Actuator assembly of an electromechanical vehicle brake and method for mounting a brake piston in an actuator assembly

Abstract

An actuator assembly for an electromechanical vehicle brake is disclosed, comprising a brake piston (16) linearly displaceable along an axial direction (A) for applying a brake pad to a brake rotor, a brake caliper unit (12) in which a receptacle (18) with an inner circumferential surface (23) is formed, which forms a running surface (24) for the brake piston (16), and a retaining disc (26) arranged within the receptacle (18) and rotationally fixed to the brake caliper unit (12) on one side and to the brake piston (16) on the other. A method for mounting a brake piston (16) in an actuator assembly is also proposed.

Description

[0001] The invention relates to an actuator assembly of an electromechanical vehicle brake. The invention also relates to a method for mounting a brake piston in an actuator assembly.

[0002] Actuator assemblies for vehicle brakes typically have a linearly movable brake piston, which is guided in a brake caliper unit and serves to apply a brake pad to a brake rotor. For this purpose, the brake piston is moved, for example, by means of a spindle drive.

[0003] In order to fully translate a rotation of a spindle into a linear movement of the brake piston, the brake piston must be guided in the brake caliper unit in a way that prevents it from twisting.

[0004] In order to implement an anti-twist device, various solutions are known in the state of the art.

[0005] However, this often requires complex machining of the brake caliper unit using special tools, such as angle head tools, in order to machine internal surfaces for guidance in the axial direction.

[0006] Based on this, the object of the invention is to provide an actuator assembly of an electromechanical vehicle brake in which an anti-twist device for the brake piston can be implemented particularly easily.

[0007] The stated object is achieved according to the invention by an actuator assembly of an electromechanical vehicle brake, with a brake piston which is linearly displaceable along an axial direction and which serves to apply a brake pad to a brake rotor, a brake caliper unit in which a receptacle is formed with an inner circumferential surface which forms a running surface for the brake piston, and a retaining disc which is arranged within the receptacle and is coupled in a rotationally fixed manner on the one hand to the brake caliper unit and on the other hand to the brake piston.

[0008] The basic idea of ​​the invention is to secure the brake piston against rotation by means of the retaining disc, which is rotationally fixedly connected to both the brake caliper unit and the brake piston. Consequently, the brake piston is also rotationally fixedly connected to the brake caliper unit via the retaining disc.

[0009] The brake piston remains axially movable, allowing relative movement between the brake piston and the brake caliper unit, as well as between the brake piston and the retaining disc. Relative movement between the retaining disc and the brake caliper unit, however, is not possible, as the latter cannot be moved axially within the mount.

[0010] The retaining disc makes it particularly easy to implement an anti-twist device, as it's particularly simple to manufacture and machine. Inserting it into the brake caliper unit's mount during assembly also requires little effort.

[0011] According to one aspect, a coupling geometry can be formed between the retaining disc and the brake piston, which couples the retaining disc and the brake piston in a rotationally fixed manner and allows for relative displacement between the retaining disc and the brake piston in the axial direction. Accordingly, relative displacement between the retaining disc and the brake caliper unit is not provided. The coupling geometry allows the retaining disc and the brake piston to be coupled to each other in a rotationally fixed manner particularly easily and reliably.

[0012] The coupling geometry can be formed by at least one web projecting in the axial direction on the retaining disc and a groove provided on the brake piston into which the web projects, wherein the web merges integrally into a disc-shaped section of the retaining disc.

[0013] This is a particularly simple design of the coupling geometry.

[0014] The web on the retaining disc, which protrudes in the axial direction, can also be provided particularly easily due to the simple geometry and at the same time form a reliable and robust positive connection with the groove in the circumferential direction.

[0015] Furthermore, the groove provided on the brake piston can be located on the outer circumference of the brake piston. This is advantageous for manufacturing, as the groove is located in a particularly easily accessible location on the brake piston.

[0016] Furthermore, the retaining disc can have several axially protruding webs that are evenly arranged along the circumference of the retaining disc. Multiple webs can ensure that any forces that may be present are evenly distributed across several webs and evenly distributed into the disc-shaped section of the retaining disc.

[0017] Furthermore, the retaining disc can be pressed into the recess in the brake caliper unit. Additionally or alternatively, the recess can have a conical section in the area surrounding the retaining disc.

[0018] Pressing the retaining disc into the brake caliper unit's holder can be done particularly easily.

[0019] If the receptacle is provided with a conical section in the area surrounding the retaining disc, this makes it easier to press the retaining disc into the receptacle, since the conical section can only be introduced in the area of ​​the receptacle in which the retaining disc is to be fixed by pressing in.

[0020] On the other hand, this can ensure that only a part of the retaining disc is pressed in, such as mainly the disc-shaped section of the retaining disc and the webs only in pairs or not at all.

[0021] In addition, the retaining disc can have a shim section that defines the axial play in the actuator assembly. Thus, the retaining disc can ensure that the brake piston is positioned in a rotationally fixed manner relative to the brake caliper unit, and the axial play can also be adjusted via the shim section.

[0022] Furthermore, an axial bearing can be provided in the receptacle, which extends axially between the retaining disc and a spindle of a reciprocating spindle drive for the brake piston and is clamped between the two.

[0023] The axial bearing rests on the shim section of the retaining disc.

[0024] In order to be able to adjust the axial play of one of the axial bearings, a shim would be necessary anyway, so that the retaining disc itself does not form an additional component, but allows the axial play to be adjusted through the shim section and at the same time takes over the function of preventing the brake piston from rotating.

[0025] Furthermore, the section of the retaining disc can be designed as an annular disc section, and a drive shaft for the spindle can extend through the retaining disc. Thus, the annular disc section allows the drive shaft to pass through the retaining disc.

[0026] The object mentioned at the outset is also achieved by a method for mounting a brake piston in an actuator assembly according to the invention, comprising the steps: a) Mounting the retaining disc in the holder so that the retaining disc is coupled to the brake calliper unit in a rotationally fixed manner, and then inserting the brake piston into the holder so that the retaining disc is coupled to the brake piston in a rotationally fixed manner; or b) Placing the retaining disc onto an axial end of the brake piston so that the retaining disc is coupled to the brake piston in a rotationally fixed manner and inserting the brake piston with the retaining disc placed thereon into the holder, whereby the retaining disc forms a frictional connection with the holder of the brake calliper on its outer circumferential surface.

[0027] The brake piston can therefore be mounted in different ways.

[0028] It is either possible that the retaining disc alone is first coupled to the brake calliper unit in a rotationally fixed manner, for example by pressing it in and then inserting the brake piston into the holder so that the retaining disc and brake piston are coupled in a rotationally fixed manner.

[0029] Alternatively, the retaining disc can be positioned on the brake piston and then the brake piston can be inserted into the holder together, so that the retaining disc is pressed into the holder over the brake piston. This has the advantage that no additional special tools are required to hold and press in the retaining disc.

[0030] The additional benefits can be found in the paragraphs above.

[0031] The invention is described below with reference to an embodiment illustrated in the accompanying drawings, in which: - Fig. 1 a schematic representation of an actuator assembly according to the invention in a perspective view; - Fig. 2 the detail D of Fig. 1 as a section along plane II-II; - Fig. 3 the detail D of Fig. 1 as a perspective partial section in a further view; - Fig. 4 the representation from Fig. 2 without attachments; - Fig. 5a a retaining disc for the actuator assembly according to the invention in a perspective view without brake caliper unit; - Fig. 5b the retaining disc for the actuator assembly according to the invention in a further perspective view; and - Fig. 6 a brake piston for the actuator assembly according to the invention in a perspective view.

[0032] Fig. Figure 1 shows an actuator assembly 10 of an electromechanical vehicle brake (not shown in detail). The actuator assembly 10 comprises a brake caliper unit 12 with a space 14 in which a brake rotor and brake pads arranged on both sides of the brake rotor are located (not shown in the figures).

[0033] The brake pads can be pressed against the brake rotor by a brake piston 16 that can be moved linearly along an axial direction A, so that a braking force can be provided.

[0034] The brake piston 16 is received in a cylindrical receptacle 18 of the brake caliper unit 12 so as to be linearly displaceable in an axial direction A, which corresponds to the longitudinal direction of the brake piston 16.

[0035] Furthermore, a drive unit 20 is provided, which comprises a drive for moving the brake piston 16 along the axial direction A. This can be a spindle drive, in particular a recirculating ball screw drive, the spindle of which is located within the brake piston 16 and drives it axially.

[0036] The drive unit 20 serves to drive a spindle 21 of a ball screw drive 22 for the brake piston 16 (see in particular Fig. 2).

[0037] The receptacle is formed by an inner peripheral surface 23, wherein the inner peripheral surface 23 is precisely matched to the outer surface of the brake piston 16 so that it forms a running surface 24 for the brake piston 16.

[0038] A retaining disc 26 is arranged in the receptacle 18, which is coupled in a rotationally fixed manner on the one hand to the brake caliper unit 12 and on the other hand to the brake piston 16.

[0039] The rotationally fixed coupling between the retaining disc 26 and the brake caliper unit 12 is realized by pressing the retaining disc 26 into the receptacle 18. Thus, there is a frictional connection between an outer circumferential surface 27 of the retaining disc 26 and the receptacle 18 of the brake caliper unit 12.

[0040] The receptacle 18 of the brake calliper unit 12 has a conical section 28 in the area surrounding the retaining disc 26 (see in particular Fig. 4).

[0041] In addition, a coupling geometry 30 is formed between the retaining disc 26 and the brake piston 16.

[0042] The coupling geometry 30 allows the retaining disc 26 and the brake piston 16 to be positively coupled to one another in a rotationally fixed manner, so that the latter is secured against rotation about the axial direction A relative to the brake caliper unit 12. Furthermore, the coupling geometry 30 allows for a displacement between the retaining disc 26 and the brake piston 16, so that the brake pads can be applied against the brake rotor via the brake piston 16.

[0043] The coupling geometry 30 comprises two webs 32 projecting in the axial direction on the retaining disc 26 (see in particular Fig. 2, Fig. 3, Fig. 5A, B).

[0044] However, it is also conceivable that only one web 32 is provided on the holding disc 26 or even more than two webs 32, wherein these multiple webs could be arranged evenly along the circumference of the holding disc 26.

[0045] The webs 32 projecting in the axial direction merge integrally into the disc-shaped section 34 of the retaining disc 26 and extend from the end face of the disc-shaped section in the region of the outer circumference of the disc-shaped section 34.

[0046] The webs 32 have a ring-segment-shaped cross-section, with opposite side surfaces 35 of the ring-segment-shaped cross-section of a web running parallel to one another.

[0047] Both webs 32 of the retaining disc 26 engage in grooves 36 assigned to them, which are provided on the outer circumference of the brake piston 16 and which are also part of the coupling geometry 30 (see in particular Fig. 2, Fig. 3 and Fig. 6).

[0048] The grooves 36 have mutually facing side surfaces 38, each of which contacts an opposite side surface 35, so that the brake piston 16 is guided radially along the side surfaces 35, 38 during a displacement in the axial direction.

[0049] In addition, the retaining disc 26 has a shim section 40.

[0050] The shim portion 40 determines the axial positioning of an axial bearing 42, which is arranged within the receptacle 18. Thus, the shim portion 40 determines the axial play in the actuator assembly 10.

[0051] The axial bearing 42 is arranged and clamped axially between the retaining disc 26, more precisely between the compensating disc section 40 and the spindle 21 of the ball screw drive 22 for the brake piston 16.

[0052] Thus, the thickness of the shim section 40 has a direct influence on the axial clearance. The shim section 40 is an annular, inner section of the end face that protrudes axially from the remaining part of the end face of the disc-shaped section 34.

[0053] Furthermore, a drive shaft 44 is provided which extends through the annular disc-shaped section 34 of the holding disc 26 (see in particular Fig. 3).

[0054] In the following, the method for mounting the brake piston 16 in the previously explained actuator assembly 10 will be explained with reference to the figures.

[0055] The brake piston 16 can be mounted according to two different options.

[0056] According to the first option, the retaining disc 26 can first be pressed into the receptacle 18.

[0057] This creates a frictional connection between the retaining disc 26 and the brake caliper unit 12, so that they are coupled together in a rotationally fixed manner.

[0058] The brake piston 16 can then be inserted into the receptacle 18 so that the retaining discs are coupled together in a rotationally fixed manner via the coupling geometry 30 formed by webs 32 and grooves 36.

[0059] According to the second option, however, it is also possible that the retaining disc 26 is first pushed onto the axial end of the brake piston 16.

[0060] This is done by inserting the webs 32 of the retaining disc 26 into the grooves 36 of the brake piston 16 so that the coupling geometry 30 is engaged and the retaining disc 26 is coupled to the brake piston 16 in a rotationally fixed manner.

[0061] Thus, the brake piston 16 together with the attached retaining disc 26 can be pushed into the receptacle 18, wherein the retaining disc is pressed into the receptacle 18 or at least into the conical section 28 of the receptacle 18, so that there is a frictional connection between the outer circumferential surface of the retaining disc 26 and the receptacle 18 of the brake caliper unit 12.

Claims

[1] Actuator assembly of an electromechanical vehicle brake, with a brake piston (16) which is linearly displaceable along an axial direction (A) and serves to apply a brake pad to a brake rotor, a brake calliper unit (12) in which a receptacle (18) with an inner circumferential surface (23) is formed, which forms a running surface (24) for the brake piston (16), and a retaining disc (26) which is arranged within the receptacle (18) and is coupled in a rotationally fixed manner on the one hand to the brake calliper unit (12) and on the other hand to the brake piston (16). [2] Actuator assembly according to claim 1, characterized by that a coupling geometry (30) is formed between the holding disc (26) and the brake piston (16), which coupling geometry couples the holding disc (26) and the brake piston (16) to one another in a rotationally fixed manner and allows a relative displacement between the holding disc (26) and the brake piston (16) in the axial direction. [3] Actuator assembly according to claim 2, characterized bythat the coupling geometry (30) is formed by at least one web (32) projecting in the axial direction on the holding disc (26) and a groove (36) provided on the brake piston (16) into which the web (32) projects, wherein the web (32) merges integrally into a disc-shaped section (34) of the holding disc (26). [4] Actuator assembly according to claim 3, characterized by that the groove (36) provided on the brake piston (16) is provided on the outer circumference of the brake piston (16). [5] Actuator assembly according to claim 3 or 4, characterized by that the retaining disc (26) has a plurality of webs (32) projecting in the axial direction, which are arranged uniformly along the circumference of the retaining disc (26). [6] Actuator assembly according to one of claims 3 to 5, characterized by that a drive shaft (44) for the spindle (21) extends through the disc-shaped section (34) of the holding disc (26). [7] Actuator assembly according to one of the preceding claims, characterized by that the retaining disc (26) is pressed into the receptacle (18) in the brake calliper unit (12) and / or that the receptacle (18) has a conical section (28) in the area surrounding the retaining disc (26). [8] Actuator assembly according to one of the preceding claims, characterized by that the retaining disc (26) has a shim section (40) by which the axial play in the actuator assembly is determined. [9] Actuator assembly according to one of the preceding claims, characterized by that an axial bearing (42) is provided in the receptacle (18), which extends axially between the retaining disc (26) and a spindle (21) of a ball screw drive (22) for the brake piston (16) and is clamped between the two. [10] Method for mounting a brake piston (16) in an actuator assembly (10) according to one of the preceding claims, comprising the steps: a) mounting the retaining disc (26) in the receptacle (18) so that the retaining disc (26) is coupled to the brake calliper unit (12) in a rotationally fixed manner, and then inserting the brake piston (16) into the receptacle (18) so that the retaining disc (26) is coupled to the brake piston (16) in a rotationally fixed manner; or b) Placing the retaining disc (26) onto an axial end of the brake piston (16) (16) so that the retaining disc (26) is coupled to the brake piston (16) in a rotationally fixed manner and inserting the brake piston (16) with the retaining disc (26) placed thereon into the receptacle (18), the retaining disc (26) forming a frictional connection with the receptacle (18) of the brake calliper on its outer circumferential surface.

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