JPH01153286A - Industrial robot - Google Patents

Abstract

PURPOSE: To enhance the rigidity of arm-connecting parts and sufficiently ensure the operating range of arms by connecting a lower arm member and an auxiliary arm member to an upper arm member on a line provided with a specified amount relative to the axis of the upper arm member. CONSTITUTION: A connecting position of a lower arm member 7, an auxiliary arm member 8 provided parallel to the lower arm member 7, and an upper arm member 10, on one end of which a wrist part is provided, is set below outside the side part of the upper arm member 10. At the connecting position, the members (7 and 10), (8 and 10) are respectively connected to each other by pin shafts 19 passing through both the members (7 and 10), (8 and 10). By connecting the arm members in this way, the rigidity of the connecting parts can be increased, and the operating range and the speed range of the arms can be optimized under the conditions of the same arm length and the same angle of rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an industrial robot, and particularly to a parallel link type robot.

[Conventional technology]

There are various types of robots, especially industrial robots, such as those of the orthogonal coordinate type and those of the articulated type. There are also various types of articulated robots depending on the drive method. (US Pat. No. 3,630,389, US Pat. No. 4,076,131, US Pat. No. 4,199,294).

In this type of robot, the lower arm member and the upper arm member constituting the robot arm are located at the center (axis) above the (second arm) of each side for the wrist drive component provided inside the upper arm member. ) are rotatably connected by a pin shaft provided on a line. However, in robots that handle high loads, external loads, self-weight, inertial force, impact load, torsional load, etc. act on this pin shaft joint during actual work, so it is necessary to strengthen the structure of this joint. Thus, in order to strengthen the structure of the joint, it is necessary to increase the wall thickness of this part and the shaft diameter of the pin.

On the other hand, in recent years, robots are required to work at high speeds, and from the perspective of improving accuracy, including offline teaching, there is a need for improved repeatability in positioning, and for highly rigid structures that do not generate vibrations due to positioning problems. However, when the structure of the joint is strengthened as described above, the rigidity becomes good, but the driving force increases as the weight increases, which is not good from the viewpoint of energy saving. In addition, optimizing the arm operating range (including position) under the same arm length and arm rotation angle conditions is important in terms of workability, and this solution was strongly desired. .

[Problem to be solved by the invention]

The above conventional technology does not take into consideration the working range of the robot arm, and cannot optimize the working range of the arm under the same arm length and same rotation angle conditions, and also has problems with the rigidity of the arm joint. there were.

An object of the present invention is to provide an industrial robot that can secure a sufficient working range of the arm while increasing the rigidity of the arm joint.

[Means to solve the problem]

The above object is to provide an industrial robot including a lower arm member, an auxiliary arm member provided in parallel to the lower arm member, and an upper arm member having one end at the wrist. Positioning the member and the auxiliary arm member relative to the axis of the upper arm member [action] Shifting the connection between the lower arm member and the lower arm member and the auxiliary arm member by an offset amount from the center (axis m) of the upper arm member By connecting them at the same position, the distance between the rotation center and the arm tip position can be changed, and the work space and work speed distribution can be optimized.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a robot equipped with an embodiment of the apparatus of the present invention, and in this figure, the robot is shown as having a parallel link type robot arm. 1 is a fixed base, 2 is a revolving body on the fixed base, 3 is a support bracket provided on the revolving body, and 4 is a robot arm installed on the support bracket 3. The robot arm 4 is connected to a driving means 5 comprising a motor 5A, a screw shaft 5B rotated by the motor, and a ball portion 5C engaged with the screw shaft 5B. This drive means 5 is swingably supported by a bracket 6 on the revolving body 2 in parallel to the drawing of FIG.

The robot arm 4 described above includes a lower arm member 7, an auxiliary arm member 8 parallel to this, a connecting member 9 that also functions as a lever member orthogonal to these arms 7 and 8, and an upper arm parallel to this. It is composed of a member 10.

At one end of the upper arm member 10, a wrist portion 11 is rotated, bent,
Three drive motors 12 for swinging motion are installed, and a power transmission cylinder 13 for transmitting the power of each drive motor 12 to the wrist portion 11 passes through the inside of the upper arm member 10.

The lower arm member 7, the auxiliary arm member 8, and the upper arm member 10 are coupled on a line having an offset amount H with respect to the axis 10A of the upper member 10. As a result, the distance between the one-rotation axis 19 and the arm tip 11 (wrist) can be determined by appropriately adopting the offset amount H to achieve the required optimal work range and speed range under the same arm length and the same rotation angle range. This makes it possible to achieve this goal. (In the case of H=2 compared to the case of H=O, the distance R from the rotation axis 19 to the tip 11 (wrist) and the rotation angle position change) For convenience of explanation, the lower arm member 7 and the upper arm member A detailed structural example of the connecting portion with 10 will be explained using FIGS. 2 and 3.

A coupling bracket 14 is coupled to both sides of the upper arm member 1o by welding or the like. These joining brackets 1
4 is provided with a boss 16 that holds a bearing 15.

These bosses 16 are connected by a cylinder 17.

Between this cylindrical body 17 and the upper arm member 10.

A belly plate member 18 is provided. As a result, the joint portion of the upper arm member 10 is formed into a box-shaped structure, and the torsional rigidity of this portion can be increased. The coupling bracket 14 of the upper arm member 10 and the coupling bracket 7A of the upper arm member 7
and are rotatably coupled by a pin shaft 19 passing through them.

This coupling structure is similarly constructed in the coupling between the upper arm member 7 and the auxiliary arm member 8 shown in FIG. Although a box-shaped structure is shown here, a gate-shaped structure is also possible, although the conditions are slightly different.

As explained above, one aspect of the present invention is to set the joint position of the lower arm member 7, the auxiliary arm member 8, and the upper arm member 10 to the lower side where the side part of the upper arm member 10 is removed, and to penetrate both members at this position. Since the arms can be connected by the pin shaft 19, the rigidity of this joint can be increased, and it is also possible to optimize the arm operating range and speed range as described above.

Furthermore, compared to the conventional structure in which the joint part with the lower arm member 10 is formed in the chain part of the upper arm member 10, the rising length Y of the joint bracket 7A of the lower arm member 7 can be made smaller. The wall thickness for an applied load of 7A can be made smaller than that of the conventional one.

As a result, it is possible to maintain high rigidity of this joint and reduce the weight. Along with this, it is possible to achieve higher precision and higher rigidity, which makes it possible to apply advanced technology to off-line teaching tubes.

Note that the above-described embodiment includes the lower arm member 7 and the auxiliary arm member 8.
The lower arm member 7 and the auxiliary arm member 10 are connected to independent coupling brackets 14, but as shown in FIG. 4, the lower arm member 7 and the auxiliary arm member It is also possible to combine 8. In this case, the ease of assembling the joint will be improved. Further, the connection of the coupling brackets 14.20 to the upper arm member 10 is not limited to welding, but bolting is also possible, and these coupling brackets 14.20 may be integrally formed by casting. Furthermore, it goes without saying that the type of robot arm is not limited to the parallel link type described above. Furthermore, if the torsional load is not large, the belly plate member 18 may be omitted.

〔Effect of the invention〕

According to the present invention, it is possible to determine the optimal arm movement range and work speed range.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an example of a robot equipped with an embodiment of the device of the present invention, FIG. 2 is a longitudinal sectional front view of the device of the present invention shown in FIG. FIG. 4 is a front view of an example of a robot 4 equipped with another embodiment of the device of the present invention. DESCRIPTION OF SYMBOLS 1... Fixed base, 2... Swivel body, 4... Robot arm, 7... Lower arm member, 7A... Connection bracket, 8... Auxiliary arm member, 9... Communication member , 10...
Upper arm member, 14... Connection bracket, 15... Bearing, 16... Boss, 17... Cylindrical body, 18... Belly plate member, 19... Pin shaft, 20... Connection bracket.

Claims (1)

[Claims] 1. An industrial robot comprising a lower arm member, an auxiliary arm member provided parallel to the lower arm member, and an upper arm member having a wrist portion at one end, the upper arm member, the lower arm member, and An industrial robot characterized in that the auxiliary arm member is connected to the upper arm member along a line having a predetermined distance from the axis of the upper arm member.