Patent Application
20130125690
1. Technical Field
The present disclosure generally relates to robotics, and particularly, to a robot arm assembly applied in an industrial robot.
2. Description of Related Art
An industrial robot may include a plurality of robot arms, a plurality of driving members driving the robot arms, and a plurality of transmission shafts connecting the driving members and the robot arms. Two or more transmission shafts may be sleeved together to save space. However, the above-mentioned robot may have a complicated structure wherein when one of the transmission shafts needs to be repaired, all the transmission shafts need to be disassembled. Disassembling all the transmission shafts may be inconvenient. In addition, because of space limitations, a plurality of gear assemblies may be provided between the driving members and the transmission shafts, or between the transmission shafts and the robot arms. The greater the number of gears used, the greater is the cumulative play or clearance between the teeth. Thus, transmission errors of the robot may become greater and precise repeatability may be lost.
Therefore, there is room for improvement within the art.
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 the several views.
Referring to
The base 10 includes a main body 11 and a cover portion 13. The main body 11 is substantially a hollow cylinder. The cover portion 13 covers one end of the main body 11 away from the third arm 40.
The first arm 20 includes a first arm portion 21 and a second arm portion 23. The first arm portion 21 includes a main body 211 and an extension portion 213 extending from the end of the main body 211 towards the base 10. The main body 211 is substantially a hollow cylinder. One end of the main body 211 opposite to the extension portion 213 is connected to the second arm portion 23. The extension portion 213 is substantially a hollow cylinder, and is sleeved in and rotatably connected to the main body 11 of the base 10. The second arm portion 23 includes a peripheral wall 231, a mounting wall 233 and two receiving portions 235. One end of the peripheral wall 231 is connected to one end of the first arm portion 21. The mounting wall 233 is plate-like, and is connected to and covers the other end of the peripheral wall 231 opposite to the first arm portion 21. A first mounting hole 2331 and a second mounting hole 2333 are symmetrically defined in the mounting wall 233. The two receiving portions 235 extend from the first mounting hole 2331 and the second mounting hole 2333 away from the first arm portion 21. Each of the two receiving portions 235 is hollow to receive some components of the second arm 30, and a part of the second driving mechanism 60 and the third driving mechanism 70.
Opposite ends of the second arm 30 are rotatably connected to the two receiving portions 235. The third arm 40 is rotatably placed on a central region of the second arm 30, and is perpendicular to the second arm 30.
The first driving mechanism 50 includes a first driving member 51, and a pair of gears 55. The first driving member 51 is securely placed on outside of the cover portion 13. One of the pair of gears 55 is rotatably placed on inside the cover portion 13, and is connected to the first driving member 51. Another one of the pair of gears 55 is securely placed on the extension portion 213, such that the first driving member 51 is capable of driving the first arm 20 to rotate around the first rotation axis A. The pair of gears 55 are bevel gears.
The second driving mechanism 60 includes a second driving member 61, a first transmission shaft 63, a first gear 65, and a second gear 67. The second driving member 61 is securely placed on outside of the cover portion 13 adjacent to the first driving member 51, and is connected to the first transmission shaft 63 to drive the first transmission shaft 63 to rotate. The first transmission shaft 63 is placed in the first arm portion 21. The first gear 65 is rotatably mounted on the periphery of the first mounting hole 2331. One end of the first gear 65 is connected to the first transmission shaft 63, and the other end of the first gear 65 protrudes out from the first mounting hole 2331 towards the second arm 30. The second gear 67 is securely placed on the second arm 30, and is engaged with the end of the first gear 65 towards the second arm 30, such that the second driving member 61 is capable of driving the second arm 30 to rotate around the second rotation axis B. The first gear 65 and the second gear 67 are bevel gears.
The third driving mechanism 70 is similar to the second driving mechanism 60, and is substantially symmetrical with the second driving mechanism 60. The third driving mechanism 70 includes a third driving member 71, a second transmission shaft 73, a third gear 75, a fourth gear 77, a fifth gear 78, and a sixth gear 79. The third driving member 71 is securely placed on outside the cover portion 1, and is substantially symmetrical with the second driving member 61 about the first driving member 51. The third driving member 71 is connected to the second transmission shaft 73 to drive the second transmission shaft 73 to rotate. The second transmission shaft 73 is placed in the first arm portion 21, and is substantially symmetrical with the first transmission shaft 63 about an axis of the first arm portion 21. The third gear 75 is rotatably mounted on the periphery of the second mounting hole 2333. One end of the third gear 75 is connected to the second transmission shaft 73, and the other end of the third gear 75 protrudes out from the second mounting hole 2333 towards the second arm 30. The fourth gear 77 is rotatably placed on one of the two receiving portions 235, and is engaged with the end of the third gear 75 adjacent to the second arm 30. The fifth gear 78 is rotatably placed on each of the two receiving portions 235 on which the fourth gear 77 is placed, and is connected to the fourth gear 77. The sixth gear 79 is securely mounted on the third arm 40, and is engaged with the fifth gear 78. Thus, the third driving member 71 drives the third arm 40 to rotate around the first rotation axis A by means of the second transmission shaft 73, the third gear 75, the fourth gear 77, the fifth gear 78, and the sixth gear 79. The third gear 75, the fourth gear 77, the fifth gear 78, and the sixth gear 79 are bevel gears.
The first transmission shaft 63 and the second transmission shaft 73 are placed inside the first arm 20, and are substantially symmetrical with each other about the axis of the first arm portion 21 of the first arm 20. Thus, the second driving member 61 and the third driving member 71 are symmetrically placed on the base 10, and the second driving member 61, the third driving member 71 are directly connected to the transmission shafts the first transmission shaft 63, the second transmission shaft 73 without additional gears. In addition, the number of gears necessary between the first transmission shaft 63, the second transmission shaft 73 and the second arm 30, the third arm 40 is less. Therefore, the number of gears used in the robot arm assembly 100 is less, the cumulative play or clearance is lower, such that loss of precision through transmission errors is much lower. Furthermore, when one of the driving mechanisms needs to be repaired, the driving mechanisms can be detached or taken down separately, which is very important for maintenance.
Finally, while the embodiments have been described and illustrated, the disclosure is not to be construed as being limited thereto. Various modifications can be made to the embodiment by those skilled in the art without departing from the true spirit and scope of the disclosure as defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201110367866.2 | Nov 2011 | CN | national |
