JPH0965603A - Motor structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive motor structure which can prevent the run-out of the shaft of a rotating body by suppressing the unstable revolution of the rotating body with a simple structure. SOLUTION: A weight 37 or projection is provided on the upper surface or outer periphery of a back yoke 35 which is positioned on an extension line drawn from the position of the center of gravity G of a rotor assembly 23 perpendicularly to the axis of rotation R of the rotor assembly 23 passing through the center of gravity G.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor structure provided in a high-speed rotation driving member such as a polygon mirror or a hard disk drive, and more particularly to a motor structure having a thrust bearing and a radial bearing which are slide bearings.

[0002]

2. Description of the Related Art Generally, a motor provided in a member that rotates at a high speed such as a polygon mirror or a hard disk drive is designed to suppress unstable turning of a rotating body.
It is known to make various improvements to the bearing structure, and as such a bearing structure, there is one as shown below.

As shown in FIG. 5, a rotary shaft 3 is inserted into a sleeve 2 which is provided on the inner peripheral portion of a hollow cylindrical housing 1 and has an inner diameter of a perfect circle, and a feed passage 1a for the housing 1 and the sleeve 2 is provided. 2a through the supply pipe 4 to the rotating shaft 3
By supplying compressed air to one side surface of the rotary shaft 3 to eccentrically rotate the rotary shaft 3, the rotary shaft 3 is stably rotated.

As shown in FIGS. 6 (a) and 6 (b), the inner peripheral surfaces of the sleeves 5 and 7 have an elliptical structure composed of two or three arc surfaces, and the rotary shaft 6 is provided in the sleeves 5 and 7. , 8 are inserted and the rotating shafts 6 and 8 are eccentrically rotated to rotate the rotating shafts 6 and 8 stably,
As shown in FIG. 6C, four tilting pads 10 are provided on the inner peripheral surface of the sleeve 9, and the tilting pad 10 is automatically adjusted according to the eccentricity of the rotary shaft 11, so that the rotary shaft 11 is rotated. Stable rotation.

As shown in FIG. 7, the sleeve 12 has a thickness of several μm.
The rotary shaft 13 having the dynamic pressure generating groove 13a having a width of several tens of μm is inserted, and the dynamic pressure generating groove 13a is rotated as the rotary shaft 13 rotates.
While pushing in the air in the direction of rotation of the rotary shaft 13, the sleeve 12
The rotary shaft 13 is stably rotated by scraping it out into the bearing gap between the rotary shaft 13 and the rotary shaft 13 to generate dynamic pressure.

As in the polygon scanner motor shown in FIG. 8, the radial bearing surface of the fixed shaft 14 has several μm to several tens μm.
And a rotary member 16 having a polygon mirror 15 is mounted on the fixed shaft 14, and the air in the dynamic pressure generating groove 14a is rotated as the rotary member 16 rotates. In order to rotate the rotating member 16 in a stable manner by pushing out in the bearing gap between the inner peripheral surface of the rotating member 16 and the fixed shaft 14 while pushing in the rotating direction of the rotating member 16 (such a polygon For the scanner motor, see, for example, Japanese Patent Laid-Open No. 6-129430).

[0007]

However, in the bearing structure shown by, since the compressed air is blown to the rotary shaft 3 to eccentrically rotate the rotary shaft 3, the supply pipe 4 is provided. In addition, the structure is complicated because the supply passages 1a, 2a, etc. must be provided, and a supply device for supplying air to the supply passages 1, 2 is required outside, so that the structure itself becomes large. The problem of being lost has occurred.

Further, in the case of (a) and (b), since the sleeves 5 and 7 must be formed with arcuate surfaces, the structures of the sleeves 5 and 7 are complicated and the manufacturing cost thereof is increased. have done. Further, in the structure shown in (c), the structure for displacing the center of curvature of each tilting pad 10 from the bearing surface becomes complicated, and the rotating shaft 11
The mechanism for automatically adjusting the tilting pad 10 in accordance with the eccentricity becomes complicated, and the manufacturing cost thereof becomes very high.

In addition, in the one shown in, the rotating shaft
Micron-order dynamic pressure generating groove 13a on 13 and fixed shaft 14
Since the dynamic pressure generating groove 14a must be formed,
Since the machining is troublesome and an expensive machining device for machining the grooves 13a and 14a with high accuracy is required, the rotary shafts 13 and 14 can be machined.
In addition to increasing the manufacturing cost of the bearing, if the bearing surface is made of resin with good wear resistance, the bearing will be significantly worn at the dynamic pressure generation part, shortening the service life. Has occurred.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a low-cost motor structure capable of suppressing unstable turning by a simple structure to prevent shaft runout of a rotating body.

[0011]

According to the first aspect of the present invention,
In order to solve the above problems, a rotating body having a field magnet and a fixed body having a coil substrate having a plurality of drive coils fixed to face the field magnet are provided.
In a motor structure in which a rotating body is rotatably supported on a fixed body via a radial bearing and a thrust bearing, the radial bearing is constituted by a cylindrical shaft and a sliding bearing that houses the shaft and has a cylindrical hollow shaft having an inner diameter. A weight is provided on the rotating body, and the weight is located on an extension line orthogonal to the position of the center of gravity G with respect to the rotation axis of the rotating body passing through the center of gravity G of the rotating body.

In this case, a centrifugal force acts on the rotating body by the weight while the rotating body rotates about the rotating axis, and the rotating axis of the rotating body moves parallel to the central axis of the fixed body through the thrust bearing. Then, the rotation axis of the rotating body is eccentrically rotated with respect to the central axis of the fixed body. As a result, the rotating body does not turn unstablely, the shaft shake of the rotating body does not occur, and the vibration due to the turning does not occur. Further, instead of the complicated bearing having the dynamic pressure generating groove and the elliptical structure as in the conventional case, the rotating body can be prevented from rotating by the sliding bearing having the simple structure, so that the structure of the motor becomes complicated. And the cost can be reduced.

In order to solve the above-mentioned problems, the invention as set forth in claim 2 includes a rotating body having a field magnet, and a fixed coil substrate having a plurality of drive coils fixed to the field magnet. In a motor structure in which a rotating body is rotatably supported by a fixed body via a radial bearing and a thrust bearing, the radial bearing comprises a cylindrical shaft and a hollow shaft having an inner diameter of a cylinder that houses the shaft. It is constituted by a slide bearing, and the rotary body is provided with a blade-shaped projection, and the projection is positioned on an extension line orthogonal to the position of the center of gravity G with respect to the rotation axis of the rotary body passing through the center of gravity G of the rotary body. I am trying.

In this case, while the rotating body rotates about the rotation axis, the blade-like projection receives wind pressure and acts as a centrifugal force, so that the rotation axis of the rotating body moves through the thrust bearing to the center of the fixed body. It moves parallel to the axis, and the rotation axis of the rotating body is eccentrically rotated with respect to the central axis of the fixed body. As a result, the rotating body does not turn unstablely, the shaft shake of the rotating body does not occur, and the vibration due to the turning does not occur. Further, instead of the complicated bearing having the dynamic pressure generating groove and the elliptical structure as in the conventional case, the rotating body can be prevented from rotating by the sliding bearing having the simple structure, so that the structure of the motor becomes complicated. And the cost can be reduced.

In order to solve the above-mentioned problems, the invention according to claim 3 is the invention according to claim 1 or 2, wherein the shaft is provided on either the fixed body side or the rotating body side, and the hollow shaft is provided. It is provided on either the fixed body side or the rotating body side, and the shaft is made of metal and the hollow member is made of lubricating resin.

In this case, by forming the hollow member from a resin that is easier to process than metal, the processing time of the hollow member is shortened and the manufacturing cost of the motor structure is reduced. When both the shaft and the hollow member are made of metal, it is necessary to provide a lubricating fluid film between the shaft and the hollow member in order to prevent seizure that occurs when the shaft and the hollow member come into contact with each other.
Since the hollow member is made of a lubricating resin, it is not necessary to provide a lubricating fluid film, oil is prevented from scattering, and the surroundings are not contaminated.

When a hollow member made of a lubricating resin is provided on the rotor side, the rotor is made lighter by the amount of the resin hollow member, the load applied to the hollow member is reduced, and the motor structure is long. It will have a lifetime. According to a fourth aspect of the present invention, in order to solve the above-mentioned problems, in the first or second aspect of the invention, the shaft is provided on either the fixed body side or the rotary body side, and the hollow shaft is fixed body side or It is characterized in that it is provided on the other side of the rotating body, the shaft is made of any material of stainless steel, aluminum, brass, and steel, and the hollow member is made of a polyimide resin.

In this case, the hollow member is made of a polyimide resin, and the shaft is made of stainless steel having good compatibility with polyimide.
Since it is made of any one of aluminum, brass, and steel, it is possible to obtain a motor structure that is excellent in heat resistance and wear resistance and that can be used for a long time even in a high temperature environment. Further, since the coefficient of thermal expansion of polyimide resin is smaller than that of other resins, it is possible to ensure shaft runout accuracy in a wide temperature range and good creep properties, so that even if the shaft and hollow member come into contact during high-speed rotation. A bearing structure does not occur and a highly reliable motor structure can be obtained.

Further, since the polyimide resin has excellent machinability, it is molded by injection molding or the like and the productivity of the hollow member is improved. Therefore, the hollow member is low in cost, and as a result, the manufacturing cost of the motor structure is further reduced. Furthermore, if a hollow member made of a polyimide resin is provided on the rotating body side, the rotating body is reduced in weight by the amount of the resin hollow member, and the load applied to the hollow member is reduced,
The motor structure has a long life.

According to a fifth aspect of the invention, in order to solve the above-mentioned problems, in the invention according to any one of the first to fourth aspects,
The thrust bearing is composed of a thrust plate made of a polyimide resin that is in sliding contact with the axial end of the shaft, the shaft is provided on the fixed body side, and the hollow shaft and the thrust plate are built in on the rotation center side of the rotating body. It is characterized by that.

In this case, since both the hollow member forming the radial bearing and the thrust plate forming the thrust bearing are made of polyimide resin, the weight of the rotor is further reduced and the load applied to the hollow member is further reduced. , The motor structure will have a much longer life. Further, in addition to the hollow member, the thrust plate is also made of polyimide resin, so that heat resistance and wear resistance are further improved, and a motor structure that can be used for a longer period of time even in a high temperature environment can be obtained.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on Examples. 1 to 3 are diagrams showing a first embodiment of a motor structure according to the present invention and correspond to the invention described in any one of claims 1, 3, 4, and 5. In this embodiment, the motor structure is applied to a polygon scanner motor.

First, the configuration will be described. In FIG. 1, 21
Is a polygon scanner motor, and this motor 21 includes a stator assembly 22 fixed to a base 24 and a rotor assembly 23 axially assembled to the stator assembly 22.
It is composed of The base assembly 22 constitutes a fixed body, and includes a boss 25, a fixed shaft 26, a coil substrate 27, and a flat coil (driving coil) 28. boss
25 is fitted to the base 24, and a cylindrical fixed shaft 26 is vertically fitted and fixed to the boss 25. The fixed shaft 26 is made of any one of stainless steel, aluminum, brass and steel.

A coil board 27 is attached to the outer periphery of the upper portion of the boss 25, and the coil board 27 is a base.
It extends parallel to 24. The flat coil 28 is disposed on the coil substrate 27 and includes, for example, a predetermined number of coreless armature coils, and the armature coils do not overlap each other in the magnetic path of the field magnet described later. The openings are provided at regular intervals with a predetermined angle. In addition, the coil board 27
A control circuit 29 is attached to the control circuit 29, and the control circuit 29 excites the coil 28 to drive and control the scanner motor 21.

The rotor assembly 23 constitutes a rotating body, and includes a flange 30, a polygon mirror 31, and a sleeve.
32, a thrust bearing 33, a rotor magnet (field magnet) 34, and a back yoke 35.
A polygon mirror 31 is attached to the outer peripheral portion of the flange 30, a hollow shaft-shaped sleeve 32 is attached to the inner peripheral surface, and a thrust bearing 33 made of a thrust plate is attached to the upper opening portion. Also, the sleeve 32 has an inner peripheral surface.
32a forms a sliding surface that serves as a radial bearing, and this sleeve 32 is made of a lubricating resin.

Further, as is apparent from FIG. 1, the sleeve 32
And the thrust bearing 33 is built in on the rotation center side of the rotor assembly 23. Therefore, the flange 32 and the polygon mirror 31 are rotatably supported by the fixed shaft 26 via the sleeve 32 and the thrust bearing 33. The back yoke 35 is attached to the lower portion of the flange 30, and the rotor magnet 34 is attached to the lower surface of the back yoke 35 so as to be substantially parallel to the back yoke 35. The rotor magnet 34 rotates when excited by the coil 28, and the back yoke 35, the housing 30, and the polygon mirror are rotated as the rotor magnet 34 rotates.
31 is designed to rotate integrally.

On the other hand, an annular projecting portion 35a is bent on the outer peripheral portion of the back yoke 35, and the projecting portion 35a extends parallel to the rotation axis R of the rotor assembly 23. A weight 37 is provided on the upper surface of the back yoke 35 near the protrusion 35a, and the position where the weight 37 is arranged passes through the center of gravity G of the rotor assembly 23 and the rotation axis R of the rotor assembly 23.
On the other hand, it is set on an extension line orthogonal to the position of the center of gravity G.

That is, in this embodiment, the rotor assembly 23
Back yoke 35 when assembling the
Of the rotor rotor 23 whose upper surface passes through the center of gravity G of the rotor assembly 23.
A back yoke 35 is arranged so as to coincide with an extension line orthogonal to the rotation axis R of the center of gravity G, and a weight 37 is attached to the outer peripheral portion of the back yoke 35. next,
The operation will be described.

When current is sequentially supplied to the predetermined drive coils 28 facing each other by the control circuit 29, the predetermined coils 28 facing each other are excited and the rotor assembly 23 is sleeved.
It rotates with respect to the fixed shaft 26 via 32 and the thrust bearing 33. Here, in a general scanner motor having a perfect circular bearing, the rotor assembly 23 makes an unstable turn, resulting in an increase in shaft runout, and for a scanner motor that requires shaft runout accuracy on the order of microns. It becomes a serious problem, and such runout is especially caused by the fixed shaft of the stator assembly 22.
This occurs when the amount of eccentricity of the rotation axis of the sleeve 32 of the rotor assembly 23 with respect to the center axis of 26 is small.

This will be described with reference to FIG. 2. As shown in FIG. 2A, the rotation axis C1 of the rotor assembly 23 is
To match the central axis C2 of the fixed shaft 26, or
As shown in FIG.
This can be suppressed by largely eccentricity from the central axis C2 of 6 by the amount of eccentricity Emax, but it is difficult to match the axes C1 and C2 with each other as shown in FIG. The method as shown in FIG.

That is, by providing the weight 37 on the outer peripheral portion of the back yoke 35 located on the extension line orthogonal to the position of the center of gravity G with respect to the rotation axis R of the rotor assembly 23 passing through the center of gravity G of the rotor rotor 23, The rotor assembly 23 has a rotation axis R
The weight 37 causes the rotor assembly 23 to
The centrifugal force acts on the rotor assembly 23 as shown in FIG.
Rotation axis C1 (R) of the rotor assembly 23 moves in parallel to the center axis C2 of the fixed shaft 26, and the rotation axis C1 of the rotor assembly 23 rotates eccentrically to the center axis C2 of the fixed shaft 26. To do. As a result, it is possible to prevent the rotor assembly 23 from swinging in an unstable manner, prevent the shaft shake of the rotor assembly 23 from occurring, and prevent the vibration due to the swing. it can.

Further, instead of a complicated bearing having a dynamic pressure generating groove or an elliptical structure as in the conventional case, a sliding bearing having a simple structure can prevent the rotor assembly 23 from rotating, so that the motor The structure of 21 can be prevented from becoming complicated, and the cost thereof can be reduced. Further, in the present embodiment, the fixed shaft 26 is made of any metal of stainless steel, aluminum, brass, and steel, and the sleeve 32 is made of a lubricating resin, so that the processing of the sleeve 32 is facilitated. The processing time of the sleeve 32 can be shortened, and the manufacturing cost of the motor 21 can be reduced. Further, when both the fixed shaft 26 and the sleeve 32 are made of metal, the fixed shaft 26 and the sleeve 32 are prevented from being burned when the fixed shaft 26 and the sleeve 32 come into contact with each other.
Although it is necessary to provide a lubricating fluid film between 32, in this embodiment, since the sleeve 32 is made of a lubricating resin, it is not necessary to provide a lubricating fluid film and oil scattering is prevented. It is possible to prevent the surroundings from becoming dirty.

Further, since the sleeve 32 made of a lubricating resin is provided on the rotating side, the rotor assembly 23 is made of a resin sleeve.
The weight of 32 can be reduced to reduce the load applied to the sleeve 32, and the motor 21 can have a long life. In the present embodiment, the sleeve 32 is made of a lubricating resin, but instead of this, it may be made of a polyimide resin. In this case, the sleeve 32 and stainless steel, aluminum, brass, or any of the materials have good compatibility, so it has excellent heat resistance and wear resistance, and can be used for a long time even in a high temperature environment. It is possible to obtain a different motor 21. Further, since the coefficient of thermal expansion of polyimide resin is smaller than that of other resins, it is possible to secure shaft runout accuracy in a wide temperature range and the creep property is also good, so the fixed shaft 26 and the sleeve 32 contact each other at high speed rotation. However, the bearing lock can be prevented from occurring, and the motor 21 with high reliability can be obtained.

Since the polyimide resin has excellent machinability, it can be molded by injection molding or the like,
The productivity of the sleeve 32 can be improved. Therefore, the sleeve 32 can be manufactured at low cost, and as a result, the manufacturing cost of the motor 21 can be further reduced. Further, even when the sleeve 32 is made of polyimide resin, the rotor assembly 23 can be made lighter by the amount of the resin sleeve 32 to reduce the load applied to the sleeve 32, and the motor 21 can have a long life. be able to.

Further, when this aspect is adopted, the thrust bearing 33 may also be made of polyimide. With this configuration, the sleeve 32 and the thrust bearing 33 that form the radial bearing are both made of polyimide resin, so that the rotor rotor 23 can be made even lighter and the load applied to the sleeve 32 can be further reduced. The motor 21 can have a much longer life.

In addition to the sleeve 32, the thrust bearing 33
By using a polyimide resin, the heat resistance and wear resistance can be further improved, and the motor 21 that can be used for a longer period of time even in a high temperature environment can be obtained. In this embodiment, the polygon scanner motor 21 is configured such that the rotor assembly 23 is rotated with respect to the stator assembly 22 having the fixed shaft 26 to be fixed. A polygon mirror is installed on the 26 side,
It is needless to say that the invention can be applied to a polygon scanner motor of the type in which the rotor assembly 23 side is fixed.

FIG. 4 is a diagram showing a second embodiment of the motor structure according to the present invention and corresponds to the invention described in any one of claims 2 to 5. The present embodiment is characterized in that a blade-like projection is provided on the outer peripheral portion of the back yoke in place of the weight. The same components as those in the above-mentioned embodiment are designated by the same reference numerals and the description thereof will be omitted. In FIG. 4, a blade-shaped protrusion 40 is attached to the outer peripheral surface of the protruding portion 35a formed on the outer peripheral portion of the back yoke 35, and the position where this protrusion 40 is arranged is the center of gravity G of the rotor assembly 23. Axis of rotation R of the rotor assembly 23 passing through
On the other hand, it is set on an extension line orthogonal to the position of the center of gravity G.

In this embodiment, when the control circuit 29 sequentially supplies currents to predetermined driving coils 28 facing each other,
A predetermined coil 28 facing each other is excited to rotate the rotor assembly 23 through the sleeve 32 and the thrust bearing 33 to fix the fixed shaft.
Rotate against 26. At this time, the projections 40 receive wind pressure and act on the rotor assembly 23 in a manner corresponding to centrifugal force. As shown in FIG. 3, the rotation axis C1 (R) of the rotor assembly 23 is the central axis of the fixed shaft 26. The rotor assembly 23 moves parallel to and moves parallel to C2, and the rotation axis C1 of the rotor assembly 23 rotates eccentrically to the center axis C2 of the fixed shaft 26. As a result, it is possible to prevent the rotor assembly 23 from swinging in an unstable manner.
In addition to preventing shaft runout of 23,
It is possible to prevent vibration due to turning.

Further, instead of a complicated bearing having a dynamic pressure generating groove or an elliptic structure as in the conventional case, a sliding bearing having a simple structure can prevent the rotor assembly 23 from rotating, so that the motor It is possible to prevent the structure of 21 from becoming complicated, and it is possible to obtain the same effect as that of the other first embodiment that can reduce the cost. Further, in each of the above-described embodiments, it is possible to prevent the rotor assembly 23 from eccentrically rotating and causing shaft runout,
It is possible to obtain the effect of reliably preventing the polygon mirror 31 from falling over.

In each of the above embodiments, the motor structure is applied to the polygon scanner motor, but it is needless to say that the present invention is not limited to this and can be applied to all kinds of motor structures such as a hard disk drive motor. .

[0041]

According to the invention described in claim 1, when the rotating body rotates about the rotation axis, a centrifugal force can be applied to the rotating body by the weight, and the rotation axis of the rotating body can be used as a thrust bearing. It is possible to rotate the rotating body so that the rotation axis of the rotating body is eccentric with respect to the center axis of the fixed body by moving the rotating body parallel to the center axis of the fixed body.

As a result, it is possible to prevent the rotating body from swinging in an unstable manner and to prevent the rotating body from swinging around the shaft, and also to prevent the vibration due to the swinging from occurring. Further, instead of the complicated bearing having the dynamic pressure generating groove and the elliptical structure as in the conventional case, the rotating body can be prevented from rotating by the sliding bearing having the simple structure, so that the structure of the motor becomes complicated. Can be prevented, and the cost can be reduced.

According to the second aspect of the present invention, when the rotating body rotates about the axis of rotation, the blade-shaped projections receive wind pressure and can give the rotating body an action equivalent to a centrifugal force. The rotation axis of the rotating body can be moved parallel to the center axis of the fixed body via the thrust bearing, and the rotation axis of the rotating body can be eccentrically rotated with respect to the center axis of the fixed body to rotate.

As a result, it is possible to prevent the rotating body from swinging in an unstable manner and to prevent the rotating body from swinging, and also to prevent vibration due to the swinging. Further, instead of the complicated bearing having the dynamic pressure generating groove and the elliptical structure as in the conventional case, the rotating body can be prevented from rotating by the sliding bearing having the simple structure, so that the structure of the motor becomes complicated. Can be prevented, and the cost can be reduced.

According to the third aspect of the present invention, by forming the hollow member from a resin that is easier to process than metal, it is possible to shorten the processing time of the hollow member and reduce the manufacturing cost of the motor structure. it can. When both the shaft and the hollow member are made of metal, it is necessary to provide a lubricating fluid film between the shaft and the hollow member in order to prevent seizure that occurs when the shaft and the hollow member come into contact with each other. By using a lubricative resin for the member, it is possible to eliminate the need to provide a lubricative fluid film, prevent the oil from scattering, and prevent the surroundings from becoming dirty.

When a hollow member made of a lubricating resin is provided on the rotor side, the rotor can be made lighter by the amount of the resin hollow member, and the load applied to the hollow member can be reduced to reduce the motor load. The structure can have a long life. According to the invention as set forth in claim 4, since the hollow member is made of a polyimide resin and the shaft is made of any material of stainless steel, aluminum, brass, and steel having good compatibility with polyimide, heat resistance and It is possible to obtain a motor structure that has excellent wear resistance and can be used for a long period of time even in a high temperature environment. Further, since the coefficient of thermal expansion of polyimide resin is smaller than that of other resins, it is possible to ensure shaft runout accuracy in a wide temperature range and good creep properties, so that even if the shaft and hollow member come into contact during high-speed rotation. Bearing lock can be prevented from occurring, and as a result, a highly reliable motor structure can be obtained.

Since polyimide resin has excellent machinability, it can be molded by injection molding,
The productivity of the hollow member can be improved. Therefore, the cost of the hollow member can be reduced, and as a result, the manufacturing cost of the motor structure can be further reduced. Furthermore, if a hollow member made of polyimide resin is provided on the rotor side, the rotor can be made lighter by the amount of the resin hollow member, the load applied to the hollow member is reduced, and the motor structure has a long life. Can be

According to the fifth aspect of the present invention, since the hollow member forming the radial bearing and the thrust plate forming the thrust bearing are made of polyimide resin, the rotating body can be made even lighter and added to the hollow member. The load can be further reduced, and the motor structure can have a longer life. Further, in addition to the hollow member, the thrust plate is also made of a polyimide resin, so that the heat resistance and wear resistance can be further improved, and a motor structure that can be used for a long time even in a high temperature environment is provided. Obtainable.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of a motor structure according to the present invention, and is a cross-sectional view of a polygon scanner motor to which the motor structure is applied.

FIG. 2A is a view showing a state in which the rotor assembly is rotated by aligning the rotation axis C1 of the rotor assembly with the central axis C2 of the fixed shaft, and FIG. 2B is a view showing the rotation axis C1 of the rotor assembly fixed. FIG. 9 is a diagram showing a state in which the rotor assembly is rotated with a large amount of eccentricity Emax from the central axis C2 of the shaft.

FIG. 3 is a diagram showing a state in which a sleeve of the polygon scanner motor is eccentric to a fixed shaft.

FIG. 4 is a diagram showing a second embodiment of the motor structure according to the present invention, and is a sectional view of a polygon scanner motor to which the motor structure is applied.

FIG. 5 is a cross-sectional view of a conventional bearing member that blows compressed air onto a rotating shaft.

6A is a sectional view of a conventional elliptical bearing, FIG. 6B is a sectional view of a three-arc bearing, and FIG. 6C is a sectional view of a tilting pad bearing.

FIG. 7 is a sectional view of a conventional dynamic pressure generating bearing.

FIG. 8 is a sectional view of a polygon scanner motor having a conventional herringbone groove bearing.

[Explanation of symbols]

 21 Polygon scanner motor (motor structure) 22 Stator assembly (fixed body) 23 Rotor assembly (rotary body) 26 Fixed shaft (radial bearing) 27 Coil board 28 Flat coil (drive coil) 32 Sleeve (radial bearing) 33 Thrust Bearing 34, 40 Rotor magnet (field magnet) 37 Weight 40 Projection

Claims (5)

[Claims] 1. A rotary body having a field magnet and a fixed body having a coil substrate on which a plurality of drive coils are fixed so as to face the field magnet, and the rotary body is provided with a radial bearing and a thrust bearing. In a motor structure that is rotatably supported on a fixed body via, the radial bearing is configured by a cylindrical shaft and a sliding bearing that houses the shaft and has a hollow shaft having a cylindrical inner diameter, and a weight is provided on the rotating body. The motor structure, wherein the weight is located on an extension line orthogonal to the position of the center of gravity G with respect to the axis of rotation of the body of rotation that passes through the center of gravity G of the body of rotation. 2. A rotating body having a field magnet, and a fixed body having a coil substrate on which a plurality of drive coils are fixed so as to face the field magnet, the rotating body being a radial bearing and a thrust bearing. In a motor structure rotatably supported on a fixed body via a cylindrical shaft, the radial bearing is constituted by a slide bearing having a hollow shaft having a cylindrical inner diameter and a hollow shaft having an inner diameter, and the rotor has a blade-shaped projection. The motor structure is characterized in that the protrusion is located on an extension line orthogonal to the position of the center of gravity G with respect to the axis of rotation of the rotor passing through the center of gravity G of the body of rotation. 3. The shaft is provided on either the fixed body side or the rotary body side, and the hollow shaft is provided on the other fixed body side or the rotary body side, and the shaft is made of metal and a hollow member is provided. The motor structure according to claim 1 or 2, wherein the motor structure is made of a lubricating resin. 4. The shaft is provided on either the fixed body side or the rotary body side, and the hollow shaft is provided on either the fixed body side or the rotary body side, and the shaft is made of stainless steel, aluminum, brass, and The motor structure according to claim 1 or 2, wherein the hollow member is made of a polyimide resin while being made of any material such as steel. 5. The thrust bearing is composed of a thrust plate made of a polyimide resin that is in sliding contact with the axial end of the shaft, the shaft is provided on the fixed body side, and the hollow shaft and the thrust plate are rotated by a rotating body. The motor structure according to claim 4, wherein the motor structure is built in on the center side.