Electromechanical brake

Abstract

The invention relates to an electromechanical brake (4) for braking a motor vehicle. The electromechanical brake (4) comprises an electric motor (8) with a shaft (36), by means of which a brake piston (20) can be moved axially for braking. A disc (52) is arranged on the shaft (36) and has a plurality of recesses (56) arranged in the circumferential direction. The electromechanical brake (4) also has a magnetic actuator (32) which axially displaces the pin (68) in such a way that one end of the pin (68) interacts with the recess (56) of the disc (52) and blocks a movement of the shaft (36) in the brake release direction, the pin (68) being bistable held. The magnetic actuator (32) and a controller (24) for controlling the electric motor (8) and the magnetic actuator (32) are arranged in the axial direction of the electric motor (8), and the pin (68) is movable parallel to the axis (36).

Description

Technical Field

[0001] The invention relates to an electromechanical brake for braking a motor vehicle. The invention also relates to a motor vehicle having such an electromechanical brake. Background Art

[0002] The service brake system is usually a brake that uses brake fluid to press the brake piston together with the brake friction lining onto the brake disc to brake the vehicle. However, the parking brake is constructed as an electromechanical brake. As the units in motor vehicles are increasingly electrified, the service brake system should also be constructed as an electromechanical brake, so that the brake fluid and the complex valve and pipeline structures associated therewith can be omitted. Such an electromechanical brake can also significantly reduce maintenance costs.

[0003] Patent document DE 102 34 848 A1 discloses an electromechanical brake which can be locked in an actuated state by means of a locking device. A service brake and a parking brake are thus formed. The brake is constructed as a disc brake having a brake caliper on which an electric motor and a transmission are arranged. The motor has a stator and a rotor, wherein the rotor is formed as a screw transmission which converts a rotational motion into a translational motion for pressing a brake friction lining onto a brake disc. A ratchet is connected to the rotor and has a plurality of sawtooth-shaped teeth. On the brake caliper, a pawl which can be held in a bistable manner by an electromagnet and a permanent magnet is arranged in the region of the ratchet, and the pawl cooperates with the ratchet to form a parking brake. Summary of the invention

[0004] The invention is based on the object of providing an electromechanical brake with a parking brake with which the assembly outlay and the space requirement can be reduced.

[0005] This object is achieved by an electromechanical brake having the subject matter of claim 1. Preferred embodiments emerge from the dependent claims.

[0006] The invention provides an electromechanical brake for braking a motor vehicle. The electromechanical brake comprises an electric motor with a shaft, by means of which a brake piston can be axially moved for braking. A disk is arranged on the shaft, the disk having a plurality of recesses arranged in a circumferential direction, and the electromechanical brake further comprises a magnetic actuator, which moves a pin axially so that one end of the pin cooperates with the recess of the disk and blocks the movement of the shaft in the brake release direction. The pin can be held bistable here. The magnetic actuator and a controller for controlling the electric motor and the magnetic actuator are arranged in the axial direction of the electric motor, and the pin can be moved parallel to the shaft.

[0007] Due to the bistable state, the pin can be stably held in both states without power supply. These states correspond to the driving state and the parking state. As a result, only electrical power is required to move the pin between stable positions. By blocking the movement in the brake release direction, a parking brake is formed so that the motor vehicle can be parked by braking. The axial arrangement of the controller and the magnetic actuator has the advantage that the space requirement can be kept very low. In addition, the axial arrangement allows the magnetic actuator to be connected directly to the controller. As a result, the wiring work can be kept very low. In addition, the assembly work and therefore the costs of such an electromechanical brake are reduced.

[0008] In a preferred embodiment of the invention, the disk is designed as a toothed disk. The toothed disk has teeth formed on the outer circumference, and recesses are formed between the teeth. The recesses for the pins can thus be easily provided by the toothed disk. The toothed disk is also available repeatedly on the market, so that there is no need to develop separate parts, which saves costs. The toothed disk is advantageously designed as a sheet metal part. The sheet metal part can be manufactured simply and economically. In addition, due to the thin-walled design, material costs and weight can be saved by such a sheet metal part.

[0009] In another preferred embodiment of the invention, the disk is constructed in the form of an axial fan impeller. An axial fan impeller is a component having fan blades which are forwarded in the axial direction at one end in the circumferential direction. Air can be conveyed in the axial direction by means of such an axial fan impeller. The movement of the axial fan impeller can be locked in a simple manner by means of a pin by means of the forward-facing fan blades. The axial fan impeller is advantageously formed by a plate part, so that the advantages described above can be achieved.

[0010] Preferably, the pin has a groove in the region of the axial end, which cooperates with the teeth of the toothed disk or with the fan blades of the axial fan impeller so that the pin can be held in a stable position. The groove is advantageously designed as a groove that circumferentially extends on the pin. The teeth or the fan blades snap into the groove, so that a stable position for the pin is thus formed in a simple manner. As a result, the pin can hold the brake in the braking state without current.

[0011] The axial end of the pin facing the disk preferably has a conical tip. This tip can be more easily introduced into the recess.

[0012] In an advantageous development, the pin has a widening at one axial end, which cooperates with the teeth of the toothed disk or with the fan blades of the axial fan impeller so that the pin can be held in a stable position. The widening is here an increase in diameter at the axial end. Such a widening can also stabilize the pin.

[0013] Advantageously, the pin is constructed in multiple parts along the axial length. These parts are assembled together during assembly. As a result, the widening or the groove can be produced separately, which simplifies production. In addition, assembly is also simplified due to the shortened length of the pin.

[0014] Advantageously, the fan blade formed by the axial fan impeller is advanced in the direction of the magnetic actuator in the brake release rotation direction of the axial fan impeller, so that pressure can be applied to the pin in the direction of the magnetic actuator by the fan blade in the brake rotation direction. The brake release rotation direction is here the rotation direction of the axial fan blade, wherein the brake piston moves back, thereby reducing the applied braking force. Accordingly, the brake is released in this direction. By rotating the axial fan impeller in the brake rotation direction, the pin slides on the surface of the next fan blade and is thereby pressed in the direction of the magnetic actuator. Thus, the pin can be moved axially in the direction of the disk by simply energizing the magnetic actuator. The forward-facing fan blade can also be used in combination with a pin that is retracted via a spring. In this case, if, for example, the pin is stuck and cannot be retracted by the spring, the forward-facing fan blade will become redundant to the spring.

[0015] In a further advantageous embodiment, the magnetic actuator has a latching mechanism, by means of which the pin can be held in a bistable manner. With such a latching mechanism, a groove or a widening on the pin can be omitted. The pin is thus held stably in two positions only by the latching mechanism. The latching mechanism is advantageously formed from plastic. As a result, the latching mechanism can be manufactured simply, cost-effectively and lightly.

[0016] According to an expedient embodiment, a rotation speed sensor is arranged in the controller to measure the rotation speed of the electric motor. Since the controller is arranged axially relative to the electric motor, the controller is arranged at one end of the shaft of the electric motor. As a result, the rotation speed sensor can be positioned in the controller, thereby eliminating the need for wiring the rotation speed sensor. This significantly simplifies the assembly work.

[0017] According to another suitable embodiment, the magnetic actuator is arranged in a hole in the housing of the electromechanical brake. The magnetic actuator is arranged completely or at least partially in the hole. Preferably, the magnetic actuator is arranged completely in the hole. This reduces the space required for the magnetic actuator. As a result, such an electromechanical brake can be made smaller.

[0018] The invention also provides a motor vehicle having an electromechanical brake according to the invention. The advantages described above are achieved with such a motor vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Embodiments of the present invention are shown in the accompanying drawings and will be explained in more detail in the following description. In which:

[0020] Figure 1 A perspective view showing an electromechanical brake according to an embodiment of the present invention;

[0021] Figure 2 A partial cross-sectional view of an electromechanical brake according to an embodiment of the present invention is shown;

[0022] Figure 3 a shows a top view of an axial flow fan impeller with a pin according to an embodiment of the present invention;

[0023] Figure 3 b shows the Figure 3 a is a side view of an axial fan impeller with a pin,

[0024] Figure 4 a shows an embodiment of a latch mechanism in a driving position of a motor vehicle;

[0025] Figure 4 b shows the current state of the magnetic actuator according to Figure 4 A locking mechanism;

[0026] Figure 4 c shows the braking state of the motor vehicle according to Figure 4 a locking mechanism. DETAILED DESCRIPTION

[0027] Figure 1 A perspective view of an electromechanical brake 4 according to an embodiment of the present invention is shown. The electromechanical brake 4 comprises an electric motor 8 connected to a housing 12. A transmission unit 16 arranged in the housing 12 can be driven by the electric motor 8. A brake piston 20 arranged in the housing 12 is operatively connected to the transmission unit 16, so that the brake piston 20 can be axially moved when the electric motor 8 is driven in order to apply a braking force.

[0028] A control unit 24 is arranged on the housing 12 on the side of the housing 12 facing away from the electric motor 8. The electric motor 8 can be controlled by means of the control unit 24. A hole 28 is formed in the housing 12, in which a magnetic actuator 32 is arranged. One end of the magnetic actuator 32 is contacted here via the control unit 24 and is controlled via the control unit.

[0029] Figure 2 1 shows a partial cross-sectional view of an electromechanical brake 4 according to an embodiment of the present invention. The figure shows a shaft 36 of an electric motor 8, on which a worm 40 for driving a transmission unit 16 is constructed. The shaft 36 is supported at opposite ends of the housing 12. A controller 24 is arranged on the housing 12 in the axial direction of the electric motor 8, and the magnetic actuator 32 and the electric motor 8 can be controlled by the controller. A rotation speed sensor 48 is arranged in the controller 24, and the rotation speed of the shaft 36 can be measured by the rotation speed sensor.

[0030] Furthermore, a disk 52 is arranged on the shaft 36 in a rotationally fixed manner, which disk has a plurality of recesses 56 (see Figure 3 a). In this figure, the magnetic actuator 32 is shown in the hole 28. The magnetic actuator 32 is also arranged in the axial direction of the electric motor 8. In addition, the magnetic actuator 32 is arranged below the controller 24 in the hole 28 of the housing 12. As a result, the contact part 60 of the magnetic actuator 32 protrudes directly into the controller 24, so that it can be connected to the controller 24 without wiring work.

[0031] The magnetic actuator 32 has a coil 64, by means of which a pin 68 can be moved in the axial direction of the magnetic actuator 32. The pin 68 is arranged parallel to the shaft 36. The pin 68 has a conical tip 72 at the axial end facing the disk 52, by which the recess 56 can be found more easily. In the region of the axial end, a groove 76 is additionally formed, which is formed here as an axial fan impeller (see Figure 3 ) is locked into the recess. Although the invention is explained here with reference to a disk 52 designed as an axial fan impeller, the disk 52 can also be designed as a toothed disk. The fan blade 80 that is locked into the recess 76 prevents the pin 68 from returning. The pin 68 is thus held stably in this position. After the brake is activated, the pin 68 moves axially in the direction of the disk 52, so that the disk 52 locks the brake and thus forms a parking brake.

[0032] Figure 3 b shows the Figure 3 a is a side view of an axial flow fan impeller 52 with a pin 68. The pin 68 is Figure 2 The pin 68 shown differs in that a widening 84 is formed at the axial end instead of a groove 76. The widening 84 also makes it possible to hold the pin 68 stably in position via the fan blade 80. Figure 3 b also shows how the fan blade 80 is designed. The fan blade 80 here is forward in the circumferential direction. In other words, one end of the fan blade 80 in the circumferential direction extends in the axial direction. The fan blade 80 is designed here so that the forward end 88 of the fan blade 80 in the direction of rotation of the disk corresponding to the brake release direction of rotation strikes the pin 68 which can be axially moved in the direction of the electric motor 8. This prevents the parking brake from being released.

[0033] After the pin 68 is locked, the pin 68 can be released by rotating the axial fan impeller 52 in the direction of brake tensioning. The axial end of the pin 68 slides on the upper side of the fan blade 80. Due to the forward-facing configuration of the fan blade 80, the pin 68 moves axially in the direction of the magnetic actuator 32. As a result, the rotation of the axial fan impeller 52 in the brake release direction is released.

[0034] Figure 4 Figure 1 shows an embodiment of a latch mechanism 92 in the driving position of a motor vehicle. In the driving position, the pin 68 is spaced apart from the disk 52 so that the disk 52 can perform a rotational movement. The latch mechanism 92 is arranged between the magnetic actuator 32 and the pin 68. The latch mechanism 92 is formed by an inner ring 96 and an outer ring 100 surrounding the inner ring 96. The inner ring 96 has a sawtooth structure. Small notches 108 and large notches 112 are alternately formed between the saw teeth 104. The outer ring 100 has a sawtooth structure similar to the inner ring 96 with alternating notches. The sawtooth structure of the inner ring 96 and the sawtooth structure of the outer ring 100 are arranged spaced apart from each other in the axial direction.

[0035] Pins 116 extending in the radial direction are arranged on the pins 68 in the region of the latching means 92. The pins 116 are designed to cooperate with the sawtooth structure of the inner ring 96 and the sawtooth structure of the outer ring 100. Figure 4 In the state shown in a, the pin 116 is located in the small recess 108 of the inner ring 96. This can stably maintain the state in which the pin 68 is spaced apart from the disk 52.

[0036] Figure 4 b shows the state in which the magnetic actuator 32 is energized. Figure 4 The latch mechanism 92 of a. Here, the magnetic actuator 32 is energized so that the pin 68 is pulled in the opposite direction to the disk 52. The pin 116 has been pulled into the notch 124 of the outer ring 100 by the serrations 120 of the outer ring 100. As a result, the pin 68 is rotated by an angular amount.

[0037] Figure 4 c shows the braking state of the motor vehicle according to Figure 4 a latch mechanism 92. In this state, the pin 116 is arranged in the large recess 112. The pin 116 is here Figure 4 Starting from the state in c, the bevel of the sawtooth 104 of the inner ring 96 enters the large recess 112. In this state, the pin 68 moves in the direction of the disk 52, so that the disk 52 can be locked by the pin 68. Figure 4 In the state shown in c, the pin 68 can also be held stably here, so that a bistable state is formed in a simple manner by the latching mechanism 92 .

Claims

1. An electromechanical brake (4) for braking a motor vehicle, comprising an electric motor (8) with a shaft (36), by which a brake piston (20) can be axially displaced for braking, wherein: A disk (52) is arranged on the shaft (36), the disk having a plurality of recesses (56) arranged in the circumferential direction, and the electromechanical brake further comprises a magnetic actuator (32), which moves a pin (68) axially so that one end of the pin (68) cooperates with the recess (56) of the disk (52) and locks the movement of the shaft (36) in the brake release direction, wherein the pin (68) can be held bistable, It is characterized in that The magnetic actuator (32) and a controller (24) for controlling the electric motor (8) and the magnetic actuator (32) are arranged along the axial direction of the electric motor (8), and the pin (68) is movable parallel to the shaft (36).

2. The electromechanical brake (4) according to claim 1, characterized in that The disk (52) is designed as a toothed disk.

3. The electromechanical brake (4) according to claim 1, characterized in that The disk (52) is configured in the form of an axial flow fan impeller.

4. The electromechanical brake (4) according to claim 2 or 3, characterized in that The pin (68) has a groove (76) in the region of an axial end, which cooperates with the teeth of the toothed disk or with the fan blades (80) of the axial fan impeller (52) to hold the pin (68) in a stable position.

5. The electromechanical brake (4) according to claim 2 or 3, characterized in that The pin (68) has a widening (84) at one axial end, which cooperates with the teeth of the toothed disk or with the fan blades (80) of the axial fan impeller (52) to hold the pin (68) in a stable position.

6. The electromechanical brake (4) according to claim 4 or 5, characterized in that The fan blades (80) formed by the axial flow fan impeller (52) advance in the direction of the magnetic actuator (32) along the brake release rotation direction of the axial flow fan impeller (52), so that pressure can be applied to the pin (68) along the brake rotation direction toward the magnetic actuator (32) by the fan blades (80).

7. The electromechanical brake (4) according to any one of claims 1 to 3, characterized in that The magnetic actuator (32) has a latching mechanism (92) by which the pin (68) can be held in a bistable manner.

8. Electromechanical brake (4) according to any one of the preceding claims, characterized in that A rotation speed sensor (48) is arranged in the controller (24) to measure the rotation speed of the electric motor (8).

9. Electromechanical brake (4) according to any one of the preceding claims, characterized in that The magnetic actuator (32) is arranged in a bore (28) of a housing (12) of the electromechanical brake (4).

10. Motor vehicle comprising an electromechanical brake (4) according to any one of the preceding claims.

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