JPH0438931B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a linear motion bearing used in slide tables of machine tools, other measuring instruments, slide parts of press machines, and the like.

B. Prior art In general, in mechanical devices that perform linear motion such as slide tables of machine tools, other measuring instruments, slide parts of press machines, etc., rolling element circulation type that can take an infinite sliding stroke is used. Linear motion bearings are often used.

As shown in FIGS. 1 to 3, the structure of the conventional linear motion bearing of the rolling element circulation type as described above is as follows: Rolling grooves 2 are formed on both sides, and a bearing body 3 having a U-shaped cross section is straddled over the track rail 1, and the rolling grooves 2 of the track rail 1 and the raceway grooves 2 of the track rail 1 are formed on the inner peripheral surface of the bearing body 3. A rolling groove 4 is formed in correspondence with each other, and a return hole 5 penetrating through both end faces is formed in an adjacent portion separated from the rolling groove 4 by a predetermined distance, and a return hole 5 is formed in both end faces of the bearing body 3. A cover body 6 is attached and fixed, and a reversal groove 7 is formed in the cover body 6 to communicate the rolling groove 4 of the bearing body 3 and the return hole 5, and furthermore, a reversing groove 7 that communicates the rolling groove 4 of the bearing body 3 and the return hole 5 is formed in the lid body 6. 5 and lid body 6
A large number of balls 9, some of which are held by cages 8, are accommodated in each ball circulation path formed by reversing grooves 7.

By the way, in the above-described conventional rolling element circulation type linear motion bearing, a method of configuring a reversing path that connects the rolling groove 4 of the bearing body 3 and the return hole 5 is shown in FIGS. 4 to 6. As shown in FIG. 2, a fitting groove 10 is formed in the reversing groove 7 of the lid body 6 across the reversing groove 7, and an inverting core 11 having an arcuate cross section (cylindrical semicircle) is fitted into this fitting groove 10. It is constructed by combining them. Therefore, a fitting groove 10 is formed in each of the reversing grooves 7 of the lid body 6, and a reversing core 1 is formed in each of the fitting grooves 10.
Since it is necessary to fit and combine 1, inverted core 11
Errors such as slight deviations are likely to occur in positioning, and this has the disadvantage that it is difficult for the balls 9 to roll smoothly.

C. Purpose of the Invention The present invention provides a rolling element circulation system that simplifies the structure and facilitates manufacturing by eliminating the need for a reversing core, and at the same time allows balls to roll smoothly. The purpose of this invention is to provide a type of linear motion bearing.

D. Structure of the Invention The present invention provides a ball reversing path in which a guide is integrally formed to protrude over the entire length of both sides of the reversing groove of the lid body, and the distance between the open ends of the guide is made smaller than the diameter of the ball. This is a characteristic feature.

Function By forming the ball reversing path with the reversing groove of the lid and the guides formed protrudingly over the entire length on both sides, the reversing core that was conventionally necessary can be omitted.

E. Embodiment FIGS. 7 to 9 show an example of a linear motion bearing of the rolling element circulation type according to the present invention. Reference numeral 12 denotes a long track rail of a predetermined length and a rectangular cross section, and the upper surface and both end surfaces of the bearing are shown in FIGS. A rolling groove 13 is formed in each longitudinal direction. Reference numeral 14 denotes a bearing body having a U-shaped cross section and extending over the track rail 12, and has rolling grooves 15 formed on the inner circumferential surface facing the track rail 12 in correspondence with the rolling grooves 13 of the track rail 12, respectively. At the same time, return holes 16 with open end faces at both ends are formed parallel to the rolling grooves 15 at adjacent portions separated by a predetermined distance in correspondence with the rolling grooves 15, respectively. 17 is a lid body that covers the front and rear end surfaces of the bearing body 14;
As shown in FIG. 9, a recess 18 having an arcuate side cross section is formed on the abutting surface of the recess 18, and a reversal groove 19 is formed on the bottom surface of the recess 18. A guide 20 is formed that protrudes into the recess 18, and the guide 20 and the reversing groove 19 connect the bearing body 1.
A ball reversing path 21 is configured to communicate between the rolling groove 15 of No. 4 and the return hole 16. Above guide 2
0 has the same radius of curvature as the reversing groove 19, and the width l between its open ends is a ball circulation path composed of the rolling groove 15 and the return hole 16 of the bearing body 14, and the ball reversing path 21 of the cover body 17. Balls 2 accommodated in large numbers in
The diameter is smaller than that of 2. This guide 20 can be integrally formed when the lid body 17 is formed by injection molding.

In the drawings, 23 is a bolt that fixes the lid 17 to the bearing body 14, 24 is a retainer that holds the balls 22, and 25 is a seal member that seals the inside of the bearing.

In the linear motion bearing having the above structure, since the ball reversing path 21 can be formed only by the lid 17, the conventional reversing core can be dispensed with, and the structure of the bearing can be simplified. In addition, in the ball reversing path 21 formed by integrally forming the guide 20 and protruding over the entire length on both sides of the rolling groove 19 of the lid body 17, there is no possibility of misalignment with the rolling groove 15 or the return hole 16 of the bearing body 14. The balls 22 roll smoothly without any errors, and the bearing body 14 moves smoothly. Then, a gap is created by the recess 18 on the inner diameter side of the ball reversing path 21 where the reversing core was conventionally placed.
A considerable amount of grease can accumulate within this gap. Furthermore, by injection molding the lid body 17 from synthetic resin, it can be manufactured easily and with high precision.

F. Effects of the Invention According to this invention, the structure can be simplified by eliminating the conventional inverted core, and the rolling elements can roll smoothly, allowing the bearing body to move smoothly with a small amount of power. It can be widely applied to various mechanical devices that require linear motion. In addition, a large gap can be formed on the inner diameter side of the ball reversing path, and a considerable amount of grease can be stored in this gap to improve the lubrication performance of the bearing, thereby significantly extending and improving the life of the bearing. Furthermore, by injection molding the lid using synthetic resin as a material, it can be manufactured easily and with high precision, and a highly accurate linear motion bearing can be provided at low cost.

[Brief explanation of drawings]

Figures 1 to 3 show conventional linear motion bearings, with Figure 1 being a partially cutaway front view, Figure 2
The figure is a partially sectional plan view, and FIG. 3 is a plan view taken along line A--A in FIG. 1. FIG. 4 is a side view of a conventional lid body, FIG. 5 is a side view taken along line B--B in FIG. 4, and FIG. 6 is an oblique view of an inverted core. 7 and 8 show an example of a linear motion bearing according to the present invention, with FIG. 7 being a partially sectional front view and FIG. 8 being a partially sectional plan view. 9th
The figure is a side view of the lid according to this invention. 12... Track rail, 13... Rolling groove, 14...
... Bearing body, 15 ... Rolling groove, 16 ... Return hole,
17... Lid body, 18... Recess, 19... Inversion groove,
20...Guide, 21...Ball reversal path, 22...
…ball.

Claims (1)

[Claims] 1. A track rail with rolling grooves formed in the longitudinal direction on the top surface and both side surfaces, and rolling grooves formed in the longitudinal direction on the inner circumferential surface corresponding to the rolling grooves of the track rail, respectively,
and a bearing body having a return hole penetrating through both end faces formed in an adjacent part separated from the rolling groove by a predetermined distance, and a bearing body that is attached and fixed to both end faces of the bearing body, and the rolling groove and the return hole. The balls are housed in a ball circulation path consisting of a lid body having an arc-shaped reversing groove communicating with the bearing body, a rolling groove of the track rail, a rolling groove and a return hole of the bearing body, and a reversing groove of the lid body. In the linear motion bearing, which consists of a ball and slidably straddles the bearing body on the track rail via the ball, a guide integrally protrudes over the entire length of both sides of the reversal groove of the lid body. A linear motion bearing characterized in that the distance between the open ends of the guide is smaller than the diameter of the ball to form a ball reversal path.