Actuator assembly

Abstract

The invention relates to an actuator assembly. An actuator assembly (12) for an electromechanical vehicle brake (10) has a brake caliper (14), in which there is an intermediate space (16) for receiving a brake rotor (18); the invention relates to a brake device for a motor vehicle, comprising a brake rotor, a ball screw drive having an actuating slide (24) for applying a brake pad (20) to the brake rotor and an electric drive spindle (26) for an axial movement of the actuating slide, the actuating slide being displaceable by an axial displacement between an extended position and a retracted position. The spindle has a spindle shaft (28) and an output sleeve (30), which is separate from the spindle shaft and is arranged on the spindle shaft in a tooth-shaped and torque-transmitting engagement. A threaded raceway (32) is formed on the outer peripheral surface of the output sleeve (30), and an opposing raceway (34) for balls is formed on the inner peripheral surface of the actuation slider (24).

Description

Technical Field

[0001] The present invention relates to an actuator assembly, and more particularly to an electromechanical vehicle brake. Background Art

[0002] The actuator assembly in a vehicle brake is used to apply the brake pad to the brake rotor. To this end, the actuator assembly usually has a spindle drive with an actuating slide and an electric drive spindle for axial movement of the actuating slide, wherein the axial feed force is transmitted from the actuating slide to the brake pad for applying the brake pad to the brake rotor.

[0003] When the vehicle brakes are actuated, high lateral forces act on the brake pads and the actuation slider, thereby generating a bending moment in the actuator assembly. The bending moment can cause a deflection of the brake caliper. In this case, some components of the actuator assembly (such as the spindle) are aligned with the brake caliper, while other components (such as the actuation slider) are aligned with the brake rotor. This results in large radial forces in the actuator assembly, which can cause increased wear over long travels.

[0004] In the known actuator assembly, the spherical bearing plate is arranged on the bearing surface of the spindle facing away from the brake pad. However, due to the relatively long distance from the brake pad, the transverse forces in the actuator assembly are only insufficiently eliminated. Summary of the invention

[0005] It is therefore an object of the present invention to specify a solution for avoiding large radial forces in an actuator assembly of a vehicle brake.

[0006] The invention is achieved by an actuator assembly, in particular for an electromechanical vehicle brake, having a brake caliper in which there is an intermediate space for receiving a brake rotor, an actuating slide for applying a brake pad to the brake rotor and a ball screw drive of an electric drive spindle for axial displacement of the actuating slide, wherein the actuating slide can be moved by an axial displacement between an extended position and a retracted position. The spindle has a spindle rod and an output sleeve, which is separate from the spindle rod and is arranged on the spindle rod in a toothed and torque-transmitting manner, wherein a threaded raceway is formed on the outer peripheral surface of the output sleeve and a counter raceway for the balls is formed on the inner peripheral surface of the actuating slide. The output sleeve is fixed to the spindle rod, in particular axially and rotationally fixed.

[0007] Since the output sleeve is manufactured separately from the spindle, a relative movement between the spindle and the output sleeve is possible in order to avoid excessive radial forces when the brake caliper is deformed. In particular, transverse forces and bending moments are largely avoided in the actuator assembly, so that less wear occurs and the service life of the actuator assembly is thus extended. Since transverse forces are avoided, the axial bearings present in the actuator assembly are also lightened in load. Power losses due to friction are also reduced, thereby optimizing the efficiency of the actuator assembly.

[0008] In a vehicle brake with an actuator assembly according to the invention, the pressure distribution on the brake pad is also particularly uniform, whereby there is uniform wear when viewed on the surface. In other words, oblique wear is avoided.

[0009] The two-part manufacturing also allows a modular system to provide different output sleeves, which are connected to the same spindle rod, depending on the load requirements. Cost savings in the production of different actuator assemblies can thereby be achieved.

[0010] Preferably, in the region of the output sleeve, the spindle rod has an external toothing and the output sleeve has an internal toothing, wherein the external toothing of the spindle rod has a crown-shaped configuration so that the output sleeve and the spindle rod can be tilted relative to each other. The crown-shaped external toothing makes it possible to produce a greater angular offset between the spindle rod and the output sleeve, so that transverse forces and bending moments can be dissipated in a more effective manner.

[0011] According to one embodiment, flexible rings are arranged on both sides of the output sleeve adjacent to the output sleeve. The flexible rings allow relative movement of the output sleeve with respect to the spindle while ensuring a defined axial position of the output sleeve on the spindle. Thus, it is ensured that the torque-transmitting engagement of the output sleeve with the spindle is maintained.

[0012] The flexible ring is fixed to the spindle rod, for example, in a positively fitting manner.Thus, during assembly, the flexible ring can be easily mounted in a defined position, so that the axial position of the output sleeve is also defined.

[0013] According to one embodiment, the flexible ring is axially held in a form-fitting manner in a respectively assigned peripheral recess and / or by means of a locking ring and can be elastically compressed when the spindle rod is tilted relative to the output sleeve. Thus, the flexible ring can be mounted in a simple manner. Since the flexible ring is elastically compressed when the spindle rod is tilted towards the output sleeve, the flexible ring does not impair the freedom of movement of the output sleeve.

[0014] The output sleeve is clamped axially without any play between the rings. The axial position of the output sleeve is therefore particularly precisely defined.

[0015] The flexible ring can also be used to compensate for tolerances. In particular, it is conceivable to produce the flexible ring with an oversize, wherein during assembly the flexible ring can adapt to the shape of the surrounding component because the flexible ring deforms elastically accordingly.

[0016] The output sleeve can be axially supported on the brake caliper or on a housing fixed to the brake caliper via an axial bearing, wherein an intermediate element is arranged between the axial bearing and the output sleeve, the intermediate element having a spherical surface on its side facing the output sleeve, on which the output sleeve rests. The output sleeve has a spherical surface of corresponding shape. An improved load distribution of the forces acting axially on the axial bearing is achieved by means of such an intermediate element.

[0017] The center point of the spherical surface is preferably located in the intermediate space for receiving the brake rotor.Therefore, a particularly advantageous curvature of the spherical surface is particularly achieved, so that the intermediate element does not hinder the tilting of the output sleeve relative to the spindle rod.

[0018] The spindle rod is radially supported on the brake caliper or on a housing fixed to the brake caliper, for example, by means of a sliding bearing. In the simplest case, the sliding bearing can be simply and cost-effectively manufactured through a hole in the brake caliper.

[0019] According to one embodiment, the actuator assembly comprises an electric motor, which is drivingly coupled to the spindle via a gear unit in order to rotate the spindle for moving the actuation slide between the retracted position and the extended position. The actuator assembly is thus an electromechanical actuator assembly. A force large enough to apply the brake pad to the brake rotor via the actuation slide can be generated by means of the electric motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Further advantages and features of the present invention will be found in the following description and in the accompanying drawings with reference to which:

[0021] Figure 1 A vehicle brake having an actuator assembly according to the invention is shown;

[0022] Figure 2 Shows Figure 1 A schematic diagram of an actuator assembly;

[0023] Figure 3 A spindle rod of a spindle drive is shown;

[0024] Figure 4 The output sleeve of the spindle drive is shown;

[0025] Figure 5 A main shaft rod with a positioning element is shown; and

[0026] Figure 6 The actuator assembly is shown in the region of the output sleeve of the spindle drive. DETAILED DESCRIPTION

[0027] Figure 1 A vehicle brake 10 is shown having an actuator assembly 12. The vehicle brake 10 is an electromechanically actuatable brake.

[0028] The actuator assembly 12 comprises a brake caliper 14 in which an intermediate space 16 is formed for a brake rotor 18 (see Figure 2 ).

[0029] A brake pad 20 , which can be applied to the brake rotor 18 , is arranged in the intermediate space.

[0030] Additionally, the actuator assembly 12 includes a spindle drive 22 , which in the exemplary embodiment is a ball screw drive.

[0031] The spindle drive 22 comprises an actuating slide 24 for applying the brake pad 20 to the brake rotor 18 and an electric drive spindle 26 for axial movement of the actuating slide 24 , wherein the actuating slide 24 can be moved by an axial displacement between an extended position and a retracted position.

[0032] In particular, the actuation slide 24 represents a brake piston.

[0033] The main shaft 26 is divided into two and comprises a main shaft rod 28 and an output sleeve 30 which is separate from the main shaft rod 28 and is arranged on the main shaft rod 28 in a toothed and torque-transmitting engagement.

[0034] A thread raceway 32 is formed on the outer peripheral surface of the output sleeve 30, and an opposing raceway 34 for balls is formed on the inner peripheral surface of the actuating slide 24. Thus, the actuating slide 24 represents a spindle nut of the spindle drive 22.

[0035] The actuating slide 24 is guided in the brake caliper 14 in a rotationally fixed manner.

[0036] The actuator assembly 12 also includes an electric motor which is not visible in the drawings.

[0037] The electric motor is drivingly coupled to the spindle 28 via a gear unit 36 ​​in order to rotate the spindle 28 for moving the actuation slide 24 between the retracted position and the extended position.

[0038] Due to the torque-transmitting engagement with the spindle 28 , the output sleeve 30 rotates together therewith, whereby the balls circulate in the thread races, thus causing an axial displacement of the actuation slide 24 .

[0039] The spindle rod 28 is radially supported on the brake caliper 14 by means of a sliding bearing 38. In the exemplary embodiment, the sliding bearing 38 is formed as a cylindrical recess in the brake caliper 14. However, it is also conceivable to provide a bearing bushing in the brake caliper 14.

[0040] The output sleeve 30 is axially supported on the brake caliper 14 via an axial bearing 40. The axial bearing 40 is, for example, a needle bearing.

[0041] An intermediate element 42 is arranged between the axial bearing 40 and the output sleeve 30, and on its side facing the output sleeve 30 the intermediate element has a spherical surface 44, on which the output sleeve 30 rests. Figure 1 As shown, the output sleeve 30 has a bearing surface shaped in a complementary manner to the surface 44 .

[0042] The center point of the spherical surface 44 is located in the intermediate space 16 for receiving the brake rotor 18 .

[0043] In an alternative exemplary embodiment, which is not shown for the sake of simplicity, the plain bearing 38 and the axial bearing 40 may be configured to be fixed to the brake caliper 14 or supported thereon in a housing.

[0044] Since the spindle 26 is produced in two parts, a certain relative movement is possible between the spindle rod 28 and the output sleeve 30. More specifically, the spindle rod 28 and the output sleeve 30 may be tilted relative to each other.

[0045] This relative movement can avoid lateral forces and bending moments in the actuator assembly 12. Figure 2 This is explained.

[0046] Figure 2 The vehicle brake 10 is schematically shown in an actuated state, wherein the actuation slide 24 pushes the brake pad 20 against the brake rotor 18 , so that an axial feed force acts in the vehicle brake 10 .

[0047] The axial feed force causes lateral forces and bending moments in the actuator assembly 12, so that a certain deformation of the brake caliper 14 occurs. For a clearer explanation, the deformation of the brake caliper 14 is Figure 2 Typically, the brake caliper 14 deflects up to 1°.

[0048] In the exemplary embodiment, a deflection of 0.9° is achieved with a feed force of 65 kN.

[0049] However, such a deflection is disadvantageous since it can lead to increased wear due to the bending moments that occur.

[0050] This disadvantageous effect is avoided by the separation of the spindle 28 and the output sleeve 30 according to the invention.

[0051] This is accomplished by aligning the spindle rod 28 with the brake caliper 14 , optionally in conjunction with the bearing bushing, while aligning the output sleeve 30 with the brake rotor 18 , in conjunction with the actuation slide 24 .

[0052] The gear unit 36 ​​is also aligned with the brake caliper 14 , so that deformations of the brake caliper 14 are not transferred into the gear unit 36 ​​.

[0053] Thus, the components of the actuator assembly 12 may accommodate deformation of the brake caliper 14 without incurring increased lateral forces.

[0054] The possibility of the main shaft 28 and the output sleeve 30 being tilted relative to each other is provided by Figure 3 and Figure 4 The geometry shown in is provided.

[0055] like Figure 3 As shown, the spindle 28 has an external toothing 46 in the region of the output sleeve 30. The output sleeve 30 has an internal toothing 47 (see Figure 4 ).

[0056] The external teeth 46 of the spindle 28 have a crown-like configuration, so that the output sleeve 30 and the spindle 28 can be tilted relative to each other.

[0057] The internal teeth 47 have a straight configuration.

[0058] Radial and axial offsets between the main shaft 28 and the output sleeve 30 can be compensated by the external teeth 46 having a crown-like configuration.

[0059] Another toothing 49 on the axial end of the spindle rod 28 is used for coupling to the gear unit 36 ​​.

[0060] The axial positioning of the output sleeve 30 on the spindle 28 is performed by means of two flexible rings 48 which adjoin the output sleeve 30 on both sides thereof. In practice, the output sleeve 30 is particularly axially clamped, wherein between the rings 48 there is no play.

[0061] The two flexible rings 48 are fixed to the spindle rod 28 in a form-fitting manner.

[0062] One of the two rings 48 is arranged in an associated peripheral recess 50 (see Figure 4 ).

[0063] The second ring 48 is axially retained by a locking ring 52, such as Figure 5 and Figure 6 as shown in .

[0064] When the spindle 28 is tilted relative to the output sleeve 30 , the flexible ring 48 is elastically compressed.

[0065] like Figure 6 As can be seen in the figure, the recess 54 in which the flexible ring 48 is arranged is located on the front face in the output sleeve 30, so that the flexible ring 48 is arranged to overlap axially with the output sleeve 30 and does not protrude beyond the output sleeve 30. In this way, a compact design is achieved. Specifically, the length of the main shaft 26 can be reduced thereby.

Claims

1. An actuator assembly (12), in particular for an electromechanical vehicle brake (10), comprising: A brake caliper (14) in which there is an intermediate space (16) for receiving a brake rotor (18), A ball screw drive having an actuating slide (24) for applying a brake pad (20) to the brake rotor (18) and an electric drive spindle (26) for axial movement of the actuating slide (24), wherein the actuating slide (24) is movable by an axial displacement between an extended position and a retracted position, The spindle (26) has a spindle rod (28) and an output sleeve (30), which is separate from the spindle rod (28) and is arranged on the spindle rod (28) in a toothed and torque-transmitting manner, A threaded raceway (32) is formed on the outer peripheral surface of the output sleeve (30), and an opposing raceway (34) for balls is formed on the inner peripheral surface of the actuating slider (24).

2. The actuator assembly (12) according to claim 1, wherein: In the region of the output sleeve (30), the spindle rod (28) has external teeth (46) and the output sleeve (30) has internal teeth (47), wherein the external teeth (46) of the spindle rod (28) have a crown-like configuration, so that the output sleeve (30) and the spindle rod (28) can be tilted relative to each other.

3. An actuator assembly (12) according to any one of the preceding claims, wherein: Flexible rings (48) are arranged on both sides of the output sleeve (30) and are adjacent to the output sleeve (30).

4. The actuator assembly (12) according to claim 3, wherein: The flexible ring (48) is fixed to the spindle rod (28) in a form-fitting manner.

5. The actuator assembly (12) of claim 4, wherein: The flexible ring (48) is axially held in a form-fitting manner in a correspondingly assigned peripheral recess (50) and / or is axially held by means of a locking ring (52) and can be elastically compressed when the spindle rod (28) is tilted relative to the output sleeve (30).

6. An actuator assembly (12) according to any one of claims 3 to 5, wherein: The output sleeve (30) is axially clamped with no gaps between the rings.

7. An actuator assembly (12) according to any one of the preceding claims, wherein: The output sleeve (30) is axially supported on the brake caliper (14) or on a housing fixed to the brake caliper (14) via an axial bearing (40), wherein an intermediate element (42) is arranged between the axial bearing (40) and the output sleeve (30), and the intermediate element has a spherical surface (44) on its side facing the output sleeve (30), and the output sleeve (30) is supported on the spherical surface.

8. The actuator assembly (12) of claim 7, wherein: The center point of the spherical surface (44) is located in the intermediate space (16) for receiving the brake rotor (18).

9. An actuator assembly (12) according to any one of the preceding claims, wherein: The spindle rod (28) is radially supported on the brake caliper (14) or on a housing fixed to the brake caliper (14) by means of a sliding bearing (38).

10. An actuator assembly (12) according to any one of the preceding claims, wherein: The actuator assembly (12) includes an electric motor drivingly coupled to the spindle (28) via a gear unit (36) to rotate the spindle (28) for moving the actuation slide (24) between the retracted position and the extended position.

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