JPH03213280A - Industrial robot - Google Patents

Abstract

PURPOSE:To enable a robot to recede so largely or turn upward so extensively, by constituting the turning central axis of a first joint part with a vertical axis, the turning central axis with a second joint part, respectively, and making up the tip of a member at the tip side of the second joint part so as not to exist on the turning central axis of this second joint apart. CONSTITUTION:When both first and second joint parts D, A are turned round, a turning central axis O1 of the first joint part D is composed of a vertical axis, and a turning central axis Oa of the second joint part A is composed of a tilted axis, not vertical or horizontal one, and these joint parts D, A rotates with these turning central axes O1, Oa. Consequently, at time of rotation, members at both base end sides of these joint parts D, A, namely, members at the base end side of a member (lower arm) 5 at the tip side of the joint part A and the joint part D will not interfere with each other so that they can secure an extensive operating range. In brief, a robot is largely retracted or turned round upward so extensively.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to industrial robots, and particularly to industrial robots equipped with joints.

(Prior art) In recent years, three-dimensional structures have been welded in industry due to their wide range of motion and high degree of freedom of movement.

Articulated robots are often used mainly in fields that require complex movements such as assembly or painting.

These articulated robots can be roughly divided into horizontal articulated robots in which the degrees of freedom of the joints are primarily horizontal, and vertical articulated robots in which the degrees of freedom of the joints are primarily vertical. It is roughly divided into types.

Generally, in a vertical articulated robot, as shown in FIG. 8, a rotor trunk part 2 is rotatable in the direction indicated by an arrow R' with respect to a base part l around a central rotation axis 3. It is arranged. The rotor trunk portion 2 includes a drive motor M each having two concentric drive shafts 4A and 4B.
is installed. The one drive shaft 4A has an arrow Q
The lower end of the link member 5A is fixed so as to be rotatable in the direction shown by °, and a link member 5B (see broken line) is fixed to the other drive shaft 4B so as to be rotatable in the direction shown by arrow P'. The left end is fixed, and a link member 5C is rotatably supported on the right end of the link member 5B. The upper end portions of the link member 5A and the link member 5C are rotatably supported at separate positions on the upper arm portion 6. A distal end portion 6B is attached to the distal end portion of the upper arm portion 6 and is rotatable in the direction indicated by an arrow W with respect to the base portion 6A side. A wrist portion 7 is attached rotatably in the direction shown by arrow V'.

The upper arm portion 6 is rotated by the rotation of the link member 5A while the link member 5B is fixed.
Alternatively, it operates by rotating the link member 5B while the link member 5A remains fixed. For example, when the link member 5B and the link member 5A rotate clockwise to the limit, the right part in FIG. It is possible to retreat to the position shown in (move to the right in the figure).

(Problem to be Solved by the Invention) However, in the case of the vertical articulated robot having the above configuration, the link members 5A and 5B supporting the upper arm portion 6
, 5C interfere with each other and cannot be rotated beyond a certain angle, resulting in the inconvenience that the upper arm portion 6 cannot be moved largely backward or rotated significantly upward.

Further, as a vertically articulated robot that can make the above-mentioned upper arm portion 6 move largely backward or rotate greatly upward, there is a robot having a configuration as shown in FIG. This type of vertically articulated robot refers to the rotatable joints between supporting members and supported members, such as the base portion 1 and the rotor trunk portion 2, the lower arm portion 5 and the upper arm portion 6, etc. ), there is no interference between the support member, which is the member at the proximal end of the joint, and the supported member, which is the member at the distal end of the joint, during rotation. It does not have the problem of a limited range of motion like the robot shown.

However, in the case of the vertical articulated robot shown in FIG. 9, when the lower arm 5 is rotated, the upper arm 6 also rotates together with the lower arm 5.
The load torque (rotational moment) of the drive motor M that rotates becomes extremely large. In particular, when it comes to heavy-load robots (robots that can handle heavy objects), when the lower arm 5 is in the state shown in FIG. The load torque of the motor M becomes extremely large, and therefore, it is not practical to adopt such a structure for a heavy-load robot.

The present invention has been made in view of the above-mentioned current situation, and an object of the present invention is to provide an industrial robot that does not have the above-mentioned problems.

(Means for Solving the Problems) An industrial robot according to the present invention is an industrial robot that is provided with rotatable joints between members and whose base portion is installed on a substantially horizontal installation surface. The central axis of rotation of the joint is a vertical axis, and the central axis of rotation of the second joint is an inclined axis that is neither vertical nor horizontal, and the member on the distal side of the second joint The industrial robot configured as described above has the following features:
When the first and second joints rotate, the central axis of rotation of the first joint is a vertical axis, and the central axis of rotation of the second joint is an inclined axis that is neither vertical nor horizontal. Since each joint rotates around these rotational axes, when rotating, the members at both ends of each joint, that is, the member at the distal end of the joint (supported member), and the joint Since the member (supporting member) at the proximal end of the part does not interfere with each other, a wider range of motion can be obtained. That is, it is possible to make a large backward movement or to make a large upward rotation.

Also, the magnitude of the rotation moment around the rotation center axis is [
It is determined by (distance from the load position to the rotational center axis) x (component force of the load in the direction of the rotational center axis) J. The central axis of rotation of the second joint is a vertical axis, and the central axis of rotation of the second joint is an inclined axis that is not vertical or horizontal. Since the component force in the direction is very small, a large load torque is not required to rotate the supported member compared to the case of the robot joint shown in FIG. Specifically, in the case of the conventional robot shown in FIG.
), the rotational moment T2'' around the rotational axis acting on the second joint A changes the load weight to W,
If the length from the second joint to the load is l, and the inclination from the vertical axis (in this case the Z axis) is θ2, then Tz = W −1, −5tn θ2.

On the other hand, in the case of the robot according to the present invention, as shown in FIG. 7(a), the rotation moment T2 around the rotation axis acting on the second joint A is
, the length from the second joint to the load is 2, the inclination from the vertical axis (Z-axis in the case of joints) is θ2, and the rotation center axis of the second joint is 0. If the inclination from the horizontal axis (in this case, the
−5in θ2”, so T,=W −1−cos
”θ,・sin θ2.

Therefore, the maximum value of the rotation moment around the rotation axis of the second joint of both (Tz °), , (Tz),
□ are as shown below, and it can be seen that in the case of the robot according to the present invention, the larger θ is, the smaller the rotational moment is required.

(Tz °), □ = W-2 (Tz) = W-Z 'cos'' θ3 Furthermore, the rotation center axes of the first and second joints are connected to the members on both sides of the joints (supporting member and covered member). Since the axis of the support member (supporting member) is perpendicular or has an inclined angle and does not bend as sharply as in the past, if a hollow part is formed in this joint, the members on both sides of the joint will have a continuous and gentle bend. Even if a cable hose for piping, wiring, etc. (in this specification, piping, wiring, etc. is referred to as a cable hose) is rotatably fixed to the above member, the cable hose is The occurrence of twisting is small, and the reliability of these internal piping and wiring is greatly improved.

Therefore, piping and wiring that were conventionally exposed to the outside at the joint can be stored inside, and as a result,
Damage to these pipes and the like due to contact with the workpiece can be prevented, and wiring and the like will not be damaged by sparks or organic solvents from work near the hand portion.

(Example) Hereinafter, an example of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a skeleton diagram showing the configuration of an industrial robot according to an embodiment of the present invention.

In FIG. 1, 1 is a base part, 2 is a rotor trunk part, 5 is a lower arm part, 6 is an upper arm part, and 7 is a wrist part. A joint portion (a joint portion constituting a second joint portion in this embodiment) is formed between the rotor trunk portion 2 and the lower arm 5, and the rotation center axis 0 is connected to this joint portion.
is an inclined axis that is not vertical or horizontal, that is, the rotation center axis 03 is configured to have an inclination angle θ1 with respect to the horizontal plane. As a result, the tip of the lower arm 5 is configured such that it does not lie on the rotation center axis O1.

In the case of this embodiment, the above configuration is the rotor trunk section 2.
and the virtual contact surface lO of the lower arm portion 5 are aligned with the respective axes 0□, 0. The angle of inclination θ4 made with respect to the lower arm 5 is formed to be equal to the angle of inclination θ3 described above by rotatably connecting the rotor trunk portion 2 and the lower arm portion 5.

In this embodiment, a cross roller bearing 11 is disposed between the rotor trunk section 2 and the lower arm section 5 to ensure smooth rotation between them.

Further, a joint B between the lower arm section 5 and the upper arm section 6 (joint section constituting the third joint section in this embodiment) is also constructed in the same manner as the joint section A.

The central axis of rotation of the third joint is 0. (the angle of inclination of the rotation axis 0 with respect to the horizontal plane is θb) is constituted by an inclined axis that is not parallel or perpendicular to the lower arm 5, which is the member on the distal end side, and in this embodiment, the above-mentioned joint The rotational center axis 03 of the part A and the rotational center axis Ob of the above-mentioned joint part B are configured to be located on the same plane (the plane of the paper in FIG. 1). In the state shown in Figure 1), the axis 0° and the axis 0.
, 0b can be parallel.

In addition, in the joint D formed by the connecting part of the base part 1 and the rotor trunk part 2 (the joint part constituting the first joint part in this embodiment), their axes (L, 02 and the rotation center axis 04 are both disposed on vertical axes and are configured to rotate in a horizontal plane.

The base part 1 has a drive motor (sabot motor).
M+ is arranged and the gear 1 is attached to this drive shaft 14A.
4a is a gear 14 formed at the base of the rotor trunk portion 2;
b, and by the rotation of the drive motor M, the rotor trunk portion 2 is aligned with the rotation center axis O with respect to the fixed base portion 1.
It is configured to rotate in the direction shown by arrow R around d.

A drive motor (servo motor) M2 is also disposed in the rotor trunk section 2, and a gear 14c attached to the drive shaft 14B is a gear 1 formed at the base of the lower arm 5.
4d, and the rotation of the drive motor M2 rotates the lower arm 5 with respect to the rotor trunk portion 2 in the direction indicated by the arrow P around the rotation center axis O1. Therefore, when rotating, the tip of the lower arm 5 is rotated at the center axis of rotation as described above.
Therefore, it does not exist above. That is, between the rotor trunk portion 2 and the lower arm 5 forming the joint portion A, the intersection angle of the two axes 01 and 0□ of the lower arm 5, which is the supported portion, and the rotor trunk portion 2, which is the supporting portion, is as follows. This will change as the joint A rotates.

Further, a drive motor (servo motor) M3 is also disposed on the lower arm 5, and a gear 14e attached to the drive shaft 14C is a gear 14f formed at the base of the upper arm 6.
The rotation of the drive motor M3 causes the upper arm 6 to rotate relative to the lower arm 5 in the direction indicated by the arrow Q about the rotation center axis Ob. Therefore, during rotation, the tip of the upper arm 6 does not lie on the rotation center axis Ob. That is, between the lower arm 5 and the upper arm 6 forming the joint part B, the intersection angle between the two axes O, OS of the upper arm 6, which is the supported part, and the lower arm 5, which is the supporting part, The sound changes as part B rotates.

Thus, the present industrial robot configured as described above operates as follows.

That is, from the state shown in FIG.
. In order to correct (correct) the rotation of each arm in the direction of the arrow R caused by the rotation of the drive motor M1.
When the rotor trunk section 2 is rotated at the joints with respect to the base section 1 by driving the rotor trunk section 2, it can be freely moved forward and backward.

More specifically, various motions of this robot were simulated, ranging from the motions of a conventional vertical articulated robot as shown in FIGS.
This robot can perform operations similar to those of conventional horizontal articulated robots as shown in Figures (a) to (d), or a combination of these operations. That is,
Due to the above configuration, when this robot determines the position of the tip of one wrist, the upper arm, the lower arm,
It is possible to perform any of several combinations of the operations of the rotor trunk portion and the like.

Therefore, in a manufacturing line or an assembly line in which a vertical articulated robot and a plurality of types of horizontal articulated robots have conventionally been arranged and operated, the industrial robot of the type according to the present invention is not necessarily the same as the above-mentioned conventional robot. or even more complex tasks.

In addition, in the case of this industrial robot, in the conventional vertical articulated robot shown in FIG. 9, when the rotation angle of the supported part with respect to the supporting part is 90 degrees (see Fig. 1θ), That is, when the supported part becomes horizontal with respect to the supporting part, the maximum moment is generated at this joint part. Expressing this moment in a formula, the maximum moment T'□, where W is the weight on the tip side and 2 is the distance to the center of gravity, is T',,1I=W-1t-5in 90°=W-4
! becomes.

On the other hand, the rotation angle of the supported part with respect to the supporting part is 90
For example, in the case of the robot according to this embodiment, the inclination angles of the joints are θ, θ.

etc. is assumed to be 45°, then T,, x = W −f ・cos” 45 ° ・si
n90'=0.5・W-1, the maximum rotational moment T, which acts on each joint is halved, and the load torque of the drive motor is therefore halved, making it suitable as a robot for heavy loads. Can adapt.

Furthermore, in the case of the robot according to this embodiment, when the rotation angle is 180 degrees (when the supported part has rotated 180 degrees with respect to the support part from the state shown in FIG. 1), that is, when the rotation angle is 180 degrees, In the robot with the configuration, the rotational moment T is rT=W
-113, which is the largest when the supported part assumes a horizontal position, the rotational moment T of each joint described above can be reduced to zero. Therefore, when the joint is in this state,
Since the joints mechanically bear the load, the load on the drive motors that drive the joints becomes zero, which saves power consumption and eliminates unnecessary loads on the drive motors. become.

In addition, this industrial robot, as shown in Figure 2,
Pneumatic piping to the working hand attached to the wrist 7 (see Figure 1) or wiring for the drive motor can be easily routed through the joints A and B. Part A
, B also rotate, as described above, the rotation center axes o, , Oh of the joints are at an inclination angle θ8. θb, and the rotational center axis 04 of the joint part is configured as a vertical axis, so that these piping and wiring are not extremely bent or twisted, especially in this embodiment. As shown in FIG. 2, a cylindrical cable guide 8 is disposed at each joint so as to be rotatable with respect to the joint, so that almost no torsion occurs. In the case of this configuration, the piping, wiring, etc. are only bent due to the rotation between the supporting part and the supported part, and the bending also has a gentle curvature as shown in Figure 2. It has very high durability against repeated bending, and also has a protective effect against external damage.

By the way, in the above embodiment, the rotation center axes of each joint are formed on the same plane, that is, the inclined surfaces between the supported part and the supported part in each joint are formed in different directions of inclination by 180 degrees. As illustrated in FIG.
By changing the angle for each joint such as 0°, the above-mentioned figures 3 (a) to 4 (a) -
It is also possible to perform a more complex operation than that shown in (d).

In addition, as shown in FIG. 6, the second joint A and the third
If a rotatable fourth joint E is provided on the lower arm 5 between the joints B, the entire movement becomes more flexible, and in particular, the rotation center axis of the fourth joint E is 0.
If , are configured on the axis OS of the lower arm 5 or on an axis parallel thereto, even more flexible operation becomes possible. That is, even if the tip position and posture of the robot's hand section are determined by rotating only the joint section E, the bending state of the joint section A between the lower arm 5 and the upper arm 6 is determined. With a line connecting the lower end point of the lower arm 5 (rotational center axis of the joint part with the rotor trunk part) and the upper end point of the upper arm 6 (the rotary center axis of the joint part with the hand part) as an axis, The lower arm 5 and the upper arm 6 can be freely rotated as a unit to assume various postures, and as a result, more flexible movement is possible.

(Effects of the Invention) Since the industrial robot according to the present invention is configured and operates as described above, it can obtain the following effects.

(a) Since one industrial robot can make large backward movements or large upward rotations as mentioned above, conventionally, in order to perform a series of tasks, multiple industrial robots matching each task can be used. The present invention can replace the need to deploy different types of robots (horizontal articulated type, vertical articulated type with different types, etc.) with a single type of robot according to the present invention. This makes it possible to apply robots to areas where they were not previously available. As a result, equipment costs and maintenance costs can be significantly reduced, maintenance and management become easier, and the demand for robots increases.

(b), also has a simple structure and is structurally open to the member (a free end where the end is not connected to anything)
High rigidity can be achieved because there is no crack.・ (C) Also, when used as a heavy-load robot, the self-weight load acting on the second joints such as the wrist on the distal end and the upper arm can be reduced (by reducing the drive motor and reducer). The torque capacity applied to the robot is reduced, making it possible to design a robot that requires a large operating range in a compact manner.

(d), and the rotation angle of the joint is 180° as described above.
When the angle is 0°, the joints are mechanically receiving the load and no load is acting on the drive motor. Therefore, if this state is created as much as possible when operating the robot, the power consumption of the robot can be reduced. This makes it possible to considerably reduce the amount of energy used, and also extends the life of the drive motor.

(e) Piping or wiring that was conventionally exposed at the joint can be included, so even when a robot comes close to the machine for welding or assembly inside the machine, these piping or wiring can be removed. The possibility of damage can be reduced as much as possible.

[Brief explanation of drawings]

Fig. 1 is a skeleton diagram showing the configuration of an industrial robot according to an embodiment of the present invention, Fig. 2 is a partial side sectional view of the industrial robot showing a state in which piping and wiring are passed through the joints, and Fig. 3 ( a) to (d), and Fig. 4 (a) to (d) are simulation diagrams showing various movements of the industrial robot according to this embodiment together with a car as a work object, and Fig. 5 shows a diagram of the joints. FIG. 6 is a skeleton diagram showing the configuration of an industrial robot according to another embodiment. FIG. is an action diagram illustrating the rotational moment acting on the rotation center axis of the second joint, and FIG. 7(b) is an action diagram illustrating the rotation moment acting on the rotation center axis of the second joint. FIG. 8 is a side view showing a conventional parallel link type vertically articulated robot; FIG. 9 is a front view showing a conventional linear motion type vertically articulated robot; FIG. 10 9 is a side view showing one state of the vertically articulated robot of FIG. 9. FIG. A... Joint part (second joint part), B... Joint part (third joint part), D... Joint part (first joint part), E.
... Joint part (fourth joint part), 1... Base part, 5.
・Lower arm (member on the tip side of the second joint), Ol
... Rotation center axis (rotation center axis of the first joint) 11 ... Rotation center axis (rotation center axis of the second joint)

Claims (4)

[Claims] (1) In an industrial robot that is equipped with rotatable joints between members and whose base is installed on a substantially horizontal installation surface, the central axis of rotation of the first joint is a vertical axis. At the same time, the central axis of rotation of the second joint is constituted by an inclined axis that is not vertical or horizontal, and the tip of the member on the distal side of the second joint is parallel to the central axis of rotation of the second joint. An industrial robot characterized in that it is configured so that it does not exist above. (2), having a third joint part on the member on the distal side of the second joint part, which connects this member and a further distal member;
Claim 1, wherein the central axis of rotation of the third joint is constituted by an inclined axis that is neither parallel nor perpendicular to the distal end member of the second joint.
Industrial robots as described in Section. (3) The industrial robot according to claim 2, further comprising a rotatable fourth joint section provided on a member between the second joint section and the third joint section. (4) The industrial robot according to any one of claims 1 to 3, wherein a hollow part is formed in the joint part, and a cable hose is disposed in the hollow part.