Brake pad set and vehicle brake

Abstract

A brake pad set (22) for disc brakes is shown, comprising an inner brake pad (24) and an outer brake pad (26). Each of the brake pads (22, 24) has a backing plate (28) and a brake lining (30, 32) attached to the backing plate (28), which comes into contact with a brake rotor during operation. The inner brake lining (30) and the outer brake lining (32) differ in size and preferably also in geometric shape in top view, wherein the wear volume of the inner brake pad (24) and the wear volume of the outer brake pad (26) differ by less than 10%. Furthermore, a vehicle brake (10) with such a brake pad set (22) is shown.

Description

[0001] The invention relates to a brake pad set for disc brakes with an inner brake pad and an outer brake pad, each brake pad having a backing plate and a brake lining attached to the backing plate which comes into contact with a brake rotor during operation. The invention further relates to a vehicle brake with a brake caliper, a brake carrier into which a brake rotor projects, an actuator unit, and such a brake pad set.

[0002] Typically, the brake pads of the inner and outer brake shoes are essentially the same size. The outer brake shoe is axially held in place by two contact points on the brake caliper and is supported by these two contact points during braking. The inner brake shoe, on the other hand, is actuated by a brake piston, which usually engages in the center of the brake shoe.

[0003] This results in the central area of ​​the inner brake pad, and especially the inner brake lining, being subjected to significantly higher pressure than the outer areas of the inner brake lining, which are not directly actuated by the brake cylinder. In other words, this leads to a locally increased wear in the area of ​​the brake piston. Consequently, a heavily worn brake lining protrudes towards the brake rotor in the areas adjacent to the contact surface with the brake piston, allowing the outer brake lining areas of the inner brake pad to remain in contact with the brake rotor even when the vehicle brake is released. This creates a residual braking torque. Additionally, the rubbing of the outer brake lining areas against the brake rotor can produce disturbing noises for the vehicle occupants.

[0004] Furthermore, uneven wear of the brake pads and the uneven force distribution caused by applying pressure to a single cylinder prevent completely uniform braking performance across the entire surface. This is particularly problematic with electromechanical brakes, as they have large brake blocks with large brake linings and a relatively small brake piston.

[0005] To achieve a more even distribution of force during braking, force distributors are often used to distribute the force exerted by the brake piston evenly across the brake pad. However, these components are heavy and require additional installation space.

[0006] Accordingly, it is an object of the invention to provide a brake pad set that enables improved force distribution and thus more even wear of the brake linings. Furthermore, it is an object of the invention to provide a vehicle brake that uses such a brake pad set.

[0007] The problem is solved according to the invention by a brake pad set for disc brakes with an inner brake pad and an outer brake pad. Each brake pad has a backing plate and a brake lining attached to the backing plate, which comes into contact with a brake rotor during operation. The inner brake lining and the outer brake lining differ in size and preferably also in geometric shape in plan view, wherein the wear volume of the inner brake pad and the wear volume of the outer brake pad differ by less than 10%. In other words, the inner brake lining and the outer brake lining differ in size and have different geometric shapes in plan view, with a nearly constant wear volume. The differences in size and geometric shape in plan view of the brake pads (i.e.,(with regard to the friction surface) lie outside the manufacturing tolerances.

[0008] Furthermore, the object of invention is solved by a vehicle brake, in particular an electromechanical vehicle brake, comprising a brake caliper, a brake carrier into which a brake rotor projects, an actuator unit and the brake pad set described above.

[0009] The different size and shape of the inner and outer brake pads result in optimized force distribution during braking, ensuring that the entire brake pad surface is subjected to pressure. This prevents areas with locally higher wear. Consequently, a force distributor is no longer needed to evenly distribute the force exerted by the brake piston across the brake pad, saving space, weight, and costs. Furthermore, the nearly identical wear volume ensures that the wear on the inner and outer brake pads is minimal, thus conserving resources.

[0010] Since, according to the invention, only the size or shape of the brake pads is changed in the top view, the backing plates can remain unchanged compared to previous backing plates. This has the advantage that a switch to the brake pad sets according to the invention is possible at any time, or that any disc brake can be retrofitted with the brake pad sets according to the invention.

[0011] Accordingly, in the brake pad set according to the invention, preferably only the brake linings are adapted; that is, only the size or shape of the brake linings is changed in a top view, so that the backing plates remain unchanged and can still be used in the vehicle brakes already installed. Thus, the optimized brake pad set can be used without problems in vehicle brakes already installed without incurring higher costs for a vehicle owner or a vehicle dealer, since only the brake pad set and not the entire vehicle brake needs to be replaced.

[0012] According to a preferred embodiment, the brake lining of the inner brake pad is square or circular in plan view. Additionally or alternatively, the brake lining of the outer brake pad can have an arcuate or rectangular shape in plan view. The idea behind this is to adapt the shape of the brake lining in plan view to the shape of the force-applying elements. The optimal shape corresponds to the shape of the brake cylinder and the shape of the contact projections for the inner and outer brake linings, respectively. The brake cylinder is usually round, so the optimal shape for the inner brake lining is circular. However, a square inner brake lining is also more similar to the shape of the brake cylinder than an elongated rectangle, which is not directly subjected to force by the brake cylinder on its outer edges.Since the outer brake pad is acted upon by two contact projections, it is preferably rectangular or arc-shaped so that both contact projections have sufficient space to exert force on the brake block or brake pad.

[0013] Preferably, the brake lining of the outer brake pad has a larger surface area in plan view than the brake lining of the inner brake pad. In particular, the outer brake pad has a brake lining with a surface area at least 10% larger, preferably between 20% and 300% larger. Because the inner brake lining is subjected to braking force at only one point, it can be smaller compared to the outer brake lining, which is supported at two points by the contact projections. To ensure a uniform force distribution, the outer brake lining must therefore be larger than the inner brake lining.

[0014] Since the wear volume of the inner and outer brake pads should differ by less than 10%, the inner brake pad can be thicker than the outer brake pad. If the surface area of ​​the inner brake pad is reduced, its thickness must increase to maintain a relatively constant wear volume. Because of this approximately equal wear volume, the inner and outer brake pads wear evenly, meaning they need to be replaced at roughly the same time. Therefore, maintaining a similar wear volume prevents material waste, as the inner and outer brake pads experience comparable wear.

[0015] Since, in order to achieve a mechanical connection between the backing plate and the friction lining, the brake lining may protrude into a recess in the backing plate or the backing plate may have small projections around which there is friction material, the focus is not solely on the friction lining volume, but on its predetermined wear volume, which extends, for example, to a first contact point of the backing plate with the brake rotor and is based on a new brake lining.

[0016] According to the invention, the thickness of the friction lining is understood to be the dimension of the brake lining starting from the backing plate in the axial direction.

[0017] According to another embodiment, the backing plate of the inner brake pad is thicker than the backing plate of the outer brake pad. Alternatively, the backing plates of the inner and outer brake pads are the same thickness. A thicker backing plate allows the brake lining of the inner brake pad to be pressed more firmly against the brake rotor, thus achieving a consistent or even greater braking effect despite the smaller surface area or size of the brake lining.

[0018] According to a preferred embodiment, the brake lining of the outer brake pad is split into two parts. In other words, the brake lining of the outer brake pad has a recess in the area between the two contact surfaces. This prevents locally increased wear in the center of the outer brake disc, as this area is no longer subjected to contact by both contact surfaces.

[0019] The brake lining of the outer brake pad and the brake lining of the inner brake pad can be made of different materials. The materials for the brake lining of the different brake pads are selected according to their specific requirements. Accordingly, the inner and outer brake linings can differ in their coefficient of friction or material hardness. The outer brake lining typically has a higher coefficient of friction than the inner brake lining, which helps prevent thermal stress cracks in the brake lining.

[0020] As an alternative to the preferred square or circular shape in plan view of the inner brake pad, it can also have a rectangular or arc shape that approximates the shape of a square. The rectangular shape of the inner brake pad preferably has a width-to-height ratio of less than or equal to 3:2, in particular less than or equal to 4:3, and preferably in particular less than or equal to 5:4.

[0021] If the inner brake pad has an arc-shaped form, the width is taken as the width on the radial height of the brake pad in which the central axis of the brake cylinder lies.

[0022] Optionally, the ratio between the height (radial dimension) and width of the inner brake pad's lining can be between 0.6 and 1.1. This ratio indicates that a more square shape is desirable for the inner brake pad. It is important to note that this shape factor is only applicable to the inner brake pad.

[0023] According to one embodiment, the brake lining of the inner brake pad and the brake lining of the outer brake pad are arranged at different radial heights relative to the brake rotor. This ensures that the center of force application to the inner and outer brake pads lies at the same radial height of the brake rotor. This, in turn, ensures optimal braking performance and an optimized braking curve.

[0024] As mentioned previously, the problem is also solved according to the invention by a vehicle brake.

[0025] The actuator unit of this vehicle brake preferably engages the inner brake pad centrally. Additionally, the brake caliper may have contact projections against which the back plate of the outer brake pad rests when the brake is activated. The inner brake pad, on the other hand, may have a rear contact surface with the actuator unit, particularly the brake cylinder, which, viewed axially, lies between the contact surfaces of the outer back plate and the contact projections.

[0026] Further features and advantages will become apparent from the following description, which refers to the following drawings. The drawings show: Fig. 1 a perspective view of a vehicle brake according to the invention; Fig. 2 a perspective view of the outside of the in Fig. 1 vehicle brake shown without a brake caliper and without an actuator unit, so that the brake pad set according to the invention is visible; Fig. 3 a perspective view of the inner side of the in Fig. 1. Vehicle brake shown without a brake caliper and without an actuator unit; Fig. 4 a top view of the in Fig. 1 Vehicle brake shown without brake caliper and actuator unit; Fig. 5 a schematic representation of the inner brake pad; and Fig. 6 a schematic representation of the outer brake pad.

[0027] Fig. Figures 1 to 4 show a vehicle brake 10 with a preferably electromechanical actuator unit 12.

[0028] The vehicle brake 10 is a disc brake and is assigned to a wheel of the vehicle.

[0029] In addition to the actuator unit 12, the vehicle brake also includes a brake housing 14 with a brake caliper 16 and a brake carrier 18, by means of which the vehicle brake 10 is attached to the body of the vehicle.

[0030] In this context, the brake caliper 16 is connected to the brake carrier 18 via linear guides 20 and can be moved axially relative to the brake carrier 18 via these guides and is thus floatingly mounted.

[0031] The brake caliper 16 surrounds a brake rotor (not shown), in particular a brake disc, which can be clamped in an axial direction by a brake pad set 22.

[0032] The brake pad set 22 comprises an inner brake pad 24 and an outer brake pad 26, each brake pad 24, 26 having a back plate 28 and a brake lining 30, 32 attached to the back plate 28, which comes into contact with the brake rotor when the vehicle brake 10 is applied.

[0033] The back plates 28 correspond to the commonly used back plates 28, so that the brake pad set 22 can be installed in any vehicle brakes 10 without having to replace the vehicle brake 10.

[0034] To attach the brake linings 30, 32 to the back plates 28, the brake linings 30, 32 can each have one or more extensions on their side facing the back plate 28, these extensions engaging in recesses in the back plates 28.

[0035] Alternatively, the back plates 28 can also have projections on their sides facing the brake linings 30, 32, which engage in recesses in the brake linings 30, 32.

[0036] The brake pad 24, which is located internally in the axial direction, is mounted on the brake carrier 18 in a manner that allows it to be moved axially.

[0037] The outermost brake pad 26, in the axial direction, rests against at least one contact projection 34, which is an integral part of the brake caliper 16. Typically, the outermost brake pad 26 rests against two laterally projecting contact projections 34, as shown in Fig. 1 shown.

[0038] For lateral storage and to provide axial displacement of the brake blocks, the brake carrier 18 has a U-shaped receptacle for each brake block and a recess on the two side walls of the U, into which a laterally projecting finger provided on the back plate protrudes.

[0039] The brake pad 24, which lies inside along a rotation axis of the actuator unit 12, which defines the axial direction, is actively subjected to a clamping force by the actuator unit 12, in particular by a brake cylinder, when the vehicle brake 10 is activated.

[0040] The axis of rotation of the actuator unit 12 preferably also corresponds to the cylinder axis of the brake housing 14 and the axis of rotation of the brake rotor.

[0041] The axially displaceable brake caliper 16 ensures that the outer brake pad 26 is also subjected to the clamping force. The clamping force is distributed essentially equally between the inner brake pad 24 and the outer brake pad 26. Thus, a frictional connection between both brake pads 24 and 26 of the brake pad set 22 and the brake rotor is ensured by the applied clamping force, which is used to decelerate or lock the vehicle.

[0042] In Fig. Figure 5 shows that the actuator unit 12, in particular the brake cylinder, engages the inner brake pad 24 in the middle.

[0043] In contrast, it shows Fig. 1 the attachment extensions 34, on which the back plate 28 of the outer brake block 26 is supported.

[0044] In comparison of the Fig. 5 and Fig. Figure 6 shows that the rear contact surface 36 of the inner brake pad 24 with the actuator unit 12 lies in the axial direction between the rear contact surfaces 36 of the back plate 28 of the outer brake pad 26 with the contact extensions 34.

[0045] To ensure uniform force application across the respective brake pads 30, 32, the inner brake pad 30 and the outer brake pad 32 differ in size and preferably also in their geometric shape in top view.

[0046] This means that the inner brake pad 24, for example, has a square or circular brake lining 30, while the outer brake pad 26 has an arc-shaped or rectangular brake lining 32.

[0047] Ideally, the size and / or geometric shape in top view of the brake pads 30, 32 are chosen such that the rear contact surfaces 36 do not extend beyond the respective brake pad 30,32.

[0048] However, the brake pads 30, 32 should not be significantly larger than the rear contact surface 36, so that uneven force application to the respective brake pads 30, 32 can be avoided.

[0049] Accordingly, the area of ​​the brake lining 30 of the inner brake pad 24 is preferably smaller than the area of ​​the brake lining 32 of the outer brake pad 26 in top view, since the rear contact surface 36 of the inner brake pad 24 is limited to the actuator unit 12, in particular the brake cylinder. As already mentioned above, the rear contact surface 36 of the outer brake pad 26, on the other hand, corresponds to the two contact projections 34.

[0050] By using an internal brake pad 30 with a smaller surface area in top view, potentially higher wear and thus residual braking torque and resulting disturbing noises are avoided.

[0051] The brake pad 30 of the inner brake block 24 has a smaller, in particular a surface area that is at least 10% smaller, than the brake pad 32 of the outer brake block 26.

[0052] Ideally, the area of ​​the inner brake pad 30 is between 20 and 300% smaller than the area of ​​the outer brake pad 32. In other words, the area of ​​the outer brake pad 32 is at least 10%, preferably between 20 and 300%, larger than the area of ​​the inner brake pad 30. Thus, the difference between the inner brake pad 30 and the outer brake pad 32 is outside the manufacturing tolerance.

[0053] To ensure continued even wear of the two brake pads 30,32, the wear volume of the inner brake pad 24 and the wear volume of the outer brake pad 26 differ by less than 10%.

[0054] To ensure that the wear volume of the inner brake pad 30 does not differ too much from that of the outer brake pad 32, the brake pad 30 of the inner brake shoe 24 has a greater thickness than the brake pad 32 of the outer brake shoe 26. That is, the smaller the surface area of ​​the brake pad 30, the greater its thickness.

[0055] Since the wear volumes of the inner brake pad 24 and the outer brake pad 26 hardly differ, the entire brake pad set 22 can be replaced without any waste of material.

[0056] Additionally, the back plate 28 of the inner brake pad 24 can also have a greater thickness than the back plate 28 of the outer brake pad 26. Alternatively, the two back plates 28 of the brake pad set 22 are the same thickness.

[0057] In principle, the brake pad 30, 32 can be pressed more firmly against the brake rotor by using a thicker backing plate 28. Thus, a thicker backing plate 28 allows for a more even braking force to be applied. Since the inner brake pad 30 has a smaller surface area than the outer brake pad 32, it can therefore be advantageous if the backing plate 28 of the inner brake pad 24 is somewhat thicker.

[0058] To better adapt to the rear contact surface 36 of the contact projections 34 on the outer brake pad 26, the brake lining 32 of the outer brake pad 26 can be divided into two parts. The gap between the two parts of the brake lining 32 lies at the level of the space between the two contact projections 34 (see Fig. 6).

[0059] The two brake pads 30 and 32 can differ not only in size and geometric shape when viewed from above, but also in their material. That is, the inner brake pad 30 can be made of a different material than the outer brake pad 32. The difference between the materials lies in their coefficient of friction.

[0060] For example, a material with a higher coefficient of friction and a higher tendency to wear can be chosen for the outer brake pad 32 in order to meet the corresponding requirements for the brake pad 32.

[0061] Since the size and shape of the brake pads 30, 32 differ, the brake pads 30, 32 also lie at different radial heights in relation to the brake rotor.

[0062] As an alternative to the preferred square or circular shape in plan view of the inner brake pad 30, it can also have a rectangular or arc shape that approximates the shape of a square. The rectangular shape of the inner brake pad 30 preferably has a width b to height h ratio of ≤ 3:2, in particular ≤ 4:3, and preferably ≤ 5:4. If the inner brake pad 30 has an arc shape, the width is taken as the width at the radial height of the inner brake pad 30 on which the central axis A of the brake cylinder lies (see Figure 1). Fig. 5), which in an electromechanical brake also forms the central axis of the driven spindle.

[0063] For the brake pad 30 of the inner brake shoe 24, for example, the ratio between the height h and the width b of the inner brake pad 30 should be between 0.6 and 1.1.

[0064] The exact dimensions: It follows that the height of the inner brake pad 30 should at least not be significantly smaller than the width of the inner brake pad 30, so that the inner brake pad 30 has a more square than rectangular shape in view of the friction surface.

Claims

[1] Brake pad set (22) for disc brakes with an inner brake pad (24) and an outer brake pad (26), wherein each brake pad (24, 26) has a backing plate (28) and a brake lining (30, 32) attached to the backing plate (28) which comes into contact with a brake rotor during operation, characterized by , that the inner brake pad (30) and the outer brake pad (32) differ in their size and preferably also in their geometric shape in top view, wherein the wear volume of the inner brake pad (24) and the wear volume of the outer brake pad (26) differ by less than 10%. [2] Brake pad set (22) according to claim 1, characterized by , that the brake lining (30) of the inner brake block (24) is square or circular in plan view and / or the brake lining (32) of the outer brake block (26) has an arc shape or a rectangular shape. [3] Brake pad set (22) according to claim 1 or 2, characterized by , that the brake lining (32) of the outer brake pad (26) has a larger area in plan view than the brake lining (30) of the inner brake pad (24), in particular an area that is at least 10% larger, and further in particular an area that is between 20 and 300% larger. [4] Brake pad set (22) according to claim 3, characterized by , that the brake lining (30) of the inner brake pad (24) has a greater thickness than the brake lining (32) of the outer brake pad (26). [5] Brake pad set (22) according to any one of the preceding claims, characterized by , that the back plate (28) of the inner brake pad (24) has a greater thickness than the back plate (28) of the outer brake pad (26) or is the same thickness. [6] Brake pad set (22) according to one of the preceding claims, characterized by, that the brake lining (32) of the outer brake pad (26) is split into two parts. [7] Brake pad set (22) according to one of the preceding claims, characterized by , that the brake lining (32) of the outer brake pad (26) and the brake lining (30) of the inner brake pad (24) are made of different materials. [8] Brake pad set (22) according to any one of the preceding claims, characterized by , that the ratio between the height (h) and the width (b) of the brake lining (30) of the inner brake block (24) is between 0.6 and 1.

1. [9] Brake pad set (22) according to any one of the preceding claims, characterized by , that the brake lining (30) of the inner brake pad (24) and the brake lining (32) of the outer brake pad (26) are arranged at different radial heights with respect to the brake rotor. [10] Vehicle brake (10), in particular electromechanical vehicle brake (10), comprising a brake caliper (16), a brake carrier (18) into which a brake rotor projects, an actuator unit (12) and a brake pad set (22) according to one of the preceding claims. [11] Vehicle brake (10) according to claim 10, characterized by , that the actuator unit (12) engages centrally on the inner brake pad (24) and that the brake caliper (16) has contact extensions (34) on which the back plate (28) of the outer brake pad (26) is supported with rear contact surfaces when the brake is activated, wherein the inner brake pad (24) has a rear contact surface with the actuator unit (12) which, viewed in the axial direction, lies between the contact surfaces of the outer back plate (28) with the contact extensions (34).

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