Electromechanical brake for a motor vehicle

Abstract

The invention relates to an electromechanical brake (10) for a motor vehicle. The electromechanical brake (10) comprises an electric motor (54) arranged on a brake caliper (14), wherein the electric motor (54) drives at least one spindle drive (42) via a gear unit (50), via which spindle drive brake pads (26) can be applied to a brake disc (22) for braking. The brake caliper (14) is formed from two brake caliper parts (14a, 14b) which are movably mounted relative to one another and on each of which at least one brake pad (26) is arranged. The spindle drive (42) is arranged between the brake caliper parts (14a, 14b) in such a way that the distance between the brake caliper parts (14a, 14b) can be reduced for braking via the spindle drive (42).

Description

[0001] The present invention relates to an electromechanical brake for a motor vehicle. Furthermore, the invention relates to a motor vehicle having such an electromechanical brake. State of the art

[0002] Typically, the service brake is a brake in which a brake piston, together with a brake pad, is pressed onto a brake disc via brake fluid to slow the vehicle. The parking brake, on the other hand, is designed as an electromechanical brake. With the increasing electrification of motor vehicle components, the service brake is also to be designed as an electromechanical brake, thus eliminating the need for brake fluid and the associated complex valve and line assembly. Such an electromechanical brake could also significantly reduce maintenance requirements.

[0003] EP 0 944 781 B1 discloses an electromechanically actuated brake which presses a brake pad against a brake disc for braking. The brake comprises a spindle drive unit having a spindle and spindle nut, the spindle being connected to the brake pad. The spindle nut is fixedly connected to a sleeve which surrounds the spindle nut on the outside. The sleeve is rotatably mounted in the brake caliper via bearings. Permanent magnets are arranged in the sleeve so that they form a rotor of an electric motor. The sleeve is surrounded by a stator, via which the rotor is driven. By appropriate rotation of the spindle nut, the brake pad can be moved axially to apply a braking force.

[0004] The object underlying the invention is to provide an electromechanical brake for a motor vehicle with which a high braking force can be applied and which, despite this, has a low weight.

[0005] The object is achieved by an electromechanical brake for a motor vehicle having the subject matter of patent claim 1. Preferred embodiments can be found in the dependent claims. Disclosure of the invention

[0006] The invention specifies an electromechanical brake for a motor vehicle. The electromechanical brake comprises an electric motor arranged on a brake caliper. The electric motor drives at least one spindle drive via a gear unit, via which spindle drive brake pads can be applied to a brake disc for braking. The brake caliper is formed from two brake caliper parts that are movably mounted relative to one another, each of which has at least one brake pad arranged on it. The spindle drive is arranged between the brake caliper parts in such a way that the distance between the brake caliper parts can be reduced for braking via the spindle drive.

[0007] According to the invention, the brake caliper parts are arranged on both sides of the brake disc. In contrast to the prior art, no brake piston is provided which applies a braking force to a brake pad. Instead, the braking force is applied to the brake pad by means of the spindle drive through the entire brake caliper part. In contrast to a brake piston, the braking force is therefore not applied at a specific point, but distributed over a larger area. Since the brake caliper parts already have sufficient rigidity, a rigid pressure plate for the brake pad is not necessary. The pressure plate can therefore be made much smaller and thinner, which saves weight. It is also possible to make the brake pad much longer, so that greater braking performance and durability can be achieved. This makes the electromechanical brake suitable for heavier and / or more powerful vehicles.

[0008] According to the invention, both brake caliper parts are mounted so that they can move relative to each other. This makes it possible to adjust the clearance between the brake pads and the brake disc. This is particularly advantageous in dangerous situations, allowing for faster emergency braking. The brake pads can also be quickly separated from the brake disc after braking, significantly reducing residual drag torque.

[0009] In a preferred embodiment of the invention, the spindle drive is encapsulated. Encapsulated means that structural measures are provided to protect the spindle drive from external environmental influences. The spindle drive is thus sealed off from the environment. This prevents dirt or moisture from impairing the spindle drive's function. The durability of the electromechanical brake is thus improved.

[0010] In a further preferred embodiment of the invention, the spindle drive is encased in a cylindrical housing, which protects the spindle drive from external influences. The cylindrical housing offers a simple way to protect the spindle drive from external influences. In contrast to integrating the spindle drive into the brake caliper, the spindle drive remains accessible for maintenance purposes via the cylindrical housing.

[0011] Alternatively, the spindle drive has at least one bellows, which protects the spindle drive against external influences. The bellows surrounds the spindle drive and can adjust its axial length according to the axial movement of the spindle drive. No complex design measures are required for the bellows, so the bellows economically protect the spindle drive from external influences. The bellows also allows the required installation space for protection against external influences to be kept small. This allows for an electromechanical brake with a reduced overall height.

[0012] Preferably, the spindle drive is integrated into the brake caliper. By integrating the spindle drive into the brake caliper, the spindle drive is protected from external environmental influences by the brake caliper. Therefore, no additional design measures are required to protect the spindle drive. Furthermore, integrating the spindle drive into the brake caliper reduces the radial height of the electromechanical brake.

[0013] In an advantageous development, the brake caliper parts are movably guided on at least one guide part. The guide part, which is connected to the vehicle, makes it possible to mount both brake caliper parts movably relative to one another. Preferably, two guide parts are provided, which are arranged at the ends of the brake caliper parts. These guide parts prevent the brake caliper parts from tilting during braking. Accordingly, even contact of the brake pad with the brake disc can be ensured during braking. This achieves even wear of the brake pad, so that the brake pad can be thinner overall.

[0014] Advantageously, two spindle drives are arranged, which act on the brake caliper parts. Using two spindle drives has the advantage that the brake pads can be made even longer, since the brake caliper parts experience braking force at two points rather than just the center. This allows for better distribution of the braking force across the brake caliper part. Likewise, with two spindle drives, each spindle can have a smaller diameter, since the total braking force is distributed across two spindle drives. This further reduces the radial size.

[0015] In a further advantageous embodiment, the width of the brake pad is at least twice as large as its height. Such a brake pad has the advantage of enabling high braking force. Furthermore, the larger friction surface allows for a thinner brake pad design. The larger surface area of ​​the brake pads also improves cooling of the brake pads after braking, preventing the brakes from overheating even during long downhill rides or when driving aggressively.

[0016] According to a practical embodiment, at least one resilient return element is arranged between the brake caliper parts, via which a force is applied in a brake release direction. The resilient return elements allow the brake caliper parts to return to their original position even in the event of a failure of the electric motor. This improves the reliability of the electromechanical brake.

[0017] The invention additionally provides a motor vehicle having such an electromechanical brake. Such a motor vehicle has the advantages and properties described above.

[0018] Embodiments of the invention are illustrated in the drawing and explained in more detail in the following description. It shows: Fig. 1 Side view of an electromechanical brake for a motor vehicle according to a first embodiment of the invention, Fig. 2 Top view of the electromechanical brake after Fig. 1, Fig. 3 Side view of an electromechanical brake for a motor vehicle according to a second embodiment of the invention, Fig. 4 Top view of the electromechanical brake after Fig. 3, Fig. 5 Top view of an electromechanical brake for a motor vehicle according to a third embodiment of the invention, Fig. 6 Side view of the electromechanical brake after Fig. 5, Fig. 7a Representation of a brake disc and a brake pad according to the state of the art, and Fig. 7b Illustration of a brake disc and a brake pad according to the invention.

[0019] In Fig. Figure 1 shows a side view of an electromechanical brake 10 for a motor vehicle according to a first embodiment of the invention. The electromechanical brake 10 comprises a brake caliper 14, which is formed from a first brake caliper part 14a and a second brake caliper part 14b. These brake caliper parts 14a, 14b are arranged so as to be movable relative to one another. Both brake caliper parts 14a, 14b are movably guided to a brake caliper holder 18 and fastened to the vehicle. The brake caliper parts 14a, 14b are arranged on either side of a brake disc 22. Each brake caliper part 14a, 14b has a brake pad 26 aligned with the brake disc 22. This brake pad 26 is attached directly to the respective brake caliper part 14a, 14b.

[0020] Each brake caliper part 14a, 14b has an extension 30 which projects beyond the brake disc 22 on an upper side to an opposite side of the brake disc 22. Each extension 30 has an end section 34 aligned parallel to the brake pad 26, which are arranged opposite one another. Between these end sections 34, a cylindrical housing 38 of a spindle drive 42 is provided. This cylindrical housing 38 has two housing parts 38a, 38b which can be moved one inside the other, via which a length of the cylindrical housing 38 can be changed via a spindle 46 arranged thereon. The distance between the end sections 34 can be increased via the cylindrical housing 38, so that the brake caliper parts 14a, 14b can be applied to the brake disc 22 for braking. In the same way, the distance between the end sections 34 can be reduced so that the brake caliper parts 14a, 14b can be spaced from the brake disc 22.

[0021] Fig. 2 shows a plan view of the electromechanical brake 10 according to Fig. 1. This figure shows that the spindle 46 is mechanically connected to a gear unit 50, which is driven by an electric motor 54. In the exemplary embodiment shown here, the gear unit 50 is arranged orthogonally to the spindle 46. This allows the axial length of the electromechanical brake 10 to be kept small. In this exemplary embodiment, the electric motor 54 extends in the direction of the brake caliper parts 14a, 14b. In the exemplary embodiment shown, the electric motor 54 is arranged next to the first brake caliper part 14a. This also allows the axial length of the electromechanical brake 10 to be kept small.

[0022] In Fig. 2 additionally shows that the brake caliper holder 18 forms two guide parts 58 designed as pins, on which the brake caliper parts 14a, 14b are guided. The spindle drive 42 is arranged centrally between the guide parts 58. Between the first brake caliper part 14a and the second brake caliper part 14b, resilient return elements 62 are arranged around the guide parts 58, via which the brake caliper parts 14a, 14b can be pressed apart, so that the brake pads 26 can be released from the brake disc 22.

[0023] Fig. Figure 3 shows a side view of the electromechanical brake 10 for a motor vehicle according to a second embodiment of the invention. This embodiment differs from that shown in Fig. 1 in that no cylindrical housing 38 is provided for the spindle drive 42. This allows the overall height of the electromechanical brake 10 to be reduced. To protect the spindle drive 42 from external influences such as dirt or moisture, a bellows 66 is arranged around the spindle drive 42.

[0024] Fig. 4 shows a plan view of the electromechanical brake 10 according to Fig. 3. This figure also differs from the Fig. 2 in that no cylindrical housing 38 is provided for the spindle drive 42. In order to apply a restoring force to the brake caliper parts 14a, 14b, resilient return elements 62 are also provided between the brake caliper parts 14a, 14b.

[0025] In Fig. Figure 5 shows a plan view of the electromechanical brake 10 for a motor vehicle according to a third exemplary embodiment of the invention. This exemplary embodiment differs from the previous exemplary embodiments in that, instead of a single spindle drive 42, two spindle drives 42 are provided. A spur gear 70 is driven via the gear unit 50, which engages with a spindle spur gear 74 of each spindle 46. Two spindle drives 42 are thus driven via an electric motor 54. This allows each spindle drive 42 to be made smaller. Likewise, the spindle drives 42 are not arranged centrally between the guide parts 58. Rather, the spindle drives 42 are arranged distributed circumferentially around the brake disc 22. This allows the overall height of the electromechanical brake 10 to be reduced.

[0026] Fig. 6 shows a side view of the electromechanical brake 10 according to Fig. 5. This embodiment differs from the previous embodiments in that the spindle drive 42 is integrated into the brake caliper 14. The spindle drive 42 is thus protected from external influences by the brake caliper 14. This eliminates the need for the bellows 66 or the cylindrical housing 38. By integrating the spindle drive 42 into the brake caliper 14, it is also possible to further reduce the overall height of the electromechanical brake 10. The extensions 30 with the end sections 34 can also be omitted.

[0027] Fig. Figure 7a shows a representation of a brake disc 22 and a brake pad 26 according to the prior art. It can be seen that a brake piston 78 pressing the brake pad 26 against the brake disc 22 acts only centrally on the brake pad 26. In the remaining areas of the brake pad 26, the braking force is significantly lower due to elastic deformation of the brake pad 26 or a pressure plate. In contrast, in Fig. 7b, for the brake caliper 14 according to the invention, it is shown that the braking force acts evenly across the entire brake pad 26. Thus, with the present invention, greater braking power can be applied to the brake disc 22 for the same brake pad size. The pressure plate for the brake pad 26 can also be made thinner. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 0 944 781 B1

[0003]

Claims

[1] Electromechanical brake (10) for a motor vehicle, comprising an electric motor (54) which is arranged on a brake calliper (14), wherein the electric motor (54) drives at least one spindle drive (42) via a gear unit (50), via which spindle drive brake pads (26) can be applied to a brake disc (22) for braking, characterized by in that the brake calliper (14) is formed from two brake calliper parts (14a, 14b) which are mounted movably relative to one another and on each of which at least one brake pad (26) is arranged, wherein the spindle drive (42) is arranged between the brake calliper parts (14a, 14b) in such a way that a distance between the brake calliper parts (14a, 14b) can be reduced for braking via the spindle drive (42). [2] Electromechanical brake (10) according to claim 1, characterized by that the spindle drive (42) is encapsulated. [3] Electromechanical brake (10) according to claim 1 or 2, characterized bythat the spindle drive (42) is encased in a cylindrical housing (38) by which the spindle drive (42) is protected against external influences. [4] Electromechanical brake (10) according to claim 1 or 2, characterized by that the spindle drive (42) has at least one bellows (66) by means of which the spindle drive (42) is protected against external influences. [5] Electromechanical brake (10) according to claim 1 or 2, characterized by that the spindle drive (42) is integrated in the brake calliper (14). [6] Electromechanical brake (10) according to one of the preceding claims, characterized by that the brake calliper parts (14a, 14b) are movably guided on at least one guide part (58). [7] Electromechanical brake (10) according to one of the preceding claims, characterized by that two spindle drives (42) are arranged which act on the brake calliper parts (14a, 14b). [8] Electromechanical brake (10) according to one of the preceding claims, characterized by that a width of the brake pad (26) is at least twice as large as a height of the brake pad (26). [9] Electromechanical brake (10) according to one of the preceding claims, characterized by that at least one resilient return element (62) is arranged between the brake calliper parts (14a, 14b), via which a force is applied in a brake release direction. [10] Motor vehicle comprising an electromechanical brake (10) according to one of the preceding claims.

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