JPH0113979B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a precision movement device using a step motor and a wire, which allows a member driven by a step motor to be moved quickly and with high precision via a wire. Note that the wire here includes various conductive conditions such as strings and belts.

PRIOR ART Such a moving device is widely used for moving a component holding head in an automatic component mounting device, or a printing head in an XY plotter or printer.

1 and 2 show an example of an automatic component mounting device to which the present invention is applied, in which chip-shaped electronic components fed by a component feeding device are moved in the X-axis and Y-axis directions perpendicular to each other. After being held in a moving head, it is automatically mounted on a predetermined position on a printed circuit board.

In the figure, a guide table 2 constituting a second guide part is provided slidably in the X-axis direction along a first guide part (not shown) provided inside the device main body 1. A head 3 is mounted so as to be slidable in the Y-axis direction perpendicular to the X-axis in a horizontal plane.

A controller C is provided separately from the main body 1 of the apparatus, and commands from the controller C control the step motor that drives the guide table 2 and the step motor that directly drives the head 3, thereby moving the head 3 along the X axis. and the required amount of movement in the Y-axis direction.

A component holder 5 is attached to the head 3, which attracts components using negative pressure supplied from a negative pressure supply pipe 4. It moves up and down in the Z-axis direction perpendicular to the axis.

On the other hand, as shown in FIG. 2, various parts supply devices 7 such as a linear chip feeder and a tape feeder are provided on the top surface of the main body 1 of the apparatus. Chip-shaped electronic components such as capacitors, resistors, diodes, and transistors are suction-held by the component holder 5 and moved three-dimensionally along the X, Y, and Z axes. After being mounted at a predetermined position on a printed circuit board mounted and fixed on the mounting base 8, it is fixed through post-processes such as heat treatment.

In the automatic component mounting device having the above configuration, conventionally, a third drive device is used as a drive device for driving the guide table 2 on which the head 3 is attached in the X-axis direction.
The one shown in the figure is used.

The annular wire 9 surrounds four guide rollers 10 provided inside the device main body 1, and its long side is
It is stretched in a rectangular shape oriented in the axial direction, and both ends thereof are connected to the guide table 2 on the upper long side.

A drive pulley 13 is provided on the lower long side of the wire 9 and is rotatably driven by a step motor 11 for moving the guide table via a timing belt 12. A portion of the wire 9 is wound around the drive pulley 13 a plurality of times. It's being passed around. Therefore, when the step motor 11 is rotated by a predetermined angle in response to a command from the controller C shown in FIG.

The movement of the head 3 in the Y-axis direction along the longitudinal direction of the guide table 2 is also driven by a similar step motor and wire.

However, in such a conventional moving device using a step motor and wire, in order to increase the moving speed of the head 3 in order to improve work efficiency, it is necessary to
Either the frequency of the pulses supplied to the step motor can be increased, or the rotation angle per pulse of the step motor can be increased.

However, in the former case, since there is an upper limit to the characteristics of the step motor, a step motor with a large rotation angle per pulse is usually used. the result,
This method has drawbacks such as the positioning accuracy of the head 3 becomes rough and it becomes difficult to solder a precision printed circuit board.

Purpose This invention was made in view of the above points,
It is an object of the present invention to provide a precision movement device using a step motor and a wire that can move quickly and with high precision with a simple configuration.

Configuration Therefore, the precision movement device using a step motor and a wire according to the present invention includes a correction step motor that is separate from the step motor that moves the wire along the longitudinal direction, and a correction step motor that is driven by the correction step motor to adjust the span of the wire. engages the middle part;
By providing a tension pulley that bends the wire against the tension, the member connected between both ends of the wire can be slightly moved.

Embodiment Hereinafter, an embodiment in which the present invention is applied to a guide table moving device of an automatic component mounting device will be described with reference to FIGS. 4 and 5 of the accompanying drawings.

In these figures, parts corresponding to those in FIG. 3 are designated by the same reference numerals.

In FIG. 4, a correction step motor 14 is provided separately from the step motor 11 that moves the wire 9 in the longitudinal direction, and a rotating circle is driven to reciprocate by the correction step motor 14 via a timing belt 15. A tension pulley 17 is provided on the plate 16 eccentrically from the center of rotation, and the tension pulley 17 can be freely engaged and detached from the middle of the span of the wire 9 stretched between the drive pulley 13 and the guide roller 10' adjacent thereto. Nasu.

Furthermore, with respect to the drive pulley 13, the eccentric pulley 1
One end of the wire 9 opposite to the guide table 2
A spring 18 is engaged between the wires 9 and 9 to apply initial tension to the wire 9 to eliminate deflection between each span.

In the precision movement device using the step motor and wire configured as described above, the tension pulley 1
When the correction step motor 14 rotates from the position shown in solid lines in FIG. resists the tension and is bent to the state shown by the imaginary line.

Here, if there is no slippage between the wire 9 and the drive pulley 13, the guide table 2 connected to one end of the wire 9 will be moved by the compression of the spring 18 and the expansion of the wire 9 within its elastic limit. Move to the left to the position shown by the imaginary line in FIG. That is, from the position driven by the rotation of the step motor 11, it can be further moved slightly by the rotation of the correction step motor 14.

Now, the fine movement amount of the guide table 2 is Δl, the deviation amount of the wire 9 from the reference position is dl, and the drive pulley 13
The length of wire 9 from to guide table 2 is L
Then, the following relationship holds true: Δl=k・dl/L (k: constant).

That is, the fine movement amount Δl of the guide table 2 is proportional to the deviation amount dl of the wire 9 from the reference position, and inversely proportional to the length L of the wire. Further, the amount of deviation dl is related to the rotation angle of the rotating disk 16.

Therefore, the amount of error between the movement position of the guide table 2 by the step motor 11 and the position on the printed circuit board where the electronic component is actually mounted, and the pulse of the correction step motor that is rotated to correct this amount of error. The actual value is measured in advance for each position of each electronic component, and the value is stored in the computer of the controller C. Each time the component is mounted, the controller C commands the step motor 11. If the correction step motor 14 is rotated by a required amount along with the rotation of the electronic component mounting position, precise positioning of the electronic component mounting position becomes possible.

In this embodiment, the tension pulley 17 is provided at an eccentric position of the rotating disk 16 driven by the correction step motor 14, but a cam is provided on the rotating disk 16, and a lever driven by this cam is provided. A tension pulley may be provided in the wire 9, etc., and the tension pulley 10 may be in constant contact with the wire 9 instead of being able to be freely engaged with and detached from the wire 9, and the contact portion is not limited to the position in the above embodiment. do not have.

Further, in the above embodiment, the amount of fine movement of the guide table 2 is absorbed by the sum of the amount of extension of the spring 18 and the wire 9, but when the amount of fine movement of the guide table 2 is within the elastic limit of the wire expansion and contraction. , spring 1
8 is not necessarily necessary, and the above-mentioned fine movement amount can be absorbed only by the expansion and contraction of the wire 9 itself.

Furthermore, it goes without saying that the present invention is not limited to automatic component mounting devices, but can be applied to any device having a similar moving mechanism using a step motor and wire.

Effects As described above, according to the present invention, in a precision movement device using a step motor and a wire,
A correction step motor that is separate from the step motor that drives the wire, and a tension pulley that is driven by the correction step motor and engages with the mid-span of the wire and bends the wire against the tension. As a result, even if the pitch of the member stopping position by the wire driving step motor is made coarse, the stopping position can be finely corrected by rotating the correction step motor and bending the wire. It has an excellent effect of enabling high-precision movement.

[Brief explanation of drawings]

FIG. 1 is a front view showing an example of an automatic component mounting device to which the present invention is applied, FIG. 2 is a plan view thereof, and FIG. 3 is a perspective view showing a conventional example of the guide table moving device. FIG. 4 is a perspective view showing an embodiment of the present invention, and FIG. 5 is an explanatory view showing the moving state of the same. 2... Guide table, 3... Head, 9...
Wire, 10... Guide roller, 11... Step motor, 13... Drive pulley, 14... Correction step motor, 17... Tension pulley, C...
…controller.

Claims (1)

[Claims] 1 The drive pulley driven by the step motor is
In an apparatus for moving a member connected between both ends of the wire by a required amount by winding and rotating a part of a wire stretched around a guide roller, the step motor and is characterized in that it is provided with a separate correction step motor and a tension pulley that is driven by the correction step motor and engages with the mid-span of the wire and bends the wire against the tension thereof. Precision movement device using step motor and wire.