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US 7,234,574 B2Granted
Damping coefficient switching-type hydraulic damper
AssigneeKajima Corporation
InventorsYoshinori Matsunaga, Haruhiko Kurino
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AssigneeKajima Corporation
InventorsYoshinori Matsunaga, Haruhiko Kurino
Estimating the term…
There is disclosed a damping coefficient switching-type hydraulic damper that may automatically switch a damping coefficient without needing supply of energy from the outside at all, and also may always surely exert an energy absorption capacity greater than that of a typical hydraulic damper. While a piston is moving in a direction A, a mechanical drive means composed of a straight gear and a crank mechanism allows an on-off control operation valve, that is, a flow regulating valve to be placed in a closed state, and a damping coefficient is switched to a maximum value Cmax. When a movement of the piston is turned in a direction B at a left-side maximum point of amplitude, the mechanical drive means works to once open the flow regulating valve to perform elimination of a load, so that the damping coefficient is switched to a minimum value (Cmin). When the piston further moves in the direction B, the mechanical drive means works to close the flow regulating valve again, and the damping coefficient is returned to the maximum value (Cmax). Similar working to the above is also applied to a right-side maximum point of amplitude, and seismic response control is attained with repetition of the above operations.
In a hydraulic damper having a cylinder, a piston movable in a reciprocating manner within said cylinder, hydraulic chambers provided at the opposite sides of the piston, and an on-off control valve provided in a passage for connecting both the hydraulic chambers and being on-off controlled to change a damping coefficient, a damping coefficient switching-type hydraulic damper, characterized by providing a hydraulic drive means in a hydraulic circuit of the cylinder for switching a damping coefficient without external electrical power supply by utilizing a change of hydraulic pressure at the time when the direction of movement of the piston is changed, said hydraulic drive means being structured so that a first damping coefficient is attained with the on-off control valve maintaining a closed state at the time when a movement of the piston in one direction causes hydraulic pressure in one hydraulic chamber to increase, and a second damping coefficient is attained with the on-off control valve once opened at the time when the movement of the piston is turned in the opposite direction to cause said hydraulic pressure to decrease, and afterwards, is switched to the first damping coefficient with the on-off control valve closed again in response to increasing hydraulic pressure in the other hydraulic chamber.
In a hydraulic damper having a cylinder, a piston movable in a reciprocating manner within said cylinder, hydraulic chambers provided at the opposite sides of the piston respectively connected by passages to a hydraulic circuit of the cylinder, and an on-off control valve provided in each of said passages and being on-off controlled to change a damping coefficient, a damping coefficient switching-type hydraulic damper, characterized by providing a hydraulic drive means for each of said hydraulic chambers in said hydraulic circuit of the cylinder, each of said hydraulic drive means being structured so that a first damping coefficient is attained with the on-off control valve maintaining a closed state at the time when a movement of the piston in one direction causes hydraulic pressure in one hydraulic chamber to increase, and a second damping coefficient is attained with the on-off control valve once opened at the time when the movement of the piston is turned in the opposite direction to cause said hydraulic pressure to decrease, and afterwards, is switched to the first damping coefficient with the on-off control valve closed again in response to increasing hydraulic pressure in the other hydraulic chamber.
In a hydraulic damper having a cylinder, a piston movable in a reciprocating manner within said cylinder, hydraulic chambers provided at the opposite sides of the piston, and an on-off control valve provided in a passage for connecting both the hydraulic chambers and being on-off controlled to change a damping coefficient, a damping coefficient switching-type hydraulic damper, characterized by providing a hydraulic drive means in a hydraulic circuit of the cylinder, said hydraulic drive means being structured so that a first damping coefficient is attained with the on-off control valve maintaining a closed state at the time when a movement of the piston in one direction causes hydraulic pressure in one hydraulic chamber to increase, and a second damping coefficient is attained with the on-off control valve once opened at the time when the movement of the piston is turned in the opposite direction to cause said hydraulic pressure to decrease, and afterwards, is switched to the first damping coefficient with the on-off control valve closed again in response to increasing hydraulic pressure in the other hydraulic chamber, said on-and off control valve and said hydraulic drive means being provided in common as a set to the hydraulic chambers.
Dependencies are inferred from the claim text.