JPH03260476A - Hydraulic cylinder - Google Patents

Abstract

PURPOSE:To prevent packing movement or slipping-off between a slipoff preventive cylinder and a piston by fitting a dust seal and packing in the bore of the slipoff preventive cylinder at its outer end, and fitting a bearing and a stopper collar only at the inner end of the packing. CONSTITUTION:A slipoff preventive cylinder 4 is provided, wherein a seal groove 17 is formed for fitting of a dust seal 5 at the outer end, and a partitioning 18 is formed to be in tight fit on the periphery of a piston 3 in the backmost of the groove 17, and further a packing groove 19 is formed for fitting of a packing 6 in the backmost of the partitioning 18. A bearing fit part 22 in the spacing to admit fitting of bearing 7 in a plurality of places is formed in the part backmore than another partitioning 21, and at the foremost a stopper groove 23 is provided for fitting of a stopper collar 8. Because the bearing 7 is not installed at the partitioning 18, the bearing fit part 22 is not formed large. Accordingly there is no such fear that the packing 6 having received the oil pressure makes elastic deformation and movement, to allow the fluid bearing effect to be maintained good, with oil leak prevented, and thus the durability of the bearing 7 can be enhanced.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a hydraulic cylinder that can expand and contract by pushing out a piston using hydraulic pressure, and is used for raising and lowering the working part of a tractor, and for other hydraulic cylinders such as industrial machinery and equipment. can.

(Prior art and problem to be solved by the invention) In order to slidably fit a piston inside a hydraulic cylinder, it is necessary to prevent the piston from being pulled out or to prevent oil leakage. There is. For this reason, a small-diameter retaining cylinder is provided at the cylinder mouth of the hydraulic cylinder to prevent the piston from being pulled out, and a gap is formed between the inner cylinder of the retaining cylinder and the outer circumferential surface of the piston to prevent the piston from pulling out. Includes bearings, etc. However, if a bearing is inserted, this gasket will become 1/1 due to the hydraulic pressure from inside the cylinder.
Due to the elastic deformation, the piston may be pushed out in the ejecting direction, which tends to cause oil leakage and wear of the bearing portion. This invention aims to prevent the packing from moving or coming out between the locking cylinder and the piston.

(Means for Solving the Problems) This invention has a dust seal 5° and A hydraulic cylinder is constructed by fitting a packing 6, and fitting a bearing 7 and a stopper collar 8 only on the inner end side of the packing 6.

(Operation and Effects of the Invention) When fitting the piston 3 into the cylinder l, the piston 3 is fitted with a retaining cylinder 4, a dust seal 5,
The packing 6, the bearing 7, the stopper collar 8, etc. are fitted together, and the piston 3 in this state is fitted into the cylinder 1. Further, a retaining cylinder 4 fitted to the piston 3 is fitted and fixed into the cylinder mouth portion 2, and a stopper collar 8 at the inner end of the retaining cylinder 4 prevents the piston 3 from coming off. It is.

By supplying and discharging hydraulic pressure into the cylinder 1, a portion of the oil passes between the outer peripheral surface of the piston 3 and the stopper collar 8 and reaches the bearing 7, and while lubricating this bearing, the oil is removed by the packing 6. It is possible to stop the flow of water to the outside.

Since the inner circumferential surface of the retaining cylinder 4 between the packing 6 and the dust seal 5 on the tip side is not provided with a bearing, it can be brought close to the curved surface of the piston 3 to form an extremely small gap. Even if hydraulic pressure is applied to the packing 6,
The piston 3 is less likely to be pushed outward through the extremely small gap between the retaining cylinder 4 and the piston 3, and the bearing 7 can maintain smooth sliding of the piston 3 and prevent oil leakage. can.

(Example) In addition, in the rotation, the cylinder E has a mounting part 9 at one end, and the other end is opened as the cylinder mouth 2, and the cylinder mouth 2 has an inner diameter smaller than that of the cylinder 1. A large outer cylinder 10 is fixed by welding or the like, and a screw 11 is formed in the inner RW at the tip of the outer cylinder 10. Also, cylinder 1
An oil supply port 12 and an oil drain port 13 that communicate with the hydraulic circuit and supply and discharge hydraulic pressure are provided at both ends of the oil pressure pump.

The piston 3 fits into this cylinder 1.

A gap portion 14 is formed between the inner circumferential surface of the cylinder and the outer circumferential surface of the piston 3 for supplying hydraulic pressure. A stopper ring 15 is fitted to the inner end of the piston 3 and protrudes to a diameter slightly larger than the diameter of the piston 3, and a mounting portion 16 is provided at the outer end.

The retaining cylinder 4 has a seal groove 17 formed at its outer end into which the dust seal 5 is fitted, and a partition 18 having an appropriate width formed at the inner side of the seal groove 17 so as to fit closely against the outer peripheral surface of the piston 3. Furthermore, a packing groove 19 into which the packing 6 is fitted is formed on the back side of the partition portion 18. A partition part 21 is provided on the back side of this packing groove 19 to form a gap part 20 between it and the outer peripheral surface of the piston 3 through which oil can freely enter and exit. This partition part 2
On the far side from 1, a bearing fitting part 22 is formed with a spacing that allows the bearing 7 to be fitted in a plurality of places, and a stopper groove 23 in which the stopper collar 8 is fitted is provided at the tip of this bearing fitting part 22. A gap 24 is formed between the piston 3 and the inner peripheral surface of the stopper collar 8 that fits into the stopper groove 23, allowing oil to freely enter and exit. Also, the retaining cylinder 4
A screw 25 is formed on the outer peripheral surface of the cylinder 10 to be screwed into the threaded part of the outer cylinder 10, and by these screws, the piston 3 is assembled into the cylinder 1, and hydraulic pressure is sent from the oil filler port 12. The piston 3 can be pushed outward, or the oil can be drained from the oil drain port 13 and the piston 3 can be retracted into the cylinder 4 by the load pressure.

The hydraulic pressure in the cylinder 1 also acts on the gap between the inner peripheral surface of the retaining cylinder 4 and the outer peripheral surface of the piston 3, and flows from the gap 24 through the bearing fitting part 22 into the packing groove 19 while lubricating the bearing. Then, the packing 6 in the packing groove 19 is pressed against the partition portion 18. Therefore, the hydraulic pressure is stopped by this gasket 6.

Loads such as rocking, tilting, etc. caused by sliding of the piston 3 are supported by each bearing 7 and transferred within the sliding housing. Since this bearing 7 is not provided in the partition part 18, the bearing fitting part 22 for fitting this bearing is not formed large, so that the packing 6 that receives the hydraulic pressure is not elastically deformed and moved. Therefore, the hydrodynamic bearing effect can be maintained well, oil leakage can be prevented, and the durability of the bearing 7 can be increased.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which FIG. 1 is a partially sectional front view, and FIG. 2 is a partially enlarged sectional view. (Explanation of symbols) Cylinder piston dust seal bearing 2 Cylinder mouth 4 Preventing cylinder 6 Packing 8 Stopper collar

Claims (1)

[Claims] A dust seal 5 and a packing 6 are fitted on the outer end side of the inner peripheral surface of a locking cylinder 4 that closes the cylinder mouth 2 of the cylinder 1 to prevent the piston 3 from slipping out. A hydraulic cylinder in which a bearing 7 and a stopper collar 8 are fitted only on the side.