JP2012255556A - Linear motion guide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear motion guide of a non-circulation type rolling element, which does not have a risk of detachment of a rolling element retainer from a slider, resulting in inability of accepting load even when a stroke is long relative to a distance in an axial direction between sliders.SOLUTION: The linear motion guide comprises: a guide rail 1; a slider 2 mounted to the guide rail 1 in a manner relatively axially movable; a rolling element row which comprises a plurality of rolling elements 3 aligning along on a rolling element orbit face 10 of the guide rail 1 in an axial direction and in which a part thereof is arranged between rolling element orbit faces 10, 11; a rolling element retainer 4 which retains the rolling element row on the rolling element orbit face 10 of the guide rail 1 in a freely rollable manner and which moves with the relative movement of the slider 2 in a same direction as the slider 2; and a movement error prevention means for making the amount of movement of the rolling element retainer 4 as much as 1/2 of the amount of movement of the slider 2 and preventing error in the amount of the movement of the rolling element retainer 4. Further, the rolling element retainer 4 is configured to be sliding contact with the rolling element orbit face 10 of the guide rail 1.

Description

  The present invention relates to a rolling element non-circulating linear motion guide device.

An example of the configuration of a conventional rolling element circulation type linear motion guide device will be described. The linear motion guide device includes a guide rail having a substantially square cross section extending in the axial direction, and a slider having a substantially U-shaped cross section attached to the guide rail. Two or four rolling element raceway surfaces are formed in the axial direction.
The slider includes a slider body and end caps attached to both end portions in the axial direction. This slider body has a rolling element raceway surface facing the rolling element raceway surface of the guide rail on the inner side surface of both sleeve parts, and has a straight path that penetrates the thick part of the sleeve part in the axial direction. . And the rolling element rolling path is formed by the both rolling element raceway surfaces which oppose.

The end cap has a curved path that allows the rolling element rolling path to communicate with a straight path parallel to the rolling element rolling path. The straight road and the curved roads at both ends constitute a rolling element return path for sending the rolling elements from the end point of the rolling element rolling path to the starting point. The rolling element circulation path is composed of the rolling element return path and the rolling element rolling path. A road is formed. A large number of rolling elements made of steel balls or the like are loaded in the rolling element circulation path.
The slider attached to the guide rail moves smoothly along the guide rail through the rolling of the rolling element in the rolling element rolling path. During the movement, the rolling element moves in the rolling element circulation path in the slider. Roll infinitely while rolling.

  In the linear motion guide device in which the rolling element moves and circulates inside the slider, that is, in the linear motion guide device of the rolling element circulation type, the rolling element enters or exits the load zone. In such a case, minute fluctuations (hereinafter, also referred to as rolling element passing vibration) occur due to imbalance of the load acting on the rolling elements. Although this minute variation is a very minute variation, there is a case where it becomes a problem in a linear motion guide device for a die processing machine and the like that requires high accuracy.

  On the other hand, there is a linear motion guide device that does not include the rolling element return path as described above and does not circulate as described above (hereinafter referred to as a rolling element non-circulating linear motion guide device). . For example, an EPF series linear motion guide device manufactured by THK Corporation may be mentioned. In the conventional rolling element non-circulating linear motion guide device, since the rolling element does not come out of the load zone, it is considered that the rolling element passing vibration basically does not occur. However, in this type of linear motion guide device, the length of the slider in the axial direction needs to be the total length of the range that receives the load from the rolling element and 1/2 of the stroke. There was a problem that it was difficult to realize long strokes.

  Therefore, the rolling element non-circulating linear motion guide device disclosed in Patent Document 1 has a structure that can receive the load from the rolling element over the entire length of the slider in the axial direction. As with the guide device, it is easy to increase the stroke. Further, the rolling element passing vibration is not generated by aligning the axial positions of the respective rolling elements of the plurality of rolling element rows by using the rolling element holder.

JP 2008-115921 A

In general, when a linear motion table such as an XY table is configured using a linear motion guide device, a linear motion guide device having a plurality of sliders may be employed depending on the size and mass of the table. For example, a linear motion table may be configured using two guide rails including two sliders.
Considering the rolling element passing vibration, it is advantageous to make the number of sliders one and increase the axial length. However, if the slider is long, it becomes difficult to process or the shape accuracy of the rolling element raceway surface of the slider (for example, It is difficult to make the accuracy (straightness) highly accurate over the entire length of the slider, so this is not always a good solution if the table is large.

  In such a rolling element non-circulating linear motion guide device having a plurality of sliders, there may be a problem when the stroke is long with respect to the span (axial distance) between the sliders. For example, in a linear motion guide device having two sliders, when a rolling element cage is used for each slider, the axial ends of both rolling element cages are positioned between the two sliders. However, when the amount of movement of the slider increases, one slider reaches the axial ends of the two rolling element cages facing each other. And if the axial direction edge part of a rolling element holder enters into a load zone, since a rolling element does not exist after an axial direction edge part, it becomes impossible to receive a load. When the slider further moves, the rolling element holder comes off from the slider, and there is no longer any rolling element that receives the load, and the rolling element holder can move to a position far away from the slider.

In order to prevent such a problem from occurring, it is necessary to set the length of each rolling element cage so as to cover the stroke range of each slider. Even if the length of the moving body holder is extended, the axial distance between the two sliders needs to be large.
Accordingly, the present invention solves the above-described problems of the prior art, and in a rolling element non-circulating linear motion guide device having a plurality of sliders, the stroke is long with respect to the axial distance between the sliders. Even so, an object of the present invention is to provide a linear motion guide device in which the rolling element cage is not likely to be detached from the slider and receive a load.

In order to solve the above-described problems, an aspect of the present invention has the following configuration. That is, the linear motion guide device according to one aspect of the present invention includes a guide rail having a rolling element raceway surface extending in the axial direction on the outer surface, a rolling element raceway surface facing the rolling element raceway surface of the guide rail, and a shaft. A slider attached to the guide rail so as to be relatively movable in the direction, and a plurality of rolling elements arranged along the axial direction on the rolling element raceway surface of the guide rail, a part of which is the both rolling element raceway surfaces A rolling element row arranged between the rolling element and a rolling element that holds the rolling element row on the rolling element raceway surface of the guide rail so as to freely roll and moves in the same direction as the slider in accordance with relative movement of the slider. And a movement error prevention means for reducing the amount of movement of the rolling element holder so that the movement amount of the rolling element holder is half the amount of movement of the slider. In the motion guide device, Kiten body cage is characterized in that in contact with the guide rail.
With such a configuration, the rolling element holder moves while being guided by the guide rail. Therefore, even if the rolling element holder receives the force generated by the movement error prevention means, the force is applied to the guide rail. Can be received by sliding.

A linear motion guide device according to another aspect of the present invention has a guide rail having a rolling element raceway surface extending in the axial direction on the outer surface, and a rolling element raceway surface facing the rolling element raceway surface of the guide rail. The slider is attached to the guide rail so as to be relatively movable in the axial direction, and a plurality of rolling elements are arranged along the axial direction on the rolling element raceway surface of the guide rail, and a part of the rolling element raceways. A rolling element row arranged between the surfaces, and a rolling element row that holds the rolling element row freely on the rolling element raceway surface of the guide rail and moves in the same direction as the slider with relative movement of the slider. A moving body holder; and a movement error preventing means for preventing an error from occurring in the moving amount of the rolling element holder, wherein the moving amount of the rolling element holder is ½ of the moving amount of the slider. In the linear motion guide device, Rolling body cage is characterized in that the rolling elements are those prepared by insert molding with an insert.
Such a rolling element holder has a structure that encloses and holds the rolling element, and moves while being guided by the rolling element.

  In the linear motion guide device of the present invention, even when the stroke is long with respect to the axial distance between the sliders, there is no possibility that the rolling element retainer is detached from the slider and cannot receive a load.

1 is a side view showing a first embodiment of a linear guide device according to the present invention. It is the front view which looked at the linear motion guide apparatus of FIG. 1 from the axial direction. It is a side view of the small holder | retainer which comprises a rolling element holder | retainer. It is a top view of a small holder. It is a bottom view of a small cage. It is a front view of a small holder. It is XX sectional drawing of FIG. It is a side view of a lid member. It is a figure explaining a complicated type metallic mold. It is a figure explaining a metal mold | die provided with the division | segmentation placing sesame.

An embodiment of a linear motion guide device according to the present invention will be described in detail with reference to the drawings.
[First embodiment]
FIG. 1 is a side view showing a first embodiment of a linear motion guide device according to the present invention. FIG. 2 is a front view of the linear motion guide device of FIG. 1 viewed from the axial direction.
A slider 2 is assembled on a guide rail 1 having a substantially square cross section extending in the axial direction so as to be relatively movable in the axial direction. The cross-sectional shape of the slider 2 is substantially U-shaped, and the cross-sectional shape of the inner surface thereof is a shape along the cross-sectional shape of the outer surface of the guide rail 1. Two rolling element raceway surfaces 10, 10 extending in the axial direction are formed on both side surfaces 1a, 1a of the guide rail 1, respectively.

Further, two rolling element raceway surfaces 11, 11 facing the rolling element raceway surfaces 10, 10 of the guide rail 1 are formed on the inner side surfaces of both sleeve portions 6, 6 of the slider 2. Four rolling element rolling paths are formed by the rolling element raceway surfaces 10, 10, 10, 10 of the guide rail 1 and the rolling element raceway surfaces 11, 11, 11, 11 of both sleeve portions 6, 6. These rolling element rolling paths extend in the axial direction. The number of rolling element raceway surfaces 10 and 11 provided in the guide rail 1 and the slider 2 is not limited to two on one side, and may be one or more on one side, for example.
Further, a plurality of rolling elements 3 arranged along the axial direction are arranged on each rolling element raceway surface 10 of the guide rail 1 so as to be freely rotatable, and a rolling element row is formed by these rolling elements 3. ing. In FIGS. 1 and 2, the rolling elements 3 are balls, but rollers may be used.

  Furthermore, between the inner surface of the slider 2 and the outer surface of the guide rail 1, a rolling element holder 4 is disposed on the rolling element raceway surface 10 of the guide rail 1 to hold the rolling element 3 in a freely rolling manner. The cross-sectional shape of the rolling element cage 4 is substantially U-shaped along the cross-sectional shape of the inner surface of the slider 2 and the cross-sectional shape of the outer surface of the guide rail 1, and both sides thereof (the side surface 1a of the guide rail 1 and the slider). 2), a plurality of pockets for accommodating the rolling elements 3 and holding them in a freely rollable manner are formed side by side at regular intervals along the axial direction. And a pocket is formed so that the axial direction position of the rolling element 3 arranged on the rolling element raceway surface 10 is aligned with the axial position of the rolling element 3 arranged on the rolling element raceway surface 10 of the other strip. ing. Therefore, the timing at which the rolling elements 3 exit and enter the rolling element rolling path as the slider 2 moves is aligned on the rolling element raceway surface 10 of each row.

Since the axial length of the rolling element cage 4 is sufficiently longer than the axial length of the slider 2, a part of the rolling element row is between the rolling element raceway surfaces 10, 11 (that is, the rolling element rolling path). However, the remaining part of the rolling element row is not arranged between the rolling element raceway surfaces 10 and 11, and is exposed as shown in FIG.
In such a linear motion guide device, the slider 2 assembled to the guide rail 1 smoothly moves in the axial direction along the guide rail 1 through the rolling of the rolling element 3 in the rolling element rolling path. Can move. At this time, the rolling element holder 4 moves in the same direction as the slider 2 as the slider 2 moves. Even if the slider 2 moves, the rolling element 3 held by the rolling element holder 4 is present at the moved position, so that the movement can be continued through the rolling of the rolling element 3. Therefore, in the linear motion guide device according to the present embodiment, rolling element passing vibration is suppressed and a long stroke of the slider 2 is ensured.

  Such a linear motion guide device is provided with a movement error preventing means for preventing an error from occurring in the moving amount of the rolling element holder 4. The movement error preventing means in the linear motion guide device of FIGS. 1 and 2 is constituted by a rack and pinion 5. That is, the first rack 21 attached to the rolling element holder 4 along the axial direction, the second rack 22 attached to the guide rail 1 along the axial direction, and the slider 2 are rotatable. The rack and pinion 5 includes a pinion 23 that is attached and meshes with the racks 21 and 22. The axial length of the first rack 21 may be the same as the axial length of the rolling element holder 4, and the axial length of the second rack 22 may be the same as the axial length of the guide rail 1. In FIG. 2, a second rack 22 is attached to the side surface 1 a of the guide rail 1, and a pinion 23 is attached to the outer surface of the sleeve 6 of the slider 2.

The pinion 23 is a two-stage gear in which a first gear 23 a that meshes with the first rack 21 and a second gear 23 b that meshes with the second rack 22 are fixed to a concentric shaft. The pitch circle diameter (PCD) of the second gear 23b is twice the pitch circle diameter (PCD) of the first gear 23a.
With such a configuration, the pinion 23 can always mesh with the first rack 21 and the second rack 22, so when the slider 2 and the rolling element holder 4 move, There is no possibility that the pinion 23 comes off from the second rack 22 and does not mesh. Therefore, the number of pinions 23 to be provided is sufficient, so that the number of parts can be reduced and the time and effort for assembling the linear motion guide device can be reduced. Can be reduced.

  The rolling element holder 4 and the first rack 21 may be separate members, and the first rack 21 may be attached to the rolling element holder 4, but the teeth that mesh with the pinion 23 in a part of the rolling element holder 4. The first rack 21 may be formed by molding or processing. If the rolling element holder 4 and the first rack 21 are separate members, for example, the first rack 21 having a longer axial length than the rolling element holder 4 is used to connect the first rack 21 to the seam. The structure can be made with little or no. If there is a seam in the first rack 21, there is a step there, and there is a possibility that the pinion 23 may be caught when passing through the step, but if there are few or no seams, such trouble is suppressed. .

  On the other hand, if the first rack 21 is formed in the rolling element holder 4, the number of parts can be reduced, which contributes to cost reduction. However, in this case, it is preferable not to cause a step at the joint of the first rack 21. As a method for preventing the step, for example, a convex portion is provided on one end surface of the first rack 21, a concave portion that fits the convex portion is provided on the other end surface, and the convex portion and the concave portion are fitted to each other. A method of connecting the first racks 21 is mentioned. Alternatively, hooks may be provided on both end faces of the first rack 21 and the first rack 21 may be coupled by hooking the hooks together. Further, a separate back plate may be provided on the lower side or back side of the first rack 21.

  Here, the structure of the rolling element holder 4 will be described. The rolling element holder 4 may be composed of an integrally formed member. However, in the linear motion guide device of the present embodiment, as shown in FIG. 1, a small holder 4A having a short axial length is provided. A plurality of rolling element holders 4 are connected in the axial direction. With such a configuration, the small cage 4A is mass-produced at a low cost by resin injection molding, and the small cage 4A is connected according to the use condition and stroke of the linear motion guide device, and the desired axial length The rolling element holder 4 can be configured.

  FIG. 3 is a side view of the small cage 4A constituting the rolling element cage 4, FIG. 4 is a top view thereof, FIG. 5 is a bottom view thereof, FIG. 6 is a front view thereof, and FIG. Show. The small cage 4A is composed of a plurality of plate-like members arranged at equal intervals along the axial direction and parallel to each other, and a top plate 43 and a side plate 44 that connect and fix these plate-like members. It is a rectangular parallelepiped member. As this plate-like member, the rolling plates 3 in each row are separated from the end plates 42, 42 arranged at both ends in the axial direction of the small cage 4 </ b> A and the rolling members 3 arranged between the both plates 42, 42. And a plurality of intermediate plates 41 that align the axial positions of the two. The top plate 43 is disposed on the upper part of the plate member, and the side plates 44 are disposed on both sides of the plate member. The top plate 43 and the side plate 44 both extend in the axial direction and connect all the plate members. Yes. A rack mounting portion 45 is provided so as to connect the both end plates 42, 42 of each small cage 4A. Further, the small holder 4A is provided with a connecting portion 46 for connecting the small holders 4A to each other.

  The end plate 42 is formed with a through hole 42 a for attaching a rod-like lid member 47 (see FIG. 8) that supports the rolling element 3 from below and prevents the rolling element 3 from falling. The lid member 47 is attached along the axial direction between the end plates 42 and 42 at both ends by fitting the provided protrusions into the through holes 42a. The gap formed between the top plate 43 and the side plate 44 and the gap formed between the side plate 44 and the lid member 47 are both smaller than the diameter of the rolling element 3. Thereby, even when the rolling element 3 is not restrained between the guide rail 1 and the slider 2, the rolling element 3 held by the rolling element holder 4 is not likely to drop off.

  As can be seen from FIG. 6, the cross-sectional shape of the end plate 42 is substantially U-shaped along the cross-sectional shape of the inner surface of the slider 2 and the cross-sectional shape of the outer surface of the guide rail 1. A portion of the end plate 42 facing the rolling element raceway surface 10 of the guide rail 1 is in sliding contact with the rolling element raceway surface 10. When the sliding contact portion 42b of the end plate 42 and the rolling element raceway surface 10 of the guide rail 1 are in sliding contact with each other, the rolling element holder 4 is guided by the guide rail 1 and moves. Thereby, even if the rolling element holder 4 receives a force generated by the engagement of the first rack 21 and the pinion 23, the force can be received by sliding with the guide rail 1.

  The contact point between the rolling element holder 4 and the guide rail 1 is not limited to the rolling element raceway surface 10, and for example, contacts with a portion other than the rolling element raceway surface 10 on the upper surface or the side surface 1 a of the guide rail 1. Or you may contact the upper surface of the guide rail 1 including the rolling-element track surface 10, and the whole side surface 1a. And you may give the role of a seal | sticker or a scraper to the sliding contact part 42b of the rolling element holder | retainer 4. FIG. If it does so, the foreign material adhering to the guide rail 1 can be removed easily. Further, a labyrinth seal may be configured by providing a slight gap between the rolling element holder 4 and the guide rail 1.

  In the present embodiment, the end plate 42 and the intermediate plate 41 have different shapes, and only the end plate 42 is provided with a sliding contact portion 42b that is in sliding contact with the rolling element raceway surface 10. This is intended to mass-produce the small cage 4A at low cost by resin injection molding. As the mold used in the injection molding, for example, a mold composed of four molds that open in the four directions of the small cage 4A in both the vertical direction and the axial direction is preferable. If such a mold is used, the resin is injected into several cavities, and then the mold is slid to connect the cavities to make a product. The cage 4A can be manufactured.

  Since the structure of the complex type mold is very complicated and expensive, the use of such a complex type mold increases the manufacturing cost of the small cage 4A. You can use complex molds. Then, the intermediate plate 41 can also be provided with a sliding contact portion that comes into sliding contact with the rolling element raceway surface 10. Further, the intermediate plate 41 may be provided with a slidable contact portion that slidably contacts only the upper two rows of the four rows of rolling element raceway surfaces 10 (this is possible without using the above complex type mold). Is).

[Second Embodiment]
Since the configuration and operation of the linear motion guide device of the second embodiment are substantially the same as those of the first embodiment, only different parts will be described, and description of the same parts will be omitted.
In the first embodiment, the rolling element holder and the guide rail are in sliding contact with each other, so that the rolling element holder is guided and moved by the guide rail. However, in the second embodiment, the rolling element holder is moved. The moving body holder and the guide rail are not in contact with each other, and the rolling body holder is guided and moved by the rolling body. For this purpose, the rolling element holder needs to have a structure that encloses and holds the rolling element.

  Since the rolling element cage having such a structure has a very complicated shape, it is difficult to manufacture the rolling element cage by an inexpensive manufacturing method such as a general injection molding method. It can be manufactured by the injection molding method used. Moreover, the rolling element holder of the said structure can also be manufactured by dividing and manufacturing separately the part which wraps and hold | maintains a rolling element, and parts other than the part, and assembles it later. Furthermore, using a mold having the above-mentioned complex type mold or divided placing sesame (which is a part of the mold, but comes out of the mold body together with the product during injection molding), The rolling element cage having the above structure can also be manufactured by insert molding using the rolling element as an insert.

An example of the above complex type mold is shown in FIG. In addition, the term which shows directions, such as up and down, right and left in the following description, will mean each direction in each figure for convenience of explanation, unless there is particular notice.
In this example, a mold is constituted by three molds 51, 52 and 53. A rolling element is interposed between the mold 51 and the mold 52 and between the mold 51 and the mold 53, and after the resin is injected, the mold 51 is pulled rightward, and the mold 52 is moved upward to move the mold. The rolling element holder can be manufactured by connecting the two members constituting the rolling element holder together with 53.

Moreover, the example of a metal mold | die provided with the division | segmentation sesame is shown in FIG. In this example, a mold is composed of two molds 54 and 55 and three placing sesame 56, 57 and 58. A rolling element is interposed between the die 54 and the placing sesame 56 and between the die 55 and the placing sesame 58, and after the resin is injected, the die 54 is pulled out to the left and the die 55 is pulled out to the right. . Then, the product is taken out with the three sesame seeds 56, 57, and 58 attached. When the placing sesame 57 is pulled downward, the placing sesame 56 and 58 are also detached, so that a product is obtained.
When slipping with the guide rail becomes a problem when the rolling element cage is guided and moved by the rolling element, for example, a roller follower that rolls on the side surface of the guide rail is attached to the rolling element cage. May be.

DESCRIPTION OF SYMBOLS 1 Guide rail 2 Slider 3 Rolling body 4 Rolling body holder 4A Small holder 5 Rack and pinion 10 Rolling body raceway surface 11 Rolling body raceway surface 21 First rack 22 Second rack 23 Pinion 23a First gear 23b First Second gear 42b Sliding part

Claims (2)

A guide rail having an outer raceway raceway surface extending in the axial direction; a slider having a racer raceway surface facing the rolling body raceway surface of the guide rail and attached to the guide rail so as to be relatively movable in the axial direction; A plurality of rolling elements arranged along the axial direction on the rolling element raceway surface of the guide rail, a part of which is arranged between the rolling element raceway surfaces, and the rolling of the guide rail. A rolling element holder that holds the rolling element row on a moving body raceway surface in a freely rolling manner and moves in the same direction as the slider as the slider moves relative to each other, and a movement amount of the rolling element holder in the slider In the linear motion guide device comprising: a movement error preventing means that prevents an error from occurring in the movement amount of the rolling element retainer,
The linear motion guide device, wherein the rolling element cage is in contact with the guide rail. A guide rail having an outer raceway raceway surface extending in the axial direction; a slider having a racer raceway surface facing the rolling body raceway surface of the guide rail and attached to the guide rail so as to be relatively movable in the axial direction; A plurality of rolling elements arranged along the axial direction on the rolling element raceway surface of the guide rail, a part of which is arranged between the rolling element raceway surfaces, and the rolling of the guide rail. A rolling element holder that holds the rolling element row on a moving body raceway surface in a freely rolling manner and moves in the same direction as the slider as the slider moves relative to each other, and a movement amount of the rolling element holder in the slider In the linear motion guide device comprising: a movement error preventing means that prevents an error from occurring in the movement amount of the rolling element retainer,
The linear motion guide device, wherein the rolling element retainer is manufactured by insert molding using the rolling element as an insert.

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