Floating Brake Caliper

Abstract

The brake caliper (10) includes a fixed metal support (14) mountable to a motorcycle and two brake pads (12, 13) with associated backing plates (12b, 13b) having at least one side surface (18a, 18b) extending substantially radially relative to the rotational axis of the vehicle wheel in use. The slide block (15) includes two metal end plates (21, 22) locked together by a rigid plastic body (24) interposed between the two end plates. The fixed support (14) has an abutment surface (25) facing one of the side surfaces (18a, 18b) of each backing plate (12b, 13b). The plastic block forms recesses (27) that accommodate the brake pads and allow them to reach a stable abutment position against the bearing surface of the fixed support during braking.

Description

[Technical Field]

[0001] The present invention relates to a floating brake caliper made partly from plastic material, and is particularly applicable to, but not limited to, two-wheeled vehicles such as bicycles. [Background technology]

[0002] A floating brake caliper for a motorcycle typically includes a fixed support portion fixed to the vehicle and a slide block that is slidable relative to the support portion and the brake disc along a direction parallel to the rotational axis of the brake disc. The slide block has an overall C-shape and includes a bridge portion, and both ends of the bridge portion are connected to side portions that extend laterally relative to the bridge portion. This shape allows the slide block to straddle the brake disc with the side portions facing the braking surface of the brake disc. One surface of the side portion facing the brake disc is conventionally configured to house a cylinder or piston. Brake pads, located between the piston and the braking surface of the brake disc, are urged toward the brake disc by the piston during braking, generating braking force. The load generated during braking is mainly transmitted from the pads to the slide block.

[0003] As is well known, the sliding blocks of motorcycle brake calipers are made of metal materials, typically aluminum or steel, to withstand the loads experienced during braking and to transmit these loads to the vehicle structure, and the manufacturing costs of these sliding blocks are high due to both the selection of materials and the manufacturing process.

[0004] US Patent Application Publication No. 2022 / 0381304 discloses a brake caliper comprising two brake pads, a fixed support mountable to a vehicle, and a block axially movable relative to the fixed support, wherein the brake pads are axially movable and positionable against two opposing braking surfaces of a brake disc, and each brake pad has a backing plate with at least one side extending substantially radially relative to the axis of rotation of the vehicle wheel in use.

[0005] Conventionally, a slide block has a substantially C-shape overall, and is made of a single, integral metal body with two side wings connected by a connecting portion, and between the side wings and the connecting portion there is an open space that allows the outer periphery of the rotating brake disc to pass through, and in the area defined axially between the side wings there is an open space for accommodating two brake pads. Summary of the Invention

[0006] A primary object of the present invention is to provide a lightweight brake caliper. A further object of the present invention is to provide an economical brake caliper. Another scope of the present invention is to provide a brake caliper that can efficiently transfer heat loads to the environment and braking loads to the vehicle structure.

[0007] These and other objects and advantages, which will be better understood hereinafter, are achieved by a brake caliper having the features set out in independent claim 1. Preferred embodiments of the invention are set out in the dependent claims.

[0008] Briefly, a floating brake caliper for a motorcycle includes one or more pistons, two brake pads each having a backing plate with at least one side extending radially toward the rotational axis of the wheel, a fixed support member fixed to the vehicle and having an abutment surface facing one of the side surfaces of each backing plate, and a slide block axially movable relative to the fixed member and positioned on the brake disc in a bridge-like manner during use. The slide block includes first and second end plates and metal connecting elements for the end plates. The slide block further includes a rigid plastic body interposed and locked between the end plates and having recesses for accommodating the brake pads. The recesses in the rigid plastic body allow the brake pads to achieve a stable stopping position against the abutment surfaces of the fixed support member during braking.

[0009] The characteristics and advantages of the present invention will become apparent from the following description, given by way of non-limiting example, with reference to the accompanying drawings, in which: [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view showing an embodiment of a brake caliper according to the present invention. [Figure 2] FIG. 2 is a perspective view of the brake caliper of FIG. 1 as seen from a different angle. [Figure 3] FIG. 3 is an exploded perspective view of the brake caliper of FIG. [Figure 4] FIG. 4 is an exploded perspective view of some of the components shown in FIG. [Figure 5] FIG. 5 is an exploded perspective view of a block forming part of a brake caliper. [Figure 6] FIG. 6 is a perspective view of the block of FIG. 5 in an assembled state. [Figure 7] FIG. 7 is a perspective view of a fixed support forming part of the brake caliper. [Figure 8]FIG. 8 is a perspective view showing a state in which the radially extending side portions of the brake pads come into contact with the contact surfaces of the fixed support portions of the brake caliper during braking. [Figure 9] FIG. 9 is a perspective view of the abutting state shown in FIG. 8, in which the fixing portion is partially transparent to show some hidden parts. [Figure 10] FIG. 10 is a perspective view of a rigid plastic body forming part of a brake caliper. [Figure 11] FIG. 11 is a perspective view of the rigid body of FIG. 9 from another angle. [Figure 12] FIG. 12 is a vertical cross-sectional view of the brake caliper of FIG. [Figure 13] FIG. 13 is a cross-sectional view of the brake caliper of FIG. [Figure 14] FIG. 14 is a cross-sectional view of an alternative embodiment of a brake caliper according to the present invention. [Figure 15] FIG. 15 is a perspective view of a brake caliper coupled to a vehicle frame and straddling a brake disc. [Figure 16] FIG. 16 is a perspective view of the brake caliper, frame, and brake disc of FIG. 15, viewed from a different angle. DETAILED DESCRIPTION OF THE INVENTION

[0011] Referring initially to Figures 1 to 3, a brake caliper according to an embodiment of the present invention will be described. A brake caliper for a motorcycle is generally indicated at 10. The brake caliper will typically have a generally C-shaped configuration and may be positioned to bridge or straddle a brake disc (shown in Figures 12 and 13) in a known manner.

[0012] The brake caliper 10 defines a transverse axis x (FIGS. 1-3) parallel to the axis of rotation of the brake disc. Throughout this specification and the claims, terms and expressions indicating position, direction, and orientation, such as "axial" and "transversal," are intended to refer to axes that, in the installed state, are parallel to the axis of rotation of the wheel with which the brake caliper is associated. The term "longitudinal" should be understood to refer to a direction perpendicular to the direction defined herein as transverse and parallel to the direction of forward movement of the vehicle. The term "radial," on the other hand, should be understood to refer to a direction that is relative to the axis of rotation of the brake disc and is therefore radial to the transverse axis x and lies in a vertical plane perpendicular to the transverse axis x. The term "tangential" should be interpreted with respect to the rotation of the brake disc.

[0013] The brake caliper 10 comprises at least one piston 11, two brake pads 12, 13, a fixed support 14 and a slide block 15 (FIG. 3) transverse to the fixed support 14.

[0014] The piston 11 is generally cylindrical and has a cylindrical side surface 16 and a longitudinal bottom surface 17 .

[0015] According to one embodiment, the piston 11 is made of a plastic material, for example phenolic resin (PF).

[0016] The brake pads 12, 13 are arranged on either side of the brake disc and are axially movable along a transverse axis x.

[0017] The structural and functional features of floating-type brake calipers are well known and will not be described in detail herein, suffice to say that during braking, pressurized fluid is supplied to a hydraulic chamber within the caliper, which urges one or more pistons laterally relative to a first brake pad toward a first side of the brake disc. When the first brake pad contacts the brake disc, the pressure of the pistons causes a sliding block to move perpendicular to the plane of the brake disc, causing a second brake pad to contact a second side of the brake disc opposite the first side.

[0018] Each brake pad 12, 13 includes a backing plate 12b, 13b, on one side of which a corresponding layer 12a, 13a of friction material is firmly attached, the layer 12a, 13a facing a corresponding one of the two opposing braking surfaces of the brake disc during use. The friction material may typically be a sintered body. To be able to withstand loads during braking, the backing plates 12b, 13b are usually made of a metallic material such as iron or its alloys. As is well known, actuation of the piston 11 brings the friction material 12a, 13a into contact with the braking surface of the brake disc during braking. The brake pads described and illustrated herein may be of conventional design.

[0019] The backing plate 13b has, on the surface opposite to the surface facing the brake disc, an engagement surface 13c (FIG. 3) engageable by the piston 11 to receive the lateral thrust from the piston 11 during braking.

[0020] Additionally, backing plates 12b, 13b of brake pads 12, 13 each have a pair of opposing side surfaces 18a, 18b (FIGS. 3, 8, 9) that lie in two corresponding lateral planes oriented substantially radially toward the axis of rotation of the wheel when mounted on the vehicle. Each side surface 18a, 18b of backing plates 12b, 13b defines a radially extending or elongated side surface having a radial dimension greater than its axial dimension.

[0021] According to one embodiment, the fixed support part 14 has a generally elongated shape in the longitudinal direction (FIG. 2) or tangential direction, taking into account the state of the caliper in use mounted on a vehicle, relative to the direction of rotation of the brake disc. The fixed part 14 can be considered as a spacer or adapter and may be manufactured in different sizes and shapes to fit the caliper and therefore to suit different vehicles.

[0022] The fixed part 14 may have at its ends two holes 19, 20 (Fig. 7) or other means or mounting seats that allow the fixed support part 14 and therefore the brake caliper 10 to be fixed to the vehicle chassis.

[0023] Preferably, the fixed support 14 is made of a metallic material such as aluminum or steel to ensure a strong and stable attachment to the vehicle.

[0024] In the floating brake caliper 10, the slide block 15 can slide relative to the fixed part 14 in an axial direction, i.e., a direction parallel to the transverse axis x.

[0025] The slide block 15 is axially slidable toward the fixed part 14 and is configured to straddle the outer periphery of the rotating brake disc during use (FIGS. 15 and 16).

[0026] As shown in Figure 6, the slide block 15 has a substantially C-shape overall, with two axially spaced side wings 15a, 15b connected by a connecting portion 15c. A space or gap 15d is defined between the side wings 15a, 15b and the connecting portion 15c. The space 15d accommodates the two brake pads 12, 13 between the side wings 15a, 15b and allows the outer periphery of the brake disc to pass between the brake pads during use.

[0027] The side wings 15a, 15b, connecting portion 15c, and gap 15d of slide block 15 are formed by combining several parts, namely, two opposing end plates 21, 22, a connecting element 23, and a plastic body 24 sandwiched between the end plates 21, 22.

[0028] 5 and 6, the slide block 15 comprises two opposing end plates 21, 22, i.e., a first end plate 21 and a second end plate 22, spaced apart from each other in the axial direction and located at opposite axial or lateral ends of the slide block 15. The slide block 15 further comprises an axial or lateral connecting element 23 connecting the two end plates 21, 22 to each other, and a body 24 made of plastic material interposed between the first end plate 21 and the second end plate 22 and firmly locked by the connecting element 23.

[0029] The end plates 21, 22 and the connecting elements 23 are made of metal, advantageously steel.

[0030] The end plates 21, 22 extend in respective geometric planes that are perpendicular to the transverse axis x and are laterally spaced apart. The connecting elements 23 extend axially and rigidly join the end plates 21, 22 to one another. The end plates 21, 22 are axially spaced apart so that they are located on either side of the brake disc in the installed state.

[0031] Advantageously, the connecting elements 23 may be formed as transversely elongated pins or rods which, in addition to performing the structural function of connecting the end plates 21, 22, also serve to mount the brake pads 12, 13. To this end, the backing plates 12b, 13b may have respective through holes 12d, 13d (FIG. 3) into which the connecting pins 23 may be inserted.

[0032] The slide block 15 further comprises a rigid body 24 of plastic material interposed between the first end plate 21 and the second end plate 22 and locked by the connecting element 23 .

[0033] The operation of a floating brake caliper is generally considered to be known, therefore, in the remainder of this specification, only elements relevant to the implementation of the floating brake caliper according to the present invention will be described, and for parts and elements not shown in detail, such as the implementation of hydraulic connections, any solution relating to a floating brake caliper of known design may be referred to.

[0034] The fixed portion 14 of the brake caliper 10 includes at least one abutment surface 25 (FIG. 7) formed to face one (side surface 18a) of the two side surfaces 18a, 18b (FIGS. 8 and 9) of each of the backing plates 12b, 13b.

[0035] The abutment surface 25 and the side surface 18a of each backing plate 12b, 13b may be flat. In an alternative embodiment (not shown), the abutment surface 25 of the fixed support 14 and the side surface 18a of each backing plate 12b, 13b may have corresponding at least partially mating shapes to provide an extended contact surface for more efficiently transferring braking loads. For example, the surfaces 25a, 18a may have corresponding matching curvatures.

[0036] A protrusion 26 (FIG. 8) of the fixed support 14 may present a bearing surface 25 .

[0037] In an alternative embodiment, the fixed portion 14 may be formed as a monoblock having a single abutment surface 25. In an alternative embodiment, the abutment surface 25 may comprise at least two discontinuous and / or parallel surfaces. Although not shown, in another embodiment, the abutment surface 25 may be provided on an element formed separately from the fixed portion 14 and may be rigidly attached thereto by mechanical fasteners such as screws or bolts or by an interlock. In other embodiments, the fixed portion 14 may be formed as a single piece with the bicycle fork.

[0038] The rigid body 24 of plastic material defines a space or gap 15d between the side wings 15a, 15b for accommodating the brake pads and has recesses 27 which, in use, allow the outer periphery of the brake disc to pass between the pads. The recesses 27 are configured to enable the side surface 18a of each backing plate 12b, 13b to reach a stable abutment position against the abutment surface 25 of the fixed support 14 during braking.

[0039] The rigid body 24 is made of plastic and can therefore advantageously be manufactured by injection molding using a material such as polyamide (PA66). In particular, polyamides reinforced with different proportions of glass or carbon fibres, for example 30% or 50% (PA66GF30, PA66GF50) may also be used.

[0040] According to one embodiment, the rigid body 24 may have a generally L-shaped configuration with a top portion 28 (or radially outer portion) and a side portion 29 (FIGS. 7 and 8). The top portion 28 of the rigid body 24 extends substantially axially and may have a curved shape to match the shape of the backing plates 12b, 13b of the brake pads 12, 13.

[0041] Furthermore, the upper portion 28 may be provided as a bridge formation connecting the first end plate 21 and the second end plate 22 on either side of the rigid body 24 .

[0042] The side 29 (FIG. 1) of the rigid body 24 may extend in the longitudinal direction and may have at least two through holes 30, 31 (FIG. 10) spaced apart and facing each other with respect to the transverse axis x. Preferably, the two through holes 30, 31 may be parallel to the transverse axis x.

[0043] 12, the brake caliper 10 may include two pins 32, 33 fixed to and integral with the fixed support 14. The pins 32, 33 may pass through two holes 30, 31 that extend through the side 29 of the rigid body 24, and thus may guide the axial movement of the slide block 15 relative to the fixed support 14 during braking.

[0044] The pins 32, 33 may be oriented horizontally, i.e. substantially parallel to the transverse axis x, and spring elements 32a, 33a may be interposed between the pins 32, 33 and the rigid body 24.

[0045] The rigid body 24 is interposed between the first plate 21 and the second plate 22 and is locked and held together by the connecting element 23 .

[0046] The rigid body 24 has an inner surface 34 facing the piston 11 and brake pads 12, 13 and an outer surface 35 opposite the inner surface 34 (FIGS. 10 and 11). The outer surface 35 may have an outer recess 36, and the inner surface 34 may have an inner cylindrical cavity 37.

[0047] Preferably, the rigid body 24 defines an axial passage 38 extending from the outer surface 35 to the inner surface 34. In particular, the passage 38 connects the outer surface 35 to an inner cylindrical cavity 37.

[0048] Manufacturing the rigid body 24 from plastic by injection molding is particularly advantageous for obtaining a one-piece, low-weight rigid body. Furthermore, molding manufacturing offers advantages in terms of time and processing costs, making the brake caliper more economical. In fact, this technique allows the rigid body 24 to have the outer recess 36, cylindrical cavity 37, and passage 38 formed in a single operation, without the need for subsequent operations or material removal.

[0049] An outer recess 36 on an outer surface 35 of the rigid body 24 may be configured to receive the first plate 21 ( FIG. 3 ). In particular, the outer recess 36 may have a shape that mates with the contour 21 a or edge of the first plate 21 to receive and immobilize the first plate 21 and prevent relative movement of the first plate 21 with respect to the rigid body 24.

[0050] An inner cylindrical cavity 37 disposed on the inner surface 34 of the rigid body 24 may have a cylindrical side wall 39 and a bottom wall 40 (FIG. 10). The inner cylindrical cavity 37 is configured to at least partially accommodate the piston 11 and form a hydraulic chamber 41 for receiving and actuating the piston 11. In particular, the inner cylindrical cavity 37 may have a diameter that substantially corresponds to the diameter of the piston 11.

[0051] A passageway 38 may be provided through the side 29 of the rigid body 24 coaxially with the transverse axis x. The passageway 38 is preferably cylindrical to accommodate at least one hydraulic connector 42 and place a supply channel 43 in fluid communication with a hydraulic chamber 41 (FIG. 13).

[0052] During braking, brake fluid flows from inlet channel 43 into hydraulic chamber 41, expanding hydraulic chamber 41 and actuating floating brake caliper 10. Specifically, during braking, piston 11 is urged axially toward brake pad 13, which approaches the braking surface of the brake disc. As a result of the pressure of the brake fluid in the hydraulic chamber, rigid body 24 and first end plate 21 move axially away from the piston, forcing second end plate 22 and brake pad 12 toward a second surface of the brake disc opposite the first surface.

[0053] The brake pad 10 may further include at least one annular resilient sealing element 44 (FIGS. 12 and 13), typically having a rectangular or square cross-sectional area, capable of providing a sliding contact seal between the cylindrical surface 16 of the piston 11 and the cylindrical wall 39 of the inner cylindrical cavity 37 of the rigid body 24.

[0054] In a preferred embodiment (FIG. 13), the resilient annular sealing element 44 is partially housed in a groove 45 made in the cylindrical surface 16 of the piston 11. In such an embodiment, the resilient annular sealing element 44 acts in sliding contact against the cylindrical wall 39 of the inner cylindrical cavity 37 of the rigid body 24. This embodiment is particularly advantageous when the rigid body 24 is obtained in a molding process, since the cylindrical surface 39 of the inner cylindrical cavity 37 of the rigid body can be made smooth and free of undercuts, without the need for additional machining of the component and using a mold with a simplified geometry.

[0055] The sealing element 44 may be mounted in radial compression between the groove 45 of the piston 11 and the cylindrical wall 39 of the rigid body 24. During braking, the sealing element 44 is elastically deformed in the axial direction due to the relative axial movement of the piston 11 and the rigid body 24 in opposite directions. When braking ceases, the elastic element 44 returns to its undeformed state, urging the piston 11 away from the brake pads 13, which are pushed by the springs 46 away from the braking surface of the brake disc. At the same time, the rigid body 24 and the first plate 21 are moved in an axial direction opposite to that of the piston 11, urging the second plate 22 away from the brake pads 12, which are pushed by the springs 46 away from the braking surface of the brake disc. This action of pushing the brake pads 12, 13 away from the brake disc can be advantageously accentuated by the release action of the spring elements 32a, 33a mounted between the pins 32, 33 and the rigid body 24.

[0056] In an alternative embodiment (FIG. 14), a groove 45 containing an annular resilient sealing element 44 may be formed in the cylindrical wall 39 of the inner cylindrical cavity 37 of the rigid body 24. In such an embodiment, the sealing element may act against the cylindrical surface 16 of the piston 11.

[0057] In one embodiment, the brake caliper 10 may be attached to the frame 51 of the motorcycle (Figures 15 and 16) by a fixed support 14 and may be positioned to straddle the brake disc 50 so that the friction material layers 12a, 13a of the brake pads 12, 13 face each of the two opposing braking surfaces of the brake disc 50.

[0058] As will be appreciated, the abutment surface 25 for the brake pads is advantageously provided by a fixed metallic support rigidly fixed (or integral) to the fork, and not by the caliper body as in conventional non-floating brake calipers, in which the caliper body is stressed only by the hydraulic pressure exerted by the compression of the pads on the disc, and not by the transmission of braking torque to the fork.

[0059] While specific embodiments of the present invention have been disclosed, it should be understood that this disclosure is provided purely for purposes of illustration and not limitation. Various modifications will become apparent to those skilled in the art in light of the above examples. The scope of the present invention is limited only by the appended claims.

Claims

1. A brake caliper (10) for a motorcycle, the brake caliper defining a transverse axis (x); The brake caliper two brake pads (12, 13) axially movable and positionable in use against two opposing brake disc braking surfaces, each brake pad (12, 13) having a backing plate (12b, 13b) with at least one side surface (18a, 18b) that in use extends substantially radially relative to the axis of rotation of the vehicle wheel; a fixed support (14) made of a metallic material and fixable to or integral with the motorcycle, said fixed support (14) comprising at least one abutment surface (25) facing one (18a) of the side surfaces (18a, 18b) of each backing plate (12b, 13b) in use; a slide block (15) axially slidable relative to the fixed support (14), the slide block being configured to be positioned so as to straddle a brake disc in use, the slide block (15) having a substantially C-shape overall with two side wings (15a, 15b) connected by a connecting portion (15c), a space (15d) being defined between the two side wings (15a, 15b) and the connecting portion (15c), the space accommodating the two brake pads (12, 13) between the side wings (15a, 15b) and allowing the outer periphery of the brake disc to pass between the brake pads; Equipped with The slide block (15) a first metal end plate (21) and a second metal end plate (22) arranged in use on either side of said brake disc and constituting a respective one of said axially spaced side wings (15a, 15b); a metallic connection element (23) that firmly connects the first end plate (21) and the second end plate (22); a rigid body (24) made of plastic material, interposed and locked between the first end plate (21) and the second end plate (22), the rigid body (24) forming a recess (27) that provides the space (15d) for accommodating the two brake pads (12, 13); Equipped with The side surface (18a) of each backing plate (12b, 13b) has an abutment position against the abutment surface (25) of the fixed part (14) via the recess (27) of the rigid body (24) during braking.

2. The rigid body (24) an outer surface (35); an inner surface (34) located opposite the outer surface (35) and facing the piston (11); at least one internal cylindrical cavity (37) formed in said inner surface (34) for partially accommodating at least one corresponding piston (11) and defining a hydraulic chamber (41) together with said corresponding piston (11); an axial passage (38) extending between the inner cylindrical cavity (37) and the outer surface (35) for establishing fluid communication between the hydraulic chamber (41) and a hydraulic connector (42) for delivering brake fluid to a brake caliper; 2. The brake caliper (10) of claim 1, comprising:

3. The rigid body (24) an outer surface (35); an inner surface (34) located opposite the outer surface (35) and facing the piston (11); an outer recess (36) formed in the outer surface (35) of the rigid body (24) and configured to receive the first end plate (21); 3. A brake caliper (10) according to claim 1 or 2, comprising:

4. 4. The brake caliper (10) of claim 3, wherein the outer recess (36) of the rigid body (24) has a shape that matches the contour (21 a) of the first end plate (21) so as to receive and lock the first end plate (21) and prevent relative movement with respect to the rigid body (24).

5. 3. A brake caliper (10) according to claim 2, comprising at least one resilient annular sealing element (44) mounted in a groove (45) formed in the cylindrical surface (16) of the piston (11) and acting in sliding contact against the cylindrical wall (39) of the inner cylindrical cavity (37).

6. 2. The brake caliper (10) of claim 1, further comprising at least two axially elongated pins (32, 33) fixed to and integral with the fixed support (14) and configured to guide axial movement of the slide block (15) relative to the fixed support (14).

7. 7. The brake caliper (10) according to any one of claims 1 to 6, wherein the connecting element (23) is an axially elongated pin that connects the first end plate (21) and the second end plate (22).

8. 8. A brake caliper (10) according to any one of the preceding claims, wherein the fixed support (14) is formed as a single piece integral with the fork of the two-wheeled vehicle.

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