JP2011062767A - Industrial robot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure in which a reduction gear can be miniaturized by keeping optimal balance force at all times in the wrist of an industrial robot. <P>SOLUTION: In the industrial robot equipped with a wrist unit, a balancer 16 is provided between a ring 15 rotatably provided on a flange 14 and a wrist base 10. The wrist unit provided on an arm tip includes: a first reduction gear; a second reduction gear disposed so as to be orthogonal with the first reduction gear; and a third reduction gear rotating coaxially with the first reduction gear, and includes the balancer disposed so that the wrist base provided to the first reduction gear and the flange provided to the third reduction gear become both ends. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an industrial robot that conveys large heavy objects.

A market where you would like to use a robot to grip large heavy objects such as body bodies from the side and transport them between the floors of the upper and lower floors when handling heavy objects in industrial robots (hereinafter simply referred to as “robots”) There is a request.
However, when a large heavy object is gripped from the side, the center of gravity of the gripping part and the transported object becomes longer from the attachment flange of the robot wrist shaft, so that an excessive load acts on the wrist shaft. For this reason, the wrist axis speed reducer and motor need to be about the same size as the basic axis that supports the wrist of conventional robots, and the basic axis requires a larger speed reducer and motor, so the robot itself becomes larger. There are technical challenges.
In order to solve this general technical problem, conventional industrial robots reduce the driving speed of each axis to reduce the load on the wrist axis, or use large reducers and motors. It is structured to withstand high loads on the wrist shaft. Some of the second arms 2 incorporate a balancer mechanism (see, for example, Patent Document 1).

JP 2000-792 A (page 2-3, FIG. 1)

In conventional robot mechanisms, a large speed reducer and motor must be used for the wrist shaft to achieve a structure that can withstand heavy loads, so there are also basic shaft speed reducers and motors that support it. There was a problem of increasing the size.
The present invention has been made in view of such problems, and the moment load in the rotational direction of the second axis reduction gear and the second axis reduction without restricting the movement of the second axis and the third axis in the wrist three axes. The balance force is adjusted according to the angle of the wrist 1st axis and the 2nd wrist axis while reducing both the rotational direction of the 3-axis reducer and the moment load in the vertical direction. An object of the present invention is to provide a structure capable of reducing the size of a reduction gear.

In order to solve the above problem, the present invention is configured as follows.
The invention described in claim 1 is an industrial robot provided with a wrist unit, wherein a balancer is provided between a ring and a wrist base that are rotatably provided on a flange.
According to a second aspect of the present invention, the balancer is disposed symmetrically with respect to the central axis of the flange.
According to a third aspect of the present invention, the wrist unit is provided at the tip of an arm, the first reduction gear, the second reduction gear arranged to be orthogonal to the first reduction gear, the first A third reducer that rotates coaxially with one reducer, and includes a wrist base provided in the first reducer and a balancer arranged with both ends of a flange provided in the third reducer. It has been done.
According to a fourth aspect of the present invention, the wrist unit includes the balancer, and the lower arm also includes a second balancer.
According to a fifth aspect of the present invention, the balancer is composed of an air cylinder having two supply ports, and adjusts the pressure according to the arrangement angle of the air cylinder when gripping a conveyed product.
According to a sixth aspect of the present invention, the balancer is composed of either an active balancer composed of a spring balancer or the like, or a servo balancer composed of a hydraulic cylinder or the like.

According to the present invention, since the load on the speed reducer of the wrist unit can be reduced, it is possible to provide an industrial robot that is relatively small and can transport heavy objects by reducing the size and weight of the wrist shaft speed reducer and motor.

The side view of the robot which shows Example 1 of this invention The wrist unit side view of the robot which shows Example 1 of this invention 1 is a top view of a wrist unit of a robot showing Embodiment 1 of the present invention. Balancer sectional view showing Example 1 of the present invention Operational diagram of Embodiment 1 of the present invention Operational diagram of Embodiment 1 of the present invention Operational diagram of Embodiment 1 of the present invention Balancer sectional view of Example 2 of the present invention

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a side view of a robot to which the present invention is applied. FIG. 2 is a side view of the wrist unit. FIG. 3 is a top view of the wrist unit.
First, an industrial robot will be described with reference to FIG. The robot 1 has a swivel head 3 rotatably connected to a vertical axis A1 with respect to a fixed base 2. The swivel head 3 is parallel to a fixed surface of the fixed base 2 and perpendicular to the axis A1. The arm 4 has an arm 4 that is rotatably connected, the arm 4 has an arm 2 that is rotatably connected to an axis A3 that is offset in parallel with the axis A2, and a wrist unit 6 is disposed at multiple ends of the arm 2. Yes. Further, the arm 2 has a link 7 rotatably connected to an axis A7 parallel to the axis A3 on the side opposite to the wrist unit 6, and the link 7 is rotatably connected to an axis A8 parallel to the axis A7. The other end of the link 8 is connected to the swivel head 3 so as to be rotatable about an axis A2 and includes a counterweight. Further, a balancer made up of an air cylinder 18 that reduces the load is provided on both sides or one side of the arm 4 to reduce the capacity of the motor that rotationally drives the arm 4 about the A2 axis.
Next, the structure of the wrist unit 6 will be described.
The wrist unit 6 has a speed reducer 9 at the tip of the arm 5, and has a wrist base 10 that is rotatably connected to an axis A4 perpendicular to the axis A3 via the speed reducer 9. The wrist base 10 is a speed reducer 11. And has a wrist 12 rotatably connected to an axis A5 perpendicular to the axis A4 via a speed reducer 11, the wrist 12 having a speed reducer 13, and a right angle to the axis A5 via the speed reducer 13. And a flange 14 rotatably connected to the shaft A6.
Further, the flange 14 has a ring 15 that is rotatably connected to the shaft A6, and the ring 15 has an air cylinder 16 that is rotatably connected to an axis A9 that is perpendicular to the shaft A6 and is arranged symmetrically across the shaft A6. The other end of the air cylinder 16 is coupled to the wrist base 10 so as to be rotatable with respect to an axis A10 parallel to the axis A9.
Next, FIG. 4 is a sectional view of the air cylinder 16. 5, 6 and 7 are explanatory diagrams of the operation.
First, when the workpiece 17 is gripped by the flange 14 and the connecting shaft A9 of the air cylinder 16 is positioned above the axis A4, the initial state is shown in FIG. 5, and compressed air is supplied to the air tank 18 of the air cylinder 16 to load Pull the ring 15 in the direction of F1. Next, in the case of FIG. 6 rotated by 180 ° around the axis A4, air in the air tank 18 of the air cylinder 16 is extracted, air is supplied to the air tank 19, and the ring 15 is pushed in the direction of the load F2. Further, by controlling the air pressure in the air tank 18 and the air tank 19 according to the rotation angle from the initial state to 180 °, the balance force acting on the speed reducers 11 and 13 can be kept optimal. .
Similarly, in the case of FIG. 7 rotated 90 ° around the A5 axis from the initial state, the balance force acting on the speed reducers 11 and 13 is kept optimal by making the air pressure in the air tank 18 and the air tank 19 uniform. Can do.
Further, even if the flange 14 rotates around the A6 axis from the initial state, the ring 15 is connected to the flange 14 so as to freely rotate. Is possible.
The difference between this embodiment and the prior art is that a balancer for reducing the load on the speed reducer 11 is attached to the ring 15 of the flange 14 via the speed reducer 13 so that the operations of the A5 axis and the A6 axis are Without limiting the operation, the moment load in the rotational direction of the speed reducer 11 and the moment load in the rotational direction and the vertical plane direction of the speed reducer 13 can be reduced, and the air cylinder 16 is used for the balance mechanism, By controlling the air pressure in the air tank 18 and the air tank 19 in the air cylinder 16 according to the rotation angle, the balance force can be kept optimal.

Next, another embodiment similar to the present invention is shown in FIG. Since the basic form is the same as that of the first embodiment, only different parts will be described.
The wrist unit 20 is obtained by changing the air cylinder 16 of the first embodiment to a spring balancer 21. In the case of a spring balancer, the load direction always acts in the direction of the load F1. Therefore, if the operation range of the A4 axis is less than ± 90 degrees from the initial state, the load on the reducers 11 and 13 is reduced. If a load is applied and the A4 axis is fixed, the load reducing force to the speed reducers 11 and 13 can be adjusted by adjusting the spring force, so that a high load can be handled.

1 Robot 2 Fixed base 3 Turning head 4 Arm 1
5 Arm 2
6 Wrist unit 7 Link 1
8 Link 2
9, 11, 13 Reducer 10 Wrist base 12 Wrist 14 Flange 15 Ring 16 Air cylinder 17 Work piece 18 Air cylinder

Claims (6)

  An industrial robot provided with a wrist unit, wherein a balancer is provided between a ring rotatably mounted on a flange and a wrist base.   2. The industrial robot according to claim 1, wherein the balancer is disposed symmetrically with respect to a central axis of the flange.   The wrist unit is provided at the end of the arm and rotates coaxially with the first speed reducer, the second speed reducer arranged to be orthogonal to the first speed reducer, and the first speed reducer. A third reduction gear, comprising a balance base arranged at both ends of a wrist base provided in the first reduction gear and a flange provided in the third reduction gear. The industrial robot according to 1.   The industrial robot according to claim 1, wherein the wrist unit includes the balancer and the lower arm includes a second balancer.   2. The industrial robot according to claim 1, wherein the balancer includes an air cylinder having two supply ports, and adjusts the pressure according to an arrangement angle of the air cylinder when gripping a conveyed product.   2. The industrial robot according to claim 1, wherein the balancer is configured by either an active balancer configured by a spring balancer or the like, or a servo type balancer configured by a hydraulic cylinder or the like.

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