Back-off limiting strategy of EMB caliper, EMB caliper and vehicle

Abstract

The invention discloses a rollback limiting strategy of EMB calipers, the EMB calipers and a vehicle. The rollback limiting strategy of the EMB calipers comprises the steps that S1, a motor is controlled to rotate reversely at the target speed, and the current of the motor and the rotation angle of the motor are monitored; s2, judging whether the current of the motor and the rotation angle of the motor reach corresponding target intervals at the same time or not, if the current of the motor and the rotation angle of the motor reach the corresponding target intervals at the same time, executing the step S3, and if the current of the motor and the rotation angle of the motor do not reach the corresponding target intervals at the same time, executing the step S3; if so, executing step S4; step S3, finishing rollback; and S4, alarming abnormity. According to the rollback limiting strategy of the EMB calipers, by controlling the reverse rotation speed of the motor and monitoring the locked-rotor current and the reverse rotation angle of the motor during reverse rotation of the motor, the phenomenon that large pressure is generated between the lead screw and the piston cylinder, and jamming is generated is avoided, and a limiting pin and a stop block do not need to be arranged.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle manufacturing, and in particular to a retraction limiting strategy of an EMB caliper, an EMB caliper and a vehicle. Background Art

[0002] The relevant technology points out that the current EMB caliper is mainly composed of a motor module, a parking mechanism, a deceleration mechanism, and a transmission mechanism. During service braking, the motor output power is transmitted to the motion conversion mechanism through the deceleration mechanism to increase torque. The motion conversion mechanism converts the rotational motion into linear motion through the ball screw to push the piston cylinder. The piston cylinder pushes the friction plate to tighten the brake disc to complete the braking. When the brake is released, the motor reverses, and the piston performs a reverse linear motion based on the same principle to complete the brake release.

[0003] Under special working conditions, such as when the friction plate needs to be replaced, the piston needs to be retracted by a larger displacement to facilitate the replacement and installation of the friction plate. At this time, it is necessary to monitor the position of the piston and the lead screw to prevent the end face of the lead screw from directly contacting the inner surface of the piston cylinder (or to avoid the existence of a large pressure between the two). Otherwise, due to the friction between the two, the lead screw and the piston cylinder may be stuck. In some current designs, a limit pin is designed in the lead screw and a stop block is designed on the inner surface of the piston cylinder. The position of the two is used to realize the limit function when the piston retracts, avoiding the abnormal occurrence of the piston and the lead screw being stuck. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a retraction limit strategy for an EMB caliper, which can avoid the phenomenon of jamming between the lead screw and the piston cylinder.

[0005] The present invention also proposes an EMB caliper suitable for application of the retraction limit strategy of the above-mentioned EMB caliper.

[0006] The present invention also provides a vehicle having the EMB caliper.

[0007] The retraction limit strategy of the EMB caliper according to the first aspect of the present invention includes: step S1, controlling the motor to reverse at a target speed, and monitoring the motor current and the motor rotation angle; step S2, judging whether the motor current and the motor rotation angle reach the corresponding target interval at the same time, if the motor current and the motor rotation angle reach the corresponding target interval at the same time, executing step S3, if the motor current and the motor rotation angle do not reach the corresponding target interval at the same time, executing step S4; step S3, completing the retraction; step S4, alarming for abnormality.

[0008] According to the retraction limit strategy of the EMB caliper of the present invention, by controlling the reverse speed of the motor, monitoring the stall current and the reversal angle of the motor during reverse rotation, and controlling the contact between the end face of the screw and the inner surface of the piston cylinder to achieve physical stop, it avoids the generation of high pressure between the screw and the piston cylinder, which may cause jamming, and there is no need to set limit pins and stop blocks.

[0009] In some embodiments, before step S1 , the method further includes: step S0 , starting the motor.

[0010] The EMB caliper according to the second aspect of the present invention is suitable for the application of the retraction limit strategy of the EMB caliper of the first aspect of the present invention, and the EMB caliper includes: a motion conversion mechanism and a motor, the motion conversion mechanism is connected to the motor, the motion conversion mechanism includes: a piston cylinder, a accommodating cavity is formed in the piston cylinder, a first stop surface is formed in the accommodating cavity; a transmission shaft, the transmission shaft is arranged in the accommodating cavity; a lead screw, the lead screw is sleeved on the outside of the transmission shaft and connected to the transmission shaft, a second stop surface is formed at one end of the lead screw, and the lead screw is stopped relative to the piston cylinder through the cooperation of the first stop surface and the second stop surface.

[0011] According to the EMB caliper of the present invention, the structural design of the EMB caliper is simplified and the production cost is reduced by eliminating the additional physical limiting design of the limiting pin and the stop block. The retraction limiting strategy of the first aspect of the present invention is applied to the EMB caliper of the embodiment of the present invention, thereby ensuring the efficiency, precision and reliability of the braking process.

[0012] In some embodiments, the first stop surface extends in a direction perpendicular to the axis of the piston cylinder, the second stop surface extends in a direction perpendicular to the axis of the lead screw, and the shapes of the first stop surface and the second stop surface are adapted.

[0013] In some embodiments, the first stop surface is formed on the bottom wall of the accommodating cavity, a stop section is formed at one end of the lead screw, and the second stop surface is formed on an end surface of the stop section facing the bottom wall of the accommodating cavity.

[0014] In some embodiments, the EMB caliper also includes: a reduction mechanism and a friction plate, the motion conversion mechanism is arranged between the reduction mechanism and the friction plate, the motor is connected to the reduction mechanism, a first mating surface is formed at one end of the transmission shaft, the other end of the transmission shaft is connected to the reduction mechanism, a second mating surface is formed in the screw, and the shape of the second mating surface is adapted to the shape of the first mating surface.

[0015] In some embodiments, the first mating surface extends obliquely in the axial direction of the transmission shaft, and the first mating surface is formed as an arc surface extending along an arc line protruding outward in the radial direction of the transmission shaft, the second mating surface extends obliquely in the axial direction of the screw, and the second mating surface extends along an arc line protruding outward in the radial direction of the screw, and the first mating surface and the second mating surface are in contact with each other.

[0016] In some embodiments, a mating section is formed at one end of the transmission shaft, the first mating surface is formed on the mating section, and the first mating surface extends along the circumference of the mating section, a mating platform is formed in the lead screw, a mating groove is formed on the side surface of the mating platform facing the transmission shaft, the mating section is arranged in the mating groove, and the second mating surface is formed on the surface of the mating groove.

[0017] In some embodiments, the motion conversion mechanism also includes: a nut and a ball, the nut is fixedly connected to the piston cylinder, the nut is sleeved on the screw and can rotate relative to the screw, and the ball is arranged between the screw and the nut; and / or, the EMB caliper also includes: a parking mechanism, the parking mechanism is located between the reduction mechanism and the motor, the parking mechanism has a connecting shaft, the connecting shaft is formed with meshing teeth, the driving shaft of the motor is connected to one end of the connecting shaft, and the other end of the connecting shaft is meshingly connected to the reduction mechanism through meshing teeth.

[0018] A vehicle according to a third aspect of the present invention comprises the EMB caliper according to the second aspect of the present invention.

[0019] According to the vehicle of the present invention, the EMB caliper of the second aspect is provided, thereby improving the braking performance of the vehicle and ensuring the safety and reliability of the vehicle.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a flow chart of a retraction limit strategy of an EMB caliper according to an embodiment of the first aspect of the present invention;

[0022] Figure 2 is a schematic diagram of an EMB caliper according to an embodiment of the second aspect of the present invention;

[0023] Figure 3 yes Figure 2 Schematic diagram of the motion conversion mechanism shown in .

[0024] Reference numerals:

[0025] 100. EMB caliper; 1. speed reduction mechanism; 2. friction plate; 3. motion conversion mechanism; 31. piston cylinder; 311. first stop surface; 32. transmission shaft; 321. first matching surface; 322. boss; 33. lead screw; 331. second matching surface; 332. matching platform; 3321. connecting hole; 333. second stop surface; 34. connecting section; 35. pressure sensor; 36. gasket; 37. bearing; 38. nut; 39. ball; 4. parking mechanism; 5. motor. DETAILED DESCRIPTION

[0026] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0027] Reference below Figure 1 The retraction limit strategy of the EMB caliper according to the first embodiment of the present invention is described.

[0028] like Figure 1 As shown, the retraction limit strategy of the EMB caliper according to the first aspect of the embodiment of the present invention includes:

[0029] Step S0, turning on the motor;

[0030] Step S1, controlling the motor to reverse at a target speed, and monitoring the motor current and the motor rotation angle;

[0031] Step S2, determining whether the current of the motor and the rotation angle of the motor reach the corresponding target interval at the same time, if the current of the motor and the rotation angle of the motor reach the corresponding target interval at the same time, executing step S3, if the current of the motor and the rotation angle of the motor do not reach the corresponding target interval at the same time, executing step S4;

[0032] Step S3, complete rollback;

[0033] Step S4: abnormal alarm.

[0034] It can be understood that the motor is controlled to reverse at a low speed (target speed) and the motor current and the motor rotation angle are continuously monitored. The motor current reflects the load, and the rotation angle reflects the distance the piston moves. If the current and the rotation angle reach the corresponding target range at the same time, it means that the brake has been reset correctly and the next step can be performed. If any parameter does not reach the target range, it indicates that there may be an abnormal situation and further processing is required.

[0035] According to the retraction limit strategy of the EMB caliper in the embodiment of the present invention, by controlling the reverse speed of the motor, monitoring the stall current and the reverse angle of the motor during reverse rotation, and controlling the contact between the end face of the screw 33 and the inner surface of the piston cylinder 31 to achieve physical stop, it avoids the generation of high pressure between the screw 33 and the piston cylinder 31, which may cause jamming, and there is no need to set limit pins and stop blocks.

[0036] Reference below Figure 2-Figure 3 An EMB caliper 100 according to an embodiment of a second aspect of the present invention is described.

[0037] like Figure 2-Figure 3 As shown, the EMB caliper 100 according to the second embodiment of the present invention is suitable for the application of the retraction limit strategy of the EMB caliper 100 according to the first embodiment of the present invention. The EMB caliper 100 includes: a motion conversion mechanism 3 and a motor 5.

[0038] Specifically, the motion conversion mechanism 3 is connected to the motor 5, and the motion conversion mechanism 3 includes: a piston cylinder 31, a receiving cavity is formed in the piston cylinder 31, and a first stop surface 311 is formed in the receiving cavity; a transmission shaft 32, and the transmission shaft 32 is arranged in the receiving cavity; a screw 33, the screw 33 is sleeved on the outside of the transmission shaft 32 and connected to the transmission shaft 32, and a second stop surface 333 is formed at one end of the screw 33, and the screw 33 is stopped relative to the piston cylinder 31 through the cooperation of the first stop surface 311 and the second stop surface 333.

[0039] It is understood that the EMB (Electromechanical Brake) caliper is an advanced braking system component that uses electronic mechanical technology to achieve the braking function of the vehicle. Unlike the traditional hydraulic braking system, the EMB system uses the motor 5 to drive the mechanical structure to compress the friction plate 2 to generate braking force. This system can provide more precise control and faster response speed, and reduce maintenance requirements. The reduction mechanism 1 is used to convert the high speed and low torque of the motor 5 into the low speed and high torque required for braking, so that the power provided by the motor 5 can be effectively used to apply sufficient pressure to the brake disc. The friction plate 2 is in contact with the wheel to slow down the rotation of the wheel. When the friction plate 2 is pressed against the brake disc, friction is generated to reduce the rotation speed of the wheel until it stops. The motion conversion mechanism 3 is located between the reduction mechanism 1 and the friction plate 2, and is used to convert the linear or rotational motion generated by the reduction mechanism 1 into pressure that can push the friction plate 2 to move toward the brake disc.

[0040] That is to say, the piston cylinder 31 has a first stop surface 311, and a second stop surface 333 is formed at one end of the lead screw 33. The shape of the first stop surface 311 is adapted to the shape of the second stop surface 333. The first stop surface 311 and the second stop surface 333 ensure that the lead screw 33 will not move excessively, thereby avoiding system failure caused by excessive displacement.

[0041] According to the EMB caliper 100 of the embodiment of the present invention, the structural design of the EMB caliper 100 is simplified and the production cost is reduced by eliminating the additional physical limiting design of the limiting pin and the stop block. The retraction limiting strategy of the embodiment of the first aspect of the present invention is applied to the EMB caliper 100 of the embodiment of the present invention, thereby ensuring the efficiency, precision and reliability of the braking process.

[0042] In some embodiments of the present invention, the first stop surface 311 extends in a direction perpendicular to the axis of the piston cylinder 31, and the second stop surface 333 extends in a direction perpendicular to the axis of the lead screw 33, and the shapes of the first stop surface 311 and the second stop surface 333 are adapted. It can be understood that when the lead screw 33 rotates to a certain angle, the second stop surface 333 will contact the first stop surface 311, preventing the lead screw 33 from moving further, ensuring that the lead screw 33 will not exceed the predetermined stroke range, thereby protecting the system from overload damage.

[0043] Furthermore, a first stop surface 311 is formed on the bottom wall of the accommodating chamber, a stop section is formed at one end of the lead screw 33, and a second stop surface 333 is formed on the end surface of the stop section facing the bottom wall of the accommodating chamber. When the lead screw 33 rotates to a certain angle, the second stop surface 333 on the stop section will contact the first stop surface 311 on the bottom wall of the accommodating chamber, preventing the lead screw 33 from moving further. The shape adaptation design of the stop surface enables the lead screw 33 to stop smoothly when it contacts the stop surface, reducing the instability factor of the system under extreme conditions.

[0044] In some embodiments of the present invention, Figure 2 As shown, the EMB caliper 100 further includes: a reduction mechanism 1 and a friction plate 2, a motion conversion mechanism 3 is arranged between the reduction mechanism 1 and the friction plate 2, a motor 5 is connected to the reduction mechanism 1, a first mating surface 321 is formed at one end of the transmission shaft 32, the other end of the transmission shaft 32 is connected to the reduction mechanism 1, a second mating surface 331 is formed in the lead screw 33, and the second mating surface 331 is adapted to the shape of the first mating surface 321. Specifically, the first mating surface 321 extends obliquely in the axial direction of the transmission shaft 32, and the first mating surface 321 is formed as an arc-shaped surface extending along an arc protruding outward in the radial direction of the transmission shaft 32, the second mating surface 331 extends obliquely in the axial direction of the lead screw 33, and the second mating surface 331 extends along an arc protruding outward in the radial direction of the lead screw 33, and the first mating surface 321 and the second mating surface 331 are in contact.

[0045] That is to say, one end of the transmission shaft 32 has an arc-shaped first mating surface 321, and the other end is connected to the reduction mechanism 1. An arc-shaped second mating surface 331 is provided in the lead screw 33. The shape of the first mating surface 321 is adapted to the shape of the second mating surface 331. When the lead screw 33 is skewed due to assembly error or the gap between the lead screw 39, since the mating surface between the transmission shaft 32 and the lead screw 33 is an arc-shaped mating surface, the transmission shaft 32 can be automatically adjusted to maintain its vertical state within a certain range, and then the direction of the force received by the pressure sensor 35 is always perpendicular to the piston cylinder 31, so that the value of the pressure sensor 35 is more accurate.

[0046] In this way, through the cooperation of the arc surface between the transmission shaft 32 and the screw 33, the state of the transmission shaft 32 can be automatically adjusted and maintained within a certain range, so that the force received by the pressure sensor 35 is perpendicular to the piston cylinder 31, thereby making the data measured by the pressure sensor 35 more accurate, thereby ensuring the accuracy of vehicle status monitoring.

[0047] like Figure 3 As shown, the first mating surface 321 extends obliquely in the up-down direction and extends along an arc line protruding outward in the radial direction of the transmission shaft 32, and the second mating surface 331 extends obliquely in the up-down direction and extends along an arc line protruding outward in the radial direction of the lead screw 33. Thus, the mating mode of the first mating surface 321 and the second mating surface 331 is simple, and the arc surface is more difficult to disperse pressure than the plane, which helps to reduce the occurrence of premature wear caused by large local stress, ensures that the EMB caliper 100 can operate efficiently and reliably, and at the same time can improve the braking performance of the EMB caliper 100.

[0048] In some embodiments of the present invention, the first mating surface 321 extends obliquely in the axial direction of the transmission shaft 32, and the first mating surface 321 extends along an arc protruding outward in the radial direction of the transmission shaft 32, the second mating surface 331 extends obliquely in the axial direction of the lead screw 33, and the second mating surface 331 extends along an arc protruding outward in the radial direction of the lead screw 33, and the first mating surface 321 and the second mating surface 331 fit. In other words, the first mating surface 321 and the second mating surface 331 ensure that the force can be effectively transmitted between the transmission shaft 32 and the lead screw 33, and maintain good contact during operation. As shown in the figure, the first mating surface 321 extends obliquely in the up-down direction, and extends along an arc protruding outward in the radial direction of the transmission shaft 32, and the second mating surface 331 extends obliquely in the up-down direction, and extends along an arc protruding outward in the radial direction of the lead screw 33. Therefore, the matching method of the first matching surface 321 and the second matching surface 331 is simple, and the curved surface is more difficult to disperse pressure than the flat surface, which helps to reduce the premature wear caused by large local stress, ensuring that the EMB caliper 100 can operate efficiently and reliably, while improving the braking performance of the EMB caliper 100.

[0049] In some embodiments of the present invention, a mating section is formed at one end of the transmission shaft 32, a first mating surface 321 is formed on the mating section, and the first mating surface 321 extends along the circumference of the mating section, a mating platform 332 is formed in the lead screw 33, a mating groove is formed on the side surface of the mating platform 332 facing the transmission shaft 32, the mating section is arranged in the mating groove, and the second mating surface 331 is formed on the surface of the mating groove. It can be understood that the mating groove is used to accommodate the mating section of the transmission shaft 32, and when the mating section is placed in the mating groove, the first mating surface 321 and the second mating surface 331 are tightly fitted, thereby, the structural design of the transmission shaft 32 is reasonable, and the degree of fit between the transmission shaft 32 and the lead screw 33 is improved.

[0050] In some embodiments of the present invention, a connecting section 34 is connected to one end of the transmission shaft 32, and a connecting hole 3321 is formed on the mating platform 332. The connecting hole 3321 is formed on the bottom wall of the mating groove, and the connecting section 34 is arranged in the connecting hole 3321. In addition, a spline is formed on the peripheral wall of the connecting section 34, and the transmission shaft 32 is connected to the lead screw 33 through the spline. Thus, the spline provides a larger contact area, which can effectively transmit a higher torque. The spline structure helps to maintain a good alignment between the transmission shaft 32 and the lead screw 33, reducing the additional stress and wear caused by misalignment. The spline provides a stable connection, which is easy to disassemble and assemble, and is convenient for maintenance and replacement of parts. The spline connection can withstand a large torsional force, ensuring that the connection will not fail due to excessive torque during braking. The spline connection can also help reduce the slight movement between the transmission shaft 32 and the lead screw 33, thereby reducing vibration and noise.

[0051] In some embodiments of the present invention, a boss 322 is formed on the transmission shaft 32, the boss 322 is formed on the side of the matching section away from the connecting section 34, and is arranged adjacent to the matching section, a pressure sensor 35 is provided on the transmission shaft 32, a gasket 36 is provided between the pressure sensor 35 and the boss 322, and a bearing 37 is provided between the gasket 36 and the boss 322. It can be understood that the boss 322 is used to carry the pressure sensor 35, provides an installation position for the pressure sensor 35, the gasket 36 is provided to reduce wear, and provides necessary clearance or preload between different components, and the bearing 37 is provided to reduce relative friction between components, so as to ensure that the transmission shaft 32 can rotate smoothly.

[0052] In some embodiments of the present invention, the motion conversion mechanism 3 further includes: a nut 38 and a ball 39, the nut 38 is fixedly connected to the piston cylinder 31, the nut 38 is sleeved on the lead screw 33, and can rotate relatively with the lead screw 33, and the ball 39 is arranged between the lead screw 33 and the nut 38. It can be understood that the nut 38 is fixedly connected to the piston cylinder 31 and sleeved on the lead screw 33, the nut 38 has a spiral groove inside, the groove matches the spiral protrusion on the lead screw 33, and the ball 39 is arranged between the nut 38 and the lead screw 33 to reduce friction, improve mechanical efficiency, increase the durability and precision of the EMB caliper 100, reduce wear, and extend the service life.

[0053] In some embodiments of the present invention, the reduction mechanism 1 has an output shaft, and the other end of the transmission shaft 32 is connected to the output shaft. In this way, it is ensured that the force transmission path from the reduction mechanism 1 to the transmission shaft 32 and then to the screw 33 and the piston cylinder 31 is continuous and efficient, thereby ensuring the efficiency, precision and reliability of the entire braking process.

[0054] In some embodiments of the present invention, the EMB caliper 100 further includes: a parking mechanism 4, the parking mechanism 4 is located between the reduction mechanism 1 and the motor 5, the parking mechanism 4 has a connecting shaft, the connecting shaft is formed with meshing teeth, the driving shaft of the motor 5 is connected to one end of the connecting shaft, and the other end of the connecting shaft is meshed with the reduction mechanism 1 through the meshing teeth. It can be understood that the parking mechanism 4 is located between the reduction mechanism 1 and the motor 5 to provide additional braking force when the vehicle is parked to ensure that the vehicle does not move when it is stationary.

[0055] The vehicle according to the third aspect of the present invention comprises the EMB caliper 100 according to the second aspect of the present invention.

[0056] The vehicle according to the embodiment of the present invention is provided with the EMB caliper 100 of the second embodiment, thereby improving the braking performance of the vehicle and ensuring the safety and reliability of the vehicle.

[0057] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0058] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0059] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0060] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0061] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A retraction limit strategy for an EMB caliper, characterized in that: include: Step S1, controlling the motor to reverse at a target speed, and monitoring the motor current and the motor rotation angle; Step S2, determining whether the current of the motor and the rotation angle of the motor reach the corresponding target interval at the same time, if the current of the motor and the rotation angle of the motor reach the corresponding target interval at the same time, executing step S3, if the current of the motor and the rotation angle of the motor do not reach the corresponding target interval at the same time, executing step S4; Step S3, complete rollback; Step S4: abnormal alarm.

2. The EMB caliper retraction limit strategy according to claim 1 is characterized in that: Before step S1, the method further includes: step S0, starting the motor.

3. An EMB caliper, characterized in that: The back-off limit strategy application of the EMB caliper according to any one of claims 1 to 2, wherein the EMB caliper comprises: a motion conversion mechanism and a motor, wherein the motion conversion mechanism is connected to the motor, and wherein the motion conversion mechanism comprises: A piston cylinder, wherein a receiving cavity is formed in the piston cylinder, and a first stop surface is formed in the receiving cavity; A transmission shaft, the transmission shaft is arranged in the accommodating cavity; A lead screw is sleeved on the outside of the transmission shaft and connected to the transmission shaft, a second stop surface is formed at one end of the lead screw, and the lead screw is stopped relative to the piston cylinder through the cooperation of the first stop surface and the second stop surface.

4. The EMB caliper according to claim 3, characterized in that: The first stop surface extends in a direction perpendicular to the axis of the piston cylinder, and the second stop surface extends in a direction perpendicular to the axis of the lead screw, and the shapes of the first stop surface and the second stop surface are adapted to each other.

5. The EMB caliper according to claim 4, characterized in that: The first stop surface is formed on the bottom wall of the accommodating cavity, a stop section is formed at one end of the lead screw, and the second stop surface is formed on an end surface of the stop section facing the bottom wall of the accommodating cavity.

6. The EMB caliper according to claim 5, characterized in that: Also includes: A reduction mechanism and a friction plate, the motion conversion mechanism is arranged between the reduction mechanism and the friction plate, the motor is connected to the reduction mechanism, a first mating surface is formed at one end of the transmission shaft, the other end of the transmission shaft is connected to the reduction mechanism, a second mating surface is formed in the lead screw, and the shape of the second mating surface is adapted to the shape of the first mating surface.

7. The EMB caliper according to claim 6, characterized in that: The first mating surface extends obliquely in the axial direction of the transmission shaft, and the first mating surface is formed as an arc surface extending along an arc line protruding outward in the radial direction of the transmission shaft. The second mating surface extends obliquely in the axial direction of the screw, and the second mating surface extends along an arc line protruding outward in the radial direction of the screw. The first mating surface and the second mating surface are in contact with each other.

8. The EMB caliper according to claim 7, characterized in that: A mating section is formed at one end of the transmission shaft, the first mating surface is formed on the mating section, and the first mating surface extends along the circumference of the mating section, a mating platform is formed in the lead screw, a mating groove is formed on a side surface of the mating platform facing the transmission shaft, the mating section is arranged in the mating groove, and the second mating surface is formed on the surface of the mating groove.

9. The EMB caliper according to any one of claims 4 to 8, characterized in that: The motion conversion mechanism also includes: a nut and a ball, the nut is fixedly connected to the piston cylinder, the nut is sleeved on the lead screw and can rotate relative to the lead screw, and the ball is arranged between the lead screw and the nut; and / or, the EMB caliper also includes: a parking mechanism, the parking mechanism is located between the reduction mechanism and the motor, the parking mechanism has a connecting shaft, the connecting shaft is formed with meshing teeth, the driving shaft of the motor is connected to one end of the connecting shaft, and the other end of the connecting shaft is meshingly connected to the reduction mechanism through meshing teeth.

10. A vehicle, characterized in that: An EMB caliper comprising any one of claims 3-9.

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