A method for assembling a powder metallurgy brake pad of a motor train unit by riveting

Abstract

The application provides a motor train unit powder metallurgy brake pad spin riveting assembly method, and solves the problem of too large gap difference between a friction body and a steel back caused by manual riveting assembly of a powder metallurgy brake pad, and low yield rate. The technical scheme is as follows: a brake pad assembly riveting tool body is surrounded by a cover plate, a side wall template and a bottom gasket, and a strip-shaped limiting plate for keeping a gap between the steel back and the friction body formed by a disc spring elastic support is supported between the template and the cover plate; the assembly steps include: brake pad assembly position placement, brake pad assembly riveting tool body combination, riveting positioning mechanism positioning, spin riveting of the rivets positioned by using a riveting machine, again pressing the riveting positioning mechanism pressing rod, and then sequentially completing the remaining rivet installation, and finally completing the spin riveting assembly of the brake pad assembly, which ensures the uniform gap between the friction body and the steel back, is easy to operate, has low manufacturing cost, and is suitable for manual rapid assembly operation.

Description

Technical Field

[0001] This invention relates to the field of brake pad assembly technology, and in particular to a method for riveting and assembling powder metallurgy brake pads for high-speed trains, which is applicable to the riveting and assembly of small batches of powder metallurgy brake pads. Background Technology

[0002] Currently, my country's high-speed railway locomotive technology is developing rapidly. As railway trains move towards higher speeds and heavier loads, stricter requirements are being placed on various locomotive performance aspects. The performance of the brake pads in the braking system has a significant impact on the train's braking effect. Among these, the powder metallurgy brake pads used in high-speed trains are a key component of the braking system. These brake pads are assembled by riveting multiple friction elements and disc springs onto the same steel backing. For example, a powder metallurgy brake pad consists of a steel backing, nine friction elements, nine disc springs, and nine rivets. The rivets pass through the friction elements, disc springs, and steel backing, and are assembled as a single unit through a riveting process. To reduce the likelihood of uneven wear, a certain gap should be left between the friction elements and the steel backing after riveting. This allows the friction elements to shift along the rivet direction, giving the product an elastic floating function. The friction element shifting process: When the friction element surface is subjected to force, it can move along the rivet direction; when the external force is unloaded, the friction element returns to its original position along the rivet direction through the spring force of the disc spring. In the small-batch manufacturing stage of powder metallurgy brake pads, manual riveting assembly is typically used. The operator inserts a rivet through the corresponding friction element, disc spring, and steel backing, using both hands to hold the assembly on a CJW-3000A riveting machine for one-to-one riveting. Then, the next set of rivets, friction elements, and disc springs are assembled and riveted to the steel backing, repeating this riveting process multiple times. During riveting, the unstable force direction on the disc spring often results in excessively large gap differences between the friction element and the steel backing, affecting the quality of the finished product and causing a low yield. While some large-scale production of powder metallurgy brake pads uses CNC riveting equipment, which improves the yield, this equipment is expensive, complex in construction, and has high maintenance costs, making it unsuitable for small-scale production. Summary of the Invention

[0003] The purpose of this invention is to provide a method for riveting and assembling powder metallurgy brake pads for high-speed trains. This method solves the problem of excessive gap differences between the friction body and the steel backing, resulting in low yield, caused by manual riveting assembly of powder metallurgy brake pads. It ensures uniform gap between the friction body and the steel backing, is easy to operate, has low manufacturing costs, and is suitable for rapid manual assembly.

[0004] The technical solution adopted in this invention is as follows: the steps of the powder metallurgy brake pad riveting assembly method for high-speed trains include: using a brake pad assembly riveting fixture body, a bracket, and a riveting positioning mechanism as the riveting fixture. The brake pad assembly riveting fixture body is a box-shaped clamping device formed by a cover plate, a template on the side wall, and a pad at the bottom, and fixed with bolts. The cover plate is provided with multiple riveting pressure head insertion holes corresponding to the friction body mounting holes of the steel back. A strip-shaped limiting plate is supported between the template and the cover plate to maintain a gap formed by the elastic support of the disc spring between the steel back and the friction body. Multiple positioning pins corresponding to the riveting pressure head insertion holes are inserted into the pad. The positioning pins are movably inserted and supported on the positioning pin mounting holes by the lower support platform and the end insertion pins. A groove communicating with the positioning pin mounting holes is provided on the lower surface of the pad. The groove is a continuous zigzag groove that gradually connects from the positioning pin mounting hole in the center of the pad to the outer positioning pin mounting holes. The zigzag groove has a groove inlet and a groove outlet at the edge of the pad.

[0005] The bracket consists of an upper support plate with a central through hole and two equal-height support columns on both sides;

[0006] The brake pad assembly riveting fixture body is matched with a riveting positioning mechanism. The riveting positioning mechanism includes a positioning plate set on the base of the riveting machine, a positioning sleeve set on the upper end of the positioning plate, and a central shaft that slides through the positioning sleeve using a compression spring in the central cavity of the positioning plate. A pressure rod is connected to the outside of the central shaft.

[0007] Step 1: Positioning of the brake pad assembly. First, insert all the positioning pins corresponding to the brake pad assembly into the positioning pin mounting holes on the pad. Then, place the corresponding rivets on the upper end of the positioning pins. Next, align the corresponding friction bodies and disc springs with the rivets and install them on the positioning pins in sequence. Place the steel backing above the rivets, align the friction body mounting holes of the steel backing with the rivets, and place it on the disc spring 7 through the rivets. Leave a gap between the steel backing and all the friction bodies, formed by the elastic support of the disc springs. This completes the positioning of the brake pad assembly.

[0008] Step 2: Assemble the brake pad assembly riveting fixture body, fasten the cover plate onto the steel back and limit plate, and connect and fix it to the template with screws;

[0009] Step 3: Positioning the riveting positioning mechanism. Fix the riveting positioning mechanism on the base of the riveting machine and place it under the bracket. Align the riveting machine pressure head with the central shaft of the riveting positioning mechanism vertically. The upper end of the central shaft should protrude from the central through hole of the upper bracket. Then place the assembled brake pad assembly riveting fixture body on the bracket. Connect the sliding groove inlet on the bottom of the pad with the upper end of the central shaft. Press the pressure rod of the riveting positioning mechanism. The compression spring will contract under force, and the central shaft will move downward and retract into the sliding groove. Push the brake pad assembly riveting fixture body to slide along the sliding groove of the pad on the bracket. Release the pressure rod so that the positioning pin mounting hole in the center of the pad slides to the position of the central shaft. The central shaft will spring upward and the upper end of the central shaft will be inserted into the positioning pin mounting hole in the center of the pad. The riveting machine pressure head is now aligned with the riveting pressure head insertion hole in the center of the cover plate, completing the positioning.

[0010] Step 4: Use a riveting machine to rivet and fix the positioned rivets;

[0011] Step 5: Press the riveting positioning mechanism lever again to push the combined brake pad assembly riveting fixture body along the slide groove of the pad to the next positioning pin mounting hole. Switch the riveting position, release the lever, and let the positioning pin mounting hole slide to the center shaft position. The upper end of the center shaft is inserted into the positioning pin mounting hole of the pad. The riveting machine head is aligned with the riveting head insertion hole in the center of the cover plate. Then use the riveting machine to rivet and fix the positioned rivets. Repeat the above riveting process, and then install the remaining rivets one by one to finally complete the riveting assembly of the brake pad assembly.

[0012] The advantages and positive effects of this invention are as follows: The brake pad assembly riveting fixture body used in this EMU powder metallurgy brake pad assembly method is a box-shaped clamping device composed of a cover plate, a template, and a pad. A limiting plate is supported between the template and the cover plate. This limiting plate maintains a gap between the steel back and the friction body, formed by the elastic support of the disc springs. Therefore, during the assembly process, the upward support of the limiting plate and the downward gravity of the cover plate ensure that the steel back and the friction body maintain the same gap during riveting. This avoids the problem of inconsistent gaps between the steel back and the friction body caused by the riveting operator manually adjusting the pressure of each disc spring, which would negatively impact the quality of the finished product. The gap between the steel back and the friction body can be adjusted by changing the thickness of the limiting plate, flexibly adjusting the elastic floating function of the powder metallurgy brake pad. Furthermore, the brake pad assembly riveting fixture body allows for the unified riveting of all friction bodies, disc springs, and rivets after they have been arranged in their riveting positions, improving the efficiency of the riveting installation. The system employs a pad, bracket, and riveting positioning mechanism in conjunction with a chute featuring connecting positioning post mounting holes. The chute is a continuous, zigzag-shaped chute that gradually connects to the positioning post mounting holes at the center of the pad, preventing shifts in the center of gravity caused by changes in the riveting position and thus affecting the gap. The zigzag-shaped chute has a chute inlet and outlet connected at the edge of the pad, enabling rapid and accurate displacement of the brake pad assembly riveting fixture body on the bracket. The riveting pressure head insertion holes are quickly aligned with the riveting pressure head of the riveting machine for riveting and pressing. Therefore, the brake pad assembly riveting fixture body can be used to arrange all friction elements, disc springs, and rivets in their riveting positions before riveting, improving riveting installation efficiency. It ensures a uniform gap between the friction elements and the steel backing, greatly improving the product quality of powder metallurgy brake pads for high-speed trains. The system has a simple structure, low manufacturing cost, and is suitable for rapid manual operation. Attached Figure Description

[0013] The present invention will be further described below with reference to the accompanying drawings.

[0014] Figure 1 This is a schematic diagram of the overall structure of the riveting fixture used in this embodiment of the invention;

[0015] Figure 2 This is a schematic diagram of the structure of the riveting fixture body for the brake pad assembly used in this invention;

[0016] Figure 3 yes Figure 2 Top view;

[0017] Figure 4 This is a perspective view of the bottom of the pad used in this invention;

[0018] Figure 5 This is a schematic diagram of the bracket structure used in this invention;

[0019] Figure 6This is a schematic diagram of the riveting positioning mechanism used in this invention;

[0020] Figure 7 This is an exploded structural diagram of the initial state of the assembly process of the present invention;

[0021] Figure 8 This is a structural schematic diagram of the assembly state of the present invention;

[0022] Figure 9 yes Figure 8 A schematic diagram of the structure of the riveting fixture body of the brake pad assembly in the state of displacement;

[0023] Figure 10 yes Figure 8 Enlarged view of part A;

[0024] Figure 11 yes Figure 8 BB-direction sectional view;

[0025] Figure 12 This is a schematic diagram of the brake pad structure after riveting according to the present invention.

[0026] Explanation of the numbers in the diagram: 1. Brake pad assembly riveting fixture body; 2. Bracket; 3. Riveting positioning mechanism; 4. Riveting machine base; 5. Positioning column; 6. Steel back; 7. Disc spring; 8. Friction body; 9. Rivet; 10. Riveting machine pressure head; 11. Cover plate; 12. Limiting plate; 13. Template; 14. Pad; 15. Riveting pressure head insertion hole; 16. M10 socket head cap screw; 17. M5 countersunk screw, 18 positioning post mounting hole, 19 slide groove, 20 clearance, 21 upper support plate, 22 equal height support column, 23 center through hole, 31 pressure rod, 32 center shaft, 33 positioning sleeve, 34 compression spring, 35 positioning plate, 51 positioning post support platform, 52 end plug-in post, 181 center positioning post mounting hole, 182 second positioning post mounting hole, 183 third positioning post mounting hole, 184 fourth positioning post mounting hole, 185 fifth positioning post mounting hole, 186 sixth positioning post mounting hole, 187 seventh positioning post mounting hole, 188 eighth positioning post mounting hole, 189 ninth positioning post mounting hole, 191 slide groove inlet, 192 slide groove outlet. Detailed Implementation

[0027] According to the appendix Figure 1-12 The assembly method of the present invention is described in detail. An example is a method for riveting powder metallurgy brake pads in high-speed trains. Figure 1 As shown, this is the riveting fixture used in this assembly method, suitable for assembling multiple friction elements onto a powder metallurgy brake pad on a steel back. It includes: a brake pad assembly riveting fixture body 1, a bracket 2, and a riveting positioning mechanism 3, all placed on a riveting machine base 4 for operation. Figure 2As shown, the brake pad assembly riveting fixture body is a box-shaped clamping device formed by a top cover plate 11, a side template 13, and a bottom pad plate 14. Figure 3 As shown, the cover plate 11 has nine riveting head insertion holes 15 corresponding to the friction body mounting holes of the steel backing. The template 13 is formed by the surrounding side wall plates. A strip-shaped limiting plate 12 supports the upper end face of the template and the cover plate. The cover plate 11 is connected and fixed to the template 13 by M10 hexagon socket screws 16. The enclosed internal cavity has a certain height dimension, so that the brake pad assembly has a certain preload. The limiting plate 12 is connected and fixed to the template 13 by M5 countersunk screws 17. The limiting plate has a certain height, such as... Figure 9 and Figure 10 As shown, a gap 20, formed by the elastic support of a disc spring, is maintained between the riveted steel back 6 and the friction body 8. The gap width between the friction body and the steel back is h = 0.7 ± 0.05 mm. Figure 2 and Figure 4 As shown, the pad 14 is fixed to the lower part of the template 13 by M6 hexagonal screws. The pad 14 is provided with nine positioning post mounting holes 18 corresponding to the riveting head insertion holes 15. Positioning posts 5 are inserted into the positioning post mounting holes 18. The lower part of the positioning post is provided with a positioning post support platform 51 and an end insertion post 52. The support platform and the end insertion post are movably inserted and supported on the positioning post mounting holes 18. The positioning post mounting holes and the end insertion posts adopt H7 / m6 transition fit respectively. The lower surface of the pad is a smooth surface and is provided with a 6mm wide and 2.5mm deep groove 19. The groove connects the nine positioning post mounting holes 18. The main function is to facilitate the displacement of the brake pad assembly riveting fixture body and the switching of the mounting hole positioning points. More specifically, the chute can be constructed by gradually connecting the central positioning post mounting hole 181 located in the center of the pad to the outer positioning post mounting holes to form a continuous zigzag chute. To facilitate installation, the positioning post mounting hole positions can be marked with installation serial numbers, and a chute inlet 191 and a chute outlet 192 connecting the chute 19 are provided on the edge of the pad 14.

[0028] like Figure 1 and Figure 5 As shown, the bracket 2 is fixed on the riveting machine base 4. The bracket consists of an upper support plate 21 and two equal-height support columns 22 on both sides. The upper support plate and the equal-height support columns are connected by M6 hexagon socket screws. The upper support plate 21 has a central through hole 23 in the middle for clearance. The central shaft of the riveting positioning mechanism 3 can slide into the groove 19 of the pad plate 14 and the positioning column mounting hole 18 through the central through hole 23 of the upper support plate, thus playing a role in positioning the riveting fixture.

[0029] The brake pad assembly riveting fixture body is equipped with a riveting positioning mechanism, such as... Figure 6As shown, the riveting positioning mechanism is mainly assembled from a positioning plate 35, a central shaft 32, a pressure rod 31, a positioning sleeve 33, and a compression spring 34. The positioning plate 35 is set on the base of the riveting machine with an transition fit. A longitudinal central cavity is set inside the positioning plate 35. The upper end is connected and fixed to the positioning sleeve 33 by an M5 hexagonal screw. The central shaft 32, which slides through the positioning sleeve, is set inside the central cavity of the positioning plate by the compression spring 34. The central shaft 32 is connected to a horizontally placed pressure rod 31. The pressure rod is a round bar-shaped wrench that passes through the positioning sleeve and is connected to the central shaft, providing a power source for the up and down movement of the central shaft.

[0030] like Figures 8 to 11 As shown, the specific steps of the powder metallurgy brake pad riveting assembly method for this EMU are as follows:

[0031] Step 1: Positioning of the brake pad assembly. First, insert the nine positioning pins 5 into the positioning pin mounting holes 18 of the pad 14. Then, place the nine rivets 9 on the upper end of the positioning pins respectively. Next, align the nine friction bodies 8 and the nine disc springs 7 with the nine rivets and install them onto the positioning pins in sequence. Align the friction body mounting holes on the steel back 6 with the nine rivets and place them on the disc springs 7 through the rivets. Leave a gap between the steel back and all the friction bodies, formed by the elastic support of the disc springs, to complete the positioning of the brake pad assembly.

[0032] Step 2: Assemble the brake pad assembly riveting fixture body, fasten the cover plate 11 onto the steel back 6 and the limit plate, and connect and fix it to the template using M10 internal hexagonal screws.

[0033] Step 3: Positioning the riveting positioning mechanism. Fix the riveting positioning mechanism on the riveting machine base 4 and place it under the bracket. At this time, the riveting machine pressure head 10 is aligned vertically with the central shaft 32 of the riveting positioning mechanism. The upper end of the central shaft 32 protrudes from the central through hole 23 of the upper bracket. Then, place the assembled brake pad assembly riveting fixture body on the bracket 2. Use the sliding groove inlet 191 on the bottom surface of the pad 14 to connect with the upper end of the central shaft 32 of the riveting positioning mechanism that protrudes from the central through hole 23 of the upper bracket. The operator presses the riveting positioning mechanism pressure rod 31, and the compression spring is compressed. The central shaft 32 moves downward and retracts into the sliding groove, pushing the brake pad assembly riveting fixture body to slide along the sliding groove of the pad on the bracket. The operator can release the pressure rod, so that the positioning pin mounting hole 181 in the center of the pad slides to the position of the central shaft. The central shaft springs up. At this time, the upper end of the central shaft is inserted into the positioning pin mounting hole in the center of the pad. The riveting machine pressure head is aligned with the riveting pressure head insertion hole in the center of the cover plate, and the positioning is completed.

[0034] Step 4: Use a riveting machine to rivet and fix the positioned rivets;

[0035] Step 5: Complete the riveting sequentially. Press the riveting positioning mechanism pressure rod 31 again to push the combined brake pad assembly riveting fixture body along the slide groove 19 of the pad to the next positioning pin mounting hole, i.e., the second positioning pin mounting hole 182. Switch the riveting position, release the pressure rod, and let the positioning pin mounting hole slide to the position of the central shaft 32. The upper end of the central shaft is inserted into the second positioning pin mounting hole 182. The riveting machine pressure head 10 is aligned and positioned with the riveting pressure head insertion hole 15 in the center of the cover plate. Then use the riveting machine to rivet and fix the positioned rivets. Repeat the above riveting process, and then move sequentially to the third positioning pin mounting hole 183, the fourth positioning pin mounting hole 184, the fifth positioning pin mounting hole 185, the sixth positioning pin mounting hole 186, the seventh positioning pin mounting hole 187, the eighth positioning pin mounting hole 188, and the ninth positioning pin mounting hole 189. Complete the rivet installation one by one, and finally move out from the slide groove outlet 192 to complete the riveting assembly of the brake pad assembly.

[0036] This invention uses a limiting plate to maintain a gap between the steel backing and the friction body, formed by the elastic support of the disc spring. Therefore, the upward support of the limiting plate and the downward gravity of the cover plate ensure that the steel backing and the friction body maintain the same gap for riveting. This allows multiple friction bodies to have the same gap with the steel backing simultaneously, avoiding the uneven gaps caused by the operator manually adjusting the disc spring pressure one by one, which negatively impacts product quality. Using this groove, the brake pad assembly riveting fixture can be quickly and accurately moved on the bracket, allowing the riveting head insertion holes to be quickly aligned with the riveting head of the riveting machine for riveting and pressing. Therefore, the brake pad assembly riveting fixture can be used to arrange all friction bodies, disc springs, and rivets in their riveting positions before unified riveting, improving riveting efficiency. It ensures a uniform gap between the friction body and the steel backing, greatly improving the product quality of powder metallurgy brake pads for high-speed trains. The structure is simple, the manufacturing cost is low, and it is suitable for rapid manual operation.

[0037] In summary, the objective of this invention has been achieved.

Claims

1. A method for riveting and assembling powder metallurgy brake pads for high-speed trains, characterized in that: The assembly steps include: using a brake pad assembly riveting fixture body, bracket, and riveting positioning mechanism as riveting fixtures. The brake pad assembly riveting fixture body is a box-shaped clamping device consisting of a cover plate, a template on the side wall, and a pad at the bottom, which is fixed with bolts. The cover plate is provided with multiple riveting pressure head insertion holes corresponding to the friction body mounting holes of the steel back. A strip-shaped limiting plate is supported between the template and the cover plate to maintain a gap between the steel back and the friction body formed by the elastic support of the disc spring. Multiple positioning pins corresponding to the riveting pressure head insertion holes are inserted into the pad. The positioning pins are movably supported on the positioning pin mounting holes by the lower support platform and the end insertion pins. A groove is provided on the lower surface of the pad that connects to the positioning pin mounting holes. The groove is a continuous zigzag groove that gradually connects from the positioning pin mounting hole in the center of the pad to the outer positioning pin mounting holes. The zigzag groove has a groove inlet and a groove outlet at the edge of the pad. The bracket consists of an upper support plate with a central through hole and two equal-height support columns on both sides; The brake pad assembly riveting fixture body is matched with a riveting positioning mechanism. The riveting positioning mechanism includes a positioning plate set on the base of the riveting machine, a positioning sleeve set on the upper end of the positioning plate, a central shaft that slides through the positioning sleeve using a compression spring in the central cavity of the positioning plate, and a pressure rod connected to the outside of the central shaft. Step 1: Positioning of the brake pad assembly. First, insert all the corresponding positioning pins of the brake pad assembly into the positioning pin mounting holes on the pad. Then, place the corresponding rivets on the upper end of the positioning pins. Next, align the corresponding friction bodies and disc springs with the rivets and install them on the positioning pins in sequence. Place the steel backing above the rivets, align the friction body mounting holes of the steel backing with the nine rivets, and place it on the disc spring through the rivets. Leave a gap between the steel backing and all the friction bodies, formed by the elastic support of the disc spring. This completes the positioning of the brake pad assembly. Step 2: Assemble the brake pad assembly riveting fixture body, fasten the cover plate onto the steel back and limit plate, and connect and fix it to the template with screws; Step 3: Positioning the riveting positioning mechanism. Fix the riveting positioning mechanism on the base of the riveting machine and place it under the bracket. Align the riveting machine pressure head with the central shaft of the riveting positioning mechanism vertically. The upper end of the central shaft should protrude from the central through hole of the upper bracket. Then place the assembled brake pad assembly riveting fixture body on the bracket. Connect the sliding groove inlet on the bottom of the pad with the upper end of the central shaft. Press the pressure rod of the riveting positioning mechanism. The compression spring will contract under force, and the central shaft will move downward and retract into the sliding groove. Push the brake pad assembly riveting fixture body to slide along the sliding groove of the pad on the bracket. Release the pressure rod so that the positioning pin mounting hole in the center of the pad slides to the position of the central shaft. The central shaft will spring upward and the upper end of the central shaft will be inserted into the positioning pin mounting hole in the center of the pad. The riveting machine pressure head is now aligned with the riveting pressure head insertion hole in the center of the cover plate, completing the positioning. Step 4: Use a riveting machine to rivet and fix the positioned rivets; Step 5: Press the riveting positioning mechanism lever again to push the combined brake pad assembly riveting fixture body along the slide groove of the pad to the next positioning pin mounting hole. Switch the riveting position, release the lever, and let the positioning pin mounting hole slide to the center shaft position. The upper end of the center shaft is inserted into the positioning pin mounting hole of the pad. The riveting machine head is aligned with the riveting head insertion hole in the center of the cover plate. Then use the riveting machine to rivet and fix the positioned rivets. Repeat the above riveting process, and then install the remaining rivets one by one to finally complete the riveting assembly of the brake pad assembly.

Images