JPH0328617B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a ball nut for a ball screw that is widely used in general industrial machinery and the like when conversion between linear motion and rotational motion is required.

Prior art and its problems All ball nuts in conventional ball screws have a cylindrical shape that surrounds the male threaded shaft, so in order to attach the ball nut to the male threaded shaft, it must be done from the end of the male threaded shaft. ,and,
Conventional ball nuts do not have a retainer that prevents the balls from falling off when removed from the male threaded shaft, and therefore have the disadvantage that it is virtually impossible to remove the ball nut from the male threaded shaft.

Means and Effects for Solving the Problems This invention provides a nut body having a shape in which a part of a cylinder is cut out in the axial direction;
The nut body includes a retainer shaped to surround an outer surface and a circumferential end surface, and the nut body has a loaded ball groove on the inner surface, a non-load ball groove on the outer surface, and integrally has a ball direction changing part at both groove ends. ,
The retainer has a no-load ball groove in the nut body;
The present invention proposes a ball nut which covers a direction changing part and has a window for exposing the balls in the load ball groove and protruding parts on both sides of the window to prevent the balls from falling off.

The ball nut of this invention has a shape that looks like a part of a cylinder cut out in the axial direction, so it can be attached at any position with respect to the male threaded shaft, and it also prevents the balls from falling off. Because it has this function, it can be freely attached to and detached from a male threaded shaft.

Embodiments Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. FIGS. 1 and 2 show a front view and a side view of an embodiment of a ball nut 10 of the present invention as seen from the inside. be.

Next, FIG. 3 is a perspective view of the nut body 20 inside the ball nut 10 of FIGS. 1 and 2. As shown in FIG. The nut body 20 basically has a shape in which a part of a cylinder is cut out in the axial direction. In the figure, reference numeral 21 indicates a load ball groove (thread groove) provided on the inner surface side of the nut body 20;
is the no-load ball (return) provided on the outside surface.
The groove, reference numeral 23, is a direction changing part for changing the direction of the ball by 180 degrees between the two grooves, and in this case, it is a rib with a substantially semicircular cross section.

Next, the retainer 30 covering the outer surface of the ball nut 10 shown in FIGS. 1 and 2 will be explained.
Since the load ball at 1 must naturally be exposed to the thread groove of the externally threaded shaft, a window for this purpose is designated by the reference numeral 31. And code 3
Reference numerals 2 and 32' are protruding portions provided on both sides of the window to prevent the ball from falling off.

The no-load ball groove 22 of the nut main body 20 is
It will be covered by the back portion 33 of the retainer 30. The direction changing portion 23 is covered by a substantially semicircular convex portion 34.

The claw-like portions 35 of the retainer act as guides for the balls 40 when they transition from the loaded ball groove 21 to the direction changing section 23 or vice versa.

The nut body 20 shown in FIG.
0, and insert the ball 40 through a ball insertion hole (not shown) provided on the back surface of the retainer.

A cover 50 shown in FIG. 4 is a cover attached to the back surface portion 33 of the retainer, and has a disc-shaped projection 51 fitted into the ball insertion hole to prevent the balls 40 from escaping. In addition, part number 52 is a screw hole for attachment.

The contact relationship of the balls 40 with the thread groove when the ball nut 10 of the present invention is attached to the male threaded shaft 60 and the protruding portions 32, 32' of the retainer 30
The positional relationship is shown in FIG. That is, in this case, the shape of the thread groove is a so-called rough arc groove.

FIG. 6 shows one example of actual use of the ball nut 10 of the present invention. The male threaded shaft 60 is supported at both ends by bearings, and is intended to convert this rotational motion into linear motion of an arbitrary object 70. The ball nut 10 in this case has a flange 11 at its end,
This flange is attached to the bottom part of the object 70 by the bolt 12.
Fix it with. In this usage example, the rotational movement of the male threaded shaft 60 provides linear movement of the object 70, just like a conventional ball nut. Since the ball nut 10 of the present invention can be freely attached to and removed from the male threaded shaft 60, the object 70 can be attached to the male threaded shaft 60 with the ball nut 10 attached as necessary.
If necessary, the object 70 can be tilted away from the male threaded shaft 60 and the object placed on a table (not shown) attached to the object 70 can be ejected at a predetermined position. This also allows for many different usage examples.

In the illustrated embodiment, the ball nut occupies one-third of the circumference and comes into contact with four rows of thread grooves, but it goes without saying that this is merely an example. . In addition, when the male threaded shaft is located in the vertical direction, the ball nut of the present invention is
It is also possible to construct a conventional ball screw by using more than one ball nut at the same time, and in that case, the structure is such that the ball nut can be removed in the radial direction. Note that the material of the retainer can be steel, plastic, etc.

7 to 9 show still another embodiment of the present invention.

FIG. 7 shows that the claw-like portions 35 in the retainer are not necessarily necessary, and the other configurations are the same as those in FIG. 1.

FIGS. 8 and 9 show modifications of the thread groove of the male threaded shaft and the protruding portion of the retainer. These embodiments are suitable for cases where the load is biased in one direction.

In FIG. 8, the right protruding portion 32' is elongated and is positioned within a groove 61 provided in the male threaded shaft 60. The proportion of the ball 40 covered by the right thread groove is reduced by the groove 61. Therefore, the load is mainly supported by the left side of the ball.

The one shown in FIG. 9 is different from the one shown in FIG. 8 in that a sloped portion 61' is provided. This slope makes it less likely that the protruding portion 32' will come into contact with the male threaded shaft 60.

Effects of the Invention According to the present invention, with the above-described configuration, the ball nut and the male threaded shaft can be freely attached and detached, and the balls will not fall off even if the ball nut is removed from the male threaded shaft. The relationship becomes extremely flexible, and the fields of application of the ball screw mechanism can be further expanded.

Since the protruding portions for preventing the balls from falling off are provided on both sides of the window, there is an effect of preventing the retainer from coming into contact with the male threaded shaft when the ball nut is fitted to the male threaded shaft.

[Brief explanation of drawings]

Figures 1 and 2 show the first ball nut of the present invention.
A front view and a side view of the embodiment shown in the figure, Figure 3 is a perspective view of only the nut body, Figure 4 is a perspective view of the mounting cover, and Figure 5 is the positional relationship with the thread groove when the ball nut is attached to the male threaded shaft. FIG. 6 is a longitudinal sectional view showing an example of the use of the ball nut of the present invention. 7 to 9 show other embodiments, with FIG. 7 corresponding to FIG. 1, and FIGS. 8 and 9 corresponding to FIG. 5, respectively. 10... Ball nut, 20... Nut body,
21... Load ball groove, 22... No-load ball groove, 23... Direction changing part, 30... Retainer, 3
1...Window, 32, 32'...Protruding part.

Claims (1)

[Claims] 1 Consists of a nut body shaped like a part of a cylinder cut out in the axial direction and a retainer shaped to surround the inner and outer surfaces and circumferential end faces of the nut body, and the nut body has a load ball groove on the inner surface and a blank groove on the outer surface. The retainer has a loaded ball groove and integrally includes ball direction changing parts at both ends of the groove, and the retainer covers the non-load ball groove and the direction changing part of the nut body and exposes the balls in the loaded ball groove. What is claimed is: 1. A ball nut comprising: a window; and protruding portions on both sides of the window to prevent balls from falling off.