Toothbrush

Abstract

Provided is a toothbrush capable of effectively heating gingiva by uniformly heating the entire head without causing a heating element to excessively heat. This toothbrush is provided with: a head part having a brush part; a grip section positioned on the rear end side of the head section; the heat conductor is at least arranged on the head part, and the heat conductivity coefficient of the heat conductor is larger than that of the head part; and a heat-generating body that is provided in contact with the heat-conducting body and generates heat when energized.

Description

TECHNICAL FIELD

[0001] The present application relates to a toothbrush.

[0002] This application claims priority from Japanese Patent Application No. 2023-123789 filed on July 28, 2023, the contents of which are incorporated herein by reference. BACKGROUND

[0003] A technique of preventing periodontal disease by heating a gingiva is known.

[0004] A toothbrush provided with a heating element in a head portion is disclosed in Patent Literature 1. In the toothbrush disclosed in Patent Literature 1, it is described that the head portion is warmed to a desired temperature by heat emitted from the heating element, and the warmed bristles and the tip of the head portion are brought into contact with the gingiva at the time of tooth brushing, whereby heat energy is transmitted to the gingiva to promote blood circulation of the gingiva.

[0005] Prior art documents

[0006] Patent documents

[0007] Patent Literature 1: Japanese Patent Application Publication No. 2001-137046 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] In the case of warming the head portion of the toothbrush, it is necessary to warm to the target temperature immediately after the operation in view of the usability. Since the amount of electricity that can be mounted in the toothbrush is limited, as a countermeasure, it is considered to provide the heating element as a small heating element, and concentrate the electric power to this to heat rapidly.

[0010] However, in the case where the head portion is heated with a small heating element using a resin having a poor thermal conductivity, the heat emitted from the heating element is difficult to spread to the entire head portion, and the heating range becomes local. Therefore, the range of warming to the target temperature becomes limited, and there is a problem that the gingiva cannot be efficiently warmed.

[0011] Further, in the case of heating the entire head portion, it is necessary to make the heating element excessively heat, and therefore there is a problem in the electric power and safety. Then, it is considered to provide the heating element to the entire head portion, but since the amount of electricity that can be mounted in the toothbrush is limited, it takes time until the heating element provided to the entire head portion is warmed, and there is a problem in the usability.

[0012] The present application has been achieved in view of the above, and an object thereof is to provide a toothbrush that does not excessively heat the heating element, warms the entire head portion uniformly, and can efficiently heat the gingiva.

[0013] Solutions for solving the problem

[0014] The present application has the following solutions.

[0015] [1] A toothbrush characterized by comprising: a head portion having a brush portion; a grip portion provided at a rear end side of the head portion; a heat conductor provided at least at the head portion, the heat conductor having a thermal conductivity greater than that of the head portion; and a heat generator provided in contact with the heat conductor and generating heat by energization.

[0016] [2] The toothbrush according to the [1], wherein the heat conductor provided at the head portion is provided in an unexposed manner inside the head portion.

[0017] [3] The toothbrush according to the [1] or the [2], wherein the toothbrush comprises a substrate on which the heat generator is mounted, the brush portion is provided at a bristle planting surface of the head portion, and the heat conductor, the heat generator, and the substrate are arranged in this order from a back surface side opposite to the bristle planting surface toward the bristle planting surface in a first direction orthogonal to the bristle planting surface in the head portion.

[0018] [4] The toothbrush according to the [3], wherein the brush portion has a bundle of bristles planted in a bristle planting hole formed in the bristle planting surface, and a distance from a surface of the heat conductor on a side close to the bristle planting surface to a bottom surface of the bristle planting hole is longer than a distance from a surface of the heat conductor on the back surface side to a surface of the head portion on the back surface side.

[0019] [5] The toothbrush according to the [3], wherein the heat generator is arranged in the head portion, an area of the heat generator is 3% or more and 20% or less of an area of the heat conductor when viewed in a front view from a side opposite to the bristle planting surface in the first direction, and an area of the heat conductor is 60% or more of an area of the head portion when viewed in the front view.

[0020] [6] The toothbrush according to the [4], wherein a plurality of the bristle planting holes are provided in the bristle planting surface, and at least a part of all the bristle planting holes overlaps with the heat conductor when viewed in a front view from a side opposite to the bristle planting surface.

[0021] [7] The toothbrush according to the [4] or [6], wherein a minimum distance from an outermost periphery of the head portion to the heat conductor is equal to or greater than a minimum distance from the outermost periphery of the head portion to the bristle planting hole when viewed in a front view from a side opposite to the bristle planting surface.

[0022] [8] The toothbrush according to any one of the [3] to [7], wherein the heat conductor contains any one of copper, silver, and aluminum,

[0023] The size of the heat conductor in the first direction is 0.1 mm or more and 1.0 mm or less.

[0024] [9] The toothbrush according to any one of the [1] to the [8], wherein the toothbrush has a temperature detection section that detects the temperature of the heat generating body, and a control section that controls the amount of power supplied to the heat generating body based on the temperature detected by the temperature detection section.

[0025] Effects of the Invention

[0026] In the present application, a toothbrush that does not excessively heat the heat generating body, uniformly warms the head as a whole, and effectively heats the gums can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a front view of a toothbrush.

[0028] Figure 2 is a front view of a head.

[0029] Figure 3 is an A-A sectional view of Figure 2

[0030] Figure 4 is a control block diagram related to temperature control.

[0031] Figure 5 is a graph showing the temperature distribution of the sample of Experimental Example 4.

[0032] Figure 6 is a graph showing the temperature distribution of the sample of Experimental Example 7.

[0033] Figure 7 is a graph showing a control method related to temperature control. DETAILED DESCRIPTION

[0034] Hereinafter, referring to Figures 1 to 7 An embodiment of the toothbrush of the present application will be described.

[0035] In addition, the following embodiment represents one aspect of the present application and does not limit the present application, and can be arbitrarily changed within the scope of the technical idea of the present application. Furthermore, in the following drawings, the scale, the number, and the like of each structure are different from the actual configuration in order to easily understand each structure.

[0036] Figure 1 is a front view of a toothbrush 1.

[0037] ​The toothbrush 1 includes a grip portion 2 for a user to hold and a brush body 3 that is attached to the grip portion 2 in a detachable manner. The toothbrush 1 of the present embodiment is capable of heating and warming at least a portion of the brush body 3.

[0038] As an example, the grip portion 2 is cylindrical, and a power switch 4 is provided on a portion of the outer circumferential surface thereof. The grip portion 2 houses a battery 5 as a power source in the inside thereof in a detachable manner, and is capable of being replaced. Further, a connector portion not shown is provided at the attachment portion of the grip portion 2 and the brush body 3, and is used to connect an unshown power supply line in the grip portion 2 and a substrate 30 described later in the inside of the brush body 3.

[0039] The brush body 3 has a joint base portion 6, a neck portion 7, a head portion 10, the substrate 30, a heat generating body 40, and a heat conducting body 50. As the material of the joint base portion 6, the neck portion 7, and the head portion 10, resins such as polypropylene resin (PP), polyacetal resin (POM), polystyrene resin (PS), polyethylene terephthalate resin (PET), polybutylene terephthalate resin (PBT), acrylonitrile butadiene styrene resin (ABS), polyarylate resin, polycarbonate resin, acrylonitrile styrene resin (AS), and the like can be cited.

[0040] The joint base portion 6 is formed in a conical shape, and is attached to one end side in the length direction of the grip portion 2 in a detachable manner. The head portion 10 is formed in a substantially oblong shape when viewed in the front view from the side opposite to the bristle planting surface 12 described later. The head portion 10 is disposed on the other end side in the length direction of the grip portion 2. The neck portion 7 is disposed between the joint base portion 6 and the head portion 10. The neck portion 7 gradually widens in width from the head portion 10 toward the joint base portion 6 when viewed in the front view. The boundary in the length direction of the neck portion 7 and the head portion 10 is the position at which the head portion 10 gradually narrows in width and then starts to widen when viewed in the front view.

[0041] Figure 2 is a front view of the head portion 10. Figure 3 is Figure 2 is an A-A sectional view of

[0042] As shown in Figure 3 , the head portion 10 has a brush portion 11. The brush portion 11 is provided on the bristle planting surface 12 of the head portion 10.

[0043] In the following description, the length direction of the grip portion 2 will be simply referred to as the length direction, the direction orthogonal to the bristle planting surface 12 will be referred to as the thickness direction, and the direction parallel to the bristle planting surface 12 and orthogonal to the length direction of the grip portion 2 will be referred to as the width direction. The thickness direction corresponds to the first direction. Further, the bristle planting surface 12 side in the thickness direction will be appropriately described as the front side, and the side opposite to the bristle planting surface 12 will be appropriately described as the back side. Further, the side on which the brush body 3 is disposed in the length direction will be referred to as the front end side, and the side on which the grip portion 2 is disposed will be referred to as the back end side.

[0044] The brush portion 11 has a plurality of tufts 13. The tufts 13 are planted in planting holes 14 formed in the planting surface 12. The planting surface 12 has a plurality of planting holes 14. The planting hole 14 is a recessed portion recessed toward the back surface side from the planting surface 12. The tufts 13 are planted in the planting surface 12 by sandwiching a flat wire in a folded portion and driving the flat wire into the planting hole 14. The thickness of the head portion 10 is not particularly limited, and is preferably, for example, 5 mm or less from the viewpoint of insertability into the oral cavity.

[0045] The substrate 30 is embedded in the inside of the brush body 3 in a non-exposed state. As shown in FIG. 1, the substrate 30 is located in the center in the width direction and extends in the length direction. As shown in FIG. 2, the substrate 30 is disposed at a position closer to the back surface side than the planting hole 14. Figure 2 Figure 3 The substrate 30 is embedded in the inside of the brush body 3 in a non-exposed state. As shown in FIG. 1, the substrate 30 is located in the center in the width direction and extends in the length direction. As shown in FIG. 2, the substrate 30 is disposed at a position closer to the back surface side than the planting hole 14. Figure 4 Figure 4 As shown in FIG. 6, the substrate 30 has a power supply line, a temperature detecting portion 31, and a control portion 32, which are not shown. The control portion 32 can also be provided in the inside of the handle portion 2 instead of being provided in the substrate 30.

[0046] When the brush body 3 is attached to the handle portion 2, the power supply line is connected to a connector portion provided in the handle portion 2. The power supply line can be supplied with power from the battery 5 via the connector portion. The power supply from the handle portion 2 to the brush body 3 can also be wireless power supply. The temperature detecting portion 31 detects the temperature of the heat generating body 40. The temperature detecting portion 31 outputs the detected temperature of the heat generating body 40 to the control portion 32. The control portion 32 controls the amount of current supplied to the heat generating body 40 in accordance with the temperature of the heat generating body 40 detected by the temperature detecting portion 31 (see later for details).

[0047] The heat generating body 40 is embedded in the inside of the brush body 3 in a non-exposed state. The heat generating body 40 is provided in contact with the heat conducting body 50. In the present embodiment, the heat generating body 40 is provided in the head portion 10. The heat generating body 40 generates heat by being supplied with current. The heat generating body 40 is an electronic component that generates heat by itself using resistance. The heat generating body 40 includes a resistance body that generates heat using current, a protective film that covers the resistance body, and an electrode portion (all not shown). As the heat generating body 40, a chip resistance that is rigid, a film heater can be used. Among them, the chip resistance is preferred because the degree of freedom of control of the resistance is high by changing the cross-sectional area and the length. Furthermore, the chip resistance composed of silver, silver / palladium, ruthenium oxide is preferred. The heat generating body 40 is mounted on the back surface side of the substrate 30. The heat generating body 40 mounted on the substrate 30 is connected to the power supply line and can be supplied with current via the power supply line.

[0048] ​​The heat conductor 50 is in a flat shape extending in a direction orthogonal to the thickness direction. The heat conductor 50 is provided at least in the head portion 10. The heat conductor 50 is embedded in the inside of the brush body 3 in a non-exposed state. In the present embodiment, the heat conductor 50 is provided in the head portion 10. The heat conductor 50 can also be provided in the entire portion from the head portion 10 to the neck portion 7. In the case where the heat conductor 50 is also provided in the neck portion 7, the structure can also be such that the heat generator 40 is provided in the neck portion 7. The heat conductor 50 is formed of a material having a higher thermal conductivity than the material forming the head portion 10. As an example, the heat conductor 50 is formed of a metal. As the metal constituting the heat conductor 50, from the viewpoint of thermal conductivity, it is preferable to contain any one of copper, silver, and aluminum.

[0049] In the case where the metal constituting the heat conductor 50 contains any one of copper, silver, and aluminum, in addition to the excellent thermal conductivity, the processability is also excellent, and thus it is possible to easily process into a shape and size matching the head portion 10. Further, by processing the heat conductor 50 to be thin, the softness is maintained, and thus the flexing when using the toothbrush is not hindered.

[0050] Further, the corrosion resistance of copper, silver, and aluminum is also excellent, and corrosion is not likely to occur even in the oral cavity containing a large amount of moisture. Among copper, silver, and aluminum, from the viewpoint of the thermal conductivity and cost, it is preferable to be copper.

[0051] The heat conductor 50 is provided in contact with the heat generator 40. The heat conductor 50 is warmed by conducting the heat generated from the heat generator 40. The head portion 10 is warmed by the heat generated from the heat generator 40 via the heat conductor 50. The heat conductor 50 is disposed at a position on the back surface side from the substrate 30 and the heat generator 40. That is, in the head portion 10, the heat conductor 50, the heat generator 40, and the substrate 30 are disposed in this order from the back surface side to the bristle surface 12 at a position on the back surface side from the bristle hole 14.

[0052] In the present embodiment, the heat conductor is shown in a non-exposed manner in the drawings, but it can also be in an exposed manner. The non-exposed manner is preferable for the following reasons.

[0053] When a heat conductor 50 is provided on the head 10, if heat loss is to be suppressed and the target area such as the gums is directly heated, those skilled in the art (in the prior art) would conceive of exposing the heat conductor 50. Here, to maintain a constant temperature of the head 10, the electrical current supplied to the heating element 40, which serves as the heat source, needs to be controlled according to the temperature of the head 10. Since the head 10 is agitated within the oral cavity during brushing, the external temperature of the head 10 varies discretely. Therefore, if the heat conductor 50 is exposed from the head 10 and immediately conducts heat to the outside of the head 10, the heating element 40 must respond to this temperature change, potentially causing both the heating element 40 and the heat conductor 50 to momentarily reach high temperatures. Furthermore, since the heat conductor 50 has a higher thermal conductivity than the resin forming the head 10, it readily conducts heat to the oral tissues, increasing the risk within the oral cavity. Moreover, because the heat conductor 50 momentarily reaches high temperatures, the risk of deformation and deterioration of the resin forming the head 10 increases.

[0054] Furthermore, since the specific heat of the resin forming the head 10 is greater than that of the heat conductor 50, it is not easy to heat up or cool down. For example, the specific heat of the resin forming the head 10 is 1.93 J / (kg·K) when it is polypropylene, and the specific heat of the heat conductor 50 is 0.385 J / (kg·K) when it is made of copper.

[0055] Therefore, as a more preferred method, by embedding the heat conductor 50 into the interior of the brush body 3 in a non-exposed state, the heat preservation effect can be improved, and the temperature change of the head 10 can be made more gradual. This not only reduces the risk of deformation and deterioration of the resin forming the head 10, but also simplifies temperature control.

[0056] Furthermore, compared to the flat back side of the head 10 with uniform resin distribution, the wall thickness of the front side where the hair implantation surface 12 is located varies depending on the presence or absence of the hair implantation holes 14, thus complicating the structure.

[0057] Therefore, by positioning the heating element 40 and the heat conductor 50 on the back side of the substrate 30, the substrate 30 functions as a heat insulation material, thereby reducing the risk of the resin on the front side of the head 10 deforming due to heat.

[0058] Furthermore, because the gums have less temperature sensation, they can be affected by factors such as... Figure 3 As shown, a heat conductor 50, a heating element 40, and a substrate 30 are arranged sequentially from the back side of the head 10 toward the hair-planting surface 12, thereby preferentially heating the back side of the head 10. This allows for a warm and realistic sensation by heating the cheek side that is in contact with the back side when the head 10 is inserted into the mouth.

[0059] In addition, in order to prevent the heat of the heat conductor 50 and the heat generator 40 from adversely affecting the bristle holes 14, the base plate 30 is preferably a rigid base plate having a thickness, rather than a thin flexible base plate or a thin film base plate.

[0060] Preferably, as shown in FIG. 1, the distance Ta between the side of the heat conductor 50 close to the bristle face 12 and the bottom face 14a of the bristle hole 14 is longer than the distance Tb between the back side of the heat conductor 50 and the back side of the head 10. Figure 3

[0061] In order to reduce the heat loss from the heat conductor 50 to the oral cavity, it is preferable that the heat conductor 50 be close to the bristle face 12, but in the case where the heat conductor 50 is made close to the bristle face 12, as described above, the resin on the front side deforms due to heat or the wall thickness between the bottom face 14a of the bristle hole 14 and the heat conductor 50 becomes thin according to the change in the wall thickness corresponding to the presence or absence of the bristle hole 14, thereby increasing the risk of cracking of the head 10.

[0062] Therefore, by making the distance Ta longer than the distance Tb, it is possible to reduce the above-mentioned risk and reduce the heat loss from the heat conductor 50 to the oral cavity.

[0063] As the distance Tb, it is preferable that it be 1 mm or less.

[0064] In the case where the heat generator 40 is disposed in the head 10, the area of the heat generator 40 relative to the area of the heat conductor 50 is preferably 3% or more and 20% or less in the front view, and the lower limit value of the area of the heat conductor 50 relative to the area of the head 10 is preferably 60% or more and the upper limit value is preferably 100% or less in the front view.

[0065] Since the heat generator 40 is in the head 10, it is possible to warm the head 10 to the target temperature in a short time with the aid of the heat conductor 50.

[0066] In addition, the amount of heat generated by conduction is proportional to the cross-sectional area perpendicular to the direction of heat conduction. When the heat generator 40 is disposed in the neck 7, the width of the neck 7 is narrower than that of the head 10, and therefore it is difficult for heat to be conducted from the neck 7 to the head 10. In addition, during the period in which heat is conducted from the neck 7 to the head 10, heat is radiated from the surface of the heat conductor 50, and therefore the temperature difference between the head 10 and the neck 7 becomes large.

[0067] Therefore, before the head 10 reaches the target temperature, the neck 7 becomes high temperature, and therefore the deformation or degradation of the neck 7, the safety to the oral cavity, and the electric power become problems.

[0068] According to the above, the heat generator 40 is preferably disposed in the head 10.

[0069] ​If the power supplied to the heat generating body 40 is set as P (W), the specific heat as c (kJ), the density as p (kg / m 3 ), the volume as V (m 3 ), the temperature difference caused by heating as AT (°C), the heating time as t (h), and the Joule coefficient as a, the following relationship is obtained.

[0070] t = a x c x p x AT x V / P

[0071] From the above equation, it is clear that the heating time t is in proportion to the volume V, and when the heat generating body 40 is large and the volume V is large, the heating time t is long.

[0072] [Relationship between the size of the heat generating body 40 and the heating time t]

[0073] For the samples of Experimental Examples 1 to 3 in which the thin film heater and the chip resistor of the specifications shown in [Table 1] were used as the heat generating body 40, respectively, experiments were performed to confirm the time until the heat generating body 40 was heated to 40°C. As for the thin film heater, samples in which the resistance value was 5 Ω and 10 Ω were prepared, and as for the chip resistor, a sample in which the resistance value was 15 Ω was prepared. The current was supplied to the heat generating body 40 at a voltage of 3.0 V, and the time until heating to 40°C was measured.

[0074] [Table 1]

[0075] Experimental Example 1 Experimental Example 2 Experimental Example 3 Heating element 5 Ω thin film heater 10 Ω thin film heater 15 Ω chip resistor Area (mm2) 1870.1 1747.5 24.0 Initial temperature (°C) 24.5 24.7 24.8 Heating time (sec) 13 71 3

[0076] As shown in [Table 1], comparing the sample of Experimental Example 1 and the sample of Experimental Example 2, which have a small difference in the area of the heat generating body 40, it was confirmed that if the difference in the resistance value is 5 Ω, the time until the heat generating body 40 is heated to 40°C differs by less than 1 minute.

[0077] On the other hand, comparing the sample of Experimental Example 2, which has a large area of the heat generating body 40, and the sample of Experimental Example 3, which has a small area of the heat generating body 40, in the sample of Experimental Example 3, even if the resistance value is 5 Ω higher, the time until heating to 40°C is shortened by more than 1 minute.

[0078] From the above results, it was confirmed that by reducing the area of the heat generating body 40, the time to reach the target temperature can be greatly shortened.

[0079] [Relationship between the presence or absence of the heat conductor 50, the distance Tb, and the heating time and the cooling time]

[0080] As for the presence or absence of the heat conductor 50 and the distance Tb of the head 10, experiments were performed to confirm the time until the head 10 was heated to 40°C and the time until the head 10 heated to 40°C was cooled to 35°C using the samples of Experimental Examples 4 to 7 of the specifications shown in [Table 2].

[0081] In the case of the sample of Experimental Example 4, the head 10 formed of the polypropylene resin had the heat conductor 50 with a distance Tb of 0.5 mm.

[0082] The sample of Experimental Example 5 was a sample in which the distance Tb was 1.3 mm by providing a plate material formed of a polypropylene resin having a thickness of 0.8 mm on the back surface side of the head 10 relative to the sample of Experimental Example 4.

[0083] The sample of Experimental Example 6 was a sample in which the distance Tb was 2.1 mm by providing a plate material formed of a polypropylene resin having a thickness of 0.8 mm on the back surface side of the head 10 relative to the sample of Experimental Example 5.

[0084] The sample of Experimental Example 7 was a sample not having the heat conductor 50 relative to the sample of Experimental Example 4.

[0085] In the samples of Experimental Examples 4 to 7, the following structures were common.

[0086] The ratio of the area of the heat generating body 40 when viewed from the front surface to the area of the heat conductor 50 was 11%.

[0087] The ratio of the area of the heat conductor 50 when viewed from the front surface to the area of the head 10 was 82%.

[0088] [Experimental Method]

[0089] A voltage of 3.0 V and a current of 0.20 A were supplied to the heat generating body 40, and the time for the central portion of the head 10 of the sample of each experimental example to reach 40°C and the time for the temperature to decrease from 40°C to 35°C were measured.

[0090] [Table 2]

[0091]

[0092] As shown in [Table 2], it was confirmed that the greater the thickness of the resin on the back surface side relative to the sample of Experimental Example 4, the longer the time required for temperature increase and temperature decrease. In addition, it was confirmed that the temperature increase time was lengthened by 30 seconds or more and the temperature decrease time was lengthened by 5 seconds or more by increasing the thickness of the resin by 0.8 mm.

[0093] From the above results, it was confirmed that even a difference of 1 mm or less in the thickness of the resin on the back surface side of the heat conductor 50 has a large effect on the temperature increase time and the temperature decrease time, and has an effect on the usability of the toothbrush 1.

[0094] [Relationship between the heating time of the outermost portion of the head based on the presence or absence of the heat conductor 50]

[0095] The relationship between the heating time and the cooling time of the outermost portion of the head portion was confirmed using the samples of Experimental Example 4 and Experimental Example 7 described above.

[0096] [Experimental Methods]

[0097] The temperature and the time of the heat generator 40 when the outermost portion of the head portion 10 of each sample reached 40°C were measured while supplying a voltage of 3.0 V and a current of 0.20 A to the heat generator 40. A thermal imager was used to measure the temperature.

[0098] The heat conductor 50 was made of a copper plate.

[0099] The temperature of each sample was measured from the hair implantation surface 12 side.

[0100] [Table 3]

[0101]

[0102] It was confirmed that the temperature of the heat generator 40 differed by about 20°C between the case where the heat conductor 50 was present and the case where the heat conductor 50 was not present when the outermost portion of the head portion 10 was heated to 40°C.

[0103] Also, with respect to the time until the outermost portion of the head portion 10 was warmed, the sample of Experimental Example 4 having the heat conductor 50 was warmed to 40°C in a short time of 50 seconds or more under the above conditions.

[0104] Figure 5 is a graph showing the temperature distribution of the sample of Experimental Example 4. Figure 6 is a graph showing the temperature distribution of the sample of Experimental Example 7.

[0105] As shown in Figure 5 , in the sample of Experimental Example 4 having the heat conductor 50, it was confirmed that the surface of the head portion 10 was uniformly warmed to the vicinity of the outermost portion. In contrast, as shown in Figure 6 , in the sample of Experimental Example 7 not having the heat conductor 50, it was confirmed that the temperature of the periphery of the heat generator 40 was high, the temperature was low in the vicinity of the outermost portion, and a temperature gradient was generated in the head portion 10.

[0106] According to the results described above, it was confirmed that by adopting a structure having the heat conductor 50, it was possible to suppress the heat generator 40 from becoming high temperature and to uniformly and rapidly warm the head portion 10.

[0107] In the case where the amount of power supplied to the heat generator 40 has an upper limit value and the electric power P is constant at the upper limit value, in the case where the area of the heat conductor 50 of the head portion 10 is set to 100%, in the case where the area of the heat generator 40 with respect to the heat conductor 50 is greater than 20%, the time until warming is long because the heat generator 40 is too large.

[0108] Further, since the power supply to the heat generating body 40 is performed from the substrate 30 disposed so as to pass through the neck portion 7, the substrate 30 that fixes the heat generating body 40 also becomes large due to the increase in the heat generating body 40, and the production cost increases.

[0109] In a case where the area of the heat generating body 40 with respect to the heat conducting body 50 is less than 3%, the time difference in the conduction of heat between the central portion of the head portion 10 and the end edge of the head portion 10 becomes large when viewed in the front view, and the temperature difference becomes large.

[0110] By setting the area of the heat generating body 40 with respect to the heat conducting body 50 to be 3% or more and 20% or less, it is possible to warm the heat generating body 40 in a short time, and the heat conducting body 50 functions effectively in the head portion 10, the temperature difference between the central portion of the head portion 10 and the end edge of the head portion 10 becomes small, and it is possible to warm uniformly.

[0111] Further, the wall thickness of the front side where the hair implant surface 12 is present in the head portion 10 varies depending on the presence or absence of the hair implant hole 14, and thus the local warming is not ideal in terms of the shape change such as the diameter expansion of the hair implant hole 14 and the hair loss.

[0112] By the plurality of hair implant holes 14 at least partially overlapping the heat conducting body 50 when viewed in the front view, it is possible to warm all of the hair implant holes 14 without bias, and it is possible to prevent the shape change and suppress the risk of the hair loss due to the shape change.

[0113] The size in the thickness direction of the heat conducting body 50 is preferably 0.1 mm or more and 1.0 mm or less, and more preferably 0.1 mm or more and 0.5 mm or less.

[0114] Since the heat conducting body 50 needs to be disposed in a limited space in the toothbrush 1, it is assumed to be a relatively thin heat conducting body.

[0115] In a case where the size in the thickness direction of the heat conducting body 50 is less than 0.1 mm, the heat conducting body 50 is too thin in thickness, the cross-sectional area of the heat generating body 40 as a heat source that is perpendicular to the heat conducting direction becomes small, and the heat is difficult to conduct to the tip end. Thus, the heat is concentrated in the central portion, and the risk of the deformation and the crack due to the thermal expansion becomes large.

[0116] In a case where the size in the thickness direction of the heat conducting body 50 is more than 1.0 mm, the time difference in the conduction of heat between the central portion of the head portion 10 and the tip end portion of the head portion 10 becomes large, and the temperature difference becomes large.

[0117] It is preferable that the minimum distance Tc from the outermost periphery of the head portion 10 to the heat conducting body 50 when viewed in the front view be the same as or more than the minimum distance Td from the outermost periphery of the head portion 10 to the hair implant hole 14.

[0118] To suppress heat loss from the heat generator 40 to the inside of the oral cavity, it is preferable that the minimum distance Tc from the outermost periphery of the head 10 to the heat conductor 50 be short. However, in the case where the minimum distance Tc is smaller than the minimum distance Td, the heat retaining effect of the resin forming the head 10 is impaired, and there is a possibility that the temperature of the head 10 becomes unstable.

[0119] It is preferable that the minimum distance Tc from the outermost periphery of the head 10 to the heat conductor 50 be at least 0.8 mm or more and 2.0 mm or less.

[0120] In the toothbrush 1 described above, when the temperature of the head 10 is controlled, the control section 32 controls the power supply amount to the heat generator 40 based on the temperature of the heat generator 40 detected by the temperature detection section 31.

[0121] Figure 7 is a view showing a relationship of a set temperature and a voltage with respect to time, which indicates a control method related to temperature control.

[0122] The control section 32 supplies a voltage selected from among three voltages, a first voltage, a second voltage, and a third voltage, to the heat generator 40. The first voltage is the highest voltage. The second voltage is a voltage lower than the first voltage. The third voltage is a voltage lower than the first voltage and the second voltage.

[0123] As shown in Figure 7 , since the temperature needs to be rapidly increased at the time of start-up, the control section 32 supplies the high-voltage first voltage to the heat generator 40 to warm up the head 10. When the temperature of the heat generator 40 is greater than a reference value, the control section 32 supplies the low-voltage third voltage to the heat generator 40 to slow down the warming up of the head 10. When the temperature of the heat generator 40 is less than the reference value, the control section 32 supplies the medium-voltage second voltage to the heat generator 40 to enhance the warming up of the head 10. Thereafter, the control section 32 repeatedly performs temperature decrease by power supply of the third voltage and temperature increase by power supply of the second voltage in accordance with the detected temperature of the heat generator 40.

[0124] For example, in the case where on / off control is performed using only the high-voltage first voltage, the temperature sharply increases at the time of turning on and slowly decreases at the time of turning off. In the case of a high voltage, it is difficult to perform control in units of several degrees, and thus the time during which the temperature of the head 10 is the target temperature becomes short. In the case where on / off control is performed using only a medium voltage or a low voltage, it is possible to control in units of several degrees, but it takes time from the time of start-up to the time when the target temperature is reached, and the usability deteriorates.

[0125] The temperature of the head 10 is controlled by using a plurality of voltages, and thus the heat generator 40 is supplied with power at a high voltage at the time of start-up, whereby it is possible to rapidly warm up the head 10 to the target temperature, and thereafter the target temperature is kept constant.

[0126] As explained above, in the toothbrush 1 of the present embodiment, there are the thermally conductive body 50 provided to the head 10, which has a larger thermal conductivity than the head 10, and the heat generating body 40 provided in contact with the thermally conductive body 50 and generating heat by energization, and thus even in a case where the amount of electric power that can be output is limited due to a limitation on the power source that can be mounted, the thermally conductive body 50 conducts the heat generated by the heat generating body 40 to a larger range by thermal conduction, whereby the heat generating body 40 does not excessively generate heat, and the head 10 as a whole can be uniformly warmed, and the gingiva can be efficiently heated.

[0127] In the past, it has been preferable to immediately warm the head 10 as a whole at the start of the operation, and thus a plurality of or a large heat generating body has been considered to be mounted, but in this case, the heat generating body itself takes time to warm, and instead, it takes time until the head 10 is warmed, and the usability deteriorates, but in the toothbrush 1 of the present embodiment, by having the above-described structure, such a problem can be solved.

[0128] Further, in a case where the heat generating body 40 is downsized, the resin of the head 10 has a poor thermal conductivity, and thus heat is difficult to spread to the head 10 as a whole, and the heating portion becomes local. If the heating portion becomes local, the area in the head 10 that reaches the target temperature becomes small, and the efficiency in terms of warming the desired portion deteriorates. Further, in a case where the head 10 in which the wall thickness is changed due to the presence of the bristle holes 14 is warmed, it is considered that the resin of the portion in the head 10 in which the wall thickness is thin becomes soft at a high temperature, and thus is easily deformed by local heating, leading to the bristles being removed.

[0129] Further, in a case where the heat generating body 40 is downsized, in order to warm the head 10 as a whole, the heat generating body 40 must excessively generate heat, but it is difficult to uniformly warm, and the temperature gradient becomes large within the head 10, and the risk of deformation becomes large. Further, since the heat generating body 40 excessively generates heat, it becomes a problem in terms of safety, electric power, and deterioration.

[0130] Thus, in the toothbrush 1 of the present embodiment, the thermally conductive body 50 conducts the heat generated by the heat generating body 40 to a larger range by thermal conduction, whereby the above-described problems can be solved.

[0131] The above, a preferred embodiment of the present application is described with reference to the accompanying drawings, but the present application is of course not limited to this example. The shape, combination, etc. of each of the constituent members shown in the above-described example is one example, and various changes can be made based on design requirements, etc. without departing from the gist of the present application.

[0132] For example, in the above-described embodiment, a structure in which the thermally conductive body 50 and the heat generating body 40 are disposed to the head 10 is exemplified, but is not limited to this structure. As described above, the thermally conductive body 50 can also be a structure disposed to the entirety from the head 10 to the neck 7.

[0133] In this case, it is also possible that the heat generating body 40 is arranged in the neck portion 7.

[0134] In the case where the heat generating body 40 is arranged in the neck portion 7, the power supply line connected to the heat generating body 40 is shortened, and the power loss of the power supply can be reduced, so that the long life of the battery 5 can be sought.

[0135] Industrial applicability

[0136] The present application can be applied to a toothbrush.

[0137] Explanation of reference numerals

[0138] 1: toothbrush; 2: grip portion; 10: head portion; 11: brush portion; 12: hair mounting surface; 13: bundle of hairs; 14: hair mounting hole; 30: base plate; 31: temperature detecting portion; 32: control portion; 40: heat generating body; 50: heat conducting body.

Claims

1. A toothbrush characterized by comprising: a head portion having a brush portion; a grip portion provided on a rear end side of the head portion; a heat conductive body provided at least in the head portion, the heat conductive body having a larger thermal conductivity than the head portion; and a heat generating body provided in contact with the heat conductive body, the heat generating body generating heat by being energized.

2. The toothbrush according to claim 1, wherein the heat conductive body provided in the head portion is provided in an inner portion of the head portion in a non-exposed manner.

3. The toothbrush according to claim 1 or 2, wherein the toothbrush has a substrate on which the heat generating body is mounted, the brush portion is provided on a bristle planting surface of the head portion, in the head portion, the heat conductive body, the heat generating body, and the substrate are arranged in this order from a back surface side opposite to the bristle planting surface in a first direction orthogonal to the bristle planting surface.

4. The toothbrush according to claim 3, wherein the brush portion has a tuft of bristles planted in a bristle planting hole formed in the bristle planting surface, a distance from a surface of the heat conductive body on a side close to the bristle planting surface to a bottom surface of the bristle planting hole is longer than a distance from a surface of the heat conductive body on a back surface side to a surface of the head portion on the back surface side.

5. The toothbrush according to claim 3, wherein the heat generating body is arranged in the head portion, an area of the heat generating body is 3% or more and 20% or less of an area of the heat conductive body when viewed in a front view from a side opposite to the bristle planting surface in the first direction, an area of the heat conductive body is 60% or more of an area of the head portion when viewed in the front view.

6. The toothbrush according to claim 4, wherein a plurality of the bristle planting holes are provided in the bristle planting surface, at least a part of all the bristle planting holes overlaps the heat conductive body when viewed in a front view from a side opposite to the bristle planting surface.

7. The toothbrush according to claim 4, wherein a minimum distance from an outermost periphery of the head portion to the heat conductive body is equal to or more than a minimum distance from the outermost periphery of the head portion to the bristle planting hole when viewed in a front view from a side opposite to the bristle planting surface.

8. The toothbrush according to claim 3, wherein the heat conductive body contains any one of copper, silver, and aluminum, a dimension of the heat conductive body in the first direction is 0.1 mm or more and 1.0 mm or less.

9. The toothbrush according to claim 1 or 2, wherein the toothbrush has: a temperature detecting portion that detects a temperature of the heat generating body; and a control portion that controls an amount of energization to the heat generating body based on the temperature detected by the temperature detecting portion. ​

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