JP2001194615A - Motor unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor unit which causes little deformation of a loading object, and causes no irregular movement of the loading object at high-speed rotation, and can suppress the imbalance. SOLUTION: The motor unit rotationally drives the loading object (for example, polygon mirror) 3 mounted on a sleeve 2 being a supporting member. The polygon mirror 3 being the loading object is fixed to the sleeve 2 being the supporting member by a mechanical fastening means, such as screw setting (by a bolt 6), a gap 14 is formed between an inner peripheral surface 3n of the loading object 3 and an outer peripheral surfaces 2g of the supporting member 2, and an adhesive 20 is charged in the gap 14. The hardening capacity for curing firmly itself as well as a high filling capacity is needed for the adhesive 20 for suppressing the motion of the loading object for example, the two- pack epoxy base adhesive, etc., is preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor unit for office machines, information equipment and audio / video equipment, and is particularly suitable for rotating a mounted object such as a mirror of a digital copying machine or a laser printer at a high speed. Motor unit.

[0002]

2. Description of the Related Art As a conventional motor unit of this type, there is, for example, a scanner unit for a digital copying machine shown in FIG. This is a support member (sleeve) 2 rotatably supported on a fixed shaft 1 via a hydrodynamic bearing.
Is equipped with a polygon mirror 3. The sleeve 2
Is rotated at a high speed by a built-in motor M, reflects laser light incident on the polygon mirror 3, and projects the light from a glass window 5 provided on the cover 4 onto an external photosensitive drum (not shown) to scan at high speed. .

The polygon mirror 3 is used after being screwed to a sleeve 2 as a support member with a plurality of bolts 6 and then corrected in balance.

[0004]

However, recently, in order to increase the copy speed of a copying machine, there is a tendency that the motor unit is required to rotate more and more at high speed. In response to this, it was found that, when trying to rotate at a high speed, a phenomenon that the vibration at the rated rotation, which was not a problem at a low speed, became large appeared.

[0005] This is a phenomenon in which when the motor is rotated at a high speed, the amount of loss of balance changes irregularly due to repeated start-stop operations. This is because the polygon mirror slightly expands due to the centrifugal force and moves irregularly in the radial direction with respect to the sleeve screwed. In order to prevent such an increase in vibration during high-speed rotation, it is necessary to prevent the polygon mirror from moving irregularly in the radial direction even when centrifugal force acts during high-speed rotation. Therefore, it is conceivable that a polygon mirror is shrink-fitted to the support member, but the mirror surface is deformed due to the influence of the interference,
Not appropriate as a measure.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a motor unit that employs a fixing method in which the mirror is less deformed and the mirror is less likely to move during high-speed rotation.

[0007]

According to a first aspect of the present invention, there is provided a motor unit for rotating a load mounted on a support member, the load being mounted on the support member. In addition to fastening by screwing or the like, a gap is provided between the inner peripheral surface of the load and the support member, and the gap is filled with an adhesive.

In the motor unit of the present invention, the adhesive filled in the gap provided between the inner peripheral surface of the load and the sleeve suppresses the irregular radial movement of the load. Therefore, even if the inner peripheral surface of the load expands due to centrifugal force, the loss of balance during high-speed rotation is suppressed, and the increase in vibration at high-speed rotation of the motor unit can be prevented.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a motor unit according to the present invention. First, the configuration will be described. A sleeve 2 as a supporting member, which is a rotating member, is supported on a shaft 1 of a fixed member which is provided upright at the center of a dish-shaped housing 10. The sleeve 2 is formed into a cup shape by fixing a disc-shaped plug 2B to the upper end of a cylindrical sleeve body 2A having a flange portion 2f protruding from the outer periphery. A hole 11 is opened.

The shaft 1 has a radial receiving surface 1r at two locations above and below the outer peripheral surface thereof at a distance in the axial direction. On the other hand, the sleeve 2 has radial bearing surfaces 2r opposed to the radial receiving surface 1r of the shaft 1 via a bearing gap at two positions above and below the inner peripheral surface. At least one of the radial receiving surface 1r and the radial bearing surface 2r (in the drawing, the radial bearing surface 2r) is provided with, for example, an asymmetric herringbone-shaped groove m for generating a dynamic pressure for feeding air toward the bearing gap. A radial fluid bearing portion R is configured.

The upper end surface of the shaft 1 is formed as a thrust receiving surface 1 s having a convex spherical shape.
Is formed as a thrust bearing surface 2s facing the thrust receiving surface 1s. And the starting torque at the time of starting is reduced by making the thrust receiving surface 1s a convex spherical surface. An object mounted on the sleeve 2 is a polygon mirror (hereinafter simply referred to as a mirror) 3. Mirror 3
Is mounted on the upper surface 12 of the flange portion 2f of the sleeve 2. However, in the case of the sleeve 2 of this example, the outer diameter of the upper portion from the position slightly raised from the upper surface 12 of the flange portion 2f is slightly shorter than that of the lower portion, and the step 13 is provided. The mirror 3 is configured such that a part of the mirror inner peripheral surface 3n is fitted to the outer peripheral surface 13g of the step 13 and the flange portion upper surface 1n.
2 and is screwed to the flange portion 2f with a bolt 6. Therefore, a gap 14 corresponding to the thickness of the step 13 is interposed between the inner peripheral surface 3n of the mirror and the upper outer diameter surface 2g of the sleeve 2. This gap 14 is for filling the adhesive, and after the mirror 3 is screwed, the adhesive 20
Is filled.

In this case, even if the inner peripheral surface 3n of the mirror 3 expands due to centrifugal force at the time of high-speed rotation, the adhesive 20 has a high filling capacity capable of filling the gap 14 and a small gap. Also, a curing ability capable of curing the mirror 3 itself and suppressing the movement of the mirror 3 is required. Specifically, a two-part epoxy adhesive is preferable. With a soft rubber-like adhesive, there is no function of suppressing the movement of the mirror 3. By providing the gap 14 for filling the adhesive, the filling of the adhesive having a high viscosity becomes easy.

In the vicinity of the outer periphery of the upper surface of the mirror 3, a step 15 for correcting the balance is provided. On the side wall of the cover 4 that covers the sleeve 2 and the mirror 3, a glass window 5 is provided at a position facing the mirror 3 in the horizontal direction, and the laser light incident on the mirror 3 is reflected and passes through the glass window 5, Irradiation is performed on an external photosensitive drum.

A rotor magnet 16 fitted to the outer peripheral surface of the sleeve 2 is mounted below the flange 2f of the sleeve 2 in the axial direction, and is fixed to the sleeve 2 by a mounting ring 17 mounted from below. On the other hand, a stator coil 18 is attached to the inner surface of the housing 1 so as to face this. The rotor magnet 16, the stator coil 18, and a control circuit board (not shown) constitute a drive motor M having a peripheral surface facing type.

The mounting ring 17 is provided with a circumferential groove 19 for correcting the balance. Next, the operation will be described. First, a method of fixing the mirror 3 mounted on the flange portion 2f of the sleeve will be described. First, a bolt 6 that has passed through a plurality of bolt holes B provided in the mirror 3 is tightened into a screw hole of the flange portion 2f. , Mirror 3 to flange 2
Screw to the upper surface 12 of f. Thereafter, the gap 20 interposed between the inner peripheral surface 3n of the mirror 3 and the outer peripheral surface 2g of the sleeve 2 is filled with the adhesive 20. In this embodiment, in order to improve the reliability of the mirror fastening, the bolt 6
A mechanical fastening means such as screwing with a screw or a disc spring (not shown) is used in combination with an adhesive. for that reason,
There is no need to require adhesive strength for the adhesive, and it is possible to select an adhesive that is hard and has a high filling function that is optimal for suppressing the movement of the mirror 3. Thus, even if a centrifugal force acts during high-speed rotation, the movement of the mirror 3 in the radial direction is suppressed.

The balance of the mirror 3 fixed and mounted in this manner is corrected while rotating the motor unit on which the mirror is mounted on a balancer. While measuring the imbalance on the balancer, the step 15
By adding a weight or a putty or the like to the peripheral groove 19 which is in contact with the outer peripheral surface of the lower part of the sleeve and bonding it, imbalance is corrected on the upper and lower surfaces of the rotating member. In the case of the present embodiment, the adhesive 20 filled in the gap 14 between the inner peripheral surface 3n of the mirror 3 and the outer peripheral surface 2g of the sleeve 2 suppresses the movement of the mirror 3 even when centrifugal force acts. Therefore, if the above-described high-speed rotation balance correction is performed once after the mirror is fixed, it is possible to prevent the balance from being lost even after repeated start-stop.

To rotate the motor unit whose balance has been corrected, the coil of the stator 18 of the drive motor M is energized via a control circuit board. When the sleeve 2 is rotated by this, gas such as air in the housing 10 is moved between the radial bearing surface 2r and the radial receiving surface 1r by the pumping action of the dynamic pressure generating groove m formed in the radial fluid bearing portion R. The sleeve 2 is fed to the radial clearance, and the sleeve 2 is supported in the radial direction by the gas pressure while maintaining the radial bearing clearance. At the same time, the gas sucked into the radial clearance of the radial fluid bearing portion R flows into the clearance (axial bearing clearance) between the thrust bearing surface 2s and the opposed thrust receiving surface 1s, and the gas pressure causes The sleeve 2 floats together with the mounting mirror 3 and rotates while being supported in the axial direction while maintaining a constant minute floating amount. The gas that has flowed into the axial bearing clearance passes through the flow hole 11 on the upper part of the sleeve 2 which is an air vent hole,
It is discharged into the motor unit internal space surrounded by the housing 10 and the cover 4.

When the sleeve 2 rotates at a high speed, the mirror 3 attached to the flange 2f of the sleeve 2 is rotated.
Also rotate at high speed. However, in the motor unit of the present invention, the mirror 3 is a mechanical fastening means (bolt 6).
And the adhesive 20 filled in the gaps 14 provided between the sleeves 2 to be fixed with a uniform force. Further, since the adhesive 20 is hard and has a high filling function, it has a large rotation. There is no problem that the rotation is unbalanced due to the influence of centrifugal force, heat generation, or the like, and the mirror surface processed with high precision is deformed.

In the above embodiment, the mounted object is described as a polygon mirror. However, the present invention is not limited to this, and can be applied to a motor unit equipped with other components. Further, the bearing interposed between the shaft and the sleeve is not limited to the fluid bearing using gas, and can be widely applied to a motor unit that drives a mounted article at a high speed by using another bearing.

Although the above embodiment has been described with respect to the motor unit having the fixed shaft rotating sleeve, the present invention is also applicable to a motor unit having the fixed shaft rotating sleeve.

[0021]

As described above, according to the motor unit according to the present invention, the load is uniformly fixed to the support member by using the mechanical fixing means such as screwing together with the adhesive, so that the high-speed rotation is achieved. The effect of suppressing the irregular movement of the load in the radial direction with respect to the support member due to the centrifugal force can be suppressed, and as a result, the deformation of the load can be reduced, and the loss of balance at high speed rotation can be suppressed. To play.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a motor unit showing one embodiment of the present invention.

FIG. 2 is a schematic sectional view of a conventional motor unit.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuhiko Tanaka 1-5-50 Kugenuma Shinmei, Fujisawa-shi, Kanagawa F-term in NSK Ltd. (reference) 2H045 AA07 AA13 AA49 DA41 3J011 AA02 AA04 BA04 BA10 CA02 5H605 AA04 AA05 BB05 BB19 CC01 CC02 CC03 CC10 DD05 EA06 GG01 5H607 AA04 AA14 BB01 BB07 BB17 CC01 DD03 DD08 DD09 DD14 FF12 JJ04

Claims (1)

[Claims] 1. A motor unit for rotating a mounted object mounted on a support member, wherein the mounted object is fastened to the support member by a screw or the like, and a gap between an inner peripheral surface of the mounted object and the support member is provided. A motor unit characterized in that a gap is provided and an adhesive is filled in the gap.