Brake servo valve prestage pressure gain compensation device

Abstract

The utility model discloses a brake servo valve prestage pressure gain compensation device, and relates to the technical field of aviation hydraulic brake systems. The device is located in a brake servo valve shell and arranged between a jet amplifier and a main valve element and comprises a pilot valve element, an adjusting spring and a feedback assembly, the adjusting spring is connected to the side portion of the pilot valve element, and the feedback assembly is used for connecting the pilot valve element with a torque motor of the brake servo valve. When the control pressure of the jet amplifier acts on the main valve core and the pilot valve core, the pilot valve core generates displacement under the action of the control pressure, and the adjusting spring is compressed in the process until the spring force generated by the compression of the adjusting spring is balanced with the hydraulic force; and then the feedback assembly feeds the displacement of the pilot valve element back to the torque motor, negative feedback control over the torque motor and prestage pressure gain is formed, the control pressure of the jet amplifier is compensated, and the brake pressure stability of the brake servo valve is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to aviation hydraulic brake system technical field, concretely relates to a brake servo valve prestage pressure gain compensation device. BACKGROUND

[0002] The aircraft brake system is an important component of the aircraft on-board equipment, which provides friction resistance for the aircraft wheels, and realizes safe, reliable and rapid braking and control during take-off, landing, taxiing and turning of the aircraft, and the performance directly affects the rapid response, safe return and sustained combat capability of the aircraft, and further affects the overall performance of the aircraft.

[0003] The aircraft hydraulic brake system at home and abroad widely uses brake servo valves to control the wheel brake pressure. The brake servo valve connects the electrical part with the hydraulic part, and serves as a signal conversion element and a power amplification element. The main function is to receive the electrical command signal sent by the system, and convert the electrical signal into a signal with corresponding polarity, proportion and brake pressure control capability, so that the system outputs larger hydraulic power and brake pressure proportional to the control current, controls the brake friction torque of the brake system, and shortens the braking distance after landing. Generally, each brake servo valve controls the brake pressure of one or several wheels. Once the brake servo valve fails, it will cause the wheel brake to slip or lock, and even cause serious accidents such as tire burst, which endangers the flight safety.

[0004] The control principle diagram of the traditional brake servo valve is shown in Figure 1 , the control current input torque motor outputs torque acting on the nozzle, the nozzle produces displacement, deflects to the jet amplifier to generate control pressure, which acts on the main valve core to make the main valve core act to output pressure. At the same time, the output pressure and the oil return pressure feedback on the main valve core to adjust the displacement of the main valve core, and finally reach dynamic balance.

[0005] The traditional brake servo valve has the characteristics that only the main valve core has pressure feedback function, the output brake pressure and the received jet amplifier control pressure form a closed loop control, while the jet amplifier control pressure of the prestage is in an open loop state without closed loop feedback control, which is more susceptible to changes in external environment, resulting in changes in control pressure, and ultimately leading to output brake pressure exceeding the requirements and not meeting the technical requirements. According to the historical failure data of the brake servo valve, the output brake pressure not meeting the technical requirements is one of the main failure modes, accounting for about 50%. Therefore, the present application provides a brake servo valve prestage pressure gain compensation device. CONTENT OF THE UTILITY MODEL

[0006] The utility model mainly aims at providing a brake servo valve prestage pressure gain compensation device to overcome the problems in the prior art.

[0007] To solve the above technical problems, the utility model adopts the following technical scheme:

[0008] A brake servo valve pre-stage pressure gain compensation device, the device is located in the shell of brake servo valve, and is arranged between the jet amplifier and the main valve spool, the device includes a pilot spool, an adjusting spring and a feedback assembly, the adjusting spring is connected to the side of the pilot spool, and the feedback assembly is used for connecting the pilot spool and the torque motor of brake servo valve.

[0009] Further, the number of the adjusting spring is two, and the two adjusting springs are respectively located on the two sides of the pilot spool.

[0010] Further, the jet amplifier is composed of a jet pipe, a nozzle and a receptor.

[0011] Further, when the control pressure of the jet amplifier acts on the main valve spool, the control pressure also acts on the pilot spool, the pilot spool generates displacement under the action of the control pressure, in the process, the adjusting spring is compressed, until the spring force generated by the compression of the adjusting spring and the hydraulic pressure are balanced, then the feedback assembly feeds back the displacement of the pilot spool to the torque motor, forms negative feedback control to the torque motor and the pre-stage pressure gain, and compensates the control pressure of the jet amplifier.

[0012] Further, when the oil supply pressure rises, the control pressure of the jet amplifier becomes larger, at this time, the feedback position of the pilot spool is rightward compared with the original position, the spring force of the adjusting spring on the left side becomes smaller, and the spring force of the adjusting spring on the right side becomes larger, so that a leftward thrust is generated to the pilot spool, the pilot spool moves leftward, after the pilot spool moves leftward, the nozzle is driven to move rightward through the feedback assembly, so that the pressure on the left side of the receptor becomes smaller, and the pressure on the right side becomes larger, the control pressure of the jet amplifier is reduced, pressure gain compensation is formed, and the change of brake pressure is reduced.

[0013] Compared with the prior art, the utility model has the following beneficial effects:

[0014] The utility model increases pre-stage pressure gain compensation device on the basis of traditional brake servo valve, realizes closed loop control to jet amplifier control pressure through pressure gain compensation, reduces the influence of external environment change, improves the brake pressure stability of brake servo valve, solves the problem that brake servo valve output brake pressure is out of tolerance, and improves the reliability of aircraft hydraulic brake system. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is the control principle diagram of traditional brake servo valve.

[0016] Figure 2 It is the control principle diagram of the brake servo valve after increasing the pre-stage pressure gain compensation device.

[0017] Figure 3 It is the control principle diagram of the brake servo valve after increasing the pre-stage pressure gain compensation device.

[0018] Figure 4 It is the front view of the brake servo valve.

[0019] Figure 5 It is the side view of the brake servo valve.

[0020] Among them, 1 is a pre-stage pressure gain compensation device, 2 is a pilot valve core, 3 is an adjusting spring, and 4 is a feedback assembly. DETAILED DESCRIPTION

[0021] The technical scheme of the utility model is further described below by means of drawings and examples.

[0022] In combination Figures 2 to 5 The embodiment provides a brake servo valve pre-stage pressure gain compensation device, which is applied to a brake servo valve of an aviation hydraulic brake system and is used for solving the problem of brake servo valve output brake pressure out-of-tolerance and improving the reliability of an airplane brake system.

[0023] The device is located in the shell of the brake servo valve and is arranged between a jet amplifier and a main valve core, the device comprises a pilot valve core 2, an adjusting spring 3 and a feedback assembly 4, the adjusting spring 3 is connected to the side of the pilot valve core 2, and the feedback assembly 4 is used for connecting the pilot valve core 2 and a torque motor of the brake servo valve.

[0024] When the control pressure of the jet amplifier acts on the main valve core, the control pressure also acts on the pilot valve core 2, the pilot valve core 2 generates displacement under the action of the control pressure, in the process, the adjusting spring 3 is compressed, until the spring force generated by the compression of the adjusting spring 3 and the hydraulic pressure are balanced, then the feedback assembly 4 feeds back the displacement of the pilot valve core 2 to the torque motor, negative feedback control of the torque motor and the pre-stage pressure gain is formed, and the control pressure of the jet amplifier is compensated.

[0025] In the embodiment, the number of adjusting springs 3 is two, and the two adjusting springs 3 are located on the two sides of the pilot valve core 2.

[0026] In the embodiment, the jet amplifier is composed of a jet pipe, a nozzle and a receptor.

[0027] In the embodiment, the pre-stage pressure gain compensation device 1 compensates the zero offset and zero drift caused by changes in system oil supply pressure, oil return pressure, oil temperature and the like.

[0028] Taking the change in system oil supply pressure as an example, for a conventional brake servo valve, after the change in oil supply pressure, the jet amplifier control pressure changes proportionally, the brake pressure changes proportionally, and the change range is large.

[0029] After the pre-stage pressure gain compensation device 1 is added, the pre-stage jet amplifier control pressure acts on the pilot valve spool 2 in addition to acting on the main valve spool, so that the pilot valve spool 2 generates a displacement, until the spring force and the hydraulic pressure generated by the displacement of the valve spool are balanced. The displacement of the pilot valve spool 2 is fed back to the torque motor through the feedback assembly 4 connected to the pilot valve spool 2 and the torque motor, forming a negative feedback control on the torque motor and the pre-stage pressure gain, compensating the jet amplifier control pressure, and improving the brake pressure stability of the brake servo valve.

[0030] When the oil supply pressure rises, the control pressure of the pre-stage jet amplifier becomes larger, the feedback position of the pilot valve spool 2 moves right compared to the original position, the spring force of the left adjusting spring 3 becomes smaller, and the spring force of the right adjusting spring 3 becomes larger, generating a leftward thrust on the pilot valve spool 2, so that the pilot valve spool 2 moves left. After the pilot valve spool 2 moves left, the nozzle is driven to move right through the feedback assembly 4, so that the pressure on the left side of the receiver becomes smaller, and the pressure on the right side becomes larger, reducing the control pressure of the jet amplifier, forming pressure gain compensation, and making the change in brake pressure smaller.

[0031] According to the test data, when the system oil supply pressure changes by 1 MPa, the brake pressure of the conventional brake servo valve changes by 0.8 MPa. When the system oil supply pressure changes by 1 MPa, the brake pressure output by the brake servo valve with the pre-stage pressure gain compensation device 1 added changes by only 0.2 MPa, and the improvement effect is significant. Therefore, after the pre-stage pressure gain compensation device 1 is added to the conventional brake servo valve, the jet amplifier control pressure is closed-loop controlled through pressure gain compensation, the influence of external environmental changes is reduced, the brake pressure stability of the brake servo valve is improved, the problem of brake pressure output by the brake servo valve being out of tolerance is solved, and the reliability of the aircraft hydraulic brake system is improved.

[0032] The above is only a preferred embodiment of the present application, and does not limit the technical scope of the present application in any way. Therefore, any slight modification, equivalent change and modification made according to the technical essence of the present application to the above embodiment still falls within the scope of the technical solution of the present application.

Claims

1. A brake servo valve pre-stage pressure gain compensation device characterized by, The device is located inside the housing of the brake servo valve, and is arranged between the fluid amplifier and the main valve spool, the device comprises a pilot valve spool, adjusting springs and a feedback assembly, the adjusting springs are connected to the side of the pilot valve spool, and the feedback assembly is used for connecting the pilot valve spool and the torque motor of the brake servo valve. The front-stage pressure gain compensation device is used for compensating the zero offset and zero drift caused by changes of system oil supply pressure, oil return pressure and oil temperature.

2. A brake servo valve pre-stage pressure gain compensation device as claimed in claim 1, characterized in that The number of the adjusting springs is two, and the two adjusting springs are respectively arranged on the two sides of the pilot valve spool.

3. A brake servo valve pre-stage pressure gain compensation device as claimed in claim 1, wherein The fluid amplifier is composed of a fluid amplifier pipe, a nozzle and a receiver.

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