Brake actuator and vehicle brake

Abstract

The invention relates to a brake actuator and a vehicle brake. The brake actuator (12) has an electric motor (32) and a blocking module (36). The blocking module (36) comprises a blocking rod (40) and a blocking actuator (42), in which blocking teeth (44) are formed on the blocking rod (40), in the locking position of the blocking rod, the blocking teeth engage with a gear wheel coupled to the output shaft (38) of the motor. The blocking tooth (44) has a blocking geometry (61) on one tooth flank (60) and a lifting geometry (63) on the opposite tooth flank (62), said geometries (61, 63) being configured such that: upon rotation of the electric motor (32) in a first direction enhancing the braking force, the blocking lever (40) is lifted against the spring force by rotation of the electric motor (32) in order to disengage from the gear; and rotation of the electric motor (32) in the opposite direction in which the braking force is released is blocked.

Description

Technical Field

[0001] The invention relates to a brake actuator, in particular a brake actuator for an electromechanical vehicle brake, and to an electromechanical vehicle brake. Background Art

[0002] A brake actuator in a vehicle brake is used to support a brake pad on a brake rotor. For this purpose, the brake actuator usually has an electric motor, which is coupled to an actuating slide for driving via a gearbox unit and a spindle transmission, and the actuating slide for supporting the brake pad on the brake rotor can be selectively displaced between a retracted position and a deployed position. In order to support the brake pad on the brake rotor, an axial actuating force is transmitted from the actuating slide to the brake pad.

[0003] In addition to being used as a service brake, the electromechanical vehicle brake is also intended to be used as a parking brake. When the vehicle brake is configured to be self-releasing, a blocking lever is provided for implementing the parking brake function, which locks the mechanism of the vehicle brake so that the vehicle brake cannot be released.

[0004] However, automatic re-tensioning of the vehicle brakes may be required during parking of the vehicle, since the tensioning force of the vehicle brakes may decrease in the parking situation due to cooling of the vehicle brakes after parking.

[0005] To achieve this, the blocking lever must be released before the braking force is readjusted by the actuating electric motor. The blocking lever is then actuated again.

[0006] It is problematic here that, due to the self-releasing embodiment of the vehicle brake, the braking force can further weaken in the time window between the release of the blocking lever and the actuation of the electric motor. Summary of the invention

[0007] It is therefore an object of the present invention to provide a brake actuator, in particular for an electromechanical vehicle brake, which brake actuator has an improved parking brake function.

[0008] According to the invention, this object is achieved by a brake actuator, in particular a brake actuator for an electromechanical vehicle brake, having an electric motor for actuating the vehicle brake and a blocking module for selectively blocking the rotation of the output shaft of the electric motor to configure a parking brake function. The blocking module comprises a blocking rod mounted to be pivotable between a locking position and a release position and a blocking actuator for pivoting the blocking rod, wherein a blocking tooth is configured on the blocking rod, and in the locking position of the blocking rod, the blocking tooth engages with a gear coupled to the output shaft of the electric motor. The blocking tooth has a blocking geometry on one tooth flank and a lifting geometry on the opposite tooth flank, the geometry being configured such that: when the electric motor rotates in a first direction for increasing the braking force, the blocking rod is lifted against the spring force due to the rotation of the electric motor so as to disengage from the gear, and the rotation of the electric motor in the opposite direction for releasing the braking force is blocked, thereby realizing a ratchet function.

[0009] Due to the elastic mounting of the blocking lever and the lifting geometry achieved on the blocking tooth, it is not necessary to switch the blocking actuator when the electric motor is readjusted. In this way, it is avoided that the blocking lever is in the release position when the electric motor is not in operation. In other words, the blocking lever is released only by the rotation of the electric motor. As a result, it is ensured that the vehicle brake cannot be released further, but only the braking force can be increased in order to achieve a readjustment of the braking force in the parking state of the vehicle.

[0010] The blocking geometry on the blocking tooth also contributes to the fact that the vehicle brake cannot be released further in the parking state of the vehicle, since the vehicle brake prevents the electric motor from rotating in the corresponding direction.

[0011] In addition, the spring force acting on the blocking rod ensures that once the vehicle brake is readjusted, the blocking tooth engages the gear again and locks the vehicle brake. Specifically, whenever the blocking tooth moves over the tip of the tooth of the gear, the spring force engages the blocking tooth with the gear.

[0012] Preferably, the tooth flanks comprising the blocking geometry are configured to be steeper than the tooth flanks comprising the lifting geometry. As a result, the blocking geometry reliably blocks the rotation of the gear and thereby also the rotation of the motor in the direction of releasing the braking force. Conversely, the flatter tooth flanks with the lifting geometry enable the teeth of the gear to slide along the lifting geometry and thus lift the blocking lever during rotation of the motor.

[0013] For example, the blocking geometry of the blocking tooth extends orthogonally to the blocking rod. As a result, reliable locking can be guaranteed even under great force.

[0014] According to one embodiment, in the locked position of the blocking rod, the blocking tooth engages with the drive pinion directly arranged on the output shaft of the motor. Due to the size of the pinion, the torque acting on the drive pinion is relatively low, thereby the force acting on the blocking rod is also correspondingly low. This has realized the cost-effective basic design of the blocking rod. In other words, compared with the situation with higher torque, the blocking rod can be envisioned as more unstable.

[0015] The blocking actuator can include a bistable linear magnet. In this way, the blocking actuator can be locked in two end positions without being energized. As a result, the brake actuator can be operated in a particularly energy-saving manner. In particular, a single current pulse is sufficient to move the blocking actuator from one end position to the opposite end position.

[0016] The end positions of the blocking actuator correspond to the release position and the locking position of the blocking lever.

[0017] Preferably, a spring for applying a preload force to the blocking lever in the direction of the locking position is integrated in the blocking actuator, thereby protecting the spring from contamination and damage.

[0018] The blocking actuator can be a magnetic actuator having a movable linearly guided armature, which is displaceably connected to a tappet, which is coupled to the blocking rod, wherein the spring presses the tappet in a direction away from the blocking rod and, when compressed by the spring, the tappet can be displaced relative to the armature in a direction towards the blocking rod. Due to the compression of the spring, the blocking rod can be pivoted without activating the magnetic actuator. The spring is compressed, in particular when a force acts on the blocking rod during rotation of the electric motor, as a result of which the tappet is pulled out of the blocking actuator. In the process, the spring also prevents the armature from being moved by the pulling force acting on the tappet, thereby preventing any unintentional switching of the magnetic actuator.

[0019] In an alternative embodiment, a spring for applying a preload force in the direction of the locking position can be integrated in a bearing point of the blocking lever. This also enables the blocking lever to be pivoted without switching the blocking actuator.

[0020] Furthermore, the blocking actuator can alternatively have a linearly displaceable tappet, which is coupled to the blocking lever, wherein a spring is integrated in the coupling point so that the blocking lever is resiliently mounted relative to the blocking actuator. Here, the blocking lever can also be pivoted without switching the blocking actuator. The spring also prevents tensile forces that are high enough to move the armature of the blocking actuator from acting on the tappet.

[0021] The electric motor for driving can be coupled to an actuating slide through a gearbox unit and a spindle transmission mechanism, and the actuating slide for supporting the brake pad on the brake rotor can be selectively displaced between a retracted position and a deployed position. In this way, the rotation of the electric motor can be converted into a linear movement of the actuating slide, thereby causing an axial actuating force for supporting the brake pad on the brake rotor.

[0022] According to the invention, the object is also achieved by an electromechanical vehicle brake having a brake caliper, an actuating slide which can be linearly displaced in the brake caliper and which is used to support a brake pad on a brake rotor and can be selectively displaced between a retracted position and a deployed position, and having a brake actuator according to the invention, wherein an electric motor of the brake actuator for driving is coupled to the actuating slide via a gearbox unit and a spindle transmission.

[0023] As already described in the context of the brake actuator according to the invention, in the case of the vehicle brake according to the invention it is necessary to readjust the braking force in the parking state of the vehicle, thereby reliably avoiding an unintentional release of the vehicle brake. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Other advantages and features of the present invention will become apparent from the following description and referenced drawings. In the drawings:

[0025] Figure 1 A section through a vehicle brake according to the invention in the region of a spindle drive is shown;

[0026] Figure 2 A brake actuator according to the present invention is shown;

[0027] Figure 3 A blocking module of a brake actuator is shown;

[0028] Figure 4 shows the first state from Figure 3 A blocking actuator of a blocking module;

[0029] Figure 5 Shows the state from Figure 4 The blocking actuator;

[0030] Figure 6 Shows another state Figure 4 and Figure 5 A brake blocking actuator;

[0031] Figure 7 An alternative blocking module for a brake actuator according to the invention is shown;

[0032] Figure 8 A further alternative blocking module for a brake actuator according to the invention is shown; and

[0033] Fig. 9 A further alternative blocking module for a brake actuator according to the invention is shown. DETAILED DESCRIPTION

[0034] Figure 1 A vehicle brake 10 with a brake actuator 12 is shown in a sectional view. The vehicle brake 10 is an electromechanically actuatable brake.

[0035] exist Figure 2 1 shows the brake actuator 12 in a perspective view.

[0036] The vehicle brake 10 comprises a brake caliper 14 in which an intermediate space 16 for a brake rotor 18 is formed.

[0037] A brake pad 20 is arranged in this intermediate space and can be supported on the brake rotor 18 .

[0038] The brake pad 20 has a friction lining 22 and a back plate 24 connected to the friction lining.

[0039] The vehicle brake further comprises a spindle transmission 26, which in the exemplary embodiment is a ball screw mechanism, having a rotatably mounted spindle 28, which is driven by an electric motor and on which an actuating slide 30 is mounted. The spindle 28 serves to axially move the actuating slide 30. The actuating slide 30 forms a spindle nut of the spindle transmission 26. The actuating slide 30 specifically represents a brake piston.

[0040] In order to support the brake pad 20 on the brake rotor 18 , the actuation slide 30 is selectively displaceable between a deployed position and a retracted position by an axial displacement.

[0041] The actuation slide 30 is in particular guided in the brake caliper 14 and is thus secured against rotation.

[0042] The actuation slider 30 in the deployed position presses against the brake pad 20 and transmits the axial actuation force to the brake pad 20 .

[0043] like Figure 2 As shown, brake actuator 12 includes an electric motor 32 .

[0044] Furthermore, the brake actuator 12 comprises a gearbox unit 34 .

[0045] The electric motor 32 for driving is coupled to the actuating slide 30 through the gear box unit 34 and the spindle transmission mechanism 26 so as to shift the actuating slide 30 between the retracted position and the deployed position.

[0046] The axial displacement of the actuation slide 30 is caused in particular by the rotation of the spindle 28 .

[0047] The vehicle brake 10 forms the service brake of the vehicle. This means that the vehicle brake 10 is used to decelerate the vehicle in normal driving operation.

[0048] The vehicle brake 10 is thus configured to be self-releasing. This means that the actuating slide 30 can be automatically released from the brake pad 20 as soon as the electric motor 32 is inactive in normal driving operation.

[0049] In order to additionally implement a parking brake function, the brake actuator 12 has a blocking module 36 for selectively blocking a rotation of an output shaft 38 of the electric motor 32 .

[0050] Since the rotation of the output shaft 38 of the electric motor 32 is blocked, the vehicle brake 10 can no longer be automatically released.

[0051] The blocking module 36 has a blocking lever 40 which is mounted to be pivotable between a locking position and a releasing position, and a blocking actuator 42 for pivoting the blocking lever 40 .

[0052] The pivot radius of the blocking lever 40 is limited by the pawl 43 .

[0053] A blocking tooth 44 is formed on the blocking lever 40 , and in the locked position of the blocking lever 40 , the blocking tooth 44 engages with a gear coupled to the output shaft 38 of the electric motor 32 .

[0054] In the exemplary embodiment, in the locked position of the blocking lever 40 , the blocking tooth 44 engages with a drive pinion 46 disposed directly on the output shaft 38 of the electric motor 32 .

[0055] However, it is also conceivable that the blocking tooth 44 engages with another gear of the gearbox unit 34 .

[0056] However, since the drive pinion 46 generally has a smaller diameter than the other gears of the gearbox unit 34 , the engagement of the blocking lever 40 on the drive pinion is advantageous from the point of view of the torque acting on the blocking lever 40 .

[0057] Figure 3 A blocking module 36 is shown, in which the brake actuator 12 can be used. Figure 3 Also shown are the electric motor 32 and the drive pinion 46 .

[0058] The blocking rod 40 is Figure 3 is shown in its locked position.

[0059] from Figure 3 It can be seen that the blocking actuator 42 is a magnetic actuator and specifically comprises a bistable linear magnet.

[0060] Furthermore, the blocking actuator 42 comprises a movable linearly guided armature 48. The armature can be specifically Figure 4 and Figure 5 Shift between the two end positions shown in .

[0061] The armature 48 is connected to a tappet 50 which is coupled to the blocking rod 40 .

[0062] The blocking lever 40 is mounted pivotably at its end facing away from the tappet 50 in a bearing point 51 .

[0063] The tappet 50 is linearly displaceable by the armature 48 , thereby moving the blocking lever 40 from the locking position to the releasing position, and vice versa.

[0064] Figure 4 The blocking actuator 42 is shown in an extended state, which corresponds to the released position of the blocking lever 40 .

[0065] Figure 5 The blocking actuator 42 is shown in a retracted state, which corresponds to the locked position of the blocking lever 40 .

[0066] In parking situations, it is often necessary to readjust the braking force while the vehicle brakes cool after the vehicle has been parked.

[0067] This is possible by means of the brake actuator 12 according to the invention without having to activate the blocking actuator 42 , as a result of which the reliability of the parking brake function is increased.

[0068] For this purpose, the blocking lever 40 is resiliently mounted. The blocking tooth 44 also has a special geometry that enables a ratchet function.

[0069] The elastic mounting of the blocking rod 40 and the geometric shape of the blocking tooth 44 are described below by means of different embodiments.

[0070] exist Figures 3 to 6 In the exemplary embodiment shown, a spring 52 for applying a preload force to the blocking lever 40 in the direction of the locking position is integrated in the blocking actuator 42 .

[0071] In this embodiment, the tappet 50 is displaceably connected to the armature 48. Specifically, the tappet 50 is linearly guided in the armature 48.

[0072] The spring 52 presses the tappet 50 in a direction away from the blocking rod 40 .

[0073] When compressed by the spring 52 , the tappet 50 is displaceable relative to the armature 48 in a direction toward the blocking rod 40 .

[0074] The armature 48 has in particular a central recess 53 , wherein the recess 53 has a guide portion 54 , in which the tappet 50 is linearly guided, and a receiving portion 56 which adjoins the guide portion 54 and is widened compared to the guide portion 54 .

[0075] The spring 52 is received in the receiving portion 56. More specifically, the spring 52 in the receiving portion 56 circumferentially surrounds the tappet 50.

[0076] The spring 52 is supported on the armature 48 by one end and on the tappet 50 by the opposite end.

[0077] For this purpose, the tappet 50 has a laterally protruding appendage 57 on which the spring 52 is supported in order to impact the tappet 50 towards the locking position.

[0078] The attachment 57 is arranged on the end of the tappet 50 facing away from the blocking rod 40 .

[0079] In order to prevent the tappet 50 from slipping out of the armature 48 , the armature 48 has a cover 58 which closes the receiving portion 56 .

[0080] Due to the spring 52, it is possible to displace the tappet 50 even when the blocking actuator 42 is not switched, because the spring 52 is compressed by the tensile force acting on the tappet 50. Figure 6 shown.

[0081] Furthermore, the spring 52 can compensate for manufacturing tolerances between the armature 48 and the tappet 50 .

[0082] In order to realize the ratchet function, the blocking tooth 44 has a blocking geometry 61 on one tooth flank 60 and a lifting geometry 63 on the opposite tooth flank 62 .

[0083] The lifting geometry 63 is configured such that when the motor 32 rotates in the first direction for increasing the braking force, the blocking lever 40 is lifted against the spring force due to the rotation of the motor 32 , thereby disengaging from the drive pinion 46 .

[0084] More specifically, when the motor 32 rotates, the teeth of the drive pinion 46 slide along the lifting geometry 63 of the blocking tooth 44, so that the blocking tooth 44 is lifted from the drive pinion 46 and no longer meshes with the latter. As a result, a pulling force acts on the tappet 50, as a result of which the spring 52 is compressed again, so that the tappet 50 can be withdrawn from the blocking actuator 42 without the blocking actuator being switched.

[0085] When the tip of the blocking tooth 44 meets the tip of the tooth of the driving pinion 46 in the process, Figure 6 The status of the blocking actuator is shown.

[0086] Here, it is also ensured by the spring 52 that, in the event of a readjustment, the armature 48 does not move out of the latter end position, which could lead to an unintentional switching of the blocking actuator 42 .

[0087] The blocking geometry 61 is configured such that the rotation of the motor 32 in the opposite direction of releasing the braking force is blocked. Specifically, it is impossible to release the blocking tooth 44 from the meshing with the drive pinion 46 by the rotation of the motor 32 in the direction of releasing the braking force.

[0088] Specifically, the tooth flank 60 including the blocking geometry 61 is configured to be steeper than the tooth flank 62 including the lifting geometry 63 .

[0089] Therefore, the braking force can be readjusted without the risk of further reducing the braking force.

[0090] Figure 7 A blocking module 36 is shown for a brake actuator 12 according to the invention and according to a further exemplary embodiment.

[0091] according to Figure 7 The blocking module 36 is different from Figure 3 The blocking module 36 is shown.

[0092] exist Figure 7 In the illustrated embodiment, the blocking rod 40 has a rectangular portion between its two ends.

[0093] The blocking tooth 44 is provided adjacent to the tip of the rectangular portion.

[0094] In this embodiment, the blocking geometry of the blocking tooth 44 extends orthogonally to the blocking rod 40 .

[0095] according to Figure 7 The functional mode of the blocking module 36 is similar to Figure 3 The functional mode of the blocking module 36 is shown.

[0096] Specifically, the spring 52 is integrated in the blocking actuator 42, as shown in Figures 3 to 6as described in the context of .

[0097] Figure 8 A blocking module 36 is shown for a brake actuator 12 according to the invention and according to a further exemplary embodiment.

[0098] according to Figure 8 The blocking module 36 of the illustrated embodiment differs from the previous embodiments in the arrangement of the spring 52 .

[0099] In particular, the spring 52 is integrated in the coupling point 64 between the tappet 50 and the blocking lever 40. As a result, a resilient mounting of the blocking lever 40 relative to the blocking actuator 42 is also achieved.

[0100] Fig. 9 An alternative blocking module 36 for the brake actuator 12 according to the invention is also shown.

[0101] according to Fig. 9 The damping module 36 of the illustrated embodiment also differs from the preceding embodiments with regard to the arrangement of the spring 52 .

[0102] In particular, a spring 52 for exerting a preload force in the direction of the locking position is integrated into a bearing point 51 of the blocking lever 40 .

Claims

1. A brake actuator (12), in particular a brake actuator for an electromechanical vehicle brake (10), comprising: an electric motor (32) for actuating the vehicle brake (10); a blocking module (36) for selectively blocking the rotation of the output shaft (38) of the electric motor (32) to construct a parking brake function, in, The blocking module (36) comprises: a blocking rod (40) installed to be pivotable between a locking position and a releasing position; and a blocking actuator (42) for pivoting the blocking rod (40). A blocking tooth (44) is configured on the blocking rod (40), and in the locked position of the blocking rod (40), the blocking tooth is engaged with a gear connected to an output shaft (38) of the motor (32), The blocking tooth (44) has a blocking geometry (61) on one tooth side (60) and a lifting geometry (63) on the opposite tooth side (62), and the blocking geometry (61) and the lifting geometry (63) are configured so that: when the motor (32) rotates in a first direction for increasing the braking force, the blocking rod (40) is lifted against the spring force due to the rotation of the motor (32) so as to disengage from the gear; and the rotation of the motor (32) in the opposite direction for releasing the braking force is blocked.

2. The brake actuator (12) according to claim 1, characterized in that The tooth flank (60) including the blocking geometry (61) is configured to be steeper than the tooth flank (62) including the lifting geometry (63).

3. The brake actuator (12) according to claim 2, characterized in that The blocking geometry (61) of the blocking tooth (44) extends orthogonally to the blocking rod (40).

4. The brake actuator (12) according to any one of the preceding claims, characterized in that In the locked position of the blocking lever (40), the blocking tooth (44) engages with a drive pinion (46) disposed directly on the output shaft (38) of the electric motor (32).

5. The brake actuator (12) according to any one of the preceding claims, characterized in that The blocking actuator (42) includes a bistable linear magnet.

6. The brake actuator (12) according to any one of the preceding claims, characterized in that A spring (52) for applying a preload force to the blocking lever (40) in the direction of the locking position is integrated into the blocking actuator (42).

7. The brake actuator (12) according to claim 6, characterized in that The blocking actuator (42) is a magnetic actuator having a movable linearly guided armature (48) which is displaceably connected to a tappet (50) which is coupled to the blocking rod (40), wherein the spring (52) presses the tappet (50) in a direction away from the blocking rod (40) and when compressed by the spring (52), the tappet (50) can be displaced relative to the armature (48) in a direction toward the blocking rod (40).

8. The brake actuator (12) according to any one of claims 1 to 5, characterized in that A spring (52) for applying a preload force in the direction of the locking position is integrated into a bearing point (51) of the blocking lever (40).

9. The brake actuator (12) according to any one of claims 1 to 5, characterized in that The blocking actuator (42) has a linearly displaceable tappet (50) which is coupled to the blocking rod (40), wherein a spring (52) is integrated in a coupling point (64) so ​​that the blocking rod (40) is elastically mounted relative to the blocking actuator (42).

10. The brake actuator (12) according to any one of the preceding claims, characterized in that The electric motor (32) for driving is coupled to an actuating slide (30) through a gear box unit (34) and a spindle transmission mechanism (26), and is used to selectively shift the actuating slide (30) supporting the brake pad (20) on the brake rotor (18) between a retracted position and a deployed position.

11. An electromechanical vehicle brake (10) having a brake caliper (14), an actuating slide (30) which is linearly displaceable in the brake caliper (14) and which is selectively displaceable between a retracted position and a deployed position for supporting a brake pad (20) on a brake rotor (18), and having a brake actuator (12) according to any of the preceding claims, wherein The electric motor (32) for driving the brake actuator (12) is coupled to the actuating slide (30) via a gear box unit (34) and a spindle transmission (26).

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