SU270425A1 - PNEUMATIC POWER CYLINDER - Google Patents

Description

The invention relates to actuators and can be applied, for example, in an aircraft engine control system.

According to the main author. St. No. 115874 is known to a power cylinder in which when the stem is drawn in, the liquid is compressed in the compensation chamber with compressed air, when the stem is ejected, the compressed air is not supplied to the compensation chamber and some volume of liquid flows into this chamber when it flows. In this case, the hydraulic cavity of the cylinder is underfilled and a void is formed in it, as a result of which, at the beginning of the subsequent return stroke of the rod towards retraction, there is a sharp jerk of the rod, which disturbs the smoothness of movement of the cylinder driven mechanism.

The aim of the invention is to eliminate jerks when the rod is pulled in. This goal is achieved due to the fact that a shuttle valve is installed in the compensation chamber mounted separately on the housing, by means of which the compressed air presses the liquid in the compensator both during retraction and when the rod is pushed out. This ensures that both hydraulic cavities of the cylinder are completely filled and the TR.X-nical task of smooth operation of the cylinder and the mechanism driven by it is solved.

The drawing shows a cylinder, a general view. Inside the housing / with a fixed partition dividing the volume of the cylinder into two cavities L and B, the rod 2 is mixed, on which two pistons are rigidly mounted. Cavities A and B through the windows in the housing wall communicate with the cavities of the hydraulic locks 3 4, which, in turn, are connected by pipeline to each other and to the chamber of the compensator 5. A floating piston 6 is installed inside the compensator, which divides the volume of the compensator into two cavities: hydraulic and air, connected by an opening with a cavity of the shuttle valve 7.

The cavities of the cylinder A and B, the hydraulic locks 3, 4 and the compensator 5 are filled with liquid.

In this case, the piston 6 in the compensator is installed so as to ensure fluid intake during its thermal expansion, as well as to replenish hydraulic cavities during thermal compression of the fluid in case of its possible leakage through the seal.

The hydraulic locks are equipped with non-return valves 8. 9 and free pistons 10, 11. The non-return valves 8, 9 prevent the hydraulic locks and open easily to allow the fluid to flow in the opposite direction.

Loose pistons squeeze the check valves when compressed air is supplied to them. This ensures the flow of liquid from the cylinder cavity to the hydraulic lock. To push out the rod 2, compressed air simultaneously enters the cylinder, into the hydraulic lock 5 and to the shuttle valve. Moving from one extreme position to the other, the shuttle valve 7 opens the passage of compressed air to the floating piston 6. The free piston 10, moving, opens the check valve 8, ensuring the free passage of fluid from cavity A to cavity B. At the same time, the rod 2 starts to push out of the case. Pressing fluid from the floating piston 6 in the compensator as it flows from cavity A to B contributes to the complete filling of cavity B.

At the termination of a nodachi of compressed air check valves in hydraulic locks 3, 4 under

the action of the springs is closed, fixing the rod 2 in this position and preventing the movement of the rod from external load. To create a reverse motion for pulling in the rod, the compressed air is supplied simultaneously to the cylinder, to the hydraulic lock 4 and to the shuttle valve.

Subject invention

Pneumatic power cylinder but auth. St. No. 115874, characterized in that, in order to ensure smooth operation of the cylinder, the compensation chamber is provided with a shuttle valve and is mounted on the cylinder body.