JP2007004917A - Dynamic vibration absorber and optical disk apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dynamic vibration absorber in which vibration absorbing efficiency is not reduced. <P>SOLUTION: The dynamic vibration absorber 10 is attached to a main chassis 18 supporting a motor driving an optical disk through an attachment pin 20. The dynamic vibration absorber 10 includes a cylindrical elastic object sub-dumper 11 having a through hole 16 inserting the attachment pin 20 and a dynamic vibration absorbing piece 17 held by the sub-dumper 11. The sub-dumper 11 is provided so as to cross an abutting part 12a abutting to a head part of the attachment pin 20, an abutting part 12b abutting to the main chassis 18, and a virtual band (a) extended so that both of the first and the second abutting parts 12a, 12b are passed in the axis direction, and has annular grooves 13a, 13b in which compression force generated between the first and the second abutting parts 12a, 12b is eliminated. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a dynamic vibration absorber and an optical disk device using the same, and more particularly to a dynamic vibration absorber whose resonance frequency does not change and an optical disk device using the same.

  An optical disk device for driving an optical medium such as a CD, CD-ROM, DVD, DVD-ROM or the like, a magneto-optical disk, a large capacity FD or the like is disclosed in, for example, Japanese Patent Laid-Open No. 2001-256762 (Patent Document 1) and Japanese Patent Laid-Open No. 2001. -355670 (Patent Document 2). FIG. 5 is a perspective view showing a main part of the optical disk device disclosed in Patent Documents 1 and 2, and FIG. 6 is a cross-sectional view of a portion indicated by VI-VI in FIG.

With reference to FIGS. 5 and 6, the optical disc apparatus 110 includes a casing 111, a main damper 112 provided at four locations around the casing 111, and a main chassis 108 held by the main damper 112. On the main chassis 108, a spindle motor 114 for rotating the optical disc 109, a head 115 for reading the optical disc 109, and a sub damper 101 are provided. A dynamic damper 107 is held in the sub damper 101. Here, the dynamic vibration absorber 107 and the sub-damper 101 constitute the dynamic vibration absorber 100.
Japanese Patent Laid-Open No. 2001-256762 (FIG. 1 and related description) Japanese Patent Laid-Open No. 2001-355670 (FIG. 3 and related descriptions)

  FIG. 7 is an enlarged view of a portion indicated by VII in FIG. Referring to FIG. 7, the sub-damper 101 constituting the dynamic vibration absorber 100 has a cylindrical shape, and the head 103 a of the mounting pin 103 attached to the main chassis 108 and the main chassis 108 are convex surfaces that are end faces of the cylinder. The parts 102a and 102b are held. A pin holding portion 104 that abuts on the mounting pin 103 is provided at the center of the inner periphery of the sub-damper 101. In addition, a recess 105 for holding the dynamic vibration absorber 107 is provided at the center of the outer peripheral portion.

  Originally, the dynamic vibration absorber 100 is designed so as to suppress a predetermined vibration. Therefore, when the sub damper 101 is mounted on the main chassis 108 by the mounting pin 103, the sub damper 101 needs to be mounted with the designed dimensions. is there. However, since the length of the mounting pin 103 is not necessarily constant, the amount of compression for compressing the sub-damper 101 varies depending on the length of the mounting pin 103 when the length of the mounting pin 103 changes. That is, when the length of the mounting pin 103 is shortened, a reaction force as indicated by an arrow A in FIG. 7 is generated in the sub damper 101, and a compressive force is applied to the pin holding portion 104. At the same time, the reaction force of the sub damper 101 pushing the mounting pin 103 changes according to the compression force, so that the frictional force on the surface of the pin holding portion 104 of the sub damper 101 and the mounting pin 103 changes. As a result, the lateral rigidity of the inner diameter portion of the sub-damper 101 such as the pin holding portion 104 and the recess 105 is changed. As a result, the resonance frequency of the dynamic vibration absorber 100 is deviated with respect to the drive rotational speed of the optical disk device, and the vibration absorption efficiency of the dynamic vibration absorber 100 is reduced.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a dynamic vibration absorber in which the vibration absorption efficiency does not decrease and an optical disk device using the same.

    The dynamic vibration absorber according to the present invention is attached to a main chassis that supports a motor for driving an optical disk via an attachment pin. The dynamic vibration absorber includes a cylindrical elastic body having a through-hole through which the mounting pin is inserted, and a dynamic vibration absorber held by the elastic body. The mounting pin is provided at one end of the shaft and the shaft. And a head having a wide surface. The elastic body includes a mounting pin holding portion that holds the shaft of the mounting pin, a first contact portion that contacts the head of the mounting pin, a second contact portion that contacts the main chassis, and first and second contacts. Pressure relief for releasing the compressive force generated between the first and second abutting portions provided in the mounting pin holding portion so as to cross at least a part of the imaginary belt extending so as to pass through both of the contact portions in the axial direction. And having a region.

  The elastic body crosses at least a part of the imaginary belt extending so as to pass through both the first contact portion contacting the head of the mounting pin and the second contact portion contacting the main chassis in the axial direction. Therefore, the compression force generated between the first and second contact portions does not affect the elastic body, and the resonance frequency at the time of design does not change.

  As a result, it is possible to provide a dynamic vibration absorber that does not reduce vibration absorption efficiency.

  Preferably, the pressure relief region does not cause stress on the mounting pin holding portion at the boundary between the mounting pin holding portion and the non-contact portion between the mounting pins.

  More preferably, the pressure relief area is a recess provided on a surface of the elastic body facing the shaft of the mounting pin.

  According to one embodiment of the present invention, the surface facing the shaft of the mounting pin between the concave portion of the elastic body and the first contact portion or the second contact portion has a space between the mounting pin.

  The recess may be an annular groove, and a plurality of the annular grooves may be provided at intervals in the axial direction of the mounting pin. A member softer than the elastic body may be inserted into the recess.

  More preferably, the pressure relief region may include portions having different strengths provided in the axial direction of the mounting pin of the elastic body, or may block pressure transmission in the axial direction.

  In another aspect of the present invention, an optical disc uses the above-described dynamic vibration absorber.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing a state in which a sub-damper (elastic body) constituting a dynamic vibration absorber of an optical disk apparatus according to the present invention is held on a main chassis with a mounting pin, and corresponds to FIG.

  With reference to FIG. 1, in the dynamic vibration absorber 10 according to this embodiment, the shaft 22 of the mounting pin 20 passes through the inner periphery of the cylindrical sub-damper 11, and the sub-damper 11 is attached to the main chassis 18. . A mounting pin holding portion 14 that abuts against the shaft 22 of the mounting pin 20 is formed at the center of the inner periphery of the sub-damper 11. The dynamic vibration absorber 17 is held in a recess 15 provided at the center of the outer periphery of the sub damper 11. Further, the contact portion 12 a provided at the upper end portion of the sub damper 11 contacts the lower end portion 21 a of the head 21 of the mounting pin 20, and the contact portion 12 b provided at the lower end portion of the sub damper 11 is the upper surface of the main chassis 18. 18a abuts. These points are the same as in FIG.

  In this embodiment, what is different from the prior art is that concave portions such as annular grooves 13 a and 13 b are provided in the upper and lower portions of the mounting pin holding portion 14 in the inner peripheral portion of the sub damper 11.

  Here, the annular grooves 13a and 13b are abutting portions 12a (first abutting portions) that abut on the heads 21 of the mounting pins of the sub damper 11 and a abutting portions 12b (first abutting portions) that abut on the main chassis 18 of the sub damper 11. 2 abutting portions) are provided so as to cross a virtual band (a portion in FIG. 1) extending so as to pass through both the first and second abutting portions in the axial direction of the mounting pin 20. Here, the annular grooves 13a and 13b cross the entire virtual band, but the present invention is not limited to this, and it is sufficient to cross at least a part of the virtual band.

  Even if the annular grooves 13a and 13b formed in the mounting pin holding portion 14 in this way have the axial dimension of the mounting pin 20 shorter than the designed dimension, the sub-damper 11 is compressed in the axial direction. , Acting as a pressure relief area to release the force. That is, no compression force is applied to the mounting pin holding portion 14 by the annular grooves 13a and 13b, and the sub-damper 11 holds the shaft 22 of the mounting pin 20 by the mounting pin holding portion 14 with the designed force, and the concave portion 15 holds the dynamic vibration absorber 17 with the designed force.

  Here, as an example of the pressure relief region, the annular groove provided in the inner peripheral portion of the contact portion has been described as an example. However, the present invention is not limited to this, and the first contact that contacts the head portion 21 of the mounting pin is described. At least a virtual band a extending so as to pass through both the contact portion 12a, the second contact portion 12b that contacts the main chassis 18, and the first and second contact portions 12a and 12b in the axial direction of the mounting pin 20. Any shape may be used as long as it is provided so as to cross and the compression force generated between the first and second contact portions can be released. Here, two annular grooves 13 are provided above and below the sub-damper 11, but this is not a limitation, and only one of them may be provided.

  Furthermore, the groove does not need to be provided continuously, and may be provided intermittently or may be a cavity. Moreover, if it exists in the inner peripheral part of a contact part, you may extend in the outer peripheral part.

  Further, the surface facing the shaft 22 of the mounting pin 20 between the annular grooves 13a and 13b and the first and second contact portions 12a and 12b has a space between the mounting pin 20 and the surface. This is not necessary.

  Next, the operation of the above-described pressure relief region will be described. 2 was created by CAE (Computer Aided Engineering) showing the state of stress generation in the dynamic vibration absorber in one embodiment of the present invention shown in FIG. 1 and the dynamic vibration absorber in the conventional example shown in FIG. FIG. Here, in each case, it is a figure which shows the stress at the time of attaching 0.2 mm with the attachment pin 20, and attaching. FIG. 2A shows the case of the present invention, and FIG. 2B shows a conventional example. Here, for easy understanding, the dynamic vibration absorber is shown rotated by 90 degrees.

  First, referring to FIG. 2B, according to the conventional example, in the convex portions 102a and 102b of the sub-damper 101, there is a portion 25 where high stress is applied, and the pin holding in the central portion of the sub-damper 101 is held. At both ends of the portion 104, there are portions 26 where low stress is applied. That is, the strength of the pin holding portion 104 that comes into contact with the mounting pin is different from the initial strength due to external stress.

  On the other hand, referring to FIG. 2 (A), according to the dynamic vibration absorber according to the embodiment of the present invention, the contact portions 12a and 12b of the sub-damper 11 are as high as FIG. 2 (B). Although the stressed portion 25 exists, the low-stressed portion 26 is only the back portion of the annular grooves 13a and 13b. No stress is applied to the boundary between the pin holding portion 14 that contacts the mounting pin at the center of the sub-damper 11 and the annular grooves 13a and 13b, that is, the non-contact portion with the mounting pin. Therefore, the sub-damper 11 can exhibit a predetermined design capability.

  Next, the effect of the present invention will be described. FIG. 3 is a diagram for explaining a difference in effect between the conventional example shown in FIG. 7 and the embodiment of the present invention shown in FIG. FIG. 3 (A) is a diagram showing the relationship between the frequency and the resonance magnification when the dynamic vibration absorber is attached to a normal length mounting pin in the dynamic vibration absorber of the present invention, and FIG. It is a figure which shows the relationship with the resonance magnification with the frequency at the time of length increasing 0.1 mm in the dynamic vibration damper of invention. 3 (C) and 3 (D) are diagrams corresponding to FIGS. 3 (A) and 3 (B) in a conventional dynamic vibration absorber.

  3 (C) and 3 (D), in the conventional dynamic vibration absorber, when the mounting length by the mounting pin is increased by 0.1 mm, the resonance frequency f0 is increased from 181.10 Hz to 173.60 Hz. It has changed. The change rate of the resonance frequency is (181.10-173.60) /181.10=0.041, which is about 4.1%. On the other hand, according to the dynamic vibration absorber of the present invention, the resonance frequency f0 is changed from 190.10 Hz to 189.12 Hz when the attachment length by the attachment pin is increased by 0.1 mm. The rate of change of the resonance frequency is (190.10-189.12) /190.10=0.005, which is about 0.5%. That is, according to the present invention, the change rate of the resonance frequency is reduced to about 1/10 compared to the conventional example.

  Next, another embodiment of the present invention will be described. FIG. 4 (A) is a diagram showing another embodiment of the dynamic vibration absorber according to the present invention. Referring to FIG. 4A, in this dynamic vibration absorber 30, the shaft 22 of the mounting pin 20 passes through the inner periphery of the cylindrical sub-damper 31, and the sub-damper 31 is moved as in the previous embodiment. It is attached to the main chassis 38. Mounting pin holding portions 34a and 34b that are divided into upper and lower inner circumferences of the sub-damper 31 and abut against the shaft 22 of the mounting pin are formed, and a recess 36 is provided therebetween. The dynamic vibration absorber 37 is held in a recess 35 provided at the center of the outer periphery of the sub damper 31. Further, the contact portion 32 a (first contact portion) provided at the upper end portion of the sub damper 31 contacts the lower end portion 21 a of the head 21 of the mounting pin 20, and the contact portion provided at the lower end portion of the sub damper 31. 32 b (second contact portion) contacts the upper surface 38 a of the main chassis 38.

  Also in this embodiment, annular grooves 33 a and 33 b are provided in the mounting pin holding portions 34 a and 34 b that hold the mounting pin 20 in the inner peripheral portion of the sub-damper 31.

  The annular grooves 33a and 33b are provided so that both the abutting portions 32a and 32b of the sub-damper 31 that abut against the head 21 and the main chassis 38 of the mounting pin 20 and the abutting portions 32a and 32b are arranged in the axial direction of the mounting pin 20. Any shape may be adopted as long as it is provided so as to cross at least a part of the virtual band a extending so as to pass through and the compression force generated between the contact portions can be released.

  Here, two annular grooves 33 are provided above and below the sub-damper 31, but the present invention is not limited to this, and only one of them may be provided. 4B, in addition to the annular grooves 33a and 33b, the shaft 22 of the mounting pin 20 between the annular grooves 33a and 33b and the first and second contact portions 32a and 32b. If spaces 39a and 39b are provided between the shaft 22 and the surface facing the surface, a greater effect can be obtained.

  As shown in FIG. 4C, there may be a case where the annular groove shown in FIG. 4A is not provided but only the recess 36 that does not contact the shaft 22 of the mounting pin 20 is provided. However, in this case, the recess 36 is not provided in the mounting pin holding portion that holds the mounting pin 20 as shown in FIG. Therefore, such a recess 36 does not correspond to the pressure relief region here.

  4B and 4C, the same portions as those in FIG. 4A are denoted by the same reference numerals, and are different from those in FIG. ) And a reference numeral obtained by adding 100 to the reference numeral shown in FIG.

  In the above embodiment, a pressure relief region such as an annular groove is provided in a region other than the mounting pin holding portion. However, the present invention is not limited to this, and the pressure relief region such as an annular groove is softer than the sub-damper. A member may be inserted.

  Further, the pressure relief region may be a portion having a different strength provided in the axial direction of the mounting pin of the sub-damper. That is, the pressure relief area may be an area that blocks the pressure transmission in the axial direction of the mounting pin.

  Although one embodiment of the present invention has been described with reference to the drawings, the present invention is not limited to the illustrated embodiment. Various modifications can be made to the illustrated embodiment within the same scope or equivalent scope as the present invention.

  Since the dynamic vibration absorber according to the present invention does not decrease the vibration absorption efficiency, it can be advantageously used in an optical disk device or the like using the vibration absorber.

It is sectional drawing of the dynamic vibration damper which concerns on one embodiment of this invention. It is a figure which shows the generation | occurrence | production state of the stress of a dynamic vibration absorber at the time of comparing this invention with a prior art example. It is a figure for demonstrating the effect of the dynamic vibration damper which concerns on this invention. It is a figure which shows the dynamic vibration damper which concerns on other embodiment of this invention. It is a perspective view which shows the principal part of an optical disk device. In FIG. 5, it is sectional drawing of the part shown by VI-VI. It is sectional drawing which shows the conventional single dynamic vibration absorber.

Explanation of symbols

  10, 30 Dynamic vibration absorber, 11, 31 Sub damper, 12, 32 Contact part, 13, 33 Groove, 14, 34 Mounting pin holding part, 15, 35 recess, 16 Through hole, 17, 37 Dynamic vibration absorber, 18, 38 Main chassis, 20 mounting pins, 21 heads, 22 axes.

Claims (10)

A dynamic vibration absorber attached to a main chassis supporting a motor for driving an optical disc via an attachment pin;
The dynamic vibration absorber includes a cylindrical elastic body having a through-hole through which the mounting pin is inserted, and a dynamic vibration absorber held by the elastic body,
The mounting pin has a shaft and a head portion provided at one end of the shaft and having a surface wider than the shaft;
The elastic body is
A mounting pin holding portion for holding the shaft of the mounting pin;
A first contact portion that contacts the head of the mounting pin;
A second contact portion that contacts the main chassis;
The mounting pin holding portion is provided so as to cross at least a part of an imaginary belt extending so as to pass through both the first and second contact portions in the axial direction, and between the first and second contact portions. A dynamic vibration absorber having a pressure relief area for releasing the compression force generated in the pressure absorber. 2. The dynamic vibration absorber according to claim 1, wherein the pressure relief region does not cause stress to the attachment pin holding portion at a boundary between the attachment pin holding portion and a non-contact portion between the attachment pins. 3. The dynamic vibration absorber according to claim 1, wherein the pressure relief region is a recess provided on a surface of the elastic body that faces the shaft of the mounting pin. The surface facing the axis of the mounting pin between the concave portion of the elastic body and the first contact portion or the second contact portion has a space between the mounting pin and the mounting pin. Dynamic vibration absorber. The dynamic vibration absorber according to claim 3 or 4, wherein the concave portion is an annular groove. 6. The dynamic vibration absorber according to claim 5, wherein a plurality of the annular grooves are provided at intervals in the axial direction of the mounting pin. The dynamic vibration absorber according to any one of claims 3 to 6, wherein a member softer than the elastic body is inserted into the concave portion. The dynamic vibration absorber according to claim 1, wherein the pressure relief region includes a portion having a different strength provided in an axial direction of the mounting pin of the elastic body. The dynamic vibration absorber according to claim 1, wherein the pressure relief region blocks transmission of pressure in the axial direction. An optical disk device using the dynamic vibration absorber according to claim 1.

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