JPH0592290A - Vertical multi joint type laser robot for industrial use - Google Patents

Abstract

PURPOSE:To reduce the energy loss and to precisely transmit and receive the beam by connecting the beam path outlet end of the turn table and the laser beam path inlet end of the arm, and passing the laser beam, through in the laser beam path means. CONSTITUTION:In a outer part beam path tube 12, the lower end part is supported freely rotationally to a turn table 2, and the upper end part is fixed at the upper part of a center arm 3, and bend mirrors as a pair of opposite laser beam deflecting means fixed respectively to the lower end part and the upper end part as one body are provided. A ball screw 4b is rotated with the drive of a servo motor 4a, the 2nd shaft bearing unit 5 is moved to the axial direction of this ball screw 4b, the center arm 3 and the outer beam path tube 12 are rotated to Y direction together.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical articulated industrial laser robot used for laser processing such as welding and cutting using laser energy.

[0002]

2. Description of the Related Art Recently, a vertical articulated industrial type, which is equipped with a beam output end for emitting a laser beam, that is, a laser head at the tip of a robot body, is adapted for welding, cutting, deburring, etc. A laser robot (hereinafter, simply referred to as a laser robot) is provided. In this type of laser robot, it is necessary to have an optical structure that guides the laser beam introduced from the laser light source to the robot body to the nozzle type beam output unit attached to the tip of the robot wrist, and the laser beam is guided along the irradiation path. It must meet the need to provide freedom of movement for wrist movement.

FIGS. 3 and 4 show, for example, Japanese Patent Laid-Open No. 2-200.
1 is a side view and a rear view of a conventional laser robot shown in Japanese Patent No. 391, 391, which has a swivel body 42 on a robot base 41, and a first robot arm on a chest 42a offset from the upper end of the swivel body 42 to the front side. A rear end 44b of the second robot arm 46 is pivotally attached, a rear end 46b of a second robot arm 46 is pivotally attached to a front end 44a of the first robot arm 44, and a laser beam emitting portion is further attached to a front end 46a of the second robot arm 46. A robot wrist 48 is attached to form the. The first and second robot arms 44 are provided on both sides of the chest portion 42a of the swing body 42,
The electric motors Mw and Mu that form a turning drive source around the W axis and the U axis are provided.

A hollow ball spline nut 52 and a ball spline shaft 54 are provided between the top 42b of the swivel barrel 42 and the rear end 46b of the second robot arm 46. The ball spline nut 52 is attached to the hollow cylinder 50. The lower end of the hollow tube 50, which is fixed, has a mirror for reflecting a laser beam to change the course of the laser beam.
Is connected to the swivel body 42 via. The upper end of the hollow ball spline shaft 54 is connected to the second robot arm 46 via the laser optical path connector 60.

Next, the operation will be described. From the laser light oscillator provided outside the laser robot body, through the external conduit 62a, the external optical path mirror 62b, and the external conduit 62c mounted on the laser robot body, the swivel barrel 4 of the robot
The laser light introduced to the upper end of 2 is reflected by the mirror unit 64.
The laser beam is reflected and redirected by a, is reflected and redirected again by the mirror unit 64b in the laser beam connector 58, is introduced into the laser beam path means 50, and then is reflected by the mirror unit 64c in the laser beam connector 60. After the course is changed, the mirror unit 64d provided at the rear end 46b of the second robot arm 46 again makes a straight line in the second robot arm 46 after reflection and course change, and reaches the robot wrist 48. ..

[0006]

As for the conventional laser robot, in addition to FIG. 3 shown as a conventional example, in many general laser robots, the first robot arm 44 has the swivel barrel 42 as shown by l in FIG. Since it is configured to be shifted forward from the center of rotation of the robot, in order to rotate the robot and further move the first robot arm 44 in the W direction, the expansion and contraction between the laser optical path connectors 58 and 60 is inevitable. It is structured so that a free light pipe can be secured.

Therefore, from the viewpoint of the optical axis characteristic, it is desirable that the pair of mirror units 64b and 64c facing each other be firmly fixed, and play or bending deformation occurs in this portion during use. Then, the mirror unit 64b,
Accurate transmission and reception of laser light will not be performed between 64c,
In some cases, it becomes impossible to perform accurate machining at the tip.

Further, an RV speed reducer (manufactured by Teijin Seiki) is generally used as a speed reducer for the robot in the second and third axis drive parts of the conventional laser robot shown in FIGS. 3 and 4. When a motor of the second axis is shifted from the center of rotation like a laser robot manufactured by Comau in Italy, a timing belt and a gear train are used. Lost motion, backlash, hysteresis loss and transmission error cannot be avoided (Ex, output shaft angle is 1 to 3 minutes), and it has been difficult to improve the absolute accuracy beyond this.

The present invention has been made to solve the above problems, and it is possible to obtain a laser robot having a high absolute accuracy while reducing energy loss of the laser light so that the laser light can be accurately transmitted and received. To aim.

[0010]

A laser robot according to the present invention has a turntable including a laser optical path, an opening at substantially the center, and is articulated to the turntable by an articulation axis A. No. 1 arm, a second arm including a laser optical path and articulated to the first arm by an articulation axis B, and a screw rod end so as to be positioned at the opening of the first arm. The turntable is rotatably engaged, the nut portion is engaged with the opening of the first arm, and a first ball screw for turning the first arm and an opening at a substantially central portion are provided. And having one end portion on the second arm, which is located on one side of the joint coupling axis A.
The other end of the link is rotatably engaged with the turntable, and the screw rod end is pivotally engaged with the turntable so that the opening of the link is located. Is located on the other side of the articulation axis A and the second ball screw that engages with the opening of the link and pivots the second arm through the link,
A laser light path outlet of the turntable provided on the joint coupling axis A, having a pair of laser light polarization means for polarizing the laser light at right angles, the laser light path tube between the pair of laser light polarization means being fixed. A laser light path means for connecting the end and the laser light path entry / exit end of the second arm provided on the joint coupling axis B is provided.

[0011]

In the present invention, the first ball screw is screwed with the nut portion engaged with the opening portion of the first arm, and the second ball screw is engaged with the nut portion engaged with the opening portion of the second arm. The front arm is rotated by screwing through the first arm and the second arm, and the laser light passage means connects the optical path exit end of the turntable and the laser light path entrance / exit end of the second arm. Allows laser light to pass.

[0012]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to FIGS. 1 and 2 show a driving structure for a second axis and a third axis of a laser robot according to the present invention, FIG. 1 is a side view thereof, and FIG. 2 is a rear view thereof. In the figure, 1 is a base fixed to the floor, 2 is a turntable which is rotatably supported with respect to the base 1, and 3 is a lower end portion of which both sides of the turntable are projected downward. It is supported by 2 and can rotate freely in the Y direction.
A center arm as a first arm having a rectangular window 3a as an opening penetrating in the Y direction at the center thereof is a portion corresponding to the second shaft of the present invention.

Reference numeral 4 is incorporated in a window 3a provided at the center of the center arm 3, and connects the turntable 2 and the center arm 3 by a servomotor 4a and a preloaded ball screw 4b as a first ball screw. A second shaft drive unit, 5 is a second shaft bearing unit as a nut portion for rotatably supporting the center arm 3 and the prestressed ball screw 4b, and 6 is an upper end of the center arm 3 for freely rotating in the Z direction. The front arm is supported and corresponds to the third shaft of the present invention.

Reference numeral 7 denotes a rear portion of the front arm 6 which is parallel to the center arm 3 and has a rectangular window 7a as an opening penetrating in the Y direction at the center thereof. The links A and 8 as the second arm are the lower end of the center arm 3, the center of rotation, and the link A7.
Is a link B whose lower end is rotatably connected and is parallel to the front arm 6. The link A7 and the link B8 form a link.

Reference numeral 9 is incorporated in a window 7a provided at the center of the link A7, and the turntable 2 and the link B are provided.
The third shaft drive unit 10 for connecting 8 with the servo motor 9a and the preloaded ball screw 9b as the second ball screw serves as a nut portion for rotatably supporting the link B8 and the preloaded ball screw 9b. Third axis bearing unit, 11 is the turntable 2
Is an arm balancer having a built-in coil spring or the like for rotatably connecting the upper part of the center arm 3 and the upper part of the center arm 3.

An external optical path tube 12 is a laser optical path tube whose lower end is rotatably supported by the turntable 2 and whose upper end is fixed to the upper part of the center arm 3, as an example. A bend mirror A13 and a bend mirror B14 as a pair of opposing laser light polarization means are integrally fixed to the lower end and the upper end, respectively. Reference numeral 15 is a bend mirror unit provided in the front part of the front arm 6, and 16 is a processing head having a parabolic mirror for receiving the reflected light from the bend mirror unit 15 and further condensing it. ..

Next, the operation will be described. First, regarding the drive structure of the second shaft, when the servomotor 4a is driven, the prestressed ball screw 4b rotates. Then, the second shaft bearing unit 5 screwed to the ball screw 4b moves in the axial direction of the ball screw 4b as the ball screw 4b rotates. Then, since the second shaft bearing unit 5 is supported by the center arm 3, it is transmitted to the center arm 3 and the external optical path tube 12 as the second shaft bearing unit 5 moves, and as a result, the center arm 3 and the external optical path are transmitted. The tube 12 together Y shown in FIG.
Rotate in the direction.

Next, regarding the drive structure of the third shaft, the ball screw 9b preloaded when the servomotor 9a is driven.
Rotates. Then, the third shaft bearing unit 10 screwed to the ball screw 9b moves in the axial direction of the ball screw 9b as the ball screw 9b rotates. Then, since the third shaft bearing unit 10 is supported by the link A7 via the link B8, the third shaft bearing unit 10 is transmitted to the link B8, the link A7, and the front arm 6 as the third shaft bearing unit 10 moves, and as a result, the front arm 6 is transmitted. The arm 6 rotates in the Z direction shown in FIG.

As described above, the external optical path tube 12 is disposed between the joint connecting portion of the center arm 3 and the joint connecting portion of the front arm 6 and is fixed to the joint connecting portion. In addition, since the external optical path tube 12 does not expand and contract, there is no fear of rattling or bending deformation of the external optical path tube 12, and variation due to fluctuation of the optical path length.

Further, a ball screw 4b is engaged with the center arm 3 for rotating the center arm 3,
Further, a ball screw 9b is engaged with the link A7 to rotate the front arm 6 via the link A7. When the center arm 3 and the front arm 6 rotate, the center arm 3, the ball screw 4b and the front arm 6 are rotated. Drive parts for the second axis and the third axis, such as the ball screw 9b and the ball screw 9b, are arranged so as not to interfere with the external optical conduit 12, and the center arm 3,
Since the prestressed ball screws 4b and 9b are used to rotate the front arm 6, it is possible to reduce the lead error of several μm as a characteristic possessed by the ball screws 4b and 9b in terms of accuracy.

[0021]

As described above, according to the present invention, the first
Ball screw is engaged with the nut portion engaged with the opening of the first arm, and the second ball screw is engaged with the nut portion engaged with the opening of the second arm. arm,
As the second arm is rotated, the laser light passage means is configured to connect the optical path exit end of the turntable and the laser light path entrance end of the second arm to allow the laser light to pass therethrough. Can accurately transmit and receive light and can accurately process at the tip. In addition, since a preloaded ball screw is used for the arm drive part, conventional speed reducers, timing belts, gear trains, etc. are not used, so there is little lost motion or play, or hysteresis loss or transmission error, and absolute accuracy is improved. It has the effect of significantly improving.

[Brief description of drawings]

FIG. 1 is a side view showing a drive structure for a second axis and a third axis of a vertical articulated industrial laser robot according to an embodiment of the present invention.

FIG. 2 is a rear view showing the driving structure of the second axis and the third axis of the vertical articulated industrial laser robot according to the embodiment of the present invention.

FIG. 3 is a side view of a conventional vertical articulated industrial laser robot.

FIG. 4 is a rear view of a conventional vertical articulated industrial laser robot.

[Explanation of symbols]

 1 Base 2 Turntable 3 Center Arm 3a Window 4 Second Axis Drive Unit 4a Servo Motor 4b Preloaded Ball Screw 5 Second Axis Bearing Unit 6 Front Arm 7 Link A 7a Window 8 Link B 9 Third Axis Drive Unit 9a Servo Motor 9b Preloaded ball screw 10 Third axis bearing unit 11 Arm balancer 12 External optical path tube 13 Bend mirror A 14 Bend mirror B 15 Bend mirror unit 16 Processing head

Claims (1)

[Claims] 1. A turntable including a laser optical path, a first arm having an opening at a substantially central portion and articulated to the turntable by an articulation axis A, and a laser optical path. A second arm, which is articulated to the first arm by an articulation axis B, and a screw rod end which is pivotally engaged with the turntable so as to be positioned at the opening of the first arm. , A nut portion is engaged with the opening portion of the first arm and has a first ball screw for rotating the first arm, and an opening portion at a substantially central portion, and one side of the joint coupling axis A. The one end of which is rotatably engaged with the second arm and the other end of which is rotatably engaged with the turntable, and the threaded rod end is positioned so that the opening of the link is positioned. While being pivotally engaged with the turntable, The nut is engaged with the opening of the link and is located on the other side of the second ball screw that pivots the second arm through the link and the joint coupling axis A, and polarizes the laser light at a right angle. It has a pair of laser light polarization means, the laser light path tube between the pair of laser light polarization means is fixed, and the laser light path exit end of the turntable provided on the joint joint axis A and the joint joint axis B. A laser beam path means for connecting the laser beam path entrance / exit end of the second arm provided to the vertical articulated industrial laser robot.