JP2006102918A - Manufacturing method and device for spindle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a spindle and a manufacturing device assuring low cost by establishing the configuration with a simple circuitry and capable of maintaining and enhancing the reliability. <P>SOLUTION: The manufacturing method and device 10 for the spindle use a loading means 11, exciting means 12 and 13, a fixing means 14, a vibration sensing means 18, and a control means 19, wherein the control means 19 drives the exciting means 12 and 13 by generating sine waves of resonance frequency corresponding to the specified rigidity of the spindle 50 and controls the loading means 19 on the basis of the phase value by sensing the phase of the sine wave of a vibration signal sensed by the vibration sensing means 18. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method and apparatus for manufacturing a spindle used in a control machine incorporating a spindle such as a swing arm of a hard disk device.

  Conventionally, spindles incorporated in various precision rotating parts such as spindle motors such as video tape recorders (VTRs), hard disk drives (HDDs), laser beam printers (LBPs), rotary actuators, rotary encoders, etc. In order to prevent runout, it must be manufactured with extremely high accuracy. For this reason, the spindle is used with a preload applied. By applying this preload, the rigidity of the bearing of the spindle is kept high, the shaft runout accuracy is improved, and the rolling elements are prevented from slipping during high-speed rotation.

  As an example of a conventional spindle manufacturing method and manufacturing apparatus, there is a spindle manufacturing method in which press-fitting is finished in a state where a predetermined resonance frequency is reached while measuring the resonance frequency by applying vibration to the spindle by a piezoelectric element. It is known (see, for example, Patent Document 1).

As another example of a conventional spindle manufacturing method and manufacturing apparatus, a motor is controlled and press-fitted by screw feed, a vibration for measurement is given to the spindle by a piezoelectric element, and press-fitting is performed at a predetermined resonance frequency. A method of manufacturing a spindle that is finished is known (for example, see Patent Document 2).
Japanese Patent No. 3254825 (pages 5-6, FIG. 1) Japanese Patent Laid-Open No. 2001-324253 (pages 3 to 5, FIG. 1)

  However, in Patent Document 1 and Patent Document 2 described above, in order to detect the resonance frequency of the spindle, data is obtained as a result of applying a Fourier transform to the vibration signal of the response by exciting with a sine wave having a large number or a continuously changing frequency. A method for detecting a resonance frequency is used, in which the resonance frequency is searched for. For this purpose, a large number of electronic devices such as complicated frequency generation functions, signal digital conversion (A / D conversion) functions, computers for performing these controls and Fourier transforms, and software for control and computation, However, there is a problem that it is expensive because it is necessary, and it is difficult to maintain and improve the reliability of the manufacturing apparatus and to maintain it.

  Furthermore, in the process of press-fitting, a series of processing such as A / D conversion of response vibration, calculation of Fourier transform and amplitude characteristics, and search for a peak frequency must be performed by short-term intermittent repetition. When the resonance frequency is high, processing in a wide frequency band is necessary. Therefore, it is necessary to use a computer suitable for high-speed processing or to reduce the number of data to be processed at one time. Or the accuracy of the detected resonance frequency is deteriorated. In addition, since the peak is found from the Fourier transform of one response signal and set as the resonance frequency, the resonance frequency does not coincide with the peak theoretically, particularly when the resonance Q value is not high.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a spindle that can be manufactured at low cost by being configured with a simple circuit, and that can easily maintain and improve reliability. A manufacturing method and a manufacturing apparatus are provided.

  1) A spindle manufacturing method according to the present invention includes a load means for applying a preload by relatively moving a shaft press-fitted into an inner ring of a bearing included in the spindle, and an application for applying vibration to the spindle. Vibration means, fixing means for fixing the spindle, vibration detection means for detecting vibration of at least one of the housing or outer ring fitted on the outer ring of the shaft or the inner ring and the bearing, and the load And a control means for controlling the excitation means, wherein the control means generates a sine wave having a resonance frequency corresponding to a predetermined rigidity of the spindle to generate the sine wave. The preload is set by driving the vibration means, detecting the phase of the sine wave of the vibration signal detected by the vibration detection means, and controlling the load means based on the phase value. It is set to.

  According to the spindle manufacturing method described in 1) above, the vibration detecting means is mainly composed of a relatively simple circuit for generating a single sine wave and detecting a phase difference between two signals. Therefore, it can be manufactured inexpensively with a simple circuit configuration. In addition, it is possible to easily maintain reliability and improve reliability, and even when the resonance frequency is high, continuous precise detection can be performed to set the preload.

  2) The spindle manufacturing method according to the present invention is the spindle manufacturing method described in 1) above, wherein the control means detects the sine wave vibration of the shaft or the inner ring detected by the vibration detection means, and the housing. Alternatively, when the phase difference with the sine wave vibration of the outer ring reaches 90 degrees, the load means is controlled to stop the press-fitting of the inner ring and remove the load.

  According to the method for manufacturing a spindle described in 2) above, in order to give the spindle a predetermined rigidity, only the sine wave of the corresponding resonance frequency is vibrated and press-fitted until the phase difference reaches 90 degrees. Therefore, a predetermined rigidity can be set by setting an accurate resonance frequency with a high S / N ratio even at a high frequency.

  3) The spindle manufacturing method according to the present invention is the spindle manufacturing method described in 1) or 2) above, wherein the excitation means applies a sinusoidal vibration in the axial direction to the spindle, and the vibration detection means. Is characterized by detecting at least one axial sinusoidal vibration of the shaft or the inner ring and the housing or the outer ring.

  According to the method of manufacturing a spindle described in 3) above, the axial rigidity of the spindle is applied to the spindle by the vibration means, and the axial rigidity of the spindle is detected by the vibration detection means. Can be set by a sinusoidal vibration in the axial direction.

  4) The spindle manufacturing method according to the present invention is the spindle manufacturing method described in 1) or 2) above, wherein the excitation means applies a radial sine wave to the spindle, and the vibration detection means , Detecting at least one radial sinusoidal vibration of the shaft or the inner ring and the housing or the outer ring.

  According to the method of manufacturing a spindle described in 4) above, the sine wave vibration in the radial direction is applied to the spindle by the vibration means, and the rigidity of the spindle is detected by detecting the radial sine wave vibration by the vibration detection means. Can be set by a sinusoidal vibration in the radial direction.

  5) A spindle manufacturing apparatus according to the present invention is characterized by using the spindle manufacturing method described in any one of 1) to 4) above.

  According to the spindle manufacturing apparatus described in 5) above, the vibration detecting means is mainly composed of a relatively simple circuit for generating a single sine wave and detecting a phase difference between two signals. Therefore, an inexpensive manufacturing apparatus can be obtained with a simple circuit configuration. Further, it is possible to easily maintain the reliability and improve the reliability in the manufacturing apparatus. Furthermore, even when the resonance frequency is high, continuous accurate detection can be performed and set.

  According to the method and apparatus for manufacturing a spindle of the present invention, it becomes expensive, it is difficult to maintain and improve reliability and maintenance, the accuracy of the resonance frequency detected when the resonance frequency is high, the resonance frequency peaks. The problem that they do not coincide with each other can be solved, and by constituting with a simple circuit, it can be manufactured at a low cost, and it is possible to easily maintain reliability and improve reliability.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the drawings.
FIG. 1 is an overall configuration diagram of a spindle manufacturing apparatus in which an embodiment of a spindle manufacturing method and manufacturing apparatus according to the present invention is used, FIG. 2 is an explanatory diagram of a spindle vibration model during press-fitting, and FIG. 3 is an amplitude during press-fitting. FIG. 4 is a phase characteristic diagram at the time of press-fitting, and FIGS. 5A, 5B, 5C, and 5D are transfer characteristic diagrams illustrating the shift of the resonance frequency in the press-fitting process.

  As shown in FIG. 1, a spindle manufacturing apparatus 10 according to an embodiment of the present invention includes a load device 11 that is a load means, a pair of vibrators 12 and 13 that are vibration means, and a fixing means. The press-fitting jig 14, the load cell 15, a shaft vibration sensor 16 and a housing vibration sensor 17 that are vibration detection means, a vibration detector 18, and a control device 19 that is a control means. In the spindle 50, a shaft 53 is internally fitted to inner rings (shown in FIG. 2) 52, 52 of a pair of bearings 51, 51, and a housing 55 is fitted to outer rings (shown in FIG. 2).

  The load device 11 has an upper vibrator 12 assembled on the lower surface thereof and is electrically connected to the control device 19. The load device 11 is a direct-acting load device such as a hydraulic pressure or a feed screw mechanism, and generates a predetermined pressing force toward the load cell 15 by an electric signal given from the control device 19, whereby the spindle 50 shafts 53 are relatively moved to apply preload.

  The upper pressing member 20 of the press-fitting jig 14 is assembled on the lower surface of the vibrator 12 disposed on the upper side. Since the vibrator 12 is electrically connected to the control device 19, it vibrates in the axial direction to the upper pressing member 20 by an electric signal given from the control device 19.

  The vibrator 13 arranged on the lower side has a lower pressing member 21 provided on the press-fitting jig 14 assembled on the upper surface and a lower surface assembled on the load cell 15. Since the vibrator 13 is electrically connected to the control device 19, it vibrates in the axial direction to the lower pressing member 21 by an electric signal given from the control device 19. The vibrators 12 and 13 need to be suitable for the direction of rigidity to be set on the spindle 50, that is, the direction of vibration depending on the axial direction or the radial direction, but the structure of the spindle manufacturing apparatus 10 is conceptually Here, only the case where the axial rigidity is set will be described. The vibrators 12 and 13 preferably have sufficient strength and rigidity in the axial direction. For example, a voltage element or a magnetostrictive element can be used. Further, the vibrators 12 and 13 can detect pressure input. The detected pressure input is fed back for feed rate control and can be used for measurement correction.

  The press-fitting jig 14 has a pair of an upper pressing member 20 and a lower pressing member 21. In the upper pressing jig 20, a protruding portion formed in an axial shape at the lower end is in contact with the shaft 53 of the spindle 50. The lower pressing jig 21 is opposed to the upper pressing jig 20, and a protruding portion formed in a cylindrical shape at the upper end is in contact with the end faces of the inner rings 52, 52 of the bearings 51, 51 of the spindle 50. The upper pressing member 20 presses the shaft 53 with a load applied from the load device 11 via the vibrator 12, and the lower pressing member 21 receives the bearing 51, on the load cell 15 side via the vibrator 13. The inner rings 52 and 52 of 51 are supported.

  Since the load cell 15 is disposed on the base 22 and is electrically connected to the control device 19, the load applied from the lower pressing member 21 of the press-fitting jig 14 via the vibrator 13. Is converted into an electric signal and supplied to the control device 19.

  Since the axial vibration sensor 16 is attached to the end face of the upper pressing member 20 of the press-fitting jig 14 and is electrically connected to the vibration detector 18, the vibration sensor 16 generates vibrations in the upper pressing member 20. The component is converted into an electrical signal (first signal) and supplied to the vibration detector 18. The axial vibration sensor 16 may be a fixed type such as an acceleration pickup, a stylus type such as a record needle, or a non-contact type such as a laser Doppler velocimeter.

  The housing vibration sensor 17 has a sensing portion attached to the end face of the housing 55 of the spindle 50 and is electrically connected to the vibration detector 18, so that the vibration component generated in the housing 55 is converted into an electric signal (first signal). 2) and applied to the vibration detector 18. The housing vibration sensor 17 may be a fixed type such as an acceleration pickup, a stylus type such as a record needle, or a non-contact type such as a laser Doppler velocimeter, in the same manner as the axial vibration sensor 16.

  The vibration detector 18 calculates and calculates the phase difference between the sine wave vibration given from the shaft vibration sensor 16 and the sine wave vibration given from the housing vibration sensor 17, and the phase difference data is controlled by the control device. 19

  The control device 19 performs an arithmetic process on the electrical signal given from the load cell 15, drives the load device 11 with the electrical signal generated based on the value of the phase difference data given from the vibration detector 18, and the spindle 50. A sine wave electric signal having a resonance frequency corresponding to the predetermined rigidity is generated to drive the excitation means 12 and 13. Then, when the phase difference data given from the vibration detection means 18 reaches 90 degrees, the control device 19 stops the press-fitting into the inner rings 52 and 52 and removes the load. The sine wave oscillator in the control device 19 may be either one that oscillates a fixed frequency or one that can change / set the oscillation frequency, but it is more preferable if the frequency stability is high, the distortion is low, and the noise is low. . The sine wave oscillator outputs two signals in which a DC voltage larger than the amplitude voltage is superimposed on a sine wave having a phase difference of 180 degrees as a bias to drive the respective vibrators 12 and 13.

  In such a spindle manufacturing apparatus 10, the shaft 53 of the spindle 50 contacts the upper pressing member 20 of the press-fitting jig 14, and the inner ring 52 of the spindle 50 contacts the lower pressing member 21 of the press-fitting jig 14. And while the lower part of the inner ring 52 is supported by the load cell 15 via the vibrator 13, the upper part of the shaft 52 is applied with a load from the load device 11 via the vibrator 12, and preload is applied. The

  In the spindle manufacturing method using such a spindle manufacturing apparatus 10, the first signal detected by the shaft vibration sensor 16 attached to the end surface of the upper pressing member 20 in the press-fitting jig 14, and the housing of the spindle 50. The second signal detected by the housing vibration sensor 17 attached to the end face of 55 is input to the vibration detector 18 and their phases are compared. At this time, any known method may be used for the phase comparison, and the zero crossing interval of two sine waves with respect to the period of the sine wave can be simply evaluated. What is important is the fact that the frequency of the sine wave when the phase of the second signal is exactly 90 degrees behind the first signal is the correct resonant frequency. This is true even when the resonance Q value is not high. In addition, since a constant sine wave is vibrated constantly, driving is performed with a larger power compared to the conventional one, and thus a signal with a high S / N ratio is processed. That is, highly accurate detection is possible.

  When the phase difference data provided from the vibration detecting means 18 reaches a phase difference of 90 degrees, a resonance detection signal is sent to the control device 19, and the control device 19 stops the press-fitting operation and moves back in the reverse direction. The load device 11 is controlled.

  In this way, vibrations at the excitation frequency of both masses (in this case, the inner ring 52 and the outer ring 54) facing each other through the bearing rigidity can be detected, and the resonance state can be detected from the phase difference therebetween. There is no problem of detecting a resonant frequency having an error due to the fact that it is based on the transfer characteristics of the entire device included in both devices.

As shown in FIG. 2, it can be seen that it is effective to correctly grasp the transfer characteristic from X to Y in order to know the accurate bearing rigidity K. The excitation frequency is
f = (1 / 2π) √ (K / M)
Is set equal to the resonance frequency f obtained by substituting the known mass M and the predetermined rigidity K to be set. It is also possible to use a numerical analysis method such as a finite element method to obtain a relationship between the bearing stiffness and the natural frequency in advance to create a relationship and use the relationship.

When press-fitting, a load corresponding to the pressure input acts on the shaft 53 to slightly change the preload, and the rigidity and the resonance frequency are slightly shifted from the values at the time of no load, causing an error. There is a case. In this case, more accurate rigidity can be set in the excitation frequency by correcting the axial load. Using the press-fit load value F that is known in advance, the correction is made as follows.
f ′ = C (F) × f
Here, f ′ is a resonance frequency at the time of press-fitting, f is a predetermined resonance frequency, and C (F) is a correction coefficient.

  In a situation where the pressure input varies greatly depending on the spindle, the load value F may be measured by the load cell 15 at the start of press-fitting for each spindle to correct the excitation frequency. Furthermore, in order to automate this correction work, it is not difficult to create a program for a control device that controls the excitation frequency using a variable frequency oscillator.

  As shown in FIG. 3, the amplitude characteristic at the time of press-fitting is 25 dB at the peak of the resonance frequency f, and has a transfer characteristic from −10 dB to 20 dB at a portion other than the peak.

  As shown in FIG. 4, the phase characteristics during press-fitting greatly change in the range of 0 to −90 degrees and in the vicinity of −90 degrees between −90 degrees and −180 degrees.

  As shown in FIG. 5A, when press-fitting is started, there is a relationship of clearance> 0, and there is a bearing clearance.

  As shown in FIG. 5B, when the inner ring 52 slides with respect to the shaft 53 due to the press-fitting and the gap disappears, a resonance peak appears in the vicinity of 3000 Hz in the amplitude characteristics, and the relation of gap ≦ 0 is established.

  As shown in FIG. 5C, as the press-fitting proceeds, the peak frequency rises to around 8000 Hz and the height increases. At this time, since the resonance frequency f corresponding to the predetermined stiffness K is still higher than the peak frequency, the phase is on the negative side of −90 degrees.

  As shown in FIG. 5D, when the press-fitting further proceeds and the peak frequency reaches f near 9000 Hz, the phase becomes −90 degrees at f. When this phase difference reaches 90 degrees, the press-fit is completed by reaching the finishing frequency.

  As described above, in the press-fitting process, the resonance frequency shift state occurs, and it can be seen that the above-described phase difference between the two signals may be monitored by exciting with a sine wave having a frequency corresponding to the predetermined stiffness K. Actually, since the amplitude of the signal is weak at the beginning of the press-fitting, the phase detection may be inaccurate. Therefore, it is preferable to evaluate the phase after the amplitude of the signal is increased.

  According to the spindle manufacturing method using the spindle manufacturing apparatus 10 described above, the vibration detector 18 mainly detects the generation of a single sine wave and the phase difference between the first and second signals. Therefore, it can be manufactured at a low cost with a simple circuit configuration. In addition, it is possible to easily maintain reliability and improve reliability, and even when the resonance frequency is high, continuous precise detection can be performed to set the preload.

  Further, according to the spindle manufacturing method using the spindle manufacturing apparatus 10, in order to give the spindle 50 a predetermined rigidity, the phase difference is 90 degrees by applying vibration using only the corresponding sine wave of the resonance frequency. Therefore, a predetermined rigidity can be set by setting an accurate resonance frequency with a high S / N ratio even at a high frequency.

  Further, according to the spindle manufacturing method using the spindle manufacturing apparatus 10, by using the vibrators 12 and 13 that give vibration in the axial direction, an axial sine wave vibration is applied to the spindle 50 to detect vibration. By detecting the sinusoidal vibration in the axial direction by the device 18, the rigidity of the spindle 50 can be set by the sinusoidal vibration in the axial direction.

  Further, according to the spindle manufacturing method using the spindle manufacturing apparatus 10, by using the vibrators 12 and 13 that apply radial vibration, radial sine wave vibration is applied to the spindle 50 to detect vibration. By detecting the radial sinusoidal vibration by the device 18, the rigidity of the spindle 50 can be set by the radial sinusoidal vibration.

  In addition, according to the spindle manufacturing apparatus 10, the vibration detector 18 is mainly used to generate a single sine wave and to detect the phase difference between the two signals of the first and second signals. Therefore, it can be made inexpensive with a simple circuit configuration. Further, maintenance of reliability and improvement of reliability can be easily realized, and even when the resonance frequency is high, continuous accurate detection can be performed and set.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. For example, various rolling bearings such as a ball bearing, a tapered roller bearing, and a cylindrical roller bearing can be applied to the bearing used for the spindle.

  Further, the detection of the sine wave vibration is not limited to the upper pressing member of the press-fitting jig and the housing of the spindle, and may be any of the shaft or inner ring and the housing or outer ring.

1 is an overall configuration diagram of a spindle manufacturing apparatus in which an embodiment of a spindle manufacturing method and a manufacturing apparatus according to the present invention is used. It is a vibration model explanatory drawing of the spindle at the time of press fit. It is an amplitude characteristic figure at the time of press fit. It is a phase characteristic figure at the time of press fit. (A), (b), (c), (d) is a transfer characteristic diagram for explaining the transition of the resonance frequency in the press-fitting process.

Explanation of symbols

10 Spindle manufacturing equipment 11 Loading equipment (loading means)
12, 13 Exciter (excitation means)
14 Press-fitting jig (fixing means)
16 axis vibration sensor (vibration detection means)
17 Housing vibration sensor (vibration detection means)
19 Control device (control means)
50 Spindle 51 Bearing 52 Inner ring 53 Shaft 54 Outer ring 55 Housing

Claims (5)

A load means for applying a preload by relatively moving a shaft press-fitted into an inner ring of a bearing included in the spindle, an excitation means for applying vibration to the spindle, and a fixing for fixing the spindle Means, vibration detection means for detecting vibration of at least one of the housing or the outer ring of the shaft or the inner ring and the outer ring of the bearing, and control means for controlling the load means and the vibration means. A method of manufacturing a spindle using
The control means generates a sine wave having a resonance frequency corresponding to a predetermined rigidity of the spindle to drive the excitation means, and detects the phase of the sine wave of the vibration signal detected by the vibration detection means. And a preload is set by controlling the load means based on the phase value.   When the phase difference between the sine wave vibration of the shaft or the inner ring detected by the vibration detection means and the sine wave vibration of the housing or the outer ring reaches 90 degrees, the control means press-fits the inner ring The spindle manufacturing method according to claim 1, wherein the load means is controlled to stop the load and remove the load.   The exciting means applies an axial sine wave vibration to the spindle, and the vibration detecting means detects at least one axial sine wave vibration of the shaft or the inner ring and the housing or the outer ring. 3. The method for manufacturing a spindle according to claim 1, wherein the spindle is manufactured.   The excitation means applies a radial sine wave to the spindle, and the vibration detection means detects at least one radial sine wave vibration of the shaft or the inner ring and the housing or the outer ring. The method for manufacturing a spindle according to claim 1 or 2, wherein:   5. A spindle manufacturing apparatus using the spindle manufacturing method according to claim 1.

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