JPH0742576A - Single-acting hydraulic cylinder device - Google Patents

Abstract

PURPOSE:To eliminate a need to form an air vent hole in a body so as to prevent entrance of a foreign matter to the inside of the body. CONSTITUTION:When pressure fluid is fed to a high pressure chamber 12 and a communication hole 18 is closed by a reed valve (on-off valve) 19, a piston 7 is moved toward a low pressure chamber 11. When the feed of pressure fluid to a high pressure chamber 12 is stopped, the reed valve 19 is restored to open the communication hole 18, whereby low and high pressure chambers 11 and 12 are intercommunicated and simultaneously the piston 7 is moved toward the high pressure chamber 12. In this case, fluid (air) flows from the high pressure chamber 12 side to the low pressure chamber 11 through the communication hole 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-acting fluid pressure cylinder device such as an air cylinder for operating an exhaust shutter of a vehicle.

[0002]

2. Description of the Related Art In a single-acting air cylinder device, a piston housed in a body is moved toward the other low-pressure chamber by supplying compressed air to one high-pressure chamber formed in the body. The structure is such that the piston rod that is integral with the piston moves back and forth.

In the air cylinder device having such a structure, an air vent hole communicating with the outside air is usually provided in the body on the low pressure chamber side, and the air is supplied to the low pressure chamber and the outside by a pump action when the piston reciprocates. It is allowed to freely flow between the pistons so that compression pressure or vacuum pressure does not act on the piston.

When the air vent hole is provided, when the air cylinder device is used outdoors such as an actuator for actuating an exhaust shutter of an automobile, where rain water and dust are liable to be environmentally affected, foreign matter such as rain water is prevented through the air vent hole. It may get inside the body. In order to prevent this, conventionally, a filter is provided in the air vent hole, or the surrounding of the air vent hole is
It was covered with a cover or the like having air holes communicating with the outside air.

[0005]

However, the above-mentioned filter and cover are not sufficient in preventing rainwater from entering the body, and rainwater and dust gradually enter the body during long-term use. To rust each part in the body,
This will accelerate wear of the sliding parts of the piston and reduce the durability and reliability.

The present invention has been made to solve the above problems, and by eliminating the air vent hole, it is possible to completely prevent foreign matter such as rainwater from entering the body. An object is to provide a fluid pressure cylinder device.

[0007]

In order to achieve the above object, the present invention provides a high-pressure piston in which a piston, to which a piston rod is fixed, is always formed on one side in a closed cylindrical body. A single action in which the piston is moved toward the low-pressure chamber formed on the other side by accommodating the high-pressure chamber so as to be reciprocally movable while being biased toward the chamber side and supplying the pressurized fluid to the high-pressure chamber. In the fluid hydraulic cylinder device, the piston is provided with a communication hole for communicating the high pressure chamber and the low pressure chamber, and an opening / closing valve for closing the communication hole when the pressure fluid is supplied to the high pressure chamber. It is a feature.

[Action]

When pressure fluid is supplied to the high pressure chamber and the on-off valve closes the communication hole, the piston moves a required stroke toward the low pressure chamber. When the supply of the pressure fluid to the high pressure chamber is stopped, the opening / closing valve opens the communication hole, whereby the high pressure chamber and the low pressure chamber communicate with each other, and at the same time, the piston moves toward the high pressure chamber side. At this time, since the fluid flows into the low pressure chamber from the high pressure chamber side through the communication hole, foreign matter does not enter the low pressure chamber from the outside.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, (1) is a cylindrical body having a side wall (1a) at the left end (hereinafter, the direction will be referred to in the drawings), and a bulging portion continuously provided inward at the center of the side wall (1a). A guide hole (2) is formed in (1b).

The opening on the right side of the body (1) has a disc-shaped closing plate (4) on a flange (3) provided outwardly on the right end of the body (1).
Are fixed by fixing with a plurality of bolts (5).

Reference numeral (6) is an air supply pipe for supplying compressed air into the body (1), which is screwed to the center of the closing plate (4).

A piston (7) is accommodated in the body (1) so as to be slidable in the left-right direction. A wear-resistant ring (8) and a rubber seal member (9) are fitted on the outer peripheral surface of the piston (7).

The piston (7) is constantly urged to the right by a compression coil spring (10) which is compressed between the left end surface and the side wall (1a), and normally, the piston (7) is Since the right end of the abutment plate contacts the closing plate (4), it is located at the right end. The left and right vacant chambers that sandwich the piston (7) in the body (1)
There are a low pressure chamber (11) and a high pressure chamber (12) respectively.

(13) is a body which penetrates the guide hole (2).
The piston rod extends in and out of (1), and its right base end is fixed to the piston (7) by a nut (14). The tip of the piston rod (13) is connected to a drive shaft (not shown) such as an exhaust shutter via a connecting piece (15).

Reference numeral (16) is a bush press-fitted into a recessed hole (17) formed at the left end of the side wall (1a), which is a piston rod (13).
By closely contacting the outer peripheral surface of the body 1, the airtightness of the inside and outside of the body (1) is maintained.

The low pressure chamber (11) and the high pressure chamber (1
A communication hole (18) that communicates with 2) is provided in the left-right direction. One end of a reed valve (open / close valve) (19) having a size capable of closing the communication hole (18) is fixed to the right side surface of the piston (7) adjacent to the right opening end of the communication hole (18). ing.

The reed valve (19) is made of a spring plate having a required plate thickness, and by bending it slightly outward (to the right), it is mounted so as to be separated from the communication hole (18) under normal conditions. Has been.

Thus, in the high pressure chamber (12), the air supply pipe
When compressed air with a predetermined pressure exceeding the spring load of the compression coil spring (10) is supplied from (6), the reed valve (19) is bent inward (leftward) as shown in FIG. Piston
Close the communication hole (18) by making close contact with the right end of (7). At the same time, the piston (7) moves to the left by a predetermined stroke of the piston rod (13) and stops.

At this time, the pressure in the low pressure chamber (11) is
As the (7) moves, it rises, which causes the reed valve (19).
May be difficult to close, but the piston rod
While setting the maximum extension stroke of (13) appropriately,
If the pressure of the compressed air supplied is high enough, the reed valve
(19) can be bent in the closing direction without any trouble.

When the supply of compressed air into the high pressure chamber (12) is stopped, the reed valve (19) immediately elastically restores to the outside to open the communication hole (18), as shown in FIG. Piston at the same time
(7) is a closing plate due to the biasing force of the compression coil spring (10).
Move to the right end where it touches (4).

At this time, the air in the high pressure chamber (12) flows into the communication hole (1
Since it flows into the low pressure chamber (11) through 8), the low pressure chamber (11) is prevented from becoming a negative pressure, and therefore the vacuum pressure does not act on the piston (7) to prevent its movement. .

As described above, in the cylinder device of the above embodiment, the piston (7) is provided with the communication hole (18) for communicating the low pressure chamber (11) with the high pressure chamber (12). Communication hole
Reed valve (19) operated by the pressure of compressed air (18)
The body (1)
A conventional air vent is provided in the body to let outside air into the body (1).
There is no need to circulate inside or outside of.

As a result, even if the cylinder device of the present invention is mounted as an actuator for driving an exhaust shutter, for example, on a portion where rainwater, dust, etc. are easily splashed, foreign matter such as rainwater will enter the body (1). Can be completely prevented, and the durability and reliability of the air cylinder device are significantly improved.

In the embodiment, the communication hole (18) and the reed valve (19) that opens and closes the communication hole are one, but a plurality of communication holes may be provided. Further, instead of the reed valve (19), for example, a check-ball type on-off valve that allows air flow only on the high pressure chamber (12) side may be provided in the communication hole (18).

[0025]

According to the present invention, when the piston moves from the low pressure chamber side to the high pressure chamber side, the fluid (air) is circulated in the body through the communication hole. Since it is not necessary to provide an air vent hole in the body, it is possible to completely prevent foreign matter such as rainwater and dust from entering the body, and the durability and reliability of the cylinder device are significantly improved.

[Brief description of drawings]

FIG. 1 is a central longitudinal side view showing a state before supplying a pressurized fluid according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of the main part when the pressure fluid is supplied.

[Explanation of symbols]

(1) Body (1a) Side wall (1b) Bulging part (2) Guide hole (3) Flange (4) Closure plate (6) Air supply pipe (7) Piston (8) Ring (9) Seal member (10) Compression coil spring (11) Low pressure chamber (12) High pressure chamber (13) Piston rod (16) Bushing (18) Communication hole (19) Reed valve (open / close valve)

Claims (1)

[Claims] 1. A piston having a piston rod fixed therein is housed in a closed cylindrical body so as to be capable of reciprocating while being constantly urged toward a high-pressure chamber formed on one side thereof. Then, in the single-acting fluid pressure cylinder device in which the piston is moved toward the low-pressure chamber formed on the other side by supplying the pressure fluid to the high-pressure chamber, the piston includes a high-pressure chamber and a low-pressure chamber. A single-acting fluid pressure cylinder device comprising a communication hole for communicating with the chamber and an opening / closing valve for closing the communication hole when a pressure fluid is supplied to the high pressure chamber.