Flow control valve with switching valve

Abstract

A flow control valve comprises an orifice which is formed in a supply passage of hydraulic fluid, and a spool valve for feeding part of hydraulic fluid supplied through the supply passage to a branch passage in response to a pressure differential across the orifice. A switching valve which switches a fluid circuit is assembled with the flow control valve. The switching valve comprises drive means which is directly and mechanically coupled to the spool valve for forcibly causing a displacement of the spool valve to open the branch passage while closing the supply passage. Hydraulic fluid is normally supplied through the supply passage, but when the drive means is actuated, hydraulic fluid can be supplied only to the branch passage. In alternate form, the drive means controls the opening or closing of the supply passage, and fluid pressure which obtains when the supply passage is closed is indirectly utilized to cause a displacement of the spool valve, thus opening the branch passage and closing the supply passage.