WO2023188430A1

WO2023188430A1 - Galvanometer scanner

Info

Publication number: WO2023188430A1
Application number: PCT/JP2022/016998
Authority: WO
Inventors: 剛森; 悌史 ▲高▼橋
Original assignee: 三菱電機株式会社
Priority date: 2022-04-01
Filing date: 2022-04-01
Publication date: 2023-10-05

Abstract

A galvanometer scanner (1) is provided with: a rotor (7) having a permanent magnet (6) in which circumferentially differing magnetic poles are formed alternately, and a rotational shaft (4) disposed on both sides axially with respect to the permanent magnet (6); a stator (13) having a stator core (12), and a plurality of coils (9) that are disposed on the inner-diameter side of the stator core (12) and on the outer-diameter side of the rotor (7) with a gap (20) therebetween, and that have a central hole (9a) which is a space; and a galvanometer mirror (14) coupled to the rotational shaft (4) of the rotor (7). The stator (13) is provided with a detouring path (8), which is a magnetic component disposed: in a location corresponding to at least one axial end of the permanent magnet (6); on the inner side of the plurality of coils (9); and on the inner-diameter side of the stator core (12).

Description

galvano scanner

The present disclosure relates to a galvano scanner that rotates an optical member.

A galvano scanner has a stator equipped with a coil, a rotor equipped with a permanent magnet, and an optical member that is a mirror attached to the rotation axis of the rotor. When performing continuous hole machining with a laser processing machine that uses a galvano scanner, the rotor of the galvano scanner repeats acceleration, deceleration, and stopping operations. When the rotor operates at high speed, the frequency of the drive current increases. As a result, eddy currents flow through the permanent magnets of the rotor, causing eddy loss and increasing the temperature of the permanent magnets. When the temperature of a permanent magnet becomes too high, thermal demagnetization occurs. This deteriorates the properties of the permanent magnet and causes problems in the operation of the galvano scanner.

In Patent Document 1, a plurality of grooves extending from the outer diameter side to the inner diameter side are formed in the permanent magnet so as to block the path of eddy current, thereby suppressing the temperature rise of the permanent magnet due to eddy loss.

Japanese Patent Application Publication No. 2008-43133

In Patent Document 1, the plurality of grooves formed in the permanent magnet are formed at positions that obstruct the path of eddy current, so the temperature rise of the permanent magnet due to eddy loss is suppressed. However, because the magnets are connected near the shaft of the permanent magnet, the eddy current is not completely blocked and flows around the groove. Further, since the current magnetic flux that causes eddy loss passes through the groove, an eddy current loop occurs locally in the portion separated by the groove, resulting in eddy loss. For this reason, when the drive current is large and the frequency is high, there are problems such as the temperature of the permanent magnet rising beyond the limit and the rotation sensor exceeding the operating temperature range.

The present disclosure has been made in view of the above, and aims to provide a galvano scanner that can reduce the eddy loss generated in the permanent magnet and suppress the temperature rise of the permanent magnet.

In order to solve the above-mentioned problems and achieve the objective, a galvano scanner according to the present disclosure includes a permanent magnet in which different magnetic poles are alternately formed in the circumferential direction, and a rotating shaft arranged on both sides of the permanent magnet in the axial direction. A stator having a rotor, a stator core, and a plurality of coils disposed on the inner diameter side of the stator core and on the outer diameter side of the rotor through a gap, and having a center hole, which is a space, an optical member connected to the rotating shaft. The stator is characterized by comprising a first magnetic body disposed at a position corresponding to at least one end in the axial direction of the permanent magnet, inside the plurality of coils, and on the inner diameter side of the stator core. .

According to the galvano scanner of the present disclosure, it is possible to reduce the eddy loss generated in the permanent magnet and suppress the temperature rise of the permanent magnet.

A vertical cross-sectional view showing the configuration of a galvano scanner according to Embodiment 1. A top view showing the arrangement of coils, etc. of the galvano scanner according to Embodiment 1. A top view showing a coil of the galvano scanner according to Embodiment 1. 2 is a cross-sectional view showing essential parts of the galvano scanner according to Embodiment 1, and is a cross-sectional view taken along line IV-IV in FIG. 1. 2 is a cross-sectional view showing essential parts of the galvano scanner according to Embodiment 1, and is a cross-sectional view taken along line VV in FIG. 1. A cross-sectional perspective view showing the internal structure of a quarter portion of the galvano scanner according to the first embodiment. A cross-sectional perspective view showing the internal structure of a quarter portion of the galvano scanner according to Embodiment 1, with the rotor omitted. Cross-sectional view showing the main parts of a galvano scanner as a comparative example A cross-sectional perspective view showing the internal structure of a quarter portion of the galvano scanner according to the second embodiment. Vertical cross-sectional view in which a part of the galvano scanner according to Embodiment 4 is enlarged A cross-sectional perspective view showing the internal structure of a quarter portion of the stator of the galvano scanner according to Embodiment 5. A perspective view showing the overall configuration of a detour of a galvano scanner according to Embodiment 5. Top view showing the configuration of a galvano scanner according to Embodiment 6 Cross-sectional view showing main parts of a galvano scanner according to Embodiment 7 A cross-sectional perspective view showing the internal structure of a quarter portion of a stator of a galvano scanner according to Embodiment 8.

Below, a galvano scanner according to an embodiment will be described in detail based on the drawings.

Embodiment 1.
FIG. 1 is a longitudinal cross-sectional view showing the configuration of a galvano scanner according to the first embodiment. The vertical cross-sectional view is a cross-sectional view taken along a plane that includes the rotation axis of the galvano scanner. In FIG. 1, the galvano scanner 1 includes a rotor 7, a stator 13, a galvanometer mirror 14 as an optical member, and a rotation sensor 11.

The rotor 7 has a rotating shaft 4, a permanent magnet 6, and a detour 5 that is a second magnetic body. The rotating shaft 4 is rotatably supported by the housing 2 via a pair of bearings 3. The permanent magnet 6 has a cylindrical shape, is placed inside the rotating shaft 4, and is fixed to the rotating shaft 4 with an adhesive or the like. In the following description, the direction parallel to the axial direction of the rotating shaft 4 is defined as the X direction. The detour path 5 is arranged at both ends of the permanent magnet 6 in the X direction. The permanent magnet 6 has different magnetic poles alternately formed in the circumferential direction. The rotating shaft 4 is arranged on both sides of the permanent magnet 6 in the X direction.

The stator 13 is fixed to the housing 2 and placed on the outer diameter side of the rotor 7 with a gap 20 interposed therebetween. The stator 13 includes a plurality of coils 9, a stator core 12 that is a magnetic material, and a detour 8 that is a first magnetic material. The plurality of coils 9 are arranged on the outer diameter side of the rotor 7. The plurality of coils 9 have a hollow shape (doughnut shape), and have a center hole 9a in a hollow portion that is a space. The stator core 12 is arranged on the outer diameter side of the plurality of coils 9. The stator core 12 is formed in a cylindrical shape and includes a removed portion 10, which is a first space, on the outer diameter side of the center hole 9a of the coil 9. The removed portion 10 only needs to have at least a portion removed on the inner diameter side. In the first embodiment, the deleted portion 10 is a through hole. The detour 8 is arranged on the inner diameter side of the stator core 12 and inside the coil 9. The inside of the coil 9 refers to the inner diameter side of the hollow coil 9. Further, the detour 8 is disposed at a position in the X direction opposite to the detour 5 of the rotor 7 with the gap 20 interposed therebetween.

The stator core 12 is manufactured using, for example, a compacted iron core that is heat-treated after pressure-molding insulated permalloy powder. Note that the stator core 12 may be manufactured by punching out a plate material of a magnetic material such as an electromagnetic steel plate. The detour 5 disposed on the rotor 7 and the detour 8 disposed on the stator 13 are made of a magnetic material similarly to the stator core 12. Moreover, the stator core 12 only needs to have an inner circumferential surface formed of a cylindrical surface, and an outer circumferential surface thereof does not need to be a cylindrical surface.

The galvanometer mirror 14 is fixed to one end of the rotating shaft 4 in the axial direction. The galvanometer mirror 14 is an optical member connected to the rotor 7. The galvanometer mirror 14 is formed into a rectangular flat plate shape. The surface of the galvanometer mirror 14 serves as a reflective surface for the laser beam. The rotor 7 rotates within a predetermined angular range of about -4° to +4° mechanical angle. Therefore, the galvanometer mirror 14, which is an optical member connected to the rotor 7, rotates within a predetermined angular range of about -4° to +4° mechanical angle.

The rotation sensor 11 includes an encoder plate 22 and a sensor head 23. The encoder plate 22 is fixed to the other end of the rotating shaft 4 in the axial direction. The encoder plate 22 has a plurality of slits on its surface. The encoder plate 22 cooperates with the sensor head 23 to constitute a rotary encoder that feeds back the rotation angle of the galvanometer mirror 14 to a control circuit (not shown). Note that the rotary encoder may be any rotation angle detection device that detects the angular displacement of the galvanometer mirror 14 used for feedback control. Therefore, the rotation angle detection device is not limited to a rotary encoder, but may be a resolver.

FIG. 2 is a top view showing the arrangement of the coil 9, etc. of the galvano scanner 1 according to the first embodiment. FIG. 2 is a diagram showing essential parts of the galvano scanner 1 when viewed along arrow c in FIG. 1. As shown in FIG. In FIG. 2, the coil 9 and the detour 8 are indicated by broken lines in order to show the positional relationship between the stator core 12, the coil 9, and the detour 8. Further, illustration of the housing 2, rotor 7, bearing 3, galvanometer mirror 14, and encoder plate 22 is omitted. In the following figures, similar omissions are made unless otherwise stated.

As shown in FIG. 2, four rectangular coils 9 (the one on the back side is omitted in FIG. 2) each having a center hole 9a have a pair of parallel long sides of the rectangle parallel to the X direction. They are arranged circumferentially on the inner peripheral surface of the stator core 12. Coil 9 is fixed to stator core 12 with adhesive or mold. The coils 9 are arranged so that the removed portion 10 provided in the stator core 12 overlaps with the center hole 9a, and the long sides of the adjacent coils 9 are in contact with each other. Adjacent coils 9 are manufactured by winding in opposite directions. Therefore, the directions of currents flowing in the long sides of adjacent rectangular shapes of adjacent coils 9 are the same.

FIG. 3 is a top view showing the coil 9 of the galvano scanner 1 according to the first embodiment. As shown in FIG. 3, the coil 9 is made by winding a wire such as copper around a flat rectangular frame (not shown) the required number of times, and winding it in an arc shape along the inner peripheral surface of the stator core 12. It is made by bending and shaping.

In addition, in FIG. 2, the coils 9 are arranged in the circumferential direction with the long sides of the rectangles touching each other, but the coils 9 are arranged in the circumferential direction with the long sides of the adjacent rectangles separated by a predetermined gap. may be arranged in the direction.

FIG. 4 is a sectional view showing essential parts of the galvano scanner 1 according to the first embodiment, and is a sectional view taken along the line IV-IV in FIG. 1. FIG. 5 is a sectional view showing essential parts of the galvano scanner 1 according to the first embodiment, and is a sectional view taken along the line VV in FIG. 1. FIG. 6 is a cross-sectional perspective view showing the internal structure of a quarter portion of the galvano scanner 1 according to the first embodiment. In FIG. 6, for example, a quarter portion is extracted by cutting along line VI-VI in FIG. FIG. 7 is a cross-sectional perspective view showing the internal structure of a quarter portion of the galvano scanner 1 according to the first embodiment, with the rotor 7 omitted. In FIG. 7, the rotor 7 is removed from FIG. 6. 4 and 5, illustration of the housing 2 is omitted.

In FIG. 4, the outer peripheral surface of the permanent magnet 6 shows an N pole and an S pole, which are the polarities on the outer peripheral surface side of the magnetic poles of the permanent magnet 6. Different magnetic poles are alternately formed on the permanent magnet 6 along the circumferential direction, which is the rotational direction of the rotating shaft 4. The number of magnetic poles formed on the permanent magnet 6 is four. Further, the permanent magnet 6 is a polar anisotropic magnet magnetized into four poles, and is, for example, a magnet formed by sintering neodymium. Since the permanent magnet 6 is disposed inside the rotating shaft 4, the surface of the permanent magnet 6 is covered with the rotating shaft 4. The rotating shaft 4 is made of a non-magnetic material to prevent the magnet magnetic flux from short-circuiting. Here, SUS304 is used as the rotating shaft 4, but it is desirable to use a material with low electrical conductivity and little eddy current. For example, it may be a non-magnetic material such as ceramic.

In FIG. 4, the removed portion 10 of the stator core 12 is visible, and the center hole 9a of the coil 9 is also visible. In FIG. 5, the removed portion 10 of the stator core 12 is removed and a detour 8 is provided. The detour path 8 is arranged on both sides of the center hole 9a of the coil 9 in the X direction. It can also be said that the detour path 8 is arranged inside the coil 9 in the X direction. The detour 5 has a circular shape and is arranged inside the rotating shaft 4. The detour path 5 is arranged at both ends of the permanent magnet 6 in the X direction. The detour 8 and the detour 5 are arranged at opposing positions in the X direction.

In the galvano scanner 1 configured in this way, the number of poles of the permanent magnet 6 is four, and the number of coils 9 is four. When the number of poles of the permanent magnet 6 and the number of coils 9 are the same, as shown in FIG. This becomes the reference angle. The magnetic flux 24 of the permanent magnet 6 passes through the coil 9 from the N pole of the permanent magnet 6 and reaches the stator core 12, as shown by the dotted arrow in FIG. The magnetic flux passes through the coil 9 and enters the S poles on both sides of the N pole of the permanent magnet 6, forming two magnetic paths that pass through the permanent magnet 6 and return to the N pole. Moreover, as shown by the solid arrow in FIG. A current magnetic flux 25 flows in order through the surface of 4 and the detour 5.

Next, a laser processing operation using the galvano scanner 1 will be explained. The galvano mirror 14 of the galvano scanner 1 is placed in the path of a laser beam of a laser processing machine (not shown). Based on the output of the rotary encoder using the encoder plate 22, the rotation angle of the galvanometer mirror 14 is controlled by a control circuit (not shown). Since the direction of reflection of the laser beam changes depending on the rotation angle of the galvanometer mirror 14, the incident position of the laser beam onto the workpiece is controlled.

Before the laser processing operation, the rotation angle of the rotor 7 is adjusted. Specifically, the rotor 7 rotates to the reference angle. When a current is applied to the coil 9 in this state, the rotor 7 rotates in a direction according to Fleming's left-hand rule (clockwise in FIG. 4) due to interaction with the magnetic flux 24 of the permanent magnet 6. The rotation direction of the rotor 7 changes depending on the direction of the current flowing through the coil 9.

The current direction is controlled based on the rotation angle information from the rotary encoder, and the rotor 7 is accelerated and rotated. When the rotor 7 approaches the target stopping angle, the current direction is controlled in the opposite direction to decelerate the rotor 7, and the rotor 7 stops at the target stopping angle.

As described above, the rotor 7 repeats rotational operations in the order of acceleration, deceleration, stop, acceleration, and so on. For this reason, the galvano scanner 1 sequentially opens holes in the workpiece one by one while changing the irradiation position of the laser beam on the workpiece. Here, if the continuous drilling speed is 4000 points/sec, the current frequency is 4 kHz.

FIG. 8 is a sectional view showing the main parts of a galvano scanner of a comparative example. FIG. 8 is a sectional view corresponding to FIGS. 4 and 5 of the galvano scanner 101 of the comparative example. In the first embodiment, there are two types of cross-sectional structures perpendicular to the rotation axis 4, as shown in FIGS. 4 and 5, but in the galvano scanner 101 of the comparative example, there is only one type of cross-sectional structure perpendicular to the rotation axis. It is. The rotating shaft 104, permanent magnet 106, rotor 107, stator core 112, coil 109, magnet magnetic flux 124, and current magnetic flux 125 in FIG. 8 are the rotating shaft 4, rotor 7, permanent magnet 6, stator core 12, coil in FIGS. 9 corresponds to the magnet magnetic flux 24 and the current magnetic flux 25. By passing a current through the coil 109, the current magnetic flux 125 of the coil 109 reaches the inside of the permanent magnet 106. The magnetic field that reaches the interior of the permanent magnet 106 varies at 4kHz. Therefore, an eddy current flows through the permanent magnet 106, and the permanent magnet 106 generates heat due to Joule loss. That is, eddy loss occurs in the permanent magnet 6.

At this time, the stator core 112 is being cooled by a stator cooling device (not shown). Therefore, the temperature of stator core 112 is lower than that of rotor 107. Therefore, the heat of the permanent magnets 106 in the rotor 107 is radiated to the stator core 112. Further, the heat of the permanent magnet 106 is transmitted through the rotating shaft 104 and radiated in the axial direction. Therefore, the operating temperature range is reduced due to the occurrence of demagnetization due to the temperature rise of the permanent magnet 106, and the heat being transmitted to the rotation sensor corresponding to the rotation sensor 11 of the first embodiment via the rotation shaft 104, and the temperature of the rotation sensor increasing. deviation occurs.

Below, the effects of the galvano scanner 1 according to the first embodiment will be described. In the galvano scanner 1 according to the first embodiment, there are two types of cross sections of the coil 9 in the X direction position, as shown in FIGS. 4 and 5. The magnet magnetic flux 24 mainly flows through the path shown in FIG. 4, and the current magnetic flux 25 mainly flows through the path shown in FIG. The path of the magnet magnetic flux 24 is a closed loop path passing through the N pole of the permanent magnet 6, the surface of the rotating shaft 4, the coil 9, the stator core 12, the coil 9, the surface of the rotating shaft 4, and the S pole of the permanent magnet 6 in this order. The path of the current magnetic flux 25 is a closed loop path passing through the detour 5, the surface of the rotating shaft 4, the detour 8, the stator core 12, the detour 8, the surface of the rotating shaft 4, and the detour 5 in this order. The stator core 12 is common to these two routes. This means that in the stator core 12, since the magnetic flux flows avoiding the deleted portion 10, there are portions that follow the same path.

Here, inside the rotating shaft 4 of the rotor 7, the path passing through the permanent magnet 6 and the path passing through the detour 5 are parallel in terms of magnetic circuits. Furthermore, since the permanent magnet 6 has a larger magnetic resistance than the magnetic material of the stator core 12 and the magnetic materials of the

detours

5 and 8, the current magnetic flux 25 flowing through the detour 5 does not flow through the path that flows out to the permanent magnet 6. There are almost no Therefore, the current magnetic flux 25 hardly flows through the permanent magnet 6. Therefore, no eddy loss occurs and temperature rise is suppressed. On the other hand, although a current magnetic flux 25 flows through the detour path 5, when a dust core is used as the magnetic material, almost no eddy current flows and almost no eddy loss occurs.

Furthermore, in the first embodiment, the removed portion 10 is provided in the stator core 12 at the cross-sectional position shown in FIG. Considering the current magnetic flux 125 at this cross-sectional position as in the comparative example shown in FIG. It will be about the thickness. On the other hand, in the first embodiment, since the deleted portion 10 is also included in the magnetic gap, the magnetic gap between the rotor 7 and the stator core 12 is larger than the thickness of the coil 9 in the radial direction. Therefore, in the current magnetic flux path that passes through the permanent magnet 6, the magnetic resistance increases, making it difficult for the current magnetic flux 25 to flow. The current magnetic flux 25 will flow preferentially. As described above, the current magnetic flux 25 flowing through the permanent magnet 6 is reduced, and the eddy loss in the permanent magnet 6 can be reduced. As a result, demagnetization of the permanent magnet 6 and deviation of the operating temperature range of the rotation sensor 11 can be prevented.

As described above, according to the first embodiment, the rotor 7 is provided with the detour 5, and the stator 13 is provided with the detour 8 and the deletion portion 10. Therefore, the current magnetic flux flowing into the permanent magnet 6 is reduced, the eddy current generated due to the change in the current magnetic flux is reduced, and as a result, the eddy loss generated in the rotor 7 is reduced. For this reason, the amount of heat generated by the rotor 7 is reduced, so that a rise in temperature of the rotation sensor 11 connected to the rotor 7 can be suppressed. Therefore, malfunction of the rotation sensor 11 can be prevented. Moreover, since demagnetization of the permanent magnet 6 can be prevented, a decrease in torque can be prevented.

Embodiment 2.
FIG. 9 is a cross-sectional perspective view showing the internal structure of a quarter portion of the galvano scanner according to the second embodiment. In the second embodiment, the detour 5 is not provided within the rotor 7. The other configurations are the same as those in Embodiment 1, and redundant explanation will be omitted. In the second embodiment, the current magnetic flux path is a closed loop path passing through the rotating shaft 4, the detour 8, the stator core 12, the detour 8, and the rotating shaft 4 in this order. The portion of the path 5 is changed to the rotating shaft 4.

Since the material of the rotating shaft 4 has a lower magnetic permeability than the material of the detour 5, the current magnetic flux path of this second embodiment has a larger magnetic resistance than the current magnetic flux path of the first embodiment, but Since the detour 8 exists, the magnetic resistance is much smaller than the current magnetic flux path passing through the permanent magnet 6. Therefore, as in the first embodiment, the current magnetic flux 25 flows preferentially toward the current magnetic flux path passing through the detour 8, and almost no current magnetic flux flows through the permanent magnet 6.

As described above, according to the second embodiment, the current magnetic flux flowing through the permanent magnet 6 is reduced, and the eddy loss in the permanent magnet 6 can be reduced. As a result, demagnetization of the permanent magnet 6 and deviation of the operating temperature range of the rotation sensor 11 can be prevented. Furthermore, since the existing rotor can be used as is, it is easier to apply than the first embodiment and is advantageous in terms of cost.

Embodiment 3.
In the third embodiment, the detour path 8 and the detour path 5 are arranged only at the end portion of the permanent magnet 6 on both sides in the X direction where the rotation sensor 11 is installed.

According to the third embodiment, the detour 8 and the detour 5 are arranged only at the end where the rotation sensor 11 is installed. Therefore, when there is a greater concern about the temperature rise of the rotation sensor 11, it is possible to preferentially prevent the temperature rise of the rotation sensor 11, and this is advantageous in terms of cost.

Embodiment 4.
FIG. 10 is a partially enlarged vertical cross-sectional view of the galvano scanner according to the fourth embodiment. In the fourth embodiment, the length of the removed portion 10 of the stator core 12 in the X direction is set to be longer than the length of the permanent magnet 6 in the axial direction. Further, the length of the center hole 9a of the coil 9 in the X direction is set to be longer than the length of the permanent magnet 6 in the axial direction. The other configurations are the same as those in Embodiment 1, and redundant explanation will be omitted.

According to Embodiment 4, the gap between the rotor 7 and the stator core 12 becomes larger in the side region of the permanent magnet 6, making it difficult for current magnetic flux to flow through the permanent magnet 6. Therefore, the eddy loss generated in the permanent magnet 6 can be efficiently reduced.

Embodiment 5.
FIG. 11 is a cross-sectional perspective view showing the internal structure of a quarter portion of the stator 13 of the galvano scanner according to the fifth embodiment. FIG. 12 is a perspective view showing the overall configuration of the detour path 8 of the galvano scanner according to the fifth embodiment. In the first embodiment, four detours 8 were installed at positions in the X direction corresponding to both ends of the permanent magnet 6. In the fifth embodiment, a detour unit 80 having these four detours 8 is configured as one component. The detour unit 80 includes a ring portion 8c that connects the plurality of detours 8, and a plurality of detours 8 that are protrusions that protrude in the outer diameter direction from the ring portion 8c. Accordingly, the outer diameter of the portion of the rotating shaft 4 that faces the plurality of detours 8 of the rotor 7 is reduced. The other configurations are the same as those in Embodiment 1, and redundant explanation will be omitted.

According to the fifth embodiment, the detour 8 is configured as a detour unit 80 which is one component, so the current magnetic flux path can be formed as a closed circuit within the stator 13 without passing through the rotor 7. . Therefore, the occurrence of eddy currents and eddy losses in the permanent magnet 6 can be suppressed more reliably.

Embodiment 6.
FIG. 13 is a top view showing the configuration of a galvano scanner according to Embodiment 6. In the sixth embodiment, the deletion section 10 is divided into a plurality of

deletion holes

10a, 10b, and 10c. The other configurations are the same as those in Embodiment 1, and redundant explanation will be omitted.

In the sixth embodiment, since the removed portion 10 is divided into a plurality of removed

holes

10a, 10b, and 10c, the removed portion 10 can be provided without reducing the mechanical strength of the stator core 12.

Embodiment 7.
FIG. 14 is a sectional view showing essential parts of a galvano scanner according to Embodiment 7. FIG. 14 corresponds to a cross-sectional view taken along line IV-IV in FIG. In the first embodiment, the stator core 12 is provided with the cutout portion 10 of the through hole. In the seventh embodiment, the removed portion 10d has a groove shape in which a part of the inner diameter side is removed and the outer diameter side is connected. The deleted portion 10d has a groove shape extending in the X direction. The other configurations are the same as those in Embodiment 1, and redundant explanation will be omitted.

In the seventh embodiment, since the removed portion 10 is formed into a groove shape, the removed portion 10 can be provided without reducing the mechanical strength of the stator core 12. Thereby, the removed portion 10 can be provided without reducing the mechanical strength of the stator core 12.

Embodiment 8.
FIG. 15 is a cross-sectional perspective view showing the internal structure of a quarter portion of the stator 13 of the galvano scanner according to the eighth embodiment. In the eighth embodiment, the stator core 12 is provided with the deleted portion 10, but the stator 13 is not provided with the detour 8. Further, the detour 5 is not provided within the rotor 7. The other configurations are the same as those in Embodiment 1, and redundant explanation will be omitted.

In the eighth embodiment, since the stator core 12 is provided with the deleted portion 10, the current magnetic flux flowing into the permanent magnet 6 is reduced, and the eddy current generated due to the change in the current magnetic flux is reduced, and as a result, the eddy current generated in the rotor 7 is reduced. Eddy losses are reduced. For this reason, the amount of heat generated by the rotor 7 is reduced, so that a rise in temperature of the rotation sensor 11 connected to the rotor 7 can be suppressed. Therefore, malfunction of the rotation sensor 11 can be prevented. Moreover, since demagnetization of the permanent magnet 6 can be prevented, a decrease in torque can be prevented.

The configurations shown in the embodiments described above are examples of the contents of the present disclosure, and can be combined with other known techniques, and the configurations can be modified without departing from the gist of the present disclosure. It is also possible to omit or change parts.

1,101 Galvano scanner, 2 Housing, 3 Bearing, 4,104 Rotating shaft, 5,8 Detour, 6,106 Permanent magnet, 7,107 Rotor, 8c Ring part, 9,109 Coil, 9a Center hole, 10, 10d deletion part, 10a, 10b, 10c deletion hole, 11 rotation sensor, 12, 112 stator core, 13 stator, 14 galvanometer mirror, 20 air gap, 22 encoder plate, 23 sensor head, 24, 124 magnet magnetic flux, 25, 125 current magnetic flux , 80 detour unit.

Claims

A rotor having a permanent magnet in which different magnetic poles are alternately formed in the circumferential direction, and a rotating shaft disposed on both sides of the permanent magnet in the axial direction;
A stator comprising: a stator core; and a plurality of coils disposed on the inner diameter side of the stator core and on the outer diameter side of the rotor with a gap therebetween, and having a center hole that is a space;
an optical member connected to the rotation axis of the rotor;
Equipped with
The stator is
a first magnetic body disposed at a position corresponding to at least one end of the permanent magnet in the axial direction, inside the plurality of coils, and on the inner diameter side of the stator core;
A galvano scanner comprising:
The galvano scanner according to claim 1, wherein a first space in which at least a portion of an inner diameter side is removed is provided at a position corresponding to the center hole in the stator core.
The rotor is
The galvano scanner according to claim 1 or 2, further comprising: a second magnetic body facing the first magnetic body at a position corresponding to at least one end in the axial direction of the permanent magnet in the rotor.
The first magnetic body and the second magnetic body are
The galvano scanner according to claim 3, wherein the galvano scanner is provided at both ends of the permanent magnet in the axial direction.
A rotation sensor for detecting a rotation angle of the optical member is provided on one side of the rotation axis,
The first magnetic body and the second magnetic body are
The galvano scanner according to claim 3, wherein the rotation sensor is provided on one side of the rotation shaft.
The galvano scanner according to claim 2, wherein the first space is a through hole.
The galvano scanner according to claim 2, wherein the first space is a groove in which a portion of the inner diameter side is removed.
The galvano scanner according to claim 2, wherein the length of the first space in the axial direction is longer than the length of the permanent magnet in the axial direction.
The first space is
The galvano scanner according to claim 2, wherein the galvano scanner is divided into a plurality of parts in the axial direction.
The galvano scanner according to claim 1, wherein the first magnetic body has a ring portion and a plurality of protrusions protruding from the ring portion in an outer diameter direction, and is configured as one piece. .
A rotor having a permanent magnet in which different magnetic poles are alternately formed in the circumferential direction, and a rotating shaft disposed on both sides of the permanent magnet in the axial direction;
A stator comprising: a stator core; and a plurality of coils disposed on the inner diameter side of the stator core and on the outer diameter side of the rotor with a gap therebetween, and having a center hole that is a space;
an optical member connected to the rotation axis of the rotor;
Equipped with
A galvano scanner, wherein a first space in which at least a portion of an inner diameter side is removed is provided at a position corresponding to the center hole in the stator core.