JP6455704B2 - Helical internal gear forming method and helical internal gear forming apparatus - Google Patents

Description

  The present invention relates to a helical pinion cutter used for pinion gear cutting.

  As a method of forming an internal gear, pinion gear cutting using a pinion cutter is known (for example, Patent Document 1).

  Further, plug hardening is known as a method for correcting distortion such as elliptical deformation generated by intermediate heat treatment such as carburizing for a thin ring-shaped internal gear component (for example, Patent Document 2).

JP 2004-160645 A Japanese Examined Patent Publication No. 4-61727

  In the plug quenching, distortion is corrected based on the inner diameter (small diameter) which is the diameter of the tip of the internal gear. For this reason, if the processing accuracy of the small diameter of the internal gear by pinion gear cutting is low, the effectiveness of correction by plug quenching is impaired.

  In a spur pinion cutter used in pinion gear cutting of a spur internal gear, each blade of the cutter tooth bottom directly forms a tooth tip (small diameter) of the internal gear. For this reason, by increasing the accuracy of each blade of the cutter tooth bottom, it is possible to increase the processing accuracy of the small diameter of the internal gear, and it is possible to correct distortion such as elliptical deformation by plug quenching based on the small diameter. .

  On the other hand, in the helical pinion cutter used in the pinion gear cutting of the helical gear, there is a step in the cutter tooth bottom (between two adjacent blades), and each blade of the helical pinion cutter is The tooth tip is not formed directly. For this reason, it is difficult to increase the processing accuracy of the small diameter of the internal gear, and the effectiveness of correction by plug quenching may be impaired.

Accordingly, an object of the present invention is to provide a helical internal gear forming method and a helical internal gear forming apparatus capable of improving the processing accuracy of a small diameter of a helical internal gear formed by pinion gear cutting. .

In order to achieve the above object, the present invention provides a helical internal gear forming method or a helical internal gear in which a helical internal gear is formed on the inner peripheral surface of a workpiece by pinion gear cutting using a helical pinion cutter . In the gear forming device, the helical pinion cutter includes a tooth surface forming cutter and a tooth tip finishing cutter. The tooth surface forming cutter has a plurality of blades arranged in the circumferential direction with the first rotation axis as a center, and advances in the processing direction while rotating about the first rotation axis, so that the object to be processed is A tooth surface of an internal gear is formed on the inner peripheral surface. The tooth tip finishing cutter has an annular blade centered on the first rotation axis, and is arranged on the rear side in the processing direction of the tooth surface forming cutter and rotates integrally with the tooth surface forming cutter to form a tooth surface. The tooth tip of the helical internal gear formed by the cutter is cut.
The distance from the blade of the tooth finish cutter to the first rotation axis is longer than the distance from the cutter tooth bottom to the first rotation axis between two adjacent blades in the circumferential direction of the tooth surface forming cutter, and the tooth It is shorter than the distance from the blade of the surface forming cutter to the first rotation axis. One stroke that rotates the helical pinion cutter around the first rotation axis, rotates the object to be processed around the second rotation axis, moves the helical pinion cutter forward in the machining direction, and then retracts it back in the counter machining direction. Are repeated for a plurality of strokes, and the distance from the second rotation axis to the first rotation axis during the forward movement of the helical pinion cutter is gradually increased between the strokes.

In the above method and apparatus , after the tooth surface of the internal gear is formed by the pre-processing by the tooth surface forming cutter, the tooth tip (tip of the tooth surface) formed by the pre-processing is post-processed by the tooth tip finishing cutter. Is cut by.

  There is a step in the tooth bottom of the tooth surface forming cutter corresponding to the tooth tip of the helical gear, and the tooth tip of the helical gear is not directly formed by the blade of the tooth surface forming cutter. For this reason, when forming an internal gear using a helical pinion cutter that does not have the above-mentioned tooth tip finishing cutter, it is necessary to form the inner diameter (small diameter), which is the diameter of the tip circle, in a separate process by a small diameter processing cutter. There is. In this case, since the pitch circle of the helical gear (the helical gear reference pitch circle) and the tip diameter (small diameter) are processed in separate processes, the helical gear reference pitch circle and the small diameter It is difficult to ensure the coaxial position accuracy.

  On the other hand, in the above-described configuration, the diameter of the tooth tip finishing cutter (small diameter processing cutter) is set to be equal to or larger than the diameter of the coaxial bottom portion of the tooth surface forming cutter, and the tooth surface and the small diameter of the helical gear. Are cut in the same process. Accordingly, it is possible to improve the coaxial positional accuracy between the pitch circle and the small diameter of the helical gear.

  Further, since the tooth tip finishing cutter rotates integrally with the tooth surface forming cutter, the pre-processing by the tooth surface forming cutter and the post-processing by the tooth tip finishing cutter can be collectively performed as a series of processes.

  According to the present invention, it is possible to improve the processing accuracy of a small diameter of a helical gear formed by pinion gear cutting.

It is an external appearance perspective view of the helical pinion cutter which concerns on one Embodiment of this invention. It is sectional drawing of the helical pinion cutter of FIG. It is the principal part enlarged view of a tooth surface formation cutter, (a) is an expansion perspective view which shows the IIIa part of FIG. 1, (b) is the enlarged view seen from the arrow IIIb direction of FIG. It is a perspective view for demonstrating pinion gear cutting using the helical pinion cutter of FIG.

  Hereinafter, a helical pinion cutter 1 according to an embodiment of the present invention will be described with reference to the drawings. In the following description, the front side in the processing direction of the helical pinion cutter 1 is set as the lower side, and the rear side is set as the upper side.

  As shown in FIGS. 1 to 4, the helical pinion cutter 1 includes a disc-shaped mounting plate portion 2, a cylindrical peripheral wall portion 3, an annular tooth surface forming cutter 4, and a tooth tip finishing cutter 5. It is attached to the end face of the gear shaper 21 that rotates around the rotation shaft 20.

  A cylindrical positioning projection 22 is provided on the lower end surface of the gear shaper 21 so as to be coaxial with the rotary shaft 20, and a bolt portion 23 is provided on the lower end surface of the positioning projection 22 so as to extend downward coaxially with the rotary shaft 20.

A circular positioning hole 6 having an inner diameter slightly larger than the outer diameter of the positioning projection 22 of the gear shaper 21 is formed in the center of the mounting plate portion 2 of the helical pinion cutter 1. By inserting the positioning engagement portion 22 into the positioning engagement hole 6 from below, the helical pinion cutter 1 is positioned with respect to the gear shaper 21, and the center of the mounting plate portion 2 substantially coincides with the rotating shaft 20. The bolt portion 23 extends from the lower end surface of the positioning projection 22 inserted into the positioning engagement hole 6 to the outside of the positioning hole 6, and a nut 24 is screwed into the tip end portion of the bolt portion 23 from below, whereby a helical pinion cutter 1 is fastened and fixed (attached) to the lower end surface of the gear shaper 21. The mounted helical pinion cutter 1 rotates integrally with the gear shaper 21 around the rotation shaft 20.

  The peripheral wall portion 3 bends downward from the outer peripheral edge of the mounting plate portion 2 and extends while being inclined so as to increase the diameter downward.

The tooth surface forming cutter 4 is provided on the outer peripheral surface of the lower portion of the peripheral wall portion 3 and advances in the processing direction while performing a combined movement of rotation about the rotation shaft 20 and tilting (rotation) of the rotation shaft 20. Thus, the tooth surface of the internal gear 31 is formed on the inner peripheral surface of the internal gear component (processing object) 30. The tooth surface forming cutter 4 has a plurality of blades 7, and the plurality of blades 7 are arranged at regular intervals along the circumferential direction around the rotation shaft 20. The plurality of blades 7 extend in the vertical direction so as to be inclined with respect to the rotation shaft 20, and protrude from the outer peripheral surface of the peripheral wall portion 3. A step 8 exists between the two blades 7 adjacent in the circumferential direction on the lower end surface of the tooth surface forming cutter 4 (the cutter tooth bottom corresponding to the tooth tip 32 of the formed internal gear 31). (See FIGS. 3A and 3B). For this reason, the tooth tip 32 of the helical gear 31 is not directly formed by the blade 7 of the tooth surface forming cutter 4 .

The tooth end finishing cutter 5 is a so-called round blade, and is provided on the outer peripheral surface of the upper portion of the peripheral wall portion 3 so as to be separated from the tooth surface forming cutter 4 . The tooth tip finishing cutter 5 has an annular blade 9 protruding from the outer peripheral surface of the peripheral wall 3, and the distance (radius) R <b> 2 from the rotary shaft 20 to the blade 9 of the tooth tip finishing cutter 5 is from the rotary shaft 20 to the tooth. The distance (radius) R1 to the step 8 of the surface forming cutter 4 is set to be equal to or greater than R1. The blade 9 of the tooth end finishing cutter 5 cuts the tip of the tooth tip 32 of the helical internal gear 31 formed by the tooth surface forming cutter 4 by advancing in the processing direction while rotating about the rotating shaft 20. .

  Next, a method of forming the internal gear 31 on the inner peripheral surface of the thin ring-shaped internal gear component 30 by pinion gear cutting using the helical pinion cutter 1 of the present embodiment will be described. The internal gear component 30 is supported by a work support portion (not shown) so as to be rotatable about the rotation shaft 33 (vertical direction in the present embodiment).

When forming the helical gear 31, the helical pinion cutter 1 is mounted on the lower end surface of the gear shaper 21 to rotate the internal gear component 30, and the gear shaper 21 (helical pinion cutter 1) rotates synchronously with the internal gear component 30. while is lowered to towards the helical pinion cutter 1 with the internal gear part 30 of the lower axial (direction along the rotation axis 3 3). The gear shaper 21 rotates about the rotating shaft 20 and moves (lowers) in the machining direction while tilting (rotating) with respect to the rotating shaft 33 of the internal gear part 30.

The helical pinion cutter 1 is rotated from the rotary shaft 33 of the internal gear component 30 so that the tooth surface of the internal gear 31 is gradually formed by the tooth surface forming cutter 4 (so that the tooth gap is gradually deepened). The helical pinion cutter 1 is repeatedly lowered with respect to the internal gear part 30 a plurality of times while gradually increasing the distance to the rotary shaft 20 between strokes. That is, when a single stroke to lower the helical pinion cutter 1 in the axial direction from the machining start height above the internal gear part 30 to the processing end height position of the lower ends, the machining start high a helical pinion cutter 1 to the is returned to the position, distance from the rotation shaft 33 to the rotational shaft 20 so that movement in the radial direction orthogonal to the rotation axis 3 3 gear shaper 21 to increase the predetermined amount, the processing of the next stroke (downward in helical pinion cutter 1 ) And the descent of the helical pinion cutter 1 is repeated until the number of strokes reaches a predetermined number of times (until the distance from the rotary shaft 33 to the rotary shaft 20 reaches a predetermined distance). Further, in each stroke, in accordance with the inclination of the teeth of the helical internal gear 31 relative to the axis of rotation 3 3, is changed according to the inclination angle of the rotary shaft 20 with respect to the rotation shaft 3 3 a lowering amount of the helical pinion cutter 1 .

In each stroke, when the helical pinion cutter 1 is lowered, first, the blade 7 of the tooth surface forming cutter 4 comes into contact with the internal gear component 30, and the tooth surface of the internal gear 31 is placed on the inner peripheral surface of the internal gear component 30. Form. In other words, the tooth surface of the helical gear 31 is gradually formed from the upper end side to the lower end side of the inner peripheral surface of the internal gear component 30 by the pre-processing by the tooth surface forming cutter 4 .

When the pre-processing advances and the tooth surface forming cutter 4 moves downward from the upper end of the internal gear part 30 and the blade 9 of the tooth tip finishing cutter 5 reaches the upper end of the internal gear part 30, it is formed by the pre-processing. and addendum 3 blades 9 of the second tip tooth finishing cutter 5 is cut. As the helical pinion cutter 1 descends, the region in which the tooth tip 32 is cut by post-processing by the tooth tip finishing cutter 5 increases from the upper end side to the lower end side of the inner peripheral surface of the internal gear part 30, and the tooth tip finishes. When the cutter 5 moves downward from the lower end of the internal gear part 30, the pre-processing and post-processing of one stroke with respect to the entire inner peripheral surface of the internal gear part 30 is completed, and the number of strokes reaches a predetermined number. Thus, the formation of the helical gear 31 is completed. In addition, in the stroke of the first half of the machining in which the tooth tip 32 is not formed by the pre-machining, the tooth tip finishing cutter 5 does not contact the internal gear part 30 and the post-machining is not executed. On the other hand, post-processing by the tooth-end finishing cutter 5 is executed in the later-stage stroke (particularly the final stroke) in which the tooth tip 32 is formed by the pre-processing. Further, lowering in each stroke, after the pre-processing is completed, without tilting the rotational shaft 20 to the rotation axis 3 3, a helical pinion cutter 1 while maintaining the rotation axis 20 substantially parallel to the rotary shaft 3 3 You may let them.

  According to the helical pinion cutter 1 of the present embodiment, after the tooth surface of the internal gear 31 is formed by the pre-processing by the tooth surface forming cutter 4, the tooth tip 32 formed by the pre-processing is the tooth tip finishing cutter. It is cut by post-processing according to 5.

  A step 8 exists on the cutter tooth bottom of the tooth surface forming cutter 4, and the tooth tip 32 of the helical internal gear 31 is not directly formed by the blade 7 of the tooth surface forming cutter 4. For this reason, when forming an internal gear using a helical pinion cutter that does not have the tooth tip finishing cutter 5, it is necessary to form the inner diameter (small diameter), which is the diameter of the tip circle, in a separate process using a small diameter processing cutter. There is. In this case, since the pitch circle (reference pitch circle) of the helical gear and the diameter of the tip circle (small diameter) are processed in separate processes, the coaxial position of the reference pitch circle and the small diameter of the helical gear 31 is obtained. It is difficult to ensure accuracy.

  On the other hand, in this embodiment, since the tooth tip finishing cutter 5 is arranged on the same axis as the tooth surface forming cutter 4 and the helical gear 31 and the tooth tip 32 are cut in the same process, the helical tooth. The coaxial position accuracy between the pitch circle center and the small diameter center of the internal gear 31 can be ensured. Therefore, the processing accuracy of the small-diameter internal gear 31 can be improved so that the effectiveness of correction of distortion by plug quenching based on the small diameter is not impaired.

  Further, since the tooth tip finishing cutter 5 rotates integrally with the tooth surface forming cutter 4, the pre-processing by the tooth surface forming cutter 4 and the post-processing by the tooth tip finishing cutter 5 can be performed together as a series of processes. .

  Further, since the tooth tip finishing cutter 5 is spaced upward from the tooth surface forming cutter 4, the blade 7 of the tooth surface forming cutter 4 and the blade 9 of the tooth tip finishing cutter 5 can be ground and reused.

  As mentioned above, although the embodiment to which the invention made by the present inventor is applied has been described, the present invention is not limited by the discussion and the drawings that form part of the disclosure of the present invention according to this embodiment. That is, it is needless to say that other embodiments, examples, operation techniques, and the like made by those skilled in the art based on this embodiment are all included in the scope of the present invention.

  For example, instead of the helical pinion cutter 1 having the tooth surface forming cutter 4 and the tooth tip finishing cutter 5 integrally, the tooth surface forming cutter and the tooth tip finishing cutter are formed as separate parts, and both are integrated to form the gear shaper 21. It may be attached to the gear shaper 21 without being integrated with each other.

  The helical pinion cutter of the present invention can be used for pinion gear cutting of various internal gear parts.

DESCRIPTION OF SYMBOLS 1 Helical pinion cutter 4 Tooth surface formation cutter 5 Tooth tip finishing cutter 8 Level difference 20 , 33 Rotating shaft 21 Gear shaper 30 Internal gear component (processing object)
31 helical internal gear 32 addendum

Claims (2)

A helical internal gear forming method for forming a helical internal gear on the inner peripheral surface of the object to be processed by pinion gear cutting using a helical pinion cutter ,
The helical pinion cutter is
A plurality of blades arranged in a circumferential direction with the first rotation axis as a center, and advancing in the machining direction while rotating about the first rotation axis, thereby forming a tooth on the inner peripheral surface A tooth surface forming cutter for forming the tooth surface of the internal gear;
The tooth surface forming cutter has an annular blade centered on the first rotation axis, and is disposed on the rear side in the processing direction of the tooth surface forming cutter and rotates integrally with the tooth surface forming cutter. wherein comprises a tooth tip finishing cutter for cutting the tooth tip of the helical internal gear, a that but formed,
The distance from the blade of the tooth finish cutter to the first rotation axis is the distance from the cutter tooth bottom between the two blades adjacent in the circumferential direction of the tooth surface forming cutter to the first rotation axis. Longer than and shorter than the distance from the blade of the tooth surface forming cutter to the first rotation axis,
The helical pinion cutter is rotated about the first rotation axis, the processing object is rotated about the second rotation axis, and the helical pinion cutter is advanced in the processing direction and then retracted in the counter machining direction. A helical tooth that repeats a plurality of strokes to be returned, and gradually increases the distance from the second rotation axis to the first rotation axis when the helical pinion cutter moves forward. Internal gear forming method . A helical internal gear forming device that forms a helical internal gear on the inner peripheral surface of the object to be processed by pinion gear cutting using a helical pinion cutter,
The helical pinion cutter is
A plurality of blades arranged in a circumferential direction with the first rotation axis as a center, and advancing in the machining direction while rotating about the first rotation axis, thereby forming a tooth on the inner peripheral surface A tooth surface forming cutter for forming the tooth surface of the internal gear;
The tooth surface forming cutter has an annular blade centered on the first rotation axis, and is disposed on the rear side in the processing direction of the tooth surface forming cutter and rotates integrally with the tooth surface forming cutter. A tooth tip finishing cutter for cutting the tooth tip of the helical internal gear formed by
The distance from the blade of the tooth finish cutter to the first rotation axis is the distance from the cutter tooth bottom between the two blades adjacent in the circumferential direction of the tooth surface forming cutter to the first rotation axis. Longer than and shorter than the distance from the blade of the tooth surface forming cutter to the first rotation axis,
The helical pinion cutter is rotated about the first rotation axis, the processing object is rotated about the second rotation axis, and the helical pinion cutter is advanced in the processing direction and then retracted in the counter machining direction. The one stroke to be returned is repeated for a plurality of strokes, and the distance from the second rotation axis to the first rotation axis when the helical pinion cutter moves forward is gradually increased between the strokes.
A helical gear forming apparatus characterized by that.

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