US 4,321,793 AGranted

Integrated hydraulic circuit for off highway work vehicles

AssigneeKabushiki Kaisha Komatsu Seisakusho

InventorsKyoji Uranaka, Yasumasa Tarumizu, Hideo Hara, Masaaki Ichimura

Life of this patent

Estimating the term…

Loading patent…

Abstract

A pair of pumps deliver pressurized fluid to a steering control valve assembly controlling the operation of a steering cylinder. The steering control valve assembly diverts any excess of the incoming pressurized fluid to a hoist control valve assembly controlling the operation of a pair of implement hoist cylinders. The hoist control valve assembly also diverts any excess of the incoming fluid away from the hoist cylinder pair, this time to a retarder or brake system for cooling same. The retarder receives additional cooling fluid from a hydraulic torque converter, to which the fluid has been forced from another pump. On leaving the retarder the pressurized fluid is cooled and then delivered to a transmission lubricating circuit.

Claims6

Dependent claims

An integrated hydraulic power system for off-highway self-propelled work machines, comprising:

(a) first pump means for providing pressurized fluid;
(b) steering actuator means;
(c) steering control valve means communicating between the first pump means and the steering actuator means for controlling the operation of the latter;
(d) the steering control valve means having means for diverting away from the steering actuator means any excess of the pressurized fluid from the first pump means that is not demanded by the steering actuator means;
(e) implement actuator means;
(f) implement control valve means communicating between the steering control valve means and the implement actuator means for controlling the operation of the latter by receiving the diverted pressurized fluid from the former, the implement control valve means being adapted to divert away from the implement actuator means any excess of the incoming pressurized fluid that is not demanded by the implement actuator means;
(g) second pump means for providing pressurized fluid;
(h) a hydraulic torque converter communicating with the second pump means for receiving the pressurized fluid therefrom;
(i) a retarder communicating with the implement control valve means and with the torque converter for being cooled with the pressurized fluid received therefrom;
and
(j) a transmission lubricating circuit communicating with the retarder for receiving the pressurized fluid therefrom.

8 more elements

Dependencies are inferred from the claim text.