Patent Description:
It is known that in a vehicle such as an automobile, a sound-absorbing material is used for absorbing unpleasant noise, while designing an interior of the vehicle. Furthermore, a multilayer trim part for vehicles is known which comprises, for absorbing noise, a porous intermediate film layer between two fiber layers, and in which an overall airflow resistance (AFRoverall in a unit of Ns/m<NUM>) and an overall density ρ (kg/m<NUM>) have a relation of <NUM> < AFRoverall-10ρ < <NUM> in a region having a thickness from <NUM> to <NUM> (e.g., see PTL <NUM>).

Prior art document <CIT> refers to sound absorbing materials which are disposed respectively to a head lining, a dash insulator and a floor carpet disposed in the passenger compartment. The first sound absorbing material is capable of absorbing sound within a first frequency range of from <NUM> to <NUM>. The second sound absorbing material is capable of absorbing sound within a second frequency range of from <NUM> to <NUM>. The third sound absorbing material is capable of absorbing sound within a third frequency range of from <NUM> to <NUM>. Each sound absorbing material is formed of a unshaped polyester fiber mixture which is prepared by mixing polyester (main) fibers and binder fibers for bonding the polyester fibers to each other.

Prior art document <CIT> shows a multifunction sub cushion for vehicles is provided to release the discomfort of a neck by simultaneously supporting the back head and neck part of a passenger including a driver. The multifunction sub cushion for vehicles comprises a main body member. The main body member comprises a buffer member, a supporting member and a cover member. The buffer member is made of the soft material supporting the brain and neck of a passenger. The supporting member is installed inside the buffer member and protects a neck from impact. The supporting member has the neck support of the hard material which relatively harder than the buffer member. The cover member protects the outside of the buffer member.

Prior art document <CIT> describes a cover for an interior component of a vehicle. The cover comprises an exterior cover element and a back coating formed at least as a back barrier bonded to the exterior cover element. The back barrier is formed by a plastic fibers material.

Prior art document <CIT> discloses a multilayer sound attenuating trim part for a vehicle, in particularly for a trim part or cladding used in the interior of a car, for instance as an inner dash or as part of the floor covering or for the exterior of a vehicle, for instance as a trim part or cladding in the engine bay area or as part of an under body trim part as well as to the method of producing a part.

In a conventional dash insulator or carpet, however, an airflow resistance is set to be rather high, to increase sound-absorbing effect, and the sound-absorbing effect is exerted even in a frequency band of conversation between passengers. Consequently, there is a problem that if a conventional sound-absorbing material that has high airflow resistance is disposed, for example, on a back surface of a front seat close to passenger's ears, a passengers in the vehicle less easy to have conversation between a passenger in a rear seat and a passenger in a front seat because of absorbing voice of the conversation.

In view of the above problem, an object of the present invention is to provide vehicle front seat with a sound-absorbing material that is capable of absorbing unpleasant noise in a vehicle interior while maintaining clear conversation between a passenger in a rear seat and a passenger in a front seat.

The object underlying the present invention is achieved by a vehicle front seat according to independent claim <NUM>. Preferred embodiments are defined in the respective dependent claims.

To solve the above problem and achieve the object, a vehicle front seat is proposed which comprises a sound-absorbing material that is mounted to a back side of the vehicle front seat and that comprises a main body in which at least a fiber material and a surface are integrally formed, wherein a sound-absorbing section is formed in at least one part of the main body and it mounted to the back side of the vehicle front seat within a range in which a vertical distance Elh downward from a lower surface of a head rest of the front seat to the sound-absorbing section is from <NUM> to <NUM>, and an airflow resistance AFR determined in units of Ns/m<NUM> and the vertical distance Elh determined in units of m satisfy a relation of: <MAT> and.

the airflow resistance AFR is set for the sound-absorbing section by having a thickness for the sound-absorbing section which is different from the thickness of other areas of the main body.

Furthermore, in the vehicle front seat according to the aspect of the present invention, in the sound-absorbing section, a non-ventilating material is applied on the fiber material on the opposite side of the surface.

Additionally, in the vehicle front seat according to the aspect of the present invention, the non-ventilating material is a non-ventilating thin film.

In addition, in the vehicle front seat according to the aspect of the present invention, the sound-absorbing section comprises a foam material such as urethane having a thickness of <NUM> or more and <NUM> or less between the fiber material and the surface material.

Furthermore, in the vehicle front seat according to the aspect of the present invention, in the sound-absorbing section, a sound absorption coefficient at a frequency of <NUM> or more is set to be higher than a sound absorption coefficient at a frequency that is less than <NUM>.

The present invention produces an effect that unpleasant noise in a vehicle interior can be absorbed, while maintaining clear conversation between a passenger in a rear seat and a passenger in a front seat.

Hereinafter, an embodiment of a sound-absorbing material for vehicles installed to a vehicle front seat <NUM> will be described with reference to the drawings. <FIG> is a perspective view illustrating a state of a sound-absorbing material for vehicles <NUM> according to the embodiment seen from the surface. Furthermore, <FIG> is a perspective view illustrating a state where the sound-absorbing material for vehicles <NUM> according to the embodiment is attached to a back side of a front seat <NUM> in a vehicle interior.

As shown in <FIG> and <FIG>, in the sound-absorbing material for vehicles <NUM>, a main body <NUM> is integrally formed to be attachable to a vehicle interior without providing an fixing hole in the surface. An approximate center of the main body <NUM> is provided with a sound-absorbing section <NUM> in which a predetermined airflow resistance is set. In the sound-absorbing section <NUM>, a thickness of a region shown by diagonal lines in <FIG> may be larger than a thickness of another region so that sound absorption characteristics of the region are different from those of the other region. For example, in the sound-absorbing section <NUM>, the sound absorption characteristics are set so that sound absorption from conversation between passengers is inhibited, while absorbing another unpleasant noise in the vehicle.

Additionally, in the main body <NUM>, a rim section <NUM> is formed by compressing peripheral. Furthermore, in the rim section <NUM>, a bent section <NUM> is formed, for example, by bending a side part and upper part of the main body <NUM>.

Then, in the sound-absorbing material for vehicles <NUM>, the bent section <NUM> formed in the side part and upper part of the main body <NUM> is fixed along the back side of the front seat <NUM> in accordance with roundness around a back surface of the front seat <NUM>. Here, the rim section <NUM> formed in a lower part of the main body <NUM> is bent downward from the front seat <NUM>.

<FIG> is a view illustrating a configuration of a back side of the sound-absorbing material for vehicles <NUM> installed to a vehicle front seat <NUM>. As shown in <FIG>, the sound-absorbing section <NUM> is disposed in the approximate center of the main body <NUM> so that a region provided with a sound-absorbing function widens. Furthermore, on a back side of the rim section <NUM>, a plurality of fixed parts <NUM> to be fixed to the front seat <NUM> are arranged, for example, via a space being from <NUM> to <NUM>. Furthermore, when the sound-absorbing material for vehicles <NUM> is attached to the front seat <NUM>, load is applied to the space between the fixed part <NUM> and the fixed part <NUM>. A shape and structure of the fixed part <NUM> will be described later with reference to <FIG>. Then, the rim section <NUM> is formed, by compression molding, to be continuous among the plurality of fixed parts <NUM>, and the bent section <NUM> is formed. Furthermore, the sound-absorbing section <NUM> is provided adjacent to the rim section <NUM> via a stepped part on an inner side of the rim section <NUM>, and among the plurality of fixed parts <NUM>, to absorb sound of the vehicle interior. Additionally, to form the bent section <NUM>, at least a part of the rim section <NUM> is bent almost along the stepped part so that the rim section is continuous among the plurality of fixed parts <NUM>.

<FIG> is a view schematically showing a cross section of the integrally formed main body <NUM>. As shown in <FIG>, the main body <NUM> includes a configuration where, for example, a first fiber material <NUM>, a second fiber material <NUM>, PE powder <NUM> and a surface <NUM> are stacked and integrally formed.

The first fiber material <NUM> is, for example, made of <NUM>/m<NUM> of polyethylene terephthalate (PET). The second fiber material <NUM> is, for example, made of <NUM>/m<NUM> of PET. The PE powder <NUM> is, for example, a powder body made of <NUM>/m<NUM> of polyethylene (PE). The surface <NUM> is, for example, a surface material made of <NUM>/m<NUM> of tricot or the like.

<FIG> is a perspective view illustrating an outline of the fixed part <NUM>. The fixed part <NUM> is, for example, made of plastic, and includes a configuration where an adhesive surface <NUM> is provided on a lower surface of a bonding protrusion <NUM>. The bonding protrusion <NUM> is formed to be mechanically couplable to each of a plurality of bonding parts (not shown) provided on the back side of the front seat <NUM> by use of material elasticity without using any adhesives. The adhesive surface <NUM> is provided to fix the fixed part <NUM> to the rim section <NUM> of the sound-absorbing material for vehicles <NUM> with the adhesive.

Next, a structure of the main body <NUM> will be described in detail.

<FIG> is a view showing a cross-sectional structure of the main body <NUM>. <FIG> is a view showing the cross-sectional structure along the A-A line shown in <FIG>. <FIG> is a view showing a cross-sectional structure along the B-B line shown in <FIG>. Furthermore, each of <FIG> is an enlarged view of the rim section <NUM> in <FIG>.

As shown in <FIG>, the sound-absorbing section <NUM> is not compressed, unlike the rim section <NUM>, and is provided in the almost center of the main body <NUM>, in which the predetermined airflow resistance is set. Furthermore, as shown in <FIG>, the sound-absorbing section <NUM> is not compressed, unlike the rim section <NUM>, and the almost center of the main body <NUM> has a thickness larger than that of a corresponding part shown in <FIG>, and has sound absorption characteristics changed from those of the part shown in <FIG>.

Additionally, the rim section <NUM> is bent at a position X and a position Y, and has an end curved, to form the bent section <NUM>. Here, as shown in <FIG>, the bent section <NUM> is formed so that in a part bent at the position X, a ratio of an actual width (an actual length) L2 to a straight line distance width L1 is larger than <NUM> and smaller than <NUM>. That is, in the bent section <NUM>, a ratio of the actual width to a straight line distance width from the stepped part to an outer end of the rim section <NUM> is larger than <NUM> and smaller than <NUM>. A plurality of stepped parts are provided, and a stepped part on a sound-absorbing section <NUM> side is higher than a stepped part on a rim section <NUM> side.

Furthermore, as shown in <FIG>, the bent section <NUM> is formed so that in the parts bent at the position X and the position Y, the ratio of the actual width L2 to the straight line distance width L1 is larger than <NUM> and smaller than <NUM>. That is, in a case where the bent section <NUM> is bent a plurality of times in a width direction, each of a ratio of the actual width L2 to the straight line distance width L1 in each bent part and a ratio of the actual width L2 to an overall straight line distance width L1 is set to be larger than <NUM> and smaller than <NUM>.

<FIG> is a graph showing a result of measurement, by experiment, of a relation between the ratio of the actual width L2 to the straight line distance width L1 and a strength ratio of the rim section <NUM> in the sound-absorbing material for vehicles <NUM>. Note that in <FIG>, a space between the fixed part <NUM> and the fixed part <NUM> that are provided in the rim section <NUM> is set to <NUM>, and this space of <NUM> is set as a space between fulcrums. Then, in a case where load is applied to the rim section <NUM>, a displacement amount is measured. In this case, a strength at a time when the ratio of the actual width L2 to the straight line distance width L1 is <NUM> is used as a reference (the strength = <NUM>), and the strength ratio of the rim section <NUM> is indicated. Here, it is indicated that when the ratio of the actual width L2 to the straight line distance width L1 is <NUM>, the rim section <NUM> is not bent and is planar.

Therefore, a curve denoted with A in <FIG> shows a relation between the ratio of the actual width L2 to the straight line distance width L1 and the strength of the rim section <NUM>, when the space between the fulcrums (the space between the fixed part <NUM> and the fixed part <NUM>) is set to <NUM>. Furthermore, a curve denoted with B in <FIG> shows a relation between the ratio of the actual width L2 to the straight line distance width L1 and the strength of the rim section <NUM>, when the space between the fulcrums is set to <NUM>. Additionally, a curve denoted with C in <FIG> shows a relation between the ratio of the actual width L2 to the straight line distance width L1 and the strength of the rim section <NUM>, when the space between the fulcrums is set to <NUM>.

As shown in <FIG>, it is confirmed that the rim section <NUM> tends to have the highest strength, when the ratio of the actual width L2 to the straight line distance width L1 is about <NUM>, regardless of a length of the space between the fulcrums (the space between the fixed part <NUM> and the fixed part <NUM>). Consequently, the rim section <NUM> is formed so that the ratio of the actual width L2 to the straight line distance width L1 is larger than <NUM> and smaller than <NUM>.

Next, description will be made as to a position where the sound-absorbing material for vehicles <NUM> is mounted, in the vehicle interior, and sound absorption characteristics of the sound-absorbing material for vehicles <NUM>.

<FIG> is a view illustrating the position where the sound-absorbing material for vehicles is mounted, in the vehicle interior, in accordance with arrangement of the sound-absorbing section. For example, in the sound-absorbing material for vehicles <NUM> shown in <FIG>, the sound-absorbing section <NUM> provided on the almost center of the main body <NUM> is formed to be mounted to the vehicle interior within a range in which a vertical distance Elh downward from a lower surface of a head rest <NUM> of the front seat <NUM> is from <NUM> to <NUM>.

Furthermore, also in a case where the sound-absorbing material for vehicles is provided on an inner side of a door or the like on a rear seat <NUM> side between the front seat <NUM> and the rear seat <NUM>, a sound-absorbing section <NUM> of the sound-absorbing material for vehicles is mounted to the vehicle interior within the range in which the vertical distance Elh downward from the lower surface of the head rest <NUM> of the front seat <NUM> is from <NUM> to <NUM>. Additionally, also in a case where the sound-absorbing material for vehicles is provided on an inner side of a door or the like of the front seat <NUM>, or a surface of a dashboard <NUM> between the dashboard <NUM> and the front seat <NUM>, as shown in <FIG>, each of a sound-absorbing section <NUM> and a sound-absorbing section <NUM> of the sound-absorbing material for vehicles is mounted to the vehicle interior within the range in which the vertical distance Elh downward from the lower surface of the head rest <NUM> of the front seat <NUM> is from <NUM> to <NUM>.

Furthermore, if backrest parts of the front seat <NUM> and the rear seat <NUM> are stood vertically or reclined and inclination of each backrest is changed, for example, in a range from about <NUM> to <NUM> degrees, a position of the head rest <NUM> or a head rest <NUM> varies. Even in this case, the vertical distance Elh is set to be in the range from <NUM> to <NUM>.

Additionally, the sound-absorbing section <NUM> is configured so that an airflow resistance AFR (Ns/m<NUM>) and the vertical distance Elh (m) satisfy Equation (<NUM>) as follows.

Note that the sound-absorbing material for vehicles <NUM> in the present application does not include a dash insulator <NUM> and a carpet <NUM>. This is because the dash insulator <NUM>, provided between a boarding space of the vehicle interior and an engine compartment or the like, is hard for the passenger to see and hence is not provided with the surface <NUM>. That is, the dash insulator is disposed at a position distant from positions of ears and a mouth of a general adult passenger. Also, the carpet <NUM> is disposed at a position distant from the positions of the ears and mouth of the general adult passenger. Specifically, it is considered that the dash insulator <NUM> and the carpet <NUM> have a relatively low degree of influence on clarity in conversation between passengers.

<FIG> is a graph illustrating sound absorption characteristics of members arranged in the vehicle interior. In <FIG>, a curve A shows sound absorption characteristics of the sound-absorbing section <NUM> that are set in a case where the vertical distance Elh is small and the airflow resistance AFR is <NUM> (Ns/m<NUM>). Furthermore, a curve B shows sound absorption characteristics of the sound-absorbing section <NUM> that are set in a case where the vertical distance Elh is large and the airflow resistance AFR is <NUM> (Ns/m<NUM>). Additionally, a curve C shows sound absorption characteristics in a case where an airflow resistance AFR of the carpet <NUM> as a comparative example is <NUM> (Ns/m<NUM>) or more.

As shown in <FIG>, the sound-absorbing section <NUM> is provided so that a sound absorption coefficient at a frequency of <NUM> or more is set to be higher than a sound absorption coefficient at a frequency that is less than <NUM>. Here, this is because it is considered that a frequency band, in which the degree of influence on the clarity in conversation between the passengers is large, is less than <NUM>. Furthermore, it is considered that the frequency band of <NUM> or more includes a large amount of unnecessary sound in the vehicle interior, and hence the sound absorption coefficient is set to be high.

Thus, each of the sound-absorbing section <NUM>, the sound-absorbing section <NUM> and the sound-absorbing section <NUM> is disposed in the vehicle interior so that the vertical distance Elh is in the range from <NUM> to <NUM>, and hence the sound-absorbing section is disposed in a predetermined region below the positions of the ears and mouth of the general adult passenger. Consequently, the sound absorption from the conversation between the passengers can be inhibited by the above described sound absorption characteristics, while another unnecessary sound in the vehicle interior can be absorbed.

Next, modifications of the sound-absorbing material for vehicles <NUM> will be described. <FIG> is a view showing a configuration example of a first modification (a sound-absorbing material for vehicles 1a) of the sound-absorbing material for vehicles <NUM> seen from a back side. Hereinafter, substantially the same configuration is denoted with the same reference sign.

As shown in <FIG>, in the sound-absorbing material for vehicles 1a installed to a vehicle front seat <NUM>, a fastener <NUM> is provided in an end portion of a bent section <NUM>. The fastener <NUM> enables any member or a predetermined member to be detachably attached to each part that forms the sound-absorbing material for vehicles 1a. For example, the fastener <NUM> is configured to replaceably and detachably attach a surface <NUM>.

<FIG> is a view for explaining the further technical background of the present invention and showing a second modification (a sound-absorbing material for vehicles <NUM>) of the sound-absorbing material for vehicles <NUM>. As shown in <FIG>, the sound-absorbing material for vehicles <NUM> is mounted to, for example, a door <NUM> on a rear seat <NUM> side, and is configured to comprise a sound-absorbing section <NUM> shown in <FIG>.

Next, modifications of the sound-absorbing section <NUM> will be described.

<FIG> is a view showing the modifications of the sound-absorbing section <NUM>. <FIG> is a view showing a first modification (a sound-absorbing section 12a) of the sound-absorbing section <NUM>. <FIG> is a view showing a second modification (a sound-absorbing section 12b) of the sound-absorbing section <NUM>.

As shown in <FIG>, the sound-absorbing section 12a includes a configuration where, for example, a third fiber material <NUM>, a foam layer of hard urethane <NUM>, PE powder <NUM> and a surface <NUM> are stacked and integrally formed.

The third fiber material <NUM> is, for example, made of <NUM>/m<NUM> of PET. The hard urethane <NUM> is sandwiched between the third fiber material <NUM> and the surface <NUM>, and has a thickness set to <NUM> or more and <NUM> or less. For example, the thickness of the hard urethane <NUM> is set to <NUM>.

As shown in <FIG>, the sound-absorbing section 12b includes a configuration where, for example, a fourth fiber material <NUM>, a foam layer of soft urethane <NUM>, PE powder <NUM> and a surface <NUM> are stacked and integrally formed.

The fourth fiber material <NUM> is, for example, made of <NUM>/m<NUM> of PET. The soft urethane <NUM> is sandwiched between the fourth fiber material <NUM> and the surface <NUM>, and has a thickness set to <NUM> or more and <NUM> or less. For example, the thickness of the soft urethane <NUM> is set to <NUM>.

Note that each of the sound-absorbing section 12a and the sound-absorbing section 12b comprises urethane as the foam layer having a thickness of <NUM> or more, which is a member other than fiber and in which an airflow resistance has a predetermined value or more. This is because, for example, if the thickness of urethane is from <NUM> to <NUM>, i.e., less than <NUM>, the airflow resistance is small, and influence on acoustic characteristics is small. Note that the foam layer is not limited to urethane, as long as the layer can be formed of a well-known foam material.

<FIG> is a view showing a third modification (a sound-absorbing section 12c) of the sound-absorbing section <NUM>. As shown in <FIG>, the sound-absorbing section 12c includes a configuration where, for example, a fourth fiber material <NUM>, PE powder <NUM> and a surface <NUM> are stacked and integrally formed.

<FIG> is a view showing a fourth modification (a sound-absorbing section 12d) of the sound-absorbing section <NUM>. As shown in <FIG>, the sound-absorbing section 12d includes a configuration where a non-breathable material <NUM> is stacked on a fourth fiber material <NUM> of a sound-absorbing section 12c, on a side opposite to the surface <NUM>. For example, the non-breathable material <NUM> is a non-breathable thin film.

Note that the non-breathable material <NUM> may be provided to the sound-absorbing section 12a, the sound-absorbing section 12b or the sound-absorbing section 12c described above.

Next, description will be made as to characteristics of the first modification to the third modification of the sound-absorbing section <NUM> (the sound-absorbing section 12a, the sound-absorbing section 12b, and the sound-absorbing section 12c).

<FIG> is a table showing the characteristics of the first modification to the third modification of the sound-absorbing section <NUM> (the sound-absorbing section 12a, the sound-absorbing section 12b, and the sound-absorbing section 12c). As shown in <FIG>, the sound-absorbing section 12a has a surface density of <NUM>/m<NUM>, a thickness of <NUM>, and an airflow resistance AFR of <NUM> Ns/m<NUM>. The sound-absorbing section 12b has a surface density of <NUM>/m<NUM>, a thickness of <NUM>, and an airflow resistance AFR of <NUM> Ns/m<NUM>. The sound-absorbing section 12c has a surface density of <NUM>/m<NUM>, a thickness of <NUM>, and an airflow resistance AFR of <NUM> Ns/m<NUM>.

Claim 1:
Vehicle front seat (<NUM>) comprising a sound-absorbing material (<NUM>, 1a, <NUM>), wherein:
- the sound-absorbing material (<NUM>, 1a, <NUM>) is mounted to a back side of the vehicle seat (<NUM>),
- the sound-absorbing material (<NUM>, 1a, <NUM>) comprises a main body (<NUM>) in which at least a fiber material (<NUM>, <NUM>, <NUM>, <NUM>) and a surface material (<NUM>) are integrally formed,
- a sound-absorbing section (<NUM>, 12a - 12d, <NUM>, <NUM>, <NUM>) is formed in at least a part of the main body (<NUM>), and
- the sound-absorbing section (<NUM>, 12a - 12d, <NUM>, <NUM>, <NUM>) is mounted to the back side of the vehicle front seat (<NUM>) within a range in which a vertical distance Elh downward from a lower surface of a head rest of a vehicle front seat (<NUM>) to the sound-absorbing section (<NUM>, 12a - 12d, <NUM>, <NUM>, <NUM>) of the sound-absorbing section (<NUM>, 12a - 12d, <NUM>, <NUM>, <NUM>) is from <NUM> to <NUM>,
characterized in:
- that an airflow resistance AFR determined in units of Ns/m<NUM> and the vertical distance Elh determined in units of m satisfy a relation of: <MAT> and
- that the airflow resistance AFR is set for the sound-absorbing section (<NUM>, 12a- 12d, <NUM>, <NUM>, <NUM>) by having a thickness for the sound-absorbing section (<NUM>, 12a - 12d, <NUM>, <NUM>, <NUM>) which is different from the thickness of other areas of the main body (<NUM>).