Electromechanical brake with anti-rotation device

Abstract

The invention relates to an electromechanical brake (10) for a motor vehicle. The electromechanical brake (10) comprises an electric motor (18) which rotates a spindle drive unit (30) arranged in a brake caliper housing (14), so that a brake actuator (50) can be displaced in an axial direction (46) of the brake caliper housing (14) to apply a braking force. An anti-rotation device (54) is formed between the brake caliper housing (14) and the spindle drive unit (30), which prevents relative rotation of a spindle nut (42) of the spindle drive unit (30) to the brake caliper housing (14). The anti-rotation device (54) is formed by at least one longitudinal groove (58) formed on the spindle nut (42), and at least one web (62) engaging in the longitudinal groove (58), wherein the web (62) is formed by at least one component separate from the brake caliper housing (14), which is fastened in the brake caliper housing (14).

Description

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

[0002] The service brake is typically a brake system that uses brake fluid to press a brake piston and brake pad against a brake disc to slow the vehicle. With the increasing electrification of vehicle components, the service brake is also being developed as an electromechanical brake, thus eliminating the need for brake fluid and the associated complex valve and line system. Such an electromechanical brake could also significantly reduce maintenance requirements.

[0003] German patent application DE 10 2013 005 744 B4 describes an electromechanically actuated parking brake. The parking brake comprises a spindle drive unit with a spindle and a spindle nut. A spur gear is formed at one axial end of the spindle and is driven by a worm gear, allowing the spindle nut to move axially. The spindle nut is connected to a brake piston, thus preventing rotation of the spindle nut.

[0004] EP 0 729 871 B1 describes an electrically actuated parking brake for a disc brake. The brake comprises a worm gear driven by an electric motor, which meshes with a worm wheel. The brake also includes a spindle drive unit with a spindle and a spindle nut. The worm wheel is located at one end of the spindle, so that the spindle is driven rotationally. The spindle drives a spindle nut, which is connected to a brake piston via an anti-rotation ring. An axial movement of the spindle nut allows the brake piston to be moved axially for braking.

[0005] The object underlying the invention is to provide an electromechanical brake for a motor vehicle that is simpler and more economical to manufacture.

[0006] The problem is solved by an electromechanical brake according to claim 1. Preferred embodiments are set forth in the dependent claims. Disclosure of the invention

[0007] The invention provides an electromechanical brake for a motor vehicle. The electromechanical brake comprises an electric motor which rotates a spindle drive unit arranged in a brake caliper housing, such that a brake actuator is displaceable in an axial direction of the brake caliper housing for applying a braking force. An anti-rotation device is formed between the brake caliper housing and the spindle drive unit, which prevents relative rotation of a spindle nut of the spindle drive unit with respect to the brake caliper housing. The anti-rotation device is formed by at least one longitudinal groove formed on the spindle nut and at least one web engaging in the longitudinal groove. The web is formed by at least one component separate from the brake caliper housing, which is fixed in the brake caliper housing.

[0008] A spindle drive unit is understood to be a unit comprising at least one spindle and a spindle nut, which interact with each other. The spindle can be in direct contact with the spindle nut, or it can interact with it via balls. Accordingly, a spindle drive unit includes both a ball screw drive and a spindle drive without balls. A brake adjuster is understood to be a component connected to the spindle nut that establishes a connection to a brake pad. The brake pad can be adjusted via this brake adjuster.

[0009] Typically, the spindle nut is manufactured using a machining process. To incorporate anti-rotation lugs on one of the spindle nut's outer surfaces, a blank with an outer diameter matching the lugs' dimensions is required. Except for the anti-rotation lugs, the blank is machined to the outer diameter of the spindle nut. This process is time-consuming and generates a significant amount of waste material in the form of chips. By forming the spindle nut with a longitudinal groove, a blank with the same outer diameter as the spindle nut can be used. Only the longitudinal grooves need to be machined. Therefore, forming such longitudinal grooves requires less time and produces less waste material, making this method of manufacturing the spindle nut more economical.

[0010] The anti-rotation lugs of the spindle nut typically engage in a corresponding longitudinal groove in the brake caliper housing. Because the component forming the anti-rotation lug is separate from the brake caliper housing, post-processing of the brake caliper housing is unnecessary. The brake caliper housing thus forms neither an anti-rotation lug nor a longitudinal groove. This allows for more economical manufacturing of the brake caliper housing. The invention therefore enables an electromechanical brake that is simpler and more economical to manufacture.

[0011] In a preferred embodiment of the invention, the bridge is formed by an annular disc. An annular disc is a simple component that can be manufactured economically. Due to its annular design, the disc can be mounted in the brake caliper housing in a space-saving manner.

[0012] In a further preferred embodiment of the invention, the disc is designed as a stamped part. Accordingly, the disc is manufactured by means of a stamping process. Such a process has the advantage that, unlike machining, it is time-efficient and requires little labor. A disc manufactured in this way can therefore be provided simply, economically, and in large quantities.

[0013] Preferably, the bridge is formed by at least one pin which is fixed in the brake caliper housing. Such a pin can be manufactured from a round raw material by a cutting step. Accordingly, a bridge designed as a pin can also be provided economically, thus reducing the manufacturing costs for the electromechanical brake.

[0014] In a further advantageous embodiment, the brake caliper housing has at least one radial bore on its outer surface through which the pin can be inserted from the outside. Mounting the pin from the outside of the brake caliper housing has the advantage that the internal surface of the brake caliper housing does not need to be reworked to accommodate such a pin during the assembly process. Such a pin can therefore also be provided after the spindle drive unit has been installed. The external bores can be easily and automatically created using a drilling process.

[0015] Advantageously, the pin is secured in the bore via an adhesive bond. Securing the pin in the bore with an adhesive has the advantage that it can be fastened without any mechanical modification of the pin or the brake caliper housing. However, such an adhesive bond is simply not economical to implement.

[0016] In another advantageous embodiment, the pin is secured in the bore via a screw connection. Unlike an adhesive connection, a screw connection has the advantage that the pin can be easily removed. This allows the pin to be replaced in case of a defect.

[0017] In a practical design, the pin is pressed into the bore. Unlike an adhesive bond, a pressed-in pin has the advantage that it will not loosen due to environmental influences or over time. Accordingly, a pressed-in pin ensures that the electromechanical brake remains securely fixed in the caliper housing for its entire service life. Furthermore, pressing in the pin can also be accomplished in a simple process step.

[0018] According to another practical embodiment, the surfaces of the web that interact with the longitudinal groove are post-treated. This surface treatment provides improved sliding contact between the web and the longitudinal groove. Alternatively or additionally, the web can also be coated with a friction-reducing surface.

[0019] The invention further specifies a motor vehicle which has such an electromechanical brake. The advantages and properties described above are achieved with such a motor vehicle.

[0020] Exemplary embodiments of the invention are shown in the drawing and explained in more detail in the following description. It shows: Fig. 1 Electromechanical brake according to an embodiment of the invention, Fig. 2 Sectional view of the spindle nut with the pins, Fig. 3 Electromechanical brake according to a further embodiment of the invention, and Fig. 4 Sectional view of the spindle nut with the washer.

[0021] In Fig. Figure 1 shows an electromechanical brake 10 according to an embodiment of the invention. The electromechanical brake 10 comprises an electric motor 18 attached to a brake caliper housing 14 of the electromechanical brake 10. The electric motor 18 is controlled via a control unit 22, which is also attached to the brake caliper housing 14. A worm gear 34 is attached to a spindle 26 of a spindle drive unit 30 arranged in the brake caliper housing 14, which in the illustrated embodiment is designed as a ball screw drive. This worm gear 34 interacts with a worm (not shown) driven by the electric motor 18, so that the spindle 26 is driven rotationally.

[0022] The spindle 26 is mounted to the brake caliper housing 14 via a bearing 38. Rotation of the spindle 26 causes a spindle nut 42 surrounding the spindle 26 to be displaceable in an axial direction 46. A brake adjuster 50 is arranged at one axial end of the spindle nut 42, through which a braking force can be applied. To prevent rotation of the spindle nut 42 relative to the brake caliper housing 14, an anti-rotation device 54 is provided. The anti-rotation device 54 is formed by two longitudinal grooves 58 formed on the spindle nut 42, which interact with several webs 62. The webs 62 are formed by pins arranged in bores 66 extending radially to the spindle drive unit 30.

[0023] The pins 62 are accordingly designed as separate components from the brake caliper housing 14, which are fastened in the bores 66. In the embodiment shown here, two different fastening options for the pins 62 are illustrated. On one side of the electric motor 18, the pins 62 can be glued in or pressed into the brake caliper housing 14. In contrast, on one side of the control unit 22, the pins 62 are screwed in via a thread 70. A sectional view of the spindle nut 42 with the pins 62 is shown in Fig. Figure 2 shows how the pins 62 engage in the longitudinal groove 58, thus blocking any relative rotation of the spindle nut 42 with respect to the brake caliper housing 14. A surface 74 of the pins 62 slides in the longitudinal groove 58 when the spindle nut 42 is axially displaced.

[0024] Fig. Figure 3 shows the electromechanical brake 10 according to a further embodiment of the invention. This embodiment differs from the one in Figure 3 in that it ... Fig. In the embodiment shown in Figure 1, the webs are formed by an annular disc 78 instead of pins 62. The disc 78 is arranged in the brake caliper housing 14 and is fixedly connected to it. The disc 78 can be connected to the brake caliper housing 14, for example, by bonding, screwing, or welding.

[0025] In Fig.Figure 4 shows a sectional view of the spindle nut 42 with the washer 78. This figure shows that the washer 78 forms two webs 62 which extend radially inwards. These webs 62 engage in the longitudinal grooves 58 of the spindle nut 42. To ensure good sliding contact between the longitudinal groove 58 and the webs 62, the contacting surface 74 of the webs 62 in the longitudinal grooves 58 is machined. QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] DE 10 2013 005 744 B4

[0003] EP 0 729 871 B1

[0004]

Claims

[1] Electromechanical brake (10) for a motor vehicle, comprising an electric motor (18) which rotaryally drives a spindle drive unit (30) arranged in a brake caliper housing (14), so that a brake actuator (50) is displaceable in an axial direction (46) of the brake caliper housing (14) for applying a braking force, wherein an anti-rotation device (54) is formed between the brake caliper housing (14) and the spindle drive unit (30), by means of which a relative rotation of a spindle nut (42) of the spindle drive unit (30) to the brake caliper housing (14) is blocked, characterized by , that the anti-rotation device (54) is formed by at least one longitudinal groove (58) formed on the spindle nut (42), and at least one web (62) engaging in the longitudinal groove (58), wherein the web (62) is formed by at least one component separate from the brake caliper housing (14), which is fastened in the brake caliper housing (14). [2] Electromechanical brake (10) according to claim 1, characterized by , that the bridge (62) is formed by an annular disk (78). [3] Electromechanical brake (10) according to claim 2, characterized by , that the disc (78) is designed as a stamped part. [4] Electromechanical brake (10) according to claim 1, characterized by , that the bridge (62) is formed by at least one pin which is fixed in the brake caliper housing (14). [5] Electromechanical brake (10) according to claim 4, characterized by , that the brake caliper housing (14) has at least one radial bore (66) on the outside, through which the pin (62) can be inserted from the outside. [6] Electromechanical brake (10) according to claim 5, characterized by that the pin (62) is fixed in the bore (66) via an adhesive bond. [7] Electromechanical brake (10) according to claim 5, characterized by that the pin (62) is fastened in the bore (66) via a screw connection. [8] Electromechanical brake (10) according to claim 5, characterized by , that the pin (62) is pressed into the bore (66). [9] Electromechanical brake (10) according to any one of claims 2 to 8, characterized by , that the surfaces (74) of the web (62) interacting with the longitudinal groove (58) are reworked. [10] Motor vehicle comprising an electromechanical brake (10) according to any of the preceding claims.

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