Brake pad with surface coating

Abstract

brake pad (100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100) comprising: a support plate (101) with a mounting surface (103), a friction lining (105) attached to the mounting surface (103) and having a tribological surface (107) which runs parallel to the mounting surface (103) within a specified tolerance; and a surface coating (109) which is attached to a part of the tribological surface (107) using an adhesive and which, when viewed in a direction perpendicular to the tribological surface (107), has a predetermined circumferential shape, wherein the tribological surface (107) of the friction lining (105) is configured to transmit frictional forces to a brake disc, wherein the surface coating (109) is a composite material, the composite material containing potassium titanate and further configured to create a transfer layer on the brake disc

Description

AREA OF TECHNOLOGY

[0001] This revelation concerns brake pads. BACKGROUND

[0002] Brake pads used in motor vehicles undergo a "bedding-in process" in which friction material gradually deposits on the surface of the brake disc. After this bedding-in process, the brake pads perform more efficiently and transmit braking force more smoothly.

[0003] The embedding process, however, is time-consuming and, to be as effective as possible, may require slow and controlled operation for newly installed brakes. With current brake systems, rapid heat build-up can occur if the brakes are applied before or during the embedding process, which can lead to damage to the brake disc due to warping. The brake pads themselves can experience surface glazing if exposed to excessive heat, reducing brake efficiency and shortening the service life of the brake pads.

[0004] US 2019 / 0 277 359 A1, DE 699 15 483 T2 and US 2021 / 0 062 880 A1 disclose brake pads which, in addition to a friction material covering the carrier surface of the respective brake pad, also have a further material deposited on a tribological surface of the friction material. This further material may comprise a composite material consisting solely of non-metallic materials. SUMMARY

[0005] The present invention provides a brake pad with the features of claim 1.

[0006] The foregoing aspects of this revelation and further aspects will be explained in more detail below with reference to the accompanying drawings. List of characters The Fig. Figure 1 shows a brake pad with a surface coating. The Fig. Figure 2 is a representation of a brake pad with a surface coating applied according to a predefined design. Fig. Figure 3 is a representation of a brake pad with a surface coating applied with a predefined design. The Fig. Figure 4 is a representation of a brake pad with a surface coating applied with a predefined design. The Fig. Figure 5 is a representation of a brake pad with a surface coating applied with a predefined design. The Fig. Figure 6 is a representation of a brake pad with a surface coating applied with a predefined design. The Fig. Figure 7 is a representation of a brake pad with a surface coating applied with a predefined design. The Fig. Figure 8 is a representation of a brake pad with a surface coating applied with a predefined design. The Fig. Figure 9 is a representation of a brake pad with a surface coating applied with a predefined design. The Fig. Figure 10 is a representation of a brake pad with a surface coating applied with a predefined design. The Fig. Figure 11 is a representation of a brake pad with a surface coating applied with a predefined design. DETAILED DESCRIPTION

[0007] The illustrated embodiments are disclosed with reference to the drawings. It is understood, however, that the disclosed embodiments are merely examples, which can be implemented in various and alternative forms. The figures are not necessarily to scale, and some features may be exaggerated or minimized to show details of certain components. The disclosed specific design and functional details are not to be interpreted as limiting, but rather as a representative basis for conveying to a person skilled in the art the practical implementation of the disclosed concepts.

[0008] The Fig. Figure 1 shows a brake pad 100 according to an embodiment of the teachings disclosed herein. The brake pad 100 comprises a carrier plate 101 with a mounting surface 103. The mounting surface 103 can be configured to provide a coupling surface between the carrier plate 101 and a friction lining 105. The friction lining 105 can be configured to apply frictional forces to a brake disc, thereby generating braking force for a vehicle. Frictional forces of the friction lining 105 are transmitted via a tribological surface 107, which runs substantially parallel to the mounting surface 103 within a predetermined tolerance. The formulation of the friction lining 105 can be suitable for a specific vehicle type, a specific brake design, a specific brake disc type, or any combination thereof, without deviating from the teachings disclosed herein.

[0009] During normal braking operations, the friction lining 105 wears down and can leave residual material on the surface of a drum rotor during an embedding period. This residual material is referred to as the "transfer layer," and a suitably designed transfer layer can improve braking efficiency, ease of brake force application, and brake lining service life. Until the embedding process is complete, the brakes may operate at suboptimal performance.

[0010] The transfer layer also reduces heat build-up during braking, potentially preventing damage to the brake disc or adverse effects of heat on the friction lining. However, since the friction lining 105 is formulated to counteract wear, the embedding process may take longer than desired. For this reason, the brake pad 100 includes a surface coating 109 applied to the tribological surface 107 of the friction lining 105.

[0011] The surface coating 109 can advantageously be formulated to readily generate a transfer layer that exhibits similar properties to the friction lining 105, but forms more rapidly during normal operation. Within certain tolerances, the transfer layer generated by the surface coating 109 can exhibit similar frictional properties to a transfer layer generated by the friction lining 105, except that the transfer layer can be generated at significantly lower temperature levels and with significantly fewer braking cycles than the friction lining 105 alone. This protects the brake disc from heat-induced distortion and the friction lining 105 from adverse conditions caused by heat buildup during embedding.In some earlier designs, embedding could require 300 to 400 operating miles; however, the addition of the surface coating 109 can advantageously reduce the operating effort required for complete embedding. The formulation of the surface coating 109 may be suitable for a particular vehicle type, brake design, brake disc type, friction lining formulation, or any combination thereof, without departing from the teachings disclosed herein.

[0012] The braking performance can be improved during the embedding process based on the formulation of the friction lining 105 and the surface coating 109. In some embodiments, the friction lining 105 can comprise a first composite material, and the surface coating 109 can comprise a second composite material having some of the same components as the friction lining 105. In some embodiments, a formulation of the surface coating 109 having some components like those of the friction lining 105 can improve the braking function or the effective service life of the brake lining.

[0013] A variety of materials can be used in formulations of the surface coating 109. In some embodiments, the surface coating 109 can comprise a composite of non-metallic materials. In some embodiments, the surface coating 109 can comprise composites of materials such as titanates, lubricants, abrasives, fillers, fibers, binders, or pH modifiers. By way of example, and without limitation, titanates in the composite can include potassium titanate, sodium titanate, and potassium magnesium. By way of example, and without limitation, lubricants in the composite can include antimony trisulfide, tin sulfide, or zinc sulfide. By way of example, and without limitation, abrasives in the composite can include zirconium, zirconium oxide, aluminum oxide, magnetite, or mullite.For example, and without limitation, fillers in the composite material may include barite, mica, ceramic granules, or mineral granules. For example, and without limitation, fibers in the composite material may include ceramic fibers, mineral fibers, or basalt fibers. For example, and without limitation, binders in the composite material may include inorganic resin, organic resin, sodium silicate, or a polyblend of unpolished casting material. For example, and without limitation, pH modifiers in the composite material may include lime or potassium salt. Other materials of one or more categories may be used without deviating from the teachings disclosed herein.

[0014] In some embodiments, different forms of materials can be used, such as two or more distinguishable potassium titanates, without deviating from the teachings disclosed herein. The compositions of the surface coating 109 can vary slightly in their respective inclusion components without deviating from the teachings disclosed herein. For example, a composition may comprise 70 to 80 wt.% resin, 10 to 20 wt.% zirconium dioxide, 2.5 to 12.5 wt.% potassium titanate, and 0 to 5 wt.% antimony trisulfide. In another exemplary embodiment, a composition may comprise 47 to 57% sodium silicate, 16 to 26% zirconium dioxide, 16 to 26% barite, 0 to 5% antimony trisulfide, and 0 to 5% magnetite.In yet another exemplary embodiment, a composition may comprise 20 to 30% polyblend of unground casting material, 15 to 25% zirconium dioxide, 15 to 20% barite, 0 to 5% antimony trisulfide, 0 to 5% magnetite and up to 30% water.

[0015] Some embodiments may include composites with up to 40% zirconium dioxide, up to 20% zirconium, up to 10% potassium titanate, up to 20% barite, up to 5% ceramic fibers, up to 5% Sb₂S₃, up to 5% SNS₂, up to 5% mica, or a combination of the above components in the listed amounts, without deviating from the teachings disclosed herein. In some embodiments, resin may be used to balance the composition if the other components do not result in a 100% mixture, without deviating from the teachings disclosed herein. Further embodiments may include additional compositions without deviating from the teachings disclosed herein.

[0016] The surface coating 109 can be applied to the friction lining 105 using an adhesive. The adhesive can be formulated for a predetermined curing time that is long for a complete application, but short enough that adding a surface coating to the brake lining 100 has a minimal impact on manufacturing and production times. In some embodiments, the curing times can be 180 seconds or less. In some embodiments, the curing times can be 60 seconds or less. In some embodiments, commercially available adhesives, such as a fast-drying formulation, can be used. In some embodiments, the adhesive can comprise aliphatic resin or polyvinyl acetate. Further embodiments can include other formulations without departing from the teachings disclosed herein.

[0017] In the Fig. Figure 1 shows a brake pad 100 having a uniform application of the surface coating 109 over the entire area of ​​the tribological surface 107 of the friction lining 105. Further embodiments can include different coatings, which can be advantageously used to accommodate different vehicle specifications. The surface coating 109 can be applied by means of an embossing process, which is suitable for a wide variety of coating designs. An embossing process can advantageously allow the use of any design desired during manufacturing.

[0018] In the illustrated embodiment, the surface coating 109 gives the friction lining 105 a clearly recognizable visual appearance and makes the design of the coating visually identifiable. Such visual distinguishability can advantageously allow the surface coating 109 to be applied to the friction lining 105 in such a way that, in addition to operational advantages, branding is possible. Any design can be used when applying the surface coating 109 without deviating from the teachings disclosed herein. For example, a design with a specific aesthetic or trademarked design can be sold to identify a brake lining as being manufactured by a particular manufacturer.

[0019] The Fig. Figure 1 shows an embodiment in which the surface coating 109 completely covers the tribological surface 107 of the friction lining 105. Further embodiments may include additional configurations of the surface coating 109. By way of example, and without limitation, some embodiments may concentrate the surface coating 109 in parts of the tribological surface 107 that are intended to experience more frequent contact with a brake disc during operation. In some embodiments, parts of the tribological surface 107 that are intended to experience more frictional forces during operation may have a concentration of the surface coating 109. Further embodiments may include additional configurations without departing from the teachings disclosed herein.

[0020] The Fig. Figure 2 is a representation of a brake pad 200 that uses the same carrier plate 101, the same friction lining 105, and the same formulation of the surface coating 109 as the brake pad 100, except that the application of the surface coating 109 forms a pair of spaced-apart circles. Further embodiments may include a different number of circles without deviating from the teachings disclosed herein. Further embodiments may include a number of circles with different dimensions or positions relative to the friction lining 105 without deviating from the teachings disclosed herein. Further embodiments may include a number of elliptical shapes other than circles without deviating from the teachings disclosed herein.

[0021] The Fig. Figure 3 is a representation of a brake pad 300 that uses the same carrier plate 101, the same friction lining 105, and the same formulation of the surface coating 109 as the brake pad 100, except that the application of the surface coating 109 forms a pair of spaced-apart rings. Further embodiments may include a different number of rings without deviating from the teachings disclosed herein. Further embodiments may include a number of rings with different dimensions or positions relative to the friction lining 105 without deviating from the teachings disclosed herein.

[0022] The Fig. Figure 4 is a representation of a brake pad 400 that uses the same carrier plate 101, the same friction lining 105, and the same formulation of the surface coating 109 as the brake pad 100, except that the application of the surface coating 109 forms a pair of spaced-apart strips. Further embodiments may include a different number of strips without deviating from the teachings disclosed herein. Further embodiments may include a number of strips with different dimensions or positions relative to the friction lining 105 without deviating from the teachings disclosed herein.

[0023] The Fig. Figure 5 is a representation of a brake pad 500 that uses the same carrier plate 101, the same friction lining 105, and the same formulation of the surface coating 109 as the brake pad 100, except that the application of the surface coating 109 forms a group of three spaced-apart strips. Further embodiments may include a different number of strips without deviating from the teachings disclosed herein. Further embodiments may include a number of strips with different dimensions or positions relative to the friction lining 105 without deviating from the teachings disclosed herein.

[0024] The Fig. Figure 6 is a representation of a brake pad 600 that uses the same carrier plate 101, the same friction lining 105, and the same formulation of the surface coating 109 as the brake pad 100, except that the application of the surface coating 109 forms a pair of angled strips. Further embodiments may include a different number of strips without deviating from the teachings disclosed herein. Further embodiments may include a number of strips with different dimensions or positions relative to the friction lining 105 without deviating from the teachings disclosed herein.

[0025] The Fig. Figure 7 is a representation of a brake pad 700 that uses the same carrier plate 101, the same friction lining 105, and the same formulation of the surface coating 109 as the brake pad 100, except that the application of the surface coating 109 forms a pair of angled strips. Further embodiments may include a different number of strips without deviating from the teachings disclosed herein. Further embodiments may include a number of strips with different dimensions or positions relative to the friction lining 105 without deviating from the teachings disclosed herein.

[0026] The Fig. Figure 8 is a representation of a brake pad 800 that uses the same carrier plate 101, the same friction lining 105, and the same formulation of the surface coating 109 as the brake pad 100, except that the application of the surface coating 109 forms a strip. Further embodiments may include a different number of strips without deviating from the teachings disclosed herein. Further embodiments may include a number of strips with different dimensions or positions relative to the friction lining 105 without deviating from the teachings disclosed herein.

[0027] The Fig. Figure 9 is a representation of a brake pad 900 that uses the same carrier plate 101, the same friction lining 105, and the same formulation of the surface coating 109 as the brake pad 100, except that the application of the surface coating 109 is asymmetrical to the tribological surface of the friction lining 105. In particular, the surface coating 109 varies with respect to a position along a length x of the friction lining 105. The variation of the application in the illustrated embodiment changes along the length x with respect to a width y of the friction lining 105. At a proximal end x1 of the length x, the entire associated width y is covered by the surface coating 109. At a distal end x2 of the length x, the friction lining 105 is not covered by the surface coating 109 at any point along the width y.The coverage of the surface coating 109 with respect to width y gradually decreases between the proximal end x1 and the distal end x2. In the illustrated embodiment, the coverage of the surface coating 109 tapers linearly; however, other embodiments may include different arrangements without deviating from the teachings disclosed herein. In some embodiments, the brake pad 900 may be used most effectively in a vehicle in a specific braking position. In such embodiments, brake pads may be used in tandem arrangements to provide effective braking at all wheels of the vehicle, each brake pad having a specialized design suitable for its particular position when installed in the vehicle, without deviating from the teachings disclosed herein.

[0028] In some embodiments, the application of the surface coating 109 can produce a geometric pattern. Fig. Figure 10 is a representation of a brake pad 1000 which uses the same carrier plate 101, the same friction lining 105 and the same formulation of the surface coating 109 as the brake pad 100, but in which the application of the surface coating 109 forms a geometric pattern comprising a grid of hexagons. Fig. Figure 11 is a representation of a brake pad 1100 which uses the same carrier plate 101, the same friction lining 105 and the same formulation of the surface coating 109 as the brake pad 100, except that the application of the surface coating 109 forms a geometric pattern comprising a repeating pattern of hexagons. Further embodiments may include further designs or further embodiments without departing from the teachings disclosed herein.

Claims

[1] Brake lining (100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100) comprising: a support plate (101) with a mounting surface (103), a friction lining (105) attached to the mounting surface (103) and having a tribological surface (107) which runs parallel to the mounting surface (103) within a specified tolerance; and a surface coating (109) which is attached to a part of the tribological surface (107) using an adhesive and which, when viewed in a direction perpendicular to the tribological surface (107), has a predetermined circumferential shape, wherein the tribological surface (107) of the friction lining (105) is configured to transmit frictional forces to a brake disc, wherein the surface coating (109) is a composite material, the composite material containing potassium titanate and further configured to create a transfer layer on the brake disc [2] Brake pad (100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100) according to claim 1, wherein the composite material contains at least two different potassium titanates [3] Brake pad (100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100) according to claim 1, wherein the surface coating (109) is visually distinct from the friction lining (105). [4] Brake pad (100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100) according to claim 1, wherein the adhesive has a curing time which is not greater than 180 seconds within a specified tolerance [5] Brake pad (100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100) according to claim 1, wherein the surface coating (109) is applied to the tribological surface (107) using an embossing process. [6] Brake lining (100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100) according to claim 1, wherein the composite material comprises a material component which is also present in the friction lining (105). [7] Brake pad (100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100) according to claim 1, wherein the composite material comprises at least two materials selected from a list including inorganic resin, organic resin, sodium silicate, polyblend of unground potting compound, zirconium dioxide, zirconium, barite, antimony trisulfide and magnetite [8] Brake pad (100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1100) according to claim 1, wherein the predetermined circumferential shape is located on a part of the tribological surface (107) which has a higher frequency of contact with a brake disc during operation

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