Electromechanical brake

Abstract

The invention relates to an electromechanical brake (10) for a motor vehicle. The electromechanical brake (10) has a modular design, and a first module variant comprises a brake caliper (22) and a brake caliper housing (14) connected to the brake caliper (22), in which a spindle drive unit (34) and a worm gear (54) operatively connected thereto are arranged, which are driven by an electric motor (30). A force can be applied to a brake piston (38) via the spindle drive unit (34) for braking, wherein the second module variant, in addition to the first module variant, comprises a planetary gear (70) likewise arranged in the brake caliper housing (14) between the worm gear (54) and the spindle drive unit (34).

Description

[0001] The present invention relates to an electromechanical brake for a motor vehicle and 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 brake 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 1 030 979 B1 discloses an electromechanical braking device for braking a motor vehicle wheel. The braking device comprises a brake caliper in which an electric motor is arranged. The electric motor drives a spindle drive unit, via which brake pads arranged on a brake caliper of the brake caliper can be applied to a brake disc for braking.

[0004] DE 10 2018 211 443 A1 discloses a pressure generating device for a braking system of a vehicle.

[0005] US 2019 / 0003535 A1 relates to a clamp for a brake unit for overlapping the outer side of a tensioning pulley of a cabin, comprising an electric motor driving a rotating shaft, a first endless screw geared to a first primary gear, and a second endless screw geared to a second primary gear.

[0006] The object underlying the invention is to provide an electromechanical brake for a motor vehicle which can be used for different axial forces with little modification effort and economically.

[0007] 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

[0008] The invention specifies an electromechanical brake for a motor vehicle. The electromechanical brake has a modular design, and a first module variant comprises a brake caliper and a brake caliper housing connected to the brake caliper, in which a spindle drive unit and a worm gear operatively connected thereto are arranged, driven by an electric motor. A force can be applied to a brake piston via the spindle drive unit for braking. The second module variant, in addition to the first module variant, comprises a planetary gear, also arranged in the brake caliper housing, between the worm gear and the spindle drive unit.

[0009] A modular variant is a unit composed of various components that are comparable across different variants. The different variants are constructed in a comparable manner. Different components can also be identical across different variants. This has the advantage that such modular variants are constructed identically, reducing design effort and allowing them to be manufactured on the same production line. This makes manufacturing such an electromechanical brake more cost-effective.

[0010] According to the invention, the second module variant has a planetary gear, via which the ratio between the worm gear and the spindle drive unit is changed compared to the first module variant. This makes it possible to increase the braking force on the brake piston. Despite using essentially identical components, the planetary gear can be used to provide two different module variants, which can be used for different braking forces. With an electromechanical brake constructed in this way, two different module variants can thus be provided economically.

[0011] In a preferred embodiment of the invention, a worm gear of the worm gear has the same diameter in both module variants. Although the two variants are intended to generate different braking forces, the diameter of the worm gear can remain the same. This means that the diameter of the brake caliper housing remains unchanged despite the increased braking force. The electromechanical brake can thus be designed compactly in both variants.

[0012] In a further preferred embodiment of the invention, the electric motor is the same for both module variants. Thus, no additional electric motor needs to be constructed for the different module variants. Furthermore, two different electric motor variants do not need to be kept in stock. By using the same electric motor, it is thus economically possible to provide two different module variants with different braking forces.

[0013] Preferably, the planetary gears are made of a plastic material. Planetary gears made of a plastic material have the advantage of being significantly lighter than metal planetary gears. Furthermore, material costs are reduced when using plastic. Such planetary gears made of plastic material are also easy to manufacture by injection molding. This makes such an electromechanical brake not only lighter but also more economical to produce.

[0014] In an advantageous refinement, the planetary gear unit has a hollow sun gear, through which a spindle of the spindle drive unit is passed. This makes it possible to arrange a parking brake at one axial end. Additionally, the worm gear can be mounted on the spindle. This eliminates the need for additional components to support the worm gear. The hollow sun gear also allows for the use of a large number of planet gears, so that the load is distributed across many tooth meshes. Accordingly, it is possible to select a more cost-effective material, such as plastic, for each planet gear.

[0015] Advantageously, a parking brake is arranged at one end of the spindle, by means of which the spindle can be locked in a braked position. A parking brake can be used to lock the brake during a parking maneuver. By designing the parking brake at one end of the spindle, instead of the worm gear, for example, no force acts on the planetary gear during the parking maneuver. Instead, the parking brake acts directly on the spindle nut, which is designed as a brake piston. This reduces the play between the parking brake and the brake piston, so that after the parking brake is applied, the existing play does not lead to a reduction in the parking brake force. The force-free planetary gear also prevents creep, particularly with plastic planetary gears.

[0016] In another advantageous embodiment, the spindle drive unit is a ball screw. In a ball screw, balls are arranged between the spindle and the spindle nut, through which the axial force is transmitted. Thanks to the balls, a ball screw exhibits low friction despite the higher number of threads. This lower friction allows for a smaller electric motor. A ball screw also has the advantage of being suitable for higher loads.

[0017] According to a practical design, the second module variant has a longer spindle. In particular, the longer spindle has a longer engagement area with the spindle nut. This distributes the force across more threads, allowing the spindle drive unit to transmit a higher axial force. Furthermore, the spindle is extended to accommodate the planetary gear in the second module variant.

[0018] The invention also provides a motor vehicle having such an electromechanical brake. Such a motor vehicle has the advantages and properties described above.

[0019] Embodiments of the invention are illustrated in the drawing and explained in more detail in the following description. It shows: Fig. 1 Sectional view of an embodiment of a first module variant of the electromechanical brake, and Fig. 2 Sectional view of an embodiment of a second module variant of the electromechanical brake.

[0020] In Fig. Figure 1 shows a sectional view of an embodiment of a first module variant of the electromechanical brake 10. The electromechanical brake 10 according to the first module variant comprises a brake caliper housing 14, which is connected to a brake caliper 22 of the electromechanical brake 10 via connecting means 18. A control unit 26 and an electric motor 30 are also arranged on the brake caliper housing 14. The electric motor 30 can be controlled via the control unit 26.

[0021] A spindle drive unit 34 is arranged in the brake caliper housing 14, via which a pressure plate 42 arranged on a spindle nut 38 of the spindle drive unit 34 can be axially displaced. In the exemplary embodiment shown, the spindle nut 38 is thus also the brake piston of the electromechanical brake 10. A worm wheel 50 of a worm gear 54, which is driven by the electric motor 30, is arranged in a rotationally fixed manner on a spindle 46 of the spindle drive unit 34. The worm gear 50 is driven by the electric motor 30. The spindle 46 is rotatably mounted in the brake caliper housing 14 via an angular contact ball bearing 58. The angular contact ball bearing 58 bears against a retaining plate 62 introduced into the brake caliper housing 14, via which retaining plate 62 axial forces of the angular contact ball bearing 58 are absorbed. In the exemplary embodiment shown here, the spindle drive unit 34 is designed as a ball screw drive.

[0022] A parking brake 66 is arranged at one axial end of the spindle 46, by means of which the spindle 46 can be locked. The parking brake 66 is provided on the spindle 46 downstream of the worm gear 50.

[0023] Fig. 2 shows a sectional view of an embodiment of a second module variant of the electromechanical brake 10. This module variant differs from the one in Fig. 1 in that a planetary gear 70 is arranged between the angular contact ball bearing 58 and the worm gear 50, instead of the retaining plate 62. Using the second module variant, it is possible to apply a higher braking force. Both variants have the same electric motor 30. An inner diameter D of the brake caliper housing 14, as well as a diameter D S for the worm wheel 50, is the same for both module variants.

[0024] However, to accommodate the higher braking forces, a spindle drive unit 34 is provided in which the engaged threads between spindle 46 and spindle nut 38 are increased. Accordingly, spindle 46 and spindle nut 38 are longer than in the first module variant. The angular contact ball bearing 58 is selected in the same way so that it can accommodate a higher axial load.

[0025] The planetary gear 70 is formed from planetary gears 74 arranged on a planetary carrier 78, with the planetary gears 74 orbiting a central sun gear 82. The planetary carrier 78 is fixedly connected to the spindle 46, so that the spindle 46 is driven by the rotation of the planetary carrier 78. The planetary gears 74 and the sun gear 82 are surrounded by a ring gear 86. The planetary gears 74 mesh with this ring gear 86. In the illustrated embodiment, the sun gear 82 is hollow, so that the spindle 46 engages the sun gear 82.

[0026] In contrast to the first module variant, the worm gear 50 is not rigidly connected to the spindle 46. A bearing 90 is arranged between the spindle 46 and the worm gear 50, via which the worm gear 50 is rotatably mounted on the spindle 46. The worm gear 50 forms an axial extension 94 extending between the sun gear 82 and the spindle 46. The axial extension 94 is non-rotatably connected to the sun gear 82, so that the sun gear 82 is driven via the worm gear 50.

[0027] The planetary gear 70 allows for a higher braking force to be applied despite using the same electric motor 30. Except for the planetary gear 70, both module variants thus have comparable components, meaning both module variants can be manufactured on the same production line. Manufacturing both module variants is thus more cost-effective. 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 1 030 979 B1

[0003] DE 10 2018 211 443 A1

[0004] US 2019 / 0003535 A1

[0005]

Claims

[1] Electromechanical brake (10) for a motor vehicle, wherein the electromechanical brake (10) is of modular construction, and a first module variant comprises a brake calliper (22) and a brake calliper housing (14) connected to the brake calliper (22), in which a spindle drive unit (34) and a worm gear (54) operatively connected thereto are arranged, which are driven by an electric motor (30), wherein a force can be applied to a brake piston (38) for braking via the spindle drive unit (34), and wherein the second module variant, in addition to the first module variant, comprises a planetary gear (70) likewise arranged in the brake calliper housing (14) between the worm gear (54) and the spindle drive unit (34). [2] Electromechanical brake (10) according to claim 1, characterized by that a worm wheel (50) of the worm gear (54) has the same diameter (D S ). [3] Electromechanical brake (10) according to claim 1 or 2, characterized by that the electric motor (30) is the same for both module variants. [4] Electromechanical brake (10) according to one of the preceding claims, characterized by that the planet gears (74) are made of a plastic material. [5] Electromechanical brake (10) according to one of the preceding claims, characterized by that the planetary gear (70) has a hollow sun gear (82) over which a spindle (46) of the spindle drive unit (34) is passed. [6] Electromechanical brake (10) according to claim 5, characterized by that a parking brake (66) is arranged at one end of the spindle (46), by means of which the spindle (46) can be locked in a braked position. [7] Electromechanical brake (10) according to one of the preceding claims, characterized by that the spindle drive unit (34) is a ball screw drive. [8] Electromechanical brake (10) according to one of the preceding claims, characterized by that the second module variant has a longer spindle (46). [9] Motor vehicle comprising an electromechanical brake (10) according to one of the preceding claims.

Images