Linear motor

Abstract

To provide a technique capable of suppressing vibrations of a movable element with a further simplified support mechanism in a linear motor configured to hold either permanent magnet fields or armatures between the others.SOLUTION: A linear motor 1 comprises: an armature 10 including a coil 12 and a core 11 consisting of a soft magnetic substance; and a field 20 including a permanent magnet 21 or permanent magnets 21A and 21B for generating a field with respect to the armature 10. The armature 10 is disposed so as to be held between a field part 20A and a field part 20B of the field 20. At least one of the armature 10 and the field 20 is configured to have asymmetry between a magnetic actuation caused by the permanent magnet 21 or the permanent magnet 21A between the armature 10 and the field part 20A and a magnetic actuation caused by the permanent magnet 21 or the permanent magnet 21B between the armature 10 and the field part 20B.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to linear motors. [Background technology]

[0002] For example, in a linear motor, a technique is known in which, in order to cancel out the magnetic attraction force between a permanent magnet field and an armature (a core of soft magnetic material), one of the opposing permanent magnet field and the armature is arranged to sandwich the other (see Patent Documents 1 and 2).

[0003] Patent Document 1 discloses a linear motor including an armature as a mover, and a permanent magnet field as a stator arranged so as to sandwich the armature.

[0004] Patent Document 2 discloses a linear motor including a permanent magnet field as a mover, and an armature as a stator arranged so as to sandwich the permanent magnet field. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2011-67030 A [Patent Document 2] Patent No. 5313333 Summary of the Invention [Problem to be solved by the invention]

[0006] However, support mechanisms such as slide rails and linear guides that support the mover usually have a certain range of movement (so-called play) in the axial direction in which the permanent magnet field and the armature face each other. Therefore, if the displacement position of the mover deviates from the reference position where the magnetic attractive forces are offset in the axial direction in which the permanent magnet field and the armature face each other, there is a possibility that a magnetic attractive force will be generated in the mover. In particular, if the displacement position of the mover is repeatedly displaced so as to straddle the above-mentioned reference position, the direction of the magnetic attractive force acting on the mover will frequently switch to a different direction, which may result in vibration of the mover.

[0007] On the other hand, it is possible to suppress vibration by adopting a support mechanism that can keep the movable range of the mover relatively small, but this may lead to the support mechanism becoming more complex and larger, resulting in increased costs.

[0008] In view of the above problems, an object of the present invention is to provide a technology capable of suppressing vibration of a mover with a simpler support mechanism in a linear motor configured to sandwich either a permanent magnet field or an armature with the other. [Means for solving the problem]

[0009] In order to achieve the above object, in one embodiment of the present disclosure, an armature including a coil and a core made of a soft magnetic material; a field including a permanent magnet that generates a magnetic field for the armature; Either one of the armature and the field magnet is disposed so as to be sandwiched between a first portion and a second portion of the other one of the armature and the field magnet, asymmetry is present between a magnetic action by the permanent magnet between any one of the first part and the first section and a magnetic action by the permanent magnet between any one of the first part and the second section, such that a force acting on the mover in the axial direction is either a direction toward the first part or a direction toward the second part over an entire movable range of a mover of the armature and the field magnet in the axial direction in which any one of the first part and the second part face each other, a gap between the one of the first portion and the one of the second portion and a gap between the one of the first portion and the one of the second portion are both changed by movement of the movable element in the movable range in the axial direction. A linear motor is provided.

[0010] In another embodiment of the present disclosure, an armature including a coil and a core made of a soft magnetic material; a field including a permanent magnet that generates a magnetic field for the armature; Either one of the armature and the field magnet is disposed so as to be sandwiched between a first portion and a second portion of the other one of the armature and the field magnet, At least one of the armature and the field magnet is configured to have an asymmetry between a magnetic action by the permanent magnet between the one of the armature and the first part and a magnetic action by the permanent magnet between the one of the armature and the second part, the one of the two is the armature, The other one of the two is the field magnet, The permanent magnets of the first section and the permanent magnets of the second section are configured such that, in an axial direction in which the armature and the first and second sections of the field magnet face each other, the axial force acting on a mover of the armature and the field magnet by the magnetic field of the permanent magnets of the first section and the axial force acting on the mover by the magnetic field of the permanent magnets of the second section are asymmetric. A linear motor is provided.

[0011] In still another embodiment of the present disclosure, an armature including a coil and a core made of a soft magnetic material; a field including a permanent magnet that generates a magnetic field for the armature; Either one of the armature and the field magnet is disposed so as to be sandwiched between a first portion and a second portion of the other one of the armature and the field magnet, At least one of the armature and the field magnet is configured to have an asymmetry between a magnetic action by the permanent magnet between the one of the armature and the first part and a magnetic action by the permanent magnet between the one of the armature and the second part, The one of the two is the field magnet, the other one of the two is the armature, The permanent magnet is configured such that, in an axial direction in which the field magnet faces the first part and the second part of the armature, an axial force acting on a mover of the armature and the field magnet due to a magnetic field acting on the first part from the field magnet and an axial force acting on the mover due to a magnetic field acting on the second part from the field magnet are asymmetric. A linear motor is provided. Effect of the Invention

[0012] According to the above-described embodiment, in a linear motor configured so that either a permanent magnet field or an armature is sandwiched between the other, vibration of the mover can be suppressed with a simpler support mechanism. [Brief description of the drawings]

[0013] [Figure 1] 1 is a diagram illustrating an example of a linear motor according to a first embodiment. [Diagram 2] 6A and 6B are diagrams illustrating the relationship between the displacement of a mover and an attractive force. [Diagram 3] 11 is a diagram illustrating an example of a linear motor according to a second embodiment. FIG. [Figure 4] 6A and 6B are diagrams illustrating the relationship between the displacement of a mover and an attractive force. [Diagram 5] 13A and 13B are diagrams illustrating an example of a linear motor according to a third embodiment. [Figure 6] 6A and 6B are diagrams illustrating the relationship between the displacement of a mover and an attractive force. [Figure 7] 13A and 13B are diagrams illustrating an example of a linear motor according to a fourth embodiment. [Figure 8] 6A and 6B are diagrams illustrating the relationship between the displacement of a mover and an attractive force. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment will be described with reference to the drawings.

[0015] [First embodiment] First, a linear motor 1 according to a first embodiment will be described with reference to FIGS.

[0016] The linear motor 1 may be incorporated in the opening and closing mechanisms of various sliding doors, such as railroad car doors and station platform doors. The linear motor 1 may also be mounted in semiconductor manufacturing equipment, for example. The same applies to the second to fourth embodiments described below.

[0017] <Structure of a Linear Motor> FIG. 1 is a diagram showing an example of a linear motor 1 according to the first embodiment.

[0018] As shown in FIG. 1, the linear motor 1 includes an armature 10 and a field magnet 20.

[0019] The armature 10 is a mover. The armature 10 is arranged to be sandwiched in the Z-axis direction between field magnet portions 20A, 20B of the field magnet 20 arranged to extend along the X-axis direction. The armature 10 is supported in a manner that allows it to move in the X-axis direction by a support mechanism such as a slide rail or a linear guide. In addition, the support mechanism allows the armature 10 a predetermined amount of movement range (so-called play) in the Z-axis direction.

[0020] The armature 10 includes a core 11 and a coil 12 .

[0021] Core 11 functions as a magnetic path for the magnetic field generated by the armature current of coil 12 and the magnetic field from permanent magnet 21 of field magnet 20. Core 11 is made of a soft magnetic material such as an electromagnetic steel sheet or a powder magnetic core. Core 11 is made of the same soft magnetic material throughout and has approximately the same magnetic permeability throughout.

[0022] The core 11 includes a back yoke 11A and teeth 11B.

[0023] The back yoke 11A has a predetermined thickness in the Z-axis direction and is provided to extend in the X-axis direction.

[0024] The teeth 11B include teeth 11B1 and 11B2.

[0025] The teeth 11B1 are provided so as to protrude from the back yoke 11A in the positive direction of the Z axis. In this example, three teeth 11B1 are provided at equal intervals in the X axis direction. The number of teeth 11B1 may be two or less, or may be four or more. The same applies to the teeth 11B2.

[0026] The teeth 11B2 are provided to protrude from the back yoke 11A in the negative direction of the Z axis. In this example, three teeth 11B2 are provided at equal intervals in the X axis direction and at approximately the same positions as the teeth 11B1. The word "approximately" means that, for example, manufacturing errors are allowed, and will be used in the same sense hereinafter.

[0027] The teeth 11B1 and 11B2 are configured to have approximately the same amount of protrusion from the back yoke 11A in the Z-axis direction, so that the armature 10 (core 11) has a shape that is approximately symmetrical in the Z-axis direction with respect to the back yoke 11A (specifically, the central plane of the back yoke 11A in the Z-axis direction).

[0028] The coil 12 includes coils 12A and 12B.

[0029] When an armature current flows through the coil 12A, the coil 12A generates a thrust force for the mover (armature 10) by interacting with the magnetic field generated by the field magnet portion 20A. The coil 12A is formed by winding a conductor around the teeth 11B1. Similar to the teeth 11B1, three coils 12A are provided at equal intervals in the X-axis direction, and each coil 12A is supplied with three-phase AC power of, for example, U-phase, V-phase, and W-phase.

[0030] When an armature current flows through the coil 12B, the coil 12B generates a thrust force for the mover (armature 10) by interacting with the magnetic field generated by the field magnet portion 20B. The coil 12B is formed by winding a conductor around the teeth 11B2. Similar to the teeth 11B2, three coils 12B are provided at equal intervals in the X-axis direction, and each of the coils 12A is supplied with three-phase AC power of, for example, U-phase, V-phase, and W-phase.

[0031] The armature 10 is disposed such that its center plane in the Z-axis direction (hereinafter, "armature reference plane") is biased toward the field magnet portion 20A relative to a center plane in the Z-axis direction between the field magnet portions 20A and 20B (hereinafter, "inter-field central plane") CS. Specifically, the armature 10 is disposed such that its armature reference plane is biased toward the field magnet portion 20A relative to the inter-field central plane CS throughout the entire movable range allowed by the support mechanism.

[0032] The field magnet 20 is a stator. The field magnet 20 is provided so as to extend in the X-axis direction, and the dimension in the X-axis direction is determined in accordance with the amount of movement in the X-axis direction of the armature 10 as a mover.

[0033] The field magnet 20 includes field magnet portions 20A and 20B.

[0034] The field magnet parts 20A, 20B are provided so as to extend in the X-axis direction substantially parallel to each other. A predetermined distance is provided between the field magnet parts 20A, 20B in the Z-axis direction, and this distance is set to be somewhat larger than the dimension of the armature 10 in the Z-axis direction. For example, the distance between the field magnet parts 20A, 20B corresponds to the dimension of the armature 10 in the Z-axis direction plus the movable amount in the Z-axis direction of the support mechanism of the armature 10 (e.g., a slide rail or a linear guide) and a predetermined margin. This allows the armature 10 as a mover to move in the X-axis direction without coming into contact with the field magnet parts 20A, 20B.

[0035] Field magnet portion 20A (an example of a first portion) is disposed to face the positive direction of the Z axis as viewed from armature 10. Field magnet portion 20A generates a magnetic flux that interlinks with coil 12A of armature 10.

[0036] Field magnet portion 20B (an example of a second portion) is disposed so as to face the negative Z-axis direction as viewed from armature 10. Field magnet portion 20B generates a magnetic flux that links with coil 12B of armature 10.

[0037] Each of the field magnet portions 20A and 20B includes a permanent magnet 21 and a back yoke 22.

[0038] The permanent magnets 21 are arranged in the X-axis direction so as to face the armature 10 in the Z-axis direction. For example, the permanent magnets 21 are magnetized in the Z-axis direction facing the armature 10, and are arranged so that the magnetic poles of the surfaces facing the armature 10 are different from those of the other permanent magnets 21 adjacent in the X-axis direction. Also, for example, the permanent magnets 21 may be arranged in a Halbach array in the X-axis direction so that the magnetic flux of the magnetic poles facing the armature 10 is relatively strong.

[0039] The field magnet portion 20A and the field magnet portion 20B are configured so that the magnetic specifications (e.g., shape, size, residual magnetic flux density, etc.) and arrangement specifications (e.g., arrangement positions of the permanent magnets 21 in the X-axis direction and arrangement manner including the presence or absence of a Halbach array, etc.) of the permanent magnets 21 are substantially the same. This allows the field magnet portion 20A and the field magnet portion 20B to generate substantially symmetrical magnetic fields with respect to the inter-field central plane CS in the spaces facing each other in the Z-axis direction.

[0040] The back yoke 22 is disposed adjacent to the surface of the permanent magnet 21 opposite to the surface facing the armature 10 in the Z-axis direction. The back yoke 22 functions as a magnetic path between adjacent permanent magnets 21.

[0041] <Magnetic attractive force acting on the mover> 2 is a diagram showing the relationship between the displacement (Z-axis direction) of the mover (armature 10) and the attractive force. Specifically, it shows the relationship between the displacement position of the armature 10 in the Z-axis direction based on the inter-field central plane CS, and the magnetic attractive force in the Z-axis direction acting on the armature 10 due to the interaction between the armature 10 (core 11) and the field 20 (permanent magnet 21). The displacement position of the armature 10 in the Z-axis direction is defined based on the armature reference plane.

[0042] As described above, the magnetic fields generated by field magnet portion 20A and field magnet portion 20B are substantially symmetrical with respect to inter-field central plane CS, and core 11 of armature 10 has the same magnetic permeability throughout and a shape substantially symmetrical in the Z-axis direction with respect to the armature reference plane. As a result, if the displacement position of armature 10 is on inter-field central plane CS, the magnetic attraction force acting on armature 10 from field magnet portion 20A and the magnetic attraction force acting on armature 10 from field magnet portion 20B become substantially the same and cancel each other out. Therefore, if it is assumed that the displacement position of armature 10 is on inter-field central plane CS as shown in FIG. 2, the magnetic attraction force acting on armature 10 becomes zero.

[0043] Furthermore, when the displacement position of the armature 10 deviates in the positive direction of the Z axis from the inter-field central plane CS, the magnetic attraction force in the positive direction of the Z axis acting on the armature 10 from the field magnet section 20A increases, and the magnetic attraction force in the negative direction of the Z axis acting on the armature 10 from the field magnet section 20B decreases. Furthermore, as the amount of deviation increases, the difference between the magnetic attraction force in the positive direction of the Z axis acting on the armature 10 from the field magnet section 20A and the magnetic attraction force in the negative direction of the Z axis acting on the armature 10 from the field magnet section 20B increases approximately proportionally. Therefore, as shown in Fig. 2, when the displacement position of the armature 10 deviates in the positive direction of the Z axis from the inter-field central plane CS, the magnetic attraction force in the positive direction of the Z axis acting on the armature 10 increases approximately proportionally to the amount of deviation.

[0044] Furthermore, when the displacement position of the armature 10 deviates in the negative direction of the Z axis from the inter-field central plane CS, the magnetic attraction force in the positive direction of the Z axis acting on the armature 10 from the field magnet section 20A decreases, and the magnetic attraction force in the negative direction of the Z axis acting on the armature 10 from the field magnet section 20B increases. Furthermore, as the amount of deviation increases, the difference between the magnetic attraction force in the negative direction of the Z axis acting on the armature 10 from the field magnet section 20B and the magnetic attraction force in the positive direction of the Z axis acting on the armature 10 from the field magnet section 20A increases approximately proportionally. Therefore, as shown in Fig. 2, when the displacement position of the armature 10 deviates in the negative direction of the Z axis from the inter-field central plane CS, the magnetic attraction force in the negative direction of the Z axis acting on the armature 10 increases approximately proportionally to the amount of deviation.

[0045] In this example, as described above, the armature 10 is disposed with the armature reference plane biased toward the field magnet section 20A from the inter-field central plane CS, i.e., shifted in the positive direction of the Z axis, throughout the entire movable range allowed by the support mechanism. As a result, the movable range of the armature 10 is defined as a range biased in the positive direction of the Z axis from the inter-field central plane CS, as shown in Fig. 2. Therefore, the armature 10 can be configured so that a magnetic attractive force in the positive direction of the Z axis always acts on the armature 10 within the movable range allowed by the support mechanism.

[0046] Furthermore, the armature 10 may be disposed such that the armature reference plane is biased toward the field magnet portion 20B from the inter-field central plane CS, that is, shifted in the negative direction of the Z axis, throughout the entire movable range allowed by the support mechanism. In this case, the armature 10 can be configured so that a magnetic attraction force in the negative direction of the Z axis always acts on the armature 10 within the movable range allowed by the support mechanism.

[0047] The armature 10 may be configured such that a magnetic attraction force in either the positive or negative direction of the Z axis acts on the armature 10 over most of its movable range in the Z axis direction, and a magnetic attraction force in the other of the positive or negative direction of the Z axis acts on the remaining part (end) of the movable range. In other words, the armature 10 may have a majority of its movable range included on either the positive or negative side of the Z axis from the inter-field central plane CS, and a remaining part of its movable range included on the other side.

[0048] Thus, in the first embodiment, the armature 10 is configured so as to have an asymmetry between the magnetic action of the permanent magnets 21 between the armature 10 and field magnet portion 20A and the magnetic action of the permanent magnets 21 between the armature 10 and field magnet portion 20B. Specifically, the armature 10 is disposed so as to be biased toward either field magnet portion 20A or field magnet portion 20B in the Z-axis direction.

[0049] This allows the armature 10 to be configured so that the direction of the force acting on the armature 10 in the Z-axis direction is less likely to change. This makes it possible to suppress vibration of the armature 10. Furthermore, there is no need to employ a support mechanism that can suppress the range of motion to be relatively small in order to suppress vibration of the armature 10, and this makes it possible to suppress an increase in the cost of the linear motor 1 including the support mechanism.

[0050] Furthermore, in the first embodiment, the armature 10 may have the above-mentioned asymmetry so that the magnetic attraction force acting on the armature 10 in the Z-axis direction is either toward field magnet portion 20A or toward field magnet portion 20B throughout the entire movable range of the mover in the Z-axis direction.

[0051] As a result, the direction of the force acting on the armature 10 in the Z-axis direction does not change, so vibration of the armature 10 can be further suppressed. Also, since the direction of the force acting on the armature 10 is limited to the positive Z-axis direction or the negative Z-axis direction, it is only necessary to consider the load in the positive Z-axis direction or the negative Z-axis direction in designing the support mechanism. Therefore, a support mechanism with a simpler structure can be adopted than if both loads in the positive Z-axis direction and the negative Z-axis direction were taken into consideration. Therefore, an increase in the cost of the linear motor 1 including the support mechanism can be further suppressed.

[0052] [Second embodiment] Next, a linear motor 1 according to a second embodiment will be described with reference to FIGS.

[0053] The following description will focus on the differences from the first embodiment, and descriptions of the same or corresponding content as in the first embodiment may be simplified or omitted.

[0054] <Structure of a Linear Motor> FIG. 3 is a diagram showing an example of a linear motor 1 according to the second embodiment.

[0055] As shown in FIG. 3, the linear motor 1 includes an armature 10 and a field magnet 20, similar to the first embodiment.

[0056] The armature 10 is a mover, similar to the first embodiment, and includes a core 11 and a coil 12.

[0057] As in the first embodiment, the core 11 is made of the same soft magnetic material throughout and has approximately the same magnetic permeability throughout. The core 11 includes a back yoke 11A and teeth 11B.

[0058] The back yoke 11A, like the first embodiment, has a predetermined thickness in the Z-axis direction and is provided so as to extend in the X-axis direction.

[0059] The teeth 11B are provided to protrude from the back yoke 11A in the positive direction of the Z axis. Three teeth 11B are provided at equal intervals in the X axis direction. The number of teeth 11B may be two or less, or four or more.

[0060] As described below, teeth 11B are arranged such that coils 12A, 12B are overlapped in the Z-axis direction, and therefore the amount of protrusion in the positive direction of the Z-axis is set to be longer than in the first embodiment (tooth 11B1).

[0061] The coil 12 includes coils 12A and 12B.

[0062] Coil 12A is configured by winding a conductive wire around the tip portion of tooth 11B so as to be adjacent to coil 12B in the positive direction of the Z axis when viewed from coil 12B.

[0063] Coil 12B is configured by winding a conductive wire around the base end of tooth 11B so as to be adjacent to coil 12A in the negative Z-axis direction as viewed from coil 12A.

[0064] 3, the armature 10 is disposed so that, at a predetermined displacement position (hereinafter referred to as the "reference displacement position") within its movable range, the armature reference plane is aligned with the inter-field central plane CS. In other words, the armature 10 is disposed at a substantially central position in the Z-axis direction between the field magnet portions 20A and 20B. Meanwhile, the core 11 of the armature 10 has an asymmetric shape with respect to the armature reference plane.

[0065] <Magnetic attractive force acting on the mover> 4 is a diagram showing the relationship between the displacement (Z-axis direction) of the mover (armature 10) and the attractive force. Specifically, it shows the relationship between the displacement position of the armature 10 in the Z-axis direction based on the inter-field central plane CS, and the magnetic attractive force in the Z-axis direction acting on the armature 10 due to the interaction between the armature 10 (core 11) and the field 20 (permanent magnet 21). The displacement position of the armature 10 in the Z-axis direction is defined based on the armature reference plane.

[0066] As described above, the magnetic fields generated by the field magnet portions 20A and 20B are substantially symmetrical with respect to the inter-field central plane CS. On the other hand, the core 11 of the armature 10 has the same magnetic permeability throughout and has an asymmetric shape with respect to the armature reference plane. As a result, even when the displacement position of the armature 10 is on the inter-field central plane CS, the magnetic attraction force acting on the armature 10 from the field magnet portion 20B is greater than the magnetic attraction force acting on the armature 10 from the field magnet portion 20A, and a magnetic attraction force in the negative Z-axis direction acts on the armature 10. This is because the back yoke 11A is provided at the end of the armature 10 in the negative Z-axis direction so as to extend in the X-axis direction.

[0067] Furthermore, when the displacement position of the armature 10 deviates in the positive direction of the Z axis from the inter-field central plane CS, the magnetic attraction force in the negative direction of the Z axis acting on the armature 10 from field magnet section 20B decreases, and the magnetic attraction force in the positive direction of the Z axis acting on the armature 10 from field magnet section 20A increases. Furthermore, as the amount of deviation increases, the difference between the magnetic attraction force in the negative direction of the Z axis acting on the armature 10 from field magnet section 20B and the magnetic attraction force in the positive direction of the Z axis acting on the armature 10 from field magnet section 20A decreases approximately proportionally. Then, when the displacement position of the armature 10 deviates in the positive direction of the Z axis from the inter-field central plane CS to a certain extent, the magnitude relationship between the magnetic attraction force acting on the armature 10 from field magnet section 20B and the magnetic attraction force acting on the armature 10 from field magnet section 20A is reversed. 4, when the displacement position of the armature 10 deviates in the positive direction of the Z axis from the inter-field central plane CS, the magnetic attraction force in the negative direction of the Z axis acting on the armature 10 decreases in proportion to the amount of deviation, and at a certain amount of deviation, the magnetic attraction force becomes zero. Then, when the displacement position of the armature 10 deviates further in the positive direction of the Z axis than the amount of deviation, the magnetic attraction force in the positive direction of the Z axis acting on the armature 10 increases in proportion to the amount of deviation.

[0068] Furthermore, when the displacement position of the armature 10 deviates in the negative direction of the Z axis from the inter-field central plane CS, the magnetic attraction force in the negative direction of the Z axis acting from field magnet section 20B to the armature 10 becomes even larger, and the magnetic attraction force in the positive direction of the Z axis acting from field magnet section 20A to the armature 10 becomes even smaller. Furthermore, as the amount of deviation increases, the difference between the magnetic attraction force in the negative direction of the Z axis acting from field magnet section 20B to the armature 10 and the magnetic attraction force in the positive direction of the Z axis acting from field magnet section 20A to the armature 10 becomes even larger in approximately proportional manner. Therefore, as shown in Fig. 4, when the displacement position of the armature 10 deviates in the negative direction of the Z axis from the inter-field central plane CS, the magnetic attraction force in the negative direction of the Z axis acting on the armature 10 becomes even larger in approximately proportional manner to the amount of deviation.

[0069] In this example, the armature 10 is disposed at approximately the center in the Z-axis direction between the field magnet portions 20A and 20B so that the position in the Z-axis direction corresponding to the inter-field central plane CS is included within the movable range of the support mechanism, as shown in Fig. 3. Therefore, the movable range permitted by the support mechanism of the armature 10 is set to a range extending in the positive Z-axis direction and the negative Z-axis direction centered on the inter-field central plane CS, as shown in Fig. 4.

[0070] In contrast, the magnetic attraction force acting on the armature 10 acts in the negative direction of the Z axis unless the armature 10 is displaced to a certain extent in the positive direction of the Z axis from the inter-field central plane CS, as described above. Therefore, as shown in Fig. 4, the armature 10 can be configured so that a magnetic attraction force in the negative direction of the Z axis always acts on the armature 10 within a movable range allowed by its support mechanism.

[0071] Also, back yoke 11A of armature 10 may be provided at an end in the positive direction of the Z axis, and teeth 11B may be provided to protrude from back yoke 11A in the negative direction of the Z axis. In this case, armature 10 can be configured so that a magnetic attraction force in the positive direction of the Z axis always acts on armature 10 within a movable range allowed by its support mechanism.

[0072] Furthermore, the armature 10 may be configured so that a magnetic attraction force acts in either the positive or negative direction of the Z axis over most of the movable range of the armature 10 in the Z axis direction, and a magnetic attraction force acts in the other of the positive or negative direction of the Z axis over the remaining part (end) of the movable range.

[0073] Thus, in the second embodiment, the armature 10 is configured so as to have an asymmetry between the magnetic action of the permanent magnets 21 between the armature 10 and field portion 20A and the magnetic action of the permanent magnets 21 between the armature 10 and field portion 20B. Specifically, the core 11 of the armature 10 has a magnetically asymmetric structure in the Z-axis direction. More specifically, the core 11 is configured so as to have an asymmetric shape in the Z-axis direction.

[0074] This allows the armature 10 to be configured so that the direction of the force acting on the armature 10 in the Z-axis direction is less likely to change, thereby providing the same functions and effects as the first embodiment.

[0075] In addition, in the second embodiment, the armature 10 may have the above-mentioned asymmetry so that the magnetic attraction force acting on the armature 10 in the Z-axis direction is either toward field magnet section 20A or toward field magnet section 20B throughout the entire movable range of the mover in the Z-axis direction.

[0076] As a result, the direction of the force acting on the armature 10 in the Z-axis direction does not change, and as in the first embodiment, vibration of the armature 10 can be further suppressed, while also further reducing the increase in cost of the linear motor 1 including the support mechanism.

[0077] [Third embodiment] Next, a linear motor 1 according to a third embodiment will be described with reference to FIGS.

[0078] The following description will focus on the differences from the first embodiment, etc., and descriptions of the same or corresponding content as the first embodiment, etc. may be simplified or omitted.

[0079] <Structure of a Linear Motor> FIG. 5 is a diagram showing an example of a linear motor 1 according to the third embodiment.

[0080] As shown in FIG. 5, the linear motor 1 includes an armature 10 and a field magnet 20, similar to the first embodiment and the like.

[0081] The armature 10 is a mover, similar to the first embodiment and the like, and includes a core 11 and a coil 12.

[0082] As in the first embodiment and the like, the core 11 is made entirely of the same soft magnetic material and has approximately the same magnetic permeability throughout.

[0083] The core 11 includes a back yoke 11A and teeth 11B, similarly to the first embodiment and the like.

[0084] Similar to the first embodiment, the teeth 11B include teeth 11B1 and 11B2.

[0085] The armature 10 has a shape similar to that of the first embodiment. However, unlike the first embodiment, the armature 10 is disposed such that the armature reference plane is aligned with the inter-field central plane CS at the reference displacement position. In other words, the armature 10 is disposed at approximately the center in the Z-axis direction between the field magnet portions 20A and 20B.

[0086] The field magnet 20 includes field magnet portions 20A and 20B, similarly to the first embodiment and the like.

[0087] The field portion 20A includes a permanent magnet 21A and a back yoke 22.

[0088] Like the permanent magnets 21 of the first embodiment and the like, the permanent magnets 21A are arranged in the X-axis direction so as to face the positive direction of the Z-axis when viewed from the armature 10. The permanent magnets 21A have substantially the same shape as the permanent magnets 21B, but have a larger residual magnetic flux density than the permanent magnets 21B.

[0089] The field portion 20B includes a permanent magnet 21B and a back yoke 22.

[0090] Like the permanent magnets 21 of the first embodiment and the like, the permanent magnets 21B are arranged side by side in the X-axis direction so as to face the negative Z-axis direction when viewed from the armature 10. As described above, the permanent magnets 21B have substantially the same shape as the permanent magnets 21A, but have a smaller residual magnetic flux density than the permanent magnets 21A.

[0091] The field magnet portion 20A and the field magnet portion 20B are configured so that the arrangement specifications of the permanent magnets 21A, 21B are substantially the same. On the other hand, the magnetic specifications (i.e., residual magnetic flux density) of the permanent magnets 21A, 21B of the field magnet portion 20A and the field magnet portion 20B are different. This allows the field magnet portion 20A and the field magnet portion 20B to generate asymmetric magnetic flux with respect to the inter-field central plane CS in the space facing each other in the Z-axis direction. Specifically, the magnetic flux of the magnetic pole of the surface of the permanent magnet 21A in the field magnet portion 20A facing the armature 10 is larger than the magnetic flux of the magnetic pole of the surface of the permanent magnet 21B in the field magnet portion 20B facing the armature 10.

[0092] <Magnetic attractive force acting on the mover> 6 is a diagram showing the relationship between the displacement (Z-axis direction) of the mover (armature 10) and the attractive force. Specifically, it shows the relationship between the displacement position of the armature 10 in the Z-axis direction based on the inter-field central plane CS, and the magnetic attractive force in the Z-axis direction acting on the armature 10 due to the interaction between the armature 10 (core 11) and the field 20 (permanent magnets 21A, 21B). The displacement position of the armature 10 in the Z-axis direction is defined based on the armature reference plane.

[0093] As described above, the core 11 of the armature 10 has the same magnetic permeability throughout and has a shape that is approximately symmetrical in the Z-axis direction with respect to the armature reference plane. On the other hand, the magnetic fields generated by the field magnet portion 20A and the field magnet portion 20B are asymmetric with respect to the inter-field central plane CS, and the magnetic flux density in the gap between the field magnet portion 20A and the armature 10 is greater than the magnetic flux density in the gap between the field magnet portion 20B and the armature 10. This is because the residual magnetic flux density of the permanent magnet 21A of the field magnet portion 20A is greater than the residual magnetic flux density of the permanent magnet 21B of the field magnet portion 20B. As a result, even if the displacement position of the armature 10 is on the inter-field central plane CS, the magnetic attraction force acting from the field magnet portion 20A to the armature 10 is greater than the magnetic attraction force acting from the field magnet portion 20B to the armature 10, and the magnetic attraction force in the positive direction of the Z-axis acts on the armature 10.

[0094] Furthermore, when the displacement position of the armature 10 deviates in the positive direction of the Z axis from the inter-field central plane CS, the magnetic attraction force in the positive direction of the Z axis acting from the field magnet section 20A to the armature 10 becomes even larger, and the magnetic attraction force in the negative direction of the Z axis acting from the field magnet section 20B to the armature 10 becomes even smaller. Furthermore, as the amount of deviation increases, the difference between the magnetic attraction force in the positive direction of the Z axis acting from the field magnet section 20A to the armature 10 and the magnetic attraction force in the negative direction of the Z axis acting from the field magnet section 20B to the armature 10 becomes even larger in approximately proportional manner. Therefore, as shown in Fig. 6, when the displacement position of the armature 10 deviates in the positive direction of the Z axis from the inter-field central plane CS, the magnetic attraction force in the positive direction of the Z axis acting on the armature 10 becomes even larger in approximately proportional manner to the amount of deviation.

[0095] Furthermore, when the displacement position of the armature 10 deviates in the negative direction of the Z axis from the inter-field central plane CS, the magnetic attraction force in the positive direction of the Z axis acting on the armature 10 from field magnet section 20A decreases, and the magnetic attraction force in the negative direction of the Z axis acting on the armature 10 from field magnet section 20B increases. Furthermore, as the amount of deviation increases, the difference between the magnetic attraction force in the positive direction of the Z axis acting on the armature 10 from field magnet section 20A and the magnetic attraction force in the negative direction of the Z axis acting on the armature 10 from field magnet section 20B decreases approximately proportionally. Then, when the displacement position of the armature 10 deviates to a certain extent in the negative direction of the Z axis from the inter-field central plane CS, the magnitude relationship between the magnetic attraction force acting on the armature 10 from field magnet section 20A and the magnetic attraction force acting on the armature 10 from field magnet section 20B is reversed. 6, when the displacement position of the armature 10 deviates in the negative direction of the Z axis from the inter-field central plane CS, the magnetic attraction force in the positive direction of the Z axis acting on the armature 10 decreases in proportion to the amount of deviation, and at a certain amount of deviation, the magnetic attraction force becomes zero. Then, when the displacement position of the armature 10 deviates further in the negative direction of the Z axis than the amount of deviation, the magnetic attraction force in the negative direction of the Z axis acting on the armature 10 increases in proportion to the amount of deviation.

[0096] In this example, the armature 10 is disposed at approximately the center in the Z-axis direction between the field magnet portions 20A and 20B so that the position in the Z-axis direction corresponding to the inter-field central plane CS is included within the movable range of the support mechanism, as shown in Fig. 5. Therefore, the movable range permitted by the support mechanism of the armature 10 is set to a range extending in the positive Z-axis direction and the negative Z-axis direction centered on the inter-field central plane CS, as shown in Fig. 6.

[0097] In contrast, the magnetic attraction force acting on the armature 10 acts in the positive direction of the Z axis unless the armature 10 is displaced to a certain extent in the negative direction of the Z axis from the inter-field central plane CS, as described above. Therefore, as shown in Fig. 6, the field magnet 20 (field magnet portions 20A, 20B) can be configured so that a magnetic attraction force in the positive direction of the Z axis always acts on the armature 10 within a movable range allowed by its support mechanism.

[0098] Furthermore, the residual magnetic flux density of permanent magnet 21B may be made larger than the residual magnetic flux density of permanent magnet 21A. In this case, field magnet 20 can be configured so that a magnetic attraction force in the negative Z-axis direction always acts on armature 10 within a movable range allowed by its support mechanism.

[0099] Furthermore, the field magnet 20 may be configured so that a magnetic attraction force in either the positive or negative direction of the Z axis acts on the armature 10 over most of its movable range in the Z axis direction, and a magnetic attraction force in the other of the positive or negative direction of the Z axis acts on the remaining part (end) of that movable range.

[0100] Thus, in the third embodiment, the field magnet 20 is configured so that there is asymmetry between the magnetic action of the permanent magnet 21A between the armature 10 and the field magnet portion 20A and the magnetic action of the permanent magnet 21B between the armature 10 and the field magnet portion 20B. Specifically, the permanent magnet 21A of the field magnet portion 20A and the permanent magnet 21B of the field magnet portion 20B are configured so that the magnetic fields acting on the armature 10 are asymmetric in the Z-axis direction. More specifically, the permanent magnet 21A and the permanent magnet 21B have mutually different residual magnetic flux densities.

[0101] This allows the field magnet 20 to be configured so that the direction of the force acting on the armature 10 in the Z-axis direction is less likely to change, thereby achieving the same effects and advantages as in the first embodiment and the like.

[0102] In addition, in the third embodiment, the field magnet 20 may have the above-mentioned asymmetry so that the magnetic attraction force acting on the armature 10 in the Z-axis direction is either toward field magnet portion 20A or toward field magnet portion 20B throughout the entire movable range of the mover in the Z-axis direction.

[0103] As a result, the direction of the force acting on the armature 10 in the Z-axis direction does not change, and as in the first embodiment, etc., vibration of the armature 10 can be further suppressed, while also further suppressing an increase in the cost of the linear motor 1 including the support mechanism.

[0104] [Fourth embodiment] Next, a linear motor 1 according to a fourth embodiment will be described with reference to FIGS.

[0105] The following description will focus on the differences from the first embodiment, etc., and descriptions of the same or corresponding content as the first embodiment, etc. may be simplified or omitted.

[0106] <Structure of a Linear Motor> FIG. 7 is a diagram showing an example of a linear motor 1 according to the fourth embodiment.

[0107] As shown in FIG. 7, the linear motor 1 includes an armature 10 and a field magnet 20, similar to the first embodiment and the like.

[0108] The armature 10 is a mover, similar to the first embodiment and the like, and includes a core 11 and a coil 12.

[0109] As in the first embodiment, the core 11 is made entirely of the same soft magnetic material and has approximately the same magnetic permeability throughout.

[0110] The core 11 includes a back yoke 11A and teeth 11B, similarly to the first embodiment and the like.

[0111] The teeth 11B include teeth 11B1 and 11B2, similarly to the first and third embodiments.

[0112] The armature 10 has the same shape as in the first and third embodiments. As in the third embodiment, the armature 10 is disposed such that the armature reference plane is aligned with the inter-field central plane CS at the reference displacement position. In other words, the armature 10 is disposed at approximately the center in the Z-axis direction between the field magnet portions 20A and 20B.

[0113] The field magnet 20 includes field magnet portions 20A and 20B, similarly to the first embodiment and the like.

[0114] The field portion 20A includes a permanent magnet 21A and a back yoke 22, similar to the third embodiment.

[0115] As in the third embodiment, the permanent magnets 21A are arranged in the X-axis direction so as to face the positive direction of the Z-axis when viewed from the armature 10. Also, unlike the third embodiment, the permanent magnets 21A have substantially the same residual magnetic flux density as the permanent magnets 21B, but are thicker in the Z-axis direction than the permanent magnets 21B.

[0116] The field portion 20B includes a permanent magnet 21B and a back yoke 22, similar to the third embodiment.

[0117] As in the third embodiment, the permanent magnets 21B are arranged side by side in the X-axis direction so as to face the negative Z-axis direction when viewed from the armature 10. Also, unlike the third embodiment, the permanent magnets 21B have substantially the same residual magnetic flux density as the permanent magnets 21A, but are thinner in the Z-axis direction than the permanent magnets 21A.

[0118] The field magnet portion 20A and the field magnet portion 20B are configured so that the arrangement specifications of the permanent magnets 21A, 21B are substantially the same. On the other hand, the magnetic specifications (i.e., thickness in the Z-axis direction) of the permanent magnets 21A, 21B of the field magnet portion 20A and the field magnet portion 20B are different. This allows the field magnet portion 20A and the field magnet portion 20B to generate asymmetric magnetic flux with respect to the inter-field central plane CS in the space facing each other in the Z-axis direction. Specifically, the magnetic flux of the magnetic poles of the surface of the permanent magnet 21A of the field magnet portion 20A facing the armature 10 is larger than the magnetic flux of the magnetic poles of the surface of the permanent magnet 21B of the field magnet portion 20B facing the armature 10.

[0119] <Magnetic attractive force acting on the mover> 8 is a diagram showing the relationship between the displacement (Z-axis direction) of the mover (armature 10) and the attractive force. Specifically, it shows the relationship between the displacement position of the armature 10 in the Z-axis direction based on the inter-field central plane CS, and the magnetic attractive force in the Z-axis direction acting on the armature 10 due to the interaction between the armature 10 (core 11) and the field 20 (permanent magnets 21A, 21B). The displacement position of the armature 10 in the Z-axis direction is defined based on the armature reference plane.

[0120] As described above, the core 11 of the armature 10 has the same magnetic permeability throughout and has a shape that is approximately symmetrical in the Z-axis direction with respect to the armature reference plane. On the other hand, the magnetic fields generated by the field magnet portion 20A and the field magnet portion 20B are asymmetric with respect to the inter-field central plane CS, and the magnetic flux density in the gap between the field magnet portion 20A and the armature 10 is greater than the magnetic flux density in the gap between the field magnet portion 20B and the armature 10. This is because the thickness of the permanent magnet 21A of the field magnet portion 20A in the Z-axis direction is greater than the thickness of the permanent magnet 21B of the field magnet portion 20B in the Z-axis direction. As a result, even if the displacement position of the armature 10 is on the inter-field central plane CS, the magnetic attraction force acting from the field magnet portion 20A to the armature 10 is greater than the magnetic attraction force acting from the field magnet portion 20B to the armature 10, and the magnetic attraction force acts on the armature 10 in the positive direction of the Z-axis.

[0121] Furthermore, when the displacement position of the armature 10 deviates in the positive direction of the Z axis from the inter-field central plane CS, the magnetic attraction force in the positive direction of the Z axis acting from the field magnet section 20A to the armature 10 becomes even larger, and the magnetic attraction force in the negative direction of the Z axis acting from the field magnet section 20B to the armature 10 becomes even smaller. Furthermore, as the amount of deviation increases, the difference between the magnetic attraction force in the positive direction of the Z axis acting from the field magnet section 20A to the armature 10 and the magnetic attraction force in the negative direction of the Z axis acting from the field magnet section 20B to the armature 10 becomes even larger in approximately proportional manner. Therefore, as shown in Fig. 8, when the displacement position of the armature 10 deviates in the positive direction of the Z axis from the inter-field central plane CS, the magnetic attraction force in the positive direction of the Z axis acting on the armature 10 becomes even larger in approximately proportional manner to the amount of deviation.

[0122] Furthermore, when the displacement position of the armature 10 deviates in the negative direction of the Z axis from the inter-field central plane CS, the magnetic attraction force in the positive direction of the Z axis acting on the armature 10 from field magnet section 20A decreases, and the magnetic attraction force in the negative direction of the Z axis acting on the armature 10 from field magnet section 20B increases. Furthermore, as the amount of deviation increases, the difference between the magnetic attraction force in the positive direction of the Z axis acting on the armature 10 from field magnet section 20A and the magnetic attraction force in the negative direction of the Z axis acting on the armature 10 from field magnet section 20B decreases approximately proportionally. Then, when the displacement position of the armature 10 deviates to a certain extent in the negative direction of the Z axis from the inter-field central plane CS, the magnitude relationship between the magnetic attraction force acting on the armature 10 from field magnet section 20A and the magnetic attraction force acting on the armature 10 from field magnet section 20B is reversed. 8, when the displacement position of the armature 10 deviates in the negative direction of the Z axis from the inter-field central plane CS, the magnetic attraction force in the positive direction of the Z axis acting on the armature 10 decreases in proportion to the amount of deviation, and at a certain amount of deviation, the magnetic attraction force becomes zero. Then, when the displacement position of the armature 10 deviates further in the negative direction of the Z axis than the amount of deviation, the magnetic attraction force in the negative direction of the Z axis acting on the armature 10 increases in proportion to the amount of deviation.

[0123] In this example, as shown in Fig. 7, the armature 10 is disposed at approximately the center in the Z-axis direction between the field magnet portions 20A and 20B so that the position in the Z-axis direction corresponding to the inter-field central plane CS is included within the movable range of the support mechanism. Therefore, as shown in Fig. 8, the movable range allowed by the support mechanism of the armature 10 is set to a range extending in the positive Z-axis direction and the negative Z-axis direction centered on the inter-field central plane CS.

[0124] In contrast, the magnetic attraction force acting on the armature 10 acts in the positive direction of the Z axis unless the armature 10 is displaced to a certain extent in the negative direction of the Z axis from the inter-field central plane CS, as described above. Therefore, as shown in Fig. 8, the field magnet 20 (field magnet portions 20A, 20B) can be configured so that a magnetic attraction force in the positive direction of the Z axis always acts on the armature 10 within a movable range allowed by its support mechanism.

[0125] Furthermore, the thickness of permanent magnet 21B in the Z-axis direction may be greater than the thickness of permanent magnet 21A in the Z-axis direction. In this case, field magnet 20 can be configured so that a magnetic attraction force in the negative Z-axis direction always acts on armature 10 within a movable range allowed by its support mechanism.

[0126] Furthermore, the field magnet 20 may be configured so that a magnetic attraction force in either the positive or negative direction of the Z axis acts on the armature 10 over most of its movable range in the Z axis direction, and a magnetic attraction force in the other of the positive or negative direction of the Z axis acts on the remaining part (end) of that movable range.

[0127] Thus, in the fourth embodiment, the field magnet 20 is configured so that there is asymmetry between the magnetic action of the permanent magnet 21A between the armature 10 and the field magnet section 20A and the magnetic action of the permanent magnet 21B between the armature 10 and the field magnet section 20B. Specifically, the permanent magnet 21A of the field magnet section 20A and the permanent magnet 21B of the field magnet section 20B are configured so that the magnetic fields acting on the armature 10 are asymmetrical in the Z-axis direction. More specifically, the permanent magnet 21A and the permanent magnet 21B have shapes that are asymmetrical with each other in the Z-axis direction.

[0128] This allows the field magnet 20 to be configured so that the direction of the force acting on the armature 10 in the Z-axis direction is less likely to change, thereby achieving the same effects and advantages as in the first embodiment and the like.

[0129] In addition, in the fourth embodiment, the field magnet 20 may have the above-mentioned asymmetry so that the magnetic attraction force acting on the armature 10 in the Z-axis direction is either toward field magnet portion 20A or toward field magnet portion 20B throughout the entire movable range of the mover in the Z-axis direction.

[0130] As a result, the direction of the force acting on the armature 10 in the Z-axis direction does not change, and as in the first embodiment, etc., vibration of the armature 10 can be further suppressed, while also further suppressing an increase in the cost of the linear motor 1 including the support mechanism.

[0131] [Other embodiments] Next, another embodiment will be described.

[0132] The above-described embodiments may be combined as appropriate, or modified or changed as appropriate.

[0133] For example, in the second embodiment, the core 11 of the armature 10 may be configured to have asymmetric magnetic permeability instead of asymmetric shape in the Z-axis direction with respect to the armature reference plane, thereby realizing a magnetically asymmetric structure. Specifically, the core 11 may be configured to have the same shape as in the first embodiment, but to have different soft magnetic materials on the Z-axis positive direction side and the Z-axis negative direction side with respect to the armature reference plane.

[0134] Also, for example, the configurations for realizing the asymmetry between the magnetic action by the permanent magnets between the armature 10 and field magnet portion 20A and the magnetic action by the permanent magnets between the armature 10 and field magnet portion 20B in the above-mentioned embodiments may be appropriately combined. That is, at least one of the armature 10 and the field magnet 20 may be configured to have an asymmetry between the magnetic action by the permanent magnets between the armature 10 and field magnet portion 20A and the magnetic action by the permanent magnets between the armature 10 and field magnet portion 20B.

[0135] Also, for example, in the above-described embodiment, the linear motor 1 may be configured such that the armature 10 is the stator and the field magnet 20 is the mover. In this case, the armature 10 may be disposed so as to extend in the X-axis direction in accordance with the range of movement of the field magnet 20 as the mover in the X-axis direction, and the field magnet 20 may be supported by a support mechanism in such a manner as to surround the armature 10 on a plane perpendicular to the X-axis direction (i.e., the YZ plane).

[0136] Also, for example, in the above-described embodiment, the linear motor 1 may be arranged such that the field magnet 20 is sandwiched between a first armature portion (an example of a first portion) and a second armature portion (an example of a second portion) of the armature 10. In this case, at least one of the armature 10 and the field magnet 20 is configured so that there is asymmetry between the magnetic action of the permanent magnet between the field magnet 20 and the first armature portion and the magnetic action of the permanent magnet between the field magnet 20 and the second armature portion.

[0137] Specifically, the field magnet 20 may be disposed so as to be biased toward the first armature portion or the second armature portion from the central plane in the Z-axis direction between the first armature portion and the second armature portion.

[0138] Furthermore, the core 11 included in the first armature section and the core 11 included in the second armature section may have a magnetically asymmetric structure in the Z-axis direction. More specifically, the core 11 included in the first armature section and the core 11 included in the second armature section may be configured to have asymmetric shape or magnetic permeability in the Z-axis direction.

[0139] Furthermore, the permanent magnets 21A, 21B of the field magnet 20 may be configured to have an asymmetry between the magnetic field acting on the first armature section and the magnetic field acting on the second armature section in the Z-axis direction. More specifically, the permanent magnet 21A that generates a magnetic field acting on the first armature section and the permanent magnet 21B that generates a magnetic field acting on the second armature section may have different residual magnetic flux densities. Furthermore, the permanent magnet 21A that generates a magnetic field acting on the first armature section and the permanent magnet 21B that generates a magnetic field acting on the second armature section may have shapes that are asymmetric with each other in the Z-axis direction.

[0140] [Transformation / Change] Although the embodiments have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist described in the claims.

[0141] For example, in the above-described embodiment, the mover of the linear motor 1 may be configured to be movable along a curve rather than along a straight line corresponding to the X-axis direction. In this case, for example, the field magnet portions 20A, 20B arranged to sandwich the armature 10 may have a substantially parallel curved shape when viewed from the Y-axis direction. In this case, "parallel" means that two lines (including curves) maintain an equal distance and do not intersect. [Explanation of symbols]

[0142] 1. Linear motor 10 Armature 11 cores 11A Back Yoke 11B, 11B1, 11B2 Teeth 12, 12A, 12B Coil 20 Field magnet 20A Field magnet section (Part 1) 20B Field magnet section (part 2) 21,21A,21B Permanent magnet

Claims

1. an armature including a coil and a core made of a soft magnetic material; a field including a permanent magnet that generates a magnetic field for the armature; Either one of the armature and the field magnet is disposed so as to be sandwiched between a first portion and a second portion of the other one of the armature and the field magnet, asymmetry is present between a magnetic action by the permanent magnet between any one of the first part and the first section and a magnetic action by the permanent magnet between any one of the first part and the second section, such that a force acting on the mover in the axial direction is either a direction toward the first part or a direction toward the second part over an entire movable range of a mover of the armature and the field magnet in the axial direction in which any one of the first part and the second part face each other, a gap between the one of the first portion and the one of the second portion and a gap between the one of the first portion and the one of the second portion and the one of the second portion are both changed by movement of the mover in the movable range in the axial direction. Linear motor.

2. an armature including a coil and a core made of a soft magnetic material; a field including a permanent magnet that generates a magnetic field for the armature; Either one of the armature and the field magnet is disposed so as to be sandwiched between a first portion and a second portion of the other one of the armature and the field magnet, At least one of the armature and the field magnet is configured to have an asymmetry between a magnetic action by the permanent magnet between the one of the armature and the first part and a magnetic action by the permanent magnet between the one of the armature and the second part, the one of the two is the armature, The other one of the two is the field magnet, The permanent magnet of the first part and the permanent magnet of the second part are configured such that, in an axial direction in which the armature and the first and second parts of the field magnet face each other, an axial force acting on a mover of the armature and the field magnet by a magnetic field of the permanent magnet of the first part and an axial force acting on the mover by a magnetic field of the permanent magnet of the second part are asymmetric. Linear motor.

3. an armature including a coil and a core made of a soft magnetic material; a field including a permanent magnet that generates a magnetic field for the armature; Either one of the armature and the field magnet is disposed so as to be sandwiched between a first portion and a second portion of the other one of the armature and the field magnet, At least one of the armature and the field magnet is configured to have an asymmetry between a magnetic action by the permanent magnet between the one of the armature and the first part and a magnetic action by the permanent magnet between the one of the armature and the second part, The one of the two is the field magnet, the other one of the two is the armature, The permanent magnet is configured such that, in an axial direction in which the field magnet faces the first and second parts of the armature, an axial force acting on a mover of the armature and the field magnet due to a magnetic field acting on the first part from the field magnet and an axial force acting on the mover due to a magnetic field acting on the second part from the field magnet are asymmetric. Linear motor.

4. At least one of the armature and the field magnet has the asymmetry such that a force acting on the mover in the axial direction is directed toward either the first part or the second part over an entire movable range of the mover in the axial direction in which either one of the armature and the field magnet faces the first part and the second part.

4. The linear motor according to claim 2 or 3.

5. The one of the two is disposed biased toward the first part or the second part.

5. A linear motor according to claim 1 .

6. the one of the two is the armature, The other one of the two is the field magnet, The core has a magnetically asymmetric structure in the axial direction in which the armature and the first and second parts of the field magnet face each other.

3. The linear motor according to claim 1 or 2.

7. The core is configured so that its shape or magnetic permeability is asymmetric in the axial direction.

7. The linear motor according to claim 6.

8. The one of the two is the field magnet, the other one of the two is the armature, The core included in the first part and the core included in the second part have a magnetically asymmetric structure in the axial direction in which the field magnet faces the first part and the second part of the armature.

4. The linear motor according to claim 1 or 3.

9. The core included in the first part and the core included in the second part are configured to have asymmetric shape or magnetic permeability in the axial direction.

9. The linear motor according to claim 8.

10. the one of the two is the armature, The other one of the two is the field magnet, The permanent magnets of the first part and the permanent magnets of the second part are configured such that a magnetic field acting on the armature is asymmetric in the axial direction in which the armature and the first and second parts of the field magnet face each other.

3. The linear motor according to claim 1 or 2.

11. The permanent magnet of the first portion and the permanent magnet of the second portion have different residual magnetic flux densities.

11. The linear motor according to claim 10.

12. The permanent magnet of the first portion and the permanent magnet of the second portion have shapes asymmetric with respect to each other in the axial direction.

11. The linear motor according to claim 10.

13. The one of the two is the field magnet, the other one of the two is the armature, The permanent magnet is configured to have an asymmetry between a magnetic field acting on the first part and a magnetic field acting on the second part in the axial direction.

2. The linear motor according to claim 1.

Images