Supported slotted friction block of train brake pad

Abstract

A supported slotted friction block of train brake pad includes a friction block, comprising a slot that the friction block is configured with a support. The supported slotted friction block of train brake pad comprises a rear section, a top section, a bottom section, a slot and a support. The rear section is configured to the back portion of the friction block, providing braking force from a train brake pad. The slot creating by the elimination of a part of the friction block that slides on a train brake disc surface, dividing the friction block into the top section and the bottom section. The support is a structure configured with the friction block to act as a support structure.

Description

Supported slotted friction block of train brake pad

[0001] The present invention relates to the technical field of train brake pad. More particularly, it relates to a slotted friction block with support for use in train brake pad.

[0002] Trains are large vehicles and the importance of safety in the braking system of these high-speed vehicles seems to be vital. Therefore, the trailer axles of some trains may be equipped with several sets of independent disc brake units.

[0003] Currently, train brake pads may be categorized into two main types including integrated and split brake pads. The integrated brake pad can be created by joining a friction material with a brake pad while, the split brake pad can be formed by joining several friction materials with a brake pad, resulting in friction blocks. The brake pad configuration in a split train brake pad type might include multiple friction blocks of various shapes. These friction blocks could halt the train by transforming frictional force into thermal energy.

[0004] In the train brake system, the contact surfaces of the brake pad may undergo severe wear over time. This wear could lead to the accumulation of wear debris and may eventually result in the cracking and exfoliation of the friction material, which may negatively impact train safety. The main factor may be contributed to the instability of the braking system could be the friction-induced vibrations. These vibrations may diminish the effective contact interface, alter the applied torque, and may create stress concentrations in parts of the brake pad. Furthermore, the coupling phenomenon of vibrational modes can generate a brake squeal sound at train low speeds. Additionally, these unwanted vibrations could lead to more wear, which by creating small cracks at contact interface can pose a threat to the safety of the train. As wear and cracking intensify, fatigue and eventual failure may occur in the train brake pad. Moreover, uneven wear can result in the excessive use of friction materials and an uneven distribution of interface contact stress and this may also lead to a reduction in braking torque.

[0005] During braking, the wear debris, which separates from the frictional surfaces, may be placed between the friction block and the disc surface and may give rise to an accumulation of wear debris that might form a third body and may cause additional wear. This could increase the contact stress and may result in the creation of an impact force at the contact interface. Consequently, the impact force at the contact interface might trigger vibrations in braking system. These effects could contribute to a significant reduction in the effective contact interface and the formation of cracks in the friction block.

[0006] Therefore, in the friction blocks used in trains, a hole may be created to trap some of the wear debris and may aid in the better distribution of thermal stresses which forming perforated friction blocks. Although the hole in the friction blocks may trap some of the wear debris, a large portion of the friction block surface may still experience the accumulation of wear debris. This may lead to uneven wear, friction-induced vibrations, and noise. This friction-induced vibrations may result in deformation of the friction block and may cause the phenomenon of contact inclination angle and consequently might reduce the contact interface.

[0007] However, to increase the area for heat dissipation and aid in chip removal, a groove may be incorporated into some friction materials, which can also serve to trap wear debris.

[0008] US10731721B2 discloses an elastic adjustable brake pad for use in a train that relates to the technical field of trains that comprises a brake pad frame provided with a fourth through hole, a brake block assembly, and a spiral compression spring. The brake block assembly comprises a brake block, a rivet, a Belleville spring and a rivet sleeve. The brake block comprises a friction block and a static sheet steel back that fixedly mounted together. This brake pad has the advantages of automatically adjusting the brake clearance, ensuring the friction area at all times, improving brake efficiency and extending service life.

[0009] CN213744640U discloses a brake pad of a high-speed train that belongs to the technical field of brake machinery, comprises a brake pad back plate and more than three rows of friction plates arranged on the front side of the brake pad back plate. The friction plate includes a friction block, fixed on the surface of a T-shaped frame. The center of the friction block is provided with an axial hole and the center of the T-shaped frame is provided with an axial through hole. This configuration can facilitate ventilation and heat dissipation and also reduce weight and improve braking flexibility.

[0010] The hole created in the friction block is restricted to a certain part of the friction block. Therefore, a large part of the contact interface may not be capable of heat dissipation. Consequently, the perforated friction blocks may be incapable of achieving complete heat dissipation due to the small ventilation area. The accumulation of wear debris in some portions of the friction block, which can further cause more wear, might lead to an increase in the temperature at the contact interface. This may induce more thermal stresses and may increase friction-induced vibrations. Additionally, at both the US10731721B2 and CN213744640U patents, a slot with a support in the friction blocks has not been considered.

[0011] CN107152479B discloses a train brake pad that belongs to a train brake device which comprises a steel back, a bracket, a first friction block, and a second friction block. The first and second friction blocks are elastically connected to a bracket to form a friction unit. One side of the steel back is elastically connected with a plurality of friction units. A friction unit comprises arc-shaped projections, arc-shaped grooves, holes and pins, to be fixedly connected. Additionally, an elastic buffer structure is provided between the steel back and the bracket, and between the bracket and the first and second friction blocks. Such elastic buffers have been considered to mitigate the vibrations of the brake system. In addition, a transverse groove is provided in the middle of the friction blocks to increase the heat dissipation area.

[0012] However, the transverse groove, applied to the friction blocks has a simple structure and the friction blocks are considered with a transverse groove that has not considered any support for the friction blocks.

[0013] CN113236696B discloses a crimping type brake pad that pertains to the technical field of vehicle braking devices, comprising a quadrilateral with rounded corners carbon-ceramic composite friction block, a metal pressure plate, a metal tray and a steel back. Both sides of the friction block are provided with friction block ear plates. The friction block is clamped between the metal pressure plate and the metal tray and the three are locked by fastening components. The friction block and the metal tray are provided with mutually matched shearing protrusions and shearing grooves. The crimping connection between the friction block and the metal tray through the metal pressure plate has eliminated the riveting connection method. To dissipate heat and remove chips, in some embodiments of the invention, there is a chip removal groove, provided on the front surface of the friction block.

[0014] Nevertheless, the chip removal groove, provided in the friction block has a simple structure and the friction block does not have any support.

[0015] The third and fourth patents, CN107152479A1 and CN113236696A2, both utilize a simple groove without support in the friction block to aid in reducing heat dissipation and chip removal. However, none of the cited prior art mentions the creation of a support for a slotted friction block used in train brake pad. In practice, during braking, the separated parts of the friction block may have displacements due to the slot that may lead to vibrations and system instability. This may result in fatigue and failure of friction blocks. Additionally, the holes created in the train friction blocks might be unable to fully trap the wear debris.

[0016] The present invention may provide improvement in the vibrational behavior of the friction block in a train brake pad which might minimize possible instability and possible damage to the friction block and other train brake components.

[0017] An objective of the present invention is to provide a supported slotted friction block of train brake pad that might not have the deficiencies of the prior art. Aiming at such problems, the object of the invention is to provide a support for a friction block of train brake pad that comprises a slot.

[0018] In accordance with aspects of the present subject matter, a supported slotted friction block of train brake pad is provided that comprises a friction block and a slot, wherein the friction block is slotted, that the slotted friction block is configured with a support. The supported slotted friction block of train brake pad comprising a rear section, a top section, a bottom section, a slot and a support. The rear section configured to the back portion of the friction block, providing braking force from a train brake pad while braking operation. The slot creating by the elimination of a part of the friction block that slides on a train brake disc surface. Therefor the friction block is divided into the top section and the bottom section by the slot, whereby separate portions of the top section and the bottom section are formed. The support is a structure configured with the friction block to act as a support structure.

[0019] In an embodiment of the present invention, the support that is formed between the top section and the bottom section, configured on the inner lateral surfaces of the slot.

[0020] In another embodiment of the present invention, the support configured between the top section and the bottom section on the inner lateral surfaces of the slot, protrudes from the rear section.

[0021] In one embodiment of the present invention, the support configured to the friction block to connect the top section and the bottom section together, which are formed by the slot.

[0022] In another embodiment of the present invention, the friction block comprises at least one slot.

[0023] In yet another embodiment of the present invention, the friction block comprises at least one support.

[0024] perforated friction blocks, being used in trains may be incapable of fully trapping wear debris from the contact interface which might lead to the accumulation of such wear debris as a third body. This may result in friction-induced vibrations and instability in the brake system.

[0025] In addition, the intensity of brake system vibrations may have correlation with the friction force. The friction force during the wear process could undergo continuous changes. Consequently, the friction block constructed from elastic friction materials may experience substantial displacements. Thus, the friction-induced vibrations could lead to tangential displacements in the friction block, particularly at the leading edges of the portions separated by the slot in the friction block. These displacements may result in a contact inclination angle at the contact interface which may cause uneven wear in the friction block and an uneven distribution of pressure on the surface of the friction block. This ultimately might decrease the contact interface which could result in a high concentration of interface contact stress that may alter the contact angle. These phenomena may be contributed to noise pollutions which could impact the physical and mental health of train passengers. In addition, such problems may significantly reduce the lifespan of the train brake pad and could affect the operational efficiency of the train and potentially might lead to train accident.

[0026] For the purpose of surmounting the defects in the prior art, the present invention adopts the following technical solution for addressing the problems, by providing a supported slotted friction block of train brake pad.

[0027] The present invention provides a support in a friction block of train brake pad that comprises a slot. The supported slotted friction block of train brake pad comprises a rear section, a top section, a bottom section, a slot and a support. In which the slot divides the friction block into the top and bottom sections from the sliding surface of the friction block, which slides on a train brake disc surface. Therefore, not only the wear debris may be trapped in the slot from the contact interface which could be eliminated from the contact interface, but the support may also mitigate vibrations and displacements of the friction block that may be produced by the slot which is divided into sections. Hence utilizing the support as a support structure for the slotted friction block. Thereby the support of the slotted friction block may enhance the robustness of the slotted friction block which may provide stability and a larger contact interface.

[0028] The advantages of the present invention will be set forth in the following description.

[0029] In braking operation, wear debris can accumulate between the friction block and the train brake disc surface which may act as a third body. This not only could create contact stress but also could cause ploughing and exfoliations at the contact interface. By consideration of a slot with a support in the friction block of the present invention, wear debris could be trapped in the slot and may prevent the accumulation of wear debris in the contact interface. Advantageously, considering the slot with support in the friction block of the present invention may improve the wear and tribological behavior in the contact interface.

[0030] By consideration of a support for the friction block which comprises a slot according to the present invention, the robustness of the friction block may be enhanced and might help in mitigating the displacements and the vibrations in the friction block. Therefore, the contact interface may be expanded and might improve the performance of the braking system. Hence the contact inclination angle in the contact interface could be lessened and also may reduce the deformation of the friction block and consequently, could give rise to a more even distribution of the interface contact stress.

[0031] The squealing noise of the brake system at low train speed could stem from the coupling of the vibrational modes that by taking into consideration a support in a slotted friction block according to the present invention, may suppress the squeal noise and noise pollution.

[0032] An exemplary embodiment of the present invention is illustrated by way of example in the accompanying drawings in which like reference numbers indicate the same or similar elements and in which:Fig.1

[0033] is a perspective view of the structure of a supported slotted friction block of train brake pad according to the first embodiment of the present invention.Fig.2

[0034] is a rear view of the supported slotted friction block of train brake pad according to the first embodiment of the present invention.Fig.3

[0035] is a top-down view of the supported slotted friction block of train brake pad according to the first embodiment of the present invention.Fig.4

[0036] is a cross sectional view along a line A-A in.Fig.5

[0037] is a side-on view of the supported slotted friction block of train brake pad according to the first embodiment of the present invention.Fig.6

[0038] is a cross sectional view along a line B-B in.Fig.7

[0039] is a perspective view of the structure of a supported slotted friction block of train brake pad according to the second embodiment of the present invention.Fig.8

[0040] is a rear view of the supported slotted friction block of train brake pad according to the second embodiment of the present invention.Fig.9

[0041] is a top-down view of the supported slotted friction block of train brake pad according to the second embodiment of the present invention.Fig.10

[0042] is a cross sectional view along a line C-C in.Fig.11

[0043] is a side-on view of the supported slotted friction block of train brake pad according to the second embodiment of the present invention.Fig.12

[0044] is a cross sectional view along a line D-D in.Fig.13

[0045] is a perspective view of the structure of a supported slotted friction block of train brake pad according to the third embodiment of the present invention.Fig.14

[0046] is a rear view of the supported slotted friction block of train brake pad according to the third embodiment of the present invention.Fig.15

[0047] is a top-down view of the supported slotted friction block of train brake pad according to the third embodiment of the present invention.Fig.16

[0048] is a cross sectional view along a line E-E in.Fig.17

[0049] is a side-on view of the supported slotted friction block of train brake pad according to the third embodiment of the present invention.Fig.18

[0050] is a cross sectional view along a line F-F in.Fig.19

[0051] is a perspective view of a schematic structure of an exemplary small-scale test brake dynamometer utilized for the test of the first and the second embodiments of the present invention in finite element analysis.Fig.20

[0052] is a graph that illustrates a comparison of the average displacements of four nodes in the direction of the interfacial friction force, with results obtained from using the first embodiment of the invention in finite element analysis.Fig.21

[0053] is a graph that illustrates a comparison of the average displacements of four nodes in the direction of the interfacial friction force, with results obtained from using the second embodiment of the invention in finite element analysis.Fig.22

[0054] is a diagram that illustrates a comparison of the interface contact area over time and the maximum interface contact stress distribution, with results obtained from using the first embodiment of the invention in finite element analysis.Fig.23

[0055] is a diagram that illustrates a comparison of the interface contact area over time and the maximum interface contact stress distribution, with results obtained from using the second embodiment of the invention in finite element analysis.

[0056] In order to elucidate the objectives, technical solutions, and benefits of the present invention embodiments, the technical solutions will be comprehensively detailed, with reference to the drawings of the present invention embodiments.

[0057] Detailed reference will be made to the embodiments of the invention and examples of which are illustrated explanation of the invention, not limitation of the invention. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention, in the sense that features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Hence, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. In addition, the detailed description of the embodiments, provided with the accompanying drawings, does not intend to limit the scope of protection of the present invention claims and merely represents selected embodiments of the present invention.

[0058] As mentioned, the present disclosure relates to the utilization of a support in a friction block of a train brake pad that comprises a slot. Referring to the drawings,illustrates a perspective view of the first embodiment of a supported slotted friction block of train brake pad 10 and in this embodiment is considered as a pentagonal shape friction block 1. As shown, the supported slotted friction block of train brake pad 10 comprises a friction block 1, a slot 14 and a support 15. Due to the slot 14 formed within the friction block 1, the friction block 1 may be segmented into various sections. Accordingly, the supported slotted friction block of train brake pad 10 includes a rear section 11, a top section 12, a bottom section 13, a slot 14 and a support 15.

[0059] Referring to, the rear section 11 configured to the back portion of the friction block 1 which may provide braking force from a train brake pad during braking operation. For example, when a train brake pad pressed during braking operation, the rear section 11 could convey the braking force to a train brake disc.

[0060] Referring toand, the slot 14 could be created by the elimination of a part of the friction block 1 from a sliding surface of the friction block 1 that slides on a train brake disc surface. Therefore, the friction block 1 may be divided into the top section 12 and the bottom section 13 by the slot 14, thereby forming separate sections of the top section 12 and bottom section 13. As an optional embodiment of the invention, the friction block 1 may comprise several slots 14.

[0061] Referring toand, the support 15 is a structure configured with the friction block 1 to act as a support structure that may mitigate displacements and vibrations of the friction block 1 that comprise a slot 14. For example, during braking operation, interfacial friction force may be created in the contact interface between the sliding surface of the friction block 1 and a train brake disc. Such interfacial friction force may give rise to displacements and vibrations in the friction block 1 which support 15 may mitigate the displacements and vibrations of the friction block 1. As a preferred embodiment of the invention, the support 15 may be disposed between the top section 12 and the bottom section 13 and may be configured on the inner lateral surfaces of the slot 14 and could protrude from the rear section 11. As mentioned as an optional embodiment of the invention, the friction block 1 may comprise several slots 14. Ergo as an optional embodiment of the invention, the friction block 1 may comprise several supports 15.

[0062] As depicted inand, one example of support 15 in this embodiment is considered in triangular shape. Nevertheless, the structure of the support 15 is not limited to a particular structure and the support 15 in one embodiment may include structures such as polygonal, circular, elliptical, pyramidal, prismatic, rod, truss and the like. Other structure of support 15 may be used, consistent with the spirit of the invention.

[0063] Referring toto, the technical features of the second embodiment of the present invention are essentially the same as those of the first embodiment, but the difference lies in:

[0064] Referring toto, in the second embodiment of the invention the shape of a supported slotted friction block of train brake pad 1 is considered as a hexagonal shape friction block 1.

[0065] Referring toto, the technical features of the third embodiment of the present invention are essentially the same as those of the first embodiment, but the difference lies in:

[0066] Referring toto, as a preferred embodiment of the invention, in the third embodiment of the invention the support 15 may be configured to the friction block 1 which comprises the slot 14, to connect the top section 12 and the bottom section 13 together, which are formed by the slot 14 to provide support for the friction block 1. In this embodiment, the support 15 may be disposed outside of the slot 14 to connect the top section 12 and the bottom section 13 together. As depicted into, one example of support 15 in this embodiment is considered to be a L-shaped structure. Nonetheless, in this embodiment, the structure of the support 15 is not limited to a particular structure. Other structure of support 15 may be used, consistent with the spirit of the invention. As an optional embodiment of the invention, the friction block 1 may comprise several slots 14 and may include several supports 15 regardless of the structure and the position of the support 15.Examples

[0067] In this example, finite element analysis has been used to analyze two embodiments of the supported slotted friction block of train brake pad 10. Referring to, the present invention takes a small-scale test brake dynamometer as an example and utilizes the first and the second embodiments of the present invention for test in finite element analysis in the small-scale test brake dynamometer. Taking into account calculation accuracy, as depicted in, in this example a simplified small-scale test brake dynamometer is utilized including the key components of the brake dynamometer including the supported slotted friction block of train brake pad 10, brake disc 2, friction block fixture 3, linear bearing 4 and brake push rod 5.

[0068] For this matter in this example, two embodiments of supported slotted friction block of train brake pad 10 are considered as a test group which includes the first and the second embodiments of the present invention. Furthermore, two perforated friction blocks, used in the prior art and similar to the friction blocks of the present invention, with an area equal to that of the two embodiment friction blocks in the present invention, are considered as the control group.

[0069] Hence this example could be considered to compare the results of the contact behavior in the contact interface of the first and the second embodiments of the present invention with the similar perforated friction blocks used in the prior art.

[0070] In this example, the interaction between the brake disc 2 and the two embodiments friction blocks 1 of the invention, as well as the push rod 5 and the linear bearing 4 is frictional contact, and the friction coefficient is considered to be 0.5 and 0.1 respectively. To ensure the equivalent linear velocity at the mean friction radius between the simulated and actual conditions, the angular velocity of 400 rpm and 10000 rpm were considered for the brake disk 2 which may simulate the train speed of approximately 12 km / h and 300 km / h respectively and the duration of analysis is considered to be 0.3 seconds.

[0071] During the braking operation, the interfacial friction force may cause displacements and vibrations in the friction blocks. This may contribute to the deformation of the friction blocks and may result in a possible change in the contact inclination angle at the contact interface. In this example, four nodes along the pressing direction of the friction blocks have been considered. These nodes are used to measure the displacements in the direction of the interfacial friction force which is tangential to the contact interface. By measuring the average displacements, the contact inclination angle may be determined. Furthermore, the contact inclination angle may lead to imperfect contact in the contact interface. Thus, a larger contact inclination angle might reduce the interface contact area and may also increase the interface contact stress.

[0072] Referring toand, the average displacements of four nodes at angular velocities of 400 rpm and 10000 rpm are depicted for two types of perforated friction blocks used in the prior art and the two embodiments of the present invention friction block 1. At both angular velocities, the average deformation value that could demonstrate the contact inclination angle, in perforated friction blocks is higher than both the first and the second embodiments of the invention. Therefore, the contact inclination angle in the first and the second embodiments of the invention, may be lower than that in the perforated friction blocks used in the prior art.

[0073] Referring toand, the interface contact area and the maximum of interface contact stress at angular velocities of 400 rpm and 10000 rpm are depicted for two types of perforated friction blocks used in the prior art and two embodiments of the present invention friction block 1. At both angular velocities, the average interface contact area in the first and the second embodiments of the present invention is higher than that of perforated friction blocks. Such that, the average interface contact area at an angular velocity of 10000 rpm in the pentagonal perforated friction block is approximately 90 square millimeters. In contrast, in the supported slotted friction block of train brake pad 10, it is approximately 254 square millimeters. Also, at an angular velocity of 10000 rpm in the hexagonal friction blocks, the perforated one is approximately 79 square millimeters, while in the supported slotted friction block of train brake pad 10, it is approximately 184 square millimeters. Additionally, at both angular velocities, the maximum of the interface contact stress in the two embodiments of the present invention is lower than that of perforated friction blocks used in the prior art.

[0074] This written description uses examples to disclose the invention and also to enable any person skilled in the art to practice the invention, including making and using any devices and systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

[0075] According to the present invention, the supported slotted friction block of train brake pad is provided that could be utilized in the train brake pad. By consideration of the support for the friction block of train brake pad which comprises a slot according to the present invention, the robustness of the friction block may be enhanced and might help in mitigating the displacements in the friction block of the train brake pad. This may contribute to enhancing the stability of the train braking system.

[0076] 1. Friction block

[0077] 10. Supported slotted friction block of train brake pad

[0078] 11. Rear section

[0079] 12. Top section

[0080] 13. Bottom section

[0081] 14. Slot

[0082] 15. Support

[0083] 2. Brake disc

[0084] 3. Friction block fixture

[0085] 4. Linear bearing

[0086] 5. Brake push rodPatent Literature

[0087] Patent US10731721B2

[0088] Patent CN213744640U

[0089] Patent CN107152479B

[0090] Patent CN113236696B

Claims

A supported slotted friction block of train brake pad (10), comprising: a friction block (1); and a slot (14); characterized by further comprising a support (15), wherein; the supported slotted friction block of train brake pad (10) comprising a rear section (11); a top section (12); a bottom section (13); a slot (14); and a support (15); the rear section (11) configured to the back portion of the friction block (1), providing braking force from a train brake pad; the slot (14) created by eliminating a part of the friction block (1) that slides on a train brake disc surface such that the friction block (1) dividing into the top section (12) and the bottom section (13) by the slot (14), whereby separate portions the top section (12) and the bottom section (13) are formed such that the friction block (1) is slotted; the support (15) is a structure configured with the friction block (1) to act as a support structure.The supported slotted friction block of train brake pad (10) as in Claim 1, wherein the support (15) configured between the top section (12) and the bottom section (13) so that the support (15) configured on the inner lateral surfaces of the slot (14).The supported slotted friction block of train brake pad (10) as in Claim 2, wherein the support (15) configured between the top section (12) and the bottom section (13) protrudes from the rear section (11).The supported slotted friction block of train brake pad (10) as in Claim 1, wherein the support (15) configured to connect the top section (12) and the bottom section (13) together.The supported slotted friction block of train brake pad (10) according to any one of Claims 1–4, wherein the friction block (1) comprises at least one slot (14).The supported slotted friction block of train brake pad (10) according to any one of Claims 1–5, wherein the friction block (1) comprises at least one support (15).

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