DECENTRALIZED ELECTROHYDRAULIC BRAKE UNIT

Abstract

A decentralized electrohydraulic brake unit for braking a wheel of a motor vehicle. The brake unit includes a brake caliper and a brake caliper piston which can be moved axially in the brake caliper via a drive device and via which hydraulic pressure can be applied to a brake piston. A brake pad is disposed on the brake piston. The brake caliper piston and the brake piston are connected to one another via an elastic element, via which the brake piston can actively be retracted after a braking operation.

Claims

1. A decentralized electrohydraulic brake unit for braking a wheel of a motor vehicle, comprising: a brake caliper; and a brake caliper piston which can be moved axially in the brake caliper via a drive device and via which hydraulic pressure can be applied to a brake piston; a brake pad disposed on the brake piston; wherein the brake caliper piston and the brake piston are connected to one another via an elastic element, via which the brake piston can actively be retracted after a braking operation.

2. The decentralized electrohydraulic brake unit according to claim 1, wherein a diameter of the brake piston is greater than a diameter of the brake caliper piston.

3. The decentralized electrohydraulic brake unit according to claim 2, wherein the diameter of the brake caliper piston is 8-15 mm and the diameter of the brake piston is 20-60 mm.

4. The decentralized electrohydraulic brake unit according to claim 1, wherein a pressure chamber is disposed between the brake caliper piston and the brake piston, and a pressure sensor, via which the pressure chamber can be measured, is provided.

5. The decentralized electrohydraulic brake unit according to claim 1, wherein the elastic element is a spring.

6. The decentralized electrohydraulic brake unit according to claim 1, wherein the elastic element is configured such that, in a rest position, the brake piston is pretensioned in a direction of the brake caliper piston.

7. The decentralized electrohydraulic brake unit according to claim 1, wherein the brake caliper piston is made of a plastic material.

8. A motor vehicle, comprising: a decentralized electrohydraulic brake unit for braking a wheel of a motor vehicle, including: a brake caliper, and a brake caliper piston which can be moved axially in the brake caliper via a drive device and via which hydraulic pressure can be applied to a brake piston, a brake pad disposed on the brake piston, wherein the brake caliper piston and the brake piston are connected to one another via an elastic element, via which the brake piston can actively be retracted after a braking operation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 shows a sectional view of a decentralized electrohydraulic brake unit according to an embodiment example of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0018] FIG. 1 shows a sectional view of a decentralized electrohydraulic brake unit 10 according to an embodiment example of the present invention. The brake unit 10 comprises a brake caliper 14 and a brake jaw 18 disposed on the brake caliper 14. The figure shows only a part of the brake jaw 18. A drive device 22 configured as an electric motor is disposed on the brake caliper 14, via which a brake caliper piston 26 disposed in the brake caliper 14 is axially movable. The brake caliper piston 26 is sealed by a brake caliper seal 30. The brake caliper 14 forms a pressure chamber 34, in which a brake piston 38 is provided is provided in an axially movable manner. The pressure chamber 34 is sealed to the outside by a brake piston seal 42 which is disposed between the brake piston 38 and the brake caliper 14. The pressure chamber 34 is disposed between the brake caliper piston 26 and the brake piston 38 in the brake caliper 14. The electrohydraulic brake unit 10 also comprises a pressure sensor 46, via which a pressure in the pressure chamber 34 can be measured. A brake pad 50 is attached to the brake piston 38 and can be placed against a brake disc 54 to the brake the motor vehicle.

[0019] The brake caliper piston 26 and the brake piston 38 are firmly connected to one another via an elastic means 58, which in this embodiment example is configured as a spring. The spring 58 is disposed coaxially with the brake caliper piston 26 and the brake piston 38. In the embodiment example, it can be seen that a diameter D.sub.BK of the brake piston 38 is greater than a diameter D.sub.BSK of the brake caliper piston 26. Axial movement of the brake caliper piston 26 is therefore greater than axial movement of the brake piston 38.

[0020] Due to the different axial travels of the brake piston 38 and the brake caliper piston 26, it is possible to apply a tensile force to the brake piston 38 after a braking operation via the spring 58. In a rest position, a tensile force is applied to the brake piston 38 so that it is held firmly in said rest position. During the braking operation, on the other hand, a compressive force is applied to the brake piston 38 via the spring 58 so that the brake piston 38 is additionally loaded in the direction of the brake disc 54.

[0021] A compensating bore 62 is provided in the brake caliper 14 in the region of the brake caliper piston 26, via which a pressure change caused by the brake caliper piston 26 can be compensated.