Device for thermal insulation on an actuating device for disc brakes

Abstract

Device for thermal insulation on an actuating device of a disc brake, which can be actuated with a pressure medium and has a piston sliding in a cylinder for axially displacing the brake pads against a brake disc, in particular a partial pad disc brake with an insulating body made of a non- or poorly thermally conductive material for insulating the components of the actuating device from a brake pad, characterized in that a metallic brake pad (2) designed as an annular disc is enclosed in an insulating body (5) made of ceramic material which can be inserted into the piston (1) and which is essentially annular in shape, wherein the surface of the insulating body (5) is designed to be convexly rounded towards the piston (1) with respect to its circumferential surface (9), the brake pad (2, 10) is made of stainless steel and zirconium oxide is used as the ceramic material for the insulating body (5, 11).

Description

[0001] The invention relates to a device for thermal insulation on an actuating device for a disc brake which can be acted upon by a pressure medium and has a piston sliding in a cylinder for axially displacing the brake pads against a brake disc, in particular in spot-type disc brakes with an insulating body made of non- / poorly thermally conductive material for insulating the components of the actuating device from a brake pad.

[0002] The heat generated during braking as a result of the conversion of kinetic energy into thermal energy between the brake pad and the brake disc must not impair braking performance. Therefore, thermal stress on the actuating device (piston, cylinder, pressure fluid) must be effectively avoided. Furthermore, with spot-type brake discs, the high stress on the components and, in some cases, the resulting vibrations can cause damage to the components, which can adversely affect braking performance.

[0003] Various attempts at solutions have become known from the state of the art, particularly for preventing temperature stress on the components of a braking system.

[0004] EP 0 042 156 A1, DE 60 2005 001819 T2 and DE 85 33 587 U1 each disclose the subject matter of the preamble of claim 1.

[0005] Furthermore, WO 2004 / 059188 A1 discloses a multi-part actuating device for a spot-type disc brake, in which a heat-insulating member made of plastic or ceramic material is provided between the actuating piston and a metallic brake pad, in which the metallic brake pad is embedded.

[0006] EP 0 042 156 A1 proposes integrating a block of insulating material into the brake piston, to which a disc-shaped cover made of stainless steel is attached as the actual brake pad. Finally, FR 2 495 252 A1 discloses a cup-shaped brake piston with a brake pad carrier attached thereto, in whose cup-shaped cavity a large amount of thermally insulating material is inserted.

[0007] The invention is based on the object of offering a particularly effective thermal insulation for a device as characterized above, while at the same time providing a construction that can withstand the highest loads.

[0008] This object is achieved according to claim 1 in that a metallic brake pad is accommodated in a substantially annular insulating body made of ceramic material which can be inserted into the piston, wherein the surface of the insulating body is convexly rounded towards its annular circumferential surface.

[0009] The brake pad is made of stainless steel.

[0010] Furthermore, zirconium oxide is used as a ceramic material for the insulation body.

[0011] It is particularly useful to make the brake pad circular and to embed it in a circular insulating body that surrounds the brake pad in a ring shape.

[0012] In this solution, the brake pad can be designed with a substantially circular, cup-shaped design. The substantially circular insulating body can be inserted into the cup-shaped recess of the metallic brake pad.

[0013] The brake pad and insulation body should be inserted or fastened into the piston in such a way that heat transfer to the piston and in particular to the pressure medium, etc., can be completely or largely avoided by largely avoiding direct transitions.

[0014] Advantages, features, and details of inventive solutions for thermal insulation on brake pistons emerge from the following description of two alternative embodiments and from the schematic representations in the drawings. The described features and feature combinations, as shown below in the figures of the drawings, and the features and feature combinations described with reference to the drawings can be used not only in the respective specified combination, but also in other combinations or even on their own, without thereby departing from the scope of the invention.

[0015] It shows: Fig. 1 a piston for a disc brake with brake pad and heat insulation body in section; Fig. 2 a pot-shaped brake pad with an insulating body inserted into the receiving pot of the brake pad in a sectional perspective view; Fig. 3 a perspective view of an insulation body with a brake pad inserted therein (alternative design to the illustrations in Fig. 1 or 2) and Fig. 4 a pot-shaped brake pad with an insulating body inserted into the receiving pot of the brake pad according to the design according to Fig. 3 in section in perspective view.

[0016] In Fig. 1, 1 represents a piston for a pressure-medium-actuated disc brake. As will be readily apparent to a person skilled in the art, this piston 1 is axially movable in the direction of the arrow in a cylinder (not shown) under the action of a pressure medium (e.g. hydraulic oil) in order to bring a brake pad 2 into contact with a brake disc (not shown) for braking, for example a vehicle. The brake pad 2 is circular in design and provided with a cup-shaped projection 3, which can be formed integrally with the brake pad 2. An insulating body 5 is inserted into an opening 4 in the cup-shaped projection 3. The brake pad 2 and the insulating body 5 can be fastened in the piston 1 - preferably detachably - by means of a screw 6 or a similar connecting element.

[0017] The piston 1 is arranged in a known manner in a brake piston housing 7. The brake pad 2 has a substantially centrally arranged brake contact surface 8, which has convex, rounded side surfaces extending toward the ring peripheral surface 9.

[0018] Due to this significant rounding of the brake pad 2 in its lateral areas, the heat buildup due to friction is essentially limited to the central area of ​​the brake pad 2, so that in its outer area, hardly any or at most only a small, non-critical heat transfer to the piston 1 can occur. In the central area of ​​the brake pad 2 or the screw 6, heat transfer from the brake pad 2 to the piston 1 is effectively prevented by the insulating body 5.

[0019] If necessary, it is conceivable to provide an additional insulation ring (not shown) surrounding the cup-shaped projection 3 in the area where the brake pad 2 rests to prevent heat transfer in this area.

[0020] Fig. 2 shows a perspective sectional view of the brake pad 2 and the insulation body 5 according to the embodiment according to Fig. 1. As Fig. As can be clearly seen in Figure 2, the ring peripheral surface 9, i.e., the transition area from the brake contact surface 8 to the outer circumference of the brake pad 2, has a distinctly convex, rounded shape. This design prevents, for example, increased pressure on the components of the actuating device from being exerted via the edges of the brake pad due to vibrations or diagonal wear on the brake pad. Furthermore, the distance between the brake disc and the brake pad (air gap) allows for a cooling effect in this area.

[0021] The brake pad 2 is made of a metallic material; preferably, gray cast iron or stainless steel is used. Ideally, a ceramic material is used for the insulating body 5; zirconium oxide has proven particularly effective in testing the inventive subject matter.

[0022] In Fig. Figure 3 shows an embodiment of the subject matter of the invention. The brake pad is embedded in an insulating body 11 as a substantially annular disc 10. The side surfaces of the insulating body 11 adjacent to the brake contact surface of the brake pad 10 extend from the annular circumferential surface 12 of the insulating body 11 with a distinct convex rounding toward the piston (piston not shown).

[0023] Fig. 4 again shows in a perspective sectional view the structure of the brake pad 10 and the insulation body 11 with the strongly convex rounding on the ring circumferential surface 12 according to Fig. 3.

[0024] In contrast to the Fig. 1 and Fig. 2 and previously described embodiment consists of the embodiment according to the Fig. 3 or 4, the brake pad 10 is made of a metallic material, namely stainless steel, which is only embedded as a centrally arranged ring in the insulating body 11, which is placed on a sliding piston (not shown).

[0025] The insulating body 11 is made of ceramic material, namely zirconium oxide.

[0026] In its construction with its rounded edges on its ring peripheral surface 12, the insulation body 11 with its advantages corresponds to the construction according to the embodiment according to Fig. 1 or 2. List of reference symbols 1 piston 2 brake pads 3 Pot-shaped attachment on 2 4 Opening of 3 5 insulation bodies 6 Screw / connector 7 brake piston housing 8 Brake system surface 9 Ring circumference 10 Brake pad / annular disc 11 Insulating body 12 Ring circumference

Claims

[1] Device for thermal insulation on an actuating device of a disc brake which can be pressurised with a pressure medium and has a piston sliding in a cylinder for axially displacing the brake pads against a brake disc, in particular a spot-type disc brake with an insulating body made of non- / poorly heat-conducting material for insulating the components of the actuating device from a brake pad, characterized by that a metallic brake pad (2) designed as an annular disc is accommodated in an insulating body (5) made of ceramic material which can be inserted into the piston (1) and is essentially circular in shape, wherein the surface of the insulating body (5) is convexly rounded towards its annular peripheral surface (9) and runs in the direction of the piston (1), the brake pad (2, 10) is made of stainless steel and zirconium oxide is used as the ceramic material for the insulating body (5, 11). [2] Device for thermal insulation on a brake piston, characterized by that the brake pad (2) is essentially circular, pot-shaped, in whose pot-like recess (3) the essentially circular insulating body (5) can be inserted. [3] Device according to one of the preceding claims, characterized by that the brake pad (2, 10) and insulating body (5, 11) can be inserted into the piston (1) in such a way that heat transfers can be completely or largely avoided by largely avoiding direct transitions. [4] Device according to one and / or more of the preceding claims, characterized by their application in spot-type disc brakes for motor vehicles.

Images