JP2024020813A - soundproofing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve soundproofing performance of a soundproofing device without increasing mass of the soundproofing device.

SOLUTION: A soundproofing cap 1 comprises a cover body 10 that is a member formed from rubber-like elastic material, and a sound absorbing body 20 that is a member formed from porous material. The cover body 10 comprises a front surface 11 and a back surface 12, and an outer edge 13. The sound absorbing body 20 is attached to the back surface 12 of the cover body 10. The sound absorbing body 20 has a plurality of protruding portions 30 which are portions protruding toward the back side. Each of the plurality of protruding portions 30 forms a space 40 open to the back side between adjacent other protruding portions 30.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a soundproofing device, and more particularly to a soundproofing device that is attached to a vibrating member to prevent sounds emitted by the member.

2. Description of the Related Art Conventionally, soundproofing devices have been known that are attached to a vibrating member to reduce the sound emitted by the member. Such a soundproofing device includes, for example, a soundproofing cap used in a torsional damper. A torsional damper is a component that is attached to the tip of the crankshaft of the engine of a vehicle or general-purpose machine to reduce torsional vibration of the crankshaft. The torsional damper may resonate in the axial direction of the crankshaft in response to vibrations of the crankshaft. When the torsional damper resonates, sound radiates forward from the torsional damper. This is thought to be because the air around the torsional damper is pushed out by the vibrations of the hub and the vibration ring, causing pressure fluctuations around the torsional damper.

In order to reduce the radiated sound from such a torsional damper, a soundproof cap is attached to the torsional damper. Some soundproof caps attached to torsional dampers are made of rubber and are attached to the outer peripheral end of a hub of a torsional damper so as to cover the hub (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 2003-216160

Conventional soundproof caps for torsional dampers are required to further improve the effect of reducing sound radiated from the torsional damper. Regarding the improvement of the effect of reducing the radiated sound, the sound insulation performance of the radiated sound from the torsional damper can be improved by increasing the mass of the soundproof cap based on the mass law. However, as the mass of the soundproof cap increases, the weight increases, the resonance frequency of the soundproof cap decreases, and the soundproof cap may resonate due to the vibration of the torsional damper. When a heavy soundproof cap resonates, a large amount of energy is given to the air around the soundproof cap, and the air around the soundproof cap is pushed out with a large amount of energy. For this reason, when a heavy soundproof cap vibrates in the resonant frequency region, the soundproofing effect of the soundproof cap may be reduced.

For this reason, there is a need for a conventional soundproof cap for a torsional damper to have a configuration that can improve the soundproofing performance of the soundproof cap without increasing the mass of the soundproof cap.

An object of the present invention is to provide a soundproofing device that can improve the soundproofing performance of the soundproofing device without increasing the mass of the soundproofing device.

In order to solve the above problems, a soundproofing device according to the present invention is made of a rubber-like elastic material and includes a pair of surfaces and an outer peripheral end portion that extends annularly on the outer peripheral side of the pair of surfaces. A cover body is a member, and a sound absorber is a member made of a porous material and is attached to one of the pair of surfaces of the cover body, and the sound absorber is a member of the cover body. It has a plurality of protrusions that protrude toward the facing side of the one surface, and each of the plurality of protrusions has a space between the other adjacent protrusions and the surface of the one surface. It is characterized by the fact that it forms an open space on the side where people use the space.

In the soundproofing device according to one aspect of the present invention, the protrusion enters the space from the side facing the one surface, and at least a part of the sound wave reflected by the protrusion is transmitted to the other protrusion. It is shaped like a.

In the soundproofing device according to one aspect of the present invention, the space becomes narrower from the side facing the one surface toward the side facing the other of the pair of surfaces.

In the soundproofing device according to one aspect of the present invention, each of the protrusions has a surface that is inclined with respect to the one surface so as to face the side facing the one surface, and the inclined surface forms the space.

In the soundproofing device according to one aspect of the present invention, each of the plurality of protrusions forms the space between the other protrusion adjacent in the direction along the one surface. .

In the soundproofing device according to one aspect of the present invention, each of the protrusions has a wedge shape that becomes thinner toward the side facing the one surface, and the protrusions are arranged along the one surface. The protrusions adjacent to each other are arranged in different directions.

In the soundproofing device according to one aspect of the present invention, the cover body can be attached to the hub of the torsional damper at the outer peripheral end so that the sound absorbing body faces the hub of the torsional damper.

According to the soundproofing device according to the present invention, the soundproofing performance of the soundproofing device can be improved without increasing the mass of the soundproofing device.

FIG. 1 is a plan view of a soundproof cap as a soundproof device according to an embodiment of the present invention. FIG. 2 is a rear view of a soundproof cap as a soundproof device according to an embodiment of the present invention. It is a perspective view of the back side of the soundproof cap as a soundproof device concerning an embodiment of the present invention. 1 is a cross-sectional view taken along the axis of a soundproof cap as a soundproof device according to an embodiment of the present invention. It is a perspective view which expands and shows one of the protrusion parts of a soundproof cap. It is a side view which expands and shows one of the protrusion parts of a soundproof cap. FIG. 3 is a front view of a torsional damper with a soundproof cap attached. FIG. 3 is a cross-sectional view taken along the axis of the torsional damper to which the soundproof cap is attached. It is a figure for explaining the effect|action of a soundproof cap.

Embodiments of the present invention will be described below with reference to the drawings.

The soundproofing device according to the present invention is attached to a vibrating member and is intended for soundproofing the sound emitted by this member. The soundproofing device according to the present invention is attached to, for example, a torsional damper attached to the end of a crankshaft of an engine of a vehicle or a general-purpose machine, and prevents sounds emitted from the torsional damper. Note that the application target of the soundproofing device according to the present invention in which the soundproofing device according to the present invention is used is not limited to torsional dampers. For example, the soundproofing device according to the present invention can be applied to things for which the effect of the soundproofing device according to the present invention is effective.

FIG. 1 is a plan view of a soundproof cap 1 as a soundproof device according to an embodiment of the present invention, FIG. 2 is a rear view of the soundproof cap 1, and FIG. 3 is a plan view of the soundproof cap 1 as seen from the back side. FIG. 4 is a cross-sectional view of the soundproof cap 1 taken along the axis x. As shown in FIGS. 1 to 4, the soundproof cap 1 includes a pair of surfaces 11 and 12, and an outer peripheral end portion 13 that extends annularly on the outer peripheral side of the pair of surfaces 11 and 12. A cover body 10 that is a member made of a material, and a sound absorber 20 that is a member made of a porous material attached to a back surface 12 that is one of the pair of surfaces 11 and 12 of the cover body 10. It is equipped with The sound absorber 20 has a plurality of protrusions 30 that protrude toward the back side, which is the side facing the back surface 12 of the cover body 10 . Each of the plurality of protrusions 30 forms a space 40, which is a space open to the back side, between adjacent protrusions 30. Note that in FIGS. 2 to 4, only part of the protrusion 30 and the space 40 are labeled with reference numerals. Hereinafter, the structure of the soundproof cap 1 will be explained in detail.

As shown in FIGS. 1 to 4, the cover body 10 is a disc-shaped member, for example, a disc-shaped or approximately disc-shaped member whose central axis or approximately central axis is the axis x. In the cover body 10, the front surface 11, which is the other of the pair of surfaces, and the back surface 12, which is one of the pair of surfaces, are opposite to each other. As described above, for convenience of explanation, the side facing the back surface 12 will be referred to as the back side, and the side facing the front surface 11 will be referred to as the front side. The front side is the side in the direction of arrow a in the axis x direction, as shown in FIG. 4, and the back side is the side in the direction of arrow b in the axis x direction, as shown in FIG. The front surface 11 and the rear surface 12 extend parallel or substantially parallel to each other, for example. Further, as shown in FIG. 4, for example, the front surface 11 is a plane or a substantially plane that is orthogonal to or substantially orthogonal to the axis x, and the back surface 12 is a plane that is orthogonal or substantially orthogonal to the axis x, as shown in FIG. Or it is substantially flat.

The outer circumferential end portion 13 forms an annular end on the outer circumferential side of the cover body 10, and for example, as shown in FIGS. It extends to The outer circumferential end portion 13 is shaped so that it can be attached to the hub of a torsional damper in order to use the soundproof cap 1, which will be described later, with the soundproof cap 1 attached to the torsional damper. For example, as shown in FIG. 4, the outer peripheral end portion 13 is tapered in a cross section along the axis x (hereinafter also simply referred to as a cross section). Further, the cover body 10 has a rising surface 14 that is an annular surface extending between the outer circumferential end (outer circumferential end 12a) of the back surface 12 and the outer circumferential end 13, as shown in FIGS. 2 to 4, for example. ing. Specifically, the rising surface 14 is a surface whose diameter decreases from the front surface 11 side toward the back surface 12 side, as shown in FIG. 4, for example.

The cover body 10 is made by molding a rubber-like elastic material into the shape described above. The thickness T1 of the cover body 10 is uniform or approximately uniform in the cover body 10. As shown in FIG. 4, the thickness T1 of the cover body 10 is the distance between the front surface 11 and the back surface 12 in the axis x direction. The thickness T1 of the cover body 10 is, for example, 3 to 5 mm. Note that the thickness T1 of the cover body 10 is not limited to 3 to 5 mm.

The sound absorber 20 has a plurality of protrusions 30 and a base portion 21, as shown in FIGS. 2 to 4, for example. The protruding portion 30 is a portion that protrudes from the base portion 21 toward the back side. The base portion 21 is a portion attached to the cover body 10.

Specifically, the base portion 21 is a disk-shaped portion, for example, as shown in FIGS. 2 to 4, and is, for example, a disk-shaped or approximately disk-shaped portion with the axis x as the central axis or approximately the central axis. , has a base surface 21a and a mounting surface 21b, which are a pair of surfaces facing away from each other. The mounting surface 21b is, for example, a surface extending parallel or substantially parallel to the back surface 12 of the cover body 10, and can be closely attached to the back surface 12 of the cover body 10. Further, the base surface 21a is, for example, a surface that extends parallel or substantially parallel to the mounting surface 21b. The base surface 21a is, for example, a plane or substantially orthogonal to the axis x, as shown in FIG. 4, and the mounting surface 21b is a plane orthogonal or substantially orthogonal to the axis x, as shown in FIG. Or it is substantially flat. Further, the base portion 21 has an outer circumferential surface 21c that is an annular surface connecting the base surface 21a and the mounting surface 21b on the outer circumferential side. The outer circumferential surface 21c is, for example, a surface that extends in a cylindrical shape or a substantially cylindrical shape with the axis x as the central axis or approximately the central axis.

For example, as shown in FIG. 4, the mounting surface 21b of the base portion 21 extends to the same or approximately the same size as the back surface 12 of the cover body 10. Further, the base surface 21a extends to the same or approximately the same size as the mounting surface 21b, as shown in FIG. 4, for example. The thickness T2 of the base portion 21 is uniform or approximately uniform in the base portion 21. As shown in FIG. 4, the thickness T2 of the base portion 21 is the distance between the base surface 21a and the mounting surface 21b in the axis x direction.

As described above, a plurality of protrusions 30 protrude from the base surface 21a of the base body 21 toward the back side, and there is a space between one protrusion 30 and another protrusion 30 adjacent to this protrusion 30. A space 40 is formed in the space. As shown in FIGS. 2 to 4, the space portions 40 communicate with other adjacent space portions 40 in the direction in which the base surface 21a extends, and all the space portions 40 are connected to one another extending between the protruding portions 30. They form a space S, which is one space. The protrusion 30 is shaped such that, for example, the protrusion 30 enters the adjacent space 40 from the back side, and at least a portion of the sound wave reflected by the protrusion 30 hits another protrusion 30 . Specifically, the space 40 becomes narrower from the back side to the front side, as shown in FIGS. 2 to 4, for example. Specifically, the space portion 40 has a shape such that the area in a cross section perpendicular to the axis x decreases from the back side toward the front side in the axis x direction.

In order for the protruding parts 30 to have a shape that acts on sound waves as described above, each of the protruding parts 30 has a surface on the back side with respect to the back surface 12 or the base surface 21a, as shown in FIGS. 2 to 4, for example. It has an inclined surface 31 which is a surface inclined so as to This inclined surface 31 forms a space 40. For example, the space 40 is formed such that the inclined surface 31 faces the inclined surface 31 of another protrusion 30 in the direction along the base surface 21a (radial direction perpendicular to the axis x). Further, for example, the space portion 40 is formed such that the inclined surface 31 faces a portion of another protrusion 30 that is not the inclined surface 31 in the direction along the base surface 21a. Furthermore, for example, each of the protrusions 30 forms a space 40 between it and another protrusion 30 adjacent to it in the direction along the back surface 12 of the cover body 10 . Specifically, for example, each of the protrusions 30 may have, in addition to the inclined surface 31, an inclined surface 32 which is a surface that is inclined similarly to the inclined surface 31. Further, each of the protrusions 30 may have other surfaces in addition to the inclined surface 31, or may have other surfaces in addition to the inclined surfaces 31 and 32. The other surface may be a surface that is not inclined with respect to the back surface 12, for example, a surface that is perpendicular to the back surface 12 or the base surface 21a, or may be a surface that is inclined with respect to the back surface 12 or the base surface 21a. It may be a plane parallel to the back surface 12 or the base surface 21a.

In the illustrated example, as shown in FIGS. 2 to 4, each of the protrusions 30 has a wedge shape that becomes thinner toward the back side, and the protrusions 30 are mutually arranged in the direction along the back surface 12. Adjacent protrusions 30 are arranged in different directions. Further, as shown in FIGS. 2 and 3, the protrusions 30 are provided on the entire or substantially the entire base surface 21a, and the plurality of protrusions 30 are provided on the outer circumferential side with an annular contour, for example, around the axis x. They are arranged so as to form an annular or annular outline.

FIG. 5 is an enlarged perspective view of one of the protrusions 30, and FIG. 6 is an enlarged side view of one of the protrusions 30. Specifically, the protrusion 30 has two inclined surfaces 31 and 32 facing away from each other, as shown in FIGS. 5 and 6, for example. The inclined surface 31 is between a root end 31a, which is an end on the root side of the inclined surface 31 connected to the base surface 21a of the base body part 21, and a tip 31b, which is an end on the back side (tip side) of the inclined surface 31. The inclined surface 31 is inclined with respect to the base surface 21a such that the tip 31b is closer to the inclined surface 32 than the root end 31a. That is, as shown in FIG. 6, the angle α between the base surface 21a and the inclined surface 31 is larger than 90° (α>90°). In this way, the inclined surface 31 is inclined so as to face the back side with respect to the base surface 21a. More specifically, the inclined surface 31 is inclined with respect to the base surface 21a so that the projection plane in the direction of the axis x is formed on the back side. Further, for example, the length of the root end 31a and the length of the tip 31b are the same or approximately the same. Further, for example, the inclined surface 31 is a flat surface or a substantially flat surface. The length of the root end 31a and the length of the tip 31b may be different. Further, the inclined surface 31 may not be a flat surface, but may be a curved surface, or may be a combination of a flat surface and a curved surface.

The inclined surface 32 has a base end 32a, which is the end on the root side of the inclined surface 32 connected to the base surface 21a of the base body part 21, and a tip 32b, which is the end on the back side (tip side) of the inclined surface 32. The inclined surface 32 is inclined with respect to the base surface 21a such that the tip 32b is closer to the inclined surface 31 than the root end 32a. That is, as shown in FIG. 6, the angle β between the base surface 21a and the inclined surface 32 is larger than 90° (β>90°). In this way, the inclined surface 32 is inclined so as to face the back side with respect to the base surface 21a. More specifically, the inclined surface 32 is inclined with respect to the base surface 21a so that the projection plane in the direction of the axis x is formed on the back side. Further, for example, the length of the root end 32a and the length of the tip 32b are the same or approximately the same. Further, for example, the inclined surface 32 is a flat surface or a substantially flat surface. The length of the root end 32a and the length of the tip 32b may be different. Further, the inclined surface 32 may not be a flat surface, but may be a curved surface, or may be a combination of a flat surface and a curved surface.

As shown in FIGS. 5 and 6, for example, the inclined surface 31 and the inclined surface 32 are symmetrical or substantially symmetrical, and the root end 31a and the root end 32a have the same length or approximately the same length. The tips 31b and 32b have the same length or substantially the same length, and the inclined surfaces 31 and 32 have the same size (area) or substantially the same size. Further, the angle α of the inclined surface 31 and the angle β of the inclined surface 32 are the same or substantially the same. Note that the inclined surface 31 and the inclined surface 32 do not have to be plane symmetrical. The shape of the inclined surface 31 and the shape of the inclined surface 32 may be different from each other. For example, the root end 31a and the root end 32a may have different lengths, the tip 31b and the tip 32b may have different lengths, and the inclined surface 31 and the inclined surface 32 may have different lengths. It may be a size (area). Furthermore, the angle α of the inclined surface 31 and the angle β of the inclined surface 32 may be different angles.

Further, as shown in FIGS. 5 and 6, the protruding portion 30 has a distal end surface 33 that is a surface extending between the distal end 31b of the inclined surface 31 and the distal end 32b of the inclined surface 32. The tip surface 33 faces the back side, and is, for example, a plane or substantially parallel to a plane orthogonal to the axis x. The tip surface 33 may be a surface inclined with respect to a plane perpendicular to the axis x. In addition, the tip surface 33 does not have to be a flat surface, but may be a curved surface, or may be a combination of a flat surface and a curved surface.

Further, as shown in FIGS. 2 to 5, the protrusion 30 has a pair of opposite side surfaces 34 and 35. As shown in FIGS. The side surface 34 has one side end (side end 31c) which is a pair of ends that are opposite to each other in the extending direction of the protruding part 30 of the inclined surface 31, and one side end (side end 31c) that is opposite to each other in the extending direction of the protruding part 30 of the tip surface 33. One side end (side end 33a) that is a pair of ends, one side end (side end 32c) that is a pair of ends that are opposite to each other in the extending direction of the protrusion 30 of the inclined surface 32, and the base surface 21a. It is a surface that spreads between. The side surface 35 includes the other of the pair of side edges of the inclined surface 31 (the side edge 31d), the other of the pair of side edges of the distal end surface 33 (the side edge 33b), and the other of the pair of side edges of the inclined surface 32 (the side edge 31d). This is a surface extending between the end 32d) and the base surface 21a. Note that the extending direction of the protruding portion 30 is a direction extending along the base surface 21a of the protruding portion 30, and is a direction in which the root end 31a and the tip 31b or the root end 32a and the tip 32b extend.

The side surfaces 34 and 35 are, for example, planes or substantially planes parallel or substantially parallel to a plane orthogonal to the base surface 21a. The side surfaces 34 and 35 may be planes or substantially planes that are inclined with respect to the base surface 21a. Furthermore, the side surfaces 34 and 35 do not have to be flat surfaces, but may be curved surfaces or surfaces made of a combination of a flat surface and a curved surface.

In the illustrated example of the protrusion 30, the inclined surfaces 31 and 32, the tip surface 33, and the side surfaces 34 and 35 are flat. Further, the inclined surface 31 and the inclined surface 32 are plane symmetrical. Further, the tip surface 33 extends parallel to a plane perpendicular to the axis x. Further, the side surfaces 34 and 35 are perpendicular to the base surface 21a. Further, in the protruding portion 30, the root end 31a of the inclined surface 31, the root end 32a of the inclined surface 32, the root end 34a of the side surface 34, and the root end 35a of the side surface 35 have the same length. Note that the root end 34a of the side surface 34 is the end of the side surface 34 that connects to the base surface 21a, and the root end 35a of the side surface 35 is the end of the side surface 35 that connects to the base surface 21a.

As shown in FIG. 2, the sound absorber 20 has a plurality of (m) protrusion groups 3Ln (n is a natural number from 1 to m) formed by a plurality of protrusions 30 lined up. The protrusion groups 3Ln are arranged in the direction along the base surface 21a, specifically, in the arrangement direction Ln (n is from 1 to m), which is a direction perpendicular to the axis x or a direction parallel to the direction perpendicular to the axis x. natural numbers). Further, in each of the protrusion group 3Ln, a plurality of protrusions 30 are arranged in the corresponding arrangement direction Ln. Further, in each of the protrusion group 3Ln, the plurality of protrusions 30 are provided so that the extending direction of each protruding part 30 is different from the extending direction of other adjacent protruding parts 30. Moreover, between the protrusion groups 3Ln-1 and 3Ln that are adjacent to each other, the protrusions 30 that are adjacent to each other in the direction perpendicular to the arrangement directions Ln-1 and Ln are provided so that their extension directions are different from each other. There is.

Specifically, for example, as shown in FIGS. 2 to 4, in each of the protrusion groups 3Ln, the plurality of protrusions 30 are such that the extending direction of each protruding part 30 is orthogonal to the extending direction of the other adjacent protruding parts 30. Or they are provided so as to be substantially orthogonal. As shown in FIG. 2, in each of the protrusion group 3Ln, the entire root ends 34a, 35a of the side surfaces 34, 35 of the protrusion 30 are connected to the base end 31a of the slope 31 of the adjacent protrusion 30 or the slope 32 of the protrusion 30. It is in contact with the entire root end 32a of. Further, as shown in FIG. 2, among the protrusion groups 3Ln-1 and 3Ln adjacent to each other, the protrusions 30 that are adjacent to each other in the direction perpendicular to the arrangement directions Ln-1 and Ln have extension directions perpendicular to each other or They are provided so as to be substantially perpendicular to each other.

In each of the protrusion groups 3Ln, the plurality of protrusions 30 may be provided such that the extension direction of the protrusions 30 changes regularly in the arrangement direction Ln, and the extension direction of the protrusions 30 in the arrangement direction Ln It may be provided so that the direction changes irregularly. Similarly, among the protrusion groups 3L1 to 3Lm, the protrusions 30 may be provided in each of the protrusion groups 3Ln so that the extending direction changes regularly in the direction perpendicular to the arrangement direction Ln. Further, among the protrusion groups 3L1 to 3Lm, the protrusions 30 may be provided in each of the protrusion groups 3Ln so that the extending direction changes irregularly in the direction perpendicular to the arrangement direction Ln.

Furthermore, in the illustrated example, the protrusions 30 are provided in alignment in the direction perpendicular to the arrangement direction Ln, but the protrusions 30 are not provided in alignment in the direction perpendicular to the arrangement direction Ln. It's okay. That is, in the illustrated example, the entire root ends 34a, 35a of the side surfaces 34, 35 of the protrusion 30 contact the entire root end 31 of the slope 31 of the adjacent projection 30 or the root end 32a of the slope 32. As shown in FIG. Protrusions 30 that are adjacent in the direction perpendicular to the arrangement direction Ln may be shifted from each other in the arrangement direction Ln so as not to contact the entire root end 31 of the inclined surface 31 or the entire root end 32a of the inclined surface 32.

The sound absorber 20 is produced by molding the porous material into the shape described above. The plurality of protruding parts 30 and the base part 21 are respective parts of the sound absorbing body 20 that are integrally formed from the same material. Porous materials for the sound absorber 20 include, for example, urethane foam, glass wool, rock wool, felt, melamine foam, and PET fiber. Note that the porous material of the sound absorber 20 is not limited to these porous materials. The sound absorber 20 is fixed to the cover body 10 with adhesive, for example. Specifically, the mounting surface 21b of the base portion 21 of the sound absorber 20 is adhesively fixed to the back surface 12 of the cover body 10. Note that the sound absorbing body 20 may be fixed to the cover body 10 by a method other than adhesion.

Next, a usage state of the soundproof cap 1 having the above-described configuration attached to the torsional damper 100 to which the soundproof cap 1 is applied will be described. FIG. 7 is a front view of the torsional damper 100 to which the soundproof cap 1 is attached, and FIG. 8 is a sectional view along the axis x1 of the torsional damper 100 to which the soundproof cap 1 is attached.

The torsional damper 100 has a conventionally known configuration, and includes a hub 110, a vibration ring 120 as a mass body, and a vibration ring 120 arranged between the hub 110 and the vibration ring 120, as shown in FIGS. A damper elastic body 130 is provided. The hub 110 is an annular member whose central axis is the axis x1, and includes a boss portion 111 on the inner circumferential side, a rim portion 112 on the outer circumferential side, and a substantially disk-shaped disk connecting the boss portion 111 and the rim portion 112. 113. The hub 110 is manufactured, for example, from a metal material by casting or the like.

The boss portion 111 of the hub 110 is a cylindrical portion whose center axis is the axis x1 in which the through hole 114 is formed, and a disk portion 113 extends from the outer circumferential surface of the boss portion 111 toward the outer circumferential side. The rim portion 112 of the hub 110 is a cylindrical portion whose central axis is the axis x1, and is a portion located concentrically with respect to the boss portion 111 on the outer peripheral side of the boss portion 111. A disk portion 113 extends toward the inner circumferential side from an inner circumferential surface 112 a that is an inner circumferential surface of the rim portion 112 . A damper elastic body 130 is crimped onto an outer peripheral surface 112b, which is a surface on the outer peripheral side of the rim portion 112. The disk portion 113 extends between the boss portion 111 and the rim portion 112 and connects the boss portion 111 and the rim portion 112.

The vibration ring 120 is a cylindrical member whose central axis is the axis x1, and has a shape that covers the outer peripheral side of the hub 110. Specifically, the inner circumferential surface 121, which is the inner circumferential surface of the vibration ring 120, has a shape that faces the outer circumferential surface 112b of the rim portion 112 of the hub 110 with a gap therebetween. Further, a plurality of annular V-grooves 123 are formed on an outer circumferential surface 122, which is a surface on the outer circumferential side of the vibration ring 120, and a timing belt (not shown) can be wound thereon. The damper elastic body 130 is damper rubber, is press-fitted between the vibration ring 120 and the rim portion 112, and is fitted and fixed between the inner peripheral surface 121 of the vibration ring 120 and the outer peripheral surface 112b of the rim portion 112. ing.

The torsional damper 100 is used by being fixed to the end of the crankshaft of an engine with bolts. In the torsional damper 100, the vibration ring 120 and the damper elastic body 130 form a damper portion, which reduces torsional vibration of the crankshaft.

A soundproof cap 1 can be attached to the torsional damper 100. The soundproof cap 1 can be attached to a position where it can prevent the sound generated when the hub 110 and the vibration ring 120 vibrate in the axis x1 direction due to vibrations transmitted from the crankshaft. Specifically, for example, as shown in FIG. 8, the torsional damper 100 is configured such that the soundproof cap 1 covers the space formed by the hub 110 on the atmosphere side, that is, the space surrounded by the rim part 112 and the disc part 113. A soundproof cap 1 can be attached. Specifically, a receiving groove 115, which is an annular groove capable of receiving the outer peripheral end 13 of the cover body 10 of the soundproof cap 1, is formed in the atmospheric side end 112c of the inner peripheral surface 112a of the rim part 112. There is. Note that the atmosphere side is the side opposite to the side that becomes the engine side.

The soundproof cap 1 is configured such that the outer peripheral end 13 of the cover body 10 can be inserted into the receiving groove 115 of the torsional damper 100, and the outer peripheral end 13 received in the receiving groove 115 can be inserted into the receiving groove. It can be removed from 115. Further, the outer circumferential end portion 13 of the cover body 10 can be engaged with the receiving groove 115 so that the soundproof cap 1 is fixed to the hub 110. Further, the soundproof cap 1 is attached to the torsional damper 100 so that the protruding portion 30 of the sound absorbing body 20 faces the disk portion 113 of the hub 110.

In the illustrated example, the receiving groove 115 is a groove extending in an annular or substantially annular shape with the axis x1 as the central axis or approximately the central axis. Further, the outer circumferential end portion 13 of the cover body 10 is shaped to be immovable in the axis x1 direction with respect to the hub 110 when received in the receiving groove 115. Further, as shown in FIGS. 7 and 8, in the torsional damper 100 in use with the soundproof cap 1 attached, the protrusion 30 of the sound absorber 20 of the soundproof cap 1 is opposed to the disc part 113 of the hub 110. There is. Further, the axis x of the soundproof cap 1 and the axis x1 of the torsional damper 100 coincide or substantially coincide.

Next, the function of the soundproof cap 1 will be explained. FIG. 9 is a schematic diagram for explaining the function of the soundproof cap 1.

When the crankshaft rotates, the torsional damper 100 emits sound waves in various traveling directions. Among these sound waves, the sound waves that enter any of the spaces 40 of the space S hit the protrusion 30 of the sound absorber 20 . A portion of the sound waves that hit the protrusion 30 are absorbed by the sound absorber 20 from the protrusion 30 . On the other hand, a portion of the sound waves that hit the protrusion 30 are reflected and return to the space 40 . As described above, the protrusion 30 is shaped such that at least a portion of the sound wave reflected by the protrusion 30 hits another protrusion 30 . Therefore, at least a portion of the sound waves reflected by the protrusion 30 and returned to the space 40 hit other protrusions 30 . Similarly, some of the sound waves that hit the protrusion 30 are absorbed by the sound absorber 20 from the protrusion 30, while some of the sound waves that hit the protrusion 30 are reflected and return to the space 40. At least a portion of the sound waves that have returned to the space 40 similarly hit other protrusions 30 and are absorbed from the protrusions 30 or reflected by the protrusions 30 . Thereafter, the same action on the sound waves is repeated.

The sound waves absorbed by the sound absorber 20 from the protrusion 30 travel inside the sound absorber 20 . When sound waves pass through the porous structure of the sound absorber 20, frictional heat is generated between the air and the fleshy parts that form the sound absorber 20, thereby attenuating the sound waves and reducing the sound. Specifically, the sound waves are absorbed from the inclined surfaces 31 and 32, the tip surface 33, and the side surfaces 34 and 35 of the protrusion 30. Further, when a gap is provided between adjacent protrusions 30 on the base surface 21a of the base portion 21, sound waves are also absorbed from the base surface 21a.

Specifically, for example, as shown in FIG. 9, among the sound waves W that entered any of the spaces 40 of the space S, at least a part of the sound waves W reflected by the inclined surface 31 or the inclined surface 32 may be reflected by the other It hits the protrusion 30. In addition, sound waves reflected from the side surface 34 or the side surface 35 may also hit other protrusions 30 . Further, depending on the shape of the distal end surface 33 and the position of the distal end surface 33 from the base surface 21a, the sound waves reflected from the distal end surface 33 may also hit other protrusions 30. Since the inclined surfaces 31 and 32 are inclined with respect to the base surface 21a as described above, the sound waves reflected from the inclined surfaces 31 and 32 are likely to hit the other protruding portions 30. In addition, if a gap is provided between adjacent protrusions 30 on the base surface 21 a of the base portion 21 , the sound waves reflected from the base surface 21 a may also hit other protrusions 30 .

Further, the portion of the protrusion 30 that is hit by the sound wave W reflected by the other protrusion 30 is not limited to the inclined surface 32 or the inclined surface 31, but also the side surfaces 34 and 35, as shown in FIG. included. Depending on the shape of the distal end surface 33 and the position of the distal end surface 33 from the base surface 21a, the distal end surface 33 may also be included in the portion of the protrusion 30 that is hit by sound waves reflected from other protrusions 30. Further, if a gap is provided between adjacent protrusions 30 on the base surface 21a of the base portion 21, the sound waves reflected from other protrusions 30 may also hit the base surface 21a. .

As described above, the sound absorber 20 absorbs the sound waves that hit the sound absorber 20. In addition, the sound absorber 20 is configured to cause at least a portion of the sound waves reflected by hitting a portion of the sound absorber 20 such as the protrusion 30 to proceed toward other portions of the sound absorber 20 such as the protrusion 30. Sound waves reflected by the sound absorber 20 can also be absorbed. In this way, the sound absorber 20 can improve the absorption rate of sound waves, and can absorb more sound waves emitted from the torsional damper 100. Therefore, the sound absorber 20 can enhance the soundproofing effect of the sound emitted from the torsional damper 100.

As described above, the sound waves weakened by the sound absorbing body 20 are insulated by the cover body 10. Thereby, the sound emitted from the torsional damper 100 is further soundproofed.

As described above, the soundproof cap 1 can enhance the soundproofing effect of the sound emitted from the torsional damper 100 by the sound absorber 20. Further, the sound absorbing body 20 is lightweight, and an increase in the weight of the soundproof cap 1 from the weight of the cover body 10 alone does not significantly change the resonance frequency of the soundproof cap 1 from the resonance frequency of the cover body 10. Furthermore, even if the soundproof cap 1 resonates, since the difference between the weight of the soundproof cap 1 and the weight of the cover body 10 alone is small, the sound absorber 20 will cause vibrations to occur around the soundproof cap when the soundproof cap 1 resonates. It does not have a large effect on pressure fluctuations.

Thus, according to the soundproof cap 1 according to the embodiment of the present invention, the soundproof performance of the soundproof cap 1 can be improved without increasing the mass of the soundproof cap 1.

Although the embodiments of the present invention have been described above, the present invention is not limited to the soundproof cap 1 according to the embodiments of the present invention, but can be applied to all aspects included in the concept of the present invention and the scope of the claims. including. Moreover, each structure may be selectively combined as appropriate so as to achieve at least some of the problems and effects described above. For example, the shape, material, arrangement, size, etc. of each component in the above embodiments may be changed as appropriate depending on the specific usage mode of the present invention.

For example, on the base surface 21a of the base body portion 21, a space may be provided between adjacent protrusions 30. Further, for example, the protrusion 30 does not need to have the tip surface 33. In this case, the inclined surface 31 and the inclined surface 32 are connected on the back side. Further, among the protrusions 30, there may be a protrusion 30 having a different height from other protrusions 30. Specifically, the position (height) of the distal end surface 33 in the axis x direction from the base surface 21a may not be the same in all the protrusions 30.

Moreover, the arrangement of the protrusions 30 may be a curved arrangement instead of a linear arrangement as described above. For example, the arrangement direction Ln may draw a curve instead of a straight line, and the protrusion group 3Ln may extend in a curve. Further, the arrangement direction Ln may be a zigzag pattern or a combination of a straight line and a curved line. Further, the arrangement directions Ln may not all be the same, and the shapes of the protrusion group 3Ln in the extending direction may not all be the same. Moreover, the shape of the protrusion 30 is not limited to the above-mentioned wedge shape.

DESCRIPTION OF SYMBOLS 1...Soundproof cap, 3Ln (n=1-m)...Protrusion part group, 10...Cover body, 11...Front surface, 12...Back surface, 12a...Outer peripheral end, 13...Outer peripheral end, 14...Rising surface, 20...Sound absorption Body, 21...Base part, 21a...Base surface, 21b...Mounting surface, 21c...Outer peripheral surface, 30...Protrusion part, 31, 32...Slanted surface, 31a, 32a...Root end, 31b, 32b...Tip, 31c, 31d , 32c, 32d... side end, 33... tip surface, 33a, 33b... side end, 34, 35... side surface, 34a, 35a... root end, 40... space, 100... torsional damper, 110... hub, 111... Boss part, 112... Rim part, 112a... Inner circumferential surface, 112b... Outer circumferential surface, 112c... End part, 113... Disc part, 114... Through hole, 115... Receiving groove, 120... Vibration ring, 121... Inner circumferential surface, 122...Outer peripheral surface, 123...V groove, 130...damper elastic body, Ln (n=1 to m)...arrangement direction, S...space, T1, T2...thickness, x, x1...axis line, W...sound wave

Claims (7)

A cover body, which is a member made of a rubber-like elastic material, and includes a pair of surfaces and an outer peripheral end portion that extends annularly to the outer peripheral side of the pair of surfaces;
a sound absorber that is a member formed from a porous material and is attached to one of the pair of surfaces of the cover body,
The sound absorbing body has a plurality of protruding parts that are parts that protrude toward the side facing the one surface of the cover body,
The soundproofing device is characterized in that each of the plurality of protrusions forms a space between it and another adjacent protrusion that is open to the side facing the one surface. The protrusion is shaped so that at least a portion of the sound wave that enters the space from the side facing the one surface and is reflected by the protrusion hits the other protrusion. The soundproofing device according to claim 1. The soundproofing device according to claim 2, wherein the space becomes narrower from the side facing the one surface toward the side facing the other of the pair of surfaces. Each of the protrusions has a surface that is inclined with respect to the one surface so as to face the side facing the one surface,
The soundproofing device according to claim 3, wherein the inclined surface forms the space. 2. The space according to claim 1, wherein each of the plurality of protrusions forms the space between the other protrusion adjacent in the direction along the one surface. Soundproofing device. Each of the protrusions has a wedge shape that becomes thinner toward the side facing the one surface,
The soundproofing device according to claim 3, wherein the protrusions are arranged so that adjacent protrusions face different directions in the direction along the one surface. 2. The soundproofing device according to claim 1, wherein the cover body can be attached to the hub of the torsional damper at the outer peripheral end so that the sound absorbing body faces the hub of the torsional damper.

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