JPS63180491A - Balancer mechanism of vertical multi-joint type robot - 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 a balancer mechanism for a vertically articulated robot having an arm that pivots about a horizontal pivot axis.

[Conventional technology and problems]

Conventionally, a coil spring has been used as a balancer mechanism for a vertical articulated robot having an arm that rotates around a horizontal rotation axis, or a pneumatic cylinder mechanism that supplies pressurized air from the outside has been used.

However, in the former case, in order to generate a large supporting force, a very large spring is required, which lacks compactness, and it is not easy to design a spring that has an appropriate spring constant and supporting force. The latter requires an external pressure source and requires the installation of pressure air supply piping, etc., making the work area complicated, and on the other hand, it is not easy to control the supply air pressure appropriately.

SUMMARY OF THE INVENTION Therefore, in order to solve these problems, it is an object of the present invention to provide a balancer mechanism for a vertically articulated robot that has a compact and simple structure that provides a large supporting force.

[Means for solving problems]

In view of the above object of the invention, the present invention provides a balancer mechanism for a vertical multi-joint robot that supports an arm that rotates around a horizontal rotation axis according to the rotation angle position of the arm, wherein one end is connected to one end of the arm. is connected to a support part that supports it so as to be able to rotate about the horizontal rotation axis, and the other end is connected to the other end of the arm, and as the arm tilts, the gas in the closed space is compressed to cause the arm to A balancer mechanism for a vertically articulated robot is provided, characterized in that it is equipped with a pneumatic cylinder mechanism that generates a supporting action.

[For production]

According to the above-mentioned gas pressure cylinder mechanism, as the arm of the robot turns and tilts about the horizontal axis, the gas in the closed space inside the cylinder is compressed, and the arm is supported by the reaction force. The greater the inclination of the arm, the greater the compression rate of the gas, and the greater the supporting force.

〔Example〕

The present invention will be described in more detail below based on embodiments shown in the accompanying drawings. FIG. 1 is a diagram of a pneumatic cylinder mechanism according to the present invention, FIG. 2 is a diagram of a vertical articulated robot equipped with a balancer mechanism, and FIG. 3 is an auxiliary diagram for explaining the balancer mechanism.

First, referring to FIG. 2, a swinging trunk 12 capable of swinging around a vertical axis θ is attached to the upper part of the base part 10, and a first arm 16 is supported by a support part 14 fixed to the swinging trunk 12. The lower end portion thereof is supported so as to be pivotable about a horizontal axis W.

A second arm 42 that can pivot about another horizontal axis U is attached to the upper end of this first arm, and the tip of this second arm 42 can pivot about three axes γ, β, and α. A wrist portion 44 is attached thereto. Various tools are attached to the tip of this wrist portion 44 to perform robot work.
, a large load based on the weight and work load of the second arm 42 and wrist portion 44 is applied. To adjust the load, a balancer mechanism 18 has one end attached to the upper part of the support part 14 so as to be rotatable about the horizontal axis 24, and the other end attached to the tip of the first arm 16 about the horizontal axis 26. It is rotatably mounted. Conventionally, for example, a coil spring is built in the container 20, and the rod 22
As the container 20 and the container 20 move relative to each other, the spring is compressed or expanded to generate a supporting force. In the present invention, the piston 22
The balancer mechanism 18 generates a supporting force as the cylinder 20 and the cylinder 20 move relative to each other.

Referring to FIG. 3, the operation of the balancer mechanism 18 in accordance with the rotational inclination angle δ of the first arm 16 will be described.

A position where the first arm 16 is inclined by an angle δ from the vertical position about the central axis W is indicated by 16'. The distance between the central axis W and the aforementioned central axis 24 is indicated by b, and the minimum length of the balancer mechanism 18 in the vertical position is indicated by a. 1st
The arm 16 has a constant length C, c''a+b, regardless of its turning angle position δ.On the other hand, the length a4 of the balancer mechanism 18 changes depending on its position.

a6 = 5 bc case thea o1) a6 ≧
a There is. In this way, in the balancer mechanism 18, the first arm 16 rotates and tilts, and its length aδ is extended, and as a result, due to the action of the cylinder/piston mechanism shown in FIG. 1, which will be described later, or the conventional spring mechanism, the above-mentioned The position of the first arm 16 corresponding to the horizontal axis 26 is set as the point of action, and a balancer torque Tδ is generated in the direction of returning the first arm 16 to its original vertical position about the central axis W. If the force acting in the longitudinal direction of the balancer mechanism 1 which is generated on the balancer mechanism 18- at this time is F, then T6 =Fδ・C−cos (δ+φ)sinφ=
(Ccos δ-b) / a Jcosφ=C3t
It becomes n δ/a 6 .

Here, the configuration of the balancer mechanism 18 will be explained with reference to FIG. A piston 22 is inserted into the cylinder 20, and a piston head 40 is attached to the upper end of the piston 22 so as to be slidable within the cylinder 20. The inside of the cylinder 20 is divided into an upper space 30 and a lower space 28 by the piston head 40, and the outside is connected via a muffler 38 that also serves as a filter, a check valve 34, and a muffler 36 that also serves as a filter. communicates with the atmosphere. Reference numeral 32 indicates a pressure gauge, and the cylinder 20 and piston 22 are sealed by any suitable known technique. With the above configuration, when the cylinder 20 and the piston 22 move relative to each other, such as when the first arm 16 (see FIGS. 1 and 2) is tilted, the cylinder 20 and the piston 22 move inside the cylinder 20. receives a reaction force due to the compression of the air in the lower space 28 of.

That is, the position of the piston head 40 shown by the solid line in FIG. 1 corresponds to the case where the first arm 16 is in the vertical position, and in this state, the upper space 30 is at atmospheric pressure,
The lower space 28 is also set to atmospheric pressure, for example. When the first arm 16 is tilted and the piston head 40 moves relative to the cylinder 20 and is lowered to the position 40' shown by the two-dot chain line, the inside of the upper space 30 is in communication with the outside air and the initial atmospheric pressure is On the other hand, the check valve 3 remains in the lower space 28.
Due to the action of 4, the internal air is compressed because it does not communicate with the outside. The pressure (gauge pressure) p generated at this time is expressed by the following equation, assuming that the polytropic index of air is n.

p = (Vo Pa Vo Ao・1)) ”・(po+1)
1 where, o: Volume of the air in the initial lower space, po: Initial pressure of the air in the lower space (atmospheric pressure), Ao:
Effective cross-sectional area of the piston head or cylinder, It: Piston movement amount (=a a a ). Therefore, the aforementioned balancer torque T is calculated by the following formula (%) (%) In this embodiment, the initial pressure of the air in the lower space 28 is set to atmospheric pressure, but this is because if the air is This is to enable air to be automatically replenished via the check valve 34 and return to atmospheric pressure if the pressure drops below atmospheric pressure due to leakage from the cylinder to the outside. Therefore, if leakage is excluded, the air pressure need not be limited to atmospheric pressure, and other gases may also be used. Furthermore, contrary to this embodiment, it is also possible to arrange the piston 22 upward and the cylinder 20 downward.

〔Effect of the invention〕

In the case of the cylinder-piston mechanism that utilizes the compression action according to the present invention, it is possible to increase the pressure even at a shallow level of the initial setting pressure depending on the compression ratio, so in the case of using the tension action, it is possible to increase the pressure up to the initial setting pressure at most. It is advantageous to obtain a large balance force compared to the fact that only 1 force can be generated. Furthermore, since the cross-sectional area and initial pressure can be set arbitrarily, the balance force can be continuously selected, which facilitates the design. Furthermore, since the compression ratio can be increased, a compact balancer mechanism capable of generating a large balance force can be obtained. In addition, as the inclination angle of the first arm increases, the required balance force becomes larger, but the change in compression ratio as the piston moves becomes larger, making it more effective than a spring mechanism. It can generate balance force.

[Brief explanation of the drawing]

Fig. 1 is a diagram of the pneumatic cylinder mechanism according to the present invention, Fig. 2 is a diagram of a vertically articulated robot equipped with a balancer mechanism, and Fig. 3 is a diagram of a vertical articulated robot equipped with a balancer mechanism.
The figure is an auxiliary diagram to explain the balancer mechanism. 10...Base part, 12...Swivel body, 14...
- Support part, 16... First arm, 18... Balancer mechanism, 20... Cylinder, 22... Piston, 28... Lower space, 30... Upper space,
34... Check valve, 36. 38... Silencer (filter), W... Rotation axis of first arm, δ... Rotation angle of first arm.

Claims (1)

[Scope of Claims] 1. A balancer mechanism for a vertically articulated robot that supports an arm that pivots about a horizontal pivot axis according to the pivot angle position of the arm, the balance mechanism having one end that supports one end of the arm as the The arm is connected to a support part that supports the arm so as to be pivotable around a horizontal pivot axis, and the other end thereof is connected to the other end of the arm, and as the arm tilts, the gas in the closed space is compressed to support the arm. A balancer mechanism for a vertically articulated robot characterized by being equipped with a pneumatic cylinder mechanism that generates. 2. The balancer mechanism for a vertically articulated robot according to claim 1, wherein the gas is air and the pressure is atmospheric when the closed space has a maximum volume.