Brake caliper and disc brake with hydraulically elastic brake pistons

Abstract

The invention relates to a disc brake having a novel hydraulic brake caliper, which is suitable in particular for systems and vehicles in which high braking forces are required for braking rotating system or vehicle parts, in particular wind turbines. The invention relates in particular to a brake caliper for a disc brake, in which the conventional hydraulically actuated brake pistons are replaced by hydraulically expandable elastomer cushions which are flexible in shape and design.

Description

[0001] Brake caliper and disc brake with hydraulic-elastic brake pistons

[0002] The invention relates to a disc brake with a novel hydraulic brake caliper, which is particularly suitable for systems and vehicles in which high braking forces are required to brake rotating system or vehicle parts.

[0003] The invention relates in particular to a brake caliper for a disc brake in which the usual hydraulically actuated brake pistons are replaced by hydraulically variable, flexible elastomer cushions of shape and design.

[0004] The disc brake according to the invention is particularly intended for use as an azimuth brake in wind turbines and is ideally suited for this purpose.

[0005] Conventional disc brakes according to the state of the art, for example in automotive engineering, have a metal disc rotating on the hub or axle of a wheel or a drive disc, which is braked by pressing on it with laterally or axially mounted hydraulically or electrically movable brake pistons or brake calipers equipped with brake pads. Although modern disc brakes of the state of the art already meet many of these requirements, they suffer from a fundamental problem: susceptibility to wear and the often associated leakage, which are caused by the constant movement of the pistons and the lateral forces generated during braking.

[0006] Disc brakes are not only used in vehicle construction, but are also used in wind turbines as azimuth brakes.

[0007] The purpose of an azimuth brake is to hold the nacelle of a wind turbine in its azimuthal position, thus reducing or preventing the nacelle's rotational movement. The azimuth brake features a horizontally aligned, ring-shaped brake disc on which a large number of brake shoes are arranged, allowing a sufficiently high holding force to be exerted on the brake disc. Typically, azimuth brakes in wind turbines are hydraulically operated, which means the aforementioned problems are always present.

[0008] The active braking systems used to date for yaw brakes have a number of disadvantages. For example, the hydraulic cylinders or electric drives used must be designed for high forces, which makes them expensive. Furthermore, hydraulic systems carry the risk of hydraulic fluid contaminating the braking surface due to leaks in the hydraulic system, necessitating the replacement of all brake pads and a thorough cleaning of the brake disc. This increases system downtime. Damaged brakes also increase the risk of uncontrolled system behavior, particularly due to uncontrolled slewing of the nacelle and rotor of a wind turbine.

[0009] For this reason, azimuth brakes were proposed for wind turbines, which could avoid or at least reduce the problems of wear and leaks.

[0010] EP 1 637 761 A1 describes a disc brake which can be used in particular as an azimuth brake and which has a hydraulically movable elastic layer instead of a conventional brake piston. An elastomer ring is arranged between the elastic layer and the brake pad attached to a carrier plate. This elastomer ring is intended to prevent elastic material from penetrating the space between the carrier plate and the brake shoes at high braking pressure. Even if the hydraulic fluid which presses the elastic layer towards the brake disc is not directly connected to the carrier plate and the brake pad in this system, it cannot always be prevented that hydraulic fluid penetrates to the brake pads and the brake disc under very high braking forces or due to material wear or fatigue of the elastic layer, and thus contaminates them and impairs their function.

[0011] WO 2022 / 258323 A1 describes an elastomer spring for an azimuth brake of an azimuth drive for tracking a nacelle of a wind turbine, which comprises an elastomer body made from one piece with an upper and lower side facing in a spring direction of the elastomer body for transmitting spring forces and a prestressing element connecting the upper and lower sides, which prestressing element has a concavely curved outer surface.

[0012] WO 2005 / 038286 A1 describes an azimuth brake for wind turbines, with at least two pairs of brake shoes arranged on a common brake disc, each pair being assigned an actuator, wherein each actuator has a lever which can be pivoted about an axis perpendicular to the plane of the brake disc, and a gear for converting the pivoting movement of the lever into an axial pressing movement of the brake shoes against the brake disc, and wherein the levers of the actuators are coupled by a common drive

[0013] DE 10 2008 008437 describes an azimuth brake for azimuthally adjustable nacelle of a

[0014] Wind turbine, wherein the azimuth brake comprises a brake disc and at least one brake calliper having at least one brake pad, wherein the brake disc is fixedly connected to the tower and the brake calliper is fixedly connected to the nacelle, wherein at least one brush (22) is fixedly arranged with respect to the brake calliper, the brush facing of which is in contact with the brake disc.

[0015] DE 102006 024023 proposes an azimuth brake for wind turbines, which consists of appropriately arranged brake blocks and devices for absorbing the braking force, which have expansion elements that expand spatially when heated, which serve to actuate or release the brake, and which are provided with a heating device.

[0016] DE 19629168 C1 describes a wind turbine which has a tower brake element and a nacelle brake element made of hydraulically or pneumatically clamped or clampable ring bushings which are arranged concentrically to one another and whose axes run parallel to the pivot axis of the nacelle.

[0017] Finally, DE 102011 010830 A1 discloses a pneumatic yaw brake for wind turbines, in which one or more flat pneumatic actuators act between the underside of the machine frame and the top of a stationary bearing ring. The pneumatic actuators consist of an elastic membrane mounted in a pressure-tight manner on a flat pressure plate, and the membrane is inflated or shrunk by increasing or decreasing the air pressure in the space between the membrane and the pressure plate. The main disadvantage of this solution is that air pressure often cannot generate the necessary high braking forces in a larger wind turbine.

[0018] This also applies to the other state-of-the-art braking systems described above, provided no hydraulic power generation is used. While conventional hydraulic systems can achieve higher braking forces, they often suffer from leakage and / or wear.

[0019] The task was therefore to provide a disc brake for systems or vehicles requiring particularly high braking forces, which does not have the disadvantages mentioned or at least has significantly reduced them while at the same time being highly effective and, in addition, easy to maintain and cost-effective to produce.

[0020] The problem has been solved according to the features of the appended claims and the following description. The subject of the invention is thus a disc brake comprising brake calipers with novel brake pistons in the form of hydraulically elastic cushions.

[0021] In detail, the invention relates to a brake caliper for a disc brake with the following features known per se:

[0022] (i) two opposite brake shoes (2a)(2b),

[0023] (ii) at least one component (1) serving as a brake piston, which

[0024] - is mounted on the inside of or in one of the two brake shoes (2a)(2b) of the brake calliper (2) in such a way that it is axially movable with respect to the opposite brake shoe and leaves a space (19) between the brake shoes for a brake disc (17),

[0025] - a brake pad (12) or a brake pad carrier (11) to which a brake pad (12) is attached on the side facing the opposite brake shoe; and

[0026] (iii) a hydraulic device (8)(16)(21 ), which also has a connection element (5) to the elastomer cushion, for supplying a hydraulic fluid (8).

[0027] The brake calliper according to the invention also includes designs known in the prior art and often used in disc brakes, in which two opposing brake pistons (1) (two-piston system) with respective brake pad carriers (11) and / or brake pads (12) are movable axially on both sides to the brake shoes (2a)(2b), leaving a space for a brake disc (17) to be arranged between the brake shoes.

[0028] On the other hand, the invention also includes designs in which only one movable brake piston (1) (single-piston system) with a brake pad carrier or a brake pad is arranged in one of the two brake shoes, while the opposite brake shoe does not have a movable piston, but a fixedly mounted brake pad carrier (11) and / or a brake pad (12).

[0029] Furthermore, the invention comprises, as an essential feature of the invention, a corresponding brake calliper in which the component (1) serving as a brake piston or the components (1) serving as a brake piston have or have a self-contained elastomer cushion (6) whose volume can be hydraulically changed, which causes and controls the axial movement of the brake pads (12) or of the brake pad carrier (11) equipped with brake pads.

[0030] The brake calliper in question comprises in detail essentially flat elastomer cushions (6), each elastomer cushion (a) according to the invention having opposite, elastic side parts which are connected to one another via a circumferential curved edge and enclose a cavity (9),

[0031] (b) is adapted with regard to its shape, size and orientation to the geometry of the brake shoes (2a)(2b) and the brake pad carrier (11) or the brake pad (12) and is mounted or housed in or on the brake calliper (2) in such a way that its flat side parts are arranged perpendicular to the brake pad (12) or the brake pad carrier (11) with the brake pad (12), and

[0032] (c) has a connecting element (5) for a hydraulic fluid (8), with which it is pressure-tightly connected in a specific area (7) of the elastomer cushion and through which hydraulic fluid is pressed into the cavity (9) of the cushion during braking operation in order to tension it in such a way that an axial movement of the brake pad carrier (11) or the brake pad (12) in the direction of the opposite brake shoe (2a)(2b) and thereby a pressing of the brake pad (12) against a brake disc (17) located in the intermediate space (19) takes place.

[0033] Such an elastomer cushion as an essential element of a novel brake piston rests on the outside of a movable brake pad carrier (11) or a brake pad (12) or is connected to them.

[0034] The brake pad carrier (11) itself is provided with a brake pad (12) on the inside and is guided by a corresponding recess in the respective brake shoe (2a)(2b). The elastomer cushion of the brake shoe (2a)(2b) is pressure-tightly connected to a connecting element (5) for a hydraulic fluid (8).

[0035] This design thus allows the elastomer cushion (6) with the connecting element (5) and, if applicable, with the permanently connected brake carrier or the permanently connected brake pad to be mounted as a structural unit separately from the other parts of the brake calliper or the disc brake and to be easily replaced.

[0036] Preferably, an elastomer cushion occupies substantially the entire outer surface of the brake pad carrier or the brake pad in order to exert the most uniform hydraulic pressure possible on the brake pad carrier, generated by the elastomer cushions, during brake operation. As a result, due to its axial displaceability, the brake pad carrier is pressed against a brake disc (17) provided centrally in the brake caliper, utilizing the distance or clearance existing in the non-braking state.

[0037] The gap (19) between the brake disc and the brake pad (12). The elastomer cushions are thus shaped to match the brake shoes and are aligned with their flat side axially to the brake pad carriers and the brake disc. Depending on the application, the layer thickness of the elastomer cushion can be between 2 mm and 12 mm.

[0038] A cavity (9) is provided inside each cushion, which is connected to the brake's hydraulic system. The hydraulic fluid (8) is introduced under pressure into the cavity (9) of the respective cushion via supply lines (16) that run through the connecting elements (5). Water or oil are particularly suitable as hydraulic fluids.

[0039] During braking, hydraulic fluid (8) is forced into the hollow chambers (9) of the two elastomer cushions. Due to their arrangement and fixation in the brake shoes, the cushions expand or inflate primarily axially in the direction of the brake disc (17), thus becoming preloaded. As a result, the brake pad carriers (11) or brake pads (12) that are externally adjacent to or connected to the elastomer cushions are also displaced toward the brake disc or the opposite brake shoe, so that the brake pads or the brake pads attached to the inside of the pad carriers are pressed against the brake disc.

[0040] If the braking process is terminated by reducing or eliminating the hydraulic pressure, the elastomer cushions contract, shrinking the cavity (9), and the distance (19) between the brake pads (12) and the brake disc (17) is restored by a correspondingly directed movement of the brake pad carriers (11). Alternatively, the brake pressure can be maintained while the brake disc is moved, or the brake pressure (braking force) can be reduced, so that no gap is created.

[0041] It is advantageous according to the invention to take measures which ensure that the elastomer material of the cushions does not penetrate into the narrow space or the narrow gap between the brake caliper and the movable brake pad carrier (11) or brake pad (12) during braking operation, i.e. under hydraulic pressure, because this could lead to the brake being blocked. This can be achieved by maintaining a gap (27) in the area between the perpendicularly positioned brake caliper and brake pad carrier on the one hand and the adjacent curved edge of the elastomer cushion on the other. In the simplest case, the elastomer cushion or at least its curved border is made of an elastic material which has a Shore hardness of > 80, preferably > 90. It has been shown that such a harder elastomer material cannot penetrate into the critical gaps in the aforementioned area due to the hydraulic pressures which occur.

[0042] It is also possible to prevent the penetration of elastomer between the brake pad carrier and the brake calliper guiding it by means of measures other than harder cushion material suitable for such purposes, for example by inserting an additional ring made of a much harder material, which prevents direct contact of the elastomer cushion with the critical area mentioned.

[0043] In one embodiment of the invention, the elastomer cushion (6) according to the invention has, in brake-free operation, an annular bead (23) bent around a defined bending radius (10), which is arranged along the circumferential bent edge of the elastomer cushion and rests on the lateral outer circumference of the brake pad carrier (11) or directly on the brake pad (12) or is connected to them.

[0044] During braking operation, i.e. when the elastomer cushion is stretched with a correspondingly enlarged hollow space filled with hydraulic fluid (9), the elastic material of the bead is bent straight, increasing the volume of the elastomer cushion, whereby the elastomer material is subjected to a pre-tension, which is partly used to ensure the necessary axial expansion of the elastomer cushion at the same braking pressure as the brake fittings gradually wear out.

[0045] In a further embodiment of the invention, the elastomer cushion (6) can have one or more additional beads (24) arranged continuously or partially circumferentially on the side of the elastomer cushion that faces the brake pad carrier (11) or the brake pad (12) and rests against it or is connected to it. This provides additional prestressed areas with additional potential volumes for hydraulic fluid during braking, so that the braking shock can be maintained as the brake pad wear increases.

[0046] It has been shown that the bending radii (10) of the beads (23)(24) should be at least 0.5 to 3 times, preferably 0.5 to 2 times, as large as the layer thickness of the elastomer cushion in order to achieve the desired prestressing effect described.

[0047] In one embodiment of the invention, the elastomer cushions according to the invention are completely embedded in correspondingly shaped and sized recesses (25) in the brake shoes (2a)(2b) of the brake caliper (2). As already mentioned, this is preferably such that the elastomer cushions can expand or inflate primarily in the axial direction toward the brake disc, increasing the hydraulic volume (9). The recesses (25) in the brake shoes of the brake caliper can preferably have rounded or beveled portions (22) in the areas where the elastomer cushion (6) directly rests against the brake caliper or with which it is in direct contact.

[0048] The elastomer cushions (6) preferably each have a single opening that provides access to the cavity (9) within the cushion. This opening is connected to the connecting element (5) in a pressure-tight manner. According to the invention, it has been found advantageous if the hydraulic connecting element (5) is designed and connected to the elastomer cushion (6) in such a way that the surface area transmitting the hydraulic pressure to the elastomer cushion is larger than the contact surface between the elastomer cushion and the connecting element (5), which is responsible for the seal. This can prevent hydraulic fluid from escaping at the connecting element under certain circumstances.

[0049] In one embodiment of the invention, the connecting element (5) can be sealed against the metal by means of an elastic sealing ring (20) where it is connected to the brake calliper (2).

[0050] In principle, it is sufficient for each brake shoe (2a)(2b) to have a single brake piston element (1) with a supply line (16)(21) for the hydraulic fluid. However, two or more brake piston elements (1) can also be integrated into one brake shoe for better and faster pressure distribution.

[0051] The brake calipers according to the invention described are ideally suited as azimuth brakes for wind turbines in order to brake and lock the nacelle with the rotor blades, which is mounted on the tower so that it can rotate 360° depending on the wind direction, if necessary.

[0052] Such an azimuth brake then has a plurality of, for example 6 - 12, brake calipers according to the invention, which are evenly distributed by means of fastening devices (4) attached to a horizontally aligned, optionally disc-shaped ring serving as a brake disc (17), to which the nacelle is connected.

[0053] The brake caliper according to the invention and the disc brakes equipped with it offer the following advantages over conventional hydraulic brakes of the same type used for the same purposes: • Due to the design of the elastomer cushion and its connection and arrangement in the brake caliper, the hydraulic fluid is completely enclosed and does not come into contact with the metal parts of the brake caliper. This eliminates the need for strength-damaging notches or undercuts in the metal parts for inserting sealing rings or the like. The elastomer cushions can be easily kept completely sealed, even at high hydraulic pressures.

[0054] • If the hydraulic lines are connected directly to the elastomer cushion via the connecting element, there is no need to worry about possible leakage problems in the brake caliper.

[0055] • In the simplest case, the elastomer layer of the cushion is sufficiently hardened, with a Shore hardness of at least 80, for example 95, to prevent the elastomer from being indented or crushed into the joints between the carrier plate and the brake caliper. Even at high hydraulic pressures of, for example, more than 300 bar, the material does not penetrate the joints, so no additional measures such as inserting correspondingly harder elements are required.

[0056] • Strength-enhancing radii can be designed as desired in the brake caliper.

[0057] • The elastomer cushions are easily replaceable compared to conventional brake pistons.

[0058] • Due to the pre-tensioning created by the high radii, little tensile stress is created even in the case of large changes in length during the expansion of the elastomer cushions, which proves to be gentle on the material.

[0059] • By applying appropriate additional preload and volume-generating beads, a uniform braking force can be exerted on the brake disc over a wide range when the brake pads begin to wear, at the same hydraulic pressure, by adjusting the pad carriers accordingly and consuming the additional volume. The deformation behavior of the elastomer cushion according to the invention ensures the required service life. Furthermore, the lower material stress in the elastic layer leads to small restoring forces even during large movements, so that the tensile forces in the elastic layer of the cushion have little or no effect on the braking force and service life, and thus also less effect on the tensile-loaded elastomer cushions. The invention is explained in more detail below with reference to the figures:

[0060] Fig. 1 shows a brake caliper (2) according to the invention, which has a circular arc shape. It consists of a right and left brake shoe (2a)(2b), which are arranged parallel to each other and separated by a gap (19). The resulting space is intended for a brake disc (not shown here). The brake shoes are equipped with a connection element (5) for hydraulic lines. Holes for fastening devices (4) can be seen on the inner edge of the circular brake caliper.

[0061] Fig. 2 shows a three-dimensional cross-section of the brake caliper according to the invention as shown in Fig. 1. Each brake shoe (2a)(2b) of the brake caliper (2) has an element (1) acting as a brake piston embedded therein. This element essentially consists of an elastomer cushion (6) which is firmly and pressure-tightly connected on the outside in a connection area (7) to a connection element (5) provided with a profile. Each of the two elastomer cushions (6) has a variable cavity (9) on the inside which is filled with hydraulic fluid (8) under pressure depending on the operating state of the brake. On the inside, the elastomer cushion is connected to one side of a brake pad carrier (11), which in this embodiment serves as a carrier plate for a brake pad (12) which is attached to the other side of the carrier plate.A variable gap (19) is maintained between the two opposing carrier plates equipped with the brake pads for the brake disc (17) (not shown in the image). Hydraulic lines (16) supply hydraulic pressure to the elastomer cushions (6), causing the carrier plates with the brake pads to move axially toward each other and, if a brake disc is present, to be pressed against it, initiating the braking process.

[0062] Fig. 3 shows an elastomer cushion (6) according to the invention without brake calliper in the non-installed state with a connecting element (5) for the hydraulic line.

[0063] (A) The elastomer cushion has a circumferential bead (23) with a bending radius (10) on one side facing the brake pad carrier (not shown). The image shows a brake-free / pressure-free state, in which the cavity (9) has only a small empty volume without a significant amount of hydraulic fluid (8). (B) shows the same elastomer cushion in braking operation, in which the bead (23) is compressed (23a) to provide additional volume. The cavity (9) is significantly larger than in the brake-free state due to a corresponding expansion of the cushion as a result of the hydraulic fluid being forced in. Fig. 4 (A) and (B) shows an elastomer cushion comparable to Fig. 3, but with

[0064] Elastomer cushions have an elongated shape. In principle, elastomer cushion pistons according to the invention can be of any shape.

[0065] Fig. 5 (A)(B) (A) shows a section of a disc brake with built-in

[0066] Elastomer cushion (6) and a brake disc (17) in the brake-free state.

[0067] The two elastomer cushions (6), which are fitted into corresponding recesses in the brake shoes (2a)(2b) and held in place with fasteners (15), are unfilled (empty volume (9)) and have a circumferential bead (23) with a bending radius (10). The elastomer membrane of the cushions is pressure-tightly connected to a profile structure of the connecting element (5) in the connection area (7). The connecting elements are also provided with optional sealing rings (20) opposite the brake shoes. Hydraulic lines (16) are located within the brake shoes and are connected to the connecting elements (5). In the untensioned state of the elastomer cushion shown, an annular gap (27) is provided in the corner between the brake pad carrier (11), brake caliper, and bead (23). This gap serves to keep the elastomer material of the cushion away from the joint between the brake caliper and the carrier plate / brake pad.Furthermore, it can be seen that in this embodiment of the invention, the brake caliper (2a)(2b) has recesses (25) for the elastomer cushions (6) as well as curves or bevels (22) in the areas of the brake caliper where the elastomer cushion (6) rests directly against metal. Fig. 5(B) shows a single hydraulic elastomer brake piston consisting of an elastomer cushion (6) according to the invention in the unfilled state with an outer annular bead (23) running around the circumference of the cushion and a second inner circumferential or partially circumferential bead (24) with the same or different bending radius (10), wherein the elastomer cushion in turn rests against a carrier plate (11). The brake pad (12) has been omitted from this figure. Due to the unfilled state, the cavity (9) has only a small or negligible volume. The annular gap (27) can also be seen here.

[0068] Fig. 6 shows a similar disc brake as described in Fig. 5 (A) with still intact brake pads (12), but with filled elastomer cushions in braking operation, in which the volume-increasing beads (23) are straightened.

[0069] Fig. 7 shows the same brake caliper as shown in Fig. 6, but with largely worn brake pads (12). To compensate for the reduction in thickness of the brake pad, the elastomer cushion according to the invention expands, enlarging the hollow space (9) filled with hydraulic fluid (8) until the reduction in thickness of the brake pad is compensated for again without any loss of braking force. Fig. 8 shows a disc brake according to the invention in the brake-free state, analogous to

[0070] Fig. 5, but with hydraulic connections directly for the unfilled elastomer cushions, or their connecting elements (5). Fig. 9 illustrates the different operating states of the hydraulic-elastic brake piston according to the invention. Each of the following is shown

[0071] Elastomer cushion (6) which is vulcanized to a connecting element (5) and rests against a carrier plate (11). The left image corresponds to the brake-free state, whereby the elastomer cushion (6) has a circumferential bead (23) with a bending radius (10). The elastomer cushion rests against the carrier plate in the area of ​​the bead. Due to the curvature of the bead, a circumferential free gap (27) is created between the cushion and the carrier plate in the

[0072] Area of ​​the circumferential joint formed by the movable carrier plate (11) and the brake shoe (not shown). The bead (23) also means that, apart from the area of ​​the bead itself, the elastomer cushion does not fully contact the carrier plate when the brake is not being applied. The middle image corresponds to a state under braking. Due to the bending radius (10) of the bead (23) in the left image, the elastic membrane of the elastomer cushion (6) has an effectively larger surface area in this area than necessary. If hydraulic fluid is now pumped into the cavity (9) in a first step, the elastic membrane presses against the brake pad carrier (11) in the area of ​​the beads, compressing it. This gives the elastic layer a larger potential volume (23a). The gap (27) becomes smaller in cross-section under braking conditions, i.e. at full hydraulic pressure, but should ideally remain unchanged.By selecting an elastomer material with a Shore hardness > 90, the closing or even penetration of elastomer material into the gap between the elastomer cushion and the brake pad carrier (11) can be prevented. The right-hand image shows the condition when the elastomer cushion expands further due to brake pad wear. The additional potential volume gained through compression is now used up again. This has the advantageous effect of reducing the tensile length required for expansion and thus the tensile stress on the elastic layer of the cushion, thereby enabling large movements of the brake pad carrier. shows a plan view (top image) and a perspective view (bottom image) of an azimuth brake for wind turbines, which has a plurality of (here: nine) brake calipers according to the invention, which are attached to the inner diameter of a brake ring or brake disc (17).

[0073] Fig. 11 shows a single-piston system of a brake caliper according to the invention, analogous to the two-piston system of Fig. 5. The piston opposite the elastomer cushion

[0074] Brake shoe is firmly mounted via axial fastenings (30) with a brake shoe carrier.

Claims

1. Brake caliper for a disc brake, comprising (i) two opposite brake shoes (2a)(2b), (ii) at least one brake piston (1) which - is mounted on the inside of or in one of the brake shoes (2a)(2b) of the brake calliper (2) in such a way that it is axially movable with respect to the opposite brake shoe and leaves a space (19) between the brake shoes for a brake disc (17), - a brake pad (12) or a brake pad carrier (11) to which a brake pad (12) is attached on the side of the brake pad carrier facing the opposite brake shoe; (iii) a hydraulic device (8)(16)(21) with a connecting element (5) to the at least one brake piston (1), characterized in that the at least one brake piston (1) comprises a self-contained elastomer cushion (6) whose volume can be hydraulically changed and which is designed and arranged such that a change in volume causes an axial movement of the brake pad (12) or of the brake pad carrier (11) equipped with the brake pad (12).

2. Brake caliper according to claim 1, characterized in that the elastomer cushion (6) (a) has opposite, elastic side parts which are connected to one another via a circumferential curved edge and enclose a cavity (9), (b) is adapted with regard to its shape, size and orientation to the geometry of the brake shoes (2a)(2b) and the brake pad carrier (11) or the brake pad (12) and is mounted or housed in or on the brake calliper (2) in such a way that its flat side parts are arranged perpendicular to the brake pad (12) or the brake pad carrier (11) with the brake pad (12), and (c) a connecting element (5) for a hydraulic fluid (8), with which it is connected in a pressure-tight manner in a specific area (7) of the elastomer cushion and through which hydraulic fluid is pressed into the cavity (9) of the cushion during braking operation in order to tension it in such a way that an axial movement of the brake pad carrier (11) or the brake pad (12) in the direction of the opposite brake shoe (2a)(2b) and thereby a pressing of the Brake pad (12) is pressed onto a brake disc (17) located in the intermediate space (19).

3. Brake calliper according to claim 1 or 2, characterized in that between the edges of the elastomer cushion (6), the brake calliper (2) and the brake pad carrier (11) or the brake pad (12) there is an annular gap (27) which, during braking, prevents the penetration of elastomer material between the brake calliper and the brake pad carrier or the brake pad and thus prevents the disc brake from locking.

4. Brake caliper according to one of claims 1 - 3, characterized in that the elastomer cushion (6) is made of an elastomer material which has a Shore hardness > 80, in particular > 90.

5. Brake caliper according to one of claims 1 - 4, characterized in that the elastomer cushion (6) in brake-free operation has an annular bead (23) bent around a bending radius (10), which is arranged along the circumferential bent edge of the elastomer cushion and rests on the lateral outer circumference of the brake pad carrier (11) or the brake pad (12) or is connected thereto.

6. Brake calliper according to claim 5, characterized in that the bead (23) is compressed under prestress during braking operation, whereby an additional potential volume (23a) is provided in this region of the elastomer cushion (6), which is used up again when the brake fitting wears by reducing the prestress.

7. Brake caliper according to claim 5 or 6, characterized in that the elastomer cushion (6) has one or more further beads (24) with additional potential volumes by compression of elastomer material, which beads are arranged continuously or partially circumferentially on the side of the elastomer cushion which is opposite the brake pad carrier (11) or the brake pad (12), and rest against them or are connected to them.

8. Brake caliper according to claim 5, 6 or 7, characterized in that the bending radius (10) of the bead (23)(24) is at least 0.5 to 3 times as large as the layer thickness of the elastomer cushion (6).

9. Brake caliper according to one of claims 1-8, characterized in that the elastomer cushions (6) are completely embedded in correspondingly shaped and sized recesses (25) in the brake shoes (2a)(2b) of the brake caliper (2).

10. Brake calliper according to claim 9, characterized in that the recesses (25) for the elastomer cushions (6) in the brake calliper (2) have rounded portions or bevels (22) in the regions in which the elastomer cushion (6) bears directly against the brake shoes (2a)(2b).

11. Brake caliper according to one of claims 1-10, characterized in that the hydraulic connection element (5) is designed and connected to the elastomer cushion (6) in such a way that the surface area transmitting the hydraulic pressure to the elastomer cushion is larger than the contact surface of the elastomer cushion with the connection element (5) responsible for the tightness, wherein preferably the hydraulic connection element (5) is sealed off from the brake caliper (2) by means of an elastic sealing ring (20).

12. Brake caliper according to one of claims 1 - 11, characterized in that it has two parallel, opposite, axially movable brake pistons (1), each with a self-contained elastomer cushion (6) whose volume can be hydraulically changed (two-piston system).

13. Brake caliper according to one of claims 1 - 11, characterized in that it has only one movable brake piston (1) with a brake pad carrier (1) or a brake pad (12) (single-piston system).

14. Brake caliper according to one of claims 1 - 13, characterized in that the elastomer cushion (6) which is pressure-tightly connected to a connecting element (5) is connected to a brake pad carrier (11) or a brake pad (12) and forms a structural unit with these parts which can be easily replaced.

15. Disc brake characterized in that it comprises a brake caliper according to one of claims 1 - 13 and a brake disc (17) which is arranged in the free space between the brake shoes (2a)(2b).

16. Hydraulic azimuth brake for a wind turbine, characterized in that it comprises a plurality of brake callipers (2) according to claim 13 and a brake disc ring (17) arranged between the two opposite brake pistons (1), to which the nacelle is fastened, each brake calliper (2) being attached to the said brake disc ring in a uniformly distributed manner by means of fastenings (4).

17. A wind turbine comprising a tower, a nacelle and a rotor, characterized in that the nacelle is equipped with a hydraulic azimuth brake according to claim 15.

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