WO2010074155A1

WO2010074155A1 - Rolling element retainer and endless circulation type linear motion device using same

Info

Publication number: WO2010074155A1
Application number: PCT/JP2009/071457
Authority: WO
Inventors: 白井　武樹; 飯田　勝也; 堀江　拓也
Original assignee: Thk株式会社
Priority date: 2008-12-26
Filing date: 2009-12-24
Publication date: 2010-07-01
Also published as: TW201030251A; JPWO2010074155A1

Abstract

Provided are a rolling element retainer having high durability achieved by minimizing as much as possible bending stress acting on the outer surfaces of connecting sections, and an endless circulation type linear motion device using the rolling element retainer. A rolling element retainer is provided with: ball retaining sections (10) which serially retain balls (2) arranged at predetermined intervals and are adapted to hold each of the balls (2) so as to sandwich the ball from the front and rear in the direction in which the balls are arranged; wing sections (22) projecting from each of the ball retaining section (10) in the direction normal to the direction in which the balls are arranged; and flexible connecting sections (23) for connecting between the wing sections (22). The rolling element retainer is configured so that, with the balls retained by the ball retaining sections (10), the direction of the arrangement of the balls (2) can be bent by deformation of the connecting sections (23). The width (A1) of each of the wing section (22) in the direction in which the balls are arranged is set to be equal to or less than the width (A0) of each of the ball retaining sections (10) in the direction in which the balls are arranged.

Description

Rolling body retainer and infinite circulation type linear motion apparatus using the same

The present invention relates to a rolling element retainer used for various rolling guide devices such as a linear motion guide device, a ball spline, and a ball screw, and an infinite circulation linear motion device using the same.

As a conventional rolling element retainer of this type, the present applicant has already proposed a rolling element retainer as described in Patent Document 1.
That is, a plurality of rolling elements arranged at a predetermined interval are held in series, and a rolling element holding part that holds the rolling elements so as to be sandwiched from the front and rear along the arrangement direction of the rolling elements, and a rolling element holding part. And a linear member is integrally embedded in the connecting portion.
By burying the linear member in this way, the tensile strength is increased and the durability can be improved.

Republished WO2003 / 803068

The present invention has been made to further improve the rolling element retainer as described above, and its purpose is to reduce the bending stress acting on the outer surface of the connecting portion as much as possible, and to improve durability. It is an object of the present invention to provide a rolling element retainer and an infinite circulation type linear motion device that can further improve the speed.

In order to achieve the above object, the present invention holds a plurality of rolling elements arranged at a predetermined interval in series, and holds the rolling elements so as to be sandwiched from the front and rear along the arrangement direction of the rolling elements. A holding part, a wing part protruding in a direction orthogonal to the rolling element arrangement direction from the rolling element holding part, and a flexible connecting part that connects the wing parts, and deformation of the connecting part Thus, in the rolling element retainer capable of bending the rolling element arrangement direction while being held by the rolling element holding part, the width of the wing part in the rolling element arrangement direction is set to the rolling element arrangement of the rolling element holding part. It is characterized by being less than the width of the direction.
The thickness of the connecting portion in the direction orthogonal to the rolling element arrangement direction is preferably smaller than the thickness of the wing part in the direction orthogonal to the rolling element arrangement direction.
The cross-sectional shape of the connecting portion is preferably a circular shape. The circular shape includes not only a perfect circle but also an elliptical shape. Moreover, it is preferable that a connection part is a resin material and is an extending | stretching material, Furthermore, it is suitable for a connection part to be integrally shape | molded with the rolling element holding | maintenance part and the wing part.
In the present invention, not only the rolling element holding parts are arranged every other rolling element, but also the rolling element holding parts are arranged every two rolling elements, and the rolling element holding parts are separated from each other by two rolling elements. It may be configured to sandwich.
In the infinite circulation type linear motion device of the present invention, the rolling element retainer is incorporated in the rolling element circulation path.

According to the present invention, by providing a flexible connecting portion between the wing portions, it is easy to bend and deform at the time of changing the direction, and the width of the wing portion in the rolling element arrangement direction is equal to or less than the width of the rolling element holding portion. By doing so, the exposed connecting portion becomes long and easily bent, the bending stress acting on the connecting portion can be reduced as much as possible, and the fatigue strength can be increased.

1A and 1B show a rolling element retainer according to a first embodiment of the present invention, in which FIG. 1A is a partial perspective view with a ball removed, FIG. 1B is a partial perspective view with a ball assembled, (C) is a plan view of a partly broken main part, (D) is a front view of a partly broken main part, (E) is a left side view, and (F) shows the relationship between the ball holding part and the wing part. It is a schematic diagram. FIG. 2A is a partial perspective view showing a part of an example of the linear motion guide device in which the rolling element retainer of FIG. 1 is incorporated, FIG. 2B is an enlarged perspective view of the ball circulation path, and FIG. Is a partial cross-sectional view of the direction change path, and (D) is a partial perspective view of the rolling element retainer when the direction is changed. 3A and 3B show a rolling element retainer according to a second embodiment of the present invention, in which FIG. 3A is a partial perspective view with a roller removed, FIG. 3B is a partial perspective view with a roller assembled, and FIG. (D) is a partially broken enlarged front view, (E) is a left side view, and (F) is a schematic diagram showing the relationship between the ball holding part and the wing part. 4A and 4B show a modification of the rolling element retainer according to the first embodiment of the present invention. FIG. 4A is a plan view of a partly broken main part, FIG. 4B is a front view of a partly broken main part, and FIG. ) Is a partial cross-sectional view when the direction is changed.

BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described below in detail based on the illustrated embodiment.
Example 1
FIG. 1 shows a rolling element retainer according to a first embodiment of the present invention.
The rolling element retainer 1 is a ball retainer that holds a ball 2. In other words, a plurality of balls 2 arranged at predetermined intervals are held in series, and a ball holding unit 10 that holds each ball 2 so as to be sandwiched from the front and rear along the ball arrangement direction, and the ball holding unit 10 to the ball A wing portion 22 protruding in a direction orthogonal to the arrangement direction, and a flexible connecting portion 23 that connects the wing portions 22, and is held by the ball holding portion 10 by deformation of the connecting portion 23 Thus, the arrangement direction of the balls 2 can be bent.

The balls 2 are rotatably held so that the rotation axes of the balls 2 are parallel to each other while being sandwiched between the ball holding portions 10.
Here, in the following description, as shown in FIG. 1, assuming the orthogonal coordinates of the X axis, the Y axis, and the Z axis orthogonal to each other, the arrangement direction of the balls is the X axis direction, and the rotation axis direction of the balls 2 is Y The direction orthogonal to the axial direction, the X-axis, and the Y-axis will be described as the Z-axis direction.
The ball holding portions 10 are arranged every other ball and sandwich the balls 2 one by one from the front and rear. The structure of the ball holding portion 10 is a flat cylindrical member having a diameter smaller than the ball diameter, and holding recesses 10a for slidably holding the ball 2 are provided on both end faces thereof. The holding recess 10a is formed in a spherical shape into which the ball crown portion of the ball 2 enters. However, the shape of the ball holding portion 10 is not limited to a cylindrical shape.

The width of the wing portion 22 in the X-axis direction (ball arrangement direction) is set to be the same as the width of the ball holding portion 10 in the X-axis direction in the illustrated example, but as schematically shown in FIG. Further, it is preferable that the width A1 of the wing portion 22 in the X-axis direction is set to be equal to or smaller than the width A0 of the ball holding portion 10 in the X-axis direction.
Further, the wing portion 22 has a thin plate shape, and as shown in FIG. 1F, the thickness B1 in the Z-axis direction (the direction perpendicular to the ball arrangement direction and the ball rotation axis direction) is Z-axis of the ball holding portion 10. It is smaller than the thickness B0 in the direction. Further, the thickness t of the connecting portion 23 in the Z-axis direction is smaller than the thickness B1 of the wing portion 22 in the Z-axis direction.
Further, the position of the wing portion 22 in the Z-axis direction is deviated by a predetermined amount with respect to the center of the ball, and the deviated direction is on the inner peripheral side when the direction is changed.

The connecting portion 23 is composed of a linear member 30 that is a resin material and is a stretched material, and is integrally formed with the ball holding portion 10 and the wing portion 22. The linear member 30 extends over the entire length of the rolling element retainer 1 along the arrangement direction X of the balls 2. A portion in the middle of the linear member 30 is integrally fixed in a state of penetrating each wing portion 22, and a portion partially exposed between the wing portions 22 is configured as a connecting portion 23.
The cross-sectional shape of the linear member 30 is preferably a circular shape. The cross-sectional shape is not limited to a perfect circle or ellipse, but includes a shape close to a circle.

The linear member 30 is integrally formed with the ball holding portion 10 and the wing portion 22 by insert molding.
For the ball holding portion 10 and the wing portion 22, resin materials that can be injection-molded, for example, various resin materials such as polyester, nylon, polyolefin, acrylic, and fluororesin can be used. In particular, an oil-free linear motion guide device can be realized by using an oil-containing resin.

On the other hand, the linear member 30 is a resin thread, and is stretched to orient the molecular chain. By extending | stretching, the density between each molecule | numerator becomes high and tensile strength becomes high. There is no particular limitation on the structure of the fiber and the spinning structure.
Although the material of the linear member 30 is not specifically limited, The material which does not swell with respect to the liquid agent of use environments, such as a coolant, for example, a carbon fiber, a fluororesin fiber, etc. is suitable. In this way, it is not necessary to consider the elongation allowance due to the swelling of the rolling element retainer, and when installing in the circulation path, the gap between both ends of the rolling element retainer can be made as small as possible. You can increase the number. Further, a heat-resistant material such as carbon fiber may be selected, and it can be used even in an environment at a high temperature.
By making the linear member 30, the ball holding part 10, and the wing part 22 into separate structures, the selection range of the resin material is expanded, and a durable and non-swelling retainer can be realized.

However, the linear member 30 may be made of the same resin as the ball holding unit 10 and the wing unit 22. If the same resin is used, the adhesiveness between the linear member 30 and the wing part 22 is good and can be firmly fixed.
Moreover, as the linear member 30, glass fiber, a metal wire, etc. other than a resin thread | yarn can also be used. In the illustrated example, one linear member 30 is arranged on each side of the ball row, but a plurality of linear members 30 may be arranged. Moreover, the linear member 30 is not limited to a thread-like form, and includes a belt-like form.
In addition, in the said Example, although the linear member 30 and the wing part 22 are being fixed, it does not need to be fixed and the contact part of the linear member 30 and the wing part 22 may be relatively movable. .

2A is a partially broken partial perspective view showing an example of a linear motion guide device as an infinite circulation linear motion device in which the rolling element retainer of FIG. 1 is incorporated, and FIG. 2B is an enlarged perspective view of a ball circulation path. (C) is a fragmentary sectional view of a direction change path, (D) is a fragmentary perspective view of the rolling element retainer at the time of a direction change.
The linear motion guide device 50 includes a track rail 51 and a moving block 52 that is slidably assembled to the track rail 51 via a large number of balls 2. The ball 2 is held by the rolling element retainer 1 and is incorporated into a ball circulation path 53 that is a rolling element circulation path formed in the moving block 52.

The ball circulation path 53 includes a load ball path 54 that extends linearly, a no-load ball path 55 that extends in parallel with the load ball path 54, and a direction change path that connects both ends of the load ball path 54 and the no-load ball path 55. 56.
When the moving block 52 moves to one side, the ball 2 moves while rolling in the moving direction of the moving block 52 in the load ball path 54, and the ball 2 moves from the no-load ball path 55 to the load ball path 54 through the direction change path 56. Moving. At the same time, it is pushed out to the unloaded ball passage 55 through the opposite direction change passage 56 and circulates and moves through the ball circulation passage 53 while being held at a constant interval by the ball holding portion 10 of the rolling element retainer 1.

Each time the ball 2 passes through the direction change path 56, the connecting portion 23 between the wing portions 22 is repeatedly bent. In the present embodiment, since the width of the wing portion 22 in the X-axis direction is the same as that of the ball holding portion 10, the connecting portion 23 exposed between the wing portions 22 is long and easily bent. Therefore, the bending stress acting on the connecting portion 23 is reduced as much as possible, the fatigue strength is increased, and the durability is improved.
As the width of the wing portion 22 in the X-axis direction is smaller than the width of the ball holding portion 10 in the X-axis direction, as shown in FIG. Bending stress is reduced.
Explaining this point in detail, the bending stress acting on the connecting portion 23 increases as the radius of curvature of the direction change path 56 decreases and the thickness t of the connecting portion 23 increases. Conversely, the larger the radius of curvature of the direction change path 56 is, and the smaller the thickness t of the connecting portion 23 is, the smaller it becomes. Therefore, it is conceivable to enlarge the direction changing path 56, but the size of the direction changing path 56 is restricted because the apparatus is enlarged.
If the radius of curvature of the direction change path 56 is constant, using a rolling element retainer in which the wing part 22 is long and the connection part 23 is not exposed so much, the connection part 23 is shortened. The curvature of the connecting portion 23 increases, leading to an increase in bending stress.
Therefore, in the present invention, the wing part 22 is made smaller than the ball holding part 10 and the connecting part 23 is made as long as possible, and the curvature of the connecting part 23 when reaching the direction change path 56 is made as much as possible. As a result, the bending stress is reduced.
Assuming the curvature radius of the connecting portion 23, if the connecting portion 23 is short, the curvature radius becomes smaller than the curvature radius of the direction change path 23. If the wing portion 22 is made as small as the ball holding portion 10 as in the present invention, the curvature radius of the curved connecting portion 23 can be gradually reduced to a size close to the curvature radius of the direction change path 56.

Further, since the thickness t of the connecting portion 23 in the Z-axis direction is also smaller than the thickness of the wing portion 22 in the Z-axis direction, the bending rigidity itself is small and the bending stress can be further reduced. Furthermore, since the cross-sectional shape of the connecting portion 23 is circular, even if the bending direction of the connecting portion 23 varies due to the inclination of the wing portion 22 or the like during the direction change, the bending stress is uniform. In particular, in the case where the linear member 30 itself constituting the connecting portion 23 is a yarn obtained by spinning a thin fiber, the bending stress is dispersed in each fiber, so that it is very small.
In this embodiment, the length of the connecting portion 23 is a straight line between the wing portions 22 of the ball holding portion 10 in a straight path so that a minute gap is formed between the ball 2 and the holding concave portion 10a of the ball holding portion 10. In some cases, the length of the connecting portion 23 may be longer than the linear distance between the wing portions 22 of the ball holding portion 10 in the straight path, and the slack in the direction change path may be increased. Good.

FIG. 4 shows a modification of the first embodiment.
In this modification, the ball holding portions 10 are arranged in every two balls, and two balls 2 are sandwiched from the front and the back by the ball holding portions 10.
Even when the two balls 2 are sandwiched in this way, when they are on a straight line, as shown in FIG. 4B, the interval W1 between the adjacent ball holding portions 10 is 2 in the contact state. Since it is smaller than the interval W2 between the two balls, the ball 2 does not fall off. When there are three balls 2, the balls fall off, so it is preferable to place every two balls.

By holding the balls 2 two by two, as shown in FIG. 4C, the length of the connecting portion 23 between the ball holding portions 20 is increased, and the amount of slack in the connecting portion 23 in the direction change path 56 is increased accordingly. Is increased, the bending stress can be further reduced.
When assembled in the ball circulation path 53, the position of the ball holding portion 10 is determined by the ball 2 and guided all around, so that the ball holding portion 10 and the linear member 30 are connected to the loaded ball passage 54, the no-load ball passage. 55 and the direction change path 56 move without contacting the passage walls.
In some cases, in one rolling element retainer, the ball holding portion 10 may be configured such that a portion where every two balls are arranged and a portion where every other ball is arranged are mixed.

Example 2
Next, a second embodiment of the present invention will be described.
FIG. 3 shows a rolling element retainer according to Embodiment 2 of the present invention.
This rolling element retainer 100 is a type of roller retainer that holds a roller 102.
That is, a plurality of rollers 102 arranged at a predetermined interval are held in series, a roller holding unit 110 that holds each roller 102 so as to be sandwiched from the front and rear along the roller arrangement direction, and the roller holding unit 110 to the roller. A wing portion 122 protruding in a direction orthogonal to the arrangement direction, and a flexible connecting portion 123 that connects the wing portions 122, and is held by the roller holding portion 110 by deformation of the connecting portion 123 Thus, the arrangement direction of the balls 2 can be bent.

The roller 102 is rotatably held so that the rotation axes of the roller 102 are parallel to each other while being sandwiched between the roller holding portions 110. Also in the second embodiment, as shown in FIG. 3, assuming the orthogonal coordinates of the X axis, the Y axis, and the Z axis that are orthogonal to each other, the arrangement direction of the rollers 102 is the X axis direction, and the rotation axis direction of the rollers 102 is the Y axis. A direction orthogonal to the axial direction, the X-axis, and the Y-axis is taken as a Z-axis direction.

The roller holder 110 is a rectangular parallelepiped block smaller than the roller diameter, and is provided with holding recesses 110a for slidably holding the rollers 102 on both front and rear sides in the arrangement direction. The holding recess 110a is formed in an arcuate surface shape into which the arc portion of the roller 102 enters. However, the shape of the roller holding portion 110 is not limited to a rectangular parallelepiped shape.

The width of the wing portion 122 in the X-axis direction (roller arrangement direction) is set to the same width as the width of the ball holding portion 10 in the X-axis direction in the illustrated example, but as schematically shown in FIG. In addition, the width A1 ′ in the X-axis direction of the wing part 122 is preferably set to be equal to or smaller than the width A0 ′ in the X-axis direction of the ball holding part 10.
On the other hand, the wing part 122 has a thin plate shape, and as shown in FIG. 1 (F), the thickness B1 ′ in the Z-axis direction (the direction perpendicular to the roller arrangement direction and the roller rotation axis direction) is Z of the roller holding part 110. It is smaller than the axial thickness B0 ′. Further, the thickness of the connecting portion 123 in the Z-axis direction is smaller than the thickness of the wing portion 122 in the Z-axis direction.
In the second embodiment, the position of the wing portion 122 in the Z-axis direction substantially coincides with the center of the roller 102. Of course, it may be shifted as in the first embodiment.

The connecting portion 123 is composed of a linear member 130 that is a resin material and is a stretched material, and is integrally formed with the roller holding portion 110 and the wing portion 122. The linear member 130 extends over the entire length of the rolling element retainer 101 along the arrangement direction X of the rollers 102. An intermediate portion of the linear member 130 is integrally fixed in a state of penetrating each wing portion 122, and a portion that is partially exposed between the wing portions 122 is configured as a connecting portion 123.

The roller holding part 110 and the wing part 122 are molded by injection molding, and the linear member 130 is integrally molded by insert molding together with the roller holding part 110 and the wing part 122.
The materials of the roller holding part 110 and the wing part 122 and the linear member 130 are the same as those in the first embodiment.

Also, the configuration of the roller circulation path of the linear motion guide device is the same as that of the ball circulation path shown in FIG. Does not deform.

In particular, in the case of the roller 102, since the roller 102 is held in parallel between the rotation axes of the rollers 102 by the roller holding portions 110 positioned in the front and rear of the moving direction, the occurrence of skew is prevented.
In the rolling element retainer of the second embodiment, as in the modification of the first embodiment shown in FIG. 4, the roller holding portions 210 are arranged every two rollers, and the rollers 102 are moved back and forth by the roller holding portions 210 two by two. It can be set as the structure pinched | interposed from.
Further, the materials, shapes, relative arrangements, and the like of the component parts described in the above embodiments are not intended to limit the scope of the present invention only to those unless otherwise specified.

1 Rolling element retainer (for balls)
2 balls (rolling elements)
DESCRIPTION OF SYMBOLS 10,110 Ball holding part 11 Linear member 22,122 Wing part 23,123 Connection part 30,130 Linear member 53 Ball circulation path 56 Direction change path 101 Rolling body retainer (for rollers)
102 Roller (rolling element)
A0, A0 ′ Ball, roller holding portion X-axis width A1, A1 ′ wing portion X-axis width B0, B0 ′ Ball, roller holding portion Z-axis thickness B1, B1 ′ wing portion Z Axial thickness

Claims

A plurality of rolling elements arranged at a predetermined interval are held in series, and a rolling element holding part that holds the rolling elements so as to be sandwiched from the front and rear along the arrangement direction of the rolling elements, and a rolling element from the rolling element holding part. A wing portion projecting in a direction orthogonal to the moving body arrangement direction, and a flexible connection portion that connects the wing portions, and is held by the rolling element holding portion by deformation of the connection portion. In the rolling element retainer capable of bending the arrangement direction of the rolling elements,
A rolling element retainer, wherein a width of the wing portion in the rolling element arrangement direction is equal to or less than a width of the rolling element holding portion in the rolling element arrangement direction.
2. The rolling element retainer according to claim 1, wherein a thickness of the connecting portion in a direction orthogonal to the rolling element arrangement direction is smaller than a thickness of the wing part in a direction orthogonal to the rolling element arrangement direction.
The rolling element retainer according to claim 1 or 2, wherein a cross-sectional shape of the connecting portion is circular.
The rolling element retainer according to any one of claims 1 to 3, wherein the connecting portion is a resin material and a stretched material.
The rolling element retainer according to any one of claims 1 to 4, wherein the connecting portion is formed integrally with the rolling element holding portion and the wing portion.
The rolling element retainer according to any one of claims 1 to 5, wherein the rolling element holding portions are arranged every other rolling element.
The rolling element retainer according to any one of claims 1 to 5, wherein the rolling element holding portions are arranged every two rolling elements.
An infinite circulation linear motion device in which the rolling element retainer according to any one of claims 1 to 7 is incorporated in a rolling element circulation path.