Electric braking device and method for assembling electric braking device

Abstract

This electric braking device (1) is configured such that a claw part (21A) having an engaging claw (210) and a pressing mechanism (121) can be mechanically separated, and is provided with: a circuit board (11) that supplies power to an electric motor (23) and an electric drive unit (120); a first case (10) to which the circuit board (11), the electric drive unit (120), and the pressing mechanism (121) are fixed; and a second case (20) to which the claw part (21A) and a ratchet gear (22) are fixed.

Description

Electric braking device and method for assembling an electric braking device

[0001] The present disclosure relates to an electric braking device and a method for assembling an electric braking device.

[0002] Patent Document 1 discloses a braking device in which an electric motor and a locking mechanism are assembled to a gear case that houses a speed reducer, and a board case that houses a circuit board is assembled to the gear case.

[0003] U.S. Patent Application Publication No. 2023 / 150467

[0004] In the braking device disclosed in Patent Document 1, when assembling the gear case and the board case, the electric motor housed in the gear case and the solenoid of the locking mechanism are arranged in the same assembly and are electrically connected to the circuit board. In these electrical connections, since the dimensional tolerances and assembly tolerances of each component are stacked, high dimensional accuracy and assembly accuracy are required for each component. One aspect of the present disclosure aims to provide an electric braking device that can be easily assembled.

[0005] To solve the above problems, an electric braking device according to one aspect of the present disclosure amplifies the rotational torque of an electric motor with a reduction gear, converts the rotational torque amplified by the reduction gear into axial force with a linear motion conversion mechanism, and uses the axial force converted by the linear motion conversion mechanism to press a friction member against a rotating member that rotates together with the wheel of a vehicle, thereby generating a braking force on the wheel, comprising: a ratchet gear that is rotationally driven by the rotational torque of the electric motor; and a drive unit having a meshing pawl that transitions the state of the meshing pawl between a meshed state in which it is meshed with the ratchet gear and a non-mesh state in which the meshing state is released. The electric braking device comprises, the drive unit having a claw portion having the occlusal claw, a pressing mechanism that presses the claw portion to transition the occlusal claw from the non-occlusal state to the occlusal state, and an electric unit that drives the pressing mechanism, wherein the claw portion and the pressing mechanism are configured to be mechanically separable, and the device comprises a circuit board that supplies power to the electric motor and the electric unit, a first case to which the circuit board, the electric unit and the pressing mechanism are fixed, and a second case which is a separate case from the first case to which the claw portion and the ratchet gear are fixed.

[0006] According to one aspect of this disclosure, an electric braking system can be easily assembled.

[0007] This is a schematic diagram showing an example configuration of an electric braking device according to one embodiment of the present disclosure. This diagram shows the relationship between the engaging pawl and the ratchet gear. This diagram is used to explain the assembly method of the electric braking device according to one embodiment of the present disclosure.

[0008] Figure 1 is a schematic diagram showing one configuration example of an electric braking device according to one embodiment of the present disclosure. The electric braking device 1 shown in Figure 1 is a braking device that generates braking force on the wheels of a vehicle by pressing a friction member 27 against a rotating member 30 that rotates together with the wheels of the vehicle. The electric braking device 1 comprises a first case 10, a circuit board 11, a first drive unit 12, a second case 20, a second drive unit 21, a ratchet gear 22, an electric motor 23, a reduction gear 24, a linear motion conversion mechanism 25, a piston 26, a friction member 27, and a cylinder 28.

[0009] The first case 10 has a first part 10A and a second part 10B. The circuit board 11 and the first drive unit 12 are fixed to the first part 10A. The second part 10B is the lid of the first part 10A. The circuit board 11 controls each part of the electric braking device 1. The circuit board 11 has a first connection part 11A and a second connection part 11B. The first connection part 11A and the second connection part 11B are, for example, terminal holes into which power supply pins can be inserted. The circuit board 11 supplies power to the devices electrically connected to the first connection part 11A and the second connection part 11B. Either the front or back surface of the circuit board 11 faces the second part 10B, and the other side faces the second case 20. Between the circuit board 11 and the second case 20, there is a first fixing part 10C for fixing the first drive unit 12, and a housing part 10D for housing the second drive unit 21, ratchet gear 22, etc., which are fixed to the second case 20.

[0010] The first drive unit 12 and the second drive unit 21 are examples of drive units. The first drive unit 12 and the second drive unit 21 are configured to be mechanically separable. The first drive unit 12 is fixed to the first fixed part 10C of the first case 10, and the second drive unit 21 is fixed to the second case 20. The first drive unit 12 is, for example, a solenoid actuator. The first drive unit 12 has an electric part 120, a pressing mechanism 121, and a first power supply pin 122. The second drive unit 21 has a claw part 21A and a case 21B.

[0011] The first power supply pin 122 is electrically connected to the circuit board 11. Power is supplied to the first drive unit 12 from the circuit board 11 via the first power supply pin 122. The motorized part 120 is, for example, a solenoid coil. The pressing mechanism 121 is, for example, a plunger (movable iron core). The motorized part 120 drives the pressing mechanism 121.

[0012] The pawl portion 21A of the second drive unit 21 is, for example, a locking pin having an occlusal pawl 210, a locking portion 211, and a biasing portion 212. The occlusal pawl 210 is a pawl that can occlude with the teeth of the ratchet gear 22. The biasing portion 212 biases the pawl portion 21A in a direction that moves the occlusal pawl 210 away from the ratchet gear 22. The locking portion 211 locks the pawl portion 21A to the inside of the case 21B. The locking portion 211 is pressed against the inner wall of the case 21B by the biasing force of the biasing portion 212. The case 21B has an opening 21C on the surface facing the first drive unit 12 into which the pressing mechanism 121 can be inserted.

[0013] The electric motor 23 has a motor shaft 230 and a second power supply pin 231. The second power supply pin 231 is electrically connected to the circuit board 11. Power is supplied to the electric motor 23 from the circuit board 11 via the second power supply pin 231. The ratchet gear 22 is fixed to the motor shaft 230 of the electric motor 23. The rotational torque of the electric motor 23 is amplified by the reduction gear 24 and transmitted to the linear motion conversion mechanism 25. The linear motion conversion mechanism 25 has a rotating shaft 25A and a linear motion section 25B. The linear motion conversion mechanism 25 converts the rotational torque of the electric motor 23 into axial force.

[0014] The piston 26 is fixed to the linear motion section 25B of the linear motion conversion mechanism 25. The linear motion section 25B and the piston 26 move linearly in a direction corresponding to the rotation direction of the motor shaft 230 of the electric motor 23. The axial force converted linearly by the linear motion conversion mechanism 25 causes the piston 26 to press the friction member 27 against the rotating member 30.

[0015] When a magnetic field is generated by current flowing through the windings of the electric unit 120, the tip 121A of the pressing mechanism 121 protrudes from the first part 10A of the first case 10 and contacts the contact surface 211A of the locking part 211 of the claw part 21A through the opening 21C. The pressing mechanism 121 pushes the claw part 21A toward the ratchet gear 22 against the biasing force of the biasing part 212.

[0016] Figure 2 shows the relationship between the occlusal pawl and the ratchet gear. The occlusal pawl 210 is configured to transition between an occlusal state, shown by a dashed line in Figure 2, and a non-occlusal state, shown by a solid line in Figure 2. In the occlusal state, the occlusal pawl 210 is engaged with the teeth of the ratchet gear 22. In the occlusal state, the motor shaft 230 is rotatable in the forward direction Fwd, but is constrained not to rotate in the reverse direction Rvs. The non-occlusal state is the state in which the occlusal state is resolved, and the occlusal pawl 210 is not engaged with the teeth of the ratchet gear 22. In the non-occlusal state, the motor shaft 230 is rotatable in both the forward direction Fwd and the reverse direction Rvs.

[0017] The pressing mechanism 121 pushes the claw portion 21A against the biasing force of the biasing portion 212, causing the occlusal claw 210 of the claw portion 21A to press against the ratchet gear 22. As the reaction force of the pressing force is transmitted while the claw is pressed against the ratchet gear, the motor shaft 230 rotates in the reverse direction Rvs, and when the ratchet gear 22 abuts against the occlusal claw 210, the occlusal claw 210 transitions to an occlusal state.

[0018] The occlusal claw 210 will not transition to a non-occlusal state as long as rotational torque is generated in the reversal direction Rvs after it has entered an occlusal state. To release the occlusal state of the occlusal claw 210, for example, the following can be done: Motor torque is generated by the electric motor 23 to eliminate rotational torque in the reversal direction Rvs, causing the ratchet gear 22 to rotate in the forward direction Fwd. By reducing the current flowing through the windings of the electric unit 120 to below a predetermined value, the biasing force of the biasing unit 212 separates the occlusal claw 210 from the ratchet gear 22.

[0019] Figure 3 is a diagram used to illustrate an assembly method for an electric braking device according to one embodiment of the present disclosure. In the following description, the assembly method for the first drive unit 12 and the second drive unit 21 of the electric braking device 1 will be described. The assembly method for the electric braking device 1, as described using Figure 3, includes a first fixing step, a second fixing step, a motor mounting step, and an assembly step.

[0020] (First Fixing Process) The first fixing process is the process of fixing the circuit board 11 and the first drive unit 12 to the first case 10. More specifically, in the first fixing process, the electric unit 120 and the pressing mechanism 121 are fixed to the first fixing part 10C of the first part 10A of the first case 10, and the circuit board 11 is fixed to the first part 10A of the first case 10.

[0021] The first drive unit 12 may be fixed to the first fixed part 10C by fastening members such as screws, snap-fits, etc. If the first drive unit 12 is fixed to the first case 10 by fastening members, insert nuts or the like may be provided on the first case 10. The electric part 120 of the first drive unit 12 may be insert-molded when the first case 10 is molded.

[0022] When fixing the circuit board 11 to the first case 10, the fixing position of the circuit board 11 relative to the first case 10 is determined such that the first power supply pin 122 of the first drive unit 12 is connected to the first connection part 11A. When the first power supply pin 122 of the first drive unit 12 is connected to the first connection part 11A of the circuit board 11, power can be supplied from the circuit board 11 to the first drive unit 12.

[0023] (Motor Installation Process) The motor installation process is the process of fixing the electric motor 23 to the second case 20. The electric motor 23 is attached to the second case 20 so that the ratchet gear 22 can be fixed in a position that allows the occlusal jaw 210 to transition between an occlusal state and an unocclusal state. In Figure 3, the second drive unit 21 is fixed to the first surface 20A of the second case 20, and the electric motor 23 is attached to the second surface 20B opposite to the first surface 20A. Fasteners such as screws or snap-fits may be used to attach the electric motor 23. The motor shaft 230 of the electric motor 23 penetrates the second case 20 from the second surface 20B to the first surface 20A. The second power supply pin 231 of the electric motor 23 extends from the first surface 20A side to the second surface 20B side of the second case 20 in a position that does not come into contact with the ratchet gear 22, etc., when assembling the electric braking device 1.

[0024] (Second Fixing Process) The second fixing process is the process of fixing at least the claw portion 21A and the ratchet gear 22 to the second case 20. The ratchet gear 22 is fixed to the motor shaft 230 of the electric motor 23 which is fixed to the second case 20 by the motor mounting process.

[0025] The claw portion 21A may, for example, be incorporated into the case 21B and fixed to the first surface 20A of the second case in the state of the second drive unit 21. The case 21B may be manufactured integrally with the second case 20, in which case the claw portion 21A may be insert-molded during the molding of the second case 20. Alternatively, the claw portion 21A may be inserted into the case 21B which is integrally molded with the second case 20. In the second fixing step, the reducer 24, the linear motion conversion mechanism 25, etc., are also fixed to the second case 20.

[0026] (Assembly Process) The assembly process is performed after the first fixing process, the motor mounting process, and the second fixing process. The first part 10A of the first case 10 after the first fixing process and the second case 20 after the second fixing process are assembled. For example, each part fixed to the first side 20A of the second case 20 is housed in the housing part 10D of the first part 10A so that the second power supply pin 231 of the electric motor 23 attached to the second case 20 is connected to the second connection part 11B of the circuit board 11 fixed to the first part 10A. Power is supplied from the circuit board 11 to the electric motor 23 by connecting the second power supply pin 231 of the electric motor 23 to the second connection part 11B of the circuit board 11. After connecting the second power supply pin 231 to the second connection part 11B and housing the second drive unit 21 and the ratchet gear 22 in the housing part 10D, the second case 20 and the first part 10A are fixed together. For fixing the second case 20 to the first part 10A, fastening members such as screws or snap-fits may be used. Then, the second part 10B is fixed to the first part 10A. For fixing the second part 10B to the first part 10A, fastening members such as screws, snap-fits, welding, etc. may be used.

[0027] The area of ​​the opening 21C and the contact surface 211A of the second drive unit 21 are larger than the area of ​​the contact surface of the tip 121A of the pressing mechanism 121. Therefore, in the assembly process, sufficient tolerance can be ensured in the assembly accuracy between the pressing mechanism 121 and the claw portion 20A. The area of ​​the opening 21C and the contact surface 211A of the second drive unit 21 may be brought closer to the area of ​​the contact surface of the tip 121A of the pressing mechanism 121, as long as sufficient tolerance can be ensured.

[0028] The tip portion 121A of the pressing mechanism 121 and the case 21B of the second drive unit 21 may be provided with a tapered portion such that the pressing mechanism 121 retracts toward the first fixing portion 10C when the pressing mechanism 121 comes into contact with the case 21B during the assembly process. This reduces the possibility of the pressing mechanism 121 being damaged or the surface of the case 21B being scratched during the assembly process.

[0029] The first fixing process may be performed simultaneously with the motor mounting process and the second fixing process, or before the motor mounting process, or after the second fixing process and before the assembly process.

[0030] [Modification] In the above embodiment, the claw portion 21A of the second drive unit 21 has a locking portion 211. However, the claw portion 21A of the second drive unit 21 does not need to have a locking portion 211, as long as it is configured so that it does not come out of the case 21B due to the biasing force of the biasing portion 212. For example, the second drive unit 21 may have a portion on the opening 21C side of the case 21B that locks the claw portion 21A but does not lock the pressing mechanism 121. Also, the area of ​​the tip portion 121A of the pressing mechanism 121 may be larger than the contact surface 211A of the locking portion 211 of the claw portion 21A, as long as it is large enough to pass through the opening 21C of the case 21B.

[0031] In the above embodiment, the occlusal claw 210 transitions to an occlusal state when the pressing mechanism 121 pushes the claw portion 21A against the biasing force of the biasing portion 212. Alternatively, the occlusal claw 210 transitions to an unocclusal state when the ratchet gear 22 is rotated in the Fwd direction, and the biasing force of the biasing portion 212 separates the occlusal claw 210 from the ratchet gear 22. However, the method for transitioning the state of the occlusal claw 210 between the occlusal state and the unocclusal state is not limited to the above method. For example, the first drive unit 12 may be composed of an electric motor and a linear motion conversion mechanism. Alternatively, a lever or the like may be provided on the claw portion 21A, and the pressing mechanism 121 may operate the lever or the like.

[0032] In the above embodiment, the ratchet gear 22 is fixed to the motor shaft 230 of the electric motor 23. However, the ratchet gear 22 does not need to be directly fixed to the motor shaft 230 of the electric motor 23, as long as it is configured to be rotationally driven by the rotational torque of the electric motor 23. If the ratchet gear 22 is not fixed to the motor shaft 230 of the electric motor 23, the ratchet gear 22 may be fixed to the second case 20 in the second fixing step, and then the electric motor 23 may be fixed to the second case 20 in the motor mounting step. If the ratchet gear 22 is not fixed to the motor shaft 230 of the electric motor 23, the electric motor 23 does not need to be fixed to the second case.

[0033] [Summary] An electric braking device according to one aspect of the present disclosure is an electric braking device that amplifies the rotational torque of an electric motor with a reduction gear, converts the rotational torque amplified by the reduction gear into axial force with a linear motion conversion mechanism, and uses the axial force converted by the linear motion conversion mechanism to press a friction member against a rotating member that rotates together with the wheel of a vehicle, thereby generating a braking force on the wheel, comprising: a ratchet gear that is rotationally driven by the rotational torque of the electric motor; and a drive unit that has a meshing pawl and transitions the state of the meshing pawl between a meshed state in which it is engaged with the ratchet gear and a non-mesh state in which the meshing state is released. In the electric braking device, the drive unit includes a claw portion having the occlusal claw, a pressing mechanism that presses the claw portion to transition the occlusal claw from the non-occlusal state to the occlusal state, and an electric unit that drives the pressing mechanism, wherein the claw portion and the pressing mechanism are configured to be mechanically separable, and the device comprises a circuit board that supplies power to the electric motor and the electric unit, a first case to which the circuit board, the electric unit and the pressing mechanism are fixed, and a second case, which is a separate case from the first case, to which the claw portion and the ratchet gear are fixed. In the electric braking device of this disclosure, the claw portion having the occlusal claw that can occlude with the ratchet gear and the pressing mechanism are configured to be mechanically separable. This allows the claw portion and the pressing mechanism to be separated and fixed to the first case and the second case, respectively. Here, the circuit board and the electric unit are components that require reliable electrical connection. Furthermore, the cleavage pawl and the ratchet gear are components that require high assembly precision from each other. By fixing the circuit board and the electric unit that receives power from the circuit board to the first case, the electrical connection between the circuit board and the electric unit can be easily ensured. By fixing the cleavage pawl and the ratchet gear to the second case, the assembly precision between the cleavage pawl and the ratchet gear can be easily ensured. Therefore, the electric braking device can be easily assembled.

[0034] In one aspect of the present disclosure, the contact surface of the pressing mechanism and the contacted surface of the claw, which come into contact when the pressing mechanism presses the claw, have different areas. In the present disclosure, the contact surface of the pressing mechanism and the contacted surface of the claw, which come into contact when the pressing mechanism presses the claw, have different areas. This ensures that there is an allowable error in the assembly accuracy between the claw and the pressing mechanism, making it easier to assemble the first case and the second case.

[0035] In an electric braking device according to one aspect of the present disclosure, the electric motor is mounted on the second case and has a power supply pin that receives power from the circuit board, and the power supply pin contacts a connection portion provided on the circuit board. In the electric braking device of the present disclosure, the electric motor is mounted on the second case, and power is supplied to the electric motor via the electric motor's power supply pin that contacts the connection portion of the circuit board. Here, as described above, the electrical connection between the electric unit and the circuit board is ensured. Therefore, when assembling the first case and the second case, it is only necessary to pay attention to bringing the electric motor's power supply pin into contact with the connection portion of the circuit board. In other words, assembly of the first case and the second case becomes easy.

[0036] An assembly method for an electric braking device according to one aspect of the present disclosure is an assembly method for an electric braking device according to the above aspect, comprising: a first fixing step of fixing the circuit board, the electric unit, and the pressing mechanism to the first case; a second fixing step of fixing the pawl and the ratchet gear to the second case; and an assembly step of assembling the first case and the second case after the first and second fixing steps. The first fixing step makes it easy to ensure the electrical connection between the circuit board and the electric unit as described above. The second fixing step makes it easy to ensure the assembly accuracy of the meshing pawl and the ratchet gear as described above.

[0037] An electric braking device according to one aspect of the present disclosure is a method for assembling the electric braking device according to the above aspect, comprising: a first fixing step of fixing the circuit board, the electric unit, and the pressing mechanism to the first case; a motor mounting step of attaching the electric motor to the second case; a second fixing step of fixing the pawl and the ratchet gear to the second case; and an assembly step of aligning the power supply pin of the electric motor with the connection part of the circuit board after the first fixing step, the second fixing step, and the motor mounting step, and assembling the first case and the second case. The first case and the second case can be easily assembled as described above by the first fixing step, the second fixing step, the motor mounting step, and the assembly step.

[0038] [Additional Notes] This disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this disclosure.

Claims

1. An electric braking device that amplifies the rotational torque of an electric motor with a reduction gear, converts the rotational torque amplified by the reduction gear into axial force with a linear motion conversion mechanism, and uses the axial force converted by the linear motion conversion mechanism to press a friction member against a rotating member that rotates together with the wheel of a vehicle, thereby generating braking force on the wheel, comprising: a ratchet gear that is rotationally driven by the rotational torque of the electric motor; a drive unit that has a clenching pawl and transitions the state of the clenching pawl between a clenched state in which it is engaged with the ratchet gear and a non-clenched state in which the clenching state is released, wherein the drive unit comprises a pawl portion having the clenching pawl, a pressing mechanism that presses the pawl portion to transition the clenching pawl from the non-clenched state to the clenched state, and an electric unit that drives the pressing mechanism, wherein the pawl portion and the pressing mechanism are configured to be mechanically separable, and a circuit board that supplies power to the electric motor and the electric unit, An electric braking device characterized by comprising: a first case to which the circuit board, the electric unit, and the pressing mechanism are fixed; and a second case, which is a separate case from the first case, to which the pawl and the ratchet gear are fixed.

2. The electric braking device according to claim 1, wherein the contact surface of the pressing mechanism and the contacted surface of the claw that come into contact when the pressing mechanism presses the claw have different areas.

3. The electric braking device according to claim 1 or 2, wherein the electric motor is mounted on the second case and has a power supply pin that receives power from the circuit board, and the power supply pin contacts a connection portion provided on the circuit board.

4. A method for assembling an electric braking device according to claim 1 or 2, comprising: a first fixing step of fixing the circuit board, the electric unit, and the pressing mechanism to the first case; a second fixing step of fixing the pawl unit and the ratchet gear to the second case; and an assembly step of assembling the first case and the second case after the first fixing step and the second fixing step.

5. A method for assembling an electric braking device according to claim 3, comprising: a first fixing step of fixing the circuit board, the electric unit, and the pressing mechanism to the first case; a motor mounting step of attaching the electric motor to the second case; a second fixing step of fixing the pawl and the ratchet gear to the second case; and an assembly step of aligning the power pin of the electric motor with the connection part of the circuit board and assembling the first case and the second case after the first fixing step, the second fixing step, and the motor mounting step.

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