Abstract: A piston rod manufacturing method of manufacturing a piston rod by joining a solid rod main body and a solid rod head includes a first step of joining respective end surfaces of the rod main body and the rod head by friction welding; and a second step of performing boring process on an axial center portion from the rod head side so as to penetrate through a joining face between the rod main body and the rod head.

Abstract: A fluid pressure control apparatus includes a pilot control valve configured to control a pilot pressure guided from a pilot pump to the control valve and a load retaining mechanism installed in the main passage. The load retaining mechanism includes an operated check valve configured to permit a flow of the working fluid from the load-side pressure chamber to the control valve in accordance with a back pressure and a switch valve configured to switch an action of the operated check valve. The switch valve has a discharge position configured to discharge the working fluid in a back pressure chamber when the pilot pressure has been guided from the pilot control valve. When the switch valve is set to the discharge position, the working fluid in the back pressure chamber is discharged to a tank via a drain port of the pilot control valve.

Abstract: A hydraulic cylinder includes a rod inner passage that is formed in a piston rod along an axial direction and communicates a fluid pressure source and an interior of a cylinder tube; a plug that is inserted from an open end that opens to the interior of the cylinder tube of the rod inner passage; a lateral hole that is formed in the piston rod along a radial direction and extends so as to cross the rod inner passage; and a pin that is inserted into the lateral hole. In the piston rod, an inner-circumference screw portion is formed on an inner circumference of the rod inner passage, and on the plug, an outer-circumference screw portion that is screwed into the inner-circumference screw portion and an engagement portion that is engaged with the pin and locks rotation of the plug are formed.

Abstract: A damper that includes a piston reciprocally movable in a cylinder thereby dividing an interior of the cylinder into a first chamber located at an open end side and a second chamber located at a closed end side, a piston rod having a distal end to which the piston is connected and a rear end side protruding outward from the open end of the cylinder, a rod guide fixed to the open end of the cylinder and having a through hole through which the piston rod is reciprocally movable, and a seal which is provided in the rod guide so as to be located at a position spaced away from an outer end of a sliding surface of the through hole to the first chamber side by a distance longer than a maximum stroke width of the piston rod.

Abstract: A fluid pressure cylinder includes a cylinder tube, a piston and a solid piston rod. The piston rod includes a head-side passage defined by a head-side shaft hole extending in an axial direction, a head-side outer hole open on a part projecting from the cylinder tube and a head-side inner hole open to a head-side chamber and allowing communication between a head-side chamber and a fluid pressure source, and a bottom-side passage allowing communication between a bottom-side chamber and the fluid pressure source. The head-side shaft hole includes an opening end and a tip formed inside the piston rod. The opening end of the head-side shaft hole is sealed by a sealing member.

Abstract: A gas spring includes a rod body that has a base end side movable into and out of a cylinder body. The rod body is urged in a direction outward of the cylinder body by pressure from a gas sealed inside the cylinder body. A cylindrical cover body includes a base end portion connected to a distal end portion of the rod body that projects outside of the cylinder body. An end portion of the cover body receives a head end portion of the cylinder body inside a cylindrical cover member at an end portion of the cylinder body. The cover member covers a portion of the spring that would otherwise be exposed to the air between the end portion of the cover body and the end portion of the cylinder body when the cylinder body is contracted inside the cover body.