JPS59138523A - Transfer control method for article to be conveyed by linear motor - Google Patents

Abstract

PURPOSE:To transfer an article to be conveyed at a prescribed speed without fine dust by driving and controlling a linear motor based on an output from a speed detecting means provided between the starting point and the final point on a conveying passage. CONSTITUTION:A conveying bench 6 is driven by a linear motor while being floated with compressed air and the bench 6 is conveyed without making contact with a conveying table 2. Then, plural linear motors and plural speed detecting means 15 are properly arranged between the starting point and the final point on a conveying passage. And, an inverter 17 is controlled by a control part 16 such that outputs having predetermined frequencies are supplied to the primary coils 4b of corresponding linear motors based on outputs from these speed detecting means. Hereby, the conveying bench 6 is slowly started at the starting point, transferred at a prescribed speed along the intermediate section, and slowly stopped at the final point.

Description

[Detailed Description of the Invention] G) Industrial Application Field This invention relates to a method for controlling the transfer of a conveyed object using a linear motor, and in particular, to a method for controlling the transfer of a conveyed object by a linear motor, and in particular, to drive the conveyed object by a linear motor while levitating the conveyed object with compressed air, so that the conveyed object reaches its destination. The present invention relates to a method for controlling the transfer of a conveyed object using a conveyor linear motor.

(B) Prior art Conventionally, as this type of conveyance device, there have been suspended endless trolley conveyors, etc., but these generate fine dust in the contact movable parts, so they are used for assembling precision parts that do not like fine dust to adhere. It has the disadvantage that it cannot be used for pharmaceutical manufacturing, etc.

Furthermore, since shocks are applied to the conveyed object when starting and stopping, it is necessary to reduce the speed as much as possible when assembling precision parts. Therefore, there is also a drawback that the conveyance efficiency becomes poor.

eX) Purpose This invention aims to provide a method for controlling the movement of a conveyed object using a linear motor, which can perform slow lifting and slow stopping without generating fine dust or reducing conveyance efficiency. .

B) Structure A method for controlling the transfer of an object using a linear motor according to the present invention is a method for controlling the transfer of an object using a linear motor, in which the object is floated with compressed air while being driven by the linear motor, and the object is transported to a destination. A plurality of linear motors and a plurality of speed detection means are appropriately arranged between a starting point and an end point on the conveyance path, and based on the output of the speed detection means,
By controlling an inverter to supply an output of a predetermined frequency to the primary coil of the linear motor, the conveyed object is transported at a predetermined speed and stopped at a predetermined position. It is said that

(E) Embodiment FIG. 1 is a cross-sectional view showing one embodiment of the conveying device used in the present invention, FIG. 2 is a side view showing the above-mentioned embodiment, and FIGS. FIG. 3 is a plan view and a sectional view showing main parts of an example.

In the figure, reference numeral 1 denotes a conveyance conduit, and a conveyance table 2 is disposed at the center inside the conveyance conduit 1, and exhaust ducts 3 are provided on both sides of the lower part of the conveyance conduit 1. . The transport table 2 has two surfaces 2a12b having a positive slope symmetrically about the center line of the transport path, and horizontal surfaces 2 at both ends thereof.
It is made of a non-magnetic material such as aluminum or a Bakelite plate having a cross section of C, and nozzles 2d are symmetrically opened in the surface 2a12b. Further, this transport table 2 is kept airtight except for the nozzle 2d. Below the central part of the conveyance table 2, motors constituting the primary side of the linear motor are arranged at appropriate intervals in the conveyance direction.
A next-side iron core 4a and a coil 4b wound around this iron core 4a are arranged.

A high-pressure duct 5 through which compressed air flows below the primary iron core 4a
is provided.

A transport table 6 is placed above the transport table 2. The bottom portion 6a of the conveyance table 6 is made of a magnetic material such as a steel plate, and has a cross-sectional shape corresponding to the conveyance table 2.

7 is a compressor, and the compressed air produced by this compressor 7 is sent below the conveyance table 2 through the high-pressure duct 5, and at the same time is ejected above the conveyance table 2 through the nozzle 2d.

Reference numeral 8 denotes an exhaust fan, which exhausts air above the transfer table 2 through the exhaust duct 3. Reference numeral 9 denotes an object to be transported which is placed on a transport table.

Further, a plurality of speed detection means (not shown) are appropriately arranged between the starting point and the ending point on the conveyance path.

This speed detection means is composed of, for example, two reflective phototubes arranged at a predetermined distance apart, and these phototubes give a detection signal to a microcomputer to be described later when the carrier 6 passes. Then, this microcomputer calculates the speed of the carrier 6 when passing between the two phototubes.

FIG. 5 is a block diagram showing a control system of a device used in an embodiment of the present invention. In the figure, 10 is a microcomputer including a CPU 11, a ROM 12, a RAM 13, and an interface 14. The microcomputer 10 has a speed detector 15 as described above.
The speed of the conveyance table 6 is calculated and stored in the RAM 13. On the other hand, the speed of the conveyance platform 6 at the position of each speed detector 15 on the conveyance path is given in advance to the ROM 12. cpull compares the measured speed of the conveyance table 6 stored in the RAM 13 with the expected speed given to the ROM 12, and issues a command to control a predetermined linear motor according to the difference.

The control unit 16 controls the inverter 17 and the output switching mechanism 18 based on instructions from the microcomputer 10. As a result, inverter 1 was changed to an appropriate frequency.
7 is applied to the coil 4b of a predetermined linear motor via the output switching mechanism 18, the conveyance table 6 is accelerated or decelerated and set to a predetermined speed.

The operation of the above embodiment will be explained below.

FIG. 6 is an explanatory diagram of the operation of the embodiment. FIG. 6(A) is a diagram of changes in the frequency applied to the coils of each linear motor, FIG. The positions (in the same figure) indicate the positions of the coils of each linear motor.

First, compressed air produced by the compressor 7° is sent below the transfer table 2 via the high-pressure duct 5, and is ejected above the transfer table from the nozzle 2d. The ejected high-pressure air presses the bottom 6a of the carrier 6 upward, so that the carrier 6 floats up. Then, when a current for driving the linear motor is supplied to the coil 4b, the bottom 6a of the carrier 6 obtains a propulsive force by the magnetic flux of the primary side iron core 4a as a secondary side of the linear motor. For this reason, the transport platform 6
is slowly activated in the direction indicated by the arrow in FIG.

The air above the transport table 2 is then exhausted by the exhaust fan 8 via the exhaust duct 3.

As shown in Fig. 6, the near motor M! near the starting point at startup! An output of frequency f1 is supplied to.

When the carrier 6 starts slowly, the frequency is gradually increased to accelerate the carrier 6. Then, the conveyance table 6 is connected to a speed detector 15.
When the speed reaches H, the speed at that point is measured, and this value is compared with a value given in advance to the microcomputer 10, and the frequency of the inverter 17 is increased or decreased according to the difference. Therefore, although FIG. 6(a) shows the frequency change when the conveyance table 6 moves at a predetermined speed, the actual frequency changes somewhat depending on the speed error.

After the conveyance table 6 passes the speed detector 15a, the frequency applied to the linear motor M1 is lowered, and as a result, the conveyance table 6
becomes two constant speeds as shown in the same figure (b).

The linear motor M2 is used for speed adjustment in the constant speed section.

When the conveyance table 6 reaches the speed detector 15e, the speed at that point is compared with the planned speed, and the frequency is changed from f5 to f7 so that the linear motor M3 is excited in the opposite direction according to the speed difference. The transport platform 6 is then slowly stopped at the end point.

(f) Effects Since the method according to the present invention allows the transfer platform to be transferred without contacting the transfer table, no dust is generated during transfer. Therefore, the present invention is suitable for assembling precision parts where fine dust is averse and for manufacturing pharmaceuticals.

Further, according to the present invention, since slow starting and slow stopping can be performed without reducing the speed during transport, the transport efficiency does not deteriorate as in the conventional method.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a conveying device used in the present invention, FIG. 2 is a side view showing the embodiment, and FIGS. 3 and 4 are plan views showing essential parts of the embodiment. and cross-sectional view, fifth
The figure is a block diagram showing the control system of the device used in the embodiment of the present invention, and FIG. 6 is an explanatory diagram of the operation of the embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Conveyance pipe line, 2... Conveyance table, 2d... Nozzle, 3... Exhaust duct, 4a... Primary side iron core, 4
b...Coil, 5-...High pressure duct, 6...Transfer platform, 7...Compressor, 8...Exhaust fan, 9...
・Transferred object, 10...Microcomputer, 15...
-Speed detector, 16...control unit, 17...inverter. Patent Applicant Hitachi Kiden Kogyo Co., Ltd. Agent Patent Attorney Takaharu Ohnishi Figure 3 Figure 4 4a 4b Figure 5 0 16171e)

Claims (1)

[Claims] (1) In a method of controlling the transfer of a conveyed object using a near motor, in which the conveyed object is driven by a linear motor while being floated with compressed air, and the conveyed object is conveyed to the destination, multiple linear motors are connected between the starting point and the ending point on the conveying path. and a plurality of speed detection means are appropriately arranged, and an inverter is controlled to supply an output of a predetermined frequency to the primary coil of the linear motor based on the output of the speed detection means, 1. A method for controlling the transfer of a conveyed object using a linear motor, characterized in that the conveyed object is moved at a predetermined speed and stopped at a predetermined position.