JPS5917020A - Rotary body supporter - Google Patents

Abstract

PURPOSE:To accurately obtain coaxialness, by constructing a rotary assembly unit to be rotated with a fixed shaft, equipped with herringbone and spiral grooves on the surface, as the center. CONSTITUTION:A hollowed cylinder 38 having an internal peripheral size, in which a prescribed clearance is formed between the peripheral part of a fixed shaft 33 and said cylinder, is externally fitted rotatably to the fixed shaft 33 equipped with a herringbone groove 36 and a spiral groove 37. By this constitution, coaxialness is accurately obtained because of one bearing as compared with the constitution in which a motor shaft is conventionally mounting 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 mirror light deflector,
This invention relates to a rotating body support for supporting a rotating body such as a polyhedral mirror.

[Technical background of the invention and its problems]

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

In recent years, laser printers capable of high-speed printing of 10,000 lines per minute or more have been developed, and have achieved considerable success. As shown in Fig. 1, this laser printer deflects a laser beam (laser beam) emitted from a laser beam 1 through a 2* rotating multi-faceted experimental beam deflector 3, and combines the deflected laser beam 2. Image lens unit (
FQ lens) 4 Photoreceptor 5 uniformly charged in advance
An electrostatic latent image is formed on the photoreceptor 5 by scanning upward.

Further, the rotating polygonal light deflector 3 is composed of a multifaceted experience 6 and a motor 7 for rotating the multifaceted experience 6 at high speed, and has a configuration as shown in FIG.

That is, the polyhedral body 6 is a mirror that is fitted onto the tapered upper end portion 8a of the motor shaft 8 of the motor 7 and pressed by a nut 10 screwed onto the threaded portion 8b of the upper end of the motor shaft 8. It is held in place by a presser body 11. In addition, in the axial direction of the motor shaft 8, several motor rotors 12 are provided at the central portion thereof, and a motor housing 1s (a stator 14 is attached to the illumination) surrounds the motor rotors 12. , a shaft drive unit 1 that drives a motor shaft 8
5.

Additionally, ring zone 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 8 has a dogleg-shaped Heringane group 17...a group forming part 8er8c that is completely released on its circumferential surface, and a few microns on the mutually opposing surfaces of these group forming parts 8c+8cf. A cylindrical bearing member 18.18 is attached to the motor housing 13 so as to surround the motor housing 13 with a very small gap.

In addition, several inner magnet rings 19 are fitted to the lower end of the motor shaft 8.
It is attached to the lower end surface of the motor housing 13 through a bolt 2θ (a
Several outer (i11) magnet rings 22... are provided to surround the magnet rings 9... with a gap of several hundred microns in their mutually opposing m1 parts.The inner magnet rings 19...・Outside 1111 Magnet ring 22
...It is magnetized so that it melts and has an attractive force. and,
These attraction forces increase the axial force on the motor shaft 8 (
The magnetic thrust bearing 231C mainly receives the motor shaft 8 and supports the motor shaft 8 in a suspended state.

Further, the outer magnet ring 22... is held by a ring holder 24, and this ring holder 241d is located at one position of the motor housing 13 holder T! tl
(It is slidably fitted to 25.

The motor housing 13 includes a housing body 13a having a stepped hole, an end plate (motor end plate) 13b that closes a lower opening of the housing body 13i, and a motor end plate that closes an upper opening of the housing body 13h. It consists of a cap 13e.

In the above configuration, when the motor shaft 8 starts to rotate, the air flows between the bearing members 18, 111 and the bearing members 18, 111 by 3 μm due to the effects of the Herringane groups 17, 16, 16, and 16. By flowing into the 6 μm gap, the pressure distribution inside the gap becomes high at the center of the bearing, and this pressure causes a force in the radial direction to be applied.

On the other hand, the motor shaft 8 is in a state where the suction force and thrust load of the inner magnet ring 19 attached to the lower end of the motor shaft 8 and the outer magnet ring 22 attached to the motor housing 13 are balanced. Maintained. Therefore, the motor shaft 8 is in a non-contact state and the motor shaft 8 is in a non-contact state.
It can continue to rotate at a high speed of 0 rpm to 15000 rpm.

Therefore, n is attached to the upper end of the motor shaft 8 +n++.
The multifaceted experience 6 is rotated at high speed, and the laser beam 2 is directed horizontally at high speed.

However, in the above conventional configuration, Nj1 like
There is a problem.

That is, polyhedral steel6. Since the motor shaft 8 on which the motor rotor 12 and the like are assembled and fixed is supported by two hydrodynamic air journal bearings 16 and 16, one of the hydrodynamic air journals 16 and 16 must be made detachable.

Therefore, in the conventional example, the hydrodynamic air journal bearing 16
The bearing member 18 is press-fitted into the motor cap 13c, and this motor character 7' l 3 e is attached and detached from the housing body 13a, and the multifaceted experience 6 and the motor rotor 1 are completed.
2 is assembled and fixed to the housing 13 of the motor shaft 8.
Assembly against.

I am going to do a complete disassembly.

However, in a structure in which one hydrodynamic air journal bearing J6 is detachable, when assembled, this 1L 11 pressure air journal bearing 16 and the other hydrodynamic air journal bearing 16
It is very difficult to assemble the motor shaft 8 with a high degree of coaxiality within about 5 μm, and the motor shaft 8 may not be able to rotate smoothly. For this reason, in the past, in order to improve the coaxiality of the circumferential dynamic pressure air journal bearing 16.16, hot wire workers required long hours to perform assembly, adjustment, etc., reducing productivity and maintainability. In addition, there was a problem of increasing production costs and running costs.

[Purpose of the invention]

The present invention has been 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 that it can rotate at high speed, and to facilitate processing, assembly, adjustment, etc., thereby increasing productivity. 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-mentioned object, the present invention has a fixed shaft having a herring peen groove and a spiral groove on its surface, a rotating member having a rotating body attached thereto, and a fixed axis of the rotating member. The rotating member can be brought into a non-contact state with respect to the fixed shaft by fluid dynamic pressure generated in the herring pawn groove and the spiral groove when rotating around the fixed shaft.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to FIG. 3 and FIG. 4M. FIG. 3 shows a rotating polyhedral flfi deflector to which the rotating body support device of the present invention is applied.

This rotary polyhedral blunt light deflector 30C' consists of a drive mechanism section 32 that rotates the polyhedral body 3 and the polyhedral body 31 at high speed in a predetermined direction (in the embodiment, clockwise when viewed from above). The structure is as follows. In the figure, 33 is a fixed shaft, and the lower end mounting portion 33h of this fixed shaft 33 is attached to the motor housing 3.
It is press-fitted and fixed into the mounting hole 35 of No. 4 by means such as cross-fitting.

Herring pawn grooves 36.36 are formed on both upper and lower ends of the circumferential surface of the non-press-fitted portion of the identification shaft 33, and a S-gilar groove 37 is formed between the herring g-on 7p 36.36. has been done. The above ring groove 36, 3
6h The arrow-shaped tip faces the direction of rotation of the polyhedral casting 31, and the spiral groove 37 is also formed so as to wrap around and rise in the direction of rotation of the polyhedral casting 31.

Also, like this, the Herring groove 36. ．． 16 and a spiral groove 37, a hollow cylindrical cylinder 38 with an inner diameter of 1 and a gap between the fixed shaft 33 and the outer diameter part of 3 μ7n to 6 μη; Press-fitted into the inner diameter part of the upper end of the thrust receiving part 39
A rotary part 4 consisting of a cap 40 and a cap 40 constituting the rotary part 4 are rotatably fitted on the outside. The cap 40 is made of a low-friction synthetic resin with a lubricating surface such as Delrin, and minimizes contact friction with the upper end surface of the fixed shaft 33 that comes down immediately after the rotation of the rotating member 4 starts and immediately before it stops rotating. With spiral groove 3
In order to maintain the fluid dynamic pressure generated by 2 at a constant value, a small hole 42 with a diameter of about 0.2 mm is provided.

Further, the cylinder 38 of the rotating part 41 has a motor rotor 4.
Three trigrams and a polyhedral body 3) as a rotating body are installed as described below. That is, the motor rotor 43 has a flange protruding from the center of the cylinder 38 in the vertical direction.
It is press-fitted and fixed in such a way that the inner peripheral edge of the upper end of the opening is in contact with the lower surface A of 8a.
The mirror adapter 44 is fitted onto the outside so that the lower edge of the opening is in contact with the upper surface fI11 of the flange 38a, and when the polyhedral armor 31 comes of age, the mirror adapter 44 is fitted into the upper end side of the cylinder 38 and is pressed by a nut 45. It is clamped and fixed by a sharp presser body 46. On the other hand, the motor housing 34 is in a state surrounding the motor rotor 43.
*/+Coil 4yf: The heated motor stator 48 is attached, and the rotating part 41. Motor rotor 4g,
Rotating assembly 49f consisting of polyhedral needle 31, etc.: Drive Note that a cover 50 is superimposed on the motor housing 34, and these surround the polyhedral body 31 and the drive mechanism section 32 that drives the polyhedral body 3). A closed container 51 is configured. Moreover, clean air is sealed inside this airtight container 51.

In addition, FIG. 4 shows the axial distribution of the radial pressure of the fixed shaft 33, where point a is the lower end portion of the fixed shaft 33, and point b is the lower ballin bean groove 36 and the radial groove. 3
7, the 0 point corresponds to the center of gravity 52 of the rotating assembly 49, and the 6 point is the upper hering gain f! The boundary portion of the Js6 tosno-4-iral groove 37 and point e indicate the upper end portion of the fixed shaft 33, respectively.

By energizing the drive coil 47, a circuit magnetic field is generated in the motor stator 48, and the rotating assembly 49 consisting of the rotating member 41, the motor rotor 43 attached thereto, the multi-faceted experience 31, etc. is moved in a predetermined direction (this implementation In the example, the drive is clockwise (when viewed from above). This rotating assembly 49
When the bellin/''!-7B 36 and 36 rotate, air flows into the gap between the rotating shaft 33 and the cylinder 38 of the rotating member 4, generating air pressure in the radial direction as shown in FIG. An air dynamic pressure journal bearing is formed in the area.

On the other hand, an upward air flow is generated by the action of the spiral groove 37, and compressed air is sent into the lower surface eye 11 of the cap 4o as the thrust receiving portion 39 of the rotating member 41, and the compressed air is fed into the upper end surface of the fixed shaft 33. A compressed air layer 53 is formed between the lower surface of the cap 400 and the lower surface of the cap 400 . Thus, a rotating assembly 49 consisting of the rotating member 4, the motor rotor 43, the polyhedral cape 31, etc.
can be supported in a non-contact manner with respect to the fixed l11]33.

At this time, since the herring peen groove 36 is not provided at a position lower than the center of gravity 52 of the rotating assembly 49, unstable rotational movement occurs when the herring zone m36 is formed only at a position higher than the center of gravity 52. It can be completely prevented.

That is, when only the upper Hering zone groove 36 is provided, the radial air pressure generated by the Herring bean groove 36 and the spiral groove 37 is applied to the rotating assembly 4.
The compressed air layer 5 is located at the upper end of the fixed shaft 33 from the center of gravity 52 of the fixed shaft 33.
3, it is as if the rotating assembly 49 is supported at a position higher than the center of gravity 52 of the rotating assembly 49. Therefore, during high-speed rotation, the action of the gyroscopic moment of the rotating assembly 49 and the gravity at the center of gravity 52 generates a force that causes the lower end of the rotating assembly 49 to rise upward, and furthermore, as it moves toward the lower end of the rotating assembly 49, the force increases in the radial direction. Since the q atmospheric pressure becomes small, the rotating assembly 49 will perform an extremely unstable swing rotation υ. In other words, this allows for a multifaceted experience 31 of a rotating body.
There is a serious opening angle in which the surface deflection n is large and the vertical deflection of the laser beam adversely affects the printing operation.

However, in the case of this embodiment, since the Heringdain groove 36 is also provided near the lower end of the rotating assembly 49, the above-mentioned six forces and gyroscopic moments applied to the center of gravity 52 of the rotating assembly 49 during high-speed rotation are The rising force of the rotating assembly 49 caused by the action of the rotating assembly 49 can be suppressed by the pressure between the shafts a and b below the center of gravity 52 shown in FIG. 4, and stable high-speed rotation can be achieved.

Additionally, since the rotational speed of the rotational assembly 49 is below the rated speed immediately after the rotation of the rotational assembly 1*49 starts and immediately before the same rotation 1 stops, there is no need to float the rotational assembly 49 on the upper end surface side of the fixed shaft 33. The compressed air layer 53 cannot be formed, and the cap 4
0 and the fixed shaft 33 are in direct contact with each other, but the character 7"417
Since the cap is made of a low-friction synthetic resin or the like that nails the lubricated surface, there is no loss of rotation, no rotation failure due to generation of shavings due to abnormal wear, and no pinching of the small hole 42 of the cap 40.

In addition, the compressed air between the upper end surface of the fixed shaft 33 and the lower surface of the character 7° 40 caused by the action of the spiral groove 37 is appropriately released from the small hole 42 formed in the cap 40, and the rotation is constant under the rated rotation. A compressed air layer 53 having a thickness of . In addition, in order to generate compressed air with sufficient pressure to levitate the entire rotating assembly 49, the rotational speed of the rotating assembly 49 must be changed to The winding angle of the circular groove 37 is set in advance.

As a result, the polyhedral body 31 is rotated at high speed and deflects the laser light guided into the cover 50 through an entrance portion (not shown) formed in the cover 50 (a hole sealed by a transparent body). There is. Note that the deflected laser beam is led out to the photoreceptor side, etc., through a light output portion (not shown) formed in the cover 50 (a hole sealed by the imaging lens unit).

In the above embodiment, the herringbone groove 36 is also formed at the upper end of the fixed shaft 33 to generate pressure in the radial direction, equalize the pressure around the shaft, and suppress the vibration of the rotating assembly 49. Although this is effective, it is not necessarily necessary because the pressure in the radial direction caused by the ring groove 36 at the upper end of the fixed shaft 33 is also generated by the spiral groove 37. Therefore, as shown in FIG. 5, a herring bean groove 36 is provided at the lower side of the rotary assembly 49 like the fixed part 33, and a radial groove 37 is provided above it, as shown in FIG. 6. It is also possible to obtain the same axial distribution of the radial pressure of the fixed shaft 33 as shown in the above-mentioned fourth part 21, and obtain exactly the same effect.

Furthermore, the rotating body support device W of the present invention was applied to the rotating polyhedral original deflector 30 to support the polyhedron @3.
Of course, the present invention is not limited to this, and may be applied to rotating bodies other than the multifaceted experience 3.

It goes without saying that the present invention can be modified in other ways without departing from the gist of the invention.

In addition, in the description of the other embodiments (FIGS. 5 and 61), the same parts as those of the above-mentioned embodiment are given the same reference numerals, and the explanation thereof will be omitted.

〔Effect of the invention〕

As explained above, the present invention has a rotating member having a rotating body attached to a fixed shaft having a herring bean groove and a spiral groove on its surface fitted on the outside, and when the rotating part H rotates about the fixed shaft. Fluid dynamic pressure generated in the herring peen groove and the spiral groove causes the rotary part to be in a non-contact state with the fixed shaft. Therefore, compared to the conventional system in which the motor shaft to which the rotating body and motor rotor are attached is supported by two hydrodynamic air journal bearings, since there is only one bearing, coaxiality can be manufactured with extremely high precision. For example, it can reliably support rotating objects such as polyhedral sharps so that they can rotate at high speed, and it is also easy to process, assemble, and adjust, greatly improving productivity and maintainability, and reducing production costs and running costs. It produces such effects.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the scanning part of a Rayleigh beam printer using a rotating polygonal optical deflector, Fig. 21 is a longitudinal cross-sectional side view of a conventional rotating polygonal St deflector, and Fig. 3 is a rotating body support of the present invention. FIG. 4 is an explanatory diagram showing the axial distribution of the radial pressure on the fixed shaft of FIG. 3, and FIG. FIG. 6 is a longitudinal cross-sectional view of a rotary polyhedral button light deflector adopted in another embodiment of the rotating body support device d. FIG. 6 is an explanatory diagram showing the axial distribution of the radial pressure of the fixed shaft in FIG. 3...Rotating body (multi-sided closed furnace), 33...Fixed axis, 36
...Herringbean M, 37...su/? (Tsuru groove, 3
8...Cylinder, 39...Thrust receiver, 40...
・Ki, Y up, 4)...1 (7) Current phase, 42...Small hole, 43...Motor rotor, 49...Rotating assembly. 3rd cause Figure 4 Figure 5 Figure 6, □58Ha4・-J Mr. Kazuo Wakasugi, Commissioner of the Japan Patent Office■, Indication of the case Patent application No. 126124/1982 2, Name of the invention Rotating body support device 3 , Relationship with the case of the person making the amendment Patent applicant (307) Tokyo Shibaura Electric Co., Ltd. 4, Agent address 17 Mori Pill, 1-26-5 Toranomon, Minato-ku, Tokyo 105 Phone: 03 (502) 3181 (
Main representative) 6. Correction details 7, Correction details, page 3, line 8 r (FQ lens)"
(Fθ lens)”.

Claims (5)

[Claims] (1) It is equipped with a fixed shaft having a herring peen groove and a spiral groove on its surface, and a rotating member that is fitted onto the fixed shaft and has a rotary body attached thereto and is rotated about the entire center of the rotating shaft. , characterized in that the rotating member can be brought into a non-contact state with respect to the fixed shaft by fluid dynamic pressure generated in the Hering zone groove and the spiral groove as the rotating member rotates. Rotating body support device. (2) At least one set of herringbone grooves is provided on the surface of the fixed shaft with low centering of the rotating assembly consisting of one rotating body, etc., and a spiral groove is provided above the herringbone groove. The rotating body support device according to claim 1, characterized in that the dj5 has the following configuration: (3) At least one or more sets of herring zone grooves are provided at each end of the fixed shaft, and these herring zone grooves H? 2. The rotating body support device according to claim 1, wherein a spiral groove is provided at an intermediate position between the grooves. (4) The rotary member support according to claim 1, characterized in that the rotary member is provided with a thrust receiver having all small holes for maintaining the fluid dynamic pressure generated by the spiral groove at a constant value. Device. (5) At least the part of the thrust bearing facing the fixed shaft end face is
The rotating body support device according to claim 4, characterized in that it is formed from a material having an open groove surface.