TW201924549A - Cartridge for aerosol inhaler, aerosol inhaler, and metal heater for aerosol inhaler - Google Patents

Abstract

Provided are a metal heater for aerosol inhaler which is improved as compared with the prior art, a cartridge for aerosol inhaler having the same, and an aerosol inhaler. A cartridge for aerosol inhaler includes a liquid storage portion for storing an aerosol generation liquid, and a thin metal heater for atomizing the aerosol generation liquid supplied from the liquid storage portion, the metal heater having a front surface, a back surface opposite to the front surface, and side surfaces connecting the front surface and the back surface, a tapered protrusion that protrudes in a tapered shape in a direction different from a virtual line extending from the front surface to the back surface being provided on at least a part of the side surface, the tapered protrusion including a first tapered surface formed in a concavely curved shape toward a front end of the tapered protrusion with a front edge portion where the front surface and the side surface are connected as a base end, and a second tapered surface formed in a concavely curved shape toward the front end of the tapered protrusion with an back edge portion where the back surface and the side surface are connected as a base end.

Description

Metal heater for mist suction device, mist suction device and mist suction device

The present invention relates to a metal heater for a mist suction device, a mist suction device and a mist suction device.

There is known a mist absorbing device that provides mist generated by a user's suction action. In the mist suction device, an example in which the mist generating liquid is atomized (aerosolized) in the atomizing portion by electric heating by a heater is exemplified. As the mist generating liquid, a liquid for generating a mist is known, and contains glycerin (G) or propylene glycol (PG) or the like.

Further, in recent years, an atomizing unit having a liquid holding member that sucks and holds a mist generating liquid from a liquid storage tank that stores a mist generating liquid, and the like, and a surface of the liquid holding member are provided. A heater (for example, refer to Patent Document 1, etc.).

[Previous Technical Literature] [Patent Literature]

Patent Document 1: US Patent Application Publication No. 2015/0136156

Patent Document 2: Japanese Patent Publication No. 2014-527835

Here, the conventional metal heater for the mist suction device is considered to have room for improvement. The present invention has been made in view of such an actual situation, and an object of the present invention is to provide a metal heater for a mist suction device which is improved over the prior art, and a mist for a mist suction device including the metal heater for the mist suction device, and a mist. Suction device.

The mist for a mist suction device according to the present invention includes: a liquid storage unit that stores a mist generation liquid; and a sheet-shaped metal heater that atomizes the mist generation liquid supplied from the liquid storage unit; and the metal heater system a surface having a back surface facing the surface and a side surface connecting the front surface and the back surface, wherein at least a portion of the side surface is provided with a tapered protruding portion that faces the imaginary from the surface toward the back surface The tapered protruding portion has a first tapered surface having a concave curved surface formed at a front end of the tapered protruding portion with a front side edge portion connected to the front surface and the side surface as a base end; And a second tapered surface having a concave curved surface formed at a front end of the tapered protruding portion with the back side edge portion connecting the back surface and the side surface as a base end.

According to the invention adopting the above configuration, due to the metal The side surface of the heater is formed with a tapered projection, so that the surface area of the metal heater can be sufficiently ensured. More specifically, when compared with the same cross-sectional area, the metal heater of the present invention having a tapered projection can be used as compared with a heater having a circular cross section or a rectangular cross section without a tapered projection. The surface area increases. As a result, the heat generated by the metal heater of the present invention can be efficiently transmitted to the mist generating liquid, so that the vaporization of the mist generating liquid can be promoted. That is, atomization of the mist generating liquid can be promoted, and mist can be generated more efficiently than in the past.

Further, in the crucible for a mist suction device of the present invention, the protruding length of the base end to the tip end of the tapered protruding portion may be 5% or more and 20% or less with respect to the thickness dimension of the metal heater.

Moreover, in the crucible for a mist suction device of the present invention, the tip end of the tapered protruding portion may be located substantially at the center in the thickness direction of the metal heater.

Further, in the crucible for a mist suction device of the present invention, the metal heater may integrally form a heating portion and an electrode portion that generate heat when energized to heat the mist generating liquid.

Further, in the crucible for a mist suction device of the present invention, the metal heater may be a linear heater having a linear shape.

Further, in the mist for a mist suction device of the present invention, the metal heater may be a plate heater having a plate shape.

Further, in the crucible for a mist suction device of the present invention, a through hole penetrating the metal heater in a thickness direction may be provided, and the tapered projection portion may be provided on an inner circumferential side surface of the through hole.

Moreover, in the crucible for a mist suction device of the present invention, a plurality of the through holes may be arranged in the metal heater.

Further, the mist suction device of the present invention may further include: a liquid holding member provided between the liquid storage portion and the metal heater and holding the mist generating liquid supplied from the liquid storage portion, wherein the metal heating The device is disposed in contact with the aforementioned liquid holding member.

Further, in the cartridge for a mist suction device of the present invention, the metal heater may be a plate heater having a plate shape, and the surface or the back surface may be provided in contact with the liquid holding member, and the metal heater may be arranged The plurality of through holes penetrating in the thickness direction are provided with the tapered protrusions on the inner peripheral side surface of each of the through holes.

Further, the present invention may be specifically configured as a mist suction device including any of the above-described mist suction devices. Further, for example, the mist suction device of the present invention includes: a liquid storage unit that stores a mist generation liquid; and a sheet-shaped metal heater that atomizes the mist generation liquid supplied from the liquid storage unit; The heater has a surface, a back surface facing the surface, and a side surface connecting the front surface and the back surface, and at least a portion of the side surface is provided with a tapered protruding portion that faces toward and from the surface The imaginary line of the back surface is protruded in a tapered shape in a different direction, and the tapered protruding portion has a concave curved surface formed at a front end of the front side of the tapered protruding portion with a front side edge portion connecting the front surface and the side surface as a base end And a second tapered surface having a concave curved surface formed at a front end of the tapered protruding portion with a back side edge portion connecting the back surface and the side surface as a base end.

Further, the present invention may also be specifically a metal heater for a mist suction device. In other words, the present invention is a sheet-shaped metal heater for a mist-aspirator that atomizes a mist generating liquid, and the metal heater for a mist-absorbing device has a surface, a back surface facing the surface, and a surface and a back surface. a side surface of the side surface; at least a portion of the side surface is provided with a tapered protruding portion that protrudes in a tapered shape in a direction different from an imaginary line from the surface to the back surface, wherein the tapered protruding portion has: a first tapered surface having a concave curved surface formed at a front end of the front surface of the tapered protruding portion with a front side surface connecting the front surface and the side surface; and a back side edge portion connecting the back surface and the side surface as a base end A second tapered surface having a concave curved surface is formed toward the front end of the tapered projection.

According to the present invention, it is possible to provide a technique relating to a heater for a mist suction device which is improved over the past.

1‧‧‧Fog suction device

10‧‧‧匣

10a‧‧‧First housing

11‧‧‧First connector

12‧‧‧ nozzle

13‧‧‧Liquid Storage Department

15‧‧‧Atomization unit

16a, 16b‧‧‧ male electrode latch

17‧‧‧Internal access

18‧‧‧Air intake

20‧‧‧Power bar

20a‧‧‧Second shell

21‧‧‧Second connector 21

22‧‧‧Battery

23‧‧‧Electronic Control Department

24a, 24b‧‧‧ female terminal

151‧‧‧Liquid holding member

151a‧‧‧ surface

152‧‧‧Metal heater

153‧‧‧Atomization space

1521‧‧・heating department

1521A‧‧・heating department

1522a, 1522b‧‧‧ electrode parts

1523, 1523A‧‧‧Conical protrusions

1524‧‧‧through holes

A1‧‧‧heating section forming area

A2, A3‧‧‧ electrode formation area

BM1‧‧‧Metal substrate

D1‧‧‧ line length

D2‧‧‧ arc length

E1, E1'‧‧‧ side edge

E2, E2'‧‧‧ back side edge

FE‧‧‧ front end

H1, H2‧‧‧ etched holes

L1‧‧‧ imaginary line

L2‧‧‧Outstanding length dimensions

P‧‧‧Heater Formation Department

R‧‧‧ Frame Department

R1‧‧‧Outer frame

R2‧‧‧ Connection Department

S1‧‧‧ surface

S2‧‧‧Back

S3‧‧‧ side

S3’‧‧‧ inner side

TS1, TS1'‧‧‧ first cone

TS2, TS2'‧‧‧ second cone

Fig. 1 is a schematic view showing a mist suction device of the first embodiment.

Fig. 2A is an explanatory view of the metal heater of the first embodiment.

Fig. 2B is an explanatory view of the metal heater of the first embodiment.

Fig. 3 is a schematic cross-sectional view showing a cross section of a heating unit in the metal heater of the first embodiment.

Fig. 4 is a conceptual explanatory view showing a method of manufacturing the metal heater of the first embodiment.

Figure 5 is a process of slowly dissolving a metal substrate by double-sided etching. Conceptual illustration.

Fig. 6 is a schematic view showing a metal substrate after etching in the first embodiment.

Fig. 7 is a schematic view showing a heater forming portion that is detached from the frame portion after etching the metal substrate.

Fig. 8 is a view showing an arrangement of a heating portion of the atomization unit of the first embodiment with respect to the liquid holding member.

Fig. 9A is a view showing an arrangement of a heating unit of the atomization unit according to a modification of the first embodiment with respect to the liquid holding member.

Fig. 9B is a view showing an arrangement of a heating unit of the atomization unit according to a modification of the first embodiment with respect to the liquid holding member.

Fig. 9C is a view showing an arrangement of a heating unit of the atomization unit according to a modification of the first embodiment with respect to the liquid holding member.

Fig. 10A is a schematic view showing the metal heater of the second embodiment.

Fig. 10B is a schematic view showing the metal heater of the second embodiment.

Fig. 11 is a schematic view showing a part of a cross section of the heating unit of the second embodiment.

Fig. 12 is a view showing the relationship between the liquid holding member and the metal heater in the atomizing unit of the second embodiment.

Here, an embodiment of the mist for a mist suction device, a mist suction device, and a heater for a mist suction device according to the present invention will be described with reference to the drawings. Moreover, the dimensions, materials, shapes, relative arrangement, and the like of the constituent elements described in the present embodiment are not specifically described unless otherwise specified. It is indicated that the technical scope of the invention is limited only to those.

<Embodiment 1>

Fig. 1 is a schematic view showing a mist suction device 1 of the first embodiment. The mist suction device 1 includes a crotch portion 10 (for a mist suction device) and a power supply rod 20 that are detachably connected. The crotch portion 10 is provided with a first connector 11 at one end. The power bar 20 is provided with a second connector 21 at one end. The first connector 11 of the crotch portion 10 and the second connector 21 of the power bar 20 are mechanically and electrically connected, for example, by a fitting method. However, the connection manner of the first connector 11 and the second connector 21 is not limited to the fitting method, and various well-known connection methods such as a screw connection may be used. The crotch portion 10 has a first housing 10a. Further, a mouthpiece 12 as a suction port is provided at an end portion of the crotch portion 10 on the opposite side of the first connector 11. In Fig. 1, the first connector 11 and the second connector 21 are represented by an abstract diagram.

The power supply rod 20 has a second casing 20a in which a battery 22, an electronic control unit 23, and the like are housed. For example, the battery 22 is, for example, a lithium ion battery or the like. Further, the battery 22 and the electronic control unit 23 are connected via an electric wire, and the electric control unit 23 controls the electric power supply from the electric heater of the battery 22 to the crotch portion 10. The power supply bar 20 is provided with, for example, a suction sensor or a manual switch (none of which is shown). For example, the suction sensor is used to detect the suction (suction) of the nozzle 12 by the user, whereby the user's smoking request can be detected.

The power bar 20 is provided with a suction sensor, and the suction sensor can also be connected to the electronic control unit 23 via a wire, and when the suction sensor detects the suction of the nozzle 12 by the user (suction Electronic control department The battery 22 can also be controlled to cause the battery 22 to supply power to the electric heater of the crotch portion 10. As the suction sensor, for example, a pressure sensor or a thermal flow meter (MEMS flow sensor or the like) that detects a negative pressure generated by a user's suction can be suitably used. Further, when the power supply bar 20 is provided with a manual switch, the manual switch is connected to the electronic control unit 23 via a wire, and when the electronic control unit 23 detects that the manual switch is operated to be in an ON state, the electronic control unit 23 controls the battery 22, Further, power is supplied from the battery 22 to the electric heater of the crotch portion 10.

Next, the crotch portion 10 will be described. As described above, the first connector 11 is provided at one end of the crotch portion 10, and the suction nozzle 12 is provided at the other end. A liquid storage portion 13 in which a mist generating liquid is stored is provided in the first casing 10a of the crotch portion 10. The first casing 10a is, for example, a bottomed cylindrical casing, and one of the first casings 10a is opened, and the suction nozzle 12 is provided on the bottom surface side. The mist generating liquid may be, for example, a mixed liquid of glycerin (G), propylene glycol (PG), nicotine solution, water, perfume, or the like. The mixing ratio of the materials contained in the mist generating liquid can be appropriately changed. Further, the mist generating liquid may not contain the nicotine solution. Further, inside the liquid storage unit 13, a core material for impregnating and holding the mist generating liquid or the like may be accommodated together with the mist generating liquid.

The crotch portion 10 has an atomizing unit 15 for atomizing the mist generating liquid supplied from the liquid storage portion 13 and generating a mist. In the present embodiment, the liquid storage portion 13 has an open end, and a liquid holding member 151 is disposed in the vicinity of the open end. As the liquid holding member 151, it is preferable to use a suitable material which can absorb and retain the mist generating liquid by capillary force. The liquid holding member 151 may be a core composed of, for example, glass fiber or the like. The member may be a porous foam or cotton. In the present embodiment, the liquid holding member 151 is formed in a planar shape. The liquid holding member 151 is present between the liquid storage portion 13 and a metal heater 152 to be described later, and can hold the mist generating liquid supplied from the liquid storage portion 13 in a liquid state.

The atomizing unit 15 includes the above-described liquid holding member 151 and a sheet-shaped metal heater 152. The term "sheet shape" as used herein refers to a form in which the thickness dimension is relatively small compared to the long side dimension of the metal heater 152 in the longitudinal direction X (see FIG. 2A to be described later), and is not specifically limited. The shape of the cross section orthogonal to the long side direction X. The shape of the metal heater 152 may be a linear shape (line shape), a stripe shape, a flat plate shape, or the like, but other shapes may be employed.

2A and 2B are explanatory views of the metal heater 152 of the first embodiment. The metal heater 152 is an electrically heated metal heater and is a linear heater having a linear heating portion 1521. Of course, the linear metal heater 152 belongs to a sheet-shaped heater. FIG. 2A is a schematic perspective view showing the heating unit 1521. Fig. 2B is a plan view showing the metal heater 152 in the upper stage, and a side view of the metal heater 152 in the lower stage. The metal heater 152 includes a pair of electrode portions 1522a and 1522b provided at both ends of the heating portion 1521. The metal heater 152 may be, for example, stainless steel, nichrome, iron chrome aluminum alloy, or the like. Since the electrode portions 1522a and 1522b are set to have a larger width dimension than the heating portion 1521, the electrode portions 1522a and 1522b are formed to have a smaller electric resistance than the heating portion 1521.

In the present embodiment, the shapes of the electrode portions 1522a and 1522b are not specifically limited. And, among the metal heaters 152, about The position and size of the electrode portions 1522a and 1522b are also not specifically limited. The details of the metal heater 152 will be described later, but the heating portion 1521 of the metal heater 152 and the pair of electrode portions 1522a and 1522b are integrally formed of the same material. The metal heater 152 is disposed in a state in which the heating portion 1521 is in contact with (contacted with) the liquid holding member 151. When the metal heater 152 is energized, the heating portion 1521 generates heat, thereby heating and vaporizing the mist generating liquid existing in the periphery.

Further, the male electrode pins 16a and 16b are joined to the pair of electrode portions 1522a and 1522b of the metal heater 152 (see FIGS. 1 and 2B). Each of the electrode portions 1522a and 1522b and the male electrode pins 16a and 16b can be joined by welding or joined by caulking, and the joining method is not specifically limited. Further, as shown in Fig. 1, the second connector 21 of the power supply bar 20 is provided with a female terminal 24a that can be fitted to the male electrode pins 16a and 16b on the first connector 11 side of the flange portion 10, 24b. For example, when the first connector 11 of the crotch portion 10 is fitted into the second connector 21 of the power supply rod 20, the male electrode pins 16a, 16b on the first connector 11 side are fitted to the second connector 21 side. The female terminals 24a, 24b are electrically connected to the female terminals 24a, 24b by the male electrode pins 16a, 16b. Further, the male electrode pins 16a and 16b and the female terminals 24a and 24b are formed to be insulated from each other by an insulating member (not shown). Further, the female terminals 24a and 24b of the second connector 21 are connected to the positive terminal and the negative terminal of the battery 22, for example, via wires (not shown). However, the connection manner of the first connector 11 and the second connector 21 is not limited to a pin connection, and various connection methods may be employed.

Further, in the first casing 10a of the dam portion 10, an atomization space 153 is provided around the metal heater 152 of the atomization unit 15. The air intake port 18 for taking in air from the outside is provided in the first casing 10a. When the user sucks the suction nozzle 12, the air taken in from the outside through the air intake port 18 of the first casing 10a is guided to the atomization space 153. Then, the mist generating liquid vaporized by the metal heater 152 is mixed with the air and cooled, whereby mist is generated in the atomizing space 153. Further, as shown in Fig. 1, the atomization space 153 communicates with the suction nozzle 12 via the internal passage 17 formed in the first casing 10a. Thereby, the mist generated in the atomizing space 153 of the crotch portion 10 reaches the suction nozzle 12 through the internal passage 17, and is supplied to the user. Further, the number, position, size, and the like of the air intake ports 18 provided in the first casing 10a are not specifically limited.

Next, the details of the atomizing unit 15 in the present embodiment will be specifically described focusing on the structure of the metal heater 152. Fig. 3 is a schematic cross-sectional view showing a heating portion 1521 of the metal heater 152 of the first embodiment. The cross section of the heating portion 1521 among the metal heaters 15 is defined as a cross section orthogonal to the longitudinal direction indicated by the symbol X in the second A diagram.

As shown in Fig. 3, the heating portion 1521 of the metal heater 152 has a surface S1, a back surface S2 facing the surface S1, and a pair of side surfaces S3 connecting the surface S1 and the back surface S3. In the example shown in Fig. 3, the surface S1 and the back surface S2 are parallel. Further, at least a part of the pair of side faces S3 is provided with a tapered protruding portion 1523 that protrudes in a tapered shape toward the side. More specifically, the tapered protrusion 1523 is oriented toward and from the surface S1 The imaginary line L1 of the back surface S2 protrudes in a different direction. In the aspect shown in FIG. 3, as an example, the case where the tapered protruding portion 1523 protrudes in a direction orthogonal to the imaginary line L1 from the front surface S1 toward the back surface S2 is shown. Hereinafter, the direction in which the front surface S1 and the back surface S2 extend is defined as the "width direction" of the heating portion 1521, and the dimension in the width direction of the heating portion 1521 is defined as "width dimension". Further, in the cross section of the heating portion 1521, the direction orthogonal to the width direction is defined as "thickness direction", and the dimension in the thickness direction is defined as "thickness dimension". Further, the imaginary line L1 from the surface S1 toward the back surface S2 is parallel to the thickness direction of the heating portion 1521 and orthogonal to the width direction. Further, the protruding direction of the tapered protruding portion 1523 is parallel to the width direction of the heating portion 1521.

Next, the details of the tapered protrusion 1523 will be described. The tapered protruding portion 1523 is formed by a pair of first tapered surfaces TS1 and second tapered surfaces TS2 which are formed in a concave curved shape. The first tapered surface TS1 has a concave curved surface shape with the front side edge portion E1 connecting the front surface S1 and the side surface S3 as a base end and facing the front end FE of the tapered protruding portion 1523. Further, the second tapered surface TS2 has a concave curved surface shape with the back side edge portion E2 connecting the back surface S2 and the side surface S3 as a base end and facing the front end FE of the tapered protruding portion 1523. Further, as shown in FIG. 3, in the heating portion 1521 of the metal heater 152, the front side edge portion E1 and the back side edge portion E2 formed at the base ends of the tapered protruding portions 1523 of the respective side faces S3 are respectively formed. The positions in the width direction of the heating portion 1521 are preferably equal to each other.

Fig. 4 is a conceptual explanatory view showing a method of manufacturing the metal heater 152 of the first embodiment. Symbol BM1 is used to make metal heaters 152 metal substrate. Here, as an example of a method of manufacturing the metal heater 152, an example in which the metal substrate BM1 is subjected to photo-etching processing to form the metal heater 152 will be described. The etching is a surface processing technique using a corrosive action such as a chemical, and a desired portion of the surface of the material to be used is subjected to a resist treatment, and an unnecessary portion is dissolved by an etchant (etching liquid) to obtain a desired shape. The photo-etching technique is a precision processing technique in which the above-described etching processing technique combines light, that is, precision photo technology and precision image technology, and uses an etching solution after forming a necessary pattern of a corrosion-resistant film by using a photo-engraving program on a material such as metal. A chemical precision machining technique that removes unwanted portions and thereby partially corrodes them. The portion of the metal substrate BM1 in which the oblique line is drawn is a region where the metal substrate BM1 is dissolved by the etching liquid. Further, the symbol A1 in Fig. 4 is a heating portion forming region in which the heating portion 1521 of the metal heater 152 is formed. Further, the symbols A2 and A3 are electrode portion forming regions for forming the electrode portions 1522a and 1522b of the metal heater 152, respectively.

Next, when an etching procedure for the metal base material BM1 is described, first, a photoresist is applied to both surfaces (surface S1 and back surface S2) of the metal base material BM1 shown in FIG. 4 (step 1: Coating with photoresist). The photoresist is used as a mask for protecting the metal substrate BM1 from etching by the etching liquid, and is a photosensitive resin. Next, among the photoresists to be applied to the entire surface of the metal substrate BM1 by the light mask, except for the region (hatched region) for dissolving the metal substrate BM1 by etching (also The heating portion forming region A1, the electrode portion forming regions A2, A3, and the latter will be described later in Fig. 6. Exposure is performed in a state in which the frame portion R) including the outer frame portion R1 and the connection portion R2 is covered, and the photoresist corresponding to the region to be dissolved (hatched region) is exposed (step 2: exposure). Next, the photoresist of the photosensitive portion is removed using a developing solution (step 3: development). Thereby, the surface S1 and the back surface S2 of the region to be dissolved (hatched region) are exposed, and the metal portions in the state where the other portions (the heating portion forming region A1 and the electrode portion forming regions A2 and A3) are covered with the photoresist are obtained. Material BM1.

The metal base material BM1 obtained in the step 3 (the heating portion forming region A1 and the electrode portion forming regions A2 and A3 are covered with the photoresist by the photoresist) is immersed in the etching liquid for a predetermined period of time. In the present embodiment, double-sided etching processing is performed on both surfaces (surface S1 and back surface S2) of the metal base material BM1 by etching. Fig. 5 is a conceptual explanatory view showing a process of slowly dissolving the metal base material BM1 by double-sided etching. The concept of the oblique arrow symbol in Fig. 5 indicates the direction of dissolution when the etching solution dissolves the metal substrate BM1. As shown in the figure, when the metal base material BM1 is subjected to double-side etching, the partial metal base material BM1 remains in a direction orthogonal to the direction in which the etching liquid dissolves the metal base material BM1, whereby the third surface can be formed. The tapered protrusion 1523 is illustrated.

When the double-sided etching process for the metal substrate BM1 is completed, the metal substrate BM1' after the etching as shown in Fig. 6 can be obtained. Symbols H1 and H2 in the drawing are etched holes formed by etching. A tapered projection 1523 is formed at an edge of the metal base material BM1' (in other words, a peripheral portion of the etching holes H1 and H2). Further, in Fig. 6, the symbol R is used as a frame portion of the metal heater 152. Example shown in Figure 6 In the middle, the frame portion R includes an outer frame portion R1 in the outer peripheral region of the metal base material BM1', and a connecting portion R2 that connects the outer frame portion R1 and the heater forming portion P. The heater forming portion P is a region where the metal heater 152 is formed among the metal base materials BM1'.

In the process of the metal heater 152, the heater forming portion P is detached from the connecting portion R2 of the frame portion R. Therefore, among the electrode portion forming regions A2 and A3 of the heater forming portion P, the side faces of the heater forming portions corresponding to the portions respectively connected to the connecting portion R2 are not provided with the tapered protruding portions 1523 as described above. Next, the heater forming portion P (see FIG. 7) obtained as described above is a pair of electrode portions 1522a and 1522b (electrode portion forming regions A2 and A3) with respect to the heating portion 1521 (heating portion forming region A1). The erecting method is applied to the bending process. Thereby, the metal heater 152 as described in FIGS. 2 and 3 is completed. Further, as shown in Fig. 1, the metal heater 152 is disposed at a different position in the longitudinal direction of the heating portion 1521 and the pair of electrode portions 1522a and 1522b with respect to the crotch portion 10 (for the mist suction device). In addition, the etching liquid used in the production of the metal heater 152 may be appropriately selected depending on the metal substrate, but may be appropriately selected from, for example, a ferric chloride solution, a ferric nitrate solution, hydrogen fluoride, nitric acid, or the like. Further, in the above example, the end portions of the heater forming portion P are bent to form the pair of electrode portions 1522a and 1522b. However, the present invention is not limited thereto, and the bending process is not essential in the process of the metal heater 152. Further, as described above, the metal heater 152 in the present embodiment has a portion where the tapered portion 1523 is not provided in a part of the side faces of the electrode portions 1522a and 1522b, but is not limited thereto, and may be in the metal. The entire side of the heater 152 The domain is provided with a tapered protrusion 1523.

Fig. 8 is a schematic view showing an arrangement of the heating portion 1521 of the metal heater 152 with respect to the liquid holding member 151 of the atomizing unit 15. The example shown in FIG. 8 is a state in which the back surface S2 of the heating portion 1521 of the metal heater 152 abuts (contacts) the liquid holding member 151, and the liquid holding member 151 is provided with a heating portion 1521. As described above, since the liquid holding member 151 absorbs and holds the mist generating liquid supplied from the liquid storage portion 13, the mist generating liquid is moisturized around the heating portion 1521. Here, when the electronic control unit 23 detects the smoking request of the user and starts to supply power to the metal heater 152 of the crotch portion 10 from the battery 22, the heating portion 1521 generates heat, thereby vaporizing the mist generating liquid. . At this time, according to the heating portion 1521 of the present embodiment, since the tapered protruding portion 1523 is formed on the side surface S3, the surface area can be sufficiently ensured. More specifically, when the cross-sectional area is compared with the same cross-sectional area, the heating portion 1521 including the tapered protruding portion 1523 is more than a simple circular or rectangular heating portion in which the cross-sectional portion of the tapered protruding portion 1523 is not provided. Can increase the surface area. As a result, the heat generated in the heating portion 1521 can be efficiently transmitted to the mist generating liquid, so that vaporization of the mist generating liquid can be promoted. In other words, according to the metal heater 152 of the present embodiment, atomization of the mist generating liquid can be promoted, and mist can be generated more efficiently than in the related art.

Further, according to the method of manufacturing the metal heater 152 of the present embodiment, the metal base material BM1 of the metal heater 152 is double-sided etched, and the tapered protruding portion 1523 is formed on the side surface S3 of the heating portion 1521. Photoetching is based on precise photo images to determine the shape of the process. This has the advantage of being able to perform microfabrication with high precision. In other words, in the case of forming the tapered projecting portion 1523 in the heating portion 1521 of the metal heater 152, the microfabrication which is difficult in the metal cutting process or the like can be easily performed by photo etching. The method of manufacturing the metal heater 152 can be considered in various methods, for example, by metal cutting, but it is preferably manufactured by photolithography. Further, when the metal heater 152 is manufactured, the type of the etching liquid used for controlling the photo-etching, the type and thickness of the metal substrate, the immersion time of the metal substrate in the etching liquid, the pressure of the etching liquid, the temperature of the etching liquid, and the like are transmitted. With various parameters, the tapered protrusion 1523 of the desired shape can be easily formed.

For example, the elongated metal substrate is immersed in the etching liquid (more precisely, the oblique line region in the above-mentioned FIG. 4 (the region in which the photoresist is removed from the metal substrate BM1), thereby forming the opening portion By the soaking time), the protruding length dimension L2 of the tapered protrusion 1523 described later can be shortened (refer to FIG. 3). Further, for example, by increasing the temperature of the etching liquid used for photo etching, the speed at which the metal substrate is corroded (dissolved) can be increased. Therefore, if the same immersion time is used in the etching liquid, the protruding length can be shortened. L2. Further, regarding the type of the metal substrate, for example, when a metal substrate of a type which is easily corroded is used, when compared with the same immersion time in the etching liquid, it is compared with a metal substrate of a type which is relatively resistant to corrosion. In this case, the above-mentioned protruding length dimension L2 can be shortened. Further, for example, when the thickness of the metal base material is increased, the corrosion rate in the width direction tends to decrease, so that it is easier to secure the above-described protruding length dimension L2. Further, the above embodiment illustrates the wet etching by using an etching solution Although the heating portion 1521 of the metal heater 152 is formed as an example of the tapered protruding portion 1523, the tapered protruding portion 1523 may be formed in the heating portion 1521 by dry etching.

Moreover, according to the present embodiment, since the metal heater 152 is manufactured by photolithography, the heating portion 1521 can be integrally formed with the pair of electrode portions 1522a and 1522b. According to this configuration, the shape and/or the size of the electrode portions 1522a and 1522b connected to the respective male electrode pins 16a and 16b can be freely set. Therefore, for example, the electrode portions 1522a and 1522b can be reduced with respect to the male electrode pins. The heater resistance values caused by the bonding method or the installation area of 16a and 16b are uneven. Further, as described above, since it is not necessary to weld the electrode portions 1522a and 1522b to the heating portion 1521, it is easier to obtain the metal heater 152 of stable quality. In particular, in the present embodiment, the heating portion 1521 (heating portion forming region A1) is not connected to the frame portion R of the metal base material BM1, but the electrode portions 1522a and 1522b (electrode portion forming regions A2 and A3) are connected to each other. Since the frame portion R of the metal base material BM1 (specifically, the connecting portion R2) is formed, the unevenness of the resistance values among the longitudinal direction X of the heating portion 1521 can be reduced. As a result, uniform heating in the heating portion 1521 is easily obtained, and thus the atomization operation can be stabilized. However, each of the electrode portions 1522a and 1522b may be welded to the heating portion 1521 to manufacture the metal heater 152.

Further, in the metal heater 152 of the present embodiment, as shown in FIG. 3, the front end FE of the tapered projection 1523 of the heating portion 1521 among the metal heaters 152 is located substantially at the center in the thickness direction of the heating portion 1521. Here, the tapered protrusion 1523 of the heating portion 1521 is used. The arrangement of the front end FE in the approximate center of the thickness direction of the heating portion 1521 means that the front end FE is disposed to be separated from the front surface S1 and the back surface S2 by a predetermined amount or more. Therefore, when the heating portion 1521 of the metal heater 152 is brought into contact with the liquid holding member 151, when the pressure is applied only to the tapered protruding portion 1523, the deformation of the tapered protruding portion 1523 is easily avoided. As a result, the unevenness of the resistance value of each batch of the heating portion 1521 can be reduced.

In addition, the front end FE of the tapered portion 1523 of the heating portion 1521 is disposed substantially at the center in the thickness direction of the heating portion 1521, whereby the front surface S1 side and the rear surface S2 side can be centered on the front end FE of the tapered protruding portion 1523. The shape is set to a symmetrical shape. Therefore, it can be found that even if any one of the surface S1 and the back surface S2 of the heating portion 1521 is brought into contact with the liquid holding member 151, substantially the same function can be exhibited. Further, when the metal heater 152 is assembled, it is expected that it is not necessary to confirm the effect of the surface S1 and the back surface S. Moreover, in order to achieve the above effect, the front end FE of the tapered protruding portion 1523 of the heating portion 1521 is preferably located within a range of ±10% from the center position in the thickness direction of the heating portion 1521.

Further, according to the method of manufacturing the metal heater 152 of the present embodiment, since the metal base material BM1 of the metal heater 152 is subjected to double-sided etching, the tapered protruding portion 1523 is formed on the side surface S3 of the heating portion 1521. The front end FE of the tapered protruding portion 1523 of the heating portion 1521 can be easily aligned at substantially the center in the thickness direction of the heating portion 1521.

Further, in the metal heater 152 of the present embodiment, the protruding length L2 from the base end (the front side edge portion E1 and the back side edge portion E2) of the tapered protruding portion 1523 of the heating portion 1521 to the front end FE (see the third Figure) The range of 5% or more and 20% or less of the thickness of the heating portion 1521 of the metal heater 152 is preferably in the range of 10% or more and 15% or less. As described above, the ratio of the protruding length dimension L2 of the thickness of the tapered portion 1523 to the thickness of the heating portion 1521 is set, thereby ensuring that the heating portion 1521 has a sufficient surface area. Thereby, the heating portion 1521 can be brought into contact with more of the mist generating liquid, and as a result, the atomization efficiency of the heating portion 1521 can be improved, and the transmission can suppress the increase in the latent heat which causes the heating portion 1521 itself to generate heat, and the relative amount of electricity can be increased. The calorific value is set to an appropriate value.

Further, among the tapered projections 1523 of the heating unit 1521 of the present embodiment, the length of the line segment connecting the front side edge portion E1 (the back side edge portion E2) and the front end FE by a straight line is D1 (see FIG. 3). When the arc length of the first tapered surface TS1 (second tapered surface TS2) of the tapered projection 1523 is D2 (see FIG. 3), it is preferable to form a range of 1 < (D2/D1) < 1.29. That is, it is preferable that the ratio of the arc length D2 to the length D1 of the line segment is set to be larger than 1 and smaller than 1.29, and by setting in this way, the surface area of the tapered protruding portion 1523 of the heating portion 1521 that can come into contact with the mist generating liquid can be increased. Further, the ratio of the arc length D2 to the line length D1 is sufficient as long as at least one of the pair of tapered protrusions 1523 in the heating portion 1521 is satisfied, and the tapered protrusion 1523 can be brought into contact with the mist generating liquid. The effect of increasing the surface area.

Further, among the heating portions 1521 of the metal heater 152, the positions of the front side edge portion E1 and the back side edge portion E2 of the tapered protruding portion 1523 formed on the pair of side faces S3 in the width direction of the heating portion 1521 are equal to each other. And, the protruding length dimension L2 of the tapered protrusion 1523 (see According to FIG. 3, the type of the metal base material BM1 used for the heating portion 1521 of the metal heater 152, the type and thickness of the etching liquid, the immersion time of the metal substrate BM1 in the etching liquid, the pressure of the etching liquid, and etching can be transmitted. Various parameters such as the temperature of the liquid are thereby adjusted to a desired length.

In addition, from the viewpoint of efficiently atomizing the mist generating liquid in the heating portion 1521 of the metal heater 152 and the metal heater 152 by photolithography of the metal base material BM1, it is preferable to heat the portion The dimensions of 1521 are set as follows. For example, the thickness of the cross section of the heating portion 1521 is preferably 20 μm or more and 120 μm or less, and more preferably 50 μm or more and 120 μm or less. Moreover, the width dimension of the cross section of the heating portion 1521 is preferably 20 μm or more and 120 μm or less, and more preferably 50 μm or more and 120 μm or less. When the thickness and the width dimension of the heating portion 1521 are set to be less than 20 μm, there is a fear that the accuracy of forming the tapered protruding portion 1523 is lowered, and if it is larger than 120 μm, the latent heat for heating the heating portion 1521 itself is generated. It becomes too large, and there is a concern that the amount of heat is reduced relative to the amount of electricity. Therefore, by setting the thickness dimension and the width dimension of the cross section of the heating portion 1521 to the above-described desired range, the heat generation efficiency of the heating portion 1521 can be improved. Further, among the cross sections of the heating portion 1521, the magnitude relationship between the thickness dimension and the width dimension is not specifically limited. The ratio of the thickness dimension of the heating portion 1521 to the width dimension (aspect ratio) is as large as about 1:2, and can be manufactured by double-sided etching.

<Modification>

In addition, the setting example of the metal heater 152 shown in FIG. 8 is The heating portion 1521 is provided in a state where the back surface S2 of the hot portion 1521 abuts (contacts) the liquid holding member 151, but is not limited thereto. The metal heater 152 can also be provided in a state where the surface S1 of the heating portion 1521 abuts (contacts) the liquid holding member 151. For example, the metal heater 152 can also be provided in a state in which a part of the heating portion 1521 is buried in the liquid holding member 151. For example, in the modification shown in FIG. 9A, the metal heater 152 and the liquid holding member 151 can be made such that the front end FE of the tapered protruding portion 1523 of the heating portion 1521 contacts the surface 151a of the liquid holding member 151. At least one of them is forced. When the heating portion 1521 is caught in the liquid holding member 151 until the front end FE of the tapered protruding portion 1523 of the heating portion 1521 is in contact with the surface 151a of the liquid holding member 151, the mist generating liquid held in the liquid holding member 151 is smoothly passed. The point of atomization is appropriate.

Further, as in the modification shown in FIG. 9B, the surface of the heating portion 1521 may be exposed to the outside, and the entire heating portion 1521 may be buried in the liquid holding member 151 to keep the metal heater 152 and the liquid. At least one of the members 151 is biased. When the metal heater 152 is provided in such a manner, it is particularly preferable from the viewpoint of promoting atomization of the mist generating liquid. In the example shown in FIG. 9B, the metal heater 152 is provided in a state where the surface S1 of the heating portion 1521 is located lower than the surface 151a of the liquid holding member 151. Further, in the modification shown in FIG. 9C, for example, at least one of the metal heater 152 and the liquid holding member 151 may be biased to thereby form a tapered shape of the side surface S3 of the heating portion 1521 of the metal heater 152. The protruding portion 1523 abuts (contacts) the liquid holding member The metal heater 152 is provided in the posture of 151.

According to the arrangement shown in FIG. 9C, when the atomizing unit 15 is to be assembled at the time of manufacture of the mist absorbing device 1, the tapered protruding portion 1523 of the heating portion 1521 of the metal heater 152 is locked to the liquid holding member. The anchoring effect produced by 151 can also improve the assembly accuracy of the metal heater 152.

<Embodiment 2>

Next, the second embodiment will be described. 10A and 10B are schematic views of the metal heater 152 of the second embodiment. Fig. 10A shows the plane of the metal heater 152, and Fig. 10B shows the side of the metal heater 152.

The metal heater 152 of the present embodiment is a plate heater having a plate-shaped heating portion 1521A. In the example shown in FIG. 10A, the heating portion 1521A has a substantially rectangular plane, and a plurality of through holes 1524 are formed through the heating portion 1521A in the thickness direction. Hereinafter, the longitudinal direction among the planes of the heating portion 1521A is referred to as a longitudinal direction, and the short-side direction is referred to as a width direction. In the example shown in FIG. 10A, the through hole 1524 has a rectangular cross section, and a plurality of through holes 1524 are aligned in a lattice shape in the plane of the heating portion 1521A.

Similarly to the linear heating portion 1521 of the first embodiment, the heating portion 1521A of the metal heater 152 of the second embodiment has a surface S1 and a back surface S2 facing the surface S1. Further, it has four side faces S3 that connect the surface S1 and the back surface S2. Fig. 11 is a partial schematic cross-sectional view showing the heating portion 1521A of the second embodiment. Heating section 1521A shown in Fig. 11 The cross section is a cross section when the heating portion 1521 is cut along the width direction (short side direction).

In the heating unit 1521A of the present embodiment, the tapered protruding portion 1523 described in the first embodiment is provided on each side surface S3. In the present embodiment, the tapered protruding portion 1523 is also formed by a pair of first tapered surface TS1 and second tapered surface TS2 which are formed in a concave curved shape, and are orthogonal to the imaginary line L1 from the surface S1 toward the back surface S2. The direction is set. Further, the first tapered surface TS1 is formed with a concave curved surface toward the front end FE of the tapered protruding portion 1523 with the front side edge portion E1 connecting the front surface S1 and the side surface S3 as a base end, and the second tapered surface TS2 is connected to the back surface S2. The back side edge portion E2 of the side surface S3 is a base end and is formed in a concave curved shape toward the front end FE of the tapered protrusion portion 1523. The tapered protrusion 1523 extends along the four side faces S3 and is formed in a ring shape so as to surround the outer circumference of the heating portion 1521A. In the present embodiment, the front end FE of the tapered protruding portion 1523 of the heating portion 1521A is also located substantially at the center in the thickness direction of the heating portion 1521A.

Here, the symbol S3' shown in Fig. 11 is the inner peripheral side surface of the through hole 1524. The inner circumferential side surface S3' of the through hole 1524 of the heating portion 1521A corresponds to the side surface of the connection surface S1 and the back surface S2. As shown in Fig. 11, the heating portion 1521A of the present embodiment is also provided with a tapered protruding portion 1523A on the inner circumferential side surface S3' of the through hole 1524. The tapered projection 1523A is formed by the first tapered surface TS1' and the second tapered surface TS2'. The first tapered surface TS1' has a front side FE that is connected to the surface S1 of the heating portion 1521A and the front side surface portion S3' as a base end, and forms a concave curved surface toward the front end FE of the tapered protruding portion 1523A. The second tapered surface The TS2' is connected to the back side S2 and the inner peripheral side S3' The back side edge portion E2' is a base end and is formed in a concave curved shape toward the front end FE of the tapered protruding portion 1523A. The tapered projection 1523A is formed in an annular shape along the inner circumferential side surface S3', and its front end FE is located substantially at the center in the thickness direction of the heating portion 1521A.

The metal heater 152 of the second embodiment can be suitably produced by double-sided etching processing of the metal base material BM1 described in the first embodiment. The etching process for the metal base material BM1 is the same as that of the first embodiment, and detailed description thereof will be omitted.

Fig. 12 is a view showing the relationship between the liquid holding member 151 and the metal heater 152 in the atomizing unit 15 of the second embodiment. In the example shown in FIG. 12, the heating unit 1521A is provided in a state in which the back surface S2 (which may be the surface S1) of the heating portion 1521A having a flat plate shape is in contact with (contacted with) the liquid holding member 151. In the present embodiment, the tapered projection 1523 is formed also on the side surface S3 of the heating portion 1521A, and the tapered projection 1523A is formed on the inner circumferential side surface S3 of the through hole 1524. Therefore, the surface area of the heating portion 1521A can be increased. In other words, when the comparison is made in the same sectional area, since the tapered protruding portions 1523 and 1523A are provided, the surface area of the heating portion 1521A can be increased relative to the case where the tapered protruding portion is not provided. As a result, the vaporization of the mist generating liquid can be promoted by the heat generation of the heating portion 1521A at the time of energization, and the mist can be efficiently generated.

Further, according to the atomization unit 15 of the present embodiment, the metal heater 152 is provided in a state in which the back surface S2 of the flat heating portion 1521 arranged in a lattice shape in the through hole 1524 is in surface contact with the liquid holding member 151. Therefore, the liquid suction can be maintained by the capillary force. The mist generating liquid of the holding member 151 is sucked into the inside of each of the through holes 1524 in the heating portion 1521A. In particular, since each of the through holes 1524 of the heating portion 1521A is provided with the tapered protruding portion 1523A, the back side edge portion E2 submerged to the base end of the second tapered surface TS2 to be formed into a concave curved surface by capillary force is formed. The structure in which the opening cross-sectional area of the through hole 1524 gradually decreases toward the front end FE. Thereby, the mist generating liquid can be smoothly sucked from the liquid holding member 151 toward the distal end FE along the second tapered surface TS2' of the tapered protruding portion 1523A provided in each of the through holes 1524 of the heating portion 1521A. In other words, when the heating portion 1521A is energized, it can be vaporized while being sucked up along the second tapered surface TS2' of the tapered protruding portion 1523A.

Further, in each of the through holes 1524 of the heating portion 1521A, the opening cross-sectional area of the through hole 1524 gradually increases from the vicinity of the center in the thickness direction where the front end FE of the tapered protruding portion 1523A is located to the front side edge portion E1'. structure. Therefore, the mist generating liquid vaporized by the heating of the second tapered surface TS2' of the tapered projection 1523A can be smoothly diffused toward the atomizing space 153. As a result, the vaporized mist generating liquid can be effectively mixed with the air in the atomizing space 153, and the generation of the mist is promoted.

Further, in the atomization unit 15 of the present embodiment, the metal heater 152 can be provided in such a manner that the surface S1 of the heating portion 1521A abuts (contacts) the liquid holding member 151. In this case, it is also expected to be provided by The effect of promoting the generation of mist as described above generated by the tapered projection 1523A of the through hole 1524. Further, in the heating portion 1521A of the present embodiment, the arrangement relationship with the liquid holding member 151 described in the modification of the ninth to eighth embodiments can be employed.

Further, the shape of the through hole 1524 of the heating portion 1521A is not specifically limited, and may be a circular cross section or a polygonal shape other than a square shape. Further, in the example shown in FIG. 10A, a plurality of through holes 1524 are arranged in a lattice shape in the heating portion 1521A, but the arrangement of the through holes 1524 is not specifically limited. For example, a plurality of through holes 1524 may be arranged in an irregular shape in the heating portion 1521A.

Further, the dimension of the longitudinal direction (longitudinal direction) of the heating portion 1521A of the metal heater 152 of the second embodiment is not specifically limited, but may be generally 15 mm or less.

Although the preferred embodiment of the present invention has been described above, various modifications, improvements, combinations, and the like can be made to the metal heater for the mist suction device, the mist suction device, and the mist suction device of the embodiment. For example, the heating unit 1521 (see FIG. 3 and the like) shown in the first embodiment or the heating unit 1521A (see FIG. 11 and the like) shown in the second embodiment is displayed in a direction toward and from the surface S1. The direction in which the imaginary line L1 of the back surface S2 is orthogonal may cause the tapered protruding portion 1523 to protrude. However, the tapered protruding portion 1523 may protrude in different directions with respect to the imaginary line L1, and may be inclined with respect to the imaginary line L1, for example. The direction of the direction causes the tapered protrusion 1523 to protrude.

Claims (13)

A mist suction device includes: a liquid storage unit that stores a mist generation liquid; and a sheet-shaped metal heater that atomizes a mist generation liquid supplied from the liquid storage unit; the metal heater has a surface, a back surface facing the front surface, and a side surface connecting the front surface and the back surface, wherein at least a portion of the side surface is provided with a tapered protruding portion that faces an imaginary line from the front surface toward the back surface The tapered protrusion protrudes in a different direction, and the tapered protrusion has a first tapered surface that is formed in a concave curved shape toward a distal end of the tapered protruding portion with a front side edge portion connected to the front surface and the side surface as a base end; A second tapered surface having a concave curved surface is formed at a front end of the tapered side portion with the back side edge portion connecting the back surface and the side surface as a base end. In the mist suction device according to the first aspect of the invention, the protruding end length of the tapered end portion from the base end to the front end is 5% or more and 20% or less with respect to the thickness dimension of the metal heater. In the mist suction device according to the first aspect of the invention, the front end of the tapered projection is substantially at the center in the thickness direction of the metal heater. The mist suction as described in any one of claims 1 to 3 In the above-described metal heater, a heating portion and an electrode portion that generate heat during energization and heat the mist generating liquid are integrally formed. The sputum for a mist absorbing device according to any one of claims 1 to 4, wherein the metal heater is a linear heater having a line shape. The sputum for a mist absorbing device according to any one of claims 1 to 4, wherein the metal heater is a plate heater having a plate shape. The mist for a mist suction device according to claim 6, wherein a through hole penetrating the metal heater in a thickness direction is provided, and the tapered projection is provided on an inner circumferential side surface of the through hole. The mist suction device according to claim 7, wherein the plurality of through holes are arranged in the metal heater. The mist suction device according to any one of claims 1 to 8, further comprising: a supply between the liquid storage portion and the metal heater, and maintaining the supply from the liquid storage portion A liquid holding member for the mist generating liquid, wherein the metal heater is provided in contact with the liquid holding member. The sputum for a mist suction device according to claim 9, wherein the metal heater is a plate heater having a plate shape, and the front surface or the back surface is provided in contact with the liquid holding member. The metal heater is provided with a plurality of through holes penetrating in the thickness direction, and the tapered projections are provided on the inner circumferential side faces of the respective through holes. A mist suction device for use in a mist suction device according to any one of claims 1 to 10. A mist suction device comprising: a liquid storage portion for storing a mist generating liquid; and a sheet-shaped metal heater for atomizing a mist generating liquid supplied from the liquid storage portion; the metal heater having a surface a back surface facing the surface and a side surface connecting the front surface and the back surface, wherein at least a portion of the side surface is provided with a tapered protruding portion that is different from an imaginary line from the surface toward the back surface The tapered protruding portion has a first tapered surface having a concave curved surface formed at a front end of the tapered protruding portion with a front side edge portion connecting the front surface and the side surface as a base end; A second tapered surface having a concave curved surface is formed at a front end of the tapered side portion with the back side edge portion connecting the back surface and the side surface as a base end. A metal heater for a mist suction device is a sheet-shaped metal heater for mist mist suction that atomizes a mist generating liquid, and the metal heater for a mist suction device has a surface, a back surface facing the surface, and a connection a side surface of the front surface and the back surface; and at least a portion of the side surface is provided with a tapered protruding portion, The tapered protruding portion protrudes in a tapered shape in a direction different from an imaginary line from the front surface toward the back surface, and the tapered protruding portion has a front side edge portion connected to the front surface and the side surface as a base end and faces the front side a front end of the tapered protruding portion forms a first tapered surface having a concave curved surface; and a second tapered surface having a concave curved surface formed by a front end portion connecting the back surface and the side surface as a base end and facing the front end of the tapered protruding portion .