JP6112134B2 - Sound insulation structure of the passenger compartment floor - Google Patents

Description

  The present invention relates to a sound insulation structure for a passenger compartment floor.

  In an automobile as a vehicle, it is important how to reduce noise transmitted to the passenger compartment through a floor panel, particularly road noise in the frequency band of 100HZ to 400HZ. For this reason, a floor carpet is laid on the floor panel.

  Patent Document 1 discloses a floor carpet having a multilayer structure in order to sufficiently perform sound insulation. Further, Patent Document 2 discloses a sound insulation mechanism of a floor carpet that is described using a mass and a spring system.

JP 2008-285026 A JP 2003-104135 A

  In order to enhance the sound insulation from the floor panel, it is common to increase the mass and density of the floor carpet, as used in luxury cars. However, in this case, the weight of the floor carpet is greatly increased and the cost is greatly increased.

  The present invention has been made in view of the above circumstances, and its purpose is to improve the sound insulation from the floor panel without unnecessarily increasing the mass and density of the floor carpet. The object is to provide a sound insulation structure for the room floor.

In order to achieve the above object, in the present invention, basically, the cushion material positioned on the subepidermal surface side of the floor carpet becomes an air circulation layer. The sound-insulating effect by the resonance phenomenon, that is, the sound-insulating effect by the air spring effect is obtained by communicating with the closed cross-sectional space in the reinforcing member. Specifically, as described in claim 1, a sound insulation structure for a passenger compartment floor in which a floor carpet is laid on a floor panel constituting the passenger compartment floor surface,
The floor carpet has an outer skin and a cushioning material disposed on the lower surface side of the outer skin to form an air circulation layer;
The air circulation layer is in communication with a closed cross-sectional space in a reinforcing member located near the floor carpet;
It is like that.

  According to the above solution, the sound insulation effect due to the resonance phenomenon can be sufficiently obtained by effectively using the closed cross-sectional space in the reinforcing member. In particular, the sound insulation effect can be enhanced without unnecessarily increasing the mass and density of the floor carpet, which is also preferable in terms of avoiding a significant increase in vehicle weight and a significant increase in cost.

A preferred mode based on the above solution is as described in claim 2 and the following claims. That is,
The periphery of the floor carpet is sealed so as to prevent the air circulation layer from communicating with the vehicle interior space (corresponding to claim 2). In this case, it is preferable to obtain a sufficient sound insulation effect due to the resonance phenomenon.

  The closed cross-sectional space in the reinforcing member has a sealed structure so as not to communicate with the passenger compartment or outside (corresponding to claim 3). In this case, it is preferable to obtain a sufficient sound insulation effect due to the resonance phenomenon.

The reinforcing member is a cross member joined on the floor panel and extending in the vehicle width direction,
The air circulation layer is in communication with a closed cross-sectional space in the cross member;
(Corresponding to claim 4). In this case, the sound insulation effect can be enhanced by effectively utilizing the closed cross-sectional space of the cross member that is generally provided on the floor panel.

The cross member is joined to the floor panel by its flange portion,
The flange portion of the cross member is formed with a bulging portion for communicating the air circulation layer and the closed cross-sectional space in the cross member.
(Corresponding to claim 5). In this case, the communication between the air circulation layer of the floor carpet and the closed cross-sectional space of the cross member can be easily performed using the bulging portion formed in the flange portion of the cross member. Further, it is also preferable in order not to greatly change the shape and structure of the cross member.

The skin of the floor carpet is disposed so as to cover the bulging portion,
The bulging portion extends into the cushion material;
(Corresponding to claim 6). In this case, while simplifying the structure of the connection portion with the floor carpet in the vicinity of the bulging portion, it is preferable for reliably communicating the air circulation layer and the closed cross-sectional space via the bulging portion (internal communication path). It will be a thing.

  Each of the floor carpets is configured to be divided into a plurality of pieces each having its peripheral edge sealed (corresponding to claims). In this case, when maintaining and inspecting the harness etc. arranged between the floor panel and the floor carpet while sufficiently enhancing the sound insulation effect due to the resonance phenomenon, only the small divided part of the floor carpet is used. Since it can be lifted, it is preferable for facilitating maintenance and inspection work, and easily re-sealing the peripheral edge of the divided floor carpet after maintenance and inspection.

  According to the present invention, the sound insulation from the floor panel can be improved without unnecessarily increasing the mass and density of the floor carpet.

The top view which shows the floor panel part of the vehicle to which this invention was applied. The main part perspective view which shows the cross member part in which the bulging part was formed, and shows a part in cross section. Sectional drawing which shows the relationship between the floor carpet and the cross member in the X3-X3 line equivalent part of FIG. Sectional drawing which shows the relationship between the floor carpet and the cross member in the X4-X4 line equivalent part of FIG. Sectional drawing which shows the state which has sealed the peripheral part of the floor carpet. The figure which shows the effect of this invention. The top view corresponding to FIG. 1 which shows the modification of this invention.

  In FIG. 1, reference numeral 1 denotes a floor panel that constitutes a passenger compartment floor, which is for a vehicle having two rows of front and rear seats. A rear floor panel 3 is connected to a rear portion of the floor panel 1 via a kick-up portion 2. A tunnel portion 4 bulging upward and extending in the front-rear direction is formed at the center of the floor panel 1 in the vehicle width direction. And the vehicle width direction edge part of the floor panel 1 is joined to the side sill 5 as a strength member extended in the front-back direction.

  On the floor panel 1, two sets of front and rear cross members 11 and 12 extending in the vehicle width direction are joined. The front cross member 11 is configured such that a front seat is attached to the tunnel member 4 and the side sill 5. The rear cross member 12 is configured to be attached with a seat for the rear seat, and connects the tunnel portion 4 and the side sill 5. In the figure, 7 is a pair of left and right front frames, and 8 is a dash panel that partitions the engine room and the vehicle compartment.

  The side sill 5 serves as a strength member, and a closed cross-sectional space is formed therein. Similarly, the cross members 11 and 12 serving as strength members cooperate with the floor panel 1 to form a closed sectional space. The cross members 11 and 12 are joined to the floor panel 1 by, for example, welding the flange portions 11a and 12a.

  The closed sectional space in the cross members 11 and 12 (indicated by reference numeral D11 in FIGS. 2 to 4) basically has a sealed structure in order to restrict communication (air flow) with the vehicle interior. ing. In order to secure this sealed structure, the cross members 11 and 12 are joined to the floor panel 1 by wire welding, or by spot welding and using an adhesive. However, a communication portion is partially configured for communication with an air circulation layer in a floor carpet described later (the communication portion will be described later).

  A pair of left and right floor carpets 20 are laid on the floor panel 1 with the tunnel portion 4 as a boundary. In FIG. 1, the floor carpet 20 laid on the floor panel 1 is indicated by a broken line in the drawing. Further, the left and right floor carpets 20 removed from the floor panel 1 are indicated by solid lines.

  The floor carpet 20 has a front edge overlapping the lower part of the dash panel 8, a rear edge overlapping the lower part of the kick-up part 2, and an inner edge in the vehicle width direction at the lower part of the side wall of the tunnel part 4. The outer edge in the vehicle width direction overlaps the lower part of the side sill 6. In addition, the floor carpet 20 is formed so that the part which overlaps with the cross members 11 and 12 protrudes upwards.

  As shown in FIGS. 3 and 4, the floor carpet 20 includes an outer skin 21 and a cushion material 22 that is integrated on the lower surface side and serves as a contact surface with the floor panel 1. The cushion material 22 is, for example, a general felt. The cushion material 22 part can perform air circulation, and the cushion material 22 constitutes an air circulation layer. On the other hand, the skin 21 does not substantially circulate air from the viewpoint of noise transmission. Such a floor carpet 20 has such a density and mass that it is used in a popular car or an intermediate car, and is light and inexpensive. In the embodiment, the floor carpet 20 is configured such that the cushion member 22 does not exist in the cross members 11 and 12 and only the outer skin 21 covers the cross members 11 and 12. The cushion material 22 may also be present on the surface portion of 12).

  The cross members 11, 12 are formed with communication portions for communicating the closed cross-sectional space D 11 therein with the cushion material 22 (air circulation layer) of the floor carpet 20. This communication portion will be described with reference to the cross member 11 with reference to FIGS. 2 and 4 (the cross member 12 has the same configuration as the cross member 11).

  First, as shown in FIG. 2, the flange portion 11a of the cross member 11 is formed with a bulging portion 11b that bulges partially upward. The bulging portion 11a communicates with the closed cross-sectional space D11 in the cross member 11. As is clear from FIG. 4 showing the cross section of the bulging portion 11b, the skin 21 of the floor carpet 20 covers the bulging portion 11b from above, and the bulging portion 11b extends into the cushion material 22. Is located. In this way, the air circulation layer of the floor carpet 20 serving as the cushion material 22 part and the closed sectional space D11 in the cross member 11 are communicated with each other via the bulging portion 11b (internal communication space). .

  As shown in FIG. 5 (black dots), the peripheral portion of the floor carpet 20 is sealed by the sealing material 30, and the air circulation layer formed in the cushioning material 22 portion is restricted from communicating with the vehicle interior. ing. The sealing material 30 is indicated by a one-dot chain line in FIG. FIG. 5 shows a seal between the floor carpet 20 and the tunnel portion 4, but the other peripheral portion of the floor carpet 20 is similarly sealed. The end face portion of the cushion material 22 is also sealed by the seal material 30 (the air circulation layer is restricted from communicating with the vehicle interior via the peripheral edge portion of the cushion material 22). In the embodiment, the sealing material 30 or the floor carpet 20 (peripheral edge thereof) in the vicinity thereof is pressed by the edge portion of the trim material 40 covering the tunnel portion 4 to ensure a more reliable sealing performance. is there.

  Here, the road noise is transmitted from the floor panel 1 to the vehicle interior via the floor carpet 20. At this time, in addition to noise absorption by the skin 21 and the cushion material 22 of the floor carpet 20, the air circulation layer constituted by the cushion material 22 portion and the inside of the cross member 11 (12) communicated with the air circulation layer The road noise transmitted to the vehicle interior is greatly reduced by the sound absorption effect by the resonance phenomenon using the closed cross-section space D11. In other words, the sound absorption effect due to the resonance phenomenon becomes the transmitted sound suppression effect due to the air spring effect. A large volume of air layer). For this reason, the air volume of the cushion material 22 portion of the thin floor carpet 20 is completely insufficient. For this reason, the large closed cross-sectional space D11 in the cross member 11 (12) is used. By using the cross-sectional space D11, it is possible to sufficiently obtain a sound insulation effect due to the air spring effect.

  FIG. 6 schematically shows the road noise reduction effect of the present invention, and shows the sound insulation effect by the magnitude of transmission loss. That is, the transmission loss indicates the difficulty in transmitting noise from the floor panel 1 to the vehicle interior, and the greater the transmission loss, the higher the sound insulation effect.

  In FIG. 6, the broken line corresponds to the usage mode of the conventional floor carpet 20, and the peripheral portion thereof is not sealed by the sealing material 30 and communicated with the closed cross-sectional space in the cross member 11 (12). It corresponds to the state that is not. In the conventional case, transmission loss (transmission loss of road noise into the passenger compartment) is greatly inferior in the vicinity of 400 HZ, which is a problem as road noise (occurrence of a peak value of reduced transmission loss).

  On the other hand, in FIG. 6, the solid line shows the case of the present invention. In the present invention, as compared with the conventional case, the transmission loss is remarkably improved particularly in the vicinity of 400 HZ, and unlike the conventional case, it does not have a reduced peak value in which the transmission loss is greatly reduced. Thus, it can be understood that the present invention has an extremely excellent sound insulation effect. In addition to the above, in the case of the present invention, the conventional noise characteristics are generally shifted to the low frequency side, and the transition to the low frequency side further increases the sound insulation effect. (Because the lower frequency side is less likely to be detected as noise).

  FIG. 7 shows a modification of the present invention. In this modification, the floor carpet 20 is divided into three pieces on the left and right sides and the front and rear sides with the tunnel portion 4 as a boundary, and the divided floor carpets are indicated by reference numerals 20A, 20B, and 20C. Note that the three front and rear divided boundary portions are the positions of the cross members 11 and 12.

  Thus, by increasing the number of divisions of the floor carpet 20, for example, the accessibility to harnesses disposed between the floor panel 1 and the floor carpet 20 can be enhanced. That is, it may be necessary to lift a necessary part of the floor carpet 20 for maintenance, inspection, etc. of the harnesses. In this case, it is only necessary to lift each floor carpet that is divided into small parts. (No need to lift a large floor carpet). In particular, when the periphery of the floor carpet 20 is sealed with the sealing material 30, the floor carpet 20 is lifted and then preferable from the viewpoint of workability for ensuring sealing performance when laid again at a predetermined position. .

  Although the embodiments have been described above, the present invention is not limited to the embodiments, and appropriate modifications can be made within the scope of the claims. The floor carpet 20 can be one sheet having a large area substantially the same as that of the floor panel 1, or can be divided into an appropriate number of sheets. The closed cross-sectional space of the reinforcing member that communicates with the air circulation layer (the cushion material 22 portion) of the floor carpet 20 is, for example, a closed cross-sectional space in the side sill 6 or is not shown but is joined to the lower surface of the floor panel 1. A closed cross-sectional space in an appropriate reinforcing member, such as a closed cross-sectional space in a floor frame extending in the front-rear direction, can be used. The periphery of the floor carpet 20 can be prevented from being sealed so as to restrict communication with the vehicle interior.

  If the reinforcing member is drilled to reduce weight, etc., and it is difficult to ensure the tightness of the closed cross-sectional space, a node member that partitions the closed cross-sectional space is provided to improve the airtightness. It is also possible to ensure a closed cross-sectional space. It should be noted that the airtightness or seal referred to in the present invention is sufficient as long as noise (vibration) in a band of about 100HZ to 400HZ, which is particularly problematic as road noise, is not easily passed (no air leaks at all). Strictness is not required). A cylindrical body (hose) formed of a synthetic resin, rubber, or the like and having a large number of communication holes is connected to the bulging portion 11b, and the cylindrical body extends long in the cushioning material 22, that is, in the air circulation layer. In addition, a wide range of the air circulation layer may be communicated with the closed cross-sectional space through the communication hole (tubular body). By connecting such a cylindrical body to a side surface of a reinforcing member having a closed cross-sectional space such as the cross member 11, the air circulation layer and the closed cross-sectional space can be communicated with each other in addition to the flange portion 11 a for joining. In addition, the selection range of the reinforcing member and its communication position is expanded. Of course, the object of the present invention is not limited to what is explicitly stated, but also implicitly includes providing what is substantially preferred or expressed as an advantage.

  The present invention is preferable in enhancing the sound insulation effect by effectively using the floor carpet.

1: floor panel 4: tunnel part 5: side sill 11: cross member 11a: flange part 11b: bulge part 12: cross member 20: floor carpet 21: skin 22: cushion material (air circulation layer)
D11: Closed section space

Claims (7)

A sound insulation structure of a passenger compartment floor in which a floor carpet is laid on a floor panel constituting the passenger compartment floor surface,
The floor carpet has an outer skin and a cushioning material disposed on the lower surface side of the outer skin to form an air circulation layer;
The air circulation layer is in communication with a closed cross-sectional space in a reinforcing member located near the floor carpet;
A sound insulation structure for the passenger compartment floor. In claim 1,
A sound insulation structure for a vehicle compartment floor, wherein a peripheral portion of the floor carpet is sealed so as to prevent the air circulation layer from communicating with the vehicle interior space. In claim 1 or claim 2,
A sound insulation structure for a vehicle compartment floor, wherein the closed cross-sectional space in the reinforcing member has a sealed structure so as not to communicate with the vehicle interior or the outside. In any one of Claims 1 thru | or 3,
The reinforcing member is a cross member joined on the floor panel and extending in the vehicle width direction,
The air circulation layer is in communication with a closed cross-sectional space in the cross member;
A sound insulation structure for the passenger compartment floor. In claim 4,
The cross member is joined to the floor panel by a flange portion thereof,
The flange portion of the cross member is formed with a bulging portion for communicating the air circulation layer and the closed cross-sectional space in the cross member.
A sound insulation structure for the passenger compartment floor. In claim 5,
The skin of the floor carpet is disposed so as to cover the bulging portion,
The bulging portion extends into the cushion material;
A sound insulation structure for the passenger compartment floor. In claim 2,
A sound insulation structure for a passenger compartment floor, wherein the floor carpet is divided into a plurality of pieces each having a peripheral edge sealed.

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