Title:
FLOW RATE AND PRESSURE CONTROL DEVICE FOR SERVOMOTOR DRIVE HYDRAULIC PUMP
Document Type and Number:
Japanese Patent JP3171473
Kind Code:
B2
Abstract:
PURPOSE: To provide smooth control switching without any hunting phenomenon by providing a closed loop system for flow rate control and a closed loop system for pressure control, and by inputting to an amplifier the smaller one out of outputs from compensating elements of respective closed loop control system for switching each of closed loop systems.
CONSTITUTION: This device comprises an F/V converter (a flow rate detecting means) 25 for converting flow rate to a voltage corresponding to the number of revolutions of a servomotor 22 for driving a hydraulic pump 21, and also a flow rate and pressure compensating part 30 formed alongside a hydraulic pump part 20 provided with a pressure sensor 26 for detecting a discharge pressure of the hydraulic pump 21. Deviation between an instructed value of flow rate and a detected value of flow rate and deviation between an instructed value of pressure and a detected value of pressure are detected by means of respective deviation detecting parts 31 and 32, and the deviations are input to an amplifier 23 through the first and the second compensating elements 33 and 34 for having flow rate control or pressure control carried out. That is, only the output having a smaller absolute value out of outputs from respective compensating elements 33 and 34 is input to the amplifier 23 through a control system switching circuit 35 for switching the closed loop systems.
Inventors:
Hirotoshi Nakao
Yasuo Shimomura
Yasuo Shimomura
Application Number:
JP677592A
Publication Date:
May 28, 2001
Filing Date:
January 17, 1992
Export Citation:
Assignee:
Tokimec Co., Ltd.
International Classes:
F15B9/00; F04B49/06; (IPC1-7): F04B49/06
Domestic Patent References:
| JP347489A | ||||
| JP64110884A | ||||
| JP5890217A | ||||
| JP5892002A | ||||
| JP271305A |
Attorney, Agent or Firm:
Takashi Ohsawa