Abstract:
An industrial robot with a gear transmission mechanism is disclosed. The industrial robot comprises a base; a robot arm assembly rotatably connected to the base; the robot arm assembly comprising a gear box; a first driving member positioned on the gear box, the first driving member having a first driving shaft; a first transmission mechanism positioned in the gear box, wherein the first transmission mechanism has at least two gears meshing with each other and a fixed shaft fixed to the base, one of the at least two gears is connected to the first driving shaft, and another one of the at least two gears is rotatably sleeved on the fixed shaft, and fixed to the gear box.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present disclosure generally relates to robot technologies, and particularly to an industrial robot with a gear transmission mechanism. 
         [0003]    2. Description of the Related Art 
         [0004]    Referring to  FIG. 4 , a six-axis robot  100  is schematically shown. The robot  100  includes a base  11 , a bracket  12  rotatably connected to the base  11 , a lower arm  13  rotatably connected to the bracket  12 , a middle joint  14  connected to the lower arm  13 , an upper arm  15  rotatably connected to the middle joint  14  and an end joint  17  rotatably connected to the end of the upper arm  15 . The bracket  12 , the lower arm  13 , the middle joint  14  and the upper arm  15  are respectively capable of rotating about a first axis  161 , a second axis  162 , a third axis  163  and a fourth axis  164 . The end joint  17  includes a fifth shaft (not shown) rotatably connected to the upper arm  15  and a sixth shaft (not shown) rotatably connected to the fifth shaft. The fifth and sixth shafts are respectively capable of rotating about a fifth axis  165  and sixth axis  166 . An actuator, such as a cutting tool, a clamping tool or a detector can be mounted on the sixth shaft to perform a predetermined action. 
         [0005]    Generally, the robot  100  is provided with an electric motor and a speed reducer (not shown) to drive the upper arm  15 . The speed reducer may be a rotary vector (RV) speed reducer or a harmonic drive (HD) speed reducer. However, both the RV speed reducer and the HD speed reducer are expensive. In addition, cables connected to the RV speed reducer or the HD speed reducer for supplying power or control signal directions have to be received inside the upper arm  15 , and as a result the cables are vulnerable to damage by abrasion or by being twisted. 
         [0006]    Therefore, there is room for improvement within the art. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0007]    The components in the drawings are not necessarily drawn to scale, the emphasis instead placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views. 
           [0008]      FIG. 1  is an isometric, assembled view of an embodiment of an industrial robot including a first enclosure and a second enclosure. 
           [0009]      FIG. 2  is a cross-sectional view of the first enclosure of  FIG. 1 . 
           [0010]      FIG. 3  is a cross-sectional view of the second enclosure of  FIG. 1 . 
           [0011]      FIG. 4  is a schematic view of a related art industrial robot. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    Referring to  FIG. 1 , an embodiment of an industrial robot  200  comprises a base  20 , and a robot arm assembly  30  rotatably connected to the base  20 . 
         [0013]    Referring to  FIGS. 3 and 4 , the robot arm assembly  30  comprises a gear box  31 , a first driving member  33 , a second driving member  35 , a first transmission mechanism  36 , and a second transmission mechanism  37 . The first transmission mechanism  36  and the second transmission mechanism  37  are positioned in the gear box  31 . 
         [0014]    The gear box  31  comprises a main body  311 , a first cover  313 , and a second cover  315 . The main body  311  comprises a first box  3111  and a second box  3113  connected to the first box  3111 . The first cover  313  is fixed to the first box  3111 , and together with the first box  3111  forms a first receiving groove  3115  for receiving the first transmission mechanism  36 . The second cover  315  is fixed to the second box  3113 , and, with the second box  3113 , forms a second receiving groove  3116  for receiving the second transmission mechanism  37 . In an illustrated embodiment, the second box  3113  is substantially perpendicularly connected to the first box  3111 . 
         [0015]    The first driving member  33  is fixed to a top wall of the first box  3111 , and the second driving member  35  is fixed to the second cover  315 . The first driving member  33  comprises a first driving shaft  331  extending through the top wall of the first box  3111 , and the second driving member  35  comprises a second driving shaft  351  extending through the second cover  315 . In the illustrated embodiment, the first driving member  33  and the second driving member  35  are servo motors. 
         [0016]    The first transmission mechanism  36  comprises a gap adjusting assembly  360 , a first gear  361 , a second gear  362 , a third gear  363 , a fourth gear  364 , a fixed shaft  365 , a first bearing  366 , a second bearing  367 , a third bearing  368 , and a fourth bearing  369 . The first gear  361  meshes with the second gear  362 . The second gear  362  is fixed to the third gear  363 . The third gear  363  meshes with the fourth gear  364 . The fourth gear  364  is rotatably sleeved on the fixed shaft  365 . The gap adjusting assembly  360  adjusts a gap between the third gear  363  and the fourth gear  364 . In the illustrated embodiment, the third gear  363  and the fourth gear  364  are bevel gears. 
         [0017]    The first bearing  366  and the third bearing  368  are fixed to the first box  3111 . The second bearing  367  and the fourth bearing  369  are fixed to the first cover  313 . The first bearing  366  is aligned with the second bearing  367 , and the third bearing  368  is aligned with the fourth bearing  369 . 
         [0018]    The first gear  361  is fixed to the first driving shaft  331 . The third gear  363  comprises a gear shaft (not labeled), and the first bearing  366  and the third bearing  368  are positioned on opposite ends of the gear shaft of the third gear  363 . The second gear  362  fixedly sleeves on the gear shaft of the third gear  363 . The fourth gear  364  is fixed to a bottom wall of the gear box  31 . The fixed shaft  365  extends through the third bearing  368  and the fourth bearing  369 , and is fixed to the base  20 . 
         [0019]    The third gear  363  defines a positioning hole  3631  in an end adjacent to the first bearing  366 . The gap adjusting assembly  360  comprises an elastic member  3601 , a fastener  3603 , and a resisting member  3605 . The resisting member  3605  and the elastic member  3601  are received in the positioning hole  3631  in that order. The fastener  3603  is fixed on the first box  3111 , and abuts against the elastic member  3601 . In the illustrated embodiment, the resisting member  3605  is a steel ball, the elastic member  3601  is a compression spring, and the fastener  3603  is a screw. The fastener  3603  can be moved towards the third gear  363  by a screwdriver (not shown), and then the third gear  363  is driven to move by the resisting member  3605 , such that the gap between the third gear  363  and the fourth gear  364  decreases, because the third gear  363  and the fourth gear  364  are bevel gears. That is, the third gear  363  can be driven to move to mesh with the fourth gear  364  more tightly by adjusting the fastener  3603 . 
         [0020]    When the first driving member  33  is working, the first driving shaft  331  drives the first gear  361  to rotate, and then the first gear  361  drives the second gear  362  to rotate. The second gear  362  drives the third gear  363  to rotate on the first bearing  366  and the second bearing  367 . The third gear  363  drives the fourth gear  364  to rotate. The gear box  31  rotates about the fixed shaft  365  together with the fourth gear  364  because the fourth gear  364  is fixed to the gear box  31 . 
         [0021]    In the illustrated embodiment, the first gear  361 , the second gear  362 , the third gear  363 , and the fourth gear  364  are spur involute gears. A rotating axis of the first driving shaft  331 , a rotating axis of the second gear  362 , and a rotating axis of the fourth gear  364  are substantially parallel to each other. The manufacturing costs of the first gear  361 , the second gear  362 , the third gear  363 , and the fourth gear  364  are relatively low, comparing with the related art speed reducer. Therefore, the industrial robot  200  has a low manufacturing cost. A total reduction ratio of the first transmission mechanism  36  can be adjusted by changing a number of teeth of the first gear  361 , the second gear  362 , the third gear  363 , and the fourth gear  364 . For example, a reduction ratio between the first gear  361  and the second gear  362  may be 11, and a reduction ratio between the third gear  363  and the fourth gear  364  may be 5, thus the total reduction ratio of the first transmission mechanism  36  is 55. 
         [0022]    In an alternative embodiment, the first transmission mechanism  36  may only comprise the first gear  361  and the fourth gear  364  directly meshing with the first gear  361 . 
         [0023]    The second transmission mechanism  37  has a similar structure to the first transmission mechanism  36 . The second transmission mechanism  37  comprises a gap adjusting assembly  370 , a fifth gear  371 , a sixth gear  372 , a seventh gear  373 , an eighth gear  374 , an output shaft  375 , a fifth bearing  376 , a sixth bearing  377 , a seventh bearing  378 , and an eighth bearing  379 . The fifth gear  371  meshes with the sixth gear  372 . The sixth gear  372  is fixed to the seventh bearing  378 . The seventh bearing  378  meshes with the eighth gear  374 , and the eighth gear  374  is fixedly sleeved on the output shaft  375 . The gap adjusting assembly  370  of the second transmission mechanism  37  has the same structure as the gap adjusting assembly  360  of the first transmission mechanism  36 . The gap adjusting assembly  370  adjusts a gap between the seventh gear  373  and the eighth gear  374 . 
         [0024]    The fifth bearing  376  and the seventh bearing  378  are fixed to the second box  3113 . The sixth bearing  377  and the eighth bearing  379  are fixed to the second cover  315 . The fifth bearing  376  aligns with the sixth bearing  377 , and the seventh bearing  378  aligns with the eighth bearing  379 . 
         [0025]    When the second driving member  35  is working, the second driving shaft  351  rotates the fifth gear  371 , and the fifth gear  371  rotates the sixth gear  372 . The sixth gear  372  rotates the seventh gear  373  on the fifth bearing  376  and the sixth bearing  377 . The seventh gear  373  rotates the eighth gear  374 . The output shaft  375  rotates on the seventh bearing  378  and the eighth bearing  379  together with the fourth gear  364  because the eighth gear  374  is fixed to the output shaft  375 . 
         [0026]    In the illustrated embodiment, the fifth gear  371 , the sixth gear  372 , the seventh gear  373 , and the eighth gear  374  are spur involute gears. A rotating axis of the second driving shaft  351 , a rotating axis of the sixth gear  372 , a rotating axis of the eighth gear  374 , and a rotating axis of the output shaft  375  are substantially parallel to each other. The manufacturing costs of the fifth gear  371 , the sixth gear  372 , the seventh gear  373 , and the eighth gear  374  are low, compared with the related art speed reducer. Therefore, the manufacturing cost of the industrial robot  200  is further reduced. A total reduction ratio of the second transmission mechanism  37  can be adjusted by changing a number of teeth of the fifth gear  371 , the sixth gear  372 , the seventh gear  373 , and the eighth gear  374 . For example, a reduction ratio between the fifth gear  371  and the sixth gear  372  may be  11 , and a reduction ratio between the seventh gear  373  and the eighth gear  374  may be  5 , thus the total reduction ratio of the second transmission mechanism  37  is  55 . 
         [0027]    In an alternative embodiment, the first transmission mechanism  36  may only comprise the fifth gear  371  directly meshed with the eighth gear  374 . 
         [0028]    While the present disclosure has been described with reference to particular embodiments, the description is illustrative of the disclosure and is not to be construed as limiting the disclosure. Therefore, various modifications can be made to the embodiments by those of ordinary skill in the art without departing from the true spirit and scope of the disclosure, as defined by the appended claims.