JPH04143091A - Device for adjusting focus position of laser beam of laser robot - Google Patents

Abstract

PURPOSE:To smoothly attain the focus position adjusting effect of a laser beam by disposing a rotating nut of a ball screw mechanism for rotation-to-direct action conversion and a motor for rotational driving thereof, etc., in the rear part of a robot wrist and providing the ball screw shaft of the ball screw mechanism on the circumference of a laser head. CONSTITUTION:A direct action means is provided on the rear end side of the laser head 26 engaged internally with a direct action guiding means 25a projectingly provided at the front end of the robot wrist 25. The rotating nut 32 of the ball screw mechanism for rotation-to direct action conversion is provided within the corner in the rear part of the robot wrist 25. The rotating nut 32 is rotationally driven by a driving motor MF. The ball screw shaft 34 is screwed to the rotating nut 32 and one end of the ball screw shaft 34 is fixed to the circumference of the laser head 26. The linear action guiding mechanism which imparts a stopper effect to the laser head at all times and has no interference with the work is constituted in this way.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to improvements in industrial laser robots, and in particular,
The present invention relates to a compact laser beam focal position adjusting device for adjusting the focal position of a laser beam with respect to a workpiece by moving a laser head with a built-in condensing lens provided at the tip of the robot wrist of a laser robot in a straight line.

[Prior art]

A laser robot is equipped with a laser beam conduit, a mirror for changing the optical path, etc. inside the robot body to guide the laser beam to the tip of the robot's wrist, and a condensing lens built into the laser head attached to the tip of the robot's wrist. It has been well known that a laser beam is emitted from the laser head and irradiated onto the surface of a workpiece, and is used for laser processing such as cutting the workpiece. Such a laser robot is equipped with a mechanism for moving a laser head containing a built-in condensing lens straight back and forth relative to the robot's wrist in order to focus the laser beam on the surface of the workpiece. Such an adjustment device for adjusting the focal position of the laser beam emitted from the laser head is provided at the meeting point between the robot wrist and the laser head, and one example of the prior art is as follows.
Illustrated in FIG.

In the conventional example shown in FIG. 3, a robot wrist 5 is attached to the tip of a robot arm 4 of a laser robot, and a laser beam guided inside the robot arm 4 is transmitted to the robot arm 4.
The laser beam enters the robot wrist 5 through the optical path changing mirror 4a provided at the leading edge of the laser head 6, and then passes through a mirror (not shown) again within the robot wrist 5 to change the optical path. Via the condensing lens 7,
Target workpiece from the exit port 8 of the lens head 6 (not shown)
It has a configuration that emits light toward the surface of the

Therefore, a laser beam focal position adjustment device is required to focus the laser beam emitted from the laser head 6 onto the work surface, and is integrally formed downward from the cylindrical protrusion 5a provided at the front end of the robot wrist 5. The ball screw 10 of the rotation-linear conversion mechanism is rotationally driven by a drive motor Mf provided on the back side of the plate-shaped motor holding bracket 9.
On the other hand, the ball screw 10 is fixed to a plate-shaped bracket 11 that is integrally formed below the laser head 6.
A ball/screw nut 12 engaged with the robot wrist 5 is provided, and the laser head 12 is guided by a linear guide 13 externally mounted via a bracket 11 as the ball/screw nut 12 moves straight forward and backward (arrow f). By moving the condensing lens 7 back and forth,
It has a configuration in which the laser beam emitted from the emission aperture 8 is focused on the work surface.

[Problem to be solved by the invention]

However, as is clear from the configuration of the conventional example shown in FIG. Since it is formed inside the laser head 6, it is difficult to have a structure in which it is built into the robot wrist 5 or the laser head 6 for boat fishing. Moreover, by rotating the ball/screw 10 with the drive motor Mf, if the laser head 6 is moved straight forward and backward via the bracket 11 hanging below the laser head 6, the ball/screw nut 12 cannot be easily tightened. The structure is such that the bracket 11 holding the ball/screw nut 12 interferes with the target workpiece during laser processing such as cutting a workpiece in a three-dimensional space because it is disposed at a bulge on the outer periphery of the laser head 6. Furthermore, there is a risk that the drive motor Mf and the motor holding bracket 9 may also interfere with the workpiece during laser processing. Furthermore, since the linear guide 13 that allows the laser head 6 to move straight is provided in a structure that extends around the outer periphery of both the robot wrist 5 and the laser head 6, this linear guide 13 is also a cause of interference with the workpiece during laser processing. easy to become

Although not shown in the laser head, the robot arm 4 has an assist gas tube that injects assist gas to the laser beam irradiation part to stabilize laser processing.
The outer periphery of the robot wrist 5 is directly connected to a piping system arranged in a crawling manner.

For this reason, when the robot arm 4 or the robot movable mechanism provided at its front stage operates, a tensile force unexpectedly acts on the assist gas tube via the piping system. In the structure in which the linear guide 13 shown in the figure is removed and a sliding bearing is simply provided inside, the laser head 6 may rotate or a moment force may be applied to the laser head 6, which is held at the bottom of the laser head 6 via the bracket 11. There is a risk that an excessive radial load will act on the engaged portion between the ball/screw nut 12 and the ball/screw 10, which may impede the straight movement of the laser head 6.

Therefore, the main object of the present invention is to solve the various problems that occur in the laser beam focal position adjustment device in the conventional laser robot mentioned above.

Another object of the present invention is to provide a laser having a configuration in which the arrangement of elements for straight movement of the laser head is reduced as much as possible from the peripheral area of the laser head, and interference with a workpiece can be avoided. An object of the present invention is to provide a laser beam focus position adjustment device in a robot.

[Means to solve the problem]

In view of the above-mentioned object of the invention, the present invention arranges various elements such as a drive motor for driving the laser head in a straight line at the fourth corner of the back of the robot's wrist in a laser robot, and The structure is such that the minimum number of elements for focus position adjustment operations are arranged as possible.

In addition, an engagement structure with a ball splint and a spline nut is used to guide the laser head in a straight line in the front-rear direction, and it is built into the part where the robot wrist and the laser head meet.

That is, according to the present invention, in a laser beam focus position adjusting device for a laser robot that adjusts the focal position of a laser beam by moving a laser head having a condensing lens in a straight line, linear motion means provided on the rear end side of the laser head so as to internally engage with the guide means; a drive motor and a rotary direct drive means provided at various locations on the back of the robot wrist to be rotatably driven by the drive motor; A rotating nut of a ball/screw mechanism for dynamic conversion, and a ball/screw of a ball/screw mechanism for rotating/linear conversion, which is screwed onto the rotating nut and has one end fixed to the laser head. The present invention provides a laser beam focus position adjustment device for a laser robot.

[Effect]

A rotating nut of a ball/screw mechanism for rotation-to-linear conversion and a motor for driving the rotation of the nut are placed in the corner area of the back of the robot wrist, and around the laser head are balls/screws of a ball/screw mechanism. Since only the shaft is provided, there is almost no risk of interference even when the laser head approaches the target work. In addition, a ball spline mechanism that guides the forward and backward movement of the laser head is provided inside the area where the front end of the wrist and the rear end of the laser head meet.
Not only can interference with the workpiece be avoided, but the laser head is prevented from rotating, so even if a tensile force is applied from the outside to the assist gas tube, the laser head will not be affected by it.

Hereinafter, the present invention will be further explained based on the embodiments shown in the accompanying drawings.
Explain in detail.

[Example] FIG. 1 is a perspective view showing a main part of the configuration of a laser beam focal position adjustment device in a laser robot according to the present invention;
Fig. 2 is a front view showing the overall configuration of an industrial laser robot having a laser head equipped with a parfocal position adjustment device, and Fig. 3 is a main part showing a conventional example of a laser beam focal position adjustment device in a laser robot. FIG.

Referring to FIG. 1, a laser robot equipped with a laser beam focal position adjusting device according to an embodiment of the present invention has an optical path changing mirror mechanism 24a at the tip of a robot arm 24 having a laser beam conduit inside. A robot wrist 25 is provided coupled to the optical path changing mirror mechanism 24,
A mirror (not shown) for changing the optical path of the laser beam is also provided inside the wrist 25. A hollow cylindrical protrusion 25a is formed in the front part of the robot wrist 25, that is, in the front part on the opposite side of the robot arm 24, and the central part has a hollow hole that forms a conduit for the laser beam. A ball spline nut (path shown) is attached to the inner circumferential wall surrounding the shaft.

The laser head 26, which has a ball spline 26a meshing with this ball spline nut at its rear end portion and has a built-in laser beam focusing lens 27, moves forward and backward (indicated by arrow F) with respect to the protrusion 25a of the robot wrist 25. It is provided so that it can move straight in the direction shown) by a ball spline mechanism.

The laser head 26 has a laser beam exit port 28 at the front end of a conical portion at the tip.

Now, a bracket 29 attached to the robot wrist 25 and formed in an appropriate shape such as a box shape or a plate shape is integrated into the corner area of the back of the robot wrist 25 that is generated by coupling with the robot arm 24. is attached to. An electric motor M is mounted on the robot arm 24 side of this bracket 29.
, is installed. This electric motor MF is, for example,
It consists of a well-known servo motor, and its output shaft protrudes to the opposite side of the bracket 29 and rotates a pulley 30. A well-known belt 31 such as a belt or a toothed belt wound around this pulley 30 is mounted on a bracket 29 with a rotation bearing (
The rotation is transmitted to a driven pulley 33 attached to a rotatably held ball/screw nut 32 via a
Therefore, the ball screw nut 32 is configured to rotate in both forward and reverse directions. In addition, the ball screw nut 32
A ball/screw shaft 34 is engaged with. That is, one end 34a of the ball/screw shaft 34 is connected to the ball/screw nut 32.
It penetrates through and protrudes toward the motor side of the bracket 29.

On the other hand, the other end 34b of the ball/screw shaft 34 is fixed to a low-height mount 35 protruding from the side surface of the laser head 26 via an appropriate fixing means 36 such as a fixing screw means.

In other words, the ball/screw shaft 34 is maintained unrotatable.

In addition, the electric motor MF is used to tighten the ball screw nut 32.
When the ball/screw shaft 34 is rotated, the ball/screw shaft 34 moves linearly in its axial direction due to the rotation-linear conversion action of the ball/screw mechanism. Therefore, the laser head 2
6 performs a straight movement in the direction indicated by arrow F, and can perform a focal position adjustment operation of the laser beam. During this straight movement, the straight movement is smoothly guided by the engagement between the ball spline nut inside the cylindrical protrusion 25a and the ball spline at the rear end of the laser head 26, but the latter does not rotate relative to the former. has formed an unacceptable structure.

The laser head 26 having the laser beam focal position adjustment device configured as described above is provided at the tip of the laser robot as shown in the circle "■" in FIG.

In the laser robot shown in FIG. 2, a robot arm 24 has a hollow structure, extends rearward, and is articulated to a robot body 40, and the robot arm 24 is driven by a feed screw by a drive motor M. It is attached via a mechanism 41 so that it can be tilted up and down around a W axis 42 as shown by an arrow W. In addition, the robot body 40 is mounted on a swivel table 43,
The swivel table 43 is provided so as to be able to pivot relative to the robot base 44 around a vertical axis 45 as indicated by an arrow θ, thereby enabling pivoting in the θ direction. The rotating motion of the robot body 40 is driven and caused by a drive motor Mθ attached to the robot base 44, and is executed via a deceleration mechanism provided inside the robot base 44. Furthermore, the robot arm 24 is capable of linear movement in the direction indicated by arrow R by a drive motor (not shown) built into the top of the robot body 40 and a ball/screw mechanism operated by the drive motor. It is configured. Furthermore, robot wrist 2
The robot arm 5 has a configuration in which two wrist drive motors (not shown) built into the tip of the robot arm 24 allow turning motion with two degrees of freedom as indicated by arrows β and T. Therefore, the laser robot of this embodiment is formed as a five-axis robot having five degrees of freedom in three-dimensional space.

Although not shown, an assist gas injection tube is provided at the outer periphery of the laser head 26.

According to the configuration of the laser robot described above, the robot arm 2
A laser head 26 attached to the tip of the robot arm 2 via the robot wrist 25 controls the rotation of the robot body 40 and the robot arm 2.
The laser beam exit port 28 can be directed to a desired position in the three-dimensional space by using the vertical and linear movements of 4 and the two turning movements of the robot wrist 25. Therefore, the laser beam can be directed to the target workpiece. By irradiating the laser beam, it is possible to perform predetermined laser processing such as cutting a workpiece.

The laser beam is guided from a laser oscillator (not shown) provided outside the robot body to the top of the robot body 40 or the bottom of the robot base 44 through an appropriate conduit.
Next, a conduit path of a normal laser robot is formed, which is guided through the robot body 40 and the robot arm 24 to the laser head 26 via a hollow conduit path inside the robot body.

Note that 46 indicates a piping path in which fluid piping for assist gas, electrical wiring, etc. are housed.

Next, the operation of the laser beam focal position adjusting device in the laser robot described above will be explained with reference to FIGS. 1 and 2.

Laser robot θ rotation, W elevation rotation, R axis linear movement,
By turning β and T, the laser beam output port 28 of the laser head 26 is positioned near the target workpiece by the control action of the robot control device in a well-known manner. When the predetermined approach position to the workpiece is reached, the electric motor Mp is activated by a command signal from the robot control device, and the nut 32 of the ball/screw mechanism is driven to rotate in either the forward or reverse direction to drive the ball/screw shaft. 34 is moved straight at a predetermined speed in the direction of arrow F, and the laser head 26 is moved straight forward and backward at the same speed. As a result, the laser beam condensing lens 27 built into the laser head 26 asymptotically moves linearly toward the workpiece or moves away from the workpiece, focusing the laser beam at a predetermined position on the workpiece surface. Make it hot.

Although the means for detecting this in-focus state is not shown, it is detected by an appropriate focus detecting means, and the motor M is stopped. In this way, the adjustment of the focus position of the laser beam by the forward and backward linear movement of the laser head 26 is completed.

〔Effect of the invention〕

According to the present invention, a ball/screw shaft 3 is provided on the outer circumference of the laser head, which is a component of a focus position adjustment device that moves the laser head straight back and forth to focus the laser beam.
4, and the drive motor etc. are stored in the corner area of the back of the robot's wrist, so the laser beam is not only focused, but also during the laser processing process. Even when the head moves in three-dimensional space, there is no interference with the target workpiece.

Furthermore, a linear motion guide mechanism for guiding the linear motion of the laser head is formed by a ball spline mechanism provided at the robot wrist and the rear end of the laser head, and the ball spline mechanism is configured to engage inside the robot wrist. Therefore, the laser head is always provided with a rotation prevention effect,
Moreover, a linear motion guide mechanism that does not interfere with the workpiece is constructed. As a result, the fear of excessive load acting on the ball/screw mechanism is eliminated, and smooth linear motion of the ball/screw mechanism is achieved. In other words, the focal position adjustment function of the laser beam can be smoothly achieved.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a main part of the configuration of a laser beam focal position adjustment device in a laser robot according to the present invention;
Fig. 2 is a front view showing the overall configuration of an industrial laser robot having a laser head equipped with a parfocal position adjustment device, and Fig. 3 is a main part showing a conventional example of a laser beam focal position adjustment device in a laser robot. Perspective view. 24...Robot arm, 25...Robot wrist, 26
... Laser head, 26a... Ball spline nut, 27... Condensing lens, 28... Laser beam exit port, 29... Bracket, 32... Ball/screw nut, 34... Ball/screw shaft. Figure (prior art) Figure 3

Claims (1)

[Claims] 1. A laser beam focus position adjustment device for a laser robot that adjusts the focus position of a laser beam by moving a laser head having a condensing lens in a straight line; a linear motion means provided on the rear end side of the laser head so as to internally engage with the guide means; a drive motor provided in a corner of the back of the robot wrist; and a rotational motion motion driven by the drive motor. A rotary nut of a ball/screw mechanism for dynamic conversion; and a ball/screw of a ball/screw mechanism for rotation/linear motion conversion, which is screwed onto the rotary nut and has one end fixed to the laser head. A laser beam focus position adjustment device for a laser robot, characterized in that: 2. The linear motion guide means protrudingly provided at the front end of the robot wrist is comprised of a hollow ball spline nut element, and the linear motion means is comprised of a hollow ball spline element provided at the rear end of the laser head. 1. A laser beam focus position adjustment device in the laser robot according to 1.