JPH0429990Y2 - - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to a robot joint with a simple structure.

B. Summary of the invention This invention is a joint of a robot that connects a first member and a second member, in which one end of the second shaft is fixed at the center of the first shaft, and both ends of the first shaft are connected to the first member. a second gear rotatably supported by a second member, the other end of the second shaft being rotatably supported by a second member, and meshing with both of a pair of first gears rotatably provided at both ends of the first shaft; is fixed to the second member, and a driving source is connected to each of the pair of first gears, so that the second member can pivot and rotate relative to the first member with a simple structure.

C. Prior Art A robot such as a manipulator is composed of a plurality of members that are interlocked and connected via joints so that they can perform various tasks. Each joint has at least one degree of freedom, and in some cases may have two or three degrees of freedom. Each degree of freedom has a separate drive source and power transmission mechanism.

D Problems to be solved by the invention However, when one joint of a conventional robot has multiple degrees of freedom, a drive source and a power transmission mechanism are provided for each degree of freedom, and as a result, the joint part has multiple degrees of freedom. growing. Furthermore, the drive sources and power transmission mechanisms for each degree of freedom cannot be accommodated in the arm, resulting in one end of the arm becoming extremely large, which impairs the workability of the robot.

In addition, if you try to avoid this and store the drive source inside the arm, it will be installed at a location away from the joints and a complicated power transmission mechanism will be required, which will result in poor responsiveness. This will lead to performance deterioration.

Therefore, an object of the present invention is to provide a robot joint that eliminates such drawbacks.

E. Means for Solving the Problems In order to achieve the above object, the present invention uses a differential gear mechanism in the joints of the robot.

That is, a connecting shaft is provided at the distal end of the first member, in which one end of the second shaft is connected to the center of the first shaft, and the first shaft is rotatably arranged at right angles to the axis of the first arm; A second gear meshing with both of a pair of first gears rotatably attached to both ends of the first shaft and coupled to a second member is rotatably attached to the second shaft, and each of the pair of first gears A pair of drive sources arranged in parallel within the first member are individually connected to each other.

F Effect First, the case where the second member is rotated with respect to the first member will be explained. In this case, the output shafts of the pair of drive sources are rotated in the same direction. Then, each of the pair of first gears rotates in opposite directions, and the second gear that meshes with both of the first gears rotates around the second axis without revolving around the first axis. Since the second gear is integrated with the second member, the second member will rotate relative to the first member.

Next, a case will be described in which the second member is rotated relative to the first member. In this case, the output shafts of the pair of drive sources are rotated in opposite directions. Then, the pair of first gears rotate in the same direction, and a force acts that causes the second gears to rotate in mutually opposite directions. Therefore, the second gear does not rotate around the second shaft, but the second shaft, the second gear, and the pair of first gears rotate together around the first shaft, and the first member The second member will pivot relative to the second member.

In addition, if the rotation directions of a pair of drive sources are the same but the relative speeds are different, the second member will undergo a pivoting motion relative to the first member, and if the rotation directions of the pair of drive sources are opposite but the relative speeds are different, the second member will rotate. One member is accompanied by a rotational movement of the second member.

G. Embodiments Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

A cross-sectional view of the joint of the robot according to the present invention is shown in FIG. As shown in the figure, a connecting shaft 2 is rotatably provided at the right end of a first arm 1 as a first member. The connecting shaft 2 is formed into a T-shape by integrally connecting one end of the second shaft 2b to the center of the first shaft 2a, and the first shaft 2a is perpendicular to the axis of the first arm 1. Both ends thereof are rotatably supported via bearings 3, respectively. A pair of first bevel gears 4a and 4b are rotatably provided at both ends of the first shaft 2a via bearings 5. First bevel gears 4a and 4b
are gears having the same shape, both having a large bevel tooth portion 6 and a small bevel tooth portion 7. Bearings 8 and 9 are mounted on the second shaft 2b.
A second bevel gear 10 is rotatably attached via a plurality of bolts 11. It is integrally coupled with a second arm 12 as a second member. In addition, 1
3 is a nut screwed into the second shaft 2b to fix the bearing 9.

A drive source 14a and a drive source 14b are housed in parallel in the first arm 1, and a bevel gear 15a that meshes with the large bevel tooth portion 6 of the first bevel gear 4a is attached to an output shaft (not shown) of the drive source 14a. On the other hand, the first bevel gear 4 is connected to the output shaft (not shown) of the drive source 14b.
A bevel gear 15b that meshes with the large bevel tooth portion 6 of b is attached. These driving sources 14a, 14b
In this embodiment, the motor is composed of a motor and a deceleration mechanism without backlash.

Next, a structure for adjusting the backlash between each gear will be explained.

In order to adjust the backlash between the small bevel tooth portion 7 of the first bevel gear and the second bevel gear 10, pressing means 16a and 16b are provided at both ends of the first shaft 2a. As shown in FIG. 2, which is a view of the lower end of the first shaft 2a viewed from the direction of arrow A, the pressing means 16b forms a long elongated through hole 17 in the axial direction in the first shaft 2a. The total length L to the through hole 17 is the first axis 2a
A pressing member 18 larger than the outer diameter D of the first shaft 2a is fitted so as to be movable in the axial direction of the first shaft 2a.
from the lower end of the first shaft 2a along the axis of the through hole 1
A cap screw 20 is screwed into a screw hole 19 formed across the center of the holder 7. 21
is a screw hole formed in a direction perpendicular to the axis of the first shaft 2a, and 22 is a set screw for locking the cap screw 20. On the outside of the pressing means 16b, a disc spring 23 for pressing the bearing 3 and a lid 24 are fixed to the first arm 1 via bolts 25. Note that since the pressing means 16a has the same structure as the pressing means 16b, the description thereof will be omitted.

Next, a description will be given of means for adjusting the backlash between the bevel gears 15a and 15b and the upper and lower large bevel teeth portions 6 in the figure. Drive sources 14a and 14b
A spring 27 is interposed between the first arm 1 and the first arm 1 to push the drive sources 14a and 14b toward the first shaft 2a. 26b is screwed in, and its tips are in contact with the drive sources 14a, 14b.

Next, the functions of the joints of such a robot will be explained.

First, the case where the second arm 12 is rotated with respect to the first arm 1 will be explained. In this case, the output shafts of the drive sources 14a and 14b are rotated in the same direction. Then, the first bevel gears 4a and 4b rotate in mutually opposite directions, and as a result, the second bevel gear 10 rotates about the second shaft 2b. In other words, the second arm 12 rotates relative to the first arm 1. In this case, if the rotation speeds of the output shafts of the drive sources 14a and 14b are relatively different, the second bevel gear 1
0 not only rotates around the second axis 2b, but also revolves around the first axis 2a, and the rotation of the second arm 12 with respect to the first arm 1 is accompanied by a turn.

Next, a case will be described in which the second arm 12 is rotated relative to the first arm 1. In this case, the output shafts of the drive sources 14a and 14b are rotated in opposite directions. Then, the first bevel gears 4a and 4b rotate in the same direction, and when the first bevel gears 4a and 4b rotate in the same direction, the second bevel gear 10 cannot rotate in either direction, so the second shaft 2b The second bevel gear 10 and the first bevel gears 4a, 4b rotate together around the first shaft 2a. In other words, the second arm 12 pivots relative to the first arm 1. Also in this case, drive sources 14a and 14b
When the rotation speeds of the output shafts are different from each other, the second bevel gear 10 not only revolves around the first shaft 2a but also rotates around the second shaft 2b. The rotation is accompanied by rotation.

Adjust the backlash between each gear as follows. First, in order to adjust the pressing means 16b, remove the bolt 25, remove the lid 24 and the disc spring 23, loosen the set screw 22, and then rotate the cap screw 20 to the right or left to move the pressing member 18 into the through hole 17. to move it in the axial direction of the first shaft 2a. Then, the pressing member 18 moves the first bevel gear 4b together with the bearing 5, and the backlash between the second bevel gear 10 and the first bevel gear 4b is adjusted. Next, the pressing means 16a is adjusted in the same manner to adjust the backlash between the second bevel gear 10 and the first bevel gear 4a. After this, the drive source 14 is tightened with the cap screws 26a and 26b.
a and 14b to the right in the figure, and bevel gear 1
5a and the large bevel tooth portion 6 of the first bevel gear 4a, and the backlash between the bevel gear 15b and the large bevel tooth portion 6 of the first bevel gear 4b are adjusted.

In this embodiment, all the gears are bevel gears, and the bevel gears mesh with each other, but the invention is not limited to this, and it is also possible to mesh with a face gear and a pinion gear.

H. Effects of the invention As explained above, the robot joint of the invention is constituted by a differential gear mechanism and a plurality of drive sources arranged in parallel near the joint, so that the rotation direction of the plurality of drive sources can be changed. Depending on the selection, the robot's joints can be rotated and rotated in two degrees of freedom. Therefore, the second member is driven by multiple drive sources, and since each drive source is small and has a small output, it is sufficient to use a single drive source for each degree of freedom. The space occupied by the driving source can be made smaller than in the case of the present invention. Further, since the power transmission mechanism is simple, the number of parts is small, and the parts can be sufficiently stored in a small space within the first and second members, and the drive source can be placed near the joint, resulting in good responsiveness.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of a robot joint according to the present invention, and FIG. 2 is a partially detailed view of the first axis viewed from direction A in FIG. DESCRIPTION OF SYMBOLS 1...First arm, 2...Connection shaft, 2a...First shaft, 2b...Second shaft, 4a, 4b...First bevel gear, 10...Second bevel gear, 12...Second arm,
14a, 14b...drive source, 15a, 15b...
Bevel gear.

Claims (1)

[Claims for Utility Model Registration] In a joint of a robot serving as a connecting portion between a first member and a second member constituting an arm of the robot, a first shaft whose both ends are rotatably supported by the first member; , a connecting shaft having one end rotatably connected to a second member and a second shaft having the other end fixed to the center of the first shaft is provided, and the connecting shaft is rotatably connected to both ends of the first shaft. A pair of first gears are provided in the first member, and a second gear that meshes with the pair of first gears is fixed to the second member, and at least one drive source that meshes with each of the first gears is provided within the first member. A robot joint characterized by being arranged side by side.