JPS6121420A - Rectilinear motion bearing - Google Patents

Abstract

PURPOSE:To simplify a ball circulating mechanism and to improve ball circulating function by forming a ball circulating path by combination of an opposite U-shaped tube body having a belt-like connecting portion with an opposed J- shaped tube body. CONSTITUTION:Tube bodies 3, 3' respectively formed by combination of a pair of an opposed U-shaped tube body 3a and an opposed J-shaped tube body 3b are disposed on the raceway table 2 of a bearing body 1. The respective tube bodies 3, 3' are covered with covers 5 to which rubber 4 is fused and fixed to the bearing body 1 by a bolt 6. The respective tube bodies 3, 3' are joined to the end surfaces of the respective raceway grooves 1a, 1b to form an endless circulating path for balls 8. A belt-like connecting portion 36 of the tube body 3a is extended along the base of the groove 2' of the raceway table 2, so that when the bearing body 1 is pulled out from the raceway table 2, the balls 8 can be retained between the raceway grooves 1a, 1b of the bearing body 1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a linear motion bearing used for guiding linear motion parts such as tables and positioning tables of machine tools.

Prior art and its problems Conventional linear motion bearings of this type are disclosed in Japanese Patent Publication No. 57-3881.
As shown in Publication No. 2, etc., a ball return hole is machined in the axial direction in the bearing body in order to circulate the balls in the axial direction, and the end of the return hole is used to change the direction of the balls. The ball is curved and covered with a return cap which has grooves for changing the direction of the ball by 180° on both outer ends thereof. Moreover, a separate ball retainer is required to prevent the balls from falling when the bearing body is pulled out from the track.

Therefore, there are disadvantages in that the number of parts increases and that time-consuming processing is required.

OBJECTS OF THE INVENTION An object of the present invention is to simplify the conventional ball circulation mechanism as described above, and to simultaneously improve the ball circulation function.

Means and Effects for Solving the Problems In order to achieve the above object, the present invention forms a ball circulation path by combining an opposing U-shaped tube body having a band-like connection portion and an opposing three-shaped tube body. This not only significantly simplifies the ball circulation mechanism, but also eliminates the need for a ball cage.Furthermore, by making the tube body of the ball deflection part arcuate, the ball circulation mechanism is significantly simplified. Functionality is also significantly improved.

Embodiments Hereinafter, embodiments of the present invention will be explained based on the attached drawings. Figures 1 and 2 show an example in which two rows of tube bodies are used, and the upper and lower parts appear symmetrically. Since this is normal, the lower half is omitted.

Reference numeral 1 is a bearing body, and 2 is a track base. Reference numerals 3 and 3' each include a pair of opposing U-shaped tube bodies 3a and an opposing three-shaped tube body 3b, and a cover 5 on which rubber 4 is baked onto the bearing body 1. is fixed with bolts 6. 7 is a spacer.

The above combination of tube bodies is divided into two parts to facilitate press molding and to facilitate the installation of the ball. Then, such a tube body is fixed to the bearing body 1 as described above, and the raceway groove 1 having a semicircular cross section is
By joining the end faces of a and lb, the ball 8 can be easily attached.
An infinite circulation path can be formed.

When assembling the balls, turn the bearing body 1 upside down and place it on an assembly jig, and as shown in FIG. 3, as shown in FIG. After stacking the spacer, the opposing U-shaped halved tubes, the ball, and the opposing 3-shaped halved tubes in this order, the cover is bolted, which is very simple.

As shown in FIGS. 2 and 3, the band-shaped connecting portion 3C of the opposing U-shaped tube body 3a extends along the bottom of the groove 2' of the way base 2, and the bearing body 1 is separated from the way base 2. When pulled out, the ball is held between the raceway groove of the bearing body 1 and functions as a ball retainer. Note that the reference numeral 3d is a ball scooping claw.

The ball direction changing portion of the tube body 3.3' is
The resistance can be significantly reduced by forming it into an arc shape as shown in FIG.

Furthermore, FIGS. 4, 5, and 6 show the case of a single row of ball grooves, and in this case, the position where the tube is divided into two parts is not a symmetrical plane because the width of the band-like connecting portion 30' is narrow.
The band-shaped connecting portion 30' is divided into two along a plane eccentric by 1/2 of the width.

The function as a pole retainer is the same as in the first embodiment. The reference numeral 3d' is a ball scooping claw. Note that the same reference numerals as in the previous description represent the same or equivalent elements.

Next, what is shown in FIGS. 7 and 8 is a case where the linear motion bearing according to the present invention is modularized. FIG. 7 shows the case of two rows of ball grooves, and FIG. 8 shows the case of a single row of ball grooves. If the bearing body 1 and the track base 2 are modularized as shown in the figure, linear motion can be easily achieved by screwing these modules to other machine parts (for example, the table and bed of a machine tool). Can be used as a bearing. In addition, also in these embodiments, the same reference numerals as in the above description represent the same or equivalent elements.

In addition, if there are two rows of ball grooves, the shape should be circular.
If it is a groove type, and if it is a single row, it is a Gothic arc groove type.
Although it is possible to receive loads equally in all four directions, the shape of the ball groove itself is not the gist of the present invention, and any configuration may be used.

Further, in the illustrated embodiments, the tube bodies are arranged parallel to the bottom surface of the track base, but they may be arranged at an angle.

Effects of the Invention Since the present invention is constructed as described above, not only the return camp knob that was conventionally required is not required, but also secondary processing such as a slit in the main body for attaching the return camp is unnecessary. This also eliminates the need for curved surface machining of the ball entry/exit portion of the main body.

In addition, there is no need to separately provide a pole retainer (by making the shape of the direction changing part of the ball into an ideal arc shape, the resistance to the direction change of the ball is significantly reduced. By applying a coating, the ball can be made more slippery.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a partial vertical cross-sectional view of the first embodiment with the lower half omitted;
The figure is a sectional view taken along the line nn of Fig. 1, Fig. 3 is a partial perspective view of the first embodiment, and Fig. 4 shows the second embodiment.
5 is a sectional view taken along the line V-V of FIG. 4, FIG. 6 is a partial perspective view of the second embodiment, and FIGS. 7 and 8 show other embodiments. These are sectional views corresponding to FIGS. 1 and 4, respectively. 3a... Opposed U-shaped tube body 3b... Opposed J-shaped tube body 3c, 3c'... Band-shaped connection agent Patent attorney Yuyosuke - 2 others Figure 1 ■'' Figure 3 Figure 4 V” Figure 7 Figure 8

Claims (1)

[Claims] A linear motion bearing characterized in that a ball circulation path is formed by combining an opposing U-shaped tube body having a band-like connection portion and an opposing J-shaped tube body.