Powder metallurgy brake pad with floating effect for motor train unit and braking device

Abstract

This invention discloses a floating powder metallurgy brake pad and braking device for high-speed trains, relating to the field of powder metallurgy brake pad manufacturing technology. By setting a floating component between the steel backing and the friction block assembly, creating a floating gap between them, and designing the connecting component to have a clearance fit with both the steel backing and the friction block assembly, the hard contact between the friction block assembly and the steel backing in traditional powder metallurgy brake pads is transformed into an elastically adjustable flexible contact relationship. This structure allows the friction block assembly to generate moderate displacement in a direction perpendicular to the brake disc during braking, and to adapt to changes in the microstructure and thermal deformation of the brake disc surface within a certain range. This significantly improves the fit stability between the brake pad and the brake disc, reduces local stress concentration, mitigates the risk of friction block breakage and detachment caused by high-frequency braking impacts, and enhances the overall structural reliability and driving safety of the brake pad.

Description

Technical Field

[0001] This invention relates to the field of powder metallurgy brake pad manufacturing technology, and more specifically, to a powder metallurgy brake pad and braking device for high-speed trains with a floating effect. Background Technology

[0002] Centralized power EMUs are core equipment for upgrading passenger transport on existing railway lines. They are characterized by high operating speed, large axle load, high braking frequency, and concentrated braking load. The reliability of their braking system is directly related to railway traffic safety. As a key actuator of the braking system, the brake pads' core function is to convert the train's kinetic energy into frictional heat energy, thereby achieving smooth deceleration and reliable stopping. Their structural design and assembly quality are important foundations for ensuring the safe and efficient operation of trains.

[0003] Currently, in powder metallurgy brake pads of power-centralized EMUs, the connection between the friction block and the steel backing is mainly achieved through riveting. The friction block and the steel backing are in hard contact, which not only easily leads to local stress concentration during braking, causing the brake pad to break or detach under high-frequency braking impacts, posing a safety hazard, but also lacks an effective floating adjustment structure. During braking, the contact area between the brake pad and the brake disc is always unstable, which easily aggravates uneven wear of the brake pad, causes friction block detachment, and further reduces braking stability.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a powder metallurgy brake pad and braking device for high-speed trains with a floating effect.

[0006] This invention is implemented as follows: In a first aspect, the present invention provides a powder metallurgy brake pad for high-speed trains with a floating effect, comprising a steel back, a friction block assembly, a floating assembly, and a connecting assembly.

[0007] The steel back includes a first surface and a second surface arranged opposite to each other. The second surface is used to connect with the braking device of the EMU. The friction block assembly is fixed to the first surface by a connecting assembly. The connecting assembly is in clearance fit with the steel back and the connecting assembly is in clearance fit with the friction block assembly.

[0008] The floating component is located between the friction block assembly and the steel backing, and there is a floating gap between the friction block assembly and the steel backing, with a width of 0.5~1.5mm.

[0009] In an optional embodiment, the friction block assembly includes multiple friction blocks, each friction block being connected to the steel backing via a corresponding connecting component, and multiple floating components are also provided, each corresponding to one of the multiple friction blocks.

[0010] Each friction block includes a friction body, a back plate, and a friction block limiting pin.

[0011] A limit pin hole is provided on the back plate, and a friction block limit hole is provided on the steel back. The friction block limit pin passes through the limit pin hole and the friction block limit hole in sequence to connect the friction block with the steel back; the friction block and the back plate are welded together.

[0012] The friction block limiting pin has a clearance fit with the limiting pin hole and the friction block limiting hole.

[0013] In an optional embodiment, the gap between the friction block limiting pin and the limiting pin hole is 0.8~1.2mm; the gap between the friction block limiting pin and the friction block limiting hole is 0.8~1.2mm.

[0014] In an optional embodiment, both the friction body and the back plate are provided with interconnected chip removal holes; the diameter of the chip removal holes is 15~18mm; the chip removal holes are located at the center of the friction body.

[0015] In an optional embodiment, the connecting assembly connects the steel back and the friction block assembly through a chip removal hole, and the connecting assembly is clearance-fitted within the chip removal hole, with a clearance of 1~1.4mm.

[0016] In an optional embodiment, the friction block is trapezoidal in shape, and each corner of the trapezoid is rounded.

[0017] In an optional implementation, the trapezoid has an upper base length of 36-41 mm, a lower base length of 70-75 mm, and a height of 53-56 mm; the corner radius is 6-9 mm.

[0018] In an optional embodiment, the connecting component is a rivet, which includes a head and a shank, and a rivet limiting platform is provided at one end of the shank near the head, which protrudes annularly from the outer surface of the shank.

[0019] When multiple rivets are installed on the friction block and the steel back, the height difference of the multiple rivet limiting platforms is ≤0.05mm.

[0020] In an alternative implementation, the floating component includes a disc spring.

[0021] Secondly, the present invention provides a braking device, including the brake pads provided in any of the foregoing embodiments.

[0022] The present invention has the following beneficial effects: This invention provides a powder metallurgy brake pad and braking device for high-speed trains with a floating effect. By incorporating a floating component between the steel backing and the friction block assembly, creating a floating gap of 0.5-1.5 mm, and designing the connecting component to have a clearance fit with both the steel backing and the friction block assembly, the hard contact between the friction block assembly and the steel backing in traditional powder metallurgy brake pads is transformed into an elastically adjustable flexible contact relationship. This structure allows the friction block assembly to undergo moderate displacement in a direction perpendicular to the brake disc during braking, and to adapt to changes in the microstructure and thermal deformation of the brake disc surface within a certain range, significantly improving the contact stability between the brake pad and the brake disc. The increased contact area and dynamic self-adaptation of the contact state help improve the uniformity of friction force distribution during braking, reduce local stress concentration, and thus mitigate the risk of friction block breakage and detachment caused by high-frequency braking impacts, enhancing the overall structural reliability of the brake pad and driving safety. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A schematic diagram of the structure of a powder metallurgy brake pad for a high-speed train with a floating effect, provided in an embodiment of the present invention; Figure 2 A cross-sectional view of a powder metallurgy brake pad for a high-speed train with a floating effect, provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the friction block provided in an embodiment of the present invention; Figure 4 A schematic diagram of the steel backing structure provided in an embodiment of the present invention. Figure 1 ; Figure 5 A schematic diagram of the steel backing structure provided in an embodiment of the present invention. Figure 2 ; Figure 6 This is a schematic diagram of the rivet structure provided in an embodiment of the present invention.

[0025] Explanation of main component symbols: 100-Brake plate; 110-Steel back; 111-Friction block limiting hole; 112-Connecting hole; 113-Floating mounting groove; 114-Sinking groove; 120-Friction block; 121-Friction body; 122-Back plate; 1221-Limiting pin hole; 123-Friction block limiting pin; 124-Chip removal hole; 130-Disc spring; 140-Rivet; 141-Head; 142-Rod; 1421-Rivet limiting platform. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0027] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0028] Please see Figure 1 and Figure 2 This embodiment provides a powder metallurgy brake pad 100 for high-speed trains with a floating effect, including a steel back 110, a friction block assembly, a floating assembly, and a connecting assembly.

[0029] The steel back 110 includes a first surface and a second surface arranged opposite to each other. The second surface is provided with a dovetail-shaped assembly structure, specifically a dovetail groove in this embodiment, for connecting with the braking device of the EMU. The friction block assembly is fixed on the first surface by a connecting assembly. The connecting assembly is clearance-fitted with the steel back 110, and the connecting assembly is also clearance-fitted with the friction block assembly to ensure the floating effect of the friction block assembly.

[0030] The floating component is located between the friction block assembly and the steel back 110. There is a floating gap H between the friction block assembly and the steel back 110. The width of the floating gap H is 0.5~1.5mm, which ensures that the friction block assembly has good vertical floating adjustment capability and adapts to the surface shape of the brake disc.

[0031] In this embodiment, the friction block assembly includes multiple friction blocks 120, each friction block 120 is connected to the steel back 110 through a corresponding connecting component, and there are also multiple floating components, which are configured one-to-one with the multiple friction blocks 120.

[0032] Please see Figure 3 Each friction block 120 includes a friction body 121, a back plate 122, and a friction block limiting pin 123.

[0033] Please refer to the above. Figure 4 and Figure 5The back plate 122 has a limiting pin hole 1221, and the steel back 110 has a friction block limiting hole 111. The friction block limiting pin 123 passes through the limiting pin hole 1221 and the friction block limiting hole 111 in sequence, so that the back plate 122 is connected to the steel back 110. The friction block 120 and the back plate 122 are welded together, so that the friction block 120 is fixed as a whole on the steel back 110.

[0034] Furthermore, in order to facilitate the confirmation of the installation position of each friction block 120, the first surface of the steel back 110 is also provided with a friction block 120 mounting groove, and the friction block limiting hole 111 is located in the friction block 120 mounting groove to ensure that the friction block limiting hole 111 is correspondingly set with the limiting pin hole 1221, and to ensure that the friction block limiting pin 123 can pass through the friction block limiting hole 111 and the limiting pin hole 1221 at the same time.

[0035] In addition, the first surface of the steel back 110 is provided with a floating mounting groove 113 for accommodating the floating component; the floating mounting groove 113 is located in the mounting groove of the friction block 120.

[0036] To ensure the floating fit between the steel backing 110 and the friction block 120, the friction block limiting pin 123 and the limiting pin hole 1221 and the friction block limiting hole 111 are all clearance fits. Specifically, the clearance between the friction block limiting pin 123 and the limiting pin hole 1221 is 0.8~1.2mm; the clearance between the friction block limiting pin 123 and the friction block limiting hole 111 is 0.8~1.2mm.

[0037] By controlling the gap between the friction block limiting pin 123 and the limiting pin hole 1221 and the friction block limiting hole 111, the vertical floating effect of the friction body 121 can be maintained while achieving the deflection limiting of the friction body 121, thus avoiding excessive limiting that could lead to the failure of the floating structure.

[0038] In this embodiment, the floating component is a disc spring 130. The disc spring 130 has a certain deformation capacity and can provide a stable floating gap when the friction block assembly contacts the braking surface, thus ensuring the braking effect.

[0039] In this embodiment, the disc spring 130 has a large-diameter end and a small-diameter end. The large-diameter end contacts the friction block assembly, and the small-diameter end contacts the first surface of the steel back 110. This can effectively reduce the overturning moment of the friction block assembly, prevent local wear of a single friction block 120, and improve the overall service life of the brake pad 100.

[0040] Please see Figure 6 In this embodiment, the connecting component is a rivet 140, which includes a head 141 and a rod 142. The rod 142 is provided with a rivet limiting platform 1421 that protrudes from the outer surface of the rod 142 near the head 141.

[0041] When multiple rivets 140 are installed on the friction block 120 and the steel back 110, the height difference of the multiple rivet limiting platforms 1421 is ≤0.05mm.

[0042] Due to the lack of precision control in current riveting methods, the gap between the friction block 120 and the steel backing 110 is uneven, resulting in poor overall flatness of the brake pad 100 and insufficient initial contact area, which affects the braking response speed. This invention addresses this by setting a rivet limiting platform 1421 on the rivet 140 and using this as a basis to determine the height of multiple rivets 140, thereby controlling the gap H between all friction block assemblies on the steel backing 110 and the steel backing 110. This improves the overall flatness of the brake pad 100 after riveting, increases the initial contact area between the brake pad 100 and the brake disc, and ensures assembly accuracy.

[0043] Furthermore, since there are a large number of friction blocks 120 on each brake pad 100, and the existing brake pad 100 structure does not have a targeted heat dissipation and chip removal structure, the large amount of heat generated by braking cannot be dissipated quickly, which can easily cause permanent damage such as hot spots and cracks on the brake disc; at the same time, wear debris is easy to accumulate between the friction pairs, causing abnormal wear, resulting in reduced braking performance and unstable friction coefficient.

[0044] Therefore, in this embodiment, chip removal holes 124 that are interconnected are also provided on both the friction body 121 and the back plate 122; the diameter of the chip removal hole 124 is 15~18mm; the chip removal hole 124 is located at the center of the friction body 121.

[0045] By providing chip removal holes 124 on both the friction body 121 and the back plate 122, a natural heat dissipation channel and chip removal space can be formed, ensuring that the brake pad 100 has good heat dissipation and chip removal effects, reducing braking temperature and reducing wear debris accumulation.

[0046] In this embodiment, the connecting assembly connects the steel back 110 and the friction block assembly through the chip removal hole. The connecting assembly is clearance-fitted in the chip removal hole, and the clearance is 1~1.4mm to ensure that the friction block 120 has a good floating effect after riveting.

[0047] Furthermore, the steel back 110 is provided with a connecting hole 112 in the area corresponding to the chip removal hole 124. The connecting hole 112 passes through the first surface and the second surface of the steel back 110, and has a groove 114 structure on one side of the second surface of the steel back 110.

[0048] In this embodiment, the friction block 120 is trapezoidal in shape, and each corner of the trapezoid is rounded; specifically, the upper base of the trapezoid is 36~41mm long, the lower base is 70~75mm long, and the height is 53~56mm; the radius of the rounded corner is 6~9mm.

[0049] In this embodiment, in order to reduce the volume of the steel back 110, when two or more friction blocks 120 are arranged side by side on the steel back 110, the upper bottom and lower bottom of the trapezoidal structure of the two adjacent friction blocks 120 are arranged alternately.

[0050] By designing the friction block 120 as a trapezoidal structure with rounded corners, the rounded corners effectively improve the fit between the friction block 120 and the steel back 110, improve the friction area distribution of the brake pad 100, and effectively reduce stress concentration during braking.

[0051] Please see Figure 1 and Figure 2 This embodiment provides a powder metallurgy brake pad 100 for high-speed trains with a floating effect, and its assembly process is as follows: Step 1: Install the friction block limiting pin 123 into the limiting pin hole 1221 of the back plate 122 using a clearance fit to obtain a pre-assembled unit; weld the pre-assembled unit to the friction body 121 using a pressure sintering process to obtain the friction block 120. The sintering temperature is controlled at 850~900℃, and the holding time is 40~60min to ensure the welding strength between the friction body 121 and the back plate 122.

[0052] Step 2: Place the disc spring 130 into the floating mounting slot 113 of the steel back 110, ensuring that the disc spring 130 is fully embedded in the slot without any offset or jamming.

[0053] Step 3: Place the friction block 120 into the friction block 120 mounting groove of the steel backing 110, so that the friction block limiting pin 123 is precisely inserted into the friction block limiting hole 111 of the steel backing 110, thereby achieving the initial limiting of the friction block 120.

[0054] Step 4: Pass the rivet 140 through the chip removal hole 124 of the friction block 120, the center hole of the disc spring 130, and the connecting hole 112 of the steel back 110 in sequence, so that the shank 142 of the rivet 140 passes through the connecting hole 112 of the steel back 110 and is accommodated in the groove 114.

[0055] Step 5: Use press riveting or spin riveting to rivet the rod 142 of rivet 140, and ensure that rivet 140 fits tightly with the groove 114 of steel backing 110 after riveting; after riveting, check the floating gap H between friction block 120 and steel backing 110, and ensure that the gap value is 0.5~1.5mm, and finally obtain a powder metallurgy brake pad 100 for EMU with floating effect.

[0056] This embodiment provides a powder metallurgy brake pad 100 for high-speed trains with a floating effect, which has at least the following beneficial effects: 1. In this embodiment, the hard contact between the friction block 120 and the steel back 110 of the traditional riveted brake pad 100 and the steel back 110 is changed to elastic contact through the elastic support of the disc spring 130. Combined with the rounded corner design of the trapezoidal friction body 121, the local stress concentration during the braking process is greatly reduced, solving the industry pain point of brake pad 100 breakage and block falling off, and improving the driving safety factor.

[0057] 2. The chip removal hole 124 at the center of the friction body 121 and the alternating arrangement of the upper and lower bottoms of the trapezoidal structure form an efficient heat dissipation channel and chip removal space, which can quickly dissipate braking heat energy and prevent the brake disc from generating hot spots and cracks; at the same time, it can promptly remove wear debris, prevent abnormal wear of the friction pair, extend the service life of the brake pad 100 and the brake disc, and reduce operation and maintenance costs.

[0058] 3. The floating gap between the steel backing 110 and the friction block 120, combined with the gap design of the friction block limiting pin 123, enables the friction block 120 to have good vertical and deflection floating capabilities. During braking, the contact area between the brake pad 100 and the brake disc can reach more than 95%, the friction coefficient remains stable, effectively solves the problem of uneven wear, and improves the braking response speed and stability.

[0059] 4. The gap design of the friction block limiting pin 123 not only realizes the deflection limit of the friction body 121, but also avoids the impact on the floating effect, while reducing the shear force on the rivet 140 and reducing the risk of rivet 140 breaking and failing.

[0060] 5. By controlling the height of the rivet 140, the overall flatness of the brake pad 100 is ensured, the initial contact area between the brake pad 100 and the brake disc is increased, and the braking performance is further optimized. In addition, the rivet limiting platform 1421 on the rivet 140 is used for limiting, which prevents the disc spring 130 from being completely compressed after riveting, ensuring that the friction body 121 has a stable vertical and deflection floating effect, effectively reducing the problems of the friction block 120 falling off or detaching due to stress concentration, and structurally improving the braking performance and safety of the brake pad 100.

[0061] 6. The brake pad 100 provided in this embodiment has a simple overall structural design and easy riveting assembly process. It does not require special high-precision equipment and can achieve large-scale mass production, which meets the mass production needs of railway equipment.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A powder metallurgy brake pad for high-speed trains with a floating effect, characterized in that, Includes a steel backing, friction block assembly, floating assembly, and connecting assembly; The steel back includes a first surface and a second surface disposed opposite to each other, the second surface being used to connect with the braking device of the EMU; the friction block assembly is fixed on the first surface by a connecting assembly, the connecting assembly being clearance-fitted with the steel back and the connecting assembly being clearance-fitted with the friction block assembly; The floating component is located between the friction block assembly and the steel backing, and there is a floating gap between the friction block assembly and the steel backing, the width of which is 0.5~1.5mm.

2. The brake pad according to claim 1, characterized in that, The friction block assembly includes multiple friction blocks, each friction block is connected to the steel back through a corresponding connecting component, and there are also multiple floating components, each corresponding to one of the multiple friction blocks; Each friction block includes a friction body, a back plate, and a friction block limiting pin; The back plate has a limiting pin hole, and the steel back has a friction block limiting hole. The friction block limiting pin passes through the limiting pin hole and the friction block limiting hole in sequence to connect the friction block to the steel back; the friction block and the back plate are welded together. The friction block limiting pin is clearance-fitted with the limiting pin hole and the friction block limiting hole.

3. The brake pad according to claim 2, characterized in that, The gap between the friction block limiting pin and the limiting pin hole is 0.8~1.2mm; the gap between the friction block limiting pin and the friction block limiting hole is 0.8~1.2mm.

4. The brake pad according to claim 2, characterized in that, Both the friction body and the back plate are provided with interconnected chip removal holes; the diameter of the chip removal holes is 15~18mm; the chip removal holes are located at the center of the friction body.

5. The brake pad according to claim 4, characterized in that, The connecting assembly connects the steel back and the friction block assembly through the chip removal hole. The connecting assembly is clearance-fitted within the chip removal hole, and the clearance is 1~1.4mm.

6. The brake pad according to claim 2, characterized in that, The friction block is trapezoidal in shape, and each corner of the trapezoid is rounded.

7. The brake pad according to claim 6, characterized in that, The upper base of the trapezoid is 36-41mm long, the lower base is 70-75mm long, and the height is 53-56mm; the radius of the rounded corners is 6-9mm.

8. The brake pad according to claim 2, characterized in that, The connecting component is a rivet, which includes a head and a rod. The rod has an annular rivet limiting platform protruding from the outer surface of the rod near the head. When multiple rivets are installed on the friction block and the steel back, the height difference of the multiple rivet limiting platforms is ≤0.05mm.

9. The brake pad according to claim 1, characterized in that, The floating component includes a disc spring.

10. A braking device, characterized in that, Includes the brake pad as described in any one of claims 1 to 9.

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