JPH0125308B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the structure of a linear induction motor that can be driven by single-phase alternating current.

Linear induction motors have a simple and robust structure, so they have various advantages as a conveyance system. The driving force is normally generated by a traveling wave magnetic field generated by three-phase alternating current. However, when installing this type of linear induction motor in an office or a general household, it is more convenient to use single-phase AC. When creating a traveling wave magnetic field using single-phase alternating current, it has been known to use a shaded coil or a capacitor for phase advancement, but the former makes it difficult to control the direction of the traveling magnetic field, and the latter When obtaining large amounts of force, deterioration of the capacitor becomes a problem.

An object of the present invention is to realize a completely new single-phase linear induction motor that can form a traveling wave magnetic field without using a shaded coil, a capacitor, or the like.

The purpose of this is to form a return path for the magnetic flux generated from the first magnetic pole of the single-phase coil connected to the single-phase AC power supply, and to place the magnetic flux close to the first magnetic pole. a primary iron core having a second magnetic pole; a secondary conductor made of a non-magnetic good conductor that spans the first and second magnetic poles of the primary iron core and is arranged at a predetermined distance from each magnetic pole; an end of the secondary conductor that generates an energization instruction signal for energizing the single-phase coil with single-phase alternating current during a period when the end of the secondary conductor is located at a position facing the first magnetic pole; To provide a single-phase linear induction motor, comprising: a detection means; and one of the primary iron core or the secondary conductor is fixed and the other is movably supported. This is achieved by

The force generation principle of the linear induction motor (hereinafter referred to as LIM) according to the present invention will be shown below.

FIG. 1 shows the basic magnetic circuit of a single-phase LIM according to the present invention.

In the figure, 1 is the iron core, 2 is the first magnetic pole, 3, 4
is a second magnetic pole; 5 is a single-phase coil wound around the first magnetic pole 2; 6 is a yoke connected to a single-phase AC power source; be.

As shown in the figure, magnetic poles 2 to 4 are formed on the iron core 1, and a single-phase coil 5 connected to a single-phase AC power source is wound around the first magnetic pole 2. Therefore, single phase coil 5
The magnetic flux generated is generated in the direction shown by the arrow in the figure. Naturally, since it is an alternating magnetic field, the direction of the magnetic flux shown by the arrows in the figure also alternates.

At this time, the phase of the magnetic flux generated from the first magnetic pole 2 is 180 degrees ahead of that of the second magnetic poles 3 and 4. Further, the area of regions B and C forming the second magnetic poles 3 and 4 is set larger than the area A forming the first magnetic pole 2. This is to lower the magnetic flux density in regions B and C compared to the magnetic flux density in region A for reasons described later. At this time, in the initial state at empty G (the state in which a single-phase alternating current is applied to the single-phase coil 5 when the secondary conductor plate 8 is not present), in each region of regions A, B, and C. The generation distribution waveform of magnetic flux will be explained.

FIG. 11 is a waveform diagram of the initial magnetic flux density distribution in regions A to C, in which the figure is a waveform diagram in region A related to the first magnetic pole 2, and the same figure is a waveform diagram in regions B and C related to the second magnetic pole 3. In addition, each figure a is a diagram in which the waveform curve with the time axis perpendicular to the plane of the paper is displayed in perspective on the position axis X, and each figure b is a figure in each figure a.
FIG. 3 is a diagram of waveform curves when each waveform curve is observed from the position axis X direction.

In area A, as shown in Figure 11, each position
Waveforms A(X ₁ , _T ), A(X ₂ , T) at X ₁ , X 2
are both waveforms having the same phase, and the dotted line shows its envelope. Therefore, when each waveform curve in figure a is viewed from the position axis X direction, the two waveforms completely overlap and form one waveform A, as shown in figure b.
(T).

On the other hand, in regions B and C, as shown in FIG. ₁₁ , _the waveform B _{(X 1 ,}
T), B(X ₂ , T), and B(X ₃ , T) are waveforms having mutually different phases, and the dotted lines in the figure are the envelopes of the respective waveform curves. Therefore, these are placed on the time axis
When viewed from the direction, three waveform curves B(X ₁ , T), B(X ₂ , T), and B(X ₃ , T) are observed as shown in FIG.

The out-of-phase waveforms as described above are generated in regions B and C because of the alternating magnetic flux generated in the first magnetic pole 2 by applying a single-phase alternating current to the single-phase coil 5. This is because the eddy current induced in the iron core 1 causes magnetic resistance within the primary side iron core 1, and this magnetic resistance delays the phase of the magnetic flux. Therefore, the phase delay becomes larger outside regions B and C where the influence of the eddy current is greater. Next, we will discuss the force generated on the secondary conductor plate when a secondary conductor plate made of a non-magnetic material such as copper or aluminum is inserted into the air gap G of such a magnetic circuit configuration. This will be explained using FIG. In FIG. 3, the horizontal axis indicates the tip position of the secondary conductor plate 8, the vertical axis indicates the force acting on the secondary conductor plate 8 at that time, and the direction of arrow A indicates the position of the tip of the secondary conductor plate 8. 8 to the left in FIG. 2, and the direction of arrow A' is the force to move the secondary conductor to the right in FIG.

The length of the secondary conductor plate 8 in the traveling direction according to the present invention is set to be greater than or equal to the length indicated by symbol l in FIG. In the explanation of FIG. 2, a case will be explained in which the iron core 1 and the yoke 7 are fixed, and the secondary conductor plate 8 is movably supported.

First, when the tip 8-1 of the secondary conductor plate 8 is at the position a in FIG. 2, the force in the direction from area A to area B,
That is, as shown in FIG. 3, a force in the direction of arrow A' is generated.

This is because the magnetic flux generated from the single-phase coil 5 is alternating, so the phase of the magnetic flux in region B is delayed toward the inlet side due to the magnetic resistance including the first eddy current induced in the iron core 1. This is because a magnetic field traveling toward the entrance side is formed on the conductor plate 8.

As the tip 8-1 of the secondary conductor plate 8 approaches near b in FIG.
The eddy current density gradually increases, the phase of the magnetic flux at the tip 8-1 begins to lag, the traveling magnetic field on the secondary conductor plate 8 is canceled out, and its force becomes weaker.

That is, the phase of the magnetic flux in region B is a in FIG.
In the case of the position shown in FIG. Since the phase of the left portion of B is also delayed, the traveling magnetic field is canceled out.

Therefore, as shown in FIG. 3, the force acting on the secondary conductor plate 8 at position b becomes zero.

When the tip 8-1 reaches the position c in FIG. 2, it begins to be influenced by the magnetic flux in area A.

At this time, the phase of the magnetic flux at the tip 8-1 (the phase of the magnetic flux at the first magnetic pole 2) and the area B (the second magnetic pole 3)
The phase difference between the phase of the magnetic flux in the part of
Since the angle is 180° or more, a traveling wave is formed on the secondary conductor plate 8 in the direction of region B → region A, and from region B →
A force in the direction of region A, that is, a force in the direction of arrow A is generated as shown in FIG.

Furthermore, when the tip 8-1 advances to the position d in FIG. 2, another large eddy current different from the first eddy current is induced in the tip 8-1, and the magnetic flux of the tip 8-1 is The phase begins to lag, and the phase difference between the phase of the magnetic flux at the tip 8-1 and the phase in region B becomes 180 degrees again, and the force becomes zero, as shown in FIG.

Furthermore, when the tip 8-1 advances from d to e in FIG. 2, another large eddy current different from the first eddy current induced in the tip 8-1 causes the magnetic flux of the tip 8-1 to decrease. The phase is further delayed, and the phase difference in the portion in region B is 180° or less.

Therefore, a force is generated on the secondary conductor plate 8 in the direction from region A to region B. This force is maximum when the tip 8-1 is at position e in FIG. 2, as shown in FIG.

Furthermore, when the tip 8-1 passes through the position e in FIG. 2, this force decreases and becomes zero at the point f in FIG. 2, as shown in FIG.

This is the force (A
→C direction) and the force of the rear end 8-2 (A→B direction) are balanced.

When the tip of the secondary conductor plate 8 exceeds position f, the force at the rear end of the secondary conductor plate 8 becomes smaller than the force at the tip, and the force on the secondary conductor plate 8 moves toward the left in FIG. A force is generated towards.

The single-phase LIM according to the present invention skillfully utilizes the force in region X shown in FIG. 3 among the above-mentioned forces.

FIG. 4 shows an embodiment of a single-phase L/I/M according to the present invention.

In the figure, 1 and 1' are primary side iron cores, 2 are first magnetic poles formed at a predetermined interval on primary side iron cores 1 and 1', and 5-1, 5-1', 5-2, 5- 2', 5-
3, 5-3 are single-phase coils wound around the respective first magnetic poles, 5-1 and 5-1', 5-2 and 5-2', 5
-3 and 5-3' are respectively opposing first magnetic poles 2-1,
2-2 and 2-3, and are wire-connected to form a magnetic flux loop shown by the arrow in the figure. Also, 8 is a secondary conductor plate, 9-1, 9-2, 9
-3 is the tip sensor for the right direction, 10-1, 10-
Reference numerals 2 and 10-3 denote rear end sensors for the left direction, which are provided at positions corresponding to position d in FIG. 2 to detect the leading and trailing ends of the secondary conductor plate, respectively.
These sensors 9 and 10 are composed of, for example, reflective photodetectors.

Further, FIG. 5 shows a side view of the embodiment shown in FIG.
12 is a rail arranged on the primary iron cores 1 and 1';
13 is a carrier from which the secondary conductor plate 8 is suspended; 14 is a wheel for supporting the carrier 13 and moving it along the rail 12; For other numbers, the numbers in FIG. 4 are used as is.

The operation of this embodiment will be explained below using both figures.

Consider the case where the secondary conductor plate 8 is driven to the right in the figure.

First, hold the secondary conductor plate 8 so that its tip 8-1 is
Move it from the left side of the figure to the right side along the rail 12 and set it so that it is located between the right side front end sensor 9-1 and the left side rear end sensor 10-1. Therefore, the output of sensor 9-1 is "0", and the output of sensor 10-1 is "0".
The output of is inputted as a "1" signal to a drive circuit which will be described later. In this state, the drive circuit receives an enable signal from the operator or the host device and turns on the single-phase coil 5.
-1, 5-1' are configured to be able to supply single-phase alternating current. Furthermore, the same drive circuit is the sensor 9
The period when the output of sensor 10-1 is "0" and the output of sensor 10-1 is "1", that is, the tip of the secondary conductor plate 8-
The single-phase coil 5 is configured to be energized only when the single-phase coil 1 is located between the sensors 9-1 and 10-1.

Now, by the drive circuit, the single-phase coil 5-1, 5-
1', magnetic flux is generated from each single-phase coil as shown by the arrow in the figure, and as a result, the secondary conductor plate 8 is forced to the right based on the principle explained in Figure 2. and moves to the right on the rail 12 while being guided by the rail 12. Then, the period during which the tip 8-1 of the secondary side conductor plate is located between the opposing first magnetic poles 2-2 is detected by the sensors 9-2 and 10-2, and the single-phase coil 5 connected to the same drive circuit is detected. -2,5-
2' is supplied with single-phase alternating current. As a result, the secondary conductor plate 8 is further accelerated and moved to the right.
Thereafter, the secondary conductor plate 8 can be transported along the rail 12 in the same manner. Also, secondary side conductor plate 8
When transferring to the left, both sensors 9 and 10 detect the rear end 8-2 of the secondary conductor plate in exactly the same way, and the single-phase coil is energized while the rear end is located between both sensors. Just do it.

FIG. 6 shows an example of a drive circuit connected to the embodiments shown in FIGS. 4 and 5. FIG.

In the figure, 15 and 16 are AND gates, 1
7 is an OR gate, 18 is an inverter, 19 is a set-reset type flip-flop, 20 is a solid state relay, and 21 is a single-phase AC power supply, and the other numbers refer to those in FIG.

The illustrated drive circuit includes the coil 5 shown in FIG.
1 and 5-1'. The single-phase AC power supply 21 is connected to the coil 5 through the relay 20.
Although not shown, other coils 5-2, 5-2', 5-3, and 5-3' are also connected in parallel to the power supply 21.

Now, in FIG. 4, the sensors 9-1, 10-1 are first moved by the secondary conductor plate 8 which is moved from the left side.
As a result of turning on, flip-flop 19 is set via gate 15. Furthermore, the secondary conductor plate 8
When it moves to the position shown in FIG. 4, the sensor 9-1 is turned off, the output of the gate 15 is "0", and the output of the inverter 18 is therefore "1". At this time, when the enable signal is input, the gate 16 opens and the relay 20 closes. Therefore, single-phase alternating current is supplied to the single-phase coils 5-1, 5-1'. By energizing the single-phase coil, the secondary conductor plate 8
is rapidly accelerated to the right. On the other hand, secondary side conductor plate 8
Due to the movement of , both sensors 9-1 and 10-1 are turned off, and a reset pulse is input from gate 17 to flip-flop 19, gate 16 is closed, and energization to single-phase coils 5-1 and 5-1' is stopped. .
Note that the start 1 terminal in the figure is a terminal for enabling current to be applied to the single-phase coil regardless of the output of the sensor.

The above-described drive circuit is connected to each single-phase coil shown in FIG. 4, respectively.

Here, the length of the secondary conductor plate 8 in the traveling direction is set to be larger than the distance L between the sensors 10-1 and 9-2 arranged at the position corresponding to position d in FIG. By setting the distance between the outer edges of the magnetic poles 2-1 and 2-2 smaller than the distance M, the secondary conductor plate 8
It is also possible to accurately position the stop.

That is, in the above description, a case has been described in which the single-phase coil is used only for transferring the secondary conductor plate, but the single-phase coil can also be used to accurately stop and position the secondary conductor plate 8 without contact.

In this case, the drive circuit shown in FIG. 7 is applied to the drive circuit connected to each single-phase coil 5.

In the figure, 22 to 26 are AND gates,
27, 28 are OR gates, 29 is an inverter, 3
0 and 31 are set/reset type flip-flops, and 32 is a solid state relay connected in series with the coils 5-2 and 5-2'.

The outputs of the sensors 10-1 and 9-2 are input to the gate 22, and when both outputs are "1", that is, when the secondary conductor plate 8 is in the position shown in FIG. A signal for supplying alternating current to both single-phase coils 5-1, 5-1', 5-2, and 5-2' located at the front and rear ends of the coil is output. Therefore, the gate 22 is opened and the flip-flop 30 is set, and the negative pulse of the enable signal is activated.
When ENABLE GO is input, gate 24,
25 opens. The respective outputs of the gates 24 and 25 turn on the relays 20 and 32, respectively, so that alternating current is simultaneously supplied to the single-phase coils 5-1, 5-1', 5-2, and 5-2'.

By energizing both single-phase coils, the secondary conductor plate 8 between the two single-phase coils generates a force toward the center of the plate at both ends, and eventually the secondary conductor plate 8 is held between the two single-phase coils. Ru. During the period when the secondary conductor plate is stationary, alternating current is continuously supplied to both single-phase coils. When moving the secondary conductor plate 8 again, by stopping the energization to either one of the single-phase coils located at both ends of the secondary conductor plate, the direction of the de-energized single-phase coil is moved. The secondary conductor plate can be restarted. That is, when moving the secondary conductor plate 8 to the left in FIG.
A signal is given to the start terminal START1 in Fig. 7 to turn off the relay 20 and the single-phase coils 5-1, 5-
1' is stopped. In addition, when moving to the right, a signal is given to the start terminal START2 to turn off the relay 32, and the single-phase coils 5-2, 5-
2' may be stopped.

In addition, gates 23, 26, 28, inverter 2
9. The circuit consisting of the flip-flop 31 is similar to the drive circuit for driving each single-phase coil shown in FIG. 6, and its operation is exactly the same as that in FIG. 4.

FIG. 8 is a principle explanatory diagram showing another embodiment of the single-phase L/I/M according to the present invention. In this embodiment, the secondary conductor plate is fixed to the base and the primary iron core is movable, and the driving principle is exactly the same as that shown in Figs. 2 and 3, so the explanation is omitted here. do.

In the figure, 41, 41' are movably supported primary side cores, 42 is a first magnetic pole formed approximately at the center of the primary side iron cores 41, 41', and 43, 44 are primary side iron cores 41, 41'. The second
The magnetic poles 45 and 45' are single-phase coils wound around the first magnetic pole 42, 48 is a secondary conductor plate fixed along the rail at a predetermined interval, and 49 and 50 are secondary conductor plates. This is a sensor for position detection.

A specific configuration example of another embodiment shown in FIG. 8 is shown in FIG.
and FIG. 10.

In the figure, 51 is a base, 52 is a rail, 53 is a carrier, 54 is a wheel provided on the outside of the primary side cores 41, 41', 55 is a sliding brush connected to the single-phase coil 45, 45' terminal, 56 is a current supply rail arranged on the base 51 and connected to a single-phase AC power source.

As can be seen from FIG. 9, in this embodiment, the rail 52
Secondary conductor plates 48 are arranged at predetermined intervals, while primary cores 41, 41' are movably supported on rails 52 via wheels 54. The primary side iron cores 41, 41' have single-phase coils 45, 45', 46, 4 facing each other at both ends thereof.
6', single phase coils 45, 45' and 46,
The distance between 46' is set to be approximately equal to the length of the secondary conductor plate 48.

The operating principle is exactly the same as that shown in Fig. 8, and the fourth Based on the principle shown in the figure, a transport body consisting of a primary iron core and a carrier can be transported in a predetermined direction. The supply of alternating current to each single-phase coil takes place via a power supply rail and brushes in sliding contact therewith. In this embodiment, when the carrier is stopped, alternating current may be simultaneously supplied to the single-phase coils 45, 45', 46, and 46' at both ends of the primary core, as in the previous embodiment.

As described above, according to the present invention, it is possible to realize a linear induction motor with a simple configuration that can obtain a traveling wave magnetic field using a single-phase AC power source.

[Brief explanation of drawings]

FIG. 1 shows the basic magnetic circuit of a single-phase L-I-M according to the present invention, and FIGS. 2 and 3 show diagrams illustrating the operating principle of the single-phase L-I-M according to the present invention. FIGS. 4 and 5 show a configuration diagram of an embodiment of the present invention, and FIG. 6 shows an example of its driving circuit. FIG. 7 shows another embodiment of the drive circuit applied to the present invention. Figures 8 and 9
10 are diagrams for explaining other embodiments of the present invention, and FIG. 11 is an initial magnetic flux density distribution waveform diagram in regions A to C. is a waveform chart in regions B and C related to the second magnetic pole. In the figure, 1 is the primary iron core, 2 is the first magnetic pole,
3 and 4 are second magnetic poles, 5 is a single-phase coil, 8 is a secondary conductor plate, 9 and 10 are sensors, 11 is a base, 12 is a rail, 13 is a carrier, and 14 is a wheel.

Claims (1)

[Scope of Claims] 1. A first magnetic pole around which a single-phase coil connected to a single-phase AC power supply is wound, and a return path for magnetic flux generated from the first magnetic pole, which is arranged close to the first magnetic pole. a primary iron core having a second magnetic pole; a secondary conductor made of a non-magnetic good conductor that spans the first and second magnetic poles of the primary iron core and is arranged at a predetermined distance from each magnetic pole; and; a secondary conductor end that generates an energization instruction signal for energizing the single-phase coil with single-phase alternating current during a period when the end of the secondary conductor is located at a position facing the first magnetic pole; 1. A single-phase linear induction motor, characterized in that one of the primary iron core or the secondary conductor is fixed and the other is movably supported. 2. The single-phase linear induction motor according to claim 1, wherein the primary iron core is fixed and the secondary conductor is movable. 3. Claims characterized in that the first magnetic poles and the second magnetic poles constituting the primary iron core are arranged alternately, and the interval between the first magnetic poles is set to be substantially the same as the length of the secondary conductor. The single-phase linear induction motor according to item 2. 4. The single-phase linear induction motor according to claim 1, wherein the secondary conductor is fixed and the primary iron core is movable. 5. Claim 4, characterized in that first magnetic poles are arranged on both sides of the second magnetic pole of the primary iron core, and the interval between the first magnetic poles is set to be substantially the same as the length of the secondary conductor. Single-phase linear induction motor as described in . 6. The single-phase linear induction motor according to claim 5, wherein the secondary conductors are arranged at predetermined intervals along the moving direction of the primary iron core. 7. Claim 1, characterized in that the single-phase coil is wired so that the magnetic flux forms a loop.
A single-phase linear induction motor according to items 5 to 5.