JPH042375B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Field> The present invention relates to a complex work device that automatically assembles parts.

<Prior Art> Conventionally, when performing multiple types of assembly operations such as gripping and transferring parts and tightening screws, each operation is performed using a dedicated work tool at a different work station.
In this case, not only does the work equipment become larger and require a large installation space, but it also takes time to transfer the parts to be assembled between each work station, which affects the efficiency of the assembly work. Ta.
Another problem was that equipment costs were becoming expensive.

<Purpose of the Invention> The present invention enables multiple types of assembly work to be performed at a single work station, reduces the size of work equipment, reduces equipment costs, and shortens work time, and solves the problems of the conventional art. .

<Structure of the Invention> In order to achieve the above object, the present invention provides a movable head that is indexable to a fixed head that is movable relative to the assembled parts, and a plurality of movable heads arranged at intervals in the indexing direction. A gripper that rotatably supports an input shaft of the input shaft, a screw tightening tool is provided at the tip of a spindle that is rotatably connected to one of the plurality of input shafts, and that is rotatably connected to one of the plurality of input shafts and grips an assembled part. A claw is provided on the movable head so that it can be opened and closed, and a shaft ring is provided on the rear end of the plurality of input shafts so as to be movable in the axial direction and engageable in the rotation direction, and a spring that urges the shaft motion ring to a retracted position. The movable head is provided with a rotation preventing member that engages with the shaft ring in the retracted position to prevent the shaft ring from rotating, and one of the plurality of input shafts moves the movable head to a working position corresponding to the assembled part. An indexing device for indexing is provided, and the output shaft is rotatably supported on the fixed head so as to be movable coaxially and rotatably with the input shaft indexed to the working position, and the input shaft and the output shaft are engaged with each other in the rotational direction. An engagement disengagement device is provided at the tip of the output shaft to form an engagement portion and move the output shaft forward and backward to a position where the output shaft engages with the engagement portion of the input shaft and a position where the output shaft does not engage. A push ring is attached to push down the shaft ring to a position where it does not engage with the rotation prevention member, and a rotation transmission means for transmitting the rotation of a servo motor installed on the fixed head to the output shaft is provided on the fixed head, and the rotation is transmitted. A torque detection mechanism for detecting rotational torque is provided in the middle of the means, a displacement detector is provided that is rotatably connected to the output shaft and detects the amount of rotation of the output shaft, and the opening/closing amount of the gripping claws is determined based on the signal from the displacement detector. and a control device that controls the force of gripping the assembly part by the gripping claws and the force of tightening the assembly part by the screw tightening tool based on the signal from the torque detection mechanism. It provides equipment.

<Examples> Examples of the present invention will be described below based on the drawings. In FIG. 1, reference numeral 1 denotes a fixed head, which is fixed to the end of a support shaft 2. This fixed head 1 can be moved and positioned in three dimensions by means of the support shaft 2 using a servo motor (not shown).

3 is a movable head rotatably attached to the fixed head 1. This movable head 3 has a worm wheel 4 fixedly attached to its outer circumference.
A worm 5 that meshes with a worm 5 provided on the fixed head 1 side and rotates by a motor (not shown)
This allows one of a plurality of types of work tools to be indexed to the index position A, which will be described later.

For example, one of the plurality of types of working tools provided on the movable head 3 is a component gripping tool 6, and the other one is a screw tightening tool 7. As shown in FIG. 2, these two tools 6 and 7 have a common configuration: an input shaft 19 rotatably supported on the movable head 3; and an engaging portion integrally formed at the rear end of the input shaft 19. 20, and an axial ring 21 which is fitted onto the outer periphery of the engaging part 20 so as to be slidable in the axial direction by spline engagement or the like, and which is pressed in the direction of the end surface of the engaging part 20 by a spring 22. , and a rotation preventing member 23 that engages with the shaft ring 21 to restrict the rotational phase of the input shaft 19.
The gripping tool 6 is provided with a gear 24 that is rotated by the input shaft 19, a plurality of operating shafts 25 that are rotated by the gear 24, and an arm 26 that is pivoted by the operating shaft 25. , and gripping claws 27 that contract and expand with respect to each other as the arm 26 pivots. In addition, in the screw tightening tool 7, the spindle 28b is spline-fitted into the sleeve 28a that is integrated with the input shaft 19, and a spring inside the sleeve 28a presses the spindle 28b in the extension direction to protrude from the sleeve 28a. At the tip of 28b is a hexagonal protrusion (screw tightening tool) 2 that fits into the hexagonal hole of the part.
9 is a protruding structure.

The drive mechanism for the gripping tool 6 or screw tightening tool 7 indexed to the indexed position A is as follows. A servo motor 8 is installed on the fixed head 1. A block 9 is fixedly installed at the location where the servo motor 8 is installed, and a drive shaft 10 coupled to the servo motor 8 is supported on the block 9. Further, the block 9 has an output shaft 11 whose axis is parallel to the drive shaft 10 and which is concentric with the input shaft 19 of the gripping tool 6 or the screw tightening tool 7 indexed at the index position A. It is supported on a shaft so that it can move forward and backward in the direction. This output shaft 11 is provided with a spline 12 on its outer periphery, and the driven gear 1 is attached to this spline 12.
3a is fitted. The rotation of the drive shaft 10 is transmitted to the output shaft 11 via the drive gear 13b, intermediate gear 13c, and driven gear 13a provided on the drive shaft 10. The drive gear 13b, intermediate gear 13c, and driven gear 13a constitute a rotation transmission means for transmitting the rotation of the servo motor 8 to the output shaft 11. A driving piece (engaging portion) 14 is provided at the tip of the output shaft 11, and is engaged in the rotational direction with an engaging portion 20 at the rear end of the input shaft 19, but is not engaged when the output shaft 11 is in the retracted position. It has a push ring 16 on its outer periphery that comes into contact with a shaft ring 21 provided on the outer periphery of the engaging portion 20 . Further, the output shaft 11 is constantly pressed by a spring 15 in the direction in which the driving piece 14 engages with the engaging part 20, and the driving piece 14 is pushed away from the engaging part 20 against the pressing force of the spring 15. As a means of liberation,
Solenoid 1 is attached to block 9 at the rear end of output shaft 11.
7 is provided, the operating shaft 18 of which is provided with an engagement/disengagement device connected to the rear end of the output shaft 11.

Further, a displacement detector 30 and a torque detection mechanism 31 are provided on the rotational power transmission path on the servo motor 8 side, that is, on the drive shaft 10. As shown in FIG. 2, the torque detection mechanism 31 includes a strain tube 32 mounted on the drive shaft 10, a strain gauge 33 attached to the strain tube 32, and a detection signal from the strain gauge 33 sent to the slip ring mechanism 34. It is constructed so that it can be taken out to the outside.

Based on the displacement detection signal from the displacement detector 30 and the torque detection signal from the torque detection mechanism 31, the gripping tool 6 controls the movement amount of the gripping claws 27 and the grip confirmation, and the screw tightening tool 7 controls the tightening force. It has a control device that performs control to perform confirmation. This control device has a control circuit configuration shown in FIG. 3 built into the numerical control device 41 shown in FIG. That is, in FIG. 3, the control device main body 35, the AD converter 36 that inputs the torque detection signal _S1 to the control device main body 35, and the control device main body 3
A deviation counter 37 inputs the command pulse from 5 and the pulsed displacement detection signal _S2 and calculates the deviation of the number of these pulses, and the output of the deviation counter 37.
A DA converter 38 that performs DA conversion, inputs a part of the torque detection signal S ₁ , and also inputs a part of the torque detection signal S1, and
Input the torque setting data and start signal from
A screw tightening control circuit 39 that outputs a rotation command signal according to a predetermined torque pattern, and the DA converter 3
8 and a screw tightening control circuit 39, and outputs an output signal from either one as a drive signal _S3 according to a command from the control device main body 35.

The control device main body 35 has a screw tightening mode and a gripping mode, and in the screw tightening mode, it outputs torque data according to the screw tightening mode and starts the operation. In addition, the screw tightening control circuit 39
outputs a specified voltage in a predetermined pattern until the commanded predetermined torque is reached. moreover,
In the gripping mode, pulse distribution is performed according to the amount of movement (contraction, expansion) of the gripping claws 27, and gripping is confirmed using torque and pulse distribution is interrupted. In Fig. 1, 42 is a drive signal.
This is a drive unit that operates the servo motor 8 based on _S3 .

Next, the operation of the apparatus of the present invention will be explained.
In FIG. 1, A is the indexing position of the gripping tool 6 or screw tightening tool 7 as described above, and B is the avoidance position. The gripping tool 6 is now indexed at index position A in FIG. The gripping tool 6 indexed at this indexed position A has the drive piece 14 at the tip of the output shaft 11 engaged with the engagement portion 20 at the rear end of the output shaft 19 by the pressing force of the spring 15, and at the same time The pushing ring 16 pushes the pivoting ring 21 into the spring 22.
The input shaft 19 is pushed against the pressing force to release the engagement with the rotation prevention member 23 and allow rotation of the input shaft 19. Therefore, the forward and reverse rotations of the servo motor 8 are transmitted to the input shaft 19 via the drive shaft 10 and the output shaft 11, and the gripping claws 27 are contracted to grip a component or expanded to release the grip. It is. Here, when contracting for gripping a component, the control device main body 35 distributes a command pulse at a rapid traverse speed to the deviation counter 37, whereby the gripping claws 27 are contracted at a rapid traverse from the expanded state, and the amount of displacement thereof is reduced. It is detected by the displacement detector 30 and fed back to the deviation counter 37. As a result, the gripping claws 27 are moved at a desired rapid feed speed, and just before gripping the component, the distribution speed of the command pulse is reduced to control slow feed. This is because if the component is gripped in rapid motion, the gripping claws 27 may come into sudden contact with the component, potentially causing dents.
When the gripping claws 27 that have been converted to slow feed grip the component, a torque fluctuation occurs on the drive shaft 10, which is detected by the torque detection mechanism 31 to confirm gripping and end the distribution of command pulses, thereby controlling the servo control. Stop motor 8. Thereafter, the fixed head 1 is moved together with the movable head 3 via the support shaft 2 to transfer the parts to the work station. The displacement detector 30 also detects whether the grip is released after the component is transferred.

Next, when performing the screw tightening work of the transferred component, the screw tightening tool 7 located at the avoidance position B is indexed to the index position A. Prior to this indexing operation, it is necessary to disconnect the input shaft 11 of the gripping tool 6 from the output shaft 11 on the fixed head 1 side. For this purpose, the solenoid 17 is activated, and the output shaft 11 is moved backward by the operating shaft 18 against the pressing force of the spring 15. As a result, the driving piece 14 disengages from the engaging portion 20, and at the same time, the pushing ring 16 releases the pushing of the axial ring 21, and the axial ring 21 is returned to its original position by the spring 22. It returns and engages with the rotation prevention member 23, thereby restraining the input shaft 19 in the phase state in which rotation is stopped.

When the driving piece 14 and the engaging portion 20 are disengaged from each other, the movable head 3 becomes indexable and rotatable, and the worm 5
Then, the movable head 3 is rotated by the worm wheel 4 to index the screw tightening tool 7 to the index position A. After that, when the solenoid 17 is deactivated, the output shaft 11 is moved by the pressing force of the spring 15.
moves in the forward axis, and the driving piece 14 engages with the engaging portion 20 of the input shaft 19 of the screw tightening tool 7, and at the same time the pushing ring 16 pushes the axial moving ring 21 against the pressing force of the spring 22. The engagement with the rotation prevention member 23 is released. Then, the fixed head 1 is operated to fit the hexagonal protrusion 29 at the tip of the spindle 28b into the hexagonal hole of the work station component, and the servo motor 8 is activated to rotate the spindle 28b to perform screw tightening work. be. In this case, unlike the gripping tool 6, there is no need to detect and control the displacement of the contraction movement of the gripping claws 27, and when a predetermined screw tightening torque is reached, the torque detection mechanism 31 detects and controls the servo. It controls the stop of the motor 8.

Although the movable head in the illustrated example has a turret-type rotating indexing structure, it is also possible to use a structure in which one of multiple types of work tools is indexed and positioned on the output axis by direct movement relative to the fixed head. The invention is applied.

<Effects> As described above, according to the device of the present invention, it is possible to assemble many types of parts at a single work station using the necessary work tools, and it is possible to assemble parts between different work stations unlike in the past. It eliminates the need to transfer attached parts, significantly shortens assembly time, and improves work efficiency.

In addition, since the drive servo motor, torque detection mechanism, and displacement detection mechanism for multiple types of work tools are all common, the structure can be significantly simplified and downsized, reducing installation space and equipment costs. This has the advantage of reducing the amount of water used. When the axial ring is not pushed by the push ring, the axial ring is moved backward by the spring, and the axial ring is stopped from rotating by the rotation prevention member, so that the gripping Even if the connection between the claws and the displacement detector is released, the opening and closing positions of the gripping claws can be accurately controlled by the displacement detector and the control device.

[Brief explanation of drawings]

FIG. 1 is a sectional view of the device of the present invention, FIG. 2 is a detailed sectional view of the coupling portion between the output shaft and the input shaft, and FIG. 3 is a block diagram of the control circuit configuration. 1... Fixed head, 3... Movable head, 6...
Gripping tool, 7... Screw tightening tool, 8... Servo motor, 10... Drive shaft, 11... Output shaft, 14...
... Drive piece, 17 ... Solenoid, 19 ... Input shaft, 20 ... Engagement part, 27 ... Gripping claw, 28b ...
... spindle, 29 ... hexagonal projection, 30 ... displacement detector, 31 ... torque detection mechanism, 35 ... control device main body, 41 ... numerical control device.

Claims (1)

[Claims] 1. A movable head is provided in an indexable manner on a fixed head that is movable relative to the assembled parts, a plurality of input shafts are rotatably supported on the movable head at intervals in the indexing direction, and one of the plurality of input shafts is rotatably supported on the movable head at intervals in the indexing direction. A screw tightening tool is provided at the tip of a spindle that is rotatably connected to one of the input shafts, and a gripping claw that is rotatably connected to one of the plurality of input shafts and grips the assembled parts is provided on the movable head so that it can be opened and closed. A shaft ring is provided at the end so as to be movable in the axial direction and engageable in the rotational direction, and a spring is provided to urge the shaft ring to the retracted position, and the spring engages with the shaft ring in the retracted position to rotate the shaft. The movable head is provided with a rotation preventing member that prevents the moving ring from rotating, an indexing device is provided that indexes the movable head to a working position where one of the plurality of input shafts corresponds to the assembled part, and the output shaft is moved to the working position on the fixed head. The input shaft is movably and rotatably supported in the coaxial direction with respect to the input shaft, the input shaft and the output shaft are each formed with an engaging part that engages with each other in the rotational direction, and the output shaft is connected to the engaging part of the input shaft. An engagement/disengagement device is provided at the tip of the output shaft to advance and retreat to a position where it engages and a position where it does not engage, and a pushing motion is provided at the tip of the output shaft to push down the shaft ring to a position where it does not engage with the detent member. A ring is attached, a rotation transmission means for transmitting the rotation of a servo motor installed on the fixed head to the output shaft is provided on the fixed head, a torque detection mechanism for detecting rotational torque is provided in the middle of this rotation transmission means, and an output A displacement detector is provided that is rotationally connected to the shaft and detects the amount of rotation of the output shaft, and the opening/closing amount of the gripping claws is controlled based on the signal from the displacement detector, and the amount of opening/closing of the gripping claws is controlled based on the signal from the torque detection mechanism. A compound work device comprising a control device for controlling the force of gripping the assembled part by the screw tightening tool and the force of tightening the assembled part by the screw tightening tool.