JP2004108474A - Linear motion guide device - Google Patents

Abstract

A linear motion guide device having excellent durability is provided.
A guide rail, a slider mounted on the guide rail so as to be movable in an axial direction, a plurality of rolling elements rotatably mounted in rolling element rolling paths, and rolling elements. Rolling element return path 16 for feeding the rolling element 3 from the end point to the starting point of the rolling element rolling path 14, and a rolling element scooping section 17 for guiding the rolling element 3 located at the end point of the rolling element rolling path 14 into the rolling element return path 16. The rolling element return path 16 is constituted by the straight path 13 and the curved path 15, and the slider 2 is constituted by the bearing block 2A and the end cap 2B. The curved path 15 has a curved shape as a whole including three arcs having different radii of curvature and centers of curvature, and the end of the curved path 15 that is continuous with the rolling element scooping portion 17 is a curved path 15. Have a radius of curvature larger than an arc having a diameter equal to the linear distance between both ends.
[Selection diagram] FIG.

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a linear motion guide device having excellent durability.
[0002]
[Prior art]
FIG. 13 is a perspective view, FIG. 14 is a front view (however, end caps are omitted), and a cross-sectional view taken along line AA of FIG. This will be described with reference to FIG.
This linear motion guide device includes a guide rail 101 extending in the axial direction and having a substantially rectangular cross section, and a slider 102 having a substantially U-shaped cross section attached to the guide rail 101. Both side surfaces 101a of the guide rail 101 are provided. , 101a, a total of four rows of rolling element rolling grooves 110, 110, 110, 110 are formed in the axial direction.
[0003]
The slider 102 is composed of a bearing block 102A and end caps 102B, 102B attached to both ends in the axial direction. Further, both ends of the slider 102 (end faces of the end caps 102B) are provided. Side seals 105, 105 for sealing an opening of a gap between the guide rail 101 and the slider 102 are mounted.
[0004]
Further, the bearing block 102A has rolling element rolling grooves 111, 111, 111, 111 opposed to the rolling element rolling grooves 110, 110, 110, 110 of the guide rail 101 on the inner side surfaces of the both sleeves 106, 106. And has straight paths 113, 113, 113, 113 that penetrate the thick portions of the sleeves 106, 106 in the axial direction (see FIG. 14). The rolling element rolling paths 114, 114, 114, 114 are formed from the opposing rolling element rolling grooves 110, 110, 110, 110, 111, 111, 111, 111.
[0005]
On the other hand, as shown in FIG. 15, the end caps 102B, 102B have a curved path 115 that connects the rolling element rolling path 114 and a linear path 113 parallel thereto. The curved paths 115 at both ends constitute a rolling element return path 116 for feeding a rolling element 103 described later from an end point to a starting point of the rolling element rolling path 114.
[0006]
A rolling element circulation path is formed by the rolling element rolling path 114 and the rolling element return path 116, and a number of rolling elements 103 made of, for example, steel balls are loaded in the rolling element circulation path.
The slider 102 mounted on the guide rail 101 smoothly moves along the guide rail 101 through the rolling of the rolling element 103 in the rolling element rolling path 114, and during the movement, the rolling element 103 Endlessly circulates while rolling in the rolling element circulation path.
[0007]
In such a conventional linear motion guide device, the rolling element 103 is moved from the rolling element rolling path 114 (loading section) to the curved path 115 (non-loading section) by the rolling element scooping portion 117 provided in the end cap 102B. And sent to a straight path 113. The rolling element 103 sent to the straight path 113 is returned to the rolling element rolling path 114 via the curved path 115 on the opposite side.
[0008]
[Problems to be solved by the invention]
As can be seen from FIG. 15, since the curved path 115 has an R shape (an arc shape whose diameter is the linear distance between both ends of the curved path 115), when the rolling element 103 passes through the curved path 115, the curved path 115 is formed. Is subjected to centrifugal force. Therefore, when the rolling element 103 is returned to the rolling element rolling path 114 via the curved path 115 as described above, a centrifugal force is applied to the rolling element scooping portion 117.
[0009]
However, since the rolling element scooping portion 117 has a sharp shape, it may be damaged by the centrifugal force. Such a phenomenon becomes remarkable when the linear motion guide device is driven at a high speed.
If the radius of curvature of the R-shaped curved path 115 is increased, the centrifugal force can be reduced. However, an upper limit also occurs in the magnitude of the radius of curvature of the curved path 115 depending on the size of the end cap 102B.
[0010]
In addition, if the end cap 102B is made large, the radius of curvature of the curved path 115 can be made large, but this causes a problem that the linear motion guide device becomes large.
For this reason, it has been difficult for the conventional linear guide device to sufficiently reduce the centrifugal force.
[0011]
Further, since there is a play space (see FIG. 16) between the rolling element rolling path 114 (load portion) and the rolling element scooping portion 117, the rolling element 103 largely deviates from the original orbit and the rolling element rolling. Interference with the land of the groove 110 is likely to occur, and the rolling element 103 and the land may be damaged.
Therefore, an object of the present invention is to solve the problems of the conventional linear motion guide device as described above, and to provide a highly durable linear motion guide device that is less likely to be damaged even when driven at high speed. I do.
[0012]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has the following configuration. That is, the linear motion guide device according to the first aspect of the present invention includes a guide rail having a rolling element rolling groove extending in an axial direction on an outer surface, and a rolling element rolling groove opposed to the rolling element rolling groove of the guide rail. And a plurality of rollers rotatably mounted in a rolling element rolling path formed between the two rolling element rolling grooves, the slider being mounted on the guide rail so as to be relatively movable in the axial direction. A rolling element, a rolling element return path for sending the rolling element from an end point to a start point of the rolling element rolling path, and a rolling element for guiding the rolling element positioned at an end point of the rolling element rolling path into the rolling element return path. A rolling element return path, the rolling element return path, a first return path extending in the axial direction, a curved second return path communicating the first return path and the rolling element rolling path, Wherein the slider has a rolling element rolling groove and the first return path. In a linear motion guide device including a ring block and an end cap attached to both ends in the axial direction of the bearing block and having the second return path, the second return path has a plurality of different curvature radii and different curvature centers. It has a curved shape as a whole including the arc of the, the end of the second return path that is continuous with the rolling element scooping portion, the diameter of the arc is a linear distance between both ends of the second return path Are also arc-shaped or linear having a large radius of curvature.
[0013]
According to a second aspect of the present invention, there is provided a linear motion guide device having a guide rail having a rolling element rolling groove extending in an axial direction on an outer surface, and a rolling element rolling groove opposed to the rolling element rolling groove of the guide rail. And a plurality of rollers rotatably mounted in a rolling element rolling path formed between the two rolling element rolling grooves, the slider being mounted on the guide rail so as to be relatively movable in the axial direction. A rolling element, a rolling element return path for sending the rolling element from an end point to a start point of the rolling element rolling path, and a rolling element for guiding the rolling element positioned at an end point of the rolling element rolling path into the rolling element return path. A rolling element return path, the rolling element return path, a first return path extending in the axial direction, a curved second return path communicating the first return path and the rolling element rolling path, Wherein the slider has the rolling element rolling groove and the first return path. In the linear motion guide device, which is composed of a bearing block and an end cap attached to both ends in the axial direction of the bearing block and having the second return path, the second return path has a free curved shape, and The end portion of the second return path that is continuous with the rolling element scooping portion has an arc shape having a radius of curvature larger than an arc whose diameter is a linear distance between both ends of the second return path, or has a linear shape. Features.
[0014]
With such a configuration, the centrifugal force generated when the rolling element passes through the end of the second return path is reduced. Therefore, the scooping portion of the rolling element having a sharp shape is hardly damaged by the centrifugal force, and the linear motion guide device has excellent durability.
In addition, since the play space between the rolling element rolling path (loading portion) and the rolling element scooping portion can be reduced, the rolling element largely deviates from the original track and interferes with the land portion of the rolling element rolling groove. Can be prevented. Therefore, it is possible to prevent the rolling elements and the land from being damaged.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of a linear motion guide device according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view showing an embodiment of a linear motion guide device according to the present invention. 2 is a front view of the linear motion guide device of FIG. 1 viewed from the axial direction (however, the end cap is omitted). FIG. 3 is a cross-sectional view taken along line AA of FIG. FIG. FIG. 4 is a perspective view of the end cap.
[0016]
First, the configuration of the linear motion guide device of the present embodiment will be described. On a guide rail 1 extending in the axial direction and having a substantially rectangular cross section, a metal slider 2 having a substantially U-shaped cross section is assembled so as to be movable in the axial direction.
Rolling element rolling grooves 10, formed of concave grooves having a substantially arc-shaped cross section extending in the axial direction, are formed at ridges where the upper surface of the guide rail 1 intersects the side surfaces 1 a, 1 a. Rolling member rolling grooves 10, which are formed in concave portions having a substantially semicircular cross section and extending in the axial direction, are formed at intermediate positions between both side surfaces 1 a, 1 a of the guide rail 1.
[0017]
The slider 2 is composed of a bearing block 2A forming the main body of the slider 2, and resin-made end caps 2B, 2B detachably attached to both ends in the axial direction. Side seals 5 and 5 for sealing the opening of the gap between the guide rail 1 and the slider 2 are attached to both end portions (end surfaces of the end caps 2B).
[0018]
Further, rolling element rolling grooves 11, 11 having a substantially semicircular cross section facing the rolling element rolling grooves 10, 10 of the guide rail 1 are provided at the corners on the inner side surfaces of both sleeves 6, 6 of the bearing block 2 </ b> A. At the center of the inner side surface of both sleeves 6, 6, rolling element rolling grooves 11, 11 having a substantially semicircular cross section facing the rolling element rolling grooves 10, 10 of the guide rail 1 are formed. I have.
[0019]
The rolling element rolling grooves 10, 10, 10, 10 of the guide rail 1 and the rolling element rolling grooves 11, 11, 11, 11 of both sleeve portions 6, 6 form rolling element rolling paths having a substantially circular cross section. 14, 14, 14, 14 are formed, and these rolling element rolling paths 14 extend in the axial direction. The number of rolling element rolling grooves 10 and 11 provided in the guide rail 1 and the slider 2 is not limited to two rows on one side, and may be, for example, one row on one side or three or more rows on one side.
[0020]
Further, the slider 2 has straight lines formed in the upper and lower portions of the thick portions of the sleeve portions 6 and 6 of the bearing block 2A in parallel with the rolling element rolling paths 14 and having circular cross-sectional through holes penetrating in the axial direction. It has a path 13,13,13,13.
On the other hand, as shown in FIGS. 3 and 4, the end caps 2B, 2B having a substantially U-shaped cross section are provided on the contact surface (rear surface) with the bearing block 2A on the rolling element rolling path 14 and a straight line parallel thereto. A semi-doughnut-shaped curved path 15 that communicates with the path 13 is provided. The linear path 13 and the curved paths 15 at both ends form a rolling element 3 to be described later at an end point of the rolling element rolling path 14. The rolling element return path 16 which is sent from the to the starting point.
[0021]
A substantially annular rolling element circulation path is formed by the rolling element rolling path 14 and the rolling element return path 16, and a number of rolling elements 3 made of, for example, steel balls are loaded in the rolling element circulation path. ing. In addition, the straight path 13 corresponds to a first return path which is a constituent element of the present invention, and the curved path 15 corresponds to a second return path which is a constituent element of the present invention.
When the slider 2 mounted on the guide rail 1 is moved in the axial direction along the guide rail 1, the rolling elements 3 loaded in the rolling element rolling paths 14 roll in the rolling element rolling paths 14. It moves in the same direction as the slider 2 with respect to the guide rail 1 while moving. When the rolling element 3 reaches the end point of the rolling element rolling path 14, the rolling element 3 is guided by a rolling element scooping portion 17 provided continuously at the end of the rolling element return path 16 (curved path 15). It is sent from the moving path 14 to the curved path 15.
[0022]
The rolling element 3 that has entered the curved path 15 makes a U-turn by the curved path 15 and is introduced into the straight path 13, and reaches the opposite curved path 15 through the straight path 13. Here, a U-turn is performed again to return to the rolling element rolling path 14, and such circulation in the rolling element circulation path is repeated indefinitely.
Here, the shape of the curved path 15 will be described in detail with reference to FIG.
[0023]
The curved path 15 of the linear motion guide device of the present embodiment has a curved shape as a whole, but has a single R shape as shown by a broken line (the straight line distance between both ends of the curved path 15 is a diameter. It does not have an arc shape, but has a curved shape in which three arc portions R1, R2, and R3 having different curvature radii and centers of curvature are continuous.
Among the three arc-shaped portions R1, R2, and R3, the arc-shaped portion R1, which is located at the end of the rolling element return path 16 (curved path 15) and is continuous with the rolling element scooping portion 17, is a curved path. 15 has an arc shape having a larger radius of curvature than an arc having a diameter equal to the linear distance between both ends.
[0024]
With such a configuration, the centrifugal force generated when the rolling element 3 passes through the curved path 15 is smaller than when the curved path has a single R shape. Therefore, although the rolling element scooping portion 17 has a sharp shape, damage due to the centrifugal force hardly occurs, so that the linear motion guide device has excellent durability.
Also, as can be seen from FIG. 5, as compared with the case where the curved path 15 is formed into a single R shape having the same radius of curvature as the radius of curvature of the arc-shaped portion R1 (shown by a dashed line in FIG. 5). The size (the length in the axial direction and the length in the direction perpendicular to the axial direction) of the end cap 2B can be significantly reduced. In FIG. 5, the axial length of the end cap 2B that can be suppressed is indicated by Xa, and the length in the direction perpendicular to the axial direction is indicated by Xb.
[0025]
Further, as shown in FIG. 6, the play space between the rolling element rolling path 14 (loading portion) and the rolling element scooping portion 17 is defined by a case where the curved path 15 has a single R shape as shown by a broken line. Can be reduced by the amount of S, so that it is possible to prevent the rolling elements 3 from largely deviating from the original trajectory and interfering with the lands (not shown) of the rolling element rolling grooves 10. Therefore, it is possible to prevent the rolling element 3 and the land from being damaged.
[0026]
Note that the present embodiment is an example of the present invention, and the present invention is not limited to the present embodiment.
For example, the arc-shaped portion R1 that is located at the end of the curved path 15 in FIG. 5 and that is continuous with the rolling element scooping portion 17 may be replaced with a linear portion L as shown in FIG. And two arc-shaped portions having different centers of curvature). Then, the centrifugal force generated when the rolling element 3 passes through the linear portion L is extremely small, so that the rolling element scooping portion 17 is hardly damaged.
[0027]
Further, the curved path 15 may have a curved shape in which four or more arc-shaped portions having different radii of curvature and centers of curvature are continuous. An example of four (R1 to R4) arc-shaped portions is shown in FIG. 8, and an example of five (R1 to R5) is shown in FIG.
Further, if the curved path 15 has a curved shape as a whole, a linear portion L may be interposed between the arc portions as shown in FIGS. 10 and 11.
[0028]
Furthermore, the curved path 15 has a curved shape as a whole, and the portion continuous with the rolling element scooping portion 17 at the end of the curved path 15 has the diameter as the linear distance between both ends of the curved path 15. As shown in FIG. 12, the curved path 15 may have a free curved shape as long as the curved path 15 has an arc shape having a larger radius of curvature than the arc or is linear.
[0029]
【The invention's effect】
As described above, the linear motion guide device of the present invention is hardly damaged even when driven at high speed, and has excellent durability.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of a linear motion guide device of the present invention.
FIG. 2 is a front view of the linear motion guide device of FIG. 1 as viewed from an axial direction.
FIG. 3 is a sectional view taken along line AA of FIG. 2;
FIG. 4 is a perspective view of an end cap.
FIG. 5 is a cross-sectional view illustrating a shape of a curved path.
FIG. 6 is a cross-sectional view illustrating a difference in the size of a play space.
FIG. 7 is a sectional view illustrating the shape of a curved path in another embodiment of the linear motion guide device of the present invention.
FIG. 8 is a sectional view illustrating the shape of a curved path in another embodiment of the linear motion guide device of the present invention.
FIG. 9 is a cross-sectional view illustrating a shape of a curved path in another embodiment of the linear motion guide device of the present invention.
FIG. 10 is a cross-sectional view illustrating a shape of a curved path in another embodiment of the linear motion guide device of the present invention.
FIG. 11 is a sectional view illustrating the shape of a curved path in another embodiment of the linear motion guide device of the present invention.
FIG. 12 is a cross-sectional view illustrating the shape of a curved path in another embodiment of the linear motion guide device of the present invention.
FIG. 13 is a perspective view showing a conventional linear guide device.
14 is a front view of the linear motion guide device of FIG. 13 as viewed from an axial direction.
FIG. 15 is a sectional view taken along line AA of FIG. 14;
FIG. 16 is an enlarged sectional view of a portion near a rolling element scooping portion in a conventional linear motion guide device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Guide rail 2 Slider 2A Bearing block 2B End cap 3 Rolling element 10, 11 Rolling element rolling groove 13 Linear path 14 Rolling element rolling path 15 Curved path 16 Rolling element return path 17 Rolling element pick-up part L Linear part R1 , R2, R3 Arc-shaped part

Claims (2)

A guide rail having a rolling element rolling groove extending in the axial direction on the outer surface, and a rolling element rolling groove facing the rolling element rolling groove of the guide rail, and being attached to the guide rail so as to be relatively movable in the axial direction. Slider, a plurality of rolling elements rotatably mounted in rolling element rolling paths formed between the two rolling element rolling grooves, and the rolling elements from the end point of the rolling element rolling paths. A rolling element return path to be sent to a starting point, and a rolling element scooping section that guides the rolling element located at an end point of the rolling element rolling path into the rolling element return path,
The rolling element return path is configured by a first return path extending in the axial direction, and a curved second return path communicating the first return path and the rolling element rolling path.
A linear guide in which the slider comprises: a bearing block having the rolling element rolling groove and the first return path; and an end cap attached to both ends in the axial direction of the bearing block and having the second return path. In the device,
The second return path has a curved shape as a whole including a plurality of arcs having different radii of curvature and centers of curvature,
The end of the second return path that is continuous with the rolling element scooping portion has an arc shape having a radius of curvature larger than an arc whose diameter is a linear distance between both ends of the second return path, or has a linear shape. A linear motion guide device. A guide rail having a rolling element rolling groove extending in the axial direction on the outer surface, and a rolling element rolling groove facing the rolling element rolling groove of the guide rail, and being attached to the guide rail so as to be relatively movable in the axial direction. Slider, a plurality of rolling elements rotatably mounted in rolling element rolling paths formed between the two rolling element rolling grooves, and the rolling elements from the end point of the rolling element rolling paths. A rolling element return path to be sent to a starting point, and a rolling element scooping section that guides the rolling element located at an end point of the rolling element rolling path into the rolling element return path,
The rolling element return path is configured by a first return path extending in the axial direction, and a curved second return path communicating the first return path and the rolling element rolling path.
A linear guide in which the slider comprises: a bearing block having the rolling element rolling groove and the first return path; and an end cap attached to both ends in the axial direction of the bearing block and having the second return path. In the device,
The second return path has a free-curve shape, and the end of the second return path that is continuous with the rolling element scooping portion is formed by an arc having a diameter equal to a linear distance between both ends of the second return path. A linear motion guide device having an arc shape or a linear shape having a large radius of curvature.

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