Ball Screw with an Engaging Type Circulation Cassette

Abstract

A ball screw with an engaging type circulation cassette comprises a nut, a screw shaft and a circulation cassette. The nut and the circulation cassette are defined with a locking groove and a protruding block respectively, and an elastic connecting portion is defined on the circulation cassette for connecting with the engaging groove or the engaging block. Thereby this invention solves the conventional problem of fixing the circulation cassette to the nut only by using the locking element, and the elastic connecting portion of the circulation cassette can increase the convenience for assembling. Furthermore, the circulation path of the circulation cassette is of close type, which can prevent the ball from impacting the nut, so as to reduce the generation of noise.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a conventional cassette circulation type ball screw;

FIG. 2 shows another conventional cassette circulation type ball screw;

FIG. 3 is a perspective view of a circulation cassette in accordance with the present invention;

FIG. 4 is an exploded view of a cassette circulation type ball screw in accordance with an embodiment of the present invention (the screw shaft is not shown);

FIG. 5 is an assembly view of a cassette circulation type ball screw in accordance with an embodiment of the present invention (the screw shaft is not shown);

FIG. 6 is an exploded view of a cassette circulation type ball screw in accordance with another embodiment of the present invention (the screw shaft is not shown); and

FIG. 7 is an assembly view of a cassette circulation type ball screw in accordance with another embodiment of the present invention (the screw shaft is not shown).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 3-5, a ball screw with an engaging type circulation cassette in accordance with the present invention comprises: a nut 20, a screw shaft (not shown), a circulation cassette 30, and a plurality of balls (not shown).

The nut 20 is defined with an axial through hole 21, lateral circulation holes (not shown), and a helical groove 22. A recess 23 is formed in the end surface of the nut 20 and is located correspondingly to the helical groove 22 and the circulation holes, and an annular locking groove 24 is formed outside the recess 23.

The screw shaft is inserted in the through hole 21 of the nut 20, and the screw shaft cooperates with the helical groove 22 of the nut 20 to define a space for reception of the plurality of balls.

The circulation cassette 30 is received in the recess 23 of the nut 20 and is defined with a close type circulation path 31. A laminal guiding piece 311 is arranged in the circulation path 31 for abutting against the helical groove 22 of the nut 20, and the circulation path 31 is connected to the circulation holes. A plurality of protruding elastic connecting portions 32 is formed on the circulation cassette 30, and a plurality of protruding blocks 33 is integrally connected to the end of the connecting portions 32 and is shaped for mating with the locking groove 24. A slant surface 331 is formed on each of the protruding blocks 33 and is located in the direction of the locking groove 24, and an abutting surface 332 is formed on each of the protruding blocks 33 and located opposite the slant surface 332.

The protruding block 33 of the circulation cassette 30 and the locking groove 24 of the nut 20 can be interchanged in position according to needs. The locking groove 24 can also be formed in the elastic connecting portions 32 of the circulation cassette 30.

In assembly, the screw shaft is inserted in the nut 20 initially, forming a ball receiving space with respect to the helical groove 22 of the nut 20. At this moment, the circulation cassette 30 can be placed directly into the recess 23 of the nut 20 and is positioned therein via the end surface of the nut 20. At this moment, with the aid of the slant surface 331 and the elastic connecting portions 32 will be deformed to enable the protruding blocks 33 of the circulation cassette 30 to enter the locking groove 24 and to be locked therein. Besides, the protruding blocks 33 of the circulation cassette 30 is engaged in the locking groove 24 since it is restricted by the abutting surface 332, thus positioning the circulation cassette 30 on the end surface of the nut 20.

By such arrangements, with the help of the slant surface 331 and the deformation of the elastic connecting portion 32, the protruding blocks 33 of the circulation cassette 30 can be directly engaged and positioned in the locking groove 24 of the nut 20 very quickly, without needing any locking elements.

On the other hand, the circulation cassette 30 is defined with the close type circulation path 31, the laminal guiding piece 311 is arranged in the circulation path 31 for abutting against the helical groove 22 of the nut 20, and the circulation path 31 is connected to the circulation holes. And the guiding piece 311 is located between the balls and the nut 20. Therefore, the balls entering the circulation cassette will not impact the metal nut, and the noise will be reduced.

Referring to FIGS. 6 and 7, another embodiment of the locking grooves is shown, wherein the locking grooves 24 of the nut 20 are not annular and are shaped for mating with the protruding blocks 33 of the elastic connecting portion 32.

While we have shown and described various embodiments in accordance with the present invention, it is clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.

Claims

1. A ball screw with an engaging type circulation cassette comprising a nut having circulation holes, a screw shaft inserted in the nut, and a circulation cassette, characterized in that: the circulation cassette is defined with elastic connecting portions, at least one protruding block is formed on the elastic connecting portion for engaging with at least one locking groove in the nut.

2. The ball screw with an engaging type circulation cassette as claimed in claim 1, wherein the circulation cassette is defined with a close type circulation-path, a laminal guiding piece is arranged in the circulation path for abutting against the helical groove of the nut, and the circulation path is connected to the circulation holes.

3. The ball screw with an engaging type circulation cassette as claimed in claim 1, wherein: a recess is formed in an end surface of the nut for abutting against a helical groove and circulation holes of the nut, a locking groove is formed in the recess; andthe circulation cassette is engaged in the recess of the nut, the elastic connecting portions are protruded out of the circulation cassette, a slant surface is formed on the protruding block and is located in the direction of the locking groove, and an abutting surface is formed on the protruding block and located opposite the slant surface.

4. The ball screw with an engaging type circulation cassette as claimed in claim 2, wherein: a recess is formed in an end surface of the nut and is located correspondingly to a helical groove and circulation holes of the nut, a locking groove is formed in the recess; andthe circulation cassette is engaged in the recess of the nut, a plurality of protruding elastic connecting portions is formed on the circulation cassette, a slant surface is formed on the protruding block and is located in the direction of the locking groove, and an abutting surface is formed on the protruding block and located opposite the slant surface.

5. The ball screw with an engaging type circulation cassette as claimed in claim 3, wherein the locking groove is annular and is located outside the recess.

6. The ball screw with an engaging type circulation cassette as claimed in claim 4, wherein the locking groove is annular and is located outside the recess.

7. The ball screw with an engaging type circulation cassette as claimed in claim 1, wherein: a recess is formed in an end surface of the nut and is located correspondingly to the helical groove and the circulation holes, the protruding block is formed outside the recess, a slant surface is formed on the protruding block, and an abutting surface is formed on the protruding block and located opposite the slant surface; andthe circulation cassette is engaged in the recess of the nut, a plurality of protruding elastic connecting portions is formed on the circulation cassette, the locking groove is formed in the elastic connecting portion and is shaped for mating the protruding block, the protruding block is engaged in the locking groove.

8. The ball screw with an engaging type circulation cassette as claimed in claim 2, wherein: a recess is formed in an end surface of the nut and is located correspondingly to the helical groove and the circulation holes, the protruding block is formed outside the recess, a slant surface is formed on the protruding block, and an abutting surface is formed on the protruding block and located opposite the slant surface; andthe circulation cassette is engaged in the recess of the nut, a plurality of protruding elastic connecting portions is formed on the circulation cassette, the locking groove is formed in the elastic connecting portion and is shaped for mating the protruding block, the protruding block is engaged in the locking groove.