Mechanical decoupling drive-by-wire brake and braking system

Abstract

The invention relates to a mechanical decoupling drive-by-wire brake and a brake system. The mechanical decoupling drive-by-wire brake comprises a motor power-assisted mechanism, a pedal actuating mechanism, a mechanical decoupling mechanism, a hydraulic establishing mechanism, a brake wheel cylinder mechanism and a brake structural part. In the on-line control braking process, a braking control system controls a braking motor to rotate, speed reduction and torque increase of the braking motor are achieved through a first-stage driving gear, an intermediate shaft gear combination and a gear nut, rotating motion of a large gear is converted into translational motion of a lead screw, a holder, a push rod connector, a rubber gasket, a main cylinder push rod base and a large spring base are pushed, a large spring is compressed, and the braking motor is driven to rotate. A master cylinder push rod is pushed, pressure building is conducted on a brake master cylinder, the brake master cylinder is connected with brake calipers through a brake pipeline, and braking is achieved through the brake calipers; the lead screw and the hollow push rod are not mechanically connected in the axial direction, in the braking process, translation of the lead screw does not drive the hollow push rod to advance, and therefore the brake pedal does not follow up in the braking process, and mechanical decoupling is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile brake-by-wire technology, and in particular to a mechanically decoupled brake-by-wire and a braking system. Background Art

[0002] In recent years, with the increasing prominence of energy crises, environmental pollution, and rising temperatures, the air pollution and energy consumption caused by traditional fuel vehicles have become unavoidable challenges. This has led to a growing share of electric vehicle production and sales. my country's new energy vehicle industry has experienced rapid development, now leading the world in scale. Electric vehicles are placing new demands on braking systems. On the one hand, they demand decoupling of pedal force and wheel braking force, maintaining good pedal feel and enabling regenerative braking. On the other hand, they demand active braking capabilities to accommodate intelligent driver assistance systems such as emergency braking. Whether it's effective coordinated control of motor regenerative braking and the braking system during regenerative braking, or the new demands placed on braking systems by the development of intelligent vehicles, decoupling of manual braking force is essential. Traditional braking systems cannot meet the braking force requirements of regenerative braking and autonomous driving technologies. Furthermore, manual braking force is coupled, and when certain active safety systems engage the brakes, pedal judder, significant vibration, and noise can occur, resulting in poor braking comfort. As the future development direction of automotive braking systems, brake-by-wire systems use electric motors to replace vacuum boosters and electronic components to replace some mechanical elements in traditional braking systems. This system can meet the current requirements of automotive braking systems and bring new opportunities for the rapid development of automotive braking. In summary, the research on brake-by-wire systems, especially mechanically decoupled brake-by-wire structures and control theories, conforms to the inevitable development trend of the current automotive industry.

[0003] For example, prior art patent CN206579621 discloses a fully mechanically decoupled brake-by-wire system for automobiles. This system uses a motor, an electromagnetic rotary relay, and a mechanical decoupling mechanism to push the master cylinder piston, generating hydraulic pressure. When the electromagnetic rotary relay is deenergized and the electromagnetic rotary member drives the decoupling push rod back to its original position, the front end of the decoupling push rod cannot pass through the relay housing, while a spring baffle can freely pass through the front end of the push rod barrel, achieving mechanical decoupling. However, the metal components can collide with each other, resulting in high noise and frequent collisions.

[0004] Prior art 2, the invention patent with application number CN104071142A, discloses a wire-controlled brake system, which replaces the traditional vacuum booster with an electric motor. Through the coordinated work of the motor, planetary gear reduction mechanism and high-pressure accumulator, the piston in the brake master cylinder is pushed to generate brake hydraulic pressure. However, the system adds a high-power drive motor to store energy in the high-pressure accumulator, which increases the system energy consumption.

[0005] Prior art three, patent application number CN104760586A, discloses a dual-motor brake-by-wire system. It uses one motor and ball screw mechanism to push the master cylinder piston, generating hydraulic pressure; another motor and ball screw mechanism provides active pedal feel for the brake pedal. However, this system uses two motor-ball screw mechanisms and two master cylinders, resulting in a complex structure and high manufacturing costs.

[0006] In summary, while current mainstream brake-by-wire systems offer overwhelming advantages over traditional brakes, they suffer from complex component designs, high noise levels, frequent collisions, high energy consumption, and manufacturing costs, as well as a lack of mechanical decoupling between the leadscrew and the brake pedal. Given the current trend toward low-cost, safe, and reliable brakes, coupled with the declining prices of new energy vehicles, the market demands a more cost-effective brake-by-wire system that can achieve mechanical decoupling. Summary of the Invention

[0007] In view of the above problems, the purpose of the present invention is to propose a wire-controlled brake and braking system that can achieve mechanical decoupling with simple component structure design, low cost, low energy consumption, low noise, and collision resistance.

[0008] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solution: a mechanically decoupled wire-controlled brake and braking system, characterized in that it includes a motor assist mechanism (1), a pedal actuation mechanism (2), a mechanical decoupling mechanism (3), a hydraulic establishment mechanism (4), a brake wheel cylinder mechanism (5), a brake control system (6), and a brake structural component (7).

[0009] The motor assist mechanism (1) comprises: a brake motor (101), a first-stage driving gear (102), an intermediate shaft input gear (103), an intermediate shaft output gear (104), a gear nut (105), a large bearing (106), a bearing sleeve (107), a lead screw (108), a retaining frame (109), a guide block (110), an intermediate shaft (111), a guide column (112), a short threaded column (113), and a limit nut (114), so as to realize the deceleration and torque increase of the brake motor (101) and convert the rotational motion of the brake motor (101) into the translational motion of the lead screw (108).

[0010] The pedal actuating mechanism (2) comprises a brake pedal (201), a lifting lug (202), a pedal push rod (203), a hollow push rod (204), and a small spring (205), and is used for mechanical backup braking.

[0011] The mechanical decoupling mechanism (3) comprises: a push rod joint (301), a rubber gasket (302), a master cylinder push rod seat (303), a large spring seat (304), a large spring (305), and a master cylinder push rod (306), so as to achieve mechanical decoupling.

[0012] The hydraulic pressure building mechanism (4) includes: a brake master cylinder (401), a large oil storage tank (not shown), a small oil storage tank (402), a bypass hole (403), and a master cylinder piston (404) to build and transmit brake fluid pressure.

[0013] The wheel brake cylinder mechanism (5) comprises a brake pipe (501) and a brake caliper (502) for clamping a brake disc to brake the vehicle.

[0014] The braking control system (6) includes a braking controller housing (601), a signal processing chip (not shown), a motor control unit (not shown), a pedal opening sensor (602), and a wheel speed sensor (603) to control the braking system according to vehicle information.

[0015] The brake structure (7) comprises: a brake front housing (701), a buffer gasket (702), a F-shaped cover (703), a dust cover (704), a fixing nut (705), an E-shaped retaining ring (706), a metal tie (707), a brake rear housing (708), a gear cavity (709), and a screw cavity (710) for fixing and installing the parts of the entire brake.

[0016] The gears in the motor assist mechanism (1) are all helical gears, and the materials of all gears are wear-resistant plastics. The output shaft of the brake motor (101) is connected to the input end of the first-stage driving gear (102), and the output end of the first-stage driving gear (102) is meshed with the intermediate shaft input gear (103). The intermediate shaft output gear (104) and the intermediate shaft input gear (103) are made into an integrated part and fixed on the intermediate shaft (111) through a small bearing. The gear nut (105) is meshed with the intermediate shaft output gear (104). The nut (105) is an integrated part made of a screw nut (10502) and a large gear (10501). The internal thread of the screw nut (10502) is engaged with the screw (108). The bearing sleeve (107) and the gear nut (105) are injection-molded into an integrated assembly. When the bearing (106) is placed on it, a spinning process is used to turn the bearing sleeve (107) over and fix the bearing (106). The inner ring of the bearing (106) is interference-fitted with the optical axis part of the screw nut (10502), and the outer ring is clearance-fitted with the brake front housing (701). The lead screw (108) and the retaining frame (109) are welded together, and the retaining frame (109) moves with the movement of the lead screw (108). The lead screw (108) and the push rod joint (301) are clearance-matched (802), and there is a gap between the inner ring of the lead screw (108) and the outer ring of the hollow push rod (204). The retaining frame (109) and the guide block (110) are fixed together with an E-shaped retaining spring (706). The guide block (110) and the guide column (112) are clearance-matched to reduce friction resistance during sliding. The guide block (110) moves on the guide column (112) to guide the retaining frame (109) to move axially along the lead screw nut (10502) to prevent the lead screw (108) from rotating. The limiting nut (114) and the guide column (112) are threadedly matched. During the braking process, the limiting nut (114) on the guide column (112) blocks the guide block (110) to limit the stroke of the lead screw (108), ensuring that the master cylinder piston (404) does not collide with the inner wall of the brake master cylinder (401). The short threaded columns (113) are a pair, respectively located on both sides of the guide column (112) and arranged symmetrically, and are used together with the guide column (112) to fix the brake on the vehicle.

[0017] The brake pedal (201) in the pedal actuating mechanism (2) is connected to the pedal push rod (203) via a lifting lug (202). The pedal force acting on the brake pedal (201) serves as a power source for the braking force during mechanical backup braking. The lifting lug (202) is threadedly connected to the pedal push rod (203). The pedal push rod (203) is ball-jointed to the hollow push rod (204), which provides flexible and accurate control and a large torsion angle. The hollow push rod (204) has no axial mechanical connection with the lead screw (108). A gap exists between the small spring (205) and the inner wall of the hollow push rod (204), and one end of the small spring presses against the inner end surface of the hollow push rod (204) and the other end presses against the master cylinder push rod seat (303). The small spring is compressed when the driver steps on the brake pedal (201).

[0018] The push rod joint (301) in the mechanical decoupling mechanism (3) is clearance-matched (802) with the lead screw (108), and the end face of the semi-enclosed opening (30101) contacts the retaining frame (109). During wire-controlled braking, the push rod joint (301) is pushed by the retaining frame (109). The rubber gasket (302) is between the push rod joint (301) and the master cylinder push rod seat (303), and can play a buffering role to prevent the push rod joint (301) and the master cylinder push rod seat (303) from directly colliding. The master cylinder push rod seat (303) contacts the large spring seat (304) and is spherically connected to the master cylinder push rod (306). During braking, the master cylinder push rod (306) is pushed. 6), the large spring seat (304) cooperates with the axial hole of the push rod joint (301), and the radial boss (30104) on the end tooth of the push rod joint will limit the large spring seat (304). One end of the large spring (305) is pressed against the large spring seat (304), and the other end is pressed against the brake rear shell (708). When braking, it is compressed by the large spring seat (304). When braking ends, the large spring seat (304) will rebound back to its original position. One end of the master cylinder push rod (306) is connected to the master cylinder push rod seat (303) by a ball joint, and the other end is pressed against the brake master cylinder (401). During the braking process, the master cylinder piston (404) is pushed to establish hydraulic pressure on the brake master cylinder (401).

[0019] The front end of the brake master cylinder (401) in the hydraulic establishment mechanism (4) is supported by the master cylinder push rod (306), and the rear end is fixedly mounted on the brake rear housing (708) by a fixing nut (705). The small oil storage tank (402) is mounted on the upper end of the brake master cylinder (401), and the large oil storage tank (not shown in the figure) is connected to the small oil storage tank (402) through an oil pipe. There are two bypass holes (403) on the side of the brake master cylinder (401), and the bypass holes (403) are connected to the brake pipeline (501) to transfer pump fluid to the brake caliper (502).

[0020] The brake line (501) in the brake wheel cylinder mechanism (5) is connected to the bypass hole (403) of the master cylinder; the brake line (501) is divided into a first brake line (50101) and a second brake line (50102), the first brake line (50101) is connected to the left front wheel brake caliper (50201) and the right front wheel brake caliper (50202), and the second brake line (50102) is connected to the left rear wheel brake caliper (50203) and the right rear wheel brake caliper (50204), and the pump fluid of the brake master cylinder (401) is transferred to the brake caliper (502) to achieve braking.

[0021] The signal processing chip, the motor control unit and the brake motor (101) in the brake control system (6) are installed in a brake controller housing (601). The pedal opening sensor (602) is installed on the brake pedal (201) to estimate the position of the pedal push rod (203) and then send a switch signal to the signal processing chip. The signal processing chip performs a pre-brake position estimation based on the position estimation of the pedal push rod (203) by the pedal opening sensor (602). There are four wheel speed sensors (603), which are respectively installed on four brake calipers (502) to detect the wheel speed of the vehicle when it is traveling.

[0022] The brake front shell (701) and the brake rear shell (708) in the brake structure (7) are connected by bolts, and all parts are installed therein. The buffer gasket (702) is limited by the limiting column (70102) of the brake front shell (701). The polygonal cover (703) covers the brake front shell (701) and is fixed by the front shell fixing groove (70102) to prevent the hollow push rod (204) from rebounding and popping out of the brake front shell (701) after braking. The dust cover (704) is sleeved on the brake front shell (701) and is tied and fixed with a metal tie (707). The gear cavity (709) is a cavity between the brake front shell (701) and the brake rear shell (708). The screw cavity (710) is a cavity composed of the screw (108), the hollow push rod (204) and the push rod joint (301).

[0023] The materials of the brake motor (101), the lead screw (108), the retaining frame (109), the intermediate shaft (111), the guide column (112), the short threaded column (113), the pedal push rod (203), the hollow push rod (204), the large spring seat (304), the fixing nut (705), the E-shaped retaining ring (706), and the metal tie (707) are all metal materials.

[0024] The hollow push rod (204) is in the shape of a cylinder (20401) with a hollow interior and a closed boss (20402) at the front end. The closed boss (20402) has a spherical groove (20403) which can be connected to the pedal push rod (203) by a ball joint. The front end surface (20404) is evenly distributed with four circular axial air holes (20406). The front end side surface (20405) is also evenly opened with four semicircular radial air holes (20407) which cross-connect with the four circular axial air holes (20406) on the front end surface (20404), which can reduce the resistance caused by air pressure during braking. The invention can improve the force, improve the efficiency and reduce the energy consumption. When the automatic braking is performed, the space of the screw cavity (710) becomes larger and the air pressure becomes smaller. At this time, the semicircular radial air vent (20407) on the front side surface (20405) of the hollow push rod (204) and the circular axial air vent (20406) on the front end surface (20404) are used to suck air into the dust cover (704) to increase the air pressure. When the mechanical backup braking is performed, the volume of the screw cavity (710) becomes smaller and the air pressure becomes larger. The internal gas is discharged to the dust cover (704) outside through the circular axial air vent (20406) on the front end surface (20404) of the hollow push rod (204) to reduce the air pressure. During the line control braking process, the lead screw (108) and the hollow push rod (204) have no mechanical connection in the axial direction, the translation of the lead screw (108) will not drive the translation of the hollow push rod (204), and the brake pedal (201) will not follow the movement of the lead screw (108) during braking, thereby realizing mechanical decoupling of the movement between the lead screw (108) and the brake pedal (201). In the case of mechanical backup braking, the hollow push rod (204) is separated from the lead screw (108) and moves with the pedal push rod (203).

[0025] One end of the push rod joint (301) is a semi-closed opening (30101), and the other end is a toothed opening (30102). The bottom is a cylinder (30107). There are 6 end teeth (30103) on the cylinder (30107) and each has a radial boss (30104), which can limit the large spring seat (304). The semi-closed end of the push rod joint has a stepped groove (30106), which is composed of two inner ring surfaces and two grooves, and a groove is opened behind each inner ring surface. The lower inner ring surface (3010601) is used to limit the screw (108), and the lower groove (3010602) is opened at the back to make the screw (108) and the push rod joint (301) fit with each other (802). The lower groove (3010602) is followed by an upper inner ring surface (3010603) for the hollow The push rod (204) is limited, and an upper groove (3010604) is opened behind the upper inner ring surface (3010603) so that the hollow push rod (204) and the push rod joint (301) are clearance-matched. The inner end surface (3010605) is opened below the upper groove (3010604). Four semicircular end surface air vents (30105) are evenly opened along the end surface at the bottom of the push rod joint (301). During automatic braking, the space of the screw cavity (710) becomes atmospheric pressure and decreases. Air is sucked into the gear cavity (709) through the semicircular end surface air vents (30105) of the push rod joint (301) to increase air pressure. During mechanical backup braking, the volume of the screw cavity (710) decreases and the air pressure increases. The internal gas is discharged to the gear cavity (709) through the semicircular end surface air vents (30105) of the push rod joint (301) to reduce air pressure.

[0026] The gear nut (105) is an integrated assembly of a screw nut (10502), a large gear (10501) and a bearing sleeve (107), and has a simple processing technology, low cost, high strength and long service life.

[0027] The front outer ring surface (70101) of the front shell (701) is provided with four evenly distributed fixing grooves (70102) for fixing the shaped cover (703). The front end surface (70103) of the front shell is provided with four evenly distributed limiting posts (70104) for limiting the buffer gasket (702). The buffer gasket (702) is provided with four evenly distributed limiting holes (70201) for cooperating with the hole axis of the limiting posts (70104) of the front shell. The buffer gasket (702) can prevent the hollow push rod (204) and the shaped cover (703) from being displaced. Direct collision plays the role of reducing impact force and reducing noise. The F-shaped cover (703) is sleeved on the cylindrical end (70105) of the front shell. By changing the shape of the open end (70301) of the F-shaped cover (703), it is fixed on the cylindrical end (70105) of the front shell. The closed boss (20402) of the hollow push rod (204) is axially limited (803) on the inner side surface of the semi-sealed end (70302) of the F-shaped cover (703) to prevent the hollow push rod (204) from rebounding and popping out of the brake front shell (701) when braking is completed.

[0028] The screw (108) and the push rod joint (301) are clearance-matched (802), and the screw (108) and the retaining frame (109) are welded together. The retaining frame (109) pushes the push rod joint (301), the rubber gasket (302), the master cylinder push rod seat (303), the large spring seat (304), and the master cylinder push rod (306), and then pushes the brake master cylinder (401) to establish hydraulic pressure. The lower groove annular surface (30106) of the step groove (30106) of the push rod joint (301) is 1060201) forms an annular surface clearance fit (80201) with the outer annular surface (10802) of the lead screw (108) extending out of the ring (10801), and the lower groove end surface (301060202) of the step groove (30106) of the push rod joint (301) forms an end surface clearance fit (80202) with the outer end surface (10803) of the lead screw (108) extending out of the ring (10801), thereby avoiding collision between the lead screw (108) and the push rod joint (301) during braking.

[0029] The mechanical decoupling wire control brake is configured such that, in the case of automatic braking, the brake motor (101) is directly controlled by the brake control system (6), the hydraulic pressure building mechanism (4) is built up through the motor assist mechanism (1) and the mechanical decoupling mechanism (3), and the brake caliper (502) is driven to brake through the brake wheel cylinder mechanism (5). In the case of driver operation, the mechanical decoupling wire control brake is configured such that the brake motor (101) is indirectly controlled by the pedal opening sensor (602) through the brake control system (6), the hydraulic pressure building mechanism (4) is built up through the motor assist mechanism (1) and the mechanical decoupling mechanism (3), and the brake caliper (502) is driven to brake through the brake wheel cylinder mechanism (5). The wheel cylinder mechanism (5) drives the brake caliper (502) to brake. When the mechanical decoupling wire control brake performs mechanical backup braking in the event of a failure of the brake motor (101), the driver directly builds pressure on the hydraulic pressure building mechanism (4) through the pedal actuating mechanism (2), and then drives the brake caliper (502) to brake through the wheel cylinder mechanism (5). When the brake is returned to its original position under any working condition, the large spring (305) and the hydraulic pressure of the brake master cylinder (401) rebound to drive the retaining frame (109) and the lead screw (108) to return to their original position, and the small spring (205) drives the hollow push rod (204) and the pedal push rod (203) to return to their original position.

[0030] The control method for achieving mechanical decoupling. When the car is in unmanned automatic driving, the radar and the camera transmit the received road signals to the signal processing chip. The signal processing chip calculates the braking force and braking speed according to the vehicle information and sends a pre-braking signal to the motor control unit. The motor control unit controls the rotation of the brake motor (101), and then increases the torque of the brake motor (101) and reduces the speed through the first-stage driving gear (102), the intermediate shaft input gear (103), the intermediate shaft output gear (104), and the gear nut (105). The rotational motion of the large gear (10501) is converted into the translation of the screw (108). The translation of the screw (108) drives the retaining frame (109) to push The movable push rod joint (301), the rubber gasket (302), the master cylinder push rod seat (303), and the large spring seat (304) compress the large spring (305). At this time, the master cylinder push rod (306) starts to push the brake master cylinder (401) to build pressure, and then drives the brake caliper (502) to brake through the brake wheel cylinder mechanism (5). During the braking process, the lead screw (108) and the hollow push rod (204) have no mechanical connection in the axial direction. The translation of the lead screw (108) will not drive the translation of the hollow push rod (204). When braking, the brake pedal (201) will not follow the movement of the lead screw (108), thereby realizing mechanical decoupling of the movement between the lead screw (108) and the brake pedal (201).

[0031] In summary, the present invention has the following advantages:

[0032] 1. The hollow push rod (204) and the lead screw (108) of the braking control system have no axial mechanical connection. During wire-controlled braking, the translation of the lead screw (108) will not drive the movement of the hollow push rod (204). Therefore, the brake pedal (201) will not follow up during braking, thus achieving mechanical decoupling and being more suitable for the development of future smart cars.

[0033] 2. A ventilation channel (801) is provided between the gear chamber (707) and the lead screw chamber (708) of the mechanical decoupling wire control brake, which can reduce the resistance caused by air pressure during braking, improve efficiency, and reduce energy consumption.

[0034] 3. The original push rod joint (301) structure has many advantages. First, the push rod joint (301) has 6 end teeth (30103) and a radial boss (30104) on it, which can limit the large spring seat (304) to prevent the large spring seat (304) from separating from the push rod joint (301) during the rebound process. Secondly, the step groove (30106) of the push rod joint (301) and the lower inner ring surface (3010601) are When the mechanical standby brake rebounds, the lead screw (108) is limited, and the lower groove (3010602) allows the lead screw (108) and the push rod joint (301) to have a clearance fit (802). When the upper inner ring surface (3010603) rebounds, the hollow push rod (204) is limited, and the upper groove (3010604) allows the hollow push rod (204) and the push rod joint (301) to have a clearance fit. The rounded corners of each section make the structure more solid.

[0035] 4. The gear nut (105) is an integrated assembly of a screw nut (10502), a large gear (10501) and a bearing sleeve (107), which has simple processing technology, low cost, high strength, high production yield and long service life.

[0036] 5. The screw (108) and the push rod joint (301) of the mechanical decoupling system are clearance-matched (802), and the screw (108) drives the retaining frame (109) to transmit the power, thereby effectively reducing the impact sound of the brake during operation and meeting the need for stable and peaceful operation of the brake.

[0037] 6. The brake front housing (701) adopts an axial limit (803) for the hollow push rod (204). The front end of the brake front housing (701) is provided with a buffer gasket (702) and a polygonal cover (703). During the rebound process after the brake is applied, the hollow push rod (204) can be prevented from popping out of the front housing (701) and a certain buffer is provided.

[0038] 7. The mechanically decoupled wire-controlled brake has a low-noise structure (804) and avoids direct collision of metal parts during the entire braking and rebound process.

[0039] 8. The mechanical decoupling wire control brake has an anti-collision structure (805). During braking, the limit nut (114) on the guide column (112) blocks the guide block (110), and the master cylinder piston (404) does not collide with the master cylinder (401). BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is an overall schematic diagram of a mechanically decoupled wire-controlled brake and a braking system according to a specific embodiment of the present invention;

[0041] Figure 2 is a side view of a mechanically decoupled brake-by-wire device according to a specific embodiment of the present invention;

[0042] Figure 3 is a cross-sectional view of a mechanically decoupled brake-by-wire according to a specific embodiment of the present invention;

[0043] Figure 4 2 is a schematic structural diagram of a hollow push rod of a mechanically decoupled brake-by-wire according to a specific embodiment of the present invention;

[0044] Figure 5 2 is a schematic structural diagram of a push rod joint of a mechanically decoupled brake-by-wire according to a specific embodiment of the present invention;

[0045] Figure 6 2 is a schematic diagram of a gear nut structure of a mechanically decoupled wire-controlled brake according to a specific embodiment of the present invention;

[0046] Figure 7 2 is a schematic diagram of the front end structure of a brake front housing of a mechanically decoupled wire-controlled brake according to a specific embodiment of the present invention;

[0047] Figure 8 A schematic structural diagram of a brake screw of a mechanically decoupled wire-controlled brake according to a specific embodiment of the present invention;

[0048] The technical features represented by the accompanying figures are shown in Table 1.

[0049]

[0050]

[0051] DETAILED DESCRIPTION

[0052] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0053] The present invention mainly has the following features: the lead screw (108) and the hollow push rod (204) have no mechanical connection in the axial direction; during the braking process, the translation of the lead screw (108) will not drive the translation of the hollow push rod (204); during braking, the brake pedal (201) will not follow the movement of the lead screw (108), thereby realizing mechanical decoupling of the movement between the lead screw (108) and the brake pedal (201), meeting the needs of the development of automatic driving; an air exchange channel (801) is provided between the gear chamber (707) and the lead screw chamber (708) of the mechanical decoupling wire control brake, which facilitates exhaust, reduces air resistance during braking, and increases braking efficiency; the clearance fit (802) between the lead screw (108) and the push rod joint (301) is realized in the automatic braking process. No collision occurs during the braking process; the push rod joint (301) and the hollow push rod (204) have a unique structure; the front end of the brake front shell (701) has a buffer gasket (702) and a polygonal cover (703), which can prevent the hollow push rod (204) from popping out of the front shell (701) during the rebound process after the brake is applied; the brake has a low-noise structure (804), which avoids the noise generated by the direct collision of metal parts during the entire braking and rebound process; the brake has an anti-collision structure (805), and the limit nut (114) on the guide column (112) blocks the guide block (110), ensuring that the master cylinder piston (404) does not collide with the inner wall of the master cylinder (401).

[0054] For details, see Figure 1 、 2 , 3, 4, 5, 6, 7 and 8 show the overall schematic diagram, side view, sectional view, and assembly structure diagram of the push rod joint (301), the hollow push rod (204), the brake front housing (701), the lead screw (108), the gear nut (2042) and the bearing sleeve (107) of the braking system of the mechanical decoupling wire control brake according to the present invention.

[0055] The invention comprises a motor assist mechanism (1), a pedal actuating mechanism (2), a mechanical decoupling mechanism (3), a hydraulic pressure establishing mechanism (4), a brake wheel cylinder mechanism (5), a brake control system (6), and a brake structural component (7).

[0056] The gears in the motor assist mechanism (1) are all helical gears, and the normal pressure angle is 22.5°. The first-stage driving gear (102) rotates 23.5° to the left, is connected to the rotating shaft of the brake motor (101), and is subjected to the axial rightward force of the rotating shaft; the intermediate shaft input gear (103) rotates 23.5° to the right, meshes with the first-stage driving gear (102), and is subjected to the axial leftward force of the first-stage driving gear (102); the intermediate shaft output gear (104) rotates 27.5° to the right, is made into an integrated part with the intermediate shaft input gear (103), and is fixed to the intermediate shaft (111) through a small bearing. The material of the intermediate shaft gear is POM, which is harder and more wear-resistant; the large gear (10501) rotates 27.5° to the left, meshes with the intermediate shaft output gear (104), and is subjected to the axial leftward force of the intermediate shaft output gear (104). The material of the large gear is POM. A66 with 30% glass fiber is more resilient and has a longer bending fatigue life. When braking ends, the braking force of the brake motor (101) disappears. Under the rebound force of the large spring (305), the lead screw (108) drives all gears to rotate in the opposite direction. The direction of the axial force on all gears does not change. In order to prevent axial movement between the bearing (106) and the brake front housing (701), the bearing sleeve (107) and the bearing (106) are matched on the lead screw nut (10502). The bearing sleeve (107) is turned over and fixed to the bearing (106) by a spinning process. The bearing (106) is a deep groove ball bearing. The inner ring is interference-fitted with the optical axis part of the lead screw nut (10502) to reduce the tendency of radial relative sliding between the bearing (106) and the lead screw nut (10502). The outer ring is clearance-fitted with the brake front housing (701) to facilitate the assembly of the large bearing (106).The screw nut (10502) and the large gear (10501) are made into an integrated part gear nut (105). The material of the screw nut (10502) is selected as high-strength PA66 with self-lubricating effect plus 30% glass fiber. The screw (108) is engaged with the screw nut (10502) containing the thread, so that when the screw nut (10502) rotates, it can drive the screw (108) to move axially, and convert the rotation of the large gear (10501) into the translation of the screw (108); the material of the screw (108) is GCr15, which has the advantages of high hardness, high wear resistance and small deformation during heat treatment. One end of the retainer (109) is welded to the screw (108), and the other end is connected to the guide block (110). The guide block ( 110) cooperates with the hole axis of the guide column (112), and when the screw (108) moves axially, the guide block (110) can be moved synchronously and the screw (108) can be prevented from rotating. The material of the guide block is PA66, which is more tough and has a longer bending fatigue life. The limit nut (114) and the guide column (112) are threaded together. The smooth part of the guide column (112) has a diameter of 10 mm, and the threaded part is a coarse thread with a diameter of 8 mm. During the braking process, the limit nut (114) on the guide column (112) will block the guide block (110), thereby limiting the stroke of the retaining frame (109), the screw (108) and the master cylinder piston (404), ensuring that the master cylinder piston (404) will not collide with the inner wall of the master cylinder (401).

[0057] The brake pedal (201) is connected to the pedal push rod (203) through a lifting lug (202). The lifting lug (202) is made of Q235 and is connected to the pedal push rod (203) through a thread. The pedal push rod (203) is connected to the hollow push rod (204) through a ball joint, which is flexible and accurate in control and has a large torsion angle. The hollow push rod (204) and the lead screw (108) have no mechanical connection in the axial direction. During the braking process, the translation of the lead screw (108) will not drive the translation of the hollow push rod (204). When braking, the brake pedal (201) will not follow the lead screw (108) 8) movement, realizing mechanical decoupling of the movement between the lead screw (108) and the brake pedal (201), a gap exists between the inner wall of the hollow push rod (204) and the small spring (205) to avoid friction, the small spring (205) is a right-handed compression coil spring with the ends not tightened and not ground flat, and is made of music wire with high tensile strength, elastic limit and fatigue resistance. It is placed in the hollow push rod (204), and the front end is against the inner wall of the hollow push rod (204), and the rear end is against the master cylinder push rod seat (303), and is compressed when the driver steps on the brake pedal (201).

[0058] The push rod joint (301) in the mechanical decoupling mechanism (3) is made of PA66 plus carbon fiber. The lower inner ring surface (3010601) limits the lead screw (108) when the mechanical standby brake rebounds. The lower groove (3010602) allows the lead screw (108) and the push rod joint (301) to have a clearance fit (802). The upper inner ring surface (3010603) limits the hollow push rod (204) when it rebounds. The upper groove (3010604) allows the hollow push rod (204) and the push rod joint (301) to have a clearance fit (802). The rod joint (301) is clearance-fitted, and the bottom end face contacts the retaining frame (109). When the automatic brake is applied, the push rod joint (301) is pushed by the retaining frame (109). The material of the rubber gasket (302) is nitrile rubber. It can play a buffering role between the push rod joint (301) and the master cylinder push rod seat (303) to prevent the push rod joint (301) and the master cylinder push rod seat (303) from directly colliding. The master cylinder push rod seat (303) contacts the large spring seat (304) and is in contact with the master cylinder push rod seat (303). The rod (306) is connected by a ball joint to ensure stable transmission of force. During the braking process, the master cylinder push rod (306) is pushed. The large spring seat (304) is matched with the shaft hole of the push rod joint (301). The push rod joint (301) has 6 end teeth (30103) and a radial boss (30104) on it, which can limit the large spring seat (304) to prevent the large spring seat (304) from separating from the push rod joint (301) during the rebound process. The material of the large spring (305) is piano wire. , having high tensile strength, elastic limit and fatigue resistance, one end is pressed against the large spring seat (304), and the other end is pressed against the brake rear housing (708), and is compressed by the large spring seat (304) during braking. When braking is completed, the large spring seat (304) will rebound back to its original position. One end of the master cylinder push rod (306) is connected to the master cylinder push rod seat (303) by a ball joint to ensure stable force transmission, and the other end is pressed against the brake master cylinder (401), pushing the brake master cylinder (401) to establish hydraulic pressure during braking.

[0059] The front end of the brake master cylinder (401) in the hydraulic establishment mechanism (4) is supported by the master cylinder push rod (306), and the master cylinder push rod (306) is connected to the master cylinder piston (404). The rear end of the brake master cylinder (401) is fixedly mounted on the brake rear housing (708) by a fixing nut (705). The material of the fixing nut (705) is carbon steel. The small oil storage tank (402) is mounted on the upper end of the brake master cylinder (401). The large oil storage tank (not shown in the figure) is connected to the small oil storage tank (402) through an oil pipe. The side of the brake master cylinder (401) has two bypass holes (403), which are connected to the brake pipeline (501) and are responsible for transmitting pump fluid to stop the brake caliper (502).

[0060] The brake line (501) in the brake wheel cylinder mechanism (5) is divided into a first brake line (50101) and a second brake line (50102). One end of the brake line (501) is connected to the bypass hole (403) of the brake master cylinder (401). The other end of the first brake line (50101) is connected to the left front wheel brake caliper (50201) and the right front wheel brake caliper (50202). The other end of the second brake line (50102) is connected to the left rear wheel brake caliper (50203) and the right rear wheel brake caliper (50204). The pump fluid of the brake master cylinder (401) is transferred to the brake caliper (502) to achieve braking.

[0061] The signal processing chip, the motor control unit MCU and the brake motor (101) in the braking control system (6) are installed in the brake controller housing (601). The signal processing chip is used to process the information recognized by the vehicle-mounted sensor from the road surface and calculate the braking force and braking speed, and then send a braking signal to the motor control unit MCU. The motor control unit MCU controls the rotation of the brake motor (101). The brake motor (101) serves as the power source of the entire braking system. The pedal opening sensor (602) is installed on the brake pedal (201) to estimate the position of the pedal push rod (203). Then the pedal opening sensor (602) sends a switch signal to the signal processing chip. The signal processing chip performs pre-braking position estimation based on the pedal opening sensor (602)'s estimation of the pedal push rod (203). Four wheel speed sensors (603) are respectively installed on four brake calipers (502) to accurately, reliably and in real time detect the wheel speed of the vehicle when it is traveling.

[0062] The brake front housing (701) and the brake rear housing (708) in the brake structural member (7) are connected by bolts, and all parts are installed therein. The buffer gasket (702) has four limiting holes (70201) that form an axial hole match (80301) with the limiting columns (70102) on the brake front housing (701). The F-shaped cover (703) is assembled on the cylindrical end (70105) of the front housing (701). The F-shaped cover (703) is fixed on the cylindrical end (70105) of the front housing by changing the shape of the open end (70301) of the F-shaped cover (703). The closed boss (20402) of the hollow push rod (204) is axially limited (803) on the inner side surface of the semi-sealed end (70302) of the F-shaped cover (703), so that the hollow push rod (204) cannot be separated from the front housing screw cavity (710). The dust cover (704) is put on the brake front housing (701) and fixed with a metal tie (707); the gear cavity (709) is a cavity between the brake front housing (701) and the brake rear housing (708); and the screw cavity (710) is a cavity composed of the screw (108), the hollow push rod (204) and the push rod joint (301).

[0063] The materials of the brake motor (101), the guide column (112), the short threaded column (113), the pedal push rod (203), the hollow push rod (204), the lead screw (108), the retaining frame (109), the intermediate shaft (111), and the large spring seat (304) are all 45 steel, which has high strength and strong deformation resistance.

[0064] The specific implementation of the clearance fit (802) between the lead screw (108) and the push rod joint (301) is shown in FIG. Figure 3 The screw (108) and the retaining frame (109) are welded together, and the retaining frame (109) pushes the push rod joint (301), the rubber gasket (302), the master cylinder push rod seat (303), the large spring seat (304), and the master cylinder push rod (306), and then pushes the brake master cylinder (401) to establish hydraulic pressure. The lower groove annular surface (301060201) of the step groove (30106) of the push rod joint (301) and the screw (108) are connected. ) The outer ring surface (10802) extending out of the circular ring (10801) forms an annular surface clearance fit (80201), and the lower groove end surface (301060202) of the step groove (30106) of the push rod joint (301) and the outer end surface (10803) of the lead screw (108) extending out of the circular ring (10801) form an end surface clearance fit (80202), thereby avoiding collision between the lead screw (108) and the push rod joint (301) during braking.

[0065] The specific implementation of the hollow push rod (204) structure is shown in FIG. Figure 4The hollow push rod (204) is in the shape of a cylinder (20401) with a hollow interior and a closed boss (20402) at the front end. The closed boss (20402) has a spherical groove (20403) which can be connected to the pedal push rod (203) by a ball joint to ensure stable transmission of force. The front end surface (20404) is also evenly distributed with four circular axial air holes (20406). The front end side surface (20405) is also evenly opened with four semicircular radial air holes (20407) which cross-connect with the four circular axial air holes (20406) on the front end surface (20404), which can reduce the friction caused by air during braking. The resistance caused by pressure is reduced, efficiency is improved, and energy consumption is reduced. During automatic braking, the space of the screw cavity (710) becomes atmospheric pressure and becomes smaller. At this time, air is sucked into the dust cover (704) through the semicircular radial air vents (20407) on the front side surface (20405) of the hollow push rod (204) and the circular axial air vents (20406) on the front end surface (20404) to increase the air pressure. During mechanical backup braking, the volume of the screw cavity (710) becomes smaller and the air pressure becomes larger. The internal air is discharged to the dust cover (704) outside through the circular axial air vents (20406) on the front end surface (20404) of the hollow push rod (204) to reduce the air pressure. There is a gap between the inner wall of the hollow push rod (204) and the small spring (205), and the hollow push rod (204) and the lead screw (108) have no mechanical connection in the axial direction. During the line control braking process, the translation of the lead screw (108) will not drive the translation of the hollow push rod (204). During braking, the brake pedal (201) will not follow the movement of the lead screw (108), thereby realizing mechanical decoupling of the movement between the lead screw (108) and the brake pedal (201). In the case of mechanical backup braking, the hollow push rod (204) is separated from the lead screw (108) and moves along with the movement of the pedal push rod (203).

[0066] The specific implementation of the push rod joint (301) structure is shown in FIG. Figure 5. One end of the push rod joint (301) is a semi-closed opening (30101), and the other end is a toothed opening (30102). The bottom is a cylinder (30107). There are 6 end teeth (30103) on the cylinder (30107) and each has a radial boss (30104), which can limit the large spring seat (304). The semi-closed end of the push rod joint has a stepped groove (30106), which is composed of two inner ring surfaces and two grooves, and a groove is opened behind each inner ring surface. The lower inner ring surface (3010601) is used to limit the screw (108), and the lower groove (3010602) is opened at the back to make the screw (108) and the push rod joint (301) fit with each other (802). The lower groove (3010602) is followed by an upper inner ring surface (3010603) for the hollow push rod. The rod (204) is limited, and an upper groove (3010604) is opened on the back of the upper inner ring surface (3010603) so that the hollow push rod (204) and the push rod joint (301) are clearance-matched. The inner end surface (3010605) is opened below the upper groove (3010604). Four semicircular end surface air vents (30105) are evenly opened along the end surface at the bottom of the push rod joint (301). During automatic braking, the space of the screw cavity (710) becomes atmospheric pressure and decreases. Air is sucked into the gear cavity (709) through the semicircular end surface air vents (30105) of the push rod joint (301) to increase the air pressure. During mechanical backup braking, the volume of the screw cavity (710) decreases and the air pressure increases. The internal gas is discharged to the gear cavity (709) through the semicircular end surface air vents (30105) of the push rod joint (301) to reduce the air pressure.

[0067] The specific implementation of the gear nut (105) is shown in FIG. Figure 6 The gear nut (105) is an integrated assembly of a screw nut (10502), a large gear (10501) and a bearing sleeve (107), and has a simple processing technology, low cost, high strength and long service life.

[0068] The specific implementation of the front shell (701) is shown in FIG. Figure 7The front outer ring surface (70101) of the front shell (701) is provided with four evenly distributed fixing grooves (70102) for fixing the shaped cover (703). The front end surface (70103) of the front shell is provided with four evenly distributed limiting posts (70104) for limiting the buffer gasket (702). The buffer gasket (702) is provided with four evenly distributed limiting holes (70201) which cooperate with the hole axis of the limiting posts (70104) of the front shell to prevent direct collision between the hollow push rod (204) and the shaped cover (703). The invention plays the role of reducing impact force and reducing noise. The F-shaped cover (703) is sleeved on the cylindrical end (70105) of the front shell. The F-shaped cover (703) is fixed on the cylindrical end (70105) of the front shell by changing the shape of the open end (70301) of the F-shaped cover (703). The closed boss (20402) of the hollow push rod (204) is axially limited (803) on the inner side surface of the semi-sealed end (70302) of the F-shaped cover (703), thereby preventing the hollow push rod (204) from rebounding and popping out of the brake front shell (701) when braking is completed.

[0069] The mechanical decoupling wire-controlled brake and its braking system of the present invention perform braking in the following manner:

[0070] (1) When no one brakes, the radar and the camera send a braking signal to the signal processing chip. The signal processing chip calculates the braking force and braking speed according to the vehicle information, and then sends a braking signal to the motor control unit. The motor control unit controls the rotation of the brake motor (101), and then increases the torque of the brake motor (101) and reduces the speed through the first-stage driving gear (102), the intermediate shaft input gear (103), the intermediate shaft output gear (104), and the gear nut (105). The rotational motion of the large gear (10501) is converted into the translation of the screw (108). The translation of the screw (108) drives the retaining frame (109) and then pushes the push rod joint (301), the rubber gasket (302), the master cylinder push rod seat (303), and the large spring seat (304), so that the large spring (305) is compressed. At this time, the master cylinder push rod (306) starts to push the brake master cylinder (401) to build pressure, and then drives the brake caliper (502) through the brake wheel cylinder mechanism (5) to complete the braking.

[0071] (2) During normal braking, the driver steps on the brake pedal (201), and the pedal opening sensor (602) sends a switch signal and an opening signal to the signal processing chip. The signal processing chip sends a pre-braking signal to the motor control unit according to the pre-braking position of the pedal push rod (203). The motor control unit controls the brake motor (101) to rotate. When the pedal push rod (203) reaches the zero point of the braking position, the gap inside the system and the pre-tightening force of the large spring (305) and the brake master cylinder (401) are just eliminated. As the opening of the brake pedal (201) increases, the pedal push rod (203) continues to move after reaching the zero point of the braking position. At this time, the signal processing chip performs braking calculation according to the braking position of the pedal push rod (203) and various input signals, and sends a braking signal to the motor control unit. The motor control unit controls the brake motor (101) to continue to rotate, driving the first-stage driving gear (102) to rotate, and then the intermediate shaft input gear (103), the intermediate shaft output gear (104), and the gear nut (105) rotate. The lead screw (108) engaged with the internal thread of the lead screw nut (10502) is moved axially. Then, the retainer (109) welded to the lead screw (108) moves along the axial direction of the guide column (112). The retainer (109) pushes the push rod joint (301), the buffer gasket (302), the master cylinder push rod seat (303), and the large spring seat (305). The large spring seat (305) compresses the large spring (306). The master cylinder push rod (307) compresses the brake master cylinder (401) under the push of the master cylinder push rod seat (303). The pump oil of the brake master cylinder (401) is transported to the brake caliper (502) through the brake pipeline (501). The brake caliper (502) completes the braking of the vehicle.

[0072] (3) During mechanical backup braking, the brake cannot assist due to a failure of the brake motor (101) or other reasons. The driver steps on the brake pedal (201), and the pedal push rod (203) pushes the hollow push rod (204) to move. Due to the elastic force of the small spring (205), the push rod joint (301), the rubber gasket (302), the master cylinder push rod seat (303), and the large spring seat (304) move, overcoming the elastic force of the large spring (311) and the hydraulic pressure of the brake master cylinder (403). The master cylinder push rod (306) pressurizes the brake master cylinder (401), and the oil pumped by the brake master cylinder (401) is transported to the brake caliper (502) through the brake pipe (501). The brake caliper (502) completes the braking of the vehicle.

[0073] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be considered that the specific embodiments of the present invention are limited to these. For ordinary technicians in the technical field to which the present invention belongs, they can make several simple deductions or substitutions without departing from the concept of the present invention, which should be regarded as belonging to the scope of protection of the present invention determined by the submitted claims.

Claims

1. A mechanically decoupled wire-controlled brake and braking system, characterized in that: include: Motor assist mechanism (1), pedal actuation mechanism (2), mechanical decoupling mechanism (3), hydraulic pressure establishment mechanism (4), brake wheel cylinder mechanism (5), brake control system (6), brake structural component (7); A ventilation channel (801) is provided between the gear chamber (707) and the lead screw chamber (708) of the mechanical decoupling wire control brake; A clearance fit (802) is adopted between the lead screw (108) and the push rod joint (301); The brake front housing (701) adopts axial limiting (803) for the hollow push rod (204); The mechanically decoupled brake-by-wire system adopts a low-noise architecture (804); The mechanically decoupled brake-by-wire device adopts an anti-collision structure (805).

2. The mechanical decoupling mechanism (3) according to claim 1, characterized in that: During the braking process, the lead screw (108) and the hollow push rod (204) have no mechanical connection in the axial direction, the translation of the lead screw (108) will not drive the translation of the hollow push rod (204), and the brake pedal (201) will not follow the movement of the lead screw (108) during braking, thereby achieving mechanical decoupling of the movement between the lead screw (108) and the brake pedal (201).

3. The ventilation channel (801) according to claim 1, characterized in that: The end face vent hole (30105) on the push rod joint (301) is connected with the axial vent hole (20406) and radial vent hole (20407) on the hollow push rod (204) to form a ventilation channel (801) between the gear chamber (707) and the screw chamber (708).

4. The hollow push rod (204) according to claim 1, characterized in that: The hollow push rod (204) is a thin-walled structure with a hollow interior, a closed boss (20402) at one end, and an opening (20408) at the other end. A spherical groove (20403) is provided on the outside of the closed boss (20402). The front end surface (20404) of the hollow push rod (204) has at least one axial air vent (20406), and the front end side surface (20405) of the hollow push rod (204) has at least one radial air vent (20407).

5. The push rod joint (301) according to claim 1, characterized in that: The push rod joint (301) is a thin-walled structure with a hollow interior, a semi-closed opening (30101) at one end, and a tooth-shaped opening (30102) at the other end. There is at least one end tooth (30103) on the side of the tooth-shaped opening (30102), at least one radial boss (30104) is opened on at least one end tooth (30103), at least one end face air vent (30105) is opened on the end face of the semi-closed opening (30101), and at least one stepped groove (30106) is opened on the inner annular surface of the semi-closed opening (30101).

6. The gear nut (105) according to claim 1, characterized in that: The gear nut (105) is an integrated assembly of a screw nut (10502), a large gear (10501) and a bearing sleeve (107).

7. The clearance fit (802) according to claim 1, characterized in that: The lower groove annular surface (301060201) of the step groove (30106) of the push rod joint (301) and the outer annular surface (10802) of the screw (108) extending out of the ring (10801) form an annular surface clearance fit (80201), and the lower groove end surface (301060202) of the step groove (30106) of the push rod joint (301) and the outer end surface (10803) of the screw (108) extending out of the ring (10801) form an end surface clearance fit (80202).

8. The axial limiter (803) according to claim 1, characterized in that: The front outer ring surface (70101) of the front shell (701) has at least one fixing groove (70102), the front end surface (70103) of the front shell (701) has at least one limiting column (70104), the rubber gasket (702) has at least one limiting hole (70201), the limiting hole (70201) and the limiting column (70102) form an axial hole matching (80301), the shaped cover (70 3) Assembled on the cylindrical end (70105) of the front shell (701), the open end (70301) of the polygonal cover (703) is changed in shape to fix it on the cylindrical end (70105) of the front shell, and the closed boss (20402) of the hollow push rod (204) is axially limited (803) on the inner side surface of the semi-closed end (70302) of the polygonal cover (703), so that the hollow push rod (204) cannot be separated from the screw cavity of the front shell.

9. The low noise architecture (804) according to claim 1, characterized in that: In the mechanical decoupling wire-controlled brake, the rotational pairs formed between the primary driving gear (102) on the brake motor (101) and the intermediate shaft input gear (103), and between the lead screw nut (10502) and the lead screw (108) are all in contact between metal surfaces and non-metal surfaces; the rotational pairs formed between the intermediate shaft output gear (104) and the gear nut (105) are in contact between non-metal surfaces; the translational pairs formed between the push rod joint (301) and the rubber gasket (302), the rubber gasket (302) and the master cylinder push rod seat (303), the front end of the front shell (701) and the buffer gasket (702), and the buffer gasket (702) and the hollow push rod (204) are all in contact between metal surfaces and non-metal surfaces, thereby forming a low-noise structure (804) without relative motion between metal surfaces.

10. The anti-collision structure (805) according to claim 1, characterized in that: The mechanical decoupling wire control brake is characterized in that the guide block (110) is connected to the retaining frame (109), the retaining frame (109) is connected to the lead screw (108), the guide block (110) slides axially along the guide column (112), and the guide column (112) has a limit block (114). During the braking process, the limit block (114) on the guide column (112) limits the stroke of the guide block (110), thereby limiting the stroke of the master cylinder piston (404) through the retaining frame (109) and the lead screw (108), thereby achieving a gap between the master cylinder piston (404) and the inner wall of the master cylinder (401) during operation, so that the master cylinder piston (404) will not collide with the inner wall of the master cylinder (401).

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