JPS6314582B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to linear induction motors (hereinafter abbreviated as L, I, and M), and more particularly to a stop positioning device for L, I, and M.

Since L, I, and M have simple and robust structures, small-sized ones are being used in various automatic control devices, physical distribution devices, or transportation systems for peripheral terminal devices connected to computers.

By the way, conventionally, this type of stop positioning of L, I, and M is performed by the friction force caused by mechanical contact between the movable part and the guide rail, so: 1. A complicated braking mechanism with friction plates is required. It is.

2. The stopping position of the movable part changes due to wear of the friction plate.

3 Frictional heat has an adverse effect on the mechanism.

4. Friction produces bad odors, smoke, and noise.

Problems such as these occur, and it is particularly inconvenient to apply it to office equipment.

SUMMARY OF THE INVENTION The object of the present invention has been made in view of the above-mentioned drawbacks, and it is an object of the present invention to realize a stop positioning device with a simple construction.

Another object of the present invention is to realize a stop positioning device that can reliably stop a movable part at a predetermined stop position in a non-contact manner.

The present invention will be explained below using the drawings.

FIG. 1 is a diagram of the operating principle (a diagram of the principle of force generation by a single-phase alternating current magnetic field) of the stop positioning device for L, I, and M according to the present invention. In the figure, 1 and 1 are a pair of fixed primary iron cores, and 2 is a secondary conductor of a predetermined length made of a good conductor such as Al or Cu.

A groove 3 is provided in the primary iron core 1, and magnetic pole parts 4 and 5 are formed on both sides of the groove 3. Magnetic pole part 5
The magnetic pole area is set to be larger by an appropriate amount than the magnetic pole area of the magnetic pole part 4, and a single-phase coil 6 is wound around each magnetic pole part 4. The graph shown at the bottom of the figure is a magnetic flux density distribution diagram when a DC voltage is applied to the single-phase coil when no secondary conductor is present.

The secondary conductor 2 is movable between the primary cores 1, 1 in the directions of arrows A and A'.

Now, when single-phase alternating current is applied to the single-phase coil 6,
A magnetic flux loop F as shown by the dotted line in the figure is constructed, but since it is an alternating magnetic field, the direction of the magnetic flux also alternates.
At this time, the phase of the magnetic flux in the air gap 7 between the magnetic pole parts 4, 4 is greater than the phase of the magnetic flux in the air gap 8 between the magnetic pole parts 5, 5.
This means that the magnetic flux density in the air gap 8 is smaller than the magnetic flux density in the air gap 7 (because the magnetic pole area of the magnetic pole part 5 is wider than the magnetic pole area of the magnetic pole part 4).

When the secondary conductor 2 is inserted into the gap of such a magnetic circuit configuration, the following force is generated in the secondary conductor 2.

That is, when the tip of the secondary conductor 2 is at position a, a force in the direction of arrow A' is generated. This is because the phase of the magnetic flux in the air gap 8 is delayed toward the entrance side due to the eddy current induced inside the secondary conductor 2, so a traveling magnetic field is formed on the secondary conductor 2 facing the entrance side. It is.

Next, as the tip of the secondary conductor 2 approaches position b, the density of the eddy current I _E8 induced at the tip gradually increases as shown in FIG. 2, and the phase of the magnetic flux at the tip begins to lag. The traveling magnetic field on the secondary conductor 2 is canceled out, and the force in the direction of arrow A' becomes weaker.

Next, when the tip of the secondary conductor 2 reaches position c, it begins to be influenced by the magnetic flux in the air gap 7, and the magnetic flux at the tip of the secondary conductor 2 and the magnetic flux in the air gap 8 are different. Since the phase difference is 180 degrees or more, a traveling wave in the direction of arrow A is formed on the secondary conductor 2,
A force in the same direction is generated.

Next, when the tip of the secondary conductor 2 advances to position d,
As shown in Figure 3, there is a large eddy current at the tip.
I _E7 is induced and the phase of the magnetic flux at the tip begins to lag, and the phase difference between the magnetic flux at the tip and the magnetic flux at the portion S in the air gap 8 becomes 180 degrees again, and the secondary conductor 2
No traveling magnetic field is formed above, and the force becomes zero.

Next, when the tip of the secondary conductor 2 moves from position d to position e, the phase of the magnetic flux at the tip further lags,
The phase difference between the magnetic flux at the tip and the magnetic flux at the portion within the air gap 8 is 180 degrees or less. Therefore, a force in the direction of arrow A' is generated on the secondary conductor 2. This power is
It is maximum when the tip of the secondary conductor 2 is at position e.

When the tip of the secondary conductor 2 passes the position e, the force generated in the secondary conductor 2 decreases and becomes zero at the position f. This is because the forces between the tip and the rear of the secondary conductor 2 are balanced.

The maximum value (absolute value) of the force acting on the secondary conductor 2 due to the generation of a traveling magnetic field for each section in the same direction.
When F is expressed with a subscript indicating the tip position of the secondary conductor 2 in Fig. 1, there is a relationship between F _ab , F _c , and F _de as F _ab > F _c > F _de , Also, at position d, it is in a balanced state.

Therefore, the structures of the primary iron core 1 and the single-phase coil 6 shown in FIG.
If the secondary conductor 2 is prepared with a notch (one piece) corresponding to the distance between point d and its symmetry point d' in FIG. A force acts to draw each of the tips of the secondary conductor 2 forming the notch to the point d and its symmetrical point d' to bring them into an equilibrium state.

In addition, the structure is symmetrical with respect to the virtual center line of the magnetic pole part 5, so that the magnetic pole part 5 is shared, the magnetic pole part 4 and the single-phase coil 6 are symmetrically arranged on the left and right, and two notches as described above are provided. By preparing corresponding to the magnetic pole parts 4, in the same manner as above, when the two notches are located near the two magnetic pole parts 4,
It is possible to create a force that draws the tips of the two notches to each point d and its symmetry point d' to bring them into a balanced state.

The stop positioning device according to the present invention utilizes the above-mentioned operating principle, and the present invention is also characterized in that the secondary conductor is fixed along the conveyor rail and the primary iron core is transferred along the conveyor rail. This relates to a stop positioning device for a linear induction motor.

An embodiment according to the present invention is shown in FIGS. 4 and 5. FIG. 4 is a side sectional view of the stop positioning device according to the present invention, and FIG. 5 is a top sectional view thereof.

In both figures, 11 is a primary iron core that is a movable part, 12 is a traveling magnetic field generation coil wound around the primary iron core 11, 13 is a single-phase coil for stop positioning, and 14 is a power supply rail and a sliding brush. 15 is a wheel that guides and supports the primary iron core 11, 16 is a conveyor rail provided corresponding to the wheel 15, and 17 is a non-magnetic good conductor provided opposite to the primary iron core 11. The secondary conductor extends along the transport rail 16. 1
Reference numeral 8 denotes a photodetector installed in a station portion where the primary side iron core 11 is to be stopped and positioned, and 19 denotes a reflection plate arranged at a position corresponding to the photodetector 18 of the primary side iron core 11.

As is clear from FIG. 5, a traveling magnetic field generating coil 12 is wound around the primary iron core 11, and a single-phase coil 13 for stop positioning is also wound around a part of it.

Further, a notch 20 is formed in the secondary conductor 17 in the station portion.

The operation of the L, I, M stop positioning device according to the present invention will be explained below.

Assuming that the primary core 11 is guided by the transport rail 16 and enters the station section from the left direction in the figure, first the left photodetector 18 installed in the station section is connected to the reflector plate attached to the primary core 11. 19' detects. As a result, the photodetector 18
The output signal is input to a drive control circuit (not shown), and a current is applied to the traveling magnetic field generating coil 12 in a direction that generates a braking force. Of course, the energization time at this time is set in advance to such an extent that the traveling direction of the primary iron core does not change. The primary core 11 gradually enters the station part while being subjected to braking force, and is wound around the primary core 11 when the photodetector 18' detects the reflection plate 19' on the right side of the primary core 11. Single-phase coil 13 for central stop positioning
A single-phase alternating current is supplied from a drive control circuit (not shown). The magnetic flux 21 generated from the single-phase coil 13 for stop positioning is indicated by a broken line in the figure. As a result, the primary iron core 11 is accurately stopped and positioned at a position where the single-phase coil 13 for stop positioning is opposed to the notch 20 as shown in the drawings, based on the principle explained in FIGS. 1 to 3.

The above operation is exactly the same when the primary iron core 11 enters the station portion from the right side in the figure.
After the primary iron core 11 has stopped at the station, the single-phase AC current to the single-phase coil 13 for stop positioning may be stopped; however, if the conveyor rail is installed at an incline, It is desirable to continue to do so.

Primary iron core 11 stopped at the station
In order to transfer the magnetic field again, first stop the energization to the single-phase coil 13 for stop positioning, and then switch the traveling magnetic field generating coil 12 according to the desired direction of movement.
By starting energization, it is possible to move the object in a predetermined direction.

The traveling magnetic field generating coil 12 wound around the primary iron core 11 and the single-phase coil 13 for stop positioning are energized by the power supply rail laid on the base and the movable side, as shown in FIG. This is performed by a power feeding section 14 consisting of a sliding brush attached to the primary side iron core 11 side.

FIG. 6 shows another embodiment of the L, I, M stop positioning device according to the present invention.

It should be noted that all the numbers in the figure are the same as those in FIG. 5.

As is clear from the figure, in this embodiment, the stop positioning coils 13 and 13' are arranged at two locations in the front and back along the direction of movement of the primary core 11, and the secondary conductor 17 is cut at two locations in the station section. Notches 20, 20' are formed.

Both stop positioning coils 13, 13' wound around the primary iron core 11 are connected by wiring so as to form a magnetic flux loop 21' as shown in the figure when energized with single-phase alternating current at the time of stop. Also, both coils 13,1
3' are respectively positioned so that the relative positions of the teeth of the primary core 11 to be wound and the notches 20, 20' provided in the secondary conductor 17 are as shown in FIG. 1d. It is located.

Since the operation is exactly the same as that of the embodiment shown in FIG. 5, the explanation thereof will be omitted.

According to this embodiment, the stop positioning of the primary iron core can be performed more accurately and powerfully than in the embodiment shown in FIG. FIG. 7 shows L according to the present invention,
Still another embodiment of the stop positioning device for I and M is shown. It should be noted that all the numbers in the figures refer to the numbers assigned to the embodiment of FIG. 5.

This embodiment is a modification of the embodiment shown in FIG. 5, and differs from the embodiment shown in FIG. Part of the coil 12' of the generating coil 12 is used as a single-phase coil for stop positioning.

This embodiment shows a case in which a three-phase AC power source is connected to a traveling magnetic field generating coil, as in the previous embodiments, but this embodiment is different from the previous embodiments in that The traveling magnetic field generating coils 12 that are rotated are connected in parallel to each phase power source.

That is, in this embodiment, a single-phase alternating current is applied to a part of the coil 12' of the traveling magnetic field generating coil 12 at a predetermined timing, and the stop position is determined at the notch 20 of the secondary conductor 17. Therefore, the coils connected to each phase power source are necessarily connected in parallel to each phase power source.

Connection of the three-phase AC power source to the traveling magnetic field generating coil 12 including the stop positioning coil 12' and switching of the connection of the single-phase AC power source only to the stop positioning coil 12' are performed by a drive control circuit (not shown). It is done. Although the timing of this switching is not shown, it goes without saying that it is performed based on the output signals from both detectors and both reflectors, as in the previous embodiment.

As explained above, according to the present invention, it is possible to realize a non-contact type stop positioning device for L, I, and M that has a simple configuration and is inexpensive.

[Brief explanation of the drawing]

FIG. 1 is an operational principle diagram for explaining the stop positioning device of the present invention, FIGS. 2 and 3 are diagrams for further explaining FIG. 1, and FIGS. 4 and 5 are diagrams for explaining the stop positioning device of the invention. 6 shows another embodiment of the stop positioning device according to the present invention, and FIG. 7 shows a further embodiment of the stop positioning device according to the present invention. This is another example. In the figure, 11 is the primary iron core, 12 is a traveling magnetic field generation coil, 13 is a single-phase coil for stop positioning,
17 is a secondary conductor, 18 is a photodetector, 19 is a reflection plate, and 20 is a notch.

Claims (1)

[Scope of Claims] 1. A primary iron core that is guided and supported by a conveyance rail and around which a traveling magnetic field generating coil is wound, and a secondary conductor made of a good conductor that extends along the conveyance rail. By energizing the traveling magnetic field generating coil, the primary iron core is transported along the conveyor rail, and when the arrival of the primary iron core is detected at the station where the primary iron core is to be stopped, the traveling magnetic field is In a stop positioning device for a linear induction motor that is energized and braked so that the direction of movement is reversed, at least one single-phase coil for stop positioning is disposed on the primary iron core, and the primary side A notch is formed in the secondary conductor of the station section where the iron core is to be stopped, and the single-phase coil for stop positioning is connected to the single-phase coil for stopping positioning during the period when the single-phase coil for stopping positioning corresponds to the notch in the secondary conductor. A stop positioning device for a linear induction motor, characterized in that a single-phase alternating current is supplied to a coil to stop the primary iron core at a station. 2 A primary iron core guided and supported by a conveyance rail and around which a traveling magnetic field generating coil is wound, and a secondary conductor made of a good conductor extending along the conveying rail, In a stop positioning device for a linear induction motor that transports the primary iron core along a conveyor rail by energizing, each traveling magnetic field generating coil wound around the primary iron core is connected in parallel to a power source. It is composed of an assembly of a plurality of coils, and a notch is formed in the secondary conductor plate of the station part where the primary iron core is to be stopped and positioned, so that a part of the traveling magnetic field generating coil is connected to the secondary conductor. A stop positioning device for a linear induction motor, characterized in that a single-phase alternating current is supplied only to the coil during a period corresponding to the notch to stop the primary iron core at a station.