飞机液压系统活门介绍
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Basic Aircraft Systems—hydraulic system
VALVES-SELECTOR VALVES Open-center valve When the gear selector is moved to the GEAR UP position, poppets 2 and 5 open, and fluid from the pump flows around poppet 2, while the return fluid flows around poppet 5 as in Figure 8-37, view (C).
When the selector handle is in the neutral position, the appropriate poppet is off of its seat. Fluid flows straight through the valve from the pump to the next selector valve and on to the reservoir. [Figure 8-37, view (A)]
Basic Aircraft Systems—hydraulic system VALVES-SELECTOR VALVES
Open-center valve When the actuator reaches the end of its travel, the pump continues to produce a flow of fluid. A system relief valve (refer back to Figure 8-17) must off-seat to allow a flow back to the reservoir until the selector valve is moved to its neutral position. Some open-center valves have an automatic feature that causes them to move to the neutral position when the pressure rises to a specified value.
Basic Aircraft Systems—hydraulic system
VALVES-SELECTOR VALVES
Open-center valve The open-center valve is an open-center poppet-type selector valve utilized in an open-center hydraulic system (refer back to Figure 8-17).
Basic Aircraft Systems—hydraulic system VALVES-SELECTOR VALVES
Closed-center valve 1. Plug-type closed-center valves are often used in aircraft hydraulic systems. In one position, the pressure port and one actuator port are connected, while the other actuator port is connected to the return port. Rotating the selector handle ninety degrees reverses the connection between the actuator ports and the pressure and return lines. [Figure 8-38]
Pressure-control valves On the other hand, pressure-control valves adjust, regulate, or limit the amount of pressure in the system, or in any portion of the system.
Basic Aircraft Systems—hydraulic system HYDRAULIC SYSTEM VALVES
FLOW CONTROL VALVES For hydraulic components and systems to operate as intended, the flow of fluid must be rigidly controlled. Fluid must be made to flow according to definite plans. Many kinds of valve units are used for exercising such control. 1. selector valves (选择活门) 2. check valves (单向活门) 3. sequence valves (顺序活门) 4. priority valves (优先活门) 5. quick disconnect valve (快断活门) 6. hydraulic fuses (液压保险)
Basic Aircraft Systems—hydraulic system VALVES-SELECTOR VALVES
Open-center valve When the actuator reaches the end of its travel, the pump continues to produce a flow of fluid. A system relief valve (refer back to Figure 8-17) must off-seat to allow a flow back to the reservoir until the selector valve is moved to its neutral position. Some open-center valves have an automatic feature that causes them to move to the neutral position when the pressure rises to a specified value.
Basic Aircraft Systems—hydraulic system
VALVES-SELECTOR VALVES
Selector Valves One of the most familiar flow-control valves is the selector valve, which determines the direction of flow of fluid to retract or extend the landing gear, or to select the position of the wing flaps.
Basic Aircraft Systems—hydraulic system VALVES-SELECTOR VALVES
Closed-center valve 2. poppet-type selector valve When the gear selector handle is placed in the GEAR DOWN position (view B), poppets 1 and 4 are off-seated, and poppets 2 and 3 are seated.
Two commonly used types of selector valves:
Basic Aircraft Systems—hydraulic system VALVES-SELECTOR VALVES
Selector Valves Open-center valve The open-center valve directs fluid through the center of the valve back to the reservoir when a unit is not being actuated. Closed-center valve The closed-center valve stops the flow of fluid when it is in its neutral position. Both valves direct fluid from the pump to one side of the actuator and vent the opposite side to the reservoir.
Basic Aircraft system Valves of Aircraft Hydraulic System
Basic Aircraft Systems—hydraulic system HYDRAULIC SYSTEM VALVES
The valves used in hydraulic systems may be divided into: Flow-control valves. A flow-control valve selects the route of flow of the fluid through the system, and is not normally concerned with the pressure.
Basic Aircraft Systems—hydraulic system Poppet Valve
A poppet valve (also called mushroom valve) is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. The shaft guides the plug portion by sliding through a valve guide. In most applications a pressure differential helps to seal the valve and in some applications also open it.
Basic Aircraft Systems—hydraulic system
VALVES-SELECTOR VALVES
Closed-center valve 2. poppet-type selector valve (提升阀,菌形活门) A more positive shutoff of fluid may be provided by using a poppet-type selector valve, such as the one shown in Figure 8-39. In the GEAR UP position (view A), poppets 2 and 3 are off of their seats, and poppets 1 and 4 are seated. Fluid flows from the pump around poppet one to one side of the actuator piston and raises the landing gear. The fluid from the opposite side of the actuator piston is pushed out of the cylinder, around poppet three, and back to the reservoir.
Basic Aircraft Systems—hydraulic system
VALVES-SELECTOR VALVES Open-center valve When the gear selector is moved to the GEAR UP position, poppets 2 and 5 open, and fluid from the pump flows around poppet 2, while the return fluid flows around poppet 5 as in Figure 8-37, view (C).
When the selector handle is in the neutral position, the appropriate poppet is off of its seat. Fluid flows straight through the valve from the pump to the next selector valve and on to the reservoir. [Figure 8-37, view (A)]
Basic Aircraft Systems—hydraulic system VALVES-SELECTOR VALVES
Open-center valve When the actuator reaches the end of its travel, the pump continues to produce a flow of fluid. A system relief valve (refer back to Figure 8-17) must off-seat to allow a flow back to the reservoir until the selector valve is moved to its neutral position. Some open-center valves have an automatic feature that causes them to move to the neutral position when the pressure rises to a specified value.
Basic Aircraft Systems—hydraulic system
VALVES-SELECTOR VALVES
Open-center valve The open-center valve is an open-center poppet-type selector valve utilized in an open-center hydraulic system (refer back to Figure 8-17).
Basic Aircraft Systems—hydraulic system VALVES-SELECTOR VALVES
Closed-center valve 1. Plug-type closed-center valves are often used in aircraft hydraulic systems. In one position, the pressure port and one actuator port are connected, while the other actuator port is connected to the return port. Rotating the selector handle ninety degrees reverses the connection between the actuator ports and the pressure and return lines. [Figure 8-38]
Pressure-control valves On the other hand, pressure-control valves adjust, regulate, or limit the amount of pressure in the system, or in any portion of the system.
Basic Aircraft Systems—hydraulic system HYDRAULIC SYSTEM VALVES
FLOW CONTROL VALVES For hydraulic components and systems to operate as intended, the flow of fluid must be rigidly controlled. Fluid must be made to flow according to definite plans. Many kinds of valve units are used for exercising such control. 1. selector valves (选择活门) 2. check valves (单向活门) 3. sequence valves (顺序活门) 4. priority valves (优先活门) 5. quick disconnect valve (快断活门) 6. hydraulic fuses (液压保险)
Basic Aircraft Systems—hydraulic system VALVES-SELECTOR VALVES
Open-center valve When the actuator reaches the end of its travel, the pump continues to produce a flow of fluid. A system relief valve (refer back to Figure 8-17) must off-seat to allow a flow back to the reservoir until the selector valve is moved to its neutral position. Some open-center valves have an automatic feature that causes them to move to the neutral position when the pressure rises to a specified value.
Basic Aircraft Systems—hydraulic system
VALVES-SELECTOR VALVES
Selector Valves One of the most familiar flow-control valves is the selector valve, which determines the direction of flow of fluid to retract or extend the landing gear, or to select the position of the wing flaps.
Basic Aircraft Systems—hydraulic system VALVES-SELECTOR VALVES
Closed-center valve 2. poppet-type selector valve When the gear selector handle is placed in the GEAR DOWN position (view B), poppets 1 and 4 are off-seated, and poppets 2 and 3 are seated.
Two commonly used types of selector valves:
Basic Aircraft Systems—hydraulic system VALVES-SELECTOR VALVES
Selector Valves Open-center valve The open-center valve directs fluid through the center of the valve back to the reservoir when a unit is not being actuated. Closed-center valve The closed-center valve stops the flow of fluid when it is in its neutral position. Both valves direct fluid from the pump to one side of the actuator and vent the opposite side to the reservoir.
Basic Aircraft system Valves of Aircraft Hydraulic System
Basic Aircraft Systems—hydraulic system HYDRAULIC SYSTEM VALVES
The valves used in hydraulic systems may be divided into: Flow-control valves. A flow-control valve selects the route of flow of the fluid through the system, and is not normally concerned with the pressure.
Basic Aircraft Systems—hydraulic system Poppet Valve
A poppet valve (also called mushroom valve) is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. The shaft guides the plug portion by sliding through a valve guide. In most applications a pressure differential helps to seal the valve and in some applications also open it.
Basic Aircraft Systems—hydraulic system
VALVES-SELECTOR VALVES
Closed-center valve 2. poppet-type selector valve (提升阀,菌形活门) A more positive shutoff of fluid may be provided by using a poppet-type selector valve, such as the one shown in Figure 8-39. In the GEAR UP position (view A), poppets 2 and 3 are off of their seats, and poppets 1 and 4 are seated. Fluid flows from the pump around poppet one to one side of the actuator piston and raises the landing gear. The fluid from the opposite side of the actuator piston is pushed out of the cylinder, around poppet three, and back to the reservoir.