Abstract:
A device of an improvement on the structure of linear actuator primarily includes a motor body and an output shaft, and at one end of the motor body fixed a gear case in which two sets of planetary gear trains fitted, by which a sun gear of one of the planetary gear trains is disposed at the top of output shaft; according to the above mentioned structure, the mesh teeth number between planetary gear is more to enhance the efficiency of resisting shocks and absorbing vibrates for attaining the intention of reducing cost, decreasing weight, diminishing volume, and promoting better outlook.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to an improvement on the structure of linear actuator, more particularly, to an improvement on the structure of linear actuator to gain the effect of weight decreasing, volume shrinkage, and cost reducing.  
       BACKGROUND OF THE INVENTION  
       [0002]     Conventional linear actuator fixes a threaded pole in front end of the motor, and an escalating threaded nut, mounted on the outside edge of the threaded pole, moves in axial direction while the threaded pole rotates diametrically; whereas the rotating speed of conventional motor is extremely fast, so that linear actuator fixed a set of gear slow-down device between output shaft and threaded pole to buffer the rotating speed of the threaded pole.  
         [0003]     Refer to  FIG. 4  and  FIG. 5 , conventional linear actuator primarily comprises a motor body a and an output shaft a 1  which mesh with first big decelerating gear b in the edge of front side; whereas the first big decelerating gear b is disposed under one side of output shaft a 1 , and in the front center of big decelerating gear b fixes a first small decelerating gear b 1  which meshes with second big decelerating gear c; whereas the second big decelerating gear c is disposed under the other side of output shaft a 1  beside the first big decelerating gear b, and in the center of second big decelerating gear fixes a second small decelerating gear c 1  which meshes with the third big decelerating gear d; In front end of shaft center of the third big decelerating gear d fixes a threaded pole d 1  with an escalating threaded nut d 2  mounted on.  
         [0004]     As mentioned above, the output shaft a 1  of conventional linear actuator drives the first big decelerating gear b to rotate, and rolls the first small decelerating gear b 1  simultaneously, and therefore takes advantage of the mechanic functionality of the number of the teethes of output shaft a 1  less than that of the first big decelerating gear d to gain the purpose of slowing down the speed; similarly, the mesh between first small decelerating gear b 1  and the second big decelerating gear c, and the second small decelerating gear c 1  together with third big decelerating gear d are also designed to meet the purpose of slowing down the rotating speed.  
         [0005]     Accordingly, the mesh point between gears of conventional linear actuator only in one part makes the actuation strength concentrate on one or two gears. In order to prevent concentrating strength from causing collapse, usage of better enduring material quality and weight and volume emphasis will increase the manufacturing cost and weaken the market competition.  
       SUMMARY OF THE INVENTION  
       [0006]     It is therefore a primary object of the present invention to provide a newly device of improvement on the structure of linear actuator.  
         [0007]     It is the further object of the present invention to provide a kind of motor, which can attain the purpose of reducing cost, decreasing weight and shrinking volume.  
         [0008]     The present invention provides a device of improvement on the structure of linear actuator, primarily includes a motor body, an output shaft, and a motor case, wherein the improvement is characterized by: the inner side of motor case arranged four bolt grooves and four long bolts, and at one end of top motor cover with gear case at outer side in which contains a ring gear, a top planetary gear train, and a bottom planetary gear train; whereas the sun gear of bottom planetary gear train mounted on the top of output shaft, and at the top of the small gear bearing of bottom planetary gear train fixed a bearing gear, besides, on the top of the outer gear case arranged a top cover with a power cord hole and stationary casing at one side to manage multiple extendable power cords.  
         [0009]     In addition, the present invention of an improvement on the structure of linear actuator possessed more teeth on planetary gear train and therefore has better strength to resist shocks and vibrations. Consequently manufactured by high quality material is not necessary so as to reduce material cost; the transmission ratio can be changed by changing the sun gear of the output shaft, moreover the long bolt located in the bolt groove of motor case, power cords hide in the top cover makes no power cords and bolts sling outside to enjoy the cost reducing, weight decreasing, and volume shrinkage, and get a better feature. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0010]     Embodiments of the present invention will be described herein below by reference to the accompanying drawings and an adequate practical example: First of all, referring to  FIG. 1             2             3 , the improvement on the structure of linear actuator in accordance with the present invention primarily comprise a motor body  1           output shaft  11  and motor case  12 , wherein the improvement is characterized as follows:  
         [0011]     The inner side of motor case  12  arranged four bolt grooves  121  and four long bolts insert into the four grooves respectively, and at one end of the linear actuator fixed a top motor cover  14  with gear case  20  and four nuts  15  opposite to the four long bolts  13  respectively outside of the top motor cover, whereas the four long bolts  13  together with nuts  15  fasten on the top motor cover  14  and gear case  20  stationary to one end of motor case  12 .  
         [0012]     Furthermore, in the inner side of gear case  20  arranged with a ring gear  21           a top planetary gear train  22  and a bottom planetary gear train  23 , at the top center of the gear case  20  set up a gear case hole  201 ; and within the inner of the top planetary gear train  22  and bottom gear train  23  fitted at least two planetary gears  220             230 , on top of which arranged a small gear bearing  221             231 , and a sun gear  222             232  set up among the planetary gears  220             230  respectively, the sun gear  232  of bottom planetary gear train  23  mounted on top of the output shaft  11 , wherein the sun gear  222  of top planetary gear  22  mounted on top of the small gear bearing  231  of bottom planetary gear train  23 . At the top of small gear bearing  221  of top planetary gear train  22  fixes a bearing gear  223 , a top cover  30  fitted outside of gear case  20 .  
         [0013]     A top cover hole  301  arranges in the center of top cover  30 , the threaded pole  4  insert through the inner side of gear case hole  201  as well as top cover hole  301 , the bottom end of the threaded pole  4  connected with bearing gear  223 , on one side of the top cover  30  arranged a power cord hole  31 ;  
         [0014]     At one side of bearing gear  223  set up a side gear  24  with a side threaded pole  25  on top of the side gear  24 ;  
         [0015]     At the inner side of power cord hole  31  fixes a stationary casing  310  to hold a plurality of extended power cords  16 .  
         [0016]     As shown above, refer to the present invention of a device of an improvement on the structure of linear actuator, wherein the outer edge of the threaded pole  4  fixes an escalating nut which could be moved back and forth along the threaded pole  4  by the rotation of the threaded pole  4  when rolls the output shaft  11  by means of the sun gear  232           top planetary gear train  22  and bottom planetary gear train  23  to transmit the power to roll the threaded pole  4 ; in addition, planetary gear drive by sun gear, and fixed ring gear, then output by small gear bearing to attain the purpose of speed deceleration; the deceleration method of the present invention of an improvement on the structure of linear actuator is driven by using sun gear  232  of bottom planetary gear  23  as active wheel to actuate planetary gear  230 , and fixed the ring gear to match sun gear  222  of small gear bearing  231  as output terminal to drive top planetary gear  22  and transmit actuation to threaded pole  4  by means of the bearing gear  223  at top of small gear bearing  221 . Owning to the fact that present invention has two sets of planetary gear, the rotating speed of the output shaft  11  decelerate twice before transmitting to threaded pole  4  so as to efficiently slow down the rotating speed of threaded pole  4 .  
         [0017]     As mentioned above, refer to the present invention of a device of an improvement on the structure of linear actuator, wherein if those two sets of planetary gear train contains two planetary gears respectively; in the planetary gear train, both the sun gear  222             232  together with planetary gear  220             230 , and planetary gear  220             230  together with ring gear  21  has two mesh points; similarly, if the planetary gear contains three planetary gear  220             230 , then mesh points increase into three, the mesh teeth increase because of more mesh points, and therefore enhance the ability of shock and vibration resistance without usage of high degree of material so that more optional choice of materials could be considered to compact the gear size and design a quite compact gear to meet the purpose of reducing material cost and condense gear size.  
         [0018]     Furthermore, refer to the present invention of a device of an improvement on the structure of linear actuator, wherein side threaded pole  25  could be connected with a VR (variable resistant), and rotated simultaneously with side gear  24  by the driven of bearing gear  223 , and sensed rotating times and position by means of the VR control mechanism to attain the effect of detect and control the shifting position of escalating threaded nut.  
         [0019]     Moreover, refer to the present invention of a device of an improvement on the structure of linear actuator, wherein the sun gear  232  of motor output shaft  11  can be changed to alter the transmission ratio of top planetary gear train  22  and bottom planetary gear train  23  to gain the required effect of adjusting the shifting speed of escalating threaded nut; furthermore, because of the long bolts  13  located inside the bolt grooves of motor case  12  and power cords hided in the top cover  30 , a better outlook happens by handling the outlook influence able factors of long bolts  13  and power cords  16 .  
         [0020]     In summary, the present invention of “a device of improvement on the structure of linear actuator” could actually reduce cost, decrease weight, diminish volume, and promote the effect of better outlook to possess the characteristics of practicality and progress.  
         [0021]     Accordingly, to promote the progress in science and the useful arts, the invention is disclosed and is intended to be limited only by scope of the appended claim.  
       BRIEF DESCRIPTION OF THE DIAGRAM  
       [0022]      FIG. 1  the exploded perspective view of the present invention.  
         [0023]      FIG. 2  the cross-sectional perspective view of the present invention.  
         [0024]      FIG. 3  the consolidated perspective view of the present invention.  
         [0025]      FIG. 4  the side cross-sectional view of the conventional linear actuator.  
         [0026]      FIG. 5  the front cross-sectional view of the conventional linear actuator.  
                                               1   motor body   4   threaded pole       11   output shaft   12   motor case       13   long bolt   14   motor top cover       15   threaded nut   16   power cords       20   gear case   21   ring gear       22   top planetary gear train   23   bottom planetary gear train       24   side gear   25   side threaded pole       30   top cover   31   power cord hole       121   bolt groove   201   gear case hole       223   bearing gear   301   top cover hole       310   casing       220         230   planetary gear       221         231   small gear bearing       222         232   sun gear