JP2010201493A - Rolling die and method of working internal gear - Google Patents

Abstract

A rolling die and an internal gear machining method capable of reducing the influence of waviness generated on a tooth surface while increasing the machining surface pressure on the gear.
A rolling die for machining an internal gear having a plurality of teeth with serrations on the tooth surface and differential serrations in which the positions of lands 5 of the serrations are sequentially shifted in the direction of the teeth. For one tooth of the internal gear to be processed, the displacement direction of the position of the land 5 acting at the time of the next rotation with respect to the position of the land acting at the time of the rotation of the internal gear, and the land acting at the next rotation of the internal gear The direction of deviation of the position of the land acting at the next rotation with respect to the position of is reversed. Each time the internal gear rotates, the internal gear is machined while changing the direction of displacement of the land 5 alternately in the reverse direction along the tooth trace direction.
[Selection] Figure 5

Description

  The present invention relates to a rolling die for finishing a tooth surface of a gear and an internal gear processing method using the rolling die.

The rolling die for finishing the gear is formed in substantially the same shape as the gear, and is brought into contact with the tooth surface of the gear to be processed while pressure is applied, and the rolling die is rotated to rotate the gear. The shape of the teeth formed in advance is adjusted. The teeth of this type of finishing rolling die usually have a so-called solid shape with no irregularities on the surface.
However, when finishing a gear with this type of rolling die, it is necessary to press the rolling die against the tooth surface of the gear with a high surface pressure sufficient to plastically deform the gear. It is necessary to support the rolling die with a strong force, which is not suitable for processing a gear having a wide tooth width.

For this reason, a rolling die having serrated teeth in which a plurality of grooves substantially perpendicular to the tooth streaks are formed at intervals in the tooth surface so that even a gear having a relatively wide tooth width can be easily processed can be considered. (See Patent Document 1 below, but Patent Document 1 shows an example of a shaving cutter, not a rolling die).
In this type of rolling die, since a plurality of grooves are formed on the surface of the tooth, even when the tooth is pressed against the gear with a relatively small pressure, a relatively high surface pressure can be secured in the processing region. As a result, there is an advantage that even a gear having a relatively wide tooth width can be easily processed.

Japanese Patent Publication No. 48-26276

By the way, as in the conventional die described in Patent Document 1, for example, the positions of the pressing portions of the serrations acting on the first rotation, the second rotation,. In the case where the amount is shifted in the same direction by the amount (differential amount), there are the following problems.
That is, in order to process the entire tooth width with a die, it is necessary to rotate the gears at least as much as the deviation amount reaches the serration pitch (groove pitch or land surface pitch arranged between the grooves). For this reason, during the machining period in which vanishing is performed by reducing the distance between the rolling dies and the gear shaft, which is called plunge feed, at the initial stage of machining between serration pitches (the first rotation of the gear to be machined) and at the end of machining ( For example, a machining allowance of about 5 to 15 μm is generated at the final rotation of the work gear, and as a result, a swell of about 5 to 15 μm is generated on the tooth surface of the gear at the same period as the serration pitch.

  The present invention has been made under such a background, and provides a rolling die and an internal gear machining method capable of reducing the influence of waviness generated on the tooth surface while increasing the machining surface pressure on the gear. The purpose is that.

  In order to solve the above problems and achieve such an object, the rolling die of the present invention has a plurality of teeth with serrations on the tooth surface, and the position of the pressing portion of the serrations is a tooth trace. In a rolling die for machining an internal gear that is sequentially shifted in the direction to be differential serration, with respect to one tooth of the internal gear to be machined, the position relative to the position of the pressing portion that acts when the internal gear rotates. The direction of displacement of the position of the pressing portion acting during rotation of the internal gear is opposite to the direction of displacement of the position of the pressing portion acting during further rotation with respect to the position of the pressing portion acting during the next rotation of the internal gear. It is characterized by becoming.

  An internal gear machining method of the present invention is an internal gear machining method for machining an internal gear using a rolling die according to any one of claims 1 to 4, wherein one tooth of the internal gear is The displacement direction of the position of the pressing portion acting at the time of the next rotation relative to the position of the pressing portion acting at the time of one rotation of the internal gear, and further to the position of the pressing portion acting at the time of the next rotation of the internal gear. The direction of displacement of the position of the pressing portion acting during rotation of the pressing portion is reversed, and the internal gear is then processed while alternately changing the direction of displacement of the position of the pressing portion in the opposite direction for each rotation of the internal gear. It is characterized by that.

According to the processing method of the rolling die or the internal gear, since the serration is provided on the tooth surface, the processing surface pressure is increased as compared with the case of processing using a solid tooth surface without serration. Result processing becomes easy. Since the direction of deviation of the position of the serration pressing portion is alternately reversed every time the internal gear rotates, the tooth surface of the internal gear is pressed against other serrations in the middle of the actual serration pitch. Acts as if there is a part. For this reason, the undulation generated on the tooth surface of the internal gear has a shorter cycle than the actual serration pitch, and the machining margin error at that time can be reduced.

Here, with respect to one tooth of the internal gear to be processed, the displacement amount of the position of the pressing portion acting at the next rotation relative to the position of the pressing portion acting at the time of one rotation of the internal gear is S (serration pitch). ) × 1/2 + L (predetermined amount), the displacement amount of the position of the pressing portion acting at the next rotation relative to the position of the pressing portion acting at the next rotation of the internal gear is S (serration pitch) × It is desirable to set to 1 / 2-L (predetermined amount).
In this case, the position of the pressing portion of the temporary serration that acts as if it exists in the middle of the actual serration pitch is in the center of the serration pitch, and the left and right portions in the tooth trace direction are in good balance. Can be processed.

  As described above, according to the present invention, it is possible to reduce the influence of waviness generated on the tooth surface while increasing the processing surface pressure on the internal gear.

It is a perspective view of a part of rolling die 1 of one embodiment of the present invention. It is a figure which shows the tooth | gear of the rolling die shown in FIG. It is a figure which shows the case where it processes by rolling the rolling die shown in FIG. 1, and the internal gear 10 to be processed. It is explanatory drawing which showed the arrangement | sequence of the serration in each tooth of the rolling die shown in FIG. 1 in the order lined up in the circumferential direction. It is explanatory drawing which showed the arrangement | sequence of the serration in each tooth | gear of the rolling die shown in FIG. 1 in order which acts on one tooth | gear B1 of an internal gear. (A) is a figure which shows the tooth surface of one tooth | gear B1 of the internal gear processed by the rolling die shown in FIG. (B) is a figure which shows the tooth surface of one tooth | gear of the internal gear processed by the conventional rolling die. It is a figure which shows the tooth trace shape of the to-be-cut gear by the Example of this invention, (a) has shown the left tooth surface, (b) has each shown the right tooth surface. It is a figure which shows the tooth trace shape of the to-be-cut gear by a comparative example, (a) has shown the left tooth surface, (b) has each shown the right tooth surface.

1 to 5 show an embodiment of the present invention. 1 is a perspective view of a part of a rolling die 1 according to an embodiment of the present invention, FIG. 2 is a view showing teeth of the rolling die shown in FIG. 1, and FIG. 3 is a rolling die shown in FIG. It is a figure which shows the case where it engages with the internal gear 10 and processes.
As shown in FIG. 1, the rolling die 1 of the present embodiment has a substantially disc shape, and a plurality of teeth 2 are provided at equal intervals on the outer periphery thereof, as shown in FIG. Serrations 4 having a plurality of grooves 3 are formed at regular intervals in the direction of the tooth trace (left and right direction in FIG. 2). A peak portion formed between the groove portions 3 is a land 5, and the land 5 is a pressing portion that mainly presses the internal gear 10 that is a processing target.

  As shown in FIG. 3, such a rolling die 1 is formed in a state where the rotational axis O and the rotational axis C of the internal gear 10 to be processed are parallel to each other and separated by a certain distance. The teeth 2 and the teeth 11 of the internal gear are engaged with each other, and the rolling die 1 is rotated about the rotation axis O, whereby the internal gear 10 serving as a gear is driven to rotate, and the tooth surface of the teeth 11 of the internal gear 10 is rotated. Finish processing.

Here, in the rolling die 1 according to the present embodiment, the teeth 2 have, for example, 23 teeth of A1 to A23, while the internal gear to be processed by the rolling die 1 is processed. 10, the tooth 11 is to have 50 sheets number of teeth of B1～B50. FIG. 4 shows an arrangement of the serrations 4 in the order in which the teeth 2 of the rolling die 1 according to this embodiment are provided in the circumferential direction. As shown in FIG. The positions of the serrations 4 of the respective teeth 2 are shifted little by little in the direction of the streak in the order in which they are arranged, so that a differential serration is configured.

  FIG. 5 shows the rolling die 1 in which the serrations 4 are arranged in the order in which they act on one tooth 11 of the internal gear 10. For example, as shown in FIG. 3, when the internal gear rotates once (n = 1) from the state in which the tooth A1 of the rolling die 1 and the tooth B1 of the internal gear 10 mesh (n = 0 rotation), the rolling die The first tooth A5 acts on B1 of the internal gear 10, and the same applies to the tooth B1 in the order of the teeth A9, A13, A17,.

  And in the rolling die 1 of this embodiment, as shown in FIG. 5, about one tooth | gear (for example, tooth | gear B1) of the internal gear 10, at the time of one rotation of the internal gear 10 (for example, n = 0 rotation). The deviation direction of the position of the land 5 of the tooth A5 acting at the time of the next rotation (for example, n + 1 = 0 + 1 = 1 rotation) with respect to the position of the land 5 of the tooth A1 of the rolling die 1 acting on Deviation of the position of the land 5 of the tooth A9 acting at the next rotation (n + 2 = 0 + 2 = 2 rotation) with respect to the position of the land 5 of the tooth A5 acting at the next rotation (n + 1 = 0 + 1 = 1 rotation) The direction is reversed. Hereinafter, every time the internal gear 10 rotates, the displacement direction of the land 5 during the previous rotation and the displacement direction of the land 5 during the rotation are reversed.

  Specifically, with respect to one tooth of the internal gear 10, the position of the land 5 of the tooth A5 acting at the next rotation relative to the position of the land 5 of the tooth A1 of the rolling die 1 acting at the time of one rotation of the internal gear 10. The deviation amount Ga is S (serration pitch) × 1/2 + L (predetermined amount), which acts at the time of the next rotation with respect to the position of the land 5 of the tooth A5 of the rolling die 1 that acts at the time of the next rotation of the internal gear 10. The deviation amount Gb of the position of the land 5 of the tooth A9 is set to S (serration pitch) × 1 / 2−L (predetermined amount). Hereinafter, every time the internal gear 10 rotates, the displacement direction of the land 5 during the previous rotation and the displacement direction of the land 5 during the rotation are reversed, and the displacements are alternately different. The teeth of the rolling die 1 come into contact with one tooth of the internal gear 10 so as to have the quantities Ga and Gb. That is, in this rolling die, the forward and backward movements of one tooth (for example, tooth B1) of the internal gear 10 are sequentially repeated alternately for each rotation of the internal gear 10 by a value of S (serration pitch) × ½. However, the predetermined value L is advanced forward in the processing direction.

  Here, the S (serration pitch) is preferably set to 2.0 to 3.5 mm, and is set to about 3 mm in the present embodiment, for example. This value S (serration pitch) is a larger value than in the case of the shaving cutter. The width w of the land 5 is also preferably set to 0.8 to 1.2 mm, which is a larger value than in the case of the shaving cutter, and is set to, for example, about 1 mm in this embodiment.

  The L (predetermined value) is preferably set to 0.05 to 0.5 mm. This is determined from an empirical rule. If L is smaller than 0.05 mm, it takes too much time to finish the tooth surface corresponding to the serration pitch, resulting in a problem that the production efficiency is lowered. If it is larger than 0.5 mm, the processing amount is too large and the accuracy is lowered.

  The tooth surface of one tooth 11 (B1) of the internal gear 10 processed by the rolling die 1 is processed by each tooth 2 (A1, A5, A9, A13, A17,...) Of the rolling die 1. The portion to be processed is shown as it is in FIG. However, in FIG. 6A, it is assumed that the processing is performed in a state where the tooth A1 is first meshed with the tooth B1. FIG. 6B shows a tooth surface when an internal gear is processed by a die as shown in Patent Document 1 of the related art.

Further, the rolling die of the present embodiment does not have a drill hole formed in the tooth base, and therefore is stronger in strength. In other words, in this type of die, when forming the groove 3 on the surface of the tooth 2, it is usual to form a drill hole in advance on the left and right sides of the tooth base so that the tip of the groove forming tool does not interfere. However, if a drill hole is formed, the strength is weakened accordingly.
Further, in the rolling die of this embodiment, the cutting die is not subjected to cutting, and the rolling die is pressed by pressing the teeth of the rolling die against the teeth of the internal gear with a predetermined pressure. A so-called tooth-killing is done with Earl. This is to prevent the tooth 11 of the internal gear 10 from being damaged by the edge portion of the tooth.

According to the above rolling die or internal gear machining method, since the serration 4 is provided on the tooth surface, the machining surface pressure is increased as compared with the case of machining using a solid tooth surface without the serration 4. Processing becomes easy.
Further, as shown in FIG. 5, the displacement direction of the position of the serration land 5 is alternately reversed every time the internal gear 10 (internal gear) rotates. It acts as if there is a land 5 of another serration in the middle of the serration pitch S (see FIG. 6A). For this reason, the undulation generated on the tooth surface of the internal gear 10 has a shorter cycle than the actual serration pitch S, and the machining margin error at that time can be reduced.

  In the present embodiment, the deviation amount of the position of the land 5 acting at the next rotation relative to the position of the land 5 of the rolling die 1 acting at the time of one rotation of the internal gear 10 is S (serration pitch) × 1 /. 2 + L (predetermined amount), the displacement amount of the land position acting at the next rotation relative to the land position acting at the next rotation of the internal gear 10 is S (serration pitch) × 1 / 2−L ( Therefore, the position of the land of the temporary serration that acts as if it exists in the middle of the actual serration pitch S exists in the center of the serration pitch S, and the tooth trace direction The left and right parts can be processed with good balance.

  In the rolling die 1 of the present embodiment, the internal gear is machined while the direction of the land 5 shifting in the serrations 4 of the plurality of teeth 2 is alternately changed every time the internal gear rotates. The specific deviation amount does not need to be set to Ga and Gb as shown in the embodiment, and can be set appropriately.

  Embodiments of the present invention will be described below with reference to FIGS. FIG. 7 shows the measurement of the tooth shape of each tooth of the internal gear finished by a rolling die as an example of the present invention based on the above-described embodiment, and FIG. 8 shows Patent Document 1 as a comparative example. The inner surface is finished with a rolling die as shown in (In Patent Document 1, a shaving cutter is used, but the tip of the cutting blade is rounded to kill the blade and used as a rolling die) The tooth trace shape of each tooth of the gear is measured, and in each case, (a) row shows the left tooth surface, and (b) row shows the right tooth surface.

  Here, the specifications of the internal gear are module 1.34, pressure angle 19.0 °, torsion angle 21.59 °, number of teeth 76, basic circle 102.834 mm, tooth width 19.4 mm. The specifications of both the example and comparative example are module 1.34, pressure angle 19.0 °, torsion angle 21.59 °, number of teeth 58, basic circle 78.478 mm, tooth width 26 mm, serration pitch 3.0 mm, The land width is 1.00 mm, and in the comparative example, the deviation direction of the position of the cutting blade acting on one tooth of the internal gear is all directed in the same direction for each rotation of the internal gear. As shown in FIG. 5, the left and right are alternately reversed every time the internal gear rotates. At this time, since the serration pitch S was set to 3.00 mm and the predetermined value L was set to 0.26, Ga was 1.76 mm and Gb was 1.24 mm. Then, the rolling dies of the example and the comparative example are respectively meshed with the internal gear at an axis crossing angle of 0 °, the cutter rotation speed is 200 rpm, the plunge feed is 0.0005 mm / rev, and the dwell time is 0.1 min. Rolling processing was performed.

  From the results of FIG. 7 and FIG. 8, the internal gear finished by the rolling die of the comparative example has a large waviness in the tooth shape on both the left and right tooth surfaces, and exhibits periodic fluctuations in the waviness. I understand. On the other hand, in the internal gear using the rolling die of the embodiment, the undulation of the tooth trace shape itself is small, and the periodic undulation of the tooth trace error is suppressed to be small.

  DESCRIPTION OF SYMBOLS 1 ... Rolling die 2, A1-A23 ... Teeth of rolling die 3 ... Groove 4 ... Serration 5 ... Land (pressing part) 10 ... Internal gear 11, B1-B50 ... Teeth of work gear

Claims (5)

In a rolling die for machining an internal gear that has a plurality of teeth with serrations on the tooth surface, and the position of the pressing portion of the serrations is sequentially shifted in the direction of the tooth trace to be differential serrations,
With respect to one tooth of the internal gear to be processed, the displacement direction of the position of the pressing portion acting at the next rotation relative to the position of the pressing portion acting at the time of rotation of the internal gear, and the next of the internal gear A rolling die characterized in that the direction of displacement of the position of the pressing portion acting at the next rotation is opposite to the position of the pressing portion acting at the time of rotation.   With respect to one tooth of the internal gear to be processed, the displacement amount of the position of the pressing portion acting at the next rotation relative to the position of the pressing portion acting at the time of one rotation of the internal gear is S (serration pitch) × 1. / 2 + L (predetermined amount), the displacement amount of the position of the pressing portion acting at the next rotation relative to the position of the pressing portion acting at the next rotation of the internal gear is S (serration pitch) × 1/2 The rolling die according to claim 1, which is set to -L (predetermined amount).   The rolling die according to claim 2, wherein the S (serration pitch) is set to 2.0 to 3.5 mm.   The rolling die according to claim 2 or 3, wherein the L (predetermined value) is set to 0.05 to 0.5 mm. An internal gear machining method for machining an internal gear using the rolling die according to claim 1,
With respect to one tooth of the internal gear, the displacement direction of the position of the pressing portion acting at the time of the next rotation relative to the position of the pressing portion acting at the time of the rotation of the internal gear, and at the time of the next rotation of the internal gear The direction of displacement of the position of the pressing portion acting at the time of the next rotation with respect to the position of the pressing portion that acts is reversed, and hereinafter, the direction of displacement of the pressing portion is alternately reversed every time the internal gear rotates. The internal gear machining method, characterized in that the internal gear is machined while being changed.

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