Patent Application
20080022797
The drawings disclose an illustrative embodiment of the present invention, which serves to exemplify the various advantages and objects hereof, and are as follows:
Referring to
The bolt 1 provided with male screw threads 11 along its outer surface, wherein the male screw threads 11 are not extended to stepped portions at two sides of the bolt 1.
The nut 2 provided with a flange 20 and female screw threads 201 formed along its inner surface to mate the male screw threads 11 of the bolt 1. At least a pair of cavities 21, 22 is formed in he nut 2 to be equipped with the ball deflect units 4, 5 in each cavities 21, 22, respectively. Of the two cavities 21 and 22, the cavity 21 extends along the axial direction of the bolt 1 and is provided at the side of the flange 20 formed at one end of the nut 2, and the other one cavity 22 is formed on the surface of the nut 2 and radially extended inwardly, which is formed at the other end of the nut 2 where no flange 20 exists. As shown in
The circulation balls 3 roll and slide in the confined region between the male screw threads 11 of the bolt 1 and the female screw threads 201 of the nut 2. A spacer ring (not shown) may be interposed between the adjacent balls 3 so as to prevent their mutual collision.
The pair of circulation ball deflect units 4 and 5 from which the circulation balls 5 are fed has the ball deflect unit 4 installed at and fixed to the axial cavity 21 in the nut 2, and the ball deflect unit 5 installed at and fixed to the radial cavity 22 in the nut 2. As a whole, the radial ball deflect unit 5 has at least a spherical surface whose radius of curvature is equal to or less than the outer diameter of the nut 2, and each of the ball deflect units 4 and 5 consists of at least one components.
Referring to
1. Setting the axial ball deflect unit 4 in position on the male screw thread 11, and then moving the nut 2 towards the ball deflect unit 4 until the latter is perfectly settled in position in the cavity 21 of the nut 2 (see
2. Feeding the circulation balls 3 into the nut 2 from the radial cavity 22 until the defined number of balls 3 has spread along the helical track formed between the bolt 1 and the nut 2 (see
3. Inserting the radial ball deflect unit 5 into the radial cavity 22 formed on the nut 2 until the radial cavity 22 is completely closed (see
4. Finsihing the assembly of a ball screw unit with dual ball deflect arrangements without need of buck toothed end structure for the helical track (see
After having finished reading over the above detailed description of the present invention, one may clearly understand that the present invention has several features, which are distinctly superior to any other conventional techniques, and are as follows:
1. Well cooperation among the sizes of component parts of ball screw unit to develop the idea of employing dual ball deflect arrangements in axial and radial direction is novel and dexterous never has been thought of in this technical field prior to the present invention.
2. The dual ball deflect arrangements realized elimination of buck toothed terminal necessary for the helical track in the prior arts resulting in curtailing the production cost of the ball screw unit.
3. The interference to the nut flange by the cavity for installing the ball deflect unit is effectively overcome so that it is not necessary to lengthen the bolt to compensate reduction of number of turns for circulation balls.
4. The axial circulation tunnel formed in the nut need not to run through the whole length of nut thereby facilitating the fabrication process and reducing the dust deposition in the circulation tunnel.
5. The dual deflect arrangements contribute to effectively reducing the fabrication cost and upraising the productivity.
Many changes and modifications in the above described embodiment of the invention can, of course, be carried out without departing from the scope thereof. Accordingly, to promote the progress in science and the useful arts, the invention is disclosed and is intended to be limited only by the scope of the appended claims.
