JP3244239B2 - Stroke bearing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stroke bearing applicable to precision measuring instruments, precision machining machines, industrial robots and the like.

[0002]

2. Description of the Related Art Conventionally, non-infinitely circulating linear ball bearings (stroke bearings) have a limited moving operation distance (stroke) unlike infinitely circulating linear ball bearings. There is a tendency to be shifted toward one end of the track, which hinders a smooth reciprocating operation. In order to solve these problems, a stroke bearing has been proposed that uses a motion spring or an interlocking mechanism to limit the movement of the cage to prevent the bearing ball from shifting to one stroke end. Have been.

[0003]

However, since the interlocking mechanism is complicated and occupies a large space, it is difficult to incorporate these mechanisms into a small stroke bearing. The present invention has been made in order to improve such inconvenience, and it is an object of the present invention to provide a stroke bearing that prevents a phenomenon that hinders a smooth stroke operation due to a bias of a bearing ball to one stroke end. Aim.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a stroke bearing having a hollow bearing body through which a guide shaft is inserted and which can move a specified distance relatively to the guide shaft. In the bearing main body, on the inner wall surface where the guide shaft is inserted, in the longitudinal direction of the bearing main body at equal intervals, a linear groove-shaped track in which a large number of bearing balls are disposed is formed. One end side or the other end side is alternately deflected by a minute distance in the diametrical direction of the bearing body passing through the bearing body axis. Further, the present invention provides a stroke bearing having a hollow bearing main body, which is capable of moving a specific distance relative to the guide shaft while inserting the guide shaft, wherein the bearing main body has an inner wall surface through which the guide shaft is inserted. In the longitudinal direction of the bearing main body at equal intervals, a linear groove-shaped track in which a number of bearing balls are arranged is formed, and one end side or the other end side of adjacent tracks is centered on the bearing main body axis.
Characterized in that it is alternately deflected a minute distance in the circumferential direction of the circle . Further, the present invention provides a stroke bearing having a hollow bearing main body that can be moved relative to the guide shaft by a specific distance while inserting the guide shaft, wherein, on the inner wall surface of the bearing main body, the guide shaft is inserted. A linear groove is formed in the longitudinal direction of the bearing body at regular intervals, and a groove is formed on the guide shaft side corresponding to the groove, and a large number of grooves are formed by the groove on the bearing body side and the groove on the guide shaft side. And the other end of the adjacent track is alternately deflected by a small angle from a position parallel to the axis of the bearing body. Features.

[0005]

The load on the bearing ball varies depending on the position on the track because the axis of the track of the bearing ball is deflected by a small angle from the position parallel to the axis of the bearing body. Therefore, as the reciprocating operation is repeated, the bearing balls are deviated in the direction of less load. However, the adjacent raceways alternately deflect one end or the other end of the race from a position parallel to the axis of the bearing body by a small angle, so that the bearing balls on each raceway alternately It is possible to avoid the danger of gathering at one stroke end at one end side or the other end side of the track, and to keep the smooth operation at all times.

[0006]

Next, an embodiment of a stroke bearing according to the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a stroke bearing 1. The stroke bearing 1 has a bearing main body 3 through which a guide shaft 2 is inserted and which can move a specified distance with respect to the guide shaft 2. The bearing body 3 has a hollow cylindrical shape and has a guide shaft 2.
On the inner peripheral surface 4 corresponding to the shape of the above, linear groove-shaped orbits B1, B2, B3, B4, in which a number of bearing balls 5 are arranged in the longitudinal direction of the bearing body 3 at equal intervals along the inner periphery. B
5 and B6 (see FIG. 2), and the axes B1o, B2o, B3o, B4o, B5o, and B6o of the orbits B1 to B6.
From the position parallel to the axis A of the bearing main body 3 is minutely deflected. In this case, in the tracks B1 to B6, the tracks B1 and B2 adjacent to each other, the track B2
And orbit B3, orbit B3 and orbit B4, orbit B4 and orbit B
5, the track B5 and the track B6, and the track B6 and the track B1 alternately deflect one end side or the other end side by a small angle from a position parallel to the axis A of the bearing main body 3.

Here, the axes B1o to B6 of the orbits B1 to B6
A specific example of the deflection direction o will be shown and described. First, as shown in FIG.
The shaft centers B1o, B3o, B5o of the shafts 3 and B5 are made to expand in the diameter direction of the bearing body 3 passing through the shaft center A toward the right end of the bearing body 3, while the shaft centers B2o of the tracks B2, B4 and B6. , B4o, and B6o are made to expand in the diametrical direction of the bearing main body 3 passing through the axis A as going to the left end of the bearing main body 3 in reverse. That is, in this example, the deflection direction is set so that the deflection direction is the diametric direction of the bearing body 3 passing through the axis A of the bearing body 3 and the deviation d ₁ at the left and right ends of the bearing body 3 is several microns to several tens microns. Have been.

As shown in FIG. 4, the axis B1o of the tracks B1, B3 and B5 with respect to the axis A of the bearing main body 3,
B3o, B5o are placed at the left end of the bearing body 3 in the clockwise direction, and the shaft centers B2o, B4o, B of B2, B4 and B6 are clockwise.
6o can be deflected clockwise at the right end of the bearing body 3. That is, in this example, the axes B1o to B6o of the orbits B1 to B6 on the circumference of a circle centered on the axis A of the bearing body 3 are deflected by a small distance along the circumference. In this case, the deviation d ₂ at the left and right ends of the bearing body 3 is also set to be minute (several microns to several tens microns) as compared with the diameter of the bearing ball 5.

Since the stroke bearing 1 of the present invention is constructed as described above, if each bearing body 3 is combined with the guide shaft 2 so that there is no residual pressure near one end of each of the tracks B1 to B6, a minute stroke can be obtained. Is repeated, the bearing balls 5 on each adjacent track B1 to B6
Tends to move toward one end side or the other end side of the tracks B1 to B6 alternately, so that the bearing ball 5 is biased to one of the stroke ends, so that the reciprocating operation of the bearing body 3 Can be avoided.

Although the embodiment of the stroke bearing according to the present invention has been described above, the invention can also be implemented by using a ball spline 10 as shown in FIGS. In the ball spline 10, components having substantially the same configuration as the components of the stroke bearing 1 according to the above-described embodiment are denoted by the same reference numerals. In this case, in the ball spline 10, linear grooves 11 are formed on the inner peripheral surface 4 of the bearing body 3 at regular intervals in the longitudinal direction of the bearing body 3, and the grooves 11 are formed on the guide shaft 2 side.
Are formed, and the grooves 11 on the bearing body 3 side and the splines S on the guide shaft 2 side are used to form the orbits B1 to B6 for rolling and moving a large number of the bearing balls 5.
The axes B1o to B6o of the tracks B1 to B6 are deflected by a small angle from a position parallel to the axis A of the bearing main body 3. The deflection directions of the tracks B1 to B6 are the same as those of the stroke bearing 1 according to the above-described embodiment. One end or the other end of the track B5, the track B5 and the track B6, and the track B6 and the track B1 are alternately deflected by a small angle from a position parallel to the axis A of the bearing body 3.

With such a ball spline 10,
The load applied to the bearing ball 5 is alternately dispersed by alternately deflecting the one end side or the other end side of the tracks B1 to B6 from a position parallel to the axis A of the bearing main body by a small angle. It is possible to avoid a phenomenon in which the bearing ball 5 is biased toward one of the stroke ends, thereby hindering the reciprocating operation of the bearing body 3.

[0012]

As described above, according to the present invention, one end or the other end of the raceway of the bearing ball is alternately deflected by a small angle from a position parallel to the axis of the bearing body. By dispersing the load on the bearing balls alternately, it is possible to avoid the phenomenon that the reciprocating operation of the bearing body caused by the bearing balls being biased to one of the stroke ends in the track is hindered, and the smooth operation is always performed. Can be maintained. Therefore, a special mechanism for restricting the movement of the cage is not required unlike the related art, and it is only necessary to deflect the trajectory of the bearing ball. Therefore, it is possible to suppress the manufacturing cost without complicating the configuration. Can be.

[0013]

[Brief description of the drawings]

FIG. 1 is an explanatory longitudinal sectional view showing one embodiment of a stroke bearing according to the present invention.

FIG. 2 is a sectional view of the stroke bearing shown in FIG. 1 taken along line XX.

FIG. 3 is a schematic perspective explanatory view showing one deflection example of a trajectory of a bearing ball of the stroke bearing shown in FIG. 1;

FIG. 4 is a schematic perspective explanatory view showing one deflection example of a trajectory of a bearing ball of the stroke bearing shown in FIG. 1;

FIG. 5 is an explanatory longitudinal sectional view showing an embodiment of a ball spline according to the present invention.

FIG. 6 is a sectional view taken along line XX of the ball spline shown in FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stroke bearing 2 Guide shaft 3 Bearing main body 4 Inner peripheral surface 5 Bearing ball A Axis B1-B6 Track B1o-B6o Axis 10 Ball spline 11 Groove S Spline

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Claims (3)

(57) [Claims] 1. A stroke bearing having a hollow bearing body through which a guide shaft is inserted and which can be moved by a specific distance relative to the guide shaft, wherein the inner wall surface of the bearing body, through which the guide shaft is inserted, is provided. In the longitudinal direction of the bearing body at equal intervals, a linear groove-shaped track in which a number of bearing balls are arranged is formed, and one end side or the other end side of the tracks adjacent to each other,
Small distance alternately in the diameter direction of the bearing body passing through the bearing body axis
Stroke bearing is characterized in that by releasing the deflection. 2. A stroke bearing having a hollow bearing main body through which a guide shaft is inserted and which is movable relative to the guide shaft by a specific distance, wherein the inner wall surface of the bearing main body through which the guide shaft is inserted is provided. In the longitudinal direction of the bearing body at equal intervals, a linear groove-shaped track in which a number of bearing balls are arranged is formed, and one end side or the other end side of the tracks adjacent to each other,
Small distance alternately in the circumferential direction of the circle centered on the bearing body axis
Stroke bearing characterized by being deflected . 3. The guide shaft is inserted through the guide shaft and
It has a hollow bearing body that can move a specific distance
In a stroke bearing, a guide of the bearing body is provided.
On the inner wall surface where the shaft is inserted,
A linear groove is formed on the guide shaft side.
The grooves on the bearing body side and the guide shaft
A large number of bearing balls are rolled by the side grooves
Track, one end of adjacent tracks or other
Cross the end from a position parallel to the bearing body axis.
Stroke bearings characterized by mutually deflected by a small angle .