Patent Description:
There have conventionally been known flavor inhalers for inhaling flavor without burning a material (e.g., PTL <NUM> related to the preamble of claim <NUM>, and PTL <NUM>). Such flavor inhalers may cause a problem with safety since users may suffer from burn injuries when excessive heat for heating a flavor source transfers to users via inhalers. Therefore, there has been a demand for measures to prevent heat from easily transferring to users.

An object of the present invention is to provide a heating assembly that enables provision of a flavor inhaler having excellent heat insulation performance for preventing heat from transferring to the outside.

The present inventors found that the aforementioned object can be achieved by using a member having particular heat insulation properties, and thus completed the present invention. More specifically, the aforementioned object can be achieved by the following invention.

The present invention can provide a heating assembly that enables formation of a flavor inhaler having excellent heat insulation performance for preventing heat from transferring to the outside.

The "flavor inhaler" refers to an apparatus for generating a flavor by heating a flavor-generating article. The "flavor-generating article" refers to an article that enables generation of a flavor or inhalation of a favor and which comprises a flavor-generating substrate. The "flavor-generating substrate" refers to a substrate that is configured to generate a flavor and which comprises an aerosol source.

<FIG> illustrates one embodiment of a flavor inhaler. As shown in <FIG>, a flavor inhaler <NUM> has an opening 12a for inserting a smoking article <NUM> which is one embodiment of a flavor-generating article. <FIG> illustrates a cross-sectional view taken along arrow <NUM>-<NUM> in <FIG>. As shown in this figure, the opening 12a communicates with the heating assembly <NUM>, and the smoking article <NUM> is heated in the heating assembly <NUM>. Hereunder, the heating assembly will be first described, and then the details of the flavor inhaler will be described.

As shown in <FIG>, the heating assembly <NUM> is disposed in a heating section <NUM> of the flavor inhaler <NUM>, and has a cylindrical shape as a whole. The heating assembly <NUM> is configured to house part of the smoking article <NUM> within its interior, and has a function of defining an air flow passage for supplying air to the smoking article <NUM> and a function of heating the smoking article <NUM> from its outer periphery.

<FIG> depicts a lateral view of one embodiment of the heating assembly <NUM>. The heating assembly <NUM> comprises an outer cylinder <NUM>, a top cap <NUM>, and a bottom cap <NUM>. Though not shown in this figure, an inner cylinder is disposed in the interior of the outer cylinder <NUM>. The inner cylinder may be covered by a heat-shrinkable tube <NUM>. In this case, the heat-shrinkable tube may extend so as to cover part of the top cap <NUM> or the bottom cap <NUM>.

Next, the structure of the heating assembly <NUM> will be described by reference to <FIG> depicts an enlarged cross-sectional view of the heating assembly <NUM>. In this figure, <NUM> represents an inner cylinder, <NUM> represents an outer cylinder, <NUM> represents a sealing member, 47t represents a sealing member made of a thermally curable resin, 47p represents a sealing member made of a photocurable resin, <NUM> represents a heating member, <NUM> represents a closed space, <NUM> represents a heat insulation material, <NUM> represents a washer, 42a represents a first opening, and 42b represents a second opening.

The position at which the heating member <NUM> is disposed is not limited. When, like in this embodiment, the inner cylinder <NUM> and the heating member <NUM> are in proximity to, or in contact with, each other, it is preferred that the inner cylinder <NUM> should have excellent heat conductivity since it acts to transfer heat generated from the heating member <NUM> to a smoking article <NUM>. The inner cylinder <NUM> preferably has a heat conductivity of from <NUM> to <NUM> W/m/K, more preferably from <NUM> to <NUM> W/m/K. From this viewpoint, the material used to make the inner cylinder <NUM> is preferably a metal, more preferably stainless steel. The material used to make the outer cylinder <NUM> is not limited, but is preferably a metal, more preferably stainless steel, from the viewpoints of ease of handling, durability, and the like. The inner diameter of the inner cylinder <NUM> depends on the dimension of the smoking article <NUM>. In one embodiment, the inner diameter of the inner cylinder <NUM> is the same as that of part of a bottom cap <NUM> as described later. The distance between the inner cylinder <NUM> and the outer cylinder <NUM> is preferably in the range of from <NUM> to <NUM>, more preferably from <NUM> to <NUM>. The length of the inner cylinder <NUM> will be described later.

As mentioned above, the position at which the heating member <NUM> is disposed is not limited. As shown in this embodiment, the heating member <NUM> may be disposed on a surface of the inner cylinder <NUM> which faces toward the outer cylinder <NUM> and heat the smoking article <NUM> inserted into the inner cylinder <NUM>. Also, the heating member <NUM> may be installed independently from the inner cylinder <NUM>, the outer cylinder <NUM>, and the closed space <NUM>. For example, it is also possible that a cylindrical member into which the smoking article <NUM> can be inserted may be disposed in the inside of the inner cylinder and the heating member <NUM> may be installed on a surface of said cylindrical member. The heating member <NUM> is able to generate heat at a temperature of preferably not more than <NUM>, more preferably not more than <NUM>, particularly preferably not more than <NUM>. The heating member <NUM> is preferably a film heater comprising a heat-generating resistance element and a polymeric layer made of a polyimide or the like. Though not shown in the figure, the heating member <NUM> can be fixed on the inner cylinder <NUM> using a heat-shrinkable tube. From the viewpoint of enhancement of a heat insulation effect, it is preferred that the heating member <NUM> should not be in contact with the sealing members <NUM>.

Since the closed space <NUM> can have vacuum inside or contain a gas such as air inside, it has heat insulation capability and prevents heat generated from the heating member <NUM> from easily transferring to the outer cylinder <NUM>. However, the present inventors found that heat generated from the heating member <NUM> easily transfers via the sealing members <NUM> acting as heat bridges to the outer cylinder <NUM>. Thus, the present invention solves the problem with this heat transfer by ensuring that the heat conductivity of the heat bridges is lower than that of the inner cylinder <NUM>. As a result, an increase in the temperature of a housing <NUM> can be prevented so that users can use the flavor inhaler <NUM> in a comfortable and safe manner. It is preferred that the heat conductivity of the sealing members <NUM> should be lower by not less than <NUM> W/m/K than that of the inner cylinder <NUM>. To be specific, the heat conductivity of the sealing members <NUM> is preferably in the range of from <NUM> to <NUM> W/m/K, more preferably from <NUM> to <NUM> W/m/K.

The sealing members <NUM> preferably comprise a thermally curable resin or a photocurable resin. The "thermally curable resin" refers to a cured product formed of a thermally curable monomer that reacts at room temperature or by heating to form a crosslinked structure, and examples thereof include acrylate resins, epoxy resins, urethane resins, phenol resins, silicone resins, and the like. Among them, acrylate resins are preferred from the viewpoints of curability and ease of handling. Also, from the viewpoints of strength and the like, the thermally curable monomer preferably has a molecular weight of approximately from <NUM> to <NUM>, more preferably approximately from <NUM> to <NUM>.

The "photocurable resin" refers to a cured product formed of a photocurable monomer that forms a crosslinked structure by exposure to light, and is preferably a UV-curable resin that cures by exposure to UV light. Examples of the photocurable resin include, but are not limited to, radically polymerizable acrylate resins and cationically polymerizable epoxy resins. From the viewpoints of curability and ease of handling, the photocurable resin is preferably a radically polymerizable acrylate resin, more preferably an epoxy acrylate resin. Also, from the viewpoints of strength and the like, the photocurable monomer preferably has a molecular weight of approximately from <NUM> to <NUM>. In addition, curable resins that combine both thermal curability and photocurability may also be used.

The thermally curable resin and the photocurable resin preferably have a Tg (glass-transition temperature) of not more than <NUM>, more preferably not more than <NUM>, particularly preferably not more than <NUM>. Since the thermally curable resin and the photocurable resin have such a preferred Tg as mentioned above, when the heating member <NUM> generates heat, the temperature rises at that portion of the sealing members <NUM> which is close to the heating member <NUM>. When the Tg of the curable resins is low, the resins become flexible but do not melt due to heating of the heating member <NUM> so that stress caused by thermal expansion of the inner cylinder <NUM>, or by thermal expansion of the inner cylinder and the outer cylinder can be relaxed. The curable resins may also contain a known filler such as silica or glass particles.

From the viewpoints of strength and the like, the sealing members <NUM> preferably have a thickness of from <NUM> to <NUM>, more preferably from <NUM> to <NUM>. The sealing members <NUM> preferably have a multi-layer structure comprising a plurality of layers stacked in the longitudinal direction of the heating assembly, wherein the innermost layer more preferably comprises a photocurable resin. Although the closed space <NUM> has heat insulation capability as mentioned above, the closed space <NUM> is preferably provided with a heat insulation material <NUM> in order to enhance a heat insulation effect. In such a case, when a sealing member is made using a photocurable resin, which is formed by a rapid curing reaction, the heat insulation material <NUM> can be easily filled in the closed space <NUM>. Further, by stacking a sealing member made of a thermally curable resin on the photocurable resin, the strength of the sealing member can be enhanced and, at the same time, the heat insulation property of the sealing member can be increased. In some cases, photocurable resins have a lower heat conductivity than thermally curable resins, and thermally curable resins are more likely to contain voids than photocurable resins. Therefore, by stacking a sealing member made of a thermally curable resin on a sealing member made of a photocurable resin, both higher heat conductivity and higher reliability can be achieved.

<FIG> illustrates an embodiment in which spaces at both ends of the inner cylinder <NUM> and the outer cylinder <NUM> are sealed by the aforementioned curable resins. It is preferred that at least one of spaces at the ends of the inner cylinder <NUM> and the outer cylinder <NUM> should be sealed by the aforementioned curable resins. The outer cylinder <NUM> may be provided with a hole <NUM>. The purpose of this is to prevent voids from forming in the sealing members <NUM> due to expansion of air in the closed space upon curing of the sealing members <NUM> by heating. The hole <NUM> may be sealed with a known sealing after curing.

The heat insulation material <NUM> is preferably in a granular form. The average particle size, D50, of the heat insulation material <NUM> is preferably in the range of from <NUM> to <NUM>, more preferably from <NUM> to <NUM>. Average particle size can be determined by image analysis. Though only part of the heat insulation material <NUM> is shown in the figure for the sake of clarity, it is preferred that an adequate amount of the heat insulation material <NUM> should be filled in the closed space <NUM>. When a granular heat insulation material is densely filled in the closed space <NUM> in this manner, the heat insulation material is more likely to spill over the closed space. However, in the present invention, the heat insulation material can be filled smoothly since the sealing members <NUM> can be cured rapidly. Therefore, this invention has more advantageous effects when a granular heat insulation material is used. Examples of the granular heat insulation material include an aerogel. The "aerogel" is a porous material and can be exemplified by silicon aerogel and carbon aerogel. The amount of an aerogel filled varies with the density of the aerogel and the volume of the closed space <NUM>, but in one embodiment is in the range of approximately from <NUM> to <NUM>.

It is preferred that the sealing members should not contain free components. Due to the absence of free components in the sealing members, penetration of free components into the closed space <NUM> or the heat insulation material <NUM> can be prevented so that advantageous heat insulation performance can be sustained. It is preferred that isolation members that isolate at least part of the sealing members <NUM> from the closed space <NUM> should be disposed in the closed space, since even if any free components are are released from the sealing member, penetration of said components can be prevented by the isolation members. Further, when the sealing members <NUM> come into direct contact with the heat insulation material <NUM>, such as aerogel, the sealing member <NUM> or free components released therefrom may penetrate into the heat insulation material <NUM>, resulting in inadequate heat insulation performance. However, by arranging the aforementioned isolation members in the closed space <NUM>, such penetration can be prevented. The material used to make the isolation members is not limited, but is preferably a metal, a resin, or ceramic, more preferably stainless steel. The isolation members preferably extend in a circumferential direction. To be specific, the isolation members are preferably ring-shaped members such as washers <NUM>. In order to avoid the isolation members from acting as heat bridges, it is preferred that the isolation members should be disposed so as to isolate at least part of the sealing members <NUM> from the closed space <NUM>. In other words, it is preferred that the isolation members should be disposed at a distance from at least one of the inner cylinder <NUM> or the outer cylinder <NUM>.

When the sealing members <NUM> are composed of a plurality of layers as mentioned above, it is preferred that a photocurable resin layer having a rapid curing property should be used as the innermost layer, and a thermally curable resin layer should be provided on the photocurable resin layer to thereby achieve secure sealing. Therefore, from the viewpoint of achieving a higher curing rate, it is preferred that the photocurable resin layer should be relatively thin and the thermally curable resin layer should be relatively thick. Thus, the ratio of the volume of the thermally curable resin layer to that of the photocurable resin layer is preferably in the range of from <NUM> to <NUM>, more preferably from <NUM> to <NUM>. The ratio of the average thickness of the thermally curable resin layer to that of the photocurable resin layer is preferably in the range of from <NUM> to <NUM>, more preferably from <NUM> to <NUM>. In the embodiment where the isolation members are disposed, it is preferred that the photocurable resin layer and the thermally curable resin layer should be stacked in this order on each of the isolation members, and besides that the different layers should satisfy the aforementioned relationships. Further, in this embodiment, it is preferred that both of the side surfaces and one of the principal surfaces of each of the isolation members should be covered by the photocurable resin layer so as not to ensure that the isolation members do not come into contact with the inner cylinder <NUM> or the outer cylinder <NUM> (refer to the panel in a dotted circle in <FIG>). In other words, in the direction from the inner cylinder <NUM> toward the outer cylinder <NUM> in the heating assembly <NUM>, the isolation member and a first photocurable resin are preferably disposed in this order, and a first photocurable resin, the isolation member, and a second photocurable resin are more preferably disposed in this order. Additionally, in this embodiment, the first photocurable resin and the second photocurable resin may be of the same type or of different types, but these resins are preferably of the same type from the viewpoint of ease of production. Also in this embodiment, it is preferred that the different layers should satisfy the aforementioned relationships. To be specific, the ratio of the volume of the thermally curable resin layer to that of the layer composed of the first and second photocurable resins is preferably in the range of from <NUM> to <NUM>, more preferably from <NUM> to <NUM>. The ratio of the average thickness of the thermally curable resin layer to that of the layer composed of the first and second photocurable resins is preferably in the range of from <NUM> to <NUM>, more preferably from <NUM> to <NUM>. When no second photocurable resin is used, the volume ratio and the thickness ratio of the aforementioned layers can be determined on the basis of the volume and thickness of a layer formed of the first photocurable resin alone. The average thickness of the photocurable resin layer is an average value of the thicknesses of the layer composed of the first and second photocurable resins, excluding the isolation member, in the longitudinal direction of the heating assembly <NUM>.

The heating assembly <NUM> has a top cap <NUM> and a bottom cap <NUM>. The top cap <NUM> and the bottom cap <NUM> can be formed from, for example, a known resin. The top cap <NUM> is a cylindrical member having an internal space communicating with a first opening 42a of the inner cylinder <NUM>, and is configured so that a smoking article <NUM> can be inserted thereinto.

As shown in <FIG> and <FIG>, the top cap <NUM> is connected to the first opening 42a of the inner cylinder <NUM>. The bottom cap <NUM> is an elongated cylindrical member connected to a second opening 42b of the inner cylinder <NUM>. In <FIG> and <FIG>, air flows from the bottom to the top of the panel, and therefore, the bottom and top of the panel are called "upstream" and "downstream", respectively. An internal flow passage is formed which introduces air from the downstream end 50a of the bottom cap <NUM> toward the second opening 42b of the inner cylinder <NUM>. In this embodiment, the heating assembly <NUM> includes the top cap <NUM> and the bottom cap <NUM> between the inner cylinder <NUM> and the sealing members <NUM>. Therefore, the sealability of the internal flow passage is increased, thereby preventing air from leaking from the internal flow passage.

The inner diameter of the bottom cap <NUM> can be constant from the downstream end 50a to the upstream end 50b. It is also acceptable that the inner surface of the bottom cap <NUM> is formed in a tapered shape so that the inner diameter of the bottom cap <NUM> becomes gradually larger from the downstream end 50a toward the upstream end 50b. When the maximum inner diameter of the bottom cap <NUM> is defined as Smax, and the maximum outer diameter of the smoking article <NUM> is defined as Sc, the ratio of Sc to Smax (Sc/Smax) is, for example, in the range of from <NUM> to <NUM>, preferably from <NUM> to <NUM>. When the ratio of the maximum outer diameter of the smoking article <NUM> to the maximum inner diameter of the bottom cap <NUM> falls within the aforementioned range, adequate air flow passage <NUM> can be ensured while an end of the smoking article <NUM> is securely held by an engaging part 50d of the bottom cap <NUM>.

The heating assembly is preferably produced through the following steps.

Step <NUM>: Providing a double cylinder having an inner cylinder disposed inside an outer cylinder.

Step <NUM>: Sealing a space between one end of the inner cylinder and one end of the outer cylinder, which is located on the same side as said one end of the inner cylinder, with a first sealing member having lower heat conductivity than the inner cylinder.

Step <NUM>: Sealing a space between opening ends of the inner cylinder and the outer cylinder with a second sealing member having lower heat conductivity than the inner cylinder.

Step <NUM> can be carried out by, for example, attaching a film heater serving as a heating member <NUM> on the outer peripheral surface of the inner cylinder <NUM> and arranging the outer cylinder <NUM> outside the inner cylinder <NUM>.

The first sealing member used at step <NUM> may be of a different type from, or of the same type as, the second sealing member. In the former case, the first sealing member can be made of any type of material, such as thermoplastic resin or ceramic. When the top cap <NUM> or the bottom cap <NUM> is attached in advance to the inner cylinder <NUM>, it is easy to identify the position of sealing with the first sealing member. This effect also applies at step <NUM>. After the sealing with the first sealing member, an isolation member such as washer may be disposed on the first sealing member.

The second sealing member used at step <NUM> is preferably made of a photocurable resin. This is because photocurable monomers are able to cure rapidly and thus are satisfactory in workability. At an interval between steps <NUM> and <NUM>, an aerogel or the like, serving as a heat insulation material <NUM>, may be filled in a space formed by the inner cylinder, the outer cylinder, and the first sealing member. In this embodiment, when a photocurable resin is used as the second sealing member, the heat insulation material <NUM> can be densely filled as mentioned above. Further, in this embodiment, before step <NUM>, an isolation member such as washer may be disposed on a layer filled with the heat insulation material <NUM>. Furthermore, by arranging a thermally curable resin layer on the photocurable resin layer, more secure sealing can be achieved, resulting in enhanced product reliability.

Next, the overall structure of the flavor inhaler will be described. As shown in <FIG>, the flavor inhaler <NUM> has a top housing 11A, a bottom housing 11B, a cover <NUM>, a switch <NUM>, and a lid <NUM>. The top housing 11A and the bottom housing 11B are connected to each other to constitute the outermost housing <NUM> of the flavor inhaler <NUM>. The housing <NUM> is of a size that fits in a user's hand. When a user uses the flavor inhaler <NUM>, s/he can inhale flavor while holding the flavor inhaler <NUM> by hand.

As shown in <FIG>, the cover <NUM> has an opening 12a into which the smoking article <NUM> can be inserted. The lid <NUM> is configured so that it can move between a first position at which the opening 12a is closed and a second position at which the opening 12a is opened, along a surface of the cover <NUM>. The switch <NUM> is used to turn on and off the flavor inhaler <NUM>. For example, when a user operates the switch <NUM> while the smoking article <NUM> is inserted into the opening 12a as shown in <FIG>, power is supplied to a heating member (not shown) from a battery (not shown) so that the smoking article <NUM> can be heated without burning. When the smoking article <NUM> is heated, an aerosol evaporates from an aerosol source contained in the smoking article <NUM> to incorporate the flavor of a flavor source in the aerosol. The user can inhale the flavor-containing aerosol by sucking on a portion of the smoking article <NUM> which protrudes from the flavor inhaler <NUM> (see <FIG>). In the present invention, the longitudinal direction of the flavor inhaler <NUM> refers to a direction in which the smoking article <NUM> is inserted into the opening 12a.

Next, the internal structure of the flavor inhaler <NUM> will be described. <FIG> depicts a cross-sectional view taken along arrow <NUM>-<NUM> in <FIG>. As shown in <FIG>, the flavor inhaler <NUM> has a power section <NUM>, a circuit section <NUM>, and a heating section <NUM> in an interior space of the housing <NUM>. The circuit section <NUM> has a first circuit board <NUM>, and a second circuit board <NUM> electrically connected to the first circuit board <NUM>. The first circuit board <NUM> is disposed, for example, to extend in the longitudinal direction as shown in the figure. Therefore, the power section <NUM> and the heating section <NUM> are partitioned by the first circuit board <NUM>. As a consequence, heat generated in the heating section <NUM> is prevented from transferring to the power section <NUM>.

The power section <NUM> has a powder source <NUM> electrically connected to the first circuit board <NUM> and the second circuit board <NUM>. The power source <NUM> can be, for example, a rechargeable or non-rechargeable battery.

The heating section <NUM> includes the heating assembly <NUM> as described above. The bottom housing 11B has a ventilation hole <NUM> formed thereon to alloy air to flow into the interior of the heating assembly <NUM>. To be specific, the ventilation hole <NUM> is in fluid communication with the upstream end of the heating assembly <NUM>. The downstream end of the heating assembly <NUM> is in fluid communication with the opening 12a as shown in <FIG>.

When a user sucks on a portion of the smoking article <NUM> which protrudes from the flavor inhaler <NUM> while the smoking article <NUM> is inserted from the opening 12a into the flavor inhaler <NUM> as shown in <FIG>, air flows from the ventilation hole <NUM> into the interior of the heating assembly <NUM>. The introduced air passes through the interior of the heating assembly <NUM> and reaches the interior of the user's mouth together with an aerosol generated from the smoking article <NUM>.

In the present invention, since particular types of sealing members are used in the heating assembly <NUM>, heat is difficult to transfer to the housing <NUM>, so that users can use the flavor inhaler in a comfortable and safe manner.

The following will describe the smoking article <NUM> which is a preferred embodiment of a flavor-generating article. <FIG> depicts a cross-sectional view of the smoking article <NUM>. In an embodiment shown in <FIG>, the smoking article <NUM> has a substrate section 110A that includes a filling <NUM> (which is one example of a flavor-generating substrate) and a first wrapping paper <NUM> which is wrapped around the filling <NUM>, and a mouthpiece section 110B which forms an end opposite to the substrate section 110A. The substrate section 110A and the mouthpiece section 110B are connected by a second wrapping paper <NUM> which is different from the first wrapping paper <NUM>. However, the substrate section 110A and the mouthpiece section 110B can also be connected using the first wrapping paper <NUM> alone without using the second wrapping paper <NUM>.

In <FIG>, the mouthpiece section 110B has a paper pipe <NUM>, a filter <NUM>, and a hollow segment <NUM> disposed between the paper tube <NUM> and the filter <NUM>. The hollow segment <NUM> is composed of, for example, a filling layer having one or more hollow channels, and a plug wrapper which covers the filling layer.

The mouthpiece section 110B shown in <FIG> is composed of three segments, but, in this embodiment, the mouthpiece section 110B may be composed of one or two segments or may be composed of four or more segments.

In the embodiment shown in <FIG>, the longitudinal length of the smoking article <NUM> is preferably in the range of from <NUM> to <NUM>, more preferably from <NUM> to <NUM>, still more preferably from <NUM> to <NUM>. The circumference of the smoking article <NUM> is preferably in the range of from <NUM> to <NUM>, more preferably from <NUM> to <NUM>, still more preferably from <NUM> to <NUM>. In the smoking article <NUM>, the substrate section 110A can have a length of <NUM>, the first wrapping paper <NUM> can have a length of <NUM>, the hollow segment <NUM> can have a length of <NUM>, and the filter <NUM> can have a length of <NUM>. However, the lengths of these individual segments can be changed, as appropriate, depending on the suitability for production, the required quality, and the like.

In this embodiment, the filling <NUM> in the smoking article <NUM> can contain an aerosol source which generates an aerosol upon heating at a specified temperature. The type of the aerosol source is not particularly limited, and can be selected from extracts from various natural products or constituents thereof depending on the intended use. Examples of the aerosol source include, but are not limited to, glycerol, propylene glycol, triacetin, <NUM>,<NUM>-butanediol, and mixtures thereof. The content of the aerosol source in the filling <NUM> is not particularly limited, and is generally not less than <NUM> wt. %, preferably not less than <NUM> wt. %, and is generally not more than <NUM> wt. %, preferably not more than <NUM> wt. %, from the viewpoints of generation of an adequate amount of aerosol and impartation of good smoking flavor.

In this embodiment, the filling <NUM> of the smoking article <NUM> can contain a tobacco shred as a flavor source. The material used to make a tobacco shred is not particularly limited, and any known materials such as lamina and midrib can be used. The content of the filling <NUM> in a smoking article <NUM> with a circumference of <NUM> and a length of <NUM> is in the range of, for example, from <NUM> to <NUM>, preferably from <NUM> to <NUM>. The water content in the filling <NUM> is in the range of, for example, from <NUM> wt. % to <NUM> wt. %, preferably from <NUM> wt. % to <NUM> wt. Such a water content prevents the occurrence of staining in a wrapping paper and improves rolling-up processability during production of the substrate section 110A. The filling <NUM> may also contain one or two or more types of flavorings. The types of such flavorings are not particularly limited, but menthol is preferred from the viewpoint of impartation of good smoking flavor.

Next, the following will describe the positional relationship between the smoking article <NUM> and the heating assembly <NUM> when the smoking article <NUM> is inserted into the flavor inhaler <NUM>. <FIG> schematically illustrates the positional relationship in the axial direction of the substrate section 110A of the smoking article <NUM> with respect to the heating member <NUM> and the inner cylinder <NUM> in the flavor inhaler <NUM> of this embodiment. As referred to herein, the "axial (line)" refers to the central axis of the first opening 42a in the flavor inhaler <NUM>. When the smoking article <NUM> is inserted through the first opening 42a, the axial line of the first opening partially overlaps with the central axis of the smoking article <NUM>.

When the axial length of the heating member <NUM> is denoted as D0 and the axial length of the substrate section 110A of the smoking article <NUM> is denoted as L0, the relationship of D0 < L0 holds. Further, the ratio of D0/L0 is in the range of from <NUM> to <NUM>, preferably from <NUM> to <NUM>, and can be typically <NUM>. Therefore, when the length L0 of the substrate section 110A is <NUM>, the length D0 of the heating member <NUM> is in the range of from <NUM> to <NUM>, preferably from <NUM> to <NUM>, and can be typically <NUM>.

By reference to <FIG>, the upstream end of the substrate section 110A can protrude upstream for a length of D1 from the upstream end of the heating member <NUM>. Since the heating member <NUM> does not extend to the radial outside of the portion of the substrate section 110A which protrudes from the heating member <NUM>, said protruding portion can have a somewhat lower internal temperature than the other portion of the substrate section 110A. Therefore, an aerosol can be prevented from being generated at and near the upstream end of the substrate section 110A, so that an aerosol generated there can be prevented from condensing in the air flow passage or from flowing back through the air flow passage and leaking outside the flavor inhaler.

The ratio of the protruding length D1 to the overall length L0 of the substrate section 110A (D1/L0) is in the range of from <NUM> to <NUM>, preferably from <NUM> to <NUM>, and can be typically <NUM>. Such being the case, when the overall length L0 of the substrate section 110A is <NUM>, the protruding length D1 is in the range of from <NUM> to <NUM>, preferably from <NUM> to <NUM>, and can be typically <NUM>. The protruding length D1 as referred to herein can also be defined as the axial distance between the upstream end of the heating member <NUM> and the upstream end of the inner cylinder <NUM>.

By reference to <FIG>, the downstream end of the heating member <NUM> can protrude downstream for a length of D2 from the downstream end of the substrate section 110A. Therefore, the heating member <NUM> can adequately heat the downstream end of the substrate section 110A and its vicinity, thereby preventing deficiency in the amount of an aerosol generated in that region or condensation of the generated aerosol. The ratio of the protruding length D2 of the heating member <NUM> to the overall length L0 of the substrate section 110A (D2/L0) is in the range of from <NUM> to <NUM>, preferably from <NUM> to <NUM>, and can be typically <NUM>. Such being the case, when the overall length L0 of the substrate section 110A is <NUM>, the protruding length D2 of the heating member <NUM> is in the range of from <NUM> to <NUM>, preferably from <NUM> to <NUM>, and can be typically <NUM>.

Claim 1:
A heating assembly (<NUM>) comprising:
an inner cylinder (<NUM>) into which a flavor-generating article (<NUM>) can be inserted; and
a heating member (<NUM>),
characterized by:
an outer cylinder (<NUM>) disposed outside the inner cylinder (<NUM>); and
a pair of sealing members (<NUM>) disposed between each of the ends of the inner cylinder (<NUM>) and each of the ends of the outer cylinder (<NUM>) so as to form a closed space (<NUM>) having heat insulation function between the inner cylinder (<NUM>) and the outer cylinder (<NUM>);
wherein the heat conductivity of the sealing members (<NUM>) is lower than that of the inner cylinder (<NUM>).