JP4393719B2 - Pneumatic actuator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pneumatic actuator that converts energy of compressed air into linear motion of an actuating member.
[0002]
[Prior art]
The pneumatic actuator is a device that converts the energy of compressed air into a mechanical motion, and is used for moving a workpiece and operating a jig for holding or machining the workpiece. Such a pneumatic actuator accommodates a piston having a piston rod attached inside a cylinder chamber formed in the actuator body so as to be slidable in the axial direction, and supplies and discharges compressed air before and after the piston. The piston rod is reciprocated linearly.
[0003]
For such a pneumatic actuator, an ultra-small one has been developed to facilitate the arrangement around a jig whose mounting space is restricted. In this case, the cylinder chamber is formed in the actuator body. The opening end of the bottomed hole is closed and formed by a rod cap.
[0004]
[Problems to be solved by the invention]
In the conventional pneumatic actuator, the rod cap is fixed to the cylinder chamber by a snap ring. However, in an ultra-small pneumatic actuator, if a strength for fixing the rod cap is to be secured, the snap ring requires a certain size, which has been an obstacle to downsizing the pneumatic actuator. Further, when assembling the pneumatic actuator, there is a problem that it takes time to assemble because the snap ring is not easy to handle and the snap ring may be plastically deformed during assembly.
[0005]
Also, there is a method of attaching the rod cap by screwing to the actuator body. However, in this method, it is necessary to provide a thread on the actuator body. There was a drawback of becoming larger.
[0006]
An object of the present invention is to reduce the size of a pneumatic actuator.
[0007]
Another object of the present invention is to reduce the assembly time of the pneumatic actuator.
[0008]
[Means for Solving the Problems]
The pneumatic actuator of the present invention is a pneumatic actuator that converts the energy of compressed air into linear motion of an operating member and outputs it, and includes an actuator having a cylindrical cylinder hole that slidably accommodates the operating member in the axial direction. body and, a plurality of grooves formed in a ring shape on the inner peripheral surface of each of the cylinder bore, provided in each said cylinder bore, a plurality of the closing member for closing the cylinder bore, each of said closure member And a seal disposed between the plurality of closing members and a claw portion that is elastically deformable in the radial direction on the outer peripheral portion of the cylinder and engages with the groove portions to fix the closing member in the cylinder hole. And a member .
[0011]
In the present invention, since the rod cap is fixed by engaging the claw portion provided in the rod cap with the groove portion provided in the cylinder hole, the pneumatic actuator can be reduced in size. Further, since the rod cap is fixed by being pushed into the cylinder hole, the assembly time of the pneumatic actuator can be shortened.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0013]
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.
[0014]
The pneumatic actuator shown in FIG. 1 is an ultra-small one having a cylinder diameter of about φ4.5 to φ6.0, and is easily arranged around a jig where the mounting space is restricted.
[0015]
As shown in FIG. 1, the actuator body 1 has an end face 1a from which the piston rod 2 protrudes, mounting faces 1b and 1c provided with four mounting holes 3, and side faces 1d and 1e. It is formed in a thin rectangular parallelepiped shape.
[0016]
When the pneumatic actuator is attached to a jig or the like (not shown), at least one of the attachment surfaces 1b and 1c is brought into contact with the jig or the like (not shown) and fixed by a fastening member through the attachment hole 3. The side surface 1d is provided with supply / discharge ports 4 and 5 to which piping for supplying and discharging compressed air from a working fluid supply source (not shown) is attached.
[0017]
As shown in FIG. 2, a cylinder hole 6 as a bottomed hole is formed inside the actuator body 1, and the cylinder hole 6 has a large-diameter inner peripheral surface 6a, a small-diameter inner peripheral surface 6b, and these It has a stepped portion 6c that is a boundary between the inner peripheral surfaces 6a and 6b, and a ring-shaped groove portion 7 formed in the inner peripheral surface 6a. The groove portion 7 is formed in an inner peripheral surface 7a whose inner diameter is slightly larger than the inner peripheral surface 6a, and on the opening end side of the cylinder hole 6 on the inner peripheral surface 7a and in a direction perpendicular to the axial direction of the cylinder hole 6. The hook surface 7b and a taper surface 7c provided at a position facing the hook surface 7b with the inner peripheral surface 7a interposed therebetween.
[0018]
In order to close the opening end of the cylinder hole 6, a metal stopper 8 having an outer diameter approximately the same as the inner diameter of the inner peripheral surface 6a and a resin rod as a closing member are disposed inside the cylinder hole 6. A cap 9 is fitted. The material of the rod cap 9 is not limited to resin, and other materials may be used as long as they are elastically deformable.
[0019]
An elastically deformable claw portion 10 having a locking surface 10a and a tapered surface 10b is provided on the outer peripheral portion of the rod cap 9, and the outer diameter of the claw portion 10 is larger than the inner diameter of the inner peripheral surface 6a. 7 is formed with substantially the same size as the inner peripheral surface 7a. When the rod cap 9 is pushed into the cylinder hole 6, the claw portion 10 is elastically deformed in a direction to reduce its outer diameter by the taper surface 10 b being pushed by the inner peripheral surface 6 a of the cylinder hole 6 and inserted into the cylinder hole 6. Is done. When the claw portion 10 reaches the position of the groove portion 7, the claw portion 10 is elastically deformed so as to return its outer diameter to the original diameter, and engages with the groove portion 7. At this time, since the locking surface 10 a engages with the hooking surface 7 b of the groove portion 7, the rod cap 9 does not come off from the cylinder hole 6. Further, since the stopper 8 has one end surface in contact with the step portion 6c and the other end is in contact with the rod cap 9, the stopper 8 and the rod cap 9 are opposed to the cylinder hole 6 by the hooking surface 7b and the step portion 6c. Will be fixed in the axial direction. Therefore, unlike the conventional pneumatic actuator, the rod cap 9 can be fixed without providing a thread on the inner peripheral surface 6a of the cylinder hole 6 or using a small and thin snap ring. And the assembly time of this fluid pressure actuator can be reduced.
[0020]
The inside of the cylinder hole 6 closed by the stopper 8 and the rod cap 9 is a cylinder chamber 11, in which a piston as an operating member is slidable in the axial direction of the inner peripheral surface 6b. 12 are accommodated. The inside of the cylinder chamber 11 is divided into two pressure chambers 11a and 11b by the piston 12, and the respective pressure chambers 11a and 11b are communicated with a working fluid supply source (not shown) via supply / discharge ports 4 and 5. Yes. By supplying compressed air from the supply / discharge ports 4 and 5 to the pressure chambers 11 a and 11 b, the piston 12 reciprocates linearly in the cylinder chamber 11. A piston rod 2 is fixed to the piston 12, and the piston rod 2 is connected to the outside through through holes 8a and 9a formed in the stopper 8 and the rod cap 9, respectively, and the movement of the piston 12 is externally transmitted. Can be output as work. Reference numeral 12a denotes a piston packing.
[0021]
A rod packing 14 is provided inside a hollow portion 13 defined between the stopper 8 and the rod cap 9. The rod packing 14 is in contact with the outer peripheral surface of the piston rod 2 and the wall surface in the cavity 13 to prevent the compressed air from leaking outside through the through holes 8a and 9a. Further, an O-ring 15 is provided on the outer periphery of the rod cap 9 so as to prevent compressed air from leaking outside between the inner peripheral surface 6a of the cylinder hole 6 and the rod cap 9.
[0022]
By adopting such a structure, it is not necessary to provide a thread on the inner peripheral surface 6a of the cylinder hole 6 or to fix the rod cap 9 using a small thin snap ring as in the conventional pneumatic actuator. Since the groove portion 7 having an inner diameter slightly larger than that of the inner peripheral surface 6a may be formed on the inner peripheral surface 6a, the pneumatic actuator can be reduced in size. Moreover, since the rod cap 9 can be fixed to the cylinder hole 6 only by pushing the rod cap 9 into the cylinder hole 6, the assembling time can be shortened.
[0023]
FIG. 3 is a perspective view showing a modified example of the pneumatic actuator shown in FIG. 1 and showing a pneumatic actuator in which two rod caps are fitted inside a cylinder hole with a rod packing interposed therebetween, and FIG. 4 is shown in FIG. It is sectional drawing which shows the AA cross section of a pneumatic actuator.
[0024]
As shown in FIG. 3, the actuator body 20 is provided with an end face 20a from which the piston rod protrudes, three side faces 20b, 20c, and 20d, and four attachment holes 23 for attaching the pneumatic actuator to a jig or the like (not shown). Mounting surface 20e. The side surfaces 20b, 20c, and 20d are respectively provided with supply / discharge ports 21, 22 so that any one of the supply / discharge ports can be selectively used. In addition, the unused supply / discharge port is blocked by a plug. Also, sensor mounting grooves 20f and 20g are provided between the side surfaces, and the stroke end of the pneumatic actuator can be detected by mounting the sensor in the sensor mounting grooves 20f and 20g. It has become.
[0025]
As shown in FIG. 4, a cylinder hole 24 as a hole with a bottom is formed inside the actuator body 20, and grooves 25 and 26 are formed on the inner peripheral surface 24 a of the cylinder hole 24. These groove portions 25 and 26 are positioned at the inner peripheral surfaces 25a and 26a having inner diameters slightly larger than the inner peripheral surface 24a, and at the end portions of the inner peripheral surfaces 25a and 26a on the opening end side of the cylinder holes 24, respectively. The hooking surfaces 25b and 26b are formed in a direction perpendicular to the axial direction, and the tapered surfaces 25c and 26c are provided at positions facing the hooking surfaces 25b and 26b with the inner peripheral surface 24a interposed therebetween.
[0026]
In order to close the cylinder hole 24, two rod caps 27 and 28 made of resin are fitted in the cylinder hole 24 as a closing member having an outer diameter substantially the same as that of the inner peripheral surface 24a. . The outer periphery of each rod cap 27, 28 is provided with elastically deformable claws 29, 30 having locking surfaces 29a, 30a and tapered surfaces 29b, 30b. The diameter is larger than the inner diameter of the inner peripheral surface 24 and is formed to have substantially the same dimensions as the groove portions 25 and 26. The rod caps 27 and 28 are fixed inside the cylinder hole 24 by engaging the claw portions 29 and 30 with the groove portions 25 and 26, respectively.
[0027]
The inside of the cylinder hole 24 closed by the rod caps 27 and 28 is a cylinder chamber 31, and a piston 32 is provided in the cylinder chamber 31 so as to be slidable in the axial direction of the inner peripheral surface 24a. ing. The inside of the cylinder chamber 31 is divided into two pressure chambers 31a and 31b by the piston 32, and the pressure chambers 31a and 31b are communicated with a working fluid supply source (not shown) via the supply / discharge ports 21 and 22, respectively. ing. By supplying compressed air to the pressure chambers 31 a and 31 b from the supply / discharge ports 21 and 22, 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 the movement of the piston 32 is transmitted to the outside. It can be output as work. Further, a magnet 35 supported by a support 34 is attached to the piston 32, and a sensor attached to the sensor attachment grooves 20f and 20g detects the position of the stroke end in response to the magnetic field of the magnet 35. It has become. 32a is a piston packing.
[0028]
A rod packing 37 as a seal member is provided inside a hollow portion 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 outside.
[0029]
Since the hollow portion 36 provided with the rod packing 37 is formed between two rod caps 27 and 28 fixed independently of each other, a support for receiving the thrust of the piston 32 on the outer periphery of the rod packing 37 is provided. There is no need to provide a member, and therefore the cylinder hole can be made smaller in diameter, so that the pneumatic actuator can be made smaller.
[0030]
FIG. 5 is a modification of the pneumatic actuator shown in FIG. 3, and is a cross-sectional view showing a case where a dust collecting function is added.
[0031]
The basic structure of the pneumatic actuator shown in FIG. 5 is almost the same as that of the pneumatic actuator shown in FIG. 3, but in this modification, a dust collecting function for removing foreign matters generated from the rod packing is added.
[0032]
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, it is necessary to provide a dust collecting function when the pneumatic actuator is used in a clean room.
[0033]
In the cylinder hole 41 formed in the actuator body 40 of this pneumatic actuator, three rod caps 42, 43, 44 have respective claw portions 42 a, 43 a, 44 a provided in the groove portions 41 a, 41 b, 41 c provided in the cylinder hole 41. Are engaged and fixed, and two rod packings 47 and 48 as seal members are provided in hollow portions 45 and 46 provided between the rod caps 42, 43 and 44.
[0034]
The rod packing 47 disposed on the inner side is disposed so as to contact the outer peripheral surface of the piston rod 33 and the inner peripheral surface of the cylinder hole 41 in the same manner as shown in FIG. 3, and the compressed air supplied to the cylinder chamber 31. Is prevented from leaking outside.
[0035]
On the other hand, the rod packing 48 disposed outside collects foreign matter adhering to the piston rod 33. A negative pressure is supplied to the dust collection port 49 which is located between the rod packings 47 and 48 and is opened. Foreign matter collected by the rod packing 48 is collected by this negative pressure. It is sucked in and discharged out of the clean room.
[0036]
It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in this embodiment, the pneumatic actuator is a double-acting single rod cylinder. However, the pneumatic actuator is not limited to this, and a double-acting double rod cylinder or a rack-and-pinion swinging type as disclosed in Japanese Utility Model Publication No. 64-29506. Any pneumatic actuator such as an actuator may be applied.
[0037]
【The invention's effect】
According to the present invention, since the rod cap is fixed by engaging the claw provided in the rod cap with the groove provided in the cylinder hole, the pneumatic actuator can be reduced in size. Further, since the rod cap is fixed by being pushed into the cylinder hole, the assembly time of the pneumatic actuator can be shortened.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a pneumatic actuator according to an embodiment of the present invention.
2 is a cross-sectional view showing an AA cross section of the pneumatic actuator shown in FIG. 1. FIG.
3 is a perspective view showing a modification of the pneumatic actuator shown in FIG. 1 and showing a pneumatic actuator in which two rod caps are fitted inside a cylinder hole with a rod packing interposed therebetween. FIG.
4 is a cross-sectional view showing an AA cross section of the pneumatic actuator shown in FIG. 3;
5 is a cross-sectional view showing a modified example of the pneumatic actuator shown in FIG. 3 and having a dust collecting function added thereto.
[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 / exhaust port 6 Cylinder hole 6a, 6b Inner peripheral surface 6c Step part 7 Groove part 7a Inner peripheral surface 7b Hook surface 7c Tapered surface 8 Stopper 8a, 9a Through hole 9 Rod cap 10 Claw portion 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 surfaces 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 Rod cap 27a, 28a Through hole 9, 30 Claw portion 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 37 Rod packing 40 Actuator body 41 Cylinder hole 41a, 41b, 41c Groove parts 42, 43, 44 Rod caps 42a, 43a, 44a Claw parts 45, 46 Cavity parts 47, 48 Rod packing 49 Dust collection port

Claims (1)

A pneumatic actuator that converts compressed air energy into linear motion of an actuating member and outputs it,
An actuator body having a cylindrical cylinder hole for slidably housing the operating member in the axial direction;
A plurality of grooves each formed in a ring shape on the inner peripheral surface of the cylinder hole;
A plurality of closing members each provided in the cylinder hole and closing the cylinder hole;
A claw portion provided on an outer peripheral portion of each closing member so as to be elastically deformable in a radial direction, and engaging with the groove portion to fix the closing member in the cylinder hole;
And a sealing member disposed between the plurality of closing members.

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