The design and principle of operation of the power steering
1 - Shaft
2 - Torsion
3 - Screw
4, 5 - Spools
6 - Piston
7 - Circulation tube
8 - Shaft with gear sector
9, 10 - Inlet valves
11, 12 - Radial channels
13, 14 - Exhaust valves
15 - Pump
16 - Reservoir
17 - Safety valve
18 - Control valve
Inside the steering gear housing is the steering gear assembly, control spool and slave cylinder. Through the torsion bar (2) steering shaft (1) elastically connected to the screw (3) and hard - with spools (4 and 5). The spools are built into the distributor housing in a transverse position relative to the screw axis. Communication between the piston (6) and screw (3) through a closed ball chain. When turning the screw, the circulation tube (7) takes the balls from one end of the chain and moves them to the other end. Piston (6) connected through gearing to the shaft (8), having a jagged sector. The special tooth profile of the shaft sector makes it possible to eliminate backlash with the help of an adjusting screw. In the neutral position of the spools (4 and 5) the oil supplied by the pump circulates in the steering mechanism and through the open inlet and outlet control edges has free access to the cylinder. The hydraulic actuator comes into operation when the spools are released from the neutral position. This occurs when the force from the steering wheel or from the steering arm is transmitted to the screw through the toothed shaft and the piston. In this case, the torsion bar acts as a connecting element (2). Its flexible part has the ability to deform and return the spools again after removing the force from the steering wheel to the neutral position. When the spools are moved out of the neutral position, the oil is also directed to the working cylinder - this provides power support in the movement of the steering shaft and counteraction to impacts caused by road roughness. Steering wheel in neutral position: from the vane pump, oil flows into the distributor housing, through the inlet channels (9 and 10) - to radial channels (11 and 12). From there, it flows further through the connecting holes to the right and left cylinder chambers, and then through the open exhaust channels (13 and 14) back to the tank. Steering wheel turned clockwise/counterclockwise: spool (4/5) moves to the right, and the inlet (9/10) opens. spool (5/4) moves to the left, and the inlet (10/9) closes. Thus, the oil enters the right / left cylinder cavity, is pushed out of the left / right cylinder cavity and returns to the reservoir.