Rotary drive device and pump

Abstract

Comprised are a rotor (20), a magnetic bearing (10), and a drive unit (30) that rotationally drives the rotor. The magnetic bearing comprises a bearing stator (12) and a ring-shaped bearing rotor member (11). The drive unit has a drive stator (32) and a ring-shaped drive rotor member (31). The bearing stator has a plurality of bearing stator cores (17) made from a magnetic material arranged on the outer peripheral side of the bearing rotor member, forming the bearing rotor member and a magnetic circuit, and a bearing coil (18) wound around the bearing stator core. The bearing stator core has a first part (17a) extending in a first direction orthogonal to the direction facing the bearing rotor member, and a pair of second parts (17b) extending to the bearing rotor member side from both ends of the first direction of the first part. The bearing coil is wound on the first part of the bearing stator core. The drive stator is formed to pass through a position in the first direction between the outer peripheral surface of the rotor and the first part, and between the pair of second parts of the bearing stator core.

Description

Technical Field

[0001] The present invention relates to a rotary drive device and a pump using a magnetic bearing.

Background Art

[0002] There is known a magnetic bearing that supports, non - contact, a load such as an impeller of a pump device by magnetic force, and a drive mechanism that rotationally drives the impeller (see, for example, Patent Document 1). As shown in FIG. 12, such a magnetic bearing 200 is composed of, for example, a bearing rotor member 206 provided on a rotor 201 including an impeller 200a, and a bearing stator 202 fixed to a housing 209.

[0003] Also, inside the magnetic bearing 200 in the radial direction, a drive mechanism 300 composed of a permanent magnet array 301 provided on the rotor 201 and an air - core coil array 302 provided on the housing 209 is incorporated. The rotor 201 is supported by the magnetic bearing 200 and is rotationally operated by the drive mechanism 300.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In such a magnetic bearing 200, a restoring force to a specified position with respect to the rotor 201 acts due to a magnetic flux φ passing through a magnetic circuit formed by a U - shaped stator core 204 constituting the bearing stator 202 and the bearing rotor member 206. Also, due to a magnetic flux φ passing through a magnetic circuit formed by the permanent magnet array 301 and the air - core coil array 302, a reaction force of the Lorentz force acting on the air - core coil array 302 acts on the permanent magnet array 301, and a rotational force to the rotor 201 acts.

[0006] However, since the bearing stator 202 of the magnetic bearing 200 is arranged on the outer side in the radial direction of the rotor 201, the hollow coil array 302 of the drive mechanism 300 is arranged on the inner side in the radial direction, and further the bearing rotor member 206 and the permanent magnet array 301 are arranged on the rotor 201, there is approximately a limit to reducing the radial dimension when regarded as a rotational drive device including the magnetic bearing 200 and the drive mechanism 300. For example, when this rotational drive device is applied to a pump device, there is a problem that it is difficult to reduce the size of the entire pump device.

[0007] The present invention has been made in view of the above circumstances, and an object thereof is to provide a rotational drive device and a pump capable of reducing the size by suppressing the radial dimension including the magnetic bearing and the drive mechanism.

Means for Solving the Problems

[0008] The rotary drive device according to the present invention is a rotary drive device including a rotor, a magnetic bearing that supports the rotor in a non-contact manner by magnetic force, and a drive unit that rotationally drives the rotor. The magnetic bearing includes a bearing stator that is disposed on the outer peripheral side of the rotor and supports the rotor in a non-contact manner by magnetic force, and an annular bearing rotor member made of a magnetic material that is provided on the rotor and forms a magnetic circuit together with the bearing stator. The drive unit includes a drive stator that is disposed on the outer peripheral side of the rotor and applies a rotational driving force to the rotor, and an annular drive rotor member that is disposed on the outer peripheral side of the bearing rotor member of the rotor and receives the rotational driving force from the drive stator. The bearing stator includes a plurality of bearing stator cores made of a magnetic material that are disposed on the outer peripheral side of the bearing rotor member and form a magnetic circuit together with the bearing rotor member, and a bearing coil wound around the bearing stator core. The bearing stator core has a first portion that extends in a first direction orthogonal to the direction facing the bearing rotor member, and a pair of second portions that extend from both ends of the first portion in the first direction toward the bearing rotor member side. The bearing coil is wound around the first portion of the bearing stator core. The drive stator is formed in an annular shape so as to pass through positions in the first direction between the outer peripheral surface of the rotor and the first portion of the bearing stator core and between the pair of second portions of the bearing stator core.

[0009] In one embodiment of the present invention, the bearing stator core is formed to further include a pair of third portions that extend in a direction approaching each other in the first direction from the ends of the pair of second portions on the bearing rotor member side and then extend toward the bearing rotor member side.

[0010] In another embodiment of the present invention, the bearing rotor member includes an annular bearing magnet and a pair of annular yokes arranged to sandwich the bearing magnet in the first direction. The pair of yokes includes a pair of fourth portions that cover both end faces of the bearing magnet in the first direction and extend in the first direction, and a pair of fifth portions that extend from ends of the pair of fourth portions opposite to the bearing magnet toward the bearing stator side. A spacer made of a non-magnetic material that supports the drive rotor member in a non-contact manner with the pair of yokes and the bearing magnet is disposed between opposing surfaces of the pair of fifth portions in the first direction.

[0011] In still another embodiment of the present invention, the bearing rotor member includes an annular bearing magnet and a pair of annular yokes arranged to sandwich the bearing magnet in the first direction. The pair of yokes includes a pair of fourth portions that cover both end faces of the bearing magnet in the first direction and extend in the direction of facing the bearing stator, and a pair of fifth portions that extend from ends of the pair of fourth portions opposite to the bearing stator toward each other in the first direction. A spacer made of a non-magnetic material that supports the drive rotor member in a non-contact manner with the pair of yokes and the bearing magnet is disposed between opposing surfaces of the pair of fourth portions on the bearing stator side of the bearing magnet in the first direction. A first gap is formed between the fifth portion and the bearing magnet, and a second gap is provided between opposing tip portions of the pair of fifth portions.

[0012] In still another embodiment of the present invention, a plurality of the bearing stators are arranged along the circumferential direction of the bearing rotor member on the outer side in the radial direction of the bearing rotor member, and are respectively opposed to the bearing rotor member in the radial direction.

[0013] In still another embodiment of the present invention, the drive stator includes an annular drive stator core made of a magnetic material having a plurality of magnetic poles along the circumferential direction of the drive rotor member, which faces the drive rotor member from the outer side in the radial direction, and a drive coil wound around a slot of the drive stator core.

[0014] The pump according to the present invention includes a rotor, a magnetic bearing that supports the rotor in a non-contact manner by magnetic force, a drive unit that rotationally drives the rotor, and a pump mechanism including an impeller attached to the rotor. The magnetic bearing includes a bearing stator that is disposed on the outer peripheral side of the rotor and supports the rotor in a non-contact manner by magnetic force, and an annular bearing rotor member made of a magnetic material that is provided on the rotor and forms a magnetic circuit together with the bearing stator. The drive unit includes a drive stator that is disposed on the outer peripheral side of the rotor and applies a rotational driving force to the rotor, and an annular drive rotor member that is disposed on the outer peripheral side of the bearing rotor member of the rotor and receives the rotational driving force from the drive stator. The bearing stator includes a plurality of bearing stator cores made of a magnetic material that are disposed on the outer peripheral side of the bearing rotor member and form a magnetic circuit together with the bearing rotor member, and a bearing coil wound around the bearing stator core. The bearing stator core has a first portion that extends in a first direction orthogonal to the direction facing the bearing rotor member, and a pair of second portions that extend from both ends of the first portion in the first direction toward the bearing rotor member. The bearing coil is wound around the first portion of the bearing stator core. The drive stator is formed in an annular shape so as to pass through positions in the first direction between the outer peripheral surface of the rotor and the first portion of the bearing stator core and between the pair of second portions of the bearing stator core.

[0015] In one embodiment of the present invention, the bearing stator core is formed to further include a pair of third portions that extend toward the bearing rotor member after extending in a direction approaching each other in the first direction from the ends of the pair of second portions on the bearing rotor member side.

[0016] In another embodiment of the present invention, the bearing rotor member includes an annular bearing magnet and a pair of annular yokes arranged to sandwich the bearing magnet in the first direction. The pair of yokes has a pair of fourth portions that cover both end faces of the bearing magnet in the first direction and extend in the first direction, and a pair of fifth portions that extend from ends of the pair of fourth portions on the side opposite to the bearing magnet toward the bearing stator side. A spacer made of a non-magnetic material that supports the drive rotor member in non-contact with the pair of yokes and the bearing magnet is disposed between opposing surfaces of the pair of fifth portions in the first direction.

[0017] In still another embodiment of the present invention, the bearing rotor member includes an annular bearing magnet and a pair of annular yokes arranged to sandwich the bearing magnet in the first direction. The pair of yokes has a pair of fourth portions that cover both end faces of the bearing magnet in the first direction and extend in the direction of facing the bearing stator, and a pair of fifth portions that extend from ends of the pair of fourth portions on the side opposite to the bearing stator toward each other in the first direction. A spacer made of a non-magnetic material that supports the drive rotor member in non-contact with the pair of yokes and the bearing magnet is disposed between opposing surfaces of the pair of fourth portions on the bearing stator side of the bearing magnet in the first direction. A first gap is formed between the fifth portion and the bearing magnet, and a second gap is provided between opposing tip portions of the pair of fifth portions.

[0018] In still another embodiment of the present invention, a plurality of the bearing stators are arranged along the circumferential direction of the bearing rotor member on the outer side in the radial direction of the bearing rotor member, and are respectively opposed to the bearing rotor member in the radial direction.

[0019] In still another embodiment of the present invention, the drive stator includes an annular drive stator core made of a magnetic material having a plurality of magnetic poles along the circumferential direction of the drive rotor member, which faces the drive rotor member from the outer side in the radial direction, and a drive coil wound around a slot of the drive stator core.

Advantages of the Invention

[0020] According to the present invention, it is possible to reduce the radial dimensions including the magnetic bearing and the drive mechanism and achieve miniaturization.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11A

Figure 11B

Figure 12

Embodiments for Carrying Out the Invention

[0022] Hereinafter, with reference to the accompanying drawings, a rotary drive device and a pump according to an embodiment of the present invention will be described in detail. However, the following embodiments do not limit the invention according to each claim, and not all combinations of the features described in the embodiments are essential for the solution means of the invention. Also, in the following embodiments, the same or corresponding components are denoted by the same reference numerals and redundant descriptions are omitted. Also, in the embodiments, the scales and dimensions of each component may be exaggerated or some components may be omitted.

[0023] [First Embodiment] [Configuration of Rotary Drive Device and Pump] FIG. 1 is a longitudinal sectional view schematically showing the overall configuration of a pump 100 to which a rotary drive device 90 according to the first embodiment is applied. FIG. 2 is an enlarged longitudinal sectional view schematically showing the rotary drive device 90, FIG. 3A is a top view schematically showing the overall configuration of the rotary drive device 90, and FIG. 3B is a top view schematically showing the overall configuration of the drive unit 30. Also, FIG. 4 is a perspective view schematically showing the overall configuration of the rotary drive device 90 with a part cut away, and FIG. 5 is a perspective view schematically showing the overall configuration of the bearing / rotor part 21 of the rotor 20 of the rotary drive device 90 with a part cut away.

[0024] As shown in FIGS. 1 to 5, the pump 100 according to the first embodiment includes a rotor 20, a magnetic bearing 10 that supports the rotor 20 in a non-contact manner by magnetic force, and a drive unit 30 that rotationally drives the rotor 20. The pump 100 also includes a pump mechanism including an impeller 22 attached to the rotor 20, and a control unit 60 that controls the entire pump mechanism. In this example, the pump 100 is shown. However, regarding only the function of rotationally driving the rotor 20 while supporting it in a non-contact manner, the rotor 20, the magnetic bearing 10, and the drive unit 30 can be regarded as a rotary drive device (bearingless motor) 90 using the magnetic bearing 10, as shown in FIGS. 3A and 4. And in this rotary drive device 90, regarding only the function of rotationally driving the rotor 20, as shown in FIG. 3B, the drive unit 30 can be regarded as a motor device (brushless motor).

[0025] In the following description, the rotation axis (Z-axis) direction of the rotor 20 is the Z-axis direction (also referred to as the axial direction or Z-direction), the radial direction of the rotor 20 is the X-axis direction and the Y-axis direction (also referred to as the radial direction, X-direction and Y-direction), the rotation direction around the X-axis is the Θ direction, and the rotation direction around the Y-axis is the Φ direction, respectively. Also, the X-axis, Y-axis, and Z-axis are orthogonal to each other. Further, the right side toward the paper surface of FIG. 1 is the front side of the pump 100, and the left side is the rear side.

[0026] The pump 100 is, for example, formed entirely in a cylindrical shape and has a front casing 41 on one side (front side) in the Z-axis direction. The front casing 41 forms a pump chamber A1 inside and has a cylindrical suction port 51 communicating with the pump chamber A1 at the front central portion. The front casing 41 also has a discharge port 52 communicating with the pump chamber A1 on the side surface.

[0027] At the rear end of the front casing 41, a rear casing 42 is connected in a sealed state by, for example, an O-ring 41a. The rear casing 42 forms a sealed space A including the pump chamber A1 together with the front casing 41. The rear casing 42 also forms a cylindrical space (accommodation space) A2 protruding rearward.

[0028] The outer side (outer peripheral side) in the radial direction on the rear side of the rear casing 42 is covered by a cylindrical housing 43. A pump base 43a for supporting the pump 100 is provided at the lower part of the housing 43. Further, the rear side of the housing 43 is covered by a rear cover 29 that houses the control unit 60 in the internal space. An insertion hole 29a for a harness or the like connected to the control unit 60 is formed in the central part of the rear cover 29, and a cable joint 28 is connected to the rear side of this insertion hole 29a.

[0029] The rotor 20 is accommodated in the sealed space A in a state where it can float (be non-contact supported). The rotor 20 is, for example, entirely formed of a non-magnetic material such as a resin material, and integrally formed with an impeller 22 provided on the front side which is one end in the Z-axis direction, and an annular bearing / rotor part 21 provided on the rear side which is the other end in the Z-axis direction. The impeller 22 is accommodated in a pump chamber A1 inside the front casing 41, and together with this pump chamber A1, constitutes a pump mechanism.

[0030] On the other hand, the rear casing 42 has a front flange part 42a and a cylindrical protruding part 42b protruding rearward from the central part of this flange part 42a, and the bearing / rotor part 21 is accommodated in a cylindrical space A2 inside the cylindrical protruding part 42b of the rear casing 42. A cylindrical stator base 44 is provided inside the housing 43. The stator base 44 forms an annular space A3 that surrounds the cylindrical space A2 between the outer peripheral surfaces of the flange part 42a and the cylindrical protruding part 42b of the rear casing 42. And in this annular space A3, a bearing stator 12 and a motor stator 32 as a drive stator, which will be described later, are provided.

[0031] The magnetic bearing 10 has a bearing rotor member 11 made of an annular magnetic material attached to the inner peripheral side of the bearing / rotor part 21 of the rotor 20, and a bearing stator 12 disposed, for example, at a predetermined interval radially outside the bearing rotor member 11.

[0032] The bearing rotor member 11 includes, for example, as shown in FIG. 5, a bearing magnet 13 made of a neodymium magnet formed in an annular shape, and a pair of yokes 14, 15 made of annular electromagnetic soft iron that are concentric with the bearing magnet 13 and are arranged so as to sandwich both end faces of the bearing magnet 13 in the axial direction (Z-axis direction) in the axial direction.

[0033] The bearing magnet 13 is magnetized such that, for example, the N pole and the S pole face each other in the axial direction and the same poles are present over the entire circumference in the circumferential direction. Note that, as shown in FIG. 2, the bearing magnet 13 supplies a bias magnetic flux φ1 to a magnetic circuit formed by a bearing stator core 17, which will be described later, of the bearing rotor member 11 and the bearing stator 12.

[0034] On the other hand, as shown in FIGS. 3A and 3B, for example, a plurality of bearing stators 12 are arranged at four locations in the circumferential direction of the bearing rotor member 11 with an angle of 90°. Among these bearing stators 12, for example, a pair of bearing stators 12 (12x) facing each other in the X-axis direction control the position of the rotor 20 in the X-axis direction and the angle in the Φ direction under the control of the control unit 60, and a pair of bearing stators 12 (12y) facing each other in the Y-axis direction control the position of the rotor 20 in the Y-axis direction and the angle in the Θ direction. Further, these bearing stators 12 (12x, 12y) control the height of the rotor 20 in the Z-axis direction.

[0035] Note that a plurality (for example, four in this case) of displacement sensors 16 capable of detecting displacements in the radial direction and each rotational direction of the bearing rotor member 11 are arranged on the stator base 44 at an angle of 45° with respect to each of the bearing stators 12 (that is, intersecting the X-axis direction and the Y-axis direction at angles of 45° respectively).

[0036] These displacement sensors 16 include, for example, eddy current sensors, but are not limited thereto, and various sensors can be adopted. Further, the number of bearing stators 12 is not limited to the above number, and various forms such as, for example, 6, 8, 10, 12, 16, etc. can be adopted. In addition, although not shown in the drawings, the displacement sensors include sensors provided on, for example, a stator base 44 or the like so as to face the bearing / rotor portion 21 in the axial direction and capable of detecting displacements in the axial direction and the rotational direction of the bearing rotor member 11 and the like together with the above displacement sensors 16. Note that the arrangement mode and the number of the displacement sensors 16 and the like are not limited to this, and various forms can be adopted.

[0037] The bearing stator 12 has, for example, a bearing stator core 17 made of a magnetic material such as a laminated electromagnetic steel sheet, and a bearing coil 18 wound around the bearing stator core 17. The longitudinal cross-sectional shape of the bearing stator core 17 is substantially C-shaped (U-shaped) with the bearing rotor member 11 side being an open end. Specifically, as shown in FIG. 2, the bearing stator core 17 has a longitudinal cross-sectional shape including a first portion 17a extending in a first direction (in this example, the Z-axis direction) orthogonal to the direction (radial direction) facing the bearing rotor member 11, and a pair of second portions 17b extending from both ends of the first portion 17a in the Z-axis direction toward the bearing rotor member 11 side. Note that the bearing coil 18 is wound around the first portion 17a.

[0038] As shown in FIG. 3A, the outer peripheral surface of the bearing rotor member 11 is formed as a curved surface, while the magnetic pole surface 17d (see FIG. 2) of the bearing stator core 17 is formed as a flat surface. Specifically, the magnetic pole surface 17d is formed on the same plane extending in the X-axis direction or the Y-axis direction and the Z-axis direction. Generally, when the magnetic pole surface 17d of the bearing stator core 17 is formed as a curved surface along the outer peripheral surface of the bearing rotor member 11, a bias magnetic flux φ1 of the magnetic field concentrates at the circumferential end of the magnetic pole surface 17d. On the other hand, if the magnetic pole surface 17d is formed as a flat surface, it is possible to prevent such concentration of the bias magnetic flux φ1.

[0039] On one hand, the pair of yokes 14, 15 of the bearing rotor member 11 has a shape including, for example, a pair of fourth portions 14a, 15a whose longitudinal cross-sectional shape covers both end faces of the bearing magnet 13 in the first direction and extends in the first direction, and a pair of fifth portions 14b, 15b extending from the ends of the pair of fourth portions 14a, 15a on the side opposite to the bearing magnet 13 toward the bearing stator 12 side.

[0040] The drive unit 30 includes a motor magnet 31 as an annular drive rotor member disposed on the outer peripheral side of the bearing / rotor portion 21 of the rotor 20, that is, on the outer side in the radial direction of the bearing magnet 13 of the bearing rotor member 11, and a motor stator 32 as a drive stator disposed, for example, at a predetermined interval from the motor magnet 31 on the outer side in the radial direction of the motor magnet 31. The motor stator 32 imparts a rotational driving force to the rotor 20, and the motor magnet 31 receives the rotational driving force from the motor stator 32.

[0041] The motor magnet 31 is made of, for example, a neodymium magnet magnetized in four poles in the radial direction. The motor magnet 31 is supported in a non-contact manner by the pair of yokes 14, 15 and the bearing magnet 13 by an annular spacer 19 disposed between the opposing surfaces in the first direction of the pair of fifth portions 14b, 15b of the pair of yokes 14, 15, and is disposed so as to be within the radial dimension (diameter) L1 of the bearing rotor member 11. Note that the spacer 19 is formed of a non-magnetic resin material or a metal material.

[0042] The motor stator 32 has an annular motor stator core 33 made of a magnetic material having a plurality of magnetic poles along the circumferential direction of the motor magnet 31, facing the motor magnet 31 from the radially outer side. The motor stator core 33 includes, for example, six slots having a concave magnetic pole surface along the outer peripheral surface of the motor magnet 31. The motor stator 32 also has motor coils 34 as drive coils wound in each slot of the motor stator core 33. The motor stator 32 is formed in an annular shape so as to pass through positions in the Z direction between the outer peripheral surface of the rotor 20 and the first portion 17a of the bearing stator core 17, and between a pair of second portions 17b of the bearing stator core 17. That is, the motor stator 32 is disposed inside the bearing stator 12 in the radial direction of the bearing coil 18, between a pair of second portions 17b of the bearing stator core 17, and is arranged to be within the radial dimension L2 of the bearing stator 12. Further, as shown in FIGS. 3A and 3B, three Hall ICs 16a are provided at an angle of 60° between four adjacent slots in the circumferential direction of the motor stator 32 in order to detect the rotation angle of the bearing rotor member 11 around the Z axis. Note that the arrangement mode and number of the Hall ICs 16a are not limited to this, and various forms can be adopted.

[0043] And the motor stator 32 configured as described above is configured as a stator of a three-phase six-slot, four-pole sensorless brushless motor as shown in FIG. 3B, and generates a magnetic flux φ2 to rotationally drive the rotor 20 including the magnetically coupled motor magnet 31. Note that in the drawings other than FIG. 1, illustration of non-magnetic bodies including the periphery of the bearing / rotor unit 21 is omitted. Further, the drive unit 30 is not limited to the three-phase six-slot, four-pole brushless motor as described above. For example, a configuration including a motor stator 32 having a 10-pole motor magnet 31 and a 12-slot motor stator core 33, or a configuration including a motor stator 32 having a 14-pole motor magnet 31 and a 12-slot motor stator core 33 can be adopted. Note that when the drive unit 30 is a sensorless brushless motor, for example, the Hall ICs 16a may not be provided.

[0044] The control unit 60 includes, for example, a first substrate 61 such as a driver board equipped with MOS-FETs or the like for driving the bearing coil 18 of the magnetic bearing 10 and the motor coil 34 of the drive unit 30, a second substrate 62 such as a CPU board for controlling the magnetic bearing 10 and the drive unit 30, and a third substrate 63 such as an encoder board for processing signals from various sensors. Based on detection signals such as voltage changes from the entire displacement sensor including the displacement sensor 16 described above, the control unit 60 detects the displacement of the rotor 20 in each direction and each rotational direction by the third substrate 63, and accordingly, the second substrate 62 finely controls the current flowing through the bearing coil 18 of the bearing stator 12 of the magnetic bearing 10. Thereby, it is possible to control the position of the rotor 20 in the X-axis direction and the angle in the Φ direction, the position in the Y-axis direction and the angle in the Θ direction, and the height in the Z-axis direction in real time, and perform rotational position correction of the rotor 20. Further, based on the detection signal from the Hall IC 16a, the control unit 60 detects a magnetic field change by the second substrate 62, and finely controls the current flowing through the motor coil 34 of the motor stator 32 of the drive unit 30, and controls the rotational operation of the rotor 20 by, for example, the first substrate 61.

[0045] [Operation of Rotation Drive Device and Pump] Next, the operation of the pump 100 to which the rotation drive device 90 configured as described above is applied will be described. In the pump 100 having the above-described configuration, the magnetic circuit of the magnetic bearing 10 and the magnetic circuit of the drive unit 30 are independent of each other and do not interfere. That is, as shown in FIGS. 2 and 3A, the magnetic circuit through which the magnetic flux φ1 formed by the magnetic bearing 10 passes is formed along the XZ plane and the YZ plane parallel to the rotation axis Z of the rotor 20. On the other hand, as shown in FIGS. 2 and 3B, the magnetic circuit through which the magnetic flux φ2 formed by the drive unit 30 passes is formed along the XY plane orthogonal to the rotation axis Z of the rotor 20. The motor stator 32 is formed in an annular shape so as to pass through the space between the pair of second portions 17b of the bearing stator core 17, and the motor magnet 31 is disposed on the outer peripheral side of the bearing rotor member 11. Therefore, the magnetic circuit of the magnetic bearing 10 is formed so as to surround the outside of the magnetic circuit of the drive unit 30.

[0046] The control unit 60 controls the current flowing through the bearing coil 18 as described above so as to correct the displacements in the axial directions of the X, Y, and Z axes of the rotor 20 detected by the displacement sensor 16 or the like and the inclinations in the Φ direction and the Θ direction, and adjusts the control magnetic flux generated by the bearing coil 18. As a result, the rotor 20 is supported by the magnetic bearing 10 in a non-contact state while maintaining a predetermined position and a predetermined posture by the magnetic bearing 10.

[0047] When three-phase AC power is supplied to the motor coil 34 of the motor stator 32 of the drive unit 30 in this state, the three-phase brushless motor operates, and the rotor 20 rotates in a predetermined rotation direction. When the rotor 20 rotates, since the impeller 22 rotates in a non-contact manner within the sealed space A, the transfer fluid is introduced into the pump chamber A1 through the suction port 51, and the transfer fluid is discharged from the pump chamber A1 to the outside through the discharge port 52.

[0048] [Advantages of the Embodiment] According to the pump 100 using the rotary drive device 90 according to the present embodiment, the bearing stator 12 of the magnetic bearing 10 and the motor stator 32 of the drive unit 30 are arranged outside the rotor 20, and moreover, the motor stator 32 is arranged in the inner space of the bearing stator core 17 of the magnetic bearing 10. For this reason, it is not necessary to arrange a stator inside the rotor 20, and it is possible to reduce the radial dimension (diameter) Lr of the entire rotary drive device 90 as compared with the conventional one.

[0049] Also, since the dimension of the bearing stator core 17 in the Z-axis direction is set to a dimension such that the motor stator 32 can be accommodated between the pair of second portions 17b, it becomes longer than when the motor stator 32 does not exist. However, since the bearing coil 18 of the bearing stator 12 is wound around the first portion 17a extending in the Z-axis direction of the bearing stator core 17 and does not protrude in the Z-axis direction, the dimension Lh of the entire rotation drive device 90 in the Z-axis direction can be made the same as the height of the bearing stator core 17 in the Z-axis direction. Therefore, it is possible to suppress the dimension Lh of the entire rotation drive device 90 in the Z-axis direction to be slightly larger than that of the conventional one. Accordingly, it is possible to minimize the dimensions of the rotation drive device 90 including the magnetic bearing 10 and the drive unit 30 in the radial and axial directions as much as possible, and to achieve sufficient miniaturization as a whole.

[0050] Specifically, for example, when the radial dimension of a conventional rotation drive device is taken as 100%, the radial dimension Lr of the rotation drive device 90 can be set to about 70% thereof, and the dimension Lh of the rotation drive device 90 in the Z-axis direction can be suppressed to an increase of about 1.1 times that of the Z-axis dimension (height) of the conventional rotation drive device. Therefore, the entire pump 100 employing the rotation drive device 90 can also be miniaturized. And in the rotation drive device 90 configured in this way, the magnetic bearing 10 supports the rotor 20 on both sides in the Z direction, and the drive unit 30 drives in the middle of the rotor 20 in the Z direction, so the balance of the driving force with respect to the rotor 20 is very good. Also, since the magnetic bearing 10 and the drive unit 30 do not affect each other's magnetic circuits, they do not inhibit each other's performance.

[0051] Furthermore, since the bearing stator 12 and the motor stator 32 are located outside the rotor 20, and the motor stator 32 is located inside the inner space of the bearing stator core 17 and straddles both sides in the axial direction by the bearing stator core 17, compared with a general rotary drive device having a structure that supports both ends in the axial direction of the drive unit 30 with four or more axes using two two-axis magnetic bearings, the structure is simple and it is possible to achieve weight reduction and size reduction at low cost. At the same time, since the magnetic levitation of the rotor 20 is controlled by the two-axis control magnetic bearing 10, the control structure does not become complicated, the circuit configuration of the control system is simplified, for example, the number of heating elements (such as the bearing coil 18 and the MOS-FET of the first substrate 61) is reduced, and the configuration of the control unit 60 and the substrate design can be simplified. In the case of the pump 100 of the present embodiment, since the impeller 22 is arranged on one side of the rotor 20, when the rotor 20 is inclined with respect to the Z axis, the rotor 20 is inclined with the position close to the impeller 22 on the Z axis as the rotation center. Therefore, if the displacement sensor 16 is arranged at a position away from the impeller 22, preferably at the center in the Z-axis direction of the bearing / rotor unit 21, the displacement sensor 16 can detect the position of the rotor 20 in the X-axis direction and the angle in the Φ direction, and the position of the rotor 20 in the Y-axis direction and the angle in the Θ direction. Therefore, the inclination of the rotating shaft can also be sufficiently controlled by two-axis control.

[0052] [Configuration of Other Pumps to Which the Rotary Drive Device is Applied] FIG. 6 is a perspective view schematically showing the overall configuration of another pump 101 to which the rotary drive device 90 is applied, with a part thereof being transparent. As shown in FIG. 6, the pump 101 inserts a rotor 20 integrated with the impeller 22 of the rotary drive device 90 into, for example, the inside of the flanged pipe 102, and arranges the motor stator 32 of the drive unit 30 and the bearing stator 12 of the magnetic bearing 10 on the outer peripheral side of the rotor 20 installation location of the flanged pipe 102. That is, the rotor 20 is magnetically levitated by the magnetic bearing 10 and does not have the motor stator 32 arranged inside, so it can be easily arranged in the flanged pipe 102. Further, the bearing stator 12 and the motor stator 32 that support and drive the rotor 20 only need to be mounted on the outside of the flanged pipe 102. With such a configuration, it is possible to use the pump 101, for example, as a part of the pipe material, while eliminating the need for complicated processing of the flanged pipe 102 and installation work of the pump device.

[0053] [Second Embodiment] [Another Configuration of Rotary Drive Device] FIG. 7 is an enlarged longitudinal sectional view schematically showing the rotary drive device 90A according to the second embodiment, and FIG. 8 is a top view schematically showing the overall configuration of the rotary drive device 90A. In the following description including FIGS. 7 and 8, the same reference numerals are given to the same components as those in the first embodiment, so the overlapping descriptions will be omitted below.

[0054] The rotary drive device 90A of the second embodiment is different from the rotary drive device 90 of the first embodiment in that, for example, the longitudinal sectional shape of the bearing stator core 17 of the bearing stator 12 of the magnetic bearing 10 is different. That is, in addition to the above-described first portion 17a and second portion 17b, the bearing stator core 17 is formed to further include a pair of third portions 17c whose longitudinal sectional shape extends in a direction approaching each other in the first direction (in this case, the Z-axis direction) from the end portions on the bearing rotor member 11 side of the pair of second portions 17b, and then extends toward the bearing rotor member 11 side.

[0055] In other words, in the vertical cross-sectional shape, the bearing stator core 17 has a pair of keyhole-shaped portions at both ends in the Z-axis direction of the first portion 17a around which the bearing coil 18 is wound, leading toward the bearing rotor member 11, in the C-shaped open-end portion (for example, see FIG. 12) that would originally extend, and has a shape with the open ends approaching each other.

[0056] When the bearing stator core 17 has such a shape, the length l of the bearing coil 18 in the Z-axis direction can be made larger than the distance La between the opposing surfaces in the Z-axis direction of the pair of third portions 17c on the open-end side of the bearing stator core 17. Also, the width on the open-end side of the bearing stator core 17, that is, the distance Lb between the surfaces on the side opposite to the opposing surfaces in the Z-axis direction of the pair of third portions 17c, can be made smaller than the original length of the bearing stator core 17 in the Z-axis direction (that is, the dimension of the rotational drive device 90A in the Z-axis direction) Lh, and can be made substantially equal to the length Lc of the bearing rotor member 11 in the Z-axis direction. Note that the motor stator 32 of the drive unit 30 is disposed between the pair of second portions 17b of the bearing stator core 17 and between the pair of third portions 17c.

[0057] Here, generally, it is known that the restoring force by a conventional magnetic bearing 200 (see FIG. 12) is larger when the length of the stator core 204 of the bearing stator 202 and the axial thickness Lf of the bearing rotor member 206 are substantially equal and as thin as possible. On the other hand, although the magnetic flux φ is controlled by the coil 205 of the bearing stator 202, it is desirable to make the inductance of the coil 205 as small as possible in order to enhance the responsiveness.

[0058] Since the inductance of this coil 205 is proportional to the cross-sectional area S of the coil 205 and inversely proportional to the coil length l, in order to increase the responsiveness of the coil 205, it is necessary to wind the coil 205 around the stator core 204 such that the cross-sectional area S of the coil 205 is made smaller and the length l of the coil 205 is made longer.

[0059] However, when the coil length l increases, the axial thickness Lf of the bearing rotor member 206 of the rotor 201 also increases, resulting in a decrease in the restoring force of the rotor 201. In particular, the restoring torque when the rotor 201 is tilted decreases, and the dimensions of the axial magnetic bearing 200 in the axial direction increase.

[0060] Here, as described above, the restoring force for the position and inclination of the rotor 20 by the magnetic bearing 10 is such that the length Lb in the Z-axis direction of the open end (third portion 17c) of the bearing stator 12 is substantially equal to the length Lc in the Z-axis direction of the bearing rotor member 11, and the shorter the length Lc in the Z-axis direction of the bearing rotor member 11, the greater it is. In this regard, according to the magnetic bearing 10 of the rotary drive device 90A of the second embodiment, the length Lb in the Z-axis direction of the portion (third portion 17c) facing the bearing rotor member 11 at the open end can be made shorter than that of the conventional C-shaped stator core 204 shown in FIG. 12.

[0061] Therefore, while maintaining the number of turns N of the bearing coil 18, the length Lc in the Z-axis direction of the bearing rotor member 11 can be made shorter than that of the conventional one. Thus, it is possible to reduce the size of the bearing rotor member 11 in the Z-axis direction while ensuring sufficient restoring force. Also, as described above, in order to enhance the responsiveness of the magnetic bearing 10, it is necessary to minimize the inductance of the bearing coil 18. In this regard, according to the magnetic bearing 10 according to the second embodiment, the length Ld of the first portion 17a around which the bearing coil 18 of the bearing stator core 17 is wound can be sufficiently ensured. Therefore, the length l in the Z-axis direction of the bearing coil 18 can be increased, and the cross-sectional area S of the bearing coil 18 can be reduced, thereby suppressing the inductance of the bearing coil 18 and improving the responsiveness. In addition, in order to maximize the attractive force of the bearing magnet 13, it is desirable that the width in the Z-axis direction of each third portion 17c (pole projection) of the bearing stator core 17 is substantially equal to the thickness in the Z-axis direction of the yokes 14, 15.

[0062] According to the rotary drive device 90A of the second embodiment, the same operational effects as those of the rotary drive device 90 of the first embodiment can be achieved, and the axial dimension of the bearing rotor member 11 can be made smaller. Therefore, the miniaturization of the bearing / rotor part 21, and thus the miniaturization of the rotor 20, can be promoted, and further miniaturization of the whole can be achieved.

[0063] [Third Embodiment] [Other Configuration of Rotary Drive Device] FIG. 9 is an enlarged longitudinal sectional view schematically showing a rotary drive device 90B according to the third embodiment. As shown in FIG. 9, the rotary drive device 90B of the third embodiment is different from the rotary drive device 90A of the second embodiment in the configuration of the bearing rotor member 11 in the magnetic bearing 10, the shape of the motor stator 32, and the arrangement mode in the inner space of the bearing stator core 17.

[0064] That is, the bearing rotor member 11 has, for example, an annular bearing magnet 13 and a pair of annular yokes 14 and 15 that are concentric with the bearing magnet 13 and are arranged to sandwich the bearing magnet 13 from both sides in the axial direction. However, the details are different. In the third embodiment, the pair of yokes 14 and 15 has, for example, a substantially U-shaped longitudinal sectional shape with the bearing stator 12 side as an open end and the middle in the Z-axis direction being cut off.

[0065] Specifically, the longitudinal sectional shape of the pair of yokes 14 and 15 has a pair of fourth portions 14a and 15a that extend along a second direction (here, the radial direction (X-axis direction)) orthogonal to the Z-axis direction while covering both end faces of the bearing magnet 13 in the first direction (here, the Z-axis direction), and a pair of fifth portions 14b and 15b that extend from the ends of the pair of fourth portions 14a and 15a on the side opposite to the bearing stator 12 in a direction approaching each other in the Z-axis direction. The inner peripheral portions of the fourth portions 14a and 15a protrude inward and outward from the inner peripheral portion and the outer peripheral portion of the bearing magnet 13.

[0066] Between the opposing surfaces in the first direction on the bearing stator 12 side of the bearing magnets 13 of the fourth parts 14a and 15a, an annular spacer 19 supports a motor magnet 31 in a non-contact manner with respect to the yokes 14 and 15 and the bearing magnets 13 so as to fit within the dimension (diameter) L1 of the bearing rotor member 11. A first gap g1 is formed between the fifth parts 14b and 15b and the bearing magnets 13. Also, a second gap g2 is provided between the opposing tip portions of these pair of fifth parts 14b and 15b.

[0067] When the bearing rotor member 11 has such a shape, the first gap g1 can prevent both magnetic poles of the bearing magnet 13 from approaching the fifth parts 14b and 15b too closely. Therefore, the bias magnetic flux φ1 from the bearing magnet 13 can be stably supplied to the bearing stator 12. Also, since a magnetic circuit is formed by the fifth parts 14b and 15b with a small magnetic resistance in parallel with the bearing magnet 13 with a large magnetic resistance, it becomes possible to pass the control magnetic flux φ3 generated by the bearing coil 18 through the bearing rotor member 11 with minimal loss. However, if there is no second gap g2, both magnetic poles of the bearing magnet 13 will short-circuit through the fifth parts 14b and 15b. Therefore, considering the balance between the stable supply of the bias magnetic flux φ1 to the bearing stator 12 side and the magnetic resistance of the magnetic circuit through which the control magnetic flux φ3 passes, it is desirable to appropriately set the width of the second gap g2.

[0068] On the other hand, in this embodiment, unlike the structure shown in FIG. 7, the motor coil 34 that constitutes the motor stator 32 is not positioned between the third portions 17c of the bearing stator core 17, but is accommodated between the second portions 17b. Only the tip portion of the motor stator core 33 that extends toward the rotor 20 is positioned between the third portions 17c of the bearing stator core 17. That is, the motor stator 32 has the motor stator core 33 and the motor coil 34 accommodated between a pair of second portions 17b of the bearing stator core 17 inside the radial direction of the bearing coil 18 in the bearing stator 12, and the extended portion of the motor stator core 33 is arranged between a pair of third portions 17c so as to be accommodated within the radial dimension L2 of the bearing stator 12.

[0069] According to the rotary drive device 90B of this third embodiment, the same operational effects as those of the rotary drive device 90A of the second embodiment can be achieved, and the axial dimension of the bearing rotor member 11 can be further reduced. Therefore, the miniaturization of the bearing / rotor unit 21 and the rotor 20 can be further promoted, and the overall miniaturization can be further achieved.

[0070] [Fourth Embodiment] FIG. 10 is a top view schematically showing the drive unit 30 of the rotary drive device 90C according to the fourth embodiment. In this embodiment, as the displacement sensor 16, six displacement sensors 16 composed of eddy current sensors or the like are provided at an angle of 60° between six slots adjacent to each other in the circumferential direction of the motor stator 32. The Hall IC 16a is arranged in the vicinity of some of the displacement sensors 16.

[0071] When the displacement sensors 16 are arranged in this way, each slot of the motor stator 32 and the displacement sensors 16 do not interfere with each other in terms of position. Therefore, the displacement sensors 16 can be arranged at the central portion in the Z-axis direction of the bearing rotor member 11. Thereby, the radial displacement and inclination of the rotor 20 can be detected at an appropriate position.

[0072] [Fifth Embodiment] FIG. 11A is a longitudinal sectional view schematically showing the overall configuration of a pump 100A to which a rotary drive device 90D according to a fifth embodiment is applied, and FIG. 11B is a top view schematically showing a drive unit 30 of the rotary drive device 90D. In this embodiment, four displacement sensors 16 are arranged on the inner circumferential side of the bearing rotor member 11 with an angle of 90° in the circumferential direction. That is, a cylindrical protrusion 42b extending rearward of the rear casing 42 has a cylindrical protrusion 42c extending forward at the center, and the bearing rotor member 11 is arranged in an annular space A4 formed by the cylindrical protrusion 42b and the cylindrical protrusion 42c. Then, four displacement sensors 16 are arranged inside the cylindrical protrusion 42c. In this case, since the arrangement position of the displacement sensor 16 is not restricted by the motor stator 32, the displacement sensor 16 can be easily arranged at the central portion of the bearing rotor member 11 in the Z-axis direction.

[0073] Also in this embodiment, as in the fourth embodiment, the displacement sensor 16 can be arranged at the central portion of the bearing rotor member 11 in the Z-axis direction, so that the radial displacement and inclination of the rotor 20 can be detected at an appropriate position.

[0074] As described above, some embodiments of the present invention have been described. However, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope.

Description of Reference Numerals

[0075] 10 Magnetic bearing 11 Bearing rotor member 12 Bearing stator 13 Bearing magnet 14, 15 Yoke 16 Displacement sensor 17 Bearing stator core 17a Part 1 17b Part 2 17c Part 3 18 Bearing coil 20 Rotor 30 Driving part 31 Motor magnet 32 Motor stator 33 Motor stator core 34 Motor coil 90 Rotary drive device 100 Pump

Claims

1. A rotor, a magnetic bearing that supports the rotor in a non-contact manner by magnetic force, a drive unit that rotationally drives the rotor, and a rotational drive device comprising: wherein the magnetic bearing comprises a bearing stator that is disposed on the outer peripheral side of the rotor and supports the rotor in a non-contact manner by magnetic force, and an annular bearing rotor member made of a magnetic material that is provided on the rotor and forms a magnetic circuit together with the bearing stator; the drive unit comprises a drive stator that is disposed on the outer peripheral side of the rotor and applies a rotational driving force to the rotor, and an annular drive rotor member that is disposed on the outer peripheral side of the bearing rotor member of the rotor and receives the rotational driving force from the drive stator; the bearing stator comprises a plurality of bearing stator cores made of a magnetic material that are disposed on the outer peripheral side of the bearing rotor member and form a magnetic circuit together with the bearing rotor member, and a bearing coil wound around the bearing stator cores; the bearing stator cores comprise a first portion extending in a first direction orthogonal to the direction facing the bearing rotor member, and a pair of second portions extending from both ends of the first portion in the first direction toward the bearing rotor member side; the bearing coil is wound around the first portion of the bearing stator cores, and the drive stator is formed so as to pass through positions in the first direction between the outer peripheral surface of the rotor and the first portion of the bearing stator cores, and between the pair of second portions of the bearing stator cores. A rotational drive device characterized by the above.

2. The bearing stator cores are formed to further comprise a pair of third portions that extend in a direction approaching each other in the first direction from the ends of the pair of second portions on the bearing rotor member side, and then extend toward the bearing rotor member side. The rotational drive device according to Claim 1, characterized by the above.

3. The bearing rotor member comprises an annular bearing magnet, and a pair of annular yokes disposed so as to sandwich the bearing magnet in the first direction; the pair of yokes comprise a pair of fourth portions that cover both end faces of the bearing magnet in the first direction and extend in the first direction, and a pair of fifth portions that extend from the ends of the pair of fourth portions on the side opposite to the bearing magnet toward the bearing stator side. A spacer made of a non-magnetic material that supports the drive rotor member in a non-contact manner with the pair of yokes and the bearing magnet is disposed between the opposing surfaces of the pair of fifth portions in the first direction. The rotary drive device according to claim 1 or 2, characterized in that.

4. The bearing rotor member includes an annular bearing magnet, and a pair of annular yokes arranged so as to sandwich the bearing magnet in the first direction. The pair of yokes includes a pair of fourth portions that cover both end faces of the bearing magnet in the first direction and extend in a direction facing the bearing stator, and a pair of fifth portions that extend from the ends of the pair of fourth portions on the side opposite to the bearing stator toward each other in the first direction. A spacer made of a non-magnetic material that supports the drive rotor member in a non-contact manner with the pair of yokes and the bearing magnet is disposed between the opposing surfaces of the pair of fourth portions on the bearing stator side of the bearing magnet in the first direction. A first gap is formed between the fifth portion and the bearing magnet. A second gap is provided between the opposing tip portions of the pair of fifth portions. The rotary drive device according to claim 1 or 2, characterized in that.

5. The bearing stator is arranged in plurality along the circumferential direction of the bearing rotor member on the outer side in the radial direction of the bearing rotor member, and faces the bearing rotor member in the radial direction respectively. The rotary drive device according to any one of claims 1 to 4, characterized in that.

6. The drive stator includes an annular drive stator core made of a magnetic material having a plurality of magnetic poles along the circumferential direction of the drive rotor member, which faces the drive rotor member from the outer side in the radial direction, and a drive coil wound around a slot of the drive stator core. The rotary drive device according to any one of claims 1 to 5, characterized in that.

7. A rotor, a magnetic bearing that supports the rotor in a non-contact manner by magnetic force, a drive unit that rotates the rotor, a pump mechanism including an impeller attached to the rotor, A pump comprising: The magnetic bearing includes a bearing stator disposed on the outer peripheral side of the rotor and supporting the rotor in a non-contact manner by magnetic force, and an annular bearing rotor member made of a magnetic material provided on the rotor and forming a magnetic circuit together with the bearing stator. The drive unit A drive stator disposed on the outer peripheral side of the rotor to apply a rotational driving force to the rotor; An annular drive rotor member disposed on the outer peripheral side of the bearing rotor member of the rotor to receive the rotational driving force from the drive stator, and having; The bearing stator is A plurality of bearing stator cores made of a magnetic material disposed on the outer peripheral side of the bearing rotor member to form a magnetic circuit together with the bearing rotor member; A bearing coil wound around the bearing stator core, and having; The bearing stator core is A first portion extending in a first direction orthogonal to the facing direction with the bearing rotor member; A pair of second portions extending from both ends of the first portion in the first direction toward the bearing rotor member, and having; The bearing coil is wound around the first portion of the bearing stator core; The drive stator is formed so as to pass through positions in the first direction between the outer peripheral surface of the rotor and the first portion of the bearing stator core, and between the pair of second portions of the bearing stator core. A pump characterized by the above.

8. The bearing stator core is Formed to further have a pair of third portions extending in a direction approaching each other in the first direction from the ends of the pair of second portions on the bearing rotor member side, and then extending toward the bearing rotor member side. The pump according to claim 7, characterized by the above.

9. The bearing rotor member is An annular bearing magnet; A pair of annular yokes disposed so as to sandwich the bearing magnet in the first direction, and having; The pair of yokes is A pair of fourth portions covering both end faces of the bearing magnet in the first direction and extending in the first direction; A pair of fifth portions extending from the ends of the pair of fourth portions on the side opposite to the bearing magnet toward the bearing stator side, and having; A spacer made of a non-magnetic material for supporting the drive rotor member in a non-contact manner between the opposing surfaces of the pair of fifth portions in the first direction is disposed. The pump according to claim 7 or 8, characterized by the above.

10. The bearing rotor member is An annular bearing magnet; A pair of annular yokes disposed so as to sandwich the bearing magnet in the first direction, and having; The pair of yokes is A pair of fourth portions covering both end faces of the bearing magnet in the first direction and extending in the facing direction with the bearing stator; a pair of fifth portions extending in a direction approaching each other in the first direction from ends of the pair of fourth portions opposite to the bearing stator; a spacer made of a non-magnetic material for supporting the drive rotor member in non-contact with the pair of yokes and the bearing magnet is disposed between opposing surfaces in the first direction on the bearing stator side of the bearing magnet of the pair of fourth portions; a first gap is formed between the fifth portion and the bearing magnet; a second gap is provided between tip portions of the pair of fifth portions facing each other The pump according to claim 7 or 8, characterized in that.

11. a plurality of the bearing stators are arranged along the circumferential direction of the bearing rotor member outside the bearing rotor member in the radial direction, and are respectively opposed to the bearing rotor member in the radial direction The pump according to any one of claims 7 to 10, characterized in that.

12. the drive stator includes an annular drive stator core made of a magnetic material having a plurality of magnetic poles along the circumferential direction of the drive rotor member, facing from the outside in the radial direction of the drive rotor member, and a drive coil wound around a slot of the drive stator core; The pump according to any one of claims 7 to 11, characterized in that.

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