JP2002213408A - Pneumatic actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a pneumatic actuator, and to shorten the assembling time of the pneumatic actuator. SOLUTION: An elastically deformable claw part 10 is formed on an outer peripheral part of a rod cap 9 and engaged with a groove part formed on a cylinder hole 6 formed inside of the actuator body 1, to make the rod cap 9 engage to the cylinder hole 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pneumatic actuator for converting the energy of compressed air into a linear motion of an operating member.

[0002]

2. Description of the Related Art A pneumatic actuator is a device for converting the energy of compressed air into a mechanical motion, and is used for moving a work and for operating a jig for holding or processing the work. Such a pneumatic actuator accommodates a piston having a piston rod attached slidably in an axial direction inside a cylinder chamber formed in an actuator body, and supplies and discharges compressed air before and after the piston. The piston rod reciprocates linearly.

[0003] Among such pneumatic actuators, ultra-small pneumatic actuators have been developed in order to facilitate arrangement around jigs where installation space is limited.
In this case, the cylinder chamber is defined by closing the open end of the bottomed hole formed in the actuator body with a rod cap.

[0004]

In a conventional pneumatic actuator, a rod cap is fixed to a cylinder chamber by a snap ring. But,
In an ultra-small pneumatic actuator, a certain size is required for the snap ring in order to secure the strength for fixing the rod cap, which hinders downsizing of the pneumatic actuator. Further, when assembling the pneumatic actuator, there is a problem that it takes a long time to assemble the snap ring because it is not easy to handle a small and thin snap ring, and the snap ring may be plastically deformed at the time of assembly.

A method of attaching the rod cap to the actuator body by screw connection has also been performed. However, in this method, it is necessary to provide a thread on the actuator body, so that the actuator body becomes thick, and the pneumatic actuator has a large thickness. There is a disadvantage that the external dimensions are increased.

An object of the present invention is to reduce the size of a pneumatic actuator.

Another object of the present invention is to reduce the assembly time of a pneumatic actuator.

[0008]

A pneumatic actuator according to the present invention is a pneumatic actuator which converts the energy of compressed air into a linear motion of an operating member and outputs the same, wherein the operating member is slidably accommodated in the axial direction. An actuator body having a cylindrical cylinder hole, a ring-shaped groove formed on an inner peripheral surface of the cylinder hole, a closing member provided in the cylinder hole to close the cylinder hole, and the closing member And a claw portion which is provided on the outer peripheral portion and is elastically deformable in a radial direction, and the closing member is fixed in the cylinder hole by engaging the claw portion and the groove portion. Features.

In the pneumatic actuator of the present invention, the cylinder hole may be a bottomed hole.

In the pneumatic actuator of the present invention, a plurality of the closing members may be fixed in the cylinder hole, and a sealing member may be arranged between the plurality of closing members.

In the present invention, the rod cap is fixed by engaging the claw portion provided on the rod cap with the groove provided in the cylinder hole, so that the pneumatic actuator can be downsized. Can be.
Further, since the rod cap is fixed by being pushed into the cylinder hole, the assembling time of the pneumatic actuator can be reduced.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view showing a pneumatic actuator according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing an AA cross section of the pneumatic actuator shown in FIG.

The pneumatic actuator shown in FIG. 1 is a very small one having a cylinder diameter of about φ4.5 to φ6.0, and can be easily arranged around a jig or the like where a mounting space is restricted. ing.

[0015] As shown in FIG.
Are end faces 1a from which the piston rod 2 projects, mounting faces 1b and 1c provided with four mounting holes 3, and side faces 1d and 1e.
And is formed in a thin rectangular parallelepiped shape as a whole.

When the pneumatic actuator is mounted on a jig or the like (not shown), at least one of the mounting surfaces 1b and 1c is brought into contact with a jig or the like (not shown) and fixed by a fastening member through the mounting hole 3. I do. The side surface 1d is provided with supply / discharge ports 4 and 5 to which pipes for supplying / discharging compressed air from a working fluid supply source (not shown) are attached.

As shown in FIG. 2, the actuator body 1
Is formed with a cylinder hole 6 as a hole with a bottom. The cylinder hole 6 is a boundary between a large-diameter inner peripheral surface 6a, a small-diameter inner peripheral surface 6b, and these inner peripheral surfaces 6a, 6b. It has a stepped portion 6c and a ring-shaped groove 7 formed on the inner peripheral surface 6a. The groove 7 has an inner peripheral surface 7a whose inner diameter is slightly larger than the inner peripheral surface 6a, and a cylinder hole 6 formed in the inner peripheral surface 7a.
And a tapered surface 7b provided at a position facing the hooking surface 7b with the inner peripheral surface 7a interposed therebetween.
c.

In order to close the open end of the cylinder hole 6,
A metal stopper 8 having an outer diameter substantially equal to the inner diameter of the inner peripheral surface 6a and a resin rod cap 9 as a closing member are fitted in the cylinder hole 6.
The material of the rod cap 9 is not limited to resin, but may be any other material as long as it is elastically deformable.

A locking surface 10 is provided on the outer periphery of the rod cap 9.
a and elastically deformable claw 10 having a tapered surface 10b
The outer diameter of the claw portion 10 is larger than the inner diameter of the inner peripheral surface 6a, and is formed to have substantially the same size as the inner peripheral surface 7a of the groove portion 7. When the rod cap 9 is pushed into the cylinder hole 6, the claw portion 10 has the tapered surface 10 b
When pressed against the inner peripheral surface 6a of the cylinder hole 6, the elastic member is elastically deformed in a direction to reduce its outer diameter and is inserted into the cylinder hole 6. Claw part 1
When 0 reaches the position of the groove 7, the claw 10 is elastically deformed so as to return its outer diameter to the original diameter and engages with the groove 7. At this time, since the locking surface 10a is engaged with the hooking surface 7b of the groove 7, the rod cap 9 is
It does not get out of the way. The stopper 8 has one end surface in contact with the stepped portion 6c and the other end in contact with the rod cap 9, so that the stopper 8 and the rod cap 9 are separated from the cylinder hole 6 by the hooking surface 7b and the stepped portion 6c. And will be fixed in the axial direction. Therefore, the inner peripheral surface 6a of the cylinder hole 6 is different from the conventional pneumatic actuator.
Since the rod cap 9 can be fixed without providing a thread on the rod or using a small thin snap ring, the pneumatic actuator can be downsized, and the assembling time of the fluid pressure actuator can be reduced. can do.

The inside of the cylinder hole 6 closed by the stopper 8 and the rod cap 9 forms a cylinder chamber 11, and an operation member slidably moves in the axial direction of the inner peripheral surface 6 b of the cylinder chamber 11. The piston 12 is accommodated. The interior of the cylinder chamber 11 contains the piston 12
Is divided into two pressure chambers 11a and 11b by
Each of the pressure chambers 11a and 11b is connected to a working fluid supply source (not shown) through supply and discharge ports 4 and 5. By supplying compressed air to the pressure chambers 11a and 11b from the supply / discharge ports 4 and 5, the piston 12 is moved to the cylinder chamber 11
It is designed to reciprocate straight inside. A piston rod 2 is fixed to the piston 12, and the piston rod 2 is connected to the outside through stoppers 8 and through holes 8a and 9a formed in a rod cap 9, respectively, so that the movement of the piston 12 is controlled by the outside. It can be output as work to. Reference numeral 12a is a piston packing.

A rod packing 14 is provided in a cavity 13 defined between the stopper 8 and the rod cap 9.
Is provided. The rod packing 14 comes into contact with the outer peripheral surface of the piston rod 2 and the wall surface inside the hollow portion 13 so as to prevent the compressed air from leaking to the outside from the through holes 8a and 9a. An O-ring 15 is provided on the outer periphery of the rod cap 9 so as to prevent the compressed air from leaking to the outside from between the inner peripheral surface 6a of the cylinder hole 6 and the rod cap 9.

By adopting such a structure, the inner peripheral surface 6 of the cylinder hole 6 is formed like a conventional pneumatic actuator.
It is not necessary to provide a thread on a, or to fix the rod cap 9 using a small and thin snap ring, and to form the groove portion 7 having an inner diameter slightly larger than the inner peripheral surface 6a in the inner peripheral surface 6a of the cylinder hole 6. Therefore, the size of the pneumatic actuator can be reduced. Further, since the rod cap 9 can be fixed to the cylinder hole 6 only by the operation of pushing the rod cap 9 into the cylinder hole 6, the assembling time can be reduced.

FIG. 3 is a perspective view showing a modification of the pneumatic actuator shown in FIG. 1, in which two rod caps are fitted into a cylinder hole with a rod packing interposed therebetween, and FIG. It is sectional drawing which shows the AA cross section of the pneumatic actuator shown in FIG.

As shown in FIG. 3, the actuator body 2
Reference numeral 0 denotes an end face 20a from which the piston rod projects, three side faces 20b, 20c, and 20d, and four mounting holes 2 for mounting the pneumatic actuator to a jig (not shown).
3 is provided on the mounting surface 20e. Side 20
b, 20c, and 20d with supply / discharge ports 21, 21, respectively.
2 are provided so that any of the supply / discharge ports can be selectively used. Unused supply / discharge ports are closed by plugs. The sensor mounting groove 20 is located between the respective side surfaces.
f, 20 g are provided in the sensor mounting groove 20.
By attaching a sensor to f and 20g, the stroke end of this pneumatic actuator can be detected.

As shown in FIG. 4, the actuator body 2
A cylinder hole 24 as a hole with a bottom is formed inside 0, and grooves 25 and 26 are formed in the inner peripheral surface 24a of the cylinder hole 24. These grooves 25, 26
Are located at the inner peripheral surfaces 25a and 26a, each having an inner diameter slightly larger than the inner peripheral surface 24a, and at the ends of the inner peripheral surfaces 25a and 26a on the opening end side of the cylinder hole 24 and perpendicular to the axial direction of the cylinder hole 24. Hook surfaces 25b, 26b formed in the direction
And tapered surfaces 25c and 26c provided at positions facing the hooking surfaces 25b and 26b with the inner peripheral surface 24a interposed therebetween.

In order to close the cylinder hole 24, two resin-made rod caps 27 and 28 as closing members each having an outer diameter substantially equal to the inner peripheral surface 24a are fitted into the cylinder hole 24. Have been. Locking surfaces 29a, 30a are provided on the outer peripheral portions of the respective rod caps 27, 28.
Elastically deformable claws 29 and 30 having a taper surface 29b and a taper surface 30b. The outer diameter of the claws 29 and 30 is larger than the inner diameter of the inner peripheral surface 24, and is substantially the same as the grooves 25 and 26. It is formed in dimensions. These claws 29, 30
The rod caps 27 and 28 are fixed inside the cylinder hole 24 by engaging the grooves with the grooves 25 and 26, respectively.

The inside of the cylinder hole 24 closed by the rod caps 27, 28 is a cylinder chamber 31, and the inside of the cylinder chamber 31 has an inner peripheral surface 24a.
A piston 32 is provided so as to be slidable in the axial direction.
The interior of the cylinder chamber 31 is divided into two pressure chambers 31a and 31b by the piston 32. The respective pressure chambers 31a and 31b are connected to a working fluid supply source (not shown) via supply / discharge ports 21 and 22. ing. By supplying compressed air from the supply / discharge ports 21 and 22 to the pressure chambers 31a and 31b, the piston 32 linearly reciprocates in the cylinder chamber 31. A piston rod 33 is fixed to the piston 32. The piston rod 33 is connected to the outside through through holes 27a and 28a formed in the rod caps 27 and 28, and controls the movement of the piston 32 to the outside. It can be output as work. A magnet 35 supported by a support 34 is attached to the piston 32, and sensors attached to the sensor attachment grooves 20f and 20g detect the position of the stroke end in response to the magnetic field of the magnet 35. It has become. 32
a is a piston packing.

A rod packing 37 as a sealing member is provided inside a cavity 36 defined between the rod caps 27 and 28. The rod packing 37 is in contact with the outer peripheral surface of the piston rod 33 and the inner peripheral surface 24a of the cylinder hole 24 to prevent the compressed air from leaking to the outside.

Since the hollow portion 36 provided with the rod packing 37 is formed between the two independently fixed rod caps 27 and 28, the outer periphery of the rod packing 37 receives the thrust of the piston 32. Therefore, it is not necessary to provide a supporting member, so that the diameter of the cylinder hole can be made smaller, so that the pneumatic actuator can be made smaller.

FIG. 5 is a sectional view showing a modified example of the pneumatic actuator shown in FIG. 3, in which a dust collecting function is added.

The basic structure of the pneumatic actuator shown in FIG. 5 is substantially the same as that of the pneumatic actuator shown in FIG. 3, but in this modification, a dust collecting function for removing foreign matter generated from the rod packing is added. .

When the pneumatic actuator is operated, the piston rod slides on the rod packing and the rod cover and wears. The foreign matter generated at this time adheres to the piston rod, is exposed to the outside air, and is scattered. Therefore, when the pneumatic actuator is used in a clean room, it is necessary to provide a dust collecting function.

In a cylinder hole 41 formed in the actuator body 40 of the pneumatic actuator, three rod caps 42, 43, and 44 are provided with respective claw portions 42.
a, 43a, and 44a are engaged with and fixed to the grooves 41a, 41b, and 41c provided in the cylinder hole 41, and are fitted into hollow portions 45 and 46 provided between the rod caps 42, 43, and 44, respectively. Is provided with two rod packings 47 and 48 as seal members.

The rod packing 47 disposed inside is disposed so as to be in contact with the outer peripheral surface of the piston rod 33 and the inner peripheral surface of the cylinder hole 41 as in the case shown in FIG. The compressed air is prevented from leaking to the outside.

On the other hand, the rod packing 48 disposed outside collects foreign matter adhering to the piston rod 33. Negative pressure is supplied to a dust collecting port 49 which is located between the rod packings 47 and 48 and opened, and foreign matter collected by the rod packing 48 is removed by the negative pressure. Is sucked out and discharged out of the clean room.

The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention. For example, in the present embodiment, the pneumatic actuator is a double-acting single-rod cylinder, but is not limited thereto.
The invention may be applied to any pneumatic actuator such as a rack and pinion type oscillating actuator as disclosed in Japanese Patent Application Laid-Open No. 29506/29.

[0037]

According to the present invention, the rod cap is fixed by engaging the claw provided on the rod cap with the groove provided in the cylinder hole, so that the pneumatic actuator can be downsized. be able to.
Further, since the rod cap is fixed by being pushed into the cylinder hole, the assembling time of the pneumatic actuator can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a pneumatic actuator according to an embodiment of the present invention.

FIG. 2 is a sectional view showing an AA section of the pneumatic actuator shown in FIG. 1;

FIG. 3 is a perspective view showing a modified example of the pneumatic actuator shown in FIG. 1, in which two rod caps are fitted into a cylinder hole with a rod packing interposed therebetween.

FIG. 4 is a sectional view showing an AA section of the pneumatic actuator shown in FIG. 3;

FIG. 5 is a modified example of the pneumatic actuator shown in FIG. 3, and is a cross-sectional view showing a case where a dust collecting function is added.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Actuator main body 1a End surface 1b, 1c Mounting surface 1d, 1e Side surface 2 Piston rod 3 Mounting hole 4, 5 Supply / discharge port 6 Cylinder hole 6a, 6b Inner peripheral surface 6c Step 7 Groove 7a Inner peripheral surface 7b Hook surface 7c Tapered surface Reference Signs List 8 Stopper 8a, 9a Through hole 9 Rod cap 10 Claw 10a Locking surface 10b Tapered surface 11 Cylinder chamber 12 Piston 12a Piston packing 11a, 11b Pressure chamber 13 Cavity 14 Rod packing 15 O-ring 20 Actuator body 20a End face 20b, 20c , 20d Side surface 20e Mounting surface 20f, 20g Sensor mounting groove 21, 22 Supply / discharge port 23 Mounting hole 24 Cylinder hole 24a Inner peripheral surface 25, 26 Groove 25a, 26a Inner peripheral surface 25b, 26b Hook surface 25c, 26c Tapered surface 27, 28 Rodki Top 27a, 28a Through-hole 29, 30 Claw 29a, 30a Locking surface 29b, 30b Tapered surface 31 Cylinder chamber 31a, 31b Pressure chamber 32 Piston 32a Piston packing 33 Piston rod 34 Support 35 Magnet 36 Cavity part 37 Rod packing 40 Actuator main body 41 Cylinder hole 41a, 41b, 41c Groove 42, 43, 44 Rod cap 42a, 43a, 44a Claw 45, 46 Cavity 47, 48 Rod packing 49 Dust collection port

Claims (3)

[Claims] 1. A pneumatic actuator for converting the energy of compressed air into linear motion of an operating member and outputting the same, comprising: an actuator main body having a cylindrical cylinder hole for slidably housing the operating member in an axial direction; A ring-shaped groove formed on an inner peripheral surface of the cylinder hole; a closing member provided in the cylinder hole to close the cylinder hole; and a radially elastic member provided on an outer peripheral portion of the closing member. A pneumatic actuator having a deformable claw, wherein the claw is engaged with the groove to fix the closing member in the cylinder hole. 2. The pneumatic actuator according to claim 1, wherein said cylinder hole is a bottomed hole. 3. The pneumatic actuator according to claim 1, wherein a plurality of the closing members are fixed in the cylinder hole, and a sealing member is arranged between the plurality of closing members. Pneumatic actuator.