Brake servo valve prestage pressure gain compensation device

Abstract

The invention 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 shell of the brake servo valve 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 element and the pilot valve element at the same time, the pilot valve element generates displacement under the action of the control pressure, and the adjusting spring is compressed in the process until the spring force generated when the adjusting spring is compressed 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, compensation is conducted on the control pressure of the jet amplifier, and the brake pressure stability of the brake servo valve is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of aviation hydraulic brake systems, and in particular to a brake servo valve pre-stage pressure gain compensation device. Background Art

[0002] The aircraft braking system is an important component of the aircraft's onboard equipment. Its function is to provide friction resistance to the aircraft's wheels, and to safely, reliably and quickly achieve braking and control during aircraft takeoff, landing, taxiing and turning. Its performance directly affects the aircraft's rapid response, safe return and sustained combat capabilities, and thus affects the aircraft's overall performance.

[0003] Brake servo valves are widely used in hydraulic brake systems of domestic and foreign aircraft to control wheel brake pressure. Brake servo valves connect the electrical part with the hydraulic part, and serve as both a signal conversion element and a power amplifier element. Their main function is to receive the electrical command signal sent by the system and convert the electrical signal into a proportional signal with corresponding polarity that can control the brake pressure, so that the system can output a larger hydraulic power and output a brake pressure proportional to the control current, control the brake friction torque of the brake system, and shorten the braking distance of the aircraft 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 in severe cases, it may cause serious accidents such as tire blowouts, endangering flight safety.

[0004] The control principle diagram of the traditional brake servo valve is shown in Figure 1 After the control current is input into the torque motor, the output torque acts on the nozzle, the nozzle is displaced, and deflected to the jet amplifier to generate control pressure, which acts on the main valve core to cause the main valve core to move and output pressure. At the same time, the output pressure and return oil pressure are fed back to the main valve core to adjust the displacement of the main valve core and finally achieve dynamic balance.

[0005] The characteristic of the traditional brake servo valve is that only the main valve core has the pressure feedback function, which forms a closed-loop control between the output brake pressure and the received jet amplifier control pressure, while the pre-stage jet amplifier control pressure is in an open-loop state, without closed-loop feedback regulation and control, and is more susceptible to changes in the external environment, resulting in changes in the control pressure, and ultimately causing the output brake pressure to exceed the tolerance and fail to meet the technical requirements. According to the statistics of the brake servo valve's failure data over the years, the output brake pressure not meeting the technical requirements is one of the main failure modes, accounting for about 50%. Therefore, this patent proposes a brake servo valve pre-stage pressure gain compensation device. Summary of the invention

[0006] The main purpose of the present invention is to provide a brake servo valve pre-stage pressure gain compensation device to overcome the problems existing in the prior art.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A brake servo valve pre-stage pressure gain compensation device, the device is located inside the housing of the brake servo valve and is arranged between the jet amplifier and the main valve core, the device includes a pilot valve core, an adjustment spring and a feedback component, the adjustment spring is connected to the side of the pilot valve core, and the feedback component is used to connect the pilot valve core and the torque motor of the brake servo valve;

[0009] When the control pressure of the jet amplifier acts on the main valve core, it also acts on the pilot valve core. The pilot valve core is displaced under the control pressure. During this process, the adjusting spring is compressed until the spring force and liquid pressure generated by the compression of the adjusting spring are balanced. Then, the feedback component feeds back the displacement of the pilot valve core to the torque motor, forming a negative feedback control of the torque motor and the pre-stage pressure gain, thereby compensating the control pressure of the jet amplifier.

[0010] Furthermore, the number of the regulating springs is two, and the two regulating springs are respectively located on both sides of the pilot valve core.

[0011] Furthermore, the jet amplifier is composed of a jet tube, a nozzle and a receiver.

[0012] Furthermore, when the oil supply pressure increases, the control pressure of the jet amplifier increases. At this time, the feedback position of the pilot valve core moves to the right compared to the original position, the spring force of the adjusting spring on the left side decreases, and the spring force of the adjusting spring on the right side increases, thereby generating a leftward thrust on the pilot valve core, causing the pilot valve core to move to the left. After the pilot valve core moves to the left, the nozzle is driven to move to the right through the feedback assembly, thereby reducing the pressure on the left side of the receiver and increasing the pressure on the right side, thereby reducing the control pressure of the jet amplifier, forming a pressure gain compensation, and reducing the change in brake pressure.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] Based on the traditional brake servo valve, the present invention adds a pre-stage pressure gain compensation device, realizes closed-loop control of the jet amplifier control pressure through pressure gain compensation, reduces the influence of external environmental changes, improves the brake pressure stability of the brake servo valve, solves the problem of excessive brake pressure output by the brake servo valve, and improves the reliability of the aircraft hydraulic brake system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the control schematic diagram of a traditional brake servo valve.

[0016] Figure 2This is a control principle diagram of the pre-stage pressure gain compensation device in the present invention.

[0017] Figure 3 This is the control schematic diagram of the brake servo valve after adding a pre-stage pressure gain compensation device.

[0018] Figure 4 It is a front cross-sectional view of the brake servo valve in the present invention.

[0019] Figure 5 It is a side sectional view of the brake servo valve in the present invention.

[0020] Among them, 1-prestage pressure gain compensation device, 2-pilot valve core, 3-adjusting spring, 4-feedback component. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0022] Combination Figures 2 to 5 The present embodiment provides a brake servo valve pre-stage pressure gain compensation device, which is applied to the brake servo valve of the aviation hydraulic brake system to solve the problem of excessive brake pressure output by the brake servo valve, thereby improving the reliability of the aircraft brake system.

[0023] The device is located inside the housing of the brake servo valve and is arranged between the jet amplifier and the main valve core. The device includes a pilot valve core 2, an adjusting spring 3 and a feedback component 4. The adjusting spring 3 is connected to the side of the pilot valve core 2. The feedback component 4 is used to connect the pilot valve core 2 and the torque motor of the brake servo valve.

[0024] When the control pressure of the jet amplifier acts on the main valve core, it also acts on the pilot valve core 2. The pilot valve core 2 is displaced under the control pressure. During this process, the regulating spring 3 is compressed until the spring force and liquid pressure generated by the compression of the regulating spring 3 are balanced. Then, the feedback component 4 feeds back the displacement of the pilot valve core 2 to the torque motor, forming a negative feedback control of the torque motor and the pre-stage pressure gain, thereby compensating for the control pressure of the jet amplifier.

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

[0026] In this embodiment, the jet amplifier is composed of a jet tube, a nozzle and a receiver.

[0027] In this embodiment, the function of the pre-stage pressure gain compensation device 1 is to compensate for the zero offset and zero drift caused by changes in the system oil supply pressure, oil return pressure, oil temperature, etc.

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

[0029] After adding the pre-stage pressure gain compensation device 1, the pre-stage jet amplifier control pressure acts on the pilot valve core 2 in addition to the main valve core, causing the pilot valve core 2 to produce a displacement until the spring force and the hydraulic pressure generated by the valve core displacement are balanced. The displacement of the pilot valve core 2 is fed back to the torque motor through the feedback component 4 connecting the pilot valve core 2 and the torque motor, forming a negative feedback control of 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 increases, the control pressure of the pre-stage jet amplifier increases, and the feedback position of the pilot valve core 2 moves to the right compared to the original position. The spring force of the left adjusting spring 3 decreases, and the spring force of the right adjusting spring 3 increases, which generates a leftward thrust on the pilot valve core 2, causing the pilot valve core 2 to move left. After the pilot valve core 2 moves left, the nozzle is driven to move right through the feedback component 4, causing the pressure on the left side of the receiver to decrease and the pressure on the right side to increase, thereby reducing the control pressure of the jet amplifier, forming a pressure gain compensation, and reducing the change in brake pressure.

[0031] According to test data, when the system oil supply pressure of the traditional brake servo valve changes by 1MPa, the brake pressure changes by 0.8MPa. However, after adding the pre-stage pressure gain compensation device 1, when the system oil supply pressure changes by 1MPa, the brake pressure output by the brake servo valve only changes by 0.2MPa, and the improvement effect is significant. Therefore, after adding the pre-stage pressure gain compensation device 1 to the traditional brake servo valve, the closed-loop control of the jet amplifier control pressure is achieved through pressure gain compensation, which reduces the impact of external environmental changes, improves the brake pressure stability of the brake servo valve, solves the problem of excessive brake pressure output by the brake servo valve, and improves the reliability of the aircraft hydraulic brake system.

[0032] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A brake servo valve pre-stage pressure gain compensation device, characterized in that: The device is located inside the housing of the brake servo valve and is arranged between the jet amplifier and the main valve core. The device includes a pilot valve core, an adjusting spring and a feedback component. The adjusting spring is connected to the side of the pilot valve core. The feedback component is used to connect the pilot valve core and the torque motor of the brake servo valve. When the control pressure of the jet amplifier acts on the main valve core, it also acts on the pilot valve core. The pilot valve core is displaced under the control pressure. During this process, the adjusting spring is compressed until the spring force and liquid pressure generated by the compression of the adjusting spring are balanced. Then, the feedback component feeds back the displacement of the pilot valve core to the torque motor, forming a negative feedback control of the torque motor and the pre-stage pressure gain, thereby compensating the control pressure of the jet amplifier.

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

3. A brake servo valve pre-stage pressure gain compensation device as claimed in claim 2, characterized in that: The jet amplifier is composed of a jet tube, a nozzle and a receiver.

4. A brake servo valve pre-stage pressure gain compensation device as claimed in claim 3, characterized in that: When the oil supply pressure increases, the control pressure of the jet amplifier increases. At this time, the feedback position of the pilot valve core moves to the right compared to the original position, the spring force of the adjusting spring on the left side decreases, and the spring force of the adjusting spring on the right side increases, thereby generating a leftward thrust on the pilot valve core, causing the pilot valve core to move to the left. After the pilot valve core moves to the left, the nozzle is driven to move to the right through the feedback assembly, thereby reducing the pressure on the left side of the receiver and increasing the pressure on the right side, reducing the control pressure of the jet amplifier, forming a pressure gain compensation, and reducing the change in brake pressure.

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