A helicopter rotor brake hydraulic system

Abstract

The present application relates to a kind of helicopter rotor brake hydraulic systems, the hydraulic system is by hydraulic power source subsystem, control unit, pollution isolation unit, redundancy module, load;The hydraulic power source subsystem outputs high-pressure hydraulic energy source, passes through control unit control pressure state, delivery to the entrance of pollution isolation unit, pollution isolation unit passes on pressure to redundancy module, the redundancy module responds to the control instruction issued by cockpit and realizes the on-off of pressure transmission oil circuit to load.This application has double insurance design on the rotor brake supply pressure oil circuit, avoids in the air hydraulic pressure into rotor brake device causes non-instructive rotor brake;System is designed with buffer device, avoids hydraulic pressure impact when rotor brake;Set pollution isolation device, carry out pollution key isolation to rotor brake device, improve the pollution control ability of hydraulic system.When helicopter is parked for a long time, the rotor brake pressure of helicopter can be kept by manual mode.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic system design, in particular to a helicopter rotor brake control hydraulic system. BACKGROUND

[0002] The helicopter rotor brake system can not only realize the quick stop of the rotor, but also can assist the helicopter to resist the side wind during parking. In addition, the rotor brake is also needed during the strong wind starting process of the engine.

[0003] In the prior art, the hydraulic pressure is mostly used as the power source for the rotor brake of the heavy-tonnage helicopter. However, the existing helicopter rotor brake hydraulic system has the following three shortcomings: no safety design is provided on the pressure supply oil path, which reduces the safety of the rotor brake hydraulic system; the system adopts the form of direct series connection of the hydraulic source-rotor brake pressure regulating valve-rotor brake device, which generates a large impact on the rotor brake device and other accessories during the pressure supply of the brake system, affects the service life of the system accessories, and the impact and wear will increase the generation of system pollutants; since there are a large number of rotor brake actuating cylinders in the rotor brake device, the piston rods are directly exposed to the external environment, and with the frequent reciprocating motion of the piston rods, a large amount of solid pollutants from the outside will be brought into the actuating cylinder and enter the hydraulic system. Under the action of high temperature and high pressure during the brake process, the oil in the actuating cylinder will accelerate carbonization and easily produce oxides and oil dirt and other pollutants. However, the existing helicopter rotor brake hydraulic system does not have pollution isolation measures for the key pollution sources such as the brake device, which causes the frequent pollution of the main system oil to exceed the standard, increases the maintenance workload, and also causes the waste of hydraulic oil. In view of the above-mentioned shortcomings of the existing helicopter rotor brake hydraulic system, a technology is needed to meet the requirements of high safety, high stability and pollution oil isolation of the rotor brake hydraulic system. SUMMARY

[0004] The purpose of the present application is to provide a helicopter rotor brake hydraulic system. The helicopter rotor brake hydraulic system has a double safety design on the rotor brake pressure supply oil path, which avoids the non-instruction rotor brake caused by the hydraulic pressure entering the rotor brake device in the air. The system is designed with a buffer device to avoid the impact of hydraulic pressure during the rotor brake. A pollution isolation device is provided to isolate the key pollution of the rotor brake device and improve the pollution control ability of the hydraulic system. When the helicopter is parked for a long time, the rotor brake pressure of the helicopter can be maintained by manual mode.

[0005] Technical solution: The helicopter rotor brake hydraulic system, the hydraulic system is by hydraulic power source subsystem, control unit, pollution isolation unit, redundancy module, load; the hydraulic power source subsystem outputs high pressure hydraulic energy, through control unit control pressure state, delivery to the pollution isolation unit entrance, pollution isolation unit will pressure transmission to redundancy module, the redundancy module responds to the control instruction issued by the cockpit realizes the on-off of pressure transmission oil circuit to load.

[0006] Further, the hydraulic power source subsystem includes an oil tank, a return oil filter, a bypass valve, a return check valve, a brake accumulator, an accumulator pressure signaler, an accumulator pressure gauge, a brake pressure oil filter, a first check valve, a hand pump, a second check valve, and an electric pump; the electric pump sucks oil from the oil tank, and the oil passes through the second check valve and is filtered by the brake pressure oil filter, and then is divided into one way entering the brake accumulator for energy storage and the other way entering the rotor brake pressure control unit; when the brake pressure is released, the return oil flows back to the oil tank through the return check valve and the return oil filter; when the electric pump cannot be started during long-term parking on the ground, the hand pump can also be used to suck oil from the oil tank to supplement the pressure of the brake accumulator; the first check valve and the second check valve can prevent the oil from entering the hand pump or the electric pump in reverse, thereby avoiding damage to the pump body; when the flow resistance of the return oil filter increases by a certain value, the bypass valve is connected to prevent the return oil from being unable to flow back.

[0007] Further, the return oil filter is used in combination with the bypass valve; when the flow resistance of the return oil filter exceeds the design flow resistance of the bypass valve, the return oil can flow through the bypass valve, thereby avoiding the rotor brake device from being pressurized due to poor return oil.

[0008] Further, the accumulator pressure signaler is in communication with the air cavity of the brake accumulator; when the pressure of the brake accumulator is lower than the set value, the electric pump is automatically started to charge the accumulator to the set pressure; the set charging pressure of the accumulator is higher than the rotor static brake pressure value Pstatic.

[0009] Further, the control unit includes a brake pressure regulating valve, a pressure valve operating steel cable, and a brake pressure regulating valve operating handle; the pilot adjusts the brake pressure regulating valve operating handle to different positions in the cockpit, controls the valve core action and opening area of the brake pressure regulating valve through the pressure valve operating steel cable, so as to realize different brake pressure value outputs of the dynamic brake and the static brake.

[0010] Further, the brake pressure regulating valve has the functions of reversing and pressure regulating; when the brake pressure regulating valve control rod is in the b position corresponding to the dynamic brake position, the brake pressure regulating valve supply pressure port P and the load port A are connected, and the pressure is reduced to the dynamic brake pressure Pdynamic at the same time; when the brake pressure regulating valve control rod is in the a position corresponding to the static brake position, the brake pressure regulating valve supply pressure port P and the load port A are connected, and the pressure is reduced to the static brake pressure Pstatic at the same time; and Pdynamic < Pstatic.

[0011] Further, the pollution isolation unit is achieved by using an oil isolation device; the oil isolation device is arranged between the oil inlet and the oil outlet, so that the rotor brake device is not connected with the oil tank.

[0012] Further, the pressure transmission between the a cavity and the b cavity in the oil isolation device functions as a hydraulic spring, which can effectively reduce the pressure impact when the brake pressure regulating valve is opened, and protect the accessories and reduce the impact and wear.

[0013] Further, the oil isolation device has the function of isolating the main system oil tank from the key pollution source. The oil isolation device divides the brake hydraulic system oil into two parts, one part is between the brake small oil tank and the rotor brake actuating cylinder, and the other part is between the oil isolation device and the oil tank; the oil between the two parts is isolated by the dynamic sealing ring of the piston in the oil isolation device.

[0014] Further, the redundancy module includes a rotor brake safety valve, a brake safety valve micro switch, a safety valve control cable, a brake safety valve control handle, and a brake small oil tank. The pilot controls the safety valve control cable in the cockpit and moves to different positions, and the rotor brake safety valve works in the safety position or the disconnected position; when the rotor brake safety valve works in the safety position, the rotor brake device is connected with the brake small oil tank; when the rotor brake safety valve works in the disconnected position, the pressure between the rotor brake device and the oil isolation device is connected and transmitted, and at this time, the brake safety valve micro switch is triggered.

[0015] Further, the rotor brake actuating cylinder is connected through a hydraulic hose at the pressure supply port, and one end of the hydraulic hose is connected with a guide pipe through a quick-release self-sealing joint, so that the oil circuit between the rotor brake device and the hydraulic source can be disconnected, and the system can be vented or the rotor brake device can be maintained.

[0016] Further, the rotor brake safety valve is a two-position two-way on-off valve.

[0017] Further, the brake small oil tank is an open oil tank, which is connected with the atmosphere, and the rotor brake device disconnected pipeline bubble will automatically move to the upper part of the brake small oil tank, which is conducive to the system venting.

[0018] Further, the brake accumulator charging pressure value P is close to the rotor static brake pressure value Pstatic, but the maximum working pressure of the accumulator should be greater than the rotor static brake pressure value Pstatic.

[0019] Further, the brake small oil tank is provided with an oil level observation window, an oil level scale line and a mark, which are used for observing the oil level when the rotor is parked for a long time.

[0020] Beneficial technical effects: the present application relates to a kind of helicopter rotor brake hydraulic systems, with double insurance design on rotor brake supply pressure oil line, avoid in the air hydraulic pressure into rotor brake device causes non-instructive rotor brake;System is designed with buffer device, avoid hydraulic pressure impact when rotor brake;Set up pollution isolation device, carry out pollution key isolation to rotor brake device, improve the pollution control ability of hydraulic system.When helicopter is parked for a long time, the static brake pressure of helicopter rotor can be maintained by manual mode. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 For the system component diagram of the present application. DETAILED DESCRIPTION

[0022] The technical solutions of the present application will be described clearly and completely in combination with the drawings.Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments.Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the present application.

[0023] Referring to the drawings Figure 1 , a kind of helicopter rotor brake hydraulic system is specifically designed in the present application, the helicopter rotor brake hydraulic system includes oil tank 1, back oil filter 2, bypass valve 3, back oil check valve 4, brake pressure regulating valve 5, oil isolation device 6, brake pressure signaler 7, quick-release self-sealing joint 8, hydraulic hose 9, rotor brake actuator 10, rotor brake safety valve 11, brake pressure safety valve 25, brake safety valve micro switch 12, safety valve operating cable 13, brake safety valve operating handle 14, brake small oil tank 15, pressure valve operating cable 16, brake pressure regulating valve operating handle 17, brake accumulator 18, accumulator pressure signaler 19, accumulator pressure gauge 26, brake pressure oil filter 20, first check valve 21, hand pump 22, second check valve 23, electric pump 24 and hydraulic pipeline;

[0024] Among them: the oil port S1 of oil tank 1 is connected with the oil suction port of hand pump 22, the oil port S2 of oil tank 1 is connected with the oil suction port of hydraulic pump 24, and the oil port R of oil tank 1 is system back oil port.Brake pressure regulating valve operating handle 17 is connected to the control rod of brake pressure regulating valve 5 by pressure valve operating cable 16, and brake safety valve operating handle 14 is connected to the control rod of rotor brake safety valve 11 by safety valve operating cable 13.The supply pressure port P of oil isolation device 6 is connected to the A outlet of brake pressure regulating valve 5, and the control port B of oil isolation device 6 is connected to brake small oil tank 15.The supply pressure port of accumulator is connected to the supply pressure port P of brake pressure regulating valve 5.

[0025] In the case of the specific design, in flight, the brake safety valve control handle 14 is in the b position, the control rod of the rotor brake safety valve 11 controlled by the safety valve control cable 13 is also in the b position, at this time, the P port and the A port of the rotor brake safety valve 11 are connected, the rotor brake safety valve 11 is in the on position, and the supply chamber of the rotor brake actuator 10 is connected with the brake small oil tank 15 to ensure that the supply chamber of the rotor brake actuator 10 is at atmospheric pressure.

[0026] In the case of the specific design, in flight, the brake pressure regulating valve control handle 17 is in the c position, the control rod of the brake pressure regulating valve 5 controlled by the pressure valve control cable 16 is also in the c position, at this time, the supply port P and the load port A of the brake pressure regulating valve 5 are disconnected, the load port A and the return port R of the brake pressure regulating valve 5 are connected, the brake pressure regulating valve 5 is in the off state; there is no pressure between the supply port P of the oil separation device 6 and the load port A of the brake pressure regulating valve 5, the control port B of the oil separation device 6 is connected with the brake small oil tank 15, there is no pressure difference between the a cavity and the b cavity of the oil separation device 6, and the piston of the oil separation device 6 does not act.

[0027] In the case of the specific design, in flight, if the brake pressure regulating valve 5 core appears misoperation fault, causing the brake pressure regulating valve 5 supply port P and the brake pressure regulating valve 5 load port A to be connected, the brake pressure regulating valve 5 return port R to be disconnected, then the oil separation device 6 supply port P and the brake pressure regulating valve 5 load port A exist high pressure, the oil separation device 6 a cavity pressure rises, and the piston moves under the action of pressure to compress the oil in the b cavity of the oil separation device 6; At this time, since the load port A of the brake pressure regulating valve 5 is connected with the pressure port P of the rotor brake safety valve 11, the load port A of the rotor brake safety valve 11, the brake small oil tank 15, the brake small oil tank 15 is connected with the atmosphere, and the supply chamber of the rotor brake actuator 10 has no hydraulic pressure, so as to avoid the occurrence of non-instruction rotor brake in the air;

[0028] In the case of the specific design, when the rotor is rapidly stopped, the brake safety valve handle 14 is first turned to position a, the control rod of the rotor brake safety valve 11 is also in position a through the safety valve control cable 13, at this time, the P port and the A port of the rotor brake safety valve 11 are disconnected, the rotor brake safety valve 11 is in the disconnected position, the supply chamber of the rotor brake actuator 10 is disconnected from the brake small oil tank 15, and the pipeline between the rotor brake actuator 10 and the rotor brake safety valve 11 is closed. At this time, the control port B of the oil separation device 6 is connected to the brake small oil tank 15, there is no pressure difference between the a chamber and the b chamber of the oil separation device 6, and the oil separation device 6 piston does not act; then, the brake pressure regulating valve handle 17 is turned to position b, the control rod of the brake pressure regulating valve 5 is also in position b through the pressure valve control cable 16, at this time, the supply port P and the load port A of the brake pressure regulating valve 5 are connected, and the load port A and the return port R of the brake pressure regulating valve 5 are disconnected; the brake pressure regulating valve 5 outputs the dynamic brake pressure to the supply port P of the oil separation device 6, the a chamber pressure of the oil separation device 6 increases, the oil separation device 6 piston moves to the b chamber, the control port B of the oil separation device 6 is closed, the oil separation device 6 is disconnected from the brake small oil tank 15, the b chamber of the oil separation device 6 is compressed, the load port A of the oil separation device 6 outputs the pressure to the supply chamber of the rotor brake actuator 10, the pressure value output by the load port A of the oil separation device 6 is equal to the dynamic brake pressure output by the brake pressure regulating valve 5, the rotor brake actuator 10 piston acts, the brake disc of the brake device is pressed against the transmission shaft flange, the rotor speed is rapidly reduced, and the rotor dynamic brake is realized.

[0029] In the specific design case, when the rotor brake is in the static brake position and the helicopter needs to be parked for a long time, the rotor brake hydraulic system needs to be operated. After the rotor is completely stopped, keep the brake safety valve operating handle 14 in the a position, and the control rod of the rotor brake safety valve 11 controlled by the safety valve operating steel cable 13 is also in the a position. At this time, the P port and the A port of the rotor brake safety valve 11 are disconnected, the rotor brake safety valve 11 is in the disconnected position, the supply chamber of the rotor brake actuator 10 is disconnected from the brake small oil tank 15, and the pipeline between the rotor brake actuator 10 and the rotor brake safety valve 11 is closed. Then, the brake pressure regulating valve operating handle 17 is directly operated from the b position to the a position, and the control rod of the brake pressure regulating valve 5 controlled by the pressure valve operating steel cable 16 is also in the a position. At this time, the supply port P and the load port A of the brake pressure regulating valve 5 are connected, and the load port A and the return port R of the brake pressure regulating valve 5 are disconnected. The brake pressure regulating valve 5 outputs the static brake pressure to the supply port P of the oil separation device 6, the a cavity pressure of the oil separation device 6a increases relative to the dynamic brake pressure, the oil separation device 6 piston moves to the b cavity, and the control port B of the oil separation device 6 remains closed. The oil separation device 6 is disconnected from the brake small oil tank 15, the b cavity of the oil separation device 6 is continuously compressed, the load port A of the oil separation device 6 outputs pressure to the supply chamber of the rotor brake actuator 10, and the pressure value output by the load port A of the oil separation device 6 is equal to the static brake pressure output by the brake pressure regulating valve 5. The rotor brake actuator 10 piston keeps the brake disc of the brake device pressed against the transmission shaft flange, maintains the rotor brake state, and realizes the rotor static brake.

[0030] In the specific design case, when the helicopter is parked in the static brake state, the rotor brake safety valve 11 and the brake pressure safety valve 25 and other hydraulic accessories inevitably have internal leakage, which will cause the pressure in the rotor brake actuator 10 to decrease, the oil separation device 6 piston to move to the b cavity, and the brake accumulator 18 to store high-pressure oil in the high-pressure cavity and reduce the pressure to the static brake pressure value through the brake pressure regulating valve 5. From the supply port P of the brake pressure regulating valve 5 to the load port A, and then to the a cavity of the oil separation device 6, the a cavity and the b cavity of the oil separation device 6 have equal piston areas and pressure values, the load port A of the oil separation device 6 is connected with the supply chamber of the rotor brake actuator 10, and the static brake pressure output by the brake pressure regulating valve 5 is transmitted to the supply chamber of the rotor brake actuator 10. Therefore, the brake accumulator 18 is used to compensate for the internal leakage of the brake system during the static brake process, and to maintain the static brake pressure in the supply chamber of the rotor brake actuator 10.

[0031] In the specific design case, if the helicopter rotor static brake state has been parked for a long time, the oil level rising information can be read through the oil level scale on the observation window of the brake small oil tank 15 to judge the leakage of the brake system and the pressure drop of the brake device; the pressure value P of the rotor brake actuator cylinder 10 pressure supply cavity can be checked through the pressure signal output by the brake pressure signaler 7, and in the static brake parking state, the pressure value P of the rotor brake actuator cylinder 10 pressure supply cavity should be equal to the static brake pressure Pset of the system; in addition, the pressure value PX of the brake accumulator 18 can be checked through the accumulator pressure gauge 26, and the pressure value PX of the brake accumulator 18 should be greater than the static brake pressure set by the system. Since the charging pressure of the brake accumulator 18 is close to the static brake pressure set by the system, if the pressure value PX of the brake accumulator 18 is less than or equal to the static brake pressure set by the system, it means that there is basically no available high-pressure oil liquid compensation system pressure change in the brake accumulator 18, at this time, the pressure output by the brake pressure signaler 7 should be zero, and then the brake accumulator 18 needs to be pressure compensated.

[0032] In the specific design case, the helicopter rotor static brake state has been parked for a long time, and the brake accumulator 18 needs to be pressure compensated, the on-board electric pump can be powered, then the electric pump will be triggered by the accumulator pressure signaler 19 to automatically pressure compensate the brake accumulator 18 to the maximum working pressure of the brake accumulator 18; when the on-board electric pump does not have starting conditions, the brake accumulator 18 can be artificially pressure compensated by the hand pump 22, and the value of the accumulator pressure gauge 26 is checked at the same time, and the pressure compensation pressure should not exceed the maximum working pressure of the brake accumulator 18;

[0033] In the specific design case, in the helicopter rotor static brake state, the increase of ambient temperature will cause the pressure in the rotor brake actuator cylinder 10 pressure supply section pipeline to rise, and after the pressure rises to the set value of the safety valve, the brake pressure safety valve 25 will open to release pressure and protect the rotor brake device and other accessories.

[0034] In the specific design case, during the rotor brake pressure supply, the a cavity and the b cavity in the oil liquid isolation device 6 have pressure transmission, which plays the role of hydraulic spring, can effectively reduce the pressure impact of the brake pressure regulating valve 5 when it is opened, and plays the role of protecting accessories and reducing impact wear.

[0035] In a specific design case, the oil isolation device 6 has the function of isolating the main system oil tank 1 from the key pollution source. The oil isolation device 6 divides the brake hydraulic system oil into two parts, one part is between the brake small oil tank 15 and the rotor brake actuating cylinder 10, and the other part is between the oil isolation device 6 and the oil tank 1. The oil between the two parts is isolated by the dynamic sealing ring of the piston in the oil isolation device 6. Therefore, the oil between the brake small oil tank 15, the rotor brake actuating cylinder 10 and the oil isolation device 6 can be regularly sampled and tested or replaced, while the rotor brake device as a key pollution source will not produce pollutants to the system oil between the oil isolation device 6 and the oil tank 1, and there is no need to replace the system oil, effectively isolating the pollution, reducing the waste of oil and maintenance work.

[0036] The above specific embodiments or cases are only used to explain the technical solutions of the present application, and are not limited to the present application. The parts not described in detail are regarded as conventional technical means or common knowledge in the art. It should be understood by those skilled in the art that based on the design idea of the present application, the technical solutions described in the foregoing embodiments can be modified or some or all of the technical features can be replaced by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A helicopter rotor brake hydraulic system, characterized in that, The hydraulic system consists of a hydraulic power source subsystem, a control unit, a contamination isolation unit, a redundancy module, and a load. The hydraulic power source subsystem outputs high-pressure hydraulic energy, which is controlled by the control unit and delivered to the inlet of the contamination isolation unit. The contamination isolation unit then transmits the pressure to the redundancy module. The redundancy module responds to control commands issued from the cockpit to open or close the oil circuit for transmitting pressure to the load. The hydraulic power source subsystem includes an oil tank (1), a return oil filter (2), a bypass valve (3), a return oil check valve (4), a brake accumulator (18), an accumulator pressure signal device (19), an accumulator pressure gauge (26), a brake pressure oil filter (20), a first check valve (21), a hand pump (22), a second check valve (23), and an electric pump (24). The electric pump (24) draws oil from the oil tank (1), and the oil passes through the second check valve (23) and is filtered by the brake pressure oil filter (20) before entering the brake accumulator (18) for energy storage. The oil flows into the rotor brake pressure control unit. When the brake pressure is released, the return oil flows back to the oil tank (1) through the return oil check valve (4) and the return oil filter (2). When the electric pump cannot be started after being parked on the ground for a long time, the hand pump (22) can also draw oil from the oil tank (1) to replenish the pressure of the brake accumulator (18). The first check valve (21) and the second check valve (23) can prevent the oil from flowing back into the hand pump (22) or the electric pump (24) to avoid damaging the pump body. When the flow resistance of the return oil filter (2) increases to a certain value, the bypass valve (3) is opened to prevent the oil from not returning. The accumulator pressure signal (19) is connected to the air chamber of the brake accumulator (18). When the pressure of the brake accumulator (18) is lower than the set value, the electric pump (24) is automatically triggered to start and pressurize the accumulator to the set pressure. The set charging pressure of the accumulator is higher than the rotor static brake pressure value Pstatic. The control unit includes a brake pressure regulating valve (5), a pressure valve operating cable (16), and a brake pressure regulating valve operating handle (17). The driver moves the brake pressure regulating valve operating handle (17) to different positions in the cockpit and controls the valve core movement and opening area of ​​the brake pressure regulating valve (5) through the pressure valve operating cable (16) to achieve different brake pressure values ​​for dynamic braking and static braking. The redundancy module includes a rotor brake safety valve (11), a brake safety valve micro switch (12), a safety valve operating cable (13), a brake safety valve operating handle (14), and a brake oil tank (15). The driver operates the safety valve operating cable (13) in the cockpit and moves it to different positions. The rotor brake safety valve (11) is in the safe position or the open position. When the rotor brake safety valve (11) is in the safe position, the rotor brake device is connected to the brake oil tank (15). When the rotor brake safety valve (11) is in the open position, the pressure between the rotor brake device and the oil isolation device (6) is connected and transmitted. At this time, the brake safety valve micro switch (12) is triggered. The oil port S1 of the oil tank (1) is connected to the oil suction port of the hand pump (22), the oil port S2 of the oil tank (1) is connected to the oil suction port of the electric pump (24), and the oil port R of the oil tank (1) is the system return port; the brake pressure regulating valve operating handle (17) is connected to the control rod of the brake pressure regulating valve (5) through the pressure valve operating cable (16), and the brake safety valve operating handle (14) is connected to the control rod of the rotor brake safety valve (11) through the safety valve operating cable (13); the pressure supply port P of the oil isolation device (6) is connected to the A outlet of the brake pressure regulating valve (5), and the control port B of the oil isolation device (6) is connected to the brake small oil tank (15); the pressure supply port of the accumulator is connected to the pressure supply port P of the brake pressure regulating valve (5).

2. The helicopter rotor brake hydraulic system as described in claim 1, characterized in that, When the return oil filter (2) is used in combination with the bypass valve (3), the return oil flows through the bypass valve (3) when the flow resistance of the return oil filter (2) exceeds the design flow resistance of the bypass valve (3).

3. The helicopter rotor brake hydraulic system as described in claim 1, characterized in that, The pollution isolation unit is achieved by using an oil isolation device (6); by using an isolation device between the oil inlet and the oil outlet, the oil between the rotor brake device and the oil tank is not connected.

4. The helicopter rotor brake hydraulic system as described in claim 3, characterized in that, The oil isolation device (6) has the function of isolating the main system oil tank (1) from the key pollution source; the oil isolation device (6) divides the brake hydraulic system oil into two parts, one part is between the brake small oil tank (15) and the rotor brake actuator cylinder (10), and the other part is the system oil between the oil isolation device (6) and the oil tank (1); the oil between the two parts is isolated by the dynamic sealing ring of the piston inside the oil isolation device (6).

5. The helicopter rotor brake hydraulic system as described in claim 1, characterized in that, The brake oil tank (15) is an open type, and the oil tank is connected to the atmosphere. When the rotor brake device breaks the pipeline, the air bubbles will automatically float to the upper part of the brake oil tank (15).

6. The helicopter rotor brake hydraulic system as described in claim 5, characterized in that, The brake oil tank (15) is equipped with an oil level observation window, oil level scale lines and markings, which are used to observe the oil level when the rotor is parked for a long time.

Images