JPH0620893Y2 - Linear guide device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is provided with a ball circulating passage interposed between a guide rail having a single row of ball rolling grooves and a slider freely traveling on the guide rail. The present invention also relates to a linear guide device, and more particularly to a linear guide device for achieving smooth circulation of preloaded balls.

[Conventional technology]

Conventional linear guide devices of this type include those shown in FIGS. 4 and 5.

This is composed of a guide rail 1 formed by extending one row of axial ball rolling grooves 3 on both sides and a slider 2 movably fitted on the guide rail 1. There is.

The slider 2 includes a slider main body 2A in which a ball rolling groove 4 facing the ball rolling groove 3 of the guide rail is provided on the inner side surface, and a ball returning passage 5 parallel thereto is provided in the wall thickness, and a slider returning body 2A. 5 is provided with a curved path 6 that is curved in a semi-circular shape and that connects the ball rolling grooves 3 and 4 with each other.
An end cap 2B joined to the end of A, and a plurality of balls 7 rotatably inserted in the ball rolling grooves 3 and 4, the ball returning passage 5 and the curved passage 6 facing each other. There is.

A preload is applied to the balls 7 in order to remove play between the guide rail 1 and the slider 2 and increase rigidity. Therefore, in general, the opposing ball rolling grooves 3, 4
The diameter of the ball 7 has an interference with respect to the width dimension of the interval of the ball rolling path formed in (1). Depending on the size of the tightening margin, slight preload, light preload, medium preload, heavy preload, etc.
Various preload loads are set.

In the case of a single-row groove linear guide device, the load is light, and the preload is a slight to medium preload.

3a is a retainer clearance groove formed on the bottom of the ball rolling groove 3, 8 is a wiper seal that wipes and seals the ball rolling groove 3, and 9 is a ball when the slider 2 is removed from the guide rail 1. A retainer for holding 7 so as not to fall off from the ball rolling groove 4, 10 is a mounting screw for fixing the end cap 2B to the slider body 2A, 11 is a screw hole thereof, 1
Reference numeral 2 is an insertion hole for a mounting screw for fixing the guide rail 1 to the base, and 13 is a screw hole for a mounting screw for fixing the driven body to the slider.

Reference numeral 14 is a guide member having a semicircular cross section, which is fixed to the end surface of the slider body 2A so as to form the inner peripheral surface of the curved path 6.

[Problems to be solved by the device]

However, in the above-mentioned conventional example, when the preload is set excessively, the frictional force between the ball rolling grooves 3 and 4 and the ball 7 increases sharply, and the small-sized office machine or the like used with a small driving force is used. There is a problem that it is not suitable for a light load linear guide device.

The reason why the frictional resistance of the linear guide device becomes large is that the ball rolling grooves 3 and 4 are gozic arch grooves and the ball 7
Groove structure that comes in contact with 4 points.

A joint portion 15 where the ball 7 moves from a ball rolling path, which is a load section, to a curved path, which is an unloaded section, and a ball return path.
There is a step on the surface, resulting in a lack of smooth rolling.

The groove bottom of the ball rolling groove 3 with which the ball 7 is pressed is highly rigid, and the change from the preloaded portion to the non-preloaded portion is rapid.

And so on.

The present invention has been made in view of such a conventional problem, and an object thereof is to provide a linear guide device in which an excessive frictional force is not discontinuously generated with respect to a preload setting.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention has guide rails formed by extending one row of axial ball rolling grooves on both side surfaces and extending, and is loosely fitted on the guide rails so as to be movable in the axial direction. In addition, a slider main body provided with a ball rolling groove facing the ball rolling groove of the guide rail on the inner side surface and a ball returning passage parallel to the inside is formed in the wall thickness, the ball returning passage and the ball rolling passage. An end cap provided with a curved path curved in a semi-arc shape for communicating with each other, joined to the end of the slider body, and inserted into both the opposing ball rolling grooves, the ball return path and the curved path in a freely rollable manner. In a linear guide device provided with a large number of balls, at least one of the ball rolling grooves of the slider comprises a rectangular groove, and the groove bottom end of the rectangular groove except the effective supporting portion at the central portion in the longitudinal direction. Slowly over Two wires, which are formed with a crown that is curved outwardly and are elastically deformable along the shape of the crown and have semi-arcuate curved shapes that form the inner circumference of the curved path at both ends, are provided through a spacer. The balls are vertically overlapped with each other to form a ball rolling track facing the ball rolling groove of the guide rail.

Further, between the wire and the crown surface of the groove bottom of the rectangular groove, a size commensurate with the amount of elastic deformation of the ball 7 generated when a predetermined amount of preload of the ball is applied and the amount of component processing error is added. It is good to provide a gap.

[Action]

The crown formed in the lengthwise direction of the groove bottom of the rectangular groove is gently curved outwardly toward the groove end except for the effective supporting portion at the center. Then, two wires that are vertically stacked with a spacer interposed therebetween constitute a ball rolling trajectory that is elastically deformable along the crown shape.

Therefore, when the ball diameter is increased and a preload is applied, the load is applied to the effective support portion in the central portion, but the wire is pressed by the ball 7 up to the groove end, and elastically deforms along the crown shape to bend the groove. The width is expanded. As a result, the preload is gradually reduced toward the end of the groove, which promotes smooth passage of the ball. Since the wire is backed up by the crown-shaped portion at the bottom of the groove, it does not bend too much.

In addition, the semi-arcuate curved shape provided at both ends of the wire,
An inner circumference of a curved path for continuously guiding the ball is formed from the ball rolling groove. Therefore, the ball moves extremely smoothly on the curved road and can make a U-turn.

The total total area of the ball contact ellipses in the ball rolling groove is much smaller than in the past, and as a result, the amount of operation slip can be reduced and the frictional resistance is greatly reduced. On the other hand, although the load capacity of the linear guide device is also reduced by that amount, it does not matter if it is for a light load.

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

1 to 3 show an embodiment of the present invention. The same or corresponding parts as in the conventional case are designated by the same reference numerals.

At least one of the ball rolling grooves 4 on the left and right sides of the slider 2 is formed as a rectangular groove 21. The groove bottom 22 of the rectangular groove 21 is provided with an effective support portion 23 over a central portion of about 1/3 in the length direction. Except for this effective support portion 23, the groove bottom 22 is gently curved outwards to reach both ends of the slider body 2A, and the crown portion 2
4 are formed. The bending shape dimension of the crown portion 24 is such that the amount of elastic deformation of the ball generated when a predetermined amount of preload (for example, a light preload to a medium preload) is applied to the ball 7 without the crown is a normal linear guide. The ball rolling groove in the device is formed so as to have the maximum bending amount of the dimension including the component tolerance tolerance.

A wire 25 made of two elastic materials is provided in the rectangular groove 21.
Is embedded. The wire 25 has a linear portion 26 extending over the entire length of the slider body 2A, and a curved portion 27 having both ends thereof curved outward in a semi-circular shape.
The straight portion 26 is elastically deformable along the shape of the crown portion 24 of the groove bottom 22. The curved shape portion 27 forms the inner circumference of the curved path 6 of the end cap 2B. The end surface 27A is in contact with the end surface of the slider body 2A.

The two wires 25 are vertically stacked with a spacer 28 therebetween, and a ball rolling track 29 functioning as the ball rolling groove 4 is formed therebetween. Spacer 28
Has a rectangular cross section and is formed in the same shape as the wire 25. The wire 25 is pushed by the ball 7 and is always in contact with the effective support portion 23 of the groove bottom 22 and the crown portion 24.

In this embodiment, only one of the ball rolling grooves on both sides serves as the ball rolling track 29, and the ball rolling groove 4 on the opposite side remains the conventional Gothic arch groove.

Next, the operation will be described.

The crown formed in the lengthwise direction on the crown portion 24 of the groove bottom 22 of the rectangular groove 21 has an effective support portion 24 at the central portion,
It is gently curved outward toward the end of the rectangular groove. The two wires 25, which are vertically overlapped with each other via the spacer 28, are elastically deformable along the crown shape of the crown portion 24.

Therefore, when the ball diameter is increased and a preload is applied to the ball 7, the effective support portion 23 at the central portion of the ball rolling track 29 is fully loaded, but is pressed by the ball 7 toward the groove end portion. The wire 25 elastically deforms and bends along the crown shape, and the groove width is expanded. As a result, the preload is gradually reduced toward the end of the groove to promote smooth passage of the ball 7. Since the wire 25 is backed up by the crown portion 24 of the groove bottom 22, it does not bend too much.

Further, the semicircular arc-shaped curved shape portions 27 provided at both ends of the wire 25 form the inner circumference of the curved path 6, and guide the ball 7 continuously and smoothly from the ball rolling track 29.
Therefore, the ball 7 moves to the curved path 6 extremely smoothly,
It makes a U-turn.

After that, the ball 7 makes a U-turn again through the ball return passage 5 and the curved path 6 on the opposite side, and repeats the return circulation of the ball rolling path formed by the ball rolling groove 3 and the ball rolling path 29 of the guide rail. .

The total total area of the ball contact ellipses in the ball rolling path is
Much smaller than before. As a result, the amount of operation slip can be reduced, and the frictional resistance is greatly reduced. On the other hand, although the load capacity of the linear guide device is reduced accordingly, it does not matter if it is used for light loads such as computer peripherals and office machines.

As shown in FIG. 3, in this embodiment, on the ball rolling raceway 29 side, only the balls 7 within the effective support portion 23 of 1/3 of the total length of the ball rolling groove receive only a predetermined preload. .
However, the ball rolling groove 4 on the opposite side remains the conventional Gothic arch groove. As a result, the slider 2 is supported while maintaining high rigidity at the apexes of the triangle, and high motion accuracy is maintained.

It is needless to say that the ball rolling grooves of the guide rails on both sides can be formed by the ball rolling tracks 29 as required.

Further, in FIG. 1, the ball row on the right side can be held by the cage.

[Effect of device]

As described above, according to the present invention, a gently curved outwardly formed crown is formed at the end of the groove bottom of the ball rolling groove of the slider, and elastic deformation is possible along the crown shape. In addition, two balls each having a semi-arcuate curved shape at both ends were vertically stacked to form a ball rolling trajectory. Therefore, by adjusting the degree of curvature of the crown, it is possible to set the amount of preload while continuously changing it, providing a linear guide device that is discontinuous with respect to preload setting and does not generate excessive frictional force. The effect of being able to do is obtained.

[Brief description of drawings]

1 is a front view of an embodiment of the present invention with an end cap removed, FIG. 2 is a sectional view taken along line II-II of FIG. 1, FIG. 3 is a plan view of the present invention, and FIG. Is a partially cutaway front view of a conventional linear guide device, and FIG. 5 is a sectional view taken along line VV of FIG. 1 is a guide rail, 2 is a slider, 2A is a slider body,
2B is an end cap, 3 is a ball rolling groove of a guide rail, 4 is a ball rolling groove of a slider, 5 is a ball return passage, 6 is a curved passage, 7 is a ball, 21 is a rectangular groove, 22 is a groove bottom, and 23 is a groove. Is an effective support portion, 24 is a crown portion, 25 is a wire, 27 is a curved portion, 28 is a spacer, and 29 is a ball rolling track.

Claims (2)

[Scope of utility model registration request] 1. A guide rail, which is formed by extending one row of ball rolling grooves in the axial direction on each side surface, and is extended on the guide rail so as to be movable in the axial direction. A slider main body provided with a ball rolling groove facing the rolling groove on the inner side surface and a ball returning passage parallel to this inside in a wall thickness, and a semi-arcuate shape for connecting the ball returning passage and the ball rolling passage. An end cap having a curved curved path and joined to an end portion of the slider body, both ball rolling grooves facing each other, a ball return path, and a large number of balls rotatably inserted in the curved path. In the linear guide device, at least one of the ball rolling grooves of the slider is a rectangular groove, and in the longitudinal direction of the groove bottom of the rectangular groove, except for the effective supporting portion at the center, the groove gradually extends outwardly. Curved crow And two wires having a semi-arcuate curved shape that is elastically deformable along the crown shape and that forms the inner circumference of the curved path at both ends are superposed vertically through a spacer, 2. A linear guide device characterized in that a ball rolling path facing the ball rolling groove of the guide rail is constituted by the wire. 2. A gap having a size commensurate with the elastic deformation amount of the ball generated when a predetermined amount of preload is applied to the ball is provided between the wire and the crown surface of the groove bottom of the rectangular groove. The linear guide device according to claim 1, which is characterized in that.