A method of shot peening for uniform strengthening

Abstract

The present application relates to a kind of even strengthened shot blasting method, by setting three spray guns, and adjusting three respectively aim at any tooth root of the gear to be shot blasted and the two sides adjacent to the tooth root;During the rotation of the gear, three spray guns can be respectively shot blasted to the tooth root and its two sides, at the same time, three spray guns can also be shot blasted to the tooth surface, compared with prior art, by setting three spray guns, the tooth root and its two sides are shot blasted respectively, the shot blasting effect is better, the residual stress value of the tooth root and its two sides is greatly increased, can reach the level after the tooth surface is shot blasted, so that the effect of the whole gear after shot blasting is even, it is beneficial to the improvement of gear fatigue strength.

Description

Technical Field

[0001] This invention relates to the field of metal surface treatment technology, and more specifically to a shot peening method for uniform strengthening. Background Technology

[0002] Shot peening of gear surfaces primarily utilizes the impact of high-speed shot on the surface of the part, causing elastic-plastic deformation. This results in beneficial changes such as residual compressive stress, work hardening, and microstructure refinement, thereby improving the gear's bending fatigue strength and contact fatigue strength. It is an important way to improve the gear's anti-galling ability and extend its service life. In existing technologies, when shot peening carburized gear parts, a shot gun is first aimed at the teeth of the stationary gear to be shot peened. Then, the gear is driven to rotate continuously in one direction, while the shot gun is driven to reciprocate along the gear's axial direction, allowing the jet stream to cover the thickness of the gear; ultimately, all teeth of the gear are shot-peened. Using existing shot peening methods, the shot peening effect at the gear tooth roots, especially on both sides of the tooth roots, is poor. The residual stress value is far below the level after shot peening at the tooth surface, resulting in uneven shot peening of the entire gear and hindering the improvement of gear fatigue strength. Summary of the Invention

[0003] The purpose of this invention is to address the problem in the prior art that after shot peening of gears, the shot peening effect on the gear tooth root and its sides is poor, and the residual stress value is much lower than that on the tooth surface, resulting in uneven shot peening effect on the entire gear. This invention provides a shot peening method for uniform strengthening.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A shot peening method for uniform strengthening, characterized by comprising the following steps:

[0006] a: Set up a first spray gun and two second and third spray guns on both sides, keep the gear to be shot peened stationary, and adjust the spray angle of the three spray guns so that: the first spray gun is aimed at any tooth root of the gear, the second and third spray guns are aimed at the two sides adjacent to the tooth root respectively, and in the direction of the gear's central axis, the projection of the jet stream of the second and third spray guns intersects with the projection of the jet stream of the first spray gun.

[0007] b: The drive gear rotates continuously, and at the same time, it drives the three spray guns to move synchronously back and forth along the axis of the gear, so that the spray flow of the three spray guns covers the thickness range of the gear.

[0008] The present invention, employing the aforementioned technical solution, utilizes three shot peening guns, each aimed at a tooth root and its adjacent two sides. During gear rotation, the three guns can simultaneously perform shot peening on the tooth root and its sides, as well as on the tooth surface. Compared to existing technologies where shot peening of gears results in poorer effects at the tooth root and its sides, with residual stress values ​​far lower than those on the tooth surface, leading to uneven overall shot peening, the present invention achieves better results by using three guns to target the tooth root and its sides. This significantly increases the residual stress values ​​at the tooth root and its sides, achieving levels comparable to those on the tooth surface, resulting in a more uniform overall shot peening effect and improving gear fatigue strength.

[0009] Furthermore, in step b, the gear is rotated alternately in a clockwise rotation and a counterclockwise rotation; this rotation method results in better shot peening uniformity compared to rotating the gear only clockwise or only counterclockwise.

[0010] Furthermore, in step a, the jet streams of the three spray guns are coplanar and perpendicular to the central axis of the gear, and the jet streams of the second and third spray guns intersect with the jet stream of the first spray gun. With this arrangement, the three spray guns are at the same height in the direction of the gear's central axis, which facilitates the installation of tooling. At the same time, since the jet streams are all perpendicular to the central axis of the gear, the spray guns are more accurately aligned with the gear teeth, resulting in a better shot peening strengthening effect.

[0011] Furthermore, in step a, the jet streams of the three spray guns are spatially staggered to avoid mutual interference between the jet streams and affect the shot peening effect.

[0012] Furthermore, in step a, adjusting the spray angle of the three spray guns includes the following steps:

[0013] a1: Keep the jet streams of the three spray guns coplanar and perpendicular to the central axis of the gear. Adjust the first spray gun to align with any tooth root of the gear, and align the second and third spray guns with the two sides adjacent to the tooth root respectively. The jet streams of the second and third spray guns intersect with the jet stream of the first spray gun respectively.

[0014] a2: Keep the projection of the jet streams from the three spray guns on the direction of the gear's central axis unchanged, and adjust the spray guns so that the jet streams of the three are spatially staggered.

[0015] Furthermore, in step a1, the first spray gun is directly facing the center of the tooth root, and the jet streams of the second and third spray guns are symmetrical about the jet stream axis of the first spray gun; with this configuration, the shot peening effect on both sides of the tooth root is more balanced.

[0016] Furthermore, in step a2, the second spray gun is adjusted to deflect towards one side of the gear, and the third spray gun is adjusted to deflect towards the other side of the gear by the same angle.

[0017] Furthermore, the deflection angles of the second and third spray guns do not exceed 5°; this avoids excessive deflection angles that would result in too small an angle between the jet stream and the teeth, thus affecting the shot peening effect.

[0018] Furthermore, after adjusting the second and third spray guns, the distance between the spray points of the second and third spray guns on the gear in the direction of the gear's central axis is no greater than 1 / 10 of the gear's thickness. This setting avoids the spray points of the three spray guns on the gear being too far apart, which helps to reduce the synchronous reciprocating movement stroke of the three spray guns and saves space.

[0019] The beneficial effects of this invention are as follows: By setting three spray guns to target the tooth root and its two sides respectively for shot peening, the shot peening effect is better, and the residual stress value of the tooth root and its two sides is greatly increased, which can reach the level of the tooth surface after shot peening. This makes the overall shot peening effect of the gear uniform and is conducive to improving the fatigue strength of the gear. The gear is rotated alternately clockwise and counterclockwise. Compared with rotating the gear only clockwise or only counterclockwise, this rotation method can make the shot peening uniformity better. The jet streams of the three spray guns are spatially staggered to avoid mutual interference between the jet streams and affect the shot peening effect. Attached image description:

[0020] Figure 1 This is a top view of the shot peening process of the present invention;

[0021] Figure 2 This is a schematic diagram of the shot peening process of the present invention.

[0022] Markings in the diagram: 1-First spray gun, 2-Second spray gun, 3-Third spray gun, 4-Gear, 5-Gear root, 6-Convergence point. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings.

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] This invention provides a shot peening method for uniform strengthening, comprising the following steps:

[0026] a: Set up a first spray gun 1 and two second spray guns 2 and three spray guns 3 on both sides. Keep the gear 4 to be shot peened stationary. Adjust the spray angle of the three spray guns so that: the first spray gun 1 is aligned with any tooth root 5 of the gear 4, the second spray gun 2 and the third spray gun 3 are aligned with the two sides adjacent to the tooth root 5 respectively, and in the direction of the central axis of the gear 4, the projection of the jet stream of the second spray gun 2 and the third spray gun 3 intersects with the projection of the jet stream of the first spray gun 1.

[0027] Specifically, such as Figure 1 As shown, the second spray gun 2 and its spray point on the gear are located on the opposite side of the spray flow of the first spray gun 1, and the third spray gun 3 and its spray point on the gear are located on the opposite side of the spray flow of the first spray gun 1; the two adjacent sides of the tooth root 5 are selected as: the two points where the arc tooth root 5 intersects with the planar tooth surface.

[0028] b: Drive gear 4 to rotate continuously, and at the same time, drive three spray guns to move synchronously back and forth in the axial direction of gear 4 so that the spray flow of the three spray guns covers the thickness range of gear 4.

[0029] Specifically, by adjusting the rotation cycle of the gears and the stroke and cycle of the reciprocating motion of the three spray guns, all tooth surfaces and tooth root areas of the gears can be shot-peened after rotating several times. It should be noted that the above-mentioned settings of the rotation cycle of the gears and the stroke and cycle of the reciprocating motion of the spray guns are existing technologies and are related to the specifications of the gear to be shot-peened (such as diameter, module, etc.). They are not innovative features of this patent and will not be elaborated here.

[0030] In step b, gear 4 is rotated alternately in a clockwise rotation and a counterclockwise rotation; alternatively, gear 4 may rotate continuously only in a clockwise or counterclockwise direction.

[0031] like Figure 2 As shown, in step a, the jet streams of the three spray guns are spatially staggered.

[0032] In step a, adjusting the spray angle of the three spray guns includes the following steps:

[0033] a1: Keep the jet streams of the three spray guns coplanar and perpendicular to the central axis of the gear 4. Adjust the first spray gun 1 to align with any tooth root 5 of the gear 4. The second spray gun 2 and the third spray gun 3 are respectively aligned with the two sides adjacent to the tooth root 5, and the jet streams of the second spray gun 2 and the third spray gun 3 intersect with the jet stream of the first spray gun 1.

[0034] a2: Keep the projection of the jet streams from the three spray guns on the central axis of the gear 4 unchanged, and adjust the spray guns so that the jet streams of the three are spatially staggered.

[0035] In step a1, the first spray gun 1 is directly opposite the center of the tooth root 5, and the jet streams of the second spray gun 2 and the third spray gun 3 are symmetrical about the jet stream axis of the first spray gun 1; as shown Figure 1 As shown, the jets from the first spray gun 1, the second spray gun 2, and the third spray gun 3 converge at a convergence point 6, which is located between the center of the tooth root 5 and the first spray gun 1.

[0036] In step a2, the second spray gun 2 is adjusted to deflect to one side of the gear 4, and the third spray gun 3 is adjusted to deflect to the other side of the gear 4 by the same angle.

[0037] The deflection angles of the second spray gun 2 and the third spray gun 3 do not exceed 5°.

[0038] After adjusting the second spray gun 2 and the third spray gun 3, the distance between the spray points of the second spray gun 2 and the third spray gun 3 on the gear 4 in the direction of the central axis of the gear 4 is no greater than 1 / 10 of the thickness of the gear 4.

[0039] In step a, the jet streams of the three spray guns can still be separated in space. At this time, there is some mutual interference between the jet streams, which will slightly reduce the shot peening strengthening effect of the tooth root and its two sides, but it is still significantly improved compared with the existing technology. At this time, the jet streams of the three spray guns are coplanar and all perpendicular to the central axis of the gear 4. The jet streams of the second spray gun 2 and the third spray gun 3 intersect with the jet stream of the first spray gun 1 respectively.

[0040] The present invention, employing the aforementioned technical solution, utilizes three spray guns, each aligned with a tooth root 5 and its adjacent two sides. During gear 4 rotation, the three spray guns can respectively perform shot peening on the tooth root 5 and its two sides, and simultaneously, also perform shot peening on the tooth surface. Compared to existing technologies where shot peening of gears results in poorer shot peening effects on the tooth root and its sides, with residual stress values ​​far lower than those on the tooth surface, leading to uneven shot peening of the entire gear, this invention addresses the problem by using three spray guns to respectively... Shot peening is performed on the tooth root and both sides, resulting in a better shot peening effect. It significantly increases the residual stress value of the tooth root and both sides, reaching the level of the tooth surface after shot peening. This makes the overall shot peening effect of the gear uniform and is beneficial to improving the fatigue strength of the gear. At the same time, rotating the gear alternately clockwise and counterclockwise one revolution results in better shot peening uniformity compared to rotating the gear only clockwise or only counterclockwise. The jet streams of the three spray guns are spatially staggered to avoid mutual interference between the jet streams and affect the shot peening effect.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for uniformly strengthening shot peening, characterized in that, Includes the following steps: a: Set up a first spray gun (1) and two second spray guns (2) and three spray guns (3) on both sides, keep the gear (4) to be shot peened stationary, and adjust the spray angle of the three spray guns so that: the first spray gun (1) is aligned with any tooth root (5) of the gear (4), the second spray gun (2) and the third spray gun (3) are aligned with the two sides adjacent to the tooth root (5) respectively, and in the direction of the central axis of the gear (4), the projection of the jet stream of the second spray gun (2) and the third spray gun (3) intersects with the projection of the jet stream of the first spray gun (1); the jet streams of the three spray guns are staggered in space; the two sides adjacent to the tooth root (5) are selected as: the two places where the arc tooth root (5) intersects with the plane tooth surface; b: Drive gear (4) to rotate continuously, and at the same time drive three spray guns to move synchronously back and forth in the axial direction of gear (4) so ​​that the spray flow of the three spray guns covers the thickness range of gear (4).

2. The uniformly strengthened shot peening method according to claim 1, characterized in that, In step b, the gear (4) is rotated alternately in a clockwise rotation and a counterclockwise rotation.

3. The uniformly strengthened shot peening method according to claim 1, characterized in that, In step a, the jet streams of the three spray guns are coplanar and perpendicular to the central axis of the gear (4), and the jet streams of the second spray gun (2) and the third spray gun (3) intersect with the jet stream of the first spray gun (1).

4. The uniformly strengthened shot peening method according to claim 1, characterized in that, In step a, adjusting the spray angle of the three spray guns includes the following steps: a1: Keep the jet streams of the three spray guns coplanar and perpendicular to the central axis of the gear (4), adjust the first spray gun (1) to align with any tooth root (5) of the gear (4), the second spray gun (2) and the third spray gun (3) to align with the two sides adjacent to the tooth root (5) respectively, and the jet streams of the second spray gun (2) and the third spray gun (3) intersect with the jet stream of the first spray gun (1) respectively; a2: Keep the projection of the jet streams of the three spray guns on the central axis of the gear (4) unchanged, and adjust the spray guns so that the jet streams of the three are spatially staggered.

5. The uniformly strengthened shot peening method according to claim 4, characterized in that, In step a1, the first spray gun (1) is directly opposite the center of the tooth root (5), and the jet streams of the second spray gun (2) and the third spray gun (3) are symmetrical about the jet stream axis of the first spray gun (1).

6. The uniformly strengthened shot peening method according to claim 5, characterized in that, In step a2, the second spray gun (2) is adjusted to deflect to one side of the gear (4), and the third spray gun (3) is adjusted to deflect to the other side of the gear (4) by the same angle.

7. The uniformly strengthened shot peening method according to claim 6, characterized in that, The deflection angles of the second spray gun (2) and the third spray gun (3) do not exceed 5°.

8. The uniformly strengthened shot peening method according to claim 6, characterized in that, After adjusting the second spray gun (2) and the third spray gun (3), the distance between the spray points of the second spray gun (2) and the third spray gun (3) on the gear (4) in the direction of the central axis of the gear (4) is not greater than 1 / 10 of the thickness of the gear (4).

Images