Title:
TORQUE CONTROL DEVICE OF HYDRAULIC CONSTRUCTION MACHINE
Document Type and Number:
Japanese Patent JP2760706
Kind Code:
B2
Abstract:
PURPOSE: To improve the efficiency by lowering pump input torque to the value less than that in a designated value, when operating oil temperature or motor cooling water temperature exceeds a desiganted value at the time of driving a variable capacity hydraulic pump by a motor.
CONSTITUTION: At the time of driving a variable capacity hydraulic pump 1 by a motor 27 to operate hydraulic actuators 4, 21, the operating oil temperature is detected by an oil temperature sensor 56. When the detected oil temperature exceeds a designated value, input torque is lowered to the value less than that in a desigated value to prevent overheat. Subsequently, the input torque when the oil temperature is less than a designated value is set comparatively high to improve the driving efficiency in the case of low oil temperature. The cooling water temperature of the motor 27 is detected to control the input torque in the same manner. Further, there is provided a motor rotating speed control means, whereby when the detected temperature exceeds a designated value, the rotating speed may be increased. Thus, the driving efficiency of an actuator can be improved without overheating the motor.
Inventors:
KOJIMA MITSUGI
TATSUMI AKIRA
TATSUMI AKIRA
Application Number:
JP18078492A
Publication Date:
June 04, 1998
Filing Date:
July 08, 1992
Export Citation:
Assignee:
HITACHI KENKI KK
International Classes:
E02F9/22; E02F9/00; F15B11/00; F15B11/05; (IPC1-7): E02F9/22; F15B11/00; F15B11/05
Domestic Patent References:
| JP458040A | ||||
| JP1277630A |
Attorney, Agent or Firm:
Fuyuki Nagai