JP3626375B2 - Driving mechanism for moving body and parallel mechanism machine using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a parallel mechanism in which a plurality of link mechanisms are provided on a moving body so that the position and posture of the moving body can be changed.
[0002]
[Prior art]
A ball screw telescopic parallel mechanism machine is shown in FIG. As shown in the figure, a ball screw 8 with a plurality of splines penetrates through a fixed base 1 (base) through an upper rotary joint 21 and is attached to be movable in the axial direction to form a link mechanism. doing. The tip of the ball screw 8 is connected to the corner of the moving body 20 via the lower rotary joint 19. Each upper rotary joint 21 is continuously provided with a servo motor 22, and the position and posture of the moving body 20 can be changed by moving the ball screw 8 as a link in the axial direction.
[0003]
In order to make the position and posture of the moving body 20 variable by a plurality of links, a rotary joint for tilting the ball screw in an arbitrary direction is required together with a driving device that moves the ball screw 8 in the axial direction. However, in the case of FIG. 8, as a ball screw driving device in which these two devices are combined into one, an upper rotary joint is formed by a servo motor 22 having a spherical outer bearing, and the ball screw nut 6 (see FIG. 9). A nut rotation type driving device that directly drives (shown) has been used in the past.
The feature of this drive device was that it was possible to make the shape very compact compared to the belt drive by arranging a servo motor on a spherical sliding bearing and directly driving the nut. However, it has been difficult to pursue the processing accuracy of spherical sliding bearings, to manage bearing intervals, to improve bearing rigidity, to maintain servo motors, and to increase torque.
[0004]
Therefore, as a means for solving these problems, a rotary joint-integrated ball screw driving device has been proposed. 9 to 11 show specific examples thereof, FIG. 9 is a longitudinal sectional view of the driving device, FIG. 10 is a longitudinal sectional view of a plane orthogonal to the section of FIG. 9, and FIG. 11 is a plan view. In the figure, 2 is an outer ring, 3 is an intermediate ring, and 4 is an inner ring. As shown in FIG. 11, two jigs 5a provided at opposite positions of the outer ring 2 are orthogonal to the jig 5a. A gimbal structure is formed by two jigs 5b provided at opposite positions of the intermediate ring 3 so as to support the ball screw 8. The servo motor 22 is formed continuously with the inner ring 4.
In this way, by configuring the gimbal structure with a pre-loaded rolling bearing, a highly rigid rotary joint with no gap is realized, and by separating the servo motor and rotary joint, only the servo motor can be attached and detached. The servo motor maintenance and torque increase are made easy.
[0005]
[Problems to be solved by the invention]
However, in this way as a ball screw drive device integrated with a rotary joint,
When more rigidity is required, a complicated gimbal structure is an obstacle, and satisfactory rigidity cannot be obtained.
[0006]
Therefore, the object of the present invention is to provide two degrees of freedom in the direction in which the ball screw falls, which the rotation joint-integrated ball screw driving device has, one degree of freedom in rotation in the direction in which the ball screw falls, and rotation on the base plane. As a simple structure by changing to one degree of freedom, a rotary joint integrated ball screw drive device that eliminates one trunnion structure connected in series and a high-rigidity moving body drive mechanism and the same are used. To provide a parallel mechanism machine.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problem, a driving mechanism for a moving body according to the invention of claim 1 includes a base, a moving body, a plurality of first universal joints provided on an outer edge of the moving body, and the base. A plurality of second universal joints provided on an outer edge of the first universal joint, and one end connected to the first universal joint and the other end attached to the second universal joint so as to be axially movable. links and, in the driving mechanism of a moving body and means for axially moving each said link relative to said second universal joint, said second universal joint, before rotatably in Kimotodai plane and while the ring in that will be installed, together with the link is connected in a state of penetrating, rotatably supported in a direction in which the said link to the intermediate ring from falling down by two opposing axis fixed to the position of the intermediate ring formed by the inner ring to be, before A second universal joint, characterized in that with two rotational degrees of freedom consisting of one rotation degree of freedom on one rotation degree of freedom and the base plane in the direction of the link from falling down.
[0008]
The invention according to claim 2 is characterized in that the parallel mechanism machine is provided with the drive mechanism for the moving body according to claim 1.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an example of a driving mechanism for a moving body according to the present invention, which is a longitudinal sectional view of a rotary joint integrated ball screw driving device, and FIG. 2 is a plan view thereof. As shown in the figure, a splined ball screw 8 constituting a link is supported by a ball screw nut 6 and a spline nut 7, and is attached to the base 1 through the base 1.
[0010]
The spline nut 7 is supported by the inner ring 4, the inner ring 4 is rotatably supported by two jigs 5 fixed at opposite positions of the intermediate ring 3, and the intermediate ring 3 is a cross roller bearing provided with a preload. It is attached to the base 1 through 23. The inner ring 4 is connected to a servo motor 22 that moves the ball screw 8 in the axial direction.
[0011]
As shown in FIG. 3 which is an enlarged view of part A of FIG. It is supported by a tapered roller bearing 15 which is provided and attached. Reference numeral 17 denotes a collar for fixing the tapered roller bearing 15, and 18 denotes a nut.
The servo motor 22 includes the rotor 9, the stator 10, the angular bearing 11, the deep groove ball bearing 12, the brake 13, the rotary encoder 14, and the like, and the ball screw nut 6 is connected to the tip of the rotor 9. The ball screw 8 can be moved in the axial direction by rotation.
[0012]
Thus, by changing the conventional two degrees of freedom of rotation to one degree of freedom of rotation in the direction in which the ball screw is tilted and one degree of freedom of rotation on the base plane, the rotation without one trunnion structure connected in series is eliminated. A joint-integrated ball screw drive device can be realized, and a highly rigid rotary joint can be realized.
[0013]
4 to 6 show other forms of cross roller bearings. FIG. 4 shows a case where a three-row cylindrical roller bearing is used, FIG. 5 shows an angular bearing, and FIG. An arc-shaped ball guide is used. In any case, a high-rigidity rotary joint can be formed by applying a high preload to the bearing portion.
FIG. 7 shows still another embodiment, in which a hydrostatic bearing 28 is used instead of the cross roller bearing. With this configuration, high vibration damping performance can be obtained with high rigidity.
The rotary joint portion as described above is applied to the drive mechanism of the moving body of the parallel mechanism machine shown in FIG. 8, that is, the lower rotary joint that is the first universal joint and the upper rotary joint that is the second universal joint. Thus, a highly rigid parallel mechanism machine can be obtained.
[0014]
【The invention's effect】
As described in detail above, according to the first aspect of the invention, the two degrees of freedom of rotation in the direction in which the ball screw is tilted, which the conventional rotary joint-integrated ball screw driving device has, is in the direction in which the ball screw is tilted. By changing to one rotation degree of freedom and one degree of freedom rotation on the base plane, one trunnion structure connected in series is eliminated, and a more rigid moving body drive device can be realized.
According to the invention of claim 2, a highly rigid and highly accurate parallel mechanism machine can be realized.
[Brief description of the drawings]
FIG. 1 is an explanatory view of a longitudinal section of a moving body drive mechanism showing an example of an embodiment of the present invention.
2 is a plan view of FIG. 1. FIG.
FIG. 3 is an enlarged view of a portion shown in FIG. 1A.
FIG. 4 is a cross-sectional view of a main part showing another embodiment of the present invention.
FIG. 5 is a cross-sectional view of a main part showing another embodiment of the present invention.
FIG. 6 is a cross-sectional view of a main part showing another embodiment of the present invention.
FIG. 7 is a cross-sectional view of a main part showing another embodiment of the present invention.
FIG. 8 is a perspective view of a parallel mechanism machine.
FIG. 9 is a longitudinal sectional view illustrating an example of a conventional moving body drive mechanism.
10 is an explanatory view of a vertical cross section orthogonal to the cross section of FIG. 8. FIG.
11 is a plan view of FIG. 8. FIG.
[Explanation of symbols]
1 ・ ・ Base (base) 3 ・ ・ Intermediate ring 4 ・ ・ Inner ring 5 ・ ・ Screw 6 ・ ・ Ball screw nut 7 ・ ・ Spline nut 8 ・ ・ Ball screw with spline 19 ・ ・Lower rotary joint (first universal joint), 20 ... moving body, 21 ... upper rotary joint (second universal joint), 22 .... servo motor, 23 ... cross roller bearing, 24 ... 3 rows Cylindrical roller bearing, 25 ... Angular contact ball bearing, 28 ... Static pressure bearing.

Claims (2)

A base, a movable body, a plurality of first universal joints provided on an outer edge of the movable body, a plurality of second universal joints provided on an outer edge of the base, and one end of the first universal joint a plurality of links and the other end is connected to the universal joint mounted for axial movement relative to the second universal joint, to axially move individual said link to said second universal joint In the drive mechanism of the moving body comprising means,
The second universal joint,
Before and during the ring in that will be installed rotatably in Kimotodai plane, together with the link is connected in a state of penetrating to the intermediate ring by two opposing Axis fixed to the position of the intermediate ring With the inner ring supported rotatably in the direction in which the link falls ,
Wherein the second universal joint, the mobile drive mechanism, characterized in that with two rotational degrees of freedom consisting of one rotation degree of freedom on one rotation degree of freedom and the base plane in the direction of the link from falling down. A parallel mechanism machine comprising the moving body drive mechanism according to claim 1.

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