JPS6387162A - Motor - Google Patents

Abstract

PURPOSE:To improve abrasion resistance and corrosion resistance, by providing a sliding section between a rotor and a stator, with a plate-formed dynamic- pressure bearing made of hard ceramics material. CONSTITUTION:As one of end surfaces in the direction of the rotary shaft of a rotor 10, a rotating side sliding surface is formed to compose a brushless flat motor. The rotor 10 is composed of a yoke 1 made of dish-formed iron, a ring-formed permanent magnet 2 fitted and fixed on the yoke, and a ceramics plate 100 fitted firmly on both the component parts. For the ceramics plate 100, hard ceramics material is used, and on the flat surface of the side surface 9 of a stator, a groove for dynamic pressure generation is formed. On the other hand, on the side of the stator, a stator coil 4 is fixed at a fixing plate 6, and on the coil, the fixing side hearing 3 of the ceramics material is fixed. Besides, the bearing 3 and the sliding surface 9 are provided with recessed sections 11-12 to contain a small ball 7. Then, by the rotation of the rotor 10, the dynamic pressure of fluid 14 is generated on sliding sections, and the rotor 10 is levitated, and sliding resistance is lowered.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electric machine, and particularly to an electric machine having a flat structure in which a rotor and a stator are arranged with a magnetic gap in the direction of the rotational axis of the rotor. Moreover, the present invention relates to an electric machine that does not require a drive shaft for transmitting rotational force.

[Prior Art] FIG. 11 is a vertical sectional view of a brushless flat motor, which is an example of a conventional electric machine. A base 21 and a board 22 for attaching stake coils are connected by stator bolts 23, and a rotor magnet is fixed to a motor shaft 26 which is pivotally mounted on bearings 24 and 25 fixed to the base 21 and the board 22, respectively. 27 is fixed. A stator coil 28 is fixed to the rotor 27 with the substrate 22 interposed therebetween, and a tacho generator 33 generated by the rotor 27 and a Hall element 29 for controlling the rotation speed are fixed to the substrate 22. The structure is the same for a sheet coil motor in which a motor coil is mounted by photo-etching in which the stator coil is 4Ml.

This electric machine can be used as a laser scanner by fixing a polygon mirror to the motor shaft 26, as an optical disk drive device by detachably fixing an optical disk directly to the rotor 21, or as an optical disk drive device by fixing an optical disk directly to the rotor 21. There are various types, such as a fan with a fixed base attached to it and used as a blower.

[Problems to be Solved by the Invention] In the electric machine as described above, the radial clearance between the bearings 24 and 25 is large, and the rotor 27 may vibrate.

In particular, ball bearings are used for the bearings 24 and 25, which may generate vibrations, which is a problem in tape recorders and VTRs that are sensitive to vibrations.

Furthermore, without a shaft sealing means, radial bearings do not have excellent corrosion resistance and cannot withstand use underwater. Furthermore, the durability was insufficient even in environments where dew condensation was repeated.

In addition, rotational unevenness is a particular problem in motors used in electronic application products, and the variation in frictional resistance in the radial bearing portion is large, which can sometimes cause rotational unevenness.

Although it is often preferable for such an electric machine to be thin with a short axial length, the motor cannot be made thin unless the distance between the radial bearings 24 and 25 is shortened. If the distance between the radial bearings is shortened, the bearing load on the radial cart will increase, and the inclination of the motor shaft due to the bearing gap will also increase.

Generally speaking, in this type of electric machine, the thrust load from the rotor magnet is constantly applied, and if the machine is stopped for a long time, the metal balls and retainers of the ball bearings may become permanently deformed, making it impossible to start. be. In addition, when used as a high-speed laser scanner that reproduces highly clear images, the machining precision of the motor shaft 26 and bearings 24 and 25 must be extremely high in order to reduce the amount of vibration of the surface of the polygon mirror, and at the same time, The assembly precision with the polygon mirror must also be high.

[Objective] The present invention provides an electric machine with a simple structure and high durability, in which a rotor and a stator are arranged with a magnetic gap in the direction of the rotational axis of the rotor. It also provides an electric machine that minimizes rotor vibration and surface shaking.It also has excellent durability and wear resistance, and can be used in a wide range of environments such as in gases and liquids. The present invention provides an electric machine that can be used in a usage environment.

[Means for Solving the Problems] The present invention provides an electric machine in which a stator is disposed opposite to an end face of a rotor in the rotation axis direction, and a rotation side sliding surface is formed on an end face of the rotor facing the stator. The stator surface facing the rotating side sliding surface is a fixed side bearing surface, the rotating side sliding surface and the fixed side bearing surface are each made of a hard ceramic material ffl, and the rotating side I
This is an electric machine in which one of the S moving surface and the stationary bearing surface is a smooth plane, and the other surface is a plane with grooves for generating dynamic pressure.

Furthermore, in a second aspect of the present invention, rotation side 11 arm movement surfaces are formed on both end surfaces of the rotor in the direction of the rotation axis, and the stator is arranged opposite to the rotation side 1 movement surface on the - side, The other rotating side! S
In an electric machine having a swingable bearing surface facing the moving surface, the surface of the stator facing the rotating side sliding surface is the stationary side bearing surface, and the two rotating side sliding surfaces and the opposing surface are arranged as a fixed side bearing surface. each of the two bearing surfaces made of a hard ceramic material, and
An electric machine is used in which a groove for generating dynamic pressure is provided on one of the two surfaces constituting the sliding portion formed by both end surfaces of the rotor in the rotational axis direction, and the other surface is made a smooth plane.

Furthermore, in a third aspect of the present invention, rotating side sliding surfaces are formed on both end surfaces of the rotor in the direction of the rotating shaft, the stator is disposed opposite to one rotating side sliding surface, and the stator is disposed opposite to one rotating side sliding surface, and In an electric machine having a swingable bearing surface facing a rotating sliding surface of the rotor, a fixed shaft extending on the rotational axis of the rotor is fixed to the stator, and a shaft corresponding to the fixed shaft is fixed to the stator. A through hole is formed in the center of the rotor to form a radial shaft, the surface of the stator opposite to the rotating side sliding surface is a stationary side bearing surface, and the two rotating side sliding surfaces and the two opposite thereto.
Each of the two bearing surfaces is made of a hard ceramic material, and a groove for generating dynamic pressure is provided on one of the two surfaces forming the sliding part formed on both end surfaces in the direction of the rotor's rotational axis. , an electric machine whose other surface is a smooth plane.

[Function 1] In the electric machine of the present invention, the sliding parts between the rotor and the stator are each made of a hard ceramic material, and grooves for generating dynamic pressure are formed on one of the surfaces. As the rotor rotates, fluid dynamic pressure is generated in the sliding part, and the rotor floats and rotates, and the surrounding resistance at this time is extremely small.

Moreover, the vibration of the rotor is suppressed by the damping effect of the fluid film formed on the sliding portion.

In the second aspect, since both end surfaces of the rotor in the direction of the rotational axis are supported by sliding portions each having a damping effect, the rotor is less likely to be photographed.

Furthermore, in the third aspect, a sliding part that supports a radial load is formed between the sweeping hole formed in the center of the U-shaped shaft and the fixed shaft, but a fluid film is similarly formed. To be that! Resistance to imperial orders is small.

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

FIG. 1 is a longitudinal sectional view of a general-purpose brushless flat motor in which a rotary side 1 moving surface is formed on one end surface in the rotational axis direction of a rotor 10. A dish-shaped iron yoke 1 with a circular plane] A rotor 10 is constituted by an annular permanent magnet 2 fitted and fixed to the yoke 1 and a ceramic plate 100 fixed to the yoke 1 and the permanent magnet 2 on the inner periphery of the permanent magnet 2.

7 South permanent fj 1 stone 2 has multiple magnetic 4 se or equal intervals in a ring! It is magnetized with The ceramic plate 700 is made of a ceramic material with ra=rs, for example, β-5iC, α-S*C.

A dense ceramic such as Si3N4 is used, and the stake-side surface 9 is a smooth plane with grooves for generating dynamic pressure formed therein. That is, the rotating side 1n moving member 9 facing this stator
The waviness on the entire surface is less than 1 μm, and a spiral groove with a depth of 3 to 50 μm is machined as a groove for generating dynamic pressure. A recess 12 is formed.

On the other hand, on the stator side, a stator coil 4 is fixed to a fixed number 6 fixed to a fixed side member (not shown) with screws, and a fixed side bearing 3 made of a hard ceramic material is further fixed on the stator coil 4.

The stator coil 4 is made up of a plurality of sheet-like coils bonded and fixed, and includes a Hall element 29 for detecting the magnetic pole of the permanent magnet 2 of the rotor 1o, and a tacho generator 33 for detecting the rotational speed of the rotor 10. are fixed together. Furthermore, the surface 8 of the stationary side bearing 3 fixed to the stator coil 4 in correspondence with the rotating side sliding surface 9 of the rotor 1o is processed into a smooth flat surface with less waviness, similar to the rotating side 1 sliding surface 9. , a hemispherical recess 11 is also formed at a position corresponding to the rotation axis of the rotor. Then, a small ball 7 made of plastic, metal, or ceramics is housed in the space formed by the two recesses 11 and 12, and the ball 4 is arranged to support a small radial load.
1 has been done. FIG. 2 is an enlarged sectional view of the central portion of the rotating side sliding surface 9 and the stationary side bearing surface 8 shown in FIG.

Hemispherical recesses 1 formed on the rotating shaft 13 of the rotor, respectively.
The space formed by 1.12 is approximately spherical, and a small sphere 7 smaller than the space is housed 8. Furthermore, when the rotary side sliding surface 9 of the ceramic plate 100 and the fixed side bearing surface 8 of the fixed side bearing 3 are in contact with each other, there is actually no gap in terms of τ1 when the rotor 10 is stationary. However, when the rotor 10 rotates, dynamic pressure of the fluid 14 is generated in this sliding portion, causing the rotor 10 to float. The flying height of the rotor 10 is determined by various factors such as the viscosity of the fluid in the sliding part, the rotational speed of the rotor 10, the thrust load in the sliding part, and the shape of the iM for generating dynamic pressure. The viscosity of the upper fluid has a particularly large effect.

FIG. 3 is a front view of the rotation side sliding surface 9, in which a unidirectional spiral groove 15 is formed on a circular ceramic plate 100, and the center 16 of the ceramic plate has the same depth as the groove 15. It is processed into. Of course, the center 16 may be at the same height as the smooth plane like the land portion 17 adjacent to the spiral groove 15, or may be machined deeper than the spiral groove 15.

However, in this type of electric machine, since the fetal movement torque becomes large, the land portion 1, which is a convex portion on the rotating side sliding surface 9,
It is desirable to reduce the area of 7.

FIG. 3 shows arrow A (direction in which the rotor 10 rotates, and since the rotating side sliding surface 9 also rotates together with the rotor 10, the fluid 14 flows from the outer circumferential side toward the center 16 by the spiral groove 15). However, in the spiral groove 15 portion, a large dynamic pressure is generated from the outer peripheral end to the inner peripheral end,
The pressure distribution is roughly uniform in the center 16. still,
The magnitude of the dynamic pressure generated here is proportional to the magnitude of the force with which the rotor 10 is pressed against the stator 101, and the rotor 10 and stator 101 are connected via a fluid film to an extremely small Can be rotated by dynamic resistance.

The most protruding part of the rotating side sliding surface 9 is the land part 17, and the waviness therein is within 1 μm, and the protruding part on the bearing surface 8 side is roughly the same as this smooth bearing surface. The undulation on the entire surface is also 1μ.
It is within m.

In addition, the fluid interposed in this sliding part is the rotating side sliding surface 9.
Since the distance between the bearing surface 8 on the fixed side and the bearing surface 8 on the fixed side is narrow, it also has a damping effect and suppresses sudden changes in the distance between the sliding parts.
The vibration in the direction of the rotation axis is extremely small. Since the distance between the sliding parts is small and stable in this way, the distance between the permanent magnets 2 of the rotor 10 and the stator coil 4 is also small, and the magnetic field generated by the coil 4 is effectively transferred to the rotor 10 side. communicated. The fixing plate 6 on the back side of the coil 4 may be made of silicon steel in order to prevent leakage of magnetic flux.

Here, since the hard ceramic material used as the stationary side bearing 3 interposed between the stator coil 4 and the permanent magnet 2 is inserted into a rotating magnetic field, electrical A material with a high resistance is preferable, and among the above ceramic materials, Si3N4 or B
It is desirable to use α-SiC doped with eO.

In FIG. 1, the surface on which the grooves for generating dynamic pressure are formed may be the stationary side bearing surface 8. In that case, the rotating side sliding surface 9 on the rotor 10 side facing this may be a smooth flat surface. Use the one left as is.

FIG. 4 is a longitudinal sectional view of an embodiment in which both ends can output.

A coil 4 made of stacked sheet coils is fixed from both sides by two ceramic fixed-side bearings 3, 3, and the fixed-side bearings 3, 3 have a smooth bearing surface 8°8 in the center, and the tacho generator 33 is more concave than the central bearing surface 8 to prevent solid contact with the opposing surface of the rotor 10.

In FIG. 4, the position of the permanent magnet 2 attached to the rotor 10 on the lower side is detected by the Hall element 29, and a predetermined coil 4 is energized from a control device (not shown) to rotate the lower rotor 10. Become.

The magnetic flux generated by the coil 4 at this time also appears on the upper surface of the coil 4, so that the upper rotor 10 also rotates in the same way.

However, the opposing poles of the upper and lower rotors 10 are completely opposite, and as a result, the rotors 10 and 10 attract each other, and the two rotors 1
0.10 is held in the stator.

Note that the small ball 7 corresponds to a type of radial bearing. With this small ball 7, the rotor 10.10 and the stator 1
01 from moving in the radial direction, and also serves as a guide for determining the position. As mentioned above, small balls include iron balls, stainless steel balls,
In addition to ceramic spheres, shapes include cylinders, cones, and
A variety of answers are available.

In the present invention, the main reasons for using hard V1 ceramics + A material as the members constituting the moving parts are that it is possible to machine grooves for generating dynamic pressure with high precision, and The suitable shape of the 1-shaft part is maintained even when dynamic pressure is generated, and it is durable against solid friction that occurs when starting and stopping, provided the load is at the necessary level. It is.

In addition, as a method of machining grooves for generating dynamic pressure on the surface of a hard ceramic material, a resin mask corresponding to the land is attached to the surface of the ceramic material 11 that has been finished into a smooth plane, or a resin mask corresponding to the land is attached. Screen mark on the corresponding part! After applying the resin using a method such as jl and curing it, apply 120 ml to the exposed ceramic part.
This shot blasting process is carried out by blowing 3 particles, SiC particles, etc. with high pressure air, and after this shot blasting process, the resin layer on the surface of the ceramics may be removed. As a result, the land becomes a smooth flat surface as it was when finished, and the groove becomes a satin finished surface. Note that when manufacturing a radial bearing that utilizes the hydrodynamic effect, which will be described later, grooves can be formed by the above-mentioned shot blasting.

Broadly speaking, the electric machine of the present invention can be used for various purposes, such as forming a polygon mirror by forming a polygon mirror on the outer periphery of the rotor, fixing a row directly to the rotor to use it as a pump, A means for removably fixing a disk is provided on the upper surface of the rotor to form a drive device for a magnetic disk or optical disk.

FIG. 5 is a longitudinal cross-sectional view when the electric machine according to the second aspect of the present invention is used as a driving device for a polygon mirror.

In FIG. 5, 50 is a support base fastened to a fixing member (not shown), and a cap 51 is arranged on the support base 50 so as to be screwed. The cap 51 isolates the internal rotating part from the outside world, and a glass window 53 is provided at a position corresponding to the polygon mirror 52 inside.

A stator coil 54 is fixed to the support base 50, and on the upper surface of the stator coil 54 is a fixed-side bearing 55 made of a hard ceramic disc with a smooth surface.
is fixed, and the smooth plane 56 becomes the fixed side bearing surface.

A hemispherical recess 57 is formed in the fixed side bearing surface 56 at a position corresponding to the rotation axis of the polygon mirror 52.
A groove for generating dynamic pressure is formed on the outside of 7. A polygon mirror 52 is rotatably installed above the fixed side bearing 55, and a press plate 58 is provided above the polygon mirror 52.

The polygon mirror 52 has a lower rotating side sliding plate 59 made of a hard ceramic material on the surface facing the stator coil 54 and an upper rotating side sliding plate 59 made of a hard ceramic material on the surface facing the pressing plate 58. Eternal 11 between
A stone 61 and a part of Mira 62 are fixed. The surfaces of the lower and upper rotation side sliding plates 59.60 are similarly polished to flat surfaces with few undulations, and are each provided with hemispherical recesses 63.6 at positions on the rotation axis of the polygon mirror 52.
4 is formed. The pressing plate 58 is a back plate 65 made of iron.
, a rubber plate 66 and a bearing plate 67 made of a hard ceramic material (2) are laminated and bonded together.
faces the polygon mirror 52.

Roughly, the back plate 65 and the cap 51 are elastically connected by a spring 68, and the temporary 58 is pressed against the polygon mirror 52.
It's being pushed to. A solenoid 69 is provided inside the spring 68, and when the solenoid 69 is powered on, the back plate 5
8 is attracted to the solenoid 69, and the pressing force on the polygon mirror 52 is reduced or eliminated.

The surface (lower surface in the figure) of the bearing plate 67 is a smooth flat surface with few undulations, and grooves for generating dynamic pressure with a depth of 3 to 50 μm are formed, and a hemispherical recess 70 is formed at a position on the rotation axis of the polygon mirror 52. is formed.

The recesses 57.63 and 64.70 are opposed to each other, and a small ball 71.72 of a hard material (ceramic or metal) is accommodated in the approximately spherical space formed by the recesses.

FIG. 6 is a horizontal sectional view at Δ-A in FIG. 5,
The permanent magnet 61 is disk-shaped, and has eight magnetic poles that are magnetized in an annular shape, and the outer periphery of the permanent magnet 61 is shaped like a mirror portion 62 . The portions that reflect the laser beam are the regular polygonal side portions 73 of the mirror portion 62, and each side is finished with a mirror surface with high reflectance. In FIGS. 5 and 6, the polygon mirror 5
When rotating the stator coil 5, the solenoid 69 is energized to slightly lift the suppression plate 58, and then the stator coil 5 is rotated.
Turn on the power to 4. The top surface of the stator coil 54 is provided with a speed detection circuit and a vi1 pole detection ratio detection circuit as in the previous embodiment, so that a drive control device (not shown) receiving the output signals from these circuits selects the optimum coil. is energized, and the polygon mirror 52 rotates at a desired rotation speed. Here, the power supply to the solenoid 69 is cut off before the rotation speed of the polygon mirror 52 reaches the rated rotation speed, so that the polygon mirror 52 (and the spring 6
8, the pressing plate 58 rotates in a pressed state and in a state in which a fluid film is formed at the sliding portion between both ends of the polygon mirror 52 in the direction of the rotation axis.

In this embodiment, the vibration of the polygon mirror 52, which is a rotor, in the rotational axis direction is suppressed by the damping effect of the fluid film formed on both surfaces of the polygon mirror 52.

In addition, since the mirror portion 62 of the polygon mirror 52 is a regular polygon that is almost inscribed in the outer periphery of the upper and lower rotation side sliding plates 59 and 60, when handling the polygon mirror 52, the mirror portion 62 may be contaminated. Never.

7 and 8 are embodiments related to the third aspect of the present application, in which FIG. 7 is a longitudinal cross-sectional view of the polygon mirror driving device, and FIG. 8 is a horizontal cross-sectional view taken along section B-8 in FIG. FIG. In FIG. 7, parts common to those in FIG. 5 are given the same numbers, and similar parts are given numbers with l'-100J added.

Referring to FIG. 7, a cap 51 is screwed to the support base 50, and an end 76 of a fixed shaft 74 made of a hard ceramic material is fitted into the central through hole 75.
It is fixed. A stator coil 54 is arranged in an annular manner on the outside of the fixed shaft 74, and the stator coil 54 is also fixed to the support base 50 by adhesive or known fastening means. A fixed side bearing 155 made of an annular disk made of a hard ceramic material is fixed to the upper surface of the stator coil 54, that is, the surface facing the polygon mirror 152, and the surface of the fixed side bearing facing the polygon mirror 152 has little undulation. It is finished to have a smooth surface, and grooves with a depth of 3 to 50 μm for generating dynamic pressure are formed. Further, the surface of the stationary side bearing and the axis of the stationary shaft 74 are fixed to be perpendicular to each other as much as possible.

The polygon mirror 152 has rotation side sliding surfaces formed on both end faces in the direction of the rotation axis, and the upper rotation side! Behavior board 1
60 and the lower rotating side sliding plate 159 are each made of a hard ceramic material, especially the lower rotating side 1 sliding plate 15.
9 is integrated with the rotating sleeve 79 of the polygon mirror 152. The inner peripheral surface of the rotating sleeve 79 is a smooth cylindrical surface, and the stator coil 54 of the rotating side sliding plate 159
The perpendicularity with the facing surface is well maintained. Also, the rotating sleeve 79 of the polygon mirror 152 of the fixed eA74
A groove 80 for generating dynamic pressure is formed in a portion corresponding to . The groove depth of this herringbone-shaped groove 80 is 3 to 15
Roughly speaking, it is desirable that the clearance between the fixed shaft 74 and the rotating sleeve 79 be in the range of 2 to 3 μm on each side.

The fluid film for supporting the radial load formed by the relative rotational movement between the fixed shaft 74 and the rotating sleeve 79 is preferably maintained as well as the parallelism of the 18 moving surfaces between the fixed shaft 74 and the rotating sleeve 79. Although it is formed in Sarel,
In this embodiment, since the length of the rotating sleeve 79 of the polygon mirror 152 (substantially equal to the thickness of the polygon mirror 152) is short, machining of the outer circumferential surface of the fixed shaft 74 and the inner circumferential surface of the rotating sleeve 79 is difficult. This method is easier than the conventional example and can achieve higher machining accuracy.

Note that the mirror part 62 that constitutes the polygon mirror 152,
After the upper rotating side sliding plate 160, the permanent magnet 161, and the lower rotating side sliding plate 159 (including the rotating sleeve 79) are glued together, the upper and lower rotating side sliding plates are made to have good parallelism. Polish the surface of the upper rotating side sliding plate 160 as much as possible,
Furthermore, the balance has been adjusted.

FIG. 8 shows the B-B111fi plane of FIG. 7, and the permanent magnet 161 is annularly magnetized with eight magnetic poles, and the outer periphery of the mirror portion 62 has a regular octagonal shape.

FIG. 9 shows the pattern of the sliding surface of the stationary bearing 155 fixed to the upper surface of the stator coil 54.

An arrow 81 indicates the rotation direction of the polygon mirror 152;
2 is a through hole through which the fixed shaft 74 passes. Fixed side bearing 1
On the surface of 55, spiral grooves 83 for generating dynamic pressure, which are shown in black, and similarly spiral lands 84 are formed alternately over the entire circumference, and the inner peripheral end of 83 is equalized by pressure equalizing grooves 85.
are in contact with each other. Roughly speaking, the inner peripheral side of the pressure equalizing groove 85 is a land 86. Lands 84 and 86 lie on the same plane.

Therefore, when the polygon mirror rotates in the direction of arrow 81, the surrounding fluid (air) receives a force from the outer circumferential side to the inner circumferential side of the spiral groove 83, and dynamic pressure of the fluid is generated in the sliding part. .

FIG. 10 shows an example of a groove for generating dynamic pressure suitable for a polygon mirror for high-speed rotation, when it is formed on the rotation side sliding surface. Arrow 87 is the rotation direction of the polygon mirror,
A through hole 89 through which a fixed shaft passes is formed in the center of the rotating side sliding plate 88, and an inner circumferential surface 90 of the n through hole 89 forms a rotating side sleeve. A spiral groove 91 (black portion) for generating dynamic pressure is formed on the surface of the rotating side sliding plate 88, and an adjacent land 924 is also finished to have a smooth surface. Furthermore, the outer peripheral edge 93 of the rotating side sliding plate 88 also forms a continuous land d3 over the entire circumference. When the polygon mirror rotates in the direction of the arrow 87, the centrifugal force of the spiral groove 91 causes the fluid to The fluid flows from the inner circumferential side toward the outer circumferential side, and the fluid pressure is contained by the land 93 surrounding the outer circumference. Therefore, a large dynamic pressure is generated on the outer periphery of the spiral groove 91.

When using the type of groove pattern for generating dynamic pressure shown in FIG. 10, the fluid flows from the center to the outer periphery, so that It is necessary to form a pressure equalization path in the center that communicates with the atmosphere on the outer peripheral side so that fluid can be replenished.

[Effects] The present invention provides a dynamic pressure bearing in the form of a flat plate made of ceramic material of vlM in the 1a moving part between the rotor and the stator in an electric VJ machine region in which the stator is disposed facing the end face in the direction of the rotational axis of the rotor. 1. A small and light electric machine with a long life can be constructed.

2. The thrust bearing has improved wear resistance and corrosion resistance, making maintenance easier.

3. It can be used in both liquid and gas environments, and even in slurry.

4. The length of the thrust bearing is perfect! ! Friction resistance is 0
．． 001 or less, and the loss of power in the bearing is extremely small.

5. A flat motor can be created.

6. By fixing functional members such as wings and reflectors to the rotor or configuring them to be integrated with the rotor, various electric machines can be mounted with a simple structure. 7. On both end faces of the rotor in the direction of the rotation axis, Since each is equipped with a dynamic pressure bearing made of a hard ceramic material, the rotor rotates under the damping effect of both sliding surfaces, and the runout of the rotor is extremely small. In addition, 8. The radial bearing, which is composed of a mother hole formed in the center of the rotor and a fixed shaft inserted through this zero hole, has a short length in the direction of the rotational axis, so it is difficult to process it. It has good accuracy and a large dynamic pressure effect of 1q.

9. Also, radial bearings can be easily machined without any force.

10. If the thrust bearings formed on both end faces of the rotor in the rotation axis direction are so-called pump-in type gjJL king bearings that push fluid from the outer circumference toward the inner circumference,
The pressure of the fluid in the radial bearing increases, and the dynamic pressure effect in the radial bearing becomes larger.

11. If one of the thrust bearings formed on both end faces of the rotor in the direction of the rotational axis is of the pump-in type and the other is of the pump-out type, a unidirectional flow will occur in the fluid interposed in the sliding part, and the stator coils will flow in one direction. Ya! Cooling of the learning area can be done.

12. If the above method 10 is adopted, the rotor can be housed in a sealed container with reduced pressure, and the air resistance of the polygon mirror can be reduced.

There are various effects such as

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, FIG. 2 is a partially enlarged view of FIG. 1, FIG. 3 is a partially enlarged view of FIG. 1, and FIG. 4 is another embodiment of the present invention. Fig. 5 is a longitudinal sectional view of another embodiment of the present invention, Fig. 6 is a sectional view taken along line AA in Fig. 5, and Fig. 7 is a longitudinal sectional view of another embodiment of the present invention. 8 is a sectional view taken along line B-8 in FIG. 7, FIGS. 9 and 10 are other embodiments of the portion shown in FIG. 7, and FIG. 11 is a conventional example. In the drawing, 3...fixing plate 4...coil 6...
Fixed plate 7...Small ball 8...Bearing surface
9...Rotating side sliding surface 10...Rotor 15...Spiral groove 100...Ceramics plate Patent applicant Ebara Research Institute, Ltd. Ebara Corporation (4 others) Figure 3, Figure 6 Figure 8 Figure 9 Figure 10 Figure 3+5 92 Figure 11

Claims (14)

[Claims] (1) In an electric machine in which a stator is disposed opposite to an end face of the rotor in the rotational axis direction, a rotating side sliding surface is formed on the end face of the rotor facing the stator, and the rotating side sliding surface is opposed to the rotating side sliding surface. The stator surface is a fixed-side bearing surface, the rotating-side sliding surface and the fixed-side bearing surface are each made of a hard ceramic material, and either one of the rotating-side sliding surface and the fixed-side bearing surface An electric machine characterized in that one surface is a flat surface and the other surface is a flat surface with grooves for generating dynamic pressure. (2) A recess is formed at a position on the axis of rotation of each of the rotating side sliding surface and the stationary side bearing surface, and two opposing surfaces are formed.
The electric motor according to claim (1), wherein a hard member that supports the rotating side sliding surface and the stationary side bearing surface so as to be able to rotate relative to each other is accommodated in the space formed by the two recesses. machine. (3) The ceramic material used for the fixed side bearing surface is β-SiC, BeO-containing α-SiC or Si
The electric machine according to claim (1) or (2), which is any one of _3N_4. (4) Rotation-side sliding surfaces are formed on both end faces of the rotor in the direction of the rotation axis, and the stator is disposed facing one rotation-side sliding surface, and the stator is arranged opposite to the other rotation-side sliding surface. In an electric machine having a movable bearing surface, the surface of the stator opposite to the rotating side sliding surface is a stationary side bearing surface, and the two rotating side sliding surfaces and the two bearing surfaces opposite thereto are Each is made of hard ceramic material, and
A groove for generating dynamic pressure is provided on one of two surfaces constituting the sliding portion formed by both end surfaces in the direction of the rotor's rotational axis, and the other surface is a smooth flat surface. electric machine. (5) A recess is formed at a position on the axis of rotation of each of the fixed side bearing surface and the rotating side sliding surface opposing thereto, and the fixed side bearing surface is provided in the space formed by the two opposing recesses. The electric machine according to claim 4, further comprising a hard member that supports the rotary side sliding surface and the rotary side sliding surface so as to be able to rotate relative to each other. (6) Claim No. 4, wherein the ceramic material used for the stationary side bearing surface is either α-SiC containing BeO, Si_3N_4, or β-SiC.
The electric machine described in paragraph or paragraph (5). (7) The electric machine according to any one of claims (4) to (6), wherein a polygon mirror is provided on the outer peripheral surface of the rotor. (8) Rotation-side sliding surfaces are formed on both end faces of the rotor in the direction of the rotation axis, and the stator is disposed opposite to one rotation-side sliding surface, and the stator is arranged to swing opposite to the other rotation-side sliding surface. In an electric machine having a movable bearing surface, a fixed shaft extending on the rotational axis of the rotor is fixed to the stator, and a through hole is formed in the center of the rotor corresponding to the fixed shaft. A radial bearing, the surface of the stator opposite to the rotating side sliding surface is a fixed side bearing surface, and the two rotating side sliding surfaces and the two opposing thereto
Each of the two bearing surfaces is made of a hard ceramic material, and a groove for generating dynamic pressure is provided on one of the two surfaces forming the sliding part formed on both end surfaces in the direction of the rotor's rotational axis. , an electric machine characterized in that the other surface is a smooth plane. (9) The fixed shaft and the radial bearing are each made of a hard ceramic material, and a groove for generating dynamic pressure is formed on one of the surfaces.
) Electric machines listed in section 2. (10) The fixed shaft passes through the through hole of the rotor over both ends thereof.
The electric machine described in section 9). (11) The hard ceramic material is SiC, Si_
3N_4. The electric machine according to claims (8) to (10). (12) The electric machine according to any one of claims (8) to (11), wherein a polygon mirror is provided on the outer peripheral surface of the rotor. (13) Claims (8) to (12) in which a rotor position detection element is fixed to the fixed side bearing surface.
) Electric machines listed in section 2. (14) A magnetic body is fixed at a position corresponding to the position detection element on the rotating side sliding surface facing the stationary side bearing surface,
In addition, claim No. 2 is magnetized with a large number of magnetic poles.
13) The electric machine described in item 13).