Abstract:
A ball circulation system for linear guide way includes a slide rail, a slider coupled with the slide rail, and two end covers of the slider with an oil scraper. A cross-wise circulation passage and a separated circulation passage respectively formed at two side of the end cover are integrally combined in one structure so as to form two independent and opposite ball circulations. By so space in the circulation system is able to accommodate more rolling balls by twice filling procedure thereby improving the efficiency of assembly work. Besides, up and down motion of the rolling balls during circulation causes a uniform lubrication effect. Allowing accommodation of more rolling balls means substantially improving load carrying ability of the linear guide way.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a ball circulation system for linear guide way, and more particularly to a ball circulation system in which the cross-wise and the separated turnoff paths are provided integrally or separately in the end covers of the slider for rolling balls to turn away for circulation. 
   2. Description of the Prior Art 
   A load transportation mechanism, linear guide way, is composed of a slide rail, a slider and its end covers to slide along the slide rail, an oil scraper affixed to the end cover, and a plurality of rolling balls interposed among the slide rail, the slider, and its end covers to make continuous circulation therefore a load entrained table is transported by the slider linearly moving along the slide rail with a high mechanical precisions. 
   The turn-off paths for rolling balls to circulate in a conventional linear guide way are generally divided into independently separated (for balls) and cross-wise (for rollers) types as shown in  FIG. 1  (separated) and  FIG. 2  (cross-wise) respectively. However, both types need to establish four independent circulation paths which being disadvantageous and in convenient for fabrication and practical application, namely: 
   1. Assembly procedure is time consuming because there are four circulation paths to install rolling balls for each mechanism. 
   2. Owing to the gravity, the balls in the upper circulation paths usually get more lubricant than those in the lower ones causing an uneven lubrication effect. 
   3. A non uniform distribution of load occurs between the upper and lower circulation paths. 
   It is what the reason the inventor has put forth every effort for years by continuous research and experimentation trying to discover the remedy to palliate the inherent shortcomings of the conventional techniques described above, and at last succeeded in realizing the present invention. 
   SUMMARY OF THE INVENTION 
   Accordingly, the present invention is to provide a ball circulation system for linear guide way in which the cross-wise and the independent turn-off paths are provided integrally or separately in the end covers of the slider forming two independent and counter-directional circulations. 
   Another, the present invention is to construct a simple oil passage in the end covers so as to effectively lubricate the rolling balls. 
   The slider&#39;s end cover is composed of a main block, a cover plate, and an outer cap, an upper turn-off path and a lower turn-off path are provided respectively on two sides of the end cover, while the other side thereof is provided with a tilted turn-off path and a U-shaped turn-off path. With this structure, a combined cross-wise and separated circulation system is integrally formed. Moreover, corresponding upper, lower, and tilted turn-off ports are aligned to the upper, lower, and tilted turnoff path respectively. In the main block of the end cover, oil paths in connection with the upper and tilted turn-off paths are formed, and orifices are opened on the main block for the oil paths to lubricate both the upper and tilted turnoff paths and the upper and tilted turn-off ports. When the two identically constructed end covers are fitted to each end of the slider respectively, the turnoff paths of the two end covers are counter positioned. With this arrangement, when the ball starts moving form one of the two end covers along the upper turnoff path to the opposite end cover, then it flows to the lower turn-off path by way of the U-shaped turnoff path thereof, after that it continues to travel along the tilted turn-off path to return to the upper turn-off path of the end cover from where it starts after performing upward circulation. In this manner, the rolling balls continuously perform endless circulation between the slider and the slide rail. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above objects and other advantages of the present invention will become more apparent by describing in detail the preferred embodiments of the present invention with reference to the attached drawings in which: 
       FIGS. 1 and 2  are two perspective views of conventional linear guide way; 
       FIG. 3  is a perspective view of the linear guide way using a ball circulation system of the present invention; 
       FIG. 4  is an exploded illustrative view of the linear guide way using the ball circulation system of the present invention; 
       FIG. 5  is a transverse cross sectional view of the linear guide way using the ball circulation system of the present invention; 
       FIG. 6  is an exploded illustrative view of the end cover according to the present invention; 
       FIG. 7  is an cross sectional view of the end cover according to the present invention; 
       FIG. 8  is an illustrative view showing how to assemble the end cover with the linear guide way according to the present invention; and 
       FIG. 9 to 12  are from first to four embodiments in order according to the present invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring  FIG. 3  through  FIG. 5 , the linear guide way using the ball circulation system of the present invention is composed of a slide rail  1 , a slider  2  sliding along the slide rail  1 , two end covers  3  for the slider  2 , two oil scraper  4  attached to the end covers  3 , and a plurality of rolling balls  5 . An upper and lower circulation spaces (no numeral symbol, refer to  FIG. 5 ) along both sides of the linear guide way are left for rolling balls to make an endless circulation. 
   Referring to  FIG. 6 , the exploded view of the end cover, the kernel of the present invention lies in that the end cover  3  is composed of a main block  31 , a cover plate  32 , and an outer cap  33 . 
   An upper turn-off path  311  and a lower turn-off  312  path are separately provided at one side of the main block  31 , while the other side thereof are provided with a tilted turn-off path  313 , and a U-shaped turn-off path  314  facing cross-wise to the path  313 , and a vacancy is remained at the rear side of the U-shaped turn-off path  314  facing to an oil scraper  4  for the convenience of filling rolling balls. Besides, an oil path  315  in connection with the upper and tilted turn-off paths  311  and  313  is provided on the surface of the main block  31  facing to the slider  2 , and the oil path  315  is provided with an orifice  316  for infusing lubrication oil to the upper and tilted turn-off paths  311  and  313 . 
   An upper turning port  321 , and a lower turning port  322  separated with each are provided at one side of the cover plate  32  facing respectively to the upper and lower turn-off paths  311  and  312 , and a tilted turning port  323  is facing to the tilted turn-off path  313 . 
   The outer cap  33  is for closing the rear side of the vacancy of the U-shaped turn-off path  314 , and another tilted turning port  331  is formed facing to the U-shaped turn-off path  314  of the main block  31 . 
   Referring to  FIG. 7 , in this cross sectional view of the end cover, it shows how the end cover  3  including its main block  31 , cover plate  32 , and outer cap  33  is assembled with the linear guide way. At first two similar cover plates  32  are respectively attached to two ends of the slider  2 , and then two similar main block  31  are covered by respective cover plates  32  by aligning their upper, lower, and tilted turn-off paths  311 ,  312  and  313  to the upper, lower, and tilted turning ports  321 ,  322 , and  323  of the cover plates  32  respectively. At this time two front ends of the U-shaped path  314  of each main block  31  is just facing to the lower rolling space (see  FIGS. 5 ,  6  and  8 ) when an upper rolling path  21  of the slider  2  and the slide rail  1  are coupled with the slider  2 , and two sides of each coupled cover plate  32  with the main block  31  are formed into cross-wise and separated turning direction. Then by mating the cross-wise tuning position of one cover plate  32  and the main block  31  with the separated turning position of the other cover plate  32  and the main block  31 , and by mating the separated turning position of the former with the cross-wise turning position of the latter, an integrated cross-wise and separated circulation vacancy can be obtained at both sides of the linear guide way. In the last step, fixedly close the rear side of vacancy formed at the place the outer cap  33  facing to the U-shaped turn-off path  314  of the main block  31  after filling the rolling balls  5  into the linear guide way from the vacancy thereby completing the assembly of the end cover  3 . 
   Referring to  FIG. 8 , this drawing illustrate how to assemble the end cover  3  with the linear guide way. After the upper, lower, and tilted turn-off paths  311 ,  312 , and  313  formed at both sides of the main block  31  are respectively mated with the separated upper and lower turning ports  321 ,  322 , and the tilted turning port  323  formed on the cover plate  32 , and closing the U-shaped turn-off path  314  of the main block  31  with the outer cap  33 , both the cross-wise and separated turning circulation passages will be provided at two sides of the end cover  3 . In this manner, after the two similarly constructed end covers  3  are respectively fitted to two ends of the slider  2 , the turning circulation passage of the two end covers  3  will be located at opposite positions. 
   With this construction, when the ball  5  starts traveling from one end cover  3  to the other via upper turn-off path  311 , it makes a downwards turning by way of the U-shaped turn-off path  314  of the latter end cover  3  and reaches the lower turn-off path  312  of the former end cover  3 . Then continues to travel along the tilted turn-off path  313  of the latter end cover  3  thereby making an upwards turning and returns to the upper turn-off path  311  of the former end cover  3 . Such an endless circulation of the ball  5  between the slide rail  1  and the slider  2  will be maintained as long as the linear guide way operates. 
   It emerges from the above description that the ball circulation system for linear guide way according to the present invention in which the cross-wise and separated circulation passages are integrally combined together by the end covers  3  is apparently more advantageous than one in which the two circulation passages are segregated as in the conventional techniques in several respects, namely: 
   1. The two independent circulations combined in one piece only needs twice operations to fill the rolling balls resulting in facilitating assembly work. 
   2. Rolling balls  5  are able to make up and down circulation and uniformly lubricated with a simply constructed oil circulation path. 
   3. Up and down circulation of rolling balls  5  causes reducing their load stress, the lengthened circulation passage allows to accommodate more rolling balls  5  in the linear guide way further contributes to reducing their loading stress. 
   In addition, for further variation of design aspect for the end cover structure, some of the extra design features are added for the end cover  3 . 
   In a first embodiment shown in  FIG. 9 , the oil path  315  formed on the main block  31  is replaced by an oil path  324  formed on the cover plate  32 . The oil path  324  is in connection with the upper and tilted turning ports  321  and  323  so as to introduce the externally supplied oil into the oil path  324  from the orifice  316  of the main block  316  thereby lubricating the rolling balls  5  via upper and tilted turning posts  321  and  323 . 
   In a second embodiment shown in  FIG. 10 , alternatively, the upper, lower, and tilted turning ports  321 ,  322 , and  323  are assembled with the cover plate  32  after separately formed into independent structure instead of integrally formed at the beginning as that described above. 
   In a third embodiment shown in  FIG. 11 , the vacancy  317  is provided on the main block at the rear position opposite of the oil scraper  4  for the upper or lower turn-off paths  311 ,  312 , and a turning port  322  facing to the vacancy  317  is formed on the outer cap  33 , and the turning port  332  and the tilted port  331  are engaged in one piece with a connecting arm  333 . 
   In a fourth embodiment shown in  FIG. 12 , the vacancy  317  and the turning port are formed in similar way as the third embodiment, the only difference is that the two turning ports  331  and  332  are separately formed. 
   While the invention has been described in terms of what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention need not be limited to the disclosed embodiments. On the other hand, it is intended to cover various modifications and similar arrangement included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.