CN1476010A - Method of improving ball balancing position in ball automatic balancing system - Google Patents

Abstract

A method for improving the balance position of the balls in an automatic ball balancing system used for optical disc drive, which has a rotor mechanism consisting of mainshaft motor, a rotor with ring slot, and balls in said ring slot, features that said ring slot has a surface with low friction coefficient and the rotation speed at which rotor is stable and the system phase angle of ball when rotor is stable are changed for higher balancing effect.

Description

Improve the method for ball balancing position in ball automatic balancing system

Technical field

The present invention relates to a kind of ball automatic balance system of CD-ROM drive rotating machinery, especially refer to a kind of method of improving ball balancing position in ball automatic balancing system, the resistance of motion of the ring track surface by reducing the ball gravity direction, with the stabilized (steady-state) speed that changes rotor and the ball system phase angle when reaching this rotating speed, increase the counterbalance effect of ball automatic balance system.

Background technology

Progress along with optical information access medium technique, the reading speed that is applied to the CD-ROM drive (optical diskdrive) of computer peripheral equipment presents development fast, even to this day, Spindle Motor (spindle motor) rotating speed surpasses 10,000 commentaries on classics, and (10,000RPM) Yi Shang CD-ROM drive gradually becomes the main product in market.

When Spindle Motor during with high rotation speed operation, the centrifugal force that is produced because of the disc unbalance amount also increases thereupon, and causes problems such as vibration and noise.In the practical application of CD-ROM drive, excessive vibratory output can cause optical head to read the instability of sheet ability, makes CD-ROM drive can't maintain maximum speed and reads data.In addition, with regard to the user of CD-ROM drive, the noise when CD-ROM drive runs up also causes discomfort and the puzzlement in the use.Therefore, how effectively suppress vibration, can be to guarantee CD-ROM drive in the smooth-going and accurate data that reads on the discs of high speed, be all CD-ROM drive manufacturers one of the difficulty that must overcome.

Traditionally, for reducing CD-ROM drive when running up, because of the uneven vibrations that cause of rotary machine rotor, invented a kind of ball automatic balance system, utilize the method that adds balance mass, directly lower the amount of unbalance of vibration, therefore on vibration damping, produce good effect.

The employed automatic balancing arrangement of CD-ROM drive manufacturing plant now, be (or below) adding one ball automatic balance system above Spindle Motor, the principle that the ball of this ball automatic balance system reaches the equilibrium position is to utilize the theory of spin dynamics (rotor dynamics), shown in Figure 1A to Fig. 1 C, wherein, 1 is system's centroid trajectory, 2 is the position of ball, 3 is the position of amount of unbalance, and 4 for arriving the position of the preceding ball of this state, as principal axis motor rotation speed ω _tBe lower than free-running frequency (natural frequency) and (or claim suspension system free-running frequency ω _n) time, shown in Figure 1A, system's amount of unbalance and system's barycenter are at synchronous state; As principal axis motor rotation speed ω _tEqual free-running frequency ω _nThe time, system's amount of unbalance and system's barycenter are the phase differential (shown in Figure 1B) that is 90 degree; As principal axis motor rotation speed ω _tGreater than free-running frequency ω _nThe time, system's amount of unbalance and system's barycenter then are the phase differential (shown in Fig. 1 C) of 180 degree.

Yet in practical application, because of restriction such as the influences such as circularity, sphericity and surfaceness that are subject to processing machinery and make, when making the Spindle Motor rotation of CD-ROM drive, its ball has the bigger resistance of motion.Thereby make rotor (or Spindle Motor) when reaching stabilized (steady-state) speed, system phase angle when ball can't reach this stabilized (steady-state) speed (less than unstable critical rotary speed), to such an extent as to system phase angle and the theoretical value of the position of ball when stabilized (steady-state) speed still has certain gap, so this automatic-balancing system and perfection not as being predicted in theory.

As known from the above, above-mentioned existing CD ROM disc automatic-balancing system on reality is used, obviously has some defectives and exists, and remain further to be improved.

Summary of the invention

Purpose of the present invention, provide a kind of method of improving ball balancing position in ball automatic balancing system, by reducing the resistance of motion of ball, and change the stabilized (steady-state) speed of rotor and the system phase angle that rotor reaches ball when stablizing simultaneously, reach the counterbalance effect that increases ball automatic balance system.

Another object of the present invention, provide a kind of method of improving ball balancing position in ball automatic balancing system, utilize the material of low-friction coefficient to fit or coat on the ring rail of ball gravity direction, so that reduce the ball and the resistance of motion of encircling rail, make rotor speed reach when stablizing, reach ball system phase angle, to reach better counterbalance effect.

To achieve these goals, the invention provides a kind of method of improving ball balancing position in ball automatic balancing system, wherein this ball automatic balance system is the rotor mechanical that is applied to CD-ROM drive, this rotor mechanical is to include a Spindle Motor and by rotor that this Spindle Motor drove, this rotor is concaved with coaxial ring rail, and settle ball in this ring rail to produce self-poise, and provide a low-friction coefficient ring track surface in the gravity direction of this ball, to reduce the resistance of motion of ball and ring rail, the ball system phase angle when changing the stabilized (steady-state) speed of rotor and rotor simultaneously and reaching stabilized (steady-state) speed.

The aforesaid method of improving ball balancing position in ball automatic balancing system, wherein, described low coefficient of friction surfaces is the bottom surface that fits in this ring rail in the mode of fitting.

The aforesaid method of improving ball balancing position in ball automatic balancing system, wherein, described low coefficient of friction surfaces is to coat the bottom surface of this ring rail in the mode of coating.

The aforesaid method of improving ball balancing position in ball automatic balancing system, wherein, described low coefficient of friction surfaces is a polytetrafluoroethylmaterial material.

The invention has the beneficial effects as follows, by fit or the material of coating low-friction coefficient on the ring rail of ball gravity direction, increase the counterbalance effect of ball automatic balance system.

The invention will be further described below in conjunction with the drawings and specific embodiments.

Description of drawings

Figure 1A is the synoptic diagram () that the prior art ball reaches the equilibrium position principle;

Figure 1B is the synoptic diagram (two) that the prior art ball reaches the equilibrium position principle;

Fig. 1 C is the synoptic diagram (three) that the prior art ball reaches the equilibrium position principle;

Fig. 2 is the synoptic diagram of the rotor mechanical of CD-ROM drive of the present invention;

Fig. 3 is the synoptic diagram of ball automatic balance system mathematical model of the present invention;

Fig. 4 is a frequency response chart of the present invention;

Fig. 5 is phase delay figure of the present invention.

Embodiment

As shown in Figure 2, ball automatic balance system of the present invention is placed in Spindle Motor 10 tops (or below), its structure comprises the rotors 11 that can rotate synchronously with this Spindle Motor 10, this rotor 11 is the discoid body that an opening makes progress, and be concaved with coaxial rings rail 12 on it, this ring rail 12 is the groove shape, is provided with ball 13 in addition in this ring rail 12.This ball 13 can be along the free movement of ring rail in this ring rail, to constitute a ball automatic balance system; When CD-ROM drive rotated, this Spindle Motor 10 drove discs by this rotor 11 and rotates.When the rotating speed of rotor 11 during between free-running frequency and unstable critical rotary speed, the system phase angle of ball will will obviously reduce at the vibratory output of stable region fluctuation and entire system.So ball 13 moves to the equilibrium position.

In this ball automatic balance system, suppose that the resistance of motion of this ball 13 is directly proportional with positive force, then:

F＝μ ₁N ……(1)

Wherein, μ ₁Be resistance of motion coefficient, N is a normal pressure.

As shown in Figure 3, be the synoptic diagram of ball automatic balance system mathematical model, O _CBe ball and the contact point that encircles rail, O _bIt is the barycenter of ball; Or is the barycenter of total system, and it at tangential direction ball equilibrium equation is: $m[\frac{{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="A0212789600121.png"\; state="\{\{state\}\}">d</figure-callout>}}^2}{{\mathrm{dt}}^2}\stackrel{\&OverBar;}{O_R{O}_r}+(\stackrel{\&CenterDot;\&CenterDot;}{\mathrm{\&beta;}}+\stackrel{\&CenterDot;\&CenterDot;}{\mathrm{\&phi;}})\&times;R]=-{\mathrm{\&mu;}}_{1}m(\stackrel{\&CenterDot;}{\mathrm{\&phi;}}\&times;\stackrel{\&CenterDot;}{\mathrm{\&phi;}}\&times;R+2\stackrel{\&CenterDot;}{\mathrm{\&beta;}}\&times;\stackrel{\&CenterDot;}{\mathrm{\&phi;}}\&times;R-\stackrel{\&CenterDot;}{\mathrm{\&beta;}}\&times;\stackrel{\&CenterDot;}{\mathrm{\&beta;}}\&times;r)$

Wherein, m: ball quality;

R: ring rail radius;

β: amount of unbalance is with respect to the angle of absolute coordinates;

φ: the relative angle of ball and amount of unbalance;

R: rotary body radius;

And order $\frac{{\mathrm{<figure-callout\; id="2"\; label="d"\; filenames="A0212789600121.png"\; state="\{\{state\}\}">d</figure-callout>}}^2}{{\mathrm{dt}}^2}\stackrel{\&OverBar;}{O_R{O}_r}=\stackrel{\&CenterDot;\&CenterDot;}{x}$

Then $\stackrel{\&CenterDot;\&CenterDot;}{x}\sin \mathrm{\&psi;}+(\stackrel{\&CenterDot;\&CenterDot;}{\mathrm{\&beta;}}+\mathrm{\&phi;})R={\mathrm{\&mu;}}_{1}r{\stackrel{\&CenterDot;}{\mathrm{\&beta;}}}^2-{\mathrm{\&mu;}}_{1}R{\stackrel{\&CenterDot;}{\mathrm{\&phi;}}}^2-2{\mathrm{\&mu;}}_{1}R\stackrel{\&CenterDot;}{\mathrm{\&beta;}}\stackrel{\&CenterDot;}{\mathrm{\&phi;}}$

Cause $\stackrel{\&CenterDot;}{\mathrm{\&beta;}}\&CenterDot;\stackrel{\&CenterDot;}{\mathrm{\&phi;}}\&le;0$

And $\left|\stackrel{\&CenterDot;}{\mathrm{\&beta;}}\right|>\left|\stackrel{\&CenterDot;}{\mathrm{\&phi;}}\right|$

So accelerate to certain rotating speed (greater than free-running frequency) and keep under the situation of certain rotating speed at this rotor 11, if meet following inequality, then this ball 13 can produce with respect to the constant angular velocity of this ring rail 12 and move: $\stackrel{\&CenterDot;\&CenterDot;}{x}\sin \mathrm{\&psi;}>{\mathrm{\&mu;}}_{1}r{\stackrel{\&CenterDot;}{\mathrm{\&beta;}}}^2---\left(2\right)$

Definition $\stackrel{\&CenterDot;}{\mathrm{\&beta;}}=w,$ Equation (2) can be rewritten into: $G\left(w\right)>\frac{{\mathrm{M\&mu;}}_{1}r}{\sin \mathrm{\&psi;}}---\left(3\right)$

Wherein, M is a mass of system, and G (w) is the rotor-support-foundation system frequency response;

We define w ₂Be the unstable critical rotary speed of ball, definition w _nBe the suspension system free-running frequency,, then can in frequency response chart, find w if under the enough big situation of G (w) ₂

As shown in Figure 4, be frequency response chart of the present invention, under the little situation of the resistance of motion of ball 13 and ring rail 12, w ₂/ w _nBe 1.7.Under the big situation of the resistance of motion of ball 13 and ring rail 12, w ₂/ w _nBe 1.13.So spin 13 is littler with the resistance of motion of ring rail 12, w ₂With w _nRatio big more.That is to say, if the friction of motion of ball 13 and ring rail 12 reduces the unstable critical rotary speed w of rotor 11 then ₂Increase and the vibratory output minimizing.Rotor 11 can reach higher rotation speed, and produces less vibratory output.At this moment, if the rotating speed of rotor 11 continues to increase above the unstable critical rotary speed w of this ball ₂, the vibratory output of ball and rotor-support-foundation system integral body will reduce gradually and rotor 11 can reach more high stable rotating speed.

As shown in Figure 5, be phase delay figure of the present invention, therefore when the resistance of motion of ball 13 and ring rail 12 more hour, w ₂/ w _nBigger than.Rotor 11 under this rotating speed, ball reach equilibrium state the phasing degree that must supply can be littler.Otherwise, then must the phasing degree will heal greatly.If at gravity direction sliding friction is arranged, then equation (3) must be rewritten as: $G\left(w\right)>\frac{M{\mathrm{\&mu;}}_{1}r+{\mathrm{\&mu;}}_2(g+a)}{\sin \mathrm{\&psi;}}---\left(4\right)$

Whereby, from frequency response chart (as shown in Figure 4) and phase delay figure (as shown in Figure 5), can learn the unstable critical rotary speed w of ball 13 ₂Change because of the friction force of ball 13 gravity directions, and therefore the system phase angle of ball 13 and equilibrium position also change.

So, provide a low coefficient of friction surfaces on the ring rail 12 of these ball 13 gravity directions, to solve the problem of the friction force that reduces these ball 13 gravity directions, and can utilize and fit or the mode of coating places the material of low-friction coefficient on the ring rail 12, the surface of low-friction coefficient is provided for the bottom surface of encircling rail 12, so that can reduce the resistance of motion of 12 on ball 13 and ring rail, and the rotor stability rotating speed of ball automatic balance system is raise, and rotor when quickening so far stabilized (steady-state) speed ball reach the system phase angle, increase the counterbalance effect of ball automatic balance system whereby, the surface of this kind low-friction coefficient can be that teflon (Teflon) or other materials are made, can fit in orbit, perhaps coating (coating) in orbit.

In sum, the present invention is real in improving existing CD ROM disc automatic-balancing system, utilize the friction factor that changes ball gravity direction surface of contact with the stabilized (steady-state) speed that changes rotor and reach ball phasing degree when stablizing.Can increase the counterbalance effect of ball automatic balance system.

The above only is the detailed description of a preferred embodiment of the present invention, and feature of the present invention is not limited thereto, and claim of the present invention should be as the criterion with the scope of following claims.

Claims (4)

1, a kind of method of improving ball balancing position in ball automatic balancing system, this ball automatic balance system is applied to the rotor mechanical of CD-ROM drive, this rotor mechanical includes a Spindle Motor and by rotor that this Spindle Motor drove, this rotor is concaved with coaxial ring rail, the built-in ball that is placed with of this ring rail, to produce self-poise, it is characterized in that, provide a low coefficient of friction surfaces on this ring rail of this ball gravity direction, to reduce the resistance of motion between this ball and this ring rail, and the system phase angle when changing the rotor stability rotating speed of this balanced system and ball simultaneously and reaching rotor stability, increase the counterbalance effect of this ball automatic balance system whereby.

2, the method for improving ball balancing position in ball automatic balancing system as claimed in claim 1 is characterized in that, described low coefficient of friction surfaces is the bottom surface that fits in this ring rail in the mode of fitting.

3, the method for improving ball balancing position in ball automatic balancing system as claimed in claim 1 is characterized in that, described low coefficient of friction surfaces is to coat the bottom surface of this ring rail in the mode of coating.

4, the method for improving ball balancing position in ball automatic balancing system as claimed in claim 1, it is characterized in that: described low coefficient of friction surfaces is a polytetrafluoroethylmaterial material.

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