JP2008298193A - Uniaxial actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a uniaxial actuator attached with a support unit, without substantially causing an error in an installation position. <P>SOLUTION: A support unit 17 of the uniaxial actuator has two projection parts 34 and 34 of a shape engaging with a rolling element rolling groove 11a of a guide rail 11, in a position opposed to the rolling element rolling groove 11a of the guide rail 11. These two projection parts 34 and 34 are respectively fitted to the rolling element rolling grooves 11a and 11a of both side walls 32 and 32 of the guide rail 11, and after positioning the installation position of the support unit 17, the support unit 17 is fixed to an end surface of the guide rail 11 by a bolt 25. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a uniaxial actuator formed by integrating a linear motion guide bearing and a screw type feeding device.

  As a conventional uniaxial actuator, for example, a guide rail having a concave cross section and having rolling element rolling grooves extending in the axial direction on the opposite inner side surfaces, and an axial direction substantially at the center in the width direction of the guide rail. A screw shaft disposed in parallel to the guide rail, a slider having a rolling element rolling groove facing the rolling element rolling groove of the guide rail, screwed to the screw shaft via a number of balls, and a guide rail 2. Description of the Related Art There are known devices including two support units that are respectively attached to both ends and rotatably support a screw shaft.

  On both side surfaces of the slider, rolling element rolling grooves that face the rolling element rolling grooves of the guide rail are formed, and a rolling element rolling path is formed by both rolling element rolling grooves. In addition, rolling element return paths each including a through hole penetrating in the axial direction in parallel with the rolling element rolling grooves on both sides are formed inside the slider. Furthermore, the end caps attached to both ends in the axial direction of the slider are formed with curved paths that connect the rolling element rolling paths and the corresponding rolling element return paths. A rolling element circulation path is formed by the rolling element rolling path, the rolling element return path, and the curved paths at both ends, and a large number of rolling elements for linear motion guidance ( Ball) is loaded to roll freely.

Further, the support unit is provided with a through hole, and a rolling bearing is fitted to the inner peripheral surface of the through hole. Then, the screw shaft is inserted and fitted into the inner diameter portion of the rolling bearing, and the screw shaft can be rotated by the rolling bearing.
When the screw shaft is rotated, the slider engaged with the screw shaft moves smoothly in the axial direction through the rolling of the rolling element in the rolling element rolling path. During this movement, the rolling element for linear motion guidance is infinitely circulated while rolling in the rolling element circulation path.
In such a conventional uniaxial actuator, the support unit is attached to both end faces of the guide rail. That is, a tapped hole is provided in the end surface of the guide rail, and the support unit is attached by a bolt.
JP 2003-120820 A JP-A-11-108141

  In order for the single-axis actuator to be driven smoothly, the center position of the screw shaft needs to be aligned with high accuracy. Therefore, even when the support unit that supports the screw shaft is attached to the guide rail, Accurate alignment was necessary. That is, it is necessary to align the positions of the through holes provided in the support unit so that the center of the screw shaft is at a predetermined position.

However, since there is no reference for alignment, it is not easy to perform highly accurate alignment, and there is a possibility that an error occurs in the mounting position of the support unit.
Accordingly, an object of the present invention is to solve the above-described problems of the conventional single-axis actuator and provide a single-axis actuator to which a support unit is attached with almost no error in the attachment position.

  In order to solve the above problems, the present invention has the following configuration. That is, the uniaxial actuator according to claim 1 of the present invention comprises a strip-like bottom plate extending in the axial direction and side walls vertically provided from both side portions of the bottom plate. A guide rail having a substantially concave cross section formed in a groove in the axial direction, a screw shaft disposed on the inner side of the guide rail in parallel to the axial direction and having a helical thread groove on the outer peripheral surface, and the guide A support unit that is attached to a rail and rotatably supports the screw shaft, and a slider that has a rolling element rolling groove facing the rolling element rolling groove of the guide rail and that is screwed to the screw shaft. A plurality of rolling elements interposed between the rolling element rolling grooves of the guide rail and the rolling element rolling grooves of the slider, the slider rolling the rolling elements. Through the guide rail in the axial direction In the uniaxial actuator that is enabled, the support unit has a convex portion that has a shape that engages with the rolling element rolling groove of the guide rail, and at least one rolling element rolling member on both side walls of the guide rail. It is attached to the said guide rail, engaging the said convex part with a moving groove.

  According to a second aspect of the present invention, there is provided a uniaxial actuator comprising: a strip-like bottom plate extending in the axial direction; and side walls erected vertically from both side portions of the bottom plate. A guide rail having a substantially concave cross section formed in a groove in the axial direction, a screw shaft disposed on the inner side of the guide rail in parallel to the axial direction and having a helical thread groove on the outer peripheral surface, and the guide A support unit that is attached to a rail and rotatably supports the screw shaft, and a slider that has a rolling element rolling groove facing the rolling element rolling groove of the guide rail and that is screwed to the screw shaft. A plurality of rolling elements interposed between the rolling element rolling grooves of the guide rail and the rolling element rolling grooves of the slider, the slider rolling the rolling elements. Can be moved in the axial direction along the guide rail In the uniaxial actuator, the support unit has a plurality of protrusions shaped to engage with the rolling element rolling grooves of the guide rail, and the rolling unit rolling grooves on both side walls of the guide rail have the above-mentioned It is attached to the said guide rail, engaging a convex part, respectively.

  Furthermore, the uniaxial actuator according to claim 3 of the present invention is the uniaxial actuator according to claim 1 or 2, wherein the support unit is arranged inside the guide rail, and a part thereof contacts the support unit. A fixing member whose other part is in contact with the side wall of the guide rail is arranged on the side of the side wall of the guide rail, and the side wall is sandwiched between the support unit and the fixing member. The support unit is attached to the guide rail by fixing a contact portion with the fixing member.

  Further, a uniaxial actuator according to a fourth aspect of the present invention is the uniaxial actuator according to the first or second aspect, wherein the support unit is arranged inside the guide rail, and an upper end of a side wall of the guide rail is arranged. The support unit is attached to the guide rail by providing the support unit with a fixing arm that extends to the lower part of the side wall and fixing the guide rail and the fixing arm at the lower part of the side wall. It is a feature.

Furthermore, the uniaxial actuator according to claim 5 of the present invention is the uniaxial actuator according to any one of claims 1 to 4, wherein the convex portion is at least on a groove surface of the rolling element rolling groove of the guide rail. Contact is made at two points, and the position of the contact point on the groove surface is substantially the same as the position of the contact point between the rolling element and the rolling element rolling groove of the guide rail on the groove surface. To do.
Furthermore, the uniaxial actuator according to claim 6 of the present invention is the uniaxial actuator according to any one of claims 1 to 5, wherein the slider is provided with a through-hole through which the screw shaft is inserted. A screw groove facing the screw groove of the screw shaft is formed on the inner surface of the through hole by machining.

  The uniaxial actuator of the present invention can be driven smoothly because there is almost no error in the attachment position and the support unit is attached.

[First embodiment]
FIG. 1 is a partially broken perspective view illustrating a first embodiment of a uniaxial actuator according to the present invention. FIG. 2 is a cross-sectional view of the uniaxial actuator of FIG. 1 cut along a plane perpendicular to the axial direction.
The guide rail 11 extending in the axial direction includes a strip-shaped bottom plate 31 and side walls 32 and 32 standing vertically from both side portions of the bottom plate 31, and a cross section broken at a plane perpendicular to the axial direction is substantially concave. I am doing. In addition, a screw shaft 13 having an outer peripheral surface with a screw groove 13a having a circular arc cross section that is continuous in a spiral shape is disposed in the center in the width direction inside the guide rail 11 in parallel to the axial direction. The screw shaft 13 is supported by support units 17 and 17 attached to both ends of the guide rail 11 so as to be rotatable in both forward and reverse directions.

  Further, a rectangular parallelepiped slider 12 is disposed inside the guide rail 11 and is screwed to the screw shaft 13 via a large number of rolling elements 14. That is, the slider 12 is provided with a through-hole through which the screw shaft 13 is inserted, and a screw groove 12a having a circular arc shape that is continuous in a spiral shape is formed on the inner peripheral surface of the through-hole. The screw groove 12a faces the screw groove 13a of the screw shaft 13, and the first rolling element rolling path 21 having a substantially circular cross section formed by both the screw grooves 12a and 13a is made of, for example, a steel ball. A large number of rolling elements 14 are loaded so as to roll freely. The slider 12 includes a slider main body 12A and end caps 12B and 12B that are detachably attached to both ends in the axial direction.

  Furthermore, the opposing inner side surfaces of the both side walls 32, 32 of the guide rail 11 are provided with rolling element rolling grooves 11a, 11a having a substantially arc-shaped cross section extending in the axial direction. Rolling element rolling grooves 12b and 12b having a substantially arc-shaped cross section facing the rolling element rolling grooves 11a and 11a of the guide rail 11 are provided, and the rolling element rolling grooves 11a and the slider 12 of the opposing guide rail 11 are opposed to each other. The rolling element rolling grooves 12b form second rolling element rolling paths 22 and 22 having a substantially circular cross section. In addition, the 2nd rolling element rolling path 22 is not limited to one line | wire on one side, and may provide two or more lines.

  Furthermore, rolling element return paths 23 and 23 each having a circular cross-sectional through-hole penetrating in the axial direction in parallel with the second rolling element rolling path 22 are formed inside the slider 12. Further, the end caps 12B and 12B provided at both ends in the axial direction of the slider 12 are formed with curved paths (not shown) that connect the second rolling element rolling path 22 and the corresponding rolling element return path 23 to each other. The second rolling element rolling path 22, the rolling element return path 23, and the curved path at both ends form a rolling element circulation path. In the circulation path of the rolling elements, a large number of rolling elements 15 made of, for example, steel balls are loaded so as to freely roll.

Furthermore, the support units 17 and 17 are provided with through holes, and a rolling bearing (not shown) is fitted to the inner peripheral surface of the through holes. The screw shaft 13 is inserted and fitted into the inner diameter portion of the rolling bearing, and the screw shaft 13 can be rotated by the rolling bearing.
When the screw shaft 13 is rotated, the slider 12 engaged with the screw shaft 13 smoothly moves in the axial direction along the guide rail 11 through the rolling of the rolling element 15 in the second rolling element rolling path 22. When the slider 12 moves, the rolling elements 15 in the second rolling element rolling path 22 circulate infinitely while rolling on the circulation path.

  In such a uniaxial actuator of this embodiment, the support units 17 and 17 are attached to both end surfaces of the guide rail 11. That is, a tapped hole is provided in the end surface of the guide rail 11, and the support units 17 and 17 are attached by the bolt 25. When the support units 17 and 17 are attached, the alignment is performed as follows.

  As can be seen from FIG. 3, which is a partial plan view of the single-axis actuator, and FIG. 4, which is a sectional view taken along the line AA, the support unit 17 is located at a position facing the rolling element rolling groove 11 a of the guide rail 11. Two protrusions 34 and 34 (that is, protrusions having a substantially semicircular cross section) that are engaged with the rolling element rolling groove 11a. Then, these two convex portions 34 and 34 are fitted into the rolling element rolling grooves 11a and 11a of the both side walls 32 and 32 of the guide rail 11, respectively, and the mounting position of the support unit 17 is aligned. The unit 17 is fixed to the end surface of the guide rail 11 with bolts 25.

  As described above, since the positioning of the mounting position of the support unit 17 is performed based on the rolling element rolling groove 11a of the guide rail 11, the positioning of the support unit 17 is highly accurate and there is almost no error in the mounting position. . Therefore, since the center position of the screw shaft 13 supported by the support unit 17 is aligned with high accuracy, the uniaxial actuator can be driven very smoothly.

  In the present embodiment, the two convex portions 34 are provided and engaged with the rolling element rolling grooves 11a on both sides, but the number of the convex portions 34 may be one. If one protrusion 34 is engaged with the rolling element rolling groove 11a on one side, the posture of the support unit 17 can be prevented from being inclined in the pitching direction and the yawing direction. However, in order to suppress tilting in the rolling direction in addition to the pitching direction and the yawing direction, it is preferable to provide two convex portions 34 and engage with the rolling element rolling grooves 11a on both sides.

  Further, the rolling element 15 is in contact with the groove surface of the rolling element rolling groove 11a of the guide rail 11 at two points, but the convex portion 34 is also in contact with the groove surface at two points like the rolling element 15. Preferably it is. The position of the contact point C on the groove surface (as shown in FIG. 5, the position on the groove surface when the surface is broken in a plane orthogonal to the axial direction) is the rolling element rolling of the rolling element 15 and the guide rail 11. It is preferable that the contact point with the groove 11a is substantially the same as the position on the groove surface.

The slider 12 is also positioned by the rolling element rolling groove 11a of the guide rail 11. Strictly speaking, the slider 12 is positioned by the position of the contact point between the rolling element 15 and the rolling element rolling groove 11a. become. Since the screw shaft 13 is integrated with the slider 12, the positioning of the support unit 17 that determines the center position of the screw shaft 13 is also based on the position of the contact point between the rolling element 15 and the rolling element rolling groove 11a. It is preferable to perform alignment with higher accuracy.
Furthermore, the shape of the convex portion 34 is preferably a shape that follows the groove surface of the rolling element rolling groove 11a as shown in FIG. 4, but if it can be aligned by engaging with the rolling element rolling groove 11a. The shape may not be along the groove surface of the rolling element rolling groove 11a. For example, the cross-sectional polygonal shape may be sufficient.

  Further, when the tapped hole is machined in the end surface of the guide rail 11, the outer side surface of the one side wall 32 of the guide rail 11 is set as the reference mounting surface of the uniaxial actuator, and machining is performed accordingly. In the uniaxial actuator manufactured as described above, the outer surface of the opposite side wall 32 cannot be used as the attachment reference surface. If the support unit 17 on the fixed side and the support unit 17 on the support side are replaced in the opposite positions and attached, the above problem can be solved. However, both support units 17 have through holes or the like into which the rolling bearings are fitted, respectively. Therefore, it was not possible to attach with high accuracy even if the position was simply changed. In the case of the uniaxial actuator of this embodiment, since both support units 17 are processed with reference to the rolling element rolling groove 11a of the guide rail 11, the support unit 17 on the fixed side and the support unit 17 on the support side are reversed. Even if the position is changed, it can be attached with high accuracy.

  Further, the thread groove 12 a formed on the inner peripheral surface of the through hole of the slider 12 is not provided by fitting a cylindrical member having a thread groove formed on the inner peripheral surface thereof into the through hole of the slider 12. Is preferably formed directly on the inner circumferential surface. That is, a separately manufactured ball screw can be incorporated into the through hole of the slider 12 to obtain a uniaxial actuator. However, in order to align the center position of the screw shaft 13 with high accuracy, It is preferable to form the rolling element rolling groove 12b and the thread groove 12a by machining. For the same reason, when manufacturing the support unit 17, it is preferable to form the through hole and the contact surface of the convex portion 34 with the rolling element rolling groove 11 a by machining.

[Second Embodiment]
FIG. 6 is a plan view for explaining a second embodiment of the uniaxial actuator according to the present invention. FIG. 7 is a cross-sectional view of the uniaxial actuator of FIG. 6 viewed from the axial direction. In addition, since the structure and effect | action of the uniaxial actuator of 2nd embodiment are substantially the same as 1st embodiment, only a different part is demonstrated and description of the same part is abbreviate | omitted. 6 and 7, the same reference numerals as those in FIGS. 1 to 4 are given to the same or corresponding parts as those in FIGS.
The support unit 17 is arranged not on the end face of the guide rail 11 but on the inside of the guide rail 11 like the slider 12, and is attached to the guide rail 11 using a fixing member 40 as shown in FIGS. ing. Details will be described below.

  Two convex portions 34 projecting from both side surfaces of the support unit 17 are fitted in the rolling element rolling grooves 11a and 11a of the side walls 32 and 32 of the guide rail 11, respectively. Alignment has been made. A plate-like fixing member 40 bent in a crank shape is disposed on the side of the side wall 32 of the guide rail 11, and a part of the fixing member 40 contacts the side surface of the support unit 17, and the fixing member The other part of 40 is in contact with the outer surface of the side wall 32 of the guide rail 11. A contact portion between the support unit 17 and the fixing member 40 is fixed by a bolt 25. Thus, the support unit 17 is attached to the guide rail 11 by sandwiching the side wall 32 of the guide rail 11 between the support unit 17 and the fixing member 40.

  If the support unit 17 is attached using the fixing member 40 in this way, it is not necessary to process a tapped hole in the guide rail 11. Thus, the cost of the single axis actuator can be reduced. Further, since the frictional engagement is performed, for example, when an overload exceeding a static load rating is applied such that the ball screw part is destroyed, the fastening part may slip and the ball screw part may be prevented from being destroyed. Further, the guide rail 11 receives a stress in a direction that causes the upper end portion of the side wall 32 to open outward due to a load or moment applied to the slider 12. In particular, both ends of the guide rail 11 have a weak resistance against such stress. In the uniaxial actuator of the present embodiment, the both side walls 32 of the guide rail 11 are pressed from the outside by the fixing member 40, so that the deformation that the upper end portion of the side wall 32 opens outward is suppressed.

  Furthermore, when shortening the length by cutting the uniaxial actuator, if it is a conventional uniaxial actuator, it is necessary to post-process after cutting the tap hole for attaching the support unit to the end surface of the guide rail. The post-processing of the tapped holes was not easy because of the increased hardness. On the other hand, in the case of the uniaxial actuator of the present embodiment, the support unit 17 is attached using the fixing member 40, so that it is not necessary to perform post-processing of the tap hole. Therefore, the specification change of the single axis actuator can be easily performed.

[Third embodiment]
FIG. 8 is a front view seen from the axial direction for explaining a third embodiment of the single-axis actuator according to the present invention. In addition, since the structure and effect | action of the uniaxial actuator of 3rd embodiment are substantially the same as 1st embodiment, only a different part is demonstrated and description of the same part is abbreviate | omitted. Further, in FIG. 8, the same reference numerals as those in FIGS.
The support unit 17 is arranged not on the end face of the guide rail 11 but on the inner side of the guide rail 11, and is attached to the guide rail 11 using a fixing arm 41 as shown in FIG. Details will be described below.

  Two convex portions 34 projecting from both side surfaces of the support unit 17 are fitted into the rolling element rolling grooves 11 a and 11 a of the side walls 32 and 32 of the guide rail 11, respectively. Thereby, the attachment position of the support unit 17 is aligned. Further, the support unit 17 is provided with a fixing arm portion 41 that protrudes horizontally from the upper portion of the support unit 17, straddles the upper end of the side wall 32, and extends to the lower portion of the side wall 32 along the outer surface of the side wall 32. And the front-end | tip of the arm part 41 for fixation and the lower part of the side wall 32 of the guide rail 11 are adhere | attached with the volt | bolt 25. As shown in FIG.

Thus, since the support unit 17 and the guide rail 11 are fixed without using another member, the fastening reliability is high. Moreover, since the lower part of the side wall 32 of the guide rail 11 is separated from the rolling element rolling groove 11a, the hardness is relatively low and it is easy to process a tapped hole. Furthermore, an external force is applied to the center of the screw shaft 13, but this external force can be received by the convex portion 34 of the support unit 17 that abuts the rolling element rolling groove 11a, so that it is at a position away from the rolling element rolling groove 11a. The stress applied to a certain bolt 25 can be reduced.
Further, as in the case of the second embodiment, the both side walls 32 of the guide rail 11 are pressed from the outside by the fixing arm portion 41, so that the deformation such that the upper end portion of the side wall 32 opens outward is suppressed. .

1 is a perspective view of a first embodiment of a uniaxial actuator according to the present invention. It is sectional drawing of the uniaxial actuator of FIG. FIG. 2 is a partial plan view of the uniaxial actuator of FIG. 1. It is AA sectional drawing of the uniaxial actuator of FIG. It is sectional drawing explaining the position of the contact point of the convex part of a support unit, and the rolling element rolling groove of a guide rail. It is a top view of a second embodiment of a uniaxial actuator according to the present invention. It is the front view which looked at the uniaxial actuator of FIG. 6 from the axial direction. It is a front view of 3rd embodiment of the uniaxial actuator which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Guide rail 11a Rolling body rolling groove 12 Slider 12b Rolling body rolling groove 13 Screw shaft 13a Screw groove 15 Rolling body 17 Support unit 31 Bottom plate 32 Side wall 34 Convex part 40 Fixing member 41 Fixing arm part
C Contact point

Claims (6)

It is composed of a belt-like bottom plate extending in the axial direction and side walls standing upright from both side portions of the bottom plate. A guide rail, a screw shaft disposed in parallel to the axial direction inside the guide rail and having a helical thread groove on an outer peripheral surface, and a support attached to the guide rail and rotatably supporting the screw shaft A unit, a slider having a rolling element rolling groove facing the rolling element rolling groove of the guide rail and screwed to the screw shaft, and the rolling element rolling groove of the guide rail facing the rolling rail and the slider. A plurality of rolling elements interposed between the rolling element rolling grooves and the rolling element, and the slider is movable in the axial direction along the guide rail via the rolling of the rolling element. In a single axis actuator
The support unit has a convex portion that is configured to engage with the rolling element rolling groove of the guide rail, and the convex portion is engaged with at least one rolling element rolling groove of both side walls of the guide rail. A single-axis actuator that is attached to the guide rail while being combined. It is composed of a strip-shaped bottom plate extending in the axial direction and side walls erected vertically from both sides of the bottom plate, and rolling element rolling grooves are respectively formed in the inner surface of the both side walls in a substantially concave shape in cross section. A guide rail, a screw shaft disposed in parallel to the axial direction inside the guide rail and having a helical thread groove on an outer peripheral surface, and a support attached to the guide rail and rotatably supporting the screw shaft A unit, a slider having a rolling element rolling groove opposed to the rolling element rolling groove of the guide rail, screwed to the screw shaft, the rolling element rolling groove of the guide rail facing the rolling rail, and the slider. A plurality of rolling elements interposed between the rolling element rolling grooves and the rolling element, and the slider is movable in the axial direction along the guide rail via the rolling of the rolling element. In a single axis actuator
The support unit has a plurality of convex portions that are configured to engage with the rolling element rolling grooves of the guide rail, and the convex portions are respectively engaged with the rolling element rolling grooves on both side walls of the guide rail. However, the uniaxial actuator is attached to the guide rail.   The support unit is arranged on the inner side of the guide rail, and a fixing member whose part is in contact with the support unit and whose other part is in contact with the side wall of the guide rail is arranged on the side of the side wall of the guide rail. The support unit is attached to the guide rail by sandwiching a side wall between the support unit and the fixing member and fixing a contact portion between the support unit and the fixing member. The uniaxial actuator according to claim 1 or 2.   The support unit is disposed on the inner side of the guide rail, and the support unit is provided with a fixing arm portion that extends over the upper end of the side wall of the guide rail to the lower portion of the side wall, and the guide rail, the fixing arm portion, The uniaxial actuator according to claim 1 or 2, wherein the support unit is attached to the guide rail by fixing the at a lower portion of the side wall.   The convex portion is in contact with the groove surface of the rolling element rolling groove of the guide rail at at least two points, and the position of the contact point on the groove surface is the rolling element rolling of the rolling element and the guide rail. The uniaxial actuator according to any one of claims 1 to 4, wherein the position of the contact point with the groove is substantially the same as the position on the groove surface.   2. The slider is provided with a through-hole through which the screw shaft is inserted, and a screw groove facing the screw groove of the screw shaft is formed in an inner surface of the through-hole by machining. The uniaxial actuator as described in any one of -5.

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