| 摘要 |
A cushion device for a hydraulic cylinder of a dump truck is provided to buffer actively without shaking a hydraulic cylinder and a deck by installing a valve stopper and a spindle cushion member, to manufacture easily by decreasing the size of an oil tank, and to increase assembling efficiency by reducing the number of piston rings. A hydraulic cylinder for a dump truck includes a tube(10), a base(20) combined with a rear part of the tube, a grand(30) combined with a front part of the tube, a piston(40) reciprocating in the tube, and a rod(50) combined with the piston and extended through the grand. A cushion device comprises an extension supply passage(61) formed in a base(20), a return passage(62) formed in an outer periphery of the tube, a valve stopper(70) installed in the piston and protruded to the grand, a spindle cushion member(80) installed at a rear end of the rod, a valve cushion(81) mounted in the base and penetrated by the spindle cushion member, and a spring(82) mounted between the rear end of the rod and the valve cushion. The valve stopper is composed of a stopper rod(71) penetrating the piston, a rear expansion part(72) combined with a rear part of the stopper rod and fitted to a rear end of the piston, and a front expansion part(73) combined with a front end of the stopper rod and combined with a front end of the piston. |
