JPH08229861A - Industrial robot - Google Patents

Abstract

PURPOSE: To provide an industrial robot high in accuracy and excellent in maintenance workability while having high rigidity by link structure. CONSTITUTION: In an industrial robot 100, an upper base end connecting arm 7a and a lower base end connecting arm 7b are provided at a column 1 so that the turning shafts are coaxially disposed. An upper tip connecting arm 9a and a lower tip connecting arm 9b are further provided in the turnable state on the tip side of the respective base end connecting arms 7a, 7b, and both tip connecting arms 9a, 9b are provided with a work head 11 for applying machining to a workpiece. The positioning of the work head 11 is performed by the control of a servo motor provided on the tip side of the upper base end connecting arm 7a.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an industrial robot,
In particular, the present invention relates to an industrial robot that performs a work requiring high rigidity such as a drilling or deburring work or a screw tightening work.

[0002]

2. Description of the Related Art In recent years, the progress of robots has been remarkable and many kinds of robots have been introduced and operated in factories. In particular, dedicated robots have spread in the work fields of transportation, assembly, welding, painting, etc., contributing to the improvement of work efficiency. Because of the usefulness of such robots, the robots have been applied to processing fields such as cutting and grinding.

Conventionally, several robots have been proposed as a robot for performing cutting and grinding. That is, there is a configuration in which an arm portion extending from the robot main body in a substantially horizontal direction is provided, a vertical moving portion that is moved in the vertical direction is attached to the tip of the arm portion, and a machining tool is attached to the vertical moving portion. In addition, Japanese Patent Laid-Open Nos. 2-298484 and 4-31 disclose high rigidity.
There is a robot using a four-bar linkage mechanism as disclosed in Japanese Patent No. 5591. In these robots, two rotatable arms are provided on a U-shaped column, and a servomotor for rotating and driving these two arms is provided on the pivot shaft. Further, a tip arm capable of further swiveling is pivotally supported at the tip of each arm, and both tips of the tip arm are pivotally supported by the same axis. A processing head for processing a workpiece is provided at one of the tip ends of the tip arm, and the tip arm is vertically moved to drive the workpiece.

[0004]

In the case of a robot having the above-described structure, in the case of a structure in which one arm is connected in order, a servo motor for driving is mounted on each arm to operate the arms. Position accuracy is maintained, but when a large reaction force is received from the work at the tip such as drilling,
It is difficult to maintain the posture of the robot body with high accuracy against the large moment force, and in order to increase its rigidity, it is necessary to use a wide arm and a wide rotary joint, and in particular, The structure of a part such as a moving part that requires precision must be made more complicated, and the cost is inevitable. On the other hand, the above-described four-bar linkage robot has a structure in which four arms receive the reaction force of the tip portion, and the structure achieves high rigidity without enlarging each arm. However, in the conventional structure, since the two servo motors for driving the arms are respectively arranged in the rotary nodes provided in the U-shaped column, the two servo motors on the lower side are arranged. The servo motor that drives the arm is sandwiched between the arm and the ground, so if a failure occurs and maintenance of the motor is required, the work is extremely complicated and requires the worst replacement. In such a case, a great deal of labor is required, such as having to move the entire heavy body.

Further, since each servo motor is provided at a rotation node of the base end arm and rotationally drives the base end arm to position the machining head provided at the tip end portion, the distance between the arms is increased. Between the joints, for example, mechanical backlash in the connecting portion between the proximal end arm and the distal end arm cannot be absorbed by the correction of the control drive of the servo motor, and there is a limit in achieving high accuracy such as position accuracy.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an industrial robot having high rigidity and excellent maintenance workability while having high rigidity due to a four-bar link structure. To do.

[0007]

According to the structure of claim 1, the industrial robot of the present invention is provided with the first prime mover for rotationally driving the first connecting arm, and further with respect to the first connecting arm. Since the second prime mover is provided so as to relatively rotationally drive the third connecting arm, the second prime mover drives the third connecting arm with respect to the first connecting arm rotationally driven by the first prime mover. Since it is driven to rotate, the link structure of the arm structure enables high-precision positioning while maintaining high rigidity without including rattling of the turning node. Further, according to the second aspect, by further providing the working head on the third connecting arm which is rotationally driven by the second prime mover, the working head can be positioned with higher accuracy. Claim 3
According to, the arm on which the prime mover is installed
By being provided above, a configuration that facilitates maintenance such as removal of the prime mover can be realized.
According to the fourth aspect, a balanced four-node link configuration can be achieved by making the first rotary node and the second rotary node coaxial. Further, as described in the fifth and sixth aspects, by providing each rotary node at the free end of each connecting arm, the arm can be efficiently configured with respect to the operation region.

According to a seventh aspect of the present invention, a uniform structure can be obtained by making the distances between the pivoting nodes of the arms the same, and the influence of inertial force during movement of the robot is made uniform. be able to. According to claim 8, the arm is made of a material having a thermal expansion coefficient smaller than that of aluminum such as iron or cast iron, so that it is possible to reduce the influence of heat of the servomotor and suppress thermal displacement. According to the ninth aspect, each arm is provided inward of the order, and the structure is downsized toward the tip portion, whereby the overall rigidity can be maintained without increasing the size of the main body. In addition, the required torque of the second prime mover can be reduced. According to the tenth aspect, the rigidity of the main body can be further increased by forming the main body in a U-shape and providing the first and second connecting arms inside the main body. According to the eleventh aspect, by providing the main body with the installation surface parallel to the rotation plane of the arm and the installation surface perpendicular to the arm, the directionality of the work head can be changed as necessary, and a flexible robot is configured. can do.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below.
A description will be given based on the figure. In FIG. 1, an industrial robot 1
Column 1 which is the main body of 00 is an installation surface 1 installed on the ground
a. The column 1 has a U-shaped side surface, and the upper portion 2a has a servo motor 3 whose axis is in the vertical direction in the figure.
There is provided a speed reducer 4a connected to the rotary shafts of a and the servomotor 3a.

As shown in FIG. 5, which is a partially enlarged view, a servo motor 3a provided so as to be inserted into the upper portion 2a is provided with a servo motor 3a via flanges 30 and 31.
The end surface of the object is arranged so as to project downward from the lower end of the upper portion 2a. The rotation axis of the servo motor 3a is the speed reducer 4
a, and the other end is connected to the rotating shaft 5a via a plurality of gears or the like. A flange 50 is formed on the rotary shaft 5a, and one end of the flange is abutted and fixed to a lower end surface of an upper base end connecting arm 7a serving as a first connecting arm. A lower outer peripheral portion of the flange 50 of the rotating shaft 5a is inserted into a supporting portion 2c formed so as to project from the column 1 below the connecting arm 7a, and is rotatably supported via a bearing 34. At the same time, a seal 35 is inserted in the end surface portion of the support portion 2c so that dust or the like does not enter the bearing 34.

A bearing 33 is inserted between the flange 31 and the upper base end connecting arm 7a to rotatably support between the flange 31 and the upper base end connecting arm 7a. Further, like the seal 35, the seal 32 is provided near the upper end surface of the upper base end connecting arm 7a. Therefore, the speed reducer 4a is rotationally driven by the rotational driving of the servo motor 3a, and the upper rotary shaft 5a is rotated at a predetermined gear ratio to thereby rotate the upper proximal end connecting arm 7a.
Is rotationally driven in a plane parallel to the installation surface with the upper rotary shaft 5a as the rotary shaft.

Further, a rib 2e is provided on the upper portion of the support portion 2c as shown in FIG. This rib 2
e is configured for the purpose of increasing the rigidity of the support portion 2c, and prevents the shaft of the rotating shaft 5a from being displaced. In addition, since the rib 2e is provided, the upper base end communication arm 7a is
It is cut into a slant in the vicinity of the rib 2e.
In other words, it has both increased rigidity and compactness.

As shown in FIG. 3, an upper base end connecting arm 7a.
A servomotor 3b, which is a second prime mover fixed above the tip of the motor, has its rotation shaft extended downward into the upper base end connecting arm 7a and has a speed reducer 4b at its tip.
Is further connected, and a pivot shaft 8a corresponding to a third rotation node extends downward from the speed reducer 4b. Also,
The upper base end connecting arm 7a projects downward with its tip end facing the upper end connecting arm 9a, and the above-mentioned pivot 8a is rotatably supported by a pair of cross roller bearings inside the protruding part. ing. The lower end of the pivot 8a is fixed to an upper tip arm 9a which is a third connecting arm. With the configuration described above, the upper tip connecting arm 9a is driven to rotate in parallel to the turning plane of the upper base connecting arm 7a with the upper base connecting arm 7a as a reference by the rotational driving of the servo motor 3b.

On the lower portion 2b of the column 1 of FIG. 1, there is installed a lower rotating shaft 5b which is a rotatably fixed second rotating node. The lower rotary shaft 5b is provided so as to project upward from the lower part 2b of the column 1 and to be coaxially arranged apart from the upper rotary shaft 5a. It is rotatably supported by the protruding support portion 2d. The lower rotating shaft 5b is rotatably supported by a bearing (not shown) such as a bearing so that the lower base end connecting arm 7b, which is a second connecting arm, does not interfere with the upper base end connecting arm 7a. It is driven to rotate. The swivel drive plane is swiveled to a plane parallel to the swivel plane of the upper base end connecting arm 7a.

The arm length of the lower base end connecting arm 7b is substantially the same as the arm length of the upper base end connecting arm 7a,
A lower tip connecting arm 9b, which is a fourth connecting arm, is rotatably connected to a free end side corresponding to a tip side of the lower base connecting arm 7b via a pivot 8b corresponding to a fourth rotating node. The lower tip connecting arm 9b is arranged above the lower base connecting arm 7b, can pivot in a plane parallel to the pivot plane of the other arm, and is arranged at a position where it does not interfere with the upper tip connecting arm 9a. ing. Further, the tip ends of the upper tip connecting arm 9a and the lower tip connecting arm 9b are rotatably supported by the connecting shaft 10 serving as the fifth rotation node.

The upper tip connecting arm 9a is formed in a U-shape at the tip thereof, and the tip of the lower tip connecting arm 9b is inserted into the inside of the upper tip connecting arm 9a. It is supported so that it surrounds the tip. The arm length between the pivot shaft 8a and the connecting shaft 10 of the upper tip connecting arm 9a and the lower tip connecting arm 9b.
The arm length between the pivot shaft 8b and the connecting shaft 10 is substantially the same, and the inter-axial lengths of the above-mentioned upper base end connecting arm 7a and lower base end connecting arm 9a are also substantially the same. Is. Fixed surface 1 at the tip of the upper tip connecting arm 9a
A work head unit 11 is provided on the 0a side. The work head 11 has a box-shaped frame 12 provided with an up-and-down moving unit 13 that moves up and down in a direction of an arrow Z in the drawing, which is a direction perpendicular to the installation surface.

As shown in FIG. 6, the working head 11 has a servo motor 14 mounted on an upper end portion of a frame 12 and is connected to a rotary shaft of the servo motor 14 to form a frame 1.
Rotatable ball screw 1 extending in the Z direction inside 2
7, a ball screw nut 23 screwed to the ball screw 17, and a gear 24 fixed to the ball screw nut 23 are provided. The ball screw nut 23 includes a housing 26 and a bearing 2.
It is rotatably supported by the frame 12 via 7,
The gear 24 fixed to the housing 26 and the gear 25 attached to the output shaft of the servomotor 14 mesh with each other to transmit the rotational force of the motor to the ball screw nut 23. An LM guide 15 is provided between the end surface 12 a of the frame 12 and the slider 16 so that the slider 16 can slide in the Z-axis direction. The LM guide 15 includes a plurality of bearings 15a provided on the end surface 12a of the frame 12.
And a rail 15b fitted to the bearing 15a and slidable in the Z-axis direction. The rail 15b is fixed to the mounting surface 16b of the slider 16.

Below the slider 16 is the frame 12
The ball screw 17 is attached to the flange portion 16c protruding toward
The lower end of is fixed by fastening means such as screws. The ball screw 17 receives a rotational force with respect to the rotation of the ball screw nut 23, but due to the connection with the LM guide 15 slider 16, the rotation is blocked, so the ball screw 17 is rotated.
The rotational force is converted into a driving force in the axial direction to move up and down, and the slider 16 is moved up and down in the arrow Z direction together with the slider 16.

A rubber packing 60 is provided on the frame 12.
A casing 61 is provided with bolts sandwiching it, and the casing 61 prevents the motor 14 and the ball screw 17 from being exposed to ensure waterproofness and dustproofness. Below the frame 12, the shield part 1 is also provided to prevent water and dust from entering the inside of the frame 12.
2b is provided. Further, a bellows 62 is provided around the lower part of the ball screw 17, and the bellows 62 is connected and fixed to the upper portion of the flange portion 16c and the lower portion of the frame 12, and is expandable and contractible.
Even if the ball screw 17 is lowered by the motor 14, it is always in a sealed state. As described above, the working head 11
Motor 14, ball screw 17, nut 2 provided in
3. All the bearings 27 are hermetically sealed to ensure waterproof and dustproof properties.

A bearing box 18 is connected to the slider 16, and a machining motor 19 is attached to the upper end of the bearing box 18. A drive shaft 20 is rotatably passed through the bearing box 18, the upper end of the drive shaft 20 is connected to the processing motor 19, and the lower end projects from the lower surface of the bearing box 18.
The chuck 21 is provided with a detachable processing tool 22. The processing tool 22 is attached to the chuck 21 with its axis in the vertical direction (the arrow Z direction in the drawing). Also, depending on the hole diameter to be processed, the processing tool 2
2 can be replaced.

Next, the operation of the industrial robot 100 will be described. In FIG. 1, each servo motor 3a, 3b, 1
4 is provided at the tip of the upper portion 2a of the column 1 and the upper proximal end connecting arm 7a by operating the control box 30 provided with a control device for controlling the rotation amount, the rotation speed, etc. of the motor 4 and the rotation speed of the motor 19. Each servo motor 3a,
When 3b is rotated, the upper base end connecting arm 7a and the upper end connecting arm 9a are swung in the horizontal plane via the speed reducers 4a and 4b, so that the lower base connecting arm 7b and the lower end connecting arm 9b are also driven. The shape is swiveled in the horizontal plane. Therefore, the processing tool 22 of the work head 11 is moved in a plane horizontal to the installation surface.

At this time, by adjusting the respective rotation amounts of the servomotors 3a and 3b, the machining tool 22 is enclosed within a region surrounded by a chain double-dashed line passing through one point, two points and three points shown in FIG. , And can be moved in the X and Y directions in the figure. As a result, the processing tool 22 can be placed at any position within the area. In a state in which each arm extends from the main body 1 to the maximum, that is, in a state in which the work head 13 is located at one position in FIG. 2, the four arms are positioned by each servo motor so as to form a substantially rhombic shape. The angle formed by the upper tip connecting arm 9a and the lower tip connecting arm 9b, which is the inner acute angle of this inner angle, is about 23 degrees, which allows the movable movement of the arm to be ensured in a wide range, and thus the above-mentioned. The area surrounded by the chain double-dashed line can be efficiently secured.

Further, in addition to such a symmetrical structure, each arm is made of iron having a coefficient of thermal expansion lower than that of aluminum or cast iron, so that the influence of heat from the servomotor or the like is suppressed as much as possible and the positional accuracy is improved. Can be improved. When the processing tool 22 is arranged at a position suitable for processing the work W, each servo motor holds each arm at a predetermined position by fixing the movement in the rotation direction by a brake (not shown) or the like. The machining motor 19 of the vertical movement unit 13 is rotated, and thereby the machining tool 22 is rotated via the drive shaft 20. Further, the servo motor 14 is rotated to rotate the ball screw nut 23. As a result, the slider 16 moves in the Z direction, that is, in FIG.
Move up and down. As a result, the rotating machining tool 22 is brought into contact with the work W to start perforation. By continuing this drilling operation for a predetermined time, a hole having a predetermined depth is drilled.

At this time, a processing reaction force F due to the drilling is generated in the Z direction, that is, in the vertical direction in FIG. As a result, the robot body receives the moment M. In the robot of this embodiment, the moment M
Therefore, it is possible to prevent bending of the arm due to the moment M and movement of the tip of the processing tool 22 as much as possible.

The above-mentioned servomotors 3a and 3b are
Since they are attached to each column or arm from above, they can be left attached for maintenance, and even in the worst case, the motor can be easily removed and replaced. can do. Further, as shown in FIG. 3, the cross-row bearings 30 and 31 which have a large rigidity and are easy to assemble are used for the connection between the connecting arms, and the span l between these bearings is further lengthened to increase the rigidity.

In the present embodiment, the working head 11 is provided with the perforating head, but the present invention is not limited to this, and since it is used for work such as supply of a work, a rotation drive unit capable of finite rotation for attitude control is provided. You may use. Further, if a hand part is separately attached to the tip of the punching work head, it is possible to perform the punching by supplying the work with a robot.

Further, in the present embodiment, the workpiece is fixed at an arbitrary position in the operation area of the robot to be perforated, but the robot holds the workpiece and the workpiece is placed at the arbitrary position. It is also possible to press it against a machine for processing. When the control box 30 of the present invention is used, for example, when press-fitting a work, the press-fitting amount and press-fitting amount are automatically checked in the control box, and when the servomotors 3a and 3b receive a large processing reaction force such as drilling. It is also possible to temporarily increase the gain and increase the motor power.

Further, in the robot of the present invention, as shown in FIG. 4, the other installation surface 1b of the column 1 is installed and the four connecting arms 7a, 7b, 9a, 9b are used as vertical surfaces in the vertical direction in the drawing. It is also possible to install the device so that it operates above and the vertical moving unit 13 operates on a horizontal plane. In the above embodiment, the upper rotary shaft 5a corresponding to the first rotary joint and the lower rotary shaft 5b serving as the second rotary joint are arranged coaxially with the column 1, but they are arranged in a shifted state. It is also possible to do so. In this case, the four arms form a five-bar link structure including the column body.

Further, the same effect can be obtained even if the lower base end connecting arm which is the second turning node is provided in the middle of the upper base end connecting arm. Also, the connecting shaft 11
Can be provided in the middle of any one of the upper tip connecting arm or the lower tip connecting arm, it is possible to obtain a link structure having the same effect.

The present invention is not limited to the above-mentioned embodiments, and various embodiments are included without departing from the gist of the present invention. For example, the present invention can be applied not only to a processing robot that performs punching and the like, but also to a working robot such as an assembly that causes a load on a working unit.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an industrial robot according to an embodiment of the present invention.

FIG. 2 is a diagram showing a moving area of the industrial robot in the embodiment of the present invention.

FIG. 3 is a diagram showing a mounting state of a drive motor and a coupling state between connecting arms.

FIG. 4 is a diagram showing a state in which the robot of the present invention is used by being horizontally mounted.

FIG. 5 is a detailed vertical sectional view of the vicinity of a first rotation node.

FIG. 6 is a detailed vertical sectional view of a working head 11.

[Explanation of symbols]

 1 column 3a, 3b, 14 servo motors 4a, 4b reducer 5a upper rotary shaft 5b lower rotary shaft 7a upper base end connecting arm 7b lower base end connecting arm 8a, 8b pivot 9a upper end connecting arm 9b lower end connecting arm 10 connection Axis 11 Work head 19 Processing motor 30 Control box W Work

Claims (11)

[Claims] 1. A main body having a first rotary joint and a second rotary joint, and one end attached to the first rotary joint and rotated by a first prime mover parallel to a plane. A first connecting arm, a second connecting arm having one end attached to the second rotating node and rotated in parallel to the plane, and provided on the first and second connecting arms, respectively. Third and fourth rotation nodes, third and fourth connection arms that are connected to the third and fourth rotation nodes such that one ends thereof are rotatable, and are rotated in parallel to the plane. A second prime mover that relatively rotationally drives the third connecting arm with respect to the first connecting arm, and a fifth rotating node that connects the third and fourth connecting arms are provided. It is provided on any one of the fourth connecting arms, and faces the plane. An industrial robot having a work head portion that receives a work reaction force in a substantially vertical direction. 2. The industrial robot according to claim 1, wherein the work head portion is provided on the third connecting arm. 3. The industrial robot according to claim 1, wherein the first connecting arm and the third arm are located above the installation surface. 4. The industrial robot according to claim 1, wherein the first rotation node and the second rotation node are arranged coaxially. 5. The industrial robot according to claim 1, wherein the third and fourth rotation nodes are provided at free ends of the first and second connecting arms, respectively. 6. The industrial robot according to claim 1, wherein the fifth rotation node is provided at free ends of the third and fourth connecting arms. 7. The industrial robot according to claim 1, wherein the distances between the turning nodes of the arms of the first to fourth connecting arms are the same. 8. The industrial robot according to claim 1, wherein the first to fourth connecting arms are made of a material having a thermal expansion coefficient smaller than that of aluminum. 9. The first and second connecting arms are provided inside the main body supporting portions that respectively support the first and second rotation nodes of the main body, and the first and second connecting arms are provided.
And the third and fourth connecting arms are provided inside the second and second connecting arms, respectively, and the cross-sectional area of the first or second connecting arm is made larger than the cross-sectional area of the third or fourth connecting arm. The industrial robot according to claim 1. 10. The body has a U-shape, and the first body
The industrial robot according to claim 1, wherein the second connecting arm and the second connecting arm are rotatably supported inward of the U-shaped body. 11. A body, a first connecting arm having one end attached to a first rotary node provided on the body, and a first prime mover for rotating the first connecting arm parallel to a plane. A second connecting arm having one end attached to the rotating node and being rotated in parallel to the plane; and third and fourth rotating nodes provided on the first and second connecting arms, respectively. One end of the third and fourth rotation nodes is rotatably coupled to the third and fourth rotation arms, and the third and fourth connection arms are rotated parallel to the plane. A second prime mover that relatively drives the three connecting arms to rotate, and a fifth rotating node that connects the third and fourth connecting arms, and one of the third and fourth connecting arms. Is installed in the An industrial robot having a receiving work head part, wherein the main body is formed with an installation surface parallel to the plane and an installation surface perpendicular to the plane.