WO2011118568A1

WO2011118568A1 - Linear motor

Info

Publication number: WO2011118568A1
Application number: PCT/JP2011/056798
Authority: WO
Inventors: 誠川上
Original assignee: 日立金属株式会社
Priority date: 2010-03-23
Filing date: 2011-03-22
Publication date: 2011-09-29
Also published as: JPWO2011118568A1; TWI519043B; CN102792571A; TW201212490A; JP5741573B2; DE112011100996T5; CN102792571B

Abstract

Disclosed is a linear motor which has a configuration not prone to generate magnetic flux causing short circuits between the poles of different polarity, as in monopolar drive systems, and, by means of using a bipolar drive, is capable of preventing the maximum thrust force from decreasing and has a high ratio of thrust force / magnetomotive force. A linear motor (3) is configured by a movable element (1) penetrating the hollow space of a stator (2). The movable element (1) has a permanent magnet magnetized in one of the movable directions, a soft magnetic yoke, a permanent magnet magnetized in the other of the movable directions, a soft magnetic yoke..., alternately arranged in that order. The stator (2) has multiple magnetic pole teeth arranged in a row on both sides thereof which face the movable element (1), and is formed by winding together with each drive coil (25a, 25b) the respective magnetic pole tooth group comprising multiple magnetic pole teeth.

Description

Linear motor

The present invention relates to a linear motor formed by combining a mover having a plurality of plate-like permanent magnets and an armature (stator) having a drive coil.

High-speed movement in a vertical movement mechanism of a probe (contact element for inspection) in an inspection apparatus of an electronic circuit board or a vertical movement mechanism in a pick-and-place (gripping a component and placing it in a predetermined position) type robot In addition, highly accurate positioning is required. Therefore, the conventional method in which the output of the rotary motor is converted into parallel motion (vertical motion) with a ball screw cannot satisfy such a requirement because the moving speed is low.

Therefore, for such vertical movement, use of a linear motor that can directly extract parallel motion output is being promoted. As a linear motor having a configuration in which a square permanent magnet structure having a large number of plate-like permanent magnets is used as a mover, an armature having a current-carrying coil is used as a stator, and a mover is passed through the stator. Various types have been proposed (for example,

Patent Documents

1, 2, and 3).

Japanese Patent Laid-Open No. 2002-27729 JP 2002-142437 A JP 2005-295708 A

Conventional linear motors have a faster response than ball screws, but because the mass of the mover is large, sufficient thrust can be secured, but the required response speed cannot be achieved. The structure of the linear motor suitable for speeding up is a movable magnet type, and in order to realize a small linear motor having a large thrust, it is necessary to reduce the magnetic pole pitch of the armature.

The magnetic poles of the armature are periodically provided at a specific ratio corresponding to the arrangement period of the permanent magnets of the mover, and a driving coil is wound around each magnetic pole. In order to increase the thrust density of the linear motor, it is necessary to reduce the magnetic pole pitch. However, in such an individual wire structure, the space of the coil to be wound becomes narrow, and when the electric resistance of the coil increases, There is a problem that the fever increases.

In order to solve this problem, a linear motor using a claw pole type (claw teeth type) armature that performs phase batching has been proposed. In this phase batching method, coils are wound around the same part of the armature magnetic poles at once, reducing the number of coils, securing a wide winding area, and lowering the coil electrical resistance. There is an effect to make. However, in this phase rolling method, since the magnetic pole teeth that are the counter electrodes are generally alternately arranged between the N pole and the S pole, especially when the magnetic pole pitch is reduced, the magnetic flux that short-circuits between adjacent magnetic poles increases, The magnetic flux generated from the child cannot be effectively applied to the permanent magnet side of the mover. And when the ratio of the magnetic flux which short-circuits between the magnetic poles of an armature becomes large, there exists a subject that a maximum thrust falls and a thrust physique ratio falls.

A monopolar type (single pole type) linear motor has been proposed for the purpose of preventing a short circuit of magnetic flux between different poles as described above. In this monopolar type, the armature magnetic pole teeth are not arranged alternately as described above, and the polarity excited simultaneously is only one of the N pole and the S pole. ing. In this case, since the armature does not have magnetic pole teeth as a counter electrode, a short-circuit magnetic field is not generated, and the thrust value that is a proportional limit can be increased. This method has an advantage that it can be miniaturized because of its simple structure. However, since the utilization factor of the permanent magnet is halved compared to the bipolar type (bipolar type), the thrust is reduced to ½ when the same driving magnetomotive force is applied as the same permanent magnet arrangement. In addition, since the area of the permanent magnet that contributes to driving is half that of the bipolar type, the load of the permanent magnet increases when the same thrust is generated, and the permeance coefficient of the permanent magnet during driving greatly decreases. There exists a subject that a part will generate | occur | produce and there exists a danger of generating permanent demagnetization.

Conventionally, a mover having a permanent magnet and a soft magnetic yoke has a problem that detent force (stress pulsation generated in the moving direction) due to the high relative magnetic permeability of the soft magnetic material is increased.

The present invention has been made in view of such circumstances, and has a structure in which a magnetic flux that short-circuits between different magnetic poles is unlikely to be generated as in a monopolar drive system, and prevents a decrease in maximum thrust by bipolar driving. An object of the present invention is to provide a linear motor that has a high thrust magnetomotive force ratio.

Another object of the present invention is to provide a linear motor that has a small decrease in permeance coefficient of a permanent magnet when driving magnetomotive force is applied, has high demagnetization resistance, and has improved durability during continuous driving and excellent heat resistance. Is to provide.

Still another object of the present invention is to provide a linear motor that secures a flow of magnetic flux from the yoke of the mover to the magnetic pole teeth and has a structure in which magnetic saturation in the armature hardly occurs.

Still another object of the present invention is to provide a linear motor capable of reducing the weight of the armature by configuring the portion facing the magnetic pole teeth that is less effective as a magnetic flux path in the armature with a light non-magnetic material. There is to do.

Still another object of the present invention is to provide a linear motor that can cancel harmonic components of detent force.

The linear motor according to the present invention is a linear motor in which a plate-shaped movable element is passed through a hollow armature, a plate-shaped permanent magnet magnetized in the moving direction, and a direction in which the magnetization direction is opposite to that of the permanent magnet. Flat plate-like permanent magnets alternately arranged, and a mover in which a yoke of a flat plate-like soft magnetic material is inserted between adjacent permanent magnets, one surface facing the mover and the other The magnetic pole teeth of the soft magnetic material are provided on each of the surfaces so as to oppose every other yoke so that the magnetic pole teeth on one surface and the magnetic pole teeth on the other surface differ by 180 ° in electrical angle, It has a soft magnetic core that serves as a return path of magnetic flux so as to wrap outside the magnetic pole tooth group consisting of magnetic pole teeth on one surface and the magnetic pole tooth group consisting of magnetic pole teeth on the other surface. Drive to apply drive magnetomotive force in a lump Yl is characterized in that it comprises an armature being wound.

The mover of the linear motor according to the present invention has a configuration in which a flat permanent magnet magnetized in the moving direction (longitudinal direction) of the mover and a flat soft magnetic yoke are combined. Permanent magnets magnetized in one direction and permanent magnets magnetized in the other direction opposite to the moving direction are alternately arranged, and the permanent magnets magnetized in one adjacent direction and magnetized in the other direction A soft magnetic yoke is arranged between the permanent magnets. On the other hand, in the armature, magnetic pole teeth are provided to face every other yoke on one surface facing the mover and the other surface corresponding to the arrangement of the yokes of the mover. The magnetic pole teeth and the magnetic pole teeth on the other surface are arranged at different positions of 180 ° in electrical angle. Further, a soft magnetic core serving as a return path of the magnetic flux is provided so as to wrap the outside of a pair of magnetic pole teeth composed of the magnetic pole teeth on one surface and the magnetic pole teeth on the other surface. Further, a drive coil for applying a drive magnetomotive force is wound around each of the pair of magnetic pole teeth.

When the armature configured as described above is passed through the armature configured as described above and a current in the same direction flows through the pair of drive coils, thrust is generated and the mover moves. At this time, all the magnetic pole teeth on one surface side of the armature have the same polarity (for example, N pole), and all the magnetic pole teeth on the other surface side of the armature are opposite to the magnetic pole teeth on the one surface side. It becomes a certain same polarity (for example, S pole). Therefore, the magnetic flux which short-circuits between the adjacent magnetic poles on each surface side is hardly generated. The driving magnetomotive force applied from the drive coil is perpendicular to the moving direction of the mover, but the magnetization direction of the permanent magnet of the mover is parallel to the moving direction. Since it is difficult to apply, the decrease in the permeance coefficient of the permanent magnet is small. As a result, the heat resistant temperature is also increased.

The linear motor of the present invention is a linear motor that combines the advantages of a monopolar type in which a short-circuit magnetic flux between magnetic poles is less likely to be generated, and the advantage of a bipolar type in which both N and S poles of a permanent magnet can be used simultaneously. It is a motor.

In the linear motor according to the present invention, in the magnetic pole teeth, the dimension in the moving direction of the distal end portion near the mover is smaller than the dimension in the moving direction of the base end portion located on the distal side of the mover. It is characterized by that.

In the magnetic pole teeth of the linear motor according to the present invention, the dimension in the moving direction of the tip portion proximal to the mover is smaller than the dimension in the moving direction of the base end portion distal to the mover. Therefore, since the tip of the magnetic pole teeth is narrowed, the magnetic flux surely flows from the yoke of the mover to the magnetic pole teeth. On the other hand, since the base end portion of the magnetic pole teeth is widened, magnetic saturation hardly occurs in the armature.

In the linear motor according to the present invention, the core of the soft magnetic body facing the magnetic pole teeth of the armature, that is, the armature member positioned between the magnetic pole teeth and the magnetic pole teeth is lighter than the soft magnetic body. It is characterized by being replaced with a non-magnetic material.

In the armature of the linear motor according to the present invention, the portion facing the magnetic pole teeth is made of a nonmagnetic material that is lighter than the magnetic material of the magnetic pole teeth. Therefore, compared with the case where the whole is comprised with a magnetic material, an armature is reduced in weight and becomes a lighter linear motor. The portion facing the magnetic pole teeth is a portion that originally has a low magnetic flux density and is less effective as a magnetic flux path. Therefore, even if this portion is made of a non-magnetic material, the generated thrust does not decrease much.

In the linear motor according to the present invention, each of the magnetic pole tooth groups is divided into two groups, and an interval between the two groups is an interval obtained by adding or subtracting a half wavelength of a main detent force harmonic component to an interval between other magnetic pole teeth. It is characterized by doing.

In the armature of the linear motor according to the present invention, the magnetic pole tooth groups having the same pole are divided into two groups, and the interval between these magnetic pole tooth groups is added to the magnetic pole pitch by the half wavelength of the main harmonic component. The interval is subtracted from the magnetic pole pitch. Therefore, the harmonic component is canceled and the detent force is reduced.

The linear motor according to the present invention is characterized in that the main detent force harmonic component is sixth-order, and is configured to add or subtract 1/12 of the field period.

In the armature of the linear motor according to the present invention, the same pole is divided by adding or subtracting 1/12 (τ / 6) of the field period 2τ (2τ = λ) to the magnetic pole pitch. The interval between the magnetic pole teeth. Therefore, the sixth-order detent force harmonic component can be canceled out.

The linear motor according to the present invention is characterized in that the condition of Y <M <T is satisfied when the dimensions of the permanent magnet, the yoke, and the magnetic pole teeth in the moving direction are M, Y, and T, respectively. .

In the linear motor according to the present invention, by satisfying the dimensional conditions as described above, when an excessive magnetomotive force is applied to the core of the armature, the magnetic flux applied from the magnetic pole teeth is counter electroded via the yoke. Therefore, the magnetic field opposite to the magnetization of the permanent magnet is hardly applied, and the demagnetization resistance is increased.

In the present invention, the polarities excited simultaneously at one side and the other side of the armature are always either N poles or S poles as in the case of the monopolar type, so the polarities of adjacent magnetic pole teeth are the same. Therefore, the short circuit of the magnetic flux between different poles can be prevented. Moreover, since the bipolar drive which can utilize effectively the magnetic flux of the permanent magnet of a needle | mover is possible, a high thrust magnetomotive force ratio is realizable. Further, since the degree of influence of demagnetization of the permanent magnet is small when the driving magnetomotive force is applied and the decrease in the permeance coefficient is small, high heat resistance can be exhibited.

In the present invention, the dimension on the tip side of the magnetic pole teeth is made shorter than the dimension on the base end side, so that a flow of magnetic flux to the magnetic pole teeth can be ensured and a structure in which magnetic saturation hardly occurs can be provided.

In the present invention, since the portion facing the magnetic pole teeth of the armature is made of a nonmagnetic material that is lighter than the magnetic material of the magnetic pole teeth, a large thrust can be generated even if the weight is light.

In the present invention, the magnetic pole tooth groups having the same polarity are divided into two groups, and the interval between these magnetic pole tooth groups is set to an interval obtained by adding a half wavelength of the main harmonic component to the magnetic pole pitch or subtracting from the magnetic pole pitch. Therefore, the main harmonic component can be canceled and the detent force can be reduced.

It is a perspective view which shows the structure of the needle | mover used for the linear motor which concerns on this invention. It is sectional drawing which shows the structure of the needle | mover used for the linear motor which concerns on this invention. It is a perspective view which shows the structure of the armature used for the linear motor which concerns on this invention. It is a perspective view which shows the structure of the armature used for the linear motor which concerns on this invention. It is a perspective view which shows the structure of the armature used for the linear motor which concerns on this invention. It is a partial fracture perspective view showing composition of a linear motor concerning the present invention. It is a figure for demonstrating the principle of the thrust generation | occurrence | production of the linear motor which concerns on this invention. It is a figure for demonstrating the function of the yoke of a needle | mover. It is a figure for demonstrating the function of the yoke of a needle | mover. It is a figure for demonstrating the function of the yoke of a needle | mover. It is a figure for demonstrating the flow of the magnetic flux in a comparative example. It is a figure for demonstrating the flow of the magnetic flux in a comparative example. It is a figure for demonstrating the flow of the magnetic flux in a comparative example. It is a figure for demonstrating the flow of the magnetic flux in the example of this invention. It is a graph which shows the relationship between a drive magnetomotive force and a minimum permeance coefficient. It is a graph which shows an example of the relationship between temperature and a demagnetization limit permeance coefficient. It is a figure for demonstrating the cancellation method of the main detent force harmonic component. It is a figure which shows the example of a dimension of a permanent magnet, a yoke, and a magnetic pole tooth. It is a perspective view which shows the structure of other embodiment of the linear motor of this invention. It is a perspective view which shows the structure of other embodiment of the linear motor of this invention. It is a figure which shows distribution of the magnetic flux density which generate | occur | produces in an armature. It is a figure which shows distribution of the magnetic flux density which generate | occur | produces in an armature. It is a figure which shows the flow of the magnetic flux in the armature at the time of a drive. It is a figure which shows the flow of the magnetic flux in the armature at the time of a drive. It is a top view of the Example of the linear motor for the single phase of this invention. It is a side view of the Example of the linear motor for the single phase of this invention. It is a top view which shows the core raw material which comprises an armature. It is a top view which shows the core raw material which comprises an armature. It is a top view which shows the core raw material which comprises an armature. It is a top view which shows the core raw material which comprises an armature. It is a top view which shows the core raw material which comprises an armature. It is a top view which shows the core raw material which comprises an armature. It is a top view which shows the core raw material which comprises an armature. It is a top view which shows the core raw material which comprises an armature. It is a top view which shows the core raw material which comprises an armature. It is a top view which shows the core raw material which comprises an armature. It is a top view which shows the core raw material which comprises an armature. It is a perspective view which shows the core raw material which comprises an armature. It is a perspective view which shows the core raw material which comprises an armature. It is a perspective view which shows the core raw material which comprises an armature. It is a perspective view which shows the core raw material which comprises an armature. It is a perspective view which shows the core raw material which comprises an armature. It is a perspective view which shows the core raw material which comprises an armature. It is a perspective view which shows the core raw material which comprises an armature. It is a perspective view which shows the core raw material which comprises an armature. It is a perspective view which shows the core raw material which comprises an armature. It is a perspective view which shows the core raw material which comprises an armature. It is a perspective view which shows the core raw material which comprises an armature. It is a figure which shows the planar shape of the magnetic pole tooth of an armature. It is a figure which shows the external appearance shape of the Example of the linear motor of this invention. It is a graph which shows the measurement result of the thrust characteristic in the Example of the linear motor of this invention. It is a top view of the other Example of the linear motor for the single phase of this invention. It is a side view of the other Example of the linear motor for the single phase of this invention. It is sectional drawing of the other Example of the linear motor for the single phase of this invention. It is a graph which shows the amplitude of the detent force in each harmonic order by a single phase part and 3 phase synthesis | combination. It is a graph which shows the amplitude of the detent force in each harmonic order by a single phase part and 3 phase synthesis | combination. It is a graph which shows the amplitude of the detent force in each harmonic order by a single phase part and 3 phase synthesis | combination. It is a top view of further another embodiment of the linear motor for a single phase of the present invention. It is a side view of the further another Example of the linear motor for the single phase of this invention. It is sectional drawing of the further another Example of the linear motor for the single phase of this invention. It is a perspective view which shows the structural material of the armature by further another Example of this invention. It is a graph which shows the measurement result of the thrust characteristic in the further another Example of the linear motor of this invention.

Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments thereof.

1A and 1B show a configuration of a mover used in a linear motor according to the present invention, FIG. 1A is a perspective view thereof, and FIG. 1B is a sectional view thereof.

The movable element 1 has a configuration in which two types of flat plate-like

permanent magnets

11a and 11b and a flat plate-like soft magnetic yoke 12 are combined, and the permanent magnet 11a, the yoke 12, the permanent magnet 11b, the yoke 12,. In this order, they are alternately bonded.

1A and 1B, the white arrows shown in the

permanent magnets

11a and 11b indicate the magnetization directions of the

permanent magnets

11a and 11b. Each of the

permanent magnets

11a and 11b is magnetized in the moving direction of the movable element 1 (longitudinal direction of the movable element 1), in other words, in the continuous direction thereof, but the directions of the magnetizations are opposite to each other by 180 degrees. is there. A flat soft magnetic yoke 12 is inserted between the adjacent

permanent magnets

11a and 11b.

In FIG. 1B, white arrows shown on the yokes 12 indicate the flow of magnetic flux, and each yoke 12 has a function of changing the direction of the magnetic flux from the

permanent magnets

11 a and 11 b in the thickness direction of the mover 1. Is responsible. In this mover 1, N poles, S poles, ... are alternately formed on the

yokes

12, 12, ... (see Fig. 1B). That is, yokes 12N serving as N poles and yokes 12S serving as S poles are alternately present. Further, the front and back surfaces of each yoke 12 (yoke 12N, yoke 12S) have the same polarity.

2A to 2C show the structure of the armature used in the linear motor according to the present invention. FIG. 2A is a partial perspective view, FIG. 2B is a partially broken perspective view, and FIG. It is a perspective view.

The armature 2 is composed of a soft magnetic body having a hollow rectangular parallelepiped shape as a whole, and the movable element 1 having the above-described configuration is passed through the hollow portion 21. The armature 2 includes a core portion 22 as a frame that forms a peripheral surface except for the hollow portion 21, and a plurality of upper

magnetic pole teeth

23 a, 23 a, which are arranged from the core portion 22 toward the lower portion of the hollow portion 21. 23a and a plurality of lower

magnetic pole teeth

23b, 23b, 23b arranged from the core portion 22 toward the upper portion of the hollow portion 21. A plurality of upper

magnetic pole teeth

23a, 23a, 23a constitute one magnetic pole tooth group (magnetic pole tooth assembly) 24a, and a plurality of lower

magnetic pole teeth

23b, 23b, 23b constitute the other magnetic pole tooth group (magnetic pole teeth). Tooth assembly) 24b is formed.

The upper

magnetic pole teeth

23a, 23a, 23a on one surface facing the mover 1 and the lower

magnetic pole teeth

23b, 23b, 23b on the other surface facing the mover 1 are respectively in the longitudinal direction of the armature 2 ( The moving elements 1 are arranged so as to be opposed to every other yoke 12 corresponding to the arrangement of the yokes 12 of the moving element 1 in a row. That is, one magnetic pole tooth 23a and one magnetic pole tooth 23b are provided for each field period. Further, the upper magnetic pole teeth 23a and the lower magnetic pole teeth 23b are provided at different positions (positions shifted by half of the field period) in electrical angle of 180 °. Thus, for example, when the upper magnetic pole teeth 23a are opposed to one permanent magnet 11a of the mover 1, the lower magnetic pole teeth 23b are opposed to the other permanent magnet 11b of the mover 1. Become.

In addition, each

magnetic pole tooth

23a, 23b is wide stepwise from the distal end facing the mover 1 toward the distal proximal end. The width of the tip of each

magnetic pole tooth

23a, 23b is preferably longer than the width of the yoke 12 so that the magnetic flux from the yoke 12 of the mover 1 flows reliably.

The core portion 22 is disposed so as to wrap outside the pair of magnetic pole teeth groups 24a and 24b, and serves as a return path of magnetic flux from the

magnetic pole teeth

23a and 23b. One magnetic pole tooth group 24a (

magnetic pole teeth

23a, 23a, 23a) is collectively wound with a drive coil 25a as a winding line, and the other magnetic pole tooth group 24b (

magnetic pole teeth

23b, 23b, 23b) is collectively bundled. A drive coil 25b as a winding wire is wound (see FIG. 2C). The drive coils 25a and 25b are connected so that the energization directions of the drive coil 25a and the drive coil 25b are the same. Black line arrows in FIG. 2C indicate energization directions in the drive coil 25a and the drive coil 25b.

The

magnetic pole teeth

23a, 23a, 23a constituting one magnetic pole tooth group 24a all have the same polarity (for example, N pole), and the

magnetic pole teeth

23b, 23b, 23b constituting the other magnetic pole tooth group 24b are all identical. Polarity (for example, S pole).

1A and B is passed through the hollow portion 21 of the armature 2 shown in FIGS. 2A to 2C, so that the single-phase linear motor (unit for one phase) according to the present invention is obtained. ) 3 is configured. FIG. 3 is a partially broken perspective view showing the configuration of the linear motor 3 according to the present invention.

In the case of this linear motor 3, the armature 2 functions as a stator. Then, by causing current to flow in the same direction through the drive coils 25a and 25b, the mover 1 penetrating through the hollow portion 21 of the armature 2 performs a reciprocating linear motion with respect to the armature 2 (stator).

In the example shown in FIG. 1A, each of the six

permanent magnets

11a and 11b and the twelve yokes 12 are sequentially arranged. However, this is merely an example, and the number thereof may be an arbitrary number. It's okay. In the example shown in FIGS. 2A to 2C, three sets of the upper magnetic pole teeth 23a and the lower magnetic pole teeth 23b are provided. However, this is an example, and the number of sets is arbitrary. Good.

Alternatively, the movable body 1 may be configured by housing a structural body in which the

permanent magnets

11a and 11b and the yoke 12 are bonded in a frame (not shown). However, since the adjacent yokes have different polarities, this frame needs to be a non-magnetic material in order to suppress leakage of magnetic flux between the different polarities. Further, a linear guide rail (not shown) may be provided in such a frame, and a notch for passing the linear guide rail through the hollow portion 21 of the armature 2 may be provided.

Although a single-phase linear motor (unit for one phase) has been described, for example, in the case of configuring a three-phase drive linear motor, the above-described three armatures are represented by magnetic pole pitch × (n + 1/3) or The magnetic pole pitch × (n + 2/3) (where n is an integer) may be arranged in a straight line at intervals, and the mover may be passed through them. In this case, an integer n may be set in consideration of a space in which the drive coil can be accommodated.

Hereinafter, the operation mechanism of the linear motor 3 of the present invention configured as described above will be described with reference to FIG.

When the drive coil 25a and the drive coil 25b of the armature 2 are energized in the direction as shown in FIG. 4 (● is a flow from the back of the paper to the front, × is a flow from the front to the back of the paper) N poles are generated in the upper

magnetic pole teeth

23a, 23a, 23a, and S poles are generated in the lower

magnetic pole teeth

23b, 23b, 23b. On the other hand, in the mover 1, the yoke 12N has N poles on both sides, and the yoke 12S has S poles on both sides.

Therefore, when the mover 1 exists at a position as shown in FIG. 4, a suction force is generated in the direction of the white arrow, and the stress component in the longitudinal direction (moving direction) of the mover 1 is synthesized to become a thrust, The mover 1 moves. At this time, since the N pole and S pole of the yoke 12 both contribute to the generation of thrust, the bipolar drive is performed.

Hereinafter, the effect (bipolar drive function) of the soft magnetic material inserted between the

permanent magnets

11a and 11b of the mover 1 in the yoke 12 will be described with reference to FIGS. 5A to 5C.

As shown in FIG. 5A, when the movable element 1 is present alone, the surface and the back surface of each yoke 12 (yoke 12N, yoke 12S) become magnetic poles having the same polarity, and a magnetic flux is evenly generated between the surface and the back surface. . On the other hand, when the armature 1 is passed through the armature 2, that is, when each yoke 12 (yoke 12N, yoke 12S) faces the

magnetic pole teeth

23a, 23b, as shown in FIG. The magnetic flux generated from the yoke 12 (yoke 12N, yoke 12S) is concentrated on the

magnetic pole teeth

23a, 23b side. For example, in the positional relationship shown in FIG. 5B, the magnetic flux from the yoke 12N as the N pole is concentrated on the upper magnetic pole tooth 23a side, and the magnetic flux from the yoke 12S as the S pole is concentrated on the lower magnetic pole tooth 23b side. . When the electrical angle advances by 180 ° and the positional relationship shown in FIG. 5C is reached, the magnetic flux from the yoke 12N as the N pole is concentrated on the lower magnetic pole tooth 23b side, and from the yoke 12S as the S pole. The magnetic flux concentrates on the upper magnetic pole teeth 23a side.

Therefore, by inserting the soft magnetic yoke 12 between the

permanent magnets

11a and 11b, the magnetic flux generated from the fixed

permanent magnets

11a and 11b can be switched in the vertical direction, and all the

permanent magnets

11a and 11b can be switched. The magnetic flux generated from can contribute to thrust generation, and bipolar drive can be realized. The yoke 12 performs a switching function for switching the magnetic flux from the

permanent magnets

11a and 11b in the vertical direction. For this reason, both the magnetic fluxes generated from the

permanent magnets

11a and 11b can contribute to the generation of thrust. In addition, by adopting such a configuration of magnetic pole teeth, adjacent magnetic pole teeth have the same polarity. Therefore, adjacent to the magnetic flux when the magnetic pole pitch is reduced compared to a general phase batch type armature. Short circuit loss between different poles can be extremely reduced.

Hereinafter, the features of the linear motor of the present invention will be further described.
(1) Improvement of utilization factor of magnetic flux of permanent magnet of mover:
FIG. 6A is a diagram showing the flow of magnetic flux when no yoke is provided as a comparative example of the present invention. When the yoke is not provided, magnetic flux flows vertically from the permanent magnets 41a and 41b, so that unused magnetic flux (magnetic flux surrounded by a broken line in FIG. 6A) is generated and high thrust cannot be obtained. FIG. 6B is a diagram showing the flow of magnetic flux when permanent magnets 51a and 51b magnetized in the thickness direction are used as a comparative example of the present invention. Also in this case, since the magnetic flux flows vertically from the permanent magnets 51a and 51b, a magnetic flux that is not used (magnetic flux surrounded by a broken line in FIG. 6B) is generated, and high thrust cannot be obtained.

As described above, when a mover without a yoke or a mover using a permanent magnet magnetized in the thickness direction is applied to the configuration of the

magnetic pole teeth

23a and 23b of the armature 2 of the present invention, Since the magnetic flux generated from the permanent magnet cannot be switched in the direction of the

magnetic pole teeth

23a and 23b, a magnetic flux that does not contribute to the thrust is generated and the thrust density is lowered. In this invention, the utilization factor of the magnetic flux from

permanent magnet

11a, 11b can be raised by inserting the yoke 12 in the needle | mover 1. FIG.

(2) Prevention of short-circuit magnetic flux between adjacent magnetic pole teeth:
In the configuration of the armature 2 of the present invention, in the arrangement of the magnetic pole teeth, the magnetic pole teeth 23a,... And the magnetic pole teeth 23b,. Oppositely arranged across the child 1. Therefore, since adjacent magnetic pole teeth have the same polarity, the occurrence of short-circuit magnetic flux between different poles is prevented and the bipolar drive of the mover 1 is made possible. Therefore, the magnetic flux generated by the magnetomotive force applied to the drive coils 25a and 25b of the armature 2 can be effectively applied to the mover 1, and the maximum thrust can be increased.

(3) Suppressing the decrease in permeance coefficient of the permanent magnet during driving:
FIG. 7A is a diagram showing the flow of magnetic flux when using, for example,

permanent magnets

61a and 61b magnetized in the thickness direction disclosed in Patent Document 1 as a comparative example of the present invention. The driving magnetic flux (dotted arrow in the figure) applied from the magnetic pole teeth 62 is the thickness direction of the mover 61, and the magnetization directions of the

permanent magnets

61a and 61b (open arrows in the figure) are also the mover 61. That is, the driving magnetic flux from the magnetic pole teeth 62 (dotted arrows in the figure) and the magnetization directions of the

permanent magnets

61a and 61b (open arrows in the figure) are completely opposite to each other. Therefore, a demagnetization region (a region surrounded by a broken line in FIG. 7A) is generated, causing a decrease in permeance coefficient.

In the present invention, as shown in FIG. 7B, the drive magnetic flux (in the drawing) applied to the

permanent magnets

11a and 11b of the mover 1 from the magnetic pole teeth 23a at the position of the electrical angle 90 ° where the largest magnetomotive force is applied during driving. ) Is perpendicular to the moving direction (longitudinal direction) of the mover 1, whereas the magnetization directions of the

permanent magnets

11a and 11b (open arrows in the figure) are the moving direction of the mover 1. Since they are parallel, it is difficult to apply a magnetic flux in the direction in which the

permanent magnets

11a and 11b are demagnetized. Moreover, since the driving magnetic flux (dotted arrow in the figure) from the magnetic pole teeth 23a takes a path to enter the magnetic pole teeth 23b through the yoke 12 under heavy load, a magnetic flux in the direction opposite to the magnetization direction of the

permanent magnets

11a and 11b is generated. Hard to be applied. Accordingly, the resistance to demagnetization is excellent, and a decrease in permeance coefficient can be suppressed. As a result, the operating temperature region can be widened.

FIG. 8 is a graph showing the relationship between the drive magnetomotive force (= drive current × number of turns of the drive coil) and the minimum permeance coefficient in the comparative example shown in FIG. 7A and the example of the present invention shown in FIG. 7B. The comparative example and the example of the present invention are models of the same physique with a magnet thickness: 5 mm, an armature gap: 6.6 mm, and a field period: 18 mm. In FIG. 8, the solid line A represents the characteristics of the comparative example, and the solid line B represents the characteristics of the present invention. From the result of FIG. 8, when a relatively large driving magnetomotive force is applied, the example of the present invention has a lower decrease in the permeance coefficient than the comparative example.

FIG. 9 is a graph showing an example of the relationship between the temperature and the demagnetization limit permeance coefficient (permeance coefficient at which demagnetization of the magnet starts) when a rare earth magnet (Nd—Fe—B magnet) is used for the mover. In accordance with the characteristics shown in FIG. 9, the heat resistant temperature is determined as follows for the comparative example and the example of the present invention when the driving magnetomotive force is 2400 A. In the comparative example, when the driving magnetomotive force is 2400 A, the minimum permeance coefficient is 0.5 based on the characteristics shown in FIG. 8, and the heat resistance temperature is 55 ° C. based on the characteristics shown in FIG. 9 (see A in the figure). On the other hand, in the example of the present invention, when the driving magnetomotive force is 2400 A, the minimum permeance coefficient is 1 from the characteristics shown in FIG. 8, and therefore the heat-resistant temperature is 75 ° C. from the characteristics shown in FIG. As described above, the heat-resistant temperature can be improved in the present invention.

(4) Improvement of assembly of mover:
Conventionally, in a structure (FIG. 7A) in which permanent magnets magnetized in the thickness direction are arranged in the longitudinal direction (moving direction) of the mover, the exposed surfaces of adjacent permanent magnets are different from each other and attracting force is applied. When the mover is assembled, the permanent magnet pops out of the frame and tries to be attracted to the adjacent permanent magnet. For this reason, it is necessary to fix the permanent magnet until the bonding is completed after the permanent magnet is inserted. However, in the present invention, since the permanent magnet is attracted to the yoke, the assembled shape is stable and does not require pressing. Therefore, the assembly property of the mover is improved.

A long non-magnetic yoke extending in the longitudinal direction is further provided at both edges in the width direction of the mover, and the mover yoke is constituted by the soft magnetic yoke and the non-magnetic yoke. You may make it do. The soft magnetic yoke and the non-magnetic yoke can be fixed with screws, an adhesive, caulking, or the like. In such a mover, a soft magnetic yoke and a non-magnetic yoke constitute a mover yoke, and a permanent magnet is attracted and fixed to the soft magnetic yoke, thereby greatly improving the assembly workability. In addition, the configuration can be such that external stress is not directly applied to the permanent magnet. Therefore, it is possible to achieve both assembly workability and structural reliability. In the method of fixing the permanent magnet and the core with the adhesive layer, it is difficult to stably secure the adhesive layer, and the adhesive force is likely to vary. However, such a disadvantage does not occur in the mover of the present invention. .

(5) Reduction of detent power:
When the permanent magnet and the soft magnetic yoke coexist in the mover, the relative permeability periodically changes in the moving direction (field periodic direction), so that higher-order detent force harmonic components become conspicuous. In general, in the case of phase-independent driving, the fundamental wave (the detent force period is the same as the field period) and the second-order and fourth-order harmonics are canceled during the three-phase synthesis, but the third-order, sixth-order, ninth-order, etc. Harmonics that are multiples of 3 will strengthen each other.

FIG. 10 is a diagram for explaining a cancellation method of main detent force harmonic components. In the mover configured as described above, since the sixth harmonic component tends to be larger than the third order, the magnetic pole tooth group having the same polarity is divided into two groups, and these arrangements are divided into τ. / 6 (τ: magnetic pole pitch, τ = λ / 2) larger than the interval between the other magnetic pole teeth (T1 = τ, T2 = τ + τ / 6). As a result, the phase of the detent force generated in the second group of magnetic pole teeth differs by 180 ° in the sixth-order harmonic component, so that the sixth-order harmonic component is canceled and is not output. In addition, although it was made larger than the space | interval of another magnetic pole tooth by (tau) / 6, the same effect is produced even if it makes it narrower than the space | interval of another magnetic pole tooth by (tau) / 6.

Next, the harmonic components of the 12th and higher order can be reduced by arranging the permanent magnets in a skewed manner (arranging the long sides of the permanent magnets at an angle from the direction perpendicular to the moving direction). In this case, the skew angle is 0 to 4 °.

Since the displacement amount of the magnetic pole group and the skew angle of the permanent magnet can be independently changed as described above, it is possible to effectively reduce the detent force with respect to the main harmonic component.

(6) Improvement of demagnetization resistance:
FIG. 11 is a diagram illustrating exemplary dimensions of a permanent magnet, a yoke, and magnetic pole teeth. As shown in FIG. 11, when the dimensions of the permanent magnet, yoke, and magnetic pole teeth in the moving direction of the mover are M, Y, and T, respectively, the relationship of Y <M <T is satisfied. In such a configuration, particularly when the electrical angle at which the applied magnetomotive force is maximum is around 90 °, the magnetic flux applied from the magnetic pole teeth flows to the magnetic pole teeth of the counter electrode via the yoke. Decrease and increase demagnetization resistance.

Hereinafter, other embodiments of the linear motor of the present invention will be described. As described above, the linear motor of the present invention can realize high-speed movement and high-precision positioning in the vertical movement mechanism. In a vertical movement mechanism, it is common to install a linear motor on the movable part of an XY (horizontal direction) table. In such a case, the gravity of the linear motor itself is a load on the XY axis drive side. Therefore, the linear motor is required to be lightweight.

The following embodiment satisfies this requirement. In this embodiment, paying attention to the armature of the linear motor, by replacing the portion where the magnetic flux density does not increase during driving with a light non-magnetic material from a soft magnetic material, the generated thrust is not significantly reduced, The weight is reduced.

FIGS. 12A and 12B show the configuration of another embodiment of the linear motor of the present invention, FIG. 12A is a perspective view of the entire linear motor, and FIG. 12B is a perspective view showing the configuration of a part of the armature. It is.

This single-phase linear motor (single-phase unit) 3a is configured by penetrating the mover 1 through the hollow portion of the armature 2a, similar to the linear motor 3 described above (see FIG. 3). Since the configuration of the mover 1 of the linear motor 3a is exactly the same as the configuration of the mover 1 in the linear motor 3 described above, the description thereof is omitted.

There is a difference in the armature configuration between the linear motor 3 described above and the linear motor 3a. The armature 2 of the linear motor 3 described above is entirely made of a soft magnetic material, but a part of the armature 2a of the linear motor 3a is made of a nonmagnetic material that is lighter than the soft magnetic material. Yes. Specifically, in the core portion 22 of the armature 2 in the linear motor 3, the portions facing the

magnetic pole teeth

23a and 23b (hatched portions) are replaced with a light non-magnetic material such as a magnesium alloy. . Therefore, in the armature 2a, the core portion 22 is only on the side of the

magnetic pole teeth

23a and 23b, and the portion facing the

magnetic pole teeth

23a and 23b is a lightweight support member 22a (see FIG. 12B).

The upper magnetic pole teeth 23a and the lower magnetic pole teeth 23b are provided at different positions of 180 ° in electrical angle except that a light non-magnetic material is used in part. When the teeth 23a are opposed to one permanent magnet 11a of the mover 1, the lower magnetic pole teeth 23b are in a positional relationship such that they face the other permanent magnet 11b of the mover 1. The armature 2a of the linear motor 3a is such that the drive coil 25a is wound around the magnetic pole teeth 23a, and the drive coil 25b is wound around the magnetic pole teeth 23b all together so that currents in the same direction flow through the drive coils 25a and 25b. Other configurations are the same as those of the armature 2 of the linear motor 3.

One magnetic pole tooth group (magnetic pole tooth assembly) composed of a plurality of upper magnetic pole teeth 23a, and the other magnetic pole tooth group (magnetic pole tooth assembly) composed of a plurality of lower magnetic pole teeth 23b Then, since the position is displaced by a half field period with respect to the moving direction of the mover 1, the magnetic flux density generated at the time of driving is small in the core portion at the position facing each

magnetic pole tooth

23a, 23b. Therefore, even if a magnetic material does not exist in this portion and a non-magnetic material is provided, it is difficult to prevent the flow of magnetic flux during driving. Therefore, this portion is replaced with a lightweight nonmagnetic support member 22a.

The armature 2a forms a magnetic flux return path by a magnetic core portion 22 disposed so as to wrap only the portions corresponding to the thickness of the

magnetic pole teeth

23a and 23b of the pair of magnetic pole tooth groups (magnetic pole tooth aggregates). It is a configuration. Since the return path portion of the magnetic flux differs by 180 ° in electrical angle between the pair of magnetic pole tooth groups, the positions do not overlap between the magnetic pole tooth groups. Therefore, by providing a portion overlapping the return path portion of the magnetic flux located on the side surface of the mover 1 and securing a portion where the magnetic flux flows in the moving direction of the mover 1, a closed magnetic path is formed in the armature 2a. Yes. And in order to support the reaction force which generate | occur | produces with a thrust in the part which a magnetic body does not exist, the support member 22a is filled.

FIGS. 13A and 13B are diagrams showing distributions of magnetic flux density generated in the armature when current is passed through the drive coils 25a and 25b (when the maximum current flows at a drive magnetomotive force of 1200A and an electrical angle of 90 °), 14A and 14B are diagrams showing the flow of magnetic flux in the armature during driving. FIGS. 13A and 14A show the distribution of magnetic flux density and the flow of magnetic flux in an armature that is all made of a magnetic material. FIGS. 13B and 14B show that the portion facing the magnetic pole teeth is replaced with a non-magnetic material. The distribution of magnetic flux density in the armature and the flow of magnetic flux are shown.

In an armature composed entirely of a magnetic material, magnetic flux flows as indicated by the dotted arrow in FIG. 14A. Therefore, the magnetic flux density is high in the portion directly under the magnetic pole teeth, but between the magnetic pole teeth of the same pole (enclosed by dotted lines). In the region), the magnetic flux density is small, and the portion facing the magnetic pole teeth hardly contributes as a path for the magnetic flux. Therefore, in the present embodiment, the magnetic material in the portion with low magnetic flux density (the portion facing the magnetic pole teeth) is deleted and replaced with a light non-magnetic material.

In this embodiment, since the magnetic flux flows as shown by the dotted arrow in FIG. 14B, even if the portion facing the magnetic pole teeth is made of a nonmagnetic material, the flow of the magnetic flux is not hindered. The magnetic flux density distribution generated in the magnetic pole teeth shown in FIG. 13B is substantially the same as the magnetic flux density distribution generated in the magnetic pole teeth shown in FIG. 13A. In addition, the increase in magnetic flux density is slight even in the core portion (region surrounded by the dotted line) adjacent to the nonmagnetic material. Therefore, even when a part is replaced with a light non-magnetic material, it is possible to obtain the same level of thrust as compared with the case where all are made of a magnetic material.

In this embodiment, the volume ratio of the nonmagnetic material (supporting member 22a) that can be replaced with the lighter is about 30 to 50%, and the weight of the armature is 20%, depending on the material of the nonmagnetic material to be used. The weight can be reduced by about 40%.

In addition, the operation mechanism in the linear motor 3a of this Embodiment is the same as the operation mechanism in the linear motor 3 mentioned above. Of course, the linear motor 3a also has the characteristics of the linear motor 3 as described in the above (1) to (6).

In the embodiment described above, a lighter linear motor is realized without reducing thrust, by replacing a part (part having a low magnetic flux density) with a light non-magnetic material. Another embodiment capable of reducing the weight of such a linear motor will be described. In this embodiment, one or a plurality of through holes penetrating in the longitudinal direction (moving direction of the mover) are provided in a portion where the magnetic saturation of the armature hardly occurs. Compared to the case where the entire armature is made of a magnetic material, the mass of the armature can be reduced by the amount of the through hole without the magnetic material. Even with such a configuration in which a through hole is provided, the thrust is hardly reduced.

(Example)
Hereinafter, a specific configuration of the linear motor manufactured by the present inventor and characteristics of the manufactured linear motor will be described.

15A and 15B are a top view and a side view of the single-phase linear motor 3 according to the embodiment of the present invention. The movable elements 1 arranged alternately in the order of the permanent magnet 11a, the yoke 12, the permanent magnet 11b, the yoke 12,... Have a plurality of magnetic pole teeth 23a and magnetic pole teeth 23b, respectively. The linear motor 3 is configured by penetrating through the hollow portion 21 of the armature 2 in which the drive coil 25a and the drive coil 25b are collectively wound around the magnetic pole tooth group composed of the magnetic pole tooth group and the magnetic pole tooth group 23b. The

First, as a flat plate-shaped movable element 1 used for the linear motor 3, a movable element 1 including

permanent magnets

11a and 11b having a shape as shown in FIGS. The

permanent magnets

11a and 11b to be used are Nd—Fe—B sintered magnets cut into a flat plate shape having a length of 38 mm, a width of 3 mm, and a thickness of 5 mm. Further, as the soft magnetic yoke 12, a soft iron cut into a flat plate shape having a length of 38 mm, a width of 6 mm, and a thickness of 5 mm was produced.

Then, 54 permanent magnets and 55 yokes are prepared, and bonded with an epoxy adhesive alternately in the order of the permanent magnet 11a, the yoke 12, the permanent magnet 11b, the yoke 12,. A plate-like body having a width of 38 mm and a thickness of 5 mm was produced, and the produced plate-like body was inserted into an aluminum frame to obtain a movable element 1. Although the magnetization directions of the permanent magnet 11a and the permanent magnet 11b are in the moving direction (longitudinal direction) of the mover 1, the directions are opposite to each other (see white arrows in FIGS. 1A and 1B).

Next, core materials AK made of silicon steel plates shown in FIGS. 16A to 16F and FIGS. 17G to 17K (FIGS. 18A to K) were laminated in a predetermined order to produce an armature 2. Each of the core materials A to K has a long side of 90 mm and a short side of 62 mm, but the thickness is 2 mm for the core materials C, D, E, G, H, J, and K, and 3 mm for the core materials A and B. The core materials F and I are 5 mm. Each core material AK has a different hollow shape.

Each of these core materials A to K is configured by cutting a silicon steel plate having a thickness of 0.5 mm into a predetermined shape and bonding it with an epoxy adhesive, and the core material having a thickness of 2 mm is thick. Four pieces of 0.5 mm silicon steel plates are integrated and integrated, and similarly, a core material of 3 mm and 5 mm in thickness is integrated by integrating 10 sheets and 10 sheets respectively.

The stacking order and the number of stacked core materials A to K are as follows.
H + G + F + {E + D + C + B + C + D + E + A} × 3 + E + D + C + I + J + K
In this stacking order, the core materials A to K were overlapped to form a single-phase unit having an outer shape of 62 mm in height, 90 mm in width, and 78 mm in length (see FIGS. 15A and 15B). With this configuration, the magnetic pole teeth on one surface and the magnetic pole teeth on the other surface are arranged to differ by 180 ° in electrical angle. The gap between the magnetic pole teeth (gap) is 6.6 mm.

FIG. 19 shows the planar shape of adjacent

magnetic pole teeth

23a, 23a (23b, 23b) in this unit. In each magnetic pole tooth 23a (23b), the width is gradually increased in three stages from the distal end facing the mover 1 toward the distal proximal end. In consideration of the magnetic flux from the yoke 12 of the mover 1, the width of the most distal portion is 7 mm, which is slightly longer than the width of the yoke 12 (6 mm), and the width of the most proximal portion is the magnetic pole to prevent the occurrence of magnetic saturation. It is 15 mm close to the pitch (18 mm). In addition, although it was set as the structure which changes a width | variety in step shape, it may be comprised in a taper shape so that a width | variety may become wide continuously from the front end side which opposes the needle | mover 1 toward a base end side. good.

For this single-phase unit, the drive coil 25a is wound so as to collectively include the upper magnetic pole group 24a of the unit, and the lower magnetic group 24b of the unit is collectively included. Thus, the drive coil 25b was wound. At this time, a winding frame (bobbin: not shown) that can be inserted into two parts is inserted into the unit and adhered to the magnetic pole group, and then each 1 mm diameter enamel-coated copper wire is wound 100 times. Thus, the drive coil 25a and the drive coil 25b are used.

As described above, when a single-phase armature unit is manufactured by laminating a plurality of silicon steel plates, the stacking direction of the single-phase units (movable) is affected by the variation in the thickness of each silicon steel plate. There is a possibility that the length of the movement direction of the child does not become a desired length. If each unit is not the desired length, cogging is worse. In order to avoid such a situation, if necessary, the longitudinal direction of the armature (movable) using a silicon steel plate having a thickness of about 0.05 to 0.1 mm consisting only of the core portion without providing magnetic pole teeth as a spacer. It is desirable to correct the length of the armature by sandwiching it between one end or both ends of the moving direction of the child.

Three armatures 2 thus prepared were prepared, and the three armatures 2 were straightened so that the relative electrical angle between the adjacent armatures 2 was advanced by 120 ° (specifically, 27 mm). Arranged. Since the interval between the adjacent armatures 2 was set to 27 mm, the total length of these three phases was 288 mm (= 78 mm × 3 + 27 mm × 2). Then, the mover 1 is inserted into the central hollow portion of the three armatures 2 (see FIG. 20) and fixed to the test bench so that the mover 1 can move in the longitudinal direction without contacting the armature 2. did.

A plurality of through-holes penetrating in the longitudinal direction (moving direction of the mover) are provided in the upper core portion and the lower core portion of each armature, and each U-phase, V-phase, and W-phase unit (armature ) With a long shaft. At this time, in order to ensure a desired rigidity and straightness, the diameter of the shaft is preferably 5 mm or more.

The drive coil was connected in series for each phase unit, and the paired drive coils were wired so that the winding direction was the same. And the winding line of each unit of these U phase, V phase, and W phase was made into the star connection, and it connected to the motor controller. Further, a force gauge is connected to the movable element 1 side so that the thrust against the driving magnetomotive force can be measured.

After connecting in this way, the driving current applied to the driving coil was changed and the thrust of the mover 1 was measured. At this time, the thrust was measured by a method of pressing the force gauge against the mover 1. The measurement result of the thrust and the calculation result of the thrust magnetomotive force ratio are shown in FIG. Further, for example, as a comparative example configured as shown in FIG. 7A disclosed in Patent Document 1, a linear motor having the same physique as the embodiment of the present invention is manufactured, and thrust is applied under the same conditions as the embodiment of the present invention. Was measured. The measurement result of the thrust and the calculation result of the thrust magnetomotive force ratio are also shown in FIG.

The horizontal axis in FIG. 21 is the driving magnetomotive force per armature single phase (= driving current × the number of driving coils) [A], and the vertical axis is the thrust [N] and the thrust magnetomotive force ratio [N / A. ]. In the figure, A represents the thrust of the present invention example, B represents the thrust of the comparative example, C represents the thrust magnetomotive force ratio of the present invention example, and D in the figure represents the characteristics of the thrust magnetomotive force ratio of the comparative example. ing.

As shown in FIG. 21, in the proportional area of thrust with respect to the same driving magnetomotive force, the example of the present invention can achieve a thrust about 65% higher than that of the comparative example. Further, the heat resistant temperature can be improved in the example of the present invention. Therefore, the present invention can provide a linear motor suitable for an industrial moving mechanism that requires high-speed movement and high-precision positioning.

Next, another embodiment for reducing the detent force will be described. 22A and 22B are a top view and a side view of a single-phase linear motor 3 according to another embodiment of the present invention, and FIG. 23 is a cross-sectional view of the single-phase linear motor 3 according to another embodiment.

The

permanent magnets

11a and 11b used have a length of 38 mm, a width of 4 mm, and a thickness of 5 mm, and the soft magnetic yoke 12 has a length of 38 mm, a width of 3.5 mm, and a thickness of 5 mm. The magnetic pole pitch τ was 7.5 mm (field period was 15 mm), the widths of the

magnetic pole teeth

23 a and 23 b were 6 mm, and the unequal pitch shift amount was τ / 6 = 1.25 mm. In addition, the skew angle of the

permanent magnets

11a and 11b was set to 2 °.

A linear motor having a configuration in which the spacing between the magnetic pole teeth is uniform and the skew arrangement of the permanent magnet is not performed (Configuration Example 1), and a linear motor having a configuration in which the spacing between the magnetic pole teeth is adjusted but the skew placement of the permanent magnet is not performed (Configuration Example 2) ) And the linear motor (configuration example 3) having a configuration in which the gap between the magnetic pole teeth is adjusted and the permanent magnet is skewed, the amplitude of the detent force at each harmonic order by single-phase and three-phase synthesis was obtained. . The results are shown in FIGS.

In the configuration example 1 shown in FIG. 24A, the detent force of the sixth harmonic component is very large. In the configuration example 2 illustrated in FIG. 24B, the detent force of the sixth harmonic component is reduced, but the detent force of the twelfth harmonic component is large. On the other hand, in the configuration example 3 shown in FIG. 24C, the detent forces of the sixth harmonic component and the twelfth harmonic component are both reduced.

Next, still another embodiment will be described in which a part of the core part of the armature (the part facing the magnetic pole teeth) is replaced with a light non-magnetic body (support member) to reduce the weight. 25A and 25B are a top view and a side view of a single-phase linear motor 3a according to still another embodiment of the present invention, and FIG. 26 is a cross-sectional view of the single-phase linear motor 3a according to still another embodiment. is there. FIG. 27 is a perspective view showing a constituent material of an armature 2a according to still another embodiment.

The overall size of the armature 2a is the same as the embodiment shown in FIGS. 22A and 22B, but the portion facing the magnetic pole teeth (the length of 6 mm in the moving direction of the mover 1: the portion with hatching) The support member 22a is made of a magnesium alloy instead of a magnetic body. The sizes of the

permanent magnets

11a and 11b and the yoke 12 used in the mover 1 are the same as those in the embodiment shown in FIG. 22A, and the pitches of the adjacent

magnetic pole teeth

23a, 23a, 23b, and 23b are also shown in FIG. The same as the embodiment.

A flat plate-like movable element 1 (length: 410 mm, width: 38 mm, thickness: 5 mm) used for the linear motor 3a was produced. Note that the materials of the

permanent magnets

11a and 11b and the yoke 12 to be used and the manufacturing process thereof are the same as those in the embodiment shown in FIGS.

Core member constructed by bonding 12 sheets cut out to a predetermined shape by wire cutting from a 0.5 mm thick silicon steel plate (material 50A800, specific gravity 7.8 g / cm 3 mm) constituting magnetic pole teeth 31 and a lightweight member (support member) 32 cut into a predetermined shape with a thickness of 6 mm from a magnesium alloy (material LA141, Mg-14 mass% Li-1 mass% Al, specific gravity 1.36 g / cm 3 mm). A first armature material 33 was produced. Further, a plurality of sheets cut into a predetermined shape by wire cutting from a silicon steel plate having a thickness of 0.5 mm were bonded with an epoxy adhesive to produce a second armature material 34 to be a side surface portion of the magnetic pole teeth.

And as shown in FIG. 27, the 1st armature material 33 and the 2nd armature material 34 are arrange | positioned alternately, and they are joined, and an external shape is 62 mm in height, 90 mm in width, and 59.75 mm in length. Single-phase units were prepared. A winding frame (bobbin: not shown) that can be inserted into two parts is inserted into the unit and adhered to the magnetic pole group, and then enamel-coated copper wire with a diameter of 1 mm is applied 100 times each to drive coil It was.

The mass of the silicon steel plate and the mass of the magnesium alloy used for the manufactured armature 2a were 111.2 g and 95.57 g per single phase, respectively, and the mass of the entire single phase armature 2a was 1206.77 g.

Three armatures 2a produced in this way are prepared, and the three armatures 2a so that the relative electrical angle between the adjacent armatures 2a advances by 120 ° (specifically 27.75 mm). Were arranged in a straight line. The total length of the three phases was 234.75 mm (= 59.75 mm × 3 + 27.75 mm × 2). Then, the mover 1 is inserted into the central hollow portion of the three armatures 2a (see FIG. 26), and is fixed to the test bench so that the mover 1 can move in the longitudinal direction without contacting the armature 2a. did.

The drive coil was connected in series for each phase unit, and the paired drive coils were wired so that the winding direction was the same. And the wire of each of these units was made into star connection, and it connected to the motor controller. Further, a force gauge is connected to the movable element 1 side so that the thrust against the driving magnetomotive force can be measured.

After connecting in this way, the drive current applied to the drive coil was changed and the thrust of the mover 1 of the linear motor 3a was measured. At this time, the thrust was measured by a method of pressing the force gauge against the mover 1. The measurement result of the thrust and the calculation result of the thrust magnetomotive force ratio are shown in FIG. In addition, a linear motor having the same physique as the linear motor 3a of this embodiment is manufactured as a comparative example except that the entire armature is made of a magnetic material (silicon steel plate), and thrust is measured under the same conditions as the linear motor 3a. did. The measurement result of the thrust and the calculation result of the thrust magnetomotive force ratio are also shown in FIG. In addition, the mass of the armature in the linear motor of this comparative example was 1659.32 g per single phase.

The horizontal axis of FIG. 28 is the driving magnetomotive force (= driving current × number of driving coils) [A] per armature single phase, and the vertical axis is the thrust [N] and the thrust magnetomotive force ratio [N / A]. ]. In the figure, E represents the thrust of the present example, F in the figure represents the thrust of the comparative example, G in the figure represents the thrust magnetomotive force ratio of the present example, and H in the figure represents the characteristic of the thrust magnetomotive force ratio of the comparative example. ing.

As shown in FIG. 28, in this example, thrust characteristics equivalent to those of the comparative example are obtained until the driving magnetomotive force reaches 1600A. In this example, the maximum thrust is about 15% smaller than that of the comparative example, but 27% of the weight is reduced compared to the comparative example, so that the thrust mass ratio exceeds that of the comparative example. ing. Therefore, the linear motor 3a of the present embodiment has an optimum structure for the vertical movement mechanism.

The linear motor 3 in which the entire armature is made of a magnetic material is large in weight but can obtain excellent thrust characteristics. On the other hand, the linear motor 3a in which the portion facing the magnetic pole teeth is made of a light non-magnetic material can reduce the weight, although the thrust characteristics are slightly inferior. Therefore, the linear motor 3 and the linear motor 3a according to the present invention may be properly used according to the environment and application to be used.

In addition, although the case where a magnesium alloy was used as a lightweight nonmagnetic material which comprises the part which opposes a magnetic pole tooth was demonstrated, you may use another material. Conditions required for this material are that it is lightweight and can function as a support member 22a for supporting a reaction force generated by thrust. As materials satisfying these conditions, aluminum alloys, lithium alloys, reinforced plastics, carbon fibers, glass epoxy resins, and the like can be used.

As a part to be replaced with a light non-magnetic material, the one shown in FIG. 27 is an example. A magnetic flux density distribution as shown in FIG. 13A is acquired for the armature composed entirely of a magnetic material, and a portion with a small generated magnetic flux density is reduced based on the acquired magnetic flux density distribution. You may make it replace with. For example, a portion where the magnetic flux density is generated only about 1/3 or less of the saturation magnetic flux density of the core material at the maximum driving time can be replaced with a light non-magnetic material.

Note that, unlike the above-described manufacturing example, the armature can be divided into upper and lower parts. In this case, a predetermined plurality of silicon steel plates are laminated and bonded to produce an upper portion of the armature including the upper magnetic pole teeth, and a predetermined plurality of silicon steel plates are stacked and bonded to the lower side. A lower part of the armature including the magnetic pole teeth is produced, and the upper part and the lower part are integrally coupled to constitute the armature. In this case, a reduction in thrust can be avoided by making the divided portion of the core portion of the armature difficult to cause magnetic saturation. Also, in this manufacturing method, before the upper part and the lower part are joined together, a coiled frame is attached to the upper part magnetic pole group and the lower part magnetic group. Can be made. Therefore, it is easy to increase the space factor to 80% or more. Moreover, assembly workability can also be improved.

DESCRIPTION OF SYMBOLS 1 Movable element 2, 2a Armature 3,

3a Linear motor

11a, 11b Permanent magnet 12 (12N, 12S) Yoke 21 Hollow part 22 Core part 22a Support member (nonmagnetic material)
23a, 23b Magnetic pole teeth 24a, 24b Magnetic

pole teeth group

25a, 25b Drive coil

Claims

In a linear motor in which a flat armature is passed through a hollow armature,
A plate-like permanent magnet magnetized in the moving direction and a plate-like permanent magnet whose magnetization direction is opposite to that of the permanent magnet are alternately arranged, and a plate-like soft magnetic body is formed between adjacent permanent magnets. A mover having a yoke inserted therein;
The magnetic pole teeth of the soft magnetic material are respectively disposed on one surface and the other surface facing the mover so that the magnetic pole teeth on one surface and the magnetic pole teeth on the other surface are 180 ° different in electrical angle. A soft magnetic core that is provided opposite to each other and serves as a return path of magnetic flux so as to wrap outside the magnetic pole tooth group consisting of magnetic pole teeth on one surface and the magnetic pole tooth group consisting of magnetic pole teeth on the other surface And an armature around which a driving coil for applying a driving magnetomotive force is wound around each of the magnetic pole teeth.
2. The magnetic pole tooth according to claim 1, wherein a dimension in the moving direction of a distal end near the movable element is smaller than a dimension in the moving direction of a proximal end located on the distal side of the movable element. The linear motor described.
2. The linear motor according to claim 1, wherein a core of the soft magnetic body facing the magnetic pole teeth of the armature is replaced with a non-magnetic material that is lighter than the soft magnetic body.
Each of the magnetic pole tooth groups is divided into two groups, and the interval between the two groups is an interval obtained by adding or subtracting a half wavelength of the main detent force harmonic component to the interval between the other magnetic pole teeth. The linear motor according to any one of 1 to 3.
5. The linear motor according to claim 4, wherein the main detent force harmonic component is sixth-order, and is configured to add or subtract 1/12 of the field period.
The condition of Y <M <T is satisfied, where the dimensions of the permanent magnet, the yoke, and the magnetic pole teeth in the moving direction are M, Y, and T, respectively. The linear motor described in 1.