Abstract:
A robot arm assembly includes a first robot arm, a second robot arm, and a third robot arm. The first robot arm includes a first body and a backlash adjusting assembly received in the first body. The backlash adjusting assembly includes a base plate, a protruding shaft perpendicularly coupled to the base plate, and an adjusting member. The base plate defines a slotted hole. The adjusting member is detachably inserted into the slotted hole and is detachably coupled to first body. The second robot arm includes a second body and a first transmission assembly rotatably coupled to the second body. The first transmission assembly includes a first adjusting gear, a first intermediate gear, and a second adjusting gear. The first intermediate gear meshes the first and second adjusting gear. The second adjusting gear is coupled to the second body. The first intermediate gear is sleeved on the protruding shaft.

Description:
FIELD 
       [0001]    The present disclosure relates to robot arm assemblies, particularly to a robot arm assembly of a multi-axis robot. 
       BACKGROUND 
       [0002]    A robot may includes a base and a plurality of robot arms coupled in order. For example, a six axes robot may include a fourth robot arm, a fifth robot arm, and a sixth robot arm. A driver is received in the fourth robot arm and is configured to drive the fifth robot arm. A belt transmission structure or a gear transmission structure may interconnect the driver and the fifth robot arm. The sixth robot arm is a performing part of the robot for assembling with a clamper, a cutter, and a detector, for example. When in use, the sixth robot arm may be impacted by other objects adjacent to the robot. When a belt transmission structure is used in the robot, because the belt transmission structure has a poor structural rigidity, the fifth robot arm may deviated from its normal position, and the inner elements (such as reducer, or bearing, for example) of the robot may be damaged. When a gear transmission structure is used in the robot, a backlash between gears of the gear transmission structure may increase, and results in a low position accuracy. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]    The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout several views. 
           [0004]      FIG. 1  is an isometric view of an embodiment of a robot arm assembly including a first cover. 
           [0005]      FIG. 2  is a sectional view of the robot arm assembly of  FIG. 1 , taken along line II-II. 
           [0006]      FIG. 3  is a side view of the robot arm assembly of  FIG. 1  with the first cover removed. 
       
    
    
     DETAILED DESCRIPTION 
       [0007]    The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean “at least one.” 
         [0008]    The term “coupled” is defined as connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The connection can be such that the objects are permanently connected or releasably connected. 
         [0009]      FIGS. 1 and 2  show an embodiment of a robot arm assembly  100  including a first robot arm  10 , a second robot arm  30 , and a third robot arm  50 . The first robot arm  10  and the third robot arm  50  can couple two ends of the second robot arm  30 , respectively. 
         [0010]    In the illustrated embodiment, the robot arm assembly  100  can be used in a six axis robot. The first robot arm  10  can be capable of rotating about a first axis  1 , the second robot arm  30  can be capable of rotating about a second axis  2 , and the third robot arm  50  can be capable of rotating about a third axis  3 . The second axis  2  can be perpendicular to the first axis  1  and the third axis  3 . The first axis  1  can be substantially coaxial with the third axis  3 . The third robot arm  50  can be a performing part of the six axes robot and can be configured to assemble a cutter, or a clamp, for example. 
         [0011]    The first robot arm  10  can include a first body  11 , a first cover  13  covering the first body  11 , and a backlash adjusting assembly  17  received in the first body  11 . 
         [0012]    The first body  11  can be a substantially Z-shaped hollow housing, and can include a first receiving portion  111  and a second receiving portion  113  substantially parallel to the first receiving portion  111 . An end of the first receiving portion  111  can be coupled to an end of the second receiving portion  113 . A center axis of the first receiving portion  111  can be the first axis  1 . An outer sidewall of the second receiving portion  113 , parallel to the first axis  1 , can define an opening  115 . In the illustrated embodiment, the opening  115  can be located at a side of the second receiving portion  113  away from the first receiving portion  111 . In an alternative embodiment, the opening  115  can be located at a side of the second receiving portion  113  adjacent to the first receiving portion  111 . The second receiving portion  113  can include a connecting portion  117  at an end away from the first receiving portion  111 , for coupling with the second robot arm  30 . The first cover  13  can cover the opening  115 . The first cover  13  and the first body  11  can define a first receiving chamber  15 , cooperatively. 
         [0013]      FIG. 3  shows the backlash adjusting assembly  17 . The backlash adjusting assembly  17  can be coupled to an inner sidewall of the second receiving portion  113  opposite to the opening  115 , and can be received in the first receiving chamber  15 , for adjusting a backlash between gears. The backlash adjusting assembly  17  can include a base plate  171 , a protruding shaft  173  protruding from the base plate  171 , and a plurality of adjusting members  175 . 
         [0014]    The base plate  171  can be substantially rectangular, and can define a plurality of adjusting holes  1711 . In the illustrated embodiment, the adjusting holes  1711  are slotted holes, and the number of the adjusting holes  1711  is four. For example, an alternative embodiment, the adjusting holes  1711  can be kidney holes, rectangular holes. The protruding shaft  173  can be substantially columnar, and can protrude from a center of the base plate  171  towards the opening  115 . The adjusting members  175  can be inserted into the adjusting holes  1711 , and threaded with the inner sidewall of the second receiving portion  113 , thereby the base plate  171  can be fixed to an inner sidewall of the first body  11 . In the illustrated embodiment, the adjusting members  175  can be screws. When a position of the adjusting members  175  received in the adjusting holes  1711  is adjusted, a position of the base plate  171  relative to the second receiving portion  113  can be changed accordingly. 
         [0015]    The second robot arm  30  can be rotatably coupled to the first robot arm  10 , and can include a second body  31 , a second cover  33  covering the second body  31 , and a first transmission assembly  35  fixedly coupled to the second body  31 . 
         [0016]    The second body  31  can be a substantially L-shaped hollow housing, and can include a first connecting portion  311  and a second connecting portion  313  protruding from the first connecting portion  311 . The first connecting portion  313  can be rotatably coupled to the connecting portion  117  of the first robot arm  10 . A center axis of the first connecting portion  311  can be the second axis  2 . The second connecting portion  313  can be substantially parallel to the first receiving portion  111 . 
         [0017]    The second body  31  can define an opening (not labeled) corresponding to the second cover  33 , and the second cover  33  can cover the opening. The second body  31  and the second cover  33  can define a second receiving chamber  37 , cooperatively. The second receiving chamber  37  can communicate with the first receiving chamber  15 . The second receiving chamber  37  can include a first accepting portion  371  in the first connecting portion  311 , and a second accepting portion  373  in the second connecting portion  373 . The first accepting portion  371  can communicate with the second accepting portion  373 . 
         [0018]    The first transmission assembly  35  can be received in the first receiving chamber  15 , and can include a first bevel gear  351 , a second bevel gear  353 , a first adjusting gear  355 , a first intermediate gear  357 , and a second adjusting gear  359 . In the illustrated embodiment, the first adjusting gear  355 , the first intermediate gear  357 , and the second adjusting gear  359  are spur gears. 
         [0019]    The first bevel gear  351  can be received in the first receiving portion  111 , and can be rotatable about the first axis  1 . The second bevel gear  353  can mesh with the first bevel gear  351 , and a rotation axis of the second bevel gear  353  can be perpendicular to the first axis  1 . The first adjusting gear  355  can be coaxially stacked on the second bevel gear  353 , and can be received in the second receiving portion  113 . The first adjusting gear  355  can be fixed to the second bevel gear  353 . The first intermediate gear  357  can be rotatably sleeved on the protruding shaft  173  of the backlash adjusting assembly  17 , and can mesh with the first adjusting gear  355 . The second adjusting gear  359  can be located at a side of the first intermediate gear  357  away from the first adjusting gear  355 , and can mesh with the first intermediate gear  357 . A center axis of the second adjusting gear  359  can be the second axis  2 . The first adjusting gear  355 , the first intermediate gear  357 , and the second adjusting gear  359  can be received in the second receiving portion  113  and can correspond to the opening  115 . Observing or adjusting a backlash between the first adjusting gear  355  and a first intermediate gear, and a backlash between the first intermediate gear  357  and the second adjusting gear  359  can be convenient. 
         [0020]    The third robot arm  50  can be rotatably coupled to the second robot arm  30 , and can be partially received in the first receiving chamber  15  and the second receiving chamber  37 . The third robot arm  50  can include a third body  53  and a second transmission assembly  55  coupled to the third body  53 . 
         [0021]    The third body  53  can include a slave portion  531  and a mounting portion  533  located at an end of the slave portion  531 . The slave portion  531  can substantially be a rod, and can be rotatable about the third axis  3 . The slave portion  531  can be received in the second accepting portion  373 , and an end of the slave portion  531  opposite the mounting portion  533  can be fixed to the second transmission assembly  55 . The mounting portion  533  can protrude from the second connecting portion  313  of the second body  31 , and can be configured to assemble a cutter, or a clamp, for example. 
         [0022]    The second transmission assembly  55  can be partly received in the first chamber  15 , and can extend to the first accepting portion  371 . The second transmission assembly  55  can include a third bevel gear  551 , a fourth bevel gear  553 , a third adjusting gear  555 , a second intermediate gear  556 , a fourth adjusting gear  557 , a fifth bevel gear  558 , and a sixth bevel gear  559 . In the illustrated embodiment, the third adjusting gear  555 , a second adjusting gear  556 , and the fourth adjusting gear  557  are spur gears. 
         [0023]    The third bevel gear  551  can be located along the first axis  1 , and can be coaxially received in the first bevel gear  351 . The fourth bevel gear  553  can mesh with the third bevel gear  351 , and can be coaxially inserted into the second bevel gear  553  and the first adjusting gear  355 . The third adjusting gear  555  can be fixedly sleeved on the fourth bevel gear  553 , and can be stacked on the first adjusting gear  355  without interference, thus an axis of the third adjusting gear  555  can be perpendicular to the first axis  1 . The second intermediate gear  556  can be rotatably sleeved on the protruding shaft  173  of the backlash adjusting assembly  17 , and can be stacked on the first intermediate gear  357  without interference. The second intermediate gear  556  can mesh with the third adjusting gear  555 . The fourth adjusting gear  557  can mesh with the second intermediate gear  556 , and can be stacked on the second adjusting gear  359 , thus an axis of the fourth adjusting gear  557  can overlap with the second axis  2 . The third adjusting gear  555  and the fourth adjusting gear  557  can be located at opposite sides of the second intermediate gear  556 . The fifth bevel gear  558  can be rotatably inserted into the second adjusting gear  359 , and can be fixed to the fourth adjusting gear  557 . Teeth of the fifth bevel gear  558  can extend out from the second receiving portion  113 , and can extend to the first accepting portion  371 . The sixth bevel gear  559  can be received in the first accepting portion  371 , and can mesh with the fifth bevel gear  558 . The fifth bevel gear  559  can be received in the first accepting portion  371 , and can mesh with the fifth bevel gear  558 . An axis of the sixth gear  559  can overlap with the third axis  3 . The sixth bevel gear  559  can be fixedly sleeved on the slave portion  531  of the third body  53  to rotate the slave portion  531  and the mounting portion about the third axis  3 . 
         [0024]    In assembly, the base plate  171  of the backlash adjusting assembly  17  being mounted on the inner sidewall of the first body  11 , and the adjusting members  175  can lock the base plate  171  and the first body  11 . The third bevel gear  551  can be rotatably sleeved on the first bevel gear  351 . The first bevel gear  351  and the third bevel gear  551  can be rotatably received in the first body  11  along the first axis  1 . The fourth bevel gear  553  can mesh with the third bevel gear  551 . The second bevel gear  353  can be rotatably sleeved on the fourth bevel gear  553 , and can mesh with the first bevel gear  351 . The first adjusting gear  355  can be rotatably sleeved on the fourth bevel gear  553 , and can be stacked on the second bevel gear  353 . The first intermediate gear  357  can be rotatably sleeved on the protruding shaft  173 , and can mesh with the first adjusting gear  355 . The third adjusting gear  555  can be securely sleeved on the fourth bevel gear  553 , and can be stacked on the first adjusting gear  355 . The second intermediate gear  556  can be rotatably sleeved on the protruding shaft  173 , and can be stacked on the first intermediate gear  357  and can mesh with the third adjusting gear  555 . The second adjusting gear  359  can be received in the first receiving chamber  15  along the second axis  2 , and can mesh with the first intermediate gear  357 . The fourth adjusting gear  557  can be stacked on the second adjusting gear  359 , and can mesh with the second intermediate gear  556 . 
         [0025]    The first connecting portion  311  of the second body  31  can be inserted into the connecting portion  117  of the first body  11 . The fifth bevel gear  558  can be rotatably received in the first accepting portion  371 . A shaft portion of the fifth bevel gear  558  can be rotatably inserted into the second adjusting gear  359 , and a distal end of the shaft portion of fifth bevel gear  558  can be fixed to the fourth adjusting gear  557 . Teeth of the fifth bevel gear  558  can be received in the first accepting portion  371 . 
         [0026]    The sixth bevel gear  559  can be securely sleeved on the slave portion  531  of the third body  53 . The sixth bevel gear  559  and the slave portion  531  can be positioned in the second accepting portion  373  along the third axis  3 , and the sixth bevel gear  559  can mesh with the fifth bevel gear  558 . The first cover  13  can cover the opening  115 , and can lock with the first body  11 . The second cover  33  can cover the opening defined on the second body  31 , and can lock with the second body  31 . 
         [0027]    In use, when the first robot arm  10  rotates about the first axis  1 , the first body  11  of the first robot arm  10  can rotate the second robot arm  30  and the third robot arm  50  about the first axis  1 . When the first bevel gear  351  of the first transmission assembly  35  is rotated, the second robot arm  30  and the third robot arm  50  can be rotated about the second axis  2  driven by the second bevel gear  353 , the first adjusting gear  355 , the first intermediate gear  357 , and the second adjusting gear  359 . When the third bevel gear  551  of the second transmission assembly  55  is rotated, the third body  53  can rotates about the third axis  3  driven by the fourth bevel gear  553 , the third adjusting gear  555 , the second intermediate gear  556 , the fourth adjusting gear  557 , the fifth bevel gear  558 , and the sixth bevel gear  559 . 
         [0028]    When a backlash occurs between the first transmission assembly  35  and the second transmission assembly  55  during use, the backlash can be adjusted. The first cover  13  can open and loosen the adjusting members  175 . The base plate  171  can move along a direction perpendicular to a imaginary line connecting a center point of the first adjusting gear  355  and a center point of the second adjusting gear  359  (that is perpendicular to the first axis  1 ), and can relock the adjusting members  175 . Therefore, a position of the base plate  171  relative to the second receiving portion  113  can be adjusted, and a distance between the first intermediated gear  357  and the first adjusting gear  355  can be decreased, and a distance between the first intermediated gear  357  and the second adjusting gear  359  can be decreased. In addition, a distance between the second intermediated gear  556  and the third adjusting gear  555  can be decreased. A distance between the second intermediated gear  556  and the fourth adjusting gear  557  can be decreased. 
         [0029]    In an alternative embodiment, structures of the first transmission assembly  35  and the second transmission assembly  55  can be different, such as the fifth bevel gear  558  and the sixth bevel gear  559  can be omitted and the third adjusting gear  555 , the second intermediate gear  556 , and the fourth adjusting gear  557  can be bevel gears. A shape of the first body  11  can be other shapes, such as columnar. The first bevel gear  351 , the second bevel gear  353 , the third bevel gear  551 , and the fourth bevel gear  553  can be replaced with spur gears. 
         [0030]    It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes can be made thereto without departing from the spirit and scope of the embodiments or sacrificing all of its material advantages.