JPH0448343Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an improvement of an oil damper that does not seal air inside.

(Conventional technology) To fill the inside of the oil damper with hydraulic oil,
To prevent air from getting inside the damper, either assemble the damper in oil, or install valves at the bottom and head of the oil damper to bleed air and fill with oil at the same time after assembly. .

(Problem that the invention aims to solve) However, assembling the oil damper in oil is not only inefficient, but also requires some fumbling.
It takes a lot of effort to wipe the oil-stained damper clean.

On the other hand, those equipped with valves require space for installing the valves, and also have a large number of parts, leading to increased costs.

An object of the present invention is to provide an oil damper that has a simple structure and can be efficiently filled with hydraulic oil after assembly.

(Means for Solving the Problems) The present invention includes a cylinder containing a piston that slides through a piston rod, an outer tube that is elastically deformed on the outside of the cylinder, and an upper portion defined by the piston. The chamber and the lower chamber are communicated via a check valve provided on the piston, and an oil reservoir chamber formed between the cylinder and the outer tube is
In the oil damper, which communicates with the upper chamber via the damping valve and the lower chamber via the check valve, a through hole is provided in the axial direction of the piston rod, and a check valve is inserted in this through hole, while the cylinder and A cap that seals the bottom of the outer tube is provided so that it can be fastened freely.

(Operation) The oil damper is filled with hydraulic oil while being pressurized against the check valve through the through hole of the piston rod. By loosening the cap at this time, the air will be expelled from this gap and the hydraulic oil will fill up.

As the piston rod expands and contracts, hydraulic oil circulates in one direction inside the damper, so by alternately repeating the injection of hydraulic oil and the expansion and contraction of the piston rod, the air inside the damper is replaced with hydraulic oil while pushing air in the same direction. be able to.

(Embodiment) In the figure, a piston 2 is housed in a cylinder 1 so as to be freely slidable, and a piston rod 3 passes through a bearing portion 4. An outer tube 5 made of an elastic material such as rubber or synthetic resin is disposed on the outside of the cylinder 1. The interior of the cylinder 1 is defined by the piston 2 into an upper chamber 6 and a lower chamber 7, and an oil reservoir chamber 8 is further formed between the cylinder 1 and the outer tube 5.

The upper chamber 7 communicates with the oil reservoir chamber 8 through a damping valve 9 provided on the bearing portion 4, and the oil reservoir chamber 8 communicates through a check valve 12 on the cylinder bottom 11. A check valve 14 is installed in the piston 2 in a passage 13 that communicates the upper and lower chambers 6 and 7.
It opens during the compression stroke to release hydraulic oil from the lower chamber 7 to the upper chamber 6.

A check valve 15 for injecting hydraulic oil is provided opposite the check valve 14. These check valves 14 and 15 are provided with a common check spring 16, and are biased toward the seat portion.

A through hole 17 is formed in the piston rod 3 in the axial direction, and the end thereof is sealed with a blind plug 18.

Check valve 15 has check spring 16
When pressure is applied to the side, the through hole 17 is closed.

An end bolt 19 is screwed into the cylinder bottom 11, and a cap 2 fitted onto the end bolt 19 is screwed into the cylinder bottom 11.
0 is tightened by nut 21.

The outer tube 5 is tightly fitted around the cap 20 and the outer periphery of the bearing portion 4, and repeatedly expands and contracts as hydraulic oil enters and exits.

The system is constructed as described above, and its operation will be explained next.

In the pressure side stroke where the piston rod 3 enters, the hydraulic oil in the lower chamber 7, which contracts, pushes open the check valve 14 of the piston 2 and flows into the upper chamber 6.
Further, the hydraulic oil corresponding to the rod intrusion volume passes through the damping valve 9 and flows into the oil reservoir chamber 8, and at this time, the damping valve 9 generates a predetermined damping force.

In the oil reservoir chamber 8, the outer tube 5 expands as hydraulic oil flows in to absorb the fluctuation (increase) in oil amount.

Next, in the extension stroke when the piston rod 3 comes out, the cylinder bottom 11 moves against the expanding lower chamber 7.
Hydraulic oil is sucked in from the oil reservoir chamber 8 through the check valve 12 in the upper chamber 6, and hydraulic oil in the upper chamber 6 flows to the oil reservoir chamber 8 through the damping valve 9. Occur.

In this way, the oil damper expands and contracts while circulating the hydraulic oil in one direction. Fluctuations in the oil amount corresponding to the rod intrusion volume are absorbed by the expansion and contraction of the outer tube 5, and a This eliminates the need to fill in gas.

The oil damper is filled with hydraulic oil as follows.

With the piston rod 3 fully compressed and the cap 20 loosened, hydraulic oil is injected into the through hole 17 from the tip of the piston rod 3 with the cylinder bottom 11 facing upward. When injection is performed while applying a certain amount of pressure, the check valve 15 is pushed open and the hydraulic oil that flows into the upper chamber 6 flows into the oil reservoir chamber 8 through the damping valve 9, and as the oil level rises, the hydraulic oil flows into the cap. Internal air escapes from the gap between the end bolt 19 and the end bolt 20. When the damper is almost full of hydraulic oil, the oil oozes out along with the air.
This time, with piston rod 3 on top, stretch piston rod 3 once and then gently push it in. As a result, the air remaining in the lower chamber 7 is transferred to the upper chamber 6 via the check valve 14, and the cylinder is fully expanded again, and the cylinder bottom 11 is placed upwards and hydraulic oil is injected while applying pressure. Then, the air in the upper chamber 6 is pushed out to the oil reservoir chamber 8 and further discharged to the outside through the gap between the cap 20 and the end bolt 19.

By repeating such operations, it is possible to fill the chamber with hydraulic oil while expelling the air inside. Once the inside of the damper is filled with hydraulic oil, the cap 20 and nut 21 are tightened, and the end of the piston rod 3 is sealed with the blind plug 18.

(Effects of the invention) As described above, according to the invention, the hydraulic oil can be filled after the oil damper is assembled, so that the work efficiency is significantly improved. In addition, the valve for filling hydraulic oil does not protrude to the outside, reducing the damper installation space and the number of parts, and providing a damper that can exert stable damping force without aeration.

[Brief explanation of the drawing]

The drawing is a sectional view showing an embodiment of the present invention. 1... Cylinder, 2... Piston, 3... Piston rod, 5... Outer tube, 6... Upper chamber, 7... Lower chamber, 8... Oil reservoir chamber, 9... Damping valve, 14, 15... ...Check valve, 17...
...Through hole, 19...End bolt, 20...Cap, 21...Nut.

Claims (1)

[Scope of utility model registration request] A check valve in which a piston that slides through a piston rod is housed in a cylinder, an outer tube that is elastically deformed is arranged on the outside of the cylinder, and an upper chamber and a lower chamber defined by the piston are provided in the piston. In the oil damper, the oil reservoir chamber formed between the cylinder and the outer tube is communicated with the upper chamber through the damping valve, and the lower chamber is connected through the check valve. A through hole is provided in the
An oil damper characterized in that a check valve is interposed in the through hole, and a cap that seals the bottom of the cylinder and the outer tube can be freely fastened.