JPH0445827Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention has a first arm that is pivotally supported on the robot body so that the swing axis is parallel to the swing axis of the first arm. The present invention relates to a posture maintaining device for a wrist at the tip of a second arm of a robot having a swingable second arm.

(Prior art) Conventionally, in this type of device, the wrist body is pivotally supported at the tip of the second arm so as to be swingable about a swing axis parallel to the swing axis of the first and second arms, and It is known that a link type parallel ruler mechanism consisting of links provided parallel to each arm is arranged between the wrist body and the wrist body to maintain a constant posture even when both arms swing. .

(Problem to be solved by the invention) In the above device, when the swing angle of the second arm with respect to the first arm becomes large, interference between the second arm and the link parallel to it is likely to occur. In a robot that swings the arm at a large angle, it is necessary to leave a large gap between the arms, which increases the size of the arm as a whole and reduces operability.

Therefore, in order to solve this problem, the inventor of the present application applied a wrapping-type parallel ruler mechanism conventionally used in drafting rulers, etc., and used a parallel ruler mechanism that uses a chain as a wrapping member to keep the wrist body in a constant posture. However, in this case, in consideration of the workability of chain tensioning and the change in posture of the wrist body due to chain stretching, it is necessary to make it possible to variably adjust the posture of the wrist body after chain tensioning. is desired.

The present invention solves the problems of the conventional device described above by configuring the parallel ruler mechanism as a winding type using a chain, and provides a device that also has the function of adjusting the posture of the wrist body after the chain is stretched. Its purpose is to.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a first arm that is swingably supported by the robot body, and a swingably supported arm that is swingably supported at the tip of the first arm. A second arm that is attached to the robot body and a wrist body that is pivotably supported at the tip of the second arm are pivoted through parallel pivot axes, and the first arm is attached to each side of the robot body. A drive source for the second arm and a drive source for the second arm are provided, and the wrist body is held in a constant posture by a parallel ruler mechanism, wherein the parallel ruler mechanism is connected to the wrist body on the swing axis of the wrist body. a first chain that extends between a first sprocket that is fixed to the first sprocket and a second sprocket that is pivotally supported on the swing axis of the second arm; The third
On the swing axis of the sprocket and the first arm,
and a second chain extending between the second chain and a fourth sprocket rotatably provided on the drive shaft of the second drive source, and the second chain is connected to the robot. It is characterized by being locked in a rotatably adjustable manner via an adjustment member provided on the main body.

(Embodiment) Hereinafter, a illustrated embodiment in which the present device is applied to a seam welding robot will be described.

Referring to FIG. 1, A indicates a seam welding machine having a pair of upper and lower electrode rolls a and b;
A robot body 2 is provided on the upper surface via a base 1 so as to be pivotable about a vertical axis by a drive source 3, and a horizontal swing axis is attached to the top of the robot body 2, as shown in FIG. A first arm 4 that can freely swing around X ₁ , and an axis line at the tip of the first arm 4.
A second arm ₅ that can swing freely around a swing axis X2 parallel to _X1 is supported, and a two-wheeled vehicle is attached to the wrist portion 6 at the tip of the second arm 5 via a work holder 7. A workpiece W, such as a fuel tank for a commercial vehicle, is held, and the welded portion of the workpiece W is continuously fed between the two electrode rolls a and b for automatic seam welding.

In the drawing, reference numerals 8 and 9 indicate drive sources for the first arm 4 and the second arm 5, which are mounted on the shaft supports 2a, 2a on both sides of the top of the robot body 2, which pivotally supports the first arm 4. An output shaft 10a located on the axis _X1 of a harmonic reducer 10 connected to the drive source 8 is connected to the first arm 4 so as to swing it, and a harmonic reducer 10 connected to the drive source 9 on the other side is connected to the first arm 4 to swing it. 11 output shaft 11a is positioned on the axis _X1 and is inserted and supported in the first arm 4, and a pair of drive sprockets 12, 12 are arranged on the output shaft 11a and spaced apart in the axial direction; A pair of driven sprockets 13, 13 are fixed to the second arm 5 on the mounting walls on both sides of the support shaft 5a located on the axis _X2 , and each drive sprocket 12 and each driven sprocket 13 The second arm 5 is made to swing through a pair of chains 14, 14 which are spanned between the two.

As clearly shown in FIG. 4, the wrist portion 6 includes a wrist arm 16 that is rotated around a vertical axis by a drive source 16a mounted on the wrist body 15, and has a cross at the lower end of the wrist arm 16. The mounting plate 7a of the workpiece holder 7 is connected via a joint 16b, and the wrist body 15 is placed horizontally on the upper end thereof on a swing axis _X3 parallel to the axes _X1 and _X2 . The tip of the second arm 5 is pivotally supported on a supporting shaft 15a located so that the wrist main body 15 can always be held in a constant posture so that the axis of the wrist arm 16 is perpendicular by a winding type parallel ruler mechanism. I made it.

To explain this point below, the wrist body 15
Then, as shown in FIG. ₃ , the first sprocket 17 is attached to the pin 1 on the swing axis
7a and bolts 17b, and
On the support shaft 5a on the swing axis _X2 of the second arm 5,
As shown in the second figure, the second
The sprocket 18 is pivotally supported, a first chain 19 is spanned between the two sprockets 17 and 18, and a third sprocket 20 is provided coaxially with the second sprocket 18 so as to rotate integrally therewith. 1 4th sprocket 2 of arm 4 swing axis X ₁
A second chain 22 is stretched between the wrist body 15 and the wrist body 15 to form a winding type parallel ruler mechanism that maintains a constant posture of the wrist body 15.

Here, according to a general wrap-type parallel ruler mechanism, the fourth sprocket 21 is fixedly engaged with the robot body 2, but in the illustrated example, the fourth sprocket 21 is rotated. For example, the output shaft 11a on the axis _X1 is supported via a bearing 21a, and the second chain 22 is rotatably locked to the robot body 2 via an adjustment member 23 as shown in FIG. I took it as a thing.

The adjusting member 23 includes a rotor 24 which is rotatably supported between the upper ends of the shaft supports 2a, 2a of the robot body 2, and a rotor 24 rotatably supported around an axis parallel to the axis _X1 . 4 A slide piece 25 attached to the sprocket 21 so as to be able to move forward and backward, and the slide piece 2
The slide piece 25 can be freely adjusted forward and backward by a pair of adjustment screws 25a and 25b, and the engagement can be adjusted by moving the sliding piece 25 forward and backward. The second chain 22 is connected to the fourth sprocket 2 via a linker 26.
1 so that the rotation can be adjusted.

In the drawing, 25c is a guide hole 25d formed in the slide piece 25 and extending in the advancing/retreating direction.
27 indicates a chain cover attached to the first and second arms 4 and 5.

(Function) First sprocket 17 and fourth sprocket 21
Since both sprockets 17 and 21 are connected via the first and second chains 19 and 22, the relative phase with respect to Even though the first and second arms 4 and 5 swing, the posture of the wrist main body 15 is maintained constant.

Here, if the load acting on the wrist body 15 generates a rotational moment around its swing axis _X3 ,
Tension acts on each chain 19, 22, and with long-term use, the posture of the wrist main body 15 changes due to the elongation of each chain 19, 22, and when tensioning each chain 19, 22, the wrist If the main body 15 is not held in a predetermined posture, the posture may become incorrect.
According to the present invention, the wrist body 1 can be adjusted by operating the adjustment member 23.
5's posture can be adjusted, and even if the posture is out of order, it can be easily corrected.

That is, according to the operation of the adjustment member 23, the first chain 22 is rotated together with the fourth sprocket 21 pivotally supported on the swing axis _X1 of the first arm 4, and the third sprocket 22 is rotated.
Sprocket 20, second sprocket 18, first sprocket
A first fixed to the wrist body 15 via the chain 19
The sprocket 17 is rotated, and the posture of the wrist body 15 is variably adjusted.

(Effect of the invention) As described above, according to the invention, the first arm 4 and the second arm 5 are driven independently by respective drive sources 8 and 9 provided on both sides of the robot body 2. Since the posture of the wrist main body 15 is maintained constant using a wrap-type parallel ruler mechanism using The structure allows the first and second arms to swing over a large angle with good operability, and since the parallel ruler mechanism is designed to fix the chain side of the sprocket chain that makes up this mechanism, its adjusting device This has the effect of simplifying the process.

[Brief explanation of the drawing]

Fig. 1 is a side view of a seam welding machine equipped with a robot equipped with the device of the present invention, Figs. 2 and 3 are enlarged cross-sectional views taken along - and - lines in Fig. 1, respectively, and Fig. 4 is an enlarged cross-sectional view of Fig. 2. FIG. 2 is a cross-sectional side view of the robot taken along the - line. 2... Robot main body, 4... First arm, 5...
...Second arm, 15...Wrist body, X ₁ , X ₂ , X ₃
...Rotating axis, 17...First sprocket, 18
...Second sprocket, 19...First chain,
20... Third sprocket, 21... Fourth sprocket, 22... Second chain, 23... Adjustment member.

Claims (1)

[Scope of utility model registration request] A first arm that is swingably supported on the robot body, a second arm that is swingably supported on the tip of the first arm, and a second arm that is swingably supported on the tip of the second arm. The wrist body is pivotally supported via parallel swing axes, and a drive source for the first arm and a drive source for the second arm are provided on both sides of the robot body, and the wrist body is mounted on a parallel ruler. In the apparatus in which the parallel ruler mechanism is held in a constant position by a mechanism, the parallel ruler mechanism is pivotally supported on the swing axis of the wrist body by a fixed first sprocket and the second arm on the swing axis of the wrist body. A first chain spanned between the second sprocket, a third sprocket provided coaxially with the second sprocket so as to rotate together with the second sprocket, and a third sprocket on the swing axis of the first arm and the third sprocket. The robot is configured as a winding type parallel ruler mechanism consisting of a second chain extending between a fourth sprocket rotatably provided on the drive shaft of two drive sources, and the second chain is provided on the robot body. What is claimed is: 1. A wrist posture holding device for a robot, characterized in that the wrist is rotatably locked through an adjusting member.