Actuator for an electromechanical brake and vehicle

Abstract

The application discloses an actuator for an electromechanical brake, which comprises a brake caliper body and a drive mechanism composed of a motor and a speed reduction mechanism, the output shaft of the drive mechanism is in contact with the inner friction plate through a transmission mechanism, the transmission mechanism converts the forward and reverse rotation of the output shaft into axial extension and retraction movement, thereby providing the clamping force of the friction plate and realizing the return function, meanwhile, the outer friction plate on the other side of the brake disc moves under the sliding mechanism of the brake caliper body, and the brake and brake release actions are completed, the motor tail shaft is connected with a turbine through an electromagnetic clutch, the turbine is provided with a worm which is engaged with the turbine, the electromagnetic clutch is attracted when power is off, thereby connecting the motor tail shaft and the turbine, the electromagnetic clutch is released when power is on, thereby disconnecting the motor tail shaft and the turbine. The application can keep the position of the output shaft from rotating randomly without braking, and can ensure the necessary gap between the brake disc and the friction plate, thereby further improving the reliability and safety of the disc brake.

Description

Technical Field

[0001] This invention relates to the field of vehicle brakes, and more particularly to an actuator for an electromechanical brake and an automobile. Background Technology

[0002] Disc brake calipers have been widely used in both passenger and commercial vehicles for a long time. Currently, the force transmission medium for traditional disc brake calipers is hydraulic or pneumatic. Traditional fuel-powered vehicles use an engine to drive a hydraulic pump or air compressor, converting kinetic energy into pressure energy, which is then transmitted to the wheel-side brake calipers for braking. Traditional commercial vehicle pneumatic braking systems transmit compressor pressure to the wheels, requiring a relatively complex system of air lines, air reservoirs, and various control valves. Furthermore, the establishment and depressurization of air pressure in the lines have a certain lag time, and there are also significant noise issues. Hydraulic braking has a shorter reaction time than pneumatic braking, but it requires higher sealing of the circuit. Hydraulic braking offers advantages over pneumatic braking, such as easier operation and the ease of incorporating various optimization and adjustment devices. However, its complex structure and numerous precision components have limited its widespread use in commercial vehicles, currently primarily in passenger cars.

[0003] With the development of new energy vehicles, internal combustion engines are being replaced by electric motors. Currently, both hydraulic and pneumatic braking in new energy vehicles require electro-hydraulic pumps or electro-pneumatic compressors to convert electrical energy into pressure energy, which is then transmitted to the wheels. Simultaneously, with advancements in automotive electronics technology, the demands on vehicle braking performance are increasing, and precise braking control will be the continuous goal of automotive braking technology advancement. As technology progresses, research has begun to focus on brake-by-wire technology. Brake-by-wire technology refers to the integration of a series of intelligent control systems to achieve advanced functions, such as anti-lock braking systems (ABS), traction control systems (TCS), electronic stability control systems (ESP), and adaptive cruise control systems (ACC). The ultimate goal of brake-by-wire technology is to replace traditional pneumatic or hydraulic braking systems, and ultimately, to replace them with more advanced electronic technology. As a transitional product from traditional pneumatic or hydraulic braking systems to brake-by-wire systems, the Electro Hydraulic Brake (EHB) system emerged. Simply put, EHB replaces the traditional hydraulic control system with an electronic control system, but the brake's actuation system remains hydraulic; that is, the "hydraulic-controlled hydraulic" mode has been changed to an "electro-hydraulic" mode. Of course, similar forms can also exist for pneumatic braking systems. EHB is merely an early stage of research in brake-by-wire technology; its ultimate goal is to achieve an electromechanical braking system, or EMB. This eliminates the need for a hydraulic or pneumatic system and is a purely mechanical braking system that controls a motor via electrical signals.

[0004] EMB has significant advantages, specifically its performance characteristics are as follows: 1. By eliminating the air pipeline, braking response time is greatly reduced, effectively shortening braking distance and providing strong protection for driving safety; 2. The elimination of components such as air compressors and air tanks allows for more flexible vehicle layout; 3. The brake pedal is adjustable, with no rebound vibration, resulting in better comfort and safety; 4. All additional functions, such as ABS, TCS, ESP, ACC, etc., can be realized through the control system; 5. In the future, it can also be connected to the national traffic management system through the vehicle networking system. EMB has greater advantages in terms of braking efficiency, response time, and braking system cost. Summary of the Invention

[0005] The main objective of this invention is to provide an actuator for electromechanical brakes and an automobile, which can further improve the reliability and safety of disc brakes.

[0006] The technical solution adopted in this invention is: an actuator for an electromechanical brake, comprising a brake caliper and a drive mechanism; the brake caliper is connected to inner and outer friction pads located on both sides of the brake disc; the drive mechanism is a motor and a reduction mechanism, with an output shaft extending from the front end of the drive mechanism and a motor tail shaft extending from the end of the drive mechanism; wherein, the output shaft contacts the inner friction pad located on one side of the brake disc through a transmission mechanism; the direction of rotation of the motor to generate braking is defined as forward rotation, and the transmission mechanism converts the forward and reverse rotation of the output shaft into axial extension and retraction motion, thereby pushing or retracting the inner friction pad, while the outer friction pad on the other side of the brake disc moves under the sliding mechanism of the brake caliper, completing the braking and brake release actions;

[0007] The motor tail shaft is connected to a turbine via an electromagnetic clutch, and the turbine is equipped with a worm gear that meshes with it; wherein the electromagnetic clutch is engaged when de-energized, connecting the motor tail shaft and the turbine, and released when energized, disconnecting the motor tail shaft from the turbine.

[0008] According to the above scheme, the transmission mechanism includes a ball screw pair, the output shaft is connected to the screw shaft of the ball screw pair by a key, the screw nut of the ball screw pair is fixedly connected to or integrated with a push block, and the push block contacts the inner plate of the friction plate; an anti-rotation mechanism is provided between the push block and the inner plate of the friction plate, or between the push block and the caliper body, so as to ensure that the push block only moves along the axial direction.

[0009] According to the above scheme, the anti-rotation mechanism is a pin connecting the push block and the inner plate of the friction plate; the key is a spline; and the lead screw nut and the push block are fixedly connected by bolts.

[0010] According to the above scheme, the motor tail shaft passes through the bearing and engages with the electromagnetic clutch; the electromagnetic clutch is fixedly connected to the turbine, or integrated into a whole.

[0011] According to the above scheme, the worm gear has a hexagonal head structure for manual adjustment in case of failure.

[0012] According to the above scheme, a thrust bearing and a bushing are provided between the output shaft and the transmission mechanism.

[0013] According to the above scheme, a backup motor is connected to the tail end of the worm gear.

[0014] The control method for the actuator of the electromechanical brake, the method includes:

[0015] Braking steps: When the motor controller receives the braking command, the motor starts to rotate forward. After the motor increases the torque through the reduction mechanism, it transmits the torque to the transmission mechanism. The transmission mechanism converts the torque in the forward direction output by the output shaft into axial thrust, which pushes the inner friction pad against the brake disc. At the same time, the outer friction pad on the other side of the brake disc is pulled by the sliding mechanism of the brake caliper. The brake disc is held tightly by the clamping action of the inner and outer friction pads, thus completing the braking action.

[0016] Brake release procedure: When the motor receives the brake release command and reverses, the transmission mechanism converts the reverse motion of the output shaft into the axial motion opposite to that during braking. The friction plates and outer friction plates return to their original positions, and then the motor is de-energized.

[0017] Parking procedure: When the motor receives the parking command, it rotates to the preset angle to achieve the required parking torque. The brake disc is clamped by the inner and outer friction plates. In this state, the electromagnetic clutch is de-energized and engaged, locking the motor tail shaft through the self-locking characteristic of the worm gear. Then the motor is de-energized.

[0018] Release the parking brake procedure: The electromagnetic clutch is energized to release and unlock; the motor is energized to reverse the preset angle.

[0019] According to the above method, a backup motor is connected to the tail end of the worm gear; the method also includes an emergency braking step: when the motor of the drive mechanism fails, the backup motor is started, the electromagnetic clutch is de-energized and engaged, and through the self-locking characteristic of the worm gear, the backup motor drives the worm gear to rotate, thereby driving the worm to rotate, the worm to rotate the tail shaft of the motor, thereby driving the output shaft to rotate.

[0020] A new energy vehicle includes the aforementioned actuator for an electromechanical brake.

[0021] The beneficial effects of this invention are:

[0022] 1. By adding an electromagnetic clutch and worm gear at the end of the drive mechanism, normal braking is not affected during braking, and the output shaft position is kept from rotating arbitrarily when there is no braking, ensuring the proper clearance between the brake disc and the friction pad, and further improving the reliability and safety of the disc brake.

[0023] 2. By adding a backup motor at the end of the worm gear, when the motor of the drive mechanism fails, the backup motor drives the worm gear and motor transmission shaft to achieve emergency braking.

[0024] 3. The parking brake and parking brake release functions are achieved through the self-locking action of the electromagnetic clutch and worm gear. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0026] Figure 1 This is a cross-sectional view of an embodiment of the present invention.

[0027] In the diagram: 1-caliper body, 2-push block, 3-lead screw nut, 4-lead screw shaft, 5-thrust bearing, 6-shaft sleeve, 7-motor and reduction mechanism, 8-bearing, 9-electromagnetic clutch, 10-turbine, 11-backup motor, 12-worm gear, 13-caliper bracket, 14-brake disc, 15-outer friction plate, 16-inner friction plate. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0029] like Figure 1 As shown, the present invention provides an actuator for an electromechanical brake, including a brake caliper body and a drive mechanism; in this embodiment, the brake caliper body is a caliper body 1, which is fixed by a caliper bracket 13. Inner friction pads 16 and outer friction pads 15 located on both sides of the brake disc 14 are connected to the caliper body 1; the drive mechanism is a motor and a reduction mechanism 7, with the front end of the drive mechanism extending from the output shaft of the drive mechanism and the end end extending from the tail shaft of the motor.

[0030] The output shaft contacts the inner friction plate 16 located on one side of the brake disc 14 via a transmission mechanism. The direction of rotation of the motor to generate braking is defined as forward rotation. The transmission mechanism converts the forward and reverse rotation of the output shaft into axial extension and retraction motion, thereby pushing or retracting the inner friction plate 16. Simultaneously, the outer friction plate 15 on the other side of the brake disc 14 moves under the sliding mechanism of the brake caliper, completing the braking and brake release actions. In this embodiment, the transmission mechanism includes a ball screw pair. The output shaft is connected to the screw shaft 4 of the ball screw pair via a spline (other connection methods may also be used). The screw nut 3 of the ball screw pair is fixedly connected to or integrated with a push block 2, which contacts the inner friction plate 16. The transmission mechanism also includes an anti-rotation mechanism to prevent the push block 2 and the screw nut 3 from rotating. This mechanism is typically located between the push block and the inner friction plate, or between the push block and the caliper body, ensuring that the push block only moves axially. The ball screw assembly can also be replaced by other transmission mechanisms, such as threaded screws, wedges, crank connecting rods, worm gears, racks and pinions, eccentric wheels / cams, half-tooth springs, and other conversion mechanical structures. In this embodiment, for ease of processing, the anti-rotation mechanism is a pin connecting the push block and the inner friction plate 16, and the screw nut 3 and the push block 2 are fixedly connected by bolts; the limiting and fixing can also be done in other ways, such as direct adhesive fixing.

[0031] The motor tail shaft is connected to a turbine 10 via an electromagnetic clutch 9. The turbine 10 is equipped with a worm gear 12 that meshes with it. The electromagnetic clutch 9 engages when de-energized, connecting the motor tail shaft to the turbine 10; when energized, it disengages, disconnecting the motor tail shaft from the turbine 10. In this embodiment, the motor tail shaft passes through a bearing 8 to engage with the electromagnetic clutch 9, and the electromagnetic clutch 9 and turbine 10 are fixedly connected by a flat key. The electromagnetic clutch 9 and turbine 10 can also be integrated into a single structure.

[0032] Preferably, the worm gear 12 has a hexagonal head structure. When the vehicle is in a parked state, if the braking system cannot be released due to a malfunction, and all the wheels are locked and cannot rotate, the parking brake can be manually released by manually adjusting the hexagonal head of the worm gear 12.

[0033] Furthermore, a thrust bearing 5 and a bushing 6 are provided between the output shaft and the transmission mechanism for the cooperation between the lead screw shaft 4 (rotating part) and the caliper body 1 (non-rotating fixed part).

[0034] In this embodiment, the electromagnetic clutch 9 is a jaw-type electromagnetic clutch that engages upon power failure, but other types of electromagnetic clutches can also be used. Its function is to connect the motor shaft to the worm gear. Through power failure engagement and power failure release, it transmits the self-locking mechanism of the worm gear and the torque of the backup motor to the motor shaft. When the vehicle brakes, the electromagnetic clutch is energized and disengaged, the motor shaft disengages from the worm gear, the self-locking function is released, and the motor shaft is controlled by the motor to act on the actuator. When the brake is released, the electromagnetic clutch 9 engages upon power failure, and through the self-locking characteristic of the worm gear, it locks the motor shaft, preventing it from rotating arbitrarily during driving and affecting the proper clearance between the brake disc and friction pads.

[0035] Typically, after the vehicle's ECU issues a braking command, this command can originate from a signal emitted by the electronic brake pedal of a manned vehicle via sensors, or from a braking signal directly emitted by the vehicle's computer in an autonomous vehicle. The brake controller converts and processes the signal, then sends the control command to the motor and reduction mechanism. The actuator used in the electromechanical brake performs the braking-related processes using the following steps:

[0036] Braking steps: When the motor controller receives the braking command, the motor starts to rotate forward. After the motor increases torque through the reduction mechanism, it transmits the torque to the ball screw shaft 4. The screw nut 3 and push block 2 cannot rotate due to the limit. Under the action of the rotation of the screw shaft 4, they generate axial displacement along the screw shaft 4 towards the brake disc 14, thereby pushing the inner plate of the friction pad 16 to press against the brake disc 14. Under the sliding mechanism of the floating disc brake, the outer plate of the friction pad 15 is pulled to hold the brake disc 14 tightly, thus achieving braking. During the braking steps, the electromagnetic clutch 9 is always kept energized and released, and the motor tail shaft is disengaged from the worm gear.

[0037] Brake release procedure: When the motor controller receives the brake release command, the motor reverses, which drives the lead screw shaft 4 to reverse, and the lead screw nut 3 moves axially away from the brake disc 14 along the lead screw shaft 4 to return to its original position.

[0038] Self-locking procedure: When the motor is de-energized, the electromagnetic clutch engages, locking the motor tail shaft through the self-locking characteristic of the worm gear.

[0039] Parking procedure: When the motor controller receives the parking command, the motor rotates to the preset angle to achieve the required parking torque. The brake disc 14 is clamped by the inner friction plate 16 and the outer friction plate 15. In this state, the electromagnetic clutch 9 is de-energized and engaged. At this time, the worm gear self-locks and can no longer rotate, thus locking the motor shaft. Then the motor is de-energized, thus maintaining the torque of the output shaft of the drive mechanism and achieving parking.

[0040] Release the parking brake procedure: The electromagnetic clutch 9 is energized to release and unlock; the motor is energized to reverse the preset angle and return to the initial position.

[0041] Preferably, a backup motor is connected to the tail end of the worm gear; the method also includes an emergency braking step: when the motor of the drive mechanism fails, the backup motor is started, the electromagnetic clutch is de-energized and engaged, and through the self-locking characteristic of the worm gear, the backup motor drives the worm gear to rotate, thereby driving the worm to rotate, the worm to rotate the tail shaft of the motor, thereby driving the output shaft to rotate.

[0042] The present invention also provides a new energy vehicle that uses the aforementioned actuator for an electromechanical brake.

[0043] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. An actuator for an electromechanical brake, characterized in that, The brake caliper body and the driving mechanism are connected with the inner friction plate and the outer friction plate on both sides of the brake disc; the driving mechanism is a motor and a speed reduction mechanism, the front end of the driving mechanism extends an output shaft, and the tail end of the driving mechanism extends a motor tail shaft; wherein the output shaft is in contact with the inner friction plate on one side of the brake disc through a transmission mechanism; the direction of rotation generated by the motor during braking is defined as forward rotation, the transmission mechanism converts the forward and reverse rotation of the output shaft into axial extension and retraction movement, thereby pushing or retracting the inner friction plate, and meanwhile the outer friction plate on the other side of the brake disc moves under the sliding mechanism of the brake caliper body, so that the braking and unbraking actions are completed; The motor tail shaft is connected with a turbine through an electromagnetic clutch, the turbine is provided with a worm that is engaged with the turbine; wherein the electromagnetic clutch is energized to attract, and the connection between the motor tail shaft and the turbine is connected; the electromagnetic clutch is de-energized to release, and the connection between the motor tail shaft and the turbine is disconnected; the tail end of the worm is connected with a backup motor.

2. An actuator for an electromechanical brake according to claim 1, characterized in that, The transmission mechanism comprises a ball screw pair, the output shaft is connected with the screw shaft of the ball screw pair through a key; the screw nut of the ball screw pair is fixedly connected or integrated with a push block; the push block is in contact with the inner friction plate; a rotation stopping mechanism is arranged between the push block and the inner friction plate or between the push block and the caliper body, so as to ensure that the push block only moves in the axial direction.

3. An actuator for an electromechanical brake according to claim 2, wherein The rotation stopping mechanism is a pin connecting the push block and the inner friction plate; the key is a spline, and the screw nut and the push block are fixedly connected through bolts.

4. The actuator for an electromechanical brake of claim 1, wherein, The motor tail shaft passes through a bearing and cooperates with the electromagnetic clutch; the electromagnetic clutch is fixedly connected with the turbine, or integrated into one whole.

5. The actuator for an electromechanical brake according to claim 1 or 4, characterized in that, The worm is provided with a hexagonal head structure for manual adjustment in case of failure.

6. The actuator for an electromechanical brake of claim 1, wherein, A thrust bearing and a shaft sleeve are arranged between the output shaft and the transmission mechanism.

7. The control method for the actuator of an electromechanical brake according to any one of claims 1 to 6, characterized in that, The method comprises: The braking step: when the motor controller receives a braking instruction, the motor starts to rotate forward, the motor transmits the torque to the transmission mechanism after increasing the torque through the speed reduction mechanism, the transmission mechanism converts the torque output by the output shaft in the forward direction into axial thrust, and pushes the inner friction plate against the brake disc, while the outer friction plate on the other side of the brake disc is pulled under the sliding mechanism of the brake caliper body, the brake disc is clamped under the clamping action of the inner and outer friction plates, and the braking action is completed; The unbraking step: when the motor controller receives an unbraking instruction, the motor reverses, the transmission mechanism converts the reverse movement of the output shaft into axial movement in the opposite direction to that during braking, the inner and outer friction plates are reset, and then the motor is de-energized; The parking step: when the motor controller receives a parking instruction, the motor shaft rotates forward to a preset angle, so that the required torque for parking is reached, and the brake disc is clamped under the clamping action of the inner and outer friction plates; in this state, the electromagnetic clutch is de-energized to attract, the motor tail shaft is clamped through the self-locking characteristic of the turbine worm, and then the motor is de-energized; The unparking step: the electromagnetic clutch is energized to release the self-locking; the motor is energized to reverse the preset angle. Emergency braking step: when the motor of the driving mechanism fails, the backup motor is started, the electromagnetic clutch is attracted by power-off, and through the self-locking characteristics of the worm and worm gear, the backup motor drives the worm to rotate, thereby driving the turbine to rotate, and the turbine drives the motor tail shaft to rotate, thereby driving the output shaft to rotate.

8. A new energy vehicle, characterized in that: An actuator for an electromechanical brake according to any one of claims 1 to 6.

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