JPS633553B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stop and hold device suitable for holding a movable body (for example, a secondary conductor), such as a linear induction motor (hereinafter abbreviated as L, I, M), at a stop. It is something.

Conventionally, L, I, and M have simple structures and are strong, so small ones are being used in various automatic control devices, logistics 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. A mechanism is necessary.

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

(3) Frictional heat adversely affects the mechanism.

(4) Friction produces foul odors, smoke, and noise.

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

The present invention was made in view of the drawbacks of lyricism, and its purpose is to be able to stop and hold a movable member without contact, to have a simple structure, and to always stably hold the movable member in a predetermined position. An object of the present invention is to realize an induction type stop and hold device that can be stopped and held in a certain position.

The purpose of this is to create a main magnetic pole around which a single-phase AC magnetic field generating coil is wound, a holding magnetic pole magnetically coupled to the main magnetic pole, a magnetic body consisting of a magnetic body, and a conductor that moves relative to the magnetic body. a first eddy current induced in the conductive plate by a magnetic field generated by the main magnetic pole at a position where the conductive plate faces the auxiliary magnetic pole and the end thereof faces the main magnetic pole. The relative movement between the magnetic body and the conductor plate is stopped and maintained by the generated force and the force generated by the second eddy current induced in the conductor plate by the magnetic field generated by the auxiliary magnetic pole. This is achieved by providing an inductive stop and hold device characterized by:

Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a diagram (explanatory diagram of the principle of force generation by a single-phase alternating current magnetic field) for explaining the operating principle of the induction type stop and hold device according to the present invention.

In the figure, 1 and 1 are a pair of fixed primary cores,
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 a main magnetic pole part 4 and an auxiliary magnetic pole part 5 magnetically coupled to the main magnetic pole part 4 are formed on both sides of the groove 3. The magnetic pole area of the auxiliary magnetic pole part 5 is set to be wider than the magnetic pole area of the main magnetic pole part 4 by an appropriate amount.
A single-phase coil 6 is wound around.

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 main magnetic pole parts 4, 4 is 180 degrees ahead of the phase of the magnetic flux in the air gap 8 between the auxiliary magnetic pole parts 5, 5, and
The magnetic flux density of is smaller than the magnetic flux density of the air gap 7 (because the magnetic pole area of the auxiliary magnetic pole part 5 is wider than the magnetic pole area of the main 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 lags behind the entrance side due to the eddy current induced inside the primary iron cores 1, 1, so a traveling magnetic field is formed on the secondary conductor 2 facing the entrance side. It is.

Therefore, due to this force in the direction of arrow A', the secondary conductor 2 receives a braking force, and its approach speed is reduced.

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 becomes influenced by the magnetic flux of the air gap 7, and the position of the magnetic flux at the tip of the secondary conductor 2 and the magnetic flux in the part where the air gap 8 is 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, and 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 force is maximum when the tip of the secondary conductor 2 is at position e.

FIG. 7 shows the position of the tip of the secondary conductor 2 and the state of force applied to the secondary conductor 2 at this time.

In FIG. 7, the direction of movement of the secondary conductor 2 is
This is the direction from the left side to the right side of the figure.

In addition, the A' direction of the vertical axis indicates the force that moves the secondary conductor 2 to the left (the direction that pushes back the secondary conductor), and the A direction indicates the force that moves the secondary conductor 2 to the right (the direction that pushes the secondary conductor back). The horizontal axis indicates the position, and the positions indicated by symbols a to e correspond to the positions indicated by symbols a to e in FIG. 1. .

As is clear from the figure, in the part of ,
The force acting on the secondary conductor 2 is approximately zero.

However, in the part where the secondary conductor 2 advances from the left side, the advancing force is large, and if it deviates even slightly to the right from the zero part, it will jump out to the right from the part.

Also, if the advancing force is small and the vehicle stops on the left side, it will jump out to the left from the area. Further, even if the movable body were to stop within the part, if an external force is applied to the movable body, it would be in an extremely unstable state, as it would jump out of the same part.

On the other hand, when the secondary conductor 2 advances from the left side, the left side part receives a force that tries to advance to the part, and the right part similarly tries to return to the other part. A force acts on it, and it always stops stably at position d.Of course, even when an external force is applied, a centripetal force acts on it to try to return to position d.

Furthermore, as is clear from Fig. 7, when the secondary conductor 2 approaches from the left side of the figure, near position a, depending on the approach speed of the secondary conductor 2,
Since a force is generated that tries to push back the secondary conductor 2, the secondary conductor 2 is sufficiently decelerated by this force.

Therefore, when the advancing speed of the secondary conductor 2 is not so fast, it is possible to determine the stop position without requiring a braking operation using a traveling magnetic field generating coil or the like.

Although it is slightly accelerated at position c, there is no problem because a force pushing back the secondary conductor 2 acts on the right side of position d.

That is, the present invention stops and holds the secondary conductor 2 by using the centripetal force that tries to return to the position d obtained by the two forces generated by the two eddy currents induced in the secondary conductor 2. .

A fourth embodiment of the induction type stop and hold device according to the present invention, which utilizes the operating principle as explained above, is described below.
This will be explained using FIG.

Incidentally, FIG. 4 is a side view showing an embodiment of L, I, and M using the induction type stop and hold device according to the present invention, and FIG. 5 is a top view thereof.

In each figure, 9 is a traveling magnetic field generating coil wound around each magnetic pole of the primary iron cores 1, 1 arranged on both sides of the secondary conductor 2, and 10, 10' are the traveling magnetic field generating coils of the secondary conductor 2.
A photodetector consisting of a light emitter and a light receiver for detecting the position of the light emitter, 11 is a guide rail provided continuously on the upper part of the primary core as shown in FIG.
2 is a wheel that can rotate freely on the guide rail 11, and 13 is a carrier connected to the secondary conductor 2.

In the induction type stop and hold device according to this embodiment, the length of the secondary conductor is set shorter than the length of the primary cores 1, 1, as can be seen with reference to FIG.

Further, a pair of single-phase coils 6, 6' for stop positioning disposed on the primary iron cores 1, 1 are provided at an interval substantially equal to the length of the secondary conductor 2.

In other words, the arrangement of the single-phase coils 6 and 6' is as follows:
As explained using the operating principle diagram of FIG. 1 and FIG. They are set at positions where both the forces in the A and A' directions are zero. Each single-phase coil 6, 6' is wired so as to generate a magnetic flux loop as shown by the broken line F' in FIG.

That is, the secondary conductor 2 is arranged so that the force described in FIG. 7 acts on the front end and the rear end of the secondary conductor 2, respectively.

As a result, at the tip of the secondary conductor 2,
A force of a magnitude corresponding to the left side of position d in FIG. 7 acts in the right direction (return direction).

Also, on the rear end side, a force in the direction exactly opposite to the tip of the secondary conductor 2 acts, and the force in the pulling direction on the left side of position d in FIG. 7 acts on the secondary conductor 2. Since it acts as a force in the pushing back direction, the secondary conductor 2 can be stably held in a stationary state by the resultant force of both.

Further, the photodetectors 10 and 10' each have a first
The photodetectors 10 and 10' are arranged at a position indicated by position d in the figure, or at a predetermined interval that is equal to or shorter than the secondary conductor 2, and each photodetector 10, 10' is connected to a drive circuit shown in FIG. 6, which will be described later. Connected.

The operation of this embodiment will be explained step by step below.

In FIG. 5, a case will be described in which the secondary conductor 2 enters from the entrance side A.

First, when the tip of the secondary conductor 2 crosses the photodetector 10', the traveling magnetic field generating coil 9 is energized in the direction in which a brake is applied to the secondary conductor 2. The current application time at this time is adjusted in advance in the traveling magnetic field generating coil drive circuit to such an extent that the traveling direction of the secondary conductor 2 does not change.

Next, when the secondary conductor 2 advances and the photodetector 10 detects the tip of the secondary conductor 2, single-phase alternating current is simultaneously applied to the single-phase coils 6 and 6' on both the inlet and outlet sides. Alternatively, first apply single-phase alternating current to the single-phase coil 6 on the outlet side, and then delay it for a predetermined period of time (a time long enough to apply the brake to the secondary conductor 2 so that the traveling direction does not change) and then apply the single-phase alternating current to the single-phase coil 6 on the inlet side. Single-phase AC is applied to 6'.

As a result, the secondary conductor 2 is positioned to stop between the single-phase coils 6 and 6' at both ends, as shown in the figure.

In this state, both ends of the secondary conductor 2 are stopped and held at the position shown by d in FIG. 1, no force is applied to the secondary conductor 2, and it remains stably stationary.

When starting the secondary conductor 2 again, the single-phase coils 6 and 6' are de-energized, and the traveling magnetic field generating coil 9 is energized, so that the secondary conductor 2 can be started in either the selected left or right direction. can.

FIG. 6 is a diagram showing an example of a drive circuit applied to the above embodiment.

In the figure, 14 is an OR circuit, 15, 21, 2
2 is an AND circuit, 16, 17, and 18 are NAND circuits, and the NAND circuits 17 and 18 form a latch circuit 19.
It consists of Further, 20 is a pulse generator, which generates a braking period designation pulse P for applying braking to the secondary conductor of the traveling magnetic field generating coil 9 for a certain predetermined time as described above.

27 is a three-phase AC power supply, 23 and 24 are relays inserted into two output terminals from the three-phase AC power supply 27, and 25 is two output terminals of the three-phase AC power supply 27 and single-phase coils 6 and 6'. This is a relay inserted in a series closed circuit. Further, the numbers in FIG. 5 are used as they are for the photodetector, single-phase coil, and traveling magnetic field generating coil.

The illustrated embodiment shows an example of a drive circuit applied to a conveyance system in which a plurality of low-ground positioning devices according to the present invention are arranged on a relatively long-distance conveyance rail. In addition, the secondary conductor 2 that constitutes the movable part is
A system that allows access from any direction to the stop and hold device as shown in FIG. 5 along the conveyor rail;
In other words, it assumes movement in both directions.

Therefore, the present drive circuit is also constructed assuming bidirectional entry into the stop and hold device of the secondary side conductor.

Therefore, there is no problem even if the photodetectors 10 and 10' in the figure are arranged in the opposite direction.

When one of the photodetectors 10 and 10' detects the entry of the secondary conductor 2 into the stop and hold device,
The detection signal is first input to the pulse generation circuit 20, and a braking period designation pulse p having a predetermined pulse width t is sent via the gate 21 to activate the relays 23 and 24. By operating the relays 23 and 24, the traveling magnetic field generating coil 9 generates a negative phase magnetic field in the direction of braking the secondary conductor 2 for a predetermined period of time to brake the secondary conductor 2, and then the photodetector 10, 10'
When both detect the entry of the secondary conductor 2, the detection signal is input to the latch circuit, activates the relay 25, and starts energizing both single-phase coils 6 and 6'.
The secondary conductor is stopped and held.

Note that the terminal 26 in the figure is an enable terminal, and the output of the latch circuit 19 is prohibited by the gate 22 so that the stop holding device through which the secondary side conductor 2 is to be passed is not activated, and the relay 25 is not activated. It is for.

Additionally, this drive circuit simultaneously drives a pair of single-phase coils using the output from the photodetector.
It is also possible to adopt a drive circuit that first drives the single-phase coil on the exit side of the stop positioning device and then drives the single-phase coil on the entrance side.

In this case, this can be easily realized by incorporating a delay circuit or a sequential circuit into the present drive circuit.

As described above, according to the present invention, it is possible to realize an induction type stop and hold device that has a simple configuration and can reliably stop a movable part without contact.

[Brief explanation of the drawing]

Fig. 1 is an operational principle diagram for explaining the induction type stop and hold device according to the present invention, Figs. 2 and 3 are views for further explaining Fig. 1, and Figs. A side view and a top view of an embodiment of the induction type stop and hold device according to the invention, FIG. 6 is a diagram showing an example of a drive circuit connected to the induction type stop and hold device according to the invention, and FIG. FIG. 3 is a diagram illustrating the position of the tip of the secondary conductor and the generation state of the force applied to the secondary conductor. In the figure, 1 is a primary iron core, 2 is a secondary conductor, 6 and 6' are single-phase coils, 9 is a traveling magnetic field generating coil, 10 and 10' are photodetectors, 11 is a conveyance rail, 12 is a wheel, 13 is the carrier.

Claims (1)

[Claims] 1. A magnetic body consisting of a main magnetic pole around which a single-phase AC magnetic field generating coil is wound and a holding magnetic pole magnetically coupled to the main magnetic pole, and a magnetic body that moves relative to the magnetic body. a first eddy current induced in the conductive plate by a magnetic field generated by the main magnetic pole at a position where the conductive plate faces the auxiliary magnetic pole and an end thereof faces the main magnetic pole; The relative movement between the magnetic body and the conductor plate is stopped and maintained by the force generated by the auxiliary magnetic pole and the force generated by the second eddy current induced in the conductor plate by the magnetic field generated by the auxiliary magnetic pole. An induction type stop and hold device characterized by: