JP2003222128A - Uniaxial actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a uniaxial actuator with capability to repress generation of noises and vibrations that are ascribable to collisions between spherical rolling bodies and between balls to be able to improve noise-depressing ability and durability. <P>SOLUTION: There are provided resinous separators 25, 28 between the respective spherical rolling bodies 15 and between the respective balls 23 to prevent the mutual collisions between the spherical rolling bodies and between the balls by the separators 25, 28. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a uniaxial actuator used in an XY table device, an industrial robot or the like.

[0002]

2. Description of the Related Art Conventionally, as a uniaxial actuator used in an XY table device, an industrial robot, etc., for example,
The one disclosed in Japanese Patent Application Laid-Open No. 2000-213617 is known, and a uniaxial actuator of this type has a guide rail 11, a slider 12, bearings 17, 1 as shown in FIG.
8, screw shaft 19, nut 21 and motor bracket 2
4 is provided.

The guide rail 11 has a substantially U-shaped cross section along the width direction.
The guide rail 11 is formed in a letter shape, and rolling element rolling grooves 13 are formed on the inner surfaces 11a, 11a of the guide rail 11 which face each other. These rolling element rolling grooves 13 are formed along the longitudinal direction of the guide rail 11 so that the inner surface 1 of the guide rail 11 is
1a, the inner surface 11a of the guide rail 11 is formed.
The rolling element rolling groove 14 is formed on both side surfaces of the slider 12 facing each other.
(See FIG. 8) is formed along the longitudinal direction of the guide rail 11.

The rolling element rolling groove 13 and the rolling element rolling groove 1
4 are opposed to each other, and these rolling element rolling grooves 13,
A large number of spherical rolling elements 15 (see FIG. 5) made of a metal material such as carbon steel are arranged in a line between the rows 14. The slider 12 is a slider body 121 formed in a block shape.
And the end caps 122, 122 attached to the front end surface and the rear end surface of the slider body 121. The rolling element rolling groove 13,
The rolling element return passage 16 (see FIG. 8) for returning the spherical rolling element 15 rolling between 14 to the initial position is the rolling element rolling groove 1
It is formed in parallel with 3, 14. On the other hand, the end cap 122 has a communication passage that connects the rolling element rolling path formed between the rolling element rolling grooves 13 and 14 and the rolling element return passage 16 to form a circulation path for the spherical rolling element 15. Has been formed.

The bearings 17 and 18 are provided at both ends in the longitudinal direction of the guide rail 11, and a ball screw groove 20 is formed on the outer peripheral surface of the screw shaft 19 whose both ends are supported by the bearings 17 and 18. ing. The ball screw groove 20 faces a ball screw groove 22 formed on the inner peripheral surface of the nut 21, and a large number of balls 23 made of a metal material such as carbon steel are provided between the ball screw grooves 20 and 22. Are arranged in a line.

The screw shaft 19 is rotationally driven by a drive motor (not shown). When the rotational torque of the drive motor is transmitted to the screw shaft 19, the ball 23 repeatedly rolls between the ball screw grooves 20 and 22. , Nut 21
Is movable in the axial direction of the screw shaft 19. The nut 21 is integrated with the slider 12, and when the rotational torque of the drive motor is transmitted to the screw shaft 19, the slider 12 moves integrally with the nut 21 in the longitudinal direction of the guide rail 11.

[0007]

In such a uniaxial actuator, since the slider 12 and the nut 21 are integrally structured, the miniaturization can be achieved, but it has the following problems. Was there. That is, in the above-mentioned uniaxial actuator, the spherical rolling element 15 and the ball 23
Since it is made of metal such as carbon steel, there is a problem that noise and vibration occur when rolling elements collide with each other or balls collide with each other during operation.

Therefore, the present invention has been made in view of such problems, and it is an object of the present invention to provide a uniaxial actuator capable of suppressing the generation of noise and vibration due to collision between rolling elements and balls. To aim.

[0009]

In order to achieve the above object, the present invention provides a guide rail, a slider provided on the guide rail so as to be movable relative to each other, and along a longitudinal direction of the guide rail. Rolling element rolling grooves formed so as to face the guide rail and the slider, a plurality of rolling elements arranged in a row between these rolling element rolling grooves, and both longitudinal ends of the guide rail. Bearings provided in the portion, a screw shaft whose both ends are supported by these bearings, a nut having a ball screw groove formed on the outer peripheral surface of the screw shaft and having a ball screw groove facing the inner peripheral surface, A uniaxial actuator comprising the nut and a large number of balls arranged between both ball screw grooves of the screw shaft, the slider and the nut being integrated with each other. Tree between each ball Characterized in that allowed interposing a separator made of.

With such a structure, rolling elements and balls do not collide with each other during operation, so that noise and vibration due to collision of rolling elements and balls can be suppressed, resulting in quietness. The durability and durability can be improved. In this case, as in the invention according to claim 2, the separator is formed in a disk shape, and a concave surface that is in sliding contact with the rolling element and / or the ball is formed on an end surface of the separator, and a radius of curvature of the concave surface is formed. Is set to be larger than the radius of curvature of the rolling element and / or the ball, the contact area between the rolling element and the separator and / or the ball and the separator becomes small. As a result, the sliding resistance of the rolling elements and / or balls becomes relatively small, and a lubricant such as grease easily enters between the rolling elements and / or balls and the concave surface of the separator to drive the screw shaft. The load on the motor can be reduced.

When a lip elastically deformable with respect to the rolling element and / or the ball is provided on the peripheral edge portion of the concave surface, the rolling element and / or the elastic element can be elastically deformed. Alternatively, elastic preload is applied to the balls, and centripetality of the rolling elements and / or balls with respect to the separator is increased when the slider moves straight, so that the zigzag arrangement of the rolling elements and / or balls is suppressed, and
Or the passing movement of the ball is improved.

[0012]

DETAILED DESCRIPTION OF THE INVENTION Referring to FIGS.
An embodiment of the present invention will be described. 1 is a partially cutaway perspective view showing a uniaxial actuator according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the uniaxial actuator according to the embodiment. As shown in FIG. Rail 11, slider 12, bearing 17, 1
8, screw shaft 19, nut 21 and motor bracket 2
4 is provided.

The guide rail 11 has a substantially U-shaped cross section along the width direction.
The guide rail 11 is formed in a letter shape, and rolling element rolling grooves 13 are formed on the inner surfaces 11a, 11a of the guide rail 11 which face each other. These rolling element rolling grooves 13 are formed along the longitudinal direction of the guide rail 11 so that the inner surface 1 of the guide rail 11 is
1a, the inner surface 11a of the guide rail 11 is formed.
The rolling element rolling groove 14 is formed on both side surfaces of the slider 12 facing each other.
(See FIG. 2) is formed along the longitudinal direction of the guide rail 11.

The rolling element rolling groove 13 and the rolling element rolling groove 1
4 are opposed to each other, and these rolling element rolling grooves 13,
A large number of spherical rolling elements 15 (see FIG. 1) made of a metal material such as carbon steel are arranged in a line between the rows 14. The slider 12 is a slider body 121 formed in a block shape.
And the end caps 122, 122 attached to the front end surface and the rear end surface of the slider body 121. The rolling element rolling groove 13,
The rolling element return passage 16 (see FIG. 2) for returning the spherical rolling element 15 rolling between 14 to the initial position is the rolling element rolling groove 1
It is formed in parallel with 3, 14. On the other hand, the end cap 122 connects the rolling element rolling path formed between the rolling element rolling grooves 13 and 14 with the rolling element return passage 16 to form a communication path 122a that forms a circulation path for the spherical rolling element 15. (See FIG. 3) are formed.

The bearings 17 and 18 are provided at both ends in the longitudinal direction of the guide rail 11, and a ball screw groove 20 is formed on the outer peripheral surface of a screw shaft 19 whose both ends are supported by the bearings 17 and 18. ing. The ball screw groove 20 faces a ball screw groove 22 (see FIG. 4) formed on the inner peripheral surface of the nut 21.
In between, a large number of balls 23 made of a metal material such as carbon steel are arranged in a row.

The screw shaft 19 is rotationally driven by a drive motor (not shown). When the rotational torque of the drive motor is transmitted to the screw shaft 19, the ball 23 repeatedly rolls between the ball screw grooves 20 and 22. , Nut 21
Is movable in the axial direction of the screw shaft 19. The nut 21 is integrated with the slider 12 (may be a separate member), so that the rotational torque of the drive motor is controlled by the screw shaft 19
The slider 12 moves integrally with the nut 21 in the longitudinal direction of the guide rail 11 when transmitted to the guide rail 11.

FIG. 3 is a sectional view taken along the line III-III of FIG. 2, and as shown in FIG. 3, the rolling element rolling grooves 13, 1 are formed.
A separator 25 made of synthetic resin is provided between the spherical rolling elements 15 arranged in a line between the four. These separators 25 are formed in a disk shape, and concave spherical surfaces 26 are formed on both end faces of each separator 25, as shown in FIG. The concave spherical surface 26 is in sliding contact with the spherical rolling element 15, and assuming that the radius of curvature of the spherical rolling element 15 is r, the radius of curvature R of the concave spherical surface 26 is set to R> r. Further, the separator 25 has a plurality of lips 27 (see FIG. 6) on the peripheral edge of the concave spherical surface 26, and these lips 27 are elastically deformable with respect to the spherical rolling element 15.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 2, and as shown in the figure, the ball screw grooves 20, 22 are shown.
A separator 28 made of synthetic resin is provided between the balls 23 arranged in a line. These separators 28 are formed in a disk shape, and each separator 2
As shown in FIG. 5, concave spherical surfaces 26 are respectively formed on both end surfaces of 8. This concave spherical surface 26 is a ball 23
And the radius of curvature of the ball 23 is r,
The radius of curvature R of the concave spherical surface 26 is set to R> r. Further, the separator 28 has a plurality of lips 27 (see FIG. 6) on the peripheral edge of the concave spherical surface 26.
Is elastically deformable with respect to the ball 23.

In the uniaxial actuator 10 constructed as described above, since the resin separators 25 and 28 are provided between the spherical rolling elements 15 and between the balls 23, as described above, the spherical rolling elements are in contact with each other during operation. And balls do not collide with each other. Therefore, it is possible to suppress the generation of noise and vibration due to the collision between the spherical rolling elements or the balls, and it is possible to improve the quietness and the durability.

Further, since the radius of curvature R of the concave spherical surface 26 formed on both end faces of the separators 25 and 28 is set larger than the radius of curvature r of the spherical rolling element 15 and the ball 23, the rolling element 15 and the separator 25. Also, the contact area between the ball 23 and the separator 28 is reduced. As a result, the sliding resistance of the rolling elements 15 and the balls 23 becomes relatively small, and the rolling elements 15 and the balls 23 and the separators 25, 2
Since a lubricant such as grease easily enters between the concave spherical surface 26 of FIG. 8 and the concave spherical surface 26, the load on the motor that drives the screw shaft 19 can be reduced.

Further, when the rolling elements 15 and the balls 23 press the separators 25, 28, the separators 25, 28
The lip 27 is elastically deformed. As a result, the rolling element 15
Since elastic preload is applied to the balls 23 and the balls 23, the centripetality of the rolling elements 15 and the balls 23 with respect to the separators 25 and 28 at the time of the straight movement of the slider 12 is enhanced.
The staggered arrangement of the balls 5 and the balls 23 is suppressed, and the passing motion of the rolling elements 15 and the balls 23 is improved.

The present invention is not limited to the above embodiment. For example, although the separators 25 and 28 are formed in a disk shape in the above-described embodiment, the separators 25 and 28 do not necessarily have to be formed in a disk shape. Further, in the above-described embodiment, the separators 25 and 28 are made of synthetic resin, but the separators 25 and 28 may be made of, for example, a resin having a lubricant impregnating property. further,
Although the example in which the separators 25 and 28 have the plurality of lips 27 on the peripheral edge portion of the concave spherical surface 26 is shown, the lips 27 are not necessarily required. Furthermore, the rolling element rolling grooves 13, 1
Although the example in which the spherical rolling element 15 is arranged between the four rolling elements is shown, a roller-shaped rolling element may be used instead of the spherical rolling element. In this case, the shapes of the rolling element rolling groove and the concave surface of the separator 25 are
Naturally, the shape should match the shape of the roller.

[0023]

As described above, according to the uniaxial actuator of the first aspect of the present invention, the rolling elements and the balls do not collide with each other during operation, so that the rolling elements and the balls collide with each other. Generation of noise and vibration can be suppressed, and quietness and durability can be improved.

According to the uniaxial actuator of the second aspect of the present invention, in addition to the above-mentioned effects, the sliding resistance of the spherical rolling element and the ball becomes relatively small, and the concave spherical surface and the rolling element, and the concave spherical surface and the ball Lubricant such as grease easily enters between them, and the load on the motor that drives the screw shaft can be reduced. According to the uniaxial actuator of the third aspect of the invention, in addition to the effects described above, the zigzag arrangement of the rolling elements and the balls is suppressed, and the passing motion of the rolling elements and the balls is improved.

[Brief description of drawings]

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

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

3 is a sectional view taken along the line III-III of FIG.

4 is a cross-sectional view taken along the line IV-IV in FIG.

5 is a cross-sectional view of the separator shown in FIGS. 3 and 4. FIG.

6 is a perspective view of the separator shown in FIGS. 3 and 4. FIG.

FIG. 7 is a partially cutaway perspective view showing a conventional uniaxial actuator.

8 is a sectional view of the uniaxial actuator shown in FIG.

[Explanation of symbols]

11 Guide rail 12 sliders 13 Rolling element rolling groove 14 Rolling element rolling groove 15 Spherical rolling element 16 Rolling element return passage 17 Bearing 18 bearings 19 screw shaft 20 ball screw groove 21 nuts 22 Ball screw groove 23 balls 24 motor bracket 25 separator 28 Separator 26 concave spherical surface 27 lips

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3J062 AA21 AA38 AB22 AC07 BA16                       BA26 CD08 CD22 CD54 CD63                 3J101 AA02 AA42 AA52 AA81 AA85                       BA13 BA14 BA20 EA02 EA31                       FA01 FA31 GA60                 3J104 AA03 AA23 AA33 AA34 BA33                       BA61 CA13 DA02 DA06 EA06                       EA07

Claims (3)

[Claims] 1. A guide rail, a slider provided on the guide rail so as to be movable relative to each other, and a rolling element rolling member formed to face the guide rail and the slider along a longitudinal direction of the guide rail. A moving groove, a large number of rolling elements arranged in a line between these rolling elements, a bearing provided at both ends in the longitudinal direction of the guide rail, and both ends supported by these bearings. A screw shaft, a nut having a ball screw groove formed on the outer peripheral surface of the screw shaft and having a ball screw groove facing the ball screw groove on the inner peripheral surface, and arranged between the nut and the ball screw groove of the screw shaft. In a uniaxial actuator including a large number of balls and configured by integrating the slider and the nut, a separator made of resin is interposed between the rolling elements and / or the balls. Axis Actuator. 2. The separator is formed in a disc shape, and a concave surface that slides in contact with the rolling element and / or the ball is formed on an end surface of the separator, and a radius of curvature of the concave surface is the rolling element and / or the rolling element. The uniaxial actuator according to claim 1, wherein the radius of curvature of the ball is set larger than that of the ball. 3. The uniaxial actuator according to claim 2, wherein a lip that is elastically deformable with respect to the rolling element and / or the ball is provided on a peripheral portion of the concave surface.