WO2011111808A1 - Threaded electrodeposition tool and gear processing method using threaded electrodeposition tool - Google Patents

Abstract

Provided are a threaded electrodeposition tool and a gear processing method using the threaded electrodeposition tool. The threaded electrodeposition tool makes it possible for truing to be performed even with a truing grindstone that has a thick grinding part, and also for the accuracy of a base metal (11) or a post-truing threaded part (13) to be precisely and accurately measured. The threaded part (13), which is spirally twisted about an axis, is formed on the outer circumferential surface of the base metal (11) which is caused to rotate about the axis, and an abrasive grain layer is formed on the surface of the threaded part (13) by electrodepositing abrasive grains using a metal plating layer. A bottom land (17) is formed in the threaded part (13) by setting the pitch of a top land (12) of the threaded part (13) to 2 ?mx when an axial module of the threaded part (13) is set to mx(mx=m/cos?), where m denotes a normal module of a gear to be ground, and ? denotes a lead angle on a reference cylinder (P) of the threaded part (13).

Description

Threaded electrodeposition tool and gear machining method using threaded electrodeposition tool

The present invention has a screw-like electrodeposition tool that has a screw-like portion in which abrasive grains are electrodeposited on the outer peripheral portion of a base metal, and processes the tooth profile of a work gear, and a gear machining method using the screw-like electrodeposition tool About.
This application claims priority on March 12, 2010 based on Japanese Patent Application No. 2010-055961 filed in Japan, the contents of which are incorporated herein by reference.

As a tool for processing a gear tooth profile, for example, in Patent Documents 1 and 2, a screw-like portion is formed on the outer peripheral portion of a base metal having a substantially cylindrical outer shape, and superabrasive grains such as diamond and cBN are electroplated on the surface. An attached threaded electrodeposition tool is described. In such a screw-shaped electrodeposition tool, the toothed portion of the work gear is ground with superabrasive grains by meshing the screw-like portion with the work gear while rotating the base metal around its central axis. To form a tooth profile with the accuracy of

JP 2003-266241 A JP 2007-98527 A

By the way, in such an electrodeposition tool, truing is normally performed after electrodepositing superabrasive grains on a screw-like part, and the external shape of the thread in this screw-like part is corrected. That is, the shape of the envelope surface connecting the tips of the superabrasive grains protruding from the metal plating layer is formed so as to correspond to the tooth profile of the workpiece gear to be processed.
However, if the module m (pitch circle diameter d (mm) / number of teeth z) of the work gear to be machined by such a screw-shaped electrodeposition tool is reduced to, for example, about 1 or less, the electrodeposition tool of the electrodeposition tool is accordingly accompanied. The thread pitch in the threaded portion is also reduced. When the thread pitch is small as described above, in order to insert the truing grindstone into the gap of the thread and perform truing, the grinding portion of the truing grindstone must be formed extremely thin. For this reason, it becomes difficult to manufacture a truing grindstone while ensuring the rigidity required for the grinding part of the truing grindstone.

Also, in such a screw-shaped electrodeposition tool, when measuring the shape and dimensional accuracy of the base metal before truing and the thread-shaped part after truing, a measuring element is inserted into the screw-shaped part and brought into contact with the screw thread. Therefore, the dimensions of each part are measured. However, if the thread pitch of the threaded portion of the threaded electrodeposition tool is reduced as described above, it becomes difficult to insert the probe between the threads, and the accuracy of the threaded portion must be accurately measured. It becomes difficult.

The present invention has been made under such a background, and it is possible to perform truing even with a truing grindstone with a thick grinding part, and it is possible to accurately measure the accuracy of a base metal and a threaded part after truing. It is an object of the present invention to provide a threaded electrodeposition tool and a gear machining method using the threaded electrodeposition tool.

In the threaded electrodeposition tool of the present invention, a screw-like part spirally twisted around the axis is formed on the outer periphery of the base metal rotated around the axis, and abrasive grains are formed on the surface of the screw-like part. A screw-shaped electrodeposition tool electrodeposited by a plating layer, wherein an axial module of the screw-shaped portion with respect to a tooth perpendicular module m of a work gear and a lead angle γ on a reference cylinder of the screw-shaped portion is represented by mx In the case of (mx = m / cosγ), a thread escape portion (groove portion) is formed in the screw-like portion by setting the thread pitch of the screw-like portion to 2πmx. Further, the gear machining method of the present invention processes the work gear of the module m using the screw-shaped electrodeposition tool of the present invention.

In the conventional screw-shaped electrodeposition tool, for example, as shown in FIG. 4 of Patent Document 1, the screw-shaped portion 1 as shown in FIG. When the pitch of the screw thread 2 is mx (mx = m / cos γ), the axial direction module of the screw part 1 with respect to the module m of the work gear and the advance angle γ on the reference cylinder P of the screw part 1 , Πmx pitch. On the other hand, in the above-mentioned strip relief portion in the present invention, the pitch of this thread is set to a pitch of 2πmx which is twice that of the prior art. That is, for example, when compared with a conventional screw-shaped electrodeposition tool in which the thread of the thread-shaped portion is a double thread, the thread of one of the two threads is eliminated. That is, in the truing and measurement, a wide groove (stretching part) is formed between adjacent screw threads so as not to interfere with the truing grindstone and the measuring element.

Therefore, in this thread-shaped electrodeposition tool, it is possible to ensure a large gap between the adjacent screw threads in the axial direction and circumferential direction in the strip relief portion, so that even a general truing grindstone with a thick grinding portion can be used. The threaded electrodeposition tool can be manufactured reliably and easily. Further, since the measuring element can be easily inserted between the adjacent screw threads, the shape and dimensional accuracy of the screw-like portion can be accurately measured.

In addition, in the gear machining method of the present invention using such a screw-shaped electrodeposition tool, the teeth of the workpiece gear are not machined at the strip relief portion. However, when machining a work gear with an odd number of teeth, all teeth are machined while the work gear rotates. Further, in a work gear with an even number of teeth, all teeth can be machined by shifting the tooth part that is not machined in the first machining from the strip relief part and performing the second machining.

In the conventional threaded electrodeposition tool having a plurality of thread threads with a pitch of πmx in the threaded part, the strip relief part has a shape in which some of the plurality of thread threads are eliminated, For example, it may have a shape in which one of the three threads is eliminated. However, in order to ensure the truing of all the threads of the thread-like part and the measurement of the shape and dimensions, every other thread with an even number (2, 4, 6 ...) of pitch πmx It is desirable that all the screw threads of the screw-like portion are formed at equal intervals with a pitch of 2πmx in the axial direction by adopting the lost shape.

As described above, according to the present invention, even when machining a work gear with a small module, it is possible to provide a relatively wide relief portion between the threads of the threaded electrodeposition tool. By inserting a general truing grindstone with a thick grinding part into the relief part, truing of the screw-like part can be performed reliably. In addition, since the measuring element for measuring the shape and dimensions of the base metal before electrodeposition and the screw-like part after electrodeposition can be easily inserted into the strip relief part, it is easy to perform accurate measurement.

It is a side view which shows one Embodiment of the screw-shaped electrodeposition tool of this invention. It is the front view which looked at embodiment shown in FIG. 1 from the axis line O direction. FIG. 3 is a ZZ cross-sectional view in FIG. 1. It is an expanded sectional view along the axis line of the screw-shaped part of embodiment shown in FIG. It is a figure which shows one Embodiment of the gear processing method of this invention which processes a to-be-cut gear according to embodiment shown in FIG. FIG. 8 is a cross-sectional view corresponding to the ZZ cross-sectional view in FIG. 1, showing a first modification of the embodiment shown in FIG. 1. FIG. 10 is a cross-sectional view corresponding to the ZZ cross-sectional view in FIG. 1 showing a second modification of the embodiment shown in FIG. 1. It is an expanded sectional view in alignment with the axis line of the screw-shaped part of the conventional screw-shaped electrodeposition tool.

FIG. 1 shows a threaded electrodeposition tool according to an embodiment of the present invention. This screw-shaped electrodeposition tool has a base plate 11 having a substantially multi-stage columnar shape made of steel or the like, and a screw-like portion 13 is formed on the outer periphery of the base plate 11. The screw-like portion 13 has one or a plurality of threads 12 that are spirally twisted around the axis O of the base metal 11, and an abrasive layer is formed over the entire surface of the screw-like portion 13. In the abrasive layer, abrasive grains made of superabrasive grains such as cBN and diamond are electrodeposited onto the surface of the screw-like portion 13 in a substantially single layer by a metal plating layer such as Ni. Further, the abrasive grain layer is subjected to truing or semi-truing which removes excess abrasive grains only attached to the surface of the metal plating layer by electrodeposition in the same manner as truing.

A mounting hole 14 having a circular cross section that penetrates along the axis O is formed at the center of the base metal 11. Both end portions 15 of the base metal 11 have a cylindrical shape with an outer diameter smaller than the diameter of the valley between the screw threads 12 of the screw-shaped portion 13 over a certain width. A pair of key grooves 16 extending in the radial direction are formed symmetrically about the axis O. An abrasive layer is not formed on the surfaces (outer peripheral surface and end surface) of both end portions 15. The threaded electrodeposition tool is rotated about the axis O integrally with the rotation shaft by inserting a rotation shaft (not shown) into the mounting hole 14 and a key provided on the rotation shaft meshes with the key groove 16. Then, as shown in FIG. 5, it is used for tooth profile grinding of the work gear W.

In the screw-like portion 13, the axial module of the screw-like portion 13 with respect to the module m of the work gear W and the advance angle γ of the screw-like portion 13 on the reference cylinder P is mx (mx = m / cosγ). In this case, as shown in FIG. 4, the pitch of the screw threads 12 is set to 2πmx, so that the relief portions 17 are formed between the screw threads 12. The screw-like portion 13 in the present embodiment is a screw having two threads 2 having a pitch of πmx with respect to the module m of the gear to be cut, such as the conventional screw-shaped electrodeposition tool shown in FIG. As shown in FIG. 1 to FIG. 3 by hatching and as shown by broken lines in FIG. 4 and FIG. The shape is lost, that is, recessed. A portion corresponding to the removed screw thread 2 is a strip relief portion 17, and a pitch of the remaining screw thread 12 is 2πmx. Of course, the thread 2 may be formed once in the base 11 and then removed so as to be scraped off, and then the abrasive grains may be electrodeposited. As will be described later, the thread 2 is not provided from the beginning. Abrasive grains may be electrodeposited after processing the base 11 into a shape.

FIG. 5 shows an embodiment of the gear machining method of the present invention. When machining the work gear W of the module m with the screw-shaped electrodeposition tool, the thread 12 of the screw-like portion 13 is engaged with the teeth of the work gear W, and the base 11 is rotated around the axis O. At the same time, the work gear W is also rotated in synchronism around the center line X, and is cut by the incision by the abrasive layer. As a result, the teeth of the work gear W are processed with the tooth surfaces facing each other adjacent teeth meshing with every other thread 12 in this embodiment. The gear grinding machine may be input with the number of threads before the thread 2 is released as a threaded electrodeposition tool, and the tool mounting angle may be the same as that before the thread 2 is released.

The tooth surface of the work gear W positioned at the strip relief portion 17 is not ground because the meshing thread 12 is released, but if the number of teeth of the work gear W is an odd number, the work gear When W makes one rotation around the center line X, it meshes with the thread 12 and, as a result, the tooth surfaces of all the teeth of the work gear W are ground. Further, when the number of teeth of the work gear W is an even number, after the processing of the corresponding tooth surfaces of every other tooth is finished, the tooth meshing with the screw thread 12 is shifted by one and the processing is performed again. That's fine.

Thus, even with the screw-shaped electrodeposition tool having the above-described configuration, if the machining conditions are the same, the machining time is longer than the conventional one, but the grinding of the work gear W can be performed in the same manner as the conventional one regardless of the number of teeth. it can. Moreover, what is necessary is just to double the rotation speed of the screw-shaped electrodeposition tool or the to-be-cut gear W in order to make processing time the same.

In the screw-shaped electrodeposition tool having the above-described configuration, since the strip relief portion 17 is formed in the screw-shaped portion 13, it is possible to ensure a large interval in the axis O direction and the circumferential direction of the adjacent screw threads 12. For this reason, even when the module m of the work gear W is as small as 1 or less, for example, truing or semi-truing is applied to the threaded portion 13 on which the abrasive grains are electrodeposited. Without using a truing grindstone with a very thin wall thickness and a low rigidity, it is possible to reliably and easily insert a truing grindstone with a thick grinding part and a high rigidity into the escape part 17, and A threaded electrodeposition tool can be manufactured by truing with high accuracy.

Further, when measuring the shape and size of the thread 12 in the threaded portion 13 thus threaded or the threaded portion 13 of the base 11 before electrodepositing the abrasive grains, a large cut of the module m Even with a measuring element for a threaded electrodeposition tool of a gear, it is possible to measure the thread 12 by inserting it into the strip relief portion 17. Therefore, according to the screw-shaped electrodeposition tool having the above-described configuration, the shape and dimensional accuracy of the screw-shaped portion 13 can be accurately measured, and the accurate screw-shaped electrodeposition tool can be used for machining the work gear W. By using such a screw-shaped electrodeposition tool, according to the gear machining method of the present invention, it is possible to improve the machining accuracy of the work gear W.

In the present embodiment, the strip relief portion 17 is one of the even two threads 12 and 2 having a pitch of πmx with respect to the module m of the work gear W as described above. 2, and the remaining screw threads 12 are formed at equal intervals in the direction of the axis O at a pitch of 2πmx. If formed, for example, one of the three threads 12, 2 having a pitch of πmx may be released to form the thread relief portion 17. In the strip relief portion 17, truing can be surely and easily performed, and measurement with high accuracy can be performed.

However, in such a screw-shaped electrodeposition tool, the pitch of the remaining two threads 12 remains πmx, which makes truing and measurement difficult, and is therefore processed by such a screw-shaped electrodeposition tool. Since there is a possibility that the processing accuracy of the tooth surface may vary in the work gear, as in the present embodiment, the shape in which every other screw thread 2 of the even number of screw threads 12 and 2 with a pitch πmx is eliminated, It is desirable that the remaining screw threads 12 are formed at equal intervals in the direction of the axis O with a pitch of 2πmx.

In the present embodiment, by removing one of the two threads 12 and 2 having a pitch of πmx and forming the thread relief 17, the remaining thread 12 is moved in the direction of the axis O. For example, in the case where the thread relief portion 17 is formed on the screw-shaped portion 13 having four thread threads 12 and 2, the pitch is 2πmx. As in hatching 1, every other two threads 2 are eliminated to form a thread relief 17, and a thread relief 13 is formed on a thread 13 having six threads 12, 2. In this case, as in the second modification shown in FIG. 7, every other three threads 2 are eliminated to form the strip relief portion 17.

Further, in the above-described embodiment, since the strip relief portion 17 does not participate in the machining of the work gear W, for example, masking is performed when electrodepositing abrasive grains so that the abrasive grain layer is not formed. Good. Further, in the above-described embodiment, the strip relief portion 17 has a shape in which every other screw thread 2 is removed by scraping to the diameter of the thread root of the screw-like portion 13 with respect to the screw thread 12 as described above. That is, it is formed so as to form a cylindrical surface centered on the axis O, but since the strip relief portion 17 is not involved in processing, the cross section along the axis O is formed to be recessed toward the inner peripheral side. Alternatively, as long as the truing and measurement are not hindered as long as they are not involved in processing, a slightly convex portion may be left on the outer peripheral side.

Furthermore, in the present embodiment, a threaded electrodeposition tool having a threaded portion 13 in which a plurality of threads 12 and 2 are formed at a pitch of πmx or a base 11 is formed in advance, and the thread 2 The strip relief portion 17 is formed by scraping only the electrode, and abrasive grains are electrodeposited on a base metal 11 in which only the thread 12 is formed on the thread-like portion 13 at a pitch of 2πmx from the beginning. The relief portion 17 may be formed between the two.

According to the present invention, even when machining a work gear with a small module, a relatively wide strip relief portion can be provided between the threads of the threaded electrodeposition tool. By inserting a typical truing grindstone into the strip relief portion, it becomes possible to reliably perform truing of the screw-like portion. In addition, since the measuring element for measuring the shape and dimensions of the base metal before electrodeposition and the screw-like part after electrodeposition can be easily inserted into the strip relief part, it is easy to perform accurate measurement. Therefore, it has industrial applicability.

11 Base 12 Thread 13 Threaded portion 17 Thread relief O Axis of base 1 W Work gear X Center line of work gear W

Claims (4)

A screw-like portion formed by spirally twisting a screw around the axis is formed on the outer periphery of the base metal rotated around the axis, and abrasive grains are electrodeposited on the surface of the screw-like portion by a metal plating layer. In the case of an electrodeposition tool, the axial module of the threaded portion relative to the tooth perpendicular module m of the work gear and the advance angle γ of the threaded portion on the reference cylinder is mx (mx = m / cosγ) The threaded electrodeposition tool is characterized in that a thread relief portion is formed in the threaded portion by setting the thread pitch of the threaded portion to 2πmx. 2. The screw-shaped electrodeposition tool according to claim 1, wherein all screw threads of the screw-shaped portion are formed at equal intervals with a pitch of 2πmx in the axial direction. A gear machining method using a screw-shaped electrodeposition tool, characterized in that the work gear of the module m is machined using the screw-shaped electrodeposition tool according to claim 1 or 2. The gear machining method according to claim 3, wherein the thread of the threaded portion is meshed with teeth of the work gear, the threaded electrodeposition tool is rotated about its axis, and the work gear is A gear machining method using a screw-like electrodeposition tool, wherein the tooth of the workpiece gear is ground by the abrasive layer by rotating around the center line.

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