JP2845313B2 - How to adjust the balance of a hollow rotating body - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow rotary member such as an air magnetic bearing type optical deflector used in a laser beam writing system of a laser printer, a digital copying machine or the like. The present invention relates to a method for adjusting the balance of a hollow rotating body for adjusting a weight balance. 2. Description of the Related Art FIG. 12 shows an air magnetic bearing type optical deflector according to a conventional example. Numeral 11 denotes a hollow rotary shaft, on which a magnet holding portion 12 is screwed. Also, the magnet holding unit 1
A magnet (permanent magnet) 13 is fixed to 2. 11a
Is a rotating shaft flange, and the rotating shaft flange 11a and the mirror retainer 14 clamp and fix a polygon mirror 15 fitted on the hollow rotating shaft 11. Reference numeral 16 denotes a rotor magnet which is fitted on the hollow rotary shaft 11, and these rotor magnets together constitute a rotor. [0003] The fixed shaft 1 on which the hollow rotary shaft 11 is fitted.
7 also fixes the magnet 19 to the magnet holding part 18 at the upper end.
The lower end is firmly fixed to the pedestal 20 by a method such as press-fitting or shrink fitting. Further, two pairs of upper and lower leading bone grooves 17a and 17b are formed on the surface of the fixed shaft 17 to form a bearing. In the above configuration, when the rotating body starts rotating, the rotating shaft 11 and the fixed shaft 1
The pressure in the gap 7 is increased, and a dynamic pressure bearing is formed by the increased pressure, and the rotating body is supported in a non-contact manner. On the other hand, the thrust magnetic bearing includes an upper end of the rotating shaft 11, an upper end of the fixed shaft 17, and an upper cover 2 of the case 21.
2 are constituted by magnets 13, 19, and 23 provided respectively. The magnetic poles of the magnets 13, 19, and 23 have surfaces of the same polarity facing each other, and the magnet 13 receives a repulsive force from above and below, whereby the rotating body is supported in a floating state without contact. The motor section is of an inner rotor type, and includes a rotor magnet 16 and a coil section 24. Reference numeral 25 denotes a Hall element for detecting the position of the rotor magnet 16, which also serves as speed detection, and is controlled by a control circuit (not shown). [0006] In the air magnetic bearing type optical deflector configured as described above, when the rotating body including the rotating shaft 11 rotates at a high speed, if each member is eccentric in the axial direction, rotational shake occurs. In general, in a device having a rotating body, there has been known a device for correcting the balance by screwing in a screw for correcting the balance. For example, Japanese Unexamined Utility Model Publication No. 61-187007 proposes a technique in which a screw for correcting balance is screwed into the outer periphery of a rotary drum. Further, a technology for providing a groove concentrically with respect to the central axis on the upper surface (side surface) or the bottom surface (side surface) of the rotary polygon mirror and bonding a balance weight to the groove to correct the balance is disclosed in Japanese Utility Model Application Laid-Open No. 61-19342.
No. 1 discloses this. However, in the prior art disclosed in Japanese Utility Model Laid-Open Publication No. 61-187007, the screw is simply screwed in and not fixed to the rotating drum. However, there has been a problem that the screw moves due to vibration or centrifugal force at the time of ultra-high speed rotation, and the balance of the rotating drum is lost. Further, there is a drawback that the cost is increased because a screw hole is required to be formed on the outer peripheral surface of the rotary drum. Furthermore, if the rotating body is a hollow shaft material, chips and the like during screw hole processing may enter the hollow portion, and it is necessary to clean the chips to avoid this. Further, the prior art disclosed in Japanese Utility Model Laid-Open Publication No. Sho 61-193421 has a drawback that when rotating at a high speed of 20,000 to 30,000 rpm, the balance weight is peeled off by centrifugal force. SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for adjusting the balance of a rotating body, which can solve the above-mentioned conventional drawbacks and can easily perform a highly reliable balance correction at low cost. Another object of the present invention is to provide a balance adjustment method that allows processing without cutting chips entering the hollow portion. [0011] The above object is achieved by providing a dynamic pressure inward.
In a method for adjusting the balance of a rotating body for correcting an imbalance in weight balance of a hollow rotating body having a bearing surface, a balance ring having a guide groove formed in a circumferential direction of an outer peripheral portion is formed on an outer periphery of the hollow rotating body. And mounting the hollow rotary body on a jig having a receiving seat having an outer diameter smaller than the outer diameter of the balance ring so that the side surface of the balance ring is in contact with the jig, and fixing the hollow rotary body with a chuck. Touch the tip of the cutting tool to the guide groove of the rotating body,
This is achieved by guiding the tip of the cutting tool to the balance correction position of the guide groove of the fixed rotating body, and cutting with the cutting tool while being guided by the guide groove. According to the above construction, the tip of a cutting tool, for example, a drill is guided in the guide groove, the tip position is defined, and the unbalanced portion (heavy one) is scraped off by the drill. Can be balanced and balanced. Further, a small diameter outer diameter than the outer diameter of the balance ring
When the hollow rotating body is placed on the jig on which the seat of the balance ring is in contact so that the side surface of the balance ring abuts and is fixed by the chuck, the chips fall down without sticking to the seat side when chips come out. I do. This can prevent dusts such as chips from entering between the seat and the balance ring during processing. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of a rotating body portion including a rotating shaft 11 of an air magnetic bearing type optical deflector according to one embodiment of the present invention, which is the same as or similar to the conventional example shown in FIG. The same reference numerals are given to the places to be made. In the figure, reference numerals 26 and 27 denote hollow rotary shafts 11.
It is a balance ring fitted to. The balance rings 26, 27 are formed with ring-shaped grooves 26a, 27a for drill guide on the outer peripheral portion thereof, respectively. 2 and 3 are a side view and a plan view of the balance ring 26 or 27. FIGS. 4 to 8 are cross-sectional views taken along the line AA in FIG. 3, and the shape of the grooves 26a, 27a may be wedge-shaped, concave, or hemispherical as shown in these figures. Absent. As shown in FIG. 9, the grooves 26a, 27a
May be plural. FIGS. 10 and 11 are a plan view and a partial vertical cross-sectional view of the entire apparatus at the time of the balance correcting step, in which the rotating shaft 11 is mounted on a ring-shaped balance correcting jig 28 and is shown. It is chucked and fixed by a chuck member that does not. Rotary shaft receiving seat 28 of balance correcting jig 28
The outer diameter of “a” is formed smaller than the outer diameter of the balance ring 27 on the receiving side in order to prevent cutting powder and the like from entering. In this case, the drill is guided from the direction of the arrow to the groove 27a of the balance ring 27, and the balance ring 27 is appropriately cut by rotation of the drill. The same applies to the balance ring 26 side. Since the polygon mirror 15 is incorporated in the cutting, it is preferable to perform so-called suction shaving, which is performed while sucking the cutting powder, so that the cutting powder does not adhere to the mirror surface. According to the above embodiment, the balance correcting jig 2
8, the outer diameter of the receiving seat 28a of the rotating shaft 8 is formed smaller than the outer diameter of the balance ring 27 on the receiving side, and the receiving seat 28a and the balance ring 27 are brought into close contact with each other and fixed by a chuck to cut the balance. Is performed, no cutting powder remains on the upper surface of the receiving seat 28a, and the clean state is always maintained. Therefore, even if the rotating body is replaced and the balance is repeatedly corrected, the cutting powder remaining in the receiving seat 28a does not adhere to the rotating body, thereby preventing the cutting powder from entering the hollow rotary shaft. Can be. Therefore, by using such a balance correcting jig 28, it is possible to prevent dust such as cutting powder from entering the inside of the hollow rotary shaft 11. As described above, according to the present invention,
No thread hole processing is required, so the cost of the balance ring is low, and because the groove does not cause the displacement of the drill, accurate balance correction can be easily performed, and the balance is lost because no screws or balance weights are used. And the reliability can be improved. Further, it is possible to prevent dusts such as cutting chips from entering between the seat and the balance ring at the time of machining, and it becomes unnecessary to clean the hollow portion.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a main part of an air magnetic bearing type optical deflector according to one embodiment of the present invention. FIG. 2 is a side view of a balance ring. FIG. 3 is a plan view of a balance ring. 4 is a sectional view taken along line AA in FIG. 3, showing a sectional shape of a guide groove. 5 is a sectional view taken along line AA in FIG. 3, showing a sectional shape of a guide groove. FIG. 6 is a sectional view taken along line AA in FIG. 3, showing a sectional shape of a guide groove. FIG. 7 is a sectional view taken along line AA in FIG. 3 showing a sectional shape of a guide groove. FIG. 8 is a sectional view taken along line AA in FIG. 3 showing a sectional shape of a guide groove. FIG. 9 is a side view of a balance ring according to another embodiment. FIG. 10 is a plan view of a balance correcting jig. FIG. 11 is a partially longitudinal side view showing a state of a balance correcting step. FIG. 12 is a longitudinal sectional view showing an air magnetic bearing type optical deflector according to a conventional example. [Description of Symbols] 11 Hollow rotating shafts 13, 19, 23 Magnets 26, 27 Balance rings 26a, 27a Groove 28 Balance correcting jig 28a Receiving seat 29 Chuck member

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-259510 (JP, A) JP-A-62-6133 (JP, A) Actually open JP-A-63-105475 (JP, U) (58) Field (Int.Cl. ⁶ , DB name) G01M 1/34 F16F 15/34 G02B 26/10 102

Claims (1)

(57) In the balancing method of the rotating body for correcting the imbalance of the weight balance of <br/> idling body in the hydrodynamic bearing surface inside All Claims is formed, the outer peripheral portion It said balance ring balance ring which a guide groove is formed circumferentially on the hollow attached to the outer periphery of the rotating member, before Symbol balance ring diameter outer diameter of the seat is on the formed jig than the outer diameter of the and fixed by the chuck put the hollow rotating body as the side surface of abuts, against the tip of the cutting tool in the guide groove of the fixed and rotational body, balance correction position of the guide groove of the fixed rotary body cutting tool tip to guide the, cutting by the cutting tool in a state of being guided by the guide groove, this hollow rotating body balancing method characterized by the.