Patent Description:
Hitherto, as a cover for an air conditioning device for a vehicle, there is known a cover including an arch-like plate, reinforcing members provided on the outer side of the plate, and a heat insulating material provided on the inner side of the plate (see Patent Literature <NUM>, for example).

On the other hand, a fiber reinforced plastic (FRP) sandwich panel including a foamed material as a core is known to be capable of light-weighting while keeping stiffness and to have excellent heat insulating property (see Patent Literature <NUM>, for example). <CIT> discloses a method for manufacturing a laminated panel by laminating a core material with a curved face and reinforcing fibers.

However, the cover described in Patent Literature <NUM> includes a plate, which is a stainless plate. Moreover, the reinforcing members are angle bars, and therefore a total weight is large. Moreover, the reinforcing members are required to be fixed by welding onto an upper surface of the plate, whereas the heat insulating material is required to be bonded onto a lower surface of the plate. Therefore, there is a problem of low productivity.

In the case of an FRP sandwich panel described in Patent Literature <NUM>, thermal processing or cutting work is required to be performed in advance on a core material in order to obtain a curved shape required for the cover for an air conditioning device for a vehicle. Therefore, productivity is low. Moreover, when a molding die is used, a die having a curved shape, which costs high, is required to be used. Thus, there is a problem in that costs run up.

The present invention has been made to solve the problems described above, and has an object to provide a cover for an air conditioning device for a vehicle, which is capable of light-weighting and improving productivity at low costs, and a method of manufacturing the same.

The invention is defined by the method of claim <NUM>. According to one embodiment of the present disclosure, there is provided a cover for an air conditioning device for a vehicle, the cover including: a core made of a foamed material having heat insulating property; and a surface member for covering entire surfaces of the core, the surface member being made of a fiber reinforced plastic obtained by impregnating fibers with a resin, in which the core is elastically deformed into a curved shape.

Further, according to one embodiment of the present disclosure, there is provided a method of manufacturing a cover for an air conditioning device for a vehicle, the method including the steps of:.

According to the cover for an air conditioning device for a vehicle of one embodiment of the present disclosure, the cover includes the core made of the foamed material having the heat insulating property and the surface member made of the fiber reinforced plastic, which covers the entire surfaces of the core. Therefore, lightweight property is obtained, whereas an additional step of bonding a heat insulating material is not required. Therefore, productivity is improved.

Moreover, the core is elastically deformed into a curved shape. Therefore, as compared to a cover including a core, which is not elastically deformed, that is, a cover including a core, which is subjected to thermal deformation or deformation by cutting work or with a molding die in advance, a repelling force is large with respect to an external force. Thus, a withstand load increases.

Moreover, according to the method of manufacturing the cover for an air conditioning device for a vehicle of one embodiment of the present invention, the core is elastically deformed into a curved shape under its own weight in the shaping step. Therefore, a step of deforming the core into the curved shape by thermal, cutting, or the molding die is not required. Therefore, the productivity is improved at low costs.

Referring to the drawings, embodiments of the present invention are described below. In the drawings, the same or corresponding components and parts are denoted by the same reference symbols.

<FIG> is a plan view illustrating an air conditioning device for a railway vehicle, onto which covers <NUM> and <NUM> for an air conditioning device for a railway vehicle are mounted according to a first embodiment of the present disclosure. In the figure, right halves of the covers <NUM> and <NUM> are cut out.

The air conditioning device for a railway vehicle is mounted onto a ceiling portion of the vehicle, and includes an indoor unit portion <NUM>, which is in communication to a vehicle indoor side, an outdoor unit portion <NUM>, a casing <NUM>, which houses the indoor unit portion <NUM> and the outdoor unit portion <NUM> therein, and an indoor cover <NUM> for covering the indoor unit portion <NUM> and an outdoor cover <NUM> for covering the outdoor unit portion <NUM>, each being exposed to outside air.

Each of the indoor cover <NUM> and the outdoor cover <NUM> is, as illustrated in <FIG>, rectangular, and has a curved shape with a curved surface projecting upward at a curvature of from <NUM>,<NUM> to <NUM>,<NUM>, the curvature being suitably <NUM>,<NUM> in order to maximally using a space from the viewpoint of a vehicle gauge.

The indoor cover <NUM> and the outdoor cover <NUM> cover an air-conditioner main body, which includes the indoor unit portion <NUM> and the outdoor unit portion <NUM>.

The indoor unit portion <NUM> includes an indoor fan <NUM> and an indoor heat exchanger <NUM>.

The outdoor unit portion <NUM> includes an outdoor fan <NUM>, an outdoor heat exchanger <NUM>, and a compressor <NUM>.

<FIG> is a sectional view taken along the line III-III of <FIG> as viewed from the direction of the arrows.

The outdoor cover <NUM> is manufactured by Vacuum Assisted Resin Transfer Molding (VaRTM), and includes a core <NUM> made of a foamed material having heat insulating property and closed cells, a surface member <NUM> made of a fiber reinforced plastic (FRP; hereinafter referred to as "FRP"), which covers the entire surfaces of the core <NUM> elastically deformed into a curved shape, a resin diffusion medium <NUM> interposed between an upper surface of the core <NUM> and the surface member <NUM>, and a gel coat <NUM>, which covers an upper surface of the surface member <NUM>, all of which are integrated with each other.

The FRP is obtained by impregnating carbon reinforcing fibers, which is excellent in lightness, mechanical properties, thermal properties, optical properties, and a degree of freedom of a molding method, with a vinyl ester resin as a base material resin.

Note that, as reinforcing fibers, there may be used, for example, glass fibers, aramid fibers, Kevlar fibers, boron fibers, or alumina fibers.

In addition, as the base material resin, there may be used, for example, a thermosetting resin such as an epoxy resin, an unsaturated polyester resin, a furan resin, or a polyurethane resin instead of the vinyl ester resin.

The fibers may be, for example, staple fibers or filament fibers. The filament fibers are used from the viewpoint of mechanical properties, and textile fibers are used as a form of the fibers.

The core <NUM> has a Young's modulus of from <NUM> MPa to <NUM> MPa and heat insulating property above the flame-retardance acceptance criteria defined in the Material Combustion Test for Vehicles of Railroad (Article <NUM> of "Technical Regulatory Standards on Japanese Railways" (Ordinance No. <NUM> prescribed by the Ministry of Land, Infrastructure, Transport and Tourism, December <NUM>, <NUM>) and is made of a foamed material including closed cells, which is a thermosetting resin. Specifically, the core <NUM> is made of a phenolic-resin foamed material.

A thickness of the core <NUM> is set so that required heat insulating property and bending stiffness are obtained, and is suitably <NUM> to <NUM>, more preferably <NUM>. The thickness equal to or larger than <NUM> is not desired because a volume occupied by the outdoor cover <NUM> becomes larger. With the thickness equal to or smaller than <NUM>, the stiffness required as the outdoor cover <NUM> is not obtained.

As the Young's modulus of the core <NUM>, there is adopted such a Young's modulus that deformation at an atmospheric pressure that the core undergoes in a manufacturing step described later is suppressed within an allowable range, and that the core <NUM> is deformed at a predetermined curvature.

The deformation of the core <NUM> into the curved shape at the predetermined curvature is happening under its own weight at room temperature.

Specifically, a Young's modulus E is set within the range of a value obtained by the following formula using a curvature R of a predetermined shape, a length <NUM>, a thickness t, a width b, a density ρ, an atmospheric pressure P, and a dimensional tolerance f. <NUM>] <MAT>.

Formula (<NUM>) is derived based on the fact that a deflection amount obtained from Formula (<NUM>):
[Math. <NUM>] <MAT>.

By substituting t = <NUM>, f = <NUM> (fine-degree general dimensional tolerance), R = <NUM>,<NUM>, <NUM> = <NUM>,<NUM>, ρ = <NUM>/mm<NUM> into Formula (<NUM>) as the most preferred conditions, the best mode can be realized with the Young's modulus E of from <NUM> MPa to <NUM> MPa.

<FIG> shows the results of a test for whether or not the core <NUM> with a thickness of <NUM>, which is placed in a molding die having a curvature of <NUM>,<NUM> and is deformed under its own weight, is actually deformed to lie along the molding die and the results of a test for whether or not a plate-thickness change occurring when the core <NUM> covered with a bagging film is subjected to vacuuming is within the fine-degree general dimensional tolerance of <NUM>, the results being marked with circles and crosses.

From the above-mentioned results, it is verified that the core <NUM> having the Young's modulus E of from <NUM> MPa to <NUM> MPa is deformed to lie along the curvature of <NUM>,<NUM> under its own weight without undergoing a thermal processing or cutting work step and that the deformation at the atmospheric pressure can be suppressed within the fine-degree general dimensional tolerance.

The resin diffusion medium <NUM> includes a net-like flow channel formed therein. A vinyl ester resin, which is a matrix resin, flows through the flow channel so that carbon reinforcing fibers are impregnated therewith.

Carbon fibers are used as a material for the resin diffusion medium <NUM> from thermal and mechanical viewpoints.

Note that, the material for the resin diffusion medium <NUM> may be, for example, glass fibers, aramid fibers, Kevlar fibers, boron fibers, alumina fibers, a thermosetting resin such as an epoxy resin, an unsaturated polyester resin, a vinyl ester resin, a furan resin, or a polyurethane resin, or a thermoplastic resin such as a nylon, a PBT, or a ABS.

As the gel coat <NUM>, an unsaturated polyester resin, which has flame retardance provided by bromination, is used from the viewpoint of the flame retardance so as to prevent the interior of the outdoor cover <NUM> from being adversely affected by light, water, heat, or the like.

Note that, a material for the gel coat <NUM> may be, for example, a thermosetting resin such as an epoxy resin, a vinyl ester resin, a furan resin, or a polyurethane resin.

Note that, a configuration of the indoor cover <NUM> is the same as that of the outdoor cover <NUM>, and the description thereof is herein omitted.

Next, a method of manufacturing the outdoor cover <NUM> for the air conditioning device for a railway vehicle according to the first embodiment of the present invention is described.

First, onto a molding die <NUM>, which is subjected to demolding processing with a Teflon (trademark) coating, a gel coat resin is applied by using a spray gun to form the gel coat <NUM>.

Next, a predetermined number of layers of textile fibers <NUM> are laminated in a predetermined direction on the gel coat <NUM>.

Thereafter, the resin diffusion medium <NUM> is laminated thereon. Although the resin diffusion medium <NUM> may be laminated between the textile fibers <NUM> and the gel coat <NUM> or between the textile fibers, the resin diffusion medium <NUM> is provided between the textile fibers <NUM> and the core <NUM> from the viewpoint of design.

Next, the core <NUM> is placed on the resin diffusion medium <NUM>.

In this manner, in a shaping step in which the textile fibers <NUM>, the resin diffusion medium <NUM>, and the core <NUM> are shaped sequentially on the molding die <NUM>, the core <NUM> is deformed under its own weight so as to lie along the molding die <NUM> having the curvature of <NUM>,<NUM>, as illustrated in <FIG>.

Next, as illustrated in <FIG>, a predetermined number of layers of the textile fibers <NUM> are laminated in a predetermined direction.

A peel ply <NUM> is laminated thereon. Then, the resin diffusion medium <NUM> is provided thereon.

Next, an intake port <NUM> for air to a vacuum pump and an injection port <NUM> for a resin to be injected from a resin tank (not shown) are mounted to the molding die <NUM>. The entirety is covered with a bagging film <NUM>. A periphery of the bagging film <NUM> is bonded to the molding die <NUM> with a sealant <NUM> so as to prevent air leakage.

Thereafter, the interior including the textile fibers <NUM>, which is covered with the bagging film <NUM>, is placed into a vacuum state by using the vacuum pump. Then, a valve is released to inject the resin.

The interior covered with the bagging film <NUM> is placed into the vacuum state. The resin passes through the two resin diffusion media <NUM> to be diffused in all the fibers while the textile fibers <NUM> are impregnated in a thickness direction (impregnation step).

After the impregnation step, the valve is closed to cure the resin.

After the resin is cured, the bagging film <NUM>, one of the resin diffusion media <NUM>, which is located on the upper side, and the peel ply <NUM> are removed. Finally, the outdoor cover <NUM> for the air conditioning device for a railway vehicle, in which the entire surfaces of the core <NUM> are covered with the surface member <NUM> made of the FRP, is demolded from the molding die <NUM>.

Note that, the indoor cover <NUM> is also manufactured by the same method as that for the outdoor cover <NUM>.

As described above, each of the covers <NUM> and <NUM> for the air conditioning device for a railway vehicle according to this embodiment includes the core <NUM> made of the foamed material having the heat insulating property and the surface member <NUM> made of the FRP, in which the fibers are impregnated with the resin, for covering the entire surfaces of the core <NUM>. Therefore, lightweight property is obtained, whereas an additional step of bonding a heat insulating material is not required. Thus, productivity is improved.

Moreover, the core <NUM> is deformed into the curved shape by the elastic deformation under its own weight. Therefore, as compared to a cover including a core, which is not elastically deformed, that is, a cover including a core, which is subjected to thermal deformation or deformation by cutting work or with a molding die in advance, the covers have a large repellant force with respect to the external force. Therefore, their withstand load increases.

Moreover, the core <NUM> is made of the foamed material and includes the closed cells, and hence the interior of the core <NUM> is not impregnated with the resin. Thus, for manufacturing the covers <NUM> and <NUM>, a vacuum impregnation molding method can be employed.

Moreover, the core <NUM> is made of the formed material including the closed cells, which has the Young's modulus of from <NUM> MPa to <NUM> MPa and the thickness of from <NUM> to <NUM>. An intermediate portion of the core <NUM> is flexurally deformed in a state in which the core <NUM> is supported at two points corresponding to both end portions before being covered with the surface member <NUM>. Therefore, each of the covers <NUM> and <NUM> can realize the curved surface at the curvature of from <NUM>,<NUM> to <NUM>,<NUM> under its own weight. Thus, the thermal processing or cutting work is not required, thereby improving the productivity.

Moreover, the fibers are carbon fibers having high specific strength and specific stiffness. Thus, the covers <NUM> and <NUM> can be light-weighted.

Moreover, the surface member <NUM> and the core <NUM> are above the flame-retardance acceptance criteria in the Material Combustion Test for Vehicles of Railroad. Thus, for the covers <NUM> and <NUM>, the flame retardance for railway vehicles can be ensured.

Moreover, the core <NUM> is made of a phenolic resin, which is a thermosetting resin. Therefore, the covers <NUM> and <NUM> excellent in mechanical properties and heat resistance can be obtained.

Further, according to the method of manufacturing the covers <NUM> and <NUM> for the air conditioning device for a vehicle according to this embodiment, for the core <NUM> made of the foamed material including the closed cells, the interior of the core <NUM> is not impregnated with the resin when the covers <NUM> and <NUM> are manufactured by the vacuum impregnation molding method.

Moreover, in the shaping step of shaping the core <NUM> on the molding die <NUM>, the core <NUM> is deformed to be curved under its own weight at room temperature. Thus, for the deformation of the core <NUM>, a thermal processing or cutting step is not required. As a result, the productivity of the covers <NUM> and <NUM> is improved. Moreover, the formation of the curved shape is achieved without using a molding die having a curved shape, which costs high. Thus, low-cost production is achieved.

Claim 1:
A method of manufacturing a cover for an air conditioning device for a vehicle, which is configured to cover an air-conditioner main body mounted on a ceiling portion of the vehicle, the cover comprising:
- - a core (<NUM>) made of a foamed material having heat insulating property; and
- - a surface member (<NUM>) for covering entire surfaces of the core (<NUM>), the surface member (<NUM>) being made of a fiber reinforced plastic obtained by impregnating fibers with a resin,
the method comprising the steps of:
- - shaping the core (<NUM>) comprising closed cells and the fibers by flexing an intermediate portion of the core (<NUM>) to be elastically deformed in a state in which the core (<NUM>) is supported at two points corresponding to both end portions of the core (<NUM>) on a molding die (<NUM>) having a curved shape;
- - impregnating the fibers with the resin by injecting the resin into a sealed space formed between the molding die (<NUM>) and the core (<NUM>) by vacuuming; and
- - demolding the cover from the molding die (<NUM>) after the resin is cured, wherein the shaping comprises elastically deforming the core (<NUM>) under own weight at room temperature.