JP2002089650A - Ball bearing screw and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball bearing screw and its manufacturing method whereby the ball bearing screw can be manufactured at a low cost. SOLUTION: The ball bearing screw is composed of a screw shaft provided at the surface with a first spiral groove and a nut body provided at the inside with a second spiral groove to be fitted on the screw shaft. In the second spiral groove, a return hole is formed, with which a return guide component 7 is coupled. The middle part of the return guide component 7 is shaped in a groove, and a hollow circular pipe part 74 is formed at each end. At each side of the middle part of the component 7, a wing-shaped extension part 71 is formed, in which a mounting hole 72 is formed to admit insertion of a bolt, and the component 7 is connected with the nut body. A semicircular scooping tongue part 75 is formed at each end of the guide component. Because the guide component is manufactured from sheet metal, the manufacturing costs remain low.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a ball bearing screw and a method for manufacturing the same.

[0002]

2. Description of the Related Art As shown in FIG. 7, a ball bearing screw generally seen mainly includes a screw shaft 1, a nut body 2, a ball 3, a return tube 4,
A pusher 5 and a screw bolt 6 are provided. A spiral groove 11 for rotating a ball is provided on the surface of the screw shaft 1. The nut main body 2 is formed in a hollow shape, is fitted to the outer part of the screw shaft 1, and has a spiral groove corresponding to the spiral groove 11 of the screw shaft 1 installed in the inner part. The nut body 2 has a flange 21 and a mounting hole 22 for mounting the nut body 2 to a mechanical device at an upper portion. Also, there is a flat surface 2 on the upper part of the nut body.
3 are formed, and a return hole 24
a, return hole 24b and plural screw bolt holes 2
5 are formed. The U-shaped return tube 4 is inserted into the return hole 24a and the return hole 24b.
3 and is fixed by the pusher 5 and the screw bolt 6. The plurality of balls 3 move between the nut main body 2 and the screw shaft 1 via the return tube 4. A scoop-up tongue is formed on the return tube so that the ball does not jump out of the return tube when moving from the spiral groove into the return tube.
The scooping tongue has sufficient strength. A return passage for the ball is formed, and a presser is installed to fix the return tube on the nut body. The return tube is formed in a groove shape to have a ball return passage, and need not be formed in a tubular shape. Also, when the return channel is formed in the nut body, the return tube is formed in a lid shape, so that the return tube of the ball bearing screw does not need to be tubular.

[0003]

A conventional ball bearing screw is formed by cutting a hollow circular tube, forming a curved U-shape, and manufacturing a return tube. If no special treatment is performed during the bending process, the hollow circular tube deforms and contracts after the bending, making it impossible for the ball to pass. Therefore,
After the hollow circular tube is curved and formed into a U-shape, both ends are cut off by a machine, an interference portion between the hollow circular tube and the spiral groove 11 of the screw shaft 1 is removed, and an arc-shaped scooping tongue portion 4 is formed.
1 is formed. For this reason, the manufacturing cost is extremely high.

Accordingly, an object of the present invention is to provide a ball bearing screw which can be manufactured at low cost and a method for manufacturing the same.

[0005]

According to the ball bearing screw of the first, second or third aspect of the present invention, a screw shaft having a first helical groove having a semicircular cross section is formed on the surface, and a second helical groove is formed on the inner portion. A second spiral groove corresponding to one spiral groove is formed, and a nut main body is fitted to an outer portion of the screw shaft. A return hole is formed in the second spiral groove, and a return guide component is connected to the return hole. An intermediate portion of the return guide component is formed in an open groove shape, and both end portions are formed in a hollow tubular shape. A plurality of balls are held in the first spiral groove and the second spiral groove. The return guide part has wing-like extensions formed on both sides of the groove-shaped intermediate part, a hole is formed in the wing-like extension, a screw bolt is inserted into the hole, and the return guide part is connected to the nut body. Further, the return guide part has a semicircular scooping tongue formed at both ends.

According to the method for manufacturing a ball bearing screw according to claim 4 or 5, of the present invention, the return guide component is formed by cutting a sheet metal into a predetermined shape by a press method, and then forming an intermediate portion into a groove shape by a press method. The longitudinal section of both ends is formed into a J-shaped part, and the J-shaped part is curved to form a hollow circular tube. A mandrel is used to assist when the J-shape is curved to form a hollow tube.

[0007] Since the return guide component is manufactured from sheet metal, it can be manufactured at low manufacturing cost. Furthermore, since the sheet metal part is manufactured using a mold, the stability of the product is excellent. In addition, deformation and shrinkage of the curved portion after the hollow circular tube is curved is not generated. Since the slot structure of the return guide component is directly connected to the nut body, and the wing-like extension and the slot structure are integrally molded, the volume occupied by the wing-like extension and the slot structure is significantly reduced, and the volume of the composition component can be reduced.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the return guide part 7 of the ball bearing screw according to one embodiment of the present invention has a slot structure 73 formed at an intermediate portion, and is connected to a return tube and a presser of a conventional ball bearing screw. On both sides of the slot structure of the return guide component 7, wing-like extensions 71 are formed, and mounting holes 72 are formed in the wing-like extensions 71, and the wing-like extensions 71 and the mounting holes 72 are used for a conventional ball bearing screw presser. Play a role. The screw bolt 6 is attached to the mounting hole 7 of the wing extension 71.
2, the return guide part 7 is fixed to the screw bolt hole 25. The return guide component 7 is attached to the nut body 2 and the return guide component 7
Is connected to the nut body 2 to form a return passage having the same function as the return tube 4.

As shown in FIG. 1, a return guide component 7 according to an embodiment of the present invention has hollow tube portions 74 formed at both ends. A semi-arc scooping tongue 75 is formed at the end of the circular tube 74. The return guide component 7 and the nut body are connected, the circular tube portion 74 is inserted into the return hole of the nut body, and the scooping tongue portion 75 is installed close to the spiral groove of the screw shaft.

The ball in the spiral groove moves inside the return guide part 7, and the ball inside the return guide part 7 moves to a predetermined position in the spiral groove. A chamfer 76 is formed at a position where the circular tube portion 74 and the slot-like structure 73 are connected so that the ball can easily move inside the return guide component 7.
As shown in FIG. 2, since the chamfer 76 is formed, the ball can easily move between the circular tube portion 74 and the slot-like structure 73.

In the ball bearing screw according to one embodiment of the present invention, the return guide part 7 is formed by pressing a sheet metal. As shown in FIG. 3, in the sheet metal press manufacturing of the return guide part 7, the scooping tongue 75 and the wing-like extension 7
1 is formed. The pressing process is repeated once to several times, and the return guide component 7 is formed from the sheet metal.

As shown in FIGS. 4 and 5, a wing-like extension 71, a mounting hole 72, a slot-like structure 73, a scoop-up tongue 75 and the like are molded, and a circular tube 74 has a J-shaped cross section. . As shown in FIG.
Is curved and formed into a semicircular shape, and is combined with the arc portion 741 to form a circular shape. J-shaped slender pipe part 7
42 is curved and formed in a semicircular shape, and the arc portion 741 is formed.
When formed into a hollow circular tube, the size after formation is stable if assisted by a mandrel.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a return guide part of a ball bearing screw according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line CC of FIG.

FIG. 3 is a schematic view showing a method of manufacturing a return guide component of a ball bearing screw according to one embodiment of the present invention.

FIG. 4 is a perspective view showing a return guide part of the ball bearing screw according to one embodiment of the present invention.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6 is a sectional view taken along line BB of FIG. 5;

FIG. 7 is an exploded perspective view showing a conventional ball bearing screw.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 screw shaft 2 nut body 3 ball 4 return tube 5 presser 6 screw bolt 7 return guide part 11 spiral groove 21 flange 22 mounting hole 23 plane 24a return hole 24b return hole 25 screw bolt hole 41 scooping tongue 51 mounting hole 71 wing shape Extension 72 Mounting hole 73 Slot-like structure 74 Circular tube 75 Scoop-up tongue 76 Chamfer 741 Arc 742 Pipe

Claims (5)

[Claims] 1. A screw shaft having a surface on which a first spiral groove having a semicircular cross section is formed, and a second spiral groove corresponding to the first spiral groove is formed on an inner portion, and an outer portion of the screw shaft is formed. A pair of return holes are formed in the second spiral groove,
A return guide component formed of sheet metal is connected to the return hole, an intermediate portion of the return guide component is formed in an open groove shape, both ends are formed in a hollow cylindrical shape, and a plurality of balls are formed. A ball bearing screw held in the first spiral groove and the second spiral groove. 2. The return guide component has wing-like extensions formed on both sides of an intermediate portion, and the wing-like extension has a hole into which a screw bolt is inserted, and the return guide component is connected to the nut body. The ball bearing screw according to claim 1, wherein the screw is formed. 3. The ball bearing screw according to claim 1, wherein the return guide part has a semicircular scooping tongue formed at both ends. 4. A method of manufacturing a return guide part of a ball bearing screw, comprising: a step of cutting a sheet metal into a predetermined shape by a press method; and forming a groove-like portion near a central portion of the sheet metal; A return guide part for a ball bearing screw, comprising: a step of forming a vertical cross section to have a J-shape; and a step of bending the J-shaped end portions to form a hollow circular tube. Manufacturing method. 5. The method according to claim 4, wherein a single mandrel is used as an auxiliary in the step of bending both end portions into a hollow cylindrical shape. .