Eaton Hydraulic Series 76 Variable Motor Stroking Valve Control

This stroking valve is a solenoid that is managed by a (12 volt dc) valve that works on models 33- 76 series. The valve helps the motor to it’s highest displacement or to the lowest displacement. The valve has a 2 position, 4 way valve that is spring biased and pilot enforced by the solenoid valve.

To get to the low displacement the stroking valve electrical solenoid is turned off. The pilot pressure rises behind the large control piston to subdue the biased control spring force to shift the control spool. Then the control pressure is pushed up to the servo piston, making the swashplate go to the maximum displacement for the low working speed range.

To get to the highest displacement, the valve is turned on. The control pilot pressure is pushed thru a small orifice, then goes around the control piston and thru the activated solenoid valve and back thru the control piston, then to the motor housing. Thus making both ends pushed together. This makes the bias spring hold onto the control spool, pushing the control pressure to the lower servo piston. Making the swashplate to go to the lowest displacement for the high functional speed range. The upper pistons posses spacers and shims to control the lest amount of swashplate angle to hit upon system demands.

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