JP3069941B2 - Power supply device at the wrist of the robot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wrist body pivotally supported on an end of a robot arm and rotatable about a rotation axis parallel to a longitudinal direction of the robot arm, and a wrist body supported on the wrist body. The present invention relates to a power supply device provided on a wrist of a two-axis structure including a tool holder rotatable about a rotation axis orthogonal to a rotation axis so as to supply power from a robot arm to work equipment mounted on the tool holder.

[0002]

2. Description of the Related Art Conventionally, as a power supply device of this kind, a first slip power supply joint is provided around a rotation axis of a wrist body according to Japanese Utility Model Laid-Open Publication No. Sho 62-109884.
2. Description of the Related Art It is known that a second slip power supply joint is provided around a rotation axis of a tool holder, and power is supplied to work equipment from a robot arm via a first slip power supply joint and a second slip power supply joint. The slip power supply joint is configured to slidably contact a power supply path provided on one member that relatively rotates and a power supply path provided on the other member via a contact that is biased by a spring so as to be relatively rotatable. .

[0003]

When the slip power supply joint is used as described above, the contacts of each power supply joint slide with respect to the power supply path when the wrist body and the tool holder rotate, and the contact and the power supply path slide. Dynamic wear causes the durability of the power supply joint to decrease, and the rotational load on the wrist body and tool holder increases due to the sliding resistance between the contact and the power supply path, resulting in a decrease in the operation speed of the wrist, The torsion of the rotation drive system of the unit causes a problem that the accuracy of the posture control of the work equipment is deteriorated. An object of the present invention is to provide a power supply device that solves such a problem.

[0004]

In order to achieve the above object,
The present invention provides a wrist body pivotally supported on an end of a robot arm and rotatable around a rotation axis parallel to the longitudinal direction of the robot arm, and a rotation orthogonal to the rotation axis, supported on the wrist body. A power supply device is provided on a wrist of a two-axis structure comprising a tool holder rotatable around an axis to supply power from a robot arm side to work equipment attached to the tool holder. A pressurized first power supply joint that allows a contact member to be connected to the provided power supply path to be detachable from a power supply path provided on the wrist body by a cylinder is provided, and a pressurized second power supply is provided on the rotation axis of the tool holder. the joint is provided, the second power supply joint is provided with a cylinder fixed on one side of the rotational axis of the tool holder, of the cylinder piston rod
Contact part connected to the power supply path provided on the wrist body
The materials are connected via a ball joint to reduce the
Moving by being configured to press the contact member from the rotational axis direction outside the feeding path of the tool holder side of the provided in the rotation axis direction outer side of the cylinder, the first
And the contact member of each of the second power supply joints is separated from the power supply path of the other party when the wrist body or the tool holder rotates.

[0005]

When the wrist body or the tool holder is rotated, the first and second rotations are performed.
The contact member of each of the power supply joints is separated from the power supply path of the other party to prevent sliding wear between the contact member and the power supply path of the other party, and also to prevent a load due to sliding resistance between the two. Then, after the work equipment is positioned in a predetermined posture by rotation with respect to the wrist body and the tool holder, the contact member of each power supply joint is pressed against the other power supply path to supply power to the work equipment. Since the drive shaft for the tool holder needs to be arranged on the rotation axis of the wrist body, the first power supply joint is arranged around the wrist body.

[0006]

Referring to FIGS. 1 to 3, reference numeral 1 denotes a jig unit for setting a work, and 2 denotes a ceiling frame provided above a portion where the jig unit 1 is disposed. A robot 3 is mounted, and a stud welding gun 4 is attached to the robot 3 to weld a workpiece.

The jig unit 1 comprises a pair of jigs 11, 11 mounted on a turntable 10, and the jigs 11, 11 are rotated by 180.degree. And the workpiece welding position on the back side can be turned alternately.

The ceiling frame 2 is supported by four columns 20, and the width between the columns 20 is made smaller than the width of the ceiling frame 2, so that the installation space can be reduced.

The robot 3 is configured such that the depth direction of the ceiling frame 2 is the X axis, the width direction is the Y axis, and the vertical direction is the Z axis.
A traveling frame 30 movably provided in the X-axis direction across the guide frames 21 on the beam members on both sides in the Y-axis direction;
Robot body 31 supported to be movable in the Y-axis direction at 0
And a robot arm 32 elongated in the Z-axis direction supported on a robot body 31 so as to be able to move up and down. A lower end of the robot arm 32 is provided around a vertical U-axis parallel to the longitudinal direction of the arm and a U-axis. Is provided with a wrist 33 having a biaxial structure rotatable about a horizontal V-axis perpendicular to the vertical axis. The stud welding gun 4 is attached to the wrist 33, and the jig 11 at the welding position
The upper workpiece can be welded from any direction by changing the posture of the stud welding gun 4 by the operation of the wrist 33.

The traveling frame 30 is slidably supported on a guide rail 30a on the guide frame 21 via a linear guide 30b, and is connected to an X-axis motor Mx mounted on one end of the traveling frame 30. The traveling frame 30 is driven in the X-axis direction by meshing the driving frame 30c with the rack 30d fixed to the guide frame 21. The robot body 31 is the traveling frame 30
A pinion 31c slidably supported by a pair of upper and lower guide rails 31a fixed via a linear guide 31b via a linear guide 31b and connected to a Y-axis motor My mounted on the front surface of the robot body 31 is attached to the traveling frame 30. Fixed rack 31d
And the robot body 31 is driven in the Y-axis direction. The robot arm 32 includes a cylindrical arm body 32a and a plate-shaped slide base 32b fixed to the arm body 32a.
2 is slidably supported by a pair of guide rails 32c fixed to the back surface of the slide base 32b on a linear guide 32d fixed to the front surface of the robot body 31, and is connected to a Z-axis motor Mz mounted on the back surface of the robot body 31. The pinion 32e to be connected is meshed with a rack 32f fixed to the back of the slide base 32b, and the robot arm 32
Are driven in the Z-axis direction.

As shown in FIGS. 4 and 5, the wrist portion 33 includes a wrist body 33b rotatably supported around the U axis via a bearing 33a at a lower end of an arm body 32a, and a lower end of the wrist body 33b. And a tool holder 33d rotatably supported around a V-axis via a bearing 33c. A U-axis motor Mu and a V-axis motor Mv are mounted on the upper end of the arm main body 32a, and a hollow drive driven by the U-axis motor Mu via a coaxial speed reducer 33e such as a cyclo speed reducer. The shaft 33f is connected to the arm body 32
a, and is connected to the wrist body 33b. The drive shaft 33g connected to the V-axis motor Mv is connected to the drive shaft 33f.
And the wrist body 33b, and the drive shaft is connected to the bevel gear 3
3h and the tool holder 33 via the coaxial speed reducer 33i
d, the wrist body 33b and the tool holder 33d are rotated around the U axis and the V axis by the U-axis motor Mu and the V-axis motor Mv, respectively.

A transformer 5 is provided on the side of the jig unit 1.
And a power supply joint 51 in which one output terminal of the transformer 5 is provided to the cable 50 and the jig unit 1.
And the other output terminal of the transformer 5 is connected to a power supply bar 53 fixed to the traveling frame 30 via a cable 52, and the power supply bar 53 is connected to the robot main body 31. Is connected to a power supply bar 56 fixed to the robot arm 32 via two power supply joints 54 and 55 provided on the wrist portion 3.
3 is connected to the stud welding gun 4 via the power supply device provided in the apparatus 3, and the work on the jig 11 is pressed by the welding gun 4 via the work between the welding gun 4 and the jig 11. Energization was performed to weld the work.

Power supply joints 51, 54, and 55 provided on the jig unit 1 and the robot body 31 are cylinders 51, respectively.
a, a pressurized joint having contact members 51b, 54b, 55b which are moved in and out of contact with each other by 55a, 55a.

The power supply device provided on the wrist portion 33 includes a first power supply joint 57 provided around the wrist body 33b for connecting the power supply bar 56, which is a power supply path on the robot arm 32 side, to a power supply path on the wrist body 33b side. And a second power supply joint 58 provided on the V axis, which is the rotation axis of the tool holder 33d, for connecting the power supply path on the wrist body 33b side to the power supply path on the tool holder 33d side.

The first power supply joint 57 is shown in FIGS.
As shown in FIG. 8, a contact member 57a connected to the power supply bar 56 is constituted by a pressurized joint which can be freely connected to and separated from a power supply path on the side of the wrist main body 33b by a cylinder 57c. To describe this in detail, in the present embodiment, a conductive ring 57b constituting a power supply path on the side of the wrist body 33b is fitted around the outer periphery of the wrist body 33b via an insulating material 57d, and is fitted on the conductive ring 57b in the diametrical direction. A contact member 57a and a cylinder 57c are provided for each pair so as to be contacted and separated from both sides. Each cylinder 57c is attached to each bracket 57e vertically disposed on the outer periphery of the lower end portion of the arm body 32a of the robot arm 32 at the both sides in the diametric direction, and a spherical joint 57g is attached to the tip of the piston rod 57f of each cylinder 57c. After mounting, each contact member 57c was connected to the joint 57g via an insulating material 57h. Thus, each contact member 57a is swingably connected to the piston rod 57f, and is reliably pressed against the peripheral surface of the conductive ring 57b by the extension operation of the cylinder 57c.

A pair of brackets 57i, 57i are fixed to the outer periphery of the lower end portion of the arm body 32a at a phase difference of 90 ° from the cylinder brackets 57e, 57e. A pair of tap portions 57j, 57j made of a long copper plate are
k, 57k, the two tap portions 57j, 57
j are positioned on both sides of the conductive ring 57b in the diameter direction orthogonal to the diameter direction. And the power supply bar 56
A pair of rigid conductors 56a, 56a
Are connected to both tap portions 57j, 57j through
Both ends of each contact member 57a are connected to both tap portions 5 via a pair of flexible conductors 571, 571 made of an ounce copper plate.
7j, 57j, so that power can be efficiently supplied from the power supply bar 56 to the conductive ring 57b via both contact members 57a, 57a. Second power supply joint 5
8, as shown in FIG. 5, it is positioned on the V axis to the outer surface of the tool holder 33d attached to the cylinder 58c, the front cover 58d of the cylinder 58c, the tool holder 33
The annular conductive plate 58b constituting the power supply path on the d side is
e, and a ball joint 58g was attached to the tip of the piston rod 58f of the cylinder 58c projecting from the front cover 58d, and the contact member 58a was connected to the joint 58g via an insulating material 58h. Thus, the contact member 58a is swingably connected to the piston rod 58f, and is reliably pressed against the outer surface of the annular conductive plate 58b by the contraction operation of the cylinder 58c.

The contact member 58a is provided with a terminal 58i extending upward, and the terminal 58i of the contact member 58a is turned on to a terminal 57m extending downward formed on the conductive ring 57b constituting the power supply path on the wrist main body 33b side. The stud welding gun 4 is connected to the flexible conductor 4a as shown in FIG. 1 by connecting via a flexible conductor 58j made of a copper plate and providing a terminal 58k extending downward on the annular conductive plate 58b. Connected through.

When changing the direction and posture of the stud welding gun 4 by rotating the wrist body 33b and the tool holder 33d , the contact member 57a of the first power supply joint 57 is used.
Is separated from the conductive ring 57b and the contact member 58a of the second power supply joint 58 is connected to the annular conductive plate 58.
Separate from b.

According to this, each contact member 57a,
Wear due to sliding between the contact member 58a and the mating member formed of the conductive ring 57b and the annular conductive plate 58b does not occur, the durability of each of the power supply joints 57 and 58 is improved, and furthermore, the distance between each contact member 58a and the mating member is increased. The wrist body 33b and the tool holder 33d can be rotated without receiving the sliding resistance of the stud, and the operation speed of the wrist 33 can be increased, and the rotation drive system of the wrist 33 can be prevented from being twisted. The accuracy of the attitude control of the welding gun 4 can be improved.

The embodiment in which the present invention is applied to the power supply device for the wrist 33 of the robot 3 to which the stud welding gun 4 is attached has been described above. However, the power supply device for the wrist portion of the robot for mounting work equipment other than the welding gun is described. The invention is also widely applicable.

[0021]

As is apparent from the above description, according to the present invention, since the first power supply joint for the wrist main body is arranged around the wrist main body, the drive shaft for the tool holder is connected to the rotating shaft of the wrist main body. Since the drive system of the tool holder can be arranged in a space-efficient manner by being inserted on the line, and the first power supply joint and the second power supply joint for the tool holder are both configured to be pressurized, the sliding of these power supply joints is achieved. The wrist can be operated without receiving any resistance, and the posture of the work equipment can be changed quickly and accurately, and the durability of the power supply joint can be improved.

[Brief description of the drawings]

FIG. 1 is a front view of an example of a robot equipped with the apparatus of the present invention.

FIG. 2 is a plan view thereof.

FIG. 3 is a side view thereof.

FIG. 4 is an enlarged sectional view taken along the line IV-IV of FIG. 1;

5 is an enlarged sectional view taken along line VV of FIG.

FIG. 6 is a front view of the first power supply joint as viewed from the direction of arrow VI in FIG. 4;

FIG. 7 is a sectional view taken along the line VII-VII of FIG. 6;

8 is a sectional view taken along the line VIII-VIII in FIG.

[Explanation of symbols]

 Reference Signs List 3 robot 32 robot arm 33 wrist 33b wrist main body 33d tool holder 4 stud welding gun (work equipment) 56 power supply bar (arm side power supply path) 57 first power supply joint 57a contact member 57b conductive ring (wrist body side power supply path) 57c Cylinder 58 Second power supply joint 58a Contact member 58b Annular conductive plate (tool holder side power supply path) 58c Cylinder

Continuation of the front page (56) References JP-A-4-319278 (JP, A) JP-A-5-123985 (JP, A) JP-A-5-138580 (JP, A) JP-A-4-135076 (JP , A) (58) Fields studied (Int. Cl. ⁷ , DB name) B25J 19/00 B23K 11/11 570

Claims (1)

(57) [Claims] 1. A wrist body pivotally supported on an end of a robot arm and rotatable around a rotation axis parallel to a longitudinal direction of the robot arm, and orthogonal to the rotation axis supported by the wrist body. A power supply device provided on a wrist of a two-axis structure comprising a tool holder rotatable around a rotation axis to supply power from a robot arm side to work equipment mounted on the tool holder, wherein a robot arm is provided around a wrist body. A pressurized first power supply joint that allows a contact member connected to the power supply path provided on the wrist body to be able to contact and separate with a power supply path provided on the wrist body, and a pressurized second power supply joint on the rotation axis of the tool holder. A power supply joint, wherein the second power supply joint includes a cylinder fixed to one side surface of the tool holder in the rotation axis direction ;
To the power supply path provided on the wrist body on the piston rod of the cylinder
Connect the contact members to be connected via ball joints
Te, by the contraction operation of the cylinder is configured to press the contact member from the rotational axis direction outside the feeding path of said rotary is provided axially outside surface tool holder side of the cylinder, said first and second A contact member of each of the power supply joints is separated from a power supply path of a partner when the wrist body or the tool holder is rotated.