JPH0571547A - Bearing structure of rotary body - Google Patents

Abstract

PURPOSE:To support a bearing with high precision and carry out working and assembly in a simple manner, and obtain the bearing structure of a rotary body having the low vibration and low noise at a low cost, by installing an annular wedge member having the top edge part which is inserted toward the center sides of the upper and lower bearings, in a gap between the inner periphery of an inner race and the outer periphery of a rotary ring. CONSTITUTION:An inner race receiving part 31 as an annular or modified conical shaped wedge member which has a wedge shaped section and is integrally formed with the rotor 13 is installed between the upper side edge of the inner race 22Ab of an upper bearing 22A and the contact part 13b of a rotor 13. Further, a tapered washer 32 as an annular or deformed conical shaped wedge member having a wedge shaped section is installed between the lower side edge of the inner race Bb of a lower bearing 22B and a bent washer 26. Accordingly, the movement of a rotary shaft 18 is restrained in the radial direction, also in the axial direction, and even if a force in the radial direction is applied on the center G of gravity of the rotor 13, the turning-down of the rotary shaft 18 is suppressed, and the variation of the balance through the lapse of time can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing structure of a rotating body, for example, a rotating body of a rotating portion of a polygon scanner motor used as a rotating and polarizing means of a light beam such as a laser beam printer and a digital copier.

[0002]

2. Description of the Related Art In recent years, laser printers, digital copiers, and the like, which were once limited to use in only a part of a large computer as a high-speed, high-quality image forming apparatus, have made recent breakthroughs in technology. Along with the increase in the density and speed of the output image, the size and weight of the output image have been reduced.
As an A-equipment, it has expanded into the field of offices.

Such a laser printer has a structure shown in FIG.
As shown in, a polygon scanner 1 provided with a rotary polygon mirror 2 for beam deflection is provided. The polygon scanner motor 3 for rotating the rotary polygon mirror 2 also tends to be speeded up and downsized in accordance with the speeding up and weight saving of the main body device. Further, it is necessary to suppress the trouble of the polygonless scanner that affects the print quality, and the dimensions of the related parts are required to have higher precision. Above all, the dimensions of the rotating shaft 4A of the rotor 4 that is a rotating body that supports and rotates the rotating polygon mirror 2 and the bearings that support the rotating shaft 4A are as follows.
In particular, high precision is required.

In the conventional bearing structure 5 for a rotating body, as shown in FIGS.
As shown in FIG. 3, the rotary shaft 4A fixed to the rotor 4 includes vertical bearings 7A and 7B (typically, 7A and 7B, which are vertically arranged inside the housing 6 to which the plate-shaped stator 5A is fixed and are axially separated from each other. It is rotatably supported via. Inner rings 7a of the upper and lower bearings 7A and 7B are axially urged by a bending washer 8 toward the bearing 4a side of the rotor 4, and the bending washer 8 is locked by a retaining ring 9 fixed to the rotating shaft 4A.

When the polygon scanner motor 3 is made smaller and thinner, the center of gravity of the rotor 4 is lowered and the center of gravity G is located near the upper bearing 7A. For this reason, the presence or absence of a gap between the bearing and the rotating shaft 4A greatly affects the balance change of the rotor 4 and the like. FIG. 4b shows a model of the shaft and the bearing. As the miniaturization progresses in this way, the bearing spacing L cannot be made large. Among them, the clearance ε between the shaft and the bearing inner ring must be made smaller in order to make the inclination θ of the rotating shaft 4A or the tilting less than the required value, which is becoming more severe. Further, because the gap 10 changes the balance during rotation with time, it is necessary to make the gap 10 as small as possible in terms of vibration and noise.

As a means for reducing the gap between the rotating shaft 4A of the rotating body and the bearing 7 and improving the accuracy of the rotating shaft, the bearing and the bearing, the following ones have been proposed. ing. What is described in JP-A-2-286917 is
A leaf spring is provided between the shaft and the bearing, and the bearing is pressed in any direction to remove the gap between the shaft and the inner ring of the bearing.

An adhesive is inserted in the clearance between the shaft and the bearing to fix the shaft and the inner ring. The dimensions of the shaft and the bearing are classified and combined so that the clearance between the shaft and the bearing is as small as possible.

[0008]

However, in the above-mentioned prior art, not only the leaf spring for pressing the bearing and the leaf spring mounting mechanism are required, but also the assembling work of these is not required. There is a problem that it becomes complicated. Further, in the above, since the adhesive is inserted into the gap, grooves and holes through which the adhesive flows are required, which makes the processing of these grooves and holes complicated and makes assembly difficult. There is. Further, in the above, since the adhesive agent and the leaf spring are not required as in the above, it is easy in this respect, but it is necessary to store the shaft and the bearing by ranking, There is a problem in that inventory of shafts and bearings classified into ranks increases and it takes time to manage the inventory.

The present invention has been made against the background of such a conventional technique. In a bearing structure for a rotating body which is downsized and has high accuracy, a space between the upper end of the inner ring of the upper bearing and the rotating body, and a lower body are provided. By inserting the tip of the wedge member into the gap between the inner ring and the rotating shaft between the lower end of the inner ring of the bearing and the urging member, it is possible to prevent the rotating shaft from falling and to provide highly accurate bearing support. A bearing structure of a rotating body that can be processed and assembled easily, can be manufactured at low cost, and uses a viscoelastic body as a wedge member to absorb generated vibration and noise and reduce vibration and noise. The purpose is to do.

[0010]

According to a first aspect of the present invention, there is provided a rotary shaft rotatably supported by upper and lower bearings axially vertically separated from each other inside the housing, and the rotary shaft. A fixed rotating body, the outer rings of the upper and lower bearings are fixed to the housing, respectively, the upper end of the inner ring of the upper bearing contacts the rotating body, and the lower end of the inner ring of the lower bearing is biased. In a bearing structure of a rotating body that is urged toward the rotating body side in the axial direction by a member, between the upper end of the inner ring of the upper bearing and the rotating body, and between the lower end of the inner ring of the lower bearing and the urging member. An annular wedge member, which is interposed in at least one of the two, is provided in the gap between the inner circumference of the inner ring and the outer circumference of the rotating shaft, the annular wedge member having a tip portion inserted toward the center side of the vertical bearing. Claim 2 of the present invention is characterized in that In the bearing structure of the rotating body, the wedge member is made of a viscoelastic body and is provided only between the upper end of the inner ring of the upper bearing and the rotating body. Claim 3 of the present invention The rotating body bearing structure according to Item 1 or 2 is characterized in that the wedge member is made of a viscoelastic adhesive.

[0011]

According to the first aspect of the present invention, rotation and inner circumference of at least one of the inner ring between the upper end of the inner ring of the upper bearing and the rotating body and between the lower end of the inner ring of the lower bearing and the urging member. The tip of the annular wedge member is inserted into the gap between the outer circumference of the shaft,
Since the urging member urges the rotor toward the rotating body, the rotation shaft is constrained from moving in the radial direction as well as in the axial direction, and the restraint is continued chronologically.

Further, according to the second aspect of the invention, since the annular wedge member is made of a viscoelastic body, axial and radial vibrations and noises are transmitted to the viscoelastic body and absorbed as internal loss. Further, according to claim 3, since the annular wedge member also serves as an adhesive used for adhering the shaft and the rotor, the cost is low, and the vibration and noise in the axial direction and the radial direction are caused by the adhesive. It is transmitted inside and absorbed as internal loss.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of a bearing structure 11 for a rotating body according to claim 1 of the present invention, which is applied to a polygon scanner motor of a laser printer. First, the configuration will be described. In FIG. 1A, 12 is a polygon scanner motor of a laser printer, the polygon scanner motor 12 has a rotor 13 which is a disk-shaped rotating body, and a ring-shaped magnet 14 is attached to the outer periphery of the rotor 13. There is. As shown in FIG. 3, a rectangular iron plate-shaped stator 15 is installed so as to face the lower portion of the magnet 14. On the plate-shaped stator 15 inside the magnet 14, a ring-shaped drive coil 16 is fixed so as to face the rotor 13, and the plate-shaped stator 15 is a polygon scanner motor 12.
Of the fixed yoke of. On the plate-shaped stator 15, not only the drive coil 16 but also ICs (not shown), chip parts, etc. are mounted.

Reference numeral 18 is a rotary shaft, and the rotary shaft 18 fixes the central portion of the rotor 13 to the upper part of the rotary shaft 18. A flange portion 13a is provided on the outer peripheral portion of the rotor 13, and a polygon mirror 19 is fixed on the flange portion 13a by a mirror retainer 20. Reference numeral 21 denotes a housing, and the housing 21 on the circular pipe has a plate-shaped stator 15 fixed to the upper side of a flange portion 21a at the center in the axial direction. Inside the housing 21, upper and lower bearings 22A, 22 which are upper and lower bearings arranged vertically apart from each other in the axial direction.
B (representative Koki is called 22) is provided and the housing
The rotary shaft 18 is rotatably supported by the upper and lower bearings 22. Outer rings 22Aa and 22Ba of the upper and lower bearings 22 are fixed to the housing 21 by steps provided vertically inside the housing 21.

Further, the upper end of the inner ring 22Ab of the upper bearing 22A abuts on the abutting portion 13b around the rotary shaft 18 of the rotor 13, and the lower end of the inner ring 22Bb of the lower bearing 22B is a rotary shaft 18.
A bending wire 26, which is an urging member locked to a retaining ring 25 fixed to, is urged toward the rotor 13 in the axial direction. The upper and lower ends of the upper and lower bearings 22 are chamfered on both the inner peripheral side of the inner ring and the outer peripheral side of the outer ring to form a conical portion 22s.

Between the upper end of the inner ring 22Ab of the upper bearing 22A and the abutting portion 13b of the rotor 13, the inner ring receiver is integrally formed on the rotor 13 and is a wedge member having a wedge-shaped cross section or a conical wedge shape. A section 31 is provided. The acute-angled tip portion 31a of the inner ring receiving portion 31 and the inner circumference of the inner ring 22Ab and the rotary shaft 18
The inner ring 22Ab is inserted into the gap between the outer periphery of the inner ring 22Ab and the conical portion 22s of the inner ring 22Ab toward the center of the two upper and lower bearings 22.

Further, between the lower end of the inner ring 22Bb of the lower bearing 22B and the bending washer 26, there is provided a tapered washer 32 which is a wedge member having an annular or irregular conical shape with a wedge-shaped cross section. Tip of tapered washer 32
32a is inserted into the gap between the inner circumference of the inner ring 22Bb and the outer circumference of the rotary shaft 18 in contact with the conical portion 22s of the inner ring 22Bb toward the center of the two upper and lower bearings 22.

The inner ring receiving portion 31 and the tapered washer 32 are urged toward the rotor 13 by the bending washer 26, and the inner ring receiving portion 31 and the tapered washer 32 are provided.
The wedge-shaped or the conical-shaped is used to fix the rotary shaft 18 to the upper and lower bearings 22 in the radial and axial directions. Next, the operation will be described.

According to the first aspect of the invention, the tip portion 31a of the inner ring receiving portion 31 and the tip portion 32a of the tapered washer 32 are located in the gap between the inner periphery of the inner ring 22Ab and the outer periphery of the rotary shaft 18, respectively. Since the upper and lower bearings 22 are inserted in contact with the conical portion 22s and the upper and lower bearings 22 are biased toward the rotor 13 by the bending washer 26, the rotation shaft 18 is restrained from moving in the radial direction as well as the axial direction. Even if a radial force is applied to the center of gravity G of 13, the tilting of the rotary shaft 18 is suppressed and the balance change over time is eliminated. Therefore, the polygon mirror 19 supported by the rotary shaft 18 is less likely to be tilted, and high quality can be achieved.

Further, since the inner ring receiving portion 31 is integrally formed with the rotor 13, the number of parts does not increase, the number of assembling steps is easy, and the cost can be reduced. FIG. 2A is a diagram showing a second embodiment of the invention described in claims 1 and 2, and the same components as those in the first embodiment are designated by the same reference numerals. In FIG. 2A, the inner ring receiving portion 41, which is a wedge member, is made of a viscoelastic body, for example, a rubber body, and the upper end of the inner ring 22Ab of the upper bearing 22A near the center of gravity G ₁₃ of the rotor 13 and the rotor 13. This is the case where it is provided separately from the rotor 13 only during the period.

In this embodiment, the inner ring receiving portion 41 is made of a rubber body and is urged toward the rotor 13 by the bending washer 26 via the lower bearing 22B, the housing 21 and the upper bearing 22A. Although the number of parts is increased by making the above separate, the inner ring receiving portion 41 transmits the vibration noise into the rubber body even if vertical vibration, noise, etc. occur due to switching of the excitation of the motor, for example. ,
It becomes an internal loss in the rubber body and is absorbed. Therefore, the polygon scanner motor 12 can be significantly reduced in vibration and noise.

FIG. 2B is a diagram showing a third embodiment of the invention according to claims 1, 2 and 3, and the same components as those in the first embodiment are designated by the same reference numerals. In FIG. 2B, the inner ring receiving portion 51, which is a wedge member, is an adhesive that is a viscoelastic body, and this adhesive is the adhesive used when the rotor 13 and the rotary shaft 18 are joined. It is used in combination. This allows the bearing 22 and the housing 21 to be assembled after the rotor 13 and the rotary shaft 18 are assembled and the adhesive is sufficiently cured.

By doing so, the number of parts does not increase, and the number of assembling steps hardly increases, which is advantageous and the cost can be further reduced. Further, even if vibration noise is generated from the motor or the like, it is transmitted to the adhesive agent, resulting in internal loss in the adhesive agent.
It can significantly reduce vibration and noise.

[0024]

As described above, according to the first aspect of the present invention.
According to this, in the bearing structure of the rotating body which is downsized and has high accuracy, the inner ring is formed between the upper end of the inner ring of the upper bearing and the rotating body and between the lower end of the inner ring of the lower bearing and the biasing member. By inserting the tip of the wedge member into the gap between the rotary shaft and the rotary shaft, it is possible to prevent the rotary shaft from falling and support the bearing with high precision. Further, according to claim 2 of the present invention, the wedge member is made of a viscoelastic body, and the generated vibration and noise can be absorbed to reduce the vibration and noise. Further, according to the invention of claim 3, By using a viscoelastic adhesive as the wedge member, the adhesive can also be used as another adhesive, the number of parts can be reduced, and the cost can be further reduced.

[Brief description of drawings]

1A and 1B are diagrams showing a polygon scanner motor to which a first embodiment of a bearing structure for a rotating body according to claim 1 of the present invention is applied, wherein FIG. 1A is an overall sectional view thereof, and FIG. It is a figure.

2A and 2B are views showing another embodiment of the bearing structure for a rotating body according to claim 1 of the present invention, in which FIG. 2A is a sectional view of an essential part of the second embodiment, and FIG. It is a principal part sectional drawing of an example.

FIG. 3 is a view showing a polygon scanner motor using a conventional rotating body bearing structure, in which (a) is an overall perspective view thereof;
(B) is the whole sectional view.

4A and 4B are views showing a main part of the polygon scanner motor shown in FIG. 3B, FIG. 4A is a cross-sectional view of the main part, and FIG.

[Explanation of symbols]

 13 rotor (rotating body) 18 rotating shaft 21 housing 22A upper bearing (upper bearing) 22B lower bearing (lower bearing) 22Aa, 22Ba outer ring 22Ab, 22Bb inner ring 26 bending washer (biasing member) 31, 41, 51 inner ring receiving part ( Wedge member) 32 Tapered washer (Wedge member)

Claims (3)

[Claims] 1. A vertical shaft comprising a rotary shaft rotatably supported by vertical bearings axially spaced apart from each other inside the housing, and a rotary body fixed to the rotary shaft. Outer rings are fixed to the housing, the upper end of the inner ring of the upper bearing abuts on the rotating body, and the lower end of the inner ring of the lower bearing is urged by the urging member toward the rotating body in the axial direction. In a body bearing structure, the inner ring is interposed between at least one of an upper end of an inner ring of the upper bearing and the rotating body and between a lower side of an inner ring of the lower bearing and the urging member. A bearing structure for a rotating body, wherein an annular wedge member having a tip portion inserted toward the center side of the upper and lower bearings is provided in a gap between the inner circumference of the above and the outer circumference of the rotary shaft. 2. The bearing structure for a rotating body according to claim 1, wherein the wedge member is made of a viscoelastic body and is provided only between the upper end of the inner ring of the upper bearing and the rotating body. 3. The bearing structure for a rotating body according to claim 1, wherein the wedge member is made of a viscoelastic body adhesive.