JP5038264B2 - Dynamic damper - Google Patents

Description

  The present invention relates to a dynamic damper having a function to prevent mass metal fittings from falling off.

  Conventionally, dynamic dampers having a function of preventing mass metal fittings are disclosed in, for example, Japanese Patent Application Laid-Open No. 9-166178 (Patent Document 1) and Japanese Patent Application Laid-Open No. 10-184781 (Patent Document 2).

  Patent Document 1 includes a connecting rod that is inserted through a through-hole of an attachment member, and a pair of mass brackets that are attached to both ends of the coupling rod, and that dynamically couples both mass brackets and the attachment member with a rubber elastic body. A damper is described.

In Patent Document 2, a mass metal fitting that is spaced apart from one surface of an attachment member, a rubber elastic body that elastically connects the attachment member and the mass metal fitting, and a front end portion that is inserted from the opposite surface of the attachment member to the mass. A dynamic damper is described that includes a pin embedded in a covering member of a metal fitting.
JP-A-9-166178 Japanese Patent Laid-Open No. 10-184781

  However, since the dynamic damper described in Patent Document 1 elastically connects the pair of mass metal fittings and the mounting member with a rubber elastic body, it leads to an increase in size and a manufacturing cost. On the other hand, the dynamic damper described in Patent Document 2 includes a mass metal fitting only on one side of the mounting member, and can be reduced in size and cost. However, in the dynamic damper, when vibration is generated in the attachment member, the mass metal fitting moves in the direction of the vibration while being swung with respect to the attachment member. That is, the mass bracket performs a swing motion with respect to the mounting member.

  Here, when the mounting space for the dynamic damper is narrow, there is a risk of contact with other members due to the swinging motion of the mass bracket with respect to the mounting member. For this reason, it is desired that the mass bracket is designed to translate (straightly move) with respect to the mounting member without causing the mass bracket to swing with respect to the mounting member. However, as described above, the dynamic damper described in Patent Document 2 swings, that is, swings.

  By the way, in the dynamic damper described in Patent Document 1, it is conceivable to connect the rubber elastic body only to the mounting member and the mass bracket on one side. Certainly, this makes it possible to reduce the manufacturing cost as described above. However, even in this case, the mass bracket swings with respect to the mounting member.

  The present invention has been made in view of such circumstances, and has a configuration in which a rubber elastic body is provided only on one side of the mounting member, and the mass bracket is moved in translation with respect to the mounting member. An object of the present invention is to provide a dynamic damper having a prevention function.

  Hereinafter, each means suitable for solving the above-described problems will be described with additional effects and the like as necessary.

(Means 1) The dynamic damper according to means 1 is
A mounting member;
Trout metal fittings,
A rubber elastic body that elastically connects the mounting member and the mass bracket;
In a dynamic damper comprising
The mounting member includes a first surface fixed to the rubber elastic body, a second surface located on the back surface of the first surface, and a through hole penetrating the first surface and the second surface. ,
The mass bracket is
A first mass that is spaced apart from the first surface of the mounting member, is fixed to the rubber elastic body, cannot pass through the through-hole, and can be locked to the first surface. Metal fittings,
A second member that is spaced apart from the second surface of the mounting member, cannot pass through the through-hole, is formed to be engageable with the second surface, and is not directly connected to the mounting member. Trout metal fittings,
A connecting member that is inserted through the through-hole and connects the first mass fitting and the second mass fitting;
With
The center of gravity of the mass metal fitting is set to be located in a region surrounded by the outer surface of the rubber elastic body.

  According to this means, since each of the first mass bracket and the second mass bracket is configured to be unable to pass through the through hole, it exhibits a function of preventing the mass bracket from being detached from the mounting member. Furthermore, according to this means, it is the structure which provided the rubber elastic body only in the 1st surface side of the attachment member, Comprising: It can suppress that a mass metal fitting swings with respect to an attachment member.

(Means 2) In the dynamic damper of means 1,
The rubber elastic body has a cylindrical shape, and is fixed to a peripheral edge portion of the through hole in the first surface.
The connecting member may be inserted through a cylindrical inside of the rubber elastic body and the through hole.
Thereby, space saving can be achieved and manufacturing cost can be reduced.

(Means 3) In the dynamic damper of means 2,
The connecting member may be disposed with a gap between the entire inner peripheral surface of the rubber elastic body.
Thereby, when a mass metal fitting vibrates in the direction orthogonal to the axial center of a through-hole with respect to an attachment member, it can avoid that a connection member carries out compression deformation with respect to a rubber elastic body. That is, in the case of the vibration, the rubber elastic body has only shear deformation. Thereby, the high damping effect as a dynamic damper can be exhibited.

(Means 4) In any one of the dynamic dampers of means 1 to 3,
The distance between the center of gravity of the second mass bracket and the second surface of the mounting member may be set shorter than the distance between the center of gravity of the first mass bracket and the first surface of the mounting member. .
Thereby, the amount by which the second mass bracket protrudes from the second surface of the mounting member can be suppressed. That is, downsizing can be achieved.

(Means 5) In the dynamic damper of means 4,
The mass of the second mass bracket may be set to be different from the mass of the first mass bracket.
Thereby, the structure of the means 4 can be achieved reliably.

(Means 6) In the dynamic damper of any one of means 1 to 5,
The center of gravity of the mass metal fitting is set to coincide with the elastic center of the rubber elastic body.
Thereby, it is possible to reliably suppress the mass fitting from swinging with respect to the mounting member. In other words, the mass bracket can be surely translated with respect to the mounting member.

  Hereinafter, an embodiment embodying a dynamic damper of the present invention will be described with reference to FIGS. FIG. 1 is a front view of the dynamic damper 1. FIG. 2 is a right side view of the dynamic damper 1 of FIG. FIG. 3 is a plan view of the dynamic damper 1 of FIG. 4 is a cross-sectional view taken along line AA in FIG.

  The dynamic damper 1 includes an attachment member 10, a mass metal fitting 20, a rubber elastic body 30, and a covering rubber 40. The attachment member 10 is made of a metal such as iron or aluminum, and is attached to a counterpart member (not shown) that is desired to suppress vibration. The mass metal fitting 20 is made of metal such as iron or aluminum, and is spaced apart from the mounting member 10. The rubber elastic body 30 elastically connects the mounting member 10 and the mass metal fitting 20. Details will be described below. First, the positional relationship of each member when the counterpart member is not vibrating will be described.

  The mounting member 10 includes a mounting seat 11, a standing portion 12, and flange portions 13 and 14. The mounting seat 11 has a flat plate shape and is formed with two bolt holes 11a and 11b. The mounting seat 11 is attached to the mating member by a bolt (not shown) inserted through the bolt holes 11a and 11b while being in contact with the mating member.

  The standing portion 12 is a flat plate member that is erected almost vertically from the edge of the mounting seat 11. The standing portion 12 is formed in a substantially rectangular shape. Furthermore, a rectangular through hole 12 c that penetrates the first surface 12 a and the second surface 12 b of the standing portion 12 is formed in the center of the standing portion 12. Here, the 1st surface 12a is a side in which the mounting seat 11 in the standing part 12 is located. Moreover, the 2nd surface 12b is a surface located in the back surface of the 1st surface 12a. The flange portions 13 and 14 are formed on both side edges of the mounting seat 11 and the upright portion 12 so as to stand substantially vertically on the mounting seat 11 and the upright portion 12. These flange portions 13 and 14 have a reinforcing role for positioning the mounting seat 11 and the standing portion 12.

  The mass bracket 20 includes a first mass bracket 21, a second mass bracket 22, and a connecting member 23. The 1st mass metal fitting 21 consists of a rectangular parallelepiped metal lump. This first mass metal fitting 21 is arranged separately on the first surface 12 a side of the standing portion 12. Specifically, the predetermined surface 21 a of the first mass fitting 21 is arranged so as to face the first surface 12 a of the standing portion 12. Furthermore, the center of gravity of the first mass fitting 21 is located coaxially with the central axis of the through hole 12c. The outer shape of the first mass fitting 21 is formed larger than the through hole 12c. Therefore, the first mass bracket 21 has a size that cannot pass through the through hole 12c.

  The 2nd mass metal fitting 22 consists of a rectangular parallelepiped metal lump. The second mass metal fitting 22 is arranged separately on the second surface 12b side of the standing portion 12. That is, the standing portion 12 is interposed between the first mass bracket 21 and the second mass bracket 22. Specifically, the predetermined surface 22 a of the second mass metal fitting 22 is disposed so as to face the second surface 12 b of the standing portion 12. Furthermore, the center of gravity of the second mass fitting 22 is positioned coaxially with the central axis of the through hole 12c. The outer shape of the second mass fitting 22 is formed larger than the through hole 12c. Therefore, the second mass metal fitting 22 has a size that cannot pass through the through hole 12c. However, the second mass bracket 22 has an outer shape smaller than the outer shape of the first mass bracket 21. Since the second mass bracket 22 is made of the same material as the first mass bracket 21, the mass of the second mass bracket 22 is smaller than the mass of the first mass bracket 21.

  The connecting member 23 has a rod shape, and the cross-sectional shape in the direction perpendicular to the axis is the same rectangular shape in the axial direction. The cross-sectional shape of the connecting member 23 is smaller than the through hole 12c. Accordingly, naturally, the cross-sectional shape of the connecting member 23 is smaller than the shape of the predetermined surface 21 a of the first mass fitting 21 and the shape of the predetermined surface 22 a of the second mass fitting 22. The connecting member 23 connects the predetermined surface 21 a of the first mass fitting 21 and the predetermined surface 22 a of the second mass fitting 22. Further, the connecting member 23 is inserted through the through hole 12c. At this time, the outer peripheral surface of the connection member 23 is made not to contact the inner peripheral surface of the through hole 12c over the entire periphery. The central axis of the connecting member 23 is set so as to pass through the center of gravity of the first mass bracket 21 and the center of gravity of the second mass bracket 22. Accordingly, the central axis of the connecting member 23 is positioned so as to coincide with the central axis of the through hole 12c.

  The center of gravity G1 of the mass bracket 20 configured in this way is located closer to the first mass bracket 21 than the center of the line segment connecting the center of gravity of the first mass bracket 21 and the center of gravity of the second mass bracket 22. Yes. That is, the separation distance between the center of gravity of the second mass fitting 22 and the second surface 12b of the standing portion 12 is set shorter than the separation distance between the center of gravity of the first mass fitting 21 and the first surface 12a of the standing portion 12. ing. Furthermore, the center of gravity G1 of the mass bracket 20 as a whole is located on a line segment connecting the center of gravity of the first mass bracket 21 and the center of gravity of the second mass bracket 22.

  The rubber elastic body 30 is formed in a cylindrical shape. Specifically, the cross-sectional shape in the direction perpendicular to the axis of the outer peripheral surface of the rubber elastic body 30 is the same rectangular shape in the axial direction. The cross-sectional shape of the inner peripheral surface of the rubber elastic body 30 in the direction perpendicular to the axis also has the same rectangular shape over the axial direction. Specifically, the cross-sectional shape of the inner peripheral surface of the rubber elastic body 30 in the direction orthogonal to the axis is formed to be slightly smaller than the through hole 12 c of the standing portion 12. Further, the cross-sectional shape of the inner peripheral surface of the rubber elastic body 30 in the direction perpendicular to the axis is smaller than the outer shape of the connecting member 23.

  The cylindrical one end surface of the rubber elastic body 30 is fixed to the peripheral edge portion of the through hole 12c in the first surface 12a of the standing portion 12. The other cylindrical end surface of the rubber elastic body 30 is fixed to a predetermined surface 21 a of the first mass fitting 21. That is, the rubber elastic body 30 elastically connects the standing portion 12 and the predetermined surface 21 a of the first mass fitting 21.

  Further, the connecting member 23 is inserted through the cylindrical inside of the rubber elastic body 30 so that the connecting member 23 does not contact the inner peripheral surface of the rubber elastic body 30. That is, there is a gap over the entire circumference between the inner peripheral surface of the rubber elastic body 30 and the outer peripheral surface of the connecting member 23. The central axis of the inner peripheral surface of the rubber elastic body 30 is set so as to coincide with the central axis of the through hole 12 c of the standing portion 12 and the central axis of the connecting member 23. The elastic center G2 of the rubber elastic body 30 is the center of the left and right end faces of FIG. 1 showing the front view, the center of the upper and lower end faces of FIG. 2 showing the right side view, and the center of the left and right end faces of FIG. To position.

  The covering rubber 40 covers the inner peripheral surface of the through hole 12 c of the standing portion 12. The covering rubber 40 is set so as to have a gap with the outer peripheral surface of the connecting member 23 over the entire inner peripheral surface.

  As described above, the first mass fitting 21 is elastically connected to the standing portion 12 by the rubber elastic body 30. On the other hand, the second mass bracket 22 is not directly connected to the standing portion 12, and only indirectly with the standing portion 12 via the connecting member 23, the first mass bracket 21 and the rubber elastic body 30. It is connected. That is, the rubber elastic body 30 is provided only on the first surface 12 a side of the standing portion 12, and is not provided on the second surface 12 b side of the standing portion 12. As described above, by using only one side of the rubber elastic body 30 standing portion 12, molding can be facilitated and the manufacturing cost can be reduced.

  The center of gravity G1 of the mass bracket 20 as a whole is set so as to be located in a region surrounded by the outer surface of the rubber elastic body 30 (each flat surface including both end surfaces in the axial direction and the outer peripheral surface). In the present embodiment, the center of gravity G1 of the mass fitting 20 as a whole is set to coincide with the elastic center G2 of the rubber elastic body 30.

  Accordingly, when the mating member vibrates in the vertical direction or the front-rear direction of FIG. Here, since the center of gravity G1 of the entire mass metal fitting 20 and the elastic center G2 of the rubber elastic body 30 coincide, the moving direction of the entire mass metal fitting 20 with respect to the mounting member 10 coincides with the excitation direction. That is, the mass metal fitting 20 does not swing (swing motion) with respect to the mounting member 10 and translates.

  In order to explain this in more detail, the following experiment was conducted. First, acceleration sensors were attached to the first mass fitting 21 and the second mass fitting 22, and the attachment member 10 was vibrated at various vibration frequencies in the vertical direction of FIG. For comparison, a similar experiment was performed on the dynamic damper 100 of the comparative example shown in FIG. The dynamic damper 100 of the comparative example shown in FIG. 5 differs from the dynamic damper 1 of the present embodiment in the following points. The first difference is that the second mass fitting 122 has the same size and mass as the first mass fitting 21. The second difference is that the distance between the center of gravity of the second mass metal fitting 122 and the second surface 12b of the upright portion 12 is the distance between the center of gravity of the first mass metal fitting 21 and the first surface 12a of the upright portion 12. This is the same point as the separation distance. A third difference is that the axial length of the connecting member 123 is longer than that of the connecting member 23 in accordance with the above difference. Therefore, the center of gravity G1 of the mass fitting 120 is different from the elastic center G2 of the rubber elastic body 30. Furthermore, the center of gravity G1 of the mass fitting 120 is located outside the region surrounded by the outer surface of the rubber elastic body 30.

  The experimental results are shown in FIGS. FIG. 6 is a diagram illustrating frequency characteristics of vibrations of the first mass bracket 21 and the second mass bracket 22 for the dynamic damper 1 of the present embodiment. FIG. 7 is a diagram illustrating frequency characteristics of vibrations of the first mass fitting 21 and the second mass fitting 122 for the dynamic damper 100 of the comparative example. 6 and FIG. 7, the broken line indicates the frequency characteristic of the vibration of the first mass fitting 21, and the solid line indicates the frequency characteristic of the vibration of the second mass fitting 22.

  As shown in FIG. 6, in the dynamic damper 1 of the present embodiment, the first mass fitting 21 and the second mass fitting 22 have approximate frequency characteristics. From this, it can be said that the first mass fitting 21 and the second mass fitting 22 perform substantially the same operation at each vibration frequency of the mounting member 10. That is, the first mass bracket 21 and the second mass bracket 22 are almost in translation.

  In contrast, as shown in FIG. 7, in the dynamic damper 100 of the comparative example, the first mass fitting 21 and the second mass fitting 122 have different frequency characteristics. For example, at the vibration frequency of 40 Hz of the mounting member 10, the gain of the first mass bracket 21 is about half of the gain of the second mass bracket 122.

  Here, the greater the gain, the higher the vibration suppression effect. That is, for example, when the vibration frequency of the mounting member 10 is 40 Hz, the gain of both the mass brackets 21 and 122 of the dynamic damper 100 of the comparative example is obtained by combining the gains of both the mass brackets 21 and 22 of the dynamic damper 1 of the present embodiment. It can be seen that it is larger than the combination of. Therefore, according to the dynamic damper 1 of the present embodiment, a large vibration suppressing effect can be exhibited with respect to the vibration in the target frequency band.

  Furthermore, in the dynamic damper 100 of the comparative example, the frequency characteristic of the first mass fitting 21 has two resonance frequencies. Therefore, since the frequency band which exhibits the vibration suppression effect is dispersed, the dynamic damper 100 cannot be used when it is desired to exhibit the vibration suppression effect only in a specific frequency band. On the other hand, in the dynamic damper 1 of the present embodiment, since the resonance frequencies of the first mass fitting 21 and the second mass fitting 22 are substantially the same, it is possible to exert a vibration suppressing effect only in a specific frequency band. You can be sure.

  Moreover, the dynamic damper 1 of this embodiment has the following effects. A first mass fitting 21 and a second mass fitting 22 that cannot pass through the through hole 12c of the standing portion 12 are provided at both ends of the connecting member 23. From this, the first mass bracket 21 can be locked to the first surface 12 a of the standing portion 12, and the second mass bracket 22 can be locked to the second surface 12 b of the standing portion 12. That is, the mass metal fitting 20 as a whole exhibits a function of preventing the falling from the standing portion 12.

  Further, the rubber elastic body 30 has a cylindrical shape and is fixed to the peripheral edge portion of the through hole 12 c in the first surface 12 a of the standing portion 12. In such a configuration, the connecting member is inserted through the cylindrical inside of the rubber elastic body 30 and the through hole 12c of the standing portion 12 together. Thereby, space saving can be achieved and manufacturing cost can be reduced.

  Further, the connecting member 23 is arranged with a gap between the entire inner peripheral surface of the rubber elastic body 30. Thereby, when the mass metal fitting 20 vibrates in the direction orthogonal to the central axis of the through hole 12a of the standing portion 12 with respect to the standing portion 12, the connecting member 23 is compressed and deformed with respect to the rubber elastic body 30. Can be avoided. That is, in the case of the vibration, the rubber elastic body 30 is only subjected to shear deformation. Thereby, the high damping effect as a dynamic damper can be exhibited.

  Furthermore, the separation distance between the center of gravity of the second mass fitting 22 and the second surface 12b of the standing portion 12 is set shorter than the separation distance between the center of gravity of the first mass fitting 21 and the first surface 12a of the standing portion 12. ing. Thereby, the amount which the 2nd mass metal fitting 21 protrudes from the 2nd surface 12b of the standing part 12 can be suppressed. That is, downsizing can be achieved. Furthermore, the first mass bracket 21 is located on the side where the mounting seat 11 is located when the upright portion 12 is used as a reference. Thereby, even when it sees as the dynamic damper 1 whole, the amount which protrudes in the 2nd surface 12b side of the standing part 12 on the basis of the standing part 12 can be suppressed. That is, it contributes to downsizing of the dynamic damper 1 as a whole.

  Further, the covering rubber 40 covers the inner peripheral surface of the through hole 12 c of the standing portion 12. That is, the covering rubber 40 can prevent the generation of abnormal noise and vibration due to the direct contact between the through hole 12c of the standing portion 12 and the connecting member 23.

  In the dynamic damper 1 of the above-described embodiment, the center of gravity G1 of the mass fitting 20 as a whole is made to coincide with the elastic center G2 of the rubber elastic body 30. This is the best way to achieve the above effect. Even if the center of gravity G1 and the elastic center G2 are slightly shifted, the above effect can be sufficiently exhibited. However, it is necessary that the center of gravity G1 is located in a region surrounded by the outer surface of the rubber elastic body 30.

  Further, the connecting member 23 is inserted through not only the through hole 12 c of the standing portion 12 but also the cylindrical interior of the rubber elastic body 30. In addition, the connection member 23 may be configured not to pass through the cylindrical inside of the rubber elastic body 30. In this case, the rubber elastic body 30 is not cylindrical and can have a shape having no space inside. However, as described above, when the connecting member 23 is inserted through the through hole 12c of the standing portion 12 and the cylindrical inside of the rubber elastic body 30, space saving and manufacturing cost reduction can be achieved.

1 is a front view of a dynamic damper 1. FIG. It is a right view of the dynamic damper 1 of FIG. It is a top view of the dynamic damper 1 of FIG. It is AA sectional drawing of FIG. It is sectional drawing of the dynamic damper 100 of a comparative example. It is a frequency characteristic which shows the experimental result about the dynamic damper 1 of this embodiment. It is a frequency characteristic which shows the experimental result about the dynamic damper 100 of a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,100: Dynamic damper 10: Mounting member 11: Mounting seat, 11a, 11b: Bolt hole 12: Standing part, 12a: First surface, 12b: Second surface, 12c: Through-hole 13, 14: Flange part 20 : Mass bracket,
21: 1st mass metal fitting, 22, 122: 2nd mass metal fitting, 23: Connecting member 30: Rubber elastic body, 40: Cover rubber G1: Center of gravity of mass metal fitting 20, G2: Elastic center of rubber elastic body 30

Claims (6)

A mounting member;
Trout metal fittings,
A rubber elastic body that elastically connects the mounting member and the mass bracket;
In a dynamic damper comprising
The mounting member includes a first surface fixed to the rubber elastic body, a second surface located on the back surface of the first surface, and a through hole penetrating the first surface and the second surface. ,
The mass bracket is
A first mass that is spaced apart from the first surface of the mounting member, is fixed to the rubber elastic body, cannot pass through the through-hole, and can be locked to the first surface. Metal fittings,
A second member that is spaced apart from the second surface of the mounting member, cannot pass through the through-hole, is formed to be engageable with the second surface, and is not directly connected to the mounting member. Trout metal fittings,
A connecting member that is inserted through the through-hole and connects the first mass fitting and the second mass fitting;
With
The dynamic damper, wherein the center of gravity of the mass metal fitting is set to be located in a region surrounded by the outer surface of the rubber elastic body. The rubber elastic body has a cylindrical shape, and is fixed to a peripheral edge portion of the through hole in the first surface.
The dynamic damper according to claim 1, wherein the connecting member is inserted through a cylindrical inside of the rubber elastic body and the through hole.   The dynamic damper according to claim 2, wherein the connecting member is disposed with a gap between the connecting member and the entire inner peripheral surface of the rubber elastic body.   The separation distance between the center of gravity of the second mass bracket and the second surface of the mounting member is set shorter than the separation distance between the center of gravity of the first mass bracket and the first surface of the mounting member. The dynamic damper as described in any one of 1-3.   The dynamic damper according to claim 4, wherein a mass of the second mass bracket is set to be different from a mass of the first mass bracket.   The dynamic damper according to any one of claims 1 to 5, wherein a center of gravity of the mass metal fitting is set to coincide with an elastic center of the rubber elastic body.

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