Brake pad unit, composite back plate and back plate manufacturing method

Abstract

The invention discloses a manufacturing method of a back plate. The back plate is used for bearing a friction material to form a brake pad unit of a disc brake assembly. The method includes molding a composite backing plate precursor within a mold such that one side of the backing plate is configured to define a friction material mounting surface of a molded engagement feature. A composite backing plate for carrying a friction material to form a brake pad unit of a disc brake assembly is also disclosed. In addition, the invention further discloses a brake pad unit comprising the composite back plate.

Description

Technical Field

[0001] The present invention relates to a composite back plate, a brake pad unit and a method for manufacturing the back plate. In particular, the composite back plate is used for a disc brake assembly. Background Art

[0002] Disc brake assemblies. As assemblies used in motor vehicles, for example, among many other examples, typically include a rotor. The rotor is a circular disk in a disc brake assembly that rotates as the wheel to which it is mounted rotates. A brake pad unit of the disc brake assembly contacts the rotor during braking, inhibiting the rotor from rotating through the action of friction. The brake pad unit may include a friction material disposed on a backing plate, wherein the friction material is in direct contact with the rotor.

[0003] Traditional automotive brake pads consist of friction material bonded to a mild steel backing plate. To reduce the weight of the brake pad, various improvements have been made to the design of the steel backing plate.

[0004] Brake pad units are subject to a number of tests related to their durability and performance, which may vary depending on regulations in different regions. An example of a test is the shear test, which involves the strength of the bond between the friction material and the backing plate.

[0005] When considering alternative structures for brake pad unit components, these alternative structures need to be able to pass various durability and performance tests. For example, a simple stamped stainless steel plate alternative structure can be used as a back plate to reduce the weight of the brake pad unit. Ideally, for example, the alternative structure should be able to be developed without requiring completely different manufacturing equipment or methods and pass various durability and performance tests. Summary of the invention

[0006] The following aspects of the present disclosure provide technical solutions for improving the bonding between a composite backing plate and a friction pad of a brake pad unit. The disclosed features generally provide a stronger bond between the backing plate and the friction pad. Preferably, the features of the present disclosure improve the resistance of the brake pad unit to shear forces (e.g., forces that push the friction pad to slide on the backing plate or potentially disengage). In the examples described herein, the backing plate can be a multi-material solid polymer composite material composed of non-metallic fibers and a non-metallic polymer matrix (e.g., containing a non-metallic resin and / or as a binder).

[0007] According to a first aspect of the present disclosure, a method for manufacturing a back plate is provided, the back plate being used to carry friction material to form a brake pad unit of a disc brake assembly. The method comprises: forming the back plate from a composite back plate precursor so that the back plate comprises a first side and a second side spaced apart along a first axis, wherein forming the back plate comprises: molding the composite back plate precursor in a mold so that the first side of the back plate is configured as a brake mounting surface for engaging with a back plate mounting structure of the disc brake assembly; and molding the composite back plate precursor in a mold so that the second side is configured as a friction material mounting surface and a molded engagement feature is defined, wherein the friction material mounting surface is defined by an extended reinforcing fiber layer, the extended reinforcing fiber layer extending from a first edge wall position of the back plate to a second edge wall position of the back plate, the edge wall being perpendicular to the first axis; a first portion of the friction material mounting surface including the molded engagement feature is offset by a first offset amount relative to a plane of the back plate along the first axis direction, and a second portion of the friction material mounting surface not including the molded engagement feature is offset by a second offset amount relative to the plane of the back plate along the first axis direction; the first offset distance is different from the second offset distance.

[0008] Optionally, the moulded engagement features are: moulded engagement features of a first type configured to extend into the friction material in use; or moulded engagement features of a second type configured to receive the friction material in use.

[0009] Optionally, the first type of molded engagement features include protrusions protruding from the friction material mounting surface; and the second type of molded engagement features include grooves extending into the backing plate but not through it.

[0010] Optionally, the mold comprises a press plate, the press plate comprising a press surface, the press surface comprising surface features corresponding inversely to the molded engagement features.

[0011] Optionally, forming the backplate includes: placing a composite backplate precursor in a mold; placing the mold in a heated press, setting its temperature high enough to allow a polymer matrix in the composite backplate precursor to flow; and compressing the mold to: compress the composite backplate precursor to provide flow in the polymer matrix; and press a pressing surface of the pressing plate into the composite backplate precursor to mold the engagement features into the friction material mounting surface.

[0012] Optionally, the method further comprises: using a release agent during molding to prevent the composite backsheet precursor from adhering to the mold and facilitating release of the backsheet from the mold; and soaking the backsheet with a solvent to remove the release agent transferred to the composite of the backsheet during molding.

[0013] Optionally, the method further comprises: subjecting the backing plate to a heating cycle to remove the solvent.

[0014] Optionally, the method further comprises: roughening the friction material mounting surface to increase its roughness.

[0015] Optionally, the method further comprises: coating an adhesive layer on the friction material mounting surface; and performing a drying process to dry the adhesive layer.

[0016] Optionally, the adhesive layer comprises: a mixture of nitrile phenolic adhesive and water.

[0017] Optionally, the mold engagement feature includes a planar surface offset from the plane of the back plate in a direction perpendicular to the plane of the back plate, wherein the planar surface is parallel to the plane of the back plate.

[0018] Optionally, the molded engagement feature defined by the friction material mounting surface is a portion of the extended reinforcement fibers, and the extended reinforcement fibers of the extended reinforcement fiber layer extend in a continuous manner between the molded engagement feature and the remainder of the friction material mounting surface.

[0019] According to a second aspect of the present invention, a composite back plate is provided for carrying friction material to form a brake pad unit of a disc brake assembly, the composite back plate comprising a first side and a second side spaced apart along a first axis: wherein: the composite back plate is made of a composite material containing reinforced fibers, and the composite material is distributed throughout the composite back plate; the first side defines a brake mounting surface for engaging with a back plate mounting structure of the disc brake assembly; the second side is a friction material mounting surface, which defines a molded engagement feature, and the molded engagement feature is molded into the friction material mounting surface, wherein: the friction material mounting surface is defined by an extended reinforced fiber layer, the extended reinforced fiber layer extends from a first edge wall of the back plate to a second edge wall of the back plate, the edge is perpendicular to the first axis, a first portion of the friction material mounting surface containing the molded engagement feature is offset by a first offset relative to the back plate plane along the first axis direction; an area of ​​the friction material mounting surface that does not contain the molded engagement feature is offset by a second offset relative to the back plate plane along the first axis direction; the first offset is different from the second offset.

[0020] Optionally, in the composite back plate according to the second aspect, the molded engagement feature is in the form of: a first type of molded engagement feature configured to extend into the friction material when in use; or a second type of molded engagement feature configured to accommodate the friction material when in use.

[0021] Optionally, in the composite back plate according to the second aspect: the first type of engagement feature comprises a protrusion protruding from the friction material mounting surface; and the second type of engagement feature comprises a groove extending into but not penetrating the back plate.

[0022] Optionally, in the composite back plate according to the second aspect, the friction material mounting surface is defined by a plurality of molded engagement features, wherein: at least one of the plurality of molded engagement features is of the first type; and / or at least one of the plurality of molded engagement features is of the second type.

[0023] Optionally, in the composite back plate according to the second aspect, the friction material mounting surface defining the molded engagement feature is part of the extended reinforcement fiber layer, and the extended reinforcement fibers of the extended reinforcement fiber layer continuously extend between the molded engagement feature and the rest of the friction material mounting surface.

[0024] Optionally, in the composite back plate according to the second aspect, the friction material mounting surface is covered with an adhesive layer, and the adhesive layer is used to bond the friction material to the friction material mounting surface.

[0025] Optionally, in the composite backplane according to the second aspect, the mold engagement feature comprises a flat surface that is offset by a first offset relative to the backplane plane in a direction perpendicular to the backplane plane, and the flat surface is parallel to the backplane plane.

[0026] According to a third aspect of the present disclosure, a brake pad unit for a disc brake assembly is provided, the brake pad unit comprising a composite backing plate according to the second aspect and a friction pad, wherein: the friction pad comprises a friction material bonded to the friction material mounting surface; and the friction pad comprises a mating feature which corresponds inversely to the molded engagement feature, and the mating feature engages with the molded engagement feature. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Examples of the present disclosure will be described with reference to the accompanying drawings, in which:

[0028] Figure 1 is a flow chart of a backplane manufacturing method according to an example;

[0029] Figure 2A is a schematic perspective view of a first back plate according to an example;

[0030] Figure 2B is a schematic plan view of a first backing plate according to an example;

[0031] Figure 2C is a schematic side cross-sectional view of a first backing plate according to an example;

[0032] Figure 2D is a schematic side cross-sectional view of a first backing plate and a friction pad according to an example;

[0033] Figure 3A is a schematic perspective view of a second back plate according to an example;

[0034] Figure 3B is a schematic plan view of a second backing plate according to an example;

[0035] Figure 3C is a schematic side cross-sectional view of a second backing plate according to an example;

[0036] Figure 4A is a schematic perspective view of a third back plate according to an example;

[0037] Figure 4B is a schematic plan view of a third backplane according to an example;

[0038] Figure 4C is a schematic side cross-sectional view of a third backing plate according to an example;

[0039] Figure 5 is a schematic side view of a mold according to an example;

[0040] Figure 6 is a schematic plan view of a first fiber layer according to an example;

[0041] Figure 7 is a schematic perspective view of a first example of a first fiber layer according to an example;

[0042] Figure 8 is a schematic perspective view of a second example of a first fiber layer according to an example;

[0043] Fig. 9 is a schematic plan view of a second fiber layer according to an example;

[0044] Fig.10 is a schematic perspective view of a first example of a second fiber layer according to an example;

[0045] Fig.11 is a schematic perspective view of a second example of a second fiber layer according to the example;

[0046] Fig.12 is a schematic plan view of a third fiber layer according to an example;

[0047] Fig.13 is a schematic perspective view of a third fiber layer according to an example;

[0048] Fig.14 is a schematic exploded perspective view of a first brake pad unit according to an example;

[0049] Fig.15 is a schematic perspective view of a first brake pad unit according to an example;

[0050] Fig.16 is a schematic perspective view of a second brake pad unit according to an example;

[0051] Fig.17 is a schematic perspective view of a third backing plate showing extended reinforcing fibers according to an example. DETAILED DESCRIPTION

[0052] The present disclosure relates to a method for manufacturing a back plate for a disc brake assembly, a composite back plate, and a brake pad unit including the composite back plate. The back plate according to the present disclosure can constitute a part of a brake pad unit of a disc brake assembly when in use. The disc brake assembly can be used, for example, in an automobile or other vehicle.

[0053] As will be appreciated by those skilled in the art, a disc brake assembly typically includes at least one rotor that rotates in sync with the wheel to which the disc brake assembly is mounted. The back plate of the disc brake assembly supports a friction material that contacts the rotor during braking. Contact with the friction material will inhibit rotation of the rotor through friction. For example, kinetic energy of the vehicle will be absorbed by the friction material in the form of heat energy and dissipated in the form of, for example, acoustic energy.

[0054] The back plate may be engaged with a back plate mounting structure of a disc brake assembly. For example, the back plate mounting structure is a caliper assembly configured to press the brake pad unit against the rotor to achieve braking. For example, the caliper may be hydraulically or electrically actuated. Further details about the disc brake assembly are not described herein and are known to those skilled in the art.

[0055] The brake pad unit according to the present disclosure can be adapted to existing disc brake assemblies and is suitable for conventional disc brake assembly designs, including but not limited to regenerative braking systems. The brake pad unit can be assembled in combination with other common components of a disc brake assembly, such as a wear sensor for monitoring the remaining service life of the unit.

[0056] Figure 1 1 is a flow chart of a method 100 for manufacturing a back plate of a disc brake assembly. The method 100 includes forming the back plate from a composite back plate precursor such that the back plate includes a first side and a second side spaced apart from each other along a first axis. For example, the first axis is a thickness axis of the back plate. In other words, the thickness of the back plate extends along the first axis. For simplicity, the first axis is referred to as the thickness axis hereinafter.

[0057] Figure 1 The flowchart of FIG. 1 shows the steps involved in forming a backplane according to method 100. It should be noted that Figure 1 Various aspects of method 100 are merely illustrated, and the specific order of execution of the disclosed operations is not limited.

[0058] In step 102 of method 100, a composite back plate precursor is compression molded in a mold so that a first side of the back plate is configured as a brake mounting surface for engaging with a back plate mounting structure of a disc brake assembly. In step 104 of method 100, the composite back plate precursor material is compression molded in a mold so that the second side is configured as a friction material mounting surface. The compression molding of step 104 includes molding engagement features defining molded engagement features on the friction material mounting surface. Some process steps may be performed in parallel, some process steps may be performed sequentially, and some process steps may be performed in a different order than described herein. For example, the compression molding described in steps 102 and 104 may be performed simultaneously with the compression molding of the composite back plate precursor in the mold.

[0059] The molded engagement features are molded during the back plate forming process. In other words, the friction material mounting surface is molded in the mold to define the molded engagement features. In other words, the engagement features are molded into the friction material mounting surface. For simplicity, the molded engagement features may be referred to as engagement features. Therefore, it should be understood that the "engagement features" referred to herein refer to engagement features formed by molding.

[0060] For example, by molding the engagement features on the friction material mounting surface, the internal structural integrity of the material layer on which the friction material mounting surface is located can be maintained. For example, compared to forming the structure by mechanical processing such as scraping, cutting, drilling, etc., the molding process can better maintain the structure of the layer (e.g., the arrangement structure of the fibers inside the layer). The beneficial effects of the molded engagement features will be further described below.

[0061] The friction material mounting surface is composed of an extended reinforcing fiber layer extending from a first edge wall position of the back plate to a second edge wall position of the back plate, and the edge wall is substantially parallel to the thickness axis (within an allowable tolerance range). In other words, the edge wall of the back plate is substantially perpendicular to the first side, for example, as described below. The composite back plate may include one or more different composite layers. For example, when it is mentioned that the fibers in a particular layer extend between the edge wall positions, it should be understood that the fibers extend between the edge wall positions of the corresponding layer to which they belong. For example, the extended reinforcing fibers can extend in a continuous manner from one side of the back plate to the opposite side of the back plate. The characteristics of the extended reinforcing fibers will be described in more detail below.

[0062] In particular, in step 104, the friction material mounting surface is configured by a molding process such that a first portion of the friction material mounting surface including the molded engagement feature is offset by a first offset relative to a backing plate plane along a first axis (i.e., a thickness axis). The backing plate plane is a plane perpendicular to the thickness axis, as described below. In an example, a second portion of the friction material mounting surface not including the engagement feature is offset by a second offset relative to the backing plate plane along the thickness axis. In an example, the first offset is different from the second offset.

[0063] In some examples, the engagement feature is a protrusion extending from a portion of the friction material mounting surface without an engagement feature. In other examples, the engagement feature is a groove that extends into the backing plate but does not penetrate through. The groove is, for example, formed in the friction material mounting surface. The engagement feature forms a significant topological feature on the friction material mounting surface. The friction material can be molded into the disclosed backing plate so that the friction pad includes a mating feature that corresponds inversely to the molded engagement feature, and the mating feature and the molded engagement feature are mutually engaged. This engagement structure allows the backing plate and the friction pad to interlock, thereby effectively inhibiting movement of the friction pad relative to the friction material mounting surface.

[0064] In an example, the friction material mounting surface includes one or more engagement features. The engagement features are used to engage with the friction material mounted on the friction material mounting surface, so that the backing plate and the friction pad formed by the friction material are better bonded to resist shear forces. For example, a brake pad unit with a backing plate that does not include one or more engagement features may not be able to withstand higher shear forces than a brake pad unit including the backing plate described in the present disclosure.

[0065] An example of a backplane structure obtained by executing the method 100 is as follows: Figures 2A-2D , Figures 3A-3C and Figures 4A-4C For example, the method 100 may be performed to produce a composite backplane including the first side and the second side as described below.

[0066] against Figure 1 Having illustrated the example and method 100 , more specific processes that may form part of the method 100 will now be described. Figure 5 5 is a schematic cross-sectional side view of a mold 500 according to an example, which can be used to perform the molding process. The mold 500 is a tool for molding a precursor material to produce a target product.

[0067] In these examples, mold 500 includes a press plate 502. The press plate 502 includes a press surface 504 that includes complementary surface features 506 that are the inverse counterparts of the molded engagement features in any of the examples described herein. Figure 5 In the specific example, a plurality of complementary surface features 506 are provided. For example, protrusions and / or grooves are formed on the pressing surface 504 to define the complementary surface features 506. It should be noted that, Figure 5 The complementary surface features 506 shown are merely illustrative examples and do not necessarily correspond to complementary features of the specific mold engagement feature examples described herein.

[0068] For example, method 100 also includes arranging a composite backplane precursor 508 in mold 500. For simplicity, the composite backplane precursor 508 is referred to as precursor 508 below. The precursor 508 is a material used to form a backplane. The backplane is made of a composite material containing reinforcing fibers, and the composite material is distributed throughout the entire composite backplane (for example, the backplane does not contain metal). For example, the backplane contains reinforcing fibers and a polymer matrix. For example, the backplane may include a polymer matrix, which may include a resin and / or a polymer matrix as an adhesive. In some examples, the polymer matrix is ​​a phenolic resin family resin; in other examples, the polymer matrix is ​​a polyaryletherketone (PAEK) family thermoplastic polymer. For example, the precursor 508 may be in a state where the polymer matrix has not yet been cured, and once the polymer matrix is ​​cured, the backplane can be formed.

[0069] As mentioned above, the backboard includes an extended reinforced fiber layer (see below for details) Figures 6 to 11 ). The extended reinforcing fiber layer is a composite layer. For example, the precursor 508 includes one or more material compositions and / or structures configured according to one or more composite layer structures required to form a portion of the backplane. For example, the precursor 508 includes an extended reinforcing fiber layer precursor. The extended fiber layer precursor can be simply referred to as an extended fiber precursor.

[0070] For example, the extended fiber precursor used to form the extended reinforcing fiber layer can be a pre-impregnated fiber layer ("prepreg"). It should be understood by those skilled in the art that the pre-impregnated fiber layer comprises fibers and a partially cured polymer matrix (e.g., containing resin and / or as an adhesive), and the pre-impregnated fiber layer belongs to the B-stage material. For example, the pre-impregnated fiber layer comprises a reinforcing fiber fabric and a partially cured polymer matrix. In some examples, the extended fiber precursor can be non-pre-impregnated and instead prepared by laying the reinforcing fibers on site and injecting the uncured / partially cured polymer matrix into the fibers. It should be understood that in order to obtain an extended reinforcing fiber layer, the extended fiber precursor needs to have a specifically arranged extended fiber structure.

[0071] In some examples, the precursor 508 includes an extended fiber precursor for forming a friction material mounting surface in addition to precursors for one or more other layers. For example, the backing plate may include multiple composite material layers. In some examples, the backing plate may include more than one composite material layer of the same type. In some examples, the backing plate includes at least two different types of composite material layers.

[0072] For example, the back panel may include a reinforcing fiber layer that does not extend between the edge wall positions of the back panel after the back panel is formed (see below for details). Fig.12 and Fig.13). For example, such a reinforcing fiber layer may be referred to as a non-extended fiber layer, and the precursor of the layer may be referred to as a non-extended fiber precursor. For example, the non-extended fiber layer is a composite layer. In these embodiments, the non-extended fiber precursor also comprises a polymer matrix, wherein the polymer matrix comprises a resin and / or acts as a binder.

[0073] In some examples, the overall precursor 508 can be configured to define multiple layers. For example, a structure in which two extended reinforcing fiber layers sandwich a non-extended fiber layer can be used. Depending on the desired structure, any number and arrangement of such fiber layers can be used, and the precursor 508 is arranged accordingly. Several exemplary layers included in the back panel will be further described below.

[0074] As described above, the method includes placing the backplane precursor 508 in the mold 500. In some examples, the mold 500 is placed in a heated press, and the temperature of the heated press is set high enough to cause the polymer matrix contained in the precursor 508 to flow. In some examples, the heated press includes heated platens that provide a force to press the platen 502. For example, when the mold 500 is placed in the heated press, one platen contacts the platen 502 and the other platen contacts the mold base 510 ( Figure 5 Platen not shown). In some examples, for different layers of multiple different layer precursors as part of the backplane precursor 508, each layer precursor may contain the same or different polymer matrices that can be molded and cured under the same conditions.

[0075] For example, the precursor 508 is compressed by a compaction mold 500 (i.e., a heated press applies pressure to the compression mold) to cause the polymer matrix to flow. At the same time, the compaction mold 500 can press the pressing surface 504 of the press plate 502 into the precursor 508, thereby molding a bonding feature on the friction material mounting surface. In some examples, the compaction process is implemented after the precursor 508 is fully heated to the target temperature. For example, once the precursor 508 is fully heated, the polymer matrix can be fully flowed to achieve the desired molding effect. The heated press can apply a suitable compression force. For example, a suitable compression force can be at least 2 tons / square inch or about 31 MPa. In other examples, different pressures suitable for back plate molding can also be used.

[0076] In these examples, inducing the polymer matrix to flow can cause the precursor 508 to conform to the cavity of the compaction mold 500. For example, heat provided by a heated press can also help the precursor 508 conform to the cavity of the compaction mold 500. The compressive force and / or heat in this process can cause the polymer matrix to complete curing.

[0077] All disclosed examples may also include a post-curing thermoforming process, including keeping warm at a first temperature. The post-curing forming may include a procedure of gradually increasing the temperature for a predetermined time and maintaining the high temperature state. For example, the molded precursor 508 may be post-cured thermoforming, including continuous keeping warm at a high temperature (e.g., 150°C for at least 3 hours, preferably 170°C and above for 1 to 30 hours). For example, post-curing thermoforming of the backplane can improve its thermal stability. The post-curing cycle includes multiple gradient temperature increases and keeping warm. The post-curing cycle may include controlled cooling.

[0078] In some examples, the method 100 may include using a release agent during the molding process to prevent the composite backsheet precursor 508 from sticking to the mold and to assist in demolding the backsheet. For example, the release agent is applied between the precursor 508 and the relevant inner surface of the mold 500. The advantage of using a release agent is that when the backsheet needs to be removed from the mold 500 after the molding process is completed, the target molding structure of the composite backsheet can be avoided from being damaged or damaged.

[0079] In some examples, the method 100 includes roughening the friction material mounting surface 210 to increase its surface roughness. For example, the roughening process can be performed after the backing plate is completed and cured and thermoformed. For example, the roughening process can include sandblasting, shot peening, or glass bead impacting the friction material mounting surface. The friction pad (formed by the friction material) is bonded to the friction material mounting surface by an adhesive (as described below) between the friction material and the friction material mounting surface. Roughening the friction material mounting surface can form a rough surface with a larger surface area for such an adhesive, thereby forming a stronger bond.

[0080] In some examples, method 100 also includes a soaking treatment process for the backplane with a solvent. The soaking treatment is used to remove the release agent that penetrates into the composite material of the backplane during the molding process. In some examples, when the aforementioned roughening treatment is implemented, the soaking treatment can also be used to remove composite material particles and other materials remaining from the roughening process. In some examples, the solvent used may be propanol, isopropanol, methanol, toluene, acetone, etc. In some examples, the solvent needs to be removed from the composite backplane. In some examples, the backplane can be subjected to a heating cycle to remove volume. For example, the temperature at which the backplane is heated depends on the boiling point of the solvent used. As a specific example, the backplane is placed in an 80°C oven and heated for about a given time to ensure that the solvent is completely evaporated. For example, the given time can be about one hour.

[0081] In some examples, method 100 includes applying an adhesive layer to the friction material mounting surface. Thus, a backing plate having a friction material mounting surface covered with an adhesive layer can be provided, wherein the adhesive layer is used to bond the friction material to the friction material mounting surface. For example, the adhesive layer can include a mixture of a nitrile phenolic adhesive and water. In some such examples, the adhesive layer includes a mixture of 66% nitrile phenolic adhesive, 24% water and 10% phenolic varnish. The proportions of each component can be adjusted according to the performance requirements of the adhesive. Generally, any suitable adhesive that can withstand the high operating temperature of the backing plate and achieve a firm bond between the friction pad and the backing plate (such as in accordance with relevant standards) can be used. For example, an adhesive that can maintain good bonding integrity at high temperatures of 350°C and above. For example, the adhesive can be selected based on the backing plate material and / or the friction material. In the example, when the backing plate and / or the friction material is phenolic resin-based, an adhesive compatible with it should be selected.

[0082] In some examples, method 100 further includes performing a drying process to dry the adhesive layer. For example, a heating process is applied to the adhesive layer for a certain period of time. As a specific embodiment, the adhesive layer can be kept at 80°C for the time period. The temperature can be based on the adhesive ratio used. For example, the given time period can be 40 minutes to 1 hour depending on the adhesive ratio used.

[0083] In some examples, the backing plate manufactured according to the embodiments of the above method is used for mounting a friction material thereon. In some embodiments, the friction material can be molded on the backing plate to form a friction pad. Thus, a brake pad unit including a composite backing plate of any embodiment of the present disclosure can be obtained, wherein the friction pad includes: a friction material bonded to a friction material mounting surface, and a mating feature that is oppositely corresponding to and meshes with the molded engagement feature.

[0084] Those skilled in the art will appreciate that friction materials can typically be molded onto conventional backing plates. Therefore, the composite backing plates disclosed herein can be used in conventional processes for attaching friction pads, thereby avoiding the capital and other resource costs associated with replacing conventional backing plates (e.g., stamped steel backing plates) with the backing plates described herein. At the same time, the disclosed bonding features formed in the extended reinforcement fiber layer can provide desired mechanical properties, such as shear strength.

[0085] For example, a method of mounting a friction material to a friction material mounting surface may include molding a friction pad onto a backing plate with the friction material (as a pad precursor). For example, the starting point may be a backing plate made as in the previous example, whose friction material mounting surface already has a dry adhesive layer. For example, the backing plate is placed in a molding tool for molding friction material (hereinafter referred to as a friction material molding tool). The friction material may be introduced so that it is positioned on the adhesive layer, and the adhesive layer is applied to the friction material mounting surface of the friction material molding tool. Pressure is then applied, and optionally heat is applied, to mold the friction material and cure the adhesive layer, thereby forming a friction pad bonded to the friction material mounting surface via the adhesive layer.

[0086] In some examples, the friction material comprises carbon. In some examples, the friction material comprises a polymer matrix. In some examples, the friction material is a granular powder. In some examples, the friction material is a phenolic resin matrix.

[0087] For example, when the friction material is molded on a friction material mounting surface having an engagement feature, the resulting friction pad will include a structure that interlocks with the engagement feature, which advantageously provides better shear resistance. In some examples, the shear strength of the resulting brake pad unit is greater than 4.5 MPa; in other examples, the shear strength of the resulting brake pad unit is greater than 9 MPa. For example, the methods described herein can provide a composite backing plate brake pad unit that meets various shear strength standards.

[0088] An example of a composite backplane structure manufactured by the example of the above method is now described. FIG. 2A to FIG. 2C A specific example 200 involving a backplane, FIG. 2A to FIG. 2C The backplane examples shown in the drawings are all labeled 200. According to the specific example: Figure 2A is a schematic three-dimensional diagram of the first back plate 200, Figure 2B is a schematic plan view of the first backplane 200, Figure 2C is a schematic side cross-sectional view of the first back plate 200 . Figure 2C The cross section shown is along Figure 2B Intercept the marked AA line.

[0089] The back plate may be flat. For example, the first back plate 200 has a sheet-like basic form and is planar as a whole (ie, the first back plate 200 mainly exists in a certain plane, and its thickness is significantly smaller than the extension dimension in the plane). For example, the plane is perpendicular to the thickness axis.

[0090] In these examples, the first backing plate 200 includes a first side 202 and a second side 204. The first side 202 and the second side 204 provide surfaces on opposite sides of the first backing plate 200. The thickness axis is as shown in FIG. Figure 2C As shown by the double-headed arrow marked 206. Figure 2CIt can be seen that the first side 202 and the second side 204 are spaced apart relative to the thickness axis 206 .

[0091] The backplane plane mentioned above is a plane perpendicular to the thickness axis 206. Figure 2C In the orientation, the backplane plane, for example, extends in the inside-out direction of the drawing and in the left-right direction of the schematic diagram. The backplane plane is indicated by a mark 208. The backplane plane 208 does not extend along the thickness axis 206. Figure 2B In the plan view of the first back plate 200 shown, the back plate plane 208 is located in the plane of the drawing, extending in the left-right and up-down directions, but not in the inside-outside direction of the drawing. The back plate plane 208 is an imaginary plane that can be used to describe the position and orientation of various features. The position of the back plate plane 208 along the thickness axis can be any position, which can be arbitrary in this description.

[0092] In these examples, the second side 204 is configured as a friction material mounting surface 210. The friction material mounting surface 210, for example, defines a molded engagement feature 212. FIG. 2A to FIG. 2C In the example of the first backing plate 200 shown, a plurality of engagement features are included. In an example, a backing plate according to the present disclosure may include one or more molded engagement features defined by a friction material mounting surface. For simplicity, the following description is made of Figures 2A to 2C In this example, reference numeral 212 is used to collectively refer to all engagement features.

[0093] Figure 2C , a portion of a first portion 214 of a molded engagement feature 212 is indicated as being defined by the friction material mounting surface 210 and offset by a first offset 216 relative to the backing plate plane 208 along the thickness axis 206. In this example, all engagement features 212 are similar to one another, and the first portion 214 includes all engagement features 212. However, for simplicity of illustration, Figure 2C Only a portion of the first portion 214 including one engagement feature 212 is labeled. Figure 2C A portion of the second portion 218 of the friction material mounting surface 210 that does not include the engagement feature 212 is indicated. In these examples, the second portion 218 includes all portions of the friction material mounting surface 210 that do not include the engagement feature.

[0094] In these examples, Figure 2C As shown, the second portion 218 is offset relative to the backing plane 208 along the thickness axis 206 by a second offset 220. In these examples, the first offset 216 is greater than the second offset 220. Thus, a patterned or textured structure is defined on the friction material mounting surface.

[0095] In some examples, a first type of molded engagement feature is provided that is configured to extend into the interior of the friction material when in use. For example, the first type of engagement feature may include a protrusion that protrudes from the friction material mounting surface 210. In some examples, such as in Figures 2A to 2C As shown in FIG. , all molded engagement features 212 are in the form of protrusions (see, for example, Figure 2A These molded engagement features 212 are Figures 2A to 2C In the example of the first type shown in FIG. 2 , for example, when the friction material is mounted to the friction material mounting surface 210 , the first type of engagement features will extend into the friction material to form a structure similar to penetrating the friction material.

[0096] Figure 2D 3D shows an example of a brake pad unit according to the present disclosure, for example, when the friction pad 222 is mounted on the back plate, it has a proximal end 224 and a distal end 226. The proximal end 224 is a side close to the back plate, and the distal end 226 is an opposite side away from the back plate. The first type of engagement feature extends into the friction pad 222, so that the engagement feature is closer to the distal end 226 than the portion of the proximal end 224 closest to the back plate. For example, the friction pad 222 has a matching feature that is oppositely corresponding to the molded engagement feature and is mutually engaged with the molded engagement feature. For example, the back plate and the friction pad are interlocked by the engagement feature. The interlocking enhances the resistance to shear forces, such as the direction indicated by arrow 232.

[0097] Alternatively or additionally, one or more second type engagement features may be provided that are configured to receive the friction material when in use. For example, the second type engagement features may include grooves that extend into the interior of the back plate but do not extend through it. In some examples, the friction material mounting surface is defined with a plurality of molded engagement features, wherein at least one of the plurality of molded engagement features is of the first type and / or at least one of the plurality of molded engagement features is of the second type.

[0098] Figure 3A is a schematic perspective view of a second back plate 300 according to an example, Figure 3B 3 is a schematic plan view of a second back plate 300 according to an example. The difference between the second back plate 300 of the example and the first back plate 200 of the example is that the second back plate 300 includes a plurality of molded joint features 312 of the second type instead of the first type, and the remaining features are similar to those of the first back plate 200, and the same method is used. Figures 2A to 2D The same reference numerals are used.

[0099] Figure 3C For along Figure 3B BB line is shown as a schematic side cross-sectional view of the second back plate 300. In these examples, the second portion 218 without a bonding feature (in Figure 3C In the orientation) relative to the second type molded engagement feature 312. In contrast, in Figure 2C In the example of Figure 2C The engagement features 312 are not extended to the first side 202 of the back plate. In the example, the friction material is contained in the second type of engagement features 312. For example, a similar Figure 2D The friction pad shown is mounted on the second back plate 300 ( Figure 3C not shown) to form a brake pad unit.

[0100] As described above, a backing plate may be provided having a combination of first and second types of engagement features. Figure 4A is a schematic perspective view of a third back plate 400 according to an example. Figure 4A The molded engagement features of the third back plate 400 are Figures 2A to 2D The first back plate 200 and Figures 3A to 3C The second backplane 300 shown is different. Figure 4B is a schematic plan view of a third back plate 400 according to an example. In this example, the third back plate 400 includes a first set of molded engagement features 412a and a second set of molded engagement features 412b. The first set of molded engagement features 412a includes a first type of engagement features 412a (protrusion structures in this example). In these examples, the second set of engagement features 412b includes a second type of engagement features 412b. In these embodiments, a first portion 214 is provided, which is a portion of the friction material mounting surface 210 that defines the first set of engagement features 412a. A second portion 218 is also provided, which is a portion of the friction material mounting surface 210 that does not include any engagement features. In these examples, the first offset 216 is greater than the second offset 220.

[0101] In these examples, a third portion 402 of the friction material mounting surface 210 is also provided, which includes a second set of engagement features 412b. In such examples, either the portion including the first set of engagement features 412a or the portion including the second set of engagement features 412b may be referred to as the "first portion", while the other portion including the engagement features is referred to as the "third portion".

[0102] In these examples, the third portion 402 of the friction material mounting surface 210 is offset in the thickness direction relative to the backing plate plane 208 by a third offset 404 that is different from both the first offset 216 and the second offset 220. In these examples, the third offset 404 is less than the first offset 216 and less than the second offset 220.

[0103] For example, you can use something like Figure 2DThe friction pad shown is mounted on the third back plate 400 ( Figure 4C not shown) to form a brake pad unit.

[0104] The engagement feature according to any example can form an interlocking engagement structure with the friction pad when it is mounted to the friction material mounting surface, thereby enhancing the shear resistance performance. In addition, the engagement feature also has the advantage of increasing the surface area bonded to the friction pad, thereby improving the bonding strength between the backing plate and the friction pad.

[0105] Various examples of molded engagement features are described above. However, it should be noted that these are only specific examples, and the shapes of the first or second type of engagement features are not limited thereto. For example, Figures 2A to 2D and Figures 4A to 4C The first type of engagement feature shown has a circular cross-section in plan view. However, in other examples, the first type of engagement feature can have a different shape (e.g., rectangular, triangular, hexagonal, or any shape that can be molded to the second side 204 by the methods described herein). In some examples, the molded engagement feature includes a flat surface that is offset relative to the backplane plane 208 in a direction perpendicular to the backplane plane (e.g., in the thickness direction), and the flat surface is parallel to the backplane plane. For example, Figures 2A to 2D The first back plate 200 includes a bonding feature 212, whose top surface 225 is parallel to and offset from the back plate plane 208. For example, Figures 3A to 3C The second back plate 300 includes a bonding feature 312, which is parallel to the back plate plane 208 at the bottom surface 302 of the groove. Figure 4C As shown, Figures 4A to 4C The third backing plate 400 includes a planar surface that is also parallel to the backing plate plane 208 as part of each engagement feature.

[0106] In some examples, the provided engagement features do not include a flat surface parallel to the backplane plane 208. For example, in Figure 2C , 3C 4C , the engagement feature may have an arcuate cross-section (eg, an engagement feature that is molded as an arc-shaped protrusion on the friction material mounting surface 210 ), a triangle, or other shapes that do not form a flat surface parallel to the backing plate plane 208 .

[0107] As previously described, the friction material mounting surface 210 is defined by the extended reinforcing fiber layer. For example, the extended reinforcing fiber may extend throughout the entire back plate in a plane that is not parallel to the thickness axis. For example, in a Cartesian coordinate system, a second axis 228 perpendicular to the thickness axis and a third axis 230 perpendicular to the thickness axis may be set (see Figure 2B , 3B 4B). Although the back plate may take any shape (eg, for use in a disc brake assembly), for ease of description, the second axis may be referred to as the length axis and the third axis may be referred to as the width axis.

[0108] In these examples, the extended properties of the extended reinforcing fibers are manifested as the fibers extending across the entire span of the back panel along the length axis and / or the width axis. As previously described, the extended reinforcing fibers extend from a first edge wall position of the back panel to a second edge wall position of the back panel. The position of the extended reinforcing fibers relative to the thickness axis may also change as the position on the length axis and / or the width axis changes.

[0109] For the convenience of the following description, the extended reinforcing fiber layer forming the friction material mounting surface is referred to as a friction mounting extended fiber layer. The extended reinforcing fibers may form a variety of different arrangement patterns. In some examples, all the extended reinforcing fibers may be aligned with each other, so that the extended reinforcing fiber layer is similar to a fabric layer in which the fibers are arranged in the same direction. For example, the extended reinforcing fibers may be aligned along the length direction, the width direction, or the direction in which the values ​​of the length and width coordinate axes change simultaneously.

[0110] Figure 6 Schematic plan views of examples of friction-mounted extended fiber layers 600 (this particular extended reinforcement fiber layer includes engagement features for friction material to be mounted thereon). In these examples, the extended reinforcement fibers 602 extend between different locations of the edge wall 604. The edge wall 604 of the first friction material extended fiber layer 600 is a portion of the back plate edge wall. In these examples, the extended reinforcement fibers 602 extend throughout the entire length of the back plate (in the direction of the length axis 228), thereby achieving a fiber arrangement across the entire back plate.

[0111] For example, the extended reinforcement fibers 602 include first extended reinforcement fibers 602a extending from a first location 604a of the edge wall 604 to a second location 604b of the edge wall 604. In these examples, all fibers are longitudinally aligned in the same direction. The friction mounted extended fiber layer 600 may include one or more sub-layers. For example, each sub-layer may include a group of extended reinforcement fibers arranged in a specific direction. Figure 7 A schematic perspective view of a first example 600a of a friction mounted extended fiber layer 600 comprising a sub-layer of longitudinally extending fibers. Figure 8 A schematic perspective view of a second example 600b of a friction mounted elongated fiber layer 600 comprising a plurality of elongated fiber sub-layers 802, 804, 806 arranged in the same direction.

[0112] In some examples, the friction mounting extended fiber layer forming the friction material mounting surface includes: a first group of extended reinforcing fibers extending in a first direction, and a second group of extended reinforcing fibers extending in a second direction different from the first direction. In some examples, the first direction and the second direction may be substantially orthogonal. For example, the first group of fibers and the second group of fibers may be interwoven.

[0113] Fig. 9Schematic plan views of examples of friction mount stretch fiber layers 900. In these examples, the second friction mount stretch fiber layer 900 includes stretch fibers 902 woven into a fabric. Fig.10 A schematic perspective view of a first example 900a of a friction mounted extended fiber layer 900 comprising a sub-layer of woven fibers. Fig.11 A schematic perspective view of a second example 900b of a friction mounted extended fiber layer 900, the example comprising a plurality of woven fiber sub-layers 1102, 1104, 1106. In the example of fiber weaving, the fibers extend between two locations of the edge wall.

[0114] Please note that for the sake of simplicity, Figures 6 to 11 The joining features are not shown.

[0115] For example, extended reinforcing fibers are different from fibers having a length less than the smallest dimension of the backsheet. For example, fibers having a length less than the width of the backsheet (the distance along the width axis across the backsheet) are not considered extended reinforcing fibers. For example, the extended reinforcing fibers are also different from fibers that terminate at a non-edge wall location within the backsheet.

[0116] As mentioned above, the backsheet may include a layer of non-extended fibers. Fig.12 is a schematic plan view of a non-extended fiber layer 1200 including non-extended fibers 1202 according to an example. Fig.13 1 is a schematic stereogram of a non-extended fiber layer 1200 according to an example. It should be understood that the fibers contained in the non-extended fiber precursor are shorter and have a lower structural regularity than the extended fiber precursor. For example, the non-extended fiber precursor does not contain a fabric, but rather contains short fibers distributed in multiple directions in the non-extended fiber precursor. For example, the fibers in the non-extended fiber layer can be arranged in a random orientation. For example, the non-extended fiber layer is made of a composite material containing reinforcing fibers, wherein the reinforcing fibers are short enough so that the composite material can be molded into various shapes. Due to the unstructured nature of the non-extended fiber precursor, its moldability is better, so it can be called a molded composite. It should be understood by those skilled in the art that the fibers in the molded composite can also be called discontinuous fibers (for example, in addition to being called non-extended fibers) because of their shorter length. However, it should be understood that "discontinuous" does not mean that the fibers are broken, and the fibers themselves still maintain end-to-end continuity. Its "discontinuous" means, for example, that the fibers do not extend continuously from one side of the layer to the opposite side.

[0117] As mentioned above, the back plate may include multiple composite material layers. In some examples, the back plate may have a structure in which two extended reinforced fiber layers sandwich a non-extended fiber layer. For ease of description, Fig.14 is a schematic exploded perspective view of a first brake pad unit 1400 according to an example, Fig.151 is a schematic perspective view of a first brake pad unit 1400. In these examples, a back plate 1402 comprises a non-extended fiber layer 1200 sandwiched by two extended reinforcing fiber layers. In these examples, the extended reinforcing fibers are all arranged in the same direction. A friction pad 1404 is mounted on the friction-mounted extended fiber layer 600b (engagement features not shown). Fig.16 1 is a schematic perspective view of a second brake pad unit 1600, wherein the extended fiber layer of the back plate 1602 comprises woven fibers. It should be noted that the engagement features and the corresponding mating features formed in the friction pad are not shown for simplicity of illustration. It should be noted that in these examples, the extended fiber layer adjacent to the friction pad 1404 is a friction mounted extended fiber layer 600b, 900b comprising engagement features.

[0118] As previously described, the back plate includes an extended reinforcing fiber layer defining a joining feature. In some examples, the extended reinforcing fibers in the extended reinforcing fiber layer including the joining feature are continuous between the molded joining feature and the rest of the friction material mounting surface. In other words, when the joining feature is molded on the friction material mounting surface, its extended reinforcing fibers are not cut by the molding process, and the extended fibers are only bent as needed to be molded as a part of the joining feature that forms a part of them. For example, the extended fibers remain continuous and uninterrupted between the first and / or third portions defining the molded joining feature and the second portion without the joining feature.

[0119] Fig.17 FIG. 4 is a schematic perspective view of a third backplane 400 according to an example. Fig.17 In the embodiment of the present invention, for example, the extension fibers 1702 extend in a continuous (uninterrupted) manner between the engagement feature and the remaining area of ​​the friction material mounting surface 210.

[0120] Preferably, maintaining continuous extended fibers in the friction material mounting surface provides good structural strength. For example, fiber interruption during the molding process does not affect the structural strength of the backing plate. This is an advantage of the joint features produced by the molding method compared to processes such as scraping.

[0121] Please note that all documents and materials filed concurrently or previously with this application and disclosed to the public for inspection with this specification are incorporated herein by reference.

[0122] All features disclosed in this specification (including the accompanying claims, abstract and drawings) and / or all steps of any disclosed method or process may be combined in any manner, except for combinations of at least some of the features and / or steps that are mutually exclusive.

[0123] Each feature disclosed in this specification (including the accompanying claims, abstract and drawings) can be replaced by other alternative features that achieve the same, equivalent or similar purpose, unless otherwise explicitly stated. Therefore, unless otherwise explicitly stated, each feature disclosed is only an example in a series of equivalent or similar features.

[0124] The present invention is not limited to the specific details of the foregoing embodiments. The protection scope of the present invention extends to any novel feature or novel combination of features disclosed in this specification (including any attached claims, abstract and drawings), or any novel step or novel combination of any method steps disclosed.

Claims

1. A method for manufacturing a back plate, the back plate being used to carry friction material to form a brake pad unit of a disc brake assembly, the method comprising: forming a backsheet from a composite backsheet precursor such that the backsheet includes a first side and a second side spaced apart from each other along a first axis, Wherein, forming the backplane comprises: molding the composite back plate precursor within a mold such that a first side of the back plate is configured as a brake mounting surface for engaging a back plate mounting structure of the disc brake assembly; and molding the composite back plate precursor within the mold such that the second side is configured as a friction material mounting surface defining a molded engagement feature, wherein: the friction material mounting surface being defined by an extended reinforcing fiber layer extending from a first edge wall location on the backing plate to a second edge wall location on the backing plate, the edge wall being perpendicular to the first axis; a first portion of the friction material mounting surface including the molded engagement feature offset by a first offset amount relative to a backing plate plane in the direction of the first axis, the backing plate plane being perpendicular to the first axis; a second portion of the friction material mounting surface not including the molded engagement feature is offset relative to the backing plate plane by a second offset amount in the direction of the first axis; and The first offset is different from the second offset.

2. The method according to claim 1, characterized in that The molded engagement feature is in the form of: a moulded engagement feature of the first type configured to extend into said friction material in use; or A second type of molded engagement feature is configured to receive the friction material in use.

3. The method according to claim 2, characterized in that: The first type of molded-in engagement features includes protrusions projecting from the friction material mounting surface; and The second type of mold-engagement feature includes a groove that extends into the back plate but not completely therethrough.

4. A method according to any preceding claim, characterised in that: The mold includes a pressing plate; and The press plate includes a press surface including complementary surface features that correspond inversely to the molded engagement features.

5. The method according to claim 4, characterized in that Forming the back plate includes: placing the composite backplane precursor in the mold; placing the mold in a heated press, setting the temperature of the heated press to be high enough to induce flow of the polymer matrix contained in the composite backsheet precursor; and The mold is compacted to: compressing the composite backsheet precursor to cause the polymer matrix to flow; and The press surface of the press plate is pressed into the composite backing plate precursor to mold the engagement features onto the friction material mounting surface.

6. A method according to any preceding claim, comprising: Using a release agent during the molding process to prevent the composite backsheet precursor from adhering to the mold and to assist in releasing the backsheet from the mold; as well as The back sheet is subjected to a soaking treatment process using a solvent to remove a release agent that migrates into the back sheet composite material during the molding process.

7. The method according to claim 6, comprising: The backing sheet is subjected to a heating cycle to remove the solvent.

8. A method according to any preceding claim, comprising: The friction material mounting surface is roughened to increase its roughness.

9. A method according to any preceding claim, comprising: applying an adhesive layer to the friction material mounting surface; as well as The drying process is performed to dry the adhesive layer.

10. The method according to claim 9, characterized in that: The adhesive layer includes a mixture of a nitrile phenolic adhesive and water.

11. A method according to any preceding claim, characterised in that: The mold engagement feature includes a planar surface offset relative to the back plate plane in a direction perpendicular to the back plate plane, wherein the planar surface is parallel to the back plate plane.

12. A method according to any preceding claim, characterised in that: The friction material mounting surface defining the molded engagement feature is a portion of the extended reinforcement fiber layer, and the extended reinforcement fibers of the extended reinforcement fiber layer extend in a continuous manner between the molded engagement feature and the remainder of the friction material mounting surface.

13. A composite backing plate for carrying friction material to form a brake pad unit of a disc brake assembly, the composite backing plate comprising a first side and a second side spaced apart from each other along a first axis, characterized in that: The composite back panel is formed of a composite material containing reinforcing fibers, and the composite material is distributed throughout the composite back panel; The first side defines a brake mounting surface for engaging a back plate mounting structure of the disc brake assembly; The second side is a friction material mounting surface defining a molded engagement feature molded into the friction material mounting surface, wherein: the friction material mounting surface being defined by an extended reinforcing fiber layer extending from a first edge wall location on the backing plate to a second edge wall location on the backing plate, the edge wall being perpendicular to the first axis; a first portion of the friction material mounting surface including the molded engagement feature offset by a first offset amount relative to a backing plate plane in the direction of the first axis, the backing plate plane being perpendicular to the first axis; an area of ​​the friction material mounting surface that does not include the molded engagement feature is offset relative to the backing plate plane by a second offset amount in the direction of the first axis; and The first offset is different from the second offset.

14. The composite back sheet according to claim 13, characterized in that: The molded engagement feature is in the form of: a moulded engagement feature of the first type configured to extend into said friction material in use; or A second type of molded engagement feature is configured to receive the friction material in use.

15. The composite backboard according to claim 14, characterized in that: The first type of engagement feature includes a protrusion protruding from the friction material mounting surface; and The second type of engagement feature includes a groove that extends into the back plate but not completely therethrough.

16. The composite backboard according to claim 14 or 15, characterized in that: The friction material mounting surface defines a plurality of molded engagement features, wherein: At least one of the plurality of molded engagement features is of a first type; and / or At least one of the plurality of molded engagement features is of a second type.

17. The composite back sheet according to any one of claims 13 to 16, characterized in that: The friction material mounting surface defining the molded engagement feature is a portion of the extended reinforcement fiber layer, and the extended reinforcement fibers of the extended reinforcement fiber layer extend in a continuous manner between the molded engagement feature and the remainder of the friction material mounting surface.

18. The composite back sheet according to any one of claims 13 to 17, characterized in that: The friction material mounting surface is covered with an adhesive layer for bonding the friction material to the friction material mounting surface.

19. The composite back sheet according to any one of claims 13 to 18, characterized in that: The mold engagement feature includes a planar surface offset by a first offset relative to the back plate plane in a direction perpendicular to the back plate plane, wherein the planar surface is parallel to the back plate plane.

20. A brake pad unit for a disc brake assembly, the brake pad unit comprising a composite backing plate according to any one of claims 13 to 19, and a friction pad, wherein: The friction pad includes a friction material bonded to the friction material mounting surface; and The friction pad includes a mating feature that inversely corresponds to and engages with the molded engagement feature.

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