JPS5917023A - Rotary body supporter - Google Patents

Abstract

PURPOSE:To accurately obtain coaxialness, by construction such that a rotary assembly unit is rotated with a fixed shaft as the center while being supported by a thrust supporting magnetic bearing. CONSTITUTION:A hollowed cylinder 37 having an internal peripheral size, in which a prescribed clearance is formed between the peripheral part of a fixed shaft and said cylinder, is externally fitted rotatably to the fixed shaft 33. An inner magnetic ring 40 of a thrust supporting magnetic bearing 39 is mounted to said cylinder 37. While an outer magnetic ring 48 is mounted to a housing 34. By such constitution, coaxialness is accurately obtained because of one bearing as compared with the constitution in which a motor shaft as conventionally mounted with a rotary body and a motor rotor is supported by two bearing parts.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention is applied to, for example, a rotating polyhedral furnace optical deflector,
This invention relates to rotating body support equipment for supporting rotating bodies such as multi-faceted experiences.

[Technical background of the invention and its problems]

In recent years, the amount of information waste has increased significantly, and accordingly printers that record information are required to be faster each year.

In recent years, high-speed printing of more than 10,000 lines per minute has become more common.
A curling laser printer has been developed and has achieved considerable success. As shown in FIG. 1, this laser printer emits light from a laser light source 1. A laser beam (laser beam) 2 is deflected through a rotating polyhedral light deflector 3,
This deflected laser beam 2 is converted into an imaging lens unit) (FQ
The photoreceptor 5 is scanned through a lens 4 onto a photoreceptor 5 that has been uniformly charged in advance, and an electrostatic latent image is formed on the photoreceptor 5.

Further, the rotating polyhedral end light deflector 3 is composed of a polyhedron @6 and a motor 7 for rotating the polyhedral experience 6 at high speed, and has a configuration as shown in FIG. 2.

That is, the above-mentioned multifaceted experience 6 consists of the mirror adapter 9 fitted to the upper end chi 1 8a of the motor shaft 8 of the motor 7 and the nut 1 screwed together to the upper end threaded part 8bK of the motor shaft 8.
It is held in place by the mirror holding body 1 which is pressed by the mirror holder 1. A motor rotor 12 is attached to the axially central portion of the motor shaft 8, and a stator 14 is attached to the motor housing 13 to surround the motor rotor 12. It constitutes a shaft drive section 15 that drives the.

Additionally, herringbone-type dynamic pressure air journal bearings 16.16 are provided in both the upper and lower directions of the shaft drive section 15, and support the motor shaft 8 in the radial direction.

That is, the motor shaft 8Vc has a group forming portion Bcrge formed with dogleg-shaped Hering zone groups 17 on its circumferential surface, and these group forming portions 8c and 11c are formed on their mutually opposing surfaces. A cylindrical bearing member 18.18 is attached to the motor housing 13 so as to surround the motor housing 13 with a minute gap of several microns between the two.

Several inner magnet rings 19 are still fitted to the lower end of the motor shaft 8.
The motor housing 1 is held by a ring retainer 2 attached to the lower end of the motor housing 1 via a bolt 20.
On the 3 side, several outer magnet rings 22 are provided so as to surround these inner magnet rings 19 with a gap of about several hundred microns between their mutually opposing surfaces. The inner magnet rings 19... and the outer magnet rings 22... are magnetized to exert an attractive force. These attraction forces constitute a magnetic thrust bearing 23 that receives the axial force (mainly its own weight) of the motor shaft 8 and supports the motor shaft 8 in a suspended V-shaped state.

The outer magnet ring 22... is still held by the ring holder 24, and this ring holder 2
4 is slidably fitted into the holder fitting portion 25 of the motor housing 13.

The motor housing 13 includes a housing body 13a having a stepped hole, and an end plate (motor end plate) 73b that closes the lower end opening of the housing body 13g.
and a motor cap 13c that closes the upper end opening of the housing body 3a.

In the above configuration, when the motor shaft starts to rotate 80 times, the herringbone type hydrodynamic air journal bearing 16.16 receives air from the bearing member 18.18 by 3μtrL due to the effect of the herringbone group 17... 6μm
By flowing into the gap υ, the pressure distribution inside the gap becomes thicker in the center of the bearing, and this pressure causes the pressure distribution in the radial direction (
radial direction).

On the other hand, the motor shaft 8 has an inner magnet ring 19 attached to its lower end, and an outer magnet ring 22 attached to the motor shaft 13. It has been maintained in a good condition.

Therefore, the motor shaft 8 is in a non-contact state 4
It can continue to rotate at a high speed of 000 rpm to 15000 rpm.

As a result, the multifaceted lens 6 attached to the upper end of the motor shaft 8 is rotated at high speed, and the laser beam 2 is deflected at high speed.

However, the conventional configuration described above has the following problems.

That is, in order to support the motor shaft 8 on which the motor rotor 12, etc. are assembled and fixed, by the two hydrodynamic air journal bearings 16, 16, one of the hydrodynamic air journal bearings 16 is made removable. I have to keep it.

For this reason, in the conventional example, the hydrodynamic air gloss bearing 16
The bearing member 18 is press-fitted into the motor cap 1.9c, and this motor character 7''13c is attached and detached from the Haunong main body 13m.
The motor shaft 8, on which the motor shaft 8 is assembled and fixed, is assembled and disassembled from the housing 13.

However, in a structure in which one hydrodynamic air journal bearing 16 is detachable, the coaxiality between this hydrodynamic air journal bearing 16 and the other hydrodynamic air journal bearing 16 must be within about 5 μm during assembly. It is very difficult to assemble the screen with high precision, and the motor shaft may not rotate 80 times smoothly. To avoid this, in the past, in order to increase the coaxiality of both hydrodynamic air journal bearings 16 and 16, skilled workers required long hours to process, assemble, adjust, etc., reducing productivity and maintainability. This is not stupid, but it has the problem of increasing production costs and running costs.

[Purpose of the invention]

The present invention was made based on the above circumstances, and its purpose is to be able to reliably support a rotating body such as a multi-faceted experience so as to be able to rotate at high speed, and to improve productivity by facilitating processing, assembly, adjustment, etc. The present invention aims to provide a rotating body support device that can greatly improve maintainability and reduce production costs and running costs.

[Summary of the invention]

In order to achieve the above object, the present invention has a fixed shaft fitted with a cylinder to which a motor rotor and a rotating body are attached, and a rotating assembly including the cylinder, motor rotor, rotating body, etc. It is designed to rotate around a fixed shaft while being supported by bearings.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 3 and 4. FIG. 3 shows a rotating multifaceted experimental light deflector to which the rotating body support device of the present invention is applied.

This rotating multi-faceted experience light deflector 30 consists of a multi-faceted experience 3 and a drive mechanism section 32 that rotates the multi-faceted experience 31 at high speed in a predetermined direction (clockwise when viewed from above in the embodiment), and has the following configuration. It has become.

In the figure, 33 is a fixed shaft, the lower end attachment part of this fixed shaft 33, 3
3a is press-fitted and fixed into the mounting hole 35 of the motor housing 34 by means such as shrink fitting, as shown in FIG.

Herringbone grooves 36 and 36 are formed on both upper and lower ends of the circumferential surface of the non-press-fitted portion of the fixed shaft 33. These herringbone grooves 36, 36 are formed in a shape with an arrow-shaped tip facing the direction of rotation of the multifaceted experience 31.

A hollow cylindrical cylinder 37 having an inner diameter that forms a gap of 3 μm to 6 μm between the fixed shaft 33 and the outer diameter portion of the fixed shaft 33 is rotatably fitted on the fixed shaft 33. A polyhedral hood 3 serving as a rotating body of a motor rotor 381 and an inner magnetic ring 40 of a magnetic bearing 39 for thrust support are attached to this cylinder 37 as will be described later. That is, the motor rotor 38 has a flange 37 a that projects slightly upward from the vertical center of the cylinder 37 .
The inner peripheral edge of the upper end of the opening is press-fitted into contact with the lower surface of the opening.

Still, multi-faceted experience 31 is the above-mentioned Tsuba? 7g so that the lower end peripheral edge of the opening is in contact with the upper surface side of the opening 7g, and is pressed and fixed via an elastic sheet 43 and a retainer 42 which is fitted onto the upper side and pressed by a nut 41. Further, the inner magnetic ring 40 is inserted into the small diameter portion of the lower end of the cylinder 37 and is held between the step portion of the cylinder 37 and a retaining ring 44 which is screwed to the lower end of the cylinder 37.
1 is fixed.

On the other hand, a motor stator 46 with a drive coil 45 is attached to the motor housing 34 so as to surround the motor rotor 38, and is composed of a cylinder 37, a motor rotor 38, a polyhedron @31, an inner magnetic ring 40, etc. The rotary assembly 42 is driven once.

Finally, an outer magnetic ring 48 is provided surrounding the inner magnetic ring 4o, and a thrust supporting magnetic bearing 39 supports the rotating assembly 47 in the thrust direction.
It consists of

The outer magnetic ring 48 is fitted into a stepped recess 49 formed in the motor housing 34 and is pressed and fixed by a part of the motor stator 46 fixed to the motor housing 34 .

An annular motor drive circuit board 50 that is electrically connected to the drive coil 45 is still attached to the motor stator 46 . The hole 50a of the motor drive circuit board 50 has a larger diameter than the outer diameter of the inner magnetic ring 40, so that the inner magnetic ring 40 can be inserted into and removed from the hole 50a with the inner magnetic ring 40 fixed to the cylinder 37. It has become.

Further, the motor housing 34 and the cover 51 superimposed on the motor housing 34 constitute an airtight container 52 that surrounds the multi-face experience 31 and the drive mechanism section 32 that drives the multi-face experience 31. Moreover, clean air is sealed inside this airtight container 52.

Note that the cover 51 is configured such that the inner diameter portion of the open end is fitted into the motor stator 46 which is press-fitted and fixed to the motor housing 34, and the fixing of the cover 51 to the motor housing 34 is performed in one step.
This can be done using a book fixing screw 53.

Nao, upper and lower herringbone grooves 3L of fixed shaft 33;
The shaft diameter between the herringbone grooves 36 and 35 is smaller than the shaft diameter of the herringbone groove 36. Since the cylinder 37 is made of the same material and has an inner diameter at both ends, extremely excellent concentricity can be achieved.For this reason, manufacturing and assembly can be performed extremely easily and with high precision.

Additionally, a motor drive circuit board 50 is attached to the motor stator 46.
Since this has been identified, the dead space inside the sealed container M52 can be effectively used and the device can be made more compact.

'On the other hand, since the outer magnetic ring 48 of the magnetic bearing 37 for thrust support is fixed to the motor housing 34 to which the fixed shaft 33 is fixed, it is fixed ifi+I+,? 3 and the outer magnetic ring 48 are obtained with high precision J& without adversely affecting the rotation of the rotating assembly 47.

By energizing the drive coil 45, a circuit magnetic field is generated in the motor stator 46, and the rotating assembly 47 consisting of the cylinder 37, motor rotor 38, inner magnetic ring 40, etc. moves in the clockwise direction. When this rotating assembly 47 rotates, air flows into the gap between the fixed shaft 33 and the cylinder 37 due to the action of the herringbone grooves 36, 36, and air pressure is generated in the radial direction, causing an air dynamic pressure journal in these parts. A bearing is formed.

On the other hand, the rotating assembly 47 is supported by a magnetic bearing 39 for thrust support.

Therefore, the rotating assembly 47 can be supported in a non-contact manner with respect to the fixed shaft 33, and stable high-speed rotation can be performed.

Thus, the polyhedron @31 is rotated at high speed and deflects the laser light guided into the cover 51 through the illustrated light entrance portion (hole sealed by a transparent body) formed in the cover 51. It has become. Note that the deflected laser light is led out to the photoreceptor side, etc., through a light exit portion (not shown) formed in the cover 51 (a hole sealed by an imaging lens unit).

In the above-mentioned embodiment I/i', the rotating body support device of the present invention is applied to the rotating polygonal optical deflector 30 to support the multifaceted experience 31, but the present invention is not limited to this. Of course, the present invention may be applied to a single rotating body other than the polyhedron 31.

In addition, it goes without saying that the present invention can be modified in various ways without departing from the gist of the present invention.

〔Effect of the invention〕

As explained above, in the present invention, a cylinder on which a motor rotor and a rotating body are attached is fitted onto a fixed shaft, and a rotating assembly consisting of the cylinder, motor rotor, rotating body, etc. is supported by a magnetic IINt+ support for thrust support. It is designed to rotate around a fixed axis.

Therefore, compared to the conventional system in which the rotating body and motor rotor are attached and the motor shaft is supported by two bearings, since there is only one bearing, coaxiality can be manufactured with extremely high precision. It is possible to reliably support rotating bodies such as those that rotate at high speed, and it is also easy to process, assemble, adjust, etc., greatly improving productivity and maintainability.
X) % It is possible to reduce running costs.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the scanning part of a laser beam printer using a rotating multi-faceted experimental light deflector, Fig. 2 is a longitudinal cross-sectional side view of a conventional rotating multi-faceted experimental light deflector, and Fig. 3 is a rotating body support of the present invention. FIG. 4 is a longitudinal cross-sectional side view of a rotating multi-facet experience optical deflector employing an embodiment of the device, and FIG. 4 is an exploded perspective view showing a main part of the embodiment with a portion cut away. 3... Rotating body (multifaceted experience), 33... Identification axis, 3
4...Motor housing, 36...Helix cane groove, 37...Cylinder, 38...Motor rotor, 3
9... Magnetic bearing for thrust support, 47... Rotating assembly. Applicant's agent Patent attorney Takehiko Suzue 13 Figure 3 0

Claims (7)

[Claims] (1) a fixed shaft, a cylinder fitted onto the fixed shaft, a motor rotor and a rotating body attached thereto, and rotated around the fixed shaft;
A rotating body support device comprising the cylinder and a thrust supporting magnetic bearing that supports the rotating assembly including the motor rotor, the rotating body, etc. in the thrust direction. (2) The journal air bearing provided on the inside of the cylinder and the thrust magnetic bearing provided on the outside of the cylinder are arranged so as to at least partially overlap in the axial direction. Rotating body support device. (3) The rotating body support device according to claim 1, wherein herringbone grooves are formed at both upper and lower ends of the fixed shaft. (4) The rotating body support device according to claim 2, wherein the shaft diameter between the upper and lower herringbone groove forming portions of the fixed shaft is smaller than the shaft diameter of the herringbone groove forming portion. (5) A rotating body according to claim 1, characterized in that a motor stator surrounding a motor rotor is fixed to a motor housing to which a fixed shaft is fixed, and a motor drive circuit board is fixed to this motor stator. Support device. (6) The rotating body support device according to claim 4, wherein the motor drive circuit board is provided with a hole having a diameter larger than the outer diameter of the inner magnetic ring of the thrust support magnetic bearing. . (7) The rotating body support device according to claim 1, wherein the outer magnetic ring of the thrust support magnetic bearing is fixed to a motor housing to which the fixed shaft is fixed.