An electromechanical brake for commercial vehicles with redundant fail-safe function

Abstract

The present invention discloses an electronic mechanical brake for commercial vehicles with redundant anti-failure function, including a first housing, a second housing, an energy storage mechanism, a speed reduction mechanism, a torque motor, and a brake mechanism. The energy storage mechanism includes a baffle, a spring, a first ball screw shaft, a first ball screw nut, and an electromagnetic clutch. One side of the baffle is fixedly connected to one end of the spring, the other end of the spring is fixedly connected to the inner wall of the first housing, the other side of the baffle is fixedly connected to the first ball screw nut, and the first ball screw shaft passes through the first ball screw nut, the baffle, the spring, and the electromagnetic clutch in sequence. The present invention releases elastic potential energy through the energy storage mechanism, and the potential energy is converted into kinetic energy of cam rotation through the speed reduction mechanism, the ball screw pair, and the connecting rod mechanism, thereby expanding the brake shoe, and finally causing the friction lining to press the brake drum to realize parking brake. The present invention has good braking performance, fast response speed, high reliability, and convenient modification.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle brakes, and in particular to an electronic mechanical brake for a commercial vehicle with a redundant anti-failure function. Background Art

[0002] As a new type of braking technology that is safer, more efficient and environmentally friendly, the application of automobile wire control brake technology in the whole vehicle is becoming more and more extensive. Wire control brake technology is mainly divided into electronic hydraulic brake (EHB) and electronic mechanical brake (EMB). Compared with electronic hydraulic brake, electronic mechanical brake completely abandons hydraulic components, replaces the transmission medium such as brake fluid or air in the transmission brake system with wires, and there is no brake pipeline connected in the whole system. It has the advantages of simple structure, small size, fast response speed and high control accuracy. Especially for heavy-duty semi-trailers that have corresponding delay characteristics due to the use of pneumatic brakes, the unique advantages of electronic mechanical brakes are of great significance to improving their driving stability and avoiding related accidents.

[0003] The invention patent with patent application number CN110848296A discloses an electromechanical brake, which uses a single motor as the active part and converts the rotation of the motor shaft into the linear motion of the wedge-shaped brake block through a ball screw mechanism. The structure is lightweight and highly modular, but the design of the single motor obviously does not take into account the situation of motor failure. Frequent forward and reverse rotation of the motor will increase the temperature, which will lead to a decrease in motor efficiency and damage the motor in severe cases. In addition, the invention designs a fixed brake block under the brake disc, but it does not come into contact with the brake disc during braking.

[0004] The invention patent with patent application number CN111122176A discloses a vehicle braking system and control method with brake failure redundancy function. The invention can realize functions such as brake assist and active braking of the vehicle. When one brake actuator in the dual-actuator braking system fails, the other brake can immediately intervene to complete the braking request, thereby improving the vehicle's brake redundancy safety performance. However, it still uses hydraulic braking, which has obvious disadvantages in terms of structural complexity and lightweight compared to electronic mechanical brakes that completely abandon hydraulic pipelines and brake wheel cylinders. Summary of the invention

[0005] In order to solve the problems existing in the background technology, the purpose of the present invention is to propose an electronic mechanical brake for commercial vehicles with redundant anti-failure function, which adopts dual-motor coordinated braking and a dual-degree-of-freedom multi-link mechanism, can solve the response delay characteristics of semi-trailers due to pneumatic braking, and at the same time has a certain redundant anti-failure function to ensure the braking stability of the vehicle.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: comprising a double-degree-of-freedom multi-link and a control module, characterized in that: the double-degree-of-freedom multi-link mechanism is composed of a transmission block, a brake caliper, a spring, a friction lining base, a friction lining and a brake disc. The transmission block is a triangular boss, the left end of the transmission block is hinged to the right end of the piston, the lower end of the transmission block is hinged to the lower connecting rod, the upper end of the transmission block is hinged to the upper connecting rod, the other end of the upper connecting rod is hinged to the upper end of the left brake caliper, the other end of the lower connecting rod is hinged to the right end of the right brake caliper, the left end of the left brake caliper is hinged to the fixed hinge support on the housing, and the upper end of the right brake caliper is hinged to the fixed hinge support on the housing. The lower end of the brake caliper is hinged with a friction lining base, and the brake arm and the friction lining base are limitedly connected by a spring.

[0007] Preferably, a brake disc is arranged between the left friction lining and the right friction lining, and the brake disc is fixedly mounted on the vehicle wheel hub.

[0008] Preferably, a left fixed hinge support and a right fixed hinge support are provided at one end of the shell, and a first torque motor stator is fixedly installed at the other end, the axis of the first torque motor rotor is fixedly connected to the center gear of the planetary gear system, the center gear is loosely sleeved on the ball rod shaft, the center gear is meshed with three planetary gears, the axis of the planetary gear is loosely sleeved on the outer end of the planetary gear frame, the gear frame is loosely sleeved on the ball screw shaft, the right end of the axis of the gear frame is connected to a part of the first electromagnetic clutch, the remaining part of the first electromagnetic clutch is connected to the ball screw shaft through a key, and the first torque motor is integrated with a temperature monitoring module.

[0009] Preferably, one end of the ball screw shaft is connected to the screw nut, and the other end is connected to the worm wheel through a key, the worm wheel is meshed with the worm, one end of the worm is connected to the second electromagnetic clutch, and the other end of the second electromagnetic clutch is connected to the output shaft of the second torque motor.

[0010] Preferably, the commercial vehicle electronic mechanical brake further includes a brake clearance adjustment mechanism, which includes a piston, a sealing ring, a screw nut, a ball screw shaft and a spring, wherein the piston is placed in a cylindrical groove of the housing, and the sealing ring is placed in an annular groove of the housing, with its outer ring in close contact with the housing, and its inner ring in close contact with the outer wall of the piston. The piston is connected to the screw nut via a conical surface, and the other side of the screw nut is in contact with the spring, and the other side of the spring is in contact with the housing, and the spring is always in a compressed state.

[0011] Preferably, the control module includes: a main control unit, a first torque motor control unit, and a second torque motor control unit.

[0012] Technical effects and advantages of the present invention:

[0013] 1. The present invention adopts a dual-degree-of-freedom linkage mechanism as the actuator of the brake. Each brake caliper can move independently. No matter one of the two brake calipers fails or contacts the brake disc first, the other brake arm can continue to move to achieve the braking effect. There is a certain failure redundancy function at the braking force output end.

[0014] 2. The present invention adopts a double-degree-of-freedom connecting rod mechanism as the actuator of the brake. When the brake is fault-free, the braking effect of the double-sided clamping of the friction plate can be achieved. When the same braking torque is obtained, compared with the single-sided clamping of the brake disc, the brake disc can be subjected to more uniform force and more dispersed heat, thereby making the braking performance more stable.

[0015] 3. The present invention provides the main power source for service braking by adopting a combination of a motor, a planetary gear mechanism and a ball screw mechanism. Compared with traditional hydraulic and pneumatic brakes, it simplifies the chassis structure, reduces the dead weight, and provides the possibility for a higher degree of wire control.

[0016] 4. The present invention adopts the method of installing an electromagnetic clutch between the planetary gear carrier and the ball screw shaft, and installing a temperature sensor on the main motor to monitor the temperature of the main motor in real time. When the temperature reaches the set value, the control system intervenes, closes the electromagnetic clutch, and interrupts the connection between the ball screw shaft and the planetary gear mechanism, thereby extending the service life of the motor to a certain extent.

[0017] 5. The present invention provides partial power for service braking by adopting a combination of a motor, a worm gear mechanism and a normally open electromagnetic clutch. When the main motor reaches a set temperature or fails due to a fault, the control system intervenes to close the electromagnetic clutch and transmit the torque output by the second motor to the ball screw shaft, thereby ensuring the normal movement of the brake actuator and having a certain failure redundancy function at the braking force output end.

[0018] 6. The present invention utilizes a worm gear with a self-locking function to achieve a parking brake function without installing an additional system, thereby reducing production costs and simplifying the overall structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0020] Figure 2 It is a structural schematic diagram of the double-degree-of-freedom multi-link mechanism of the present invention.

[0021] Figure 3 Schematic diagram of the dual-degree-of-freedom multi-link mechanism of the present invention.

[0022] Figure 4It is a schematic diagram of the connection structure of the ball screw pair and the piston, spring and sealing ring of the present invention.

[0023] Figure 5 It is a structural schematic diagram of the first torque motor and the planetary gear reduction mechanism of the present invention.

[0024] Figure 6 It is a structural schematic diagram of the second torque motor and the worm gear mechanism of the present invention.

[0025] The accompanying drawings are marked as: 101 housing, 102 left fixed hinge support, 103 right fixed hinge support, 201 transmission block, 202 upper connecting rod, 203 lower connecting rod, 204 left brake caliper, 205 right brake caliper, 206 left brake caliper hinge support, 207 right brake caliper hinge support, 208 left brake caliper spring, 209 right brake caliper spring, 210 left friction lining base, 211 right friction lining base, 212 left friction lining, 213 right friction lining, 3 brake disc, 4 piston, 5 sealing ring, 6 spring, 701 ball screw shaft, 702 screw nut, 801 first torque motor stator, 802 first torque motor rotor, 803 first electromagnetic clutch, 804 outer ring gear, 805 planetary gear, 806 center wheel, 807 gear rack, 901 second torque motor, 902 second electromagnetic clutch, 903 worm, 904 worm wheel. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] like Figure 1-6 As shown in the figure, the left friction lining 212 and the right friction lining 213 are respectively bonded to the front of the left friction lining base 210 and the right friction lining base 211, and the two friction lining bases are respectively hinged to the left brake caliper 204 and the right brake caliper 205 through the left brake caliper hinge support 206 and the right brake caliper hinge support 207. At the same time, the friction lining bases and the brake calipers are also connected through springs 208 and 209. The upper end of the left brake caliper 204 is connected to the right end of the upper connecting rod 202. The left end of the left brake caliper 204 is hinged to the fixed hinge support 102 on the shell 101, the right end of the upper connecting rod 202 is connected to the upper end of the transmission block 201, the right end of the right brake caliper 205 is hinged to the right end of the lower connecting rod 203, the upper end of the right brake caliper 205 is hinged to the fixed hinge support 103 on the shell 101, the left end of the lower connecting rod 203 is hinged to the lower end of the transmission block 201, and the left end of the transmission block 201 is hinged to the right end of the piston 4.

[0028] The piston 4 is placed in the through hole of the shell 101 and can move linearly along the central axis of the through hole. An annular groove is provided on the through hole. The sealing ring 5 is placed in the groove and is in close contact with the outer surface of the piston and the surface of the groove. The left end of the piston 4 is an inwardly inclined inclined surface, which can be in close contact with the outer surface of the skirt of the screw nut 702. The left end of the screw nut 702 is in contact with the right end face of the spring 6, and the left end face of the spring 6 is in contact with the shell 101. The left end of the ball screw shaft 701 is connected to the first electromagnetic clutch 803 through a key, which can transmit the rotation of the gear frame 807 to the ball screw shaft. The gear frame 807, the center wheel 806, the outer ring gear 804 and the three planetary gears 805 constitute a planetary gear reducer, wherein the center wheel 806 and the gear frame 807 are both hollowly mounted on the middle end of the ball screw shaft 701, the center wheel 806 is fixedly connected to the rotor 802 of the first torque motor, the stator 801 of the first torque motor is fixed on the housing 101, the left end of the ball screw is connected to the worm wheel 904 through a key, the worm wheel 904 is meshed with the worm 903, one end of the worm 903 is connected to the second electromagnetic clutch 902, and the other end of the second electromagnetic clutch 902 is connected to the output shaft of the second torque motor 901.

[0029] The specific implementation process of the present invention is as follows:

[0030] Service braking process:

[0031] When the driver steps on the brake pedal, the temperature sensor placed on the first torque motor will detect the temperature of the motor, and then transmit the data to the ECU for analysis and processing. If the temperature does not exceed the set danger threshold, the ECU will output a command to start the first torque motor and close the first electromagnetic clutch 803. At this time, the second electromagnetic clutch 902 is in a disconnected state, so that the torque output by the first torque motor is amplified by the planetary gear set and transmitted to the ball screw shaft 701; if the temperature exceeds the set danger threshold, the ECU will output a command to start the second torque motor 901 and close the second electromagnetic clutch. At this time, the first electromagnetic clutch 803 is in a disconnected state, and the second torque motor 901 transmits the torque to the ball screw shaft 701 through the second torque motor 902, the worm 903, and the worm wheel 904, and amplifies the torque output by the motor. The ball screw pair converts the rotation of the ball screw shaft 701 into the linear motion of the screw nut 702. The screw nut 702 pushes the piston 4, and the piston 4 further pushes the transmission block 201, driving the entire connecting rod mechanism to move so that the left friction lining 212 and the right friction lining 213 are in contact and squeezed with the brake disc 3, thereby generating braking force.

[0032] When the piston 4 makes a linear motion to the right along the center line of the through hole, it drives the transmission block 201, the upper connecting rod 202 and the lower connecting rod 203 to move together, thereby driving the left brake caliper 204 to make a counterclockwise rotational motion around the fixed hinge support 102. When the lower end of the left friction lining base 210 contacts the brake disc 3, the left friction lining base 210 will rotate clockwise around the hinge support 206 until the left friction lining 212 is in full contact with the brake disc 3, at which point the left brake caliper completely stops moving. At the same time, driven by the lower connecting rod 203, the right brake caliper 205 makes a clockwise rotational motion around the fixed hinge support 103. When the lower end of the right friction lining base 211 contacts the brake disc 3, the right friction lining base 211 will rotate counterclockwise around the hinge support 207 until the right friction lining 213 is in full contact with the brake disc 3, at which point the right brake caliper completely stops moving. Figure 3 The principle and the calculation formula of the degree of freedom of the planar mechanism: F = 3*n-2*P1-P h Calculations show that the upper connecting rod 202 and the left brake caliper 204 connected thereto move independently from the lower connecting rod 203 and the right brake caliper 205 connected thereto. If one set of rods stops moving due to damage or the friction lining contacts the brake disc first, it will not affect the other set of rods from continuing to move.

[0033] Release brake process:

[0034] When the driver releases the brake pedal, the signal collected by the brake pedal sensor is transmitted to the ECU. If the first torque motor was started before, the ECU will transmit a signal to the first torque motor to reverse the motor, and transmit the reverse torque to the ball screw shaft 701 through the planetary gear reduction mechanism and the first electromagnetic clutch 803. The entire ball screw pair performs reverse motion, so that the screw nut 702 moves linearly to the left along the through hole axis. The screw nut 702 no longer applies thrust to the piston 4. Since the sealing ring 5 undergoes elastic deformation during the braking process, the piston 4 moves linearly to the left under the action of the elastic potential energy released by the sealing ring 5, and then drives the bilateral independent brake arm mechanism to complete the reset movement, and the brake release process ends. If the second torque motor was started before, the ECU will transmit a signal to the second torque motor 901 to stop the motor, and at the same time disconnect the second electromagnetic clutch 902, interrupting the power transmission between the second torque motor 901 and the worm 903, and then the sealing ring 5 releases the elastic potential energy, driving the piston 4 to move to the left along the through hole axis, so that the bilateral independent brake arm mechanism and the ball screw pair are reset, and the brake release process ends.

[0035] Parking brake process:

[0036] When the driver presses the parking brake button, the parking brake signal is transmitted to the ECU, and then the ECU transmits a signal to the second torque motor 901 to control the motor to rotate forward, and at the same time close the second electromagnetic clutch 902. After the power output by the motor shaft is amplified and converted by the second electromagnetic clutch 902, the worm gear mechanism, the ball screw pair, and the double-degree-of-freedom multi-link mechanism, the two brake calipers are clamped inward, and finally the two friction linings are completely in contact with the brake disc 3 to generate braking force. When the braking force meets the parking brake requirements, the ECU controls the second torque motor 901 to cut off the power, and keeps the second electromagnetic clutch 902 closed. Since the selected worm gear transmission mechanism has a self-locking characteristic, it will not perform reverse transmission, and the entire mechanical structure is locked, thereby realizing the parking brake function. To release the parking brake, you only need to disconnect the second electromagnetic clutch 902, reset the ball screw pair, and the structures of the bilateral independent brake arm mechanism, and the parking brake release is completed.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A commercial vehicle electronic mechanical brake with redundant anti-failure function, comprising a dual-degree-of-freedom multi-link mechanism and a control module, characterized in that: The double-degree-of-freedom multi-link mechanism is composed of a transmission block (201), an upper link (202), a lower link (203), a left brake caliper (204), a right brake caliper (205), a left brake caliper spring (208), a right brake caliper spring (209), a left friction lining base (210), a right friction lining base (211), a left friction lining (212), a right friction lining (213) and a brake disc (3); The transmission block (201) is a triangular boss, the left end of the transmission block is hinged to the right end of the piston (4), the lower end of the transmission block is hinged to the lower connecting rod (203), the upper end of the transmission block is hinged to the upper connecting rod (202), the other end of the upper connecting rod is hinged to the upper end of the left brake caliper (204), the other end of the lower connecting rod is hinged to the right end of the right brake caliper (205), the left end of the left brake caliper (204) is hinged to the left fixed hinge support (102) on the shell, the upper end of the right brake caliper (205) is hinged to the right fixed hinge support (103) on the shell, the lower ends of the left brake caliper (204) and the right brake caliper (205) are both hinged to the left friction lining base (210) and the right friction lining base (211), and the brake caliper and the friction lining base are limitedly connected by the left brake caliper spring (208) and the right brake caliper spring (209); A left fixed hinge support (102) and a right fixed hinge support (103) are provided at one end of the housing, and a first torque motor stator (801) is fixedly installed at the other end, the axis of the first torque motor rotor (802) is connected to the center gear (806) of the planetary gear system, the center gear (806) is loosely sleeved on the ball screw shaft (701), the center gear is meshed with three planetary gears (805), the axis of the planetary gear is loosely sleeved on the outer end of the planetary gear frame (807), the gear frame is loosely sleeved on the ball screw shaft (701), the right end of the axis of the gear frame (804) is connected to a part of the first electromagnetic clutch (803), and the remaining part of the first electromagnetic clutch is connected to the ball screw shaft through a key; The first torque motor is integrated with a temperature monitoring module; The control module includes: a main control unit, a first torque motor control unit and a second torque motor control unit.

2. The commercial vehicle electronic mechanical brake with redundant anti-failure function according to claim 1, characterized in that: A brake disc (3) is arranged between the left friction lining (212) and the right friction lining (213), and the brake disc is fixedly mounted on the wheel hub of the vehicle.

3. The commercial vehicle electronic mechanical brake with redundant anti-failure function according to claim 1, characterized in that: One end of the ball screw shaft (701) is connected to the screw nut (702), and the other end is connected to the worm wheel (904) through a key. The worm wheel (904) is meshed with the worm (903). One end of the worm (903) is connected to the second electromagnetic clutch (902), and the other end of the second electromagnetic clutch (902) is connected to the output shaft of the second torque motor (901).

4. The commercial vehicle electronic mechanical brake with redundant anti-failure function according to claim 1, characterized in that: The commercial vehicle electronic mechanical brake also includes a brake clearance adjustment mechanism, which includes a piston (4), a sealing ring (5), a screw nut (702), a ball screw shaft (701) and a spring (6). The piston (4) is placed in a cylindrical groove of a housing, and the sealing ring (5) is placed in an annular groove of the housing. Its outer ring is in close contact with the housing, and its inner ring is in close contact with the outer wall of the piston (4). The piston (4) is connected to the screw nut (702) via a conical surface. The other side of the screw nut (702) is in contact with the spring (6), and the other side of the spring (6) is in contact with the housing (101). The spring (6) is always in a compressed state.

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