JP2010039337A - Polygon mirror scanner motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of fixing a polygon mirror scanner motor on an equipment keeping the right angle accuracy when fixing the scanner motor on the equipment while securing the right angle accuracy between the shaft of the polygon mirror scanner motor of which the shaft is directly fixed on a mounting plate and the mounting plate. <P>SOLUTION: The circumference of a connecting part 116 on which a shaft 111 is fixed is projected to the side opposite to the side on which a stator core 112 is disposed from a mounting plate 108 which serves as a mounting part of the motor onto the equipment to form a swelling part 109 having a cylindrical envelope face coaxial with the shaft 111, and the swelling part 109 is used as a centering and positioning part of the optical box 120 of an LBP on which the polygon mirror scanner motor is mounted and the shaft 111 of the motor. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polygon mirror scanner motor provided with a hydrodynamic bearing device, and more particularly to a motor structure that can be easily and accurately mounted without deteriorating the axis tilt accuracy of the motor when fixed to an optical box. It is.

In recent years, polygon mirror scanner motors are required to be smaller, thinner, and lower in cost with the spread of LBP. At the same time, it is necessary to maintain high-precision performance with respect to rotational fluctuation (hereinafter referred to as jitter), noise, and surface tilt of the polygon mirror. Further, with the spread of LBP, it is desired to increase the speed or color of the LBP, and the polygon mirror scanner motor is also required to rotate at a higher speed of 30,000 to 50,000 min ⁻¹ .

At the time of high speed rotation of 30,000 to 50,000 min ^{−1, the} effect of the grinding motion on the hydrodynamic bearing portion is extremely large, and there is a problem that the bearing life is significantly reduced. As means for solving the above problems, a herringbone groove is formed on the inner periphery of the cylindrical portion of the rotor boss, and the rotor boss rotates around the fixed shaft to form a fixed shaft type hydrodynamic bearing, and the polygon mirror is formed on the rotor boss. By mounting between the two dynamic pressure grooves, the bearing structure is similar to the both-end support structure. As a result, it is difficult to generate a plowing motion, and it is possible to extend the bearing life by equally sharing the load between the bearing portions of the two dynamic pressure grooves. Furthermore, it is necessary to fix the fixing shaft with a high degree of perpendicularity with respect to the mounting plate to which the fixing shaft is attached, and hence the surface tilt accuracy of the mirror surface with high accuracy and sufficient securing strength.

As a polygon mirror scanner motor that is equipped with a hydrodynamic bearing device that secures the squareness between the shaft and the mounting plate and firmly fastened between the members, and can be made compact, thin, low cost, and high speed. A polygon mirror scanner motor has been proposed in which an iron circuit board that also serves as a circuit board is used as a mounting plate, and a shaft is fixed to a through hole formed in the center of the iron circuit board by laser welding. As a method, with the shaft held at a right angle to the motor mounting surface of the iron circuit board by a jig, the laser is irradiated simultaneously from multiple locations on the circumference while rotating the joint between the shaft and the iron circuit board. And fixed by welding. (For example, see Patent Document 1)
FIG. 5 shows a cross-sectional view of the polygon mirror scanner motor described in Patent Document 1.
In FIG. 5, reference numeral 201 denotes a rotor frame, and a rotor boss 202 is fixed to a hole formed at the center. A polygon mirror 203 is fixed to the rotor boss 202, and a rotor magnet 204 is fixed to the inner periphery of the rotor frame 201. The rotor part 200 is comprised by the above.

The circuit board 211 having a mounting portion for mounting the polygon mirror scanner motor to the apparatus is made of an iron substrate, and generates torque on the stator core 212 laminated with the magnetic material constituting the magnetic path of the rotor magnet 204 so as to face the rotor magnet 204. A stator assembly 210 is configured by mounting a winding assembly 214 around which a stator coil 213 is wound and a drive IC 215 for operating a polygon mirror scanner motor. A through-hole 216 is formed at the center of the circuit board 211, and a shaft 220 is inserted into the through-hole 216, and the joint between the shaft 220 and the through-hole 216 is laser-welded on the back side of the circuit board 211. It is firmly fixed. On the other hand, the rotor boss 202 is provided with a cylindrical portion 205 at the center, and herringbone grooves 206 are formed in the inner periphery of the cylindrical portion 205 so as to be separated from each other in the axial direction. It is inserted and filled with a lubricant between the shaft 220 to form a radial hydrodynamic bearing and pivotally supported. One of two herringbone grooves 206 is formed on the inner periphery of the cylindrical portion 205 corresponding to the portion of the rotor boss 202 where the polygon mirror 203 is fixed.

  In this state, as shown in FIG. 6A, the joint portion 217 where the through-hole 216 and the shaft 220 are in contact with each other is continuously irradiated with laser at two irradiation points 218 and rotated 180 degrees or more on the circumference. Rotate to the final irradiation point 219, and continuously weld all around by laser to fix.

FIG. 6B shows a cross-sectional view of a state where the shaft is fixed to the circuit board by laser welding, and FIG. 6C shows a plan view.
JP 2008-136261 A

  However, in the above-described conventional configuration, as shown in FIG. 7A, when mounted on the LBP optical box 301 on which the polygon mirror scanner motor is mounted, it protrudes to the back side of the circuit board 211 that is a mounting plate for the polygon mirror scanner motor. Further, the centering positioning of the optical box 301 and the polygon mirror scanner motor must be performed using the end 221 of the shaft 220. Due to the tightening torque of the fixing screw at the time of fixing to the optical box 301, a moment acts on the circuit board 211 and a force for moving the circuit board 211 in the lateral direction is generated. Due to this force, as indicated by an arrow in FIG. 7B, a lateral load is applied to the end 221 of the shaft 220 via the inner peripheral wall of the centering hole 302 formed in the optical box 301. As a result, there is a problem that the perpendicularity between the circuit board 211 and the shaft 220 changes.

  The present invention solves such a conventional problem, and in a polygon mirror scanner motor having a shaft directly fixed to a mounting plate (circuit board), a perpendicularity between the shaft and the mounting plate (circuit board) is obtained. It is an object of the present invention to provide a polygon mirror scanner motor that can attach a device with a polygon mirror scanner motor and a concentricity of the motor shaft with high accuracy while ensuring accuracy.

  In order to solve the above problems, the present invention is inserted into a rotor frame, a rotor magnet fixed to the inner periphery of the rotor frame, a rotor boss having a cylindrical portion fixed to the center of the rotor frame, and an outer periphery of the cylindrical portion of the rotor boss. A winding assembly comprising a stator core comprising a rotor portion comprising a polygon mirror placed on the rotor frame, and arranged to face the rotor magnet and having a magnetic material laminated thereon, and a stator coil wound around the stator core; A stator part configured by a circuit board and a mounting plate that holds the circuit board and has a mounting part to a device on which a motor is mounted, and the shaft is directly fixed at the center of the mounting plate; A dynamic pressure bearing is constructed by forming a dynamic pressure groove in one of the cylindrical parts of the rotor boss to generate dynamic pressure in the radial direction. In the polygon mirror scanner motor configured to pivotally support the cylindrical portion of the rotor boss by the shaft, the motor shaft is centered on a device on which the polygon mirror scanner motor is mounted. The polygon mirror scanner motor is provided with a positioning part fitted to the part on the mounting plate. The positioning portion is a protrusion having a cylindrical envelope surface concentric with the shaft.

The specific configuration of the protrusion is as follows:
A bottomed cylindrical bulging portion formed by protruding the periphery of the fixing portion for fixing the shaft of the mounting plate to the side opposite to the side where the stator core is disposed from the mounting plate.

・ A plurality of arc-shaped walls formed by cutting and raising the mounting plate from the side opposite to the side where the stator core is disposed around the fixing portion for fixing the shaft of the mounting plate. ・ Fixing for fixing the shaft of the mounting plate A plurality of protrusions formed by protruding from the mounting plate to the side opposite to the side on which the stator core is disposed around the portion. The side where the stator core is disposed from the mounting plate around the fixed portion that fixes the shaft of the mounting plate. A bottomed cylindrical bulge formed by protruding into the bottom.

  It is.

According to the first to fifth aspects of the present invention, in the polygon mirror scanner motor having a configuration in which the shaft is directly fixed to the mounting plate and the rotor portion is pivotally supported by the shaft, the outer periphery of the shaft and the gap are formed. By providing the mounting plate with a positioning portion that is concentric with the shaft and fits to the motor mounting centering portion of the device on which the polygon mirror scanner motor is mounted,
When a motor moving force is applied to the motor mounting plane due to rotational torque of screw tightening when the motor is mounted, this force is received by the positioning part, so no force is directly applied to the shaft. The centering positioning of the shaft of the polygon mirror scanner motor and the device can be performed while ensuring the accuracy of the perpendicularity to the polygon mirror scanner motor.

  In particular, according to the third aspect of the present invention, the bottomed cylinder is formed by protruding the periphery of the fixing portion for fixing the shaft of the mounting plate from the mounting plate to the side opposite to the side where the stator core is disposed. By adopting a bulging part in the shape, the positioning part can be made more rigid, so even if a large torque is applied when the motor is mounted, the positioning part will not be distorted and high-precision positioning and squareness accuracy will be maintained. be able to. In addition, since no opening is formed in the mounting plate, it is possible to prevent entry of foreign matter or the like into the motor, and it is possible to provide a highly reliable polygon mirror scanner motor.

  According to the invention of claim 4, the plurality of protrusions formed by projecting the positioning portion from the mounting plate to the side opposite to the side where the stator core is disposed around the fixing portion for fixing the shaft of the mounting plate. Even if the bulging part cannot be formed as a positioning part due to space restrictions, the cylindrical envelope surface concentric with the shaft can be dispersed by using the part. By forming, it has the effect that a device and a shaft can be positioned concentrically. In addition, since there is little influence on the shaft fixing portion of the mounting plate when forming the positioning portion, there is an effect that it becomes easy to maintain the squareness accuracy with high accuracy.

According to the fifth aspect of the invention, the positioning portion is formed by cutting and raising the positioning portion from the mounting plate to the side opposite to the side where the stator core is disposed around the fixing portion that fixes the shaft of the mounting plate. By using the arc-shaped wall portion, air can enter and exit from the positioning portion, so that the rotor frame can be cooled. Especially when rotating at high speeds of 30,000 to 50,000 min ⁻¹ , the heat generated from the stator coils and bearings becomes very large. Therefore, by actively cooling the inside of the rotor frame, it is possible to prevent a decrease in life due to temperature rise. In addition, it is possible to provide a highly reliable and long-life polygon mirror scanner motor.

  Next, the invention according to claim 6 is characterized in that the enveloping surface concentric with the shaft formed by protruding the periphery of the fixing portion where the positioning portion fixes the shaft of the mounting plate from the mounting plate to the side where the stator core is disposed. By having the bottomed cylindrical bulged portion, the bulged portion serving as the positioning portion is on the stator core side, so that the polygon mirror scanner motor can be thinned.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

(Embodiment 1)
The first embodiment of the present invention will be described below with reference to FIGS. 1 (a), 1 (b) and 1 (c).

FIG. 1A is a longitudinal sectional view of a polygon mirror scanner motor according to an embodiment of the present invention. FIG. 1B is a bottom view of the polygon mirror scanner motor according to the embodiment of the present invention.
In FIG. 1A, reference numeral 101 denotes a rotor frame, and a rotor boss 102 is fixed to a hole formed in the center. A polygon mirror 103 is fixed to the rotor boss 102, and a rotor magnet 104 is fixed to the inner periphery of the rotor frame 101. The rotor unit 100 is configured as described above. A mounting plate 108 having a mounting portion for mounting the polygon mirror scanner motor to the apparatus is made of a plated steel plate or the like, and a circuit board 107 is fixed on one side thereof. The circuit board 107 has a winding assembly 114 in which a stator coil 113 that generates torque is wound around a stator core 112 on which a magnetic material constituting the magnetic path of the rotor magnet 104 is laminated, and a polygon mirror. A driving IC (not shown) for operating the scanner motor is mounted to constitute the stator assembly 110. A through hole 115 is formed in the center of the mounting plate 108, and the shaft 111 is inserted into the through hole 115, and the joint portion 116 of the shaft 111 and the through hole 115 is laser-welded on the back surface side of the mounting plate 108. It is fixed more firmly.

  On the other hand, the rotor boss 102 has a cylindrical portion 105 at the center, and herringbone grooves 106 are formed in the inner periphery of the cylindrical portion 105 so as to be spaced apart from each other in the axial direction. It is inserted and filled with a lubricant between the shaft 111 to form a radial hydrodynamic bearing and pivotally supported. One of two herringbone grooves 106 is formed on the inner periphery of the cylindrical portion 105 corresponding to the portion of the rotor boss 102 where the polygon mirror 103 is fixed.

  The above, except that the circuit board 211 made of iron substrate of the polygon mirror scanner motor of the prior art disclosed in Patent Document 1 shown in FIG. The configuration is almost the same.

  In the present embodiment, the configuration of the prior art is greatly different from the above-described conventional technique in that the periphery of the connecting portion 116 (fixing portion) for fixing the shaft 111 of the mounting plate 108 is disposed on the side where the stator core 112 is disposed from the mounting plate 108. Is a point formed by projecting a bottomed cylindrical bulging portion 109 on the opposite side. The bulging portion 109 is formed to have a cylindrical envelope surface concentric with the shaft 111.

  FIG. 1C is a longitudinal sectional view showing a state in which the polygon mirror scanner motor according to the first embodiment is attached to the optical box 120 of the LBP.

  As shown in FIG. 1C, the LBP optical box 120 has a centering hole having a diameter slightly larger than the outer diameter of the bulging portion 109 formed by protruding from the mounting plate 108 of the polygon mirror scanner motor. A portion 121 is formed. Since the bulging portion 109 of the polygon mirror scanner motor is formed so as to have a cylindrical envelope surface concentric with the shaft 111, the bulging portion 109 of the polygon mirror scanner motor is formed in the centering hole of the optical box 120. By inserting it into the section 121, the positioning of the shaft 111 of the polygon mirror scanner motor and the optical box 120 can be centered.

  Here, due to the tightening torque of the fixing screw when the polygon mirror scanner motor is fixed to the optical box 120, a moment is applied to the mounting plate 108 to generate a force for moving the mounting plate 108 in the lateral direction. With this force, a lateral load is applied to the bulging portion 109 via the inner peripheral wall of the centering hole portion 121 formed in the optical box 120, but the shaft 111 is not directly affected.

  As a result, it is possible to prevent the perpendicularity between the mounting plate 108 and the shaft 111 from changing.

(Embodiment 2)
The second embodiment of the present invention will be described below with reference to FIGS. 2 (a), 2 (b) and 2 (c). FIG. 2A is a longitudinal sectional view of a polygon mirror scanner motor according to the second embodiment of the present invention. FIG. 2B is a bottom view of the polygon mirror scanner motor according to the second embodiment of the present invention. 2 (a) and 2 (b), the difference from the first embodiment shown in FIG. 1 (a) is that three protrusions are used instead of protruding the protruding portion 109 from the mounting plate 108. This is the point where the portion 117 is formed. This protrusion 117 is a cylindrical shape that circumscribes the three protrusions around the connecting portion 116 (fixing portion) that fixes the shaft 111 of the mounting plate 108 on the side opposite to the side where the stator core 112 is disposed. The envelope surface is formed so as to be concentric with the shaft 111.

  FIG. 2C is a longitudinal sectional view showing a state in which the polygon mirror scanner motor according to the second embodiment is attached to the optical box 120 of the LBP.

  As shown in FIG. 2 (c), the LBP optical box 120 has an outer diameter dimension of a cylindrical envelope surface circumscribing three projections 117 formed by protruding from the mounting plate 108 of the polygon mirror scanner motor. A centering hole 121 having a slightly larger diameter is formed. Since the cylindrical envelope surface circumscribing the three projections 117 of the polygon mirror scanner motor is formed to be concentric with the shaft 111, the three projections 117 are aligned with the center of the optical box 120. By inserting into the hole portion 121, the shaft 111 of the polygon mirror scanner motor and the optical box 120 can be centered and positioned.

  With this configuration, as in the first embodiment, when the polygon mirror scanner motor is fixed to the optical box 120, it is applied laterally via the inner peripheral wall of the centering hole 121 formed in the optical box 120. Since the load is received by the protrusion 117, the shaft 111 is not directly affected. As a result, it is possible to prevent the perpendicularity between the mounting plate 108 and the shaft 111 from changing.

(Embodiment 3)
A third embodiment of the present invention will be described below with reference to FIGS. 3 (a), 3 (b), and 3 (c). FIG. 3A is a longitudinal sectional view of a polygon mirror scanner motor according to Embodiment 3 of the present invention. FIG. 3B is a bottom view of the polygon mirror scanner motor according to the third embodiment of the present invention. 3 (a) and 3 (b), the difference from the first embodiment shown in FIG. 1 (a) is that instead of forming the bulging portion 109 from the mounting plate 108, three circles are formed. The arc-shaped wall portion 118 is cut and raised. This wall portion 118 is a cylinder that circumscribes the three wall portions 118 around the connecting portion 116 (fixing portion) for fixing the shaft 111 of the mounting plate 108 on the side opposite to the side where the stator core 112 is disposed. The envelope surface of the shape is formed so as to be concentric with the shaft 111.

  FIG. 3C is a longitudinal sectional view showing a state in which the polygon mirror scanner motor according to the third embodiment is attached to the optical box 120 of the LBP.

  As shown in FIG. 3C, the LBP optical box 120 has an outer diameter dimension of a cylindrical envelope surface circumscribing three wall portions 118 formed by protruding from the mounting plate 108 of the polygon mirror scanner motor. A centering hole 121 having a slightly larger diameter is formed. Since the cylindrical envelope surface circumscribing the three wall portions 118 of the polygon mirror scanner motor is formed so as to be concentric with the shaft 111, the three wall portions 118 are aligned with the center of the optical box 120. By inserting into the hole portion 121, the shaft 111 of the polygon mirror scanner motor and the optical box 120 can be centered and positioned.

  With this configuration, as in the first embodiment, when the polygon mirror scanner motor is fixed to the optical box 120, it is applied laterally via the inner peripheral wall of the centering hole 121 formed in the optical box 120. Since the load is received by the wall portion 118, the shaft 111 is not directly affected.

  As a result, it is possible to prevent the perpendicularity between the mounting plate 108 and the shaft 111 from changing.

  In the second embodiment and the third embodiment, three projections 117 or three wall portions 118 are formed. However, the cylindrical envelope surface circumscribing the plurality of projections or wall portions is formed with the shaft 111. If it forms so that it may become concentric, it will not be limited to this, If the number is two or more, the same effect will be acquired.

(Embodiment 4)
The fourth embodiment of the present invention will be described below with reference to FIGS. 4 (a), 4 (b) and 4 (c). FIG. 4A is a longitudinal sectional view of a polygon mirror scanner motor according to Embodiment 4 of the present invention. FIG. 4B is a bottom view of the polygon mirror scanner motor according to the fourth embodiment of the present invention. 4 (a) and 4 (b), the difference from the first embodiment shown in FIG. 1 (a) is that the bulging portion 109 from the mounting plate 108 is opposite to the side where the stator core 112 is disposed. Instead of projecting to the side, the bulging portion 119 is formed to project to the side where the stator core 112 is disposed. The bulging portion 119 is formed around the connecting portion 116 (fixing portion) for fixing the shaft 111 of the mounting plate 108 so that the envelope surface is concentric with the shaft 111.

  FIG. 4C is a longitudinal sectional view showing a state in which the polygon mirror scanner motor according to the second embodiment is attached to the optical box 120 of the LBP.

  As shown in FIG. 4C, the present embodiment is a centering hole formed in the LBP optical box 120 in the first to third embodiments for centering the polygon mirror scanner motor. This is applied when a centering protrusion 122 is formed instead of 121. The diameter of the centering protrusion 122 is slightly smaller than the outer diameter of the bulging portion 119 formed by protruding from the mounting plate 108 of the polygon mirror scanner motor. Since the bulging portion 119 of the polygon mirror scanner motor is formed to have a cylindrical envelope surface concentric with the shaft 111, the bulging portion 119 of the polygon mirror scanner motor is used as the centering protrusion of the optical box 120. By inserting into the section 122, the shaft 111 of the polygon mirror scanner motor and the optical box 120 can be centered and positioned.

With this configuration, as in the first embodiment, when the polygon mirror scanner motor is fixed to the optical box 120, it is applied in the lateral direction via the outer peripheral wall of the centering protrusion 122 formed on the optical box 120. Since the load is received by the bulging portion 119, the shaft 111 is not directly affected. As a result, it is possible to prevent the perpendicularity between the mounting plate 108 and the shaft 111 from changing.

  In each of the above-described embodiments of the present invention, the circuit board 107 and the mounting plate 108 are provided so that the bulging portions 109 and 119 or the protruding portions 117 or the wall portions 118 that are positioning portions can be easily formed. Although it is configured with separate parts, if there is no problem in processing, the circuit board is configured by an iron board in which the circuit board 107 and the mounting plate 108 are integrated as in the conventional technique, and the positioning portion is directly attached to the circuit board. Even if formed, the same effect can be obtained.

  Further, although the positioning portion is formed integrally with the mounting plate 108, for example, a similar effect can be obtained by attaching another cylindrical member to the mounting plate 108 concentrically with a gap from the outer periphery of the shaft 111. In this case, although the number of parts increases, since it is not necessary to form a positioning portion on the mounting plate 108, it is easy to maintain the squareness of the mounting plate 108 and the shaft 111 with high accuracy.

  The motor mounting positioning structure according to the present invention is a motor having a shaft that is directly fixed to a mounting plate that is a mounting portion to the device, while ensuring the accuracy of the perpendicularity between the shaft and the mounting plate. It is related to a positioning structure that can attach the concentricity of the shaft of the motor and the motor with high accuracy, and is particularly useful as a structure related to fixing with high mounting accuracy.

(A) is a longitudinal sectional view of the polygon mirror scanner motor according to the first embodiment of the present invention, (b) a bottom view of the polygon mirror scanner motor according to the first embodiment of the present invention, and (c) is a polygon according to the first embodiment. A longitudinal sectional view of the mirror scanner motor attached to the LBP optical box 120 (A) is a longitudinal sectional view of a polygon mirror scanner motor according to the second embodiment of the present invention, (b) a bottom view of the polygon mirror scanner motor according to the second embodiment of the present invention, and (c) is a polygon according to the second embodiment. A longitudinal sectional view of the mirror scanner motor attached to the LBP optical box 120 (A) is a longitudinal sectional view of a polygon mirror scanner motor according to Embodiment 3 of the present invention, (b) is a bottom view of the polygon mirror scanner motor according to Embodiment 3 of the present invention, and (c) is a polygon according to Embodiment 3. A longitudinal sectional view of the mirror scanner motor attached to the LBP optical box 120 (A) is a longitudinal sectional view of a polygon mirror scanner motor according to Embodiment 4 of the present invention, (b) is a bottom view of the polygon mirror scanner motor according to Embodiment 4 of the present invention, and (c) is a polygon according to Embodiment 4. A longitudinal sectional view of the mirror scanner motor attached to the LBP optical box 120 Sectional view of a conventional polygon mirror scanner motor described in Patent Document 1 (A) is sectional drawing before inserting the shaft of the conventional polygon mirror scanner motor described in patent document 1 in a circuit board, (b) Circuits the shaft of the conventional polygon mirror scanner motor described in patent document 1 Sectional drawing of the state fixed to the board | substrate, (c) Top view of the state which fixed the shaft of the conventional polygon mirror scanner motor described in patent document 1 to the circuit board (A) is a longitudinal sectional view of the conventional polygon mirror scanner motor described in Patent Document 1 with the LBP optical box 301 attached thereto, and (b) is a conventional polygon mirror scanner motor described in Patent Document 1. Is a longitudinal cross-sectional view for explaining a problem in a state in which is attached to the optical box 301 of the LBP

Explanation of symbols

100, 200 Rotor part 101, 201 Rotor frame 102, 202 Rotor boss 103, 203 Polygon mirror 104, 204 Rotor mabnet 105, 205 Cylindrical part 106, 206 Herringbone groove 107, 211 Circuit board 108 Mounting plate 109, 119 Swelling part 110, 210 Stator assembly 111, 220 Shaft 112, 212 Stator core 113, 213 Stator coil 114, 214 Winding assembly 115, 216 Through hole 116, 217 Connection portion 117 Projection portion 118 Wall portion 120, 301 Optical box 121, 302 Centering Hole 122 Centering protrusion 215 Drive IC
218, 219 Irradiation point 221 Shaft end

Claims (6)

A rotor frame, a rotor magnet fixed to the inner periphery of the rotor frame, a rotor boss having a cylindrical portion fixed to the center of the rotor frame, a polygon mirror inserted into the outer periphery of the cylindrical portion of the rotor boss and placed on the rotor frame; A winding assembly comprising a stator core, which is disposed opposite to the rotor magnet and laminated with a magnetic material, and a stator coil wound around the stator core, a circuit board, and a motor that holds the circuit board and holds the motor. And a stator part having a mounting plate having a mounting part to the device to be mounted, and the shaft is directly fixed to the center of the mounting plate, and either in the radial direction of the shaft or the cylindrical part of the rotor boss. A dynamic pressure bearing is formed by forming a dynamic pressure groove for generating dynamic pressure, and the cylindrical portion of the rotor boss is connected to the shim. In a polygon mirror scanner motor that is pivotally supported by a shaft, a positioning portion that is formed concentrically with an outer periphery of the shaft and a gap therebetween and is fitted to a motor mounting centering portion of a device on which the polygon mirror scanner motor is mounted. A polygon mirror scanner motor provided on the mounting plate. The polygon mirror scanner motor according to claim 1, wherein the positioning portion is a protrusion having a cylindrical envelope surface concentric with the shaft. The positioning portion is a bottomed cylindrical bulging portion formed by protruding a periphery of a fixing portion for fixing the shaft of the mounting plate to a side opposite to a side where the stator core is disposed from the mounting plate. The polygon mirror scanner motor according to 2. The positioning portion is a plurality of protrusions formed by protruding from the mounting plate to a side opposite to a side where the stator core is disposed around a fixed portion that fixes the shaft of the mounting plate. Polygon mirror scanner motor. The positioning portion is a plurality of arc-shaped wall portions formed by cutting and raising the mounting plate from a side opposite to a side where the stator core is disposed around a fixing portion for fixing the shaft of the mounting plate. The polygon mirror scanner motor according to 2. A bottomed cylindrical bulge having an envelope surface concentric with the shaft formed by a positioning portion protruding from the mounting plate to the side where the stator core is disposed around a fixing portion for fixing the shaft of the mounting plate. The polygon mirror scanner motor according to claim 1, which is a protruding portion.

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