JPH06155365A - Indutrial robot - Google Patents

Abstract

PURPOSE:To eliminate consideration about interferences other than those of an arm with surroundings in rotation of swing base, etc., by protruding a balance mechanism only to the upper side from the rotating position of the arm. CONSTITUTION:An industrial robot is provided with a balance mechanism 14 which is provided with a fixed rod 26 installed on a rotating base 3 at the lower position of an arm swing center, a movable rod 31 installed on an arm 6, a bracket 28 of which base end is supported rotatably on the fixed rod 26 and in which a guide hole 30 to guide the movable rod 31 is formed at a position forward from the supported position, and a spring mechanism 35 which is installed between the movable rod 31 and the top end of the bracket 28 and energizes the movable rod 31 in the direction that it departs from the fixed rod 26.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an industrial robot.

[0002]

2. Description of the Related Art As an industrial robot, an installation base and
For example, Japanese Unexamined Patent Publication No. 2-303788 discloses a device having a swivel base supported by the installation base so as to be horizontally swivelable and an arm swingably supported by the swivel base. The balance mechanism for supporting the self-weight of the arm of this industrial robot is provided with a fixing pin above the arm supporting position of the swivel base, and a spring mechanism including a spring mounting member and a spring between the fixing pin and the tip side of the arm. Are arranged in series, and the spring mounting member is moved with respect to the motor provided at the arm supporting position when the arm swings.

[0003]

In the above industrial robot, since the spring mounting member, which is a part of the balance mechanism, is moved with respect to the motor when the arm is swung, the swinging angle of the arm is sufficiently large. In order to take it, the spring attachment member must be enlarged. Here, when the swivel base is swung, the interference between the arm and the surroundings is naturally taken into consideration.
There is no problem that the spring mounting member projects above the swinging position of the arm, but if it projects other than that, it is necessary to consider the interference of this protruding part in addition to the interference between the arm and the surroundings. However, if the spring mounting member is made large as described above, for example, when the swinging angle of the arm is small, the spring mounting member will project in the direction opposite to the swinging direction of the arm.

Therefore, an object of the present invention is to provide an industrial robot in which a part of the balance mechanism does not protrude below the swing position of the arm.

[0005]

In order to achieve the above object, an industrial robot of the present invention comprises a rotating base provided on an installation base so as to be horizontally rotatable, and is swingably supported by the rotating base. An arm, and a fixed pin provided on the swivel base below the swing center of the arm, a moving pin provided on the arm, and a swinging end of the fixed pin supported by the fixed pin. The bracket is provided with a guide hole for guiding the moving pin from the supporting position to the tip side, and the bracket is provided between the moving pin and the base end side of the bracket or between the moving pin and the tip side of the bracket. A balance mechanism including a spring mechanism for urging the pin away from the fixed pin is provided.

[0006]

According to the industrial robot of the present invention, when the arm is in the up-down direction, the bracket is also in the up-down position, and when the arm starts swinging, the moving pin provided on the arm is moved. Also moves integrally with the bracket and swings the bracket around the fixed pin in the same direction as the arm and at a larger angle than the arm while the moving pin moves in the guide hole. Alternatively, the spring mechanism provided between the arm and the tip side urges the moving pin in the direction of separating from the fixed pin to apply the urging force on the upper side in the swinging direction to the arm. Therefore, the balance mechanism projects only above the swing position of the arm.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An industrial robot according to an embodiment of the present invention will be described below with reference to FIGS. The industrial robot shown in FIG. 1 is installed on the ceiling with the top and bottom reversed. FIG. 1 shows the overall construction of a 6-DOF industrial robot of the present embodiment. In the figure, reference numeral 1 is an installation base that is installed on the ceiling. The installation base 1 is provided with a swivel drive unit 2, and the swivel drive unit 2 is provided with a swivel base 3 that horizontally swivels about an axis A. The swivel base 3 has flanges 4, 5
Is provided upright, and a first arm (arm) 6 swinging about an axis B orthogonal to the axis A is provided between the flanges 4 and 5. Further, the flange 5 is provided with a first arm drive unit 7.

At the tip of the first arm 6, the first arm 6
A second arm 8 which is connected to the arm 6 and swings around an axis C parallel to the axis B is provided, and a second arm driving unit 9 is provided at a connecting portion between the second arm 8 and the first arm 6.
Is provided, and a wrist drive unit 10a is further provided on the proximal end side of the second arm 8. Also, the second arm 8
A wrist mechanism 10 driven by a wrist drive unit 10a is provided at the tip of the wrist mechanism 10, and the wrist mechanism 10 is provided with a case 11, a case 12, and a mounting shaft 13.
Here, the case 11 is connected to the second arm 8 and rotates about an axis D parallel to the axis C.
Further, the case 12 is connected to the case 11 so as to rotate about an axis E orthogonal to the axis D. The attachment shaft 13 is for attaching a work tool or the like for making the robot work, and is attached to the case 12 so as to rotate about an axis F orthogonal to the axis E.

Here, the first arm 6 exists on a plane including the axis A. Further, the second arm 8
Is attached to the first arm 6 in a cantilevered manner, and the case 1
1 is attached to the side surface of the second arm 8 on the first arm 6 side in a cantilever manner, and the axis E exists in a plane including the axis A and orthogonal to the axis D. A balance mechanism 14 is provided between the flange 4 of the turning base 3 and the first arm 6.

As shown in FIG. 2, the first arm driving section 7
Is attached to the flange 5 formed on the swivel base 3 by the mounting seat 15
Has an electric motor 16 fixed via
An output shaft (not shown) of the motor 16 is arranged so as to coincide with the axis B. Further, the motor 1 of the flange 5
A speed reducer 18 is attached to the opposite side of 6 via a mounting seat 15. The speed reducer 18 converts low-torque and high-speed rotation of the motor 16 into high-torque and low-speed rotation, and the input shaft 19 and the output shaft 20 are provided on the same axis line that coincides with the axis line B. . Further, the speed reducer 18 has a bearing (not shown) therein, and the bearing can receive the addition in the radial direction or the thrust direction applied to the output shaft 20. This reducer 18
The input shaft 19 is attached to an output shaft (not shown) of the motor 16, and a rotation transmission means such as a key (not shown) is provided at a connecting portion between the input shaft 19 and the output shaft of the motor 16. Rotation of the output shaft of the motor 16 causes the input shaft 19 to rotate.
To be transmitted to.

A cylindrical portion 21 is provided at the base end of the first arm 6 provided on the swivel base 3, and the cylindrical portion 21 has a cylindrical portion 21 which is orthogonal to the axis of the cylindrical portion 21. The plate-shaped portions 22 and 23 are formed. And this first
In the arm 6, the axis of the cylindrical portion 21 is the first arm driving portion 7
The plate-shaped portion 23 is fixed to the output shaft 20 of the speed reducer 18, and the plate-shaped portion 22 is further fixed to the flange 4.
The motor 16 is driven by the motor 16 to swing about the axis B.

Next, the balance mechanism 14 of this embodiment will be described. As shown in FIG. 2, a fixing pin 26 protruding toward the first arm 6 is provided above the swing center axis B of the first arm 6 of the flange 4 (lower side in the installed state). , This fixed pin 26 has a bearing 27
The base end side of the bracket 28 is swingably supported via the. The first end of the bracket 28 is attached to the first side.
A support pin 29 protruding in a direction opposite to the arm 6 is provided, and an elongated hole-shaped guide hole 30 having a predetermined length along the extending direction of the bracket 28 is provided at a predetermined position on the fixed pin mounting side of the bracket 28. Are formed.

The first arm 6 has a moving pin 31 projecting toward the bracket 28 so as to be inserted into the guide hole 30.
Is provided, and a bearing 32 is fitted in the guide hole insertion position of the moving pin 31. Here, when the moving pin 31 is located closest to the fixed pin 26 of the guide hole 30, both the bracket 28 and the first arm 6 are in a state of being vertically aligned, and at this time, the fixed pin 26 and the moving pin 31 are arranged.
The support pins 29 are also arranged along the vertical direction. The guide hole 30 is formed to have a length that allows the moving pin 31 to move in the entire range of swing of the first arm 6.

The bearing 3 is provided between the moving pin 31 protruding outside the bracket 28 of the first arm 6 and the support pin 29 on the tip side of the bracket 28.
The spring mechanism 35 is supported in a state where the spring mechanism 35 is interposed therebetween. The spring mechanism 35 has a cylinder member 3 whose one end is supported by the support pin 29 and whose other end is substantially cylindrical.
6, and a piston member 37 whose one end side is supported by the moving pin 31 and the other end side is inserted into the cylinder member 36.
And have. A flange portion 38 is provided at the tip of the piston member 37 inside the cylinder member 36, and these flange portion 38 and the bottom portion 39 of the cylinder member 36 on the piston member insertion side are opposed to each other. A compression coil spring 40 that biases in the direction is provided.

As shown in FIG. 3, the installation base 1 is installed on the ceiling surface of the industrial robot having the above structure. In this state, when the first arm 6 extends in the vertical direction, the bracket 28 also moves in the vertical direction. At this time, the distance (L ₃ shown in FIG. ₃ ) between the support pin 29 and the moving pin 31 is maximum. And the first
When the arm driving unit 7 is actuated and the first arm 6 starts swinging, the moving pin 31 provided on the first arm 6 also moves integrally, and the moving pin 31 moves the guide hole 30 and fixes the bracket 28. The pin 26 is swung in the same direction as the first arm 6 at a larger angle than the first arm 6 (state shown in FIG. 3), and the swing angle θ ₁ of the first arm 6 is changed.
Is increased, the distance L ₃ between the support pin 29 and the moving pin 31 becomes shorter. Then, in this swinging state, the spring mechanism 35 provided between the support pin 29 and the moving pin 31 biases the moving pin 31 in the direction away from the fixed pin 26. As a result, the urging force is applied to the first arm 6 upward in the swing direction.

Here, the moment M _A due to its own weight and the moment M _S due to the balance mechanism 14 are calculated as follows. As shown in FIGS. 3 and 4, the combined weight of the second arm 8, the second arm drive unit 9, the wrist drive unit 10a, and the wrist mechanism 10 is W ₁ , the weight of the first arm 6 is W ₂ , and the axis BC. The distance between the center of gravity of L ₁ and W ₂ and the axis B
Let L ₄ be the distance from and, M _A = (W ₁ × L ₁ + W ₂ × L ₄ ) × sin θ ₁ If the angle is θ ₂ and the distance between the axis B and the moving pin 31 is L ₂ , then M _S = F × sin θ ₂ × L ₂ . As a result, the change of M _S and M _A with respect to θ ₁ exhibits the characteristics shown in FIG. And the motor 1
Torque T required 6 becomes T = M _S -M _A.

As described above, in the industrial robot, the balance mechanism 14 does not project laterally from the swivel base 3 because the balance mechanism 14 also extends in the vertical direction when the first arm 6 extends in the vertical direction. When the first arm 6 is in a swinging state, it projects upward from the first arm 6 only in the same direction as the first arm 6, that is, from the first arm 6 to the side other than the upper side and from the turning base 3 to the side. It does not stick out. Therefore, only the interference between the first arm 6 and the surroundings needs to be considered when the swivel base 3 is swung.
It is also possible to provide the balance mechanism 14 on the side of the first arm drive unit 7 in the above embodiment, and in this case also, the arrangement position of the fixing pin 26 can be sufficiently separated from the motor 16, It is possible to obtain a sufficient swing angle of the first arm 6 without causing the motor 16 and the like and the balance mechanism 14 to interfere with each other. Even with this configuration, the swing position of the first arm 6 is as described above. It is possible to prevent the balance mechanism 14 from projecting laterally from the swivel base 3 other than above.

Further, the bracket 28 of the balance mechanism 14
Since the fixing pin 26, which is the swing center of the first arm 6, is provided below the swing center of the first arm 6, the variation amount of the length of the spring mechanism 35, that is, the stress amplitude of the compression coil spring 40 is reduced. Therefore, the durability of the spring mechanism 35 is improved. Furthermore, since a space in the swing axis direction of the first arm 6 is free, a cable, an air hose, etc. can be passed through this space.

In the above embodiment, the balance mechanism 14 is provided between the support pin 29 on the tip side of the bracket 28 and the moving pin 31 of the first arm 6, but the bracket 28 has been described. It is also possible to provide between the base end side (for example, the fixed pin 26) and the moving pin 31 of the first arm 6 so as to bias them in the direction of separating them.

[0020]

As described above in detail, according to the industrial robot of the present invention, when the arm is in the vertical direction, the bracket is also in the vertical position, and the arm starts swinging. Then, the moving pin provided on the arm also moves integrally, and the moving pin moves the guide hole while swinging the bracket about the fixed pin in the same direction as the arm at a larger angle than the arm. A spring mechanism provided between the moving pin and the base end side or the tip end side of the bracket urges the moving pin in a direction of separating from the fixed pin to apply an urging force upward in the swinging direction to the arm. .
Therefore, a part of the balance mechanism does not protrude beyond the swinging position of the arm, so that it is not necessary to consider interference of this protruding portion in addition to interference between the arm and the surroundings when the swivel base swivels. .

[Brief description of drawings]

FIG. 1 is a perspective view showing an overall configuration of an industrial robot according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a balance mechanism and the like of an industrial robot according to an embodiment of the present invention.

FIG. 3 is a schematic side view showing a balance mechanism and the like when an industrial robot according to an embodiment of the present invention swings an arm.

FIG. 4 is a schematic diagram showing a distance relationship and the like of each part of the industrial robot according to an embodiment of the present invention.

FIG. 5 is a graph showing moment characteristics of an industrial robot according to an embodiment of the present invention.

[Explanation of symbols]

 1 Installation Base 3 Revolving Base 6 1st Arm 14 Balance Mechanism 26 Fixing Pin 28 Bracket 30 Guide Hole 31 Moving Pin 35 Spring Mechanism

Claims (1)

[Claims] 1. An industrial robot having a swing base horizontally swingably mounted on an installation base and an arm swingably supported by the swing base, wherein the swing base is below a swing center of the arm. A fixed pin provided on the arm, a movable pin provided on the arm, a base end side of the fixed pin swingably supported, and a guide hole for guiding the movable pin from the support position to the tip side. A balance comprising: a bracket; and a spring mechanism that is provided between the moving pin and the base end side of the bracket or between the moving pin and the tip end side of the bracket, and biases the moving pin in a direction separating from the fixed pin. An industrial robot characterized by having a mechanism.