JP2002081445A - Repulsion-type magnetic levitation bearing, manufacturing method thereof, and light-deflecting scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily miniaturize a repulsion-type magnetic levitation bearing by weakening the adjusting sensitivity of the magnetic force by adjusting the size of a rotor magnet and a stator magnet, and easily adjusting the magnetic force. SOLUTION: This repulsion-type magnetic levitation bearing is designed with the size of the stator magnet 5 as a parameter for adjusting the component of the repulsion between the stator magnet 5 and the rotor magnet 3 in the axial direction of the rotation of the rotor 2, and the quantity of the stator magnet 5 is set to be more than that of the rotor magnet 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rotor provided with a rotor magnet having a vertical rotation axis direction, and a stator magnet provided on a stator so as to face the rotor magnet.
The present invention relates to a repulsion type magnetic levitation bearing in which a rotor is levitated with respect to a stator by the repulsive force of both magnets to support a rotating shaft of the rotor, a manufacturing method thereof, and an optical deflection scanning device.

[0002]

2. Description of the Related Art In electrophotography, an optical deflection scanning apparatus for forming an electrostatic latent image on a photosensitive member by deflecting and scanning a laser beam in one direction is used. In a laser scanning display device, an image is formed by scanning a beam on a screen by combining two light deflection scanning devices whose deflection directions are orthogonal to each other.

As a bearing used for rotating a polygon mirror in such an optical deflection scanning device, a repulsion type magnetic levitation bearing having a simple device configuration is known (Japanese Patent Application Laid-Open No. HEI 9-163568).
No. 11-2777). In this repulsion type magnetic levitation bearing,
There are a so-called horizontal type in which the rotation axis is perpendicular to the vertical direction, and a so-called vertical type in which the rotation axis is in the vertical direction.

The structure of a vertical repulsion type magnetic levitation bearing is as follows. That is, the rotor is disposed inside and the stator is disposed outside, both of which are coaxial with the rotation axis. The rotor has a cylindrical shape centered on the rotating shaft, and the stator has a hollow cylindrical shape coaxial with the rotating shaft. A gap region is provided between the outer peripheral surface of the rotor and the inner peripheral surface of the stator, and the outer peripheral surface of the rotor does not contact the inner peripheral surface of the stator. The rotor and the stator are provided with permanent magnets that are coaxial with the rotation axis. The permanent magnet on the rotor side (hereinafter referred to as rotor magnet) and the permanent magnet on the stator side (hereinafter referred to as stator magnet) are arranged such that the outer peripheral surface of the rotor magnet and a part of the inner peripheral surface of the stator magnet face each other. ing. Hereinafter, a pair of the rotor magnet and the stator magnet is referred to as a permanent magnet pair. This pair of permanent magnets is one above and below the center point of the shaft.
There are two sets in total. The rotor and stator magnets are
Each is magnetized and oriented in the axial direction.

[0005]

If the repulsion type magnetic levitation bearing can be applied to a laser beam printer or a laser scanning display device, optical scanning can be performed at high speed, and writing speed can be increased. Thus, an effect of improving the image quality of the display can be expected. However,
Conventionally manufactured repulsion type magnetic levitation bearings are relatively large (shaft length is about several tens of cm). In order to apply the repulsion type magnetic levitation bearing to a laser beam printer or a laser scanning display device, it is necessary to compare with the conventional type. Want a compact device configuration.

Therefore, for example, an attempt is made to apply a repulsion type magnetic levitation bearing using a permanent magnet to a bearing of an optical deflection scanning device for a laser beam printer or a laser scanning display device in which the axis of a rotating shaft is about several cm. Then, the following problem occurs.

First, when the size of the bearing is reduced, the weight of the bearing is reduced. The repulsive force between the rotor magnet and the stator magnet can be divided into a radial component of the rotating shaft (hereinafter referred to as r-direction repulsive force) and a rotating shaft direction component (hereinafter referred to as Z-directional repulsive force). Then, it is necessary to balance the Z direction repulsion with the weight of the bearing. If the weight of the bearing is reduced, the repulsion in the Z direction must also be reduced. However, if the magnetic force of the magnet is reduced, the repulsion in the r direction is also reduced. When the r-direction repulsion force is weak, a problem occurs that the rotor and the stator are likely to come into contact with each other. Therefore, a means for adjusting the r-direction repulsion and the z-direction repulsion is required. If the repulsive force in the Z direction is too strong, the rotating shaft is strongly pushed toward the support, and the rotor does not rotate. On the other hand, if the repulsive force in the z direction is too weak, the rotating shaft tends to separate from the support, and the shaft cannot be stabilized in this state.

The following can be said from the viewpoint of easy adjustment of magnetic force balance. That is, when a certain adjustment parameter for adjusting the magnetic force of the rotor magnet and the stator magnet is considered, it is difficult to adjust the magnetic force if the change in the repulsive force between the rotor magnet and the stator magnet relative to the change in the parameter value is large. Becomes In other words, it is desired to easily adjust the magnetic force balance by finding an adjustment parameter with a low adjustment sensitivity. There are many tuning parameters,
Among them, the weight, diameter, and length of the rotor are important parameters. However, when the above-described repulsion type magnetic levitation bearing is applied to an optical deflection scanning device using a polygon mirror, the shape, size, and weight required for the polygon mirror are determined in advance by the specifications of the applied device. For this reason, in the conditions prescribed in advance,
Practical means is needed to allow the magnetic force to be balanced.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the sensitivity of adjusting the magnetic force by adjusting the size of the rotor magnet and the stator magnet, thereby facilitating the adjustment of the magnetic force. It is to make.

An object of the present invention is to make it easy to adjust the magnetic force by generating a repulsive force in the rotation axis direction of the rotor with a magnetic material, and to easily reduce the size of the repulsive magnetic levitation bearing.

SUMMARY OF THE INVENTION An object of the present invention is to divide the stator magnets and adjust the intervals thereof, thereby lowering the rigidity of the rotor in the direction of the rotation axis and reducing the adjustment sensitivity of the magnetic force, thereby facilitating the adjustment of the magnetic force. The purpose is to easily reduce the size of the bearing.

An object of the present invention is to easily adjust the interval between the divided portions of the stator magnet to a target value by interposing a spacer in this case.

[0013]

According to the first aspect of the present invention, a rotor having a vertical rotation axis direction is provided with a rotor magnet made of a permanent magnet, and a stator is made of a permanent magnet which repels and opposes the rotor magnet. In a method of manufacturing a repulsion type magnetic levitation bearing for manufacturing a repulsion type magnetic levitation bearing in which a stator magnet is provided and the rotor is levitated with respect to the stator to support a rotating shaft of the rotor, the method comprises the steps of: The amount of the repulsion is designed to be a parameter for adjusting the component of the repulsion force in the direction of the rotation axis, the repulsion type magnetic levitation bearing is designed, and the amount of the stator magnet is made larger than that of the rotor magnet. This is a method for manufacturing a magnetic levitation bearing.

Therefore, even if conditions such as the shape and weight of the rotor and the stator are predetermined, the adjustment of the magnetic force can be facilitated by lowering the rigidity in the direction of the rotating shaft and reducing the sensitivity of the adjustment of the magnetic force. Therefore, the size of the bearing can be easily reduced.

According to a second aspect of the present invention, in the method of manufacturing a repulsion type magnetic levitation bearing according to the first aspect, a magnetic body is formed on the stator magnet, and the magnetic body is formed in the direction of the rotation axis. The repulsion type magnetic levitation bearing is designed as a parameter for adjusting the component.

Therefore, even if conditions such as the shape and weight of the rotor and the stator are predetermined, a repulsive force in the direction of the rotating shaft is generated by the magnetic material, and the adjustment of the magnetic force is facilitated.
The bearing can be easily miniaturized.

According to a third aspect of the present invention, in the method for manufacturing a repulsion type magnetic levitation bearing according to the first or second aspect, the stator magnet is divided into a plurality in the direction of the rotation axis, and the plurality of stator magnets are used. The repulsion type magnetic levitation bearing is designed by using the interval between the divided portions as a parameter for adjusting the component in the rotation axis direction.

Therefore, even if the conditions such as the shape and weight of the rotor and the stator are predetermined, the adjustment of the magnetic force can be facilitated by lowering the rigidity in the direction of the rotation axis and relaxing the adjustment sensitivity of the magnetic force. Therefore, the size of the bearing can be easily reduced.

According to a fourth aspect of the present invention, a rotor having a vertical rotation axis direction is provided with a rotor magnet made of a permanent magnet, and a stator is provided with a stator magnet made of a permanent magnet which repels and opposes the rotor magnet. In a repulsion type magnetic levitation bearing for magnetically levitating the rotor with respect to the stator and bearing the rotating shaft of the rotor, the amount of the stator magnet is larger than that of the rotor magnet. Bearings.

Therefore, even if conditions such as the shape and weight of the rotor and the stator are predetermined, the amount of the stator magnet is used as a parameter for adjusting the component of the repulsive force in the rotation axis direction, and the amount of the stator magnet is used as the rotor. By increasing the number of magnets, the rigidity in the rotation axis direction is reduced, and the adjustment sensitivity of the magnetic force is reduced, thereby facilitating the adjustment of the magnetic force. Therefore, the size of the bearing can be easily reduced.

According to a fifth aspect of the present invention, in the repulsion type magnetic levitation bearing according to the fourth aspect, the stator magnet has a magnetic flux density distribution around the rotor magnet and the stator magnet which is asymmetric with respect to the rotation axis direction. Characterized in that a magnetic material is formed.

Therefore, even if the conditions such as the shape and weight of the rotor and the stator are predetermined, the formation of the magnetic material is used as a parameter for adjusting the component of the repulsive force in the direction of the rotation axis. By generating a repulsive force, the magnetic force can be easily adjusted, and the bearing can be easily reduced in size.

According to a sixth aspect of the present invention, there is provided the repulsion type magnetic levitation bearing according to the fourth or fifth aspect, wherein a rotor having a vertical rotation axis direction is provided with a rotor magnet made of a permanent magnet, and the rotor is provided on the stator. A repulsion-type magnetic levitation bearing in which a stator magnet made of a permanent magnet is provided so as to face a magnet, and the repulsion force of the two magnets causes the rotor to levitate with respect to the stator so as to support the rotation axis of the rotor, The stator magnet may be divided into a plurality in the rotation axis direction.

Therefore, even if the conditions such as the shape and weight of the rotor and the stator are predetermined, the interval between the divided portions of the stator magnet is used as a parameter for adjusting the component in the rotation axis direction, and the rigidity in the rotation axis direction is reduced. By lowering and lowering the adjustment sensitivity of the magnetic force, the adjustment of the magnetic force can be facilitated, so that the size of the bearing can be easily reduced.

According to a seventh aspect of the present invention, in the repulsion type magnetic levitation bearing according to the sixth aspect, a spacer is interposed between the plurality of divided stator magnets.

Therefore, by interposing the spacer,
The interval between the divided portions of the stator magnet can be easily adjusted to a target value.

According to an eighth aspect of the present invention, there is provided a repulsion type magnetic levitation bearing according to any one of the fourth to seventh aspects, a driving source for rotating the rotor, and a light rotating by the rotation of the rotor to emit light. And a polygon mirror for deflecting and scanning.

Therefore, it is possible to provide an optical deflection scanning device capable of easily reducing the size of the bearing.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment of the Invention] One embodiment of the present invention will be described as a first embodiment of the invention.

FIG. 1 is a longitudinal sectional view of an optical deflection scanning device according to Embodiment 1 of the present invention.

As shown in FIG. 1, this light deflection scanning device 1
Uses a vertical repulsion type magnetic levitation bearing, a rotor 2 which is a round shaft formed of a non-magnetic material and is installed in a vertical direction with an axial direction, and two upper and lower portions of the rotor 2. Rotor magnets 3 and 3 which are ring-shaped permanent magnets formed around the rotor 2 in a circumferential direction;
Is formed on the rotor 2 so as to face the rotor magnet 3,
A rotor magnet 3 and a repelling stator magnet 5 are provided.

A rotary plate 6 having a larger radius than the rotor 2 is provided coaxially at the center in the z direction, and a polygon mirror 7 is formed on the peripheral surface of the rotary plate 6. Further, a drive motor 8 serving as a drive source is disposed above and below the brim portion of the rotating plate 6. Further, a control electromagnet 9 is disposed at an upper portion of the shaft end of the rotor 2, and a z-direction displacement sensor 10 is provided at a lower portion.

FIG. 2 is a block diagram of a control system of the light deflection scanning device 1. As shown in FIG. 2, the z-direction displacement sensor 1
0, a displacement in the z direction (vertical direction) is detected, and this detection signal is sent to the controller 2 via the A / D converter 21.
2 is output. The controller 22 generates a control signal to be given to the control electromagnet 9 based on the detection signal. The control signal is D / A converted by the D / A converter 23, amplified by the amplifier 24, and input to the control electromagnet 9. Accordingly, the displacement in the z direction is detected by the z direction displacement sensor 10 and feedback control is performed so that the position in the z direction is always within a certain range. Therefore, the rotor 2 stably floats by the attraction of the control electromagnet 9. , The controller 22 transmits a control signal to the motor driver 25 for driving the drive motor 8.
, The rotor 2 rotates, and the polygon mirror 7 deflects and scans light (not shown).

In designing the light deflection scanning device 1,
The amount of the stator magnet 5 is used as a parameter for adjusting the component in the z direction of the repulsive force between the rotor magnet 3 and the stator magnet 5. And it turned out that rigidity of az direction can be reduced by making the quantity of the stator magnet 5 larger than the rotor magnet 3. FIG. The rigidity in the z direction refers to the z direction of the magnetic repulsive force generated by the rotor magnet 3 and the stator magnet 5 (this is the vertical direction.
Called the z direction. ) Component, that is, the change rate δF / δz of the z-direction repulsive force (F is the z-direction repulsive force, and z is the z-direction displacement amount). A smaller value means that the adjustment sensitivity is weaker, which means that the magnetic force of the rotor magnet 3 and the stator magnet 5 is more easily adjusted.

FIG. 3 is a diagram showing the arrangement of the rotor magnet 3 and the stator magnet 5 in the light deflection scanning device 1. As shown in FIG. The two rotor magnets 3 are provided at an interval of, for example, 30 mm. Polarity N, S of rotor magnet 3 and stator magnet 5
Is as shown in the figure. The stator magnet 5 is thicker in the z direction than the rotor magnet 3.

According to the light deflection scanning device 1 described above,
Specific and practical adjustment means have been provided to reduce the stiffness in the z-direction. Thereby, the adjustment of the magnetic force can be facilitated by lowering the rigidity in the direction of the rotation axis and reducing the adjustment sensitivity of the magnetic force. This adjusting means can be easily implemented even under conditions where the shape, weight, and the like of the rotor 2 and the stator 4 are determined in advance, and a desired effect can be obtained. Thus, the bearing, and thus the light deflection scanning device 1 can be miniaturized, and can be mounted on a laser beam printer or a laser scanning display device.

Since the rotor 2 and the stator 4 are not in contact with each other, the rotor 2 can be rotated at a high speed. This makes it possible to realize a printer with a high optical writing speed and, consequently, a high printing speed. Alternatively, a display device with excellent image quality can be realized.

Further, the same effect can be obtained by adjusting the magnetic force of the rotor magnet 3 and the stator magnet 5 themselves. However, when such a measure is taken, it is necessary to control the magnetization very precisely, so that the manufacturing cost of the apparatus is inevitably increased. Further, a method of giving a distribution to the coercive force of the rotor magnet 3 and the stator magnet 5 can be considered, but this method is also inferior in terms of manufacturing cost and adjustment cost. The means of adjusting the repulsion balance only with the magnetic parameters of the magnet itself seems to be less realistic. Therefore, according to the first embodiment of the present invention, the above effects can be realized at low manufacturing cost.

[Second Embodiment of the Invention] Another embodiment of the present invention will be described as a second embodiment of the present invention.

FIG. 6 is a longitudinal sectional view of an optical deflection scanning device according to the second embodiment of the present invention. FIG. 7 is a diagram showing an arrangement of a rotor magnet and a stator magnet in the light deflection scanning device. In the optical deflection scanning device 1 according to the second embodiment of the present invention, members and the like common to the first embodiment of the present invention are denoted by the same reference numerals as those of the first embodiment of the present invention, and detailed description thereof will be omitted.

Light deflection scanning device 1 according to Embodiment 2 of the present invention
However, the difference from the first embodiment of the invention is that the outer periphery of the stator magnet 5 is covered with a ring-shaped magnetic body 11. That is, the magnetic material 1 is attached to the stator magnet 5.
1 is formed, and the formation of the magnetic body 11 is used as a parameter for adjusting the component of the magnetic field generated by the rotor magnet and the stator magnet in the z-direction to design a repulsion type magnetic levitation bearing.
As a result, not only the rigidity is reduced as in the case of the first embodiment of the invention, but also the magnetic flux density distribution between the rotor magnet 3 and the stator magnet 5 becomes asymmetric, and as shown in FIG. A repulsive force in the z direction is generated around the point. The magnetic body 11 is desirably coated on the z-direction upper side of the outer peripheral surface of the stator magnet.

As described above, by making the stator magnet 5 larger than the rotor magnet 3 and coating the outer periphery of the stator magnet 5 with the ring-shaped magnetic body 11, the magnetic flux density distribution between the rotor magnet 3 and the stator magnet 5 is increased. Becomes asymmetric, and the controllability of the magnetic force can be improved. This adjusting means can be easily implemented even under conditions where the shape, weight, and the like of the rotor 2 and the stator 4 are determined in advance, and a desired effect can be obtained. Thus, the bearing, and thus the light deflection scanning device 1 can be miniaturized, and can be mounted on a laser beam printer or a laser scanning display device.

Since the rotor 2 and the stator 4 are not in contact with each other, the rotor 2 can be rotated at a high speed. This makes it possible to realize a printer with a high optical writing speed and, consequently, a high printing speed. Alternatively, a display device with excellent image quality can be realized.

In addition, the above effects can be realized at low manufacturing cost.

Third Embodiment of the Invention Another embodiment of the present invention will be described as a third embodiment of the present invention.

FIG. 12 is a longitudinal sectional view of an optical deflection scanning device according to Embodiment 3 of the present invention. Third Embodiment of the Invention
In the optical deflection scanning device 1 of the first embodiment, members and the like common to the first embodiment of the invention are denoted by the same reference numerals as those of the first embodiment of the invention.
Detailed description is omitted.

Light Deflection Scanning Device 1 of Embodiment 3 of the Invention
However, the difference from the first embodiment of the present invention is that the stator magnet 5 is divided into a plurality of pieces, in this example, two pieces to form stator magnet pieces 5a and 5b. That is, the stator magnet 5 is a plurality of stator magnet pieces 5 divided in the z direction.
The repulsion type magnetic levitation bearing is designed by using the distances a and 5b and setting the interval between the stator magnet pieces 5a and 5b as a parameter for adjusting the component in the z direction. Specifically, the two stator magnet pieces 5a and 5b are both oriented and magnetized in the z direction,
Opposite surfaces of the two stator magnet pieces 5a and 5b are arranged so that the polarities are opposite to each other, and the stator magnet 5 is made larger than the rotor magnet 3. As a result, the rigidity decreases as in the first embodiment of the invention. Not only that, the adjustment of the magnetic force can be facilitated by adjusting the distance between the two stator magnet pieces 5a and 5b to lower the rigidity of the rotor 2 in the z-direction and loosening the adjustment sensitivity of the magnetic force. It is possible (see FIG. 13).

In this case, as shown in FIG. 14, a ring-shaped spacer 12 made of a non-magnetic material is interposed between the two stator magnet pieces 5a and 5b, so that the distance between them can be adjusted. Thereby, the rigidity of the rotor 2 in the rotation axis direction can be easily adjusted, that is, the rate of change δF / δz of the component of the magnetic force in the z direction of the rotor 2 can be adjusted. ΔF / than when there is no space between the two stator magnet pieces 5a and 5b.
δz can be reduced. Therefore, the adjustment sensitivity of the magnetic force balance can be relaxed by the spacer 12, and the adjustment accuracy of the magnetic force balance can be increased. In addition, 2
The sum of the thicknesses of the three stator magnet pieces 5a and 5b is set to be larger than that of the rotor magnet 3.

The rigidity can be easily changed by changing the thickness of the spacer 12. If the spacer 12 is too thick, the horizontal direction (hereinafter, referred to as r direction) component of the magnetic force causes a lateral shift, so that it can be seen that there is an appropriate thickness range.

As described above, the rigidity of the rotor 2 in the rotation axis direction can be easily adjusted by using the spacer 12 which is a simple adjusting member. Thus, the bearing, and thus the light deflection scanning device 1 can be miniaturized, and can be mounted on a laser beam printer or a laser scanning display device.

Since the rotor 2 and the stator 4 are not in contact with each other, the rotor 2 can be rotated at a high speed. This makes it possible to realize a printer with a high optical writing speed and, consequently, a high printing speed. Alternatively, a display device with excellent image quality can be realized.

Further, the above-mentioned effect can be realized at low manufacturing cost.

As shown in FIGS. 17 and 18, the magnetic body 11 used in the second embodiment of the present invention may be provided.

[0054]

[Example 1] An example corresponding to the first embodiment of the present invention will be described. In the deflection scanning device 1 described above with reference to FIG. 1, the rotor magnet 3 and the stator magnet 5 are manufactured and compared under the following configuration conditions A and B. It was confirmed that the rigidity in the z direction can be reduced by increasing the amount of.

Construction condition A: inner diameter of rotor magnet 3 is 2 mm
Φ, outer diameter 6 mmΦ, thickness 3 mm, made of Nd-Fe-B material, the stator magnet 5 has inner diameter 9 mmΦ, outer diameter 14 mm
It was composed of a Nd-Fe-B material having a thickness of 8 mm and a diameter of 8 mm.

Construction condition B: rotor magnet 3 has an inner diameter of 2 mm
Φ, outer diameter 6 mmΦ, thickness 3 mm, made of Nd-Fe-B material, the stator magnet 5 has inner diameter 9 mmΦ, outer diameter 14 mm
Φ, 4 mm thick made of Nd-Fe-B material.

FIG. 4 is a longitudinal sectional view of the rotor magnet 3 and the stator magnet 5 of the optical deflection scanning device 1 according to the first embodiment.
In the configuration condition A, the rotor magnet 3 and the stator magnet 5
Are approximately the same size. Under the configuration condition B, the thickness of the stator magnet 5 was twice as large as that of the rotor magnet 3. 0 in the figure
The point position indicates the position in the z direction (= 0).

FIG. 5 shows the configuration conditions A and B in the first embodiment.
It is a graph which shows the relationship between the displacement of az direction, and a repulsion force about each case. Comparing the configuration conditions A and B,
It can be seen that in the case of the configuration condition B, the gradient of the z-direction repulsion force with respect to the z-direction displacement at the point 0 is gentler than in the case of the configuration condition A.

[Example 2] An example corresponding to the second embodiment of the present invention will be described. In the deflection scanning device 1 described above with reference to FIG. 6, in the comparison between the configuration condition A and the conventional configuration condition B, the rotor magnet 3 and the stator magnet 5 are manufactured under the following configuration conditions A and B. As a result of comparison, the magnetic flux density distribution between the rotor 2 and the stator 4 is distorted, and z
A repulsive force in the z direction could be generated at the center point in the direction. When the magnetic body 11 was not covered, such a repulsive force was not obtained.

Construction condition A: inner diameter of rotor magnet 3 is 2 mm
Φ, outer diameter 6 mmΦ, thickness 3 mm, made of Nd-Fe-B material, the stator magnet 5 has inner diameter 9 mmΦ, outer diameter 14 mm
Φ, 8 mm thick made of Nd-Fe-B material, S45
The ring-shaped magnetic body 11 made of C material has an inner diameter of 14 mm.
Φ, outer diameter 15mmΦ, thickness 4mm, stator magnet 5
Was provided in a region 4 mm above the outer peripheral portion.

Construction condition B: rotor magnet 3 has an inner diameter of 2 mm
Φ, outer diameter 6 mmΦ, thickness 3 mm, made of Nd-Fe-B material, the stator magnet 5 has inner diameter 9 mmΦ, outer diameter 14 mm
It was composed of an Nd-Fe-B material having a thickness of 8 mm and no magnetic material 11.

FIG. 9 is a conceptual diagram showing magnetic flux lines near the rotor magnet 3 and the stator magnet 5 under the configuration condition B. FIG.
FIG. 3 is a conceptual diagram showing magnetic flux lines near a stator magnet 5. FIG.
10 and FIG. 10, it can be seen that the magnetic body 11 is coated so that the magnetic flux lines between the rotor magnet 3 and the stator magnet 5 become asymmetric, and a repulsive force in the z direction is generated.

FIG. 11 shows the configuration conditions A,
9B is a graph showing the relationship between the displacement in the z direction and the repulsive force in each case B. From this graph, it can be seen that the magnetic material 1
It can be seen that the coating of 1 makes the magnetic flux lines between the rotor magnet 3 and the stator magnet 5 asymmetric, and generates a repulsive force in the z direction.

[Embodiment 3] An embodiment corresponding to Embodiment 3 of the present invention will be described. In the deflection scanning device 1 described above with reference to FIG. 12, the rotor magnet 3 is made of an Nd—Fe—B material having an inner diameter of 2 mmΦ, an outer diameter of 6 mmΦ, and a thickness of 3 mm.
The stator magnet 5 made of Nd—Fe—B material has an inner diameter of 9 mm.
When two pieces having a diameter of 4 mm and an outer diameter of 14 mm and a thickness of 4 mm were used as the stator magnet pieces 5a and 5b, it was confirmed that the rigidity in the z direction could be reduced. FIG. 15 is a conceptual diagram showing magnetic flux lines near the rotor magnet 3 and the stator magnet 5 in this case. By providing a gap between the two stator magnet pieces 5a and 5b, the rotor magnet 3 and the stator magnet 5
It can be seen that the magnetic flux lines between the two have changed.

FIG. 16 shows a case where the spacer 12 having no thickness is used and the spacer 12 having a thickness of 0.42 mm is used.
It is a graph which shows the relationship between the displacement of az direction, and a repulsion force about each case where the spacer 12 of 0 mm is used. It can be seen that by providing the spacer 12, the rate of change of the z-direction repulsion near zero displacement in the z-direction, that is, the gradient, can be changed depending on the thickness of the spacer 12.

When the 1.0 mm spacer 12 is used, the rigidity (δF / δz) becomes negative. In this case, since a restoring force (a negative force is generated with respect to the displacement in the + z direction) acts in the z direction, the spontaneous (passive) action occurs in the z direction.
Stable. However, at this time, it is obvious that a lateral displacement force acts in the horizontal (r) direction according to the Ernshaw's theorem.

The Ernshaw's theorem states that "when there is an electric charge in an electrostatic field, no matter how it is devised, it cannot be stably levitated by electrostatic force." Considering the characteristics, it can be said that no matter how the static magnetic field (magnet arrangement) is devised, it is not possible to stably levitate only with the static magnetic force.

The Yonet's stiffness theorem is that “the sum of stiffness in each coordinate axis direction is zero”. In a certain coordinate system (x, y, z), the stiffness in each coordinate axis direction is represented by Kx,
Assuming that Ky and Kz, Kx + Ky + Kz = 0 holds.

In the above case, if the rigidity in the z direction is negative,
It can be seen that the rigidity of the other coordinate axes is naturally positive, and a lateral displacement force is generated.

[Embodiment 4] In Embodiment 3, the magnetic material 11 was used.
This is an example in the case of providing. That is, the rotor magnet 3
Nd-Fe with inner diameter 2mmΦ, outer diameter 6mmΦ, thickness 3mm
-B material, two stator magnet pieces 5a, 5b
Is Nd with an inner diameter of 9 mmΦ, an outer diameter of 14 mmΦ, and a thickness of 4 mm.
-The magnetic body 11 made of the Fe-B material and made of the S45C material has an inner diameter of 14 mmΦ, an outer diameter of 15 mmΦ, and a thickness of 4 m.
m, and the device was installed in a region 4 mm above the outer peripheral portion of the stator magnet 5. Also, between the two stator magnet pieces 5a and 5b, the inner diameter is 9 mmΦ, the outer diameter is 20 mmΦ, and the thickness is 0.28 mm.
Are provided. FIG. 19 is a graph showing the relationship between the displacement in the z direction and the repulsive force in the case where the magnetic body 11 is formed and in the case where the magnetic body 11 is not formed. As shown in FIG. 19, when the magnetic body 11 was formed, a repulsive force in the z direction of 1.2 N was obtained. Also, it can be seen that the change rate of the z-direction repulsive force, that is, the gradient, can be made gentle near the zero point of the z-direction displacement, and the z-direction repulsive force can be generated near the zero point of the z-direction displacement.

[0071]

According to the first aspect of the present invention, even if conditions such as the shape and weight of the rotor and the stator are predetermined, the rigidity in the direction of the rotating shaft is reduced, and the sensitivity for adjusting the magnetic force is reduced to thereby reduce the magnetic force. Can be easily adjusted, so that the size of the bearing can be easily reduced.

According to a second aspect of the present invention, in the method for manufacturing a repulsion type magnetic levitation bearing according to the first aspect, even if conditions such as the shape and weight of the rotor and the stator are predetermined.
A repulsive force in the direction of the rotation axis is generated by the magnetic material, so that the adjustment of the magnetic force is facilitated, and the size of the bearing can be easily reduced.

According to a third aspect of the present invention, in the method of manufacturing a repulsion type magnetic levitation bearing according to the first or second aspect, even if conditions such as shapes and weights of the rotor and the stator are determined in advance, the rotational axis direction By lowering the stiffness and loosening the adjustment sensitivity of the magnetic force, the adjustment of the magnetic force can be facilitated, so that the size of the bearing can be easily reduced.

According to the fourth aspect of the present invention, even if conditions such as the shape and weight of the rotor and the stator are predetermined, the amount of the stator magnet is used as a parameter for adjusting the component of the repulsive force in the rotation axis direction. By increasing the amount of stator magnets compared to the rotor magnets, the rigidity in the direction of the rotation axis is reduced, and the sensitivity of the adjustment of the magnetic force is reduced, making it easier to adjust the magnetic force. can do.

According to a fifth aspect of the present invention, in the repulsion type magnetic levitation bearing of the fourth aspect, even if conditions such as the shape and weight of the rotor and the stator are determined in advance, the formation of the magnetic material is reduced by the repulsion force. A parameter for adjusting the component in the rotation axis direction is used, and a repulsive force in the rotation axis direction is generated by the magnetic material, so that the adjustment of the magnetic force is facilitated and the bearing can be easily reduced in size.

According to a sixth aspect of the present invention, in the repulsion type magnetic levitation bearing according to the fourth or fifth aspect, even if conditions such as the shapes and weights of the rotor and the stator are predetermined, the divided portions of the stator magnets are separated. By setting the interval as a parameter for adjusting the component in the rotation axis direction, lowering the rigidity in the rotation axis direction and relaxing the magnetic force adjustment sensitivity, it is possible to easily adjust the magnetic force, so that the bearing can be easily adjusted. The size can be reduced.

According to a seventh aspect of the present invention, in the repulsion type magnetic levitation bearing according to the sixth aspect, the interval between the divided portions of the stator magnet can be easily adjusted to a target value by interposing a spacer. Can be.

The invention described in claim 8 can provide an optical deflection scanning device capable of easily reducing the size of a bearing.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an optical deflection scanning device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a control system of the light deflection scanning device.

FIG. 3 is a diagram showing an arrangement of a rotor magnet and a stator magnet in the optical deflection scanning device.

FIG. 4 is a longitudinal sectional view of a rotor magnet and a stator magnet of the optical deflection scanning device according to the first embodiment.

FIG. 5 is a graph showing the relationship between the displacement in the z direction and the repulsive force for each of the configuration conditions A and B in the first embodiment.

FIG. 6 is a longitudinal sectional view of a light deflection scanning device according to a second embodiment of the present invention.

FIG. 7 is a diagram showing an arrangement of a rotor magnet and a stator magnet in the optical deflection scanning device.

FIG. 8 is a diagram showing an arrangement of a rotor magnet and a stator magnet in the light deflection scanning device.

FIG. 9 is a conceptual diagram illustrating magnetic flux lines near a rotor magnet and a stator magnet in a case of a configuration condition B according to the second embodiment.

FIG. 10 is a conceptual diagram showing magnetic flux lines near the rotor magnet and the stator magnet in the case of the configuration condition A in the second embodiment.

FIG. 11 is a graph showing the relationship between the displacement in the z direction and the repulsive force for each of the configuration conditions A and B in the second embodiment.

FIG. 12 is a longitudinal sectional view of an optical deflection scanning device according to a third embodiment of the present invention.

FIG. 13 is a diagram showing an arrangement of a rotor magnet and a stator magnet in the optical deflection scanning device.

FIG. 14 is a diagram showing an arrangement of a rotor magnet, a stator magnet, and a spacer in the optical deflection scanning device.

FIG. 15 is a conceptual diagram showing magnetic flux lines near a rotor magnet and a stator magnet in a second embodiment.

FIG. 16 is a graph showing the relationship between the displacement in the z direction and the repulsive force in Example 3.

FIG. 17 is a longitudinal sectional view when a magnetic body is formed in the optical deflection scanning device according to the third embodiment of the present invention.

FIG. 18 is a cross-sectional view of the light deflection scanning device,
FIG. 3 is a longitudinal sectional view showing an arrangement of a stator magnet, a spacer, and a magnetic body.

FIG. 19 shows a case where a magnetic body is formed in Example 4;
It is a graph which shows the relationship between the displacement of az direction, and a repulsive force about each case where it did not do.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical deflection scanning device 2 Rotor 3 Rotor magnet 4 Stator 5 Stator magnet

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takahisa Oji 2-40-20 Kotano, Kanazawa-shi, Ishikawa F-term in the electromagnetic field control experimental facility attached to the Faculty of Engineering, Kanazawa University 2H045 AA14 AA15 AA24 AA28 AA62 DA41 3J102 AA01 DA03 DA07 DA11 GA02

Claims (8)

[Claims] A rotor having a vertical rotation axis direction provided with a rotor magnet made of a permanent magnet, and a stator provided with a stator magnet made of a permanent magnet opposed to and repelled by the rotor magnet; A method of manufacturing a repulsion type magnetic levitation bearing for manufacturing a repulsion type magnetic levitation bearing in which a rotor is levitated with respect to the stator to support a rotation shaft of the rotor, comprising: A method for manufacturing a repulsion type magnetic levitation bearing, wherein the repulsion type magnetic levitation bearing is designed as a parameter for adjusting the components of the above, and the amount of the stator magnet is made larger than that of the rotor magnet. 2. A magnetic body is formed on the stator magnet,
The method for manufacturing a repulsion-type magnetic levitation bearing according to claim 1, wherein the repulsion-type magnetic levitation bearing is designed by using the formation of the magnetic material as a parameter for adjusting the component in the rotation axis direction. 3. The repulsion type magnetic levitation, wherein the stator magnet is divided into a plurality in the rotation axis direction, and an interval between the plurality of divided portions is set as a parameter for adjusting a component in the rotation axis direction. The method for manufacturing a repulsion type magnetic levitation bearing according to claim 1, wherein the bearing is designed. 4. A rotor having a vertical rotation axis direction is provided with a rotor magnet made of a permanent magnet, and a stator is provided with a stator magnet made of a permanent magnet that repels and opposes the rotor magnet. A repulsive magnetic levitation bearing in which a rotor floats with respect to the stator to support a rotating shaft of the rotor, wherein the amount of the stator magnet is larger than that of the rotor magnet. 5. The repulsion according to claim 4, wherein the stator magnet is formed of a magnetic material that makes the magnetic flux density distribution around the rotor magnet and the stator magnet asymmetric with respect to the rotation axis direction. Type magnetic levitation bearing. 6. The repulsion type magnetic levitation bearing according to claim 4, wherein the stator magnet is divided into a plurality in the rotation axis direction. 7. The repulsion type magnetic levitation bearing according to claim 6, wherein a spacer is interposed between the plurality of divided stator magnets. 8. A repulsion type magnetic levitation bearing according to claim 4, a drive source for rotating said rotor, a polygon mirror which is rotated by rotation of said rotor and deflects and scans light. An optical deflection scanning device comprising: