JPH11320411A - Gear peening processing method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the fatigue strength of a deddendum area by letting the addendum of a gear interfer with a interference material, by hitting a peening body at the deddendum area with a tensile stress generated in the deddendum area of the gear, and implementing the shot peening. SOLUTION: A gear 2 is attached to a rotatable spindle 3 and an interference material 4 is so arranged as to interfere with an addendum of the gear 2. The rotation of the spindle 3 rotates the gear 2 to let the addendum of the gear 2 interfere with the interference material 4. This constitution allows the shot peening by hitting a peening body 7 at the deddendum so as to prevent the fracture in the deddendum area of the gear. Even if the peening body moves at low speed, the tensile force is applied thereon so that the fatigue strength can be improved. The deformation of the tooth shape of the gear can be suppressed to the minimum.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a peening treatment method and a peening treatment device, and more particularly to a gear peening treatment method and device for improving the fatigue strength of a gear by shot peening.

[0002]

2. Description of the Related Art Conventionally, shot peening has been used in a wide range of mechanical fields. Conventionally, to perform a peening process on a gear, attach the gear to a rotatable support shaft,
Shot peening is performed by injecting a steel ball, which is a peened body, from the nozzle with compressed air and applying the steel ball to a gear. In the above gear peening method, the residual compression pressure generated by peening depends on the pressure of the air nozzle. Therefore, in order to increase the residual compression pressure, the pressure of the compressed air must be increased.

[0003]

However, the above-mentioned conventional gear peening method has the following problems. (A) If the pressure of the compressed air is increased in order to obtain a high residual compressive stress, there is a problem that the deformation of the tooth profile due to the collision of the peening sphere increases. Therefore, post-processing for correcting the deformation of the tooth profile is required. (B) In the conventional method, the peening sphere collides with the entire gear. Therefore, even if there is a request to particularly improve the strength of a part of the gear as compared with other parts, the strength is locally improved by peening. It was difficult. For example, since a large force is continuously applied to a power transmission gear of a general-purpose engine, high strength and high fatigue durability are required. In such a power transmission gear, since the load is applied in one direction, there is a problem that the root area where the force is applied is easily broken.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a gear peening processing method and a gear peening processing apparatus which can solve the above problems. An example of a specific purpose is as follows. (a) It is possible to intensively perform peening processing on a root area where a force is applied to a gear, and to improve fatigue strength of the root area. (b) Although the fatigue strength can be significantly improved, the amount of tooth profile deformation can be minimized. It should be noted that the problems of the invention other than those described above and the means for solving the problems will be described in detail in the description in the following specification.

[0005]

The present invention will be described below with reference to, for example, FIGS. 1 to 8 showing an embodiment of the present invention. In the first invention, the gear 2 is mounted on a rotatable support shaft 3, an interference object 4 is arranged so as to interfere with the tooth tip of the mounted gear 2, and the rotation of the support shaft 3 causes the gear 2 to rotate. In a state where the tooth tip of the gear 2 and the interfering object 4 interfere with each other and a tensile stress is generated in the tooth root region 6 of the gear 2, shot peening is performed by applying a peening body 7 to the tooth root region 6. Features. The second invention is
Mainly as shown in FIGS. 1 to 4, a support shaft 3 on which the gear 2 is mounted
, An interference object 4 that interferes with the tooth tip of the gear 2, and an interference object arrangement that arranges the interference object 4 so that the tooth tip of the mounted gear 2 and the interference object 4 interfere with each other. It is characterized by comprising a means 5 and a peening body injection means 8 for causing a peening body 7 to collide with a tooth root region 6 to which a tensile stress has been applied due to interference of the interference object 4.

[0006] A third aspect of the present invention is the above peening body injection means 8.
Is provided with a peening body distribution area control means 14 for controlling a distribution area 15 of the peening body 7 so that the peening body 7 collides only with the root area 6. The fourth invention mainly includes a gear rotating means provided with a support shaft 3 on which the gear 2 can be mounted and which can rotate forward and backward, and an interference object 4 which interferes with the tooth tip of the gear 2 as shown in FIG. Interfering object disposing means 5 for disposing the interfering object 4 so that the tooth tip of the mounted gear 2 and the interfering object 4 interfere with each other.
In the state where a tensile stress is generated in the root area 6a of the gear 2 due to interference with the interference object 4 during the forward rotation of the gear,
The first peening body injection parts 8a and 13 for performing shot peening aiming at a and the root area of the gear 2 in a state where a tensile stress is generated in the root area 6b of the gear 2 due to interference with the interfering object 4 during the reverse rotation of the gear. It is characterized by having second peening body emitting parts 8b and 13 for performing shot peening aiming at 6b.

According to a fifth aspect of the present invention, as shown mainly in FIG. 6, a gear 2 is mounted on a rotatable support shaft 3, and an interference object 4 is arranged so as to interfere with the tooth tip of the mounted gear 2. By rotating the gear 2 by the rotation of the support shaft 3, the tooth tip of the gear 2 and the interference object 4 interfere with each other, and a tensile stress is generated in the tooth root area 6 of the gear 2, aiming at the tooth root area 6. After the primary peening step in which shot peening is performed by applying the peened body 7, and after the primary peening step, the peened body 7 having the same size as the peened body 7 is applied in a state where no tensile stress is generated in the same tooth root region 6. And a secondary peening step of performing shot peening.

[0008]

According to the first aspect of the present invention, the tooth tip of the gear and the interfering object are caused to interfere with each other, and a peening body is applied to the tooth root area in a state where a tensile stress is generated in the tooth root area. Since the shot peening is performed, the shot peening can be concentrated on the root area where force is likely to be broken during fatigue, and the root area of the gear can be prevented from breaking. Further, even when the peened body is at a low speed, the tensile stress is applied, so that the fatigue strength can be improved. Further, even if a high level of residual compressive stress is generated to increase the fatigue strength, the deformation of the gear tooth profile can be minimized because the speed of the peening body is low.

According to the second aspect of the present invention, a gear is mounted on the support shaft of the gear rotating means, and the interfering object is disposed so that the tooth tip of the mounted gear and the interfering object interfere with each other by the interfering object disposing means. . Then, the peening body is caused to collide with the root area of the tooth on which the force is applied by the interference of the interfering object by the peening body injection means. According to this gear peening processing apparatus, shot peening can be performed concentrated on the dedendum region that is fragile and easily broken at the time of fatigue, and breakage of the dedendum region of the gear can be prevented. Further, even if the peening body is at a low speed, a tensile stress is applied, so that a desired fatigue strength can be obtained. Further, even if a high level of residual compressive stress is generated to increase the fatigue strength, the deformation of the gear tooth profile can be minimized because the speed of the peening body is low.

According to the third aspect of the present invention, since the peening body injection means includes the peening body distribution area control means,
The distribution area of the peening body can be controlled so that the peening body collides only with the tooth root area, and the peening body can collide with the tooth tip and other parts of the gear that do not need to particularly improve the fatigue strength. Disappears. Further, when the gear has a small diameter, the distance between the root area and the tooth tip is short, but by providing the peening body distribution area control means, even if the gear is such a small gear, It is possible to cause the peening body to collide with only the original region.

According to the fourth aspect of the present invention, the gear is mounted on the support shaft of the gear rotating means which is rotatable forward and backward, and the interference between the tooth tip of the mounted gear and the interfering object by the interfering object disposing means is provided. Arrange interference. Then, the spindle of the gear rotating means is rotated forward, and a shot is aimed at the tooth root area in a state where a tensile stress is generated in the tooth root area of the gear due to interference with the interfering object by the first peening body injection part. Perform peening. Thereafter, the support shaft of the gear rotating means is reversed, and shot peening is performed with the second peening body injection section aiming at the tooth root area in a state where tensile stress is generated in the tooth root area.

According to the fourth aspect of the present invention, since the first peening body emitting section aiming at the root area at the time of normal rotation and the second peening body emitting section aiming at the root area at the time of reverse rotation are provided in advance, the tooth is provided. In the case of peening the root area on both sides of the gear, it is only necessary to switch the normal rotation and the reverse rotation of the gear and eject the peening body from the corresponding peening body ejection part. Therefore, when peening the root area on both sides of the tooth, there is an advantage that the extra work of once removing the gear from the support shaft and changing the front and rear sides can be omitted. According to the fifth aspect, by applying a high residual stress to the tooth root area surface layer of the gear with a high peening effect by the primary peening step, and then applying a low residual stress to the tooth root area surface layer by the secondary peening step. It is possible to obtain the same effect as double shot peening in which peening is performed with two types of peening bodies having different sizes and sizes. Also, primary peening process,
Since both of the secondary peening steps are performed by using peened bodies of the same size, there is an advantage that the subsequent peening body sorting process becomes unnecessary and maintenance is simplified.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a gear peening method of the present invention;
Schematic configuration diagram for explaining a gear peening processing device,
FIG. 2A is a perspective view showing a tooth root region of the gear, and FIG. 2B is a perspective view showing an example of an injection unit of the peening ball injection device. The gear peening apparatus 1 includes a gear rotating device (not shown) having a rotatable support shaft 3 on which a gear 2 is mounted.
And an interfering object 4 that interferes with the tooth tip of the gear 2 and an interfering object that arranges the interfering object while adjusting the distance, angle, and the like so that the interfering object 4 interferes with the tooth tip of the mounted gear 2. A peening sphere ejecting device 8 for ejecting a peening sphere 7 by aiming at a root area 6 of a tooth to which a force is exerted by interference of the interference object 4 with the device 5
And

In the gear rotating device, a plurality of gears 2 can be mounted by inserting the support shaft 3 into the boss 2a of the gear 2. The support shaft 3 of the gear rotating device is configured to be rotatable in at least one direction. Interference 4
It is preferable that the elastic member has strength and elasticity capable of generating a tensile stress in the root region 6 of the gear 2. In this embodiment, it is constituted by a steel plate 9 which can be returned to its original state by elasticity. The interfering object arranging device 4 is a device that fixes the interfering object 4 at a position where the interfering object 4 can be brought into contact with the tooth tip 37 of the gear 2. The peening sphere injection device 8
A device for aiming and injecting into the tooth root region 6 subjected to tensile stress, the injection method is not particularly limited, and one using compressed air, one using centrifugal force, other known methods, etc. Can be illustrated.

It is preferable that the peening sphere injection device 8 includes direction control means 10 for controlling the direction in which the peening sphere 7 is emitted. The peening sphere injection device 8 moves vertically (Z
Attached to a table 11 that can move in the axial direction), left and right (X-axis direction), and front-rear direction (Y-axis direction), a base 12 that is rotatable around the X axis is attached to the table 11. Further, the base 12 is provided with a peening ball injection device 8.
Is provided. Therefore,
By adjusting the three-dimensional position of the table 11 and rotating the peening sphere emitting unit 13 in a predetermined direction, the direction of the peening sphere 7 to be emitted can be accurately directed to the root area 6. Note that, as the direction control means 10, a configuration of a conventionally known peening sphere injection device can be adopted.

The peening sphere injection device 8 controls the distribution area of the peening sphere 7 so that the peening sphere 7 collides only with the tooth root area 6.
4 is preferably provided. The peening sphere distribution area control means 14 controls the peening sphere 7 as shown in FIG.
Of the peening sphere distribution area 15 where
There is no particular limitation as long as it is controlled to. Such means include a nozzle tip 16 that can obtain the peening sphere distribution area 15 as shown in FIG.
Can be exemplified. In addition, in the conventional peening sphere injection device, as shown in FIG. 3A, the peening sphere distribution region 15 in which the peening sphere collides with a wide range is obtained. A peening sphere distribution area 15 in which the peening spheres concentrate and collide with a narrow width area s as shown in FIG.

FIG. 4 shows a guide member 21 as a peening sphere distribution area control means 14 in an air blowing type injection device 20 having a peening sphere supply pipe 18 and an air blowing pipe 19.
FIG. 3 is a diagram showing a configuration provided with. The guide member 21 is a member that controls the spread width of the discharged peening sphere 7, and by the action of the guide member 21, the spread width d after the control is made smaller than the spread width D without the guide member 21. Can be squeezed. Therefore, even with a small gear, the peening sphere 7 can collide with the root area in a desired distribution range. The interfering object arranging device 5 shown in FIG.
2 and an operation arm 23 that can raise and lower the grip 22. Operation arm 23 as required
Is a table 1 movable in three orthogonal directions as described above.
1 may be used. In addition, a buffer layer 24 for protecting the tooth tip is fixed to the contact surface of the steel plate 9 in contact with the tooth tip.

The operation of the gear peening apparatus will be described. In FIG. 1, first, a support shaft 3 of a gear rotating device is provided.
A plurality of gears 2 are fixed, and the direction of the nozzle tip 16 of the peening sphere injection device 8 is set at a predetermined tooth position of the gear 2 at the root area 6 thereof. Further, the interfering object 4 is fixed to the interfering object disposition device 5, and the interfering object disposing device 5 is operated to position the interfering object 4 at the predetermined tooth position so that the interfering object 4 interferes with the tooth tip. I do.

Thereafter, the gear 2 is rotated by rotating the support shaft 3 of the gear rotating device. The rotation of the gear 2 causes the interference 4
Indicates the arrow 25 on the tooth because of interference with the tooth tip at the predetermined tooth position.
The force indicated by. At this time, a tensile stress is generated in the root region 6 of the tooth, and the peening sphere 7 is caused to collide with a portion where the tensile stress is generated. By causing the peening sphere 7 to collide with the place where the tensile stress is generated, a low peening collision pressure can be obtained.
A high residual compressive stress can be generated, and the root area 6 that is easily broken can be intensively strengthened. And
The teeth of the gear are successively located at the predetermined tooth positions, and the teeth of the gear 2 can be strengthened in the direction in which the force is applied by sequentially colliding the peening balls 7 with the root areas of the teeth. In the above operation, the gear 2 is continuously rotating, and the peening sphere 7 of the peening sphere injection device 8 is continuously emitting. The interfering object 4 is fixed at a position where the interfering object 4 interferes with the tooth tip. The interfering tooth tip deforms the interfering object 4 by the elasticity of the interfering object 4 and pushes the interfering object 4 to rotate.

[0020]

Second Embodiment FIG. 5 is a schematic configuration diagram showing a second embodiment of the present invention. The features of the second embodiment as compared with the first embodiment are as follows. First, FIG.
As shown in (A), the position where the gear 2 interferes with the tooth tip is determined, and the peening sphere injection devices 8a and 8b are provided on both sides of the interference object 4 at the interference position. Then, as shown in FIG. 5 (B), when the gear 2 rotates forward while interfering with the interfering object 4, the first peening sphere injection device 8a is capable of peening the root area 6a on one side of the tooth. When the first peening ball injection device 8a is positioned and the gear 2 reverses while interfering with the interfering object 4 as shown in FIG. The second peening sphere injection device 8b is positioned so as to peening the original region 6b. The first peening sphere injection device 8a and the second peening sphere injection device 8b are not limited to one and only one (two in total), but may be plural, for example, three and three. It may be provided.

Further, only one peening sphere emitting device is provided, and only the peening sphere emitting portion 13 is positioned at the time of forward rotation and reverse rotation of the first peening sphere emitting device 8a in FIGS. 5B and 5C. And the position of the second peening sphere injection device 8b. With this configuration, the first
In addition to the effects of the present embodiment, both sides of the gear teeth can be peened only by rotating the gear forward and backward, and the peening process can be performed more efficiently when the gear is subjected to a large force not only in one direction but also in both directions.

[0022]

Third Embodiment FIG. 6 is a schematic configuration diagram showing a third embodiment of the present invention. In the third embodiment, the mounted gear 2
An interfering object 4 is disposed so as to interfere with the tooth tip of the gear 2, and the interlocking object 4 generates a tensile stress in the root area 6 of the gear 2 by the rotation of the support shaft 3. After a primary peening step of performing shot peening, a secondary peening step of performing peening again while aiming at the root area 6 with the tensile stress released is performed. For example, the primary peening sphere injection device 26 and the secondary peening sphere injection device 27 in FIG. 6 are arranged so as to aim at the root area 6 of the same tooth 38, and the primary peening sphere injection device 26
The peening sphere 7 ejected from the surface hits the dedendum region 6 under a tensile stress, and the peening sphere 7 ejected from the secondary peening sphere injection device 27 hits the dedendum region 6 immediately after the tensile stress is released. Each timing is set. Further, the same effect can be obtained even if the secondary peening sphere injection device 27 is provided at the position 28 which aims at the root region 6 of the same tooth after rotating the predetermined angle.

As described above, by applying a high residual stress to the root region surface layer of the gear 2 by the primary peening step and applying a low residual stress to the root region surface layer by the secondary peening step, it is as if An effect equivalent to double shot peening in which peening is performed first with a large peening sphere and then peening with a small peening sphere can be obtained. FIG. 7 is a diagram for explaining the effect of the present embodiment, in which the horizontal axis represents the depth of the tooth root region surface layer, and the vertical axis represents the residual compressive stress obtained by peening.

By the primary peening step, a residual compressive stress curve 30 as shown in FIG. 7A is obtained. In this state, the residual compressive stress 30 is not sufficiently obtained in the shallow region L of the root region surface layer. From this state, a relatively lower residual compressive stress is applied to the same root region by the secondary peening step than in the primary peening step, so that the shallow region L of the root region surface layer as shown by the solid line in FIG. In this case, a residual compressive stress curve 31 having a sufficient residual compressive stress can be obtained. In the second embodiment, it is possible to use peening spheres of the same size in both the primary peening step and the secondary peening step. In that case, compared to conventional double shot peening using peening spheres of multiple diameters, sorting work for each diameter after collection of peening spheres can be eliminated, and cost and maintainability can be improved. it can.

[0025]

Fourth Embodiment FIG. 8 is a schematic configuration diagram showing a fourth embodiment of the present invention. The differences between the fourth embodiment and the first embodiment are as follows. First, the gear rotating device can be rotated at a constant angle, and secondly, the peening sphere injection device 8c can also emit the peening sphere 7 for a fixed time in synchronization with the rotation of the gear 2. And thirdly, the interference object 4 is configured to be able to take a state in which a force is applied to the tooth tip of the gear 2 and a state in which no force is applied to the tooth tip. This is achieved not by the elastic deformation of the object 4 but by the interference object 4 itself moving mechanically so as not to hinder the movement of the tip of the gear 2. is there.

In the fourth embodiment, the gear 2 is rotated at a fixed angle from the state in which the tooth tip interferes with the interference object 4, and the interference object 4 is set in a state in which a force is applied to the tooth tip of the gear 2. In this state, a tensile stress is applied to the root area 6. The control unit 34 detects that this state has been reached, and the peening sphere injection device 8c operates the peening sphere 7 for a certain period of time.
Is applied to the root area and peened. When the peening for a certain period of time is completed, the interference object 4 is mechanically moved so that the movement of the tip of the gear 2 is not hindered, and the gear rotating device rotates by an angle corresponding to one tooth. Then, after confirming that the next tooth has moved to the peening position,
With the interference object 4 applying a force to the tip of the next tooth, a series of operations are repeated.

In addition, mechanically, a state in which a force is applied to the tooth tip of the gear 2 and a state in which no force is applied to the tooth tip are configured such that the plate-shaped interference object 4 can be moved up and down or left and right. Then, a configuration in which a position that interferes with the tooth tip and a position that is retracted from the tooth tip can be taken as an example can be exemplified. In addition, as shown in FIG. 6, the interfering object 4 is rotatably fixed by a pivot 33, and when a certain pressure or more, the interfering object 4 rotates around the pivot 33 (this state is indicated by an imaginary line). Show),
A configuration in which the movement of the tooth tip is free can be exemplified.
In this case, it is needless to say that the constant pressure corresponds to the tensile stress required in the root area 6.

According to this embodiment, since the peening sphere can be made to collide with the root area 6 where peening is required only for a predetermined time, the degree and accuracy of individual peening can be improved, and interference can be achieved. Since the object 4 does not hinder the movement of the teeth of the gear 2, breakage and deformation of the interfering object 4 can be suppressed. In addition, it is possible to prevent the tip of the gear 2 from being damaged by the interference object 4. The present invention is not limited to the above embodiments, and various design changes can be made without departing from the spirit of the present invention. Hereinafter, such an embodiment will be described.

(1) The specific configuration of the gear teeth and the interference object is as follows.
It is not limited to only the above embodiment. For example,
As another configuration of the interference object, a configuration such as a rack can be exemplified. In short, the configuration of the interfering object and the interfering object arranging device is not particularly limited as long as the peening sphere can be made to collide with the tooth root region from the peening sphere injection device and the tooth tip can be subjected to a tensile stress. . (2) In the above embodiment, the embodiment in which the interfering object and the peening sphere injection device are separately configured has been described. However, a configuration in which the peening sphere is injected from the interfering object may be adopted.
In this case, the interfering object disposition device also serves as the peening ball injection device. An example of such a configuration is a method in which a jet pipe 35 from which a peening sphere is projected is provided on the interference object 4 shown in FIG.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram for explaining a gear peening method and a gear peening apparatus of the present invention.

FIG. 2A is a perspective view showing a root area of a gear, and FIG.
(B) is a perspective view showing an example of an injection unit of the peening ball injection device.

FIG. 3A is a diagram showing a peening sphere distribution region of a conventional peening sphere injection device, and FIG. 3B is a diagram showing an example of a peening sphere distribution region of a peening sphere injection device according to the present embodiment. It is.

FIG. 4 is a longitudinal sectional view showing an example of a peening sphere injection device having a peening sphere distribution area control means.

FIG. 5A is a diagram showing a schematic configuration of a second embodiment according to the present invention, and FIGS. 5B and 5C are enlarged views for explaining the operation thereof;

FIG. 6 is a diagram showing a schematic configuration of a third embodiment according to the present invention.

FIG. 7A is a diagram showing a residual compressive stress after a primary peening step, and FIG. 7B is a diagram showing a residual compressive stress after a secondary peening step.

FIG. 8 is a diagram showing a schematic configuration of a fourth embodiment according to the present invention.

[Explanation of symbols]

Reference numeral 2 denotes a gear, 3 denotes a support shaft, 4 denotes an interfering object, 5 denotes an interfering object arranging device, 6, 6a, 6b denotes a tooth root area, 7 denotes a peening sphere, and 8 ...
Peening sphere injection device, 8a: first peening sphere injection device, 8b: second peening sphere injection device, 13: peening sphere emission unit, 14: peening sphere distribution area control means, 15
... Peening sphere distribution area.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Yosuke Morimoto 64 Ishizukitamachi, Sakai City, Osaka Prefecture Inside Kubota Sakai Plant (72) Inventor Yoshiaki Uenoyama 64 Ishizukitamachi, Sakai City, Osaka Prefecture Inside Kubota Sakai Plant

Claims (5)

[Claims] A gear (2) is mounted on a rotatable support shaft (3), and an interference object interferes with the tooth tip of the mounted gear (2).
(4) is disposed, the gear (2) is rotated by the rotation of the support shaft (3), and the tip of the gear (2) interferes with the interfering object (4).
A gear peening process characterized in that shot peening is performed by applying a peening body (7) to the root area (6) in a state where a tensile stress is generated in the root area (6) of (2). Method. 2. A gear rotating means having a support shaft (3) on which a gear (2) is mounted, and an interference object (4) interfering with the tooth tip of the gear 2;
Interfering object disposing means (5) for disposing the interfering object (4) such that the tooth tip of the mounted gear (2) and the interfering object (4) interfere with each other; Root area under stress
A gear peening apparatus comprising a peening body injection means (8) for causing a peening body (7) to collide with (6). 3. The gear peening processing apparatus according to claim 2, wherein the peening body injection means (8) causes the peening body (7) to collide with only the root region (6). ), A peening body distribution area control means (14) for controlling the distribution area (15) of (1). 4. A gear rotating means having a support shaft (3) on which a gear (2) can be mounted and which can rotate forward and backward, and a gear (2).
An interference object (4) that interferes with the tooth tip of the gear, and an interference object disposition means that arranges the interference object (4) so that the tooth tip of the mounted gear (2) and the interference object (4) interfere with each other. 5) and an interference object during forward rotation of the gear (4)
A first peening body injection section (8a, 1) that performs shot peening while aiming at the root area (6a) of the gear (2) while generating a tensile stress in the root area (6a) of the gear (2) due to interference with the gear.
3) and interference with the interfering object (4) during reverse rotation of the gear
And (2) a second peening body injection section (8b, 13) for performing shot peening while aiming at the root area (6b) in a state where a tensile stress is generated in the root area (6b). A gear peening processing device. 5. A gear (2) mounted on a rotatable support shaft (3), and an interference object so as to interfere with a tooth tip of the mounted gear (2).
(4) is disposed, the gear (2) is rotated by the rotation of the support shaft (3), and the tip of the gear (2) interferes with the interfering object (4).
A primary peening step of performing shot peening by applying a peening body (7) to the root area (6) in a state where a tensile stress is generated in the root area (6) of (2), and the primary peening step And then performing a shot peening by applying a peening body (7) having the same size as the peening body (7) in a state where no tensile stress is generated in the same root area (6). A gear peening method.