JPS5937323A - Magnetic bearing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a magnetic bearing device, and more particularly to a magnetic bearing device that is compact and exhibits good bearing characteristics.

[Background technology of the invention and its problems]

2. Description of the Related Art Magnetic bearing devices are conventionally known as bearings that support a rotating body in a completely non-contact manner. This magnetic bearing device is often used to support rotating bodies whose rotational characteristics are easily influenced by the frictional force of the bearing, whose lifespan must be guaranteed semi-permanently without inspection, and rotating bodies used in vacuum. It is being

Incidentally, such a magnetic bearing device generally supports the bearing by utilizing magnetic attractive force, and a radial bearing portion and an axial bearing portion constitute one bearing. Usually, the radial bearing is configured as a passive type using a permanent magnet, and the axial bearing is configured as an active type using a control coil.

However, the conventional bearing device of this type has an opening/closing ratio of 54%.
As typified by the one shown in Japanese Patent No. 49440, the radial support portion and the axial support portion are provided completely independently. For this reason, there are many parts,
Since it is difficult to manufacture and assemble these parts with high precision, the reliability of the device is poor, and the overall size of the device becomes large.

[Purpose of the invention]

The present invention was made in view of the above circumstances, and its purpose is to realize a passive radial bearing and an active axial bearing while reducing the number of parts. Therefore, it is an object of the present invention to provide a magnetic bearing device that can improve the reliability of the device and downsize the entire device.

[Summary of the invention]

According to the invention, a central member is provided at the center of rotation, which is part of the magnetic flux path. First and fifth-second magnetic bearing elements are fixed at two locations in the axial direction on the outer periphery of the central member. Further, a magnetic gap is provided between the first and second magnetic bearing elements, and the magnetic attraction force generated between the first and second magnetic bearing elements causes the first and second magnetic bearing elements to form a magnetic gap. Third and fourth magnetic bearing elements are disposed substantially axially coupled to each other in a completely non-contacting relationship with the second magnetic bearing element. Each magnetic bearing element is composed of an inner magnetic pole ring, an outer magnetic pole ring, and a radially magnetized permanent magnet ring mounted between both magnetic pole rings. That is, the above arrangement constitutes two axially opposed magnetic bearing portions of the so-called permanent magnet yoke type. In the present invention, in particular, the inner magnetic pole rings of the third and fourth magnetic bearing elements are magnetically connected to each other, and the inner magnetic pole rings in the magnetic bearing portion of one of the permanent magnet yoke opposing types described above are connected to each other. The magnetization polarity of each permanent magnet ring 6- is set so that the direction of the magnetic field is different from the direction of the magnetic field between the inner magnetic pole rings in the magnetic bearing section of the other permanent magnet yoke facing type. An axial control coil is mounted on the outer periphery of the central member located between the second magnetic bearing elements.

〔Effect of the invention〕

In the double configuration, a passive radial bearing can be realized by means of two magnetic bearings of the so-called permanent magnet yoke type. When the coil is energized, the magnetic flux generated by this coil is transmitted from the center to the inner magnetic pole ringle magnetic gap of the M1 magnetic bearing element, to the inner magnetic pole ringle magnetic gap of the third and fourth magnetic bearing elements, to the second magnetic bearing element. The inner magnetic pole ring of the magnetic bearing element passes in the path of the central member. The directions of the magnetic field in the magnetic gap between the two inner magnetic pole rings when the coil is energized are set in different directions as described above, so when the magnetic flux generated in the coil passes through the above path, one side The magnetic flux will increase in one magnetic gap, and the magnetic flux will decrease in the other magnetic gap. Therefore, in the magnetic gap part where the magnetic flux has increased, the magnetic attractive force between the stationary side and the rotating side increases, and in the magnetic gap part where the magnetic flux has decreased, the magnetic attractive force between the stationary side and the rotating side increases. This allows the rotating side to move to a stable position in the axial direction. That is, in the present invention, it is possible to realize an active axial support by sharing a part of the passive radial support. Since a portion of both bearings are shared in this way, the number of parts can be significantly reduced compared to conventional devices, which makes manufacturing and assembly easier, providing a highly adaptable product. can. Additionally, due to the structure, the coil for axial control is designed to fit within the configuration space of the radial bearing.
As a result, the overall size can be reduced. In addition, since a passive radial support section is formed by the magnetic bearing section facing the permanent magnet yoke, the stiffness Kr in the radial direction can be increased due to the magnetic flux concentration effect on the yoke section. The circumferential rigidity θ can also be increased. That is, assuming that the diameter of the bearing is B, the axial length is B1, and the unbalanced stiffness in the axial direction is Ku, then Kθ is generally Kθ= −Kr (B2−” ・
-to-'-A2) -...(1)4 2
Denoted by Kr. As can be seen from equation (1), as Kr becomes thicker, θ also becomes larger. Therefore, it is possible to exhibit highly stable bearing performance.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a magnetic bearing device according to an embodiment of the present invention, in which a flywheel is supported.

That is, numeral 1 in the figure has nine paces made of, for example, a non-magnetic material, a magnetic bearing device 2 is supported by the pace 1, and a flywheel 3 is supported by the rotating portion of the magnetic bearing device 20.

The magnetic bearing device 2 is roughly divided into a central member 21 which also serves as a support column to which one end is fixed to a base IK, and this central member 2.
Two stationary magnetic support elements 22a are fixed at two locations in the axial direction on the outer periphery of the stationary magnetic support element 22a.

21b and these two stationary side magnetic bearing elements 9-22m, 22b, there is a magnetic gap f;
13a, 2:Ib are provided, and the two stationary side magnetic bearing elements 22h, 22b are arranged in a completely non-contact supported relationship by the magnetic attraction force generated between them, and are connected to each other in the axial direction. one rotating side magnetic bearing element 24*,
24b, and a coil 25 for axial control mounted on the outer periphery of the central member 21.

The central member 2 is made of a soft magnetic material having high magnetic permeability and high saturation magnetic flux density characteristics, such as electromagnetic soft iron or silicon steel, and has large diameter portions 31* and 31b formed at both ends thereof. ing. The stationary magnetic support elements 22h and 22b are fixed to the outer circumferences of the large diameter portions 31* and 31b, respectively.

The stationary side magnetic bearing elements 22* and J12b are arranged to face each other in the axial direction, and each has an inner magnetic pole ring Jj made of the same soft magnetic material as the material forming the central member.
a, 32b, outer magnetic pole rings ss*, ssb,
It is comprised of permanent magnet rings 34h and 34b that are mounted between these two rings 10- and are magnetized in the radial direction as shown by the polarities shown in the figure.

On the other hand, the two rotating side magnetic bearing elements 23a.

In this example, 28b is configured to share one element], and two stationary side magnetic bearing elements JJa, JJ
Similarly to b, the inner magnetic pole ring 35 and the outer magnetic pole ring 3
6, and a permanent magnet ring 37 that is installed between these two rings and is magnetized in the radial direction so that the polarity is opposite to that of the permanent magnet rings 34 and 34b on the stationary side, as shown in the illustrated polarity. has been done. The flywheel 3 is fixed to the outer magnetic pole ring 36jpC.

In addition, 38 in the figure applies rotational force to the flywheel 3 at tJ −
1f indicates the rotor of the fermentation motor or brushless motor 39, and 40 indicates the stator of the motor. Furthermore, 41 indicates a sensor that detects the displacement of the flywheel 3 in the axial direction, and 4ji1.43 indicates a ball bearing that mechanically supports the flywheel 3 and the rotating part of the pawl only in an emergency or the like. Then, only when displacement is detected by the sensor 41, a control device (not shown) supplies a current to the coil 25 corresponding to the direction and magnitude of the axial displacement (speed, acceleration).

With this configuration, magnetic flux passes between the stationary magnetic bearing element 221 and the rotating magnetic bearing element 24a axially opposed thereto, as shown by the dashed arrow 51 in FIG. Both of them constitute one permanent magnet yoke-opposed magnetic bearing part, and also between the stationary side magnetic bearing element 22b and the rotating side magnetic bearing element 24b axially opposed thereto. Since the magnetic flux passes through the magnetic flux as shown by the broken line arrow 52 in FIG. 2, the two constitute one magnetic bearing section facing the permanent magnet yoke. Therefore, the two rotating side magnetic bearing elements j4ajJ4b% are
The rotating parts t and b are supported in a non-contact manner in a radially passive manner. That is, the two magnetic bearing sections described above constitute a passive radial bearing section. If the rotating part is displaced in the axial direction for some reason, this displacement is detected by the sensor 41, and based on this detection output, the above-mentioned control device determines the axial displacement (velocity).

The current corresponding to the magnitude and direction of
Supply to 5. The magnetic flux generated by the energization of the coil 25 is transmitted from the central member 21 to the inner magnetic pole ring JJa to the magnetic gap JJa to the inner magnetic pole ring 35 to the magnetic gear f: 18b to the inner magnetic pole puffer as shown by the two-dot chain line in FIG. 32b
- Passes along the route of the central member 21. Now the rotating part! Assuming that the setting is such that the magnetic flux generated in the coil 25 passes through the inside of the inner magnetic pole ring 35 in the direction shown by the arrow 5S when the coil 25 is displaced upward in FIG. In the magnetic gap between the inner magnetic pole ring 35 and sxb, the magnetic flux decreases and the magnetic attractive force between the two rings decreases, and in the magnetic gap 13- between the inner magnetic pole ring 35 and sxb, the magnetic flux increases and the magnetic attraction between the two rings decreases. magnetic attraction increases. Therefore, the rotating portion moves downward in FIG. 2 to a stable position. Therefore, the rotating part is supported in an axially active manner in a non-contact manner. That is, the central member 21, the inner pole rings 32m, 35.32b and the coil 25 form an active axial bearing.
Become.

In this case, a part of the passive radial bearing is used to form the active axial bearing, so
Compared to a system in which both bearing parts are provided independently, the overall structure is not only simplified, but also the number of parts can be significantly reduced, which improves reliability and reduces the overall number of parts. Can be modeled. In addition, since it uses a magnetic bearing section that faces the permanent magnet yoke, the rigidity in the radial direction can be increased.
This makes it possible to increase the rigidity around the orthogonal axes, resulting in the above-mentioned effects.

Note that the present invention is not limited to the embodiments described above. For example, as shown in FIG. 3, by making the portions P near the magnetic gaps of the outer magnetic pole rings 33*, 33b, and 36 of the magnetic bearings 11g22a, 22b, 24m, and 24b thinner, each inner magnetic pole ring 32h
, 32b, 35 to realize a much higher magnetic flux density and make it easier to saturate.
/Kr may be made smaller to further increase θ for the stiffness around the orthogonal axes.Alternatively, as shown in FIG.
Each magnetic bearing element 22a, 22b, 24e+, 24
The magnetic flux distribution state may be changed by providing unevenness Q on the surfaces of the outer magnetic pole rings 33h, 33b, and 36 facing the magnetic gap, thereby further increasing the radial rigidity Kr. Also, as shown in FIG. 5, each magnetic bearing element 22a.

A conductive plate R may be placed at the magnetic gap side position of 22b, 24h, and 24b, and this may function as an eddy current type vibration damper, as shown in Fig. 6.
Each permanent magnet ring 34a.

The magnetic flux may be concentrated on each magnetic pole ring by retracting the end faces of 34b and 31 located on the magnetic gap side. Furthermore, as shown in FIG. 7, a supported rotating body S made of a non-magnetic material may be connected to the inner magnetic pole ring 35. In this case, the rotary side permanent magnet ring is axially separated by the supported rotating body S into 37a and J7b, and the outer magnetic pole ring is also axially separated into 36m and 36b. Further, in the embodiment shown in FIG. 1, the flywheel is supported by the magnetic bearing device according to the present invention.
Of course, it is possible to support not only the flywheel but also various rotating bodies. Furthermore, on each side mentioned above, there are six central members 21 and magnetic bearing elements 22m, 22 connected thereto.
b is the stationary side, but by providing a gap between the central member 21 and the coil 25, the central member 21 and the magnetic support element 22a.

22b can also be on the rotating side.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a flywheel device incorporating a magnetic bearing device according to an embodiment of the present invention, and FIG. 2 is a schematic diagram of one side of the flywheel device with the axis line as a boundary for explaining the action of the magnetic bearing device. , and FIGS. 3 to 7 are longitudinal cross-sectional views of one side of the magnetic bearing device according to different embodiments of the present invention, taken along the axial center line. 2 J-...Central shrine, 22*j22ba24*. 24b... Magnetic bearing element, 25... Control coil, J J a , 3 j b , J 5 =... Inner magnetic pole ring *3 Sh&J 3b, 36.36h, 36
b...Outer magnetic pole ring s 34ha34ba31a3
1*m37b...Permanent magnet ring. Applicant's agent Patent attorney Takehiko Suzue 171 Figure 7-117-

Claims (1)

[Claims] (1,) A central member that can form part of the magnetic flux path, and a central member fixed at two locations in the axial direction on the outer circumference of the central member, each magnetically connected to the central member. first and second magnetic bearing elements comprising an inner magnetic pole ring, an outer magnetic pole ring disposed outside of the inner magnetic pole ring, and a radially magnetized permanent magnet ring installed between the two rings; and a second magnetic bearing element with a magnetic gap therebetween and arranged in a state of being substantially axially connected to each other, and between the first and second magnetic bearing elements. The generated magnetic attraction force holds the first and second magnetic bearing elements in a completely non-contact manner, and each of the inner magnetic pole ring, the outer magnetic pole ring disposed outside of the inner magnetic pole ring, and the outer magnetic pole ring are mounted between the two rings. third and fourth magnetic bearing elements comprising permanent magnet rings with radial N magnetism, and a control mounted on an outer periphery of the central member located between the first and second magnetic bearing elements; the inner magnetic pole rings of the third and fourth magnetic bearing elements are magnetically connected to each other, and the inner magnetic pole rings of the third and fourth magnetic bearing elements and the first and first A magnetic bearing device characterized in that the magnetization polarity of each of the permanent magnet rings is set so that the directions of the magnetic fields in two magnetic gaps existing between the inner magnetic pole rings of the two magnetic bearing elements are different from each other. . (2) The magnetic bearing device according to claim 1, wherein the permanent magnet rings of the third and fourth magnetic bearing elements share one permanent magnet ring. (3) The outer magnetic pole rings of the first and second magnetic bearing elements and the outer magnetic pole rings of the third and fourth magnetic bearing elements that are adjacent to each other via the magnetic gap are the inner sides of each of the magnetic bearing elements. 3. The magnetic bearing device according to claim 1, wherein the magnetic bearing device is configured to realize a magnetic flux density higher than the magnetic poles S/G and exhibit a magnetic flux saturation state. (4) The outer magnetic pole rings of the first and second magnetic bearing elements and the outer magnetic pole rings of the third and fourth magnetic bearing elements, which are adjacent to each other via the magnetic gap, pass through the magnetic gear horn. A patent claim characterized in that the relative positions of the opposing outer magnetic pole rings are set in an end face shape that can realize a magnetic flux distribution that effectively acts as a radial restoring force when the opposing outer magnetic pole rings return to the center in the radial direction with respect to the magnetic flux. The magnetic bearing device according to item 1 or 2. (5) the first and second magnetic bearing elements and the third;
The magnetic bearing element belonging to at least one of the fourth magnetic bearing elements is characterized in that an electromagnetic vibration damping element is added at a position on the side of the magnetic ear. Magnetic bearing device 0 according to any one of item 4