Power steering

A torque booster is a type of servo hydraulic actuator in which either a hydraulic motor or a rotary hydraulic motor serves as a hydraulic motor .

This type of hydraulic booster usually uses a hydraulic distributor with a rotary valve, made in the form of a crane, while the distributor has a tracking sleeve.

The structural diagram of the torque booster, made on the basis of a rotary hydraulic motor

An example of a torque booster is shown in the figure. In the steady state, the pressure to the left and right of the plate 1 connected to the hydraulic motor shaft are equal to each other. In this design, fluid flows through the spool channels${\displaystyle \mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">e</span></span>}}$ {\ displaystyle e} and${\displaystyle \mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">f</span></span>}}$ {\ displaystyle f} , and is assigned to the channel${\displaystyle \mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">m</span></span>}}$ {\ displaystyle m} . When turning the plug 3 of the valve 3 clockwise, connected, for example, to the steering wheel, relative to the sleeve, resistance to the flow of liquid supplied through the channel${\displaystyle \mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">e</span></span>}}$ {\ displaystyle e} will decrease. As a result, the pressure to the left of plate 1 will increase. At the same time, the resistance to the flow of fluid discharged along the channel will decrease${\displaystyle \mathrm{<span\; class="mwe-math-element"><span\; class="mwe-math-mathml-inline\; mwe-math-mathml-a11y"\; style="display:\; none;">m</span></span>}}$ {\ displaystyle m} - as a result, the pressure to the right of plate 1 will decrease. A pressure differential will occur on the plate, as a result of which the plate together with the sleeve will move in the same direction (clockwise) into which the valve plug was previously turned. Resistance to fluid flow will increase, and the pressure to the right and left of the plate will equalize.

In the above hydraulic booster circuit, the spool 3 performs the function of a mismatch of input and output shafts.