JPS63225707A - Pneumatic actuator - Google Patents

Abstract

PURPOSE:To improve the durability of a pneumatic actuator by forming it with an elastic body part made of rubber and a coiled spring. CONSTITUTION:The bellows body part 2 of a pneumatic actuator 1 whose contacted part is spirally shaped, is formed of a flexible thin film layer made of rubber or synthetic resin. A coil spring 7 for recovery, whose both ends are fixed to end members 3, 4, is joined with the contacted part of the bellows body part 2 in conformity with its spiral form. When air is fed under pressure from an air supply port 6 so that the bellows body part 2 is extended, the radial expansion is prevented by means of the coil spring 7, and thereby only the longitudinal extension is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a pneumatic actuator that can withstand relatively large changes in internal pressure and can flexibly expand and contract while maintaining a regular bellows waveform. .

<Conventional Example and Problems> In general, bellows manufactured from a flexible material such as rubber has a corrugated body portion with a constant thickness, and has elasticity in the direction of its central axis.

However, when using this elasticity as an air actuator for reciprocally operating a predetermined device in a clean room, for example, it is necessary to close both ends of the body and expand and contract in a sealed state. At this time, since the internal fluid pressure changes, it is not possible to expand and contract with an ideal torso waveform, that is, a uniform waveform, and irregularly bent portions often occur in the torso.

If expansion and contraction are repeated in such a state, material fatigue will progress in the irregularly bent portions, resulting in a significant decrease in durability.

Further, since internal pressure is applied to the bellows body in a sealed state, the flexible body expands in the outer circumferential direction, making it impossible to obtain a predetermined operating stroke and operating force.

Means for Solving the Problems> The present invention was proposed to eliminate the above-mentioned drawbacks, and its purpose is to ensure that the waveform of the body that expands and contracts while being sealed is always uniform and regular. A pneumatic actuator that uses a single coil spring to maintain the shape of the bellows, and to quickly and reliably contract and return the bellows body to its original position when the air pressure is set to degassing mode. It is about providing.

Another object of the present invention is to provide a pneumatic actuator that has a flexible bellows body and can provide a predetermined length of actuation stroke and actuation force.

Therefore, the object of the present invention is to provide an elastic body formed into a spiral bellows by a thin film layer of rubber or synthetic resin, and an elastic body that is attached or detached so as to correspond to the corrugated peaks and/or troughs of the body. a coiled return spring that is fixed in place;
and end members airtightly fixed to both ends of the body.

<Example> Next, the present invention was carried out according to the example shown in FIGS.
This will be explained in more detail.

FIG. 1 shows the pneumatic actuator (1) according to the present invention when it is contracted, that is, in a degassing mode. (2
) is a bellows body with a spiral constriction,
It is made of a flexible thin film layer made of rubber or synthetic resin.

(]) and (4) are end members airtightly fixed to both ends of the bellows body (2), and one end member (3) is provided with a connecting part (5) to a workpiece, etc. There is. Further, as shown in FIG. 3, the other end member (4) is provided with an air supply port for connection to a supply mechanism (not shown) such as a compressor.

(7) is a return coil spring, which is arranged in close contact with the spiral shape of the constriction of the bellows body (2), and its both ends are fixed to the end members (3) and (4). has been done.

By setting the pitch of this coil spring (7), both end members (3) (
4) can be held at arbitrary intervals.

FIG. 2.3 shows a state in which the bellows body (2) is expanded by feeding air under pressure from the air supply port (6). At this time, the bellows body (2) receives internal pressure in the diametrical direction and tries to expand in the radial direction, but the coil spring (7)
) or 1 to stretch while holding the outer circumference of the feed section (2).
The expansion is prevented, and only expansion in the vertical axis direction occurs while maintaining a uniform and regular bellows waveform.

On the other hand, when air is supplied from the air supply port (6) to decompression mode, the bellow body (2) is quickly returned to its original position as shown in Fig. 1 by the return force of the coil spring (7). .

Therefore, the coil spring (7) has two functions: reinforcing the internal pressure in the radial direction and maintaining a regular waveform throughout the expansion and contraction of the bellows body (2), and restoring the function when the internal pressure decreases. be.

Another embodiment is shown in FIG.

(81) to (84) are shaft members constituting the sliding telescoping shaft (8), including the shaft member (old) and the shaft member (8).
4) are fixed to the opposing surfaces of the end member (4) and the end member (3), respectively. Therefore, even if the actuator is installed horizontally, for example, the actuator (1) will not shift in the direction of expansion and contraction due to the bending of the bellows body (2), and will be guided by the telescoping shaft (8) and centered. It is axially right and can reliably expand and contract.

The material of the bellows body (2) used here is preferably one manufactured according to the following example.

That is, a core mold with smooth spiral irregularities on the outer peripheral surface is prepared, and the core mold is immersed in a rubber liquid tank such as a latex rubber liquid of a predetermined concentration or a synthetic resin liquid tank (not shown) and then pulled up. A thin film layer is applied and formed. Before this thin film layer dries, the vicinity of its upper end is cleaned and removed by a small width.

Next, the second thin film layer is integrally laminated on the outside of the first thin film layer by reversing the steps from the above-mentioned dipping step to the washing treatment step. In addition, if necessary, repeat this process further to integrally laminate thin film layers on the outside until the desired thickness is achieved, and finally remove the core material to obtain the bellows body (2). It is.

The wall thickness of the bellows body (2) manufactured in this way is:
It varies depending on the concentration of the coating liquid and the pulling speed of the core mold, but
The thickness of each layer can be adjusted to several microns. Therefore, even when forming an extremely thin and flexible bellows body, it is possible to form a bellows body (2) with high bending strength by forming several to several tens of layers.

Note that it is also an embodiment included in the present invention to form the necessary thickness of the body by performing the dipping step only once.

The bellows body (2) has a thin wall thickness, so it has excellent bending flexibility, and at the same time, it does not contain foreign substances such as carbon, so it has partial strength and uniformity.

Alternatively, the strength against internal pressure may be increased by performing the dipping step with fibers or nonwoven fabric laminated between a plurality of rubber layers.

The end member (
3) Effects of assembling (4) into the actuator (1) by airtightly fixing it with adhesive or the like> According to the pneumatic actuator of the present invention, the waveform of the bellows body that expands and contracts while being sealed is Since it can always maintain a uniform and regular shape, there is no concern about local material deterioration due to the occurrence of irregularly bent parts, and it is highly durable.

Although the bellows body is flexible, it has a predetermined operating stroke and operating force.

Furthermore, when the air pressure is set to the degassing mode, the bellows body can quickly and reliably contract to its original position and return to its original position.

Since the internal air is not released to the outside of the bellows JU, it is ideal as an actuator for reciprocally operating equipment in a place where strict dust regulations are required, such as a clean room.

Furthermore, since the manufacturing process for the bellows body is a multi-layer integral film formation using the repeated dipping method using the core mold as in the example, pinholes can be completely prevented and the assembly process can be simplified. It can be manufactured easily and at low cost.

[Brief explanation of drawings]

1 to 2 are front views showing one embodiment of the pneumatic actuator according to the present invention, FIG. 3 is a central vertical sectional view in FIG. 2, and FIG. 4 is a central longitudinal sectional view showing another embodiment. Figure. (1)---actuator, (2)---one bellow body, (3)---one end member, (4)---one end member, (6)---one air supply port, (7 ) -m-Returning spring, (8)----1 Telescopic shaft.

Claims (1)

[Scope of Claims] An elastic body made of rubber or synthetic resin in the form of a spiral bellows, and a coil-shaped elastic body that is tightly or removably fixed to match the corrugated peaks and/or troughs of the body. A pneumatic actuator comprising: a return spring; and end members airtightly fixed to both ends of the body. 2. The pneumatic actuator according to claim 1, wherein an extensible core shaft is interposed and fixed between the facing end members.