JPH1158287A - Balance device for robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set off or reduce influence of load weight applied on a driving shaft of each of revolving shafts of a robot by a single device. SOLUTION: This device is constituted by installing one end (head end side) 6 of a spring 7 in the neighbourhood of a head end of an upper arm 4 of a robot or on a wrist part 5 and installing the other end (base part side) 8 on an installation part 30 provided on a ceiling 10. When the upper arm 4 is deflected downward (arrow A), the spring 7 extends, and restoring force F is generated. This restoring force F works to draw a head end part of the upper arm 4 upward and sets off or reduces a moment caused by load weight applied on driving shafts of the upper arm 4 and a lower arm 3. It is possible to set the installation part 30 free to move, too. Additionally, it is possible to use an air cylinder, etc., in place of the spring. The installation part of an end part of the base part side of a balance force generating mechanism can be also provided on a structure other than the ceiling 10, for example, on a support installed on a second shaft installation base 2 of the robot or a vertical wall surface, an inclined wall surface, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balance device used for reducing or removing a load on an industrial robot.

[0002]

2. Description of the Related Art When an industrial robot (hereinafter simply referred to as a "robot") takes an attitude in which an arm extends sideways, a large gravitational load is applied to a drive shaft of the arm and a drive shaft on a base side thereof. It takes. A balancer is used as a means for reducing such a load. The balancer used in the robot must naturally have a balance force generating mechanism that generates a balance force in a direction to cancel the change in response to a change in posture accompanying an increase in gravity load.

A mechanism using a coil spring or an air cylinder that expands and contracts in accordance with arm rotation is generally used as a balance force generating mechanism for canceling the gravitational load applied to the robot. By providing these balance force generating mechanisms for each arm that needs to cancel the load due to gravity, the gravitational load applied to the drive shafts of those arms is eliminated or reduced.

Therefore, the number of balance force generating mechanisms required for one robot is the same as the number of arms required to cancel the load due to gravity. Also, each part of the mechanism (coil spring, air cylinder, etc.) is mounted on the arm of the robot itself or on the robot body around it.

[0005] Therefore, a robot equipped with a balance device has a complicated body and an exterior structure, which tends to be large, making it difficult to simplify and reduce the size of the robot body, which has been an obstacle to reducing the cost of the robot.

If a high-performance actuator (arm drive motor) is used, it is possible to reduce or eliminate the use of the balance device, but such a high-performance actuator is naturally expensive and costly. High problems cannot be solved.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to eliminate the need to provide a balance force generating mechanism for each arm that needs to cancel the load due to gravity, and to avoid making the robot body and exterior complicated and large. It is an object of the present invention to provide a balance device for a robot capable of performing the above. The present invention also seeks to eliminate the obstacles to lowering the cost of the robot.

[0008]

SUMMARY OF THE INVENTION The present invention provides a balance force generating mechanism for generating a balance force for lifting up the most distal arm of the robot and a more distal portion than the lower arm, the lower arm, the upper arm, and the like. This technical problem has been solved by a balancing device provided so as to reduce or cancel the gravitational load applied to the arm.

According to the present invention, the distal end of the balance force generating mechanism of the balance device is attached to the most distal arm of the robot and the further distal portion thereof, while the other end is provided on the external support or the robot. It is attached to a support placed on a base in a fixed or movable manner.

A restoring force generating element is provided between the leading end and the other end of the balance force generating mechanism for generating a restoring force for preventing the leading end attached to the robot from moving downward. The balance force is generated by the restoring force.

As the external support, for example, a ceiling located above the robot or a member fixed thereto can be used. Further, as the restoring force generating element of the balance force generating mechanism, a spring or a hydraulic cylinder mechanism using air or other fluid can be employed.

[0012] In any of the embodiments of the present invention,
A balance force acts at a point where there is no pivot arm near the distal end (end effector side) of the robot, such as near the tip of the upper arm or at the wrist, and the load resulting from the reaction force drives each pivot arm. It does not touch the axis. Therefore, the influence of the load weight applied to the drive shaft of each swing arm can be canceled or reduced with a single device.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Several embodiments (first to sixth embodiments) will be described below with reference to FIGS. 1, 2,..., And FIG. 6 are diagrams illustrating the outline of the first embodiment, the second embodiment, and the sixth embodiment, respectively. In each embodiment, the robot equipped with the balance device is a standard vertical articulated robot of the same type.

That is, the robot in each embodiment is illustrated in a front view, and reference numeral 1 is fixed on a floor surface G by an installation base of the robot. On the installation base 1,
Mounting base 2 for second axis J2, which also serves as the revolving barrel for first axis J1
Is mounted on the second shaft mounting base 2, and a second shaft mechanism for turning a lower arm (first arm) 3 that is driven to rotate back and forth by a second shaft J2 is installed.

At the distal end of the lower arm (first arm) 3, there is provided a mechanism of a third axis J 3 for rotating the upper arm (second arm) 4 as the foremost arm. The tip is provided with a wrist 5 having an appropriate number of axes (typically three axes). Although not shown, various end effectors (heavy loads) are attached to the tip of the wrist 5 as needed. The configuration and function of the balance device mounted on the robot in each embodiment are as follows.

[First Embodiment] As shown in FIG. 1, one end (front end side) 6 of a spring 7 is attached near the front end of an upper arm 4 which is the most advanced arm of the robot, while the other end (base side).
8 is attached to a mounting portion 30 provided on a ceiling (or a beam fixed thereto) 10. When the upper arm 4 (and the wrist 5) of the robot swings downward (see arrow A) from the state shown in the figure, the spring 7 expands, and a restoring force F is generated. The restoring force F naturally acts to lift the tip of the upper arm 4 of the robot upward. That is, a balance force acting in a direction to offset the load weight is formed with the vicinity of the tip of the upper arm 4 as an action point.

It should be noted that since the base side of the balance force generating mechanism including the spring 7 is connected to the ceiling 10 outside the robot, the reaction force f of the balance force F (generally the same as F) The opposite is true), but does not affect any part of the robot. This means that the balance force F acting to lift the tip of the upper arm 4 upwards.
Thus, not only the gravitational load on the axis (J3) driving the upper arm 4 but also the axis (J2) driving the lower arm 3 moving back and forth
(A difference from the case where a balance force generating mechanism is provided between the lower arm 3 and the upper arm 4 like a conventional balancer).

In FIG. 1, the mounting portion 30 is fixed at an appropriate position on the ceiling 10 (in the vicinity of the top of the upper arm 4), but is provided as a movable mechanism as shown in FIG. 7, for example. You can do it. 7, reference numerals 31 and 32
Is a guide rail 33 extending in a direction perpendicular to the plane of the paper,
34 is a rail installation member for providing the guide rail 3
A running bridge 35 is bridged between 3 and 34. Therefore, the traveling bridge 35 can travel freely on the guide rails 33 and 34 in the direction perpendicular to the paper surface.

The traveling bridge 35 is provided with other guide rails 36 on the paper surface in the left-right direction, and guides a carrier 37 to which one end of a spring or a cylinder (to be described later) is connected. With such a mechanism,
When the direction of the reaction force f of the restoring force F (balance force) is tilted due to a change in the posture of the robot (particularly, rotation of the J1 axis), the carrier 37 is two-dimensionally moved in a direction in which the tilt is to be canceled (in a direction perpendicular to the paper surface). And the direction of action of the reaction force f is kept vertically downward, and the direction of action of the balance force F is kept vertically upward.

[Second Embodiment] As shown in FIG. 2, in this embodiment, as in the first embodiment, the spring 7 is suspended from the mounting portion 30 provided on the ceiling 30 to restore the spring 7 when it is extended. Power is used as balance power. This embodiment is different from the first embodiment in that the tip 16 of the spring 7
Only at the point where the mounting position is at the wrist 5.

Therefore, the operation is the same as that of the first embodiment except that the point of application of the balance force is further shifted to the hand side than the upper arm 4. That is, when the upper arm 4 (and the wrist 5) of the robot swings downward (see the arrow A) from the state shown in the figure, the spring 7 expands, and the restoring force F is generated. This restoring force F naturally acts to lift the wrist 5 of the robot upward. That is, a balance force acting in a direction to offset the load weight is formed with the attachment portion 16 on the wrist as an action point.

In this case, for the same reason as described in the first embodiment, the gravitational force acting on the wrist shaft and the shaft (J3) for driving the upper arm 4 is generated by the balance force F acting to pull the wrist 5 upward. This means that not only the load but also the gravitational load on the axis (J2) that drives the lower arm 3 that moves back and forth is reduced. In addition, the fixed mounting portion 30
Instead, for example, a movable mechanism as shown in FIG. 7 can be employed, similarly to the first embodiment.

[Third Embodiment] In the present embodiment, as shown in FIG. 3, the robot is fixed in place on the base 2 of the robot.
A column 20 extending upward is attached, and a horizontal extending portion 21 is extended from the column 20. Then, the spring 7 having one end (base side) 18 attached to the attachment portion 40 is moved along the horizontally extending portion 21 and turned downward by the pulley 22 to attach the tip 6 to the vicinity of the tip of the upper arm 4 of the robot. The operation of the balance device of the present embodiment is the same as that of the first embodiment.

That is, when the upper arm 4 (and the wrist 5) of the robot swings downward (see the arrow A) from the state shown in the figure, the spring 7 expands and a restoring force F is generated, and the direction is changed by the pulley 22. As a result, a balance force for lifting the vicinity of the tip of the upper arm 4 upward is obtained.

In this case, the base side of the balance force generating mechanism including the spring 7 is connected to the base 2 of the robot. Therefore, the reaction force of the balance force F is ultimately applied not to the structure outside the robot but to the base 2 of the robot. The moment and force acting on the base 2
Does not affect the load on the shaft (J3) for driving the lower arm 3 or the shaft (J2) for driving the lower arm 3.

After all, also in the case of the present embodiment, the drive shafts (J2 axis and J3
The gravitational load on the shaft is reduced.

The base 2 of the robot is a part that forms a revolving torso. Even if a moment or force (pressing force or tension) derived from the reaction force of the balance force F is applied, it is driven by the drive shaft (J1) of the revolving torso. There is almost no burden on the shaft).
Of course, bending occurs, but generally no major problem arises because the base 2 of the robot is generally rugged.

[Fourth Embodiment] As shown in FIG. 4, this embodiment has the same configuration as the third embodiment except that the mounting position of the tip 16 of the spring 7 is at the wrist 5. (Repeated description is omitted). Therefore, there is no particular difference in the operation from the third embodiment except for the point of application of the balance force.

That is, the upper arm 4 (and the wrist 5) of the robot
Swings downward (see arrow A), the spring 7 expands to generate a restoring force F, and the direction is changed by the pulley 22 so that the upper arm 4
It becomes a balance force that pulls up the vicinity of the tip.

Also in this case, for the same reason as described in the third embodiment, the balance force F acting to pull the wrist 5 upward applies to the wrist shaft and the shaft (J3) for driving the upper arm 4. Not only the gravitational load but also the gravitational load on the axis (J2) that drives the lower arm 3 that moves back and forth is reduced.

[Fifth Embodiment] The fifth embodiment is an example in which an air cylinder is used in place of a spring for the balance force generating mechanism, and the overall configuration is similar to the first embodiment. That is, as shown in FIG. 5, in the present embodiment, the air cylinder 50 is suspended from the mounting portion 30 provided on the ceiling 30, and the restoring force when the air cylinder 50 is extended is used as the balance force.

More specifically, the end (the tip of the air cylinder mechanism) 56 of the linear member 52 for pulling the piston 51 of the air cylinder 50 is attached to the vicinity of the tip of the upper arm 4 of the robot, while the other end (the base). Side) 58 is attached to the attachment portion 30 provided on the ceiling 10.

When the robot's upper arm 4 (and wrist 5) swings downward (see arrow A), the air cylinder 50 extends, and a restoring force F is generated. The restoring force F naturally acts to lift the tip of the upper arm 4 of the robot upward. That is, a balance force acting in a direction to offset the load weight is formed with the vicinity of the tip of the upper arm 4 as an action point.

Also in this embodiment, the air cylinder 50
Is connected to the ceiling 10 outside the robot, the reaction force of the balance force F does not act on any part of the robot. Therefore,
Due to the balance force F acting to pull the tip of the upper arm 4 upward, not only the gravitational load applied to the shaft (J3) for driving the upper arm 4 but also to the shaft (J2) for driving the lower arm 3 moving back and forth. Gravity load is also reduced. Further, in place of the fixed mounting portion 30, a movable mechanism as shown in FIG. 7, for example, can be adopted as in the first embodiment.

[Sixth Embodiment] This embodiment is also an example in which an air cylinder is used as a balance force generating mechanism.
The overall configuration is similar to the third embodiment. That is, as shown in FIG. 6, a column 20 extending upward is attached to an appropriate position on the base 2 of the robot, and a horizontal extending portion 21 is extended from the column 20. Then, the air cylinder 50 having one end (the base side) 58 attached to the attachment portion 40 is arranged along the horizontally extending portion 21. The linear member 52 that pulls the piston 51 of the air cylinder 50 is turned downward by using the pulley 22, and the end (the end of the air cylinder mechanism) 56 is attached near the end of the upper arm 4 of the robot. Also in the present embodiment, when the upper arm 4 (and the wrist 5) of the robot swings downward (see the arrow A), the air cylinder 50 extends, and the restoring force F is generated. This restoring force F is, of course,
Thus, the tension is applied to the linear member 52 which has been turned downward, and acts to pull the upper arm 4 upward. In this way, the balance force derived from the restoring force F of the air cylinder 50 acts on the mounting portion 56 as an action point, and offsets or reduces the load weight.

Also in this case, since the base side of the balance force generating mechanism including the air cylinder 50 is connected to the base 2 of the robot, the reaction force of the balance force F is ultimately reduced by a structure outside the robot. Not the base of the robot 2
And does not affect the load on the axis (J3) for driving the upper arm 4 or the axis (J2) for driving the lower arm 3.

Therefore, also in the case of the present embodiment, the drive shafts (the J2 axis and the J3 axis) of both the upper arm 4 and the lower arm 3 are acted upon by the balance force F acting to lift the tip of the upper arm 4 upward.
The gravitational load on the shaft is reduced.

Although the six embodiments have been described above,
The present invention is not limited to these embodiments, and for example, the following modifications are possible. (1) Instead of the support 20 used in the third, fourth, and sixth embodiments, a wall (vertical wall, inclined wall, etc.) of a structure outside the robot is used, and a spring and an air cylinder are used. Attach the base side of the balance force generating mechanism including the above.
In this case, the horizontally extending portion 21 is attached to the wall surface (an existing structure may be used instead).

(2) In the third, fourth, fifth, and sixth embodiments, the distal end mounting portions 6, 56 of the balance force generating mechanism are not located near the distal end of the upper arm 4, but as in the second embodiment. Bring it to part 5.

(3) A balance force generating mechanism using a restoring force generating mechanism using another kind of fluid, such as a hydraulic cylinder, is used instead of the air cylinder.

(4) Series connection of spring and air cylinder, etc.
A balance force generating mechanism using a plurality of restoring force generating elements is employed.

[0042]

According to the present invention, a balance force acts on a position where there is no turning arm near the distal end (end effector side), such as near the tip of the upper arm of the robot or the wrist, and the balance force acts on the position. The load resulting from the force is not applied to the drive shaft of each turning arm. Therefore, the influence of the load weight applied to the drive shaft of each swing arm can be canceled or reduced with a single device.

Further, through this, it is possible to prevent the robot body and exterior from becoming complicated and large, and to contribute to the cost reduction of the robot.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a second embodiment of the present invention.

FIG. 3 is a diagram illustrating a third embodiment of the present invention.

FIG. 4 is a diagram illustrating a fourth embodiment of the present invention.

FIG. 5 is a diagram illustrating a fifth embodiment of the present invention.

FIG. 6 is a diagram illustrating a sixth embodiment of the present invention.

FIG. 7 is a diagram illustrating an example in which a mounting portion on the base side of the balance force generating mechanism is configured to be movable.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Installation base 2 2nd axis mounting base 3 Lower arm (1st arm which moves back and forth) 4 Upper arm (2nd arm) 5 Wrist part 6 and 16 Mounting part on the spring tip side 7 Spring 20 Post 21 Horizontally extending part 22 Pulley 30, 40 Spring or air cylinder base mounting part 31, 32, 36 Rail mounting member 33, 34 Guide rail 35 Traveling bridge 37 Carrier 50 Air cylinder G Floor 51 Piston 52 Linear member 56 Front end of air cylinder mechanism Attachment part 58 Attachment part at base side of air cylinder mechanism

Claims (6)

[Claims] 1. A balancing device for a robot, comprising: a robot having a balance force generating mechanism for generating a balance force for lifting an arm at the most distal end of the robot and a part further at the distal end than the arm. The tip of the balance force generating mechanism is attached to the arm on the most hand side and a portion further on the hand side, and the other end of the balance force generating mechanism is attached to a support outside the robot. A restoring force generating element is provided between the tip and the other end of the balance force generating mechanism to generate a restoring force that attempts to prevent the tip from moving downward. The balance device, wherein the balance force is generated due to the following. 2. The balance device according to claim 1, wherein the external support is a ceiling located above the robot or a member fixed thereto. 3. The mounting device according to claim 1, wherein the other end of the balance force generating mechanism is attached to the external support via a mechanism that movably supports the other end. Balance device. 4. A balance device for a robot, comprising: a balance force generating mechanism for generating a balance force for lifting an arm at the most distal end of the robot and a portion further at the distal end than the arm. The tip of the balance force generating mechanism is attached to the most hand-side arm and a portion further on the hand side, and the other end of the balance force-generating mechanism is attached to a support installed on the base of the robot. A restoring force generating element is provided between the tip and the other end of the balance force generating mechanism, the restoring force generating element generating a restoring force that attempts to prevent the tip from moving downward. The balance device, wherein the balance force is generated by the restoring force. 5. The balance device according to claim 1, wherein the balance force generating mechanism includes a spring as the restoring force generating element. 6. The balance device according to claim 1, wherein the balance force generating mechanism includes a hydraulic cylinder mechanism as the restoring force generating element.