JP2003230251A - Uniaxial actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a uniaxial actuator which is compact and is small in number of parts, in a uniaxial actuator where the slider of a direct-acting guide bearing and the nut of a ball screw are united together. <P>SOLUTION: The screw shaft 15 of the ball screw and the motor shaft 171 of a drive motor 17 for driving the same shaft 15 are made integrally, which obviates the necessity of a coupling for coupling the screw shaft 15 with the motor shaft 171. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-axis actuator used in an XY table device, an industrial robot, and the like, and more particularly, to a single-axis actuator integrated with a motor. 2. Description of the Related Art Conventionally, as a uniaxial actuator used in an XY table device, an industrial robot, or the like, for example,
One disclosed in Japanese Patent Application Laid-Open No. 2000-213617 is known. As shown in FIG. 4, the uniaxial actuator includes a guide rail 11, a slider 12 provided on the guide rail 11, and a plurality of rolling elements for relatively moving the slider 12 in the longitudinal direction of the guide rail 11. (Not shown), and bearing units 13 and 14 are provided at both ends in the longitudinal direction of the guide rail 11 so as to face each other. In addition, this type of uniaxial actuator includes a screw shaft 15 having both ends supported by bearing units 13 and 14, and a ball screw groove formed on an outer peripheral surface of the screw shaft 15 and facing a ball screw groove on an inner peripheral surface. A nut (not shown) having
The slider 12 includes a nut and a number of balls disposed between the two ball screw grooves of the screw shaft 15, and the slider 12 and the nut are integrated. [0003] The screw shaft 1 of such a single-axis actuator.
5 is connected to a motor shaft 171 of a drive motor 17 via a coupling 18. When the rotation torque of the drive motor 17 is transmitted to the screw shaft 15, the slider 12 integrated with the nut moves in the longitudinal direction of the guide rail 11. It reciprocates. However, in the above-described single-axis actuator, since the screw shaft 15 and the motor shaft 171 are connected by the coupling 18, the overall length of the device is reduced by the amount of the coupling. This has been a factor that hinders downsizing of the device. Also, in order to facilitate the mounting of the motor 17, the coupling 18
In the case where is a coupling having a centering function, there is a problem that the length and diameter of the coupling itself are increased, and accordingly, the size of the uniaxial actuator is increased. The present invention has been made in view of such a problem, and has as its object to provide a compact single-axis actuator having a small number of parts. In order to achieve the above object, the present invention provides a slider provided on a guide rail and a slider for relatively moving the slider in the longitudinal direction of the guide rail. A large number of rolling elements, bearing units provided opposite to both ends in the longitudinal direction of the guide rail, a screw shaft having both ends supported by these bearing units, and formed on the outer peripheral surface of the screw shaft. Having a ball screw groove on its inner peripheral surface facing the ball screw groove, a number of balls disposed between the nut and the ball screw grooves of the screw shaft, and a drive motor for rotating the screw shaft With
In a single-axis actuator obtained by integrating the slider and the nut, the screw shaft and the motor shaft of the drive motor are integrally formed. In the present invention, since the screw shaft and the motor shaft of the drive motor are integrally formed, a coupling for connecting the screw shaft and the motor shaft of the drive motor becomes unnecessary, and the length of the single shaft actuator is reduced. Since the length is shortened by the coupling, the size of the uniaxial actuator can be reduced, and the number of parts of the uniaxial actuator can be reduced. In addition, since the centering of the screw shaft and the motor shaft is not required, the assembling work of the single-axis actuator can be easily performed in a short time. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 to 3,
An embodiment of the present invention will be described. 1 to 3 show one embodiment of the present invention (hereinafter abbreviated as the present embodiment). FIG. 1 is a plan view of a uniaxial actuator according to the present embodiment, FIG. 2 is a perspective view of the actuator, FIG. 3 is a perspective view showing the actuator with a part cut away. As shown in FIGS. 1 and 2, a single-axis actuator 10 according to this embodiment includes a guide rail 11, a slider 12, a screw shaft 15, a nut 16, and a drive motor 1.
7 is provided. The guide rail 11 has a recess 111 extending in the longitudinal direction at the center of the upper surface, and rolling element rolling grooves 19 are formed on opposing side walls of the recess 111 as shown in FIGS. 2 and 3. Is formed.
These rolling element rolling grooves 19 are formed on the side wall surface of the concave portion 111 along the longitudinal direction of the guide rail 11, and the concave portion 1
Roller rolling grooves 20 are formed on both side surfaces of the slider 12 facing the side wall surface of the slider 11, respectively. The rolling element rolling groove 20 is provided with a rolling element rolling groove 19.
A large number of spherical rolling elements 21 (see FIG. 3) for relatively moving the slider 12 in the longitudinal direction of the guide rail 11 are rotatable between the two rolling element rolling grooves 19 and 20. It is arranged in. As shown in FIG. 3, the slider 12 includes a slider block 121 provided on the guide rail 11, and an end cap 122 attached to the front end face and the rear end face of the slider block 121. A rolling element return path 22 for returning the rolling element 21 that has rolled between the rolling element rolling grooves 19 and 20 to the initial position is formed in the 121 corresponding to the rolling element rolling grooves 19 and 20. . The rolling element return path 22 is connected to the slider block 12
1 are open at the front end face and the rear end face, and the rolling element rolling grooves 1
An end cap 122 that closes the open end of the rolling element rolling path formed between 9 and 20 connects the rolling element rolling path and the rolling element return path 22 to form a circulation path for the rolling element 21. A U-shaped direction changing groove 23 (see FIG. 3) is formed. The screw shaft 15 is supported at both ends by bearing units 13 and 14 provided at both ends in the longitudinal direction of the guide rail 11. The screw shaft 15 is provided in the concave portion 111 of the guide rail 11, and a ball screw groove 24 (see FIGS. 2 and 3) is formed on the outer peripheral surface of the screw shaft 15. The nut 16 is integrated with the slider 12, and a ball screw groove 25 (see FIG. 3) is formed on the inner peripheral surface of the nut 16. The ball screw groove 25 is opposed to the ball screw groove 24 of the screw shaft 15, and a large number of balls 26 (see FIG.
) Is arranged to be able to roll freely. The nut 16
Is provided with a ball circulation tube 27 for circulating the ball 26. The drive motor 17 has a motor shaft 171 (see FIG. 1). The motor shaft 171 is formed integrally with the screw shaft 15. The drive motor 17 has a motor housing 172, and a motor stator is mounted on an inner surface of the motor housing 172 so as to face a motor rotor provided on a motor shaft 171. In the single-axis actuator 10 configured as described above, as described above, the screw shaft 15 and the drive motor 1
Since the motor shaft 171 is integrally formed, the coupling for connecting the screw shaft 15 and the motor shaft 171 becomes unnecessary. Thus, the length of the single-axis actuator is shortened by the amount of the coupling, so that the size of the single-axis actuator can be reduced. Also, screw shaft 1
Since the coupling for connecting the motor shaft 171 to the motor shaft 171 is not required, the number of parts can be reduced, and the labor for selecting the coupling can be saved. In addition, since the centering of the screw shaft 15 and the motor shaft 171 is not required, the work of assembling the uniaxial actuator can be easily performed in a short time. Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. As described above, according to the present invention,
The coupling for connecting the screw shaft and the motor shaft is not required, and the length of the single-axis actuator is shortened by the amount of the coupling, so that the single-axis actuator can be made compact and the number of parts can be reduced. .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a uniaxial actuator according to an embodiment of the present invention. FIG. 2 is a perspective view of the uniaxial actuator shown in FIG. FIG. 3 is a perspective view of the uniaxial actuator shown in FIG. FIG. 4 is a plan view of a conventional uniaxial actuator. DESCRIPTION OF SYMBOLS 11 Guide rail 12 Slider 13 Bearing unit 14 Bearing unit 15 Screw shaft 16 Nut 17 Drive motor 19 Rolling element rolling groove 20 Rolling element rolling groove 21 Rolling element 22 Rolling element return path 23 Direction changing groove 24 Ball Screw groove 25 Ball screw groove 26 Ball 27 Ball circulation tube 121 Slider block 122 End cap 171 Motor shaft

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Claims (1)

Claims: 1. A slider provided on a guide rail,
Numerous rolling elements for relatively moving the slider in the longitudinal direction of the guide rail, bearing units provided opposite to both longitudinal ends of the guide rail, and both ends supported by these bearing units A screw shaft, a nut having an inner peripheral surface with a ball screw groove facing a ball screw groove formed on the outer peripheral surface of the screw shaft, and a nut disposed between the ball screw groove of the nut and the screw shaft. A plurality of balls, and a drive motor for driving the screw shaft to rotate, wherein the slider and the nut are integrated, and the screw shaft and the motor shaft of the drive motor are integrally formed. A uniaxial actuator characterized by the above-mentioned.