JP2001112231A - Linear induction motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear induction motor having secondary conductors of easy-to-manufacture ladder structure in which thrust operation can be carried out smoothly. SOLUTION: A back yoke having protrusions 10a and a stator unit 8 of ladder structure having secondary conductors 11 arranged perpendicularly to the traveling direction are formed in the same shape as a grating unit and laid on the traveling passage of a carrying vehicle. Primary core 5 of the carrying vehicle traveling in the direction of a guide groove 12 is fixed while inclining against the traveling direction by a skew angle from perpendicularity. When the primary core 5 is conducted, eddy currents are induced in the secondary conductors 11 to generate a thrust for traveling the carrying vehicle. Since the primary core 5 is inclining by a skew angle, fluctuation in the quantity of flux passing through the protrusions 10a and fluctuation of thrust are suppressed to ensure smooth traveling of the carrying vehicle. Furthermore, manufacture of a stator unit 8 can be facilitated because the ladder structure of the secondary conductors 11 is in parallel with the end face of the stator unit 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear induction motor having a secondary conductor formed in a ladder structure.

[0002]

2. Description of the Related Art Among eddy currents induced in a secondary conductor,
As a linear induction motor for increasing the effective component contributing to thrust, a secondary conductor in which cutout grooves are provided at a predetermined pitch while leaving both ends in a direction perpendicular to the moving direction of the mover, that is, a so-called rudder One having a secondary conductor having a structure is disclosed (for example, Japanese Patent Application Laid-Open No. 5-115168).
No.).

[0003] The ladder structure is a notch groove formed at a predetermined pitch in the secondary conductor so as to extend in a direction perpendicular to the propulsion direction, leaving both ends in the width direction of the secondary conductor,
A structure in which the back yoke and the secondary conductor are joined together, and the back yoke is arranged on the surface of the secondary conductor at a predetermined interval from both ends in the width direction of the secondary conductor at a predetermined pitch so as to extend in a direction perpendicular to the propulsion direction. Means a structure formed to be exposed.

In a linear induction motor type transfer device having a secondary conductor formed in a ladder structure, a skew angle is provided from a right angle to a propulsion direction in a ladder structure of the secondary conductor to reduce fluctuations in motor thrust. The technology to reduce is, for example,
It is disclosed in JP-A-2-84049.

[0005] As shown in FIGS. 9A and 9B, the secondary stator 51 has a structure in which a secondary conductor 53 is laminated on a back yoke 52. The convex portions 52a of the back yoke 52 are exposed on the surface of the secondary conductor 53 at a predetermined pitch so as to extend in a direction intersecting the propulsion direction at a predetermined interval from both ends in the width direction of the secondary conductor 53. It is formed as follows. In the configuration of FIGS. 9A and 9B, the protrusion 52a
Is the propulsion direction. The direction in which the convex portion 52a extends is a direction inclined by a skew angle from a right angle to the propulsion direction. The skew angle is set according to an allowable thrust variation.

[0006] When electricity is supplied to the primary core provided on the carrier on the secondary stator 51, an eddy current is generated at a location corresponding to the primary core of the secondary conductor 53, and thrust is generated in the propulsion direction. I do. The reaction force of this thrust becomes the thrust for moving the primary side core, and the carrier travels. Since the secondary stator 51 is provided with a skew angle with respect to a direction orthogonal to the propulsion direction, the variation in thrust is small, and the traveling of the carrier can be smooth.

[0007]

SUMMARY OF THE INVENTION In a linear induction motor type transfer apparatus in which a primary mover of a linear induction motor is provided on a carrier and a secondary stator is arranged on a traveling road surface, the secondary conductor is made of a floor plate. A stator unit joined to a unit body having the same planar shape as a certain square grating unit has been invented by the inventor of the present application.

In the conventional technique, the back yoke 5
2 and the secondary-side conductor 53 are joined to a unit body having the same planar shape as the square grating unit to form a stator unit, the back yoke 52 and the secondary-side conductor 53 are moved in the traveling direction of the carrier. It is necessary to divide the flat surface as an end face. At this time, the back yoke 5
Since the second convex portion 52a or the region of the secondary conductor 53 interposed between the convex portions 52a intersects with the end surface, the structure of the end surface becomes complicated, and it is difficult to manufacture the stator unit and lay it on the traveling road surface. Met.

Further, the projections 52a and 5
If the skew angle is limited so that the region of the secondary-side conductor 53 sandwiched between 2a does not intersect with the end face, it is difficult to set a skew angle that sufficiently brings out the motor performance.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a linear induction motor having a ladder-structured secondary conductor which is easy to manufacture and which can facilitate propulsion operation. It is in.

[0011]

According to a first aspect of the present invention, there is provided a linear induction motor comprising a secondary conductor and a primary core formed in a ladder structure. The side core has a configuration in which the direction in which the magnetic pole extends is inclined by a skew angle from a direction perpendicular to the propulsion direction.

According to a second aspect of the present invention, in the first aspect of the invention, the primary cores are arranged side by side so as to form a pair and symmetrically with respect to a center line of the ladder structure. The direction in which the magnetic poles of the primary core extend is inclined by skew angles opposite to each other.

According to a third aspect of the present invention, in the first or second aspect of the invention, the primary core is provided as a mover on a carrier, and the secondary conductor is provided as a stator on the ground. .

Therefore, according to the first aspect of the present invention,
Since the direction in which the magnetic pole of the primary core extends and the ladder structure of the secondary conductor are obliquely arranged, fluctuations in thrust are reduced even if the ladder structure of the secondary conductor is not tilted from a right angle to the propulsion direction. Is done.

According to the invention described in claim 2, according to claim 1
In addition to the effect of the invention described in (1), the component force of the thrust in the direction perpendicular to the propulsion direction caused by providing the skew angle on the primary side core is offset.

According to the third aspect of the present invention, the first aspect is provided.
Alternatively, in addition to the effect of the invention described in claim 2, the production and laying work of the stator having the secondary side conductor is facilitated.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is embodied in a linear induction motor type transfer apparatus in which a primary core is provided on a carrier as a movable element and a secondary conductor is provided on a traveling path. This will be described with reference to FIGS.

FIG. 2 is a schematic side view of the transport vehicle 1 constituting the transport device. The vehicle 1 has a vehicle body 3 supported by a pair of front and rear bogies 2, and each bogie 2 is equipped with a pair of left and right wheels 4. A primary core 5 of a linear induction motor is provided on a lower surface of each bogie 2. The carrier 1 is equipped with a power control device (not shown) for supplying electricity to the primary core 5.

As shown in FIGS. 3 (a) and 3 (b), the primary side core 5 has a coil 6 wound by distributed winding and a yoke 7 having downward magnetic poles 7a. Is formed. The magnetic pole 7a is formed in a shape extending in a direction perpendicular to the direction in which the magnetic poles 7a are arranged. The direction in which the magnetic poles 7a extend in the primary side core 5 is the carrier 1
Is mounted on the lower surface of the bogie 2 so as to be inclined by a skew angle S from a right angle to the propulsion direction of the bogie.

FIG. 4A shows a secondary stator unit (hereinafter simply referred to as a stator unit) 8 of a linear induction motor.
4 (b) is a cross-sectional view taken along the line BB in FIG. 4 (a).

A base material 9 as a main body of the stator unit 8
Is formed in the same planar shape as the grating unit constituting the floor surface, and the back yoke 10 and the secondary-side conductor 11 are laminated. In the present embodiment, the back yoke 10
Is an iron material, and the secondary-side conductor 11 is formed of an aluminum material. The stator unit 8 is provided with a pair of guide grooves 12.

The base member 9 has a square planar shape, and has upwardly projecting portions 9a at both edges in the width direction perpendicular to the moving direction of the primary core. The back yoke 10 and the secondary-side conductor 11 are formed to have a rectangular planar shape, and the length of the base material 9 in the direction orthogonal to the two projecting portions 9a is the two projecting portions 9a.
The length in the direction parallel to both protruding portions 9 a is shorter than the length between them, and is formed equal to one side of the base material 9. The protrusions 10 a of the back yoke 10 are provided on the surface of the secondary conductor 11 at both ends in the width direction of the secondary conductor 11 at predetermined intervals.
The ladder structure is formed so as to extend in a direction perpendicular to a and to be exposed at a predetermined pitch. Back yoke 1
The 0 and secondary-side conductors 11 are joined to the center between the two projecting portions 9 a of the base material 9.

The two protruding portions 9a of the base member 9 and the back yoke 1
The gap between the zero and the secondary-side conductor 11 constitutes the guide groove 12. The wheel 4 of the transport vehicle 1 is formed to have a width smaller than the width of the guide groove 12, and can roll along the guide groove 12.

As shown in FIG. 1, the stator units 8 are laid side by side so that the guide grooves 12 are located on a straight line.
The traveling path on which the transport vehicle 1 travels is configured. Seen from the top,
The primary core 5 of the carrier 1 is provided with a convex portion 10 of a back yoke 10.
It is arranged so as to correspond to the range of the length a. The skew angle S of the primary side core 5 is different from the convex part 10a and the magnetic pole 7a.
Is set in accordance with the pitch and allowable thrust reduction.

Next, the operation of the linear induction motor configured as described above will be described. When power is supplied to the coil 6 of the primary core 5 by the power control device of the carrier 1, an eddy current is generated at a location corresponding to the primary core 5 of the secondary conductor 11, and thrust is applied to the secondary conductor 11. appear. The reaction force of this thrust becomes a thrust for moving the primary core 5, and the carrier 1 travels along the guide groove 12.

The primary core 5 is arranged so that the direction in which the magnetic pole 7a extends and the direction in which the convex portion 10a of the back yoke 10 extends are inclined by the skew angle S. When the side core 5 moves, there is no case where the magnetic pole 7a and the projection 10a fall into a positional relationship where there is no overlapping portion when viewed from above. For this reason, the magnetic pole 7a and the projection 10a
The fluctuation of the amount of magnetic flux passing through is small.

Since the secondary-side conductor 11 is formed in a ladder structure, the region of the secondary-side conductor 11 sandwiched between the protrusions 10a of the back yoke 10 is moved in the propulsion direction which greatly contributes to thrust. Many eddy current components flow in the perpendicular direction.

As described above, even if the position of the primary side core 5 moves as the carrier 1 travels, the protrusion 1 of the back yoke 10
0a, there is little variation in the amount of magnetic flux passing through
The fluctuation of the eddy current that occurs in the air is small. Therefore, the primary core 5
The fluctuation of the thrust for moving is reduced.

The direction in which the protrusion 10a of the back yoke 10 extends is parallel to the end face of the stator unit 8 facing the adjacent stator unit 8, so that the structure of the end face is simple. This facilitates the production and installation work of the stator unit 8 having a square planar shape.

This embodiment has the following effects. (1) Since the direction in which the magnetic pole 7a extends from the primary side core 5 is inclined from a right angle to the propulsion direction by a skew angle,
Even if the ladder structure of the secondary-side conductor 11 of the stator unit 8 is not tilted at right angles to the propulsion direction, the variation in thrust can be reduced.

(2) Since it is not necessary to provide a skew angle in the ladder structure of the secondary-side conductor 11, it is easy to manufacture the stator unit 8 divided into the same shape as the grating unit.

(3) Since the stator unit 8 is formed in the same shape as the grating unit, the stator unit 8 can be easily laid, and the running path can be easily changed by replacing with another grating unit.

(4) Since it is easy to manufacture the stator unit 8 which requires a large number of laying on the traveling path, the manufacturing cost of the transport device can be reduced. (5) Since the skew angle S is set according to the mounting state of the primary core 5 of the carrier 1, the skew angle can be changed by changing the mounting angle of the primary core 5 of the carrier 1. Therefore, it is easy to change the skew angle.

The embodiment is not limited to the above, and may be embodied as follows, for example. As shown in FIG. 5, one of the paired primary cores 5 is tilted by a skew angle from a right angle to the propulsion direction, and the other is tilted by a skew angle opposite to the skew angle of the one primary core 5, It may be configured to be symmetrically mounted. The thrust generated by the primary core 5 inclined by the skew angle is a force oblique to the propulsion direction, and includes a component force perpendicular to the propulsion direction. When the primary core 5 is solely used, the component force of the thrust in the direction perpendicular to the propulsion direction is equal to the wheel 4 and the guide groove 12.
Increase the friction between. In the present embodiment, the component force in the direction perpendicular to the direction of propulsion of the generated thrust is opposite to each other in the two primary cores 5 forming a pair. Pair 2
By symmetrically mounting the primary cores 5, these component forces cancel each other out, and an increase in friction between the wheel 4 and the guide groove 12 can be prevented.

As shown in FIGS. 6 (a), 6 (b) and 7, the primary core 5 may be installed on a road surface on which it travels, and the back yoke 10 and the secondary conductor 11 may be attached to the transport vehicle 1. . In this case, since the primary side core 5 is installed on the road surface, it is not necessary to supply power to the carrier 1 for supplying power to the primary side core 5. Further, the manufacture of the mover including the secondary-side conductor 11 is facilitated.

As shown in FIG. 8A, the primary side core 5 is formed so that the planar shape of the outer shape is substantially a parallelogram, and the direction in which the magnetic pole 7a of the yoke 7 extends with respect to the propulsion direction. The magnetic poles 7a may be formed so as to be inclined from the right angle by the skew angle and arranged in the propulsion direction. Compared to the case where the magnetic poles 7a are arranged side by side in a direction perpendicular to the direction in which the magnetic poles 7a extend,
In the case of this embodiment, the magnetic pole 7a can be configured to be long, and the carrier 1
Each time the vehicle travels, the area where the magnetic pole 7a and the convex portion 10a intersect can be widened, so that more magnetic flux is
Can pass through. Therefore, it is possible to improve the thrust.

As shown in FIG. 8 (b), one of the primary cores 5, whose paired outer shapes are parallelograms, is set so that the direction in which the magnetic pole 7 a of the yoke 7 extends is the propulsion direction. A configuration may be used in which the skew angle is formed from a right angle to a skew angle, and the other is tilted by a skew angle opposite to the skew angle of one primary core 5 and arranged side by side in a direction perpendicular to the propulsion direction. Also in this case, the thrust can be improved, and the component forces in the direction perpendicular to the direction in which the generated thrust is propelled cancel each other, so that an increase in friction between the wheel 4 and the guide groove 12 can be prevented.

The shape of the convex portion 10a of the back yoke 10 is not limited to a shape extending in a direction perpendicular to the propulsion direction.
When the back yoke 10 and the secondary conductor 11 are divided by a plane perpendicular to the propulsion direction, if the convex portion 10a or the region of the secondary conductor 11 sandwiched between the convex portions 10a is not divided, the convex portion 10a may be shaped to extend in a direction inclined from a right angle to the propulsion direction at an angle smaller than a predetermined skew angle. Then, the primary core 5 is tilted and mounted in a direction opposite to the angle at which the protrusion 10a is tilted, so that the direction in which the magnetic pole 7a extends and the direction in which the protrusion 10a extends crosses at a predetermined skew angle. In this case, the angle at which the primary core 5 is inclined from a right angle to the propulsion direction can be reduced.

The stator unit 8 is connected to the secondary conductor 11
Alternatively, a hole or a groove extending in a direction perpendicular to the propulsion direction may be formed, and no back yoke may be provided.
Also, a similar hole or groove is formed in the secondary side conductor 11,
No projection is formed on the back yoke 10, and the back yoke 1
0 and the secondary side conductor 11 may be laminated. In these cases, the labor and cost of manufacturing can be reduced.

The back yoke of the stator unit 8 and the base material may be integrally formed. In this case, the back yoke and the base material can be formed by one member, and the labor and cost of manufacturing can be reduced.

The back yoke 10 may be made of a magnetic metal or alloy such as nickel or stainless steel other than iron. The secondary conductor 11 may be made of a non-magnetic metal or alloy such as copper or brass, for example, other than aluminum.

The shape of the stator unit 8 from the upper surface may be rectangular other than square. ○ The linear induction motor involves a linear motion such as a reach drive of a reach-type forklift, a drive of a slide fork of a stacker crane, a lift of an elevator, a drive of a needle bar and a feed mechanism of an electric sewing machine, in addition to the propulsion of a traveling vehicle. It may be used for driving the device.

The technical idea grasped from the embodiment and not described in the claims will be described below together with its effects. (1) In the invention according to claim 3, the back yoke and the secondary-side conductor are joined to each other, and the back yoke is provided on the surface of the secondary-side conductor at a predetermined distance from both ends in the width direction of the secondary-side conductor. In this case, the stator unit was formed so as to be exposed at a predetermined pitch so as to extend in a direction perpendicular to the propulsion direction, and was laminated on the main body of the stator unit, and the stator unit was formed in the same shape as the grating unit. In this case, since the stator unit can be laid in the same manner as the grating unit, the laying operation is easy, and it is possible to easily cope with a change in the traveling path by replacing the stator unit with another grating unit.

(2) In the first or second aspect of the present invention, the primary core is provided on the ground as a stator, and the secondary conductor is provided on a carrier as a movable element. In this case, it is easy to manufacture the mover including the secondary-side conductor.

(3) In the first aspect of the present invention,
A structure in which the back yoke and the secondary conductor are joined together, and the back yoke is provided on the surface of the secondary conductor at a predetermined pitch so as to extend in a direction perpendicular to the propulsion direction at a predetermined interval from both ends in the width direction of the secondary conductor. When the back yoke and the secondary conductor are divided by a plane perpendicular to the propulsion direction, the back yoke is sandwiched between the portion exposed on the surface of the secondary conductor and the back yoke. The shape of the part of the back yoke exposed on the surface of the secondary conductor extends in a direction inclined at right angles to the propulsion direction at an angle smaller than a predetermined skew angle so that the area of the secondary conductor is not divided. The part of the back yoke exposed on the surface of the secondary conductor is tilted and attached to the primary core in a direction opposite to the angle of inclination, and the direction in which the magnetic poles extend and the part of the back yoke exposed on the surface of the secondary conductor. No The direction that is configured such that the angle of intersection has a predetermined skew angle. In this case, the angle at which the primary core is inclined from a right angle to the propulsion direction can be reduced.

[0046]

As described in detail above, according to the first aspect of the present invention, the ladder of the secondary conductor is mounted by tilting the primary core by the skew angle in order to reduce the variation in thrust. There is no need to tilt the structure by the skew angle. Therefore, it is possible to form a linear induction motor in which the secondary conductor can be easily manufactured and the propulsion operation can be performed smoothly.

According to the invention described in claim 2, according to claim 1,
In addition to the effects of the invention, the component force of the thrust in the direction perpendicular to the propulsion direction caused by mounting the primary side core at an angle of skew can be cancelled, and the operation of the mover side can be performed smoothly.

According to the third aspect of the present invention, the first aspect is provided.
Alternatively, in addition to the effect of the second aspect of the present invention, it is easy to manufacture and lay the stator having the secondary-side conductor.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing the relationship between a primary core and a stator unit.

FIG. 2 is a schematic side view of a transport vehicle.

FIG. 3A is a schematic plan view showing the relationship between the structure of a primary core provided on a carrier and a guide groove provided on a stator unit, and FIG. 3B is a schematic cross-sectional view thereof.

4A is a plan view of a stator unit according to an embodiment, and FIG. 4B is a cross-sectional view taken along line BB.

FIG. 5 is a schematic plan view of a primary core and a stator unit of another embodiment.

FIG. 6A is a schematic plan view showing a relationship between a secondary-side conductor provided in a carrier according to another embodiment and a guide groove of a stator unit, and FIG. 6B is a schematic cross-sectional view thereof.

FIG. 7 is a schematic plan view showing a relationship between a secondary conductor and a primary core according to another embodiment.

FIGS. 8A and 8B are schematic plan views showing a relationship between a primary side core and a fixed unit provided in a carrier according to another embodiment.

FIG. 9A is a plan view of a secondary-side conductor according to the related art, and FIG. 9B is a cross-sectional view taken along the line IX-IX.

[Explanation of symbols]

Reference numeral 1 denotes a carrier, 5 denotes a primary core, 7a denotes a magnetic pole, 11 denotes a secondary conductor, and S denotes a skew angle.

Claims (3)

[Claims] 1. A linear induction motor comprising a secondary conductor and a primary core formed in a ladder structure, wherein a direction in which the magnetic pole of the primary core extends is inclined by a skew angle from a right angle to a propulsion direction. Linear induction motor configured. 2. The primary cores are arranged side by side so as to form a pair and symmetrically with respect to a center line of the ladder structure,
2. The linear induction motor according to claim 1, wherein the directions in which the magnetic poles of the respective primary cores extend are inclined by skew angles opposite to each other. 3. The carrier according to claim 1, wherein the primary core is provided as a mover on a carrier, and the secondary conductor is provided as a stator on the ground.
Or the linear induction motor according to claim 2.