Method for compensating for tolerances, play and elasticity in a motor-driven hydraulic valve

A method for detecting a mechanical play (Ws) in a system having a hydraulic valve and a valve drive drivable by an electrical current for driving the hydraulic valve, wherein a valve slide, which is driven by the valve drive, of the hydraulic valve is secured by spring action of a return spring which is configured, in a case of the valve drive being de-energized, to push the valve slide from any arbitrary valve slide position back into a neutral position of the valve slide, the method comprising steps of:

• a) moving the valve slide by the valve drive in a first direction (R1) up to a first valve slide position (P1) away from the neutral position of the valve slide;
• b) reducing the electrical current at the valve drive such that the valve slide is moved by the return spring in a second direction (R2) counter to the first direction (R1) back into the neutral position of the valve slide;
• c) moving the valve slide by the valve drive further in the second direction (R2) up to a defined second position (P2d) away from the neutral position of the valve slide and determining a first path (W1) from the neutral position of the valve slide to the defined second position (P2d);
• d) reducing the electrical current at the valve drive such that the valve slide is moved by the return spring in the first direction (R1) back into the neutral position of the valve slide;
• e) moving the valve slide by the valve drive in the second direction (R2) up to the defined second position (P2d) away from the neutral position of the valve slide and determining a second path (W1s) from the neutral position of the valve slide to the defined second position (P2d);
• and
• f) calculating the mechanical play (Ws) as a difference between the determined second path (W1s) and the determined first path (W1).