Helicopter hydraulic system intelligent combination valve group and control method thereof

Abstract

The invention discloses an intelligent combination valve group of a helicopter hydraulic system and a control method of the intelligent combination valve group. According to the valve group, an oil port P1 and an oil port T1 of a two-position six-way hydraulic control reversing valve are communicated with an oil inlet and an oil return port of a main system respectively to form a main system oil way, and an oil port P2 and an oil port T2 of the two-position six-way hydraulic control reversing valve are communicated with an oil inlet and an oil return port of a standby system respectively to form a standby system oil way; the working oil ports are respectively communicated with internal oil ways of the main rotor steering engine and the tail rotor steering engine through the first normally-open two-position three-way hydraulic control reversing valve and the second normally-open two-position three-way hydraulic control reversing valve to form a main rotor steering engine oil way and a tail rotor steering engine oil way, and the three normally-closed two-position three-way electromagnetic valves are respectively used for controlling the two-position six-way hydraulic control reversing valve, the first normally-open two-position three-way hydraulic control reversing valve and the second normally-open two-position three-way hydraulic control reversing valve; and the four sensors are respectively used for monitoring pressure signals of oil ways of the main system, the standby system, the main rotor steering engine and the tail rotor steering engine. Hydraulic control pilot active control over pressure switching of a large-flow main and standby system is achieved, and rapid cutting-off is achieved when a load oil way breaks and loses pressure.

Description

Technical Field

[0001] The present invention relates to the technical field of helicopter hydraulic control, and particularly to an intelligent combined valve group for a helicopter hydraulic system and a control method thereof. Background Art

[0002] As a redundancy management component of a helicopter hydraulic system, the main functions of the combined valve group include:

[0003] ① Switching to the standby hydraulic system when the main hydraulic system loses pressure;

[0004] ② Filtering the inlet oil and return oil of the main hydraulic system;

[0005] ③ Overpressure protection for the main hydraulic system;

[0006] ④ Cutting off when the load circuit loses pressure.

[0007] At present, the main and standby system pressure switching mode of the combined valve group of the helicopter hydraulic system is mainly mechanical-hydraulic control type. Its pilot oil circuit is complex, and mis-switching may occur when facing external pressure disturbances. Moreover, when the leakage degree of the load oil circuit is relatively large, the rapidly decreasing pressure of the main system oil circuit causes the main and standby systems to switch pressures, resulting in oil loss in the standby system. In addition, the leakage cut-off of the main rotor rudder oil circuit and the tail rotor rudder oil circuit is mainly controlled by multi-stage low oil level switches in the hydraulic oil tank of the main hydraulic system. When the rudder oil circuit leaks and the liquid level in the tank reaches a specific position, the first-stage and second-stage low oil level switches are triggered respectively, and corresponding cut-off operations are performed. Since the control logic of the low oil level switch is to cut off the tail rotor rudder oil circuit at the first stage and the main rotor rudder oil circuit at the second stage, when the main rotor rudder oil circuit breaks down and loses pressure, the existing multi-stage low oil level switch control method will cause a large amount of unnecessary oil loss.

[0008] In addition, there are certain defects in the signal monitoring and control of the combined valve group of the current helicopter hydraulic system:

[0009] First, as the core of the redundancy switching of the combined valve group, the pressure switching main valve lacks position signal monitoring, and the actual switching state of the system is not intuitively displayed;

[0010] Second, pressure switches are provided on the main rotor rudder oil circuit and the tail rotor rudder oil circuit, but they do not participate in the actual cut-off control, and the state after cut-off is difficult to know;

[0011] Third, although temperature and pressure monitoring sensors are provided on the oil circuits of the main hydraulic system and the standby hydraulic system, the collected signals are only used as observed values and do not participate in the actual control. Summary of the Invention

[0012] The object of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide an intelligent combined valve group for a helicopter hydraulic system and its control method. The present invention realizes the integrated monitoring of temperature and pressure of the main hydraulic system and the standby hydraulic system, the intuitive observation of the system switching and cut-off states, the hydraulic control pilot active control of the large-flow main and standby system pressure switching, and the rapid cut-off when the load oil circuit ruptures and loses pressure.

[0013] To achieve the above object, the technical solutions adopted by the present invention are as follows:

[0014] I. An intelligent combined valve group for a helicopter hydraulic system

[0015] The intelligent combined valve group for the helicopter hydraulic system includes:

[0016] A two-position six-way hydraulic control reversing valve, the P1 oil port and the T1 oil port are respectively connected to the main system oil inlet and the return oil port to form a main system oil circuit, and the P2 oil port and the T2 oil port are respectively connected to the standby system oil inlet and the return oil port to form a standby system oil circuit;

[0017] A first normally open two-position three-way hydraulic control reversing valve, the A oil port and the B oil port are respectively connected to the A oil port of the two-position six-way hydraulic control reversing valve and the oil inlet of the main rotor servo, and the T oil port is respectively connected to the return oil port of the main rotor servo and the B oil port of the two-position six-way hydraulic control reversing valve to form a main rotor servo oil circuit;

[0018] A second normally open two-position three-way hydraulic control reversing valve, the A oil port and the B oil port are respectively connected to the A oil port of the two-position six-way hydraulic control reversing valve and the oil inlet of the tail rotor servo, and the T oil port is respectively connected to the return oil port of the tail rotor servo and the B oil port of the two-position six-way hydraulic control reversing valve to form a tail rotor servo oil circuit;

[0019] Three normally closed two-position three-way solenoid valves, which are respectively used to control the two-position six-way hydraulic control reversing valve, the first normally open two-position three-way hydraulic control reversing valve and the second normally open two-position three-way hydraulic control reversing valve;

[0020] A sensor module, including two temperature and pressure integrated sensors, which are respectively used to monitor the temperature and pressure signals of the main system and the standby system oil circuits, two pressure sensors, which are respectively used to monitor the pressure signals of the main rotor servo oil circuit and the tail rotor servo oil circuit, and a displacement sensor, which is built in the two-position six-way hydraulic control reversing valve and is used to monitor the spool position.

[0021] For the first normally open two-position three-way hydraulic control reversing valve and the second normally open two-position three-way hydraulic control reversing valve, in the working state, the A oil port is connected to the B oil port, and the T oil port is closed. In the off state, the A oil port is closed, and the B oil port is connected to the T oil port. For the two-position six-way hydraulic control reversing valve, in the working state, the P1 oil port is connected to the A oil port, the T1 oil port is connected to the B oil port, and the P2 oil port and the T2 oil port are closed. In the off state, the P2 oil port is connected to the A oil port, the T2 oil port is connected to the B oil port, and the P1 oil port and the T1 oil port are closed.

[0022] The three normally closed two-position three-way solenoid valves are respectively the first normally closed two-position three-way solenoid valve, the second normally closed two-position three-way solenoid valve, and the third normally closed two-position three-way solenoid valve. The first normally closed two-position three-way solenoid valve is used to control the X hydraulic control port of the two-position six-way hydraulic control reversing valve, and the C control oil port is connected to the X hydraulic control port of the two-position six-way hydraulic control reversing valve. The second normally closed two-position three-way solenoid valve is used to control the X hydraulic control port of the first normally open two-position three-way hydraulic control reversing valve, and the C control oil port is connected to the X hydraulic control port of the first normally open two-position three-way hydraulic control reversing valve. The third normally closed two-position three-way solenoid valve is used to control the X hydraulic control port of the second normally open two-position three-way hydraulic control reversing valve, and the C control oil port is connected to the X hydraulic control port of the second normally open two-position three-way hydraulic control reversing valve. After each normally closed two-position three-way solenoid valve is powered on, the C control oil port is connected to the P oil port, and the connected hydraulic control reversing valve is switched to the off state.

[0023] Further, the valve group further includes a control unit, and the control unit is used to control the on-off of the three normally closed two-position three-way solenoid valves according to the real-time signals collected by two temperature-pressure integrated sensors and two pressure sensors. The control unit is electrically connected to the three normally closed two-position three-way solenoid valves respectively, and is communicatively connected to the two temperature-pressure integrated sensors and the two pressure sensors respectively.

[0024] Specifically, the two temperature-pressure integrated sensors are respectively the first temperature-pressure integrated sensor and the second temperature-pressure integrated sensor arranged between the two-position six-way hydraulic control reversing valve and the main system oil inlet, and between the two-position six-way hydraulic control reversing valve and the standby system oil inlet. The two pressure sensors are respectively the first pressure sensor and the second pressure sensor arranged between the first normally open two-position three-way hydraulic control reversing valve and the oil inlet of the main propeller rudder machine, and between the second normally open two-position three-way hydraulic control reversing valve and the oil inlet of the tail propeller rudder machine.

[0025] Further, the valve group further includes a first one-way valve, a fourth one-way valve, a relief valve, a first filter screen, a second filter screen and a bypass valve; a first one-way valve, a first filter screen and a first temperature and pressure integrated sensor are sequentially arranged on the main system oil inlet pipeline between the main system oil inlet and the P1 oil port of the two-position six-way hydraulically controlled directional valve; a second filter screen and a fourth one-way valve are sequentially arranged on the main system oil return pipeline between the main system oil return port and the T1 oil port of the two-position six-way hydraulically controlled directional valve, and the second filter screen is in parallel with the bypass valve; a relief valve is arranged between the main system oil inlet and the oil return pipeline, the inlet end of the relief valve is arranged between the first one-way valve and the first filter screen, and the outlet end is arranged between the T1 oil port of the two-position six-way hydraulically controlled directional valve and the second filter screen.

[0026] Further, the valve group further includes a second one-way valve and a third one-way valve; the A oil port of the second one-way valve is respectively communicated with the T oil port of the first normally open two-position three-way hydraulically controlled directional valve and the oil return port of the main propeller rudder machine, and the B oil port is communicated with the B oil port of the two-position six-way hydraulically controlled directional valve; the A oil port of the third one-way valve is respectively communicated with the T oil port of the second normally open two-position three-way hydraulically controlled directional valve and the oil return port of the tail rotor rudder machine, and the B oil port is communicated with the B oil port of the two-position six-way hydraulically controlled directional valve.

[0027] II. A control method applied to the intelligent combined valve group of the above helicopter hydraulic system

[0028] The control method includes the following steps:

[0029] The first step, open-circuit detection: detect whether the pressure signal of the first temperature and pressure integrated sensor is greater than zero; if it is greater than zero, set the pressure switching decision value as the pressure signal of the first temperature and pressure integrated sensor; otherwise, take the larger value of the pressure signals of the first pressure sensor and the second pressure sensor plus a preset compensation value as the pressure switching decision value.

[0030] The second step, forced cut-off detection: judge whether the pressure switching decision value is higher than a preset forced cut-off threshold value, if it is higher than the forced cut-off threshold value, execute the third step; otherwise, execute the sixth step.

[0031] The third step, pressure loss detection: judge whether the pressure switching decision value is lower than a preset pressure loss switching threshold value, if it is lower than the pressure loss switching threshold value, execute the fourth step; otherwise, execute the tenth step.

[0032] The fourth step, pressure mutation detection: start the pressure loss discrimination delay, after the delay ends, update the pressure switching decision value according to the real-time pressure signal, and judge again whether the pressure switching decision value is lower than the preset pressure loss switching threshold value, if it is lower than the pressure loss switching threshold value, execute the fifth step; otherwise, execute the tenth step.

[0033] Step 5: Determine whether the pressure switching decision value is lower than the preset first leakage cut-off threshold. If it is lower than the first leakage cut-off threshold, execute Step 6; otherwise, execute Step 14;

[0034] Step 6: Energize the second normally closed two-way three-way solenoid valve. After energization, delay. Update the pressure switching decision value according to the real-time pressure signal. Determine whether the pressure switching decision value is lower than the first leakage cut-off threshold. If it is lower than the first leakage cut-off threshold, give a status alarm of "main system pressure loss" and execute Step 7; otherwise, give a status alarm of "main propeller and rudder oil circuit rupture and pressure loss" and execute Step 14;

[0035] Step 7: Energize the first normally closed two-way three-way solenoid valve and de-energize the second normally closed two-way three-way solenoid valve. After de-energization, delay;

[0036] Step 8: Update the pressure switching decision value according to the real-time pressure signal. Determine whether the pressure switching decision value is higher than the preset recovery pressure threshold. If it is lower than the recovery pressure threshold, the system is in the standby system oil supply state, keep the status alarm of "main system pressure loss", and the valve group continuously monitors the main system pressure and re-enters Step 8; otherwise, cancel the status alarm of "main system pressure loss" and execute Step 9;

[0037] Step 9: De-energize the first normally closed two-way three-way solenoid valve and return to Step 1;

[0038] Step 10: Small leakage detection: Detect whether the hydraulic oil level of the main system is lower than the first oil level control value. If it is lower than the first oil level control value, give a status alarm of "oil circuit leakage" and execute Step 11; otherwise, return to Step 1;

[0039] Step 11: Energize the third normally closed two-way three-way solenoid valve. After energization, delay;

[0040] Step 12: Detect whether the hydraulic oil level of the main system is lower than the second oil level control value. If it is lower than the second oil level control value, give a status alarm of "continuous oil circuit leakage" and execute Step 13; otherwise, re-enter Step 12;

[0041] Step 13: Energize the second normally closed two-way three-way solenoid valve and the process ends;

[0042] Step 14: Determine whether the pressure switching decision value is lower than the second leakage cut-off threshold. If it is lower than the second leakage cut-off threshold, execute Step 15; otherwise, execute Step 10;

[0043] Step 15: Energize the third normally closed two-position three-way solenoid valve. After energization, delay. Update the pressure switching decision value according to the real-time pressure signal. Determine whether the pressure switching decision value is lower than the second leakage cut-off threshold. If it is lower than the second leakage cut-off threshold, give a status alarm of "main system pressure loss" and execute Step 16; otherwise, give a status alarm of "pressure loss due to rupture of the tail rotor steering gear oil circuit" and execute Step 10.

[0044] Step 16: Energize the first normally closed two-position three-way solenoid valve, de-energize the second normally closed two-position three-way solenoid valve 2 and the third normally closed two-position three-way solenoid valve. After de-energization, delay and execute Step 8.

[0045] Specifically, the respective thresholds from low to high are: forced cut-off threshold, first leakage cut-off threshold, second leakage cut-off threshold, pressure loss switching threshold, restored pressure threshold, and rated working pressure.

[0046] Specifically, in Step 6, Step 7, Step 9, Step 11, Step 13, Step 15, and Step 16, after energizing or de-energizing any normally closed two-position three-way solenoid valve, delay until the corresponding hydraulic control directional valve completes the commutation, and then proceed to the next operation.

[0047] The beneficial effects of the present invention are:

[0048] 1. In the present invention, the pressure switching configuration of the hydraulic control pilot type main and standby system based on the dual-redundancy micro cartridge solenoid valve simplifies the pilot oil circuit for the pressure switching of the main and standby systems, facilitating the active control of the pressure switching of the large-flow main and standby systems; the dual-redundancy micro cartridge solenoid valve ensures the reliability of the pressure switching of the main and standby systems from the hardware structure, and the comprehensive decision-making of the three pressure signals, namely the main system pressure signal detected by the first temperature and pressure integrated sensor, the main rotor oil circuit pressure signal detected by the first pressure sensor, and the tail rotor oil circuit pressure signal detected by the second pressure sensor, ensures the reliability of the pressure switching of the main and standby systems from the software control. The spool of the pressure switching control valve of the main and standby systems is equipped with a displacement sensor, facilitating the direct observation of the switching state of the system.

[0049] 2. In the present invention, when the leakage degree of the load oil circuit is small, the load leakage discrimination and cut-off control are carried out through the main system hydraulic oil level signal. When the load oil circuit bursts and loses pressure, the corresponding load oil circuit cut-off control is carried out through different set pressure thresholds. An appropriate forced cut-off threshold is set to cut off the load oil circuit in advance to avoid the system pressure being too low to push the spring of the hydraulic control valve, that is, the load cannot be cut off. Different from the original pressure switch, pressure sensors are added to the main propeller rudder oil circuit and the tail propeller rudder oil circuit respectively for continuous pressure signal monitoring. The hydraulic control pilot type load oil circuit cut-off configuration with dual-redundancy micro cartridge valves is adopted, which is convenient for the active control of the load oil circuit leakage cut-off, and can quickly respond when the load oil circuit bursts and loses pressure, without waiting for the hydraulic oil level signal, immediately cut off the burst and pressure-lost oil circuit, avoid a large amount of oil loss, and ensure the normal operation of the non-burst oil circuit; the dual-redundancy micro cartridge valves ensure the reliability of the load oil circuit cut-off from the hardware structure. The first pressure sensor and the second pressure sensor of the load oil circuit can be used as redundant pressure signals for the main and standby system pressure switching and cut-off control when the pressure signal of the first temperature and pressure integrated sensor fails. After the load is cut off, the actual cut-off situation can be directly judged according to the corresponding pressure sensor signal.

[0050] 3. In the present invention, the check valve adopts an embedded check valve, and the component composition of the combined valve group of the helicopter hydraulic system is simplified through the micro cartridge valve, the embedded check valve and the multi-physical quantity integrated sensor (temperature and pressure integrated sensor), and the integration degree is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 is the hydraulic schematic diagram of the present invention.

[0052] Figure 2 is the comprehensive decision logic diagram of the present invention.

[0053] Figure 3 is the test result diagram of the embodiment of the present invention under various fault forms; among them, (a) is a small-amplitude pressure mutation, (b) is a large-amplitude pressure mutation, (c) is the burst and pressure loss of the load 1 oil circuit, (d) is the burst and pressure loss of the load 2 oil circuit, (e) is a certain degree of pressure loss of the main system, and (f) is the fluctuation and recovery after the main system loses pressure.

[0054] In the figure: 1 - First normally closed two - position three - way solenoid valve, 2 - Second normally closed two - position three - way solenoid valve, 3 - Third normally closed two - position three - way solenoid valve, 4 - Two - position six - way hydraulic control reversing valve with built - in displacement sensor, 5 - First normally open two - position three - way hydraulic control valve, 6 - Second normally open two - position three - way hydraulic control valve, 7 - First check valve, 8 - Second check valve, 9 - Third check valve, 10 - Fourth check valve, 11 - Relief valve, 12 - First filter screen, 13 - Second filter screen, 14 - Bypass valve, 15 - First temperature - pressure integrated sensor, 16 - Second temperature - pressure integrated sensor, 17 - First pressure sensor, 18 - Second pressure sensor. Detailed implementation mode

[0055] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0056] The first aspect of the present invention provides an intelligent combined valve group for a helicopter hydraulic system.

[0057] As Figure 1 shown, in the present invention, the intelligent combined valve group for the helicopter hydraulic system mainly includes the following components:

[0058] The two - position six - way hydraulic control reversing valve 4, the P1 oil port and the T1 oil port are respectively connected to the main system oil inlet and the main system oil return port to form the main system oil circuit, and the P2 oil port and the T2 oil port are respectively connected to the standby system oil inlet and the standby system oil return port to form the standby system oil circuit;

[0059] The first normally open two - position three - way hydraulic control valve 5, the A oil port and the B oil port are respectively connected to the A oil port of the two - position six - way hydraulic control reversing valve 4 and the oil inlet of the main rotor servo, and the T oil port is respectively connected to the oil return port of the main rotor servo and the B oil port of the two - position six - way hydraulic control reversing valve 4 to form the main rotor servo oil circuit;

[0060] The second normally open two - position three - way hydraulic control valve 6, the A oil port and the B oil port are respectively connected to the A oil port of the two - position six - way hydraulic control reversing valve 4 and the oil inlet of the tail rotor servo, and the T oil port is respectively connected to the oil return port of the tail rotor servo and the B oil port of the two - position six - way hydraulic control reversing valve 4 to form the tail rotor servo oil circuit;

[0061] Three normally closed two - position three - way solenoid valves are respectively used to control the two - position six - way hydraulic control reversing valve 4, the first normally open two - position three - way hydraulic control valve 5 and the second normally open two - position three - way hydraulic control valve 6;

[0062] The sensor module includes: two temperature - pressure integrated sensors, which respectively monitor the temperature and pressure signals of the main system and the standby system oil circuits; two pressure sensors, which respectively monitor the pressure signals of the main rotor servo and the tail rotor servo oil circuits; and a displacement sensor, which is built in the two - position six - way hydraulic control reversing valve 4 to monitor the spool position.

[0063] Preferably, the normally-closed two-position three-way solenoid valve is of a dual-redundancy micro cartridge type.

[0064] Specifically, the three normally-closed two-position three-way solenoid valves are respectively a first normally-closed two-position three-way solenoid valve 1, a second normally-closed two-position three-way solenoid valve 2, and a third normally-closed two-position three-way solenoid valve 3. After each normally-closed two-position three-way solenoid valve is energized, the C control oil port is connected to the P oil port, and the hydraulic control directional valves (two-position six-way hydraulic control directional valve 4, first normally-open two-position three-way hydraulic control directional valve 5, second normally-open two-position three-way hydraulic control directional valve 6) connected thereto are switched from the working state to the off state.

[0065] For the first normally-open two-position three-way hydraulic control directional valve 5 and the second normally-open two-position three-way hydraulic control directional valve 6, in the working state, the A oil port is connected to the B oil port, and the T oil port is closed; in the off state, the A oil port is closed, and the B oil port is connected to the T oil port.

[0066] For the two-position six-way hydraulic control directional valve 4, in the working state, the P1 oil port is connected to the A oil port, the T1 oil port is connected to the B oil port, and the P2 oil port and the T2 oil port are closed; in the off state, the P2 oil port is connected to the A oil port, the T2 oil port is connected to the B oil port, and the P1 oil port and the T1 oil port are closed.

[0067] Specifically, the first normally-closed two-position three-way solenoid valve 1 is used to control the X hydraulic control port of the two-position six-way hydraulic control directional valve 4. The C control oil port is connected to the X hydraulic control port of the two-position six-way hydraulic control directional valve 4. The P oil port and the R oil port are respectively connected to the standby system inlet port and the standby system return port. After being energized and opened, the C control oil port is connected to the P oil port.

[0068] Specifically, the second normally-closed two-position three-way solenoid valve 2 is used to control the X hydraulic control port of the first normally-open two-position three-way hydraulic control directional valve 5. The C control oil port is connected to the X hydraulic control port of the first normally-open two-position three-way hydraulic control directional valve 5. The P oil port and the R oil port are respectively connected to the A oil port and the B oil port of the two-position six-way hydraulic control directional valve 4. After being energized and opened, the C control oil port is connected to the P oil port.

[0069] Specifically, the third normally-closed two-position three-way solenoid valve 3 is used to control the X hydraulic control port of the second normally-open two-position three-way hydraulic control directional valve 6. The C control oil port is connected to the X hydraulic control port of the second normally-open two-position three-way hydraulic control directional valve 6. The P oil port and the R oil port are respectively connected to the A oil port and the B oil port of the two-position six-way hydraulic control directional valve 4. After being energized and opened, the C control oil port is connected to the P oil port.

[0070] Further, the valve group further includes a control unit, which is used to make a comprehensive decision and judgment based on the real-time pressure signals collected by two temperature-pressure integrated sensors and two pressure sensors, and then control the on-off of the three normally-closed two-position three-way solenoid valves; the control unit is electrically connected to the three normally-closed two-position three-way solenoid valves respectively, and is communicatively connected to the two temperature-pressure integrated sensors and the two pressure sensors respectively.

[0071] Specifically, the two temperature and pressure integrated sensors are respectively the first temperature and pressure integrated sensor 15 and the second temperature and pressure integrated sensor 16, which are arranged between the P1 oil port of the two-position six-way hydraulic control reversing valve 4 and the main system oil inlet, and between the P2 oil port of the two-position six-way hydraulic control reversing valve 4 and the standby system oil inlet.

[0072] Specifically, the two pressure sensors are respectively the first pressure sensor 17 and the second pressure sensor 18, which are arranged between the B oil port of the first normally open two-position three-way hydraulic control reversing valve 5 and the oil inlet of the main propeller and rudder machine, and between the B oil port of the second normally open two-position three-way hydraulic control reversing valve 6 and the oil inlet of the tail propeller and rudder machine.

[0073] Further, the valve group further includes a first check valve 7, a fourth check valve 10, a relief valve 11, a first filter screen 12, a second filter screen 13 and a bypass valve 14; the first check valve 7, the first filter screen 12 and the first temperature and pressure integrated sensor 15 are sequentially arranged on the main system oil inlet oil path between the main system oil inlet and the P1 oil port of the two-position six-way hydraulic control reversing valve 4; the second filter screen 13 and the fourth check valve 10 are sequentially arranged on the main system oil return oil path between the main system oil return port and the T1 oil port of the two-position six-way hydraulic control reversing valve 4, and the second filter screen 13 is in parallel with the bypass valve 14; a relief valve 11 is arranged between the main system oil inlet and the oil return oil path, the inlet end of the relief valve 11 is arranged between the first check valve 7 and the first filter screen 12, and the outlet end is arranged between the T1 oil port of the two-position six-way hydraulic control reversing valve 4 and the second filter screen 13.

[0074] Further, the valve group further includes a second check valve 8 and a third check valve 9; the A oil port of the second check valve 8 is respectively communicated with the T oil port of the first normally open two-position three-way hydraulic control reversing valve 5 and the oil return port of the main propeller and rudder machine, and the B oil port is communicated with the B oil port of the two-position six-way hydraulic control reversing valve 4; the A oil port of the third check valve 9 is respectively communicated with the T oil port of the second normally open two-position three-way hydraulic control reversing valve 6 and the oil return port of the tail propeller and rudder machine, and the B oil port is communicated with the B oil port of the two-position six-way hydraulic control reversing valve 4.

[0075] The second aspect of the present invention provides a control method applied to the intelligent combined valve group of the above helicopter hydraulic system.

[0076] As Figure 2 shown, the control method of the present invention includes the following steps:

[0077] First step, open circuit detection: detect whether the pressure signal of the first temperature and pressure integrated sensor 15 is greater than zero; if it is greater than zero, set the pressure switching decision value as the pressure signal of the first temperature and pressure integrated sensor 15; otherwise, take the larger value of the pressure signals of the first pressure sensor 17 and the second pressure sensor 18 plus a preset compensation value as the pressure switching decision value;

[0078] In the specific implementation of the present invention, the pressure difference when the two-position six-way hydraulic control reversing valve 4 and the first normally open two-position three-way hydraulic control reversing valve 5 pass the rated flow rate is set as the compensation value;

[0079] Second step, forced cut-off detection: Determine whether the pressure switching decision value is higher than the preset forced cut-off threshold. If it is higher than the forced cut-off threshold, execute the third step; otherwise, execute the sixth step;

[0080] Optionally, the forced cut-off threshold can be set according to the spring pre-tightening force and the area of the valve core end face of the two-position six-way hydraulic control reversing valve 4, the first normally open two-position three-way hydraulic control reversing valve 5, and the second normally open two-position three-way hydraulic control reversing valve 6.

[0081] Third step, pressure loss detection: Determine whether the pressure switching decision value is lower than the preset pressure loss switching threshold. If it is lower than the pressure loss switching threshold, execute the fourth step; otherwise, execute the tenth step;

[0082] Optionally, the pressure loss switching threshold is set according to the actual load requirement and the rated working pressure of the system.

[0083] Fourth step, pressure mutation detection: Start the pressure loss discrimination delay. After the delay ends, update the pressure switching decision value according to the real-time pressure signal (no need to perform open circuit detection again), and determine again whether the pressure switching decision value is lower than the preset pressure loss switching threshold. If it is lower than the pressure loss switching threshold, execute the fifth step; otherwise, execute the tenth step;

[0084] Optionally, the duration of the pressure loss discrimination delay is set according to relevant pressure mutation criteria or actual working conditions;

[0085] Fifth step, determine whether the pressure switching decision value is lower than the preset first leakage cut-off threshold. If it is lower than the first leakage cut-off threshold, execute the sixth step; otherwise, execute the fourteenth step;

[0086] Sixth step, energize the second normally closed two-position three-way solenoid valve 2. After energization, delay, update the pressure switching decision value according to the real-time pressure signal, and determine whether the pressure switching decision value is lower than the first leakage cut-off threshold. If it is lower than the first leakage cut-off threshold, give a status alarm of "main system pressure loss", execute the seventh step; otherwise, give a status alarm of "main propeller and rudder oil circuit rupture and pressure loss", execute the fourteenth step;

[0087] Seventh step, energize the first normally closed two-position three-way solenoid valve 1, de-energize the second normally closed two-position three-way solenoid valve 2, and delay after de-energization;

[0088] Step 8: Update the pressure switching decision value according to the real-time pressure signal, and determine whether the pressure switching decision value is higher than the preset recovery pressure threshold. If it is lower than the recovery pressure threshold, the system is in the standby system oil supply state, maintaining the status alarm "main system pressure loss", and the valve group continuously monitors the main system pressure and re-enters Step 8; otherwise, cancel the status alarm "main system pressure loss" and execute Step 9;

[0089] Optionally, the recovery pressure threshold is slightly lower than the rated working pressure.

[0090] Step 9: Cut off the power supply of the first normally closed two-position three-way solenoid valve 1 and return to Step 1;

[0091] Step 10: Small leakage detection: Detect whether the hydraulic oil level of the main system is lower than the first oil level control value. If it is lower than the first oil level control value, the status alarm "oil leakage" is given and Step 11 is executed; otherwise, return to Step 1;

[0092] Step 11: Energize the third normally closed two-position three-way solenoid valve 3 and delay after energization;

[0093] Step 12: Detect whether the hydraulic oil level of the main system is lower than the second oil level control value. If it is lower than the second oil level control value, the status alarm "continuous oil leakage" is given and Step 13 is executed; otherwise, maintain the status alarm "oil leakage" and re-enter Step 12; The second oil level control value is lower than the first oil level control value;

[0094] Step 13: Energize the second normally closed two-position three-way solenoid valve 2 and the process ends;

[0095] Step 14: Determine whether the pressure switching decision value is lower than the second leakage cut-off threshold. If it is lower than the second leakage cut-off threshold, execute Step 15; otherwise, execute Step 10;

[0096] Step 15: Energize the third normally closed two-position three-way solenoid valve 3 and delay after energization. Update the pressure switching decision value according to the real-time pressure signal, and determine whether the pressure switching decision value is lower than the second leakage cut-off threshold. If it is lower than the second leakage cut-off threshold, the status alarm "main system pressure loss" is given and Step 16 is executed; otherwise, the status alarm "tail rotor steering gear oil circuit rupture and pressure loss" is given and Step 10 is executed;

[0097] Step 16: Energize the first normally closed two-position three-way solenoid valve 1, cut off the power supply of the second normally closed two-position three-way solenoid valve 2 and the third normally closed two-position three-way solenoid valve 3, delay after power-off, and execute Step 8.

[0098] In the above process, the thresholds from low to high are: forced cut-off threshold, first leakage cut-off threshold, second leakage cut-off threshold, pressure loss switching threshold, recovery pressure threshold, rated working pressure.

[0099] In specific implementation, in the sixth, seventh, ninth, eleventh, thirteenth, fifteenth, and sixteenth steps, after any normally-closed two-position three-way solenoid valve is energized or de-energized, it is delayed until the corresponding hydraulically-controlled directional valve completes the commutation, and then the next operation is carried out.

[0100] The specific embodiments of the present invention are as follows:

[0101] Embodiment

[0102] As Figure 1 shown, this embodiment provides an intelligent combined valve group for a helicopter hydraulic system, including: a first normally-closed two-position three-way solenoid valve 1, a second normally-closed two-position three-way solenoid valve 2, a third normally-closed two-position three-way solenoid valve 3, a two-position six-way hydraulically-controlled directional valve 4 with an internal displacement sensor, a first normally-open two-position three-way hydraulically-controlled valve 5, a second normally-open two-position three-way hydraulically-controlled valve 6, a first check valve 7, a second check valve 8, a third check valve 9, a fourth check valve 10, a relief valve 11, a first filter screen 12, a second filter screen 13, a bypass valve 14, a first temperature and pressure integrated sensor 15, a second temperature and pressure integrated sensor 16, a first pressure sensor 17, and a second pressure sensor 18.

[0103] The A oil port of the first one-way valve 7 is connected to the main system oil inlet, and the B oil port of the first one-way valve 7 is respectively connected to the A oil port of the first filter screen 12 and the A oil port of the relief valve 11; the B oil port of the first filter screen 12 is respectively connected to the first temperature and pressure integrated sensor 15 and the P1 oil port of the two-position six-way hydraulically controlled directional valve 4 with an in-built displacement sensor; the B oil port of the relief valve 11 is respectively connected to the T1 oil port of the two-position six-way hydraulically controlled directional valve 4 with an in-built displacement sensor, the A oil port of the second filter screen 13 and the A oil port of the bypass valve 14; the B oil port of the second filter screen 13 is respectively connected to the B oil port of the bypass valve 14 and the A oil port of the fourth one-way valve 10; the B oil port of the fourth one-way valve 10 is connected to the main system oil return port; the P2 oil port of the two-position six-way hydraulically controlled directional valve 4 with an in-built displacement sensor is respectively connected to the second temperature and pressure integrated sensor 16, the P oil port of the first normally closed two-position three-way solenoid valve 1 and the standby system oil inlet; the T2 oil port of the two-position six-way hydraulically controlled directional valve 4 with an in-built displacement sensor is respectively connected to the R oil port of the first normally closed two-position three-way solenoid valve 1 and the standby system oil return port; the A oil port of the two-position six-way hydraulically controlled directional valve 4 with an in-built displacement sensor is respectively connected to the P oil port of the second normally closed two-position three-way solenoid valve 2, the A oil port of the first normally open two-position three-way hydraulically controlled directional valve 5, the P oil port of the third normally closed two-position three-way solenoid valve 3 and the A oil port of the second normally open two-position three-way hydraulically controlled directional valve 6; the B oil port of the two-position six-way hydraulically controlled directional valve 4 with an in-built displacement sensor is respectively connected to the B oil port of the second one-way valve 8 and the B oil port of the third one-way valve 9; the X hydraulic control port of the two-position six-way hydraulically controlled directional valve 4 with an in-built displacement sensor is connected to the C control oil port of the first normally closed two-position three-way solenoid valve 1; the B oil port of the first normally open two-position three-way hydraulically controlled directional valve 5 is respectively connected to the first pressure sensor 17 and the oil inlet of the main propeller rudder machine; the T oil port of the first normally open two-position three-way hydraulically controlled directional valve 5 is respectively connected to the oil return port of the main propeller rudder machine, the R oil port of the second normally closed two-position three-way solenoid valve 2 and the A oil port of the second one-way valve 8; the X hydraulic control port of the first normally open two-position three-way hydraulically controlled directional valve 5 is connected to the C control oil port of the second normally closed two-position three-way solenoid valve 2; the B oil port of the second normally open two-position three-way hydraulically controlled directional valve 6 is respectively connected to the second pressure sensor 18 and the oil inlet of the tail rotor rudder machine; the T oil port of the second normally open two-position three-way hydraulically controlled directional valve 6 is respectively connected to the oil return port of the tail rotor rudder machine, the R oil port of the third normally closed two-position three-way solenoid valve 3 and the A oil port of the third one-way valve 9; the X hydraulic control port of the second normally open two-position three-way hydraulically controlled directional valve 6 is connected to the C control oil port of the third normally closed two-position three-way solenoid valve 3.

[0104] When the first normally-closed two-position three-way solenoid valve 1 is not powered on, the P oil port of the first normally-closed two-position three-way solenoid valve 1 is in a closed state, and the C control oil port and the R oil port are connected. At this time, since the X hydraulic control port of the two-position six-way hydraulic control directional valve 4 with an in-built displacement sensor is directly connected to the return oil port of the standby system, under the biasing action of the spring force, the two-position six-way hydraulic control directional valve 4 with an in-built displacement sensor is in the right position, the P1 oil port is connected to the A oil port, the T1 oil port is connected to the B oil port, and the P2 oil port and the T2 oil port are closed, and the system is in the main system oil supply state. When the first normally-closed two-position three-way solenoid valve 1 is powered on, the P oil port of the first normally-closed two-position three-way solenoid valve 1 is connected to the C control oil port, and the R oil port is in a closed state. At this time, since the inlet oil port of the standby system is directly connected to the X hydraulic control port of the two-position six-way hydraulic control directional valve 4 with an in-built displacement sensor, under the high pressure of the standby hydraulic system, the two-position six-way hydraulic control directional valve 4 with an in-built displacement sensor switches to the left position, the P2 oil port is connected to the A oil port, the T2 oil port is connected to the B oil port, and the P1 oil port and the T1 oil port are closed, and the system is in the standby system oil supply state.

[0105] When the second normally-closed two-position three-way solenoid valve 2 is not powered on, the P oil port of the second normally-closed two-position three-way solenoid valve 2 is in a closed state, and the C oil port and the R oil port are connected. At this time, since the X hydraulic control port of the first normally-open two-position three-way hydraulic control directional valve 5 is connected to the low-pressure return oil circuit of the system, under the biasing action of the spring force, the first normally-open two-position three-way hydraulic control directional valve 5 is in the right position, the A oil port is connected to the B oil port, and the T oil port is closed, and the system supplies oil to the main propeller rudder oil circuit normally. When the second normally-closed two-position three-way solenoid valve 2 is powered on, the P oil port of the second normally-closed two-position three-way solenoid valve 2 is connected to the C control oil port, and the R oil port is in a closed state. At this time, since the X hydraulic control port of the first normally-open two-position three-way hydraulic control directional valve 5 is connected to the high-pressure inlet oil circuit of the system, the first normally-open two-position three-way hydraulic control directional valve 5 switches to the left position, the A oil port is closed, and the B oil port is connected to the T oil port, and the system stops supplying oil to the main propeller rudder oil circuit.

[0106] Similarly, when the third normally-closed two-position three-way solenoid valve 3 is not powered on, the P oil port of the third normally-closed two-position three-way solenoid valve 3 is in a closed state, and the C oil port and the R oil port are connected. At this time, since the X hydraulic control port of the second normally-open two-position three-way hydraulic control directional valve 6 is connected to the low-pressure return oil circuit of the system, under the biasing action of the spring force, the second normally-open two-position three-way hydraulic control directional valve 6 is in the right position, the A oil port is connected to the B oil port, and the T oil port is closed, and the system supplies oil to the tail propeller rudder oil circuit normally. When the third normally-closed two-position three-way solenoid valve 3 is powered on, the P oil port of the third normally-closed two-position three-way solenoid valve 3 is connected to the C control oil port, and the R oil port is in a closed state. At this time, since the X hydraulic control port of the second normally-open two-position three-way hydraulic control directional valve 6 is connected to the high-pressure inlet oil circuit of the system, the second normally-open two-position three-way hydraulic control directional valve 6 switches to the left position, the A oil port is closed, and the B oil port is connected to the T oil port, and the system stops supplying oil to the tail propeller rudder oil circuit.

[0107] Under normal circumstances, the first normally closed two-position three-way solenoid valve 1, the second normally closed two-position three-way solenoid valve 2, and the third normally closed two-position three-way solenoid valve 3 are all in the power-off state, that is, the two-position six-way hydraulic control reversing valve 4 with an internal displacement sensor, the first normally open two-position three-way hydraulic control solenoid valve 5, and the second normally open two-position three-way hydraulic control solenoid valve 6 are all in the right position. At this time, the main rotor servo and the tail rotor servo are in the normal oil supply state of the main system. When faults such as sudden changes in the main system pressure, different degrees of pressure loss or even complete pressure loss in the main system, oil leakage in the main rotor servo oil circuit, pressure loss due to rupture of the main rotor servo oil circuit, oil leakage in the tail rotor servo oil circuit, and pressure loss due to rupture of the tail rotor servo oil circuit occur, the intelligent combined valve group of the helicopter hydraulic system makes a comprehensive decision based on the pressure signals of the four oil circuits collected by the first temperature and pressure integrated sensor 15, the second temperature and pressure integrated sensor 16, the first pressure sensor 17, and the second pressure sensor 18, determines the energization status of the three solenoid valves, and finally realizes the pressure switching between the main and standby systems or the cut-off of the servo oil circuit.

[0108] In this embodiment, the working principle of the intelligent combined valve group of the helicopter hydraulic system is specifically as follows:

[0109] A first check valve 7 is provided on the main system oil supply return circuit of the combined valve group of the helicopter hydraulic system to prevent oil from flowing back and damaging the main system oil source equipment; the oil supplied by the main system flows through the first check valve 7 and then to the first filter screen 12. The first filter screen 12 filters impurities in the oil to ensure the cleanliness of the oil; at the same time, a relief valve 11 is also provided behind the first check valve 7 for overpressure protection of the main system. A first temperature and pressure integrated sensor 15 is provided on the oil circuit from the first filter screen 12 to the two-position six-way hydraulic control reversing valve 4 with an internal displacement sensor, which is used to simultaneously monitor the pressure and temperature signals of the main system oil circuit.

[0110] A first normally closed two-position three-way solenoid valve 1 is provided on the standby system oil supply return circuit of the combined valve group. The control oil port of this solenoid valve is connected to the hydraulic control port of the two-position six-way hydraulic control reversing valve 4 with an internal displacement sensor. When the solenoid valve is energized, the high-pressure oil of the standby system enters the hydraulic control port of the two-position six-way hydraulic control reversing valve 4 with an internal displacement sensor for pressure switching between the main and standby systems. In addition, a second temperature and pressure integrated sensor 16 is provided on the oil circuit from the standby system oil supply return circuit of the combined valve group to the two-position six-way hydraulic control reversing valve 4 with an internal displacement sensor, which is used to simultaneously monitor the pressure and temperature signals of the standby system oil circuit.

[0111] Due to the action of the biasing spring, the two-position six-way hydraulically controlled directional valve 4 with an in-built displacement sensor defaults to the right position. At this time, the system is supplied with oil by the main system. When the pressure of the main and standby systems is switched, the two-position six-way hydraulically controlled directional valve 4 with an in-built displacement sensor switches to the left position and switches to supplying oil from the standby system. The form of the in-built displacement sensor can monitor the position of the main spool for pressure switching in real time. The oil outlet of the two-position six-way hydraulically controlled directional valve 4 with an in-built displacement sensor is connected to the second normally closed two-position three-way solenoid valve 2, the third normally closed two-position three-way solenoid valve 3, the first normally open two-position three-way hydraulically controlled directional valve 5, and the second normally open two-position three-way hydraulically controlled directional valve 6 at the same time.

[0112] The second normally closed two-position three-way solenoid valve 2 is the cut-off control valve for the main propeller rudder oil circuit, and its control oil port is connected to the hydraulic control port of the first normally open two-position three-way hydraulically controlled directional valve 5. When the second normally closed two-position three-way solenoid valve 2 is energized, it will push the first normally open two-position three-way hydraulically controlled directional valve 5 to switch to the left position, cutting off the main propeller rudder oil circuit. Similarly, the third normally closed two-position three-way solenoid valve 3 is the cut-off control valve for the tail propeller rudder oil circuit, and its control oil port is connected to the hydraulic control port of the second normally open two-position three-way hydraulically controlled directional valve 6. When the third normally closed two-position three-way solenoid valve 3 is energized, it will push the second normally open two-position three-way hydraulically controlled directional valve 6 to switch to the left position, cutting off the tail propeller rudder oil circuit.

[0113] A first pressure sensor 17 is provided on the oil outlet oil path of the first normally open two-position three-way hydraulically controlled directional valve 5 for monitoring the pressure signal of the main propeller rudder oil circuit. A second pressure sensor 18 is provided on the oil outlet oil path of the second normally open two-position three-way hydraulically controlled directional valve 6 for monitoring the pressure signal of the tail propeller rudder oil circuit.

[0114] The return oil of the main propeller rudder and the tail propeller rudder will respectively return to the oil return port of the two-position six-way hydraulically controlled directional valve 4 with an in-built displacement sensor through the second one-way valve 8 and the third one-way valve 9. After the return oil of the two load oil circuits merges, it flows to the second filter screen 13 together with the oil from the outlet of the relief valve 11 to filter impurities in the oil, ensuring the cleanliness of the oil. When the pressure difference before and after the second filter screen 13 is greater than the set value, the bypass valve 14 will be opened to avoid pressure buildup in the return oil pipeline; the fourth one-way valve 10 is after the second filter screen 13 to prevent the oil in the main system hydraulic oil tank from flowing back.

[0115] In this embodiment, the test result diagram of the working principle of the intelligent combined valve group of the helicopter hydraulic system under various fault forms is as Figure 3 shown. It should be noted that Figure 3 the test situations presented in

[0116] are only a part of many test scenarios, aiming to reflect the working state and performance of the valve group under specific typical fault forms, and do not cover all the functions of the valve group. Figure 3It can be seen that after adding a displacement sensor and a load rudder oil circuit pressure sensor, the visualization degree of the main / standby system pressure switching state and the load cut-off state of the intelligent combined valve group of the helicopter hydraulic system has been significantly improved, and the intuitive judgment can be directly made through the spool displacement signal and the main and tail rotor rudder oil circuit pressure signals. When the valve group is dealing with various fault conditions (including pressure mutations of different amplitudes in the main system, complete loss of pressure in the main system, fluctuations near the preset pressure loss threshold and then recovery after the main system loses pressure, rupture and pressure loss in the main rotor servo hydraulic circuit, rupture and pressure loss in the tail rotor servo hydraulic circuit, etc.), it can accurately perform system switching and load cut-off operations. Its remarkable feature is that it will not directly switch due to a sharp drop in pressure, resulting in leakage affecting the standby system oil source, nor will it cause frequent redundant switching due to instantaneous disturbances at the load end, reflecting the stability of anti-interference switching. When a rupture and pressure loss fault occurs in the load oil circuit, the valve group has a fast response ability, can promptly cut off the faulty oil circuit, and at the same time ensure that the unaffected oil circuit maintains a normal operating state.

[0117] The above specific embodiments are used to explain and illustrate the present invention, rather than limiting the present invention. Any modification and change made to the present invention within the spirit and scope of the claims of the present invention fall within the protection scope of the present invention.

Claims

1. An intelligent combined valve group for a helicopter hydraulic system, characterized in that, Including: A two-position six-way hydraulic control reversing valve (4), the P1 oil port and the T1 oil port are respectively connected to the main system oil inlet and the return oil port to form the main system oil circuit, and the P2 oil port and the T2 oil port are respectively connected to the standby system oil inlet and the return oil port to form the standby system oil circuit; A first normally open two-position three-way hydraulic control reversing valve (5), the A oil port and the B oil port are respectively connected to the A oil port of the two-position six-way hydraulic control reversing valve (4) and the oil inlet of the main propeller rudder machine, and the T oil port is respectively connected to the return oil port of the main propeller rudder machine and the B oil port of the two-position six-way hydraulic control reversing valve (4) to form the main propeller rudder machine oil circuit; A second normally open two-position three-way hydraulic control reversing valve (6), the A oil port and the B oil port are respectively connected to the A oil port of the two-position six-way hydraulic control reversing valve (4) and the oil inlet of the tail propeller rudder machine, and the T oil port is respectively connected to the return oil port of the tail propeller rudder machine and the B oil port of the two-position six-way hydraulic control reversing valve (4) to form the tail propeller rudder machine oil circuit; Three normally closed two-position three-way solenoid valves, which are respectively used to control the two-position six-way hydraulic control reversing valve (4), the first normally open two-position three-way hydraulic control reversing valve (5) and the second normally open two-position three-way hydraulic control reversing valve (6); A sensor module, including two temperature and pressure integrated sensors, which are respectively used to monitor the temperature and pressure signals of the main system and the standby system oil circuits, two pressure sensors, which are respectively used to monitor the pressure signals of the main propeller rudder machine oil circuit and the tail propeller rudder machine oil circuit, and a displacement sensor, which is built in the two-position six-way hydraulic control reversing valve (4) and is used to monitor the spool position.

2. The intelligent combined valve group of the helicopter hydraulic system according to claim 1, wherein: For the first normally open two-position three-way hydraulic control reversing valve (5) and the second normally open two-position three-way hydraulic control reversing valve (6), in the working state, the A oil port is connected to the B oil port and the T oil port is closed; in the off state, the A oil port is closed and the B oil port is connected to the T oil port; for the two-position six-way hydraulic control reversing valve (4), in the working state, the P1 oil port is connected to the A oil port, the T1 oil port is connected to the B oil port, and the P2 oil port and the T2 oil port are closed; in the off state, the P2 oil port is connected to the A oil port, the T2 oil port is connected to the B oil port, and the P1 oil port and the T1 oil port are closed.

3. The intelligent combined valve group of the helicopter hydraulic system according to claim 1 or 2, characterized in that: The three normally closed two-position three-way solenoid valves are respectively the first normally closed two-position three-way solenoid valve (1), the second normally closed two-position three-way solenoid valve (2) and the third normally closed two-position three-way solenoid valve (3); the first normally closed two-position three-way solenoid valve (1) is used to control the X hydraulic control port of the two-position six-way hydraulic control reversing valve (4), and the C control oil port is connected to the X hydraulic control port of the two-position six-way hydraulic control reversing valve (4); the second normally closed two-position three-way solenoid valve (2) is used to control the X hydraulic control port of the first normally open two-position three-way hydraulic control reversing valve (5), and the C control oil port is connected to the X hydraulic control port of the first normally open two-position three-way hydraulic control reversing valve (5); the third normally closed two-position three-way solenoid valve (3) is used to control the X hydraulic control port of the second normally open two-position three-way hydraulic control reversing valve (6), and the C control oil port is connected to the X hydraulic control port of the second normally open two-position three-way hydraulic control reversing valve (6); after each normally closed two-position three-way solenoid valve is energized, the C control oil port is connected to the P oil port, and the connected hydraulic control reversing valve is switched to the off state.

4. The intelligent combined valve group of the helicopter hydraulic system according to claim 1, characterized in that: The valve group further includes a control unit, which is used to control the on-off of three normally-closed two-position three-way solenoid valves according to the real-time signals collected by two temperature and pressure integrated sensors and two pressure sensors; the control unit is electrically connected to the three normally-closed two-position three-way solenoid valves respectively, and is communicatively connected to the two temperature and pressure integrated sensors and the two pressure sensors respectively.

5. The intelligent combined valve group of the helicopter hydraulic system according to claim 1, characterized in that: The two temperature and pressure integrated sensors are respectively the first temperature and pressure integrated sensor (15) and the second temperature and pressure integrated sensor (16) arranged between the two-position six-way hydraulic control reversing valve (4) and the main system oil inlet, and between the two-position six-way hydraulic control reversing valve (4) and the standby system oil inlet; the two pressure sensors are respectively the first pressure sensor (17) and the second pressure sensor (18) arranged between the first normally-open two-position three-way hydraulic control reversing valve (5) and the oil inlet of the main propeller rudder machine, and between the second normally-open two-position three-way hydraulic control reversing valve (6) and the oil inlet of the tail propeller rudder machine.

6. The intelligent combined valve group of the helicopter hydraulic system according to claim 1, wherein: The valve group further includes a first check valve (7), a fourth check valve (10), a relief valve (11), a first filter screen (12), a second filter screen (13) and a bypass valve (14); On the main system oil inlet oil path between the main system oil inlet and the P1 oil port of the two-position six-way hydraulic control reversing valve (4), a first check valve (7), a first filter screen (12) and a first temperature and pressure integrated sensor (15) are arranged in sequence; on the main system oil return oil path between the main system oil return port and the T1 oil port of the two-position six-way hydraulic control reversing valve (4), a second filter screen (13) and a fourth check valve (10) are arranged in sequence, and the second filter screen (13) is connected in parallel with the bypass valve (14); A relief valve (11) is arranged between the main system oil inlet and return oil paths. The inlet end of the relief valve (11) is arranged between the first check valve (7) and the first filter screen (12), and the outlet end is arranged between the T1 oil port of the two-position six-way hydraulic control reversing valve (4) and the second filter screen (13).

7. The intelligent combined valve group of the helicopter hydraulic system according to claim 1, characterized in that: The valve group further includes a second check valve (8) and a third check valve (9); the A oil port of the second check valve (8) is respectively communicated with the T oil port of the first normally-open two-position three-way hydraulic control reversing valve (5) and the oil return port of the main propeller rudder machine, and the B oil port is communicated with the B oil port of the two-position six-way hydraulic control reversing valve (4); the A oil port of the third check valve (9) is respectively communicated with the T oil port of the second normally-open two-position three-way hydraulic control reversing valve (6) and the oil return port of the tail propeller rudder machine, and the B oil port is communicated with the B oil port of the two-position six-way hydraulic control reversing valve (4).

8. A control method for an intelligent combined valve group of a helicopter hydraulic system as described in any one of claims 1 to 7, characterized in that, It includes the following steps: The first step, open circuit detection: detect whether the pressure signal of the first temperature and pressure integrated sensor (15) is greater than zero; If it is greater than zero, set the pressure switching decision value as the pressure signal of the first temperature and pressure integrated sensor (15); otherwise, take the larger value of the pressure signals of the first pressure sensor (17) and the second pressure sensor (18) plus a preset compensation value as the pressure switching decision value; The second step, forced cut-off detection: judge whether the pressure switching decision value is higher than a preset forced cut-off threshold. If it is higher than the forced cut-off threshold, execute the third step; Otherwise, execute the sixth step; Step 3, pressure loss detection: Determine whether the pressure switching decision value is lower than the preset pressure loss switching threshold. If it is lower than the pressure loss switching threshold, execute Step 4; otherwise, execute Step 10; Step 4, pressure mutation detection: Start the pressure loss discrimination delay. After the delay ends, update the pressure switching decision value according to the real-time pressure signal, and determine again whether the pressure switching decision value is lower than the preset pressure loss switching threshold. If it is lower than the pressure loss switching threshold, execute Step 5; otherwise, execute Step 10; Step 5, determine whether the pressure switching decision value is lower than the preset first leakage cut-off threshold. If it is lower than the first leakage cut-off threshold, execute Step 6; otherwise, execute Step 14; Step 6, energize the second normally closed two-way three-way solenoid valve (2). After energization, delay, update the pressure switching decision value according to the real-time pressure signal, and determine whether the pressure switching decision value is lower than the first leakage cut-off threshold. If it is lower than the first leakage cut-off threshold, give the status alarm "main system pressure loss", execute Step 7; otherwise, give the status alarm "main propeller and rudder oil circuit rupture and pressure loss", execute Step 14; Step 7, energize the first normally closed two-way three-way solenoid valve (1), de-energize the second normally closed two-way three-way solenoid valve (2), and delay after de-energization; Step 8, update the pressure switching decision value according to the real-time pressure signal, and determine whether the pressure switching decision value is higher than the preset recovery pressure threshold. If it is lower than the recovery pressure threshold, the system is in the standby system oil supply state, maintain the status alarm "main system pressure loss", the valve group continuously monitors the main system pressure, and re-enter Step 8; otherwise, cancel the status alarm "main system pressure loss", execute Step 9; Step 9, de-energize the first normally closed two-way three-way solenoid valve (1), and return to Step 1; Step 10, small leakage detection: Detect whether the hydraulic oil level of the main system is as low as the first oil level control value. If it is lower than the first oil level control value, give the status alarm "oil circuit leakage", execute Step 11; otherwise, return to Step 1; Step 11, energize the third normally closed two-way three-way solenoid valve (3), and delay after energization; Step 12, detect whether the hydraulic oil level of the main system is as low as the second oil level control value. If it is lower than the second oil level control value, give the status alarm "continuous oil circuit leakage", execute Step 13; Otherwise, re-enter Step 12; Step 13, energize the second normally closed two-way three-way solenoid valve (2), and the process ends; Step 14, determine whether the pressure switching decision value is lower than the second leakage cut-off threshold. If it is lower than the second leakage cut-off threshold, execute Step 15; otherwise, execute Step 10; Step 15, energize the third normally closed two-way three-way solenoid valve (3), delay after energization, update the pressure switching decision value according to the real-time pressure signal, and determine whether the pressure switching decision value is lower than the second leakage cut-off threshold. If it is lower than the second leakage cut-off threshold, give the status alarm "main system pressure loss", execute Step 16; otherwise, give the status alarm "tail propeller and rudder oil circuit rupture and pressure loss", execute Step 10; Step 16, energize the first normally closed two-way three-way solenoid valve (1), de-energize the second normally closed two-way three-way solenoid valve 2 and the third normally closed two-way three-way solenoid valve (3), delay after de-energization, and execute Step 8.

9. The control method according to claim 8, wherein: The thresholds are as follows from low to high: forced cut-off threshold, first leakage cut-off threshold, second leakage cut-off threshold, pressure loss switching threshold, recovery pressure threshold, and rated working pressure.

10. The control method according to claim 8, characterized in that: In steps 6, 7, 9, 11, 13, 15 and 16, after any normally closed two-position three-way solenoid valve is energized or de-energized, a time delay is maintained until the corresponding hydraulically controlled reversing valve completes reversing before proceeding to the next step.

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