JPH116524A - Linear bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable smooth movement of a slider even when the rail is not accurately parallelly arranged. SOLUTION: Two inner orbits 16, 20 opposed to each other are formed on a linear rail having a C-shaped section. A slider has at least three rollers 14a, 14b, 14c which are in alternative contact with the orbits. Outer peripheral surfaces of the rollers 14a, 14b, 14c have semi-circular arch form. The orbit 16 has a V-shaped section, and is composed of angularity formed two surfaces 16a, 16b. The orbit 20 has an arcuate section, having a larger radius than that of the semi-circular arch of the roller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear bearing employed in various technical fields for performing a linear motion of a machine part while minimizing friction.

[0002]

2. Description of the Related Art As a conventional linear bearing, a cross section C
There is an example in which two confronting parallel internal trajectories are formed on a character-shaped straight rail. In this case, three or more rollers are provided on the slider, and the rollers are alternately brought into contact with one of the two tracks to perform a linear motion. These internal orbits have a V-shaped cross section, and are fitted with a truncated pyramid-shaped or elliptical roller whose outer peripheral surface has a truncated pyramid-shaped cross-section, and are rotated. As another example, there is a linear guide having a C-shaped cross section in which both the upper and lower two or at least one of the inner tracks are formed flat.

[0003]

In either case, the problem is that the trajectory must be increased to feed the slider at the correct angle to the axis of the roller and to feed the slider along the axis of the roller. In this case, the roller must be properly grounded. For heavy loads, two opposing parallel rails are used, each rail having at least one slider with a plurality of rollers. In these arrangements, the two rails must be arranged completely parallel, which is difficult and expensive to implement. In addition, it is often impossible to make the two rails completely parallel due to factors such as thermal expansion and load deformation. In addition, the inner orbit is 2
In the linear bearing having a V-shaped cross section, the slider cannot be properly fitted to the inner race, and the linear bearing having one flat inner race cannot support the roller properly.

An object of the present invention is to solve the above-mentioned drawbacks and to provide a linear bearing in which a slider can move smoothly even if the rail is deformed due to heat expansion or load and the right and left parallelism is lost.

[0005]

In order to achieve the above-mentioned object, according to the present invention, two straight rails having a C-shaped cross section are provided so as to face left and right parallel to each other, and two inner tracks are vertically opposed to each rail. Formed. A slider having three or more rollers alternately contacting these upper and lower internal tracks is provided, and the outer peripheral surface of the roller has an arc-shaped cross section with a radius r. Further, one of the upper and lower inner orbits has a cross section of V
In the form of a letter, the other internal track forms a cross section in the shape of an arc of radius R and has a length longer than the radius r of the contour of the roller. Here, the radius r of the contour of the outer peripheral surface of the roller may be set to half the thickness of the roller in the axial direction. Further, the radius R of the cross section of the internal raceway having the circular cross section is a length from the center of the circular arc of the circular cross section of the outer peripheral surface of the roller in contact with the internal raceway having the V-shaped cross section to the raceway surface of the internal raceway having the circular cross section. Good to go.

[0006]

Next, an embodiment of a linear bearing will be described with reference to the drawings. FIG. 1 is a perspective view of the linear bearing of the present invention. FIG. 2 is a view of the linear bearing of FIG. 1 reduced in scale and viewed from the inside. FIG.
FIG. 3 is a cross-sectional view of the linear bearing taken along the line III. In FIG. 3, the rollers are in the normal position. That is, the symmetry plane of the roller completely coincides with the center plane of the V-shaped orbit. FIG. 4 is a sectional view of a linear bearing similar to FIG. In FIG. 4, the rail is deformed, so that the plane of symmetry of the roller is inclined at an angle to the center plane of the V-shaped trajectory.

The linear bearing according to the present invention is generally designated by the reference numeral 10, and comprises a linearly moving linear rail 12 and a slider (not shown) having three rollers 14. The three rollers are represented by reference numerals 14a, 14b and 14c. The straight rail 12 has a C-shaped cross section, and inside the C-shaped wing, opposed internal tracks 16 and 20 are provided.

[0008] The inner track 16 shown at the bottom of the figure,
It consists of inclined surfaces 16a and 16b. This inclined surface 16a, 1
6b is symmetrical with respect to a vertical center plane, and this center plane is indicated by a in FIGS. 3 and 4. The inclined surfaces 16a, 16b
They are connected by a surface 17. The shape of the surface 17 is not particularly limited, but is often an arc surface. Inclined surfaces 16a, 16b
Is α.

The other internal track 20 has a shape corresponding to a part of a cylindrical surface. That is, as shown in FIGS. 3 and 4, the cross-sectional shape of the inner track 20 is an arc, and the radius of the arc is represented by R.

A slider roller 14a according to the present invention,
The outer peripheral surfaces of 14b and 14c are a part of an arc having a radius r of half the thickness of the roller, and preferably a semi-arc having a radius r. When the outer peripheral surfaces of the rollers 14a, 14b, and 14c have a radius r, the rollers 14a and 14c always contact at two points of the inclined surfaces 16a and 16b of the V-shaped orbit.
This minimizes friction without affecting rail deformation. The radius R of the arcuate track 20 at the top of the rail is much longer than the radius r described above. Therefore, the contact of the roller 14b is always a point contact.

The orbit surface of the arc-shaped orbit 20 is as follows. In a state where the rollers 14a, 14b, and 14c are normal and are not inclined with respect to the rail, the rollers 14a, 14b, and 14c are not inclined.
The plane of symmetry b of b, 14c is the plane 16a, 16 of the V-shaped orbit.
b is on the center plane a. In FIG. 4, due to the deformation of the rail, the symmetry plane b of the rollers 14a, 14b, 14c does not coincide with the center plane a of the surfaces 16a, 16b of the V-shaped track.
Since the outer surfaces of the rollers 14a, 14b, and 14c having the radius r intersect with the center surface a at the center point O of the circular arc of the outer surface of the rollers 14a, 14b, and 14c, the outer surfaces of the rollers 14a, 14b, and 14c having the radius r have a V-shaped orbit. Points 16a and 16b. Here, the length of the radius R is equal to the length connecting the point O and the trajectory 20.

In the linear bearing defined in this manner, the slider can be tilted to the symmetry plane b defined by the value β (see FIG. 4) without changing the specified value of the load condition or the play of the roller. Becomes

In the above embodiment, the number of rollers is three. However, the number of rollers is not limited to three, and three or more rollers may be brought into alternate contact with the two internal tracks.

[0014]

According to the present invention, one inner track of the rail is V-shaped, and the other inner track is a circular arc having a diameter larger than the radius of the semi-circular protrusion of the roller. Since the rollers are in contact with these two internal tracks alternately, the slider can move smoothly even if the rail expands due to heat or is deformed by the load and becomes non-parallel.

[Brief description of the drawings]

FIG. 1 is a perspective view of a linear bearing of the present invention.

FIG. 2 is a front view of the linear bearing of FIG. 1;

FIG. 3 is a sectional view of the linear bearing taken along the line III-III in FIG. 2;

FIG. 4 is a cross-sectional view of the linear bearing taken along the line III-III as in FIG. 3, showing a state in which rollers are inclined with respect to the rail due to deformation of the rail.

[Explanation of symbols]

 12 Linear rails 14a, 14b, 14c Roller 16 V-shaped internal track 16a, 16b Inclined surface 20 Arc-shaped internal track

Claims (3)

[Claims] 1. Two straight rails having a C-shaped cross section are provided so as to face left and right parallel to each other, and each rail has two internal tracks (1).
6) and (20) are formed facing each other up and down, and a slider having three or more rollers (14) that alternately contact these upper and lower internal tracks is provided. One of the upper and lower inner tracks (16) has a V-shaped cross section, and the other inner track (20) has a cross section formed in an arc having a radius R, and has a radius R. A linear bearing in which the length of R is longer than the radius r of the contour of the roller. 2. A linear bearing according to claim 1, wherein the radius of the contour of the outer peripheral surface of said roller is half the axial thickness of said roller. 3. The radius R of the cross section of said inner track (20) is:
The length from the center (O) of the arc of the circular cross section of the outer peripheral surface of the roller (14) in contact with the other internal track (16) to the track surface of the internal track (20) is characterized in that it is equal to the length. Item 7. The linear bearing according to Item 1.