A backing plate mould

Abstract

A composite backing plate is producible from a backing plate mould 60 comprising a surface 61, a protrusion 63, 65 extending away from the surface, and an undercut arranged within the protrusion, the

Description

The present invention relates generally to a composite backing plate mould and a method of manufacturing a composite backing plate, and finds particular, although not exclusive, utility in composite backing plates for vehicle brake assemblies. Vehicle brake systems commonly comprise friction pads attached to a surface of a backing plate. Typically, brake backing plates are formed of metal, such as steel. During braking, to prevent the detachment of the friction pad from the backing plate in a direction parallel to the plane in which the surface of the backing plate lies, it is known to form channels and / or spigot holes within the surface of the backing plate. Portions of the friction pad may extend into the channels and / or spigot holes, such that the friction pad may be anchored to the backing plate. However, whilst these channels and / or spigot holes may prevent movement of the friction pad across the surface of the backing plate, they may not prevent movement of the friction pad perpendicularly away from the surface of the backing plate. To restrict movement of the friction pad perpendicularly away from the surface of the backing plate, it is known to use adhesives to attach the friction pad to the backing plate. However, adhesives may degrade when subjected to temperatures at or above 800 degrees Celsius. Relatively heavy or prolonged braking may produce temperatures at or above 800 degrees Celsius, and so detachment of the friction pad from the backing plate may occur during such braking. As such, an alternative form of attachment includes cutting hooked burrs into the surface of the metal backing plate, which may, in use, be embedded within the friction pad, thereby preventing movement of the friction pad away from the backing plate, as well as in a direction parallel to the extension of the hooked burrs. Relative movement in the opposite parallel direction relative to the extension of the hooked burrs may not be prevented. It is also desirable to reduce the weight of a backing plate, for example, by forming a backing plate from a composite material, such as a polymeric composite, instead of metal. Restricting the relative movement between a friction pad and a composite backing plate is still necessary. However, cutting hooked burrs into the surface of a composite is typically not possible. This is because, due to the relatively brittle nature of composite materials, cutting into the surface will likely chip it or detrimentally affect the backing plate’s structural integrity, rather than form hooked burrs. It is therefore desirable to have a composite backing plate capable of restricting movement of a friction pad relative to the composite backing plate in directions both parallel and perpendicular to the surface of the composite backing plate. In a first aspect, the present invention provides a backing plate mould for forming a composite backing plate for use in a brake assembly wherein a composite backing plate formed using the backing plate mould is arranged to retain a friction pad thereon, wherein: the backing plate mould comprises a surface, a protrusion extending away from the surface, and an undercut arranged within the protrusion, the protrusion and undercut configured to form, in use, a composite backing plate including a corresponding void, and undercut, and / or the backing plate mould comprises a surface with a cavity, and an undercut arranged within the cavity, the cavity and undercut configured to form, in use, a composite backing plate including a corresponding projection, and undercut, wherein the backing plate mould is comprised of a resilient material configured, in use, to remain substantially rigid as a precursor cures within the backing plate mould, and to elastically deform to allow the composite backing plate, formed using the backing plate mould, to be removed from the backing plate mould. When the backing plate mould is used to form a composite backing plate, the composite backing plate will include a surface comprising a void and undercut, and / or a projection and undercut. Then, when a friction pad forming compound is introduced to the surface of the composite backing plate, and then cured, a friction pad is formed. If the composite backing plate comprises a void and undercut, then a portion of the friction pad will fill the void and undercut of the composite backing plate, forming a friction pad which is “locked” to the composite backing plate. It will be appreciated that the protrusion and undercut of the friction pad may have substantially the same dimensions as the dimensions of the protrusion and undercut of the backing plate mould. Furthermore, if the composite backing plate comprises a projection and undercut, then another portion of the friction pad may surround this protrusion and fill the undercut, thereby forming a friction pad which is “locked” to the composite backing plate. It will be appreciated that the cavity and undercut of the friction pad may have substantially the same dimensions as the dimensions of the cavity and undercut of the backing plate mould. It is to be understood that the friction pad forming compound may be a granular or fluid material at the time of application to the composite backing plate, becoming rigid and inflexible on curing. In this way, a portion of the composite backing plate may be located in the undercut of the friction pad, and a portion of the friction pad may be located in an undercut of the composite backing plate, such that the two portions may be interlocked, to thereby prevent movement of the friction pad perpendicularly away from the composite backing plate surface, as well as in a direction parallel to the plane in which the backing plate surface lies. In other words, the two undercuts may correspond to one another in shape and location. The backing plate mould will form a feature in the composite backing plate configured to restrict the movement of the friction pad in directions both parallel and perpendicular to the surface of the composite backing plate, without the need for adhesives, or processes that risk chipping or otherwise damaging the composite backing plate. By providing a backing plate mould comprising a resilient material configured to elastically deform, the backing plate mould may be arranged to form the void and undercut, and / or the protrusion and undercut, in the composite backing plate formed using the mould, yet still be releasable from the subsequently cured, relatively rigid, composite backing plate. Moreover, the backing plate mould may be releasable from the relatively rigid composite backing plate such that it may be reusable. If the backing plate mould was not resiliently deformable then the backing plate mould would have to be broken to release the backing plate due to the interlocked undercuts. The backing plate mould may provide a composite backing plate with means for retaining a friction pad thereon. The backing plate mould may be a polymer composite backing plate mould, meaning that the mould may be arranged to form a backing plate comprising a polymer composite. The polymer composite may comprise a composite matrix including at least one polymer and at least one reinforcement. The surface of the backing plate mould may be a portion of the exterior of the backing plate mould. For example, the surface of the backing plate mould may be the top surface of the backing plate mould. Alternatively, the surface of the backing plate mould may be inset or sunk into the backing plate mould body. The protrusion may comprise a proximal portion adjacent to the surface of the backing plate mould, and a distal portion spaced away from the surface of the backing plate mould. The protrusion may comprise an overhang, and the undercut may be located between the overhang and the surface of the backing plate mould. In this way, the undercut may be located within the proximal portion of the protrusion. The protrusion may comprise an overhang, and the undercut may be located between the overhang and a portion of the protrusion. In this way, the undercut may be located between the proximal portion and distal portion of the protrusion, and / or within a hole or indentation within the end of the distal portion. The overhang of the protrusion may comprise an overhang surface, wherein the overhang surface may be the surface of the overhang arranged to face the surface of the backing plate mould and / or the portion of the protrusion. In this way, the undercut may be the region between the overhang surface and the surface of the backing plate mould, or the region between the overhang surface and the portion of the protrusion. The cavity may comprise an overhang, and the undercut may be located between the overhang and the base of the cavity. The overhang of the cavity may comprise an overhang surface, wherein the overhang surface may be arranged to face the base of the cavity. In this way, the undercut may be the region between the overhang surface and the base of the cavity. The overhang surface of either the protrusion or cavity may comprise a planar portion, and the plane in which the planar portion lies may form an acute angle with the plane in which the surface of the composite backing plate lies. The angle may be between 1 degree and 89 degrees. Preferably, the angle may be 80 degrees. Alternatively, the overhang surface may be arranged to be curved, or stepped, or L-shape. An L-shape overhang surface may comprise a first portion of the overhang surface lying in a plane extending approximately perpendicularly to the plane in which the surface of the backing plate mould lies, and a second portion of the overhang surface lying in a plane extending approximately parallel to the plane in which the surface of the backing plate mould lies. The protrusion and / or cavity may comprise a plurality of undercuts. In this way, the backing plate mould may be arranged to form undercuts at various locations on the protrusion and / or in the cavity. For example, the protrusion and / or cavity may have a substantially T-shape cross-section, in a plane perpendicular to the plane in which the surface of the backing plate mould lies. The protrusion may comprise a wall extending along the surface of the backing plate mould. In this way, the undercut may be arranged to extend along the length of the wall, thereby increasing the volume of the undercut within which a friction pad forming compound may subsequently be introduced. The protrusion may extend up to 15mm from the surface of the backing plate mould. The cavity may have a depth of up to 7mm from the surface of the backing plate mould. The backing plate mould may be arranged to form an approximately rectangular composite backing plate. The backing plate mould may be arranged to form a composite backing plate having a length between 50mm and 300mm, a width between 30mm and 185mm, and a thickness between 3mm and 15mm. The backing plate mould may comprise a plurality of protrusions. An opening of the undercut of one protrusion may be arranged to face an opening of the undercut of another protrusion. One protrusion may have a greater height, relative to die surface of the backing plate mould, than another protrusion. The protrusion may form a channel in the surface of the composite backing plate formed using the backing plate mould, wherein the width of the channel may be wider at its base than at its opening. A portion of a friction pad forming compound may be provided within the channel, such that the compound may fill the void thus forming an “anchor” within the composite backing plate formed using the mould. The anchor may have the shape of the channel, such that it may comprise a first side having the width of the opening of the channel, and a second side the width of the base of the channel. In this way, the anchor may be effectively wedged within the channel, because the second side of the anchor may be wider than the opening of the channel, such that the anchor may be unable to pass through the opening. The backing plate mould may comprise a plurality of cavities. The resilient material may be an elastomer. The elastomer may comprise at least one of: natural rubber, butyl rubber, polysulfide polymer, polychloroprene polymer, and silicone. The resilient material may be sufficiently resilient such that it may deform enough for a user to remove the composite backing plate from the backing plate mould. The backing plate mould may further comprise a collar. The collar may extend around the perimeter of the backing plate mould. The collar may be arranged to form the outer edges of the composite backing plate formed using the backing plate mould. The collar may be integrally formed with the backing plate mould. Alternatively, the collar may be releasably attachable to the backing plate mould. The collar may be comprised of the resilient material, or may be comprised of a material having a greater rigidity than the resilient material. The collar may be comprised of metal. For example, the collar may be comprised of steel. The collar may be used to reduce potential deformation of the backing plate mould as it is used to form a composite backing plate. For example, the collar may prevent the backing plate mould from bulging outwards as pressure from a moulding punch is applied to the backing plate mould during the moulding process. In this way, the collar may maintain the structure of the backing plate mould during moulding. The backing plate mould may be locatable within a sheet having a plurality of mould cut-outs, wherein each cut-out has the shape of the outer perimeter of the backing plate mould. In this way, a plurality of composite backing plates may be manufactured in a single moulding run. Each cut-out may act as a collar for its respective backing plate mould. In this way, the depth of each cut-out may be sufficient to form the outer perimeter of the composite backing plate formed using the backing plate mould. The sheet may have a greater rigidity than the resilient material. The sheet may be comprised of metal, such as steel. A backing plate mould may be locatable within each cut-out. Alternatively, the backing plate mould may comprise a sheet having a plurality of mould sections, wherein the entire sheet, or at least the majority of the sheet, is comprised of the resilient material. In a second aspect, the invention provides a method of manufacturing a composite backing plate for use in a brake assembly wherein a composite backing plate formed using the backing plate mould is arranged to retain a friction pad thereon, the method comprising the steps of: providing the backing plate mould of any preceding claim; providing a precursor; introducing the precursor to the backing plate mould; allowing the precursor to cure within the backing plate mould, thereby forming a composite backing plate comprising a surface, a void extending into the surface, and an undercut, and / or forming a composite backing plate comprising a surface, a protrusion extending from the surface, and an undercut; and elastically deforming the backing plate mould to remove the composite backing plate from the backing plate mould. The precursor may be an at least partially uncured composite material, moulding compound, preform, layup, or resin, such as phenolic resin. In this way, the precursor may not be hardened, and instead may be substantially pliable and mouldable. The method may further comprise the step of punching the precursor into the backing plate mould, before the precursor cures to form a composite backing plate. Elastically deforming the backing plate mould may comprise compressing at least a portion of the protrusion. For example, the entire protrusion may compress, or only the overhang may compress. Elastically deforming the backing plate mould may comprise stretching at least a portion of the protrusion. For example, the entire protrusion may stretch, or only the overhang may stretch. Elastically deforming the backing plate mould may comprise flexing at least a portion of the protrusion. For example, the entire protrusion may flex, or only the overhang may flex. Elastically deforming die backing plate mould may comprise compressing, stretching, or flexing the opening of the cavity. In use, once the composite backing plate has been removed from the mould, a friction pad forming compound may be introduced onto die surface of the composite backing plate. The void, and undercut, may be filled by the friction pad forming compound, and a layer of the compound may be provided on the surface of the composite backing plate. The friction pad forming material may then be cured to form a solid friction pad. As a result, a layer of the friction pad may, in use, be arranged to sit on the surface of the composite backing plate, and a portion of the friction pad may extend from the layer, and into the void and undercut of the composite backing plate. In this way, the portion of the friction pad extending into die undercut may act as a hook to anchor the layer of the friction pad to the composite backing plate, such that relative movement of the friction pad perpendicularly away from, and parallel to, the surface of the composite backing plate is restricted. In a third aspect, there is provided a composite backing plate comprising a surface, a void, and an undercut, and / or a composite backing plate comprising a surface, a cavity, and an undercut arranged within the cavity, the composite backing plate being manufactured by the method of the second aspect. The above and other characteristics, features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. This description is given for the sake of example only, without limiting the scope of the invention. The reference figures quoted below refer to the attached drawings. Figure 1 shows a perspective view of a backing plate mould for manufacturing a composite backing plate; Figure 2 shows a cross-sectional view of the backing plate mould of Figure 1; Figure 3 shows a perspective view of a central portion of the backing plate mould of Figure 1; Figure 4 shows a cross-sectional view of a backing plate moulding apparatus including the backing plate mould of Figures 1 and 3 in a disengaged position; Figure 5 shows a cross-sectional view of a backing plate moulding apparatus including the backing plate mould of Figures 1 and 3 in an engaged position; Figure 6 shows a perspective view of the backing plate mould within a portion of the apparatus of Figures 4 and 5; Figure 7 shows a perspective view of a composite backing plate; Figure 8 shows a cross-sectional view of a section of the composite backing plate of Figure 7; and Figure 9 shows the cross-sectional view of the backing plate of Figure 8 including a friction pad. The present invention will be described with respect to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. Each drawing may not include all of the features of the invention and therefore should not necessarily be considered to be an embodiment of the invention. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention. Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other sequences than described or illustrated herein. Likewise, method steps described or claimed in a particular sequence may be understood to operate in a different sequence. Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that operation is capable in other orientations than described or illustrated herein. It is to be noticed that the term “comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression “a device comprising means A and B” should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B. Reference throughout this specification to “an embodiment” or “an aspect” means that a particular feature, structure or characteristic described in connection with the embodiment or aspect is included in at least one embodiment or aspect of the present invention. Thus, appearances of the phrases “in one embodiment”, “in an embodiment”, or “in an aspect” in various places throughout this specification are not necessarily all referring to the same embodiment or aspect, but may refer to different embodiments or aspects. Furthermore, the particular features, structures or characteristics of any one embodiment or aspect of the invention may be combined in any suitable manner with any other particular feature, structure or characteristic of another embodiment or aspect of the invention, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments or aspects. Similarly, it should be appreciated that in the description various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Moreover, the description of any individual drawing or aspect should not necessarily be considered to be an embodiment of die invention. Rather, as the following claims reflect, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention. Furthermore, while some embodiments described herein include some features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form yet further embodiments, as will be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination. In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practised without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description. In the discussion of the invention, unless stated to the contrary, the disclosure of alternative values for the upper or lower limit of the permitted range of a parameter, coupled with an indication that one of said values is more highly preferred than the other, is to be construed as an implied statement that each intermediate value of said parameter, lying between the more preferred and the less preferred of said alternatives, is itself preferred to said less preferred value and also to each value lying between said less preferred value and said intermediate value. The use of the term “at least one” may mean only one in certain circumstances. The use of the term “any” may mean “all” and / or “each” in certain circumstances. The principles of the invention will now be described by a detailed description of at least one drawing relating to exemplary features. It is clear that other arrangements can be configured according to the knowledge of persons skilled in the art without departing from the underlying concept or technical teaching, the invention being limited only by the terms of the appended claims. Figure 1 is a perspective view of a backing plate mould 60 for manufacturing a composite backing plate. The backing plate mould 60 has an elongate polygonal shape, comprising two opposing curved sides. The curved sides are shown to be the two longer sides of the polygonal shape. The backing plate mould 60 comprises a mould surface 61 facing upwards. The mould surface 61 is shown to be substantially planar. Moulding features are shown to be arranged protruding from the mould surface 61. The moulding features comprise a perimeter wall 63 following the edges of the mould surface 61, and extending perpendicularly away from the plane in which the mould surface 61 lies. The perimeter wall 63 forms a closed loop around the edges of the mould surface 61, so as to retain a composite precursor therein, and act as a boundary therefor. It will be appreciated that the moulding features, in use, may form the desired retentive features in the moulded composite backing plate. An internal wall 65 is located on the mould surface 61, and extends along a curved line equidistant between the two longer sides of the substantially rectangular shape of the backing plate mould 60. The internal wall 65 extends only partially along the length of the mould surface 61, such that a space is provided between the perimeter wall 63, and each respective end of the internal wall 65. The width of the internal wall 65 tapers towards each end, such that the internal wall 65 has a greater width in a central portion, than at either end. A gap is also shown in the internal wall 65, the gap being located at the apex of the curved line along which the internal wall 65 extends, and extending completely through the internal wall 65 in a direction perpendicular to the curved line along which the internal wall 65 extends. The perimeter wall 63 has a greater height than the internal wall 65, relative to the mould surface 61. The mould surface 61, the perimeter wall 63, and the internal wall 65 may be formed of a resilient material, and together may form a keying portion of the backing plate mould 60. The backing plate mould 60 is also shown to include an insert collar 40. The insert collar 40 is shown to be a frame arranged around the keying portion. In particular, the insert collar mould is shown to be adjacent to the outer edges of the perimeter wall 63. The insert collar 40 comprises a hollow inner portion, an open top, and an open base (Figure 3). An upper surface of the insert collar 40 is shown to lie in a plane lower than the plane in which the distal end of the perimeter wall 63 lies, but above the plane in which the mould surface 61 lies. In use, it is intended that the upper surface of the insert collar 40 will form the outer edges of the moulded composite backing plate. The insert collar 40 may comprise a relatively rigid material, such as metal. In this way, the insert collar 40 may maintain the structure of the keying portion of the mould during the moulding process. Figure 2 is a cross-sectional view of the backing plate mould 60 of Figure 1, in a plane perpendicular to the plane in which the mould surface lies (and as shown by plane ‘A’ in Figure 1). A mould base 67 is shown to be attached to the bottom of the substantially curved rectangular block. The mould base 67 is shown to comprise a plate lying in a plane parallel to the mould surface 61. In use, the edges of the mould base 67 may be clamped within a moulding apparatus to prevent relative movement of the backing plate mould 60. Two voids 99 are located within the top of the mould. These voids 99 are defined by the mould surface 61 at their base, and by the walls 63 and 65 at their sides. They are open at the top. The sides of the walls 63 and 65 are seen to extend away from the base 61 at acute angles such that they form overhang surfaces 69, thereby forming undercuts 64 located between the overhang surfaces 69 and the mould surface 61. The overhang surfaces 69 are shown to be planar, and are inclined relative to the mould surface 61 such that the plane in which each overhang surface 69 lies forms an acute angle with the plane in which the mould surface 61 lies. The angle between the plane in which each overhang surface 69 lies and the plane in which the mould surface 61 lies is approximately 80 degrees. However, it will be appreciated that any acute angle may be used, that is, any angle between 1 and 89 degrees. It will be appreciated that in relation to the top surface, the voids 99 are cavities within the top surface, and the undercuts 64 are within the cavities. Figure 3 is a perspective view of a central portion of the internal wall 65 of the backing plate mould 60, in a direction substantially parallel to the direction in which the internal wall 65 extends. The undercuts 64 are shown on the lefthand side, and righthand side, of the internal wall 65, and formed by the overhang surfaces 69 hanging over the mould surface 61. Figure 4 is a cross-sectional view of a backing plate moulding apparatus 10 including the backing plate mould 60 of Figures 1 to 3, taken in the same cross-sectional plane as in Figure 2. A mould collar 20 is shown to surround the apparatus. The mould collar 20 may be a frame comprising a hollow inner portion, an open top, and an open base. It will be appreciated that the hollow inner portion of the mould collar 20 may be configured to form the shape of the outer perimeter of the composite backing plate to be moulded. In this case, the shape of the hollow internal portion may be substantially rectangular. A base flange 25 is shown at the base of the mould collar 20, extending partially into the hollow inner portion of the mould collar 20. The mould collar 20 may comprise a relatively rigid material, such as metal. Also shown is a base plate 30, located at the base of the mould collar 20 and seated on the base flange 25. The base plate 30 has a substantially planar upper surface 35. The insert collar 40 of the backing plate mould 60 is shown to be located within a lower section of the hollow inner portion of the mould collar 20, and seated on the planar upper surface 35 of the base plate 30. A top flange 45 is shown at the top of the insert collar 40, extending partially into the hollow inner portion of the insert collar 40. A punch 50 is shown partially within an upper section of the hollow inner portion of the mould collar 20, with die majority of the punch 50 shown to be located above the mould collar 20. It will be appreciated that the peripheral shape of the punch 50 is intended to match the inner shape of the mould collar 20. The outer walls of the punch 50 are shown to be flush with the inner walls of the mould collar 20. The backing plate mould 60 is shown to be located widain the hollow inner portion of the insert collar 40, and seated on the planar upper surface 35 of the base plate 30. The edges of the mould base 67 of the backing plate mould 60 are shown to be located between die top flange 45 of the insert collar 40, and the planar upper surface 35 of the base plate 30. In this way, the backing plate mould 60 may be clamped in position with the backing plate moulding apparatus 10, in use. Also shown in Figure 4 is a composite backing plate precursor 70, which is shown to be located within the hollow inner portion of the mould collar 20, and between the backing plate mould 60 and the punch 50. The composite backing plate precursor 70 may be an at least partially uncured composite material, moulding compound, preform, layup, or resin, such as phenolic resin. In this way, the composite backing plate precursor 70 may not be hardened, and instead may be substantially pliable and mouldable. Fibres, or other constituents of composite materials may be included within the composite backing plate precursor 70. The moulding apparatus of Figure 4 is shown in a disengaged configuration, wherein the punch 50 is spaced away from the composite backing plate precursor 70. Figure 5 shows the moulding apparatus 10 of Figure 4 in an engaged position. In the engaged position, the punch 50 is shown to be forced down the hollow inner portion of the mould collar 20 towards the backing plate mould 60, such that the composite backing plate precursor 70 is compressed between the punch 50, and the backing plate mould 60 and insert collar 40. Lower portions of the composite backing plate precursor 70 are shown to enclose the perimeter wall 63 and internal wall 65, and fill the undercuts 64, of the backing plate mould 60. It will be appreciated that once the composite backing plate precursor 70 has cured, corresponding voids, and undercuts, will be formed within the composite backing plate as a result. In particular, each void is shown to have an internal shape defined by the perimeter wall 63 or the internal wall 65 of the backing plate mould 60. Once the composite backing plate precursor 70 has cured to form a composite backing plate, the composite backing plate may be pulled from the backing plate mould 60, such that the perimeter wall 63 and internal wall 65 elastically deform to allow the substantially rigid protrusions to be released from the mould cavities 64. The elastic deformation may comprise the edges of the overhang surfaces 69 momentarily flexing or contracting, before returning to their original position. It is also contemplated that the backing plate mould 60 may comprise a sheet having a plurality of mould sections, such that a plurality of composite backing plates may be manufactured in a single moulding run. Figure 6 is a perspective view of the backing plate mould 60 within the mould collar 20. As will be appreciated, the inner surfaces of the mould collar 40 may define the shape of the outer perimeter of a composite backing plate formed using the backing plate moulding apparatus 10, and a face of the composite backing plate for receiving a friction pad may be formed by the upper surface of the insert collar 40, the perimeter wall 63, the internal wall 65, and the mould surface 61. A composite backing plate precursor may be introduced, for example poured or placed, from above into the inner portion of the mould collar 40, such that the mould surface 61, perimeter wall 63, internal wall 65, and upper surface of the insert collar 40 may be completely covered. The mould collar 20 may be removable from the backing plate mould 60 such that the backing plate formed using the backing plate mould may be released from the mould 60. Figure 7 is a perspective view of a composite backing plate 100. The composite backing plate may comprise a cured composite resin, such as phenolic resin. The composite backing plate 100 may be formed using the backing plate moulding apparatus 10 described above. The composite backing plate 100 is shown to be planar. The composite backing plate 100 is shown to have a polygonal shape comprising two opposing straight sides, and two opposing curved sides. In this way, the composite backing plate 100 may be readily received within a vehicle brake calliper. A backing plate surface 110 is shown on an upper face of the composite backing plate 100. A first protrusion 120 is shown to extend perpendicularly away from the backing plate surface 110. The protrusion 120 has a crosssection, in a plane parallel to the plane in which the composite backing plate 100 lies, having a figure-of-eight shape. A second protrusion 130 is shown to extend around the edge of the composite backing plate 100, perpendicularly away from the backing plate surface 110. In this way, the second protrusion 130 resembles a parapet surrounding, but spaced away from, the first protrusion 120. The first protrusion 120 extends further away from the backing plate surface than the second protrusion 130. Six bridge portions 140 extend across the backing plate surface 110 between the first protrusion 120 and the second protrusion 130. The bridge portions 140 extend the same distance away from the backing plate surface 110 as the second protrusion 130. Three bridge portions 140 are shown to be spaced equidistantly along one longer curved side of the approximately rectangular shape of the composite backing plate 100, and one bridge portion is shown to be spaced centrally along each of the remaining sides of the approximately rectangular shape of the composite backing plate 100. Voids 150 are shown located between adjacent portions of the first protrusion 120, and between adjacent portions of the first and second protrusions 120, 130 and the bridge portions 140. Itwill be appreciated that the voids 150 match the moulding features of Figure 1 to 3. The voids 150 may be formed by the overhang walls 69 and the mould surface 61 of the backing plate mould 60 described above. Each of the first protrusion 120, second protrusion 130, and bridges 140, are shown to comprise undercuts 160 located proximate to the backing plate surface 110. Figure 8 is a cross-sectional view of the first protrusion 120 shown in Figure 7, taken in a plane perpendicular to the plane in which the backing plate surface 110 lies. The first protrusion 120 is shown to have overhangs 180 extending into the voids 150 and over the backing plate surface 110, thereby forming the undercuts 160. The overhangs are shown to be angled 80 degrees with respect to the composite backing plate surface 110. However, it will be appreciated that other acute angles are also contemplated, such as 45 degrees. In use, a friction pad forming compound may be introduced into the voids 150, such that the friction material fills the voids 150. The friction pad forming compound may be a liquid, or may be granular. Alternatively, the friction pad forming compound may be a substantially pliable or malleable solid. Upon curing of the friction pad forming compound, a substantially solid and rigid friction pad is formed. The friction pad may be substantially inflexible. Figure 9 shows the cross-sectional view of the backing plate 100 of Figure 8 including a friction pad 200. The friction pad 200 may have been formed by a liquid or granular friction pad forming compound being poured onto the backing plate 100 such that the liquid or granules flowed into the voids 150 and filled the undercuts 160. The friction pad forming compound may then have cured to become substantially solid and rigid. Alternatively, the friction pad 200 may have been formed by a substantially pliable and malleable solid friction pad forming compound being placed onto the backing plate 100, and pressed against the backing plate 100 such that the friction pad forming compound entered the voids 150 and filled the undercuts 160. The friction pad forming compound may then have cured to become substantially solid and rigid. In either of the above methods of forming the friction pad 200, a collar may have been provided around the backing plate 100 to form the outer shape of the friction pad 200. The faction pad 200 includes a planar layer 210, wherein the planar layer 210 is shown to lie above the backing plate 100. Locking portions 220 are shown to extend from the planar 200 into the voids 150 of the backing plate 100. The undercuts 160 of the backing plate 100 are shown to be filled by the locking portions 220. In this way, the locking portions 220 of the friction pad 200 may not be removable from the voids 150 in a direction away from the composite backing plate surface 110, because the locking portions may be unable to deform and move past the overhangs 180. Additionally, the first protrusion 120 of the backing plate 100 may be unable to deform and move past the locking portions 220.

Claims

1. A backing plate mould for forming a composite backing plate for use in a brake assembly wherein a composite backing plate formed using the mould is arranged to retain a friction pad thereon, wherein:the mould comprises a surface, a protrusion extending away from the surface, and an undercut arranged within the protrusion, the protrusion and undercut configured to form, in use, a composite backing plate including a corresponding void, and undercut; and / or the mould comprises a surface with a cavity, and an undercut arranged within the cavity, the cavity and undercut configured to form, in use, a composite backing plate including a corresponding protrusion, and undercut,,whereinthe mould is comprised of a resilient material configured, in use, to remain substantially rigid as a precursor cures within the mould, and to elastically deform to allow the composite backing plate, formed using the mould, to be removed from the mould.

2. The backing plate mould of claim 1, wherein the backing plate mould comprises the protrusion, the protrusion comprises an overhang, and the undercut is located between the overhang and the surface of the backing plate mould, or between the overhang and a portion of the protrusion.

3. The backing plate mould of claim 1, wherein the backing plate mould comprises the cavity, the cavity comprises an overhang, and the undercut is located between the overhang and the base of the cavity.

4. The backing plate mould of claim 1, wherein the backing plate mould comprises CO X J X Xthe protrusion, and the protrusion comprises a plurality of undercuts.

5. The backing plate mould of claim 1, wherein the backing plate mould comprises the protrusion, and the protrusion comprises a wall extending along the surface of the backing plate mould.

6. The backing plate mould of claim 1, wherein the backing plate mould comprises the protrusion, and the protrusion extends up to 15mm from the surface of the backing plate mould.

7. The backing plate mould of any preceding claim, comprising a plurality of protrusions.

8. The backing plate mould of claim 7, wherein an opening of the undercut of one protrusion is arranged to face an opening of the undercut of an adjacent protrusion.

9. The backing plate mould of claim 1, wherein die backing plate mould composes the cavity, and the cavity comprises a plurality of undercuts.

10. The backing plate mould of claim 1, wherein the backing plate mould comprises the cavity, and the cavity has a depth of up to 7mm from the surface of the backing plate mould.

11. The backing plate mould of any preceding claim, comprising a plurality of cavities.

12. The backing plate mould of any preceding claim, wherein the resilient material is an elastomer.

13. The backing plate mould of claim 12, wherein the elastomer is at least one of: O JL -7natural rubber, butyl rubber, polysulfide polymer, polychloroprene polymer, and silicone.

14. A method of manufacturing a composite backing plate for use in a brake assembly wherein a composite backing plate formed using the backing plate mould is arranged to retain a friction pad thereon, the method comprising the steps of: providing the backing plate mould of any preceding claim;providing a precursor;introducing the precursor to the backing plate mould;allowing the precursor to cure within the backing plate mould, thereby forming a composite backing plate comprising a surface, a void extending into the surface,and an undercut, and / or forming a composite backing plate comprising a surface, a protrusion extending from the surface, and an undercut; andelastically deforming the backing plate mould to remove the composite backing plate from the backing plate mould.

15. The method of claim 14, further comprising the step of punching the composite precursor into the backing plate mould, before the composite precursor sets to form a composite backing plate.21

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