JP2014084015A - Sound insulation structure for cabin rear part of automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce tire pattern noise and other noise which propagate upstream through air in an exhaust flow passage in a cabin rear part and enter the inside of a cabin, in a sedan-type automobile including an extractor structure for exhausting air from the inside of the cabin to the outside of the cabin in the cabin rear part.SOLUTION: According to the present invention, a sound insulation structure for a cabin rear part of an automobile includes: in the rear part of a tray trim, a cabin side opening connecting a clearance between an automobile body panel constituting the top surface of the inside of a trunk room and the tray trim to the inside of a cabin; in the front part of the automobile body panel, a trunk side opening connecting the clearance between the tray trim and the automobile body panel to the inside of the trunk room; and a sound absorption layer on the undersurface of the tray trim. An exhaust flow passage is constituted by a passage entering a rear package tray part from the cabin side opening, passing through the clearance, passing out of the trunk side opening, and then reaching an exhaust port through the inside of the trunk room.

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound insulation structure for a rear part of a vehicle compartment, and more particularly to a sound insulation structure for a sedan type vehicle equipped with an extractor structure for exhausting air from the compartment to the outside of the compartment. Belonging to the field.

  Conventionally, when an air conditioner is operated by taking outside air into a vehicle interior in an automobile, an extractor structure for exhausting air from the vehicle interior to the exterior of the vehicle interior is adopted at the rear of the vehicle for ventilation of the air conditioning wind or the like. .

  On the other hand, a sedan-type automobile is generally provided with a rear package tray portion to which a speaker or the like is attached at the rear of the rear seat back. The rear package tray portion is mainly composed of a package tray panel that partitions the vehicle compartment and the trunk room, and a tray trim that extends parallel to the upper side.

  For example, in Patent Document 1, a rear parcel part (corresponding to a “rear package tray part”) is provided as an extractor structure of a sedan type automobile, and a rear parcel panel (corresponding to a “package tray panel”) and a rear parcel constituting the rear parcel part. Disclosed are trims (corresponding to "tray trims") that each have ventilation openings so as to provide a straight ventilation path, and exhaust air from the passenger compartment to the trunk room through these ventilation openings. .

  However, in this conventional structure, since the exhaust port serving as the outlet of the exhaust passage is located in the vicinity of the rear wheel, for example, noise caused by tire pattern noise propagates through the air in the exhaust passage from the exhaust port. As a result, there was a problem of intruding back into the passenger compartment and causing discomfort to the passengers.

  In addition, in the thing of patent document 1, a partition is provided in the space in the rear parcel part which communicates with openings other than the opening for ventilation, and openings other than the opening for ventilation are divided, and only the opening for ventilation communicates. By using the ventilation space as a ventilation path, the resonance frequency of noise generated in the trunk room is reduced, and the sound pressure level of noise entering the vehicle compartment is reduced.

  However, in Patent Document 1, since the ventilation openings provided on the vehicle compartment side and the trunk room side of the rear parcel part are provided as a straight ventilation path, noise from the trunk room is generated by the vehicle interior. The noise reduction or sound insulation effect is not sufficient, and further improvement in sound insulation is desired.

Japanese Patent Application Laid-Open No. 07-187010

  Therefore, an object of the present invention is to effectively reduce tire pattern noise and other noises that propagate through the air in the exhaust passage at the rear of the passenger compartment and enter the passenger compartment.

  In order to solve the above-described problems, the vehicle compartment rear sound insulation structure according to the present invention is configured as follows.

First, the invention according to claim 1 of the present application is
A rear package tray having a vehicle body panel constituting a top surface inside the trunk room, and a tray trim extended above the vehicle body panel with a predetermined gap from the vehicle body panel; and It is a sound insulation structure at the rear of the passenger compartment of a sedan type car with an exhaust port on the side,
The tray trim has a vehicle interior side opening that connects the vehicle interior and the gap at a rear portion thereof,
The vehicle body panel has a trunk side opening that connects the gap and the inside of the trunk room at a front portion thereof,
A sound absorbing layer is provided on the lower surface of the tray trim,
An exhaust passage is formed in the rear package tray part from the passenger compartment side opening part, through the gap and from the trunk side opening part to the exhaust port through the trunk room. It is characterized by.

The invention according to claim 2 of the present application is the invention according to claim 1,
The rear package tray portion is connected to the front of the gap between the vehicle body panel and the tray trim, and an extended space portion in which a distance between the vehicle body panel and the tray trim is wider than the gap. Have
The trunk side opening is connected to the expansion space.

Further, the invention according to claim 3 of the present application is the invention according to claim 2, wherein the vehicle body panel is connected so that a flat surface package tray panel and a vertical wall portion of the package tray panel hang from the front end of the package tray panel. And an L-shaped member provided so that the horizontal wall portion is directed forward from the lower end of the vertical wall portion,
The gap is formed between the package tray panel and the tray trim, and the expansion space is formed between the lateral wall portion of the L-shaped member and the tray trim.
The trunk side opening is provided in the vertical wall of the L-shaped member.

  With the above configuration, according to the invention according to each claim of the present application, the following effects can be obtained.

  The air in the passenger compartment is exhausted into the trunk room through the exhaust passage of the rear package tray, that is, the opening on the passenger compartment side, the gap between the tray trim and the package tray panel, and the opening on the trunk room side. Further, the air is exhausted from the inside of the trunk room to the outside through an exhaust port on the side of the trunk room.

  Noise outside the vehicle propagates through the air in the above-described exhaust flow path and enters from the exhaust port to the interior of the vehicle in the direction opposite to the exhaust.

  Here, since the exhaust flow path described above is reversed from the rear to the front at the opening on the vehicle compartment side, the noise that goes back through the flow path also enters the vehicle interior while reversing the direction. Moreover, the energy of sound is reduced (sound interferes) due to the opposite direction of the propagation path.

  Further, when the noise propagates through the air in the gap, the sound is absorbed by the sound absorbing layer extending along this propagation direction.

  Therefore, according to the first aspect of the present invention, while the noise propagates through the air in the gap constituting a part of the exhaust flow path and goes back from the trunk side opening to the passenger compartment side opening, The sound is absorbed by the sound absorbing layer provided on the lower surface, and at the time of inversion at the passenger compartment side opening, the sound energy is reduced (sound interferes) due to the opposite direction of the propagation path. It is possible to reduce the noise that propagates through the air in the exhaust passage from the exhaust port and enters the vehicle interior.

  According to the second aspect of the invention, the propagation path widens when noise enters the expansion space from the trunk side opening, and the propagation path becomes narrower when the noise enters the gap from the expansion space. The sound energy decreases (sound interference) due to the sudden expansion and contraction of the sound. Therefore, further reduction of noise can be realized by providing the expansion space part in the middle of the propagation path (exhaust flow path) in the rear package tray part.

  According to the third aspect of the present invention, as described above, there is a reduction in sound energy (sound interference) due to a sudden expansion / reduction of the propagation path at the entrance / exit of the step-down space that is the expansion space. As it happens, the noise is attenuated.

  In addition, since the trunk side opening is provided in the vertical wall portion of the L-shaped member, the exhaust flow path is reversed again from the front to the rear in the step-down space, and the direction of the noise going back through the flow path further increases. Since it penetrates into the gap while reversing, the noise is attenuated more effectively.

It is a partial cross section perspective view which shows the compartment of the motor vehicle in one Embodiment of this invention. It is side surface sectional drawing which shows the vehicle interior rear part of the motor vehicle. FIG. 3 is a rear cross-sectional view (cross-sectional view taken along the line A-B-C-D in FIG. 2) of the rear part of the same vehicle as viewed from the rear. It is side surface sectional drawing (partially enlarged view of FIG. 2) which shows the rear package tray part of the motor vehicle. It is a perspective view which shows the lower surface of the tray trim single-piece | unit of the same motor vehicle. It is a graph which shows the sound insulation performance of the same car.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a vehicle compartment rear sound insulation structure according to the present invention will be described with reference to FIGS. 1 to 6.

  As shown in FIG. 1, a rear package tray portion 2 extending horizontally above the trunk room T is provided behind the seat back S of the rear seat at the rear portion of the sedan type automobile 1. A rear glass G (not shown in FIG. 1) is provided above the rear package tray portion 2, and a trunk lid L is provided behind.

  FIG. 2 is a side sectional view in which the center of the rear part of the above-described vehicle compartment is cut in the front-rear direction.

  As shown in FIG. 2, the rear package tray section 2 extends in parallel with a package tray panel 3 constituting the top surface inside the trunk room T with a gap P of a predetermined distance above the package tray panel 3. Tray trim 4.

  The package tray panel 3 is formed in a planar shape as a whole, and an L-shaped member 5 extending in the vehicle width direction is connected to the front end thereof. The rear part of the package tray panel 3 constitutes a rear deck member M extending in the vehicle width direction.

  The package tray panel 3 in the present embodiment is provided with a plurality of speaker mounting holes 3a (see FIG. 1).

  The tray trim 4 is formed in a planar shape as a whole, but its front end is bent so as to hang downward. A compartment side opening 6 having a predetermined opening area is provided at the rear of the tray trim 4. The vehicle interior side opening 6 is provided with a mesh sheet 7 having air permeability so as to cover the entire surface thereof.

  Further, the tray trim 4 is provided with a sound absorbing material 8 on its lower surface. The sound absorbing material 8 is formed of a nonwoven fabric using resin fibers such as polyester. The sound absorbing material 8 may also be formed of a porous material such as felt or urethane having a sound absorbing effect.

  The L-shaped member 5 includes a vertical wall portion 5a and a horizontal wall portion 5b (see FIG. 4). The L-shaped member 5 is connected so that the vertical wall portion 5a hangs down from the front end of the package tray panel 3, and the horizontal wall portion 5b is vertical. It is provided so as to go from the lower end of the wall portion 5a toward the front of the vehicle. Moreover, the trunk side opening part 9 which has a predetermined opening area is provided in the vertical wall part 5a.

  The left and right ends of the L-shaped member 5 are connected to the left and right rear pillar panels 10, respectively. A step-down space between the L-shaped member 5 and the upper tray trim 4 between the left and right rear pillar panels 10 and having a vertical distance larger than the gap P between the package tray panel 3 and the tray trim 4. Part Q is formed. The step-down space Q is connected to the trunk room T via the trunk-side opening 9.

  The trunk room T includes a package tray panel 3 and an L-shaped member 5 on the inner ceiling, left and right side trims 11 on the side walls, and a trunk mat 12 on the floor surface. The upper end of the side trim 11 constituting the side wall has a gap R of a predetermined distance between the package tray panel 3 constituting the ceiling and the lower surface of the L-shaped member 5.

  On the side of the trunk room T, there are a wheel house 13 that covers the periphery of the rear wheel J (part of the imaginary line), a rear pillar panel 10 that supports the wheel house 13 from the periphery, and a rear fender 14 that covers the rear pillar panel 10 from the outside (FIG. 3). Reference) is provided.

  The rear pillar panel 10 is provided with an exhaust port 15 at the lower rear portion of the rear wheel J for communicating the space inside and outside the rear pillar panel 10. The exhaust port 15 may be provided with a check valve (not shown) that allows air or water to flow only outside.

  FIG. 3 is a side cross-sectional view of the rear part of the vehicle compartment of FIG. 2 cut in the left-right direction along the cross section ABCD. Since the rear part of the passenger compartment has a substantially symmetrical structure, the rear left part of the passenger compartment is not shown.

  As shown in FIG. 3, the side trim 11 constituting the side wall of the trunk room T has a lower portion extending in the vehicle width direction along the wheel house 13 and the rear pillar panel 10 behind the rear wheel J.

  There is a space V between the side trim 11 and the rear pillar panel 10, but the space V is located between the side trim 11 and the rear pillar panel 10 in front of the rear end 13 a (see FIG. 2) of the wheel house 13. It is blocked by a wheel house 13.

  The upper portion of the space V is connected to the trunk room T via a gap R and connected to the space W between the rear pillar panel 10 and the rear fender 14 via an exhaust port 15 at the lower rear portion of the rear pillar panel 10. Has been. Further, the space W is open to the outside of the vehicle at the lower part.

  FIG. 5 is a perspective view showing the lower surface of the single tray trim 4.

  As shown in FIG. 5, the passenger compartment side opening 6 in the present embodiment has a belt-like outer shape extending in the vehicle width direction along the lower end portion of the rear glass G adjacent in a plan view, and two symmetrically provided. It has been.

  Also, the tray trim 4 is provided with two operation parts K symmetrically for releasing the fixation of the seat back S when the seat back S is tilted forward. The tray trim 4 may be provided with a speaker mounting hole 4a and a high mount brake lamp mounting hole 4b as required.

  Furthermore, the sound absorbing material 8 in the present embodiment excludes the portion of the lower surface of the tray trim 4 where the vehicle compartment side opening 6, the operation portion K, the speaker mounting hole 4a, the high mount brake lamp mounting hole 4b, and the like are provided. It is affixed to the part with an adhesive or the like.

  Note that a recess (not shown) for placing and storing articles may be provided on the upper surface of the tray trim 4.

  Next, the exhaust passage (extractor structure) where the air in the vehicle compartment is exhausted through the vehicle rear structure will be described.

  FIG. 4 is an enlarged side view of the periphery of the rear package tray 2 in FIG. In addition, the solid line arrow in FIGS. 1-4 shows the exhaust flow path and its direction.

  First, as shown in FIG. 4, the air in the passenger compartment flows into the gap P between the package tray panel 3 and the tray trim 4 through the passenger compartment-side opening 6 while reversing from rearward to forward. The air flowing backward through the gap P flows into the step-down space Q between the L-shaped member 5 and the tray trim 4. The air that has flowed into the step-down space Q flows into the trunk room T through the trunk-side opening 9 while reversing from the front to the rear.

  Next, as shown in FIG. 2, from the gap R between the upper end of the side trim 11 and the lower surface of the package tray panel 3 and the L-shaped member 5 from the trunk room T to the side trim 11 forming the side wall of the trunk room T and the outside thereof. It flows in a space V between a certain rear pillar panel 10.

  Finally, as shown in FIG. 3, the air that has flowed into the space V from the gap R flows toward the exhaust port 15 provided in the lower rear portion of the rear pillar panel 10, and further passes through the exhaust port 15 and passes through the rear pillar panel. It flows in the space W between 10 and the rear fender 14. The air that has flowed into the space W flows out of the vehicle from the portion of the space W that is open to the outside of the vehicle.

  As described above, the air in the passenger compartment is in the order of the passenger compartment side opening 6 → gap P → stepped space Q → trunk side opening 9 → trunk room T → gap R → space V → exhaust port 15 → space W. Then, the air is exhausted out of the vehicle through an exhaust passage constituted by these openings and spaces.

  Next, a noise propagation path will be described. Noise outside the vehicle propagates through the air in the above-described exhaust passage and goes back in the opposite direction to enter the vehicle interior. The dotted line arrows in FIG. 4 indicate the propagation path and direction of the noise going back through the exhaust flow path, and although not shown in FIGS. 1 to 3, the noise is the exhaust flow path (solid line arrow) described above. Is propagated in the opposite direction.

  First, as shown in FIG. 3, noise caused by tire pattern noise or the like generated at the rear wheel J passes through the exhaust port 15 of the rear pillar panel 10 from the lower part of the space W between the rear fender 14 and the rear pillar panel 10. Thus, the vehicle enters the space V between the side trim 11 and the rear pillar panel 10 that form the side wall of the trunk room T. Next, the vehicle enters the trunk room T through a gap R between the upper end of the side trim 11 located forward and upward from the space V and the lower surface of the package tray panel 3.

  Next, as shown in FIG. 2, the noise that has entered the trunk room T passes through the trunk-side opening 9 of the L-shaped member 5 from the inside of the trunk room T, and the L-shaped member 5 and the tray trim 4 at the front. Intrudes into the stepped-down space Q defined by.

  Finally, as shown in FIG. 4 (see dotted arrows), the noise that has entered the step-down space portion Q is reversed from the front to the rear and the direction from the step-down space Q to the package tray panel 3 and the tray trim 4. The vehicle enters the gap P between the vehicle body and the vehicle body. Further, from the gap P, the vehicle enters the vehicle interior through the vehicle compartment side opening 6 of the tray trim 4 while reversing the direction from the rear to the front.

  As described above, the noise outside the vehicle is in the order of the space W → the exhaust port 15 → the space V → the gap R → the trunk room T → the trunk side opening 9 → the stepped space part Q → the gap P → the compartment side opening 6 in this order. The vehicle enters the passenger compartment through a propagation path composed of these spaces and openings.

  Next, how the noise propagating in the propagation path is absorbed when passing through the rear package tray 2 will be described with reference to FIG.

  First, the noise that has entered the trunk room T is attenuated when entering the gap P between the package tray panel 3 and the tray trim 4 after entering the step-down space Q through the trunk-side opening 9.

  This is because the propagation path widens when noise enters the step-down space Q from the trunk side opening 9, and the propagation path narrows again when entering the gap P from the step-down space Q. This is because sound energy is reduced (sound interference) due to excessive expansion and reduction, and sound energy is consumed.

  Further, when the noise passes through the stepped space portion Q, the trunk side opening 9 is provided in the vertical wall portion 5a of the L-shaped member 5, so that the exhaust passage is directed forward in the stepped space portion Q. Therefore, the noise that goes back through the flow path also enters the gap P while its direction is reversed. Even during this inversion, the energy of the sound (sound interference) due to the opposite direction of the propagation path occurs in the step-down space Q, so that the noise is more effectively attenuated.

  Next, the noise that has entered the gap P from the step-down space Q is absorbed by the sound-absorbing material 8 extending along this propagation direction when the air in the gap P is propagated to the passenger compartment opening 6. .

  The principle of sound absorption by the sound absorbing material 8 is that when sound incident on the sound absorbing material 8 propagates inside, a part of sound energy is converted into heat energy and dispersed by the internal friction.

  Finally, since the exhaust flow path is reversed from the rearward direction to the frontward direction in the passenger compartment side opening 6, noise going back through this flow path also enters the passenger compartment while reversing the direction from the passenger compartment side opening 6. . Also during this reversal, noise is attenuated because sound energy is reduced (sound interferes) due to opposing propagation path directions.

  As described above, according to the present embodiment, sound energy (sound interference) due to rapid expansion and reduction of the propagation path in the step-down space Q, sound absorption in the gap P, and the passenger compartment side Noise from the outside of the vehicle is attenuated by a reduction in sound energy (sound interference) caused by the opposite direction of the propagation path at the opening 6.

  Next, the sound insulation performance according to the present embodiment will be described.

FIG. 6 is a graph showing the results of experiments on how the noise changes when the opening area of the trunk side opening 9 in the package tray panel 3 is changed for the present embodiment and the following comparative example. Is. The horizontal axis of the graph represents the opening area (mm ² ) of the trunk side opening 9, and the vertical axis represents the difference from the sound pressure level (background noise) when the trunk side opening 9 is completely closed. Is a sound pressure level difference (dB).

  In the present embodiment, as already described, the trunk side opening 9 is provided in the vertical wall portion 5 a of the L-shaped member 5 in front of the rear package tray portion 2, and the sound absorbing material 8 is provided on the lower surface of the tray trim 4. Thus, it is provided between the trunk side opening 9 and the passenger compartment side opening 6.

  On the other hand, the comparative example is different from the present embodiment in that the trunk side opening 9 is provided directly below the passenger compartment side opening 6. In the comparative example, the sound absorbing material 8 is provided on the lower surface of the tray trim 4 as in the present embodiment.

  As shown in FIG. 6, it can be seen that even if the opening area of the trunk side opening 9 is changed, the sound pressure level difference of the present embodiment is smaller than the sound pressure level difference of the comparative example.

  That is, rather than providing the trunk-side opening 9 directly below the passenger compartment-side opening 6, the trunk-side opening 9 provided on the vertical wall 5a of the L-shaped member 5 in front of the rear package tray 2 is more The noise that propagates through the air in the exhaust passage and enters the vehicle interior is actually reduced.

  As described above, the sound insulation performance according to the present embodiment was confirmed by experiments.

  In the present embodiment, the separate sound absorbing material 8 is attached to the lower surface of the tray trim 4, but the tray trim 4 itself is formed of a multilayer structure member whose bottom layer is composed of a porous sound absorbing layer. Also good.

  Further, in the present embodiment, the step-down space portion Q is formed as an expansion space portion in the rear package tray portion 2, but this expansion space portion may not be provided.

  Further, when providing the expansion space portion, the front portion of the package tray panel 3 or the tray trim 4 is expanded regardless of the L-shaped member 5, and the gap P is formed between the package tray panel 3 and the tray trim 4. Alternatively, an extended space portion having a wide vertical distance between the package tray panel 3 and the tray trim 4 may be formed.

  Note that the present invention is not limited to the illustrated embodiments, and it goes without saying that various improvements and design changes can be made without departing from the scope of the present invention.

  As described above, according to the present invention, in the sedan type automobile provided with the extractor structure for exhausting from the passenger compartment to the exterior of the passenger compartment, the air in the exhaust passage at the rear of the passenger compartment is obtained. Since it is possible to effectively reduce the tire pattern noise and other noises that propagate and invade retrospectively into the vehicle interior, there is a possibility of being suitably used in the manufacturing industry of this type of automobile.

1: Sedan type car 2: Rear package tray part 3: Package tray panel (body panel)
4: Tray trim 5: L-shaped member 5a: Vertical wall 6: Vehicle compartment side opening 8: Sound absorbing material (sound absorbing layer)
9: Trunk side opening 15: Exhaust port P: Gap Q: Stepped space (expansion space)
T: Trunk room

Claims (3)

A rear package tray having a vehicle body panel constituting a top surface inside the trunk room, and a tray trim extended above the vehicle body panel with a predetermined gap from the vehicle body panel; and It is a sound insulation structure at the rear of the passenger compartment of a sedan type car with an exhaust port on the side,
The tray trim has a vehicle interior side opening that connects the vehicle interior and the gap at a rear portion thereof,
The vehicle body panel has a trunk side opening that connects the gap and the inside of the trunk room at a front portion thereof,
A sound absorbing layer is provided on the lower surface of the tray trim,
An exhaust passage is formed in the rear package tray part from the passenger compartment side opening part, through the gap and from the trunk side opening part to the exhaust port through the trunk room. A sound insulation structure at the rear of the vehicle compartment, characterized by The rear package tray portion is connected to the front of the gap between the vehicle body panel and the tray trim, and an extended space portion in which a distance between the vehicle body panel and the tray trim is wider than the gap. Have
The vehicle interior rear sound insulation structure according to claim 1, wherein the trunk side opening is connected to the expansion space. The vehicle body panel is connected to a flat surface-shaped package tray panel so that the vertical wall portion hangs down from the front end of the package tray panel, and the horizontal wall portion is directed forward from the lower end of the vertical wall portion. And an L-shaped member provided in
The gap is formed between the package tray panel and the tray trim, and the expansion space is formed between the lateral wall portion of the L-shaped member and the tray trim.
The vehicle interior rear sound insulation structure according to claim 2, wherein the trunk side opening is provided in the vertical wall portion of the L-shaped member.

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