JPH0716885Y2 - Cylinder device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a cylinder device operated by compressed air.

[Prior Art] An oil-impregnated bearing is usually provided in a piston rod penetrating portion of an air cylinder device, and a lip-shaped rod packing is provided on an inner end side or an outer end side of the bearing to form a cylinder chamber and an external portion. The structure is such that a sealing action is performed between and.

[Problems to be Solved by the Invention] However, in the above-described seal structure of the piston rod penetrating portion, the fluctuation of the air pressure on the cylinder chamber side of the penetrating portion directly acts on the rod packing, so that the piston of the rod packing is The surface contact pressure on the rod fluctuates abruptly, the sealing property of the rod packing becomes unstable, and the durability deteriorates.

Further, due to such instability of the sealing property of the rod packing and deterioration of durability, the lubricant is easily scattered from the bearing of the piston rod penetrating portion, and therefore the clean space is contaminated with the lubricant and the like. In addition, the durability of the piston rod, bearing, etc. is reduced.

An object of the present invention is to provide a cylinder device capable of stabilizing the sealing performance by a rod packing and improving durability, and reliably preventing the lubricant from scattering from the bearing at the piston rod penetrating portion. To do.

[Means for Solving the Problems] A cylinder device of the present invention is a cylinder tube that accommodates a piston provided with a piston rod so as to be slidable in the axial direction, and a piston rod attached to the cylinder tube so that the piston rod is slidable. A cylinder device having a supporting rod cover, the bearing being mounted on the rod cover and slidably guiding the piston rod, and an outer side formed on the rod cover axially outside and inside the bearing. A U-shaped packing mounted in the annular groove and the inner annular groove with the opening facing the bearing, and a fluid pressure formed on the opening side of the packing mounted in the outer annular groove. Provided in an air pressure communication pipe that communicates the chamber with the cylinder chamber in the cylinder tube, and allows the flow of air from the cylinder chamber to the fluid pressure chamber. And a check valve for blocking the flow in the reverse direction.

Also, the cylinder device of the present invention is characterized in that a throttle valve is provided in a bypass conduit for bypassing the check valve and guiding air.

[Operation] Since annular grooves are formed on the outer side and the inner side in the axial direction of the bearing so as to surround the bearing, and U-shaped packings are attached to the annular grooves with the openings facing the bearing,
The leakage or scattering of the lubricant from the rod penetrating portion of this bearing is prevented.

Compressed air in the cylinder chamber will be introduced into the fluid pressure chamber formed by each packing, and the packing will be expanded by the introduced air to increase the sealing force, and when compressed air is supplied into the cylinder chamber. In addition, since the air pressure also acts in the fluid pressure chamber, the surface contact pressure of the packing with respect to the piston rod does not change rapidly, and the durability of the packing is improved.

In particular, by providing a bypass conduit having a throttle valve, the air in the fluid pressure chamber is gradually discharged when the compressed air in the cylinder chamber is discharged, so the packing maintains a stable posture and seals. Will improve the sex.

[Embodiment 1] FIG. 1 is a sectional view showing a cylinder device according to an embodiment of the present invention.

The cylinder device of this embodiment is a double-acting air cylinder device, and both ends of the cylinder tube 1 are closed by a rod cover 2 and a head cover (not shown).

The inside of the cylinder tube 1 is partitioned into a left cylinder chamber 1a and a right cylinder chamber (not shown) by a piston 3 housed so as to be movable along the axial direction.

The rod cover 2 has an outer peripheral surface provided with a supply / discharge port 2a communicating with the left cylinder chamber 1a, and an outer peripheral surface of the head cover (not shown) communicating with a right cylinder chamber (not shown). The supply / discharge port (not shown) is opened.

A piston rod 4 is projected from one end surface of the piston 3, and the piston rod 4 movably penetrates a piston rod penetrating portion 5 of the rod cover 2 and is projected to the outside.

A bearing 6 impregnated with a lubricant is provided in the middle of the piston rod penetrating portion 5.

A pair of annular grooves 5a, 5b for mounting packing are provided on the outer side and the inner side of the bearing 6 in the circumferential direction, respectively.
U-shaped packings, that is, seal members 7a and 7b made of an elastic material such as rubber or synthetic resin are mounted in the respective annular grooves 5a and 5b.

The packings 7a, 7b are arranged in the annular grooves 5a, 5b so that their respective lip portions, that is, the opening portions are directed toward the bearing 6 and face each other at a predetermined interval.

Then, in the piston rod penetrating portion 5 between the packings 7a, 7b, sealed fluid pressure chambers 8a, 8b are formed.

The fluid pressure chamber 8a formed on the opening side of the packing 7a mounted in the outer annular groove 5a has a pneumatic conduction pipe in the left cylinder chamber 1a.
The air pressure communication pipe 10 is connected to the check valve 9.

The check valve 9 is provided so as to allow the flow of air from the cylinder chamber 1a to the fluid pressure chamber 8a and prevent the flow of fluid pressure from the fluid pressure chamber 8a side to the left cylinder chamber 1a side.

Next, the operation of this embodiment will be described.

First, when compressed air is supplied to a supply / discharge port (not shown) communicating with the right cylinder chamber (not shown), the piston 3 and the piston rod 4 are moved to the left side in FIG.

Then, when fluid pressure is supplied to the left cylinder chamber 1a through the supply / discharge port 2a, the piston 3 moved to the left side in FIG.
And the piston rod 4 is moved to the right side in the figure.

The cylinder device of the present embodiment is operated in this manner, but in this case, a part of the fluid pressure on the left cylinder chamber 1a side flows into the fluid pressure chamber 8a through the check valve 9 and By blocking the outflow of the fluid pressure of the pressure chamber 8a to the left cylinder chamber 1a, the fluid pressure chamber 8a is pressurized. The compressed air flowing into the fluid pressure chamber 8 is also supplied to the fluid pressure chamber 8b through the gap between the piston rod 4 and the bearing 6.

Further, when the air pressure in the fluid pressure chambers 8a, 8b drops due to air leakage, etc., a part of the fluid pressure in the left cylinder chamber 1a becomes a check valve until the fluid pressure chambers 8a, 8b become a constant pressure. The fluid pressure chambers 8a and 8b are flown into the respective fluid pressure chambers 9 through 9.

When compressed air is supplied into the fluid pressure chambers 8a and 8b in this manner, the packings 7a and 7b are spread out, and the packings 7a and 7b are removed with the piston rod 4 having an appropriate tightening margin. Since the pressing force is applied, the sealing force is increased and the leakage of the lubricant from the piston rod penetrating portion 5 of the bearing 6 is prevented.

The surface contact pressures of the packings 7a, 7b with respect to the piston rod 4 do not abruptly change due to the air pressures in the fluid pressure chambers 8a, 8b, and the surface contact pressures are stabilized, so that each packing 7a, The sealing property of 7b is stabilized, and the durability can be improved.

Further, by stabilizing the sealing property of the packings 7a, 7b and improving the durability, it is possible to reliably prevent the lubricant from splashing from the piston rod penetrating portion 5. Therefore, it is possible to prevent the lubricant from splashing. Pollution prevention and piston rod 4 and bearing 6
And the like can be improved.

[Embodiment 2] FIG. 2 is a sectional view showing a cylinder device according to another embodiment of the present invention.

In the second embodiment, a bypass conduit 11 is connected in parallel to the pneumatic conduit 10 in the first embodiment, and the bypass conduit 11 is provided with a throttle valve 12.

In the second embodiment, when the air pressure in the left cylinder chamber 1a is discharged from the supply / discharge port 2a, the fluid pressure chambers 8a, 8b
The compressed air therein is throttled by the throttle valve 12 and gradually discharged.

Therefore, when the air pressure is exhausted from the supply / exhaust port 2a, the compressed air is gradually discharged from the fluid pressure chambers 8a, 8b by the action of the throttle valve 12, so that the packing 7a, compared with the case of rapidly exhausting the air. The posture of 7b, that is, the sitting state is always stabilized, and it is possible to improve the sealing property and the durability.

Although the present invention has been specifically described based on the embodiments, the present invention is not limited to the first and second embodiments, and various modifications can be made without departing from the scope of the invention.

For example, in the cylinder device of the first and second embodiments,
Although two packings 7a and 7b are provided, the present invention may have a structure in which three or more packings are provided.

In the cylinder device of the first and second embodiments, the check valve 9 and the throttle valve 12 are provided outside the cylinder body.
Alternatively, the throttle valve 12 and the throttle valve 12 may be integrated in the cylinder body.

[Effects of the Invention] According to the structure of the cylinder device of the present invention, the following effects can be obtained respectively.

(1). U-shaped packings are installed in the outer annular groove formed on the outer side in the axial direction of the bearing and the inner annular groove formed on the inner side in the axial direction with the openings facing the bearing, and are installed in the outer annular groove. The pneumatic conduit formed on the opening side of the packing that connects the fluid pressure chamber to the cylinder chamber allows the flow of air from the cylinder chamber to the fluid pressure chamber and prevents the flow in the opposite direction. Since the valve is provided, by spreading the packing with the fluid in the fluid pressure chamber, it is possible to reliably seal the leakage of the lubricant leaking from the bearing.

(2). Also, since air pressure acts on the packing in the direction to spread it, even if the fluid in the cylinder chamber acts on the packing, the surface contact pressure of the packing with respect to the piston rod does not change rapidly, and the durability of the packing is improved. Can be improved.

(3). Since the fluid pressure chamber in the outer annular groove and the cylinder chamber are connected by a pneumatic conduit, the compressed air in the cylinder chamber is first guided into this fluid pressure chamber, so that lubrication from the bearing to the outside of the cylinder device is performed. The dispersion of the agent can be reliably sealed.

(4). By providing a throttle valve on the bypass conduit, the air in the fluid pressure chamber is gradually exhausted,
When exhausting the compressed air in the fluid pressure chamber, the sitting or posture of the packing can be maintained, and the sealability and the durability of the packing can be improved.

(5). Further, it is possible to reliably prevent contamination due to scattering of the lubricant and the like.

(6). Further, the reliability of the cylinder device can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a cylinder device which is an embodiment of the present invention, and FIG. 2 is a sectional view showing a cylinder device which is another embodiment of the present invention. 1 ... Cylinder tube, 1a ... Left side cylinder chamber, 2 ...
… Rod cover, 2a …… Supply / exhaust port, 3 …… Piston,
4 ... Piston rod, 5 ... Piston rod penetration,
5a …… outer annular groove, 5b …… inner annular groove, 6 …… bearing, 7
a, 7b …… Packing, 8a, 8b …… Fluid pressure chamber, 9 …… Check valve, 10 …… Pneumatic conduit, 11 …… Bypass conduit, 12 ……
Throttle valve.

Claims (2)

[Scope of utility model registration request] 1. A cylinder device having a cylinder tube for accommodating a piston provided with a piston rod slidably in an axial direction, and a rod cover attached to the cylinder tube for slidably supporting the piston rod. A bearing mounted on the rod cover to slidably guide the piston rod, and an outer annular groove and an inner annular groove formed on the rod cover axially outside and inside the bearing, respectively. A U-shaped packing mounted to the bearing with the opening facing, a fluid pressure chamber formed on the opening side of the packing mounted in the outer annular groove, and a cylinder chamber in the cylinder tube. A check valve which is provided in the communicating air pressure communication pipe and allows the flow of air from the cylinder chamber to the fluid pressure chamber and blocks the flow in the opposite direction. Cylinder and wherein the door. 2. A throttle valve is provided in a bypass conduit for bypassing the check valve and guiding air.
The cylinder device described.