Patent Application
20070251343
1. Field of the Invention
The present invention relates to a ball screw unit with dust cleaning and turnpike fixing mechanism, more particularly, to a mechanism for dust cleaning and turnpike fixing which has a specially designed structurally simple dust scraper to clean the dust along the ball screw unit and at the same time, forcibly hold the turnpike at position.
2. Description of the Prior Art
The ball screw unit is well-known for its excellent mobility with mechanical precisement suitable for serving precision industry such as for fabrication of mounting of a finishing tool thereby trending towards miniaturization and simplification in its structure. The conventional ball screw unit is essentially composed of a ball screw and a nut proper coupled with it. Each of two ends of the nut proper is provided with a turnpike for circulating balls to roll in and out the ball screw unit. The turnpike is engaged to the nut proper with fixing means, generally fixing screws. To keep out the ingress of dust, rubbishes and trashes into the nut proper, a scraper is usually equipped at one side of the turnpike to perform cleaning work. It is therefore a conventional ball screw unit is deemed to have a complicated structure including lots of component parts resulting in increasing difficulty in fabrication, assembly and thus raising production cost.
As shown in
Meanwhile, the structure shown in
In addition, the above described structure is only aimed at fixing the turnpike 65, it has not yet considered equipping dust clearing means between two sides of the nut proper 6 and the corresponding ball screw. The entire structure is unable to work perfectly unless it is constructed more complicated.
For these defects noticeable on the prior arts, an improvement is seriously required.
The inventor of the present invention has put forth every effort for years by continuous research and experimentation attempting to find out the remedy to palliate the inherent shortcomings of the conventional techniques described above, and at last has succeeded in coming out with the present invention.
Accordingly, the present invention is to provide a ball screw unit with dust cleaning and turnpike fixing mechanism which is simply constructed to be easily assembled, furthermore, it is able to firmly hold the turnpike at position in addition to its dust clearing function.
The present invention provides a ball screw unit with dust cleaning and turnpike fixing mechanism in which a nut proper having an inner rolling spiral slot in correspondence with that of a ball screw, is coupled with the ball screw, the rolling spiral slot of the nut proper is equipped with a circulation tunnel leading to a turnpike at its end, and an annular inlaid slot is formed at the place facing to the port of the turn pike of the nut proper. A fixed scraper formed of a C shaped annular packing is covered with a resilient soft covering layer. The width between two sides of the soft covering layer is broader than that of the annular inlaid slot, and the inner fringe of the soft covering layer is formed in to a continuous spiral scrapping tip facing against the rolling spiral slot of the ball screw.
The fixed scraper is engaged within the annular inlaid slot with its one side forcibly in contact with the turnpike, and the upper portion of the scrapping tip is formed into a continuous two-faced arcuate scrapping edge facing against the spiral wall and the crest of the ball screw.
The drawings disclose illustrative embodiments of the present invention which serve to exemplify the various advantages and objects hereof, and are as follows:
Referring to
Now the novelty of the present invention will be described in detail with reference to
The aforesaid annular fixed scraper 3, which being formed of a C shape annular packing 31, is enclosed by a resilient soft covering layer 34 around the annular packing 31. the soft covering 34 is made of rubber or plastic with a width slightly larger than that of the annular inlaid slot 12 such that the scraper 3 is able to be forcibly imposed on the annular inlaid slot 12 after being installed, and forcibly impose on the side surface of the turnpike 2 with its sides as well thereby stably holding the turnpike 2 at position.
Again referring to
As shown in
Referring to
Referring again to
As the nut proper 1 is coupled with the ball screw, the afore the spiral scrapping tip 35 and the arcuate scrapping edge 36 formed on the soft covering layer 34 is appropriately in contact with the root, side wall and the crest of the rolling spiral slot of the ball screw so as to wipe away the dust, dregs, rabbishes and trashes sticking on the rolling spiral slot.
It emerges from the above description that the present invention is more advantageous compared with the prior arts, namely:
1. Using a resilient soft covering layer to cover onto the C shaped annular packing substantially helps hold the scraper and the turnpike at position without turning or slipping.
2. The scraper has two-fold mission of stably fixing the mechanical structure and cleaning moving track of the ball screw unit. No extra dust cleaning means is needed that contribute to shorten the length of nut proper and minimize the size of entire ball screw unit.
3. The two-fold mission of the scraper effectively save needs of extra component parts and simplify the mechanical structure.
4. More leniency in dimensional allowance due to use of the soft covering layer on the scraper facilitates the fabrication and assembly work leading to curtailing the production cost.
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.
