JP2006136062A - Bearingless electromagnetic rotating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearingless electromagnetic rotating device that increases a support force in an axial-conical direction in a bearingless rotating machine that generates torque and a radial directional force by using one electromagnetic machine, and can stably support a rotor. <P>SOLUTION: The bearingless electromagnetic rotating machine stabilizes motor torque and a control force for radial support by making currents flow to a three-phase motor winding 9 and a three-phase support winding 11, and actively performs control. On the other hand, magnetic flux generated by a permanent magnet 35 of a magnetic flux generation part 31 of an axial-conical support passive magnetic bearing 30 flows to an opposite magnetic path 33, and returns to the former permanent magnet 35. By this, support in the axial-conical direction is passive-stabilized. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a bearingless electromagnetic rotating device, and in particular, to a bearingless electromagnetic capable of stable rotor support by increasing the axial and conical supporting force in a bearingless rotating machine that generates torque and radial force in one electromagnetic machine. The present invention relates to a rotating device.

  The bearingless motor is intended to realize a magnetic bearing function and a motor function with one electromagnetic machine (see Non-Patent Document 1). That is, it generates electromagnetic force in the biaxial directions of the radial directions x and y and torque for rotation. In order to perform control in the radial direction, feedback control is performed using an eddy current type or inductance change type displacement sensor in order to grasp the rotor position.

There are two methods for operating a bearingless motor in a completely non-contact manner: a method in which two units are used for five-axis control and a method in which one unit is used for two-axis control. A method of performing the 5-axis control is proposed in Non-Patent Document 2. On the other hand, Non-Patent Document 3 discloses a method of controlling with two axes in the radial direction of x and y.
Tadashi Fukao and Akira Chiba "Bearingless Motor" Journal of the Institute of Electrical Engineers of Japan, Vol. 117, No. 9, pp. 612-615, 1997 Takeshi Fukuda, Tadashi Fukao and Akira Chiba "Prototype of 5-axis control non-contact bearingless motor" Proceedings of Dynamics Symposium on Electromagnetic Forces, No. 940-26 II (D & D '94), D725, pp. 387-392 , 7/14 1994 Ken-ichi MATSUDA etc. "Radial-Type Self-Bearing Motor for Nonpulsatile-Type Artificial Heart" JSME Series C, Vol. 43, No.4, pp. 941-948, 2000

  Such a bearingless motor that controls two axes in the radial direction of x and y generates a magnetic attractive force and supports the rotor. Since it is a suction force, a restoring force is also generated when it is displaced in the axial conical direction. However, there is a problem that the restoring force in the axial / conical direction is weak only by the conventional electromagnetic force in the biaxial directions of x and y.

  The present invention has been made in view of the above-described conventional problems. The bearing-less rotating machine that generates torque and radial force in one electromagnetic machine has increased axial and conical supporting force, and has a stable rotor support. It is an object of the present invention to provide a possible bearingless electromagnetic rotating device.

  Therefore, the present invention (Claim 1) is a bearingless electromagnetic rotating apparatus having a rotor and a stator disposed with a gap from the rotor, and the rotor or the stator side is provided with the A magnetic flux generating means disposed so as to sandwich the gap, generating a magnetic flux by a permanent magnet, and having a magnetic path that is a forward path and a return path from the permanent magnet toward the gap; and on the rotor or stator side The magnetic flux generated by the magnetic flux generating means is disposed so as to sandwich the gap between either one of the other, passes through the forward path, passes the gap and passes through the iron core, and then passes the gap again to pass the magnetic flux generating means. And magnetic path passing means for returning to the return path.

  The magnetic flux passing through the magnetic flux generating means and the magnetic path passing means does not interfere with the magnetic flux in the bearingless motor portion. When the rotor is displaced in the axial conical direction, a large amount of fringing magnetic flux is generated between the magnetic flux generating means and the magnetic path passing means that are separated from each other by a gap, and a large restoring force is obtained by this magnetic flux. Therefore, by providing the bearingless motor with the magnetic flux generating means and the magnetic path passing means via the gap, a greater restoring force can be obtained and stable rotor support is possible.

  Further, the present invention (Claim 2) faces the gap on the rotor side and / or on the stator side between each of the forward path and the return path connecting the magnetic flux generating means and the magnetic path passing means. At least one groove is formed.

  By forming the groove, a large amount of fringing magnetic flux is generated across the gap when the rotor is displaced in the axial conical direction at the convex portion sandwiching the groove. For this reason, a larger restoring force can be obtained.

  Furthermore, the present invention (Claim 3) includes a projecting portion formed with the magnetic path formed and projecting across the groove so as to face the gap, and the projecting portion faces the gap. At least one groove is formed.

  A large amount of fringing magnetic flux is generated across the gap also by the groove formed in the projecting portion. For this reason, a larger restoring force can be obtained.

  Furthermore, the present invention (Claim 4) is characterized in that the magnetic flux generating means and the magnetic path passing means are paired and arranged in the axial direction above and below the center of gravity of the rotor. Restoring force can be obtained at two locations apart from each other across the center of gravity of the rotor.

  This can further stabilize the magnetic bearing control.

  Furthermore, the present invention (Claim 5) is characterized in that the permanent magnets are annularly arranged continuously or divided.

  If divided, permanent magnets can be made more easily.

  Furthermore, the present invention (Claim 6) is characterized in that an excitation magnetic flux of an electric motor and / or radial position control is applied in place of the permanent magnet or so as to have the same magnetic pole as the permanent magnet. .

  The excitation magnetic flux for the electric motor and radial position control is generated by an electromagnet or a permanent magnet. By applying the excitation flux of the electric motor and radial position control to the present invention, the permanent magnet of the magnetic flux generating means can be omitted, or the magnetic flux generated by the permanent magnet of the magnetic flux generating means can be supplemented.

  Further, according to the present invention (Claim 7), the magnetic flux generating means includes a permanent magnet having a magnetic pole in the axial direction, and two iron cores that are connected to each magnetic pole of the permanent magnet and form a magnetic path in the radial direction. The magnetic path passing means includes a tooth portion that faces the iron cores with the gap therebetween, and a back yoke that connects the tooth portions.

  The magnetic flux generating means and the magnetic path passing means can be provided with a simple structure.

  Further, according to the present invention (Claim 8), the magnetic flux generation means includes a permanent magnet having magnetic poles in the axial direction and / or radial direction and / or an excitation magnetic flux of an electric motor, and the magnetic path by the magnetic path passing means is It passes through the rotor and the stator.

  By forming magnetic paths in the rotor and the stator, the axial dimension of the bearingless electromagnetic rotating device can be suppressed.

  Further, the present invention (Claim 9) is a bearingless electromagnetic rotating device having a rotor and a stator disposed with a gap from the rotor, the surface of the rotor and / or the gap of the stator being faced. At least one groove is formed in the portion to be formed.

  By forming a groove in a portion facing the gap between the rotor and the stator, a fringing magnetic flux is generated from the projecting portion sandwiching the groove by an excitation magnetic flux of the electric motor or radial position control. For this reason, even when the rotor is displaced in the axial conical direction, a larger restoring force can be obtained.

  Furthermore, the present invention (Claim 10) is characterized in that the area occupied by the groove is 10 to 60 percent of the area facing the gap of the rotor or the stator.

  When the area occupied by the groove is smaller than 10%, the generation of fringing magnetic flux is small. On the other hand, when the area occupied by the groove is larger than 60%, the torque decreases. For this reason, the area occupied by the groove is set to 10 to 60 percent.

  Furthermore, the present invention (invention 11) is characterized in that the groove is arranged continuously or divided in an annular shape.

  If the groove is divided and arranged in a ring shape, the groove can be formed so as to avoid this, for example, even when a permanent magnet is provided on the rotor or the stator.

  Further, in the present invention (Claim 12), the magnetic path passing means is disposed adjacent to the side of the coil end of the motor winding and / or radial position control winding wound around the stator. It is characterized by that.

  By arranging magnetic path passing means adjacent to the side of the coil end, the bearingless electromagnetic rotating device can be configured in a space-saving manner.

  As described above, according to the present invention, the magnetic flux generating means and the magnetic path passing means are provided. Therefore, when the rotor is displaced in the axial / conical direction, the magnetic flux generating means and the magnetic path passing means separated by a gap. A large amount of fringing magnetic flux is generated between them, and a large restoring force is obtained by this magnetic flux. Therefore, by providing the bearingless motor with the magnetic flux generating means and the magnetic path passing means via the gap, a greater restoring force can be obtained and stable rotor support is possible.

The first embodiment of the present invention will be described below. FIG. 1 is a side view of a bearingless electromagnetic rotating apparatus 10 according to the first embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line AA passing through the center of gravity G in FIG. 1 and 2, a cylindrical shaft 1 is fixed to the base 3 via a case or the like (not shown). A stator 5 having a slot 7 formed on the outer periphery is fixed to the outer periphery of the shaft 1. In this slot 7, a three-phase motor winding 9 for generating a motor torque is arranged on the _outside with 16 poles of N _16u , N _16v and N1 _6w . However, any integer other than 16 may be used, and fractional pitch winding may be applied. It may be a multiphase winding such as 2 or 4 phase. Further, inside the slot 7, a three-phase support winding 11 for generating a radial radial force of N _2u , N _2v and N _2w is disposed. However, the support winding 11 may not have three phases but may have 2, 4, 5, and 6 phases.

  The three-phase motor windings 9 and the three-phase support windings 11 constitute a bearingless motor, and both have coil end portions projecting vertically from the axial thickness of the stator 5. On the outer periphery of the coil end portion, a peripheral wall 23 projects from the stator 5 in the axial direction. An inner peripheral surface 15 a of the rotor 15 faces the outer peripheral portion of the stator 5 with a gap 13 therebetween. The inner peripheral surface 15a has motor / radial support magnets 17 embedded in eight locations in the circumferential direction. The electric motor / radial support magnet 17 is a segment type or a rectangular parallelepiped magnet, and all the insides are magnetized to N poles. The number of these segment-type magnets and the winding method of the motor winding can be changed as the number of poles and the number of slots are changed. The electric motor / radial support magnet 17 may be arranged in an even number such as 2, 4, 6 or the like.

  As shown in FIG. 1, the rotor 15 is formed with a “mountain” -shaped cross section centered on a rotor central annular projecting portion 15 b that is projected inward and has an inner peripheral surface 15 a formed at the top of the head. Yes. The outer periphery of the central annular projecting portion 15b has a rotor side wall 15c extending vertically in the axial direction. Further, the rotor upper side annular projecting portion 15d and the rotor lower side annular are provided at the upper and lower portions of the rotor side wall 15c. The protruding portion 15e is formed in parallel with the central annular protruding portion 15b toward the inside. That is, a groove 19 is formed between the rotor upper annular projecting portion 15d, the rotor side wall 15c and the central annular projecting portion 15b. On the other hand, the rotor lower annular projecting portion 15e, the rotor side wall 15c and the center A groove 21 is formed between the annular projecting portions 15b.

  Magnetic flux generation of the axial / conical supporting passive magnetic bearing 30 whose longitudinal cross-sectional view is shown in FIG. 3 is provided at portions facing the gap 13 of the rotor upper annular projecting portion 15d and the rotor lower annular projecting portion 15e. On the other hand, magnetic path passage portions 33 are arranged on the upper and lower end portions of the peripheral wall 23 so as to face the magnetic flux generating portion 31 of the axial / conical supporting passive magnetic bearing 30 with a gap 13 therebetween. It is installed.

  The magnetic flux generation unit 31 includes an annular permanent magnet 35 and annular iron core portions 37 </ b> A and 37 </ b> B that are fixed to the upper end and the lower end of the annular permanent magnet 35 and are larger than the radial width of the permanent magnet 35 and made of a magnetic material. On the other hand, the magnetic path passage portion 33 is provided to project radially outward from both ends of the back yoke 33C in which the annular core protrusions 33A and 33B facing the annular core portions 37A and 37B are disposed in the axial direction. ing.

Next, the operation of the first embodiment of the present invention will be described.
By passing a current through the three-phase motor winding 9 and the three-phase support winding 11, the motor torque and the control force for supporting in the radial direction are stabilized, and the control is performed actively. On the other hand, the magnetic flux generated by the permanent magnet 35 of the magnetic flux generating portion 31 of the axial / conical supporting passive magnetic bearing 30 flows to the opposing magnetic path passage portion 33 and then returns to the original permanent magnet 35. As a result, the axial and conical support is passively stable.

  Next, when the rotor 15 is displaced in the axial direction (+ z direction) or in the conical direction (+ θ direction), the operation of the axial / conical supporting passive magnetic bearing 30 will be described with reference to FIGS. 4, 5, and 6. It explains using.

  First, FIG. 4 shows an xz cross-sectional view in a state where the rotor 15 is in a steady position with respect to the stator 5 and is not displaced in the axial direction or the conical direction. FIG. 5 shows an xz sectional view when the rotor 15 is displaced in the axial direction (+ z direction) with respect to the stator 5. In FIG. 4, the magnetic flux generated by the magnetic flux generator 31 passes through the gap 13 through a magnetic path as indicated by a dotted line, and flows through the magnetic path passing part 33.

  At this time, a so-called fringing magnetic flux is generated between the projecting portions facing the gap 13 of the annular core portions 37A and 37B and the projecting portions facing the gap 13 of the annular core projections 33A and 33B.

  The fringing magnetic flux functions as a restoring force when the rotor 15 is displaced in the axial conical direction. For example, when the rotor 15 is displaced upward in the axial direction with respect to the stator 5 as shown in FIG. 5 from the normal state of FIG. 4, the end of the magnetic flux generator 31 and the magnetic path passage 33 A magnetic attractive force acts between the ends in a diagonally downward direction indicated by a small arrow in the figure. As a result, a restoring force is exerted on the rotor 15 in the downward direction (−z direction) indicated by a large arrow.

Further, even when the rotor 15 is displaced in the conical direction as shown in FIG. 6, similarly, between the end of the magnetic flux generator 31 and the end of the magnetic path passage 33, in the diagonally downward direction indicated by a small arrow in the figure. Magnetic attraction works. As a result, a restoring force acts on the rotor 15 in a diagonally downward direction indicated by a large arrow. Thus, passive restoration is possible with respect to displacement in the axial conical direction.
Moreover, since the magnetic flux generation part 31 and the magnetic path passage part 33 are separated on the rotor side and the stator side, there is a merit that can be designed independently

  In the first embodiment of the present invention, the magnetic flux generating portion 31 of the axial / conical supporting passive magnetic bearing 30 is provided on the portion facing the gap 13 of the rotor upper annular projecting portion 15d and the rotor lower annular projecting portion 15e. Although it has been described that the magnetic path passage portions 33 are respectively disposed at the upper and lower end portions of the peripheral wall 23, they may be disposed only on one of the upper side and the lower side. For example, even if it is configured only in the upward direction, positive rigidity can be generated in the axial and conical directions.

  Moreover, in 1st Embodiment of this invention, as shown in FIG. 3, the structure where the groove | channel was not formed in the part facing the gap 13 of cyclic | annular core part 37A, 37B and cyclic | annular core protrusion part 33A, 33B was demonstrated. However, as shown in the axial-conical supporting passive magnetic bearing 40 of FIG. 7, grooves 39A, 39B are formed in the annular core portions 37A, 37B, and the grooves 41A, 41B are also formed in the opposed annular core protrusions 33A, 33B. You may make it form. By forming the groove in this way, a fringing magnetic flux is more easily generated through the gap 13.

  Further, the magnetic flux generating part 31 is arranged at the upper and lower end parts of the peripheral wall 23, and the magnetic path passing part 33 is arranged at the part facing the gap 13 of the rotor upper annular projecting part 15d and the rotor lower annular projecting part 15e. You may make it do.

  Furthermore, in the first embodiment of the present invention, the outer rotor type has been exemplified, but the present invention can also be applied to an inner rotor type. In this case, the magnetic flux generation part 31 which consists of a permanent magnet and an iron core is arrange | positioned at an inner side rotor, and a magnetic path passage part is arrange | positioned at the outer periphery stator.

  The magnetic flux generation part 31 and the magnetic path passage part 33 are formed in an annular shape. And generation | occurrence | production of an eddy current etc. can be suppressed by forming in cyclic | annular form in this way. However, it does not necessarily have to be continuous in an annular shape. For example, it may be divided into four parts around the circumference. However, the number of divisions does not have to be 4, and may be an integer such as 2, 3, 5, 6. In fact, it is quite difficult to manufacture a thin cylindrical permanent magnet ring in terms of strength and ease of manufacture, and the price is high. Therefore, by arranging arc-shaped permanent magnets at several locations, the manufacturing can be facilitated and the cost can be reduced. Alternatively, a large number of rectangular parallelepiped permanent magnets can be arranged, and the cost can be further reduced. At this time, it is desirable that the iron core is continuously formed in an annular shape, and plays a role of reducing a change in magnetic flux density caused by the divided permanent magnets. However, depending on the configuration, the iron core may be divided into two parts, three parts, four parts, etc., without using an annular core.

  As shown in FIG. 3, the tooth width (for example, 1.2 mm) of the magnetic path passing portion 33 of the axial / conical supporting passive magnetic bearing 30 is made smaller than the magnet width (for example, 4 mm) of the magnetic flux generating portion 31. The magnetic flux density of the fringing magnetic flux can be improved, while the number of magnetic fluxes passing in the radial direction can be reduced. When the magnetic flux density of the fringing magnetic flux is improved, the positive rigidity in the conical and axial directions can be improved. On the other hand, by reducing the number of magnetic fluxes passing in the radial direction, the negative rigidity added in the radial direction can be reduced. Negative stiffness is generated by an unbalanced suction force and needs to be canceled by the active feedback force of the bearingless motor. For this reason, it is effective for reducing the electromagnetic force of the bearingless motor.

  Further, it is desirable that the tooth width of the magnetic path passage portion 33 be 50% or less of the magnet width of the magnetic flux generation portion 31. Also, the magnetic flux can be effectively generated by designing the width of the back yoke 33C of the magnetic path passage portion 33 to be the same as the tooth width or about plus or minus 50%. It is desirable that the height of the magnet of the magnetic flux generator 31 is designed to be 1.2 times or more of the tooth width.

  Further, the entire width of the magnetic path passing portion 33 is thinner than the width of the magnetic flux generating portion 31. For this reason, when the magnetic path passage portion 33 is disposed on the stator 5 side as shown in FIG. 1, the magnetic path passage portion 33 can be disposed in parallel with the coil end in the axial direction, and the space can be configured. . The overall length in the radial direction can be short. If there is no need for space saving, the magnetic path passage portion 33 may be arranged on the rotor 55 side.

  Further, in FIG. 1, the position of the axial / conical supporting passive magnetic bearing 30 decreases as the conical rigidity decreases as it moves away from the horizontal line passing through the center of gravity G in the axial direction upward and downward. For this reason, it is advantageous to save the space and arrange the axial / conical supporting passive magnetic bearing 30 near the coil end.

Next, a second embodiment of the present invention will be described.
The second embodiment of the present invention has a part of the structure of the axial and conical supporting passive magnetic bearings 30 and 40, and has the same function as the axial and conical supporting passive magnetic bearings 30 and 40 of the first embodiment of the present invention. It is a thing with.

  FIG. 8 shows a configuration diagram of the second embodiment of the present invention. In FIG. 8, grooves 53 </ b> A and 53 </ b> B are formed circumferentially on the outer peripheral upper end 51 </ b> A and lower end 51 </ b> B of the stator 50. An annular projecting portion 57A is disposed on the upper portion of the groove 53A toward the outside, while an annular projecting portion 57B is disposed on the lower portion of the groove 53B. Similarly, grooves 59A and 59B are formed on the rotor 55 side facing the grooves 53A and 53B, respectively. An annular projecting portion 61A is disposed on the upper side of the groove 59A while an annular projecting portion 61B is disposed on the lower portion of the groove 59B.

  Here, a permanent magnet 63 is disposed at any location indicated by A, B, and C in FIG. 8 so as to be in the same direction as the magnetic flux of the electric motor. At the point A, the magnetic flux of the motor is directed in the axial direction, so the magnetic poles are aligned so that they are in the same axial direction. On the other hand, at the locations B and C, the magnetic fluxes of the electric motor are oriented in the radial direction, so the magnetic poles are aligned so as to be the same radial direction.

  That is, in the configuration of FIG. 8, the upper side in the configuration of the first embodiment of the present invention leaves the annular core portion 37B of the magnetic flux generator 31 and the annular core protrusion 33B of the magnetic path passage portion 33, and the permanent magnet 35 and The annular core portion 37A, the back yoke 33C and the annular core protrusion 33A are omitted. Similarly, the annular core 37A of the magnetic flux generator 31 and the annular core protrusion 33A of the magnetic path passing portion 33 are also left, and the permanent magnet 35 and the annular core 37B, the back yoke 33C and the annular core protrusion are also left. 33B is omitted.

Next, the operation of the second embodiment of the present invention will be described.
The magnetic flux generated by the permanent magnet 63 passes through the annular projecting portion 57A across the gap 13 as shown by the dotted line D on the upper side in FIG. 8, and passes through the magnetic path surrounding the groove 53A and the groove 59A. The permanent magnet 63 is separately provided on the lower side in FIG. 8, and passes through a magnetic path surrounded by a dotted line E by the lower permanent magnet 63. That is, the axial conical supporting passive magnetic bearings 30 and 40 according to the first embodiment of the present invention have magnetic paths formed above the grooves 19, whereas in the second embodiment of the present invention, the grooves 53 and It differs in that a magnetic path is formed in the stator and rotor portion on the center of gravity G side through the magnetic path surrounding the groove 59 from the first embodiment of the present invention.

Since a fringing magnetic flux exists around the end portion of the permanent magnet 63 and the end portion of the annular projecting portion 57A via the gap 13, the displacement of the first embodiment of the present invention against axial and conical displacement is the same as that of the first embodiment of the present invention. Similarly, it functions as a restoring force. For this reason, magnetic bearing control is stabilized.
Note that only one of the magnetic path of the dotted line D and the magnetic path of the dotted line E may be formed.

  Further, in the continuous ball bearingless motor, the electric motor / radial support magnet 17 attached to the rotor 55 can automatically generate the magnetic flux in the axial direction, and there is no need to separately provide a permanent magnet. Can be Of course, in the homopolar and hybrid type bearingless motors, the fringing magnetic flux is generated in the annular projecting portion 57A and the like by effectively using the field magnetic flux generating mechanism without separately providing a permanent magnet. As with the first embodiment of the present invention, it can function as a restoring force with respect to the displacement in the conical direction. In this case, a permanent magnet or an electromagnet that generates a homopolar magnetic flux may be disposed in either the stator 50 or the rotor 55.

Next, a third embodiment of the present invention will be described.
In the third embodiment of the present invention, an electric motor or radial position control magnetic flux is used in place of the axial and conical supporting passive magnetic bearings 30 and 40.

  FIG. 9 shows a configuration diagram of the third embodiment of the present invention. The third embodiment of the present invention is an example using a surface-mounted permanent magnet motor. In FIG. 9, there is no equivalent to the axial / conical supporting passive magnetic bearings 30 and 40. On the inner peripheral surface of the cylindrical rotor 65, an annular permanent magnet 71 whose inner side is magnetized with an N pole is fixed. The permanent magnet 71 is configured by being stacked in a plurality of stages in the axial direction. The permanent magnet 71 has a different radial length for each stage, and the permanent magnet 71A has a longer radial length in order from the top of FIG. 9, and the next permanent magnet 71B has a shorter radial length. Thereafter, similarly, the permanent magnet 71C has a long radial length, and the next permanent magnet 71D has a short radial length. As a result, a groove 69 is formed in a space surrounded by the permanent magnet 71A, the permanent magnet 71B, and the permanent magnet 71C. Similarly, a plurality of grooves are formed in the axial direction. A toothed portion 81 is formed in the protruding portion of the permanent magnet 71A and the permanent magnet 71C.

  A plurality of grooves 72 are formed on the outer periphery of the stator 60 so as to face the grooves 69, while teeth 74 are provided on the outer periphery of the stator 60 facing the permanent magnets 71A and 71C. Has been. For example, the height of the tooth portion 74 coincides with the height of one laminated steel plate used for the stator 60.

Next, the operation of the third embodiment of the present invention will be described.
Originally, even in a conventional bearingless rotating machine in which no grooves are provided on the outer periphery of the rotor or the stator, fringing magnetic flux is generated at both axial ends (the uppermost end and the lowermost end). Therefore, even if a groove is not provided, in principle, it tends to be stable although it is weak in the conical and thrust directions. However, when the shaft length is long, the method of the present invention is effective when larger conical and thrust rigidity is required. That is, in the third embodiment of the present invention, the groove 72 is formed on the outer periphery of the stator 60 and the groove 69 is formed on the inner periphery of the rotor 65, so that the tooth portion 74 and the tooth portion 81 are axially arranged. A large amount of fringing magnetic flux can be generated. For this reason, it can be made to function as a restoring force similarly to 1st Embodiment of this invention with respect to the displacement of an axial and a conical direction.

  However, if the groove is formed over the entire circumference, the torque of the motor itself may be reduced. Therefore, the grooves may be arranged in a limited manner at four places or a plurality of places in the circumferential direction. As a result, a reduction in torque due to the formation of the groove can be reduced.

  In addition, for example, in the case of a continuous pole type, a groove may be formed only in the iron core portion for cost reduction. Then, the permanent magnet can use the same thing as before forming the groove. Originally, a laminated steel plate is often used for the iron core of the rotor and the stator. Therefore, in order to form the groove, it is possible to prepare two sheets and adjust the thickness to be overlapped.

  As the number of grooves increases, the stability of the thrust conical can be improved. Therefore, it is effective to form a plurality or a plurality of grooves. In order to generate a fringing magnetic flux, it is desirable to form a groove having the same length as the gap 13 or a half or more of the length of the gap 13. Further, when the groove area on the gap surface increases, the motor torque is greatly reduced, which becomes a problem. Therefore, it is desirable that the groove area with respect to the gap surface is 10% to 60%.

Next, another aspect of this embodiment is shown in FIG.
In FIG. 10, the cross section of the groove is rectangular in the third embodiment, but in this different aspect, a step is provided in the cross section of the groove. In general, the thickness of the laminated steel sheet used is 0.3 to 0.5 mm, but the groove 89 formed in the rotor 85 in FIG. 10 is formed by stacking three laminated steel sheets. . That is, the first and third laminated steel sheets have the same radial length, while the second laminated steel sheet has a shorter radial length than the first and third stages. As a result, a groove 89 having two steps is formed, while the tooth portion 91 protrudes inward. Similarly, a groove 83 having two steps is formed on the side of the stator 80 facing the groove 89, while a tooth portion 82 projects outward.

  In such a configuration, since the groove 83 and the groove 89 have two steps, a fringing magnetic flux between the tooth part 82 and the tooth part 91 is generated more than in the case of the rectangular groove of the third embodiment. . For this reason, it can be made to function as a restoring force larger than the case of 3rd Embodiment of this invention with respect to the displacement of an axial and a conical direction.

  The cross-sectional shapes of the groove 83 and the groove 89 are not limited to two steps, and may have a step such as three steps and a shape closer to a triangular shape. Thus, if a continuous triangular groove is formed, more fringing magnetic flux is generated between the tooth part 82 and the tooth part 91 than when there are two or three steps. To do. In addition, the tooth part 82 and the tooth part 91 are more semi-circular than the rectangular cross section, and more fringing magnetic flux between the tooth part 82 and the tooth part 91 is generated. It is more desirable to stabilize the displacement.

Next, still another aspect of the third embodiment of the present invention will be described.
This aspect is a case where the groove described in the third embodiment is applied to a disk-type bearingless motor.

  As shown in FIG. 11, the disk-type bearingless motor 100 has a disk-shaped rotor 110 that is levitated between a stator 120A and a stator 120B with a predetermined gap 111A and gap 111B. The disk-type bearingless motor 100 is actively stable in the conical / axial direction, but passively stable in the radial direction. If the rigidity in the radial direction is improved, the critical speed is increased at a higher speed, and stabilization is achieved. Although it is possible to pass the dangerous speed by tilting the rotor 110, it is desirable that the dangerous speed is higher than the driving speed.

  Therefore, as in the third embodiment, an annular groove 121 is formed in a portion facing the gap 111A of the stator 120A, while a groove 123 is formed in a portion facing the gap 111A of the rotor 110 facing the groove 121. Grooves are similarly formed on the rotor 110 and the stator 120B side facing the gap 111B. Thereby, the rigidity in the radial direction can be improved.

  The annular groove 121 may be disposed in a double or triple manner, or may be divided in the circumferential direction. The cross-sectional shape of the groove may be triangular. A groove may be provided only on one side of the gap 111A or the gap 111B.

  The number of poles / slots of the bearingless motor is 16 poles / 24 slots as described in the first embodiment, and all of the eight electric motors / radial support magnets 17 are magnetized with N poles on the inside. FIG. 3 shows the dimensions of the axial magnetic conical passive magnetic bearing 40. The magnet width is 4 mm, the magnet height is 5 mm, the tooth width is 1.2 mm, and the back yoke width is 1.2 mm. FIG. 12 shows the restoring force against the axial displacement at this time, and FIG. 13 shows the rigidity.

  As an application example of the present invention, this bearingless electromagnetic rotating device is used as a generator such as a micro gas turbine, a flywheel motor generator, a pump, a blower, a compressor drive, an air conditioner, a household appliance, a computer device drive, an automobile turbo. It can be applied to generator motors, bioreactors, semiconductor manufacturing equipment, motors in vacuum containers, motors in special gases, liquids, and the like.

The side view of the bearingless electromagnetic rotating apparatus which is 1st Embodiment of this invention. AA arrow line cross section passing through the center of gravity G in FIG. Longitudinal section of passive magnetic bearing for axial and conical support Diagram explaining the action of passive magnetic bearing for axial and conical support (steady position) Xz sectional view when the rotor is displaced in the axial direction (+ z direction) with respect to the stator Xz sectional view when the rotor is displaced in the conical direction (+ θ direction) with respect to the stator Another example of passive magnetic bearing for axial and conical support Configuration diagram of second embodiment of the present invention The block diagram of 3rd Embodiment of this invention Same aspect Same aspect Diagram showing restoring force against axial displacement Diagram showing stiffness against axial displacement

Explanation of symbols

1 Shaft 5, 50, 60, 80, 120 Stator 9 Three-phase motor winding 10 Bearingless electromagnetic rotating device 11 Three-phase support winding 13, 111 Gap 15, 55, 65, 85, 110 Rotor 23 Perimeter wall 17 Electric motor / radial Supporting magnets 19, 21, 39, 41, 53, 59, 69, 72, 83, 89, 121, 123 Grooves 30, 40 Axial-conical supporting passive magnetic bearings 31 Magnetic flux generator 33 Magnetic path passage 33C Back yoke 35, 63, 71 Permanent magnets 74, 81, 82, 91 Teeth 100 Disc type bearingless motor

Claims (12)

A rotor,
A bearingless electromagnetic rotating device having a stator disposed with a gap with respect to the rotor,
A magnetic path that is disposed so as to sandwich the gap between either the rotor or the stator, generates a magnetic flux by a permanent magnet, and forms a forward path and a return path from the permanent magnet toward the gap. Magnetic flux generating means;
The magnetic flux generated by the magnetic flux generating means is disposed so as to sandwich the gap between the other of the rotor and the stator side, passes through the forward path, passes through the iron core, and then returns to the gap. And a magnetic path passing means for returning to the return path of the magnetic flux generating means.   At least one groove facing the gap is formed on the rotor side and / or the stator side between each of the forward path and the return path connecting the magnetic flux generating means and the magnetic path passing means. The bearingless electromagnetic rotating device according to claim 1. The magnetic path is formed, and includes a projecting portion projecting across the groove facing the gap,
The bearingless electromagnetic rotating device according to claim 2, wherein at least one groove facing the gap is formed in the projecting portion.   4. The bearingless electromagnetic rotating device according to claim 1, wherein said magnetic flux generating means and said magnetic path passing means are arranged in a vertical direction sandwiching the center of gravity of said rotor as a pair. .   The bearingless electromagnetic rotating device according to any one of claims 1 to 4, wherein the permanent magnet is annularly arranged continuously or divided.   6. The excitation magnetic flux of an electric motor and / or radial position control is applied in place of the permanent magnet or so as to have the same magnetic pole as that of the permanent magnet. The bearingless electromagnetic rotating device described. The magnetic flux generation means includes a permanent magnet having a magnetic pole in the axial direction;
Two iron cores connected to each magnetic pole of the permanent magnet and forming a magnetic path in the radial direction, and the magnetic path passing means includes teeth that oppose each iron core with the gap therebetween;
The bearingless electromagnetic rotating apparatus according to claim 1, further comprising a back yoke that connects the tooth portions. The magnetic flux generation means includes a permanent magnet having magnetic poles in the axial direction and / or radial direction and / or an excitation magnetic flux of an electric motor,
The bearingless electromagnetic rotating device according to claim 1, wherein a magnetic path formed by the magnetic path passing unit passes through the rotor and the stator. A rotor,
A bearingless electromagnetic rotating device having a stator disposed with a gap with respect to the rotor,
A bearingless electromagnetic rotating device, wherein at least one groove is formed in a portion of the rotor and / or the stator facing the gap.   The bearingless electromagnetic rotating device according to claim 9, wherein an area occupied by the groove is 10 to 60% of an area facing the gap of the rotor or the stator.   The bearing-less electromagnetic rotating device according to any one of claims 2 to 10, wherein the groove is annularly arranged continuously or divided.   The magnetic path passing means is disposed adjacent to a side of a coil end of an electric motor winding and / or radial position control winding wound around the stator. The bearingless electromagnetic rotating apparatus of any one of Claims.

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