JPS6248486A - Drive for arm - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an arm drive device for a robot or the like.

(Prior Art) As a conventional example of a robot arm drive device, for example, there is a device described in Japanese Patent Application Laid-Open No. 189785/1983. The schematic configuration of this device is shown in FIG. 5. As shown in the figure, a first arm 52 is rotatably supported on a base 51, and a second arm 53 is rotatably supported at the tip of the first arm 52. is supported by The first arm 52 is driven by a motor 54 attached to the base 51 via a pulley 55, a timing belt 56, and a pulley 57, respectively. Further, the second arm 53 is operated by a pulley 59, a timing belt 60, and a pulley 61 in substantially the same manner as described above, by a motor 58 attached to the first arm 52 substantially coaxially with the rotation axis of the first arm 52.
It is designed to be driven through each. In addition, in the above structure, instead of a timing belt,
A steel belt or cheno may also be used.

On the other hand, as another conventional example of a robot arm drive device, there can be mentioned, for example, a device described in Japanese Patent Application Laid-open No. 58-137581. The schematic configuration of this device is shown in the sixth section.
As shown in the figure, this uses a planar link mechanism, and a drive shaft 63 provided on the first arm 62 is connected to a drive source (
(not shown), which drives the second arm 66 via a pair of links 64 and 65.

(Problems to be Solved by the Invention) However, in the above-mentioned former arm drive device that uses a timing belt, etc., since a flexible member such as a timing belt is interposed in the middle of the power transmission mechanism, its rigidity is insufficient. Therefore, there is a drawback that highly accurate position control cannot be performed.

On the other hand, in a drive device using the latter link mechanism, it is possible to perform highly accurate position control because it has sufficient rigidity, but due to the problem of mutual interference between the links 64 and 65, the There is a drawback that the operating range of the second arm 66 is limited, that is, the second arm 66 cannot be rotated continuously.

This invention was made in order to solve the above-mentioned conventional drawbacks.The purpose of this invention is to have a power transmission mechanism with sufficient rigidity, so that highly accurate position control of the arm can be performed, and the arm can be rotated continuously. The object of the present invention is to provide an arm driving device that allows the arm to be moved.

(Means for Solving the Problems) Therefore, in the arm driving device of the present invention, the first rotary body 8 is rotatably supported with respect to the base 1 and rotationally driven by the drive source 6; The rotation axis A of the first rotary body 8 at a position obliquely displaced from the rotary body 8
a second rotating body 9 that rotates around a rotation axis B that is parallel to;
A connecting rod 1 that connects the first rotating body 8 and the second rotating body 9
0, and both ends 10a, 10 of the connecting rod 10
b indicates both rotational axes A,
It is rotatably mounted at a position equidistant from B and having the same phase θ in the rotational direction, and transmits the rotation of the first rotating body 8 to the second rotating body 9 via the connecting rod 10. The arm 3 is attached to the second rotating body 9.

(Function) As a result of the above, it becomes possible to drive the arm 3 by rotating the first rotating body 8 by the drive source 6 and rotating the connecting rod 10 and the second rotating body 9. In this case, the connecting rod 10 that transmits the driving force from the first rotary body 8 to the second rotary body 9 does not have a limited movement range as in the conventional planar link mechanism, so the arm 3 is It is possible to rotate continuously. In addition, since it does not use a flexible member like a conventional timing belt, the rigidity of the driving force transmission path from the first rotating body 8 to the second rotating body 9 can be ensured, and the high precision of the arm 3 can be ensured. It becomes possible to perform position control.

(Example) Next, a specific example of the arm driving device of the present invention will be described in detail with reference to the drawings.

In FIG. 1, ■ indicates a base, and the base end portion of the first arm 2 is rotatably supported on this base 1. The first arm 2 is a cylindrical member extending obliquely upward from the base 1, and the base end of the second arm 3 is rotatably supported at the distal end of the first arm 2. A hand 4 is supported at the tip of the arm 3. The base 1 includes a driving source 5 for driving the first arm 2.
and a drive source 6 for driving the second arm 3 are provided inside. The output shaft 7 of the drive source 6 for the second arm is led out inside the base end of the first arm 2, and the first rotating body 8 is attached to the tip thereof. On the other hand, inside the tip of the first arm 2, there is a second
A rotating body 9 is arranged, and the second rotating body 9 and the first rotating body 8 are connected by a pair of connecting rods 10, flc, which extend diagonally through the inside of the first arm 2. .

The first rotating body 8 is rotatably supported by a bearing 12 on the inner periphery of the base end of the first arm 2, and the second rotating body 9 is rotatably supported on the inner periphery of the distal end of the first arm 2 by a bearing 13. Rotatably supported. The second rotating body 9 is fixed to the second arm 3, and the rotation of the first rotating body 8 drives the second arm 3 to rotate via the connecting rod 10.11 and the second rotating body 9. It's been like getting. In this case, although not shown, the load in the axial direction of the second arm 3 is mainly supported by the first arm 2, and a large load in the axial direction acts on the connecting rod 10.11. Not that I will.

As shown in FIG. 2, the connecting rods 10 and 11 are divided into upper and lower parts in the middle, and reverse threads 14 and 15 are formed near the divided ends.
．． Oak l-16 is screwed onto 15. In other words, by tightening the NAND 16, a tensile force can be applied to the connecting rod 10.11. Note that the reason for this will be described later.

The connecting rod 10 for the first and second rotating bodies 8.9
．． 11 will be explained based on FIG. 3. First, one end 10a of one connecting rod 10 is rotatably attached to the first rotating body 8, and the other end 10b is rotatably attached to the second rotating body 9. At this time, the rotation of the first rotating body 8 The distance %llL from the shaft to the one end 10a of the connecting rod 10 and the other end 10 of the connecting rod 10 from the rotation axis B of the second rotating body 9
In addition, the phase of the end 10a of the connecting rod with respect to the rotational direction of the first rotating body 8, that is, the rotation angle θ from the virtual reference position 0, and the second rotating body 9 are made equal.
The phase θ of the connecting rod end 10b with respect to the rotation direction of the connecting rod 10b is made equal. Also, both ends 1 of the other connecting rod 11
1a and llb are also attached to both rotating bodies 8.9 at different positions from the above and in the same positional relationship as above. Note that the reason for using the plurality of connecting rods 10.11 as described above is to prevent a dead center from occurring when transmitting rotational force from the first rotating body 8 to the second rotating body 9. If the dead center can be tolerated, a single connecting rod 10 may be used. Also, since using two or three thin connecting rods 10.11 is superior in both rigidity and strength than using one thick connecting rod 10, it is better to use multiple Preferably, connecting rods 10.11 are used.

FIG. 4 shows a structure for attaching the end 10b of the connecting rod 10 to the second rotating body 9. As shown in the figure, the end 10b of the connecting rod 10
b is attached to the second rotating body 9 via a self-aligning ball bearing 17 to prevent an excessive moment from acting on the connecting rod 10. In the same figure, 18 is a bearing nut, 19 is a ball, and 20.2
1 indicates the inner and outer rings of the bearing, respectively. Further, the other end 10a of the connecting rod 10 and both ends 11a and Ilb of the other connecting rods 11 have the same structure as above, and the rotating body 10.
11, but its illustration is omitted here.

The arm driving device described above operates as follows.

First, when driving the second arm 3, the output shaft 7 of the drive source 6
The first rotating body 8 is rotated by. Then, the connecting rod l0111 is on its one end side 10a, and on the lla side the first
The other end side 10b, llb
Then, the second rotary body 9 rotates around the rotation axis B, thereby causing the second rotary body 9 to rotate and the second arm 3 to be driven. On the other hand, the first arm 2 is driven by a drive source 5.

In the arm driving device described above, the pair of rotating bodies 8.9 and the connecting rod 10.1 connecting the two bodies are connected to each other.
1 constitutes a driving force transmission mechanism, but since this mechanism does not have a limited range of motion like a conventional planar link mechanism, the range of motion of arm 3 is also limited. First, it is possible to rotate the arm 3 continuously.

Furthermore, since a flexible member such as a tamming belt is not used as in the conventional case, the rigidity of the entire mechanism can be ensured, and the position of the arm can be controlled with high precision.

By the way, by dividing the connecting rod 10.11 in the middle and tightening the nut 16, the connecting rod 10.1 can be separated.
In the case where tensile force is applied to the connecting rod 10
．． An axial load, that is, a thrust load, is applied to each bearing 17 attached to the bearing 11 due to the above-mentioned tensile force. In other words, each of the above bearings 1
Preload is applied to 7...17, and the contact area between the lower ball 19 of the bearing 17 and the inner and outer rings 20.2I in FIG. 4 is increased, that is, the rate of increase in the amount of deformation is small. It becomes. On the other hand, when the second arm 3 is driven, a tensile force mainly acts on the connecting rods 10 and II, but even if this tensile force fluctuates, the bearing 17 remains in the above state. The amount of deformation of the inner ring 20 is small. In other words, by applying a tensile force to the connecting rods 10 and 11, the rigidity of the bearing 17 and, by extension, the rigidity of the driving force transmission mechanism can be improved, and the accuracy of position control of the arm can be further improved. In addition, since the bearing 17 is preloaded as described above and the bearing 17 is used with the pawl 19 in contact with the inner and outer rings 20 and 21, the gap in the bearing 17 is reduced, thereby reducing backlash. It becomes possible to do so.

Furthermore, in the above-mentioned device, since the driving force transmission mechanism is disposed inside the first arm 2, the external structure is simple. Although the above-mentioned drive device can of course be used when a reduction gear is used, it is particularly suitable for driving the arm by a direct drive method because it has sufficient rigidity and high position control accuracy.

In the above embodiment, the case where the 27th arm 3 is driven has been explained, but of course this driving device can also be used to drive the third arm or other arms.

(Effects of the Invention) As described above, the arm drive device of the present invention constitutes a driving force transmission mechanism by a pair of rotating bodies and a connecting rod that connects the two, and therefore, it does not require a conventional planar link mechanism. The range of motion is not limited as in the case of actual use, and the arm can be rotated continuously. In addition, since it does not use flexible members such as timing belts as in the past, the rigidity of the entire mechanism can be ensured, making it possible to perform highly accurate position control of the arm.

[Brief explanation of the drawing]

Fig. 1 is an overall explanatory diagram of one embodiment of the arm driving device of the present invention, Fig. 2 is a sectional view showing the divided constituent parts of the connecting rod, and Fig. 3 is an explanation for explaining the arrangement of the connecting rod. Figure, 4th
The figure is a vertical cross-sectional view showing the attachment structure of the connecting rod to the rotating body.
FIG. 6 is an explanatory diagram of a conventional example. I- Base, 3 Second arm, 6 Drive source, 8 First rotating body, 9 Second rotating body, 10.1
1... Connecting rod, lOa, 10b, 11a, l
lb... End of the connecting rod, A... Rotating shaft of the first rotating body, B... Rotating shaft of the second rotating body. Figure 8

Claims (1)

[Claims] 1. A first rotating body (8) rotatably supported on the base (1) and rotationally driven by a drive source (6)
and a second rotating body (9) rotating around a rotating axis (B) parallel to the rotating axis (A) of the first rotating body (8) at a position obliquely displaced from the first rotating body (8). ) and the first
A connecting rod (
10), and both ends (10a
) (10b) for both rotating bodies (8) and (9), respectively,
It is rotatably mounted at a position equidistant (L) away from both the rotational shafts (A) and (B) and in the same phase (θ) in the rotational direction to control the rotation of the first rotational body (8). The above connecting rod (10)
1. An arm driving device characterized in that the arm is configured to transmit information to a second rotating body (9) via the arm, and an arm (3) is attached to the second rotating body (9).