JP2556901B2 - Manufacturing method of linear motion ball bearing - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of manufacturing a linear motion ball bearing.

[Conventional technology]

The linear motion ball bearing is a mechanism in which several rows of balls receive the load from the load side through the return circuit of the ball retainer to the load side again while undergoing endless circulation motion. In that case, a light and reciprocating rectilinear motion can be obtained with the minimum frictional resistance based on the close and smooth rolling contact, and the contribution to energy saving is immeasurable.
It is widely used in industrial robots, various measuring instruments, medical instruments, computer terminal equipment, and so on.

The linear motion ball bearing is constructed as shown in FIGS. 9 to 11. FIG. 9 is a longitudinal sectional view, FIG. 10 is an upper half transverse sectional view, and a sectional view taken along line XX of FIG. Half shows the side surface seen from the P direction of FIG. In these figures, 1 is a linear motion ball bearing outer cylinder made of carbon steel (hereinafter referred to as an outer cylinder), 2 is a ball holder made of plastic, 3 is balls, 4, 5 is a ball holder 2
It shows a retaining ring made of carbon steel for fixing the inside of the outer cylinder 1.
FIG. 11 is a partial top view of the ball retainer 2 unfolded and viewed from the outer surface. The ball retainer 2 is provided with a ball retaining portion 5, and the ball retaining portion 5 has an opening on the inner side surface. It is composed of a concave surface portion 5a which is not formed and a slit portion 5b having a slit-like opening on the inner side surface thereof. The concave surface portion 5a and the slit portion 5b are provided along the axial direction of the ball holding portion 5, both ends of which are The ball 3 has a continuous structure, forms a circulation path for linear rolling of the ball 3, and is provided at a rotationally symmetrical position.

The ball 3 held by the ball holding portion 5 comes into contact with a linear motion shaft (hereinafter referred to as a shaft) (not shown) at the slit portion 5b, and when the relative position between the shaft and the ball 3 changes, The ball 3 rolls in the slit portion 5b and operates as a bearing by sequentially replacing the ball 3 held in the concave surface portion 5a communicating with the slit portion 5b.

The outer cylinder 1 has an inner peripheral surface 1b provided with a concave surface portion in which a plurality of concave portions are continuously inserted and a circular outer peripheral surface 1a into which the ball cage 2 is fitted.

Table 1 shows the specifications and ratings of the linear motion ball bearing manufactured by the applicant in relation to FIGS. 9 and 10. Inscribed circle diameter d, outer diameter D, width L, groove Interval B, groove bottom diameter E, groove width F, number of balls G, basic dynamic load rating Kgf, optimum dynamic load rating Kgf, basic static load rating Kgf inscribed circle diameter d is 6, 8, 10, 12, 13 , 16, 20, 25, 30, 35, 40
(Mm) is shown.

In order to manufacture the outer cylinder 1, the inner surface of the outer cylinder material having a circular cross section is cut and manufactured.

[Problems to be Solved by the Invention]

The demand for linear motion ball bearings has become more and more widespread, and recently, linear motion ball bearings having a long length, for example, double the length of conventional linear motion ball bearings have been required.

However, conventionally, the outer cylinder of the linear motion ball bearing is manufactured by cutting the inner surface of the outer cylinder material having a circular cross section, as described above. There is a problem in terms of accuracy and workability when the cutting method is used, and countermeasures have been required.

The present invention can eliminate such problems and meet the demand for long-length linear motion ball bearings. It is intended to provide a highly accurate linear motion ball bearing with good workability.

[Means for solving problems]

The structure of the present invention, which has been adopted to solve the above-mentioned problems, is an outer cylinder formed of a cylindrical body having a plurality of concave surfaces which are continuously extended on the inner peripheral surface in a manner of a central axis and constitute a return path of a ball. In a method for manufacturing a linear motion ball bearing in which a ball retainer in which a circulation path is formed for linear rolling of a ball is inserted and manufactured, an outer cylinder material having a uniform thickness is used. A first step of creating, and a flower-shaped cross section formed by arranging a plurality of arcs whose center points are arranged on the same radius centering on the central axis and arranged in rotational symmetry with respect to the central axis. By a cold forming process using a male die having a male die and a female die having a substantially similar shape to the flower-shaped cross section of the male die, it has a length capable of arranging a plurality of the ball cages and has a uniform thickness. A second step of creating a flower-shaped molded product having; A third step of cutting the outer peripheral surface of the flower-shaped molded body having a uniform thickness formed in the second step into a circular shape to form the outer cylinder made of a thick body having an outer cylindrical shape, And a fourth step of axially inserting a plurality of the ball retainers into the outer cylinder formed in the third step.

[Action]

In the invention of this application, in the first step, a cylindrical material having a uniform thickness is cold-formed, for example, drawn by using a mold having the same shape as the inner peripheral surface of the outer cylinder. Since the inner peripheral surface of the outer cylinder can be formed, it is possible to form the outer cylinder having a high accuracy of the inner peripheral surface even if the length is long.

Then, in the first step, the outer circumference of the cylindrical body that has been cold-formed, for example, drawn and processed into a shape similar to the inner peripheral surface of the outer circumference, is cut into a circular shape in the second step.

That is, since it is possible to produce the inner peripheral surface of the outer cylinder, which is difficult to cut, by cold forming, for example, drawing, and the outer peripheral surface is processed by cutting, it is possible to increase the length of the outer cylinder. It is possible to perform accurate machining with good workability.

In this manufacturing method, a female die having a flower-shaped cross section composed of a plurality of concave surfaces arranged in a row in the cross section of the outer cylinder and a male die made of cemented carbide and having a flower-shaped cross section similar to the female die are used. Since cold-working, for example drawing, is performed on the outer cylinder material consisting of a cylindrical body having a uniform wall thickness, the inner peripheral surface of the long outer cylinder is processed without the need for subsequent processing. can do.

Since the outer cylinder manufactured by the manufacturing method of the present invention has good working accuracy and workability, it is possible to provide a precise and inexpensive linear motion ball bearing, which satisfies a wide range of demands. be able to.

〔Example〕

 Hereinafter, examples will be described.

1 and 2 are an upper half longitudinal sectional view and an upper half transverse sectional view of an embodiment of the present invention, FIG. 2 shows a YY cross section of FIG. 1, and a lower half is a first sectional view. FIG. 3 shows a side surface viewed from the Q direction, and FIG. 3 shows a partial upper surface of the ball cage 2 when it is developed and viewed from the outer surface. 9 and 10 and 11 in these figures
The same parts as those in the drawings are denoted by the same reference numerals.

Table 2 shows the specifications and ratings of the linear motion ball bearing of the embodiment shown in FIG. Shown in relation to FIG. 2 and FIG.
For the same items as in the table, the inscribed circle diameter d is 6, 8, 10, 1
It is shown for the case of 2, 13, 16, 20, 25, 30 (mm).

In the linear motion ball bearing of this embodiment, the width L'with respect to the inscribed circle diameter d is twice that in Table 1 (hereinafter, such a linear motion ball bearing is referred to as a double type). The double type linear motion ball bearing of this embodiment is, for example, as shown in FIGS. 1 and 2, in the double type linear motion ball bearing outer cylinder 1 of the conventional type shown in FIGS. 9 and 11. Two ball retainers 2 of a linear motion ball bearing are inserted and configured.

This double type linear motion ball bearing has a maximum accuracy of 3μ when using two conventional linear motion ball bearings in parallel, while a maximum accuracy of 3μ is 3μ.
Since the accuracy can be set to μ, a linear motion ball bearing having extremely high accuracy can be obtained. In addition, the number of seals, rings, etc. is reduced structurally, so the price is cheaper in combination with the ease of assembly. Furthermore, the double type can withstand high loads and has high rigidity.

A linear motion ball bearing having these excellent characteristics can be obtained by using the method for manufacturing a linear motion ball bearing of the present invention, and its embodiment will be described below.

FIG. 4 is an explanatory view of the manufacturing method of one embodiment, and is a cross-sectional view in different forming steps of the outer cylinder, and FIGS. 5 and 6 are a vertical cross-sectional view and a cross-sectional cross section of a main part to be used, respectively. FIG. 7, FIG. 7 and FIG. 8 are a longitudinal sectional view of the male mold and an explanatory view of a lateral cross section of the main part.

First, prepare a cylindrical body 6a as shown in FIG. 4 (a), which is made of carbon steel having an outer diameter of 50.8 mmφ and a wall thickness of 6.5 mm, which has been pre-drawn and has an outer diameter of 48 mmφ and a wall thickness of 6 mm. When the drawing process is performed using the female die 7 and the male die 8 as shown in FIGS. 5 to 8, the cylindrical body 6a having an inner diameter of 48 mmφ is expanded, and the outer cylinder 1 as shown in FIG. A flower-shaped cylindrical body 6b having the same shape as the inner peripheral surface 1b and a constant wall thickness is formed. In this step, the inner peripheral surface of the outer cylinder 1 does not require cutting work, and can be created only by drawing work. At this time, details that cannot be processed by drawing,
Ball cage 2 for fixing the ball cage in the outer cylinder 1
The grooves for fixing the retaining rings 4 and 5 provided at both ends of the are processed.

Next, as shown in FIG. 4 (c), the outer periphery of the flower-shaped cylindrical body 6b shown in FIG. The cylinder 6c is obtained. And
A circumferential groove for fixing is formed in a part.

In the manufacturing method of the outer cylinder of the present invention, in the first step, the cylindrical body 6a having a constant wall thickness is manufactured into the flower-shaped cylindrical body 6b having a constant wall thickness by cold forming, for example, drawing. Therefore, the outer cylinder having a long length can be easily manufactured with high accuracy.

By this first step, the inner peripheral surface of the outer cylinder having a long length such as the double mold can be easily processed with high accuracy, and thus the flower-shaped cylindrical body 1b manufactured in this manner can be manufactured. Since the outer circumference can be cut to form the outer cylinder 1, the manufacturing is easier and the length can be reduced as compared with the conventional method of cutting the inner peripheral surface of the cylindrical body to manufacture the flower-shaped inner peripheral surface. The long outer cylinder can be easily manufactured with high precision. In addition, it is impossible to form the cylindrical body using the female die 7 having the inner peripheral surface cylindrical shape and the female die 8 having the flower-shaped outer peripheral surface, and the first step and the second step as in the present invention. By combining with, the intended purpose can be achieved.

The method of manufacturing the linear motion ball bearing of the present invention can be carried out by using the manufacturing tool as described above, and a cemented carbide material is used for these female and male dies. For example, it is desirable to use those coated with TiN, TiC, etc. by CVD.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY The method for manufacturing a linear motion ball bearing according to the present invention can provide a highly accurate linear motion ball bearing that can meet the demand for a long linear motion ball bearing with good workability, and has an industrial effect. Is a great thing.

[Brief description of drawings]

1 and 2 are a longitudinal sectional view and a partial transverse sectional view, respectively, of a linear motion ball bearing manufactured by an embodiment of the method for manufacturing a linear motion ball bearing of the present invention, and FIG. 3 is the same ball retainer. FIG. 4 is a partial top view of the developed and viewed from the outside, FIG. 4 is an explanatory view of an embodiment of the method for manufacturing the linear motion ball bearing of the present invention,
FIGS. 6 and 6 are a longitudinal sectional view of a female mold and an explanatory view of a lateral cross section of an essential part, respectively, and FIGS. 7 and 8 are longitudinal sectional view of a male mold and an explanatory view of a lateral cross section of an essential part, respectively. FIG. 10 and FIG. 10 are a partial vertical cross-sectional view and a partial horizontal cross-sectional view, respectively, of a conventional linear motion ball bearing, and FIG. 11 is a partial top view of the same ball cage when viewed from the outside. 1 …… Linear motion ball bearing outer cylinder, 2 ……
Ball cage, 3 ... Ball, 6a ... Cylindrical body, 6b ... Flower-shaped cylinder, 6c ... Linear motion ball bearing outer cylinder, 7 ... Female type, 8 ... Male type.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-55-135226 (JP, A) JP-A-55-155922 (JP, A) Actually open 57-203138 (JP, U) Actual-open Sho 63- 68516 (JP, U) JP-B 44-2361 (JP, B1) JP-B 54-8813 (JP, B2) JP-B 52-49540 (JP, B2) JP-B 61-54502 (JP, B2) Japanese Patent Publication Sho 51-46504 (JP, B2) Actual Publication Sho 41-10676 (JP, Y1)

Claims (1)

(57) [Claims] 1. A circulation path for linear rolling of a ball in an outer cylinder composed of a cylindrical body having a plurality of concave surfaces continuously extending on the inner peripheral surface in the direction of the central axis and forming a return path of the ball. In a method for manufacturing a linear motion ball bearing, which is manufactured by inserting a ball retainer in which is formed, a first step of manufacturing an outer cylinder material made of a cylindrical body having a uniform wall thickness, And a male type having a flower-shaped cross section formed by arranging a plurality of arcs whose center points are arranged on the same radius in rotationally symmetric positions with respect to the central axis, and a crossing of the male-shaped flower shape A second process for forming a flower-shaped formed body having a length capable of arranging a plurality of the ball cages and having a uniform thickness by cold forming using a female die having a shape substantially similar to that of the surface. And a uniform thickness created in the second step A third step of cutting the outer peripheral surface of the flower-shaped molded product into a circular shape to create the outer cylinder made of a thick-walled outer cylindrical body, and the inside of the outer cylinder created in the third step. A fourth step of inserting a plurality of the ball retainers in the axial direction, and a method of manufacturing a linear motion ball bearing.