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Title:
HYDRAULIC UNIT AND LIQUID PRESSURE CIRCUIT
Document Type and Number:
Japanese Patent JPH03121714
Kind Code:
A
Abstract:

PURPOSE: To produce large force in a simple structure by dividing a cylinder into high and low pressure spaces by a piston and taking second low pressure space as a balancing space to provide the sum of the discharge amount of a piston rod, the compressed volume of a hydraulic fluid and the stroke capacity of a pump.

CONSTITUTION: In a compression stroke of a pump 2 indicated by an arrow K, a hydraulic fluid flows into a high pressure space 1a so that a piston 10 is moved to the right, a discharged fluid flows from a low pressure space 1b through passages 7, 7', 8 into a balancing space 1c, at the compression end, a diaphragm 18 takes a broken-line position, and the volume of the balancing space 1c is obtained by subtracting the compressed volume of the fluid from the capacity of the pump 2 to which the discharge amount of a piston rod 11 sinking in the cylinder space 1a. In the suction stroke of the pump 2 indicated by an arrow S, a check valve 4 is opened so that the fluid in the balancing space 1c returns to the pump 2 through the passages 8, 7', a valve 5 cuts off a high pressure passage 6' so that the piston 10 holds its position, and the operation is repeated until extension arms 27, 28 are fully opened. When a valve 3 is switched, the flowing directions of the passages 6, 7 are changed so that in each compression stroke of the pump 2, the hydraulic fluid flows into the low pressure space 1b and the piston 10 is moved to the left.


Inventors:
Lindner, Dietmar
Application Number:
JP1990000247658
Publication Date:
May 23, 1991
Filing Date:
September 19, 1990
Export Citation:
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Assignee:
FAG KUGELFISCHER GEORG SCHAEFER & KGAA
International Classes:
B25B7/00; B23D15/14; B23D29/02; B25B1/18; B25B28/00; B66F1/08; F15B7/00; F15B15/18; (IPC1-7): B23D15/14; B25B7/00; B25B28/00; F15B7/00
Domestic Patent References:
JPS3414489Y1