Heaters and hair irons

Abstract

This heater comprises a ceramic body, a heat generation resistor, and a bimetal switch. The ceramic body has: a first surface; and a second surface located opposite to the first surface. The heat generation resistor is located inside the ceramic body, and has a first resistor and a second resistor. The bimetal switch is located between the first resistor and the second resistor.

Description

[Technical Field]

[0001] The disclosed embodiments relate to a heater and a hair iron. [Background technology]

[0002] 2. Description of the Related Art A heater having a heating resistor inside a ceramic body is known, and such a heater is used in electric heating appliances such as hair irons. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-245729 Summary of the Invention

[0004] A heater according to one aspect of the embodiment includes a ceramic body, a heating resistor, and a bimetal switch. The ceramic body has a first surface and a second surface opposite the first surface. The heating resistor is located within the ceramic body and includes a first resistor and a second resistor. The bimetal switch is located between the first resistor and the second resistor. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 is a perspective view showing a heater according to an embodiment. [Figure 2] FIG. 2 is an exploded perspective view showing an example of a heater according to the embodiment. [Figure 3] FIG. 3 is a plan view showing the heater according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view taken along line AA shown in FIG. [Figure 5] FIG. 5 is an enlarged view of region B shown in FIG. [Figure 6] FIG. 6 is a cross-sectional view showing another example of a heater according to an embodiment. [Figure 7]FIG. 7 is a perspective view showing another example of the heater according to the embodiment. [Figure 8] FIG. 8 is a cross-sectional view of the heater shown in FIG. [Figure 9] FIG. 9 is a perspective view showing another example of the heater according to the embodiment. [Figure 10] FIG. 10 is a cross-sectional view of the heater shown in FIG. [Figure 11] FIG. 11 is a cross-sectional view showing another example of a heater according to the embodiment. [Figure 12] FIG. 12 is a perspective view showing another example of a heater according to the embodiment. [Figure 13] FIG. 13 is a cross-sectional view of the heater shown in FIG. [Figure 14] FIG. 14 is a plan view showing another example of the heater according to the embodiment. [Figure 15] FIG. 15 is a plan view showing another example of the heater according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0006] Such heaters are sometimes used with fuses that cut off current when an abnormal temperature rise occurs. However, since a fuse that has cut off current cannot be reused and must be replaced, there is a need to improve user convenience.

[0007] Furthermore, when the fuse is mounted so that it is in contact with the heater surface, if the contact with the heater is poor, the temperature may be detected as low, which could result in the heater overheating.Even if the contact is accurate, if the heater heats up rapidly, if the heat dissipation around the heater is poor, or if the heater heats up locally, the fuse's detection speed cannot keep up with the heater's temperature rise rate, and the fuse may detect the temperature as low as possible, which could result in the heater overheating.

[0008] Therefore, there is a need for a heater and a hair iron that can improve user convenience.

[0009] Hereinafter, embodiments of the heater and hair iron disclosed in the present application will be described with reference to the accompanying drawings. Note that the present disclosure is not limited to the embodiments shown below. It should be noted that the drawings are schematic, and the dimensional relationships between elements, the ratios of elements, etc. may differ from reality.

[0010] <Embodiment> First, a heater according to an embodiment will be described with reference to Figures 1 to 5. Figure 1 is a perspective view showing a heater according to an embodiment.

[0011] 1, the heater 1 according to the embodiment includes a bimetal switch 10, a first substrate 20, a second substrate 30, a heating resistor 31, and a pair of lead wires 40. The heater 1 is configured so that the state of electrical current flowing to the heating resistor 31, which is electrically connected to the pair of lead wires 40, can be switched by the bimetal switch 10 located on a first surface 1a, which is the surface of the heater 1. The heater 1 is used, for example, in a hair iron or the like.

[0012] For ease of understanding, Fig. 1 illustrates a three-dimensional Cartesian coordinate system including a Z axis extending along the thickness direction of the heater 1. Such a Cartesian coordinate system is also shown in other drawings used in the following description.

[0013] Fig. 2 is an exploded perspective view showing an example of a heater according to an embodiment, Fig. 3 is a plan view showing the heater according to an embodiment, and Fig. 4 is a cross-sectional view taken along line AA shown in Fig. 3.

[0014] The bimetal switch 10 has a fixed portion 13 and bimetal portions 11 and 12. The fixed portion 13 is fixed to the surface of the heater 1. The fixed portion 13 can be made of a heat-resistant material, such as a phenolic resin, a polyphenylene sulfide resin, or a ceramic material such as alumina. The fixed portion 13 may be fixed to the first surface 1a of the heater 1 by, for example, a bonding material.

[0015] The bimetal portions 11 and 12 are, for example, plate-shaped members, and are laminated bodies made of two types of metal materials with different thermal expansion coefficients. The laminate may have, for example, a high-expansion layer made of an iron-nickel alloy containing small amounts of Cr, Mn, Mg, etc., and a low-expansion layer made of Invar.

[0016] For example, when the bimetal switch 10 reaches a predetermined temperature or higher, the bimetal parts 11 and 12 deform so as to separate their contacts with pads 21 and 22 (described later). As a result, the bimetal parts 11 and 12 stop the flow of electricity to the heating resistor 31 via the lead wire 40. Furthermore, for example, when the bimetal switch 10 falls below a predetermined temperature, the bimetal parts 11 and 12 deform so as to come into contact with the pads 21 and 22. As a result, the bimetal parts 11 and 12 resume the flow of electricity to the heating resistor 31. In other words, the bimetal parts 11 and 12 repeatedly make contact with and separate from the pads 21 and 22 in response to temperature changes in the heater 1.

[0017] For example, if the heater 1 thermally expands with a rise in temperature while the bimetal parts 11, 12 and the pads 21, 22 are in contact and conducting, even if the contact points are slightly misaligned due to the difference in thermal expansion, stress caused by the difference in thermal expansion is unlikely to concentrate. Therefore, even if the heater 1 is used for a long period of time, the contact points between the bimetal parts 11, 12 and the pads 21, 22 are unlikely to break, and the detection sensitivity is unlikely to decrease.

[0018] The first substrate 20 has a ceramic body 201, pads 21 and 22, vias 23 and 24, and a recess 25. The ceramic body 201 is a flat plate-shaped member having a first surface 20a and a second surface 20b. The first surface 20a is located on the surface of the heater 1 and also serves as the first surface 1a (see FIG. 1). The second surface 20b is located on the opposite side to the first surface 20a and faces the second substrate 30.

[0019] The material of the ceramic body 201 is, for example, an insulating ceramic. For example, oxide ceramics, nitride ceramics, or carbide ceramics can be used as the material of the ceramic body 201. Specifically, alumina ceramics, silicon nitride ceramics, aluminum nitride ceramics, silicon carbide ceramics, etc. can be used as the material of the ceramic body 201.

[0020] The pads 21 and 22 are located on the first surface 20a of the ceramic body 201. The pads 21 and 22 are located so as to overlap the vias 23 and 24 in a plan view. The pads 21 and 22 are in contact with the bimetal portions 11 and 12 of the bimetal switch 10. The spacing and size of the pads 21 and 22 are set, for example, depending on the shape of the bimetal switch 10. The pads 21 and 22 can be made of a metal material such as tungsten.

[0021] The vias 23 and 24 extend in the thickness direction of the first substrate 20, and are positioned so that one end is exposed on the second surface 20b. The other ends of the vias 23 and 24 are electrically connected to the pads 21 and 22.

[0022] The vias 23 and 24 may, for example, have the same material as the pads 21 and 22. The vias 23 and 24 may also contain, for example, molybdenum, copper, silver, nickel, or the like.

[0023] The recess 25 is located so as to contact an end face 20c located at one end in the longitudinal direction of the ceramic body 201. The recess 25 is open so as to penetrate through the first surface 20a and the second surface 20b of the first substrate 20. The recess 25 accommodates a lead wire 40 fixed with a bonding material.

[0024] The second substrate 30 has a ceramic body 301, a heating resistor 31, terminals 31a and 31b, and a conductor 32. The ceramic body 301 is a flat plate-shaped member having a first surface 30a and a second surface 30b. The first surface 30a faces the first substrate 20. The second surface 20b is located on the opposite side to the first surface 30a and also serves as the second surface 1b (see FIG. 8) of the heater 1. Hereinafter, the ceramic bodies 201 and 301 may be collectively referred to as the ceramic body 2.

[0025] The heating resistor 31 is located on the ceramic body 301. The heating resistor 31 is a member that generates heat when a current flows through it. The heating resistor 31 forms a heat generating region 35 on the other end side in the longitudinal direction of the heater 1 (the negative X-axis direction side). The heating resistor 31 may include a high-resistance conductor containing, for example, tungsten, molybdenum, or the like.

[0026] The heating resistor 31 has a first resistor 311 and a second resistor 312. One end of the first resistor 311 is connected to the terminal 31a, and the other end is connected to the first conductor 32a of the conductor 32. The second resistor 312 has one end connected to the terminal 31b, and the other end is connected to the second conductor 32b of the conductor 32. The shapes of the first resistor 311 and the second resistor 312 are not limited to those shown in the figure, and can be changed as appropriate depending on, for example, the heat generation characteristics required of the heater 1.

[0027] The terminals 31a and 31b are located directly below the vias 23 and 24 and are electrically connected to the vias 23 and 24. The material of the terminals 31a and 31b may be the same as that of the heating resistor 31, for example.

[0028] The conductor 32 is electrically connected to the heating resistor 31. The conductor 32 has a first conductor 32a and a second conductor 32b. The first conductor 32a is connected to the first resistor 311 and to the first lead 41 of the lead wire 40 via a bonding material. The second conductor 32b is connected to the second resistor 312 and to the second lead 42 of the lead wire 40 via a bonding material. The conductor 32 is positioned so as to overlap the recess 25 in a plan view. The conductor 32 may be made of, for example, a metal material containing tungsten, molybdenum, or the like, or may be plated with a metal material such as nickel. The material of the conductor 32 may be the same as or different from that of the heating resistor 31. Note that, as a bonding material for joining the conductor 32 to the lead wire 40, for example, a brazing material such as solder or silver solder may be used.

[0029] The lead wire 40 is a wire containing a metal material such as nickel, iron, or a nickel-based heat-resistant alloy. The lead wire 40 is drawn out from the recess 25 to the outside of the heater 1. The cross section of the lead wire 40 may be, for example, circular, elliptical, or rectangular. The outer diameter of the lead wire 40 may be, for example, 0.5 to 2.0 mm.

[0030] The lead wire 40 has a first lead 41 and a second lead 42. The first lead 41 is connected to the first resistor 311. The second lead 42 is connected to the second resistor 312. The first lead 41 and the second lead 42 are electrically connected to an external power supply.

[0031] Next, the heater 1 according to the embodiment will be further described with reference to Figures 4 and 5. Figure 5 is an enlarged view of region B shown in Figure 4.

[0032] 4, the pads 21 and 22 may be located directly above the vias 23 and 24, respectively. The vias 23 and 24 have higher thermal conductivity than the ceramic body 2, and therefore are more likely to reflect an excessive temperature rise inside the heater 1. If the pads 21 and 22, which are contact points of the bimetal switch 10, are located directly above the vias 23 and 24, for example, the response to an excessive temperature rise will be increased.

[0033] Furthermore, the pads 21 and 22 may protrude from the first surface 20a toward the bimetal portions 11 and 12 of the bimetal switch 10. This makes it easier to ensure electrical continuity, except when an excessive temperature rise is detected, because the pads 21 and 22 are located higher than the first surface 20a, even if the ceramic body 2 is deformed due to thermal expansion.

[0034] 5, the bimetal part 12 of the bimetal switch 10 may have a contact part 12a that protrudes toward the pad 22. The pad 22 may also have a recessed receiving part 22a that receives the contact part 12a. This increases the contact area between the bimetal part 12 and the pad 22, making it easier to ensure electrical continuity even if the ceramic body 2 is deformed due to thermal expansion, for example, except when an overheating is detected.

[0035] <Another embodiment> 6 is a cross-sectional view showing another example of the heater according to the embodiment. As shown in FIG. 6, the pad 22 may have a first layer 221 located on the first surface 20a (see FIG. 4) and a second layer 222 located on the first layer 221.

[0036] The second layer 222 may have a lower hardness than the first layer 221. The second layer 222 may have a recessed receiving portion 22a that receives the contact portion 12a. This is expected to increase the contact area by pressing the bimetal portion 12 against the pad 22, and therefore, even if the ceramic body 2 is deformed due to thermal expansion, for example, electrical continuity is more easily ensured except when an excessive temperature rise is detected.

[0037] Here, the material of the first layer 221 may be, for example, tungsten. The material of the second layer 222 may be, for example, nickel, a tin-nickel alloy, or a gold-nickel alloy. The pad 22 may also be formed by stacking three or more layers.

[0038] 5 and 6, the bimetal part 12 and pad 22 of the bimetal switch 10 have been described as an example, but the bimetal part 11 and pad 21 may also be configured in the same way.

[0039] Fig. 7 is a perspective view showing another example of a heater according to the embodiment, and Fig. 8 is a cross-sectional view of the heater shown in Fig. 7.

[0040] As shown in FIGS. 7 and 8, the heater 1 may further include a clamping member 50.

[0041] The clamping member 50 has clamping pieces 51 and 52. The clamping piece 51 has a first portion 51a, a second portion 51b, and a third portion 51c. The first portion 51a is in contact with the fixed portion 13 of the bimetal switch 10 so as to press it against the first substrate 20. The third portion 51c is in contact with the second substrate 30 so as to press the second surface 1b of the heater 1. The second portion 51b is located between the first portion 51a and the third portion 51c, and is located opposite the side surface 1c of the heater 1. The second portion 51b may be in contact with the side surface 1c or may be separated from it.

[0042] The clamping piece 52 has a first portion 52a, a second portion 52b, and a third portion 52c. The first portion 52a contacts the fixing portion 13 so as to press it against the first substrate 20. The third portion 52c contacts the second substrate 30 so as to press the second surface 1b of the heater 1. The second portion 52b is located between the first portion 52a and the third portion 52c, and faces the side surface 1d of the heater 1. The second portion 52b may be in contact with the side surface 1d or may be separated from it.

[0043] The material of the clamping member 50 may be, for example, stainless steel. The clamping member 50 may fix the bimetal switch 10 by, for example, sandwiching the bimetal switch 10 and the ceramic body 2 together. By sandwiching the bimetal switch 10 and the ceramic body 2 together, it becomes easier to fix the bimetal switch 10 directly to the first surface 1a of the ceramic body 2 without using, for example, a bonding material. This makes it difficult for heat to dissipate through the bonding material, making it easier to detect an overheating. Note that the clamping member 50 may be fixed to the first surface 1a via, for example, a bonding material.

[0044] Fig. 9 is a perspective view showing another example of a heater according to the embodiment. Fig. 10 is a cross-sectional view of the heater shown in Fig. 9. As shown in Figs. 9 and 10, the clamping member 50 shown in Fig. 8 may be configured to cover the entire first substrate 20 and the second substrate 30.

[0045] The clamping member 50 may have a first portion 50a, a second portion 50b, a third portion 50c, a fourth portion 50d, and a fifth portion 50e. The first portion 50a and the fifth portion 50e, located at both ends of the clamping member 50, each press the fixed portion 13 of the bimetal switch 10 toward the first substrate 20. The third portion 50c contacts the second substrate 30 so as to press the second surface 1b of the heater 1. The second portion 50b is located between the first portion 50a and the third portion 50c and faces the side surface 1c of the heater 1. The fourth portion 50d is located between the third portion 50c and the fifth portion 50e and faces the side surface 1d of the heater 1. The second portion 50b and the fourth portion 50d may contact or be separated from the side surfaces 1c and 1d, respectively.

[0046] 9 and 10 may function as a case for housing the ceramic body 2 and the bimetal switch 10. This prevents stress from being applied to the bimetal switch 10, even if the contact points between the bimetal switch 10 and the pads 21 and 22 are misaligned due to differences in thermal expansion at various locations within the heater 1, thereby improving durability. Furthermore, the bimetal switch 10 detects excessive temperature rise inside the clamping member 50, which serves as a case, thereby improving detection accuracy, for example.

[0047] 11 is a cross-sectional view showing another example of the heater according to the embodiment. As shown in FIG. 11, the heater may further include a pressing member 60 located on the bimetal switch 10 shown in FIG.

[0048] The pressing member 60 may be made of a heat-resistant material, such as a resin such as phenolic resin or polyphenylene sulfide resin. Alternatively, the pressing member 60 may be made of a ceramic material such as alumina. The pressing member 60 may also be made of a metal material such as nickel, iron, or a nickel-based heat-resistant alloy. For example, the clamping member 50 may not contact the bimetal switch 10, but may press indirectly via the pressing member 60. This improves the durability of the bimetal switch 10.

[0049] Fig. 12 is a perspective view showing another example of a heater according to the embodiment. Fig. 13 is a cross-sectional view of the heater shown in Fig. 12. As shown in Figs. 12 and 13, the pressing member 60 that presses the bimetal switch 10 may have a width in the Y-axis direction greater than that of the fixed portion 13.

[0050] The pressing member 60 may have a first region 61 that contacts the fixed portion 13 of the bimetal switch 10, and a second region 62 that does not contact the fixed portion 13. The first portion 50a and the fifth portion 50e of the clamping member 50 may be positioned so as to contact the second region 62 of the pressing member 60. This allows the pressing member 60 to bend like a spring and fix the bimetal switch 10, even if the ceramic body 2 is deformed due to thermal expansion, for example. This improves the durability of the bimetal switch 10.

[0051] Fig. 14 is a plan view showing another example of a heater according to the embodiment, in which the bimetal switch 10 and the first substrate 20 are omitted.

[0052] As shown in FIG. 14, the heater 1 may further include a resistance temperature detector 33 and a conductor .

[0053] The resistance temperature detector 33 is located on the first surface 30a of the second substrate 30. The resistance temperature detector 33 is arranged next to the first resistor 311 and the second resistor 312. The resistance temperature detector 33 is connected to lead wires 43 and 44 via a conductor 34.

[0054] The conductor 34 has a first conductor 34a and a second conductor 34b. The first conductor 34a and the second conductor 34b are positioned with a predetermined distance between the first conductor 32a and the second conductor 32b. One end of the resistance temperature detector 33 is connected to the first conductor 34a and the other end is connected to the second conductor 34b. The first conductor 34a is connected to a lead wire 43, and the second conductor 34b is connected to a lead wire 44.

[0055] The resistance temperature detector 33 may be, for example, a temperature sensor for controlling the internal temperature of the heater 1. The material of the resistance temperature detector 33 may be, for example, a high-resistance conductor including tungsten, molybdenum, or platinum. The resistance temperature detector 33 can detect the temperature of the entire heater 1 and control the temperature of the heater 1. For example, by controlling the temperature with the resistance temperature detector 33 and detecting an overheating with the bimetal switch 10, user convenience is improved.

[0056] Fig. 15 is a plan view showing another example of the heater according to the embodiment. As shown in Fig. 15, a resistance temperature detector 33 may be located in an inter-terminal region 31c between terminals 31a and 31b of the heater 1 shown in Fig. 14.

[0057] The resistance temperature detector 33 may have an inter-terminal portion 33a located in the inter-terminal region 31c. The inter-terminal portion 33a may be repeatedly bent with respect to a first direction along the X-axis so as to extend in a second direction along the Y-axis direction intersecting the X-axis. This positions the resistance temperature detector 33 directly below the bimetal switch 10, thereby improving the detection accuracy of the resistance temperature detector 33.

[0058] Furthermore, the cross-sectional area of the inter-terminal portion 33a of the resistance temperature detector 33 may be smaller than the cross-sectional area of the portion other than the inter-terminal portion 33a. This improves the detection accuracy of the resistance temperature detector 33 directly below the bimetal switch 10.

[0059] As described above, the heater 1 according to this embodiment includes the ceramic body 2, the heating resistor 31, and the bimetal switch 10. The ceramic body 2 has a first surface 1a and a second surface 1b located opposite the first surface 1a. The heating resistor 31 is located inside the ceramic body 2 and has a first resistor 311 and a second resistor 322. The bimetal switch 10 is located between the first resistor 311 and the second resistor 312 and switches the state of conduction to the heating resistor 31. This improves user convenience.

[0060] The hair iron according to the embodiment includes the heater 1 described above. This makes it difficult for the heater 1 to overheat and allows for stable use over a long period of time, making it possible to provide an excellent hair iron that does not damage hair, for example.

[0061] Further advantages and other aspects may readily occur to those skilled in the art. Therefore, the disclosure in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. [Explanation of symbols]

[0062] 1 heater 2 ceramic body 10 Bimetal Switch 20 First board 21,22 Pads 23,24 Via 30 Second board 31 Heating resistor 40 lead wire 50 Clamping member 60 Pressing member

Claims

1. A ceramic body; A heating resistor; A bimetal switch, Resistance thermometer and Equipped with the ceramic body has a first surface and a second surface opposite the first surface; the heating resistor is located inside the ceramic body and has a first resistor and a second resistor; the bimetal switch is located between the first resistor and the second resistor; the resistance temperature detector is located inside the ceramic body so as to be aligned with the first resistor and the second resistor, The resistance temperature detector is located between the terminals of the first resistor and the second resistor arranged in a first direction, and has an inter-terminal portion that is repeatedly bent so as to extend along a second direction that intersects the first direction. heater.

2. a pair of pads located on the first surface of the ceramic body and electrically connected to the first resistor and the second resistor through vias; The bimetal switch is positioned so as to be able to come into contact with and separate from each of the pair of pads. The heater of claim 1 .

3. The pad protrudes from the first surface of the ceramic body. The heater according to claim 2 .

4. The pad has a first layer positioned on the ceramic body and a second layer positioned on the first layer and having a hardness less than that of the first layer. The heater according to claim 2 .

5. The bimetal switch has a contact portion that protrudes toward the pad, The pad has a recessed receiving portion that receives the contact portion. The heater according to claim 2 .

6. The ceramic body further includes a clamping member that clamps the bimetal switch and the second surface of the ceramic body, the second surface being located on the opposite side to the first surface of the ceramic body on which the bimetal switch is located. The heater of claim 1 .

7. The clamping member accommodates the ceramic body and the bimetal switch. The heater according to claim 6.

8. a pressing member facing the first surface across the bimetal switch, The pressing member has a first region that contacts the bimetal switch and a second region that contacts the clamping member but does not contact the bimetal switch. The heater according to claim 6.

9. The cross-sectional area of the portion between the terminals of the resistance thermometer sensor is smaller than the cross-sectional area of the portion other than the portion between the terminals. The heater of claim 1 .

10. A hair iron comprising the heater according to any one of claims 1 to 9.

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