Hydraulic drive unit
AssigneeKomatsu Ltd.
InventorsKazuhiro Maruta, Nobumi Yoshida
Life of this patent
Estimating the term…
Abstract
A balance of force acting on a pool 21 of a control valve 20 is expressed by (P1−P3)·A=F+f When it is assumed that a pressure difference P1−P2 before and after a throttle 42 is ΔP12 to modify the above expression, an expression ΔP12·A+(P2−P3)·A=f+F is obtained. According to the present invention, the force ΔP12·A corresponding to the pressure difference ΔP12 before and after the second throttle 42 of the first term of the left-hand side is applied to the control valve 20 as a force capable of canceling the flow force f at the first term of the right-hand side.
Claims14
A hydraulic drive unit comprising:
- a hydraulic source which increases a discharge flow rate according to an increase in rotational speed;
- a throttle through which pressure oil discharged from the hydraulic source passes;
- hydraulic equipment which operates upon inputting the pressure oil having passed through the throttle;
- and
- a control valve which controls the pressure oil passing through the throttle so that the flow rate passing through the throttle becomes a prescribed level when the rotational speed becomes a prescribed level or more, wherein:
- means for producing a force for canceling a flow force produced by the control valve is applied to the control valve.
A hydraulic drive unit comprising:
- a hydraulic source which increases a discharge flow rate according to an increase in rotational speed;
- a first throttle through which pressure oil discharged from the hydraulic source passes;
- hydraulic equipment which operates upon inputting the pressure oil having passed through the first throttle;
- and
- a control valve which controls the pressure oil passing through the first throttle so that the flow rate passing through the first throttle becomes a prescribed level when the rotational speed becomes a prescribed level or more, wherein:
- a second throttle which produces a pressure difference corresponding to a force for canceling the flow force produced by the control valve is disposed;
- and
- the force corresponding to the pressure difference before and after the second throttle is applied to the control valve in a direction to cancel the flow force.
Dependencies are inferred from the claim text.