A parking mechanism, an electromechanical brake, and a braking method

Abstract

The application relates to the technical field of wheel body braking, and discloses a parking mechanism, an electronic mechanical brake and a braking method, wherein the parking mechanism comprises a parking motor, a cam, a top rod and an elastic element; the parking motor is connected with the cam and is used for driving the cam to rotate; the cam is in contact with the top rod and is used for driving the top rod to move linearly; the elastic element is sleeved on the top rod and is used for elastically supporting the top rod so as to keep the top rod in contact with the cam; the top rod is provided with a bevel part, the actuator of the brake is provided with a bevel groove, the bevel part can form a wedge-shaped matching structure with the bevel groove, the wedge-shaped matching structure can guarantee that the actuator of the brake does not back off, that is, the brake block does not back off, keeps the brake clamping force, and realizes parking. The parking mechanism has stable parking braking capacity, and the parking braking is independent of the service braking; when the service braking function is invalid, the parking braking can also make the vehicle slow down and stop, plays a role of braking redundancy, and significantly improves the braking safety of the vehicle.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wheel body braking, in particular to a parking mechanism, an electronic mechanical brake and a braking method. BACKGROUND

[0002] With the development of automobile electrification, intelligentization and drive-by-wire, the electromechanical brake system develops rapidly and can make up for the shortcomings of traditional brake systems. According to the Chinese national standard GB-7258, a motor vehicle shall be provided with a brake system or device sufficient to slow down, stop and park the vehicle, and the control device of the service brake and the control device of the parking brake shall be independent of each other. The parking mechanism of the electronic mechanical brake uses the power transmission route of the locking brake to realize the parking function.

[0003] Chinese patent CN118636853A discloses an actuator integrated with parking control and an electronic mechanical brake system, which comprises a motor, a transmission mechanism, an EPB coil and a locking pin. The transmission mechanism has a transmission gear with a wave surface. The EPB coil is divided into an EPB unlocking coil and an EPB locking coil. The cooperation between the locking pin and the transmission gear with the wave surface is realized by controlling the on-off of the two coils through the circuit board, the rotation of the gear is limited, and the parking is completed. When parking brake is performed, the strength requirement of the locking pin is high, and the reliability of the parking brake is low.

[0004] Chinese patent CN116424292A discloses a parking brake device for an electronic mechanical brake system, which comprises a housing, a motor, an electromagnet assembly, a ratchet wheel and a pawl. The ratchet wheel is press-fitted on the motor shaft. The pawl is driven by the electromagnet assembly to engage with the ratchet wheel, thereby locking the motor shaft and realizing the parking function. In normal driving, the electromagnet needs to be in the energized state for a long time, which is easy to cause overheating of the electromagnet and damage the electromagnet.

[0005] The above two technical solutions rely on the service brake for parking brake, and the control device of the service brake and the control device of the parking brake are not independent of each other, resulting in poor independence and stability of the parking brake. SUMMARY

[0006] The present application provides a parking mechanism, an electronic mechanical brake and a braking method to solve the problem of poor independence and stability of the parking brake in the prior art, which can effectively improve the reliability of the parking brake and ensure parking safety.

[0007] The present application is achieved by the following technical solutions:

[0008] A parking mechanism, comprising a parking motor, a cam, a top rod and an elastic element, the parking motor is connected with the cam for driving the cam to rotate; the cam is in contact with the top rod for driving the top rod to move linearly; the elastic element is sleeved on the top rod for elastically supporting the top rod to keep the top rod in contact with the cam.

[0009] The top rod is provided with a bevel part, and the actuator of the brake is provided with a bevel groove, the bevel part can form a wedge-shaped matching structure with the bevel groove, and the actuator of the brake can be kept in the parking brake state.

[0010] Optionally, the actuator comprises a moving element for driving the brake block of the brake caliper to move, the moving element is provided with a straight groove and the bevel groove, and the brake caliper is provided with a limiting screw which can be embedded in the straight groove for limiting the rotation of the moving element.

[0011] Optionally, one side of the top rod is further provided with a limiting key groove or a limiting protrusion for matching with a corresponding limiting protrusion or limiting key groove in the mounting hole of the brake caliper to limit the rotation of the top rod.

[0012] Optionally, the elastic element is a spiral spring.

[0013] An electromechanical brake comprising the parking mechanism, further comprising a service brake motor, a parking brake motor and a transmission mechanism, the service brake motor and the parking brake motor are respectively in transmission connection with the transmission mechanism, and the transmission mechanism is in transmission connection with the actuator for driving the actuator to push the brake block to clamp the brake disc.

[0014] Optionally, the transmission mechanism comprises a service brake driving wheel, a parking brake driving wheel, a service brake driven wheel, a parking brake driven wheel and a driven wheel; the service brake driving wheel is fixed on the shaft of the service brake motor, the parking brake driving wheel is fixed on the shaft of the parking brake motor, the service brake driving wheel is in transmission connection with the service brake driven wheel, the parking brake driving wheel is in transmission connection with the parking brake driven wheel, the service brake driven wheel and the parking brake driven wheel are respectively in transmission connection with the driven wheel, and the driven wheel is connected with the actuator.

[0015] Optionally, the actuator adopts a planetary roller screw, and the nut of the planetary roller screw is connected with the moving element.

[0016] Optionally, a control unit is further included, and the control unit is connected with the service brake motor, the parking brake motor and the parking motor respectively.

[0017] A braking method based on the brake, comprising a service brake control process and a parking brake control process, and the specific steps comprise:

[0018] S101, receiving the brake control signal sent by the control unit;

[0019] S102, judging whether the received brake control signal is a service brake control signal, if yes, entering the next step, if not, entering step S112;

[0020] S103, controlling the service brake motor to eliminate the brake gap, and recording the service brake motor angle value as a;

[0021] S104, judging whether the motor angle change rate of the service brake motor is suddenly reduced, if yes, entering the next step, if not, returning to step S103;

[0022] S105, clearing the service brake motor angle value a;

[0023] S106, controlling the service brake motor angle to follow the target angle, and recording the motor angle value as b;

[0024] S107, judging whether a parking brake signal is received, if yes, entering step S112, if not, entering the next step;

[0025] S108, judging whether a brake end signal is received, if yes, entering the next step, if not, returning to step S106;

[0026] S109, controlling the service brake motor to reverse at the rated speed;

[0027] S110, judging whether the service brake motor current change rate is zero, if yes, entering the next step, if not, returning to step S109;

[0028] S111, clearing the service brake motor angle value b, controlling the service brake motor to reverse at the rated speed for a set time, and then entering step S124;

[0029] S112, reading the service brake motor angle value b under the current state;

[0030] S113, judging whether the service brake motor angle value is zero, if yes, entering the next step, if not, entering step S116;

[0031] S114, controlling the parking brake motor to rotate forward at the rated speed to eliminate the brake gap;

[0032] S115, judging whether the motor angle change rate of the parking brake motor is suddenly reduced, if yes, entering step S117, if not, returning to step S114;

[0033] S116, calculating the angle c that the parking brake motor should still rotate;

[0034] S117, control the parking brake motor angle, so that the parking brake motor angle reaches the target angle;

[0035] S118, control the parking motor to rotate, drive the cam to press down the ejector rod, and the inclined surface of the ejector rod can abut against the inclined groove of the actuator to limit the movement element of the actuator from retreating;

[0036] S119, the control unit sends a signal for the parking brake motor to reverse rotation;

[0037] S120, determine whether the reverse rotation angle of the parking brake motor is less than a critical value; if yes, proceed to the next step; if no, proceed to step S125;

[0038] S121, parking brake is completed;

[0039] S122, the parking brake motor is powered off;

[0040] S123, the parking brake state is set to "1";

[0041] S124, determine whether there is a whole vehicle power-off signal; if yes, end; if no, jump to step 101;

[0042] S125, parking brake is abnormal, and an alarm is issued;

[0043] S126, control the parking brake motor to rotate forward to compensate for the lost brake clamping force;

[0044] S127, remind the driver to perform parking brake maintenance, and then jump to step 124.

[0045] Optionally, it also includes a parking brake release control process, and the specific steps include:

[0046] S201, determine whether a parking brake release signal is received; if yes, proceed to the next step; if no, proceed to step S209;

[0047] S202, control the parking brake motor to rotate forward by a set angle, so that the movement element is released from contact with the ejector rod;

[0048] S203, control the parking motor to reverse, so that the ejector rod is reset upward under the action of the elastic element, the ejector rod is separated from the movement element, and the movement element is not limited from retreating;

[0049] S204, control the parking brake motor, apply a rated reverse voltage to the parking brake motor, so that the parking brake motor reverses at a rated speed, and the brake is released;

[0050] S205, determine whether the current change rate of the parking brake motor is zero; if yes, proceed to the next step; if no, return to step S204;

[0051] S206, control the parking brake motor to reverse at a rated speed for a set time;

[0052] S207, generate a fixed brake gap, and the parking brake release is completed;

[0053] S208, set the parking brake state to "0"; end;

[0054] S209, obtain a vehicle wheel speed sensor value;

[0055] S210, determine whether the vehicle speed in the current state is zero, if yes, jump to step S201; if no, proceed to the next step;

[0056] S211, determine whether the accelerator pedal opening is zero, if no, jump to step S202; if yes, proceed to the next step;

[0057] S212, issue an alarm, and there is a rolling vehicle;

[0058] S213, control the parking brake motor to rotate in the positive direction, and increase the parking brake clamping force;

[0059] S214, remind the driver to perform parking brake maintenance; end.

[0060] The technical scheme of the present application has at least the following beneficial effects:

[0061] The present application adopts a cam drive ejector rod to realize locking of the mobile element (roller screw nut) by a wedge-shaped structure, the wedge-shaped structure has self-locking capability, that is, when the mobile element retreats, it can be clamped tighter and tighter, and provides a detection and verification scheme for the parking brake, improving the parking brake reliability.

[0062] The parking brake of the present application does not depend on the service brake, in the prior art, generally only one drive motor (i.e. the service brake motor in the present scheme) is provided, after the drive motor reaches the parking brake clamping force, the transmission mechanism is locked by a ratchet pawl or other means, if the drive motor fails, the parking function cannot be realized. Therefore, the parking brake of the present application has better independence, thereby being able to provide stable parking brake capability.

[0063] The present application adopts a service brake motor and a parking brake motor, can realize a brake redundancy function, and whether the service brake motor and the parking brake motor are used in cooperation or the parking brake motor and the parking brake motor are used in cooperation, the parking brake function can be realized, in the case that one of the motors fails, the vehicle will not lose the most basic service and parking brake capability, improving the safety during vehicle braking. BRIEF DESCRIPTION OF DRAWINGS

[0064] Figure 1 Fig. 1 is a schematic diagram of the brake structure of the present application;

[0065] Figure 2 Fig. 2 is a schematic diagram of the exploded structure of the brake of the present application;

[0066] Figure 3 Fig. 3 is a schematic diagram of the structure of the parking mechanism of the present application;

[0067] Figure 4 Fig. 4 is a sectional view of the electromechanical brake of the present application in the un-parking brake state (the top rod is not in abutment with the sleeve);

[0068] Figure 5 Fig. 5 is a sectional view of the electromechanical brake of the present application in the parking brake state (the top rod is in abutment with the sleeve);

[0069] Figure 6 Fig. 6 is a flow chart of the driving and parking brake control of the braking method of the present application;

[0070] Figure 7 Fig. 7 is a flow chart of the un-parking brake control of the present application.

[0071] Reference signs:

[0072] 101 - housing, 111 - driving brake motor, 112 - parking brake motor, 120 - transmission mechanism, 121 - driving brake driving wheel, 122 - parking brake driving wheel, 123 - driving brake idler wheel, 124 - parking brake idler wheel, 125 - driven wheel, 131 - sleeve, 1311 - inclined slot, 1312 - straight slot, 132 - planetary roller screw, 133 - limit screw, 141 - parking motor, 142 - cam, 143 - top rod, 1430 - inclined surface part, 144 - elastic element, 200 - brake caliper, 201 - brake block, 202 - brake disc, 203 - brake support. DETAILED DESCRIPTION

[0073] With reference to Figures 1-5 The brake of the present application comprises a control unit, a housing 101, a driving brake motor 111, a parking brake motor 112, a transmission mechanism 120 and an execution mechanism, the transmission mechanism 120 amplifies the output torque of the motor, and the execution mechanism converts the rotary motion of the motor into linear motion. The brake caliper 200 is installed on the brake support 203, the driving brake motor 111 and the parking brake motor 112 are respectively in transmission connection with the transmission mechanism 120, the transmission mechanism 120 is in transmission connection with the execution mechanism, so as to drive the execution mechanism to push the brake block 201 located on the brake caliper 200 and the brake support 203 to move, so as to realize clamping the brake disc 202 to generate braking torque. The control unit can adopt conventional controller in the art. The control unit is respectively connected with the driving brake motor 111 and the parking brake motor 112 and the parking motor 141.

[0074] The transmission mechanism 120 comprises a service brake driving wheel 121, a parking brake driving wheel 122, a service brake idler wheel 123, a parking brake idler wheel 124 and a driven wheel 125; the service brake driving wheel 121 is fixed on the shaft of the service brake motor 111, the parking brake driving wheel 122 is fixed on the shaft of the parking brake motor 112, the service brake driving wheel 121 is in transmission connection with the service brake idler wheel 123, the parking brake driving wheel 122 is in transmission connection with the parking brake idler wheel 124, the service brake idler wheel 123 and the parking brake idler wheel 124 are respectively in transmission connection with the driven wheel 125, and the driven wheel 125 is connected with the execution mechanism.

[0075] The execution mechanism comprises a planetary roller screw 132 and a moving element, and the moving element is a sleeve 131 in the application; the nut of the planetary roller screw 132 is connected with the moving element, and the sleeve 131 and the nut of the planetary roller screw 132 can be fixedly connected in a welding manner.

[0076] The brake further comprises a parking mechanism, the parking mechanism comprising a parking motor 141, a cam 142, a top rod 143 and an elastic element 144, the parking motor 141 being electrically connected with the control unit; the parking motor 141 is connected with the cam 142 and is used for driving the cam 142 to rotate; the cam 142 is in contact with the top rod 143, the profile surface of the cam 142 is in contact with the upper top surface of the top rod 143, and the cam 142 is used for driving the top rod 143 to move linearly; one side of the top rod 143 is further provided with a limiting key groove or a limiting protrusion, which is used for cooperating with a corresponding limiting protrusion or limiting key groove in the mounting hole on the brake caliper 200, so as to limit the rotation of the top rod 143 and keep the top rod 143 moving on a linear path. The elastic element 144 is sleeved on the top rod 143, and the elastic element 144 is used for elastically supporting the top rod 143, so as to keep the top rod 143 in contact with the cam 142; the elastic element 144 is a spiral spring and has a certain pre-pressure during assembly, so that the top rod 143 is always pressed upward on the cam 142.

[0077] The top rod 143 is provided with a slope portion 1430, which is arranged at the bottom end surface of the top rod 143. The actuator of the brake is provided with a slope groove 1311, which is arranged on the sleeve 131 of the actuator. The slope portion 1430 of the top rod 143 can form a wedge-shaped matching structure with the slope groove 1311 of the sleeve 131. When the top rod 143 is pressed down, the sleeve 131 can be pushed to move in the direction of clamping the brake disc 202 by the brake block 201, thereby playing a locking role on the sleeve 131 after the required brake clamping force of the parking brake is reached. The sleeve 131 can also be kept in a braking state to avoid back-off. Meanwhile, the sleeve 131 is also provided with a straight groove 1312, and the brake caliper 200 is provided with a limiting screw 133 embedded in the straight groove 1312, which is used to limit the rotation of the sleeve 131, so as to ensure that the sleeve can only move linearly.

[0078] When the vehicle needs to be decelerated and stopped during driving, i.e., the service brake function is needed, the service brake motor 111 drives the service brake driving wheel 121 to rotate, the service brake driving wheel 121 drives the service brake idler wheel 123 to rotate, and the service brake idler wheel 123 drives the driven wheel 125 to rotate. The driven wheel 125 drives the planetary roller screw 132 of the actuator to move, and the sleeve 131 of the actuator moves through the nut of the planetary roller screw 132, thereby pushing the brake block 201 to move and clamping the brake disc 202 to achieve braking. When the braking is finished or the brake clamping force needs to be reduced, the service brake motor 111 can be reversed.

[0079] When the vehicle needs to be stopped for a long time or parked on a slope, i.e., the parking brake function is needed, the parking brake motor 112 drives the parking brake driving wheel 122 to rotate, the parking brake driving wheel 122 drives the parking brake idler wheel 124 to rotate, and the parking brake idler wheel 124 drives the driven wheel 125 to rotate. The driven wheel 125 drives the planetary roller screw 132 of the actuator to move, and the sleeve 131 of the actuator moves through the nut of the planetary roller screw 132, thereby pushing the brake block 201 to clamp the brake disc 202. When the brake clamping force rises to the required size of the parking brake, the parking motor 141 drives the cam 142 to rotate, so that the top rod 143 moves linearly downward, and finally the slope portion 1430 presses the slope groove 1311 to limit the backward back-off of the sleeve 131. The matching between the slope portion 1430 and the slope groove 1311 is a wedge-shaped structure, which has self-locking ability and can stably maintain the brake clamping force to achieve parking. After the slope portion 1430 and the slope groove 1311 are in abutment, it is also necessary to detect whether the top rod 143 effectively locks the sleeve 131 to improve the reliability and safety during parking.

[0080] When the vehicle needs to release the parking brake, in order to prevent the situation that the jacking rod 143 is too tightly clamped with the sleeve 131 and the jacking rod cannot be reset under the action of the elastic element 144 due to long-time parking or parking on a slope with a large angle, the parking brake motor 112 is first controlled to drive the sleeve 131 to move in a direction that makes the brake block 201 clamp the brake disc 202, so that the jacking rod 143 is loosened with the sleeve 131, then the parking motor 141 is rotated to drive the cam 142 to rotate, the jacking rod 143 is reset upward under the action of the elastic element 144, and finally the parking brake motor 112 is reversed to drive the sleeve 131 to retreat, so that the parking brake is released.

[0081] In the application, the driving brake and the parking brake are realized by using double motors, which are independent of each other and form a redundant configuration, so that when the driving brake motor 111 fails, the driving brake can be realized by the parking brake motor 112, and when the parking brake motor 112 fails, the parking brake can be realized by the driving brake motor 111, so that the safety is significantly improved; the process of the parking brake has double brake locking realized by the parking brake motor 112 and the parking motor 141, first, the parking brake controlled by the parking brake motor 112, and then the locking of the parking brake realized by the cam 142 mechanism controlled by the parking motor 141, so that the parking brake has high safety and effectively avoids the unstable factors existing in the single system brake. The application also provides a brake control method, including driving brake and parking brake control processes and a release parking brake control process.

[0082] In the application, the driving brake and the parking brake are realized by using double motors, which are independent of each other and form a redundant configuration, so that when the driving brake motor 111 fails, the driving brake can be realized by the parking brake motor 112, and when the parking brake motor 112 fails, the parking brake can be realized by the driving brake motor 111, so that the safety is significantly improved; the process of the parking brake has double brake locking realized by the parking brake motor 112 and the parking motor 141, first, the parking brake controlled by the parking brake motor 112, and then the locking of the parking brake realized by the cam 142 mechanism controlled by the parking motor 141, so that the parking brake has high safety and effectively avoids the unstable factors existing in the single system brake. The application also provides a brake control method, including driving brake and parking brake control processes and a release parking brake control process. Figure 6 , the driving brake and the parking brake control processes, and the specific steps include:

[0083] S101, receiving the brake control signal sent by the control unit;

[0084] S102, judging whether the received brake control signal is a driving brake control signal, if yes, entering the next step; if no, entering step S112;

[0085] S103, controlling the driving brake motor to eliminate the brake gap, and recording the driving brake motor rotation angle value as a, the brake gap is eliminated by inputting rated voltage to the driving brake motor, so that the driving brake motor rotates at rated speed in the positive direction, and the brake gap is eliminated at the fastest speed;

[0086] S104, judging whether the motor rotation angle change rate of the driving brake motor is suddenly reduced, if yes, it represents that the brake gap has been completely eliminated, entering the next step; if no, returning to step S103;

[0087] S105, clearing the driving brake motor rotation angle value a;

[0088] S106, control the service brake motor angle to follow the target angle, and record the motor angle value as b;

[0089] S107, determine whether the parking brake signal is received, if yes, go to step S112; if no, go to the next step;

[0090] S108, determine whether the brake end signal is received, if yes, go to the next step; if no, return to step S106;

[0091] S109, control the service brake motor to reverse at rated speed to release the brake at the fastest speed;

[0092] S110, determine whether the service brake motor current change rate is zero, if yes, it means that the sleeve and the brake caliper are just separated, go to the next step; if no, return to step S109;

[0093] S111, clear the service brake motor angle value b, control the service brake motor to reverse at rated speed for a set time, and then go to step S124;

[0094] S112, read the service brake motor angle value b under the current state;

[0095] S113, determine whether the service brake motor angle value is zero, if yes, go to the next step; if no, go to step S116;

[0096] S114, control the parking brake motor to rotate forward at rated speed to eliminate the brake gap;

[0097] S115, determine whether the motor angle change rate of the parking brake motor is suddenly reduced, if yes, go to the next step; if no, return to step S114;

[0098] S116, calculate the angle c that the parking brake motor should still rotate;

[0099] S117, control the parking brake motor angle to reach the target angle;

[0100] S118, control the parking brake motor to rotate to drive the cam to press down the jack rod, and the inclined surface part of the jack rod can abut against the inclined groove of the actuator to limit the movement element of the actuator to retreat;

[0101] S119, the control unit sends a signal for the parking brake motor to reverse rotation;

[0102] S120, determine whether the reverse rotation angle of the parking brake motor is less than a critical value; if yes, go to the next step; if no, go to step S125;

[0103] S121, parking brake is completed;

[0104] S122, parking brake motor is powered off;

[0105] S123, parking brake state is set to "1";

[0106] S124, whether there is a whole vehicle power-off signal is judged; if yes, the process is ended; if no, the process is jumped to step 101;

[0107] S125, parking brake is abnormal, and an alarm is sent out;

[0108] S126, parking brake motor is controlled to rotate forward to compensate for lost brake clamping force;

[0109] S127, the driver is reminded to carry out parking brake maintenance, and then the process is jumped to step 124.

[0110] After the parking brake is realized by locking the rotation of the parking motor, the reverse rotation signal is sent to the parking brake motor to detect whether the real locking is realized, so that the success of the parking brake is further verified, and the success rate of the parking brake is ensured.

[0111] Referring to Figure 7 , the parking brake release control process is released, and the specific steps include:

[0112] S201, whether the parking brake release signal is received is judged; if yes, the next step is entered; if no, the process is jumped to step S209;

[0113] S202, the parking brake motor is controlled to rotate forward to set an angle, so that the sleeve and the top rod are loosened and contacted;

[0114] S203, the parking brake motor is controlled to rotate reversely, the top rod is reset upward under the action of the elastic element, the top rod is separated from the sleeve, and the sleeve is retreated without limitation;

[0115] S204, the parking brake motor is controlled, the rated reverse voltage is input into the parking brake motor, the parking brake motor is reversely rotated at a rated speed, and the brake is released;

[0116] S205, whether the parking brake motor current change rate is zero is judged; if yes, the next step is entered; if no, the process is returned to step S204;

[0117] S206, the parking brake motor is controlled to reversely rotate at a rated speed for a set time;

[0118] S207, a fixed brake gap is generated, and the parking brake release is completed;

[0119] S208, the parking brake state is set to "0"; and the process is ended;

[0120] S209, acquire the vehicle wheel speed sensor value;

[0121] S210, judge whether the vehicle speed is zero under the current state, if yes, jump to step S201, if no, enter the next step;

[0122] S211, judge whether the accelerator pedal opening is zero, if no, jump to step S202, if yes, enter the next step;

[0123] S212, issue an alarm, there is a coasting;

[0124] S213, control the parking brake motor to rotate forward, increase the parking brake clamping force;

[0125] S214, remind the driver to carry out parking brake maintenance; end.

[0126] In the process of releasing the parking brake, the vehicle wheel speed and the pedal opening are detected, to ensure that the parking release is in the normal release process of human operation, rather than in the case of coasting, so as to ensure the normal implementation of the parking release.

Claims

1. An electromechanical brake comprising a parking mechanism, characterized in that, The parking mechanism comprises a parking motor, a cam, a top rod and an elastic element, the parking motor is connected with the cam and is used to drive the cam to rotate, the cam is in contact with the top rod and is used to drive the top rod to move linearly, the elastic element is sleeved on the top rod and is used to elastically support the top rod so as to keep the top rod in contact with the cam. The top rod is provided with a slope part, the actuator of the brake is provided with a slope groove, the slope part can form a wedge-shaped matching structure with the slope groove, and the actuator of the brake can be kept in the parking brake state. The electromechanical brake further comprises a service brake motor, a parking brake motor and a transmission mechanism, the service brake motor and the parking brake motor are respectively in transmission connection with the transmission mechanism, and the transmission mechanism is in transmission connection with the actuator and is used to drive the actuator to push the brake block of the brake caliper to clamp the brake disc.

2. The electromechanical brake of claim 1, wherein, The actuator comprises a moving element used to drive the brake block of the brake caliper to move, the moving element is provided with a straight groove and the slope groove, and the brake caliper is provided with a limiting screw which can be embedded in the straight groove and is used to limit the rotation of the moving element.

3. The electromechanical brake of claim 1, wherein, The top rod is further provided with a limiting key groove or a limiting protrusion on one side, which is matched with a corresponding limiting protrusion or limiting key groove in the mounting hole to limit the rotation of the top rod.

4. The electromechanical brake of claim 1, wherein, The elastic element is a spiral spring.

5. The electromechanical brake of claim 1, wherein, The transmission mechanism comprises a service brake driving wheel, a parking brake driving wheel, a service brake driven wheel, a parking brake driven wheel and a driven wheel, the service brake driving wheel is fixed on the shaft of the service brake motor, the parking brake driving wheel is fixed on the shaft of the parking brake motor, the service brake driving wheel is in transmission connection with the service brake driven wheel, the parking brake driving wheel is in transmission connection with the parking brake driven wheel, the service brake driven wheel and the parking brake driven wheel are respectively in transmission connection with the driven wheel, and the driven wheel is connected with the actuator.

6. The electromechanical brake of claim 1, wherein, The actuator adopts a planetary roller screw, and the nut of the planetary roller screw is connected with the moving element.

7. The electromechanical brake of claim 1, wherein, The control unit is further connected with the service brake motor, the parking brake motor and the parking motor.

8. A braking method based on the electromechanical brake according to any one of claims 1, 5-7, characterized by, The control process of the service brake and the parking brake comprises the following steps. S101, receiving the brake control signal sent by the control unit; S102, judging whether the received brake control signal is the service brake control signal, if yes, the next step is entered, if not, step S112 is entered; S103, controlling the service brake motor to eliminate the brake gap, and recording the service brake motor rotation angle value as a; S104, judging whether the motor rotation angle change rate of the service brake motor is suddenly reduced, if yes, the next step is entered, if not, step S103 is returned; S105, clearing the service brake motor rotation angle value a; S106, controlling the service brake motor rotation angle, so that the service brake motor rotation angle follows the target rotation angle, and recording the motor rotation angle value as b; S107, judging whether the parking brake signal is received, if yes, step S112 is entered, if not, the next step is entered; S108, judging whether the brake end signal is received, if yes, the next step is entered, if not, step S106 is returned; S109, controlling the service brake motor to reverse at the rated speed; S110, judging whether the current change rate of the service brake motor is zero, if yes, entering the next step, if not, returning to step S109; S111, clearing the service brake motor angle value b, controlling the service brake motor to reverse at the rated speed for a set time, and then entering step S124; S112, reading the service brake motor angle value b in the current state; S113, judging whether the service brake motor angle value is zero, if yes, entering the next step, if not, entering step S116; S114, controlling the parking brake motor to rotate forward at the rated speed to eliminate the brake gap; S115, judging whether the motor angle change rate of the parking brake motor is suddenly reduced, if yes, entering step S117, if not, returning to step S114; S116, calculating the angle c that the parking brake motor should still rotate; S117, controlling the parking brake motor angle to make the parking brake motor angle reach the target angle; S118, controlling the parking brake motor to rotate to drive the cam to press down the jack rod, and the inclined surface of the jack rod can abut against the inclined groove of the actuator to limit the backoff of the moving element of the actuator; S119, the control unit sends a signal for the parking brake motor to reverse rotation; S120, judging whether the reverse rotation angle of the parking brake motor is less than a threshold, if yes, entering the next step, if not, entering step S125; S121, parking brake completion; S122, parking brake motor power-off; S123, setting the parking brake state to "1"; S124, judging whether there is a whole vehicle power-off signal, if yes, ending, if not, jumping to step S101; S125, parking brake abnormality, issuing an alarm; S126, controlling the parking brake motor to rotate forward to compensate for the lost brake clamping force; S127, reminding the driver to perform parking brake maintenance, and then jumping to step S124.

9. The brake method of the electromechanical brake according to claim 8, wherein The parking brake control process also includes a parking brake release control process, and the specific steps include: S201, judging whether a parking brake release signal is received, if yes, entering the next step, if not, entering step S209; S202, controlling the parking brake motor to rotate forward by a set angle to make the moving element loose contact with the jack rod; S203, controlling the parking brake motor to reverse, and the jack rod is reset upward under the action of the elastic element to make the jack rod separate from the moving element, and the backoff of the moving element is not limited; S204, controlling the parking brake motor to input the rated reverse voltage to the parking brake motor to make the parking brake motor reverse at the rated speed to release the brake; S205, judging whether the current change rate of the parking brake motor is zero, if yes, entering the next step, if not, returning to step S204; S206, controlling the parking brake motor to reverse at the rated speed for a set time; S207, generating a fixed brake gap, and the parking brake release is completed; S208, setting the parking brake state to "0"; ending; S209, obtaining the vehicle wheel speed sensor value; S210, judging whether the vehicle speed in the current state is zero, if yes, jumping to step S201, if not, entering the next step; S211, judge whether the accelerator pedal opening is zero, if not, jump to step S202; if yes, enter the next step; S212, issue an alarm, there is a coasting; S213, control the parking brake motor forward rotation, increase the parking brake clamping force; S214, remind the driver to carry out parking brake maintenance; end.

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