CUSHION VALVE DEVICE AND MULTI-CUSHION VALVE UNIT INCLUDING THE SAME
First Claim
1. A cushion valve device disposed between an operating valve and a switching valve, the operating valve being configured to supply pilot oil with a pressure corresponding to an operating amount of an operating tool to one of a first supply/discharge passage and a second supply/discharge passage in accordance with an operating direction of the operating tool, and connect another one of the first supply/discharge passage and the second supply/discharge passage to a tank, the switching valve being configured to switch a direction of hydraulic oil flowing to an actuator in accordance with a pressure difference between a first pilot passage connected to the first supply/discharge passage and a second pilot passage connected to the second supply/discharge passage,the cushion valve device comprising:
- a valve block including a first passage, a second passage, and a first discharge passage, the first passage including a first throttle and being disposed between the first supply/discharge passage and the first pilot passage, the second passage being disposed between the second supply/discharge passage and the second pilot passage, the first discharge passage branching off from the first passage between the first throttle and the first pilot passage and connecting the first passage and the tank; and
a first pilot-to-open check valve configured to open the first discharge passage when the pressure of the pilot oil that flows through the second supply/discharge passage has become higher than or equal to a predetermined pressure, and close the first discharge passage when the pressure of the pilot oil that flows through the second supply/discharge passage has become lower than the predetermined pressure, whereinwhen the pressure of the pilot oil that flows through the second supply/discharge passage is lower than the predetermined pressure, the first pilot passage is connected to the tank via the first passage and the first supply/discharge passage.
1 Assignment
0 Petitions
Accused Products
Abstract
A cushion valve device includes a valve block that includes first, second and first discharge passages. The first passage is disposed between a first supply/discharge passage of an operating valve and a first pilot passage of a switching valve, and includes a first throttle. The second passage is between a second supply/discharge passage of the operating valve and a second pilot passage of the switching valve. The first discharge passage connects to the first passage and a tank. A first check valve is provided on the first discharge passage. The first check valve includes: a poppet valve element configured to be seated on a valve seat portion, thereby closing the first discharge passage; and a piston configured to move the poppet valve element when the pressure of pilot oil in the second supply/discharge passage has become higher than or equal to a predetermined pressure, thereby opening the first discharge passage.
6 Citations
8 Claims
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1. A cushion valve device disposed between an operating valve and a switching valve, the operating valve being configured to supply pilot oil with a pressure corresponding to an operating amount of an operating tool to one of a first supply/discharge passage and a second supply/discharge passage in accordance with an operating direction of the operating tool, and connect another one of the first supply/discharge passage and the second supply/discharge passage to a tank, the switching valve being configured to switch a direction of hydraulic oil flowing to an actuator in accordance with a pressure difference between a first pilot passage connected to the first supply/discharge passage and a second pilot passage connected to the second supply/discharge passage,
the cushion valve device comprising: -
a valve block including a first passage, a second passage, and a first discharge passage, the first passage including a first throttle and being disposed between the first supply/discharge passage and the first pilot passage, the second passage being disposed between the second supply/discharge passage and the second pilot passage, the first discharge passage branching off from the first passage between the first throttle and the first pilot passage and connecting the first passage and the tank; and a first pilot-to-open check valve configured to open the first discharge passage when the pressure of the pilot oil that flows through the second supply/discharge passage has become higher than or equal to a predetermined pressure, and close the first discharge passage when the pressure of the pilot oil that flows through the second supply/discharge passage has become lower than the predetermined pressure, wherein when the pressure of the pilot oil that flows through the second supply/discharge passage is lower than the predetermined pressure, the first pilot passage is connected to the tank via the first passage and the first supply/discharge passage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification