Abstract:
The present invention relates to a ball spacer and the rolling device using it. The ball spacer of the present invention makes the ball doesn&#39;t touch to his adjoining ball, so as to reduce the noise. Besides, the ball spacer comprises a cylinder surface touching to the ball, so that the spacer can rotate according to the ball and almost hasn&#39;t relative motion to his adjoining ball.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a ball spacer and rolling device using it applied to prevent the collision between two adjacent balls, wherein the rolling device comprises ball bearing, ball screw and linear rolling guide unit, the balls includes the spheres made of varies of materials, such as steel ball, ceramic ball and so on.  
           [0003]    2. Description of the Prior Arts  
           [0004]    A rolling device with balls used is invented based on the principle that rolling friction drag is far minor than sliding friction drag. For example, ball bearing can make the parts of which rotate relative to a cylindrical surface by virtue of the roll of balls (namely the ball rotating bearing) or move linearly (namely linear ball bearing). Ball screw enables the parts of the same to relatively helical move by virtue of the roll of balls. Linear rolling guide unit enables the parts of which to linearly move along the rail by virtue of the roll of balls. FIG. 8 shows a rolling device of prior arts, in which, a moving member  1  moves relative to a fixed member  2 , balls  3  are disposed therebetween and move left counterclockwise in case of left movement of the moving member  1 . Although the moving member  1  doesn&#39;t direct contact the fixed member  2  and reduced the friction drag, there are noises and frictions between the adjacent balls  3 ,  3 ′ due to they contact directly and move reverse to each other (ball  3  rolls upward while ball  3 ′ rolls downward).  
           [0005]    [0005]FIG. 9 shows an improved design disclosed in U.S. Pat. No. 5,615,955, wherein a spacer-ball  4  having a minor diameter than that of the balls  3  is interposed between the balls  3 ,  3 ′, so that the spacer-ball  4  can rotate clockwise in case of counterclockwise rotation of the balls  3 ,  3 ′, in this case, the balls  3 ,  3 ′ don&#39;t contact each other and there is almost no relative motion between the spacer-ball  4  and the balls  3 ,  3 ′, such improve the noise and friction accordingly. However, same space of this design only accommodates half quantity of balls  3 ,  3 ′ as compared with  5  prior arts, the load capacity of which is seriously reduced.  
           [0006]    [0006]FIG. 10 shows an improved ball spacer structure which is widely used presently, the embodiments as disclosed in U.S. Pat. No. 5,597,243 in terms of the application to ball bearing, in U.S. Pat. Nos. 5,927,858, 6,095,009, 6,347,558, 6,352,367, 6,415,676, and 6,513,978 in terms of the applications to ball screw and linear rolling guide unit. In the improved ball spacer structure of this type, a spacer-block  5  is interposed between the balls  3 ,  3 ′ for preventing the adjacent balls colliding each other. Due to the balls  3 ,  3 + need to rotate while the spacer-block  5  can&#39;t, there is apparent relative motion between them. Although no direct collision exists between balls  3 ,  3 ′ and noise problem is improved, there is still friction between the balls  3 ,  3 ′ and the spacer-block  5 . In addition, there is another type of improved ball spacer structure which takes form of belt-like (or is named chain-like) (not shown), such as U.S. Pat. Nos. 5,951,168, 5,993,064, 5,988,883, 6,094,819, 6,142,671 and 6,155,718, which spacer-blocks are connected by belt, the function of which, however, is basically identical to FIG. 10 that the spacer-blocks of which can&#39;t rotate and there is apparent friction between the spacer-block and the balls.  
           [0007]    Thereby, the ball spacer and rolling device using it of prior arts is unable to improve the collision and friction between the adjacent balls on condition that the load capacity is not dramatically reduced.  
           [0008]    The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional ball spacer and rolling device using it.  
         SUMMARY OF THE INVENTION  
         [0009]    In accordance with one aspect of the present invention, there is provided with a ball spacer having axial symmetrical cylindrical surface for contacting with balls, the two adjacent balls are separated from each other and located at both sides of the ball spacer, such that the ball doesn&#39;t directly collide with the adjacent one, so as to improve the collision-caused noise between the adjacent balls.  
           [0010]    Due to the ball spacer has axial symmetrical cylindrical surface, the ball spacer will rotates reverse to the rotation of the balls, there is almost no relative motion happened on the contacting points between the balls and the ball spacer, such that to reduce the friction therebetween.  
           [0011]    For prevention of bigger interval between the adjacent balls, the ball spacer is designed as having rather minor diameter in middle section of the cylindrical surface while having greater diameters in both end sections, such to match with the contour of the balls and reduce the spaces of the ball spacer occupied, the ball spacer and rolling device using it can accommodate more balls as compared with spacer-ball of prior arts. The ball spacer is designed as having both spherical end surfaces which likes a sphere so as to prevent apparent interferences between the balls and the surface of rolling track.  
           [0012]    The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which shows, for purpose of illustrations only, the preferred embodiment in accordance with the present invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    [0013]FIG. 1 is a cross sectional view of ball spacer and the rolling device using it in accordance with the present invention;  
         [0014]    [0014]FIG. 2 is a cross sectional view taking along A-A′ of FIG. 1;  
         [0015]    [0015]FIG. 3 is an amplified view of the ball spacer and the balls in accordance with the present invention;  
         [0016]    [0016]FIG. 4 is a plan view, partly in section, of showing a ball spacer in accordance with a second preferred embodiment of the present invention;  
         [0017]    [0017]FIG. 5 shows a ball spacer of the present invention applied to a ball bearing;  
         [0018]    [0018]FIG. 6 shows a ball spacer of the present invention applied to a ball screw;  
         [0019]    [0019]FIG. 7 shows a ball spacer of the present invention applied to a linear rolling guide unit;  
         [0020]    [0020]FIG. 8 shows a first type of rolling device of prior arts;  
         [0021]    [0021]FIG. 9 shows a second type of rolling device of prior arts;  
         [0022]    [0022]FIG. 10 shows a third type of rolling device of prior arts. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]    [0023]FIG. 1 is a cross sectional view of ball spacer and the rolling device using it in accordance with the present invention, FIG. 2 is a cross sectional view taking along A-A′ of FIG. 1. Wherein a ball spacer  6  has a cylindrical surface  61  serving to separate ball  3  and ball  3 ′ apart at both sides of the ball spacer  6 , such that the balls  3 ,  3 ′ will not collide with each other. As shown clearly in FIG. 1, the ball spacer  6  rotates clockwise in case of counter-clockwise rotation of the balls  3 ,  3 ′ so that there is almost no relative motion happened on the contacting points between the balls  3 ,  3 ′ and the ball spacer  6 . Furthermore, the diameter of the middle section of the cylindrical surface  61  of the ball spacer  6  is minor than that of both ends of the same so as to match with the contours of the balls  3 ,  3 ′, such that the space the ball spacer  6  occupied is reduced and on the premise that the balls  3 ,  3 ′ don&#39;t collide with each other, the space therebetween may be much reduced as compared with that of the conventional spacer-ball. Thereby the rolling device of the present invention may accommodate more balls  3 ,  3 ′ relatively. As FIG. 2 shown that both end surfaces  62  of the ball spacer  6  are spherical surfaces which are two portions of the spherical surface of a same sphere. That is to say that the shape of the ball spacer  6  of the present invention just likes an apple which has been bitten a portion off wholly around the periphery (also likes a sandglass) and the cylindrical surface  61  is exactly the contour of the portion bitten from the apple. Due to both end surfaces  62  are two portions of the spherical surface of same sphere, the ball spacer  6  of the present invention still maintains the advantages of sphere. In case that the ball spacer  6  moves in the rolling track, there is no apparent interferences between the two end surfaces  62  of the ball spacer  6  and the surface of rolling track even if the ball spacer  6  deviates from the original designed track occasionally. Furthermore, if the two end surfaces  62  contact the balls  3 ,  3 ′ in case of large intervals between the ball spacer  6  and the adjacent balls  3 ,  3 ′, the ball spacer  6  will not be jammed but will roll as a spacer ball rolls until the cylindrical surfaces  61  of the ball spacer  6  contact the balls  3 ,  3 ′ again. In addition, the ball spacer  6  should not be larger than the section of the rolling track, in this case, it is a simple design method to make the ball spacer  6  slightly smaller than the size of the balls  3 ,  3 ′. Thus, the two end surfaces  62  of the ball spacer  6  may be designed as two portions of same sphere having a radius of curvature slightly minor than the radius of the balls  3 ,  3 ′.  
         [0024]    [0024]FIG. 3 is an amplified view of the spacer and the balls. In which, the intervals between the cylindrical surfaces  61  and the balls  3 ,  3 ′ are very small so as to diminish the space that the ball spacer  6  occupies. On the other hand, the distance between the balls  3 ,  3 ′ will be varied because of making a turn, thus the ball spacer  6  should be designed as having certain flexibility in distance for permitting some changes in the distance between the balls  3 ,  3 ′. From front view, the contour of the ball spacer  6  is in form of circular arc, the radius of the circular arc is minor than that of the balls.  
         [0025]    [0025]FIG. 4 is a plan view, partly in section, of showing a spacer in accordance with a second preferred embodiment of the present invention. Wherein each of the end surfaces  62  of the ball spacer  6  is provided with an annular groove  63  for increasing flexibility of the ball spacer  6 . In case that the end portion  611  of the cylindrical surface  61  contacts the balls, if the distance between the balls  3 ,  3 ′ changes slightly the end portion  611  will be more susceptible to bend, so as to reduce the load on the balls.  
         [0026]    [0026]FIG. 5 shows a ball spacer of the present invention applied to a ball bearing. The ball bearing includes an outer ring  71 , an inner ring  72 , a plurality of balls  3 ,  3 ′ and ball spacers  6 , wherein the outer ring  71  is provided in the inner surface with an annular rolling track (not shown) and the inner ring  72  is correspondingly provided in the outer surface with an annular rolling track (not shown), the outer ring  71  is mounted to outside of the inner ring  72 . The balls  3 ,  3 ′ are arranged between the outer ring  71  and the inner ring  72  and move therebetween in case of rotation of the outer ring  71  with respect to the inner ring  72 . The ball spacers  6  are disposed between paired adjacent balls  3 ,  3 ′ such that the balls  3 ,  3 ′ don&#39;t contact each other. In case of rotation of the balls  3 ,  3 ′, the ball spacers  6  rotate reversely to the rotating direction of the balls  3 ,  3 ′ so as to reduce to the friction drag between the ball spacer  6  and the balls  3 ,  3 ′.  
         [0027]    [0027]FIG. 6 shows a ball spacer of the present invention applied to a ball screw. The ball screw includes a nut  81 , a screw shaft  82 , a circulation assembly  82 , a plurality of balls  3 ,  3 ′ and ball spacers  6 . Wherein the nut  81  is provided in the inner surface with helical groove (not shown) and an opposite annular groove (not shown) is correspondingly provided in the outer surface of the screw shaft  82 . The balls  3 ,  3 ′ are helically arranged between the nut  81  and the screw shaft  82  along the helical grooves of the same. The circulation assembly  83  enables the balls  3 ,  3 ′ to return to front end of the helical groove from the back end. In case of rotation of the nut  81  with respect to the screw shaft  82  the balls  3 ,  3 ′ move therebetween. The ball spacers  6  are arrange  83  between adjacent paired balls  3 ,  3 ′ such that the balls don&#39;t contact each other directly. In case of rotation of the balls  3 ,  3 ′, the ball spacers  6  rotate reversely to the rotating direction of the balls  3 ,  3 ′ so as to reduce to the friction drag between the ball spacer  6  and the balls  3 ,  3 ′.  
         [0028]    [0028]FIG. 7 shows a ball spacer of the present invention applied to a linear rolling guide unit. The linear rolling guide unit includes a sliding block  91 , rail  92 , circulation unit  93 , balls  3 ,  3 ′ and ball spacers  6 . Wherein the sliding block  91  is provided in the inner surface with a rolling groove (not shown) and an opposite rolling groove (not shown) is correspondingly defined in the outer surface of the rail  92 . The sliding block  91  is mounted on the outside of the rail  92 , the balls  3 ,  3 ′ are arranged between the sliding block  91  and the rail  92  along the rolling grooves of the same. The circulation unit  93  is provided for altering the moving direction of the balls  3 ,  3 ′. In case of rotation of the sliding block  91  with respect to the rail  92 , the balls  3 ,  3 ′ move therebetween. The ball spacers  6  are arranged between adjacent paired balls  3 ,  3 ′ such that the balls don&#39;t contact each other directly. In case of rotation of the balls  3 ,  3 ′, the ball spacers  6  rotate reversely to the rotating direction of the balls  3 ,  3 ′ so as to reduce to the friction drag between the ball spacer  6  and the balls  3 ,  3 ′.  
         [0029]    In order to adjust the intervals between the ball spacer and the balls which applied in the above-mentioned preferred embodiments, the present invention may follow the method disclosed in U.S. Pat. No. 5,927,858 of using spacers with different thickness to use two different sized ball spacers in the circulation unit of same ball bearing, ball screw or linear rolling guide unit. Wherein the diameters of the middle sections of the two ball spacers are different so as to adjust intervals between the ball spacers and the balls of the ball bearing, ball screw or linear rolling guide unit.  
         [0030]    Due to the ball spacer of the present invention is provided with axial symmetrical cylindrical surfaces which separate the adjacent balls at both sides of the ball spacer, such that the collision between the adjacent paired balls and the noise of which can be prevented. The cylindrical surfaces of the ball spacer allow the rotation of which with respect to the balls so that almost there is no relative motion happened on the contacting point between the balls and the ball spacer and accordingly reduce the friction therebetween as well. Furthermore, the diameter of the middle section of the cylindrical surface of the ball spacer is minor than that of both end sections of the same, such that reduce the spaces of the balls occupied and as a result, the rolling device of the present invention may accommodate more balls as compared with the conventional ball spacer. The ball spacer is designed as having both spherical end surfaces which likes a sphere so as to prevent apparent interferences between the balls and the ball spacer.  
         [0031]    While we have shown and described various embodiments in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.