JP2023023331A - Actuator and guide device - Google Patents

Abstract

To provide an actuator that can drive and position a slider along a curved-shape guide.SOLUTION: An actuator includes: a guide including a curved part in at least part thereof; a slider movable along the guide; a converter for converting rotary motion of a screw shaft into a linear motion of a nut and transmitting the motion to the slider; and a first support member for supporting the nut so as to be rotatable relative to the slider in accordance with a curved shape of the curved part.SELECTED DRAWING: Figure 3

Description

The present invention relates to actuators and guides.

A technique is known in which a slider is moved along an arc-shaped guide by sandwiching the arc-shaped guide from both sides with rollers provided on the slider.

In Patent Document 1, a moving body provided movably along a raceway body has a plurality of rotating bodies that roll on a plurality of rolling surfaces, and the plurality of rotating bodies contact the plurality of rolling surfaces. A motion guide device is disclosed in which respective contact points are arranged on the same straight line in a cross section perpendicular to the longitudinal direction of the track body.

In Patent Document 2, the contact angle line of the first roller and the third roller arranged in the guide is inclined downward to the right, the contact angle line of the second roller and the fourth roller is inclined upward to the right, and the second roller and a third roller are arranged above the guide, and the first roller and the fourth roller are arranged below the guide.

In Patent Document 3, a seal member movably provided on a support member includes a first contact portion that contacts the outer side of the curved portion of the guide, a first contact portion that contacts the inner side of the curved portion of the guide, and a first contact portion. A motion guide is disclosed having a contact portion and an integral second contact portion.

In Patent Document 4, the shaft having flexibility has an engaging portion formed spirally on the peripheral surface, and the engaged portion engages with the engaging portion of the shaft and engages with the engaging portion. A driving device is disclosed which is movable in a first direction along which the position relative to the case portion is fixed in a second direction orthogonal to the first direction.

Patent Document 5 discloses an arcuate ladle rail in which rollers are arranged on the concave side surface of the arcuate ladle rail so that the arcuate ladle rail can be slid while being supported from below, and grooves or protrusions are installed so that the rollers do not come off.

Japanese Patent No. 6707011 JP 2019-138366 A JP 2019-183947 A JP 2021-76125 A JP-A-50-141195

However, with the techniques disclosed in Patent Documents 1 to 5, it is difficult to drive and position the slider along the curved guide.
Accordingly, an object of one aspect of the present invention is to provide an actuator capable of driving and positioning a slider along a curved guide.
Another object of one aspect of the present invention is to provide a guide device capable of improving running stability of a slider along a curved guide.

In order to solve the above problems, an actuator according to an aspect of the present invention includes a guide having a curved portion at least in part, a slider movable along the guide, and a linear motion of a nut by rotating a screw shaft. A converting portion that converts the motion into motion and transmits the motion to the slider, and a first support member that supports the nut so as to be rotatable with respect to the slider in accordance with the curved shape of the curved portion.

Thereby, the nut can be rotated with respect to the slider according to the curved shape of the curved portion of the guide. Therefore, even if the slider is tilted according to the curved shape of the curved portion of the guide, the stability of the linear motion of the nut can be ensured. Therefore, even when the slider moves along a guide having a curved portion, the linear motion converted by the converting portion can be transmitted to the slider, and the slider can be driven and positioned along the curved guide. It becomes possible.

Further, according to the actuator of one aspect of the present invention, the first supporting member includes a first rotating shaft fixed to the nut, a first fixing member fixed to the slider, and the first fixing member. and a first bearing that rotatably supports the first rotating shaft with respect to the member.

Thereby, the slider can rotate around the first rotation shaft via the first bearing. Therefore, the first support member can support the nut rotatably with respect to the slider according to the curved shape of the curved portion of the guide.

Further, the actuator according to one aspect of the present invention further includes a second support member that supports the screw shaft so as to be rotatable with respect to the guide according to the curved shape of the curved portion.

Thereby, the screw shaft can be rotated with respect to the guide according to the curved shape of the curved portion of the guide. Therefore, even when the slider moves in the direction orthogonal to the screw axis according to the curved shape of the curved portion of the guide, the stability of the linear motion of the nut can be ensured. Therefore, even when the slider moves along a guide having a curved portion, the linear motion converted by the converting portion can be transmitted to the slider, and the slider can be driven and positioned along the curved guide. It becomes possible.

Further, according to the actuator according to the aspect of the present invention, the second support member includes a casing that accommodates the first end of the screw shaft, a second rotation shaft fixed to the casing, the guide and a second bearing that rotatably supports the second rotating shaft with respect to the second fixing member.

Thereby, the screw shaft can rotate around the second rotation shaft via the second bearing. Therefore, the second support member can support the screw shaft so as to be rotatable with respect to the guide according to the curved shape of the curved portion of the guide.

Further, the actuator according to one aspect of the present invention further includes a motor that rotates the screw shaft and a coupling that couples the motor and the screw shaft, and the motor and the coupling rotate together with the casing. It is possible.

Thereby, the motor, the coupling and the screw shaft can rotate around the second rotation shaft via the second bearing. Therefore, the second support member supports the screw shaft so as to be rotatable with respect to the guide according to the curved shape of the curved portion of the guide while ensuring the stability of the rotational motion of the screw shaft driven by the motor. can do.

Also, according to the actuator of one aspect of the present invention, the guide includes an opening through which the second end of the screw shaft escapes as the screw shaft rotates with respect to the guide.

As a result, even when the screw shaft rotates with respect to the guide according to the curved shape of the curved portion of the guide, the second end of the screw shaft does not interfere with the movement of the slider along the guide. can be prevented from colliding with the slider, and the rotational movable range of the slider can be widened.

Moreover, according to the actuator according to one aspect of the present invention, the converting portion is a ball screw, a trapezoidal screw, or a triangular screw.

Thereby, the conversion part can convert the rotary motion of the screw shaft into the linear motion of the nut. At this time, by using a ball screw as the converting portion, it is possible to reduce the driving torque, and it is possible to reduce the power consumption of the motor that rotates the screw shaft.

Further, the actuator according to one aspect of the present invention further includes eight or more rolling bearings supported by the slider and arranged to sandwich the guide from four directions.

Here, by running the slider along the guide via the rolling bearing, even if the guide has a curved portion, the slider can be moved along the guide while reducing friction with the guide.
In addition, by arranging eight or more rolling bearings so as to sandwich the guide from four directions, the holding force and rigidity of the slider can be improved regardless of the direction of the running surface of the guide. It is possible to improve the running stability, running accuracy, and positioning accuracy of the slider without limiting the installation angle of the guide.
For example, the guide can be installed upright or inverted without deteriorating the running stability, running accuracy and positioning accuracy of the slider. Therefore, for example, in the field of medical equipment using X-ray irradiation, it is possible to drive and position the slider while supporting helical scanning.

Moreover, according to the actuator of one aspect of the present invention, the rolling bearings are arranged at staggered positions with respect to the guide direction defined by the guide.

As a result, it is possible to provide alignment when the slider travels through eight or more rolling bearings, thereby suppressing deterioration in travel stability caused by machining errors of guides and sliders, mounting of rolling bearings, and the like. becomes possible.

Also, according to the actuator according to one aspect of the present invention, the slider includes a housing having two surfaces adjacent to each other on which the rolling bearings can be arranged at right angles to each other.

This allows the rolling bearings to be arranged at right angles to each other while they are adjacent. Therefore, it is possible to suppress the expansion of the space for arranging eight or more rolling bearings so as to sandwich the guide from four directions, and it is possible to improve the running stability of the slider while making the slider more compact. can.

Further, the actuator according to an aspect of the present invention includes: a crossing position of two surfaces of the housing where the rolling bearings are arranged perpendicular to each other; and the guide where the rolling bearings arranged on the two surfaces of the housing are in contact are opposite each other.

As a result, the two surfaces of the housing on which the rolling bearings are alternately arranged and the two surfaces of the guides on which the rolling bearings are alternately contacted can be adjacent to each other. A face can be provided at each end of the guide. Therefore, it is possible to improve the running stability of the slider while suppressing an increase in the slider width and the guide width.

Moreover, according to the actuator according to one aspect of the present invention, the rolling bearing is a cam follower, a ball bearing, or a roller bearing.

Accordingly, even when the guide has a curved portion, the slider can be moved along the guide while reducing friction with the guide.

Further, according to the actuator of one aspect of the present invention, the rolling bearing has a curvature on the outer peripheral surface of the outer ring.

Thereby, even when the curvature of the curved portion changes, the slider can be moved along the guide.

Moreover, according to the actuator according to one aspect of the present invention, the rolling bearing has an eccentric shaft.

As a result, preload can be applied to the rolling bearings, and the running stability and running accuracy of the slider along the guide can be improved.

Moreover, according to the actuator according to the aspect of the present invention, the curved portion has a constant curvature.

This allows the slider to move along a trajectory with a constant radius and set a virtual center.

Further, a guide device according to an aspect of the present invention includes a guide having a curved portion at least in part, a slider movable along the guide, and supported by the slider so as to sandwich the guide from four directions. and eight or more rolling bearings arranged in staggered positions with respect to the guiding direction defined by the guide.

As a result, it becomes possible to improve the holding force and rigidity of the slider regardless of the direction in which the running surface of the guide faces, and to provide alignment during running of the slider. . Therefore, it is possible to improve the running stability, running accuracy and positioning accuracy of the slider without limiting the installation angle of the guide. It is possible to suppress deterioration in running stability.

Further, a guide device according to an aspect of the present invention includes a guide having a curved portion at least in part, a slider that can move along the guide, and a slider that is supported by the slider and sandwiches the guide from four directions. eight or more rolling bearings arranged therein, the slider comprising a housing having two adjacent surfaces in which the rolling bearings can be arranged at right angles to each other.

This allows the rolling bearings to be arranged at right angles to each other while they are adjacent. Therefore, it is possible to suppress the expansion of the space for arranging eight or more rolling bearings so as to sandwich the guide from four directions, and it is possible to improve the running stability of the slider while making the slider more compact. can.

One aspect of the invention can provide an actuator capable of driving and positioning a slider along a curved guide.
Also, one aspect of the present invention can provide a guide device capable of improving the running stability of a slider along a curved guide.

FIG. 1 is a perspective view showing a configuration example of an actuator according to an embodiment. FIG. 2 is a perspective view showing a configuration example of an actuator according to the embodiment; FIG. 3 is a perspective view showing a configuration example of an actuator according to the embodiment; 4 is an enlarged perspective view showing the configuration of the opening of the guide in FIG. 2. FIG. FIG. 5 is a perspective view showing a configuration example of the actuator when the slider in FIG. 1 is at the 0 degree position. FIG. 6 is a perspective view showing a configuration example of the actuator when the slider in FIG. 1 is at the 12 degree position. FIG. 7 is a side view showing a configuration example of an actuator according to the embodiment; 8 is a cross-sectional view showing a configuration example in which the actuator is cut at the position of the slider in FIG. 7. FIG. 9 is a cross-sectional view showing a configuration in which the actuator is cut at the position of the casing in FIG. 7. FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments do not limit the present invention, and not all combinations of features described in the embodiments are essential for the configuration of the present invention. The configuration of the embodiment can be appropriately modified or changed according to the specifications of the device to which the present invention is applied and various conditions (use conditions, use environment, etc.). The technical scope of the present invention is defined by the claims and is not limited by the following individual embodiments. In addition, the drawings used in the following description may differ from the actual structure in terms of scale, shape, etc., in order to make each configuration easier to understand.

1 to 3 are perspective views showing configuration examples of the actuator according to the embodiment, FIG. 4 is an enlarged perspective view showing the configuration of the opening of the guide in FIG. 2, and FIG. 5 is a slider in FIG. FIG. 6 is a perspective view showing a configuration example of the actuator when the slider in FIG. 1 is at a position of 12 degrees; FIG. 8 is a cross-sectional view showing a structural example of the actuator cut at the position of the slider in FIG. 7, and FIG. 9 is a structural example of the actuator cut at the position of the casing shown in FIG. It is a sectional view showing. 8 is a cross-sectional view cut along line AA of FIG. 7, and FIG. 9 is a cross-sectional view cut along line BB of FIG.

In the following embodiments, the guide that guides the slider has a constant curvature in the vertical direction (tilt direction) with respect to the guide surface of the guide. It may have a constant curvature in the direction (punt direction), or it may have a constant curvature in the vertical direction with respect to the guide surface of the guide and a constant curvature in the horizontal direction with respect to the guide surface of the guide. parts may be mixed. Also, the curvature of the curved portion of the guide may be constant, or the curvature of the curved portion of the guide may vary.

1-9, an actuator 10 drives and positions a vehicle along a curved path. At this time, the actuator 10 drives and positions the moving body by using a conversion unit that converts the rotary motion of the screw shaft into the linear motion of the nut. Further, the actuator 10 supports the screw shaft and the nut so as to be rotatable in accordance with the curvilinear motion of the movable body in order to eliminate the mismatch between the curvilinear motion of the movable body and the linear motion of the nut. A gimbal mechanism, for example, can be used as a support member that supports the screw shaft and the nut so that they can rotate. This actuator 10 can drive and position an X-ray irradiation head in an arc, for example, in the field of medical equipment.

Actuator 10 includes guide 11 , slider 12 , motor 13 , coupling 14 , support members 17A, 17B, 27A, 27B and ball screw 18 .

Guide 11 guides slider 12 . The guide 11 has a curved portion at least in part. In this embodiment, the guide 11 has a constant curvature in the tilt direction with respect to the guide surface, and the case where the slider 12 is guided along an arc-shaped trajectory is taken as an example. Here, since the guide 11 has a constant curvature in the tilt direction with respect to the guide surface, the slider 12 can be moved along a track with a constant radius, and a virtual center can be set. Therefore, the actuator 10 can move the slider 12 along the circular track.

Rails 11A and 11B are provided on both sides of the guide 11 along the guiding direction of the guide 11 . A drive source for driving the slider 12 is provided on one end side of the guiding direction of the guide 11 . A stopper 21 for restricting the movement of the slider 12 is provided on the other end side of the guiding direction of the guide 11 . Further, as shown in FIG. 4, the guide surface of the guide 11 is provided with an opening 19 . Opening 19 is located between rails 11A and 11B. The opening 19 allows the end of the screw shaft 18A to escape as the screw shaft 18A rotates with respect to the guide 11, thereby widening the rotational movable range of the slider 12. As shown in FIG. Carburized steel, for example, can be used as the material of the rails 11A and 11B.

The slider 12 is movable along the guide 11 . Slider 12 is driven and positioned via ball screw 18 . At this time, the load 100 can be mounted on the slider 12 . The load 100 is, for example, an X-ray irradiation head.

Slider 12 includes housings 12A, 12B and cover 12C. The housing 12A is provided on the rail 11A side, and the housing 12B is provided on the rail 11B side. The housings 12A, 12B support eight or more cam followers JA1, JA2, JB1, JB2 so that the guide 11 is sandwiched from four directions. The cover 12C is installed so as to span over the housings 12A and 12B. A load 100 can be placed on the cover 12C.

The cam followers JA1, JA2, JB1, and JB2 are used as rolling bearings for moving the slider 12 along the guide 11. As shown in FIG. Eight or more cam followers JA1, JA2, JB1, and JB2 are arranged on the slider 12 so that the guide 11 is sandwiched from four directions. At this time, the cam followers JA1 and JA2 are arranged at staggered positions with respect to the guide direction defined by the rail 11A, and the cam followers JB1 and JB2 are arranged at staggered positions with respect to the guide direction defined by the rail 11B. be. In this embodiment, cam followers JA1, JA2, JB1, and JB2 are used as rolling bearings, but ball bearings or roller bearings may be used as the rolling bearings.

Here, as shown in FIGS. 2 and 8, in order to support the cam followers JA1, JA2, JB1, and JB2 so that the guide 11 is sandwiched from four directions, the housing 12A is provided with surfaces MA1 and MA2, and the housing 12B is provided with surfaces MA1 and MA2. are provided with MB1 and MB2. The surfaces MA1 and MA2 extend along the traveling direction of the slider 12 so as to intersect each other at right angles, and are arranged adjacent to the rail 11A side. The surfaces MB1 and MB2 extend along the traveling direction of the slider 12 so as to intersect each other at right angles, and are arranged adjacent to the rail 11B side. At this time, the curvatures of the surfaces MA1 and MA2 are set along the extending direction of the rail 11A, and the curvatures of the surfaces MB1 and MB2 are set along the extending direction of the rail 11B.

By arranging the cam follower JA1 on the surface MA1, the cam follower JA2 on the surface MA2, the cam follower JB1 on the surface MB1, and the cam follower JB2 on the surface MB2, the guide 11 is sandwiched from four directions. can support cam followers JA1, JA2, JB1, JB2 in staggered positions.

Rail 11A is provided with surfaces MA1', MA2' for receiving cam followers JA1, JA2, respectively, and rail 11B is provided with surfaces MB1', MB2' for receiving cam followers JB1, JB2, respectively.

At this time, the intersection position of the two surfaces MA1 and MA2 of the housing 12A where the cam followers JA1 and JA2 are arranged perpendicular to each other and the intersection position of the two surfaces MA1' and MA2' of the rail 11A with which the cam followers JA1 and JA2 are in contact respectively. can face each other. In addition, the intersection position of the two surfaces MB1 and MB2 of the housing 12B where the cam followers JB1 and JB2 are arranged at right angles to each other and the intersection position of the two surfaces MB1' and MB2' of the rail 11B with which the cam followers JB1 and JB2 respectively contact are , can face each other. The housing 12A may have a V-shaped protrusion at the intersection of the two surfaces MA1 and MA2 so that the ends of the rail 11A face each other. In addition, the housing 12B may have a V-shaped projection at the position where the two surfaces MB1 and MB2 intersect so that the ends of the rail 11B face each other.

At this time, on the lower surface side of the end portion of the rail 11A, a V-shaped recessed portion composed of two surfaces MA1 and MA1' capable of accommodating the cam follower JA1 is formed by tilting downward by 45°. On the upper surface side of the part, a V-shaped recess composed of two surfaces MA2, MA2' which can tilt upward by 45° and can accommodate the cam follower JA2 can be configured. In addition, on the lower surface side of the end portion of the rail 11B, a V-shaped concave portion composed of two surfaces MB1 and MB1' that is tilted downward by 45° and capable of accommodating the cam follower JB1 is formed. A V-shaped recess formed by two surfaces MB2, MB2' that can accommodate the cam follower JB2 can be configured on the upper surface side of the , inclined upward by 45°. Therefore, the cam followers JA1, JA2, JB1, and JB2 can be arranged at staggered positions such that the guides 11 are sandwiched from four directions while suppressing an increase in the arrangement space of the cam followers JA1, JA2, JB1, and JB2. .

The hardness of the outer peripheral surfaces of the cam followers JA1, JA2, JB1, and JB2 and the surfaces MA1', MA2', MB1', and MB2' of the rails 11A and 11B may be adjusted by heat treatment to suppress the progress of wear. good.

The ball screw 18 is used as a converting portion that converts rotary motion into linear motion and transmits it to the slider 12 . The ball screw 18 has a screw shaft 18A and a nut 18B. In this embodiment, the ball screw 18 is used as the converting portion, but a trapezoidal screw or a triangular screw may be used as the converting portion.

The screw shaft 18A rotates based on a rotational force generated from a driving source such as the motor 13. As shown in FIG. The nut 18B converts rotary motion of the screw shaft 18A into axial linear motion of the screw shaft 18A. A nut 18B is positioned between the housings 12A and 12B and supported by the slider 12. As shown in FIG.

The screw shaft 18A and the nut 18B each have a thread groove. The thread groove of the screw shaft 18A is spirally provided on the outer peripheral surface of the screw shaft 18A. The thread groove of the nut 18B is spirally provided on the inner peripheral surface of the nut 18B so as to face the thread groove of the screw shaft 18A. At this time, the thread groove of the screw shaft 18A and the thread groove of the nut 18B form a spiral ball rolling path between the screw shaft 18A and the nut 18B.

The material of the screw shaft 18A and the nut 18B is not particularly limited as long as it is a rigid body, and may be, for example, metal such as iron or aluminum alloy, or non-metal such as ceramic. The cross-sectional shape of the thread grooves of the screw shaft 18A and the nut 18B may be, for example, an arc or a Gothic arc.

Here, by using the ball screw 18 as the converting portion, it is possible to reduce the drive torque, and it is possible to save the power consumption of the motor 13 that rotates the screw shaft 18A.

The support members 17A and 17B support the nut 18B so as to be rotatable in the tilt direction with respect to the slider 12 according to the curved shape of the curved portion of the guide 11. As shown in FIG. As shown in FIG. 8, the support members 17A and 17B include fixed members 20A and 20B, rotary shafts 21A and 21B, and bearings UA1 and UB1. The fixed members 20A and 20B are fixed to the slider 12. As shown in FIG. The rotating shafts 21A and 21B are fixed to the nut 18B. At this time, the axial direction of the rotating shafts 21A and 21B can be set in the width direction of the guide 11. As shown in FIG. The bearings UA1 and UB1 support the rotating shafts 21A and 21B rotatably in the tilt direction with respect to the fixed members 20A and 20B. Here, the support members 17A, 17B are located between the housings 12A, 12B, and the fixing members 20A, 20B can be fixed to the rear surface of the cover 12C. As a result, the space between the housings 12A and 12B can be used to dispose the nut 18B and the support members 17A and 17B, and the slider 12 can be made compact.

Motor 13 is coupled to one end of screw shaft 18A via coupling 14 . Motor 13 is, for example, an AC servomotor. One end of the screw shaft 18A is rotatably supported around the axis of the screw shaft 18A via a bearing U0.

The support members 27A and 27B support one end of the screw shaft 18A so as to be rotatable in the tilt direction with respect to the guide 11 according to the curved shape of the curved portion of the guide 11 . As shown in FIG. 9, the support members 27A, 27B include a casing 15, fixed members 30A, 30B, rotary shafts 31A, 31B, and bearings UA2, UB2. At this time, one end of the screw shaft 18A is supported by support members 27A and 27B via the casing 15 so that the screw shaft 18A can rotate with respect to the guide 11 in the tilt direction.

Casing 15 houses bearing U0. Also, the coupling 14 and the casing 15 are housed in a container 16 and the motor 13 is supported by the container 16 . At this time, the motor 13 and the coupling 14 are rotatable together with the casing 15 via the support members 27A and 27B. Each fixing member 30A, 30B is fixed to the rails 11A, 11B. The rotating shafts 31A and 31B are fixed to the casing 15. As shown in FIG. At this time, the axial direction of the rotary shafts 31A and 31B can be set in the width direction of the guide 11. As shown in FIG. The bearings UA2 and UB2 rotatably support the rotating shafts 31A and 31B in the tilt direction with respect to the fixed members 30A and 30B.

In the above configuration, when the motor 13 rotates, the rotational motion of the motor 13 is transmitted to the screw shaft 18A via the coupling 14. As shown in FIG. The slider 12 is driven by the linear motion of the nut 18B accompanying the rotational motion of the screw shaft 18A. Further, when the rotational movement of the motor 13 is stopped, the rotational movement of the screw shaft 18A is stopped, and the translational movement of the nut 18B is stopped accordingly, whereby the slider 12 is positioned.

At this time, the nut 18B is supported by the support members 17A and 17B so as to be rotatable in the tilt direction with respect to the slider 12 according to the curved shape of the curved portion of the guide 11 in the tilt direction. Thus, the support members 17A and 17B can rotate the nut 18B in the tilt direction with respect to the slider 12 according to the curved shape of the curved portion of the guide 11 in the tilt direction. Therefore, the support members 17A and 17B can eliminate the mismatch between the curved motion of the slider 12 in the tilt direction and the linear motion of the nut 18B. Even when the slider 12 is tilted in the tilt direction, the stability of the linear motion of the nut 18B can be ensured. Therefore, even when the slider 12 moves along the guide 12 having a curved portion, the linear motion converted by the ball screw 18 can be transmitted to the slider 12, so that the slider moves along the curved guide 11. Twelve drives and positioning are possible.

The screw shaft 18A is supported by support members 27A and 27B so as to be rotatable in the tilt direction with respect to the guide 11 according to the curved shape of the curved portion of the guide 11 in the tilt direction. Accordingly, the screw shaft 18A can be rotated in the tilt direction with respect to the guide 11 according to the curved shape of the curved portion of the guide 11 in the tilt direction. Therefore, even when the slider 12 moves in the direction orthogonal to the screw shaft 18A according to the curved shape of the curved portion of the guide 11 in the tilt direction, the stability of the linear movement of the nut 18B can be ensured. Therefore, even when the slider 12 moves along the guide 11 having a curved portion, the linear motion converted by the ball screw 18 can be transmitted to the slider 12, so that the slider moves along the curved guide 11. Twelve drives and positioning are possible.

When the slider 12 is driven, the cam followers JA1 and JA2 run on the surfaces MA1 and MA2 of the rail 11A, and the cam followers JB1 and JB2 run on the surfaces MB1 and MB2 of the rail 11B. As a result, the slider 12 can move in a curved line while being guided by the guide 11 while reducing friction with the guide 11 .

At this time, by arranging eight or more cam followers JA1, JA2, JB1, and JB2 so as to sandwich the guide 11 from four directions, the slider 12 can be moved even when the running surface of the guide 11 faces in any direction. The holding force and rigidity of the slider 12 can be improved, and the running stability, running accuracy, and positioning accuracy of the slider 12 can be improved without limiting the installation angle of the guide 11 .
For example, the guide 11 can be installed upright or inverted without reducing the running stability, running accuracy, and positioning accuracy of the slider 12 . Therefore, for example, in the field of medical equipment using X-ray irradiation, the slider 12 can be driven and positioned while supporting helical scanning.

The cam followers JA1, JA2, JB1, and JB2 are arranged at staggered positions with respect to the guiding direction defined by the guide 11. As shown in FIG. As a result, it is possible to provide alignment when the slider 12 travels through eight or more cam followers JA1, JA2, JB1, and JB2. It is possible to suppress deterioration in running stability due to the installation of the

The housing 12A has two adjacent surfaces MA1 and MA2 on which the cam followers JA1 and JA2 can be arranged at right angles to each other, and the housing 12B has two adjacent surfaces on which the cam followers JB1 and JB2 can be arranged at right angles to each other. It has MB1 and MB2. As a result, the cam followers JA1 and JA2 can be arranged at right angles to alternate positions while adjoining the cam followers JA1 and JA2 in an oblique direction on the rail 11A side. It is possible to arrange the cam followers JB1 and JB2 at alternate positions at right angles while adjoining them in an oblique direction. Therefore, it is possible to suppress the expansion of the space for arranging eight or more cam followers JA1, JA2, JB1, and JB2 at alternate positions so as to sandwich the guide 11 from four directions, and the slider 12 can be made compact. At the same time, the running stability of the slider 12 can be improved.

Further, the intersection position of the two surfaces MA1 and MA2 of the housing 12A and the intersection position of the two surfaces MA1' and MA2' of the rail 11A are opposed to each other, and the intersection position of the two surfaces MB1 and MB2 of the housing 12B and the rail The intersection positions of the two planes MB1' and MB2' of 11B can face each other. This causes the two faces MA1, MA2 of the housing 12A and the two faces MA1', MA2' of the rail 11A to be adjacent to each other, and the two faces MB1, MB2 of the housing 12B and the two faces MB1' of the rail 11B. MB2' can be adjacent to each other. For this reason, eight or more cam followers JA1, JA2, JB1, and JB2 are arranged in staggered positions, and four surfaces MA1', MA2', MB1', and MB2' of the guide 11 for sandwiching the guide 11 from four directions are arranged. can be provided at both ends of the guide 11 . Therefore, it is possible to improve the running stability of the slider 12 while suppressing an increase in the slider width and the guide width.

Further, as the slider 12 moves from the position of 0 degrees in FIG. 5 to the position of 12 degrees in FIG. 6, the crossing angle between the guide 11 and the screw shaft 18A in the tilt direction increases. When the slider 12 moves further away from the motor 13, the crossing angle between the guide 11 and the screw shaft 18A in the tilt direction further increases, and the tip of the screw shaft 18A reaches the opening 19 as shown in FIG. enter. As a result, it is possible to prevent the movement of the slider 12 from being restricted due to an increase in the crossing angle between the guide 11 and the screw shaft 18A in the tilt direction, and the rotational movable range of the slider 12 can be widened.

Each cam follower JA1, JA2, JB1, JB2 may have an eccentric shaft. As a result, preload can be applied to each of the cam followers JA1, JA2, JB1, and JB2, and the running stability and running accuracy of the slider 12 along the guide 11 can be improved. It is not necessary for all of the eight or more cam followers provided on the slider 12 to have eccentric shafts, and some of the cam followers provided on the slider 12 may have eccentric shafts.

Further, each of the cam followers JA1, JA2, JB1, and JB2 may have a curvature on the outer peripheral surface of the outer ring. Thereby, the actuator 10 can move the slider 12 along the guide 11 even when the curvature of the curved portion of the guide 11 changes.

The mounting positions of the cam followers JA1, JA2, JB1, and JB2 may be varied using springs or the like. Thereby, even when the curvature of the curved portion of the guide 11 is not constant, the slider 12 can be driven along the guide 11 .

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace part of the configuration of each embodiment with another configuration.

Reference Signs List 10 Actuator 11 Guide 11A, 11B Rail 12 Slider 12A, 12B Housing 12C Cover 13 Motor 14 Coupling 15 Casing 16 Container 17A, 17B, 27A, 27B Support member 18 Ball screw 18A Screw shaft 18B Nut 19 Opening 20A, 20B, 30A, 30B Fixing member 21A, 21B, 31A, 31B Rotating shaft JA1, JA2, JB1, JB2 Cam follower MA1, MA1', MA2, MA2', MB1, MB1', MB2, MB2' surface, 21 stopper, U0, UA1, UB1, UA2, UB2 bearing

Claims (17)

a guide having a curved portion at least partially;
a slider movable along the guide;
a conversion unit that converts the rotational motion of the screw shaft into linear motion of the nut and transmits the motion to the slider;
and a first support member that supports the nut so as to be rotatable with respect to the slider according to the curved shape of the curved portion. The first support member is
a first rotating shaft fixed to the nut;
a first fixing member fixed to the slider;
2. The actuator according to claim 1, further comprising a first bearing that rotatably supports said first rotating shaft with respect to said first fixed member. 3. The actuator according to claim 1, further comprising a second support member that supports the screw shaft so as to be rotatable with respect to the guide according to the curved shape of the curved portion. The second support member is
a casing housing the first end of the screw shaft;
a second rotating shaft fixed to the casing;
a second fixing member fixed to the guide;
4. The actuator according to claim 3, further comprising a second bearing that rotatably supports the second rotating shaft with respect to the second fixing member. a motor that rotates the screw shaft;
further comprising a coupling that couples the motor and the screw shaft,
5. An actuator according to claim 4, wherein said motor and said coupling are rotatable together with said casing. 6. The actuator according to any one of claims 3 to 5, wherein the guide has an opening through which the second end of the screw shaft escapes as the screw shaft rotates with respect to the guide. 7. The actuator according to any one of claims 1 to 6, wherein the converting portion is a ball screw, a trapezoidal screw or a triangular screw. 8. The actuator according to any one of claims 1 to 7, further comprising eight or more rolling bearings supported by the slider and arranged to sandwich the guide from four directions. 9. The actuator according to claim 8, wherein the rolling bearings are arranged in staggered positions with respect to the guide direction defined by the guide. 10. Actuator according to claim 8 or 9, characterized in that the slider comprises a housing having two adjacent surfaces on which the rolling bearings can be arranged at right angles to each other. The intersection of the two surfaces of the housing where the rolling bearings are arranged perpendicular to each other and the intersection of the two surfaces of the guide where the rolling bearings arranged on the two surfaces of the housing are in contact are opposed to each other. 11. The actuator according to claim 10, characterized in that: 12. An actuator according to any one of claims 8 to 11, wherein said rolling bearing is a cam follower, ball bearing or roller bearing. 13. The actuator according to any one of claims 8 to 12, wherein the rolling bearing has a curvature on the outer peripheral surface of the outer ring. 14. An actuator according to any one of claims 8 to 13, wherein said rolling bearing comprises an eccentric shaft. 15. The actuator according to any one of claims 1 to 14, wherein said curved portion has a constant curvature. a guide having a curved portion at least partially;
a slider movable along the guide;
A guide characterized by comprising eight or more rolling bearings supported by the slider and arranged in staggered positions with respect to the guiding direction defined by the guide so as to sandwich the guide from four directions. Device. a guide having a curved portion at least partially;
a slider movable along the guide;
Eight or more rolling bearings supported by the slider and arranged to sandwich the guide from four directions,
Guiding device, characterized in that said slider comprises a housing having two adjacent faces in which said rolling bearings can be arranged at right angles to each other.

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