JP2006258239A - Belleville spring and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a belleville spring and its manufacturing method provided with a rotation prevention tooth capable of having high durability on an outer periphery. <P>SOLUTION: A shot-peening worked surface 12 is formed on a base part of the tooth 11 by performing shot-peening working. Residual stress is given onto the shot peening worked surface 12 and when the belleville spring 1 is arranged between a driven plate of a clutch mechanism and a piston, high fatigue strength can be exhibited. Further, since a sharp edge of the base part of the tooth 11 is removed, concentration of stress generated on the base part of the tooth 11 can be relaxed. Further, since sharp edges of an outer peripheral edge of a body 10 supported on the driven plate and the tooth 11 and an inner peripheral edge of the body supported on the piston are not removed, each of a support position of the driven plate at the outer peripheral edge of the body 10 and a support position of the piston at the inner peripheral edge of the body 10 is not deviated from a predetermined design position in a radial direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a disc spring used for absorbing a shock generated when a clutch of a multi-plate clutch mechanism of a transport machine is engaged, and a manufacturing method thereof, and more particularly, a disc spring having teeth for preventing relative rotation with respect to a clutch drum. Relates to improved technology.

  A wet multi-plate clutch mechanism is used as a clutch mechanism in a transmission of a transport machine. The wet multi-plate clutch mechanism uses a disc spring that absorbs shock generated when the clutch is engaged. FIG. 4 is an enlarged side sectional view showing a configuration of a multi-plate clutch mechanism 100 to which a conventional disc spring 200 is applied. The multi-plate clutch mechanism 100 includes a clutch drum 101 having a substantially bottomed cylindrical shape, and a plurality of spline grooves 101A extending in the axial direction are formed in the circumferential direction on the inner peripheral surface thereof. Inside the clutch drum 101, a cylindrical clutch hub 102 whose rotational axis line coincides with it is provided, and a plurality of spline grooves 102A extending in the axial direction are formed in the circumferential direction on the outer peripheral surface thereof.

  Between the clutch drum 101 and the clutch hub 102, a driven plate 103 fitted in the spline groove 101A of the clutch drum 101 and a drive plate 104 fitted in the spline groove 102A of the clutch hub 102 move in the axial direction. They are arranged alternately at a predetermined interval. A piston 105 is provided on the bottom surface side of the clutch drum 101 so as to be movable in the axial direction, and a hydraulic chamber 106 is formed between the piston 105 and the clutch drum 101.

  Between the driven plate 103 on the bottom surface side of the clutch drum 101 and the piston 105, a disc spring 200 having a circular disc shape with a hole formed in the center is provided. The disc spring 200 is disposed such that the outer peripheral surface thereof is supported by the driven plate 103 and the inner peripheral surface thereof is supported by the piston 105.

  In the multi-plate clutch mechanism 100 as described above, when hydraulic oil is supplied to the hydraulic chamber 106, the piston 105 driven by the hydraulic pressure presses the driven plate 103 on the bottom surface side of the clutch drum 101 via the disc spring 200. Then, the driven plate 103 on the bottom side moves to the opening side of the clutch drum 101, the friction surfaces of the driven plate 103 and the drive plate 104 facing each other engage, and the clutch is engaged. At this time, the disc spring 200 absorbs a shock generated at the time of clutch engagement by elastically deforming so as to be substantially flat from the disc shape.

  Incidentally, since the disc spring 200 has a circular shape, the disc spring 200 easily rotates relative to the clutch drum 101 when the clutch mechanism 100 rotates. For this reason, there is a problem that the disc spring 200 frequently collides with the inner wall of the clutch drum 101, and as a result, the inner wall of the clutch drum 101 is damaged.

  Therefore, in order to solve the above problem, as shown in FIG. 5, a disc spring in which a plurality of teeth 311 are formed on the outer periphery of a main body 310 having a circular dish shape with a hole 310A formed in the center. 300 is proposed (for example, Patent Document 1). In the disc spring 300, the main body 310 is installed inside the clutch drum 101 so that its teeth 311 are fitted with the spline groove 101A on the inner peripheral surface of the clutch drum 101. Rotation can be prevented.

JP 2001-295860 A

  However, the disc spring 300 has a problem that the durability of the disc spring 300 is greatly reduced because stress concentration occurs at the root portion of the tooth 311 during elastic deformation at the time of clutch engagement.

  Therefore, in order to reduce the generated stress at the root portion of the tooth 311, it is conceivable to increase the radius of curvature of the arc portion 311 </ b> A at the root portion of the tooth 311.

  However, in this case, since the arc portion 311A at the base portion of the tooth 311 projects outward in the radial direction so as to expand in the circumferential direction, when the shape of the spline groove 101A of the clutch drum 101 is sharp, its sharp edge And the arc portion 311A are likely to collide with each other. For this reason, wear of the spline groove 101A by the teeth 311 increases. Further, since the length of the straight portion 311B on the side surface portion of the tooth 311 is reduced, the fitting area of the tooth 311 with the spline groove 101A is reduced. As a result, the contact surface pressure between the tooth 311 and the spline groove 101A increases, and wear of the spline groove 101A by the tooth 311 increases.

  On the other hand, in order to improve the durability of the disc spring 300, it is conceivable to increase the fatigue strength by applying a residual stress to the disc spring 300 by performing multi-stage shot peening processing on the entire disc spring 300. (For example, Patent Document 2).

  However, in this case, since multistage shot peening is performed on the whole disc spring 300, the outer peripheral edge of the main body 310 and the teeth 311 supported by the driven plate 103 and the inner peripheral edge of the main body 310 supported by the piston 105. The sharp edge removal amount increases, and the end surface curvatures of the outer peripheral edge and the inner peripheral edge increase. For this reason, since the fitting area of the tooth 311 with the spline groove 101A becomes small, the contact surface pressure between the tooth 311 and the spline groove 101A increases. As a result, the wear of the spline groove 101A due to the teeth 311 is increased, and the durability of the multi-plate clutch mechanism 100 is greatly reduced. Further, since the support position of the driven plate 103 at the outer peripheral edge portion of the main body 310 and the support position of the piston 105 at the inner peripheral edge portion of the main body 310 are shifted from the predetermined design position in the radial direction, the load characteristics change and the desired characteristics are changed. There is a problem that cannot be obtained. In particular, since the disc spring 300 is required to have high durability in order to cope with the increase in the guaranteed traveling distance of automobiles in recent years, the above problems are serious.

JP 2000-27915 A

  Therefore, an object of the present invention is to provide a disc spring and a method for manufacturing the same that can reduce the load stress on the root of the tooth as well as the wear of the spline groove due to the tooth. It is said.

  The disc spring of the present invention is a disc spring having teeth projecting radially outward on the outer peripheral portion of a circular dish-shaped main body, and is characterized in that shot peening is performed on the root portion of the tooth. Yes.

  In the disc spring of the present invention, since shot peening is performed on the root of the tooth, only the sharp edge of the root of the tooth can be removed, and the root of the tooth that is in a high stress state can be efficiently removed. Since a high residual stress can be applied, the durability of the disc spring can be improved.

  The disc spring of the present invention can be arranged in various mechanisms. For example, the disc spring of this invention can be arrange | positioned between the 2nd member provided so that the movement to the axial direction was possible inside the cylindrical 1st member, and the 3rd member. In this case, the teeth can be fitted into a groove formed on the inner peripheral surface of the first member.

  In the above aspect, when the disc spring of the present invention is disposed between the driven plate of the clutch mechanism of the transport machine and the piston, the high residual stress is efficiently applied to the root portion of the tooth that is in a high stress state as described above. Therefore, high fatigue strength can be exhibited. Further, since only the sharp edge at the root of the tooth is removed, stress concentration generated at the root of the tooth can be reduced. Furthermore, since the sharp edges of the outer peripheral edge of the main body and teeth supported by the driven plate and the inner peripheral edge of the main body supported by the piston are not removed, the multi-plate clutch mechanism supports the driven plate at the outer peripheral edge of the main body. The position and the support position of the piston at the inner peripheral edge of the main body do not deviate from the predetermined design position in the radial direction. As a result, load characteristics can be improved.

  Furthermore, since it is not necessary to increase the radius of curvature of the root of the tooth, even when the shape of the spline groove of the clutch drum is sharp, it is possible to prevent the sharp edge from colliding with the root of the tooth. In addition, since the linear portion of the side surface portion of the tooth is long, the fitting area with the tooth spline groove is increased, and the contact surface pressure between the tooth and the spline groove can be reduced. Thereby, abrasion of the spline groove due to teeth can be reduced. In addition, since the shot peening process is performed only on the root portion of the tooth, the flatness of the main body can be improved. Thereby, a multi-plate clutch mechanism having desired characteristics can be obtained.

  As described above, by applying shot peening to the root of the tooth, without increasing the end surface curvature of the inner and outer peripheral edge of the main body and the outer peripheral edge of the tooth, the root of the tooth that becomes a high stress state Thus, the high residual stress can be efficiently applied, so that the durability of the disc spring can be improved. In particular, when multi-stage shot peening is performed as described below, the effect becomes remarkable. Therefore, since the durability of the multi-plate clutch mechanism in which the disc spring of the present invention is arranged can be improved, it is possible to cope with an increase in the guaranteed traveling distance of the automobile.

  The disc spring manufacturing method of the present invention is characterized in that teeth are formed on the outer periphery of a circular dish-shaped main body so as to protrude radially outward, and shot peening is performed on the root of the teeth. Yes.

  In the disc spring manufacturing method of the present invention, since shot peening is performed only on the root of the tooth, the processing time required to obtain the desired residual stress can be shortened. Moreover, the disc spring obtained by the manufacturing method of the disc spring of this invention can obtain the effect | action and effect similar to the said disc spring.

  Here, a various form can be used for the manufacturing method of said disc spring. For example, the shot peening can be performed on the entire body and teeth before the shot peening performed on the root of the tooth. In such an aspect, in addition to the root portion of the tooth, residual stress can be applied to the entire disc spring. In this case, since only one stage of shot peening is performed on the entire body and teeth, the outer peripheral edge of the body and the inner peripheral edge of the body are sharper than when multiple stages of shot peening are performed. Edge removal can be suppressed.

  The shot peening process performed on the root of the tooth can be a multi-stage shot peening process. In this case, the diameter of the shot used in the later stage shot peening process can be made smaller than the diameter of the shot used in the previous stage shot peening process. In such an embodiment, notch sensitivity can be reduced by improving the surface roughness of the root of the tooth, and the residual stress in the vicinity of the surface at the root of the tooth can be further increased.

  The disc spring of the present invention is a disc spring disposed between the second member and the third member provided to be movable in the axial direction inside the cylindrical first member, and has a circular disc shape. The teeth that fit into the grooves formed on the inner peripheral surface of the first member are formed on the outer peripheral portion of the main body so as to protrude radially outward, and the shot peening process is performed on the root portion of the teeth by shot peening. It is characterized by forming a surface.

  According to the disc spring of the present invention or the manufacturing method thereof, by applying shot peening to the root portion of the tooth, it is possible to achieve a high stress state without increasing the end surface curvature of the inner and outer peripheral edge portions of the main body portion and the outer peripheral edge portion of the tooth. Since the high residual stress can be efficiently applied to the root portion of the tooth, the effect of improving the durability of the disc spring can be obtained.

(1) Configuration of Embodiment (1-1) Disc Spring Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1A and 1B are views showing a configuration of a disc spring 1 according to an embodiment of the present invention, in which FIG. 1A is a plan view, FIG. 1B is a side sectional view taken along line I-II in FIG. FIG. 2 is a partially enlarged view of (A).

  The disc spring 1 includes a main body 10 having a circular dish shape, and a circular hole 10 </ b> A is formed at the center of the main body 10. A plurality of (for example, six) teeth 11 that are substantially rectangular and project outward in the radial direction are formed on the outer peripheral portion of the main body 10 at equal intervals in the circumferential direction. For example, when the teeth 11 are applied to the clutch mechanism 100 described below, the teeth 11 have a function of preventing the disc spring 1 from rotating relative to the clutch drum 101. The teeth to which the present invention is applied are not limited to the teeth 11 shown in FIG. 1, and it goes without saying that the present invention can be applied to teeth having various shapes. For example, the present invention can be applied to teeth having a shape extending along the outer peripheral surface of the main body 10 without being bent with respect to the outer peripheral surface of the main body 10. Moreover, although the number of the teeth 11 was set to 6, it is not limited to this, The number can be set arbitrarily. Furthermore, the interval between the plurality of teeth may not be equal to each other and can be arbitrarily set.

  A shot peening surface 12 is formed at the root of the tooth 11. Residual stress is applied to the shot peened surface 12 by shot peening, and the sharp edges are removed. The shot peening process is performed using, for example, a shot peening apparatus 20 shown in FIG. 2 after the circular dish-shaped disc spring 1 having the holes 10A and the teeth 11 is formed by pressing. FIG. 2 is a schematic perspective view showing how the shot peening surface 12 is formed at the root of the tooth 11 of FIG. 1 using the shot peening apparatus 20.

  The shot peening apparatus 20 is an air nozzle type shot peening apparatus. The shot peening apparatus 20 includes a nozzle 21 that locally projects a shot 22 at a predetermined timing toward a disc spring 1 that is a workpiece. The shot 22 is supplied from the shot supply unit and is projected at a high speed by the high-pressure air flow from the high-pressure air supply unit. The disc spring 1 is attached to a rotating disk that rotates at a predetermined speed or a rotating disk that is fed at a predetermined feed angle.

  In the shot peening apparatus 20, the teeth 11 of the disc spring 1 are locally projected at high speed from the nozzle 21 toward the root portion of the teeth 11 of the disc spring 1 rotating at a predetermined speed. The shot peened surface 12 is formed at the root of the surface.

(1-2) Clutch Mechanism The disc spring 1 described above can be applied to a clutch mechanism 100 as shown in FIG. 3A and 3B show the configuration of the clutch mechanism 100, where FIG. 3A is an enlarged side sectional view and FIG. 3B is an exploded view. In FIG. 3B, illustration of the clutch hub 102 is omitted.

  The clutch mechanism 100 is a wet multi-plate clutch used in, for example, an AT car of an automobile. The clutch mechanism 100 includes a clutch drum 101 (first member) having a substantially bottomed cylindrical shape, and a plurality of spline grooves 101A (grooves) extending in the axial direction are equally spaced in the circumferential direction on the inner peripheral surface thereof. Is formed. A cylindrical clutch hub 102 whose rotational axis line coincides with the clutch drum 101 is provided inside the clutch drum 101, and a plurality of spline grooves 102 </ b> A extending in the axial direction are arranged at equal intervals in the circumferential direction on the outer peripheral surface thereof. Is formed.

  Between the clutch drum 101 and the clutch hub 102, a disk-shaped driven plate 103 (second member) having a circular hole formed at the center thereof and a drive plate 104 are alternately arranged at a predetermined interval. Is arranged. In the driven plate 103, a plurality of teeth are formed on the outer peripheral edge at equal intervals in the circumferential direction, and these teeth are fitted in the spline groove 101A. As a result, the driven plate 103 cannot rotate relative to the clutch drum 101 but can move in the axial direction. In the drive plate 104, a plurality of teeth are formed on the inner peripheral edge at equal intervals in the circumferential direction, and these teeth are fitted in the spline groove 102A. Thus, the drive plate 104 cannot move relative to the clutch hub 102 but can move in the axial direction.

  A piston 105 (third member) is disposed on the bottom surface side of the clutch drum 101 so as to be movable in the axial direction. A hydraulic chamber 106 to which hydraulic oil is supplied is formed between the clutch drum 101 and the piston 105. The piston 105 is driven in the axial direction by hydraulic oil supplied to the hydraulic chamber 106. One end of a return spring 107 that is expanded and contracted by pressure applied thereto is fixed to the opening side surface of the piston 105. The other end of the return spring 107 is fixed to a spring retainer 108 provided on the clutch drum 101. The return spring 107 biases the piston 105 toward the bottom surface side of the clutch drum 101.

  The disc spring 1 is disposed between the driven plate 103 on the bottom side of the clutch drum 101 and the piston 105. In this case, the disc spring 1 has the teeth 11 fitted in the spline groove 101A, the surface of the outer peripheral edge of the main body 10 is supported by the driven plate 103, and the back surface of the inner peripheral edge of the main body 10 is supported by the piston 105. It is arranged to be supported. Thus, the disc spring 1 cannot move relative to the clutch drum 101 but can move in the axial direction.

  On the opening side of the clutch drum 101, a plate 109 for restricting the driven plate 103 and the drive plate 104 from moving by a predetermined amount or more in the axial direction is disposed. In the plate 109, a plurality of teeth are formed on the outer peripheral edge at equal intervals in the circumferential direction, and these teeth are fitted in the spline groove 101A. Thereby, the plate 109 cannot move relative to the clutch drum 101 but can move in the axial direction. A snap ring 110 is disposed on the opening side surface of the plate 109 to prevent the plate 109 from being detached to the outside. The snap ring 110 is locked in a ring groove formed at the opening side end of the clutch drum 101.

(2) Operation of Embodiment Next, the operation of the clutch mechanism 100 to which the disc spring 1 is applied will be described mainly with reference to FIG.

  When hydraulic oil is supplied to the hydraulic chamber 106, the piston 105 driven by the hydraulic pressure moves to the opening side in the axial direction against the urging force of the return spring 107, and the bottom side of the clutch drum 101 via the disc spring 1. The driven plate 103 is pressed. Then, the driven plate 103, the drive plate 104, and the plate 109 that are alternately arranged move to the opening side in the axial direction. When the plate 109 is pressed against the snap ring 110 by such movement, the friction surfaces of the driven plate 103 and the drive plate 104 facing each other are engaged and the clutch is engaged. Thereby, torque transmission between the clutch drum 101 and the clutch hub 102 becomes possible.

  At this time, the disc spring 1 absorbs a shock generated when the clutch is engaged by elastically deforming so as to be substantially flat from the disc shape. In this case, the stress concentration generated at the root portion of the tooth 11 during elastic deformation of the disc spring 1 is alleviated by the shot peening surface 12. Further, collision between the root portion of the tooth 11 and the spline groove 101A is prevented.

  Next, when the supply of hydraulic oil to the hydraulic chamber 106 is stopped, the piston 105 is pushed back to the bottom surface side of the clutch drum 101 by the urging force of the return spring 107. Then, the engagement of the friction surfaces of the driven plate 103 and the drive plate 104 is released, the clutch engagement is released, and the shape of the disc spring 1 returns to the original state.

  In the above embodiment, since shot peening is performed on the root portion of the tooth 11, only the sharp edge of the root portion of the tooth 11 can be removed and the root portion of the tooth 11 that is in a high stress state can be removed. Since the high residual stress can be efficiently applied, the durability of the disc spring 1 can be improved.

  In particular, when the disc spring 1 is disposed between the driven plate 103 and the piston 105 of the clutch mechanism 100 of the transport machine, the high residual stress is efficiently applied to the root portion of the tooth 11 that is in a high stress state as described above. Therefore, high fatigue strength can be exhibited. In addition, since only the sharp edge at the root portion of the tooth 11 is removed, stress concentration generated at the root portion of the tooth 11 can be reduced. In addition, since the sharp edges of the outer peripheral edge of the main body 10 and the teeth 11 supported by the driven plate 103 and the inner peripheral edge of the main body 10 supported by the piston 105 are not removed, the clutch mechanism 100 has the outer peripheral edge of the main body 10. The support position of the driven plate 103 and the support position of the piston 105 at the inner peripheral edge of the main body 10 do not deviate from the predetermined design position in the radial direction. As a result, load characteristics can be improved.

  Further, since it is not necessary to increase the radius of curvature of the root portion of the tooth 11, even when the shape of the spline groove 101 </ b> A of the clutch drum 101 is sharp, it is possible to prevent the sharp edge from colliding with the root portion of the tooth 11. it can. In addition, since the straight portion of the side surface portion of the tooth 11 is long, the fitting area of the tooth 11 with the spline groove 101A is increased, and the contact surface pressure between the tooth 11 and the spline groove 101A can be reduced. Thereby, wear of the spline groove 101A by the teeth 11 can be reduced. In addition, since the shot peening process is performed only on the root portion of the tooth 11, the flatness of the main body 10 can be improved. Thereby, the clutch mechanism 100 having desired characteristics can be obtained.

  As described above, by performing shot peening on the root portion of the tooth 11, the end surface curvature of the inner and outer peripheral edge portions of the main body portion 10 and the outer peripheral edge portion of the tooth 11 can be increased without increasing the end surface curvature of the tooth 11. Since a high residual stress can be efficiently applied to the root portion, the durability of the disc spring 1 can be improved. Therefore, the durability of the multi-plate clutch mechanism 100 in which the disc spring 1 of the present embodiment is disposed can be improved, and therefore it is possible to cope with an increase in the guaranteed traveling distance of the automobile. Furthermore, since the shot peening process is performed only on the root portion of the tooth 11, the processing time required to obtain a desired residual stress can be shortened.

(3) Modifications While the present invention has been described with reference to the above embodiment, the present invention is not limited to the above embodiment, and various modifications are possible. For example, the shot peening process can be performed on the entire body 10 and the teeth 11 before the shot peening process performed on the root portion of the teeth 11. In the shot peening process performed on the entire body 10 and teeth 11, the processing can be performed by a continuous or tumbler type processing apparatus using the air nozzle type shot peening apparatus 20 or the impeller type shot peening apparatus. When an air nozzle type shot peening apparatus is used, shot peening is performed on one side or both sides of the disc spring 1. When a tumbler type processing apparatus is used, shot peening is performed collectively by putting a large number of disc springs 1 inside the apparatus.

  In the above aspect, in addition to the root portion of the tooth 11, residual stress can be applied to the entire disc spring 1. In this case, since only one stage of shot peening is performed on the entire body 10 and teeth 11, the outer peripheral edge and the inner peripheral edge of the body 10 are compared with the case of performing multiple stages of shot peening. Removal of sharp edges can be suppressed.

  For example, the shot peening process performed on the root portion of the tooth 11 can be a multi-stage shot peening process. In this case, the diameter of the shot used in the shot peening process at the later stage can be made smaller than the diameter of the shot used in the shot peening process at the previous stage. In such an aspect, the notch sensitivity can be reduced by improving the surface roughness of the root portion of the tooth 11, and the residual stress in the vicinity of the surface at the root portion of the tooth 11 can be further increased.

  Furthermore, in the said embodiment, although the disc spring 1 of this invention was applied to the wet multi-plate type clutch used for AT car of a motor vehicle, it is not limited to this. For example, the disc spring 1 of the present invention can be applied to a multi-plate clutch mechanism of a transport machine such as a construction machine or a motorcycle.

  Hereinafter, an embodiment of the present invention will be described in more detail with reference to specific examples.

(A) Flatness of the disc spring [Example 1, Comparative Example 1]
As Example 1 of the present invention, each of plate springs having plate thicknesses of 1.0 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2.0 mm, and 2.5 mm using an air nozzle type shot peening apparatus, respectively. On the other hand, shot peening was performed on the root of the teeth. The shot peening process of Example 1 was performed on the root part of a total of 8 teeth using steel beads having a nominal diameter of 40 μm and a projection pressure of 0.4 MPa with respect to the root part of one tooth for 5 seconds. The result of examining the flatness of the disc spring of Example 1 is shown in FIG. The data of Example 1 is plotted with ■. As Comparative Example 1, using an air nozzle type shot peening apparatus, each plate spring having a plate thickness of 1.0 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2.0 mm, and 2.5 mm was used. Then, shot peening was performed on the entire body and both sides of the teeth. In the shot peening process of Comparative Example 1, a cut wire having a nominal diameter of 0.45 mm was used and projection was performed for 30 minutes. The result of examining the flatness of the disc spring of Comparative Example 1 is shown in FIG. The data of Comparative Example 1 is plotted with ●.

  As can be seen from FIG. 6, in Example 1, compared to Comparative Example 1, shot peening was performed only on the root portion of the teeth, so it was confirmed that good flatness was obtained. Therefore, in the first embodiment, since the disc spring can obtain desired characteristics, the disc spring and the characteristics of the clutch mechanism to which the disc spring is applied can be stabilized, and thereby a longer life can be achieved. I understood.

(B) About the end surface curvature of the side part and root part of the tooth | gear of a disc spring [Example 2, comparative example 2]
As Example 2 of the present invention, using an air nozzle type shot peening apparatus, shot peening processing is performed for 0 sec, 3 sec, 5 sec, 10 sec, 20 sec on part B which is one sharp edge of the root of the tooth shown in FIG. For each of the disc springs for 30 seconds, the A portion which is the sharp edge of the tooth side surface shown in FIG. 7, the B portion which is the sharp edge of the tooth root portion, and the A portion of the side surface portion of the tooth opposite to the A portion. The end face curvature of the C part which is a sharp edge was examined. The result is shown in FIG. The data of part A of Example 2 is plotted with ♦, the data of part B of Example 2 is plotted with ■, and the data of part C of Example 2 is plotted with ▲. In the shot peening process of Example 2, steel beads having a nominal diameter of 40 μm were used, and the projection pressure was set to 0.4 MPa on the root portion of one tooth for 5 seconds for a total of 8 teeth.

  As Comparative Example 2, each of the disc springs in which shot peening was performed for 0 min, 5 min, 10 min, 15 min, 25 min, and 30 min on the tooth body and one side of the tooth using an air nozzle type shot peening apparatus was performed in Example 2. As shown in FIG. 7, the A portion that is the sharp edge of the tooth side surface portion shown in FIG. 7, the B portion that is the sharp edge of the tooth root portion, and the C portion that is the sharp edge opposite to the A portion of the tooth side surface portion. The end face curvature of was examined. The result is shown in FIG. The data of part A of Comparative Example 2 is plotted with ◆, and the data of Part B of Comparative Example 2 is plotted with ▪. In the shot peening process of Comparative Example 2, a cut wire having a nominal diameter of 0.45 mm was used and projection was performed for 20 minutes. In Example 2 and Comparative Example 2, the surface subjected to shot peening is a surface where tensile stress is generated when applied to a multi-plate clutch mechanism.

  As can be seen from FIG. 8 and FIG. 9, in Example 2, it was confirmed that the B portion of the root portion of the tooth had a large end face curvature in a short processing time as compared with Comparative Example 2. Moreover, in Example 2, compared with Comparative Example 2, since shot peening was performed only on the B portion of the root of the tooth, the end surface of the A portion of the side surface of the tooth adjacent to the B portion of the root of the tooth It was confirmed that the curvature was small. Further, in Comparative Example 2, when shot peening is performed on the entire surface of one side of the tooth and the main body so that only the A portion of the side surface portion of the tooth has an end surface curvature, the opposite end portion curvature of the C portion on the opposite side is also given. It was confirmed that the On the other hand, in Example 2, since shot peening was performed only on the B part on one side of the root part of the tooth, the end face curvature of the C part on the opposite side was kept at 0.02 to 0.06. I was able to confirm. Thus, it was confirmed that the influence of the shot peening process was not exerted on the C part of the side surface part of the tooth that was not subjected to the shot peening process. Therefore, in Example 2, it turned out that the manufacturing efficiency of a disc spring can be improved by performing shot peening process only to the surface by the side of the tensile stress generation of the root part of a tooth. Moreover, in Example 2, since the shape of the tooth | gear side part can be hold | maintained, it turned out that the clutch mechanism to which a disc spring is applied can ensure long life.

(C) About surface residual stress imparting efficiency of arc portion of tooth root [Example 3, Comparative Example 3]
As Example 3 of the present invention, using an air nozzle type shot peening device, each of the disc springs subjected to shot peening at the root of the tooth for 0 sec, 1 sec, 3 sec, 5 sec, 7 sec, 10 sec, 15 sec, 20 sec, 30 sec The surface residual stress of the arc at the root of the tooth was examined. The result is shown in FIG. In the shot peening process of Example 3, steel beads having a nominal diameter of 40 μm were used, and the projection pressure was set to 0.4 MPa with respect to the root portion of one tooth for 5 seconds for a total of 8 tooth root portions. . As Comparative Example 3, using an air nozzle type shot peening apparatus, the arc root portion of the tooth root for each of the disc springs subjected to shot peening at the tooth root for 0 min, 5 min, 10 min, 15 min, 25 min, 30 min The surface residual stress of was investigated. The result is shown in FIG. In the shot peening process of Comparative Example 3, a cut wire having a nominal diameter of 0.45 mm was used and projection was performed for 20 minutes.

  As can be seen from FIGS. 10 and 11, in order to obtain a desired residual stress, in Comparative Example 3, a long processing time of 20 minutes or more per sheet is required in one batch process. It was confirmed that the processing time was shortened to about 5 seconds.

(D) Surface residual stress distribution at root of tooth [Example 4, Comparative Example 4]
As Example 4 of the present invention, an air nozzle type shot peening apparatus is used to perform the first-stage shot peening process on the entire body of the disc spring and one side of the tooth, and then 2 only on one side of the root of the tooth. Step shot peening was performed to investigate the residual stress distribution at the root of the tooth. The result is shown in FIG. The data of Example 4 is plotted with ■. In the shot peening process of Example 4, using a cut wire having a nominal diameter of 0.45 mm in the entire first stage shot peening process, projection is performed for 20 minutes, and in the second stage local shot peening process, Using steel beads with a nominal diameter of 40 μm, a projection pressure of 0.4 MPa was applied to the root of one tooth for 5 seconds, and a total of 8 tooth roots were applied. As Comparative Example 4, shot peening was performed on the whole body of the disc spring and one side of the tooth using an air nozzle type shot peening apparatus, and the residual stress distribution at the root of the tooth was examined. The result is shown in FIG. The data of Comparative Example 4 is plotted with ●. In the shot peening process of Comparative Example 4, a cut wire having a nominal diameter of 0.45 mm was used and projection was performed for 20 minutes.

  As can be seen from FIG. 12, in Example 4, since the second-stage shot peening process was performed only on one side of the root of the tooth, compared with Comparative Example 4, the highest load stress was obtained at the root of the tooth. It was confirmed that a high residual stress was applied to the surface portion. Therefore, in Example 4, it turned out that durability of a disk spring can be improved compared with the comparative example 4. FIG.

It is a figure showing the structure of the disc spring which concerns on one Embodiment of this invention, (A) is a top view, (B) is a sectional side view of the II-II line of (A), (C) is (B). It is a partial enlarged view. It is a schematic perspective view showing a mode that the shot peening process surface is formed in the root part of the tooth | gear of FIG. It is a figure showing the structure of the clutch mechanism to which the disc spring of FIG. 1 is applied, (A) is an expanded sectional side view, (B) is an exploded view. It is side sectional drawing showing the structure of the multi-plate clutch mechanism to which the conventional disc spring is applied. It is a figure showing the structure of the other conventional disk spring, (A) is a top view, (B) is a sectional side view of the II-II line of (A), (C) is the elements on larger scale of (A). is there. It is a graph showing the plate | board thickness dependence of the flatness of the disc spring of Example 1 and Comparative Example 1 of this invention. It is a graph showing the shot-peening process time dependence of the end surface curvature of the side edge part of the tooth | gear of Example 2 of this invention, and the sharp edge of a root part. It is a graph showing the shot peening processing time dependence of the end surface curvature of the side edge part of the tooth | gear of comparative example 2, and a root part. It is a perspective view showing the schematic structure of the tooth | gear of the disk spring for demonstrating FIG. 7 and FIG. It is a graph showing the shot peening processing time dependence of the surface residual stress of the circular arc part in the root part of the tooth | gear of Example 3 of this invention. It is a graph showing the shot-peening process time dependence of the surface residual stress of the circular arc part in the root part of the tooth | gear of the comparative example 3. It is a graph showing the residual stress distribution of the root part of the tooth | gear of Example 4 and Comparative Example 4 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Belleville spring, 10 ... Main body, 11 ... Teeth, 12 ... Shot peening surface, 101 ... Clutch drum (first member), 101A ... Spline groove (groove), 103 ... Driven plate (second member), 105 ... Piston (third member)

Claims (5)

In a disc spring having teeth projecting outward in the radial direction on the outer peripheral portion of a circular dish-shaped main body,
A disc spring characterized by performing shot peening on the root of the tooth.   The disc spring is disposed between a second member and a third member which are provided so as to be movable in the axial direction inside the cylindrical first member, and the teeth are arranged on an inner peripheral surface of the first member. The disc spring according to claim 1, wherein the disc spring is fitted into the formed groove. On the outer periphery of the circular dish-shaped body, teeth are formed so as to protrude outward in the radial direction,
A method of manufacturing a disc spring, comprising performing shot peening on the root of the tooth.   4. The method of manufacturing a disc spring according to claim 3, wherein shot peening is performed on the entire body and the teeth before the shot peening performed on the root of the tooth. The shot peening process performed on the root portion of the teeth consists of a multi-stage shot peening process,
5. The method for manufacturing a disc spring according to claim 3, wherein a diameter of a shot used in a later stage shot peening process is smaller than a diameter of a shot used in a previous stage shot peening process.

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