JPS61205834A - Rotor - Google Patents

Abstract

PURPOSE:To make it possible to avoid the seizuring of a bearing due to chips, by adhering and fixing a membrane, which seals the cut mark formed to a balance corrected surface by cutting processing, to a rotor after the correction of balance. CONSTITUTION:Holes 6a is provided to the end surface of a balance ring 6 by a drill in order to correct balance and, in the similar way, drill holes 4a are also provided to a balance ring 4 by a drill. Further, seal members 16, 17 made of label paper, which comprises an annular plate materials of which the inner diameters are externally fitted to a sleeve 2 and the outer diameters are respectively smaller than the outer diameters of the rings 4, 6 and the single surfaces are coated with an adhesive, are mounted. By adhering the adhesive applied surfaces of the members 16, 17 to the end surfaces of the rings 6, 7, the drill holes 4a, 6a are covered. By this method, the seizuring of the bearing due to chips can be avoided. Especially, when a dynamic pressure fluid bearing is used, the dynamic balance correction by cutting and the mass production of a rotor are enabled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] "Industrial Application Field" The present invention relates to a rotating body that requires high speed and high precision and uses a fluid bearing.

"Prior Art" In recent years, the number of motors that require high-speed and high-precision rotation has increased. For example, a motor for a VTR head, a laser scanning motor for a laser beam printer, etc. In order to fully satisfy such high-speed, high-precision requirements, supporting the rotating body with ball bearings as in the past has become difficult in terms of accuracy, lifespan, and noise. Printers are beginning to adopt a system in which rotation is supported by hydrodynamic bearings, as shown in the fourth figure.

To explain Fig. 7, a groove pattern such as a spiral groove or a herringbone groove is formed on the surface of the shaft pressed against the cover coat λ which is fitted and fixed to the motor case ll through an O-ring itt. (Illustrated). The sleeve is fitted with the shaft with a radial gap of 2 to 70 μm to form a bearing portion.

A magnet 3, a polygon mirror 3, and a balance ring 弘μ are attached to the sleeve λ, and a thrust plate g having a small hole 7 in the center is press-fitted into the sleeve λ. A window glass 13 for laser input/output is bonded to the edge of an opening provided in the motor case // into which the stator 9 is fitted and fixed. Input/output of electrical signals inside and outside of the motor case 1 is via a connector pin/4t that is glued and penetrates the motor case 1.

It is carried out by lyo. The cap/a is attached to the motor case/l via an O-ring 20.

In this way, the motor has a sealed structure. A stable rotation speed can be obtained by detecting the phase and rotation speed of the motor using a fixed Hall element 10, and applying PLL control while supplying a drive current to the stator.

Now, when the motor is rotating, air enters the bearing from the open end of the sleeve as shown by the arrow due to the action of the ring bone groove formed on the shaft surface, and exits from the small hole 7 of the thrust plate g at the upper end of the sleeve. To go. As mentioned above, the bearing clearance is only 1 to 10 .mu.m, so the presence of dust in the air is extremely fatal, and therefore the motor also has a sealed structure as mentioned above.

On the other hand, in order to ensure high-precision rotation, it is necessary to correct the dynamic unbalance of the rotating body because it causes negative effects such as vibration and whirling of the rotating body. In the past, the unbalance was corrected by applying a lead-containing co-component mixing board epoxy adhesive to the opposite side of the unbalanced position.

"Problems to be Solved by the Invention" This method has the following problems: (1) At high speed rotation, the adhesive is deformed or scattered due to centrifugal force, resulting in a change in the unbalance amount.

(,2) It is difficult to supply a fixed amount of adhesive for adhesion resistance.

(J) The viscosity of the adhesive is high, and it takes time to mix the components evenly.

In particular, if you try to increase the strength and hardness of the adhesive, the curing time will become longer, and if you try to increase productivity (
1) could no longer be satisfied, and (1) and (3) were contradictory problems, which became a major obstacle in promoting automation of mass production of motors.

On the other hand, dynamic balance correction by cutting with a drill has been established as the most common method in promoting automation, but when cutting with a drill, it is inevitable that chips will be generated, and the generation of chips is due to the axis ◆ This can be a fatal injury for some people.

As explained above, in conventional motors, the rotating body is supported by dynamic pressure fluid bearings, so when mass production is carried out to correct dynamic imbalance, an appropriate means can be obtained and mass production can be carried out without delay. The transition was not possible.

The present invention eliminates such problems in dynamic balance adjustment of a rotating body, corrects the balance by cutting, and fixes the thin film sealing member that seals in the generated chips without disturbing the balance. The object of the present invention is to provide a method for adjusting the balance of a rotating body by which a solid rolling body that does not scatter can be obtained.

[Structure of the invention]

"Means for Solving Problems" The present invention provides a rotating body having a balance correction surface for removing and correcting dynamic unbalance caused by rotation by cutting. This rotating body is characterized in that a thin film that encapsulates cutting marks formed on the rotating body is attached and fixed to the rotating body after balance correction.

``Operation'' Since the extremely lightweight thin film seals the cutting marks formed on the balance correction surface, the amount of unbalance generated by the thin thin film is extremely small, so work can be done without considering the unbalance caused by the addition of the thin film. And the chips can be contained in the cutting marks.

"Example" Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, in which a hole 6a is drilled in the end face of a balance ring 6 for balance correction. Similarly, it is not visible in the balance ring, but the drill hole lII! L is open. /6. The l is a circular plate material whose inner diameter fits into the sleeve co and whose outer diameter is within the outer diameter of the balance ring, and is made of polyester film, aluminum foil, titanium foil, beryllium copper plate, etc. with adhesive on one side.
This is a sealing member made of extremely thin label paper, etc. After the balance correction by cutting, this sealing member /lb, /7
Drill a hole by gluing the adhesive-applied side to the end of the balance ring! IL and AN are covered.

Of course, during cutting, all areas other than the cutting surface must be completely covered with wood, and all possible measures against chips must be taken, such as constantly sucking chips from the vicinity of the drill during machining and not using cutting oil.

In addition, as shown in the figure, the head of the machine screw L (see Figure D), which is inserted through the holes of the balance ring 6 and the polygon mirror 3 and screwed into the sleeve, is provided with a counterbore so that the head of the machine screw L can be placed on the surface to which the seal is attached. It is desirable to have a configuration that eliminates protrusions like this.

The weight of the sealing member is, for example, approximately -g■ when a polyester tape made of a polyester film of 23 .mu.m and an adhesive of approximately .lambda. to .mu.m is formed into a ring shape with an inner diameter .psi./Km and an outer diameter .psi. 30 m.

Assuming that the weight of the rotating body is approximately 30,011, and the amount of unbalance correction at the moss point is at the same distance from the center of gravity, the seal member/4. The deviation in the radius of the eccentric center of gravity caused by attaching /7 with an eccentricity of o, rm is -g X 10 X O,! l://! 0:0. /
X 10 (μm) This means that the rotating body is λθOθθrpm
If it is rotated at the same speed, the unbalance is half that of the 631809 class. Therefore, it can be said that there is no practical problem at all. In order to further reduce the unbalance caused by pasting the seal, the seal member /4./7 should be tightly fitted to the outer diameter of the sleeve.

Also, as shown in Figure 3, a seal member/7 is attached to the balance ring base.
In order to provide a portion that fits with the outer diameter, a circular protrusion 6b may be provided on the outer part of the end face of the counter, and the outer diameter of the seal member may be fitted into the inner diameter portion 6C. In this case, seal member/7
However, it can also prevent the phenomenon of peeling off from the outer periphery due to wind blowing, which is more effective.

Of course, the sealing member is not in the shape of an annular plate. For example, as shown in FIG. Even things that are pasted on the edge of the frame are dangerous.

Further, the thin film does not need to be formed by a sealing member as described above; it is also possible to form a thin film by attaching an adhesive to the cut surface or by applying a paint. In this case, unlike the seal member described above, a thin film is formed directly on the cut surface, but the effect of encapsulating the cut surface is exactly the same as that of the seal member.

Also, the weight of the adhesive at this time is 0.0. / If the thickness of IEI is enough to withstand adhesion, then it will be HIROη. Therefore, as above, the weight of the rotating body is j 0
019. If the distance from the center of gravity to both unbalance correction surfaces is equal, the radius of the eccentric center of gravity is 4' x 10 x /3/lrO": 0.cop
If the rotor is rotated at 1000 rpm, this is equivalent to 04iL class rather than J, so there is no practical problem.

The scanner motor for laser beam printers has been explained above, but it is also effective for the rotating body of motors that use fluid bearings, such as high-speed or high-precision motors for video, etc. Rotation using hydrostatic bearings is also effective. It is clear that the same applies to the body. Note that the thin film mentioned in the present invention is one that is thick enough that the imbalance caused by the film being resistant to adhesion will not cause problems to the rotating body, and the film has a thickness of approximately 0~/lfi, although it varies depending on the rotation speed. As expected.

〔Effect of the invention〕

As described above, the present invention can avoid seizure of the bearing due to chips by forming a thin film that encapsulates the cut surface. Particularly when a hydrodynamic bearing is used, it is possible to correct the dynamic balance by cutting, making it possible to mass-produce rotating bodies. The amount of unbalance caused by the sealing member is extremely small, so there is no need to take it into consideration before caulking.

[Brief explanation of the drawing]

1 and 2 are respectively perspective views of the embodiment of the present invention, and FIG.
The figure is a cross-sectional view of another embodiment, and Figure D is a longitudinal cross-sectional view of the scanner motor. Da, 6・φ balance ring /6. l,/l; --Sealing member. Patent applicant: Canon Co., Ltd. Representative: Arai - Figure 1

Claims (1)

[Claims] 1. In a rotating body having a balance correction surface for removing and correcting dynamic unbalance caused by rotation by cutting, a thin film that encapsulates the cutting marks formed on the balance correction surface by cutting is used. A rotating body characterized by being attached and fixed to the rotating body after balance correction.