JP2541630Y2 - Actuator - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an actuator, in particular, a rod supported by a linear bearing.
The present invention relates to an improvement of a pneumatic actuator for sealing the outer periphery of the rod with a spline seal.

[0002]

2. Description of the Related Art Conventionally, as this type of actuator, as shown in Japanese Utility Model Application Laid-Open No. 62-202504, a rod is supported by a linear bearing, and the outer periphery of the rod is sealed by a seal portion. ing. As shown in FIG. 8, a spline groove 53 is formed on the peripheral surface 52 of the rod 51 so as to rollably engage a row of linear bearings (not shown). A spline seal (not shown) made of a rubber-like elastic material is separately developed as a seal portion. The spline seal is formed on an inner peripheral edge of the spline groove so that air pressure does not leak along the spline groove 53. A projection slidably engaging with 53 is formed.

[0003]

The above prior art has the following problems. a. When manufacturing the rod 51, the peripheral surface 52 of the rod 51 is used.
And the wall surface of the spline groove 53 are polished by a grindstone, thereby forming a sharp corner 54 on the side edge of the spline groove 53 as shown in FIG. Therefore, the spline seal may be damaged in a short period of time because the spline seal comes into contact with the sharp corner 54 and slides. b. The spline seal is formed by a mold. In this molding by the mold, a concave radius is always formed on the side edge of the projection. Since a gap is formed between the concave radius and the sharp corner 54, air pressure may leak from the gap.

[0004]

SUMMARY OF THE INVENTION In view of the above, the present invention has been devised in order to solve the above-mentioned problems in the prior art. In an actuator in which a spline groove for rotatably engaging a bearing row of a linear bearing is formed and a projection formed on an inner peripheral edge of a spline seal is slidably engaged with the spline groove, plating is performed on a peripheral surface of the rod. An actuator is provided, wherein a layer is provided, and a radius is provided on a surface of a portion of the plating layer that covers a side edge of the spline groove (claim 1). The spline seal is preferably formed of a soft urethane wear-resistant elastic material (claim 2). The present invention is applied not only to an actuator for linearly moving a rod but also to an actuator for linearly moving a rod and rotating or swinging the rod (claim 3).

[0005]

A plating layer is provided on the peripheral surface of the rod, and a radius is provided on the surface of the plating layer which covers the side edge of the spline groove, and a spline seal is brought into contact with the radius.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

As shown in FIG. 1, a cylinder chamber 2 is formed inside a body 1, a piston 3 is inserted in the cylinder chamber 2 so as to be able to move directly, and a rod 4 is connected to the piston 3. A piston seal 5 and a permanent magnet 6 for position detection are attached to the outer peripheral surface of the piston 3, a stopper 7 made of rubber-like elastic material for cushioning is attached to an end surface of the piston 3, and a shaft 8 is attached to a peripheral surface 8 of the rod 4. A required number (three in the figure) of spline grooves 9 are formed parallel to each other along the direction. The rod 4 protrudes outside the body 1 at one end (the left end in the figure), and the one end is used as the working end. A linear ball bearing 10 is fixed inside the body 1, and the linear ball bearing 10 includes a bearing row 11 composed of a large number of balls that rollably engage with the spline grooves 9. A rod seal holder 12 is fixed inside the body 1 along with the linear ball bearing 10, and a spline seal 13 made of a rubber-like elastic material is supported by the rod seal holder 12. As shown in FIGS. 2 to 4, the spline seal 13 has the same number of protrusions 14 as the spline grooves 9 on the inner peripheral edge of the V-shaped annular body.

As shown in FIG. 5, the spline groove 9 has an arc-shaped cross section, and the rod 4 on which the spline groove 9 is formed is formed.
During manufacturing, the peripheral surface 8 and the wall surfaces of the spline grooves 9 are polished with a grindstone in order to keep the dimensional accuracy at a high level, whereby the side edges of the spline grooves 9 are sharpened as shown in FIG. A corner 15 is formed. And this sharp corner 1
If the spline seals 5 are left as they are, the spline seals 13 come into contact with the sharp corners 54 and slide, so that the spline seals 13 may be damaged in a short time. In order to prevent this, after polishing, the actuator is provided with a plating layer 16 on the peripheral surface 8 of the rod 4 as shown in FIGS. 5 and 6, and covers the side edge of the spline groove 9 of the plating layer 16. The radius 17 is provided on the surface of the portion to be formed.
The plating layer 16 is hard chrome plating, and the plating layer 1
6 is 5 to 10 μm in actual size, and the size of the radius 17 is also formed to 5 to 10 μm. If the thickness of the plating layer 16 exceeds 10 μm, it affects the dimensions of the spline grooves 9 and adversely affects the accuracy of supporting the linear ball bearing 10. If the thickness of the plating layer 16 is less than 5 μm, the thickness of the plating layer 16 decreases. 16 becomes insufficient. As shown in FIG. 2, the projection 14 of the spline seal 13 is formed in an arc shape in accordance with the shape of the spline groove 9 when viewed from the axial direction. The spline seal 13 is formed by a mold, and a concave radius (not shown) is formed on a side edge of the projection 14 in accordance with the molding. The concave radius and the convex radius of the plating layer 16 are formed. There is no gap due to the match with the radius 17.

The actuator having the above structure is connected to a piston 3 of the cylinder chamber 2 through a fluid pressure supply port (not shown).
The air pressure is alternately supplied to the spaces on both sides of the piston 3 to linearly move the piston 3 and the rod 4 connected to the piston 3 in the axial direction.

The actuator having the above configuration has the following effects. a. A plating layer 16 is provided on the peripheral surface 8 of the rod 4, and a radius 17 is provided on a surface of a portion of the plating layer 16 which covers a side edge of the spline groove 9, and the spline seal 13 is brought into contact with the radius 17 to slide. To move it,
The spline seal 13 has a sharp corner 15 as in the prior art.
To prevent damage in a short period of time. b. A plating layer 16 is provided on the peripheral surface 8 of the rod 4, and a radius 17 is provided on a surface of a portion of the plating layer 16 which covers the side edge of the spline groove 9. Since it is made to match with the concave R of the side edge of 14, it is possible to prevent the air pressure from leaking due to a gap as in the prior art. c. When the rod 4 is easily rusted, for example, made of steel, the plating layer 16 is provided on the peripheral surface 8 of the rod 4 to provide a rust prevention effect, and the spline seal 13 is provided by rust.
Can be prevented and the linear ball bearing 10 can be prevented from being damaged.

Although the spline seal 13 can be formed of various rubber-like elastic materials, a sufficient effect on wear resistance can be obtained by forming the spline seal 13 from a soft urethane-based wear-resistant elastic material. Also, by molding with soft rubber, it receives air pressure and is strongly pressed against the rod 4, so that a sufficient effect on the sealing performance can be obtained.

The number of the spline grooves 9 is three as an example, but may be two or less or four or more. Although the linear bearing is an example of a ball bearing, a roller bearing may be used. Although one linear bearing is provided for one actuator as an example, two or more linear bearings may be provided. The plating layer 16 is exemplified by hard chrome plating, but any other plating may be used as long as it can form a uniform layer and maintain the surface roughness.

The present invention is applied not only to an actuator for linearly moving the rod 4 but also to an actuator for linearly moving the rod 4 and rotating or swinging the rod 4 as shown in FIG. The actuator of FIG.
The linear ball bearing 10 is supported by a rotor 18, the rotor 18 is rotatably supported by an angular ball bearing 19, and the rotor 18 is
The piston 4 is connected via a rack and pinion 22 so that the rod 4 is swung by the supply of air pressure.

[0014]

[Effects of the Invention] The present invention has the following effects. a. A plating layer is provided on the peripheral surface of the rod.
Since a radius is provided on the surface of the portion covering the side edge of the spline groove, and the spline seal is brought into contact with the radius and slid, the spline seal rubs at a sharp corner as in the prior art, and is short-lived. It can be prevented from being damaged during the operation. b. A plating layer is provided on the peripheral surface of the rod.
A radius is provided on the surface of the portion covering the side edge of the spline groove, and the convex radius is matched with the concave radius of the side edge of the projection of the spline seal. This can prevent the air pressure from leaking. c. If the rod is easily rusted, a plating layer is provided around the rod to provide a rust-preventing effect, which prevents the spline seal from being worn due to rust and the linear ball bearing from being damaged. it can. d. The spline seal can be formed of various rubber-like elastic materials, but a sufficient effect on wear resistance can be obtained by forming the spline seal with a soft urethane-based wear-resistant elastic material. e. The present invention is applicable not only to an actuator for linearly moving a rod, but also to an actuator for linearly moving a rod and rotating or swinging a rod,
The above effects a to d can also be obtained with this type of actuator.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an actuator according to a first embodiment of the present invention.

FIG. 2 is a front view of a spline seal.

FIG. 3 is a sectional view of a spline seal.

FIG. 4 is a perspective view of a spline seal.

FIG. 5 is a sectional view of a rod.

FIG. 6 is an enlarged view of a portion A in FIG.

FIG. 7 is a sectional view of an actuator according to a second embodiment of the present invention;

FIG. 8 is a cross-sectional view of a rod according to a conventional example.

9 is an enlarged view of a portion B in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 2 Cylinder chamber 3, 21 Piston 4 Rod 5 Piston seal 6 Permanent magnet 7 Stopper 8 Peripheral surface 9 Spline groove 10 Linear ball bearing 11 Bearing row 12 Rod seal holder 13 Spline seal 14 Projection 15 Square 16 Plating layer 17 R 18 Rotor 19 angular contact ball bearing 20 rotary actuator 22 rack and pinion

Claims (3)

(57) [Scope of request for utility model registration] A linear bearing (1) is provided on a peripheral surface (8) of a rod (4).
The spline groove 9 for rotatably engaging the bearing row 11 is formed, and the projection 14 formed on the inner peripheral edge of the spline seal 13 is slidably engaged with the spline groove 9. An actuator characterized in that a plating layer 16 is provided on the peripheral surface 8 of the substrate, and a radius 17 is provided on the surface of the plating layer 16 covering the side edge of the spline groove 9. 2. The actuator according to claim 1, wherein said spline seal is formed of a soft urethane-based wear-resistant elastic material. 3. The actuator according to claim 1, wherein the actuator moves the rod 4 directly and rotates or swings the rod 4.