CN108698201B - Shot peening device - Google Patents

Abstract

A shot peening device (50) is provided with a turntable (79) which rotates around a revolution axis (X1), holding mechanisms (81, 82) which move together with the turntable (79), a pressurizing mechanism (93) which compresses a coil spring (1), a rotation mechanism (100) which rotates the coil spring (1), a blasting mechanism (57) which blasts steel shots to the compressed coil spring (1), load sensors (96, 97) which detect a load applied to the coil spring (1), and a control unit (98). By inputting signals output from the load sensors (96, 97) to the control unit (98), it is possible to detect a change with time in the load applied to the coil spring (1) during shot peening.

Description

A shot peening device

technical field

The present invention relates to a shot peening apparatus that performs shot peening (shot peening hardening) in a state where a coil spring is compressed.

Background technique

In order to improve the durability of coil springs such as suspension springs used in automobile suspension devices, there is known a method of generating compressive residual stress in the coil spring by shot peening. An example of a conventional shot peening apparatus is disclosed in Patent Document 1. This shot peening apparatus ejects steel shot from a centrifugal accelerator (impeller) to the coil spring while conveying the coil spring. A conventional shot peening apparatus is also described in Patent Document 2. This shot peening apparatus compresses the coil spring and performs shot peening in a state where stress is applied thereto. That is, in this shot peening apparatus, a very large compressive residual stress is generated in the coil spring by the shot peening strengthening. Another Patent Document 3 describes an apparatus for performing shot peening while compressing a coil spring on a rotating turntable.

prior art literature

Patent Literature

[Patent Document 1] Patent Publication No. 2002-361558

[Patent Document 2] Patent Publication No. 2003-117830

[Patent Document 3] Patent Publication No. 2015-77638.

SUMMARY OF THE INVENTION

Invention to solve problem

As in Patent Document 1, there is room for improvement in generating a large compressive residual stress in the coil spring in the shot peening apparatus in which only the steel shot is cast on the coil spring. As in Patent Documents 2 and 3, there are apparatuses that perform shot peening in a compressed state of the coil spring. Depending on the shape of the coil spring (especially the shape of the support ring), there are cases where the coil spring is supported in an unstable state. Happening. As a result, due to the instability of the coil spring, there is a possibility that shot peening cannot be properly performed.

Therefore, an object of the present invention is to provide a shot peening apparatus capable of performing shot peening in a state where a desired stress is applied to a coil spring.

way to solve this problem

In one embodiment, the shot peening apparatus is equipped with a turntable mechanism, a revolution mechanism, a holding mechanism, an autorotation mechanism, a pressurization mechanism, a load detector, a spray mechanism, and a control portion, wherein the turntable mechanism includes a turntable that rotates around an orbital axis , the revolving mechanism is used to rotate the turntable mechanism, and the holding mechanism is used to hold the support ring on the lower side of the coil spring and the support ring on the upper side and together with the turntable when the coil spring is erected The rotation mechanism moves about the revolution axis, the rotation mechanism rotates the holding mechanism around the rotation axis, and the pressurization mechanism compresses the coil spring when the coil spring is held in the holding mechanism In the coil spring, the load detector is, for example, a load sensor for detecting a compressive load applied to the coil spring by the pressurizing mechanism, and the ejection mechanism is used for applying the compressed coil to the coil spring. The spring ejects steel shot, and the control unit (for example, a personal computer) detects the change in the load based on the signal output from the load detector.

An example of the load detector is a load sensor, and the load sensor is arranged on a load transmission path between the pressurizing mechanism and the holding mechanism. Moreover, the said control part may have the means which memorize|store the time-dependent change of the said load. Alternatively, the control unit may include a display unit that displays changes in the load over time.

The control unit may be provided with means for notifying when the load exceeds an allowable range while the spraying mechanism sprays the steel shot to the coil spring. Further, the control unit may be provided with a computer program that controls the pressurizing mechanism so that the load may approach a predetermined value while the spraying mechanism sprays the steel shot to the coil spring.

Invention effect

According to the present invention, by subjecting the coil spring to shot peening (shot peening hardening) in a desired state of stress, a compressive residual stress can be formed in the coil spring and a coil spring with stable quality can be obtained.

Description of drawings

FIG. 1 is a perspective view showing an example of a coil spring.

FIG. 2 is a flowchart showing an example of a coil spring manufacturing process.

FIG. 3 is a perspective view schematically showing a first shot peening apparatus.

FIG. 4 is a perspective view showing a part of the transfer device and an example of a transfer mechanism (robot).

5 is a front view of a portion of a second shot peening apparatus according to an embodiment.

FIG. 6 is a longitudinal sectional view of the shot peening apparatus shown in FIG. 5 .

FIG. 7 is a cross-sectional view of the shot peening apparatus shown in FIG. 5 .

FIG. 8 is a perspective view of a lower support base of the shot peening apparatus shown in FIG. 5 .

FIG. 9 is a perspective view of a lower support base of the shot peening apparatus shown in FIG. 5 .

FIG. 10 is a flow chart showing the operation of the shot peening apparatus shown in FIG. 5 .

FIG. 11 is a graph showing an example of a time-dependent change in load generated during shot peening in a certain temperature range.

FIG. 12 is a graph showing another example of a time-dependent change in load generated during shot peening in a certain temperature range.

Symbol Description

1...coil spring, 1a, 1b...support ring, 2...bare wire, 10...1st shot peening device, 50...2nd shot peening device, 52...turntable Mechanism, 55... 1st injection unit, 56... 2nd injection unit, 57... injection mechanism, 61... 1st chamber, 62... 2nd chamber, 79... Turntable , 80...Male shaft mechanism, 81...1st holding mechanism, 82...2nd holding mechanism, 93...Pressure mechanism, 94, 95...Pressure unit, 96, 97... Load cell (load detector), 98...control unit, 100...rotation mechanism, 110...information processing device, 111...input operation unit, 112...display unit, X1... Orbital axis, X2, X3... Rotation axis.

specific embodiment

A coil spring processing apparatus including a shot peening apparatus 50 according to an embodiment will be described below with reference to the drawings of FIGS. 1 to 12 .

FIG. 1 shows an example of the coil spring 1 . The coil spring 1 is made of a bare wire (metal wire) 2 wound in a spiral shape. Support rings 1a and 1b are formed on one end and the other end of the coil spring 1, respectively. Depending on the type of the coil spring 1, the relative positional relationship between the one end tip 1c and the other end tip 1d is constant.

In this specification, the position from the distal end 1c of the coil spring 1 to the position rotated about the axis X1 is referred to as a "position in the coil circumferential direction" or "a position in the winding direction". An example of the coil spring 1 is a cylindrical coil spring, but depending on the structure of the suspension device, various coil springs such as barrel coil springs, hourglass coil springs, conical coil springs, and unequal pitch coil springs may be used. In addition, the support rings 1a and 1b may also have a negative pitch (the pitch angle is negative) or a positive pitch (the pitch angle is positive).

An example of the manufacturing process of the coil spring 1 is shown in FIG. 2 . In the forming step S1 in Fig. 2, the bare wire (metal wire) 2 is wound into a spiral shape by using a winding machine. In the heat treatment step S2, tempering and annealing are performed in order to remove the undesirable stress generated in the bare wire 2 in the molding step S1. For example, after heating the bare wire 2 at about 400 to 450° C., it is gradually cooled.

Furthermore, in the 1st shot peening process S3, the 1st shot peening is performed in a certain temperature range using the residual heat of the heat treatment process S2, for example. In the first shot peening step S3, the entire surface of the coil spring 1 is sprayed with the first steel shot by the first shot peening apparatus 10 shown in FIG. The first steel shot is, for example, shredded wire having a particle size of 1.1 mm. However, the shot peening apparatus 10 other than the above may be used, and the steel shot size (for example, 0.87 to 1.2 mm) other than the above may be used. By the 1st shot peening process S3, a compressive residual stress is formed from the surface of the coil spring 1 to a deep position. And the oxide film (black skin formed by heat processing) formed on the surface of the bare wire 2 is removed by the 1st shot peening process S3.

FIG. 3 schematically shows an example of the first shot peening apparatus 10 . The first shot peening apparatus 10 includes a pair of guide rolls 11 and 12 and a shot ejector (impeller) 13 . A plurality of coil springs 1 are placed on the guide rollers 11 and 12, and are lined up in a row with the axis C1 of each coil spring being the horizontal posture (the posture of falling horizontally). The coil springs 1 on the guide rollers 11 and 12 continuously move in the direction of the arrow F1 while rotating around the axis C1. The steel shot SH1 ejected from the steel shot ejector 13 is ejected toward the moving coil spring 1 .

FIG. 4 shows the transfer device 20 which is part of the coil spring handling device and the robot 21 handling the coil spring 1 . The conveying device 20 continuously conveys the plurality of coil springs 1 in the direction indicated by the arrow F2. The robot 21 supports the coil spring 1 from both sides of the arm 22 by means of an open-close jig 23 provided at the front end of the arm 22 . The robot 21 is an example of a transfer mechanism for moving the coil spring 1 .

The robot 21 has a function of storing the positions of the end tips 1c and 1d of the coil spring 1 supported by the jig 23 in a memory. In order to place the end tips 1c and 1d of the coil spring 1 supported by the robot 21 at predetermined positions, the positions of the end tips 1c and 1d may be restricted in advance by a positioning device such as a jig.

In the second shot peening step S4, the second shot peening (shot peening in a certain temperature range) is performed by the shot peening apparatus 50 shown in FIGS. 5 to 9 . The second shot peening step S4 is performed at a lower temperature (for example, a temperature range of 200 to 250°C) than the first shot peening step S3 while the coil spring 1 is compressed. In the second shot peening step S4 , the second steel shot is sprayed on the entire surface of the coil spring 1 . The size of the second steel shot is smaller than that of the first steel shot used in the first shot peening step S3. The first steel shot is, for example, shreds having a particle size of 0.4 to 0.7 mm. The absolute value of the compressive residual stress in the vicinity of the surface of the bare wire 2 can be increased by the second shot peening step S4.

The solidification step S5 is performed as necessary, the coil spring 1 is coated in the coating step S6, and finally the coil spring 1 is inspected for quality in the inspection step S7.

The configuration and operation of the second shot peening apparatus 50 will be described below with reference to FIGS. 5 to 9 . The second shot peening apparatus 50 constitutes a part of the coil spring processing apparatus. The second shot peening apparatus 50 performs shot peening in a temperature range of, for example, 200 to 250° C. in a posture in which the coil spring 1 is erected. Here, the "posture in which the coil spring 1 is erected" refers to a state in which the axis C1 of the coil spring 1 is substantially vertical.

FIG. 5 is a front view of a part of the second shot peening apparatus 50 . FIG. 6 is a longitudinal cross-sectional view of the second shot peening apparatus 50 . FIG. 7 is a cross-sectional view of the second shot peening apparatus 50 . The second shot peening apparatus 50 includes a casing 51, a turntable mechanism 52, a spray mechanism 57 (shown in Fig. 6 ), a first elevating mechanism 58 and a second elevating mechanism 59. The spray mechanism 57 includes a first spray unit 55 and a second spray unit 56 . The first elevating mechanism 58 and the second elevating mechanism 59 move the ejection units 55 and 56 in the vertical direction.

The first elevating mechanism 58 and the second elevating mechanism 59 are respectively composed of servo motors 58a, 59a and ball screws 58b, 59b, and the rotation of the servo motors 58a, 59a is controlled by a controller. These elevating mechanisms 58 and 59 independently move the injection units 55 and 56 in the vertical direction by predetermined strokes Y1 and Y2 according to the rotation direction and rotation degree of the servo motors 58a and 59a.

As shown in FIGS. 6 and 7 , a first chamber 61 , a second chamber 62 , and intermediate chambers 63 and 64 located between the first chamber 61 and the second chamber 62 are formed inside the casing 51 . . A coil spring inlet 65 is formed in the first chamber 61 . The coil spring inlet 65 is an opening for inserting or extracting the coil 1 into the first chamber 61 from the outside of the case 51 . In the 2nd chamber 62, the injection port 55a of the 1st injection unit 55 and the injection port 56a of the 2nd injection unit 56 are arrange|positioned. The steel shot SH2 is ejected toward the coil spring 1 from these ejection ports 55a and 56a.

As shown in FIG. 7 , partition walls 70 and 71 are provided between the first chamber 61 and the intermediate chambers 63 and 64 . The partition walls 72 and 73 cannot be provided between the second chamber 62 and the intermediate chambers 63 and 64 . Sealing walls 74 and 75 are formed on the intermediate chambers 63 and 64 . The sealing walls 74 and 75 can prevent the shot SH2 injected into the second chamber 62 from going toward the first chamber 61 .

The turntable 52 shown in FIG. 5 includes a turntable 79 , a revolution mechanism 80 (shown in FIG. 5 ), a first holding mechanism 81 and a second holding mechanism 82 . The turntable 79 rotates around an axis X1 that revolves in the vertical direction. The revolution mechanism 80 is equipped with a motor. The motor rotates the turntable 79 intermittently and alternately by 180° C. in the first direction R1 and the second direction R2 (shown in FIG. 7 ) around the revolution axis X1 . The holding mechanisms 81 and 82 rotate together with the turntable 79 around the revolution axis X1. The first holding mechanism 81 has a lower support seat 81a and an upper support seat 81b. The lower support base 81 a is arranged on the turntable 79 . The upper support base 81b is arranged above the lower support base 81a. The second holding mechanism 82 also has a lower support seat 82a and an upper support seat 82b. The lower support base 82 a is arranged on the turntable 79 . The upper support base 82b is arranged above the lower support base 82a.

The first holding mechanism 81 and the second holding mechanism 82 are arranged at rotationally symmetrical positions of 180° C. with respect to the revolution axis X1 . Support plates 83 and 84 are arranged behind the first holding mechanism 81 and the second holding mechanism 82 on the turntable 79 (as shown in FIG. 7 ).

The lower support seat 81a of the first holding mechanism 81 and the lower support seat 82a of the second holding mechanism 82 are provided with clamps 85 for preventing positional displacement, respectively. The lower support ring 1 a of the coil spring 1 can be fitted into the preventing jig 85 . 8 and 9 show the first holding mechanism 81 and the lower support base 81a. The configuration of the lower support base 82 a of the second holding mechanism 82 is the same as that of the lower support base 81 a of the first holding mechanism 81 . Therefore, the lower support seat 81a of the first holding mechanism 81 will be described with reference to FIGS. 8 and 9 .

As shown in FIGS. 8 and 9 , the lower support base 81a is provided with a jig 85 for preventing positional displacement. The jig 85 for preventing positional displacement has a plurality of (eg, three) claw members 85a, 85b, and 85c. The claw members 85a, 85b, and 85c are arranged according to the shape, pitch angle, etc. of the support ring 1a so that the support ring 1a of the coil spring 1 can be stably supported. For example, the claw members 85a, 85b, and 85c are arranged at equal intervals (eg, 90°) in the circumferential direction of the lower support base 81a. In addition, the number of claw members of the lower positional displacement preventing jig 85 and the number of the claw members of the upper positional displacement preventing jig 91 may be other than three, respectively. Also, the claw members may be arranged at other pitches than 90°.

The disk-shaped base member 86 is formed with guide grooves 86a, 86b. The claw members 85a, 85b, 85c are movable along the guide grooves 86a, 86b. After the claw members 85a, 85b, 85c are adjusted to the corresponding positions of the support ring 1a, the claw members 85a, 85b, 85c are fixed to the base member 86 by bolts 87 (shown in FIG. 9). Height adjustment members 88 and 89 are provided between the base member 86 and the claw members 85b and 85c. The height adjustment members 88, 89 are provided with thicknesses T1, T2 corresponding to the pitch angles of the support rings of the coil springs. Through the above operations, the support rings of the negative pitch can also be securely placed on the claw members 85a, 85b, and 85c. The claw members 85a, 85b, and 85c are respectively formed with V-grooves 90 into which the support ring 1a is inserted.

The upper support bases 81b and 82b are provided with a jig 91 for preventing the positional displacement of the upper support ring 1b. The upper misalignment preventing jig 91 has a plurality (for example, three) of claw members corresponding to the shape or pitch angle of the support ring 1b, like the lower misalignment preventing jig 85. These claw members hold the upper support ring 1b in a stable state. The upper jig 91 for preventing positional displacement may have a different shape from the lower jig 85 for preventing positional displacement depending on the shape of the support ring 1b.

The revolution mechanism 80 (shown in FIG. 5 ) rotates the turntable 79 around the revolution axis X1. That is, the revolution mechanism 80 rotates the turntable 79 alternately by 180° in the first direction R1 and the second direction R2 (shown in FIG. 7 ) intermittently. When the first holding mechanism 81 is located at the position of the first chamber 61 , the second holding mechanism 82 is located at the position of the second chamber 62 . When the second holding mechanism 82 is located at the position of the first chamber 61 , the first holding mechanism 81 is located at the position of the second chamber 62 .

Furthermore, as shown in FIG. 5 , the shot peening apparatus 50 is equipped with a pressing mechanism 93 for compressing the coil spring 1 . The pressing mechanism 93 includes pressing units 94 and 95 that move the upper support bases 81b and 82b in the vertical direction. An example of the pressing units 94 and 95 is composed of a ball screw and a servo motor. The pressing units 94 and 95 can change the compressive load (stress) applied to the coil spring 1 according to the degree of movement of the upper support bases 81b and 82b in the vertical direction. Other examples of the pressurizing units 94 and 95 using fluid pressure as a drive source, such as a hydraulic cylinder, may also be used.

The first pressurizing unit 94 and the second pressurizing unit 95 are provided with load cells 96 and 97, respectively. These load sensors 96 and 97 are examples of load detectors. The load sensors (load detectors) 96 and 97 are used to detect the compressive load applied to the coil spring 1 during shot peening, and input an electrical signal related to the detected compressive load to the control unit 98 . The first load sensor 96 is arranged on the load transmission path between the first pressurizing unit 94 and the upper support base 81b. The second load sensor 97 is arranged on the load transmission path between the second pressurizing unit 95 and the upper support base 82b.

The control unit 98 has a function (computer program) for detecting a change in load based on the outputs of the load sensors 96 and 97 . In addition, the control unit 98 has a function of notifying when the load during shot peening exceeds the allowable range. Furthermore, the control unit 98 compares the load values output from the load sensors 96 and 97 with a predetermined load value set in the control unit 98 in advance. Furthermore, it has a control function of feeding back a signal to the first pressurizing unit 94 and the second pressurizing unit 95 so that the load value output by the load sensors 96 and 97 and the load value set in the control unit 98 are equal to each other. The difference is close to zero, that is to say, the coil spring 1 is loaded with a predetermined load as much as possible.

This shot peening apparatus 50 has an autorotation mechanism 100 . The autorotation mechanism 100 is used to autorotate the coil spring 1 around the autorotation axes X2 and X3. The rotation axes X2 and X3 respectively extend in the vertical direction. The autorotation mechanism 100 includes a lower rotating part 101 and an upper rotating part 102 . The lower rotating part 101 is used to rotate the lower support bases 81a and 82a around the rotation axes X2 and X3. The upper rotation part 102 is used to rotate the upper support bases 81b and 82b around the rotation axes X2 and X3.

The lower-side rotating part 101 and the upper-side rotating part 102 have a timing belt and a drive source such as a servo motor, respectively. The control unit 98 for controlling the driving source rotates the lower rotating unit 101 and the upper rotating unit 102 by the same number of rotations in the same direction in synchronization with each other. That is, the lower side support bases 81a and 82a and the upper side support bases 81b and 82b are rotated in the same direction by the same number of rotations in synchronization with each other. Further, the lower support bases 81a, 82a and the upper support bases 81b, 82b can be stopped at the first rotation stop position or the second rotation stop position set in advance based on data input to the control unit 98 in advance. An example of the first rotation stop position is a position suitable for the robot 21 to transfer the coil spring 1 to the holding mechanisms 81 and 82 . An example of the second rotation stop position is a position suitable for taking out the coil spring 1 from the holding mechanisms 81 and 82 .

An information processing apparatus 110 such as a personal computer is connected to the control section 98 . The information processing apparatus 110 has an input operation unit 111 and a display unit 112 and a pointing device 113 such as a mouse, into which the product number of the coil spring and various data can be input. For example, various data related to the coil spring (coil diameter, number of coils, length, wire diameter) or data related to the load applied to the coil spring during shot peening can be input through the input operation unit 111 or the storage medium 114. .

The information processing device 110 such as a personal computer is also used to store the temporal change of the load applied to the coil spring 1 during shot peening. Further, the display unit 112 of the information processing apparatus 110 is used to display the temporal change of the load during shot peening. In addition, the information processing device 110 may also include the control unit 98 .

FIG. 7 is a plan view of the cross section of the first spray unit 55 and the second spray unit 56 . The first injection unit 55 is equipped with an impeller (turbine) 121 and a distributor 122 . The impeller 121 is rotated by the motor 120 . The distributor 122 is used to supply the steel shot SH2 to the impeller 121 . The second injection unit 56 also includes an impeller 126 rotated by a motor 125 and a distributor 127 that supplies the steel shot SH2 to the impeller 126.

The first spray unit 55 is movable in the up-down direction along the guide member 130 extending in the up-down direction. The guide member 130 is provided on the side of the housing 51 . The first ejection unit 55 reciprocates between an ascending position A1 and a descending position B1 separated by the intermediate position N1 based on the first elevating mechanism 58 (shown in FIG. 6 ). The second ejection unit 56 may move in the up-down direction along the guide member 131 extending in the up-down direction. The guide member 131 is provided on the side of the housing 51 . The second ejection unit 56 reciprocates between the ascending position A2 and the descending position B2 separated by the intermediate position N2 based on the second elevating mechanism 59 (shown in FIG. 8 ).

FIG. 10 is a flowchart showing the operation of the shot peening apparatus 50 of the present embodiment.

In step S10 in FIG. 10 , the lower support seat 81 a of the first holding mechanism 81 is stopped in the first chamber 61 . The first coil spring 1 is placed (mounted) on the lower support base 81a by the robot 21 (as shown in FIG. 4). The support ring 1a placed on the lower support base 81a is stopped by a jig 91 (shown in FIGS. 8 and 9 ) for preventing displacement. The coil spring 1 between the lower support base 81a and the upper support base 81b is compressed by the descending of the upper support base 81b. At this time, the second holding mechanism 82 is located in the second chamber 62 . The state of the second holding mechanism 82 is an empty state in which the coil spring is not mounted. The coil spring 1 on the left in FIG. 5 is in a free state where no compressive load is applied. The length (free length) of the coil spring 1 in the free state is L1. The coil spring 1 on the right side in FIG. 5 shows a state compressed to the length L2.

In step S11 in FIG. 10 , the turntable 79 is rotated by 180° in the first direction. By this rotation, the coil spring 1 held by the first holding mechanism 81 is sent into the second chamber 62 . At the same time, the second holding mechanism 82 moves to the first chamber 61 . In step S12 , the second coil spring 1 is installed in the second holding mechanism 82 .

In step S13 , in the second chamber 62 , the first coil spring 1 in the compressed state is subjected to shot peening while being rotated (rotated) by the autorotation mechanism 100 . That is, SH2 is injected to the 1st coil spring 1 by the 1st injection unit 55 and the 2nd injection unit 56 which move in an up-down direction. Since the shot peening is performed in a stressed state, a compressive residual stress that effectively improves the durability of the coil spring 1 can be formed on the surface layer portion of the coil spring 1 .

In step S14, the turntable 79 is rotated by 180° in the second direction. By this rotation, the coil spring 1 held by the first holding mechanism 81 is returned to the first chamber 61 . Then, the coil spring 1 held by the second holding mechanism 82 is sent into the second chamber 62 .

In step S15, the upper support seat 81b of the first holding mechanism 81 is raised. Then, the first coil spring 1 held by the first holding mechanism 81 is taken out by the robot 21 . The third coil spring 1 is installed in the empty first holding mechanism 81 by the robot 21 . Then, the coil spring 1 is compressed by the lowering of the upper support base 81b.

In step S16 , in the second chamber 62 , the second coil spring 1 in the compressed state is subjected to shot peening while being rotated (rotated) by the autorotation mechanism 100 . That is, SH2 is injected to the 2nd coil spring 1 by the 1st injection unit 55 and the 2nd injection unit 56 which move in an up-down direction.

In step S17, the turntable 79 is rotated again by 180° in the first direction. By this rotation, the coil spring 1 held by the first holding mechanism 81 is returned to the second chamber 62 , and the second holding mechanism 82 is returned to the first chamber 61 . The upper support base 82b of the second holding mechanism 82 is raised. Then, the coil spring 1 held by the second holding mechanism 82 is taken out by the robot 21 . The next coil spring 1 is installed in the empty second holding mechanism 82 by the robot 21 . Then, the coil spring 1 is compressed by the lowering of the upper support base 82b. This series of steps S10 to S17 is repeated according to the number (N) of the coil springs 1 , and the shot peening of all the coil springs 1 is completed.

FIG. 11 is a schematic diagram showing an example of a time-dependent change (relationship between time and load) of the load generated during shot peening strengthening by the shot peening apparatus 50 in a certain temperature range. For example, when the coil spring 1 held by the first holding mechanism 81 is shot peened within a certain temperature range by the shot peening apparatus 50 , the coil spring 1 is gradually compressed by the pressurizing mechanism 93 . Since the interval from time t0 to t1 is the non-sensing zone of the load sensor 96, no load is detected. However, after the non-sensing zone is exceeded, the coil spring 1 is further compressed, and the load detected by the load sensor 96 increases from Z1 to Z2. At time t2, once the target load Z2 is reached, the pressing mechanism 93 is stopped. Then, in a state in which the compression amount (compression stroke) of the coil spring 1 is kept constant, shot peening strengthening (shot peening SH2 ) is performed in a constant temperature range from time t3 . The shot peening strengthening performed in this certain temperature range is performed until time t4.

Once the compressive residual stress is generated in the coil spring 1 by shot peening in a certain range, the load tends to increase slightly due to the influence of the compressive residual stress, as indicated by the one-dot chain line m1 in FIG. 11 . . However, in this temperature region, since the function of the compressed coil spring 1 is degraded, the load is significantly reduced as indicated by the broken line m2. Therefore, the total load, as shown by the solid line m3, tends to decrease slightly. This total load (solid line m3) is determined by taking into account the increase in load (solid line m1) due to the generation of compressive residual stress and the decrease in load (solid line m2) due to "deterioration" in the coil spring 1 . Therefore, the total load (solid line m3) may also increase.

In the shot peening apparatus 50 of the present embodiment, the control unit continuously monitors the loads detected by the load sensors 96 and 97 during shot peening hardening within a certain temperature range. Then, information related to the detected load is displayed on the display unit 112 . At the same time, the information is stored in the memory or storage medium 114 of the information processing device 110 . Information (time-dependent changes in load, etc.) stored in the storage medium 114 or the like can be retrieved at any time as needed. When the detected load change is within the allowable range, it is determined that shot peening in an accurate constant temperature range has been performed in a state where a predetermined load is applied to the coil spring.

As described above, during shot peening in a certain temperature range by the shot peening device 50 , the data related to the temporal change of the load is stored in the built-in memory or the storage medium 114 of the information processing device 110 in advance. Through the above operations, it is possible to ensure that shot peening in a certain temperature range is correctly applied to the coil spring, that is, to ensure quality.

The "decay" of the coil spring that occurs during shot peening can be a problem. In this case, as indicated by the two-dot chain line m4 in FIG. 11 , the signals output from the load sensors 96 and 97 are fed back to the pressing mechanism 93 so that the load changes during shot peening strengthening in a certain temperature range. be constant. Then, by driving the pressurizing units 94, 95 in real time and changing the compression stroke, shot peening in a certain temperature range is performed under a substantially constant compression load.

FIG. 12 is a schematic diagram showing another example of the time-dependent change of the load generated during shot peening in a certain temperature range. As shown by the solid line m5 in FIG. 12, there is a case where the load suddenly falls outside the allowable range (threshold value) at time t5. In this case, the coil spring during shot peening may be detached from the first holding mechanism 81 or the second holding mechanism 82 . Therefore, when such a sudden drop in the load is confirmed, it is determined that the shot peening strengthening within a certain temperature range is not properly performed, and the coil spring is treated as a defective product.

Furthermore, as indicated by the broken line m6 in FIG. 12 , when the load during shot peening changes periodically, it is considered that the coil spring 1 is kept in an unstable state. Therefore, even when the load change like the above was confirmed, it was judged that shot peening in a certain temperature range was not properly performed, and the coil spring was treated as a defective product.

Industrial availability

When carrying out this invention, it cannot be overemphasized that the form, structure, arrangement|positioning, etc. of each element which comprises a shot peening apparatus can be changed and implemented. For example, a personal computer may be used as a control unit that processes a signal output from a load cell, or an information processing device that stores a computer program specially developed for use in a shot peening apparatus may be used. Also, a load detector other than the load cell may be used.

Claims (6)

1. A shot peening device, characterized in that it is equipped with: a turntable mechanism (52), the turntable mechanism (52) comprising a turntable (79) centered on a revolving axis (X1); a revolution mechanism (80), the revolution mechanism (80) is used to rotate the turntable mechanism (52); a holding mechanism (81, 82) for holding the lower support ring (1a) and the upper support ring (1b) of the coil spring (1) in an upright posture, and move together with the turntable (79) around the revolution axis (X1); A rotation mechanism (100), the rotation mechanism (100) is used to rotate the holding mechanism (81, 82) around the rotation axis (X2, X3); a pressing mechanism (93) for compressing the coil spring (1) when the coil spring (1) is held in the state of the holding mechanisms (81, 82); a load detector, which is used for detecting the load on the coil spring (1) through the pressing mechanism (93); a spraying mechanism (57), the spraying mechanism (57) is used for spraying the steel shot on the compressed coil spring (1); a control part (98), the control part (98) is configured to detect the change of the load based on the output signal of the load detector; The control unit (98) includes means for storing the temporal change of the load. 2 . The shot peening apparatus according to claim 1 , wherein the load detector is a load transmission path arranged between the pressing mechanism ( 93 ) and the holding mechanism ( 81 , 82 ). 3 . on the load sensor. 3 . The shot peening apparatus according to claim 1 , wherein the control unit ( 98 ) includes a display unit ( 112 ) that displays a time-dependent change of the load. 4 . 4 . The shot peening apparatus according to claim 2 , wherein the control unit ( 98 ) includes a display unit ( 112 ) that displays a time-dependent change of the load. 5 . 5. The shot peening apparatus according to claim 1 or 2, characterized in that, the control part (98) is equipped with a A device that notifies when the load exceeds the allowable range. 6. The shot peening apparatus according to claim 1 or 2, characterized in that, the control unit (98) controls the control unit (98) during the period when the spray mechanism (57) sprays steel shot to the coil spring (1). The pressurizing mechanism (93) works so that the load is close to a predetermined value.

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