Patent ID: 6409142
Filing Date: 2002-06-25
Classification: F15B,Y10T

Abstract:
A hose rupture control valve unit (100; 100A; 100B) provided between a supply/drain port (102a) of a hydraulic cylinder (102) and a hydraulic hose (105) for controlling a flow rate of a hydraulic fluid coming out from said supply/drain port to said hydraulic hose in accordance with an external signal, wherein said valve unit comprises:a poppet valve body (5) serving as a main valve slidably disposed in a housing (3) provided with a cylinder connecting chamber (8) connected to said supply/drain port (102a), a hose connecting chamber (9) connected to said hydraulic hose (105), and a back pressure chamber (10), said poppet valve body being able to selectively cut off and establish communication between said cylinder connecting chamber and said hose connecting chamber, and changing an opening area depending on the shift amount thereof; a feedback variable throttle passage (11) provided in said poppet valve body, having an initial opening area when said poppet valve body is in a cutoff position, and increasing an opening area thereof depending on the shift amount of said poppet valve body; a first variable throttle portion (6a) disposed in a pilot passage (15a, 15b; 15a, 15h) connecting said back pressure chamber and said hose connecting chamber, and operated in accordance with the external signal to cut off and control a rate of pilot flow flowing from said cylinder connecting chamber to said hose connecting chamber through said feedback variable throttle passage, said back pressure chamber and said pilot passage; and a second variable throttle portion (50a) disposed in a sub-passage (15c, 15d; 15c, 15h) connecting said cylinder connecting chamber and said hose connecting chamber, and operated in accordance with the external signal to cut off and control a rate of sub-flow passing through said sub-passage.