Electronic mechanical braking device

Abstract

The invention relates to a brake structure. An electronic mechanical braking device comprises a motor driving structure, a speed reducing and torque increasing structure, a linear motion structure and a braking execution structure which are sequentially connected, a piston is arranged between the linear motion structure and the braking execution structure, and one end of the piston is connected with a friction plate of the braking execution structure. An elastic element is arranged at the output end of the output piece of the linear motion structure, a pressure sensor is arranged between the elastic element and the piston, signals of the pressure sensor are transmitted to a controller, and the controller controls the motor to rotate forwards and backwards. The invention provides an electronic mechanical braking device which is simple in structure and capable of effectively preventing a motor from stalling, facilitating adjustment of braking force and achieving accurate adjustment of a brake disc. The technical problems that in the prior art, a motor mechanical braking device is prone to motor stalling, so that heating causes adverse effects on motor performance, and the braking force adjusting difficulty is increased are solved.

Description

Technical Field

[0001] The invention relates to a transmission structure, in particular to an electronic mechanical braking device. Background Art

[0002] With the continuous development of motors, batteries, and electric drive technologies, more and more wire-controlled technologies have emerged to replace traditional mechanical control technologies. The electromechanical brake (EMB) system has gradually become the first choice for the next generation of electric vehicle braking technology due to its advantages such as intelligence, lightweight, and high safety.

[0003] Compared with traditional hydraulic brakes, the EMB system adopts a mechatronics design, eliminates complex hydraulic pipelines, has a simpler structure, and is clean and environmentally friendly. Since it does not rely on brake fluid, the EMB system avoids the resulting braking delay and has a faster response speed. In addition, the EMB system can accurately control the required braking force, significantly improving the safety and reliability of the vehicle. The EMB system is mainly composed of a motor, a reducer, a clamping device, a caliper, and a controller. As a drive system, the motor will continue to rotate after the braking operation, resulting in motor stalling. When the motor stalls, not only will the heat rise rapidly, adversely affecting the motor performance, but it will also greatly increase the difficulty of adjusting the braking force. Summary of the invention

[0004] The present invention provides an electronic mechanical brake device with a simple structure, which can effectively prevent motor stalling, facilitate the adjustment of braking force, and realize precise adjustment of the brake disc; it solves the technical problem in the prior art that the motor mechanical brake device is prone to motor stalling, thereby generating heat and causing adverse effects on the motor performance, and increasing the difficulty of adjusting the braking force.

[0005] The above technical problem of the present invention is solved by the following technical solution: an electronic mechanical brake device, comprising a motor drive structure, a deceleration and torque increase structure, a linear motion structure and a brake execution structure connected in sequence, a piston is arranged between the linear motion structure and the brake execution structure, one end of the piston is connected to the friction plate of the brake execution structure, an elastic element is arranged at the output end of the output member of the linear motion structure, a pressure sensor is arranged between the elastic element and the piston, the signal of the pressure sensor is transmitted to the controller, and the controller controls the forward and reverse rotation of the motor. The drive mechanism is fixed to the brake execution mechanism by bolts, the deceleration and torque increase mechanism and the linear motion mechanism are installed inside the brake execution mechanism, and the brake execution mechanism is installed on the wheel. The linear motion structure drives the two friction plates of the brake execution structure to approach to achieve braking. After braking, due to the presence of the elastic element, the motor can still rotate, but the linear motion brought by the rotation of the motor will only compress the elastic element, and the elastic element is connected to the pressure sensor, and the pressure change can be sensed by the pressure sensor. The controller controls the motor to rotate forward or reverse by receiving the result fed back by the force sensor to adjust the deformation of the elastic element, so as to achieve the purpose of accurately adjusting the braking force. At the same time, it can also effectively prevent the motor from stalling and improve the service life of the motor. The sensor is installed between the elastic element and the piston, and can measure the final braking force acting on the brake disc, realize accurate adjustment of the braking force, and avoid inaccurate adjustment of the braking force due to the friction loss of the elastic element itself.

[0006] Preferably, the linear motion structure is a planetary roller screw structure, which includes a screw, a roller and a nut, wherein the output member is a nut, the end of the nut is connected to the elastic element, and one end of the screw is connected to the output member of the torque-increasing structure. The planetary roller screw structure can effectively convert rotational motion into linear motion, and can also effectively reduce the size of the mechanism, has a strong load-bearing capacity, and improves the overall reliability of the mechanism.

[0007] Preferably, a boss is integrally formed on the outside of the nut, and an annular groove is provided at the end of the piston. The two ends of the annular groove become the end points for limiting the axial movement of the nut. The first limiting point is the contact position between the annular groove and the boss, and its function is to ensure the initial position of the nut and the piston; the second limiting point is the rightmost end of the annular groove, and its function is to prevent the elastic element from having irreversible deformation, which causes the elastic element to fail.

[0008] Preferably, the travel of the boss in the groove is not greater than the maximum allowable deformation of the elastic element, thereby ensuring the effectiveness of the elastic element and preventing it from becoming ineffective due to excessive movement.

[0009] Preferably, the end of the lead screw outside the nut is provided with a bearing mounting surface, a thrust bearing is sleeved on the lead screw, the thrust bearing is located between the brake caliper body and the lead screw, and the end face of the thrust bearing abuts against the bearing mounting surface. The thrust bearing is used to bear the reaction force from the planetary roller screw pair.

[0010] Preferably, the elastic element is composed of a plurality of butterfly springs stacked together, and the elastic coefficient of the spring is greater than 10 3 N / mm. Due to the limited internal space of the brake, in order to meet the demand for large braking force in the brake system, the elastic element must have a high elastic coefficient. Therefore, the elastic element is preferably a plurality of butterfly springs that are superimposed or superimposed and then compounded. The butterfly springs are superimposed and then compounded. Then, under the same braking force, the total deformation of the elastic element can be multiplied. The increase in the total deformation is ultimately reflected in the number of turns of the motor. The more circles, the more beneficial it is for the control of the motor. Superposition means that multiple springs are nested with each other, and the length of the elastic element remains unchanged after superposition. Compounding means that multiple springs are axially connected, and the length of the composite spring is the length of each spring connected.

[0011] Preferably, the motor drive structure comprises a motor and an input gear.

[0012] Preferably, the deceleration and torque increase structure comprises an intermediate gear and an output gear that mesh with each other, wherein the intermediate gear meshes with the input gear in the motor drive structure, and the output gear is connected to the lead screw of the linear motion structure through internal and external splines to ensure the normal operation of the structure.

[0013] Preferably, a pressure sensor mounting groove is provided in the middle of the piston, one end of the pressure sensor is connected to the elastic element, and the pressure sensor, the elastic element and the piston are coaxially arranged.

[0014] Therefore, an electronic mechanical brake device of the present invention has the following advantages: an elastic element is provided between the nut and the piston, and the nut and the piston can move relative to each other axially. Then, during the braking process, the elastic element will produce a deformation under the action of the braking force, and the deformation will be converted into an axial displacement of the nut relative to the piston, which is finally reflected in the rotation of the motor, that is, the motor continues to rotate during the braking process and will not be blocked. A force sensor is installed between the piston and the elastic element to detect the braking force of the elastic element on the piston. The rotation-to-linear motion conversion mechanism is designed as a planetary roller screw pair, which can effectively reduce the size of the mechanism, and has a strong load-bearing capacity, thereby improving the overall reliability of the mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A cross-sectional view of an electromechanical brake device.

[0016] Figure 2This is an enlarged view of the piston and planetary roller screw structural connection.

[0017] Figure 3 This is an enlarged view of the fit between the piston and the nut. DETAILED DESCRIPTION

[0018] The technical solution of the invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0019] Embodiment 1: like Figure 1 and 2 As shown in Figure 3, an electronic mechanical brake device includes an end cover 3 and a brake caliper body 16. The end cover 3 and the brake caliper body 16 form an accommodating chamber, in which a motor drive structure is installed, the motor drive structure is connected to a deceleration and torque increase structure, the deceleration and torque increase structure is connected to a linear motion structure, and the linear motion structure is connected to a brake execution structure. A piston 13 and an elastic element 14 are installed between the linear motion structure and the brake execution structure, and a coaxially arranged pressure sensor 15 is provided at the center of the piston 13.

[0020] The motor driving structure includes a driving motor 1 , and an input gear 2 is sleeved on the output shaft of the driving motor 1 .

[0021] The speed reduction and torque increase structure comprises an intermediate gear 4 and an output gear 5 which are meshed with each other, wherein the intermediate gear 4 is meshed with the input gear 2 in the motor drive structure.

[0022] The linear motion structure is a planetary roller screw structure, which includes a screw 6 located in the center, and the output gear 5 is connected to the screw of the linear motion structure through an inner and outer spline 21. There are rollers 11 outside the screw 6, and nuts 12 are connected to the outer surface of the rollers 11. An inner gear ring 9, a retainer 10 and a retaining spring are installed at both ends of the roller 11. The roller 11 and the nut 12, and the roller 11 and the screw 6 are meshed through a threaded pair; the inner gear ring 9 is placed at both ends of the nut 12 and meshes with the gears at both ends of the roller 11; the retainer 10 is installed on one side of the inner gear ring 9, and is processed with the same number of positioning holes as the rollers to ensure that the rollers do not deflect during the movement; the retaining spring is on the outside of the retainer to prevent the retainer from axial movement. The part of the screw 6 located outside the nut 12 is processed with a bearing mounting surface 8, and a thrust bearing 7 is sleeved on the screw 6. The thrust bearing 7 is installed between the screw 6 and the brake caliper body 16 to withstand the reaction force from the planetary roller screw pair. The end of the lead screw is connected to the output gear 5 via a spline 21 .

[0023] An annular protrusion 22 is formed on the outer circumferential surface of the nut 12. A groove 23 is formed at the end of the piston 13. The outer diameter of the protrusion 22 is smaller than the inner diameter of the groove 23. The two ends of the groove 23 are the starting point and the end point of the protrusion movement. The movement stroke of the nut 12 is L, which is smaller than the value of the maximum allowable deformation of the elastic element 14.

[0024] The end of the nut 12 is abutted with a plurality of butterfly spring composite elastic elements 14, one end of the elastic element 14 abuts against the end surface of the nut 12, and the other end of the elastic element 14 abuts against the pressure sensor 15. The elastic coefficient of the elastic element 14 is greater than 10 3 N / mm.

[0025] The brake execution structure includes a left friction plate 18, a right friction plate 17 and a brake caliper body 16. The piston 13 is connected to the left friction plate 18. A rectangular sealing ring 20 and a dustproof sealing ring 19 are connected to the outer sleeve of the piston 13.

[0026] Working principle: Vehicle braking can be divided into three stages. The first stage: the clearance of the brake device is eliminated; the controller receives the braking command, the motor starts to rotate, and the torque and speed output by the motor are transmitted to the linear motion structure through the deceleration and torque increase mechanism. Under the action of the planetary ball screw pair, the left friction plate is pushed to move axially in the direction of the brake disc. When the left friction plate contacts the brake disc, the brake caliper body begins to move axially until the friction plates on both sides are close to the brake disc, and the brake assembly clearance is completely eliminated. In this process, only the friction force inside the mechanism needs to be overcome, and the elastic element is formed by the combination or superposition of multiple butterfly springs with high elastic coefficients, so there is almost no relative axial displacement between the nut and the piston.

[0027] The second stage: braking process; when the gap of the braking device is completely eliminated, the vehicle begins to enter the braking deceleration stage, the motor continues to work, and the output torque is transmitted to the piston through the deceleration and torque-increasing mechanism. At this time, since the friction plate is already close to the brake disc, the piston does not move linearly. In the existing scheme, the motor begins to stall, and the magnitude of the braking force can only be adjusted by adjusting the current of the motor, but this method has low adjustment accuracy, and the stalling will have an adverse effect on the performance of the motor. In this application, a pressure sensor and an elastic element are designed between the piston and the nut, and the axial movement of the nut principle piston end is limited by designing the protrusion on the nut and the groove on the piston. The nut can also move axially close to the piston end. In this process, the screw rod rotates through the external spline at one end and the internal spline of the output gear of the deceleration and torque-increasing mechanism. The torque transmitted from the motor end is converted into thrust through the planetary roller screw pair. The nut transmits the thrust to the elastic element, and the elastic element acts on the pressure sensor and the piston, and finally realizes the braking process. When the force is transmitted to the elastic element, the elastic element will deform, so the nut will move linearly close to the piston end, that is, the motor does not need to be stalled and keeps rotating. When the braking force needs to be adjusted, the pressure sensor detects the force acting on the piston and feeds back to the controller. The controller follows the braking force target to control the motor to rotate forward or reverse, and finally adjusts the braking force by adjusting the deformation of the elastic element. The force transmission route of the braking process is: torque output by the motor → deceleration and torque increase mechanism → planetary roller screw pair → elastic element → pressure sensor, piston → friction plate → brake disc.

[0028] The third stage: the brake release stage; when the vehicle completes the braking purpose, the motor reverses, and the speed reduction and torque increase mechanism drives the lead screw to reverse, the nut moves axially away from the piston end, and the elastic element returns to its original state. When the nut moves to the end of the groove of the piston, the piston assembly moves away from the friction plate, the friction plate moves away from the brake disc, and the brake is released.

[0029] The specific embodiments described herein are merely examples of the concept of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. An electronic mechanical brake device, comprising a motor drive structure, a deceleration and torque increase structure, a linear motion structure and a brake execution structure connected in sequence, characterized in that: A piston is provided between the linear motion structure and the brake execution structure, one end of the piston is connected to the friction plate of the brake execution structure, an elastic element is provided at the output end of the output member of the linear motion structure, a pressure sensor is provided between the elastic element and the piston, the signal of the pressure sensor is transmitted to the controller, and the controller controls the forward and reverse rotation of the motor.

2. An electromechanical brake device according to claim 1, characterized in that: The linear motion structure is a planetary roller screw structure, which includes a screw, a roller and a nut, wherein the output member is a nut, the end of the nut is connected to the elastic element, and one end of the screw is connected to the output member of the torque-increasing structure.

3. An electromechanical brake device according to claim 2, characterized in that: A boss is integrally formed on the outside of the nut, and an annular groove is provided on the end of the piston.

4. An electromechanical brake device according to claim 3, characterized in that: The movement stroke of the boss in the groove is not greater than the value of the maximum allowable deformation of the elastic element.

5. An electromechanical brake device according to claim 2, characterized in that: The end of the lead screw outside the nut is provided with a bearing mounting surface, a thrust bearing is sleeved on the lead screw, the thrust bearing is located between the brake caliper body and the lead screw, and the end face of the thrust bearing abuts against the bearing mounting surface.

6. An electromechanical brake device according to any one of claims 1 to 5, characterized in that: The elastic element is composed of a plurality of butterfly springs stacked together, and the elastic coefficient of the spring is greater than 10 3 N / mm.

7. An electromechanical brake device according to any one of claims 1 to 5, characterized in that: The motor driving structure comprises a motor and an input gear.

8. An electromechanical brake device according to any one of claims 1 to 5, characterized in that: The deceleration and torque-increasing structure comprises an intermediate gear and an output gear that mesh with each other, wherein the intermediate gear meshes with the input gear in the motor drive structure, and the output gear is connected to the lead screw of the linear motion structure through internal and external splines.

9. An electromechanical brake device according to any one of claims 1 to 5, characterized in that: A pressure sensor mounting groove is arranged in the middle of the piston, one end of the pressure sensor is connected to the elastic element, and the pressure sensor, the elastic element and the piston are coaxially arranged.

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