Inverted and sealed multi-path and multi-stage pressure output pressure supplementing device for aircraft

Abstract

The invention belongs to the technical field of hydraulic systems, and discloses an aircraft multi-path multi-stage pressure output pressure supplementing device capable of being inversely sealed, which comprises an oil tank, a hand pump, an oil filler cap, an oil distribution switch and a pressure conversion valve, a protruding cylindrical cavity is formed in the upper surface of the oil tank, an oil filler cap is installed on the top of the cylindrical cavity, and an inverted flying sealing device is installed in the cylindrical cavity. A pressure oil outlet is formed in the bottom of the oil tank, a hand pump is installed on the side wall of the oil tank, and oil is pressed into the pressure oil outlet through the hand pump. An oil distribution switch is mounted on the side wall of the oil tank; an oil inlet of the oil distribution switch is communicated with the pressure oil outlet; a zero-pressure oil outlet is formed in the side wall of the oil tank, a pressure conversion valve is installed on the side wall of the oil tank, and a zero-pressure oil inlet of the pressure conversion valve is communicated with the zero-pressure oil outlet.

Description

Technical Field

[0001] The invention belongs to the technical field of hydraulic systems, and in particular relates to a multi-channel and multi-stage pressure output booster for aircraft that can be inverted and sealed. Background Art

[0002] When a helicopter is flying in the wild, if the hydraulic system runs out of oil, it is impossible to use a ground hydraulic oil truck to refill the hydraulic system with hydraulic oil. Generally, a booster is installed on the helicopter to refill the oil for self-pressurized oil tanks, accumulators and other equipment. Currently, most of the hydraulic system boosters used on helicopters are hand-cranked hydraulic pumps, which only include an open oil tank and a hand-cranked gear pump, and have the functions of storing oil and outputting pressurized oil. However, traditional boosters do not have an inverted sealing function. When the helicopter is flying at a large angle, hydraulic oil will overflow from the vent of the open oil tank. In addition, traditional boosters can only output one channel of pressurized oil, and do not have the ability to output multiple channels and multiple levels of pressurized oil. Summary of the invention

[0003] Purpose of the invention: To propose a pressure booster with multi-channel and multi-stage pressure output that can be inverted and sealed for aircraft, which integrates a hydraulic oil tank, an oil filter, a hand pump, an oil distribution switch, and a pressure conversion valve. It has the functions of storing oil, providing oil of different pressures, and diverting and reversing. Moreover, the pressure booster device can prevent oil from flowing out of the oil tank when inverted for 5 minutes, further expanding the flight scenarios of helicopters.

[0004] Technical Solution

[0005] A multi-channel and multi-stage pressure output booster for aircraft that can be inverted and sealed, comprising: a fuel tank, a hand pump, a fuel filler cap, an oil distribution switch, a pressure conversion valve, and a sampling switch;

[0006] A protruding cylindrical cavity is provided on the upper surface of the fuel tank, a fuel filler cap is installed on the top of the cylindrical cavity, and an inverted flying sealing device is installed inside the cylindrical cavity; the cylindrical cavity is provided to connect the outside air with the inside of the fuel tank and to provide an internal space for the installation of the inverted flying sealing device.

[0007] A pressure oil outlet is provided at the bottom of the oil tank, and a hand pump is installed on the side wall of the oil tank, through which the oil is pressed into the pressure oil outlet;

[0008] An oil distributor switch is installed on the side wall of the oil tank. The oil inlet of the oil distributor switch is connected to the pressure oil outlet. The pressure oil output by the hand pump flows to each system through the oil distributor switch.

[0009] A zero-pressure oil outlet is arranged on the side wall of the oil tank, and a pressure conversion valve is installed on the side wall of the oil tank. The zero-pressure oil inlet of the pressure conversion valve is connected with the zero-pressure oil outlet.

[0010] An oil sampling port is provided at the bottom of the oil tank, and a sampling switch is installed at the bottom of the oil tank, through which the oil is discharged from the oil tank;

[0011] Furthermore, the oil tank is a rectangular shell or a cylindrical shell; a fixed support is provided on the bottom edge.

[0012] Further, the inverted flying sealing device comprises: a compression spring, a compression sleeve, a conical cover, a sealing steel ball, and a valve assembly;

[0013] A blind hole is provided below the mouth cover, the pressing sleeve is a cylinder, a connecting platform is provided in the middle of the cylinder, and an upper hollow cylinder and a lower hollow cylinder which are interconnected are provided at the upper and lower end surfaces of the center of the connecting platform respectively;

[0014] The outer wall of the pressing sleeve body matches the inner wall of the cover and has a certain gap; the upper hollow cylinder is inserted into the blind hole below the cover; the compression spring is set outside the upper hollow cylinder and between the cover and the pressing sleeve connecting platform; the gap between the outer wall of the pressing sleeve body and the cover allows the outside air to enter the fuel tank cover through the gap; the compression spring is set to fix the fuel tank cover;

[0015] The conical cover is connected to the outer side of the lower hollow cylinder, a steel ball is arranged at the inner bottom of the conical cover, and a valve assembly is arranged above the steel ball. The conical cover is arranged to fix the position of the sealing steel ball;

[0016] The lower hollow cylinder is provided with a first vent hole along the radial direction. Under normal circumstances, the first vent hole is higher than the valve assembly. The upper hollow cylinder is provided with a second vent hole along the radial direction. The air inside the oil tank enters the inside of the oil tank cover through the first vent hole and the second vent hole.

[0017] Further, the hand pump includes a handle connecting rod and an actuator;

[0018] The actuator is installed in the oil tank and the oil outlet of the actuator is directly opposite to the pressure oil outlet; the handle connecting rod is arranged on the top of the oil tank and the handle connecting rod is connected to the piston rod. The arrangement of the actuator in the oil tank can absorb oil from the oil tank and output the oil after pressurization.

[0019] Furthermore, the oil distribution switch comprises: a housing, a spherical valve, and a handle;

[0020] The housing is provided with an oil inlet and four oil outlets, and a valve cavity is provided inside; the oil inlet is located on one side of the valve cavity;

[0021] A spherical valve is arranged in the valve cavity, an oil passage is arranged inside the spherical valve, an inlet of the oil passage is parallel to the axis of the spherical valve and connected to the oil inlet, and an outlet of the oil passage is perpendicular to the axis of the spherical valve;

[0022] The four oil outlets are arranged at 90 degrees to each other, and the oil channel outlet and the four oil outlets are located in the same plane; by rotating the spherical valve, the oil channel outlet can be connected to a single oil outlet;

[0023] The end of the ball valve without oil passage extends out of the housing and is connected to a handle. By rotating the handle, the direction of the oil passage outlet in the ball valve can be controlled;

[0024] Furthermore, the inner diameters of the four oil outlets are different, thereby forming different oil outlet pressures. The inner diameter of the oil outlet with a large oil outlet pressure needs to be reduced accordingly, so that when the system is pressurized by the hand pump, the operating force acting on the hand pump will be reduced.

[0025] Furthermore, the oil distribution switch also includes: a limit spring and a limit steel ball;

[0026] One end of the limit spring is connected to the inner wall of the valve cavity, and the other end is connected to the limit steel ball;

[0027] The side wall of the spherical valve is provided with four notches along the circumferential direction, and the limiting steel balls are pressed into the notches by the limiting springs to limit the spherical valve in the circumferential direction.

[0028] Furthermore, the pressure conversion valve comprises: a pressure conversion valve housing, a valve core, a valve sleeve, a coil spring, and a spring seat;

[0029] The housing of the pressure conversion valve is a cylinder with an opening at one end; a zero-pressure oil inlet and an oil outlet are arranged on the side wall of the cylinder, and the oil outlet is close to the opening end;

[0030] A spring seat is provided at the bottom of the inner side of the pressure conversion valve housing, and a coil spring is sleeved on the spring seat; a valve sleeve is arranged in the pressure conversion valve housing to provide space for the valve core to move;

[0031] The valve core is arranged in the valve sleeve and is located above the coil spring;

[0032] The side wall of the valve sleeve is provided with a valve sleeve oil inlet and a valve sleeve oil outlet; the valve sleeve oil inlet is aligned with the zero pressure oil inlet, and the valve sleeve oil outlet is aligned with the oil outlet, so as to ensure that the oil can enter from the zero pressure oil inlet and flow out from the oil outlet;

[0033] When the coil spring is in the natural state, the valve core is located at the side of the valve sleeve oil outlet close to the opening end of the pressure conversion valve housing. In this position, the valve core can prevent the oil from flowing in from the zero pressure oil inlet and then flowing out from the pressure oil inlet.

[0034] Furthermore, it also includes a sampling switch, which is installed at the bottom of the oil tank; the sampling switch includes: a sampling switch housing, a sampling valve assembly, a sampling handle and a small spring;

[0035] The sampling switch housing is a cylinder as a whole, with a sampling oil inlet at one axial end and a sampling oil outlet at one radial end;

[0036] A valve cavity is provided inside, a sampling valve assembly is arranged in the valve cavity, one end of the small spring is connected to the sampling valve assembly, and the other end is connected to the side wall of the valve cavity;

[0037] The sampling handle passes through the sampling switch housing and is connected to the sampling valve assembly;

[0038] In the natural state, the small spring compresses the sampling valve assembly to close the valve cavity to prevent oil leakage.

[0039] In summary, the beneficial effects of the present invention are as follows:

[0040] The pressure-replenishing device with multi-channel and multi-level pressure output and inverted sealing function involved in the present invention provides a new type of pressure-replenishing device for helicopter hydraulic systems. When the helicopter is in a field environment and needs to replenish the pressure of the hydraulic system, the device can be used to replenish the pressure of multiple hydraulic systems with different pressure levels. Compared with the traditional hand-cranked pump oil tank assembly, the application scenarios of the hand-cranked pump oil tank assembly are increased and the use efficiency is improved. At the same time, the pressure-replenishing device has an inverted sealing function, which can ensure that the oil does not leak when the oil tank is inverted, and can be used in more flight scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is the general arrangement diagram of the booster;

[0042] 1-Fuel filler cap, 2-pressure oil filter, 3-observation window, 4-RJ oil port, 5-SJ oil port, 6-sampling switch, 7-oil distribution switch, 8-pressure conversion valve, 9-oil tank housing, 10-hand pump.

[0043] Figure 2 This is the principle diagram of the booster;

[0044] 2-pressure oil filter, 4-RJ oil port, 5-SJ oil port, 6-sampling switch, 7-oil distribution switch, 8-pressure conversion valve, 9-oil tank housing, 10-hand pump.

[0045] Figure 3 Detail of the fuel filler cap;

[0046] 1-1 cover, 1-2 compression spring, 1-3 second vent hole, 1-4 first vent hole, 1-5 valve assembly, 1-6 sealing steel ball, 1-7 conical cover, 1-8 sealing gasket, 1-9 compression sleeve.

[0047] Figure 4 This is a detailed drawing of the hand pump;

[0048] 10-1 handle connecting rod, 10-2 piston rod, 10-3 piston, 10-4 metal sealing gasket, 10-5 steel ball, 10-6 spring.

[0049] Figure 5 This is the detailed diagram of the oil distribution switch;

[0050] 7-1 limit steel ball, 7-2 limit spring, 7-3 handle, 7-4 spherical valve, 7-5 sealing ring, 7-6 butterfly spring.

[0051] Figure 6 This is a detailed diagram of the pressure conversion valve;

[0052] 8-1 screw, 8-2 valve sleeve, 8-3 valve core, 8-4 oil outlet, 8-5 coil spring, 8-6 spring seat, 8-7 pressure conversion valve housing, 8-8 zero pressure oil inlet, 8-9 pressure oil inlet.

[0053] Figure 7 It is a schematic diagram of the sampling switch structure;

[0054] 6-1 sampling oil inlet, 6-2 small spring, 6-3 sealing gasket, 6-4 oil outlet, 6-5 sampling handle, 6-6 sampling valve assembly, 6-7 sampling switch housing. DETAILED DESCRIPTION

[0055] A multi-channel and multi-stage pressure output booster for aircraft that can be inverted and sealed, comprising: a hydraulic oil tank, an oil filter, a hand pump, a fuel filler cap, an oil distribution switch, a pressure conversion valve, and a sampling switch;

[0056] The upper surface of the fuel tank is provided with a protruding cylindrical cavity, and the top of the cylindrical cavity is provided with a fuel filler cap 1. The structure is shown in FIG. Figure 3 As shown, it is mainly composed of a cover, a compression spring, a compression sleeve, a sealing gasket, a valve assembly, a sealing steel ball, a conical cover, and a vent. The cover 1-1 is connected to the compression spring 1-2, and the other end of the spring is fixed on the compression sleeve 1-8. An inverted sealing device is set below the compression sleeve, the inner wall of the conical cover 1-6 cooperates with the outer wall of the compression sleeve, the sealing steel ball 1-5 is located above the conical cover with a small hole, and the valve assembly 1-4 and the sealing gasket 1-7 are above the sealing steel ball. When the oil filling operation is completed and the oil filling port cap needs to be tightened, the cover compresses the compression spring, rotates the cover so that the cover falls into the slot, and the compression spring extends to fix the cover above the cylindrical cavity. The valve assembly can open or interrupt the connection between the outside atmosphere and the inside of the oil tank by moving up and down in the conical cover. Under normal working conditions, the air in the oil tank is connected to the atmosphere; when the oil tank is inverted, the valve assembly in the device is closed by the oil pressure to prevent oil leakage in the oil tank.

[0057] A pressure oil outlet is provided at the bottom of the oil tank, and a hand pump 10 is installed on the side wall of the oil tank. Figure 4As shown, the hand pump is mainly composed of a handle connecting rod, a piston rod, a piston, a metal sealing gasket, a steel ball, and a spring. Two piston actuators are located inside the oil tank. The hand pump handle connecting rod 10-1 is connected to the piston rods of the two piston actuators, and the end of the piston rod is fixed to the piston 10-3. A pressure oil channel is set below the piston actuator, and a flow channel steel ball 10-5 and a flow channel spring 10-6 are set at the lower end of the oil channel. In the case of no pressure oil output, the flow channel spring presses the flow channel steel ball against the pressure oil channel, blocking the connection between the oil in the piston and the pressure oil outlet. When outputting pressure oil, the oil is transported from the piston to the pressure oil outlet by shaking the hand pump up and down, and the oil in the oil tank is replenished into the piston. The setting of two piston actuators inside the oil tank allows the hand pump to output pressure oil twice in one cycle of shaking up and down, increasing the oil output flow.

[0058] The oil distribution switch 7 is installed on the side wall of the oil tank. Figure 5 As shown, the oil distribution switch includes: a limit steel ball, a limit spring, a spherical valve, a handle, a sealing ring, and a butterfly spring. A spherical valve 7-4 is set in the center of the oil distribution switch. The end of the spherical valve without an oil path extends out of the switch housing and is connected to the handle 7-3. The spherical valve can be controlled to rotate accordingly by turning the handle. An oil path is set at the other end of the spherical valve. The oil path inlet is located at the end face of the column, and the oil path outlet is located at the spherical side wall. There is only one channel for the oil path outlet, and the switch housing is provided with 4 oil outlets. The oils between the 4 oil outlets are not connected to each other, so as to ensure that there is no oil leakage between the oil outlets. There are 4 grooves on the rotating shaft of the spherical valve for limiting. When the handle is turned to the corresponding position, the limit steel ball 7-1 is sunk into the limit groove on the rotating shaft under the elastic force of the limit spring 7-2. When the oil is supplemented to different hydraulic systems through the booster, the handle is turned to adjust the position of the spherical valve so that the oil path outlet in the spherical valve is only connected to one oil outlet on the switch housing at a time.

[0059] The pressure conversion valve 8 is installed on the side wall of the oil tank. Figure 6 As shown, the pressure conversion valve includes a valve sleeve, a pressure conversion valve housing, a spring seat, a coil spring, a valve core, and a screw; the zero-pressure oil inlet 8-8 of the pressure conversion valve is directly connected to the oil tank through an opening in the inner wall of the oil tank; one end of the pressure oil inlet is fixed to the oil distribution switch interface through a screw 8-1, and is connected to an oil outlet of the oil distribution switch. The pressure conversion valve housing 8-7 is a cylindrical cavity, the valve sleeve 8-2 is fixed in the housing, and a spring seat 8-6 is set between the valve sleeve and the housing to support the coil spring 8-5, and the other end of the coil spring is connected to the valve core 8-3. The zero-pressure oil inlet and the oil outlet are kept in communication, so that the oil in the oil tank can flow directly to the oil outlet; when the pressure oil inlet has pressure oil input, the pressure acts on the valve core, so that the coil spring is compressed, and the valve core moves to the left, blocking the communication between the zero-pressure oil inlet and the oil outlet, and the pressure oil inlet is connected to the oil outlet, and the pressure oil is discharged from the oil outlet.

[0060] The sampling switch 6 is installed at the bottom of the oil tank. Figure 7 As shown, the sampling switch includes a small spring, a sealing gasket, a sampling handle, a sampling valve assembly, and a sampling switch housing; the bottom opening of the oil tank housing is connected to the sampling oil inlet 6-1 of the sampling switch, and there is a cylindrical cavity in the sampling switch housing 6-7, and there is a sampling valve assembly 6-6 in the cavity, one end of the sampling valve assembly is connected to the small spring 6-2, and the other end extends out of the sampling switch housing and is connected to the sampling handle 6-5. When oil sampling is required, the sampling handle is pressed to drive the valve assembly to compress the small spring, and the oil flows out from the oil outlet 6-4 through the gap between the sampling valve assembly and the sealing gasket 6-3.

[0061] The SJ oil port is set at the bottom of the oil tank side wall, and the external hydraulic system can draw oil from this port;

[0062] The RJ oil port is set in the middle of the side wall of the oil tank and arranged on the same side as the SJ oil port. The hydraulic oil sucked from the SJ oil port by the external hydraulic system can flow back to the oil tank from the RJ port;

[0063] The working principle of booster is as follows Figure 2 As shown. The booster has its own oil tank, and a visual observation window is set on the oil tank shell 9 for observing the remaining oil in the tank. If the oil is insufficient, the oil needs to be replenished to the top of the observation window in time. A refueling cap 1 is set at the top of the oil tank, and a vent is set in the cap. The air inside the oil tank communicates with the atmosphere through the vent, the gap between the cap and the pressure sleeve to prevent vacuum in the oil tank; at the same time, a reverse flight sealing device is set in the refueling cap to ensure that the helicopter does not leak oil when conducting large-angle test flight subjects; the pressure oil filter 2 can filter the oil in the oil circuit; the sampling switch 6 can realize oil sampling; the hand pump 10 can pressurize the oil in the oil tank and then output it; the oil separation switch 7 can realize the pressure oil circuit to communicate with different systems respectively; the pressure conversion valve 8 can control the conversion of the oil circuit when the output oil reaches a certain pressure.

[0064] Use scenario of pressure conversion valve: the oil in the oil tank is fixedly output to a hydraulic system through the pressure conversion valve. At this time, the booster oil tank is connected to the atmosphere, and the output oil is 0MPa. When the hydraulic system has parts and accessories to be disassembled, the hydraulic system needs to be vented. At this time, rotate the oil distribution switch handle 7-3 to connect the oil distribution switch oil outlet with the pressure conversion valve pressure oil inlet 8-9, shake the hand pump handle connecting rod 10-1 up and down, and the oil is output to the pressure conversion valve pressure oil inlet under the pressure of the hand pump. When the pressure reaches 1MPa, the oil overcomes the resistance of the spring 8-5, pushes the valve core 8-3 to move, blocks the connection between the zero pressure inlet 8-8 and the oil outlet 8-4, and connects the pressure oil inlet 8-9 with the oil outlet 8-4, thereby completing the output of oil at different pressures.

[0065] Multi-channel and multi-level pressure oil output scenario: The oil distribution switch 7 has four oil outlets. When there are multiple hydraulic systems with different pressure levels on the machine that need to be supplemented with hydraulic oil, by rotating the oil distribution switch handle 7-3, the pressure replenishment operation can be completed for different hydraulic systems respectively, and the outer diameters of the four oil outlets are different, which can be determined according to the pressure of the external system. The outer diameter of the oil outlet of the system with higher pressure needs to be reduced accordingly. This setting can ensure that when high-pressure oil is output, the operating force fed back to the hand pump handle is equivalent to that when low-pressure oil is output.

[0066] Inverted usage scenario: Under normal working conditions, the air in the fuel tank 9 is connected to the outside atmosphere. When the fuel tank is inverted, the steel ball 1-5 in the fuel filler cap 1 falls under the influence of gravity and hits the valve assembly 1-4, causing the valve assembly to press the sealing gasket, thereby blocking the vent 1-3 from being connected to the outside to prevent oil leakage. When the fuel tank returns to normal, the valve assembly and the steel ball fall under the influence of gravity, and the vent is restored to be connected to the outside atmosphere.

Claims

1. An invertible and sealable multi-channel and multi-stage pressure output booster for aircraft, characterized in that: include: Fuel tank, hand pump, fuel filler cap, oil distributor switch, pressure conversion valve, sampling switch; A protruding cylindrical cavity is provided on the upper surface of the fuel tank, a fuel filler cap is installed on the top of the cylindrical cavity, and an inverted flying sealing device is installed inside the cylindrical cavity; A pressure oil outlet is provided at the bottom of the oil tank, and a hand pump is installed on the side wall of the oil tank, through which the oil is pressed into the pressure oil outlet; An oil distributor switch is installed on the side wall of the oil tank, and the oil inlet of the oil distributor switch is connected with the pressure oil outlet; A zero-pressure oil outlet is arranged on the side wall of the oil tank, and a pressure conversion valve is installed on the side wall of the oil tank. The zero-pressure oil inlet of the pressure conversion valve is connected with the zero-pressure oil outlet.

2. The booster according to claim 1, characterized in that: The oil tank is a rectangular shell or a cylindrical shell; a fixed support is provided on the bottom edge.

3. The booster according to claim 2, characterized in that: The fuel filler cap includes: a compression spring, a compression sleeve, a conical cover, a sealing steel ball, and a valve assembly; A blind hole is provided below the mouth cover, the pressing sleeve is a cylinder, a connecting platform is provided in the middle of the cylinder, and an upper hollow cylinder and a lower hollow cylinder which are interconnected are provided at the upper and lower end surfaces of the center of the connecting platform respectively; The outer wall of the pressing sleeve body is matched with the inner wall of the mouth cover; the upper hollow cylinder is inserted into the blind hole below the mouth cover; the compression spring sleeve is arranged outside the upper hollow cylinder and between the mouth cover and the pressing sleeve connection platform; The conical cover is connected to the outer side of the lower hollow cylinder, a sealing steel ball is arranged at the inner bottom of the conical cover, and a valve assembly is arranged above the sealing steel ball; The lower hollow cylinder is provided with a first vent hole along the radial direction. Under normal circumstances, the first vent hole is higher than the valve assembly; the upper hollow cylinder is provided with a second vent hole along the radial direction.

4. The booster according to claim 3, characterized in that: The hand pump includes a handle connecting rod and an actuator; The actuator is installed in the oil tank and the oil outlet of the actuator is directly opposite to the pressure oil outlet; the handle connecting rod is arranged on the top of the oil tank and the lower end of the handle connecting rod is connected to the piston rod of the actuator.

5. The booster according to claim 4, characterized in that: The oil distribution switch includes: a switch housing, a spherical valve, and a handle; The switch housing is provided with an oil inlet and four oil outlets, and a valve cavity is provided inside; the oil inlet is located on one side of the valve cavity; A spherical valve is arranged in the valve cavity, an oil passage is arranged inside the spherical valve, an inlet of the oil passage is parallel to the axis of the spherical valve and connected to the oil inlet, and an outlet of the oil passage is perpendicular to the axis of the spherical valve; The four oil outlets are arranged at 90 degrees to each other, and the oil channel outlet and the four oil outlets are located in the same plane; One end of the spherical valve without an oil passage extends out of the housing and is connected to a handle.

6. The booster according to claim 5, characterized in that: The inner diameters of the four oil outlets are different, resulting in different oil outlet pressures.

7. The booster according to claim 5, characterized in that: The oil distribution switch also includes: a limit spring and a limit steel ball; One end of the limit spring is connected to the inner wall of the valve cavity, and the other end is connected to the limit steel ball; A notch is arranged on the side wall of the spherical valve, and a limiting steel ball is pressed into the notch by a limiting spring to limit the spherical valve in a circumferential direction.

8. The booster according to claim 7, characterized in that: The pressure conversion valve includes: a pressure conversion valve housing, a valve core, a valve sleeve, a coil spring, and a spring seat; The housing of the pressure conversion valve is a cylinder with an opening at one end; a zero-pressure oil inlet and an oil outlet are arranged on the side wall of the cylinder, and the oil outlet is close to the opening end; A spring seat is provided at the bottom of the inner side of the pressure conversion valve housing, and a coil spring is sleeved on the spring seat; the valve sleeve is arranged in the pressure conversion valve housing; The valve core is arranged in the valve sleeve and is located above the coil spring; The side wall of the valve sleeve is provided with a valve sleeve oil inlet and a valve sleeve oil outlet; the valve sleeve oil inlet is aligned with the zero pressure oil inlet, and the valve sleeve oil outlet is aligned with the oil outlet; When the coil spring is in a natural state, the valve core is located at a side of the valve sleeve oil outlet close to the opening end of the pressure conversion valve housing.

9. The booster according to claim 8, characterized in that: It also includes a sampling switch, which is installed at the bottom of the oil tank; the sampling switch includes: a sampling switch housing, a sampling valve assembly, a sampling handle and a small spring; The sampling switch housing is a cylinder as a whole, with a sampling oil inlet at one axial end and a sampling oil outlet at one radial end; A valve cavity is provided inside, a valve assembly is arranged in the valve cavity, one end of the small spring is connected to the valve assembly, and the other end is connected to the side wall of the valve cavity; The sampling handle passes through the sampling switch housing and is connected to the valve assembly; In the natural state, the small spring presses the valve assembly to close the valve cavity.

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