A method for overhauling wheel-mounted brake discs

Abstract

This invention discloses a method for overhauling wheeled brake discs, including: turning the friction surface of the brake disc in pulley mode to eliminate concave wear, inclined wear, and wavy wear on the friction surface; disassembling the brake disc, retaining two disc bodies; cleaning, cold-pressing and straightening, and heat-treating the two disassembled disc bodies; separating the heat-treated disc bodies from special tooling, measuring the deformation of the disc bodies, and performing magnetic particle testing and ultrasonic testing, and selecting disc bodies that meet the reuse standards based on the testing results; installing the selected disc bodies according to the assembly requirements of a new brake disc, and replacing other components except the disc body; measuring the assembled brake disc, and finally selecting brake discs that meet the assembly requirements. This invention uses a combination of machining, cold-pressing and straightening, and heat treatment for overhauling, which can significantly improve the overhaul pass rate of old disc bodies and reduce the scrap rate of disc bodies.

Description

Technical Field

[0001] This invention relates to the field of rail vehicle braking technology, and in particular to a method for inspecting and maintaining wheel-mounted brake discs. Background Technology

[0002] The brake disc is a key component of disc brakes on rail vehicles. Based on their installation location, brake discs are classified into wheel-mounted brake discs and axle-mounted brake discs. Wheel-mounted brake discs are installed on the wheels, while axle-mounted brake discs are installed on the axles. During braking, the brake presses the brake pads against the brake disc. The braking friction torque generated by the friction between the brake pads and the brake disc achieves deceleration and stopping of the train.

[0003] Currently, high-speed trains, high-power locomotives, and some high-speed urban rail vehicles generally use disc brakes. Therefore, disc brakes are the most important braking method for rail vehicles, and brake discs are widely used.

[0004] Because wheels constantly rub against the rails, the shape of the wheel tread changes with use, affecting driving safety. Therefore, regulations require periodic turning and repair of the wheel tread. After several turning repairs, the wheel will reach its wear limit and be scrapped.

[0005] Because the diameter-to-thickness ratio of wheel-mounted brake discs can reach 15, making them typical thin-walled components, the brake disc heats up during braking due to friction with the brake pads; it then cools down during release. This repeated heating and cooling process generates thermal stress within the brake disc. Once the wheel-mounted brake disc is removed from a scrapped wheel and loses the constraint of its original fasteners, it will deform significantly and become unsuitable for reinstallation. Even if the wheel-mounted brake disc hasn't reached its wear limit, it will be scrapped along with the wheel, resulting in substantial waste.

[0006] Therefore, it is necessary to provide a maintenance method for wheeled brake discs and to reuse wheeled brake discs. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for overhauling wheel-mounted brake discs, thereby solving the problems mentioned in the background section.

[0008] To achieve the above objectives, the present invention provides a method for overhauling wheel-mounted brake discs, comprising the following steps:

[0009] S1 Turning: Turning the friction surface of the brake disc in the pulley condition to eliminate concave wear, inclined wear and wavy wear on the friction surface. The friction surface of the brake disc after turning must meet the technical requirements of a newly manufactured brake disc.

[0010] S2 Disassembly: Disassemble the brake discs, retaining two disc bodies, and scrap the old bolts, nuts, locating pins, O-rings and spacers that have been removed.

[0011] S3 Pretreatment: Clean the two disassembled discs, then cold press and shape the cleaned discs, then fix the cold-pressed and shaped discs on a special placement fixture, and put them together with the special fixing fixture into a heat treatment furnace for heat treatment.

[0012] S4 Deformation Screening: Separate the heat-treated disc from the special tooling, measure the deformation of the disc, and screen discs that meet the reuse standards based on the deformation.

[0013] S5 Flaw Detection Result Screening: Magnetic particle testing and ultrasonic testing are performed on the screened discs, and discs that meet the reuse standards are selected based on the flaw detection results.

[0014] S6 assembly disc body: Install the selected disc body according to the assembly requirements of the new brake disc, and replace other parts except the disc body;

[0015] S7 Final Inspection: The assembled brake discs are measured, and brake discs that meet the assembly requirements are finally selected.

[0016] As a further improvement to the above solution, the cleaning process in step S3 is as follows: the dirt, dust and rust on the heat dissipation fins, positioning pin mounting groove and mounting hole contact surface of the disassembled plate are cleaned and removed respectively.

[0017] The cold pressing and straightening process is as follows:

[0018] A. Place the cleaned disc horizontally on the special placement fixture with the friction surface facing down and in contact with the support surface of the placement fixture;

[0019] B. Use a press and special pressure fixture to apply back pressure to the disc body, so that the pressure fixture contacts the heat dissipation fins of the disc body, and ensure that the friction surface of the disc body is in complete contact with the support surface of the fixture.

[0020] C. Maintain pressure and use a 0.1mm thick feeler gauge to check the gap between the friction surface and the inner and outer diameter sides of the special tooling support surface. The insertion depth should not exceed 2mm; otherwise, continue to apply pressure.

[0021] D. Use a special fixing fixture to fix the tray onto a special placement fixture;

[0022] E. Finally, depressurize.

[0023] As a further improvement to the above scheme, the deformation measurement method in step S4 is specifically as follows:

[0024] After heat treatment, the disc body is separated from the special placement fixture and the special fixing fixture;

[0025] Place the disc horizontally on the measuring platform with the friction surface facing down and in contact with the supporting surface of the measuring platform.

[0026] The height H1 between the inner mounting surface of all the heat dissipation fins of the measuring plate and the support surface of the measuring platform is measured.

[0027] The height H2 between the outer mounting surface of all heat dissipation fins of the measuring plate and the support surface of the measuring platform is measured.

[0028] Calculate the warping and wave deformation of the disk body separately.

[0029] As a further improvement to the above scheme, the warping deformation amount = the maximum value among all the warping deformation values ​​of the heat dissipation fins; where: the warping deformation value of the heat dissipation fins = the absolute value of the height difference between the inner and outer sides of a single heat dissipation fin |H1-H2|.

[0030] As a further improvement to the above scheme, the wave deformation amount = (wave deformation amount on the outside of the heat dissipation fin + wave deformation amount on the inside of the heat dissipation fin) / 2; where: the wave deformation amount on the outside of the heat dissipation fin = the maximum value of the height of the outside of the heat dissipation fin - the minimum value of the height of the outside of the heat dissipation fin, and the wave deformation amount on the inside of the heat dissipation fin = the maximum value of the height of the inside of the heat dissipation fin - the minimum value of the height of the inside of the heat dissipation fin.

[0031] As a further improvement to the above scheme, in step S4, the disk body that meets the reuse standard in terms of deformation amount is a disk body with a warping deformation amount of no more than 0.2 mm and a wave deformation amount of no more than 0.2 mm.

[0032] As a further improvement to the above scheme, the disk that meets the reuse standard in step S5 is a disk whose flaw detection results meet the technical requirements of the new product.

[0033] As a further improvement to the above scheme, the assembly process in step S6 is as follows: the brake disc is fixed on the new wheel according to the assembly requirements of the new brake disc. The new parts to be replaced include bolts, nuts, locating pins, O-rings and spacers, wherein the disc body is the selected disc body.

[0034] As a further improvement to the above scheme, step S7 involves measuring the assembled brake disc, specifically including: measuring the runout of the friction surfaces on both sides of the assembled brake disc.

[0035] As a further improvement to the above solution, a brake disc with a runout measurement value of no more than 0.3 mm is considered a qualified product.

[0036] The beneficial effects of this invention are as follows:

[0037] 1. The inspection method of the present invention can reduce the deformation of old discs, and discs that meet the reuse standards can be selected through layer-by-layer screening, thus realizing the reuse of discs and reducing the later maintenance cost of brake discs.

[0038] 2. Compared with the existing fastener cold-drawing repair method, the present invention adopts a combination of machining, cold pressing and straightening and heat treatment for repair, which can significantly improve the repair qualification rate of old discs and reduce the scrap rate of discs. Moreover, the present invention is also applicable to some discs with too much deformation to be repaired by the fastener cold-drawing method. Therefore, the present invention has stronger adaptability and better effect.

[0039] 3. The repaired disc can meet the technical requirements of a new product. All other parts except the disc are replaced with new parts and then installed according to the assembly requirements of a new brake disc. Therefore, the repaired brake disc fully meets the vehicle's usage requirements. Attached Figure Description

[0040] Figure 1 This is a flowchart of a method for overhauling a wheeled brake disc provided in an embodiment of the present invention;

[0041] Figure 2 A schematic diagram of the structure of the brake disc in this invention;

[0042] Figure 3 This is a schematic diagram of cold-pressing straightening in this invention;

[0043] Figure 4 This is a schematic diagram of the measurement of disk deformation in this invention;

[0044] Figure 5 for Figure 2 Sectional view along the BB direction.

[0045] The components in the attached diagram are labeled as follows:

[0046] 1. Old wheel; 2. Brake disc; 21. Disc body; 211. Disc body friction surface; 212. Disc body heat dissipation rib surface; 213. Disc body positioning pin mounting groove; 214. Disc body mounting hole contact surface; 2121. Disc body heat dissipation rib inner mounting surface; 2122. Disc body heat dissipation rib outer mounting surface; 22. Bolt; 23. Nut; 24. Positioning pin; 25. O-ring; 26. Spacer; 3. Special placement fixture; 31. Placement fixture support surface; 4. Press; 5. Special pressure fixture; 51. Pressure fixture upper surface; 52. Pressure fixture lower surface; 6. Special fixing fixture; 7. Measuring platform; 71. Measuring platform support surface. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention. Example

[0048] The following is combined with Figures 1 to 4 This invention describes a specific embodiment of a method for overhauling wheeled brake discs.

[0049] A method for overhauling a wheel-mounted brake disc according to an embodiment of the present invention includes the following steps:

[0050] The disc friction surface 211 with the old wheel 1 is turned over to completely eliminate concave wear, inclined wear and wavy wear on the friction surface; the flatness of the disc friction surface 211 after turning over does not exceed 0.1mm and the runout value of the disc friction surface 211 is not greater than 0.3mm, ensuring that the friction surface of the brake disc after turning over meets the technical requirements of a newly manufactured brake disc.

[0051] Disassemble the brake disc according to the brake disc disassembly requirements, separate the brake disc 2 from the old wheel 1, retain the two disc bodies 21, and discard the old bolts 22, old nuts 23, old locating pins 24, old O-rings 25 and old spacers 26.

[0052] The dirt, dust, and rust on the disassembled disc heat dissipation fin surface 212, disc positioning pin mounting groove 213, and disc mounting hole contact surface 214 are cleaned and removed. By cleaning the disc 21, the deformation of the disc can be measured more accurately, the influence of dirt, dust, and rust on the flaw detection results can be reduced, and the influence of dirt, dust, and rust on the runout value of the assembled brake disc friction surface 211 can also be reduced.

[0053] Secondly, such as Figure 3As shown, the cleaned disc 21 undergoes cold pressing and shaping treatment, specifically including: placing the disc 21 horizontally on a special placement fixture 3 with the disc friction surface 211 facing downwards and in contact with the placement fixture support surface 31; using a press 4 and a special pressure fixture 5 to apply back pressure to the disc 21, with the press 4 in contact with the upper surface 51 of the pressure fixture and the lower surface 52 of the pressure fixture in contact with the disc heat dissipation fin surface 212, ensuring that the disc friction surface 211 is in complete contact with the placement fixture support surface 31; maintaining the output of the press 4... With the pressure stabilized, use a 0.1mm thick feeler gauge to check the gap values ​​on the inner and outer diameter sides of the disc friction surface 211 and the support surface 31 of the placement fixture, respectively. The insertion depth S1 on the inner diameter side and the insertion depth S2 on the outer diameter side should not exceed 2mm. If this is not met, increase the output pressure of the press 4 until the insertion depth S1 on the inner diameter side and the insertion depth S2 on the outer diameter side are not greater than 2mm. Use a special fixing fixture 6 to fix the disc 21 on the special placement fixture 3. Finally, depressurize. The disc 21 is not allowed to spring back after depressurization.

[0054] Then, the cold-pressed and shaped disc 21 is subjected to heat treatment, specifically including: placing the disc 21, which is fixed on the special placement fixture 3, together with the special fixing fixture 6, into the heat treatment furnace for heat treatment. Heat treatment can eliminate the internal thermal stress of the disc 21. The heat treatment temperature and heat treatment time must meet the requirements of the heat treatment process document to ensure that the internal thermal stress of the disc 21 is completely eliminated after heat treatment. At the same time, the mechanical properties and metallographic structure of the disc 21 must not be changed to ensure that the physical properties of the disc 21 meet the new manufacturing requirements.

[0055] Furthermore, loosen the special fixing fixture 6 and separate the heat-treated disc 21 from the special placement fixture 3.

[0056] like Figure 4 As shown, place the disk 21 horizontally on the measuring platform 7 with the friction surface 211 of the disk facing downwards, ensuring that the friction surface 211 of the disk is in contact with the support surface 71 of the measuring platform; use a height gauge to measure the height H1 between the inner mounting surface 2121 of all the heat dissipation fins of the disk and the support surface 71 of the measuring platform; use a height gauge to measure the height H2 between the outer mounting surface 2122 of all the heat dissipation fins of the disk and the support surface 71 of the measuring platform; calculate the warping deformation △1 of the disk 21; calculate the wave deformation △2 of the disk 21.

[0057] Among them, the warping deformation amount △1 = the maximum value among all the warping deformation values ​​of the heat dissipation fins; the warping deformation value of the heat dissipation fins = the absolute value of the height difference between the inner and outer sides of a single heat dissipation fin |H1-H2|.

[0058] Wherein, the wave deformation amount △2 = (wave deformation amount on the outside of the heat dissipation fin + wave deformation amount on the inside of the heat dissipation fin) / 2; the wave deformation amount on the outside of the heat dissipation fin = the maximum value of the height of the outside of the heat dissipation fin - the minimum value of the height of the outside of the heat dissipation fin, and the wave deformation amount on the inside of the heat dissipation fin = the maximum value of the height of the inside of the heat dissipation fin - the minimum value of the height of the inside of the heat dissipation fin.

[0059] Discs 21 with △1 not greater than 0.2mm and △2 not greater than 0.2mm are selected, and those discs 21 that do not meet the conditions are scrapped.

[0060] The selected discs 21 are subjected to magnetic particle testing and ultrasonic testing respectively. Discs 21 whose testing results meet the technical requirements of the new product are selected, and those discs 21 that do not meet the requirements are scrapped.

[0061] Prepare two selected disc bodies 21, new wheels, new bolts 22, new nuts 23, new locating pins 24, new O-rings 25, and new spacers 26, as well as other auxiliary materials, and install the brake disc according to the assembly requirements of the newly manufactured brake disc.

[0062] The runout of the friction surfaces 211 on both sides of the assembled brake disc is measured. Brake discs with a runout value of no more than 0.3 mm on both sides of the friction surfaces 211 are selected. Brake discs that do not meet the conditions are reassembled.

[0063] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0064] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0065] The above-described embodiments are merely examples and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for overhauling wheel-mounted brake discs, characterized in that: Includes the following steps: S1 turning: Turning the friction surface of the brake disc in pulley condition to eliminate concave wear, inclined wear and wavy wear on the friction surface; S2 Disassembly: Disassemble the brake discs, retaining two disc bodies, and scrap the old bolts, nuts, locating pins, O-rings and spacers that have been removed. S3 Pretreatment: Clean the two disassembled discs, then cold press and shape the cleaned discs, then fix the cold-pressed and shaped discs on a special placement fixture, and put them together with the special fixing fixture into a heat treatment furnace for heat treatment. S4 Deformation Screening: Separate the heat-treated disc from the special tooling, measure the deformation of the disc, and screen discs that meet the reuse standards based on the deformation. S5 Flaw Detection Result Screening: Magnetic particle testing and ultrasonic testing are performed on the screened discs, and discs that meet the reuse standards are selected based on the flaw detection results. S6 assembly disc body: Install the selected disc body according to the assembly requirements of the new brake disc, and replace other parts except the disc body; S7 Final Inspection: The assembled brake discs are measured, and brake discs that meet the assembly requirements are finally selected.

2. The method for overhauling a wheel-mounted brake disc according to claim 1, characterized in that: The cleaning process in step S3 specifically involves cleaning and removing dirt, dust, and rust from the disassembled heat dissipation fins, positioning pin mounting grooves, and mounting hole contact surfaces. The cold pressing and straightening process is as follows: A. Place the cleaned disc horizontally on the special placement fixture with the friction surface facing down and in contact with the support surface of the placement fixture; B. Use a press and special pressure fixture to apply back pressure to the disc body, so that the pressure fixture contacts the heat dissipation fins of the disc body, and ensure that the friction surface of the disc body is in complete contact with the support surface of the fixture. C. Maintain pressure and use a 0.1mm thick feeler gauge to check the gap between the friction surface and the inner and outer diameter sides of the special tooling support surface. The insertion depth should not exceed 2mm; otherwise, continue to apply pressure. D. Use a special fixing fixture to fix the tray onto a special placement fixture; E. Finally, depressurize.

3. The method for overhauling a wheel-mounted brake disc according to claim 1, characterized in that: The deformation measurement method in step S4 is as follows: After heat treatment, the disc body is separated from the special placement fixture and the special fixing fixture; Place the disc horizontally on the measuring platform with the friction surface facing down and in contact with the supporting surface of the measuring platform. The height H1 between the inner mounting surface of all the heat dissipation fins of the measuring plate and the support surface of the measuring platform is measured. The height H2 between the outer mounting surface of all heat dissipation fins of the measuring plate and the support surface of the measuring platform is measured. Calculate the warping and wave deformation of the disk body separately.

4. The method for overhauling a wheel-mounted brake disc according to claim 3, characterized in that: Warping deformation amount = the maximum value among all the warping deformation values ​​of the heat dissipation fins; where: the warping deformation value of the heat dissipation fins = the absolute value of the height difference between the inner and outer sides of a single heat dissipation fin |H1-H2|.

5. The method for overhauling a wheel-mounted brake disc according to claim 1, characterized in that: Wave deformation amount = (wave deformation amount on the outside of the heat dissipation fin + wave deformation amount on the inside of the heat dissipation fin) / 2; where: wave deformation amount on the outside of the heat dissipation fin = maximum value of the height of the outside of the heat dissipation fin - minimum value of the height of the outside of the heat dissipation fin, wave deformation amount on the inside of the heat dissipation fin = maximum value of the height of the inside of the heat dissipation fin - minimum value of the height of the inside of the heat dissipation fin.

6. The method for overhauling a wheel-mounted brake disc according to claim 1, characterized in that: In step S4, the disk that meets the reuse standard in terms of deformation is a disk with a warping deformation of no more than 0.2 mm and a wave deformation of no more than 0.2 mm.

7. The method for overhauling a wheel-mounted brake disc according to claim 1, characterized in that: In step S5, the disk that meets the reuse standard is the disk whose flaw detection results meet the technical requirements of the new product.

8. The method for overhauling a wheel-mounted brake disc according to claim 1, characterized in that: The assembly process in step S6 is as follows: the brake disc is fixed on the new wheel according to the assembly requirements of the new brake disc. The new parts to be replaced include bolts, nuts, locating pins, O-rings and spacers, and the disc body is the selected disc body.

9. The method for overhauling a wheel-mounted brake disc according to claim 1, characterized in that: Step S7 involves measuring the assembled brake disc, specifically including measuring the runout of the friction surfaces on both sides of the assembled brake disc.

10. A method for overhauling a wheel-mounted brake disc according to claim 9, characterized in that: Brake discs with a runout measurement value of no more than 0.3 mm are considered qualified products.

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