JPS63150824U - - Google Patents

Description

[Brief explanation of drawings]

Figures 1 to 3 show one embodiment, Figure 1 is a hydraulic circuit diagram, Figure 2 is a sectional view showing the restriction valve in Figure 1, and Figure 3 is a-a in Figure 2. FIG. 4 and 5 are circuit diagrams showing a conventional hydraulic circuit, and FIG. 6 is a sectional view showing a conventional restriction valve. 1: Hydraulic pump, 4: Travel motor, 5: Main pipe, 8: Make-up valve, 17: Make-up pipe, 18: Restriction valve, 18a:
Balance piston, 18b: throttle, 18c: secondary pressure chamber, 18e: pilot poppet, 18g: valve spool, 18j: bypass path, A: inlet port, B: outlet port, T: external drain port.

Claims (1)

[Scope of Claim for Utility Model Registration] A hydraulic power source, a travel hydraulic motor driven by the hydraulic power source, and a restrictor provided in the return pipe of the travel hydraulic motor and capable of setting the return pipe to a predetermined pressure. a restriction valve, which is connected to the inlet side of the restriction valve and causes pressure oil in the return line to flow into the main line when the main line pressure of the travel hydraulic motor is lower than the return line pressure; The restriction valve has a balance piston and a pilot poppet, and when the return pipe pressure exceeds a predetermined value and the pilot poppet opens and hydraulic pressure drains to the outside, the balance piston opens and returns. A hydraulic circuit for a hydraulic motor for traveling, characterized in that the balance piston can be opened by an external high pressure signal while pressure oil in a pipe flows into a tank.