Abstract: A hydraulic cylinder includes a cylinder tube, a piston, a piston rod, a bearing, and a seal, wherein the seal is configured to allow the flow of the operating liquid from the rod side chamber toward the anti-rode side chamber through the through passage when the pressure in the rod side chamber is higher than the pressure in the anti-rod side chamber.

Abstract: A single-acting hydraulic cylinder includes a cylinder head provided in the opening of the cylinder tube to allow the piston rod to be inserted, a bushing provided on an inner circumference of the cylinder head to slidably support the piston rod, and a housing recessed portion formed on the inner circumference of the cylinder head to receive the bushing forcibly inserted from the inlet portion. A bottom clearance filled with the grease is formed between the bottom face of the housing recessed portion and the bushing.

Abstract: A hydraulic cylinder includes a cylinder tube, a piston, a piston rod, a bearing, and a seal, wherein the seal is configured to allow the flow of the operating liquid from the rod side chamber toward the anti-rode side chamber through the through passage when the pressure in the rod side chamber is higher than the pressure in the anti-rod side chamber.

Abstract: A single-acting hydraulic cylinder includes a cylinder head provided in the opening of the cylinder tube to allow the piston rod to be inserted, a bushing provided on an inner circumference of the cylinder head to slidably support the piston rod, and a housing recessed portion formed on the inner circumference of the cylinder head to receive the bushing forcibly inserted from the inlet portion. A bottom clearance filled with the grease is formed between the bottom face of the housing recessed portion and the bushing.

Abstract: A piston bearing structure for a fluid pressure cylinder includes one seal ring which is housed in a housing groove of a piston and is held in sliding contact with a cylinder tube and two backup wear rings which is housed in a housing groove of a piston, is held in sliding contact with a cylinder tube and sandwiches the seal ring. The backup wear ring includes a pressure relief groove which faces the housing groove and extends over the backup ring portion and the wear ring portion, and the pressure relief groove allows opposite sides of the backup wear ring to communicate between the piston and the cylinder tube.

Abstract: A piston bearing structure for a fluid pressure cylinder includes one seal ring which is housed in a housing groove of a piston and is held in sliding contact with a cylinder tube and two backup wear rings which is housed in a housing groove of a piston, is held in sliding contact with a cylinder tube and sandwiches the seal ring. The backup wear ring includes a pressure relief groove which faces the housing groove and extends over the backup ring portion and the wear ring portion, and the pressure relief groove allows opposite sides of the backup wear ring to communicate between the piston and the cylinder tube.

Abstract: A piston seal of a liquid-operated cylinder includes a main seal ring that slidably contacts the inner circumferential surface of the cylinder tube; an O-ring that imparts a force causing an outer circumference of the main seal ring to move closer to the inner circumferential surface of the cylinder tube by pressing onto an inner circumference of the main seal ring; and a sub-seal ring that is disposed parallel to the main seal ring at a position further toward the cushion pressure chamber and is pressed by the main seal ring, as pressure from the drive pressure chamber is applied to the main seal ring, to slidably contact the inner circumferential surface of the cylinder tube.

Abstract: A piston seal (50) of a liquid-operated cylinder includes a main seal ring (51) that slidably contacts the inner circumferential surface (11) of the cylinder tube (10); an O-ring (52) that imparts a force causing an outer circumference of the main seal ring (51) to move closer to the inner circumferential surface of the cylinder tube (10) by pressing onto an inner circumference of the main seal ring (51); and a sub-seal ring (53) that is disposed parallel to the main seal ring (51) at a position further toward the cushion pressure chamber (6) and is pressed by the main seal ring (51), as pressure from the drive pressure chamber (5) is applied to the main seal ring (51), to slidably contact the inner circumferential surface of the cylinder tube (10).