JP3502452B2 - Linear actuator - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear actuator for reciprocating a slide table by introducing pressure fluid from a set of fluid inlet / outlet ports defined in a cylinder tube.

[0002]

2. Description of the Related Art Conventionally, a linear actuator has been used as a means for conveying a work or the like. This linear actuator can convey a work placed on the moving table by linearly reciprocating the moving table along the cylinder tube.

As a linear actuator according to the prior art, for example, there is a technical idea disclosed in Japanese Utility Model Laid-Open No. 5-42716. The fluid pressure cylinder shown in FIG. 6 includes a cylinder main body 1 and a pair of cylinder chambers 2 and 3 horizontally and serially arranged inside the cylinder main body 1.
It is provided between the cylinder chambers 2 and 3, communicates with the cylinder chambers 2 and 3, and opens on the upper surface of the cylinder body 1,
A long hole 4 in which the longitudinal direction of the opening is oriented in the same direction as the direction in which the cylinder chambers 2 and 3 are arranged;
3 and a pair of pressure supply ports (not shown) communicating with each other, and a pair of pistons 5 and 6 that are reciprocally inserted into the cylinder chambers 2 and 3 and move in the same direction at the same time; A rod 7 which is sandwiched by non-adhesive line contact by a line contact, is arranged with the center line vertically, and is arranged above the cylinder body 1 and a rod 7 which moves in the elongated hole 4 according to the pistons 5 and 6; A table 18 connected to the rod, a circulating ball bearing (not shown) incorporated in the table 18, and a raceway groove (not shown) provided in the cylinder body 1 and engaged with the circulating ball bearing. Composed of and. In the figure, reference numerals 8 and 9 denote end covers, and reference numerals 14 and 15 denote pressure chambers.

[0004]

However, in the above fluid pressure cylinder according to the prior art, the cylinder chambers 2 and 3 in which the pistons 5 and 6 reciprocate are formed by the through holes defined in the cylinder body 1. ing. In this case, the cylinder body 1 functions as a guide member for the circulating ball bearing, and the cylinder body 1 needs to be formed of a high hardness material from the viewpoint of wear resistance. Generally, steel is heat-treated to obtain high hardness.
For this purpose, the cylinder chambers 2, 3
After the heat treatment, a grinding process is required to correct the strain. As a result, there is an inconvenience that the manufacturing work becomes complicated and the manufacturing cost rises.

In the fluid pressure cylinder, the reciprocating motion of the pistons 5 and 6 is transmitted to the table 18 via the rod 7 which is sandwiched by the line contact in a non-adhesive state with respect to the pistons 5 and 6. Therefore, for example, when a load is applied to the table 18 due to the weight of the work or the like, the load is transmitted to the connecting portions of the pistons 5 and 6 and the rod 7 which are orthogonal to each other. At that time, the rod 7 is only sandwiched between the pistons 5 and 6 in a non-adhesive state and in line contact, and the pistons 5 and 6 are not supported by long-term use.
There is an inconvenience that the contact surface between the rod 18 and the rod 7 is worn and the movement accuracy of the table 18 is deteriorated.

The present invention has been made in order to overcome the above-mentioned inconvenience, and can be manufactured at a low cost with a simple structure, and at the same time, it is possible to improve the durability without deteriorating the movement accuracy of the table. It is an object of the present invention to provide a linear actuator capable of

[0007]

To SUMMARY OF THE INVENTION To achieve the above object, the present invention, said introduced from a set of fluid and out ports defined in the cylinder tube pressure fluid to the cylinder chamber
By sliding the cylinder chamber of the piston, a linear actuator reciprocates the slide table, and having a through hole penetrating in the axial direction, opening defined by cutting the side surface portion, wherein Aperture
At both ends of the
Formed cylinder tube and the cylinder tube arranged along the axial direction of the cylinder tube, and the bulging portion of the cylinder tube
A rail member disposed between them , a slide table that reciprocates along the axial direction of the rail member, and a pair of pistons and piston rods that are line-symmetrically opposed to each other along the through hole. by defined, a pair of cylinder chambers respectively communicating with the pair of fluid and out ports, it faces in the through hole of the cylinder tube through the opening, of the pair of piston rods which are disposed opposite in surface contact is clamped to the end face, and provided with a joint member integrally displaced with the slide table, the one
The set of fluid inlet / outlet ports is
Formed on the opposite side, the pair of fluid inlet / outlet ports is a cylinder
The cylinder through the orifice provided in the tube
It characterized Rukoto through communication with the chamber.

[0008]

In the above linear actuator according to the present invention, the pressure fluid introduced from one fluid inlet / outlet port is supplied to one side of the cylinder chamber to press the piston. Under the pressing action of the piston, the joint member sandwiched between the pair of piston rods in surface contact is pressed, and the pressing force displaces the joint member. Therefore, the slide table connected to the joint member via the opening is displaced along the axial direction of the rail member.

Further, by introducing the pressure fluid from the other fluid inlet / outlet port and supplying the pressure fluid to the other cylinder chamber, the slide table is displaced in the opposite direction to the above. In this way, the slide table can be reciprocated.

[0010]

Preferred embodiments of the linear actuator according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view of a linear actuator according to an embodiment of the present invention, FIG. 2 is a partial transverse sectional view of FIG. 1, and FIG. 3 is a longitudinal sectional view taken along line III-III of FIG. Figure 4
1 is a front view of FIG. 1, and FIG. 5 is an exploded perspective view of a slide table.

This linear actuator 20 is shown in FIG.
Further, as shown in FIG. 2, basically, the cylinder tube 22 having a long rectangular parallelepiped shape is connected and fixed to the bulging portion 23 (connecting portion) of the cylinder tube 22 with a screw 24, and the cylinder It is composed of a rail member 26 arranged in parallel along the longitudinal direction of the tube 22. The cylinder tube 22 and the rail member 26 are arranged side by side via lateral side portions, respectively, and by integrally connecting them along a substantially horizontal direction, the height direction can be suppressed and the cylinder tube 22 and Slide table
The upper surfaces of the respective balls 28 are formed so as to be substantially flush with each other at the same height (see FIG. 3). The rail member 26 has a plurality of ball bearings (described later) that circulate and roll.
A slide table 28 that reciprocates along the longitudinal direction of the rail member 26 is provided via the. In addition, the slide table 2 is provided on the upper surface of the bulging portion 23, respectively.
An adjusting screw 30 for finely adjusting the amount of displacement of 8 is provided.

On the upper surface of the cylinder tube 22, sensor mounting grooves 32a and 32b for mounting a sensor (not shown) are formed along the longitudinal direction so as to be spaced apart from each other by a predetermined distance and substantially parallel to each other. Further, an opening 36 is formed in the side surface of the cylinder tube 22 facing the slide table 28 so that a joint member 34 described later can be integrally displaced with the slide table 28. Defines a window 40 that allows the protrusion 38 of the joint member 34 to face the inside of the cylinder tube 22 (see FIGS. 2 and 4). A pair of fluid inlet / outlet ports 42a, 42b are defined on the side surface portion on the opposite side where the opening portion 36 is provided, with a predetermined space therebetween.

Further, the cylinder tube 22 is formed with a through hole 44 penetrating along the axial direction of the cylinder tube 22, and a pair of closing members to which seal rings 46 are attached are provided at both ends of the through hole 44. It is closed by 48a and 48b. The protrusion 38 of the joint member 34 having a substantially T-shaped cross section, which is fixed to the side surface of the slide table 28 via a screw 50 (see FIG. 3) in the through hole 44 and is displaced integrally with the slide table 28. Are formed to face. Further, in the through hole 44, a pair of pistons 52a and 52b that are slidably displaced in the X or Y direction along the axial direction of the through hole 34, and a pair of piston rods connected to the pistons 52a and 52b. 54
a and 54b are provided in line symmetry with respect to the protrusion 38 (see FIG. 2). In this case, the closing member 48
a, 48b and pistons 52a, 52b close the through hole 44, thereby forming a pair of cylinder chambers 56a,
56b is defined, and the cylinder chambers 56a, 56b are connected to the fluid inlet / outlet port 42 via orifices 58a, 58b.
a and 42b, respectively. The piston 52a,
A ring-shaped seal member 60 and a magnet 62 for detecting the moving position of the slide table 28 by a sensor (not shown) mounted in the sensor mounting grooves 32a and 32b are fitted on the outer peripheral surface of 52b, respectively. There is. The pair of piston rods 54a and 54b are so formed as to be in surface contact with and sandwich the projection 38 of the joint member 34 in a non-adhesive state.

A plurality of ball bearings 64 for smoothly reciprocating the slide table 28 are provided at a sliding portion between the slide table 28 and the rail member 26. The ball bearings 64 are the rail member 26 and the slide member. While rolling along track grooves 66a and 66b defined so as to face the inner wall surface of the table 28, respectively, it circulates through a circulation hole 68 described later (see FIGS. 3 and 5).

As shown in FIG. 5, the slide table 28 has a table block 70 having a substantially U-shaped cross section, and screw members 72 at both ends in the moving direction of the table block 70. A pair of end covers 74a, 74b and scrapers 76a, 76b to be mounted
Have and. Workpiece mounting holes 78 are defined in the four corners of the upper surface of the table block 70, and screw holes 80 for fixing the joint member 34 are defined in the side surfaces orthogonal to the upper surface. There is. Further, the table block 70 is formed with a pair of circulation holes 68 penetrating along the moving direction, and a plurality of ball bearings 64 roll along the raceway grooves 66a and 66b and circulate through the circulation holes 68. To do. On the end surface of the table block 70, a pair of return guides 80a, 80b are provided which mediate the raceway grooves 66a, 66b and the circulation hole 68 when the ball bearing 64 rolls. A pair of holes 82 is defined in each of the end covers 74a and 74b, and the slide table 28 is formed in the one hole 82.
A damper member 84 that abuts on the adjusting screw 30 at the end position of movement and absorbs an impact generated at the end of movement is inserted.

The linear actuator 20 according to the embodiment of the present invention is basically constructed as described above. Next, its operation and action and effect will be explained.

First, a pressure fluid is introduced into one fluid inlet / outlet port 42a from a fluid pressure supply source (not shown). In this case, the other fluid inlet / outlet port 42b is kept open to the atmosphere under the operation of a switching valve (not shown).

The pressure fluid is supplied to one cylinder chamber 5 through an orifice 58a communicating with the fluid inlet / outlet port 42a.
6a (see FIG. 2). The cylinder chamber 56
The pressure fluid introduced into a presses the piston 52a, and the piston 52a is slidably displaced along the through hole 44 in the axial direction of the cylinder tube 22. As a result, the slide table 28 moves in the direction of the arrow X via the joint member 34 sandwiched between the pair of piston rods 54a and 54b in a surface contact state. In this case, the pressure fluid in the cylinder chamber 56b closed by the other piston 52b and the closing member 48b is led out from the fluid inlet / outlet port 42b in a state of being throttled by the orifice 58b. Therefore, the other piston 52b is slidably displaced in the arrow X direction integrally with the joint member 34. Slide table 28 moving in the direction of the arrow X
The movement end position is regulated by the damper member 84 coming into contact with the end of the adjusting screw 30, while the sensor (not shown) mounted in the sensor mounting groove 32a (32b) detects the magnetic action of the magnet 62. By doing so, the position of the slide table 28 is detected.

When the slide table 28 is moved in the opposite direction (direction of arrow Y), pressure fluid is supplied to the other fluid inlet / outlet port 42b. The supplied pressure fluid is introduced into the cylinder chamber 56b via the orifice 58b and presses the piston 52b in the arrow Y direction. As a result, the slide table 28 is attached to the pair of piston rods 5.
It moves in the arrow Y direction via the joint member 34 which is sandwiched between 4a and 54b in a non-bonded state. Since the other operations are the same as those described above, detailed description thereof will be omitted.

Linear actuator 2 according to the present embodiment
0 means that the cylinder tube 22 and the rail member 26 are arranged side by side integrally in the lateral direction, and the cylinder tube 22 and the slide member 26 are slid together.
Since the upper surfaces of the id tables 28 are formed to be substantially flush with each other, they can be suitably installed when the height direction is limited depending on the usage situation.

A pair of pistons 52a, 52b and a piston rod 54a, which are formed in the same shape as the cylinder tube 22 and the rail member 26, are formed in the through hole 44 defined in the cylinder tube 22. 54
Since it suffices to assemble b so as to be axisymmetric with respect to the joint member 34, and the manufacturing cost can be reduced because the manufacturing can be performed easily.

Further, the joint member 34 is held in contact with the substantially circular smooth end surfaces of the pair of piston rods 54a and 54b without being bonded to the end portions of the piston rods 54a and 54b. Therefore, even when a load is applied to the slide table 28,
Since the contact portion between the slide table 28 and the joint member 34 to which the load is transmitted is firmly coupled and the contact area between the joint member 34 and the piston rods 54a and 54b is large, the joint member 34 and the piston rod 54a, No wear occurs on the contact surface with 54b. As a result, it is possible to improve the durability without deteriorating the movement accuracy of the slide table 28.

[0024]

According to the linear actuator of the present invention, the following effects can be obtained.

That is, the cylinder tube and the rail member are integrally connected, and a pair of pistons to which piston rods are attached are inserted along the through holes defined in the cylinder tube. By assembling the joint members between the piston rods so that they are in surface contact with each other, they can be easily manufactured, and the manufacturing cost can be reduced.

Further, in the linear actuator according to the present invention, the joint member is held in surface contact with the pair of piston rods. Therefore, even when a load is applied to the slide table, the contact portion between the joint member and the piston rod to which the load is transmitted is firmly coupled, and the contact area between the joint member and the piston rod is further increased. Since it is large, wear does not occur on the contact surface between the joint member and the piston rod. As a result, it is possible to improve the durability without deteriorating the movement accuracy of the slide table.

Further, in the linear actuator according to the present invention, the cylinder tube and the rail member are laterally integrally provided side by side, and the cylinder tube and the slide table are integrally arranged.
Since the upper surface of each of the le is formed to be substantially flush,
There is an advantage that it can be suitably installed when the height direction is limited depending on the usage situation.

[Brief description of drawings]

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

2 is a partial cross-sectional view of the linear actuator shown in FIG.

3 is a vertical cross-sectional view taken along the line III-III in FIG.

FIG. 4 is a front view of the linear actuator shown in FIG.

5 is an exploded perspective view of a slide table that constitutes the linear actuator shown in FIG. 1. FIG.

FIG. 6 is a cross-sectional view of a fluid pressure cylinder according to the related art.

[Explanation of symbols]

20 ... Linear actuator 22 ... Cylinder tube 26 ... Rail member 28 ... Slide table 30 ... Adjustment screw 32 ... Sensor mounting groove 34 ... Joint member 36 ... Opening 38 ... Projection 40 ... Window 42a, 42b ... Fluid inlet / outlet port 44 ... Through holes 52a, 52b ... Pistons 54a, 54b
... Piston rods 56a, 56b ... Cylinder chambers 58a, 58b
... Orifice 64 ... Ball bearing 66a, 66b
… Orbit groove

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Kaihei Hei 5-42716 (JP, U) Heikai Hei 4-49204 (JP, U) Hei Kohei 3-29602 (JP, Y2) Hei Kohei 4- 25525 (JP, Y2) (58) Fields investigated (Int.Cl. ⁷ , DB name) F15B 15/00-15/28

Claims (6)

(57) [Claims] Claim: What is claimed is: 1. A pressure fluid is introduced into a cylinder chamber through a set of fluid inlet / outlet ports defined in a cylinder tube,
By sliding the Sunda chamber of the piston, a linear actuator reciprocates the slide table, and having a through hole penetrating in the axial direction, opening defined by cutting the side surface portion, wherein Both ends of the opening
A cylinder tube having a bulged portion extending orthogonally to the side surface portion , and a rail arranged in parallel along the axial direction of the cylinder tube and arranged between the bulged portions of the cylinder tube. A member, a slide table that reciprocates along the axial direction of the rail member, and a pair of pistons and piston rods arranged along the through hole so as to face each other in line symmetry. A pair of cylinder chambers that respectively communicate with the fluid inlet / outlet ports of the pair, and the end faces of the pair of piston rods that face the inside of the through hole of the cylinder tube through the opening and face each other, and sandwich the end faces of the pair of piston rods. And a joint member that is integrally displaced with the slide table , wherein the set of fluid inlet / outlet ports is a cylinder tube.
Of the fluid inlet / outlet port formed on the opposite side of the opening of the
Via the orifice provided in the cylinder tube
Linear actuator according to claim Rukoto through communication with the cylinder chamber Te. 2. The linear actuator according to claim 1, wherein the upper surface of the cylinder tube and the upper surface of the slide table are substantially flush with each other. 3. The linear actuator according to claim 1 or 2 , wherein a long groove for mounting a sensor is defined in the upper surface of the cylinder tube along the longitudinal direction. 4. The linear actuator according to claim 1, wherein the cylinder tube is expanded.
The output unit, for fine-tuning the amount of displacement of the slide table
Linear actuator and providing a displacement adjustment means for. 5. The linear actuator according to claim 4 , wherein the displacement amount adjusting hand is provided on the end surface of the slide table.
A linear actuator, characterized in that each of the linear actuators is provided with a cushioning means which comes into contact with the step and absorbs an impact at a moving end of the slide table . 6. The linear actuator according to claim 1, wherein a magnet for detecting the piston position is mounted on the outer peripheral surface of each of the pair of pistons. .