Wheel brake system

Abstract

The present application provides a wheel brake system, including a caliper assembly and a wheel brake pad, the caliper assembly includes a body, a floating pin, a spring and a mounting plate; a through hole penetrating the body is provided in the body, a spring is installed in the through hole, the other end of the floating pin passes through the spring and is fixed to the mounting plate, one end of the floating pin contacts the wheel, a slot is provided at the lower part of the body, and the wheel brake pad is located in the slot; a first caliper brake pad and a second caliper brake pad are respectively installed on both sides of the slot, a caliper piston is installed in the body, a plug is installed at one end of the body away from the slot, and a working chamber is formed between the plug and the caliper piston. The present application enables the caliper assembly to perform friction brakes on the wheel brake pad from both sides through the first caliper brake pad and the second caliper brake pad through the action of the spring and the floating pin, thereby making the braking speed faster, and the wear rate of the brake pad is also slowed down compared to unilateral braking, thereby extending the life of the caliper brake pad.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicle (UAV) braking, and in particular to a wheel braking system. Background Art

[0002] A drone is a powered, unmanned aircraft. It is usually composed of a fuselage, a power unit, flight control and management equipment, a launch and recovery device, etc. It can be remotely controlled or automatically flown, and can be used once, recovered, and used multiple times. It is one of the high-tech equipment today, widely used in battlefield reconnaissance, electronic countermeasures, post-war damage assessment, ground attack and many other military operations, and is an indispensable equipment for information warfare. In the civilian field, it has been widely used in artificial rainfall, aerial remote sensing, aerial surveying and mapping, forest fire prevention, coastline patrol and other fields.

[0003] As a conventional method of taking off and landing, taxiing is adopted by many drone designers. When a drone needs to slow down and brake during taxiing or landing, the brake mechanism is used. In addition, when the wheels on both sides of the landing gear deviate or the braking force is not appropriate, it is necessary to adjust the brake mechanism to change the braking stroke, so as to adjust the braking force and prevent the brake from deviating.

[0004] When existing drones use single-pump caliper brakes, generally only one side of the caliper brake pad is in contact with the wheel brake pad, which results in slow braking speed. After a long period of friction, the overall wear rate of the brake pad is accelerated, and the frequency of brake pad replacement increases, which seriously shortens the service life of the brake pad and brake disc and increases maintenance costs. Summary of the invention

[0005] The present invention provides a wheel brake system to solve the problem that when the existing UAV adopts single-pump caliper brake, the caliper brake pad on one side rubs against the wheel brake pad, resulting in slow braking speed and rapid wear of the brake pad, which leads to increased costs.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A wheel brake system comprises a caliper assembly and a wheel brake pad, the caliper assembly comprises a body, a floating pin, a spring and a mounting plate; the mounting plate is mounted on the wheel axle of the wheel, a through hole penetrating the body is provided in the body, a spring is installed in the through hole, the other end of the floating pin passes through the spring and is fixed to the mounting plate, one end of the floating pin contacts the wheel, a groove is provided at the lower part of the body, the wheel brake pad is located in the groove; a first caliper brake pad and a second caliper brake pad are respectively installed on both sides of the groove, a caliper piston is installed in the body, a plug is installed at one end of the body away from the groove, a working chamber is formed between the plug and the caliper piston, an oil inlet is provided on the body, and the oil inlet is communicated with the working chamber.

[0008] Preferably, the inner wall of the plug is provided with an annular first groove along the circular axis of the plug, and the end of the plug close to the caliper piston is provided with a second groove; one end of the first groove is connected to the oil inlet, and the other end of the first groove is connected to the second groove. By providing the first groove and the second groove in the plug, when the caliper assembly just starts to brake, the brake fluid can flow into the first groove through the oil inlet, and then flow into the working chamber through the second groove, thereby achieving effective braking.

[0009] Preferably, a return spring is provided between the first caliper brake pad and the second caliper brake pad, an opening is provided at the top of the body, a step is provided inside the body, the return spring comprises a first clip and a second clip, the first clip and the second clip form a V-shape, one end of the return spring passes through the opening, and the bottoms of the first clip and the second clip are located on the step. When braking is completed, the first caliper brake pad loses braking force, and the spring also loses braking force to the right. The return spring resets the first caliper brake pad and the second caliper brake pad to both sides under the action of elastic force, so that the first caliper brake pad and the second caliper brake pad are separated from the wheel brake pad.

[0010] Preferably, a first sealing ring is provided between the caliper piston and the inner wall of the body, a second sealing ring is provided between the plug and the body, the first sealing ring is a star-shaped sealing ring, and the second sealing ring is an O-shaped sealing ring. The first sealing ring and the second sealing ring can prevent brake fluid leakage.

[0011] Preferably, the wheel brake system also includes a landing gear and a plunger pump, the landing gear is connected to the mounting plate through a fixed back plate, the plunger pump is installed on the landing gear, the plunger pump includes a pump housing, the interior of the pump housing is hollow, an oil circuit joint is provided on the pump housing, and the oil circuit joint is connected to the oil inlet; a motor is installed at the rear of the pump housing, a screw rod is connected to the rotating shaft of the motor, a nut is provided on the outer sleeve of the screw rod, a pump needle is fixedly connected to the nut, the pump needle sleeve is arranged outside the screw rod, and the front end of the pump needle forms a working oil chamber with the hollow pump housing. The present application drives the screw rod to rotate by the rotation of the motor, so that the nut carries the pump needle to slide along the screw rod to make the brake fluid in the working oil chamber flow out through the oil circuit joint to the caliper assembly for braking.

[0012] Preferably, the front end of the pump needle is connected with a sealing sleeve, the outer diameter of which contacts the inner wall of the pump housing, and the third and fourth sealing rings are installed outside the sealing sleeve; the end of the screw rod close to the motor is covered with a positioning ring, and the outer wall of the positioning ring contacts the inner wall of the pump housing. The sealing sleeve can prevent the brake fluid from flowing to the right, and the third and fourth sealing rings can seal the brake fluid in the working oil chamber.

[0013] Preferably, the inner wall of the pump housing is provided with a guide groove along the axial direction of the screw rod, and the outer wall of the pump needle is connected with a connecting key, and the connecting key slides in the guide groove. By providing the guide groove in the pump housing, the screw rod slides in the guide groove through the key, thereby ensuring the pump needle is guided.

[0014] Preferably, a magnet is installed on the outer wall of the pump needle near the motor side, a proximity sensor is installed on the side wall of the pump housing, and the wheel brake system also includes a controller, and the proximity sensor and the motor are connected to the controller. When braking is completed, the pump needle retreats, and when the proximity sensor senses the magnet, it means that the pump needle has retreated into place, and the motor stops rotating. The position of the proximity sensor is the starting origin of the pump needle. During the maintenance process, the origin of the pump needle can be adjusted by changing the position of the proximity sensor, which is convenient for maintenance. Of course, if the current of the motor has reached the set current and stopped rotating, and the proximity sensor does not sense the magnet, it can be determined that a mechanical failure has occurred in the system.

[0015] Preferably, a liquid storage bottle is installed at the bottom of the pump housing, an oil replenishing channel is provided at the bottom of the end of the pump housing away from the motor, and the hollow pump housing is connected to the liquid storage bottle through the oil replenishing channel; a liquid storage bottle piston is installed in the liquid storage bottle, and a fifth sealing ring is provided between the liquid storage bottle piston and the liquid storage bottle; a liquid storage bottle indicator cover is provided on the liquid storage bottle piston, and a high-pressure oil mark is provided at the end of the pump housing away from the motor; and a sealing screw plug is installed at the bottom of the liquid storage bottle. By installing the liquid storage bottle at the bottom of the pump housing, when braking, the motor rotates, and when the current of the motor reaches the set current and the brake pressure still fails to meet the set pressure, the controller controls the motor to reverse and return the pump needle to the origin. At this time, the pressure in the working oil chamber is less than the atmospheric pressure, and the liquid storage bottle piston pushes the brake fluid in the liquid storage bottle through the oil replenishing channel under the action of the atmospheric pressure to flow into the working oil chamber; in this way, when the brake fluid in the working oil chamber cannot meet the braking requirements, automatic oil replenishment is achieved. The amount of brake fluid can be observed through the reservoir bottle indicator cover and the high-pressure oil mark. When the amount on the reservoir bottle indicator cover and the high-pressure oil mark is low, you can open the sealing screw plug and add brake fluid to the reservoir bottle.

[0016] Preferably, a pressure transmitter is installed at the bottom of the pump housing, and the pressure transmitter is connected to the controller. The pressure in the working oil chamber can be monitored through the pressure transmitter.

[0017] Compared with the prior art, the invention has the following beneficial effects: the invention provides a through hole in the body, installs the spring in the through hole, one end of the floating pin contacts the wheel and the other end passes through the spring and the mounting plate and is fixed by bolts. When the drone is in a braking state, the brake fluid enters the working chamber through the oil inlet, and the high-pressure brake fluid pushes the caliper piston to cause the first caliper brake pad to rub against the wheel brake pad. Since the body is in a floating state, after the first caliper brake pad rubs against the wheel brake pad, the spring will be subjected to a rightward force. Under the action of the force, the spring will move the caliper assembly as a whole to the right so that the second caliper brake pad rubs against the wheel brake pad to brake. The invention uses the action of the spring and the floating pin to allow the caliper assembly to rub the wheel brake pad from both sides through the first caliper brake pad and the second caliper brake pad, thereby making the braking speed faster, and compared with unilateral braking, the wear rate of the brake pad is also slowed down, thereby extending the life of the caliper brake pad. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the structure of the wheel brake system provided in this application.

[0019] Figure 2 An exploded view of the wheel and caliper assembly.

[0020] Figure 3 A top view of the caliper assembly.

[0021] Figure 4 for Figure 3 Sectional view along AA.

[0022] Figure 5 for Figure 2 Left side view.

[0023] Figure 6 for Figure 5 Cross-sectional view along BB.

[0024] Figure 7 for Figure 2 Right view of .

[0025] Figure 8 for Figure 7 Sectional view along EE;

[0026] Fig. 9 for Figure 2 Schematic diagram of the combined structure.

[0027] Fig.10 This is a schematic diagram of the structure of a plunger pump.

[0028] Fig.11 for Fig.10 main view.

[0029] Fig.12 for Fig.11 Cross-sectional view along CC.

[0030] Fig.13 for Fig.10 Top view of the .

[0031] Fig.14 for Fig.13 Cross-sectional view of DD.

[0032] Markings in the figure: 1-brake device, 2-landing gear, 3-plunger pump, 4-through hole, 5-wheel, 6-wheel hub, 7-floating pin, 8-caliper assembly, 9-oil inlet, 10-spring, 11-working chamber, 12-mounting plate, 13-fixed back plate, 14-wheel axle, 15-wheel brake pad, 16-body, 17-first caliper brake pad, 18-second caliper brake pad, 19-reset spring, 20-first sealing ring, 21-caliper piston, 22-plug, 23-second sealing ring, 24-high-pressure oil mark, 25-proximity sensor, 26-electric Pneumatic connector, 27-motor, 28-oil replenishment channel, 30-oil circuit connector, 31-pump housing, 32-pump needle, 33-screw, 34-magnet, 35-positioning ring, 36-key, 37-third sealing ring, 38-fourth sealing ring, 39-sealing sleeve, 40-screw nut, 41-liquid storage bottle indicator cover, 42-working oil chamber, 43-liquid storage bottle piston, 44-liquid storage bottle, 45-sealing screw plug, 46-pressure transmitter, 48-first groove, 49-second groove, 50-first clamp, 51-second clamp, 52-step, 53-guide groove. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with test examples and specific implementation methods. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0034] like Figure 1 As shown, the wheel brake system provided by the present application includes a landing gear 2, two wheels 5 are respectively installed on both sides of the landing gear 2, a brake device 1 is installed in each wheel 5, and a fixed back plate 13 is installed on the side of the landing gear 2 to fix the landing gear 2. A plunger pump 3 is installed on the landing gear 2, and the brake device 1 in each wheel 5 is connected to the plunger pump 3 through a pipeline. A wheel hub 6 is provided in the wheel 5, and a wheel axle 14 is connected to the wheel hub 6, and a wheel brake pad 15 is installed on the wheel axle 14.

[0035] like Figures 2 to 9As shown, one end of the wheel shaft 14 passes through the wheel hub 6, and the other end of the wheel shaft 14 is fixedly connected with the wheel brake pad 15. A caliper assembly 8 is installed on the wheel brake pad 15, and the caliper assembly 8 includes a body 16, a floating pin 7, a spring 10 and a mounting plate 12; the mounting plate 12 is installed on the wheel shaft 14 of the wheel 5, and a through hole 4 is provided in the body 16 and penetrates the body 16, and a spring 10 is installed in the through hole 4, and the other end of the floating pin 7 passes through the spring 10 and is fixed to the mounting plate 12, and a gasket is provided between the mounting plate 12 and the spring 10. One end of the floating pin 7 is in contact with the wheel 5, and a groove is provided at the lower part of the main body 16, in which the wheel brake pad 15 is located; a first caliper brake pad 17 and a second caliper brake pad 18 are respectively installed on both sides of the groove, and a caliper piston 21 is installed in the main body 16, and a plug 22 is installed at one end of the main body 16 away from the groove, and a working chamber 11 is formed between the plug 22 and the caliper piston 21, and an oil inlet 9 is provided on the main body 16, and the oil inlet 9 is connected to the working chamber 11.

[0036] A first sealing ring 20 is provided between the caliper piston 21 and the inner wall of the body 16 , and a second sealing ring 23 is provided between the plug 22 and the body 16 . The first sealing ring 20 is a star-shaped sealing ring, and the second sealing ring 23 is an O-shaped sealing ring.

[0037] like Figure 4 As shown, a return spring 19 is provided between the first caliper brake pad 17 and the second caliper brake pad 18, an opening is provided at the top of the main body 16, a step 52 is provided inside the main body 16, and the return spring 19 includes a first clip 50 and a second clip 51, the first clip 50 and the second clip 51 form a V-shape, one end of the return spring 19 passes through the opening, and the bottom of the first clip 50 and the second clip 51 are located on the step 52.

[0038] like Figure 6 and Figure 8 As shown, the inner wall of the plug 22 is provided with an annular first groove 48 along the circular axis of the plug 22, and the end of the plug 22 close to the caliper piston 21 is provided with a second groove 49; one end of the first groove 48 is connected to the oil inlet 9, and the other end of the first groove 48 is connected to the second groove 49. When the brake is not applied, the front ends of the caliper piston 21 and the plug 22 are adjacent to each other. In order to allow the brake fluid to smoothly enter the working chamber 11 formed by the plug 22 and the caliper piston 21, the inner wall of the plug 22 is provided with a first groove 48 and a second groove 49. The first groove 48 is connected to the oil inlet 9, so that after the brake fluid flows in through the oil inlet 9, it enters the working chamber 11 along the first groove 48 and the second groove 49.

[0039] like Figures 10 to 14As shown, the plunger pump 3 includes a pump housing 31, the interior of the pump housing 31 is hollow, and an oil circuit joint 30 is provided on the pump housing 31, and the oil circuit joint 30 is connected to the oil inlet 9; the rear part of the pump housing 31 is installed with a motor 27, and a screw rod 33 is connected to the rotating shaft of the motor 27, and a nut is provided on the outer sleeve of the screw rod 33, and a pump needle 32 is fixedly connected to the nut, and the pump needle 32 is sleeved outside the screw rod 33, and the front end of the pump needle 32 and the hollow pump housing 31 form a working oil chamber 42. The front end of the pump needle 32 is connected with a sealing sleeve 39, and the outer diameter of the sealing sleeve 39 contacts the inner wall of the pump housing 31, and two third sealing rings 37 and two fourth sealing rings 38 are installed outside the sealing sleeve 39, and the third sealing ring 37 and the fourth sealing ring 38 are arranged at intervals, and the third sealing ring 37 is an O-type sealing ring, and the fourth sealing ring 38 is a silicone rubber sealing ring. The end of the screw rod 33 close to the motor 27 is covered with a positioning ring 35, the outer wall of the positioning ring 35 contacts the inner wall of the pump housing 31, and the axial positioning of the previous series of transmissions is achieved through the positioning ring 35. The sealing sleeve 39 uses a group of O-rings and a group of silicone rubber sealing rings to achieve sealing. The front end of the piston and the cavity of the pump body form a working oil chamber 42. When the piston is compressed, the volume of the oil chamber decreases and high-pressure brake fluid is output. Similarly, when the piston is retracted, the volume increases and the liquid flows back to the oil chamber. The oil chamber and the brake are connected by the oil circuit connected to the oil circuit connector 30.

[0040] The inner wall of the pump housing 31 is provided with a guide groove 53 along the axial direction of the screw rod 33, and the outer wall of the pump needle 32 is connected with a connecting key 36, and the connecting key 36 slides in the guide groove 53. The pump needle 32 uses the key 36 as a guide to ensure accurate linear drive.

[0041] A magnet 34 is installed on the outer wall of the pump needle 32 near the motor 27, and a proximity sensor 25 is installed on the side wall of the pump housing 31. The wheel brake system also includes a controller, and the proximity sensor 25 and the motor 27 are connected to the controller. The bar magnet 34 triggers the proximity sensor 25, and the starting point of the pump needle 32 can be set by adjusting the position of the proximity sensor 25 for positioning and mechanical jam detection.

[0042] A high-pressure oil mark 24 is provided at the front end of the plunger pump 3 to observe the remaining amount of brake fluid in the working oil chamber 42, which is sealed with a silicone high-pressure sealing pad. A liquid storage bottle 44 is installed at the bottom of the pump housing 31, and the liquid storage bottle 44 is threadedly installed with the pump housing 31, and is reliably sealed with the pump housing 31 by an O-ring. An oil replenishment channel 28 is provided at the bottom of the pump housing 31 away from the motor 27, and the hollow pump housing 31 is connected with the liquid storage bottle 44 through the oil replenishment channel 28; a liquid storage bottle piston 43 is installed in the liquid storage bottle 44, and a fifth sealing ring is provided between the liquid storage bottle piston 43 and the liquid storage bottle 44; a liquid storage bottle indicator cover 41 is provided on the liquid storage bottle piston 43, and a sealing screw plug 45 is installed at the bottom of the liquid storage bottle 44. The liquid storage bottle piston 43 is sealed with an O-ring to ensure that the brake fluid will not leak out. A pressure transmitter 46 is also installed at the bottom of the pump housing 31, and the pressure transmitter 46 is connected to the controller. An electrical connector 26 is also installed on the pump housing 31. All the wiring of the electrical components in the system is connected to the same electrical connector, which can be quickly replaced during use. When the margin is insufficient, the sealing screw plug 45 can be unscrewed to replenish the oil. The screw plug uses a silicone high-pressure sealing gasket to reliably seal. In order to ensure the closed-loop control of the system, the design uses a hydraulic transmitter to collect the pressure of the working oil chamber 42, which can be fed back to the upper computer system in real time to achieve precise control. It uses a silicone high-pressure sealing gasket to reliably seal.

[0043] Braking process: The controller controls the motor 27 to rotate forward, and the motor 27 drags the screw 33 to rotate, and drives the screw nut 40 to move forward, thereby pushing the piston of the pump composed of the pump needle 32 and the sealing sleeve 39 to move, compressing the volume of the working oil chamber 42, so that the volume of the working oil chamber 42 becomes smaller, outputs high-pressure brake fluid, and enters the brake oil circuit through the oil circuit connector 30, so that the brake device 1 generates braking force, and the pressure value in the working oil chamber 42 is fed back to the control system through the pressure transmitter 46, which can control the size of the braking force in a closed loop. The brake fluid enters the caliper pump through the oil line connector 30, flows through the first groove 48 and the second groove 49, and then enters the working chamber 11, pushing the caliper piston 21. The high-pressure brake fluid pushes the caliper piston 21 to make the first caliper brake pad 17 rub against the wheel brake pad 15. Since the body 16 is in a floating state, after the first caliper brake pad 17 rubs against the wheel brake pad 15, the spring 10 will be subjected to a rightward force. Under the action of the force, the spring 10 will move the caliper assembly 8 to the right as a whole, so that the second caliper brake pad 18 rubs against the wheel brake pad 15 to brake. When the pressure transmitter 46 detects that the pressure reaches the preset pressure value or when the current value of the motor 27 reaches the set stall current value, the motor 27 stops, the screw rod 33 is self-locked, and the braking process is completed. A relatively constant braking torque will be maintained in this state.

[0044] Braking contact process: The controller controls the motor 27 to reverse, the motor 27 drags the screw 33 to rotate, and drives the screw nut 40 to move backward, pulling the piston of the pump composed of the pump needle 32 and the sealing sleeve 39 to move backward, increasing the volume of the working oil chamber 42, and extracting brake fluid from the brake oil circuit through the oil circuit connector 30. The pressure of the brake fluid is reduced, the braking force is reduced, the first caliper brake pad 17 loses the braking force, and the spring 10 also loses the rightward braking force. The reset spring 19 resets the first caliper brake pad 17 and the second caliper brake pad 18 to both sides under the action of elastic force, so that the first caliper brake pad 17 and the second caliper brake pad 18 are separated from the wheel brake pad 15. Whether the brake state is released is determined by the pressure value feedback from the pressure transmitter 46 or the triggering of the proximity sensor 25.

[0045] The process of replenishing brake fluid from the reservoir bottle 44 to the working oil chamber 42: During the braking process, when the current value of the motor 27 reaches the set stall current value, if the pressure detected by the pressure transmitter 46 still does not reach the set pressure, the piston of the pump composed of the pump needle 32 and the sealing sleeve 39 returns to the origin. At this time, a negative pressure lower than the atmospheric pressure will appear in the working oil chamber 42, and driven by the atmospheric pressure, the atmospheric pressure pushes the reservoir bottle piston 43, and the brake fluid in the reservoir bottle 44 is pressed into the working oil chamber 42 through the oil replenishing channel 28 to replenish the brake fluid to the oil circuit.

[0046] The process of replenishing brake fluid to the reservoir bottle 44 externally: During daily maintenance, the remaining brake fluid amount in the system can be observed through the high-pressure oil mark 24 and the reservoir bottle indicator cover 41. If the fluid amount is low, the motor 27 is rotated in the reverse direction to return the piston of the pump composed of the pump needle 32 and the sealing sleeve 39 to the origin, and the sealing screw plug 45 is unscrewed. At this time, the brake fluid can be replenished from this hole.

[0047] Fault detection: During the brake release process, when it is detected that the current value of the motor 27 exceeds the set stall current value, if the proximity sensor 25 is not triggered at this time, it can be determined that a mechanical jam fault has occurred, and the controller sends a corresponding alarm signal.

[0048] The wheel brake system provided by the present application adopts a caliper floating pin 7 in conjunction with a spring 10. During the braking process, the brake caliper is in a floating state, and the caliper position is automatically adjusted by the spring 10, so that the two caliper brake pads can both contact the wheel brake pad 15 during braking. At the same time, the pressure feedback of the pressure transmitter 46 is used to achieve closed-loop control of the braking force; a proximity sensor 25 is set as the system origin to achieve fault detection; a brake fluid storage bottle 44 is designed, and automatic oil replenishment can be achieved during the operation of the equipment; multiple in-place signals have higher reliability; oil can be supplied to the two brakes at the same time to ensure the balance of the braking force of the two wheels; the remaining oil amount in the system can be directly observed through the high-pressure oil mark 24 and the storage bottle indicator cover 41.

[0049] The above is only a detailed description of the specific implementation of the present invention, rather than a limitation of the present invention. Various substitutions, modifications and improvements made by those skilled in the relevant art without departing from the principle and scope of the present invention should be included in the protection scope of the present invention.

Claims

1. A wheel brake system, characterized in that: The invention comprises a caliper assembly (8) and a wheel brake pad (15), wherein the caliper assembly (8) comprises a body (16), a floating pin (7), a spring (10) and a mounting plate (12); the mounting plate (12) is mounted on a wheel shaft (14) of a wheel (5); a through hole (4) penetrating the body (16) is provided in the body (16); a spring (10) is installed in the through hole (4); the other end of the floating pin (7) passes through the spring (10) and is fixed to the mounting plate (12) The floating pin (7) is fixed, one end of the floating pin (7) contacts the wheel (5), a groove is formed at the bottom of the body (16), and the wheel brake pad (15) is located in the groove; a first caliper brake pad (17) and a second caliper brake pad (18) are respectively installed on both sides of the groove, a caliper piston (21) is installed in the body (16), and a plug (22) is installed at one end of the body (16) away from the groove, and a space is formed between the plug (22) and the caliper piston (21). The main body (16) is provided with an oil inlet (9), and the oil inlet (9) is in communication with the working chamber (11); the wheel brake system further comprises a landing gear (2) and a plunger pump (3), the landing gear (2) is connected to the mounting plate (12) via a fixed back plate (13), the plunger pump (3) is mounted on the landing gear (2), and the plunger pump (3) comprises a pump housing (31), the interior of the pump housing (31) is hollow, and the pump housing (31) An oil circuit connector (30) is provided on the pump housing (31), and the oil circuit connector (30) is communicated with the oil inlet (9); a motor (27) is installed at the rear of the pump housing (31), a screw rod (33) is connected to the rotating shaft of the motor (27), a nut is provided on the outer sleeve of the screw rod (33), a pump needle (32) is fixedly connected to the nut, the pump needle (32) is sleeved outside the screw rod (33), and the front end of the pump needle (32) and the hollow pump housing (31) form a working oil chamber (42).

2. The wheel brake system according to claim 1, characterized in that: An inner wall of the plug (22) is provided with an annular first groove (48) along the circular axis of the plug (22), and an end of the plug (22) close to the caliper piston (21) is provided with a second groove (49); one end of the first groove (48) is communicated with the oil inlet (9), and the other end of the first groove (48) is communicated with the second groove (49).

3. The wheel brake system according to claim 1, characterized in that: A return spring (19) is provided between the first caliper brake pad (17) and the second caliper brake pad (18); an opening is provided at the top of the body (16); a step (52) is provided inside the body (16); the return spring (19) comprises a first clip (50) and a second clip (51); the first clip (50) and the second clip (51) form a V shape; one end of the return spring (19) passes through the opening; the bottoms of the first clip (50) and the second clip (51) are located on the step (52).

4. The wheel brake system according to claim 1, characterized in that: A first sealing ring (20) is provided between the caliper piston (21) and the inner wall of the body (16), and a second sealing ring (23) is provided between the plug (22) and the body (16). The first sealing ring (20) is a star-shaped sealing ring, and the second sealing ring (23) is an O-shaped sealing ring.

5. The wheel brake system according to claim 1, characterized in that: A sealing sleeve (39) is connected to the front end of the pump needle (32), the outer diameter of the sealing sleeve (39) contacts the inner wall of the pump housing (31), and a third sealing ring (37) and a fourth sealing ring (38) are installed outside the sealing sleeve (39); a positioning ring (35) is provided on the outer sleeve of one end of the screw rod (33) close to the motor (27), and the outer wall of the positioning ring (35) contacts the inner wall of the pump housing (31).

6. The wheel brake system according to claim 1, characterized in that: The inner wall of the pump housing (31) is provided with a guide groove (53) along the axial direction of the screw rod (33), and the outer wall of the pump needle (32) is connected with a connecting key (36), and the connecting key (36) slides in the guide groove (53).

7. The wheel brake system according to claim 1, characterized in that: A magnet (34) is mounted on the outer wall of the pump needle (32) on a side close to the motor (27), a proximity sensor (25) is mounted on the side wall of the pump housing (31), and the wheel brake system further comprises a controller, the proximity sensor (25) and the motor (27) being connected to the controller.

8. The wheel brake system according to claim 7, characterized in that: A liquid storage bottle (44) is installed at the bottom of the pump housing (31); an oil replenishing passage (28) is provided at the bottom of the end of the pump housing (31) away from the motor (27); the hollow pump housing (31) and the liquid storage bottle (44) are in communication through the oil replenishing passage (28); a liquid storage bottle piston (43) is installed in the liquid storage bottle (44); a fifth sealing ring is provided between the liquid storage bottle piston (43) and the liquid storage bottle (44); a liquid storage bottle indicating cover (41) is provided on the liquid storage bottle piston (43); a high-pressure oil mark (24) is provided at the end of the pump housing (31) away from the motor (27); and a sealing screw plug (45) is installed at the bottom of the liquid storage bottle (44).

9. The wheel brake system according to claim 8, characterized in that: A pressure transmitter (46) is also installed at the bottom of the pump housing (31), and the pressure transmitter (46) is connected to the controller.

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