JPS624473Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a work unit that is attached to the tip of a work arm of a versatile industrial robot that is used when performing assembly work for high-mix, low-volume production.

Recently, this kind of highly versatile industrial robots have been attracting attention, but as the use of industrial robots increases, various tasks such as screw tightening, box packing, etc. tools are being developed. With the development of this type of work tool, there is a demand for the development of a work unit to which the work tool can be attached in order to further increase the versatility of industrial robots. Among these, there is a need for the development of a work unit that can arbitrarily change the height of the tip of a power tool in accordance with the height of each work position, even if the height is different.

This invention was created in view of the above requests.
Examples will be described below with reference to the drawings. In FIGS. 1 to 3, reference numeral 1 denotes an articulated industrial robot, in which a first arm 4 is rotatably supported by a support 3 screwed onto a fixed base 2 via a bearing. A first spacer 5 is attached to the first arm 4 so as to surround the support column 3, and
A first motor 6 is fixed to the spacer 5 with its drive shaft 7a facing downward. A step is bored inside the upper part of the first spacer 5, and a circular spline 8a is fixed to this step, and this circular spline 8a is connected to a flex spline 9a fixed to the upper end of the support 3. It meshes with a part of the The flex spline 9a is configured to elastically deform and change its meshing position in response to the rotation of a non-circular wave generator 10a fixed to the drive shaft 7 of the first motor 6. An elastic deformation spline type speed reducer 11a is configured together with the wave generator 10a and the circular spline 8a. A stopper 12 is fixed to the column 3 at a position below the first arm 4, and a pin 13 attached to the base of the first arm 4 comes into contact with this stopper 12, so that the rotation of the first arm 4 is controlled in a predetermined manner. The angle is mechanically limited and a limit switch (not shown) is configured to electrically limit the angle. Further, a two-stage toothed pulley 14a is rotatably attached below this stopper 12, and the first toothed pulley 16 of the first pulse motor 15 fixed to the column 3 and this two-stage toothed pulley 14a A first toothed belt 17 is wound between the lower stage and the lower stage. the first pulse motor 15, the first toothed pulley 16,
Two-stage pulley 14a, two-stage toothed pulley 1 to be described later
4b, second toothed pulley 18, first toothed belt 1
7. It is configured so that the posture of the working tool, which will be described later, is controlled by a second toothed belt 24 and a third toothed belt 44, which will be described later.

A cylindrical portion is provided at the other end of the first arm, and a rotary shaft 20 that rotates integrally with the second arm 19 is rotatably held in this cylindrical portion. A notch 21 is provided so that the two arms 19 can pivot. A second spacer 22 is further attached to the upper side of this cylindrical portion, and a second motor 23 is attached thereto, and like the first motor 6, this second motor 23 is attached with its drive shaft 7b facing downward. . Further, the second spacer 22 has a step formed inside the upper part like the first spacer 5, and a circular spline 8 is formed in this step.
b is fixed. On the other hand, the second motor 23
A non-circular wave generator 10b is fixed to the drive shaft 7b of the wave generator 1.
A flex spline 9b is fixed to the upper end of the rotary shaft 20 so as to wrap around the rotary shaft 20. The rotation of the wave generator 10b causes the flex spline 9b to be elastically deformed and a portion thereof meshes with the circular spline 8b, so that the rotation of the second motor 23 is decelerated to a constant ratio and transmitted to the rotating shaft 20. The wave generator 10b, the circular spline 8b and the flex spline 9b constitute an elastically deformable spline type speed reducer 11b.

Further, the rotating shaft 20 is disposed to pass through the cylindrical portion of the first arm 4, and a two-stage toothed pulley 14b is attached to the lower end thereof. The upper stage of this two-stage toothed pulley 14b and the two-stage toothed pulley 14a
A second toothed belt 24 is wound between the second toothed belt 24 and the upper stage of the first pulse motor 15, and the rotation of the first pulse motor 15 is transmitted to the two-stage toothed pulley 14b.

Next, the main parts of the present invention will be explained. In FIG. 4, a housing 26 of a working unit 25 is fixed to the other end of the second arm 19. A second pulse motor 2 is mounted on the upper part of this housing 6.
7 is fixed with its drive shaft 7c facing downward via a third spacer 28, and the drive shaft 7c is rotatably held in the housing 26 via a first gear 29 and a second gear 30. A screw shaft 31 is connected. Two opposing change nuts 32a and 32b are screwed into the screw shaft 31, and the upper change nut 32a is fixed to a slide block 34 arranged to contain it, and the lower change nut 32b is This slide block 3
The slide block 34 is slidably locked on a locking pin 35 fixed to the screw shaft 35, and is configured to move up and down as the screw shaft 35 rotates. Further, the chain nuts 32a, 32
A spring 33 is disposed between the upper change nut 32a and the ball (not shown) built in the upper change nut 32a above the screw groove surface of the screw shaft 31, and the ball (not shown) built in the lower change nut 32b. (Please show) on the screw shaft 31.
It is configured to tightly fit below the thread groove surface to prevent crushing.

On the other hand, an upper bearing 40 and a lower bearing 41 are rotatably held in the housing 26, and a plurality of protrusions 42 are provided at equal intervals.
A spline shaft 39 having a spline shaft 39 is located parallel to the screw shaft 31 and is held so as to be able to move up and down. This spline shaft 39
A fixing ring 43 that moves together with the slide block 34 is fixed thereto, and the fixing ring 43 is rotatably held by the slide block 34 and is configured to rise and fall together with the rise and fall of the slide block 34. A chuck unit 45 of a power tool is fixed to the lower end of the spline shaft 3a, and is configured to be operated by air sent through an air hole 46 passing through the axis of the spline shaft 39. Further, a second toothed pulley 18 is fixed to the lower bearing 41, and a two-stage toothed pulley 1 is attached to the lower end of the rotating shaft 20.
A third toothed belt 44 is wound between the third toothed belt 4b and the lower stage of the belt 4b. Furthermore, a proximity switch 47 for detecting the upper limit of the slide block 34 is attached to the upper part of the housing 26, and is configured to detect when the slide block 34 returns to the upward position.

A ratchet 36 is fixed to the lower end of the screw shaft 31.
A pawl 37 is arranged so as to mesh with the pawl 37. This pawl 37 is connected to a rod of a cylinder 38 fixed to the lower end of the housing 26, and the pawl 37 is configured to be disengaged from the ratchet 36 when the rod is retracted by actuation of the cylinder 38. There is. Furthermore, this cylinder 38 is connected to an air circuit configured to operate at the same time as the power is turned on, and the rod is configured to retreat when the cylinder 38 operates.

In the industrial robot mentioned above, when the control device is powered on before starting work, the air circuit is activated.
Cylinder 38 is activated. When the rod of the cylinder 38 is retracted, the pawl 37 fixed thereto is disengaged from the ratchet 36. At this time, since power has already been supplied to the second pulse motor 27, the screw shaft 31 is restrained by an extremely large stopping torque, and the slide block 34 is held at its original position without falling. After that, the first motor 6
Then, the second motor 23 is driven to determine the working position of the chuck unit 45 on a plane, and this is stored in a control device (not shown). At the same time, the first pulse motor 15 is driven to determine the posture of the chuck unit 45 at each work position, and the second pulse motor 27 is driven to determine the height position at each work position, which is memorized. do.

When the work start switch (not shown) is turned on,
The first motor 6 and the second motor 23 rotate at a predetermined number of revolutions, and the chuck unit 45 is positioned at a predetermined position on a preset plane.

At the same time, a predetermined pulse is supplied to the second pulse motor 27 to shift the first gear 29 and the second gear 3.
0, the screw shaft 31 is rotated a predetermined number of revolutions. Along with this, the change nuts 32a and 32b move a predetermined distance along the screw shaft 31, so that the slide block 34
also move. At this time, the upper change nut 32
a is biased upward, and the lower chain nut 32b is biased downward by the spring, so that the balls built into the chain nuts 32a and 32b come into close contact with the upper and lower thread groove surfaces of the screw shaft 31, respectively. ni, change nut 32
a and 32b move. Therefore, even if there is a gap between the change nuts 32a, 32b and the screw shaft due to machining, the change nut 32
There is no backlash between a and 32b, and the slide block 34 integrated therewith can reliably descend a predetermined amount along the screw shaft.

As the slide block 34 is lowered, the spline shaft slides while being guided by the upper bearing 40 and the lower bearing 41 and stops at a predetermined position, and the chuck unit 45 at its lower end is positioned at a predetermined position. Even if the rotation of the second pulse motor 27 stops, the screw shaft 31 is restrained by an extremely large stopping torque because the second pulse motor 27 is still supplied with electric power. Even when weight is applied, the screw shaft 31 does not rotate. Thereafter, the chuck unit 45 is activated to perform a predetermined work at a predetermined work position.

After all the work is completed, the second pulse motor 27
At the same time, the air supply to the cylinder 38 is cut off, the pawl 37 engages with the ratchet 36, the rotation of the ratchet 36 is prevented, and the screw shaft 31 is held in that position. Therefore, the change nuts 32a, 32b, slide block 34, spline shaft 39 and chuck unit 45 are prevented from falling.

As explained above, the present invention has two change nuts arranged on a screw shaft that rotates under the rotation of a pulse motor placed at the tip of an arm, and one change nut is elastically connected to the other change nut. Each change nut is configured so that it is always in close contact with the upper and lower thread groove surfaces of the screw shaft, and a spline shaft is arranged so that it moves up and down together with this change nut, and the work is carried out at one end of this spline shaft. Since it is configured to mount a tool, it is possible to change the height of the tip of the tool at each working position as desired, and there is no bump between the change nut and the screw shaft, and the rotation of the screw shaft is prevented. The spline shaft is raised and lowered accurately according to the height of the workpiece, and the height position of the working tool can be adjusted extremely accurately.

Further, in the present invention, a ratchet is fixed to a screw shaft that allows a chain nut to move up and down as it moves with the work tool, a pawl is engaged with the ratchet, and the pawl is detached from the ratchet at the same time as the power is turned on. As a result, the power to the rotation drive source that rotates the screw shaft is cut off, and the screw shaft, which rotates in response to the rotation, becomes free, and the weight of the work tool applied to the change nut causes the screw shaft to rotate. Even if a force is applied in the direction of
There are advantages such as being able to prevent damage to the work tool or workpiece.

[Brief explanation of the drawing]

FIG. 1 is a front view of the present invention, and FIG. 2 is A of FIG.
FIG. 3 is a cross-sectional view of the main part of FIG. 1B.
FIG. 4 is a cross-sectional view of the main part of the present invention.
Support, 4...first arm, 5...first spacer,
6: first motor; 7a, 7b, 7c: drive shaft; 8a, 8b: circular spline; 9:
a, 9b... Flex spline, 10a, 10
b... Web generator, 11a, 11b...
Reducer, 12... stopper, 13... pin, 14
a, 14b: two-stage toothed pulley; 15: first pulse motor; 16: first toothed pulley; 17:
First toothed belt, 18 ... Second toothed pulley, 19
. . . second arm, 20... rotating shaft, 21... notch, 22... second spacer, 23... second motor, 24... second toothed belt, 25... working unit, 26... housing, 27... second pulse motor, 28... third spacer, 29... first gear, 30... second gear, 31... screw shaft, 32a, 32b... change nut, 33
...Spring, 34...Slide block, 35...
Locking pin, 36... ratchet, 37... pawl,
38: cylinder; 39: spline shaft; 40: upper bearing; 41: lower bearing; 42:
Protrusion, 43...fixing ring, 44...third toothed belt, 45...chuck unit, 46...air hole, 47...proximity switch.

Claims (1)

[Claims for Utility Model Registration] A housing 26 is fixed to the tip of the arm, a pulse motor 27 is attached to the upper part of the housing 26, and a screw shaft is attached to the housing 26 so as to be rotated by the rotation of the pulse motor 27. 31, and a change nut that moves up and down as the screw shaft 31 rotates is arranged, while a spline shaft 39 extending parallel to the screw shaft 31 is arranged in the housing 26 so as to be able to move up and down. A shaft 39 is configured to move up and down together with the chain nut, and this spline shaft 3
In the work unit of an industrial robot configured to control the height position of the work tool by attaching a work tool to one end of the screw shaft 31, two change nuts 32a, 32b are arranged on the screw shaft 31, and the change nuts 32a, 32b is fixed to the slide block 34, and the other is slidably arranged along the locking pin 35 implanted in the slide block 34, and a spring is inserted between the change nuts 32a and 32b to secure the screw. One of the change nuts 32a is arranged above the threaded groove surface of the shaft 31, and the other change nut 32b is arranged in close contact with the lower side of the groove surface, and the change nuts 32a, 3
2b is configured to move up and down along the screw shaft 31, while the screw shaft 3
1 protrudes from the housing 26, and a ratchet 36 is fixed to the lower end of the ratchet 36.
A pawl 37 that meshes with the housing 26 is fixed to a rod of a cylinder 38 fixed to the lower surface of the housing 26,
Furthermore, an air circuit is configured to operate the cylinder 38 at the same time as the power is turned on to retract the rod, so that the pawl 37 is separated from the ratchet 36 when the rod of the cylinder 38 is retracted. .