TWI521833B - Linear motor - Google Patents

Description

Linear motor

The present invention relates to a linear motor.

A linear motor is used to convert electrical energy into linear motion. Depending on the use of the linear motor, it is desirable to minimize the leakage magnetic field. Japanese Laid-Open Patent Publication No. 2006-304438 discloses a technique for reducing a leakage magnetic field by arranging a magnetic plate at an end portion of a yoke of a stator.

Fig. 1 is a structural view showing a stator of a conventional linear motor. In the conventional linear motor, the stator 20r includes a pair of yokes (back yokes) 22a and 22b that are disposed to face each other, and a plurality of inner side faces S1 of the back yokes 22a and 22b are disposed in a movable direction of the rotor (not shown). Field magnets 24. Further, the magnetic plate 30r is provided so as to be in contact with the end side surface S2 of each of the back yokes 22a and 22b.

The magnetic permeability of the magnetic plate 30r is greater than the magnetic permeability of the air. From the characteristics of the magnetic flux, it travels in a path having a large magnetic permeability. Therefore, and not When the magnetic plate 30r is present, a relatively large amount of magnetic flux passes through the space occupied by the magnetic plate by mounting the U-shaped magnetic plate 30r on the side surface of the pair of back yokes. That is, the magnetic flux can converge in the space and relatively inhibit the magnetic flux from diverging to other spaces.

However, the inventors of the present invention have studied the linear motor having the stator 20r of Fig. 1 and have understood the following problems.

In the stator 20r of Fig. 1, in order to reduce the leakage magnetic field, it is necessary to assemble the magnetic resistance between the back yoke 22 and the magnetic plate 30r so as not to be discontinuous. However, in reality, the magnetic resistance between the back yoke 22 and the magnetic plate 30r becomes discontinuous due to the gap 31 existing between the back yoke 22 and the magnetic plate 30r.

For example, the gap 31 is a gap created by (i) machining precision and assembly error (error caused by dimensional tolerance and geometric tolerance) of the back yoke 22 and the magnetic plate 30r. The magnetic resistance of the air is larger than the magnetic resistance of the back yoke 22 and the magnetic plate 30r which are themselves magnetic bodies.

Or the gap 31 is (ii) a surface treatment layer applied to the surfaces of the back yoke 22 and the magnetic plate 30r. The back yoke 22 and the magnetic plate 30r are magnetic bodies, that is, iron. Therefore, in order to prevent rust, a non-magnetic coating layer may be applied. The magnetic resistance of the non-magnetic surface treatment layer is larger than the magnetic resistance of the back yoke 22 and the magnetic plate 30r.

As above, there is a gap 31 having a large magnetic resistance between the back yoke 22 and the magnetic plate 30r, as shown by the arrow in FIG. 1, As shown in Fig. 2, the magnetic flux leaking from the back yoke 22 leaks to the outside without being completely absorbed by the magnetic plate 30r.

The present invention has been made in view of the related problems, and one of the exemplary purposes of one aspect is to provide a linear motor that reduces leakage magnetic fields.

1. The same state of the invention relates to a linear motor. The linear motor is a linear motor having a rotor that can move in the first direction and a stator. One of the rotor and the stator is provided with: a pair of back yokes oppositely disposed to sandwich the other of the stator and the rotor from a second direction perpendicular to the first direction; a plurality of field magnets, in a pair of back yokes The inner side faces are disposed in the first direction; the magnetic members are magnetically coupled between the respective ends of the pair of back yokes; and at least one auxiliary magnet is disposed inside or in contact with the magnetic member.

According to this aspect, even if a gap is formed between the magnetic member and the back yoke, the magnetic flux can be introduced into the magnetic member by the auxiliary magnet and returned to the yoke, so that the leakage magnetic field can be reduced.

The auxiliary magnet generates magnetic flux in a direction in which the flow of the target magnetic flux to be formed by the plurality of field magnets and the magnetic member is generated.

One of the at least one auxiliary magnets may be disposed to be in contact with both end side faces of one of the pair of back yokes and the field magnets disposed at the most end portions of one of the back yokes. The other of the at least one auxiliary magnet may be disposed to be in contact with both end side faces of the other of the pair of back yokes and the field magnets of the most end portions provided along the other of the back yokes .

Thereby, the magnetic flux can be introduced to the magnetic member more reliably. Further, the repulsive force of the auxiliary magnet and the field magnet at the most end portion can be reduced.

The magnetic member includes: a first portion that is parallel to the first direction and that is in contact with an end surface of one of the pair of back yokes; is parallel to the first direction, and is the other of the pair of back yokes a second portion that is in contact with the side of the end portion; and a third portion that is parallel to the second direction and that combines the first portion and the second portion, and the first and second directions with respect to the magnetic member The cross-sectional view when viewed in the third vertical direction may have a substantially U-shape.

At least one auxiliary magnet may be embedded inside the magnetic member.

One of the at least one auxiliary magnets may be disposed in the direction in which the magnetic flux is generated in the first direction in the first portion or the second portion.

One of the at least one auxiliary magnets may be disposed inside the third portion in a direction in which the magnetic flux is generated in the second direction.

One of the at least one auxiliary magnets may be disposed inside the corner of the magnetic member in a direction in which the magnetic flux is generated in an oblique direction.

2. Another aspect of the invention is also directed to a linear motor. The linear motor has a rotor that is movable in the first direction, and a stator. One of the rotor and the stator is provided with: a pair of back yokes oppositely disposed to sandwich the other of the stator and the rotor from a second direction perpendicular to the first direction; a plurality of field magnets, in a pair of back yokes The inner side faces are disposed along the first direction; and the magnetic member is magnetically coupled between the adjacent ends of the pair of back yokes. The magnetic member is configured to cover a portion of each of the end faces and the outer side faces of the pair of back yokes that are perpendicular to at least the first direction.

According to this aspect, even if a gap is formed between the magnetic body member and the end side surface of the back yoke, the gap can be covered by the magnetic member. Therefore, it is possible to introduce the magnetic flux leaking from the gap into the magnetic member and return to the magnetic The yoke is therefore able to reduce the leakage magnetic field.

The magnetic member may have a first portion and a second portion. Regarding the first portion, one of the second side faces perpendicular to the first side face and one of the pair of back yokes may be joined to the end faces of the pair of back yokes at both ends of the first side face. The outer side faces are substantially on the same plane, and the third side face opposite to the second side face is substantially flush with the outer side face of the other of the pair of back yokes. The second portion may have a concave portion covering the second side surface of the first portion, the third side surface, the fourth side surface parallel to the first side surface, and the end portion of the outer side surface of each of the pair of back yokes.

A groove is provided at an end portion of each of the pair of back yokes on the outer side surface, and the magnetic member can be formed to be fitted into the groove.

The corners of the magnetic member may be rounded.

The first part and the second part can be integrally formed. The first part and the second part can also be formed separately.

Furthermore, any combination of the above-described constituent elements, and the constituent elements and expressions of the present invention, which are mutually interchangeable between methods, devices, systems, etc., can also be considered as aspects of the present invention.

According to the invention, the leakage magnetic field can be reduced.

2‧‧‧Linear motor

10‧‧‧Rotor

20‧‧‧ Stator

22‧‧‧Y yoke

23‧‧‧ End

24‧‧ field magnet

24a‧‧‧ main pole

24b‧‧‧ pole

25‧‧‧ slots

26‧‧‧Auxiliary magnet

30‧‧‧Magnetic components

40‧‧‧ Stator

50‧‧‧Magnetic components

52‧‧‧Part 1

54‧‧‧Part 2

60‧‧‧ Stator

70‧‧‧ Magnetic components

72‧‧‧Part 1

74‧‧‧Part 2

76‧‧‧ Space

80‧‧‧ Stator

90‧‧‧Magnetic components

92‧‧‧Part 1

94‧‧‧Part 2

S1‧‧‧ inside side

S2‧‧‧ end side

S3‧‧‧ outside side

S11‧‧‧ first side

S12‧‧‧2nd side

S13‧‧‧3rd side

S14‧‧‧4th side

Fig. 1 is a structural view showing a stator of a conventional linear motor.

Fig. 2 (a) and (b) show the linear motor of the first embodiment. Picture.

Fig. 3 is a view showing the principle of the linear motor of the first embodiment.

Fig. 4 (a) to (c) are plan views showing a modified example of the stator.

Fig. 5 (a) and (b) are plan views showing a modification of the stator.

Fig. 6 (a) to (h) are plan views showing a modified example of the stator.

Fig. 7 is a plan view showing the stator of the second embodiment.

Fig. 8 is a view showing a magnetic field pattern in the stator of Fig. 7.

Fig. 9 (a) to (c) are plan views showing a modified example of the stator.

Fig. 10 is a plan view showing the stator of the third embodiment.

Hereinafter, the present invention will be described as a preferred embodiment with reference to the accompanying drawings. In the same or equivalent constituent elements, members, and processes in the drawings, the same reference numerals will be given, and the overlapping description will be appropriately omitted. The embodiments are not intended to limit the invention, and all the features and combinations described in the embodiments do not limit the essentials of the invention.

(First embodiment)

Fig. 2 (a) and (b) are views showing a linear motor according to the first embodiment. Fig. 2(a) is a perspective view of the linear motor 2, and Fig. 2(b) is a plan view showing the stator 20. In Fig. 2(b), only one end side of the stator 20 is shown, and the other end is also configured identically.

The linear motor 2 includes a rotor 10 that is movable in the first direction (X direction) and a stator 20 . The rotor 10 has an armature winding (not shown) (line ring). This embodiment can also be applied to any of a coreless linear motor or a magnetic core linear motor, and the structure of the rotor 10 is not particularly limited.

The stator 20 includes a yoke 22, a plurality of field magnets 24, at least one (two in the present embodiment) auxiliary magnets 26a and 26b, and a magnetic member 30.

The yoke 22 has a pair of back yokes 22a and 22b that are opposed to each other so as to sandwich the rotor 10 from a second direction (Y direction) perpendicular to the first direction (X direction). The pair of back yokes 22a and 22b are integrally formed with the yoke 22c at the bottom.

A plurality of field magnets 24 disposed along the first direction are provided on the inner side surface S1 of each of the pair of back yokes 22a and 22b. In the present embodiment, the plurality of field magnetic fields 24 form a Halbach array in which the main pole 24a and the interpole 24b are alternately arranged.

The magnetic member 30 is magnetically coupled between the respective end portions S2 of the pair of back yokes 22a and 22b.

The auxiliary magnets 26a and 26b are provided in contact with the magnetic member 30. Specifically, the auxiliary magnet 26a is provided in a region sandwiched between the magnetic member 30 and the yoke 22a, and the auxiliary magnet 26b is provided in a region sandwiched between the magnetic member 30 and the yoke 22b.

The magnetic flux is formed by the plurality of field magnets 24 and the magnetic member 30. Figure 2 (b) by The target magnetic flux which should be formed by the plurality of field magnets 24 and the magnetic member 30 is shown. The auxiliary magnets 26a, 26b are arranged to be along the target magnetic flux Magnetic flux in the direction of flow , .

In the present embodiment, the auxiliary magnet 26a is provided in the vicinity of the end side surface S2a perpendicular to the first direction (X direction) of the back yoke 22a, and generates magnetic flux in the direction perpendicular to the end side surface S2a. . Similarly, the auxiliary magnet 26b is provided in the vicinity of the end side surface S2b of the back yoke 22b, and generates a magnetic flux in the direction perpendicular to the end side surface S2b. .

In the present embodiment, the magnetic member 30 is provided to surround the auxiliary magnets 26a and 26b. Specifically, the magnetic member 30 has a U shape, and the inner corners thereof are provided with auxiliary magnets 26a and 26b.

The auxiliary magnet 26a is preferably disposed so as to be in contact with both the end side surface S2a of the corresponding back yoke 22a and the field magnet 24a' at the end. Similarly, the auxiliary magnet 26b is disposed in contact with both the end side surface S2b of the back yoke 22b and the corresponding field magnet 24a' at the extreme end.

The above is the configuration of the linear motor 2.

Fig. 3 (a) and (b) are views showing the principle of the linear motor of the first embodiment. The mode in Fig. 3(a) shows the flow of the magnetic flux when the auxiliary magnet 26 is not present, and the mode in Fig. 3(b) shows the flow of the magnetic flux when the auxiliary magnet 26 is provided. In Figure 3 (a), The ideal flow (target direction) of the magnetic flux that should be formed by the field magnet 24 is shown. When the auxiliary magnet 26 is not present, as shown in Fig. 3(a), the actually formed magnetic flux deviates from the target direction. .

On the other hand, as shown in FIG. 3(b), when the auxiliary magnet 26 is provided, the auxiliary magnet 26 becomes a convergence point of the magnetic flux, and in FIG. 3(a), from the target direction. The magnetic flux (leakage magnetic field) in the direction of the disengagement is toward the target direction be introduced.

According to the linear motor 2, even if a gap is formed between the magnetic member 30 and the end side surface S2 of the yoke 22, the auxiliary magnets 26a and 26b become a convergence point of the magnetic flux, so that the magnetic flux to be leaked to the outside by the gap can be introduced to The magnetic member 30 can reduce the leakage magnetic field.

In the linear motor 2r of Fig. 1, when there is a leakage magnetic field of the order of mT (mtests), if the structure of the linear motor 2 of the embodiment is used, the leakage magnetic field can be reduced to μ T (micro Tesla). Magnitude.

Next, a modification of the linear motor 2 of the first embodiment will be described.

(Modification 1.1)

4(a) to 4(c) are plan views showing a modification of the stator 20. In the modification of Figs. 4(a) to 4(c), the shape of the magnetic member 30 is different from the shape of Fig. 2 . In the stator 20a of Fig. 4(a), the magnetic member 30a is also present in a region (a cross-sectional line drawn) sandwiched between the auxiliary magnets 26a and 26b. In other words, a rectangular parallelepiped is formed in a state in which the auxiliary magnets 26a and 26b are fitted into the magnetic member 30a.

In the stator 20b of Fig. 4(b), the magnetic member 30b is formed by rounding the corners of the magnetic member 30 of Fig. 2(b). The magnetic member 30c of the stator 20c of Fig. 4(b) is a combination of the modifications of Figs. 4(a) and 4(b).

Also in these modifications, the same effects as those of the linear motor 2 of Figs. 2(a) and 2(b) can be obtained.

(Modification 1.2)

Fig. 5 (a) and (b) are plan views showing a modification of the stator 20. In the stator 20e of Fig. 5(a), the main pole 24a and the interpole 24b are arranged opposite to the second figure (b). Specifically, the field magnet 24 at the extreme end becomes the interpole 24b. The orientation of the auxiliary magnets 26a and 26b is at right angles to the orientation of the auxiliary magnets 26a and 26b of Fig. 2(a). In the stator 20f of Fig. 5(b), only the field magnets 24 corresponding to the main poles are arranged at intervals.

Also in these modifications, the same effects as those of the linear motor 2 of Figs. 2(a) and 2(b) can be obtained. Further, the combination of the modification 1 and the modification 2 is also effective.

(Modification 1.3)

Although the case where the two auxiliary magnets 26 are provided has been described so far, the present invention is not limited thereto, and the auxiliary magnets 26 may be provided at least one. Fig. 6 (a) to (h) are plan views showing a modification of the stator 20. As shown in these modifications, the auxiliary magnets 26 may be any number of one, two, or three, and the auxiliary magnets 26 may be embedded in the magnetic member 30. In these variations, the auxiliary magnets 26 are configured to be respectively along the target magnetic flux Magnetic flux in the direction . The following technical idea is derived from the modification of Fig. 6 (a) to (g).

The magnetic member 30 includes a first portion that is parallel to the first direction (the horizontal direction on the paper surface) and that is in contact with the end surface of one of the pair of back yokes, and is parallel to the first direction, and 1 pair of back yokes in another The second portion of the end portion of the 22b is joined to the second portion; and the second portion (the vertical direction on the paper surface) is parallel, and the third portion of the first portion and the second portion are combined. The magnetic member 30 has a substantially U-shaped cross-sectional view when viewed in a third direction (vertical direction from the paper surface) perpendicular to the first direction and the second direction. At least one auxiliary magnet 26 is embedded in the inside of the magnetic member 30.

As shown in FIGS. 6(b), (c), (e), and (f), at least one of the auxiliary magnets generates a magnetic flux in the first direction in the first portion or the second portion. Heading configuration.

As shown in Fig. 6 (a), (f), and (g), at least one of the auxiliary magnets is disposed inside the third portion in a direction in which the magnetic flux is generated in the second direction.

As shown in Fig. 6(d), at least one of the auxiliary magnets is disposed inside the corner of the magnetic member 30 in such a direction as to generate a magnetic flux in an oblique direction.

(Modification 1.4)

In the embodiment, the coil movable type in which the coil is provided on the rotor side has been described. However, the present invention is also applicable to a coil-fixed type linear motor in which the coil is provided on the stator side. At this time, the back yokes 22a and 22b, the field magnet 24, the auxiliary magnet 26, and the magnetic member 30 form a rotor.

(Second embodiment)

Fig. 7 is a plan view showing the stator 40 of the second embodiment. set The sub-40 includes a yoke 22, a plurality of field magnets 24, and a magnetic member 50.

The structure of the yoke 22 and the field magnet 24 are the same as in the first embodiment.

The magnetic member 50 is magnetically coupled between the end portions of the pair of back yokes 22a and 22b adjacent to each other. The magnetic member 50 is configured to cover the end portions 23 of at least the end side surface S2 and the outer side surface S3 of the respective side faces of the pair of back yokes 22a and 22b.

The magnetic member 50 of FIG. 7 includes a first portion 52 and a second portion 54. The first portion 52 is a rectangular parallelepiped block having a first side surface S11 and a fourth side surface S14 opposed thereto, and a second side surface S12 and a third side surface S13 opposed thereto. The first portion 52 is in contact with the end side surface S2 of each of the pair of back yokes 22a and 22b at both ends of the first side surface S11. Further, in the first portion 52, the second side surface S12 and the outer side surface S3 of one of the pair of back yokes 22 are substantially in the same plane, and the third side surface S13 and the other one of the pair of back yokes 22b The outer side faces S3 are substantially on the same plane.

The second portion 54 has a U shape and has an end portion 23 covering the second side surface S12, the third side surface S13, and the fourth side surface S14 of the first portion 52, and the outer side surfaces of the pair of back yokes 22a and 22b. The recess.

The above is the configuration of the stator 40.

Fig. 8 is a view showing a magnetic field pattern in the stator 40 of Fig. 7. The magnetic field is indicated by a dashed line. According to the stator 40, even if a gap 51 is formed between the end side surface S2 of the back yokes 22a and 22b and the first side surface S11 of the first portion 52, the gap 51 is still the second portion of the magnetic member 50 from 54. Outside cover. Therefore, even if magnetic flux leakage from the gap 51 to the outside occurs, It is also introduced into the second portion 54 by the second portion 54 of the magnetic member 50, thereby returning directly to the yoke 22. Thereby, the leakage magnetic field when the yoke 22 is seen as one body can be reduced.

Next, a modification of the linear motor of the second embodiment will be described.

(Modification 2.1)

Fig. 9 (a) to (c) are plan views showing a modification of the stator 40. In the magnetic member 50a of Fig. 9(a), the first portion 52 and the second portion 54 of Fig. 7 are formed as an integral part. The ends of the end side surface S2 and the outer side surface S3 of the back yokes 22a and 22b are covered by the magnetic member 50a.

In Fig. 9(b), the end portions 23 of the outer side faces S3 of the back yokes 22a and 22b are formed with grooves 25a and 25b. The magnetic member 50b is formed to be engageable with the grooves 25a and 25b. Specifically, the second side surface S12 and the third side surface S13 of the first portion 52b are substantially flush with the bottom surfaces of the grooves 25a and 25b. The second portion 54b has a bottom surface with the groove 25a, a second side surface S12 of the first portion 52b, a fourth side surface S14 of the first portion 52b, a third side surface S13 of the first portion 52b, and a bottom surface of the groove 25b. Concave the concavity.

By providing the grooves 25a and 25b, the outer side faces S3 of the back yokes 22a and 22b and the side faces of the magnetic member 50b can be aligned on the same plane.

In the stator 40c of Fig. 9(c), the magnetic member 50c is formed such that the first portion 52 and the second portion 54 of Fig. 9(b) are inseparable. Cut the whole.

In the stator 40 of the second embodiment and its modifications, a modification described in the first embodiment can be applied. That is, the arrangement of the field magnets 24 can be changed, and the corners of the magnetic member can be rounded.

(Third embodiment)

The stator 40 of the third embodiment is a combination of the first embodiment and the second embodiment.

Fig. 10 is a plan view showing the stator 80 of the third embodiment. The stator 80 includes a pair of back yokes 22a and 22b, a plurality of field magnets 24, a pair of auxiliary magnets 26a and 26b, and a magnetic member 90.

The magnetic member 90 is configured to cover the exposed portion of the side faces of the back yokes 22a and 22b which are not covered by the auxiliary magnets 26a and 26b of the end side surface S2 and the end portion 23 of the outer side surface S3.

Specifically, the magnetic member 90 includes a first portion 92 and a second portion 94. The first portion 92 corresponds to the magnetic member 30 (Figs. 2(a) and 2(b)) of the first embodiment, and the second portion 54 and the second portion 54 of the magnetic member 50 of the second embodiment. (Fig. 7) Correspondence.

The first portion 92 is in contact with the end side surface S2 of each of the pair of back yokes 22a and 22b in the first side surface S11, and the second side surface S12 and the outer side surface S3 of one of the back yokes are substantially On the same plane, the third side S13 is substantially in the same plane as the outer side S3 of the other of the back yokes 22b.

The second portion 94 has a second side S12 covering the first portion 92, The third side surface S13 and the fourth side surface S14 and the concave portion of the end portion 23 of the outer side surface S3 of each of the pair of back yokes 22a and 22b.

According to the third embodiment, the leakage magnetic field can be reduced by the auxiliary magnet 26, and the leakage magnetic field can be reduced by the second portion 94.

It is needless to say that the stator 80 of the third embodiment can be modified as described in the first and second embodiments, and these are also included in the aspect of the invention. Hereinafter, these modifications will be described.

(Modification 3.1)

The first portion 92 may also have a magnetic member in a region (a cross-sectional line drawn) of the auxiliary magnets 26a and 26b sandwiched between the upper cross-sectional lines shown in Fig. 4(a).

Further, as shown in Fig. 4 (a) and (b), the corner of the magnetic member 90 (second portion 94) can be rounded.

(Modification 3.2)

Further, as shown in Fig. 5 (a) and (b), the arrangement of the field magnets 24 can be changed.

(Modification 3.3)

Further, similarly to the modification of Fig. 9(a), the first portion 92 and the second portion 94 may be formed as an integral part.

Similarly to the modification of Fig. 9(b), the groove 25 may be provided at the end portion 23 of the outer side surface S3 of the pair of back yokes 22a and 22b, and magnetic The body member 90 (the second portion 94) is fitted. In this case, the first portion 92 and the second portion 94 may be formed as an integral part.

(Modification 3.4)

The number of the auxiliary magnets 26 is not particularly limited. Further, as shown in FIGS. 6(a) to (h), the auxiliary magnet 26 can be fitted inside the first portion 92 corresponding to the magnetic member 30.

The present invention has been described above based on the embodiments. It will be understood by those skilled in the art that the embodiment is exemplified, and various modifications can be made to the combination of these components and the respective processing steps, and such modifications are also within the scope of the invention.

The various linear motors described above can be utilized in a variety of applications where leakage magnetic fields are required to be reduced. As such a use, a driver used in a scanning electron microscope (SEM) can be exemplified. In SEM, the leakage magnetic field bends the electron orbit and therefore has a great influence on the accuracy of the measurement. Since the linear motor has a very small leakage magnetic field, it is suitable for use in a driver such as a driver inside the SEM, for example, position control of a stage, position control of a beam source, or the like.

The present invention has been described with reference to specific embodiments. However, the embodiments are merely illustrative of the principles and applications of the present invention. In the embodiments, many variations are accepted without departing from the scope of the invention as defined in the appended claims. Examples and configuration changes.

[Industrial availability]

The present invention relates to a linear motor.

2‧‧‧Linear motor

10‧‧‧Rotor

20‧‧‧ Stator

S1‧‧‧ inside side

S2‧‧‧ end side

22a‧‧ yoke

22b‧‧ yoke

22c‧‧ yoke

24a‧‧‧ main pole

24a’‧‧ field magnet

24b‧‧‧ pole

26a‧‧‧Auxiliary magnet

26b‧‧‧Auxiliary magnet

30‧‧‧Magnetic components

Claims (14)

A linear motor having a rotor movable in a first direction and a stator, wherein one of the stator and the rotor includes: a pair of back yokes sandwiched by a second direction perpendicular to the first direction Holding the other of the stator and the rotor; the plurality of field magnets are disposed along the first direction on the inner side surface of each of the pair of back yokes; and the magnetic member is magnetically coupled to the pair of back yokes Between the respective ends; and at least one auxiliary magnet, respectively disposed inside the magnetic member or in contact with the magnetic member; the auxiliary magnet is configured to be along the plurality of A magnetic flux is generated in the direction in which the field magnet and the magnetic body member form a flow of the target magnetic flux. The linear motor of claim 1, wherein one of the at least one auxiliary magnet is disposed to be adjacent to an end side of one of the pair of back yokes and along one of the back yokes Two of the at least one auxiliary magnets are disposed in contact with each other, and the other of the at least one auxiliary magnet is disposed to be adjacent to the end side of the other of the pair of back yokes and along the back yoke The other of the field magnets at the other end of the other end are in contact with each other. A linear motor as claimed in claim 1 or 2, wherein The magnetic member includes a first portion that is parallel to the first direction and that is in contact with an end surface of one of the pair of back yokes, and is parallel to the first direction and is opposite to the first pair of magnetisms a second portion of the other end of the yoke that meets the second side; and a second portion that is parallel to the second direction and that combines the first portion with the third portion of the second portion, and from the first The cross-sectional view when viewed in the third direction perpendicular to the second direction is substantially U-shaped, and the at least one auxiliary magnet is embedded in the inside of the magnetic member. The linear motor according to claim 3, wherein one of the at least one auxiliary magnets is disposed in a direction in which the magnetic flux is generated in the first direction in the first portion or the second portion. . The linear motor according to claim 3, wherein one of the at least one auxiliary magnets is disposed inside the third portion in a direction in which a magnetic flux is generated in the second direction. The linear motor according to claim 3, wherein one of the at least one auxiliary magnets is disposed inside the corner of the magnetic member in a direction in which a magnetic flux is generated in an oblique direction. A linear motor having a rotor movable in a first direction and a stator, wherein the stator includes: a pair of back yokes that are opposed to each other in a second direction perpendicular to the first direction Setting a plurality of field magnets are disposed along the first direction on the inner side surface of each of the pair of back yokes; and the magnetic member is magnetically coupled between the adjacent end portions of the pair of back yokes, and is configured to cover the foregoing A portion of each of the pair of back yokes that is perpendicular to the first direction and the side of the outer side. The linear motor according to claim 7, wherein the magnetic member covers 1/2 or more of a field magnet width of an end portion of an outermost side surface of the back yoke. The linear motor according to claim 7 or 8, wherein the magnetic member has a first portion, and the end portion of each of the pair of back yokes at both ends of the first side surface The second side surface perpendicular to the first side surface and the outer side surface of one of the pair of yokes are substantially in the same plane, and the third side surface opposite to the second side surface and the pair of back yokes The outer side surface of the other of the other ones is substantially on the same plane; and the second portion has a fourth side surface that is parallel to the first side surface covering the first portion, and a pair of the pair of back yokes a recess of the end of the outer side. The linear motor according to claim 7, wherein the outer side surface of each of the pair of back yokes is provided with a groove, and the magnetic member is formed to be engageable in the groove. The linear motor according to claim 7, wherein the corner of the magnetic member is rounded. The linear motor of claim 9, wherein the first portion is integrally formed with the second portion. The linear motor according to claim 9, wherein the first portion and the second portion are formed separately. The linear motor according to claim 7, further comprising at least one auxiliary magnet provided inside the magnetic member or in contact with the magnetic member.