JP2007321884A - Vibration reducing member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration reducing member capable of obtaining a sufficient vibration reducing effect by adjusting the natural frequency of vibrating parts according to the excitation frequency of a vibrating apparatus without changing lengths of the vibrating parts. <P>SOLUTION: The vibration reducing member 1 has a body 10 into which the vibrating apparatus is fixedly disposed. Slits of peninsula shapes are formed at the body 10. Inner sides of the slits are made to be vibrating parts 21, 22, and through holes 21z, 22z are formed at tips of the vibrating parts 21, 22. Inertial masses of the vibrating parts are thus reduced to set the natural frequency high without changing the lengths of the vibrating parts. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vibration reducing member that reduces vibration caused by a vibration device.

  AV and OA devices such as DVDs (Digital Versatile Discs) and printers use components that rotate at high speed, such as motors, gears, and HDDs (Hard Disk Drives). In recent years, these motors and gears have been rotated at higher speeds to achieve higher speeds and higher functions of AV and OA equipment. This has led to an increase in noise generated from equipment. For this reason, it is desired to reduce the vibration generated by a motor rotating at high speed and the noise caused by the vibration. Patent Document 1 discloses a dynamic vibration absorber that reduces such vibration. The dynamic vibration absorber of Patent Document 1 is configured such that a weight and a viscoelastic body are integrally formed and attached to a rotating shaft of a motor, whereby the dynamic vibration absorber itself vibrates to reduce the vibration of the motor.

JP 2002-266940 A

  In the case where the cause of the vibration is a resonance caused by vibration of the vibration device in each part such as a bracket, a frame, and an exterior panel to which the vibration device such as a motor and a gear is fixed, Patent Document 1 By attaching a dynamic vibration absorber (a dynamic vibration absorber with attenuation) using a viscoelastic body such as that adjusted to the natural frequency in each region, vibration at that region can be reduced. However, when the cause of vibration is forced vibration (vibration of the vibration device itself) caused by the vibration device, even if the natural frequency of the dynamic vibration absorber is adjusted to the vibration frequency of the vibration device, it is generated in the viscoelastic body. The phase of displacement and force do not match, and the vibration suppression force of the dynamic vibration absorber and the forced excitation force of the vibration device are not completely in opposite phases. Therefore, the displacement of the dynamic vibration absorber mounting point does not become zero, and a sufficient vibration reduction effect cannot be obtained.

  In view of this, it is considered that by providing a dynamic vibration absorber (undamped dynamic vibration absorber) integrally formed with the structure to which the vibration device is fixed, forced vibration by the vibration device can be reduced. In this configuration, if the natural vibration frequency of the dynamic vibration absorber and the excitation frequency of the vibration device are matched by changing the length and thickness of the vibrating part (vibration part) in the dynamic vibration absorber, the vibration device A vibration suppression force having a phase opposite to that of the forced excitation force due to the vibration of the vibration is generated in the dynamic vibration absorber, and a sufficient vibration reduction effect is obtained.

  Using this configuration, when adjusting the natural frequency of a dynamic vibration absorber to correspond to different types of vibration equipment, there is a large gap between surrounding members under the installation conditions of the structure. There is no problem when the vibration part of the vibration absorber can be lengthened. However, depending on the installation conditions of the structure, it may be difficult to change the length of the vibration part. In this case, even if the above dynamic vibration absorber is used, the natural frequency and vibration of the dynamic vibration absorber The vibration frequency by the device cannot be matched, and a sufficient vibration reduction effect cannot be obtained.

  Accordingly, an object of the present invention is to provide a vibration reduction member that can adjust the natural frequency of the vibration part in accordance with the excitation frequency of the vibration device without changing the length of the vibration part, and can obtain a sufficient vibration reduction effect. Is to provide.

Means and effects for solving the problems

  In order to achieve the above object, the vibration reducing member of the present invention is a plate-like structure in which a vibration device is fixedly arranged, and a peninsula-shaped cut is made in the plate-like structure, and an inner portion of the cut And a through hole is formed in the vibration part. According to this, by reducing the inertial mass of the vibration part, the natural frequency can be set high without changing the length of the vibration part. Therefore, even if the length of the vibration part is not changed, the natural frequency of the vibration part can be adjusted according to the excitation frequency by the vibration device, and a sufficient vibration reduction effect can be obtained.

  Further, in another aspect, the vibration reducing member of the present invention is a plate-like structure in which a vibration device is fixedly arranged, and a peninsula-shaped notch is made in the plate-like structure, and the thickness of the vibration part is increased. It is thinner than other parts locally. According to this, by reducing the inertial mass of the vibration part, the natural frequency can be set high without changing the length of the vibration part. Therefore, even if the length of the vibration part is not changed, the natural frequency of the vibration part can be adjusted according to the excitation frequency by the vibration device, and a sufficient vibration reduction effect can be obtained.

  In another aspect, the vibration reducing member of the present invention is a plate-like structure on which a vibration device is fixedly arranged, and a peninsula-shaped cut is made in the plate-like structure, and an inner portion of the cut is vibrated. The width of the tip of the vibrating part is different from the width of the connecting part. According to this, the natural frequency can be arbitrarily set by changing the inertial mass and the spring constant of the vibration part. Therefore, even if the length of the vibration part is not changed, the natural frequency of the vibration part can be adjusted according to the excitation frequency by the vibration device, and a sufficient vibration reduction effect can be obtained.

  In another aspect, the vibration reducing member of the present invention is a plate-like structure on which a vibration device is fixedly arranged, and a peninsula-shaped cut is made in the plate-like structure, and an inner portion of the cut is vibrated. And a recess is formed in the vibration part. According to this, the natural frequency can be set high by increasing the bending rigidity of the vibration part. Therefore, even if the length of the vibration part is not changed, the natural frequency of the vibration part can be adjusted according to the excitation frequency by the vibration device, and a sufficient vibration reduction effect can be obtained.

  Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings.

  First, the vibration reducing member according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic cross-sectional view of the vibration reducing member according to the present embodiment as viewed from above, and shows the overall configuration of the present embodiment. FIG. 2 is a perspective view showing the structure of the vibration reducing member of FIG.

  As shown in FIG. 1, the vibration reducing member 1 has a main body portion 10. The main body 10 is a plate-like structure formed by bending a single steel plate into a U-shape, and has a back surface 10a and side surfaces 10b and 10b. For example, vibration devices such as a motor 6 and a gear 7 used for an OA (Office Automation) device, an AV (Audio Visual) device, and the like are fixedly arranged in the main body unit 10. In the present embodiment, the motor 6 has a rotating shaft 6a and a gear 6b attached to the tip of the rotating shaft 6a. The gear 7 is provided so as to mesh with the gear 6b of the motor 6. The gear 7 rotates when the gear 6b rotates, and transmits the driving force of the motor 6 to another device (not shown). Note that the vibration device is not limited to a rotation mechanism that rotates at a constant rotation speed such as a motor or a gear, but also includes a vibration mechanism that is excited by an electric signal having a constant frequency, such as an electromagnetic coil used in a speaker. All vibration sources that generate vibration at a constant frequency are applicable.

  Further, shaft holes 10h and 10i are formed in the main body 10, and the rotating shaft 6a of the motor 6 and the rotating shaft 7a of the gear 7 are rotatably supported in the shaft hole 10h and the shaft hole 10i. Thereby, the motor 6 and the gear 7 are fixedly disposed on the main body 10. Hereinafter, the motor 6 and the gear 7 are referred to as vibration devices. In FIG. 2, the motor 6, the gear 7, and the shaft holes 10h and 10i are omitted.

  As shown in FIG. 2, the main body 10 has a vibration pair 20. The vibration pair 20 is formed by cutting the back surface 10a, and is for reducing vibration in a direction perpendicular to the back surface 10a of the main body 10 due to driving of the vibration device.

  Next, the configuration of the vibration pair 20 will be described with reference to FIGS. 2 and 3. FIG. 3 is a front enlarged schematic view of the vibration pair 20 of FIG. As shown in FIG. 2, a vibration pair 20 is formed on the back surface 10 a of the main body 10. As shown in FIG. 3, the vibration pair 20 has two vibration parts 21 and 22, and these two vibration parts 21 and 22 are penetrated in the thickness direction of the steel plate from the back surface 10 a, respectively, and have the same shape. The two U-shaped cuts 21s and 22s are formed. Furthermore, the through-holes 21z and 22z are formed in the front-end | tip parts in the vibration parts 21 and 22, respectively. In addition, the two vibrating portions 21 and 22 are connected to the connecting portions 21c and 22c that connect the inner portions 21i and 22i of the two U-shaped cuts 21s and 22s and the main body portion 10 to each other, and to the back surface 10a. The vertical planes are formed so as to be symmetrical with each other. By configuring the vibration pair 20 in this way, the vibration units 21 and 22 can vibrate in the normal direction of the back surface 10a, that is, in the same direction as the vibration direction by the vibration device.

  When the natural frequencies of the vibration parts 21 and 22 of the vibration pair 20 match the vibration frequency of the vibration device, the vibration parts 21 and 22 vibrate without the main body part 10 vibrating, and the main body part 10 Vibration can be minimized. Therefore, the shape dimensions (specifically, the longitudinal length, width, and thickness of the inner portions 21i and 22i) of the vibration pair 20 are appropriately adjusted so that these frequencies coincide with each other. ing.

Here, the adjustment of the frequency of the vibration pair 20 will be described with reference to FIGS. FIG. 6D is a schematic diagram illustrating a state in which the vibration unit 21 is oscillating, and FIG. 6E is a schematic diagram illustrating a structure of a leaf spring when the vibration unit 21 is assumed to be a leaf spring. is there. Since the vibration of the main body 10 is generated by the rotation of the motor 6 that is a vibration device and the engagement of the gears 6b and 7, the vibration frequency Ω of the main body 10 is equal to the excitation frequency Ω _O caused by the forced vibration of the vibration device. , the relationship Ω = Ω _O is established. In addition, since the frequency Ω _O by the vibration device is known, the frequency Ω of the main body 10 is also determined thereby. Further, the vibrating portions 21 and 22 that vibrate are considered as leaf springs having a weight at the tip (see FIGS. 6D and 6E), the spring constant is k, the mass of the vibrating portions 21 and 22 is m, and the vibration is When the natural frequency of the parts 21 and 22 is ω, the following relationship is established.
k = mω ² (Formula 1)
Furthermore, as described above, if the following equation is satisfied, the vibration of the main body 10 can be minimized.
ω = Ω (Formula 2)
From the above, the vibration pair 20 is formed by changing m and k by appropriately adjusting the shape and size of the vibration parts 21 and 22 so as to satisfy both the expressions (1) and (2). The vibration of the main body 10 can be minimized.

  Next, the adjustment of the frequency of the vibration pair 20 using the vibration unit 21 will be described more specifically. A schematic cross-sectional view taken along the line AA of the vibration part 21 shown in FIG. 4 is shown in FIG. 6D in a vibrating state, and such a vibration part has a weight at the tip as described above. It can be considered to be replaced with a leaf spring model with (see FIG. 6E). Considering such a leaf spring, if the spring constant of the spring portion is k and the effective inertia mass of the weight at the time of vibration is m, the relationship of Equation 1 above is established. Here, the vibration of the main body 10 can be minimized by changing k and m so as to satisfy the above formula 2.

  In the present embodiment, by forming the through holes 21z and 22z at the tips of the vibrating parts 21 and 22, the inertial mass of the vibrating part 21 is reduced, so that the length of the vibrating parts 21 and 22 is not changed. The natural frequency can be set high. By doing so, the natural frequency ω of the vibrating parts 21 and 22 can be appropriately adjusted according to the excitation frequency by the vibrating device without changing the length of the vibrating parts 21 and 22, and sufficient vibration can be achieved. A reduction effect is obtained.

  Here, for example, if there is a vibrating portion 21A having a length L as shown in FIG. 4, this is a standard vibrating portion. Here, the vibration part 21B has a length L ', and L' is longer than the length L of the vibration part 21A. By doing in this way, the natural frequency of the vibration part 21B can be made low. Further, the natural frequency can be set higher than that of the vibration unit 21 by making the length L ″ shorter than L as in the vibration unit 21C. However, it may be difficult to change the length of the vibration part in the main body part depending on the installation conditions and the installation environment of the main body part. For example, this is a case where the length L is longer than the main body. In such a case, the length of the vibrating portion can be designed to be short like the vibrating portion 21C with respect to the vibrating portion 21A, but it may be difficult to make it long like the vibrating portion 21B. Conceivable. Therefore, by forming the through-hole 21y near the root (connecting portion) of the vibrating portion 21E as in the vibrating portion 21E shown in FIG. 5, the spring constant k of the vibrating portion 21E is reduced, and the length of the vibrating portion 21E is increased. The natural frequency ω can be set low without changing the length. Therefore, it is possible to appropriately adjust the natural frequency ω of the vibration unit according to the excitation frequency of the vibration device without changing the length of the vibration unit.

  Moreover, in this embodiment, since the vibration parts 21 and 22 are formed in plane symmetry in the back surface 10a, these two vibration parts 21 and 22 connect the connection parts 21c and 22c of the two vibration parts 21 and 22. It is designed to vibrate to the base point. If the shapes of the vibrating portions 21 and 22 are not plane-symmetric, a torsional moment is generated at the central portion 23 with the vibration of the vibrating portions 21 and 22. As a result, when the shape and size of the main body 10 are changed, the natural frequencies of the vibration portions 21 and 22 are also changed, and the natural frequencies of the vibration portions 21 and 22 are changed only by the shape and dimensions of the vibration portions 21 and 22. Cannot be set. However, since the vibrating portions 21 and 22 are formed in plane symmetry as in the present embodiment, a torsional moment is not generated in the central portion 23 due to the vibration of the vibrating portions 21 and 22. Therefore, the natural frequency of the vibrating parts 21 and 22 can be set only by the shape and size of the vibrating parts 21 and 22.

  Further, as described above, since the vibration parts 21 and 22 constituting the vibration pair 20 are formed by cutting the steel plate forming the main body part 10, vibration attenuation by the vibration device in the vibration parts 21 and 22 is achieved. Can be made substantially zero. Specifically, vibration due to friction caused by dislocation within the material of the vibration reducing member 1 or vibration due to friction with air is converted into thermal energy. 21 and 22 are integrally formed, the contact friction between the main body 10 and the vibration parts 21 and 22 is eliminated, and only the friction inside the material and the air friction are generated. Can be approached. As a result, the displacement and the force generated in the vibration units 21 and 22 vibrate in the same phase, so that a forced excitation force due to the vibration of the vibration device and a vibration suppression force in the opposite phase are generated. As described above, since the vibration pair 20 functions as a dynamic vibration absorber without attenuation, the displacement at the connecting portions 21c and 22c that connect the vibration pair 20 and the main body portion 10 can be always zero, and the cause of vibration Even when is a forced vibration of the vibration device, a sufficient vibration reduction effect can be obtained.

  Further, the vibration parts 21 and 22 constituting the vibration pair 20 are integrally formed on the same steel plate as the steel plate forming the main body part 10. Therefore, the main body portion 10 and the vibration portions 21 and 22 of the vibration reducing member 1 can be manufactured in the same manufacturing process, so that a separate material for forming the vibration portion is unnecessary, and the manufacturing time of the vibration portion is shortened. can do.

  The damping characteristic of the vibrating vibration pair 20 is preferably tan δ = 0.05 or less, where δ is the phase of displacement and force generated in the vibration pair 20. In addition to the steel plate described above, the material for forming the main body 10 is preferably an elastic material with less attenuation, such as a metal such as a stainless steel plate, an aluminum plate, or a copper plate, or an engineering plastic. Between the vibration parts 21 and 22 can be as close to zero as possible.

(First to thirteenth modifications)
Next, first to ninth modified examples of the present embodiment will be described with reference to FIGS. 4 to 6 focusing on portions different from the above-described embodiment. 4 to 6 show only a modification of one of the vibration pairs having two vibration parts (vibration part 21) and omit the other vibration part, but the other vibration is similar to the above embodiment. It is assumed that the part is formed in plane symmetry. If it is difficult to change the length of the vibration part due to the installation environment and installation conditions of the main body, the natural frequency ω of the vibration part can be set under the restriction by making the vibration part as follows. It becomes possible to set appropriately.

  Hereinafter, the modifications described in FIGS. 4 and 6 will be described. The vibration part is not limited to those formed by a U-shaped cut as in the above embodiment, and the width of the tip of the vibration part is the same as in the first to sixth modifications described below. It may be different from the width of the connecting portion. In the vibration part 21F according to the first modification, the vibration part 21G according to the second modification, and the vibration part 21H according to the third modification, the tip of the vibration part is wider than the base connection part. By doing in this way, the inertial mass of the vibration parts 21F-21H increases, and a natural frequency can be set low. Therefore, even if the length of the vibration part is not changed, the natural frequency of the vibration part can be adjusted according to the excitation frequency by the vibration device, and a sufficient vibration reduction effect can be obtained. Conversely, like the vibrating portions 21P to 21R according to the fourth to sixth modifications, the tip of the vibrating portion may be narrower than the base connecting portion. By doing in this way, the spring constant k of the vibration parts 21P-21R increases, and the natural frequency can be set high. Therefore, even if the length of the vibration part is not changed, the natural frequency of the vibration part can be adjusted according to the excitation frequency by the vibration device, and a sufficient vibration reduction effect can be obtained.

  Next, the modification described in FIGS. 5 and 6 will be described. In FIGS. 5 and 6, (a), (b), and (c) are shown for each modified example, with (a) being a top view and (b) and (c) being (a). The AA cross section and BB cross section corresponding to are shown. In the vibrating part 21I according to the seventh modification, a concave part 21x is formed by locally denting the main body part by pressing or the like. By doing so, the bending rigidity at the tip of the vibration part 21I increases, and the natural frequency can be adjusted high without changing the length of the vibration part 21I.

This adjustment will be described with reference to the model shown in FIG. By providing the recess 21x, the tip portion functions as a weight (mass m) instead of a leaf spring, and the length of the leaf spring portion (portion other than the recess) is reduced. Here, as in Equation 3 below, the mass m of the weight increases in proportion to the first power of the length of the concave portion, and the spring constant k increases in inverse proportion to the third power of the length of the portion other than the concave portion. Therefore, when the length of the leaf spring portion decreases, the spring constant k increases. From Equation 2, the relationship of ω = √ (k / m) is established, and ω increases as k increases. In this way, the natural frequency of the vibration part can be adjusted.
m Ｌ Lα, k ∝ 1 / {(1-α) L} ³ (Formula 3)

As for the vibration part 21J which concerns on an 8th modification, the recessed part 21w is long formed in the longitudinal direction of the vibration part. As a result, the length of the portion functioning as the weight of the tip portion is increased, and the length of the leaf spring portion is further reduced, so that the spring constant k is further increased (Equation 3) and the natural frequency is higher than that of the vibrating portion 21I. Can be set high. Moreover, by doing in this way, the part corresponded to a weight increases and an inertial mass becomes large. As described above, the natural frequency ω can be adjusted by appropriately setting the length L of the vibrating portion and the ratio α of the concave portion (see Formula 4).
ω = √ (k / m) ∝√ [1 / (αL) · 1 / {(1-α) L} ³ ]
= √ (1 / {α (1-α) ³ · L ⁴ })
ω √ √ (1 / {α (1-α) ³ · L ⁴ }) (Formula 4)
(0 <α <1)
α: Ratio of the length of the concave portion to the length L of the vibrating portion (αL: length of the concave portion)

  Further, the length of the concave portion 21v is increased in a direction perpendicular to the longitudinal direction as in the vibrating portion 21K according to the ninth modification, and further, the concave portion 21u is formed as in the vibrating portion 21L according to the tenth modified example. By elongating the length in the longitudinal direction, the natural frequency can be appropriately set by changing the spring constant k.

  Further, in the vibration part 21M according to the eleventh modification, the length of the concave part 21r is made longer than that of the vibration part 21J. By doing in this way, the cross-sectional secondary moment of a BB cross section increases, and the spring constant k becomes large, Therefore A natural frequency can be made high.

  In the vibration part 21N according to the twelfth modification, a plurality of recesses 21q are formed on the surface of the vibration part 21N, and by doing so, the natural frequency of the vibration part 21N can be similarly adjusted. By doing as described above, the natural frequency of the vibration part can be adjusted in accordance with the excitation frequency by the vibration device without changing the length of the vibration part, and a sufficient vibration reduction effect can be obtained.

  Further, in the vibrating portion 21O according to the thirteenth modification, the plate thickness of the tip 21o is made thinner than other portions. By doing so, the inertial mass of the vibration part 21O is reduced as in the case where the through hole is formed at the tip of the vibration part, so that the natural frequency is set high without changing the length of the vibration part 21O. it can. Therefore, even if the length of the vibration part is not changed, the natural frequency of the vibration part can be adjusted according to the excitation frequency by the vibration device, and a sufficient vibration reduction effect can be obtained.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims.

  For example, in the above-described embodiment, the main body is described as fixing the motor 6 and the gear 7 used in the OA device or the like, but may be used to fix other devices. Further, the shape of the main body portion may be a shape other than the U-shape, and may have an upper portion and a bottom portion.

  Further, if the area of the vibration part is large, it becomes a noise source. Therefore, it is desirable to make the width of the vibration part 1/100 or less as compared with the wavelength at the natural frequency of the vibration part.

  In the above embodiment, the vibration pair is composed of two vibration parts. However, even if there is only one vibration part, the vibration of the main body part can be reduced.

The cross-sectional schematic diagram in the top view of the vibration reduction member which concerns on one Embodiment of this invention. The perspective view of the vibration reduction member of FIG. FIG. 3 is an enlarged schematic view of the vibration pair of FIG. 2 in a front view. The perspective view which shows the 1st thru | or 6th modification of the vibration reduction member which concerns on one Embodiment of this invention. The perspective view which shows the 7th thru | or 10th modification of the vibration reduction member which concerns on one Embodiment of this invention. The perspective view which shows the 11th and 13th modification of the vibration reduction member which concerns on one Embodiment of this invention.

Explanation of symbols

1 Vibration reduction member 6 Motor (vibration equipment)
7 Gears (vibration equipment)
DESCRIPTION OF SYMBOLS 10 Main body part 20 Vibrating pair 21, 21A-21C, 21E-21R, 22 Vibrating part 21q, 21r, 21u, 21v, 21w, 21x Recessed part 21y, 21z, 22z Through-hole 21c, 22c Connection part 21i, 22i Inner part of cut 21s, 22s notch 23 center

Claims (4)

A plate-like structure on which the vibration device is fixedly arranged,
A peninsula-shaped cut is made in the plate-like structure, and the inner part of the cut is a vibration part.
A vibration reducing member, wherein a through hole is formed in the vibration part. A plate-like structure on which the vibration device is fixedly arranged,
A peninsula-shaped cut is made in the plate-like structure, and the inner part of the cut is a vibration part.
A vibration reducing member characterized in that a plate thickness of the vibration part is locally thinner than other parts. A plate-like structure on which the vibration device is fixedly arranged,
A peninsula-shaped cut is made in the plate-like structure, and the inner part of the cut is a vibration part.
A vibration reducing member, wherein a width of a tip of the vibration part is different from a width of a connection part. A plate-like structure on which the vibration device is fixedly arranged,
A peninsula-shaped cut is made in the plate-like structure, and the inner part of the cut is a vibration part.
A vibration reducing member, wherein a concave portion is formed in the vibration portion.

Images