 7 on both end faces which are required in an armature assembly process.

FIG. 2 shows an example of an armature rotor constructed by using the above-mentioned armature shaft 15. An armature rotor 69 is fitted with an armature core 70 and a commutator 71 having a laminated structure on the armature shaft 15 (the collar 18 is cut and removed). Are combined and configured. FIG. 3 is an example of a planetary reduction type starter motor configured by using the armature rotor 69. The armature shaft 15 assembled in the armature rotor 69 is fitted in the slide bearing 73 of the bracket 72 and the slide bearing 75 of the pinion shaft 74. The gear unit 2 meshes with the three planetary gears 76. The pinion shaft 74 is provided with a pinion gear 78 that rotates via a one-way clutch 77. The one-way clutch 77 and the pinion gear 78 are pushed forward by a shift lever 80 operated by a magnet switch 79 and mesh with a ring gear of an engine (not shown). .

FIG. 4 shows an example of the manufacturing process of the armature shaft 15. First, the case hardened steel coil material 30 such as SCM415 is supplied to the multi-stage part former,
Is cut into a required length to obtain the material 10. The multi-stage part former has a cutting device for cutting the coil material 30 and also has a built-in multi-stage, for example, four-stage, mold device that opens and closes at the same time, and the material 10 obtained by the cutting device is the mold. It is sequentially sent to the apparatus and cold forged (intermediate steps are not shown) to obtain a blank 11 having both-end shaft portions 1a and 5a, intermediate shaft portions 3a and 4a, and a collar portion 18a. By cold forging the blank 11 with a parts former as described above, the blank 11 with stable accuracy can be manufactured at a good yield and at a low cost.

The blank 11 is then subjected to step 32 for softening purposes.
Annealing in step 33, bonder processing is performed in step 33, and a hydraulic press is used in cold forging step 34 with a die as shown in FIGS. 5 and 6 to mount both bearing support parts 1, 5, gear part 2, armature core fitting. The part 3 and the commutator fitting part 4 are simultaneously molded and finished to obtain the shaft 12. At this time, the center holes 6 and 7 are also molded in the mold. This molding process will be described in detail later. Since the shaft 12 formed in the cold forging step 34 has a surplus amount due to the volume variation at the time of cutting in the axial length of the bearing support portion 1, the end surface 16 of the bearing support portion 1 is machined in the step 35. Then, the shaft 13 is obtained by removing and adjusting. Further, when the armature shaft has a groove for retaining ring, for example, the groove may be processed in this step 35. Further, the collar 18 may be removed if necessary.

Next, the impression marks 8 and 9 as described in Japanese Patent Publication No. 59-38861 are provided with the armature core fitting portion 3,
The shaft 14 is obtained by simultaneously molding the commutator fitting portion 4. Further, the shaft 14 is sent to the step 37 for carburizing and quenching. At this time, a hard scale is formed on the outermost surface layer, which may impair the slidability. Therefore, in step 38, shot blasting is performed using a projection material 40 such as glass beads on both bearing support portions 1 and 5 to scale the scale. Remove. Instead of shot blasting, a brush may be used to remove the scale. In this way, the above armature shaft 15 is obtained.

In the above embodiment, the shaft material is SC.
The coil material 30 of case hardening steel such as M415 was used, but instead of it, S35C, S38C, SCM435, etc. were used, and instead of the above carburizing and quenching 37, both bearing support parts 1, 5 and gear part 2 were induction hardened. However, in this case as well, when the scale adheres, the scale may be removed by the above method.

Further, although dimensional expansion occurs due to quenching,
If the quenching conditions are the same, the amount is constant, so it is sufficient to anticipate the amount from the beginning.For bending, the bending at both ends is very small. Bending does not have to be taken into consideration because bending does not occur.

The forming process in the cold forging process 34 will be described with reference to FIGS. 5 and 6. FIG. 5 shows a state after the blank 11 is inserted into the mold and before press molding, and FIG. 6 shows a state before main press molding is completed at the bottom dead center position of the main press and before sub press molding.

The lower mold is a die (A) 53 and a die (A) 5.
3, the ring punch 52 and the die (B) 5 which are press-fitted to each other.
4, the ring punch 52 has a mold part 45 for molding the armature core fitting part 3, and the die (B) 54 has mold parts 46, 47 for molding the commutator fitting part 4 and the bearing support part 5. Have These mold parts 45, 46, 4
The diameter of 7 is the diameter of the shaft portions 3a, 4a, 5a of the blank 11 (in the present embodiment, 16 mm, 12.5 mm, 11 m, respectively).
m) to be about 0.02 to 0.12 mm larger. The dice (A) 53 and the dice (B) 54 actually have a multi-fitted die structure in which a plurality of parts are combined. The center part 56 is provided on the die (B) 54.
A lower center pin 55 having a is fitted slidably. Below the die (B) 54, there is a die sink 20, and these lower dies are fastened by holders 21 and 22 fastened to the press bolster side so that no gap is created on the fitted die surface even during molding. ing. Holder 22 is holder 2
It is fastened to the upper part by screw parts 21A and 22A.

The upper die is a gear die 51 and an upper center pin 5
7, a gear die 23 and an auxiliary hydraulic cylinder device 24 forming an auxiliary press, and are fastened by holders 25 and 26 fastened to the press ram side. Gear die 5
Actually, 1 also has a multi-fitted die structure formed by combining a plurality of parts. Further, the holder 26 is fastened on the holder 25 with screw portions 25A and 26A. The flange portion 18a of the blank 11 is inserted into the gear die 51, and the extrusion hole 27 into which the ring punch 52 is fitted, the extrusion taper portion 28, the gear mold portion 29, the ironing hole 41 and the upper center pin 57 are slidably fitted together. Guide hole 4
Two are provided. Here, the fitting between the ring punch 52 and the extrusion hole 27 is preferably press fit to prevent the ring punch 52 from being damaged, and the press fit margin is set according to the molding stress. In addition, it is desirable that the extrusion hole 27, the gear mold 29, and the ironing hole 41 have a separate structure in the gear die 51 as needed in terms of mold life and mold manufacture. Also, in order to prevent the lubricant applied during molding from being trapped in the space 90 (see FIG. 6) between the gear part 2, the gear mold part 29, the bearing support part 1 and the ironing hole 41 during the molding process, the mold may be damaged. A structure is provided in which a small groove is provided for each gear, and the oil holes 62 provided at three equally spaced parts are connected to discharge the lubricating oil.

As shown in FIG. 7, the ironing hole 41 has a tapered introduction portion 41 having an introduction diameter d and an introduction angle α.
A, an ironing land 41B following the introducing portion 41A, and an escape portion 41C having an escape δ with respect to the ironing land 41B. The escape portion 41C is a guide hole 42 of the upper center pin 57.
Connected to. The introduction diameter d is the convex portion 1a of the blank 11.
It is preferable that the introduction angle α is 35 ° or less in order to reduce the introduction resistance and the ironing resistance, since the diameter is larger than the diameter (8 mm in this embodiment) and the coaxial accuracy is taken into consideration. The ironing allowance of the diameter of the ironing land 41B is about 0.05 to 0.15 mm, the length of the ironing land 41B is about 1 to 2 mm, and the clearance δ of the relief portion 41C is about 0.01 to 0.03 mm. good.

In the molding process, first, the press ram (not shown) descends from the state shown in FIG. 5, the extrusion hole 27 is fitted into the collar portion 18a, the ring punch 52 is then press-fitted, and the upper surface 80 of the flange portion is tapered. Touch the entrance of section 28,
When pressure is applied, the blank 11 is pushed into the center part 56 to form the center hole 7, the ring punch end face 81 and the lower face 19 of the flange part contact each other, and the flange part 18a is pushed out to the gear mold part 29, while the shaft parts 3a, 4a, Pressure is generated in the radial direction of the shaft 5a to fill the mold parts 45, 46, 47, and the armature core fitting part 3, the commutator fitting part 4, the bearing support part 5 are formed.
Form the shaft diameter of. At this time, since the outer diameter of the shaft portion 1a is smaller than the small diameter of the gear mold portion 29, it does not contact the gear mold portion 29. As the flange portion 18a is further pushed out into the gear mold portion 29, the shaft portion 1a is squeezed by the squeezing hole 41, and the plastic flow is completed as shown in FIGS. 6 and 7.

In this state, the auxiliary hydraulic cylinder device 24 is operated and the upper center pin 57 is pushed by the auxiliary cylinder 59 to form the center hole 6. At this time, in order to prevent the deformation of the bearing support portion 1, it is preferable to hold the main press at the bottom dead center position as shown in FIG. 6 until the molding of the center hole 6 is completed.

Even when the armature shaft 12 is taken out from the mold, in order to prevent the bearing support portion 1 from being deformed, the resistance is controlled so that the armature shaft 12 remains in the lower mold by applying the lubricating oil only to the upper mold side. Then, the lower center pin 55 may be pushed up by a lower ejecting device (not shown) and taken out.

According to the present embodiment configured as described above,
The blank 11 with a collar is cold forged into a shape close to a finished product, and the shaft portions 1a and 5a at both ends of the blank 11 with a collar and the collar portion 18a are formed.
, And the intermediate shaft portions 3a and 4a are simultaneously cold forged in one set of dies, and these are directly connected to both bearing support portions 1 and 5, gear portion 2, armature core fitting portion 3a and commutator. Since they are finished with the fitting portion 4a, they can be made substantially coaxial. Further, since the diameter dimension is also determined by the mold, the dimensional variation can be extremely reduced, and the grinding process of the outer peripheral portion is unnecessary. As a result, the manufacturing work process can be rationalized, the manufacturing cost can be significantly reduced, and the armature shaft 15 having high coaxial accuracy can be obtained.

Further, by processing the impression marks 8 and 9 on the armature core fitting portion 3 and the commutator fitting portion 4,
As shown in FIG. 2, the armature core fitting portion 3 and the commutator fitting portion 4 are formed on the armature core fitting portion 3 and the commutator fitting portion 4 at the impression marks 8 and 9 by using the method described in JP-B-59-38861.
Also, the commutator 71 can be fitted and coupled.

Further, when both bearing support parts 1 and 5 are supported by sliding bearings 75 and 73 as shown in FIG. 3,
By removing the scale formed by heat treatment by shot blasting, the bearing life can be extended at low cost.

[0031]

As described above, according to the present invention, it is possible to rationalize the manufacturing work process and significantly reduce the manufacturing cost, and to obtain a shaft with a gear having both ends supported and having high coaxial precision.

Further, when the bearing supporting portion and the gear portion are molded, the commutator fitting portion and the armature core fitting portion are finished by cold forging at the same time, so that the commutator fitting portion is added to the bearing bearing portion and the gear portion. The joint portion and the armature core fitting portion can be made substantially coaxial, and the grinding process for them is not necessary.

Further, the armature core and the commutator can be coupled to the commutator fitting portion and the armature core fitting portion by using the impression mark described in Japanese Patent Publication No. 59-38861.

Further, in the case where both bearing support parts are slide bearings, by removing the scale by heat treatment by shot blasting, the bearing life can be extended at low cost.

[Brief description of drawings]

FIG. 1 is a perspective view of an armature shaft with a double-ended support type gear manufactured according to an embodiment of the present invention.

FIG. 2 is a partial vertical cross-sectional view of an armature rotor incorporating a double-sided support type geared armature shaft.

FIG. 3 is a partial vertical cross-sectional view of a planetary reduction type starter motor that incorporates an armature shaft with a gear supported at both ends.

FIG. 4 is a manufacturing process diagram showing a manufacturing method of an armature shaft with a gear supported at both ends according to an embodiment of the present invention.

FIG. 5 is a partial vertical cross-sectional view of a mold showing a state before starting press molding in the cold forging step of FIG.

FIG. 6 is a partial vertical cross-sectional view of a mold showing a state before main press molding is completed (main press bottom dead center position) in the cold forging step of FIG. 4 and before sub press molding.

7 is a partially enlarged view of the gear die portion shown in FIGS. 5 and 6. FIG.

[Explanation of symbols]

 1, 5 ... Bearing support part 2 ... Gear part 3 ... Armature core fitting part 4 ... Commutator fitting part 8, 9 ... Imprint mark 10 ... Material 11 ... Convex blank 15 ... Armature shaft 18 ... Tsuba 1a, 5a ... Shaft Part 3a, 4a ... Shaft part 18a ... Collar part 30 ... Coil material 31 ... Parts forming process 32 ... Annealing process 33 ... Bonding process 34 ... Cold forging process 35 ... Cutting process 36 ... Imprinting process 37 ... Carburizing and quenching Process 38 ... Shot blasting process

Claims (5)

[Claims] 1. A method for manufacturing a shaft with gears having both ends having bearing bearings at both ends, wherein a gear portion is provided following one of the bearings, wherein (a) a rod-shaped blank is cold forged, A first step of forming a flanged blank having shaft portions at both ends and a flange portion following one of the both end shaft portions; and (b) at least both ends of the flanged blank obtained in the first step. A second step of cold forging the shaft portion and the flange portion at the same time in one set of dies to directly finish them into the bearing supporting portion and the gear portion; (c) Obtained in the second step And a third step of hardening and heat treating the obtained blank. 2. A bearing bearing portion at both ends, a gear portion is provided following one of the bearing portions, and a commutator fitting portion and an armature core fitting portion are provided between the gear portion and the other of the bearing portions. In a method for manufacturing an armature shaft with a gear having both ends supported, wherein (a) a rod-shaped blank is cold forged, shaft portions are provided at both ends, and a collar portion is provided following one of the both end shaft portions. A first step of forming into a flanged blank; (b) cold forging at least three positions of the shaft portion and the flange portion of the flanged blank obtained in the first step at the same time in one set of dies. A double-end support type, characterized in that it has a second step of directly finishing these into the bearing support portion and the gear portion, and (c) a third step of hardening and heat-treating the blank obtained in the second step. Manufacturing method of armature shaft with gear. 3. The method for manufacturing an armature shaft with a gear supported at both ends according to claim 2, wherein the commutator fitting portion and the armature core fitting portion are used when finishing the bearing supporting portion and the gear portion by cold forging. A method for manufacturing an armature shaft with double-ended support gears, which is characterized in that cold forging is simultaneously performed in the same set of dies. 4. The method for manufacturing an armature shaft with a gear supported at both ends according to claim 3, wherein both the bearing support portions, the gear portion, the commutator fitting portion, and the armature core fitting portion are cold forged at the same time. A method for manufacturing an armature shaft with a double-ended support type gear, characterized in that the commutator fitting portion and the armature core fitting portion are subjected to coining after finishing. 5. The method of manufacturing an armature shaft with a gear having both ends supported type according to claim 2, wherein the scale formed on the surface of the blank by the hardening heat treatment is removed by shot blasting. Armature shaft manufacturing method.