JP7707979B2 - Vernier motor - Google Patents

Description

This disclosure relates to a linear vernier motor.

A linear vernier motor comprises a stator with multiple magnetic poles arranged in a straight line, and a mover with multiple magnetic poles arranged in a straight line and combined to move linearly with respect to the stator. The stator is, for example, an armature with magnetic poles having coils. The mover is, for example, a field magnet with magnetic poles having permanent magnets and magnetic parts. Furthermore, the vernier motor is configured to obtain a magnetic deceleration effect during magnetic transmission between the stator and the mover, and thus can obtain a high linear thrust (see, for example, Patent Document 1).

Patent No. 5812680

However, in conventional general configurations, the combination of the number of pole pairs of each magnetic pole of the stator and the mover that can achieve the desired low detent of the vernier motor is limited. In other words, in order to achieve the desired low detent of the vernier motor, the number of magnetic poles is limited, and the thrust and size of the motor become gradual, so the inventors have been considering a configuration that can fine-tune them.

The objective of this disclosure is to provide a vernier motor that achieves low detent and allows easy adjustment of the motor's thrust and size.

The vernier motor that solves the above problem includes an armature (20) having a plurality of linearly arranged first magnetic pole portions (21) of a pole pair including a coil (22) and a magnetic member (23), and a field element (30) having a plurality of linearly arranged second magnetic pole portions (32) of a pole pair including a permanent magnet (33, 33a to 33c) and a magnetic portion (34), and is configured to obtain a magnetic deceleration effect during magnetic transmission between the first and second magnetic pole portions based on current flow through the coil, and generates a linear thrust force in the axial (L1) direction by the relative linear movement of the armature and the field element. a linear vernier motor that can obtain a linear vernier motor, wherein the field element is composed of a polar anisotropic magnet or a Halbach array magnet that allows magnetic flux to pass between the permanent magnet and the adjacent magnetic portion, and at least a part of a first back side portion (31a) located on the back side of the permanent magnet with respect to the armature and a second back side portion (31b) located on the back side of the magnetic portion with respect to the armature are composed of a non-magnetic portion, and the first back side portion (31a) and the second back side portion (31b) are separate members .

According to the above configuration, the permanent magnets of the field element are composed of polar anisotropic magnets or Halbach array magnets, and magnetic flux is induced so that it mainly flows between adjacent magnetic parts. Here, if part of the magnetic flux passes through the rear side parts of the permanent magnets and magnetic parts and acts on magnetic parts and permanent magnets that are farther away than the adjacent ones, it becomes ripples, which can be a factor in increasing the ripples. In consideration of this, by configuring at least a part of the rear side parts of the permanent magnets and magnetic parts of the armature as non-magnetic parts, it is possible to suppress the generation of unnecessary magnetic flux that leads to an increase in ripples. In other words, the ripples are suppressed to be small and low detent is achieved. In addition, even if the rear side parts of the permanent magnets and magnetic parts are non-magnetic parts, the impact on the thrust of the motor is small, and it is possible to maintain the thrust. In this way, maintaining the thrust and suppressing the ripple rate without relying on the combination of the number of magnetic poles leads to a greater degree of freedom in the combination of the number of magnetic poles, and it can be said that it is easy to fine-tune the thrust and physical size of the motor.

FIG. 2 is a cross-sectional view showing the vernier motor in the first embodiment. FIG. 2 is a cross-sectional view showing a stator and a mover in the first embodiment. FIG. 2 is an enlarged cross-sectional view showing a portion of a stator and a mover in the first embodiment. FIG. 2 is an exploded perspective view showing a mover in the first embodiment. 11 is a graph showing a comparison of thrust and ripple rate of each type of vernier motor. FIG. 11 is a cross-sectional view showing a stator and a mover in a second embodiment. FIG. 11 is an exploded perspective view showing a mover in a second embodiment. FIG. 11 is a cross-sectional view showing a stator and a mover in a third embodiment. FIG. 11 is an exploded perspective view showing a mover in a third embodiment. FIG. 11 is a perspective view showing a mover in a modified example. FIG. 11 is an enlarged cross-sectional view showing a part of a stator and a mover in a modified example. FIG. 11 is an enlarged cross-sectional view showing a part of a stator and a mover in a modified example. FIG. 11 is an enlarged cross-sectional view showing a part of a stator and a mover in a modified example. FIG. 11 is an enlarged cross-sectional view showing a part of a stator and a mover in a modified example. FIG. 11 is a cross-sectional view showing a stator and a mover in a modified example. FIG. 11 is a cross-sectional view showing a stator and a mover in a modified example. FIG. 11 is a cross-sectional view showing a stator and a mover in a modified example. FIG. 11 is a cross-sectional view showing a stator and a mover in a modified example. FIG. 11 is a perspective view showing a mover in a modified example. FIG. 11 is a perspective view showing a mover in a modified example. FIG. 11 is a perspective view showing a mover in a modified example.

First Embodiment
A first embodiment of the vernier motor will be described below.
(Overall configuration of the vernier motor M1)
As shown in Fig. 1, the vernier motor M1 of this embodiment is configured as a linear type vernier motor that obtains a linear thrust force. The vernier motor M1 includes a housing 10, a stator 20, and a mover 30. In this embodiment, the stator 20 side is configured as an armature, and the mover 30 side is configured as a field element. The vernier motor M1 is configured such that the mover 30 moves linearly back and forth relative to the stator 20 along its own axis L1 direction (hereinafter simply referred to as the axial direction).

(Configuration of the housing 10)
The housing 10 includes a cylindrical case 11 extending along the axial direction, and a pair of disk-shaped end housings 12 closing both ends of the case 11. A bearing 13 is provided in the center of each end housing 12. The bearings 13 support the mover 30 so that the mover 30 is movable along the axial direction.

(Configuration of stator 20)
1 and 2, the stator 20 is fixed to the inner peripheral surface of the case 11. The stator 20 is configured to have a generally circular ring shape extending along the axial direction as a whole. The axial length of the stator 20 is shorter than the length of the case 11 in the same direction, and is configured to be, for example, about 1/3 to 1/2 the length.

In this embodiment, the stator 20 has six magnetic pole portions 21 (first magnetic pole portions). The magnetic pole portions 21 are arranged in a straight line in the axial direction. Each magnetic pole portion 21 is configured with a magnetic pole pair. Each magnetic pole portion 21 has a coil 22, a magnetic plate 23 (magnetic member), and a permanent magnet 24.

The coil 22 has a wound shape in which the conductor wire is wound around the axis L1. The coil 22 will be described including an insulator (not shown) made of insulating resin material. Magnetic plates 23 are arranged in contact with both sides of the coil 22 in the axial direction. The magnetic plates 23 are made of a magnetic metal material such as a soft magnetic material in the shape of a circular ring. The outer periphery of the magnetic plate 23 is in contact with the inner periphery of the case 11. The inner periphery of the magnetic plate 23 faces the outer periphery of the mover 30 with a predetermined gap therebetween.

The outer peripheral surface of the permanent magnet 24 is disposed in contact with the radially inner side of the coil 22. The permanent magnet 24 is made in an annular shape from a single magnetic material. In addition, both end faces of the permanent magnet 24 in the axial direction are disposed in contact with the magnetic plates 23 on both sides of the coil 22. The inner peripheral surface of the permanent magnet 24 and the inner peripheral edge of the magnetic plate 23 are flush with each other.

As shown in FIG. 3, the permanent magnet 24 is magnetized such that the magnetic flux in the axial center portion is locally oriented in the radial direction on the inner circumferential surface facing the mover 30. In this embodiment, the permanent magnet 24 is configured as a polar anisotropic magnet in which the inner circumferential surface of the central portion, divided into three equal parts in the axial direction, appears as a north pole, and both axial end faces that abut against the magnetic plate 23 appear as south poles. In this embodiment, one-third of the axial length of the permanent magnet 24 is configured to be equal to the thickness of two magnetic plates 23.

As shown in FIG. 2, the stator 20 is arranged such that the magnetic plates 23 of the magnetic pole portions 21 adjacent to each other in the axial direction are in contact with each other. Between adjacent magnetic pole portions 21, two magnetic plates 23 overlap. All six magnetic pole portions 21 used in the stator 20 are of the same configuration, including the permanent magnets 24. Furthermore, the coils 22 of the six magnetic pole portions 21 are set as U phase, -W phase, V phase, -U phase, W phase, and -V phase, in that order from one axial side. The six coils 22 are each supplied with a corresponding three-phase current. The stator 20 made of the armature of this embodiment is configured in this manner.

(Configuration of the mover 30)
As shown in Figures 1 and 2, the mover 30 is configured in a generally circular rod shape extending long along the axial direction. The axial center portion of the mover 30 is disposed radially inside the stator 20. The mover 30 is provided so as to be capable of linear reciprocating motion in the axial direction relative to the stator 20. The mover 30 includes a shaft portion 31 and a magnetic pole portion 32 (second magnetic pole portion). The shaft portion 31 is configured to be longer than the case 11 in the axial direction. Both axial side portions of the shaft portion 31 are supported by the bearings 13 of each end housing 12. A plurality of magnetic pole portions 32 are provided integrally with the axial center portion of the shaft portion 31.

The magnetic pole parts 32 are arranged on the outer circumferential surface of the shaft part 31 in a straight line in the axial direction. The magnetic pole parts 32 are configured so that the total axial length of the magnetic pole parts 32 is longer than the length of the stator 20 in the same direction. In this embodiment, there are eight magnetic pole parts. Five of the eight magnetic pole parts 32 are configured so that the axial length is equal to the length of the stator 20 in the same direction. In other words, the six magnetic pole parts 21 of the stator 20 and the five magnetic pole parts 32 of the mover 30 are always in a radially opposed relationship. If the number of pole pairs of the armature is "m" and the number of pole pairs of the field magnet is "n", then "n = m ± 1" holds for the vernier motor. The number of pole pairs of the magnetic pole parts 21 of the stator 20, which is the armature, is "m = 6", and the number of pole pairs of the magnetic pole parts 32 of the mover 30, which is the field magnet, is "n = 5", which is satisfied in this embodiment.

Each magnetic pole section 32 has a permanent magnet 33 and a magnetic section 34. The eight magnetic pole sections 32 as a whole are arranged such that the permanent magnets 33 and the magnetic sections 34 alternate in the axial direction. Eight permanent magnets 33 are provided, and nine magnetic sections 34 are provided, arranged on both sides of the permanent magnets 33. The permanent magnets 33 and the magnetic sections 34 are set to have the same axial length. One permanent magnet 33 and one adjacent magnetic section 34 function as one pole pair of magnetic pole sections 32.

The permanent magnet 33 is made into a ring shape from a single magnetic material. Both end faces of the permanent magnet 33 in the axial direction are arranged in contact with the magnetic parts 34 on both sides. As shown in FIG. 3, the permanent magnet 33 is magnetized such that the magnetic flux in the central axial part is locally oriented in the radial direction on the outer circumferential surface facing the stator 20. In this embodiment, the permanent magnet 33 is configured as a polar anisotropic magnet in which the outer circumferential surface of the central part, divided into three equal parts in the axial direction, appears as an S pole, and both axial end faces in contact with the magnetic parts 34 appear as N poles.

As shown in Figures 2 and 4, the inner portion 31a of the permanent magnet 33, which constitutes part of the shaft portion 31, is made of a non-magnetic metal material such as aluminum or SUS in this embodiment. In this embodiment, the permanent magnet 33 and the inner portion 31a are made by integrally combining different materials.

The magnetic part 34 is made of a magnetic metal material in an annular shape. The outer peripheral surface of the magnetic part 34 is flush with the outer peripheral surface of the permanent magnet 33. In this embodiment, the inner part 31b of the magnetic part 34, which constitutes part of the shaft part 31, is made of a magnetic metal material. In this embodiment, the magnetic part 34 and the inner part 31b are made as an integrated part from a single magnetic metal material such as a soft magnetic material.

The entire magnetic pole portion 32, which has eight permanent magnets 33 and nine magnetic portions 34, is housed within a tubular member 35. The tubular member 35 is made of a non-magnetic metal material such as aluminum or SUS, and is cylindrical in shape. The tubular member 35 is fixed to each of the magnetic portions 34 located on both sides in the axial direction, for example, and is constructed as one unit. This is how the mover 30, which is made up of the field element of this embodiment, is constructed.

(Manufacturing Procedure of the Movable Member 30)
As shown in Figs. 1 and 4, in the mover 30 of this embodiment, a disk-shaped part X1 in which the permanent magnet 33 and the inner part 31a are integrally manufactured, and a disk-shaped part X2 in which the magnetic part 34 and the inner part 31b are integrally manufactured are used. Eight parts X1 including the permanent magnet 33 and seven parts X2 including the magnetic part 34 are used. In addition, a part X3 in which a disk part consisting of the magnetic part 34 and the inner part 31b is integrally manufactured is used at the shaft end part constituting the end side part of the shaft part 31. Two parts X3 are used. Then, the parts X1 and the parts X2 are alternately inserted and stacked in the cylindrical member 35, and the parts X3 are arranged on both sides in the axial direction. The permanent magnets 33 and the magnetic parts 34 are arranged alternately, and the permanent magnets 33 and the inner parts 31a, 31b of the magnetic part 34 are integrated as the shaft part 31. Both axial ends of the cylindrical member 35 are fixed to the magnetic portion 34 of the disk portion of the part X3 by crimping or the like, thereby forming an integrated mover 30.

(Operation of this embodiment)
The operation of this embodiment will be described.
In the vernier motor M1 of this embodiment, due to the above structure, when the mover 30 moves, for example, in one axial direction by the amount of one magnetic pole portion 32, the magnetic flux density distribution in the air gap moves in the other axial direction by the amount of six magnetic pole portions 21 of the stator 20 (in this case, one block). Since the six magnetic pole portions 21 of the stator 20 and the five magnetic pole portions 32 of the mover 30 are set to the same length, the movement of the mover 30 due to one periodic change when current is applied to each coil 22 of the stator 20 is the amount of one magnetic pole portion 32. In other words, the movement of the mover 30 is decelerated to 1/5. In the vernier motor M1, which obtains such a magnetic deceleration effect during magnetic transmission from the stator 20 to the mover 30, a high thrust motor output can be obtained.

In this embodiment, a polar anisotropic magnet or the like is used for the permanent magnet 33 of the mover 30, and magnetic flux is induced so that it travels mainly between adjacent magnetic parts 34. Here, if part of the magnetic flux passes through the shaft part 31 on the radially inner side of the permanent magnet 33 and magnetic part 34 and acts on the magnetic part 34 and permanent magnet 33 that are farther away than the adjacent ones, it becomes a ripple, which can be a factor in increasing the ripple. Therefore, in this embodiment, the inner part 31a of the permanent magnet 33 that constitutes part of the shaft part 31 is made a non-magnetic part, and the travel of magnetic flux between the distant magnetic part 34 and permanent magnet 33 is suppressed. In this way, the path of the magnetic flux in the mover 30 is optimized, and the generation of unnecessary magnetic flux that leads to increased ripple is suppressed.

Figure 5 shows the thrust and ripple rate of the vernier motor in each aspect. The first embodiment is shown as "A1". For the comparative example "B" and comparative example "C" for comparison, the comparative example "C" does not use the above-mentioned permanent magnet 33 as the magnetic pole part of the mover, but is composed only of the magnetic part 34. In addition, the comparative example "B" also uses the above-mentioned permanent magnet 33 and magnetic part 34 as the magnetic pole part of the mover, but the shaft part 31 such as the inner part 31a of the permanent magnet 33 is composed of a magnetic metal material. Each aspect is compared with the thrust of the comparative example "C" as "1", the magnitude of the ripple per unit thrust as the ripple rate, and the ripple rate of the comparative example "C" as "1". The combination of the number of magnetic poles of the stator and the number of magnetic poles of the mover is set to the same setting.

In comparison example "B", a sufficiently high thrust force was obtained compared to comparison example "C", and the ripple rate was also significantly suppressed. However, in the configuration of comparison example "B", the shaft portion 31, such as the inner portion 31a of the permanent magnet 33, is made of a magnetic material, so the magnetic flux that leads to ripples is not suppressed, and there is still room for improvement, particularly with regard to the ripple rate.

In contrast, in the first embodiment "A1", it is possible to suppress the ripple rate more sufficiently than in the comparative example "B". Furthermore, the combination of the number of magnetic poles of the stator 20 and the number of magnetic poles of the mover 30 in this embodiment is a combination that can originally reduce the ripple rate. In other words, when the number of magnetic poles of the stator 20 and the mover 30 is changed, there are some combinations in which the ripple rate increases. Reducing the ripple rate without relying on the combination of the number of magnetic poles, as in this embodiment, also leads to a greater degree of freedom in the combination of the number of magnetic poles. Moreover, in the first embodiment "A1", a high thrust force equivalent to that of the comparative example "B" can be obtained, and a high thrust force can be maintained.

In addition, FIG. 5 also shows the thrust and ripple rates of a second embodiment "A2" and a third embodiment "A3" which will be described later.
(Effects of this embodiment)
The effects of this embodiment will be described.

(1-1) The permanent magnet 33 of the mover 30 in this embodiment is composed of a polar anisotropic magnet, and magnetic flux is induced so that it mainly flows between the adjacent magnetic parts 34. As mentioned above, if part of the magnetic flux passes through the inner parts 31a, 31b, which are the rear side parts of the permanent magnet 33 and the magnetic part 34, and acts on the magnetic part 34 and the permanent magnet 33 that are farther away than the adjacent ones, it becomes a ripple, which can be a factor in increasing the ripple. In consideration of this, in this embodiment, the inner part 31a of the permanent magnet 33 is configured as a non-magnetic part, so that the generation of unnecessary magnetic flux that leads to an increase in ripple is suppressed. In other words, the ripple is suppressed to be small, and low detent can be achieved. In addition, by making the inner part 31a of the permanent magnet 33 a non-magnetic part, the impact on the thrust of the vernier motor M1 is small, and the thrust can be maintained. Maintaining thrust and suppressing the ripple rate in this way without relying on the combination of magnetic pole numbers increases the degree of freedom in the combination of magnetic pole numbers, making it easy to fine-tune the thrust and size of the vernier motor M1.

(1-2) The mover 30 is integrally constructed including a portion where part X1, which is a first part including the permanent magnet 33, and part X2, which is a second part including the magnetic part 34, are stacked in the axial direction. In other words, the mover 30 is divided into multiple parts in the axial direction, and the relatively small parts X1 and X2 are handled, which is expected to have the effect of making the mover 30 easier to manufacture.

(1-3) The parts X1 and X2 that constitute a part of the mover 30 are housed in the cylindrical member 35 and integrated together. This is expected to have the following advantages: the parts X1 and X2 can be easily assembled, and the shape of the integrated part that uses the parts X1 and X2 can be easily regulated.

(1-4) The entire inner portion 31a of the annular permanent magnet 33 is non-magnetic, so unnecessary magnetic flux that crosses the shaft portion 31 can be effectively suppressed. Ripples can be suppressed more reliably.

Second Embodiment
A second embodiment of the vernier motor will now be described.
(Configuration of the Stator 20 and the Movable Part 30)
6 and 7, the vernier motor M2 of this embodiment has a stator 20 configured similarly to that of the first embodiment. In the mover 30, the inner portion 31a of the permanent magnet 33 constituting a part of the shaft portion 31 and the inner portion 31b of the magnetic portion 34 are changed.

In this embodiment, the inner portion 31a of the permanent magnet 33 is made of a magnetic metal material. The permanent magnet 33 and the inner portion 31a are made by combining different materials together. In this embodiment, the inner portion 31b of the magnetic part 34 is made of a non-magnetic metal material. The magnetic part 34 and the inner portion 31b are made by combining different materials together. In other words, the inner portions 31a, 31b of the permanent magnet 33 and the magnetic part 34 are switched from those in the first embodiment. In this embodiment, too, the part X1 including the permanent magnet 33 and the part X2 including the magnetic part 34 are inserted into the cylindrical member 35, and the mover 30 is integrally formed.

(Operation of this embodiment)
The operation of this embodiment will be described.
In this embodiment as well, the inner portion 31b of the magnetic portion 34 constituting part of the shaft portion 31 of the mover 30 is made non-magnetic, suppressing the passage of magnetic flux between the distant magnetic portion 34 and the permanent magnet 33. In this configuration as well, as in the first embodiment, the path of the magnetic flux in the mover 30 is optimized, suppressing the generation of unnecessary magnetic flux that leads to increased ripple.

Therefore, as shown in FIG. 5 for the second embodiment "A2," it is possible to sufficiently suppress the ripple rate, as in the first embodiment. This also leads to a greater degree of freedom in the combination of the number of magnetic poles of the stator 20 and the mover 30. Moreover, it is possible to maintain a high thrust force in the second embodiment "A2."

(Effects of this embodiment)
The effects of this embodiment will be described.
(2-1) In this embodiment as well, it is possible to obtain the same advantages as the advantages (1-1) to (1-3) of the first embodiment.

(2-2) Because the entire inner portion 31b of the annular magnetic portion 34 is non-magnetic, this embodiment also effectively suppresses unnecessary magnetic flux that crosses the shaft portion 31. As with the first embodiment, it is possible to more reliably suppress ripples.

Third Embodiment
A third embodiment of the vernier motor will now be described.
(Configuration of the Stator 20 and the Movable Part 30)
As shown in Figures 8 and 9, the vernier motor M3 of this embodiment has a stator 20 configured in the same manner as in the first embodiment. In the mover 30, the permanent magnet 33 constituting a part of the shaft portion 31 and the inner portions 31a, 31b of the magnetic portion 34 are both made of non-magnetic metal material. The permanent magnet 33 and the inner portion 31a are made by integrally combining different materials. The magnetic portion 34 and the inner portion 31b are also made by integrally combining different materials. In this embodiment, too, the part X1 including the permanent magnet 33 and the part X2 including the magnetic portion 34 are inserted into the cylindrical member 35 to integrally form the mover 30.

(Operation of this embodiment)
The operation of this embodiment will be described.
In this embodiment as well, the permanent magnet 33 and the inner portions 31a, 31b of the magnetic portion 34 constituting a part of the shaft portion 31 of the mover 30 are both non-magnetic, suppressing the passage of magnetic flux between the distant magnetic portion 34 and the permanent magnet 33. In this configuration as well, as in the first embodiment, the path of the magnetic flux in the mover 30 is optimized, suppressing the generation of unnecessary magnetic flux that leads to increased ripple.

Therefore, as shown in FIG. 5 for the third embodiment "A3," it is possible to sufficiently suppress the ripple rate, as in the first and second embodiments. This also leads to a greater degree of freedom in the combination of the number of magnetic poles of the stator 20 and the mover 30. Moreover, it is possible to maintain a high thrust force in the third embodiment "A3."

(Effects of this embodiment)
The effects of this embodiment will be described.
(3-1) In this embodiment as well, it is possible to obtain the same advantages as the advantages (1-1) to (1-3) of the first embodiment.

(3-2) The entire inner parts 31a, 31b of the annular permanent magnet 33 and the magnetic part 34 are non-magnetic, so this embodiment also effectively suppresses unnecessary magnetic flux that crosses the shaft part 31. As with the first embodiment, it is possible to more reliably suppress ripples.

(Example of change)
The above-described embodiments may be modified as follows: The above-described embodiments and the following modifications may be combined with each other to the extent that no technical contradiction occurs.

- In the magnetic pole portion 32 of the mover 30, the part X1 having the permanent magnet 33 and the part X2 having the magnetic portion 34 are inserted into the cylindrical member 35 to be integrally configured, but the parts X1 and X2 may be fixed to each other using adhesive. In this case, the cylindrical member 35 may be omitted.

As shown in FIG. 10, the shaft 31 of the mover 30 may be made from a single long shaft material, and the annular permanent magnet 33 and the annular magnetic part 34 may be attached to the outer circumferential surface. This aspect is particularly applicable to the case where the permanent magnet 33 and the inner parts 31a, 31b of the magnetic part 34 constituting a part of the shaft 31 are both made of non-magnetic metal material, as in the mover 30 of the third embodiment shown in FIG. 8. The shaft 31 can be made from a single long shaft material such as a non-magnetic metal or non-magnetic resin. In this way, it is expected that the rigidity of the shaft 31 can be increased. Of course, as in the first and second embodiments shown in FIG. 2 and FIG. 6, even if the permanent magnet 33 and the inner parts 31a, 31b of the magnetic part 34 are made of different materials, a single long shaft 31 may be made in advance, and then the permanent magnet 33 and the magnetic part 34 may be attached.

- As shown in Figures 11 and 12, each permanent magnet 33a, 33b may be used in the mover 30. The permanent magnet 33 used in the mover 30 is composed of one polar anisotropic magnet, but as shown in Figure 11, a permanent magnet 33a consisting of two polar anisotropic magnets divided into two in the axial direction may be used. Also, as shown in Figure 12, a permanent magnet 33b consisting of a Halbach array magnet made of three magnetic materials divided into three in the axial direction may be used. Of course, each permanent magnet 33a, 33b has the same function as the permanent magnet 33 described above.

- As shown in FIG. 13, a permanent magnet 33c may be used in which both axial end faces are inclined so as to widen toward the stator 20. The permanent magnet 33c is, for example, a Halbach array magnet. The permanent magnet 33c with both axial end faces inclined is expected to have the effect of gradual change in the magnetic flux distribution in the axial direction.

- Although not shown, not only can the permanent magnets 33 used in the mover 30 be changed to the permanent magnets 33a to 33c, but the permanent magnets 24 used in the stator 20 can also be changed in the same way as the permanent magnets 33a to 33c.

- As shown in FIG. 14, slits 23a extending in the axial direction may be provided on the inner peripheral surface of the magnetic plate 23 of the stator 20, i.e., the surface facing the mover 30. Also, slits 34a extending in the axial direction may be provided on the outer peripheral surface of the magnetic part 34 of the mover 30, the surface facing the stator 20. Each slit 23a, 34a is provided, for example, in a plurality at equal intervals in the circumferential direction. The function of each slit 23a, 34a is the same, and effects such as magnetic flux straightening can be expected. Although not shown, similar effects can be expected by providing protruding stripes instead of each slit 23a, 34a.

As shown in FIGS. 15 to 18, a mode may be adopted in which long members 36 a and 36 b extending over the entire axial direction of a shaft portion 31 of a mover 30 are disposed within the shaft portion 31 .
In the embodiment shown in Figs. 15 and 16, the long member 36a is made of a non-magnetic material and also functions as a non-magnetic part. If the long member 36a is made of a metal material, it is possible to expect an effect such as increasing the rigidity of the shaft part 31 of the mover 30. Furthermore, if the long member 36a is made of a resin material, it is possible to expect an effect such as reducing the weight of the shaft part 31 of the mover 30. In the embodiment shown in Figs. 17 and 18, the long member 36b is made of a magnetic material. If the long member 36b is made of a metal material, it is possible to expect an effect such as increasing the rigidity of the shaft part 31 of the mover 30. Note that the embodiment shown in Figs. 15 and 17 is applied to the above-mentioned first embodiment in which the inner part 31a of the permanent magnet 33 is made of a non-magnetic material. Furthermore, the embodiment shown in Figs. 16 and 18 is applied to the above-mentioned second embodiment in which the inner part 31b of the magnetic part 34 is made of a non-magnetic material.

As shown in FIG. 19, a plurality of rod-shaped members 37a made of a non-magnetic material may be used as an example of the long member 36a. The rod-shaped members 37a are provided at equal intervals in the circumferential direction at the radial middle position of the shaft portion 31. As shown in FIG. 20, a cylindrical member 37b made of a non-magnetic material may be used as an example of the long member 36a. The inner portion 37c of the cylindrical member 37b may be made of a magnetic material or may be made of an air gap. As shown in FIG. 21, both the cylindrical member 37b and the inner portion 37c shown in FIG. 20 may be made of a non-magnetic material, i.e., a cylindrical member 37d. The cylindrical member 37d is provided at the center of the shaft portion 31.

- At least a portion of the shaft portion 31 of the mover 30 is made of a non-magnetic metal material, but the non-magnetic portion may be formed by changing to a non-magnetic resin material. The non-magnetic portion may also be formed by making a magnetic material into a non-magnetic material through post-processing. The non-magnetic portion may also be formed by a gap, such as making a part or the entire shaft portion 31 of the mover 30 hollow.

The above combination of the number of magnetic poles of the stator 20, which is the armature, and the number of magnetic poles of the mover 30, which is the field element, is one example and may be changed as appropriate. If the number of pole pairs of the armature is "m" and the number of pole pairs of the field element is "n", it is sufficient that the configuration satisfies "n = m ± 1", which is a vernier motor.

The radial relationship between the stator 20 and the mover 30 may be reversed, such as with the stator 20 on the radial inside and the mover 30 on the radial outside.
Although the stator 20 is configured as an armature and the mover 30 is configured as a field element, the stator 20 may be configured as a field element and the mover 30 as an armature.

- The term "at least one" as used in this disclosure means "one or more" of the desired options. As an example, the term "at least one" as used in this disclosure means "only one option" or "both of the two options" if there are two options.

M1-M3 vernier motor, L1 shaft, 20 stator (armature), 21 magnetic pole part (first magnetic pole part), 22 coil, 23 magnetic plate (magnetic member), 30 mover (field magnet), 31 shaft part (rear side part), 31a, 31b inner part (rear side part), 32 magnetic pole part (second magnetic pole part), 33, 33a-33c permanent magnet, 34 magnetic part

Claims (13)

an armature (20) including a plurality of first magnetic pole portions (21) of a pole pair, each of which includes a coil (22) and a magnetic member (23), arranged in a straight line;
a field element (30) including a plurality of second magnetic pole portions (32) of a pole pair, each of which includes a permanent magnet (33, 33a to 33c) and a magnetic portion (34), arranged in a straight line;
A linear vernier motor (M1 to M3) configured to obtain a magnetic deceleration effect during magnetic transmission between the first and second magnetic pole portions based on current flow through the coil, and to obtain a linear thrust force in an axial (L1) direction by a relative linear motion of the armature and the field element,
The field element is composed of a polar anisotropic magnet or a Halbach array magnet that allows magnetic flux to pass between the permanent magnet and the adjacent magnetic portion, and at least a part of a first back side portion (31a) located on the back side of the permanent magnet with respect to the armature and a second back side portion (31b) located on the back side of the magnetic portion with respect to the armature are composed of a non-magnetic portion ,
The first rear side portion (31a) and the second rear side portion (31b) are separate members .
Vernier motor. The armature is configured as a stator (20) having a circular ring shape,
The field element is configured as a mover (30) arranged radially inside the stator.
2. The vernier motor according to claim 1. The field element is integrally configured including a portion where a first part (X1) including the permanent magnet and a second part (X2) including the magnetic portion are stacked in the axial direction.
3. The vernier motor according to claim 2. The first and second parts are housed in a tubular member (35).
4. The vernier motor according to claim 3. The field element is configured such that the permanent magnet and the magnetic portion each have an annular shape, and the permanent magnet and the magnetic portion are attached to a long shaft portion (31).
3. The vernier motor according to claim 2. The field element has a ring-shaped permanent magnet, and an inner portion (31a) of the permanent magnet is configured as the non-magnetic portion.
3. The vernier motor according to claim 2. The field element has a magnetic portion having an annular shape, and an inner portion (31b) of the magnetic portion is configured as the non-magnetic portion.
3. The vernier motor according to claim 2. In the field element, the permanent magnet and the magnetic portion each have an annular shape, and inner portions (31a, 31b) of the permanent magnet and the magnetic portion are both configured as the non-magnetic portion.
3. The vernier motor according to claim 2. The field element has a shaft portion (31a) extending in the axial direction, and a long member (36a, 36b) extending entirely in the axial direction is disposed in the shaft portion.
3. The vernier motor according to claim 2. The elongated member is made of a non-magnetic material.
10. The vernier motor according to claim 9. The elongated member is made of a magnetic material.
10. The vernier motor according to claim 9. The field element is configured to have a slit (34a) or a protrusion extending in the axial direction on a surface of the magnetic portion facing the armature.
3. The vernier motor according to claim 2. The armature is configured to have a slit (23a) or a protrusion extending in the axial direction on a surface of the magnetic member facing the field element.
3. The vernier motor according to claim 2.