TW202228553A - toothbrush - Google Patents

Abstract

The present invention makes it possible to improve the material recyclability of a toothbrush and provide multiple types of toothbrushes by adopting a configuration in which a handle part and a brush part can be connected and separated, and also provides a toothbrush that can suppress decreases in usability that occur when brushing teeth via a configuration in which a handle part and a brush part can be connected and separated. A toothbrush 10 comprises a handle part 100, a brush part 200, and a seal mechanism 300. The handle part 100 comprises: a handle body 110 configured so as to be graspable and in which a hollow internal space 113 is formed; and a handle-side neck section 120 disposed further toward a longitudinal tip-end side than the handle body, and in which is formed a hollow opening part 130 that communicates with the internal space. The brush part 200 comprises: a head section 210 in which bristle bundles 211 have been implanted; and a brush-side neck section 220 extending, from the head section, toward a base end in the longitudinal direction, and in which has been formed a connection part 230 that can connect with and separate from the opening part. The seal mechanism 300 maintains the airtightness of the internal space in a state in which the opening part and the connection part are connected. The brush-side neck section has a closed structure in which a space that causes the outside and the inside of the head section to communicate is not formed.

Description

toothbrush

The present invention relates to a toothbrush.

Toothbrush users have a wide variety of oral conditions and design preferences. However, if a toothbrush matching each user is to be provided, the productivity is greatly deteriorated and it becomes expensive. In addition, recently, as a countermeasure against the microplastic problem or global warming, companies are required to respond to the environment. In this context, since most of the toothbrushes contain resin materials, and are further composed of a combination of a plurality of resin materials, the material recyclability is very poor. Therefore, in recent years, it has been desired to establish a fundamental improvement measure for the material recyclability of toothbrushes.

For example, Patent Document 1 discloses a toothbrush including a handle part having an internal space filled with a chemical solution; and a brush part having tufts of hair planted thereon and configured to be connectable/detachable to the handle part. Inside the brush portion, a flow path that communicates with the internal space of the handle portion in a state where the handle portion and the brush portion are connected is formed. In addition, this flow path communicates with the outside of the brush part via the vegetative pores of the brush part.

The toothbrush of patent document 1 can deform|transform a handle part so that a handle part may be crushed by a user holding and pressing the handle part with a finger|toe etc. of a user. When the handle portion is deformed so as to be crushed, the liquid medicine filled in the inner space is moved to the brush portion.

Like the toothbrush of Patent Document 1, when the handle portion and the brush portion are configured to be connectable/detachable, the handle portion and the brush portion can be recovered separately, or each of the handle portion and the brush portion can be selected from a variety of types. used in combination. Therefore, it is also considered that the toothbrush of Patent Document 1 has high material recyclability and can provide a wide variety of toothbrushes. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2005-13375

[The problem to be solved by the invention] Among them, regarding the toothbrush of Patent Document 1, as described above, when a user grips the handle portion, the handle portion is deformed so as to be crushed, so there are problems such as low usability when brushing teeth. In view of such a subject, if the airtightness of the internal space of the handle can be maintained in the state where the handle and the brush are connected, the handle can be prevented from being easily deformed when the user grips the handle.

However, in the toothbrush of Patent Document 1, as described above, in order to allow the liquid medicine to be fed to the brush portion, a flow path communicating with the tufted pores is formed inside the brush portion. Therefore, in the toothbrush of patent document 1, in the state which connected the brush part and the handle part, the airtightness of the internal space of the handle part cannot be maintained. Therefore, in the case of brushing teeth using the toothbrush of Patent Document 1, it is difficult to avoid a decrease in usability due to easy deformation of the handle.

Moreover, like the toothbrush of Patent Document 1, when the handle portion and the brush portion are configured to be connectable/detachable, and the handle portion is configured to be hollow, it is considered that the thickness of the handle portion can be further reduced by reducing the thickness of the handle portion. Improve the material recyclability of toothbrushes.

However, in the toothbrush of Patent Document 1, when the handle portion is formed with a thin thickness, the handle portion is more easily deformed. Therefore, in the toothbrush of Patent Document 1, when the handle portion is formed to have a thin thickness, the reduction in usability at the time of tooth brushing becomes remarkable. Therefore, in the toothbrush of Patent Document 1, it is difficult to significantly improve the material recyclability of the toothbrush while suppressing a decrease in usability at the time of brushing.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a toothbrush capable of improving the material recyclability of the toothbrush and providing a wide variety of toothbrushes by configuring the handle portion and the brush portion to be connectable/detachable. It is possible to suppress a decrease in usability at the time of brushing, which is caused by configuring the handle portion and the brush portion to be connectable/detachable. [Means of Solving Problems]

The toothbrush of the present invention for achieving the above objects has a handle portion, a brush portion, and a sealing mechanism, and the handle portion includes: a handle main body formed with a hollow inner space and configured so as to be able to be held; and a handle side neck a part, which is arranged on the front end side in the longitudinal direction of the handle body and has a hollow mouth part that communicates with the internal space, and the brush part includes: a head part, on which a hair bundle is planted; and a brush-side neck portion extending from the head to the base end side in the longitudinal direction and forming a connecting portion capable of being connected/detachable to the mouth portion, and the sealing mechanism is connected to the mouth portion and the mouth portion. The airtightness of the inner space is maintained in a state where the connection portion is connected, and the brush-side neck portion has a locking structure that does not form a space that communicates the inside and the outside of the head. [Effect of invention]

In the invention which has the said structure, since the handle part and the head part are comprised so that connection and detachment are possible, the material recyclability can be improved, and various kinds of toothbrushes can be provided. In addition, in the state where the handle portion and the head portion are connected, the airtightness of the inner space of the handle body can be maintained, so that the strength of the handle body can be improved. Therefore, the handle body can be prevented from being accidentally deformed when the user is holding the handle body to brush teeth. Thereby, the fall of usability accompanying the deformation|transformation of the handle|steering-wheel main body at the time of brushing a tooth can be suppressed. Furthermore, since the toothbrush of this invention can improve the intensity|strength of a handle|steering-wheel main body, further thinning of a handle|steering-wheel main body can be aimed at. Thereby, the material recyclability can be further improved.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the dimension ratio of a figure is exaggerated for convenience of description, and differs from an actual ratio.

1-3 is a figure which shows the structure of each part of the toothbrush 10 which concerns on embodiment. FIGS. 4 and 5 are diagrams showing an example of an operation sequence when the handle portion 100 and the brush portion 200 are separated from each other.

The arrow X1 shown in each figure shows the front end side of the toothbrush 10, and X2 shows the base end side of the toothbrush 10. FIG. The front end side and the proximal end side of the handle part 100 and the brush part 200 are in the same direction as the toothbrush 10 . The central axis of the toothbrush 10 is indicated by a chain line c1 in the figure.

＜Toothbrush＞ As shown in FIG. 1 , the toothbrush 10 includes a handle portion 100 , a brush portion 200 , and a sealing mechanism 300 .

The toothbrush 10 can be used for the purpose of cleaning the oral cavity of a user (natural person). When the user uses the toothbrush 10 , as shown in FIG. 1 , the handle portion 100 can be connected to the brush portion 200 . In a state where the handle portion 100 and the brush portion 200 are connected, the sealing mechanism 300 is formed in the connection region of the handle portion 100 and the brush portion 200 .

＜Handle＞ As shown in FIGS. 1 and 2 , the handle portion 100 includes: a handle body 110 formed with a hollow inner space 113 and configured to be grippable; A hollow mouth portion 130 that communicates with the internal space 113 is formed on the front end side in the longitudinal direction.

As shown in FIG. 1 , the handle body 110 is formed in a hollow manner. Therefore, the toothbrush 10 can reduce the amount of resin used for manufacture, as compared with a handle body including a solid structure filled with resin.

The shank main body 110 has a cylindrical shape having substantially the same outer diameter and substantially the same cross-sectional area over the entire length in the longitudinal direction. The base end surface (bottom surface) of the handle body 110 may be formed with a recessed portion recessed toward the front end side of the handle body 110 .

The outer diameter D1 (see FIG. 1 ) of the shank main body 110 can be formed, for example, to be 8.4 mm or more and 50 mm or less. In addition, from the viewpoint of reducing the amount of resin in the handle body 110 while maintaining usability when the user is brushing teeth, the outer diameter D1 of the handle body 110 is preferably, for example, 10 mm or more and 40 mm or less, and more preferably 15 mm. mm or more and 30 mm or less.

The outer diameter of the handle of a general toothbrush is about 10 mm. Among them, in consideration of the usability of children, the elderly or the disabled, the outer diameter of the handle is preferably formed as large as possible. For such a reason, a device or the like which is connected to the handle portion (handle) of the toothbrush to increase the outer diameter of the handle portion is sold. For example, when the shank is manufactured by general injection molding and the diameter is increased, since the amount of resin used in the manufacture increases, an increase in weight, generation of sink marks, and long molding time occur. topics such as chemistry. On the other hand, when the handle body 110 having a hollow structure is manufactured by blow molding as described later, it is possible to reduce the amount of resin used for manufacture while securing the strength of the handle body 110 . Therefore, it is possible to reduce the weight of the handle body 110, shorten the molding time, and prevent the reduction of the design appearance associated with the generation of sink marks, and the handle can be made easier to use than the handle of the general toothbrush exemplified above. The main body 110 has a larger diameter. Moreover, the effect of reduction of the environmental load and cost reduction by reducing the amount of resin can also be acquired.

The length L1 (refer to FIG. 1 ) of the shank main body 110 along the longitudinal direction can be formed, for example, to be 50 mm or more and 150 mm or less. In addition, from the viewpoint of preventing the shank main body 110 from being formed too long and the resin amount of the shank main body 110 from increasing unnecessarily, the length L1 of the shank main body 110 along the longitudinal direction is preferably 70 mm or more and 140 mm, for example. below, more preferably 90 mm or more and 120 mm or less.

The starting point and the end point as the measurement reference of the length L1 of the shank main body 110 along the longitudinal direction are the front end and the base end of the shank main body 110 . The front end of the handle body 110 is located at the boundary between the handle body 110 and the shoulder 140 . This boundary is the position where the expansion converges and the curvature changes from the shoulder 140 side to the shank main body 110 side with respect to the curve or straight line that expands with respect to the outer diameter (width) in front view as shown in FIG. c1 parallel way) where the angle changes. In addition, the measurement reference|standard of the said L1 can also be similarly applied to each modification (for example, the modification shown in FIG. 9) mentioned later. In addition, when the shank main body 110 has an asymmetric shape in the circumferential direction (asymmetrical shape in the cross-sectional view shown in FIG. 2 etc.) in the vicinity of the front end of the shank main body 110 , the length along the longitudinal direction of the shank main body 110 The boundary on the front end side of the reference of L1 can be defined by the position where the measured length L1 becomes the longest.

The wall thickness t1 (refer to FIG. 1 ) of the shank main body 110 can be formed, for example, to be 0.25 mm or more and 2.5 mm or less. In addition, from the viewpoint of effectively reducing the amount of resin in the handle body 110 while preventing the strength of the handle body 110 from becoming too small, the wall thickness t1 of the handle body 110 is preferably, for example, 0.40 mm or more and 1.5 mm or less, more preferably 0.50 mm or more and 1.25 mm or less. In addition, the wall thickness t1 of the shank main body 110 mentioned above is the dimension of the thinnest part of the shank main body 110.

In the present embodiment, the handle portion 100 including the handle body 110 and the handle side neck portion 120 can be manufactured by, for example, integral molding by stretch blow molding. By adopting the stretch blow molding method in the manufacture of the handle portion 100 , compared with the case of using the general direct blow molding method, the dimensional accuracy can be improved, and the subsequent steps such as burr removal can be omitted. In addition, by adopting the stretch blow molding method, the strength of the product can be improved by the high stretching effect of the parison, so even when the handle portion 100 is manufactured with a thin wall thickness, the user can be prevented from holding it. When the handle portion 100 collapses or the like.

In addition, the manufacturing method of the handle part 100 is not limited to the stretch blow molding method, for example, it can also manufacture by the injection blow molding method. Even in the case of using the injection blow molding method, it is possible to improve the product strength of the handle portion 100 as in the case of using the stretch blow molding method.

In the case of manufacturing the handle portion 100 by a blow molding method (stretch blow molding method or injection blow molding method), a cold parison method (two-stage method) can be adopted from the viewpoint of improving production efficiency. . Among them, the shank 100 can also be manufactured by a hot parison method (one-stage method).

The resin material used in the manufacture of the handle portion 100 is not particularly limited as long as it is a material capable of applying a blow molding method. For example, polyethylene, polypropylene, polyethylene terephthalate, polyethylene terephthalate, polyethylene Resin material mainly composed of lactic acid, polyhydroxybutyrate and polystyrene. Moreover, it is more preferable that the resin material used for manufacture of the handle|steering-wheel part 100 is the resin material which has polyethylene terephthalate as a main component. In the case of using a resin material mainly composed of polyethylene terephthalate, the difference in specific gravity with the material constituting the head 210, which will be described later, becomes clear, so that the user or the like can easily perform the operation between the handle 100 and the material. Separation of the head 210. In addition, it is also possible to utilize an existing recycling system that is separated based on the specific gravity of the material.

The handle body 110 may be printed or colored. Among them, from the viewpoint of recyclability, the handle main body 110 is more preferably made of colorless.

In order to improve the designability of the handle body 110 , the inner space 113 may be filled with solids such as resin or paper, semi-solids such as gels, colored liquids, and the like. The solid or semi-solid to be filled into the inner space 113 is preferably one that can be easily separated from the handle body 110 . As an example, it is preferable to use spherical beads, a tape-shaped film, or the like.

In addition, the method of improving the designability of the handle body 110 is more preferably a method of arranging a shrink label on the outer surface of the handle body 110 . If the handle body 110 is decorated with a shrink label, it is easy to separate the handle body 110 from the shrink label, so that the material recyclability can be improved. The contact angle of the surface of the shrink label with respect to the outer surface of the handle body 110 is more preferably, for example, 60° or more. By setting the contact angle to be 60° or more, sliding of the toothbrush can be suppressed, and water can be prevented from entering the gap between the handle body 110 and the shrink label. In addition, from the viewpoint of inhibiting the growth of fungi, it is preferable that the shrink label is subjected to antibacterial processing.

As shown in FIGS. 1 and 2 , the handle-side neck portion 120 is integrally formed with the handle body 110 and extends from the front end side of the handle body 110 .

The mouth portion 130 has a hollow structure like the handle body 110 . Inside the mouth portion 130, a hollow portion 133 that communicates with the inner space 113 of the handle body 110 is formed.

The mouth portion 130 is arranged at the front end of the handle portion 100 . A front end opening portion 131 is formed at the front end of the mouth portion 130 .

The outer diameter D2 (see FIG. 2 ) of the mouth portion 130 is formed to be smaller than the outer diameter D1 (see FIG. 1 ) of the handle body 110 . In addition, when the 1st recessed part 135 is formed in the mouth part 130, the outer diameter D2 of the said mouth part 130 is the outer diameter of the part other than the site|part where the 1st recessed part 135 is formed.

The outer diameter D2 of the mouth portion 130 can be formed, for example, to be 7.0 mm or more and 14.0 mm or less. In addition, in consideration of the outer diameter D1 of the handle main body 110 and the amount of elongation at the time of molding by stretch blow molding, the outer diameter D2 of the mouth portion 130 is preferably, for example, 8.0 mm or more and 13.0 mm or less, and more preferably 9.0 mm. Above and below 12.0 mm.

In the toothbrush 10 which concerns on this embodiment, the outer diameter ratio (D1/D2) of the outer diameter (D1) of the handle main body 110 and the outer diameter (D2) of the mouth part 130 can be 1.2 or more and 10 or less. This is based on the following reasons.

In the toothbrush 10, the larger outer diameter ratio (D1/D2) is an index indicating that more resin remains on the mouth portion 130 side during blow molding and the resin is extended longer on the handle body 110 side. Therefore, as for the toothbrush 10, the larger the outer diameter ratio (D1/D2) is, the thinner the handle body 110 is, and the resin amount of the handle body 110 is reduced accordingly. On the other hand, when the outer diameter ratio ( D1 / D2 ) becomes too large, the shank main body 110 is greatly reduced in strength along with the thinning of the shank main body 110 . Among them, in the case of using the blow molding method, the strength of the handle body 110 can be improved by the orientation of the resin during stretching. Taking such aspects into consideration, the outer diameter ratio (D1/D2) is preferably 1.2 or more and 10 or less, and more preferably 1.6 or more and 6 or less.

Regarding the toothbrush 10, when the outer diameter ratio (D1/D2) is 1.2 or more and 10 or less, the outer diameter D1 of the handle body 110 is preferably 20 mm, for example, and the outer diameter D2 of the mouth 130 is preferably 8 mm, for example .

The length L2 (see FIG. 1 ) of the mouth portion 130 along the longitudinal direction can be formed, for example, from 5 mm to 20 mm. In addition, from the viewpoint of preventing damage or the like around the mouth portion 130 due to the influence of the moment acting on the mouth portion 130 during tooth brushing, the length L2 of the mouth portion 130 along the longitudinal direction is preferably, for example, 5 mm or more and 16 mm or less, more preferably 5 mm or more and 12 mm or less.

The start point and the end point as a measurement reference of the length L2 along the longitudinal direction of the mouth portion 130 are the front end and the base end of the mouth portion 130 . The base end of the mouth portion 130 is located at the boundary between the mouth portion 130 and the shoulder portion 140 . This boundary is the position where the diameter converges and the curvature changes from the shoulder portion 140 side to the mouth portion 130 side with respect to the curve or straight line where the outer diameter (width) is narrowed in front view as shown in FIG. c1 parallel way) where the angle changes. In addition, the measurement standard of the said L2 can also be similarly applied to each modification (for example, the modification shown in FIG. 9) mentioned later. In addition, when the vicinity of the proximal end of the mouth portion 130 has a shape that is asymmetric in the circumferential direction (a shape that is asymmetric in the cross-sectional view shown in FIG. 2 , etc.) The boundary on the base end side of the reference of the length L2 can be defined by the position where the measured length L2 becomes the shortest.

In the toothbrush 10 which concerns on this embodiment, the length ratio (L1/L2) of the length (L1) along the longitudinal direction of the handle main body 110 and the length (L2) along the longitudinal direction of the mouth part 130 can be set. It is 2.5 or more and 30 or less. This is based on the following reasons.

As shown in FIGS. 1 and 2 , when brushing is performed with the mouth portion 130 connected to the brush-side neck portion 220 , the handle portion 100 is supported by the brush-side neck portion 220 via the mouth portion 130 . Taking the load applied to the mouth portion 130 into consideration, the mouth portion 130 preferably has a predetermined length or more. In particular, when the handle body 110 is formed long, the moment acting on the mouth portion 130 during tooth brushing also becomes large, and therefore, the mouth portion 130 needs to be formed long as a countermeasure. On the other hand, if the mouth part 130 is formed too long, the handle part 100 will be formed long, and the total length of the toothbrush 10 will also be long. Thereby, the operability of the toothbrush 10 at the time of tooth brushing falls. Moreover, since the total length of the toothbrush 10 becomes long, the resin amount used for the toothbrush 10 also increases. For the reasons described above, the length ratio (L1/L2) is preferably 2.5 or more and 30 or less, and more preferably 7.5 or more and 25 or less.

Regarding the toothbrush 10, when the length ratio (L1/L2) is 2.5 or more and 30 or less, the length L1 along the longitudinal direction of the handle body 110 is preferably 120 mm, for example, and the length L1 along the longitudinal direction of the mouth 130 is preferably 120 mm. The length L2 is preferably 8 mm, for example.

The thickness t2 (refer to FIG. 2 ) of the mouth portion 130 can be formed, for example, to be 0.8 mm or more and 3 mm or less. In addition, the thickness t2 of the mouth portion 130 is preferably 0.9 mm or more, for example, from the viewpoint of preventing the mouth portion 130 from being easily deformed when brushing with the mouth portion 130 connected to the brush side neck portion 220. 2.5 mm or less, more preferably 1.0 mm or more and 2.0 mm or less. In addition, when the 1st recessed part 135 is formed in the mouth part 130, the wall thickness t2 of the mouth part 130 is the wall thickness of the part other than the site|part where the 1st recessed part 135 is formed.

As shown in FIG. 2 , on the outer peripheral surface of the mouth portion 130 , a first concave portion 135 recessed toward the radially inner side (in the same direction as the center axis c1 side) of the mouth portion 130 may be formed.

The first concave portion 135 has a semicircular cross-sectional shape. The first concave portion 135 is formed in the vicinity of the approximate center position in the longitudinal direction of the mouth portion 130 . The first concave portion 135 is formed along the entire circumference of the outer peripheral surface of the mouth portion 130 .

The height of the first concave portion 135 (equivalent to the wall thickness of the mouth portion 130 at the first concave portion 135 ) is preferably, for example, 0.3 mm or more and 2.0 mm or less. When the first concave portion 135 is formed with a height of such a range, as shown in FIG. The hooking of the first concave portion 135 and the second convex portion 235 can effectively prevent the accidental separation of the handle-side neck portion 120 and the brush-side neck portion 220 .

In addition, the position where the first recessed portion 135 is formed, the cross-sectional shape of the first recessed portion 135, the number of the first recessed portion 135 to be provided, and the like are not particularly limited, and can be appropriately changed. In addition, the mouth portion 130 may be provided with, for example, a first convex portion protruding radially outward of the mouth portion 130 . The shape, position, number of installations, and the like of the first convex portion are not particularly limited. In addition, only the first concave portion 135 may be formed in the mouth portion 130, only the first convex portion may be formed, or both the first concave portion 135 and the first convex portion may be formed.

As shown in FIG. 1 , the handle-side neck portion 120 has a shoulder portion 140 formed on the proximal end side in the longitudinal direction of the mouth portion 130 .

The outer diameter of the shoulder portion 140 gradually increases from the side of the mouth portion 130 toward the side of the handle body 110 . The shoulder portion 140 has a hollow structure in which the hollow portion 133 of the mouth portion 130 located on the front end side of the shoulder portion 140 communicates with the inner space 113 of the handle body 110 .

Furthermore, the shoulder portion 140 has a curved shape in which the outer diameter gradually increases from the mouth portion 130 side toward the handle body 110 side in the front view shown in FIG. form a straight line. In addition, the handle portion 100 may also be a structure without the shoulder portion 140 . In such a configuration, the handle portion 100 may be configured to be connectable to the brush-side neck portion 220 via the mouth portion 130 .

The total length along the longitudinal direction of the shank portion 100 (the length obtained by adding the shank main body 110 and the shank side neck portion 120 ) can be formed to be, for example, 55 mm or more and 180 mm or less.

＜Brush department＞ As shown in FIGS. 1 and 2 , the brush part 200 includes: a head part 210 on which a hair bundle 211 is implanted; and a brush side neck part 220 extending from the head part 210 to the proximal end side in the longitudinal direction and formed There is a connecting portion 230 that can be connected/disconnected from the mouth portion 130 .

The connection portion 230 is formed at the proximal end of the brush portion 200 (the proximal end of the brush-side neck portion 220 ).

As shown in FIG. 2 , the connection portion 230 has an insertion portion 231 into which the mouth portion 130 and the shoulder portion 140 can be inserted. In the present embodiment, the insertion portion 231 is constituted by a space divided by the inner peripheral sides of the inner cylindrical portion 240 and the outer cylindrical portion 250 included in the connection portion 230 .

The brush-side neck 220 has a locking structure that does not form a space that communicates the inside and the outside of the head 210 . Specifically, as shown in FIG. 2 , the connection portion 230 of the brush-side neck portion 220 has a front end surface 232 that blocks the hollow space between the inside of the brush-side neck portion 220 and the outside of the brush-side neck portion 220 . communication between the insertion parts 231 of the Therefore, in the inside of the brush side neck 220, the space, the passage, the hole, etc. which connect the inside of the head part 210 and the outside of the head part 210 are not formed.

As shown in FIGS. 2 and 3 , the connecting portion 230 has an inner cylindrical portion 240 and an outer cylindrical portion 250 arranged to cover the inner cylindrical portion 240 with a gap g between the inner cylindrical portion 240 and the inner cylindrical portion 240 .

The connection part 230 formed in the base end of the brush side neck part 220 is given the shape which shows two cylindrical shapes. Of the two cylindrical shapes, the portion located on the inner peripheral side of the connecting portion 230 constitutes the inner cylindrical portion 240 , and the portion disposed on the outer peripheral side of the inner cylindrical portion 240 constitutes the outer cylindrical portion 250 .

Furthermore, the connection portion 230 may not be formed into a double-tube structure including the inner tube portion 240 and the outer tube portion 250 . For example, one space into which the mouth portion 130 and the shoulder portion 140 can be inserted may be constituted by a concave portion divided by the inner peripheral side.

As shown in FIG. 2 , the connecting portion 230 is formed with a second convex portion 235 , which is in contact with the outer periphery of the first concave portion 135 in a state where the mouth portion 130 and the shoulder portion 140 are inserted into the insertion portion 231 . face contact.

The second convex portion 235 is provided on the inner peripheral surface of the inner cylindrical portion 240 constituting the connecting portion 230 . The second convex portion 235 protrudes radially inward of the connection portion 230 (in the same direction as the center axis c1 side). The second convex portion 235 has a semicircular cross-sectional shape matching the shape of the first concave portion 135 .

The second convex portion 235 is formed at a position corresponding to the position where the first concave portion 135 is formed. In addition, the second convex portion 235 is formed along the entire circumference of the inner peripheral surface of the inner cylindrical portion 240 . Therefore, the second convex portion 235 abuts the outer peripheral surface of the first concave portion 135 over the entire circumference in a state where the mouth portion 130 and the shoulder portion 140 are inserted into the insertion portion 231 .

The height of the second convex portion 235 (corresponding to the wall thickness of the inner cylindrical portion 240 at the second convex portion 235 ) is preferably equal to or greater than 0.3 mm and less than or equal to 2.0 mm, for example, similarly to the first concave portion 135 .

In addition, the position where the second convex portion 235 is formed, the cross-sectional shape of the second convex portion 235 , the number of the second convex portion 235 to be provided, and the like can be appropriately changed in accordance with the first concave portion 135 . For example, when only the first concave portion 135 is formed in the mouth portion 130 , only the second convex portion 235 may be formed in the connecting portion 230 . In addition, when the first concave portion 135 and the first convex portion are formed in the mouth portion 130 , the second convex portion 235 and the second concave portion that can abut against the first convex portion may be formed in the connecting portion 230 .

From the viewpoint of inducing deflection of the inner cylindrical portion 240 with an appropriate deformation amount when the mouth portion 130 and the shoulder portion 140 are inserted into the insertion portion 231 , the wall thickness ta (see FIG. 2 ) of the inner cylindrical portion 240 may be, for example, 0.3 mm or more and 1.5 mm or less. The wall thickness ta of the inner cylindrical portion 240 is, for example, preferably 0.4 mm or more and 1.3 mm or less, and more preferably 0.6 mm or more and 1.1 mm or less. In addition, the thickness ta of the said example is the dimension of the thinnest part of the inner cylinder part 240, and it is the thickness of the base end vicinity of the inner cylinder part 240 in this embodiment.

In the state where the mouth portion 130 is inserted into the insertion portion 231, the mouth portion 130 and the inner cylindrical portion 240 can be protected from the outside and the sealing performance of the connecting portion 230 can be ensured. Fig. 2) For example, it can be formed to be 1 mm or more and 2 mm or less. The wall thickness tb of the outer cylindrical portion 250 is, for example, preferably 0.6 mm or more and 2.5 mm or less, and more preferably 0.8 mm or more and 1.8 mm or less. In addition, the wall thickness tb illustrated above is the dimension of the thinnest portion of the outer cylindrical portion 250 , and is the thickness near the proximal end of the outer cylindrical portion 250 in the present embodiment.

In the toothbrush 10 which concerns on this embodiment, it is preferable that the wall thickness ratio (ta/tb) of the wall thickness ta of the inner cylinder part 240 and the wall thickness tb of the outer cylinder part 250 is 0.15 or more and 1.5 or less. This is based on the following reasons.

When the mouth portion 130 and the shoulder portion 140 are inserted into the insertion portion 231 of the toothbrush 10 , the inner cylindrical portion 240 is deformed so as to be expanded, thereby improving the insertability of the mouth portion 130 and the shoulder portion 140 . Therefore, it is unfavorable to make the wall thickness ta of the inner cylindrical portion 240 too large. In addition, from the viewpoint of protecting the mouth portion 130 and the inner cylindrical portion 240 from the outside and ensuring the sealing performance of the connecting portion 230, the case where the outer cylindrical portion 250 can be easily deformed like the inner cylindrical portion 240 is not preferable. . For the reasons described above, it is not preferable that the wall thickness tb of the outer cylindrical portion 250 is formed to be too smaller than the wall thickness ta of the inner cylindrical portion 240, and the wall thickness ratio (ta/tb) is preferably 0.15 or more and 1.5 or less, more preferably It is 0.3 or more and 1.0 or less.

The gap g formed between the inner cylindrical portion 240 and the outer cylindrical portion 250 is formed from the viewpoint of facilitating the deformation of the outer cylindrical portion 250 at the time of the pressing operation to be described later, so that the connection portion 230 is easily separated from the mouth portion 130 and the shoulder portion 140 . The distance tc (refer to FIG. 3 ) is preferably formed to be, for example, 1 mm or more and 3 mm or less.

The material constituting the brush portion 200 is not particularly limited, and for example, polypropylene, polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polystyrene, nylon, and acrylonitrile can be used. Styrene resin, etc. The resin constituting the brush portion 200 is particularly preferably polypropylene or polyethylene. In addition, in the case of manufacturing the head 210 by integral molding, the hair constituting the hair bundle 211 is preferably not hair, but an elastomer with high hardness, especially polyamide, polyester, polystyrene, Any of polyurethane and silicone resin. Moreover, when manufacturing the hair bundle 211 and the head part 210 by integral molding, it is more preferable that the hair which comprises the hair bundle 211 is a thermoplastic polyurethane whose A hardness is 40 or more.

For example, the head 210 may have a structure in which the hair bundles 211 are planted by flat-line hair transplanting or anchor less (anchor free) hair transplanting, or the hair bundles 211 may be formed by A structure formed integrally with the head 210 . When the hair constituting the hair bundle 211 is not formed by integral molding with the head 210, for example, known ones such as nylon, polybutylene terephthalate, and polyethylene terephthalate can be used. to constitute.

In addition, the shape and size of the head 210, the material of the hair constituting the hair bundle 211, the number of plantings, the planting area, and the outer diameter are not particularly limited, and known structures can be appropriately employed.

The resin material constituting the brush side neck 220 is preferably a hard material. By selecting such a resin material, in the case of adopting a structure in which the handle portion 100 and the brush portion 200 are connected in a state where the connection portion 230 covers the mouth portion 130 as in the toothbrush 10 of the present embodiment, it can be covered with a hard resin. The outer peripheral surface of the mouth portion 130 . Accordingly, in the state where the handle portion 100 and the brush portion 200 are connected, the connection portion 230 can be prevented from being unexpectedly deformed, and the airtightness of the inner space 113 of the handle body 110 can be effectively prevented from being reduced. As a combination of resin materials that can exhibit the above-mentioned effects, for example, polyethylene, polypropylene, and polyethylene terephthalate can be used as the resin material constituting the handle portion 100, and the resin material constituting the brush side neck portion 220 can be used Polyacetal, polybutylene terephthalate, PCTA (including dicarboxylic acid components mainly composed of terephthalic acid and isophthalic acid, and 1,4 cyclohexane dimethanol glycol as the main components resin with glycol component), polyethylene terephthalate, acrylonitrile styrene, polypropylene, polyethylene.

＜Sealing Mechanism＞ As shown in FIG. 2 , the toothbrush 10 includes a sealing mechanism 300 that maintains the airtightness of the inner space 113 of the handle body 110 in a state where the mouth portion 130 and the connecting portion 230 are connected.

The sealing mechanism 300 includes a fitting portion 310 that maintains the handle body by fitting the handle-side neck portion 120 with the brush-side neck portion 220 along with the insertion of the mouth portion 130 and the shoulder portion 140 into the insertion portion 231 . Airtightness of the inner space 113 of 110 .

When the user uses the toothbrush 10, the handle portion 100 and the brush portion 200 can be connected by a simple operation of inserting the mouth portion 130 and the shoulder portion 140 into the insertion portion 231. In addition, the user can maintain the airtightness of the inner space 113 of the handle body 110 by connecting the handle portion 100 to the brush portion 200 using the sealing mechanism 300 formed in the connection area of the handle portion 100 and the brush portion 200 .

As the mouth 130 and the shoulder 140 of the handle-side neck 120 are inserted into the insertion portion 231 of the connecting portion 230 of the brush-side neck 220 , the fitting portion 310 partially makes the mouth 130 and the connecting portion 230 in close contact with each other. The toothbrush 10 seals the periphery of the mouth portion 130 and the shoulder portion 140 by the fitting by the fitting portion 310 . In the toothbrush 10 , the first concave portion 135 and the second convex portion 235 , the front end surface 132 of the mouth portion 130 and the front end surface 232 of the connecting portion 230 , the shoulder portion 140 and the base end surfaces 242 and 252 of the respective cylindrical portions 240 and 250 , respectively. The fitting part 310 is constituted by cooperation of the two.

Specifically, the sealing mechanism 300 (the fitting portion 310 ) can exert the airtightness that can maintain the airtightness of the internal space 113 of the handle body 110 in a state where the handle side neck portion 120 and the brush side neck portion 220 are mechanically connected. The structure is not limited. For example, the sealing mechanism 300 may be configured to maintain the airtightness of the inner space 113 of the handle body 110 by closely contacting the outer peripheral surface of the mouth portion 130 with the inner peripheral surface of the inner cylindrical portion 240 over the entire area in the longitudinal direction. sex. In addition, for example, the sealing mechanism 300 may be configured such that the screw portion formed on the outer peripheral surface of the mouth portion 130 and the screw portion formed on the inner peripheral surface of the inner cylindrical portion 240 constituting the connection portion 230 are screwed together, The airtightness of the inner space 113 of the handle body 110 is maintained.

As shown in FIG. 2 , the front end surface 132 of the mouth portion 130 is in contact with the front end surface 232 of the connecting portion 230 located on the front end side of the insertion portion 231 in a state where the mouth portion 130 and the shoulder portion 140 are inserted into the insertion portion 231 . . Therefore, in the state where the handle-side neck portion 120 and the brush-side neck portion 220 are connected, the front end surface 132 of the mouth portion 130 and the front end surface 232 of the connecting portion 230 are in close contact, so that the sealing performance of the sealing mechanism 300 can be improved.

2 , the proximal end surface 242 of the inner cylindrical portion 240 and the proximal end surface 252 of the outer cylindrical portion 250 abut against the shoulder portion 140 in a state where the mouth portion 130 and the shoulder portion 140 are inserted into the insertion portion 231 . Therefore, in the state where the handle-side neck portion 120 and the brush-side neck portion 220 are connected, the base end face 242 of the inner cylindrical portion 240 and the base end face 252 of the outer cylindrical portion 250 are in close contact with the shoulder portion 140, so that the sealing mechanism 300 can be further improved. of sealing.

Furthermore, when the brush-side neck portion 220 includes the inner cylindrical portion 240 and the outer cylindrical portion 250, the base end surface 242 of the inner cylindrical portion 240 and the base end surface 252 of the outer cylindrical portion 250 are configured to The end surface is in contact with the shoulder portion 140 , so that the sealing performance of the sealing mechanism 300 can be improved. Therefore, as shown in the present embodiment, the base end surfaces 242 and 252 of the inner cylindrical portion 240 and the outer cylindrical portion 250 may not be configured such that the respective base end surfaces 242 and 252 of the inner cylindrical portion 250 are in contact with the shoulder portion 140 . For example, only one of the base end surfaces may be configured such that the shoulder portion 140 Abut.

Next, referring to FIGS. 4 and 5 , an operation procedure when separating the brush-side neck portion 220 from the handle-side neck portion 120 will be described.

The fitting portion 310 is configured to be able to release the fitting of the connection portion 230 with the mouth portion 130 and the shoulder portion 140 in accordance with a pressing operation of the connection portion 230 that presses the brush side neck portion 220 from the outer peripheral surface side. Specifically, as shown in FIG. 4 , the user can bend the outer cylindrical portion 250 toward the gap g by sandwiching the outer peripheral surface of the outer cylindrical portion 250 constituting the connecting portion 230 with fingers or the like and applying a force F. When the outer cylindrical portion 250 is bent toward the gap g side, the inner peripheral surface of the outer cylindrical portion 250 comes into contact with the inner cylindrical portion 240 . The inner cylindrical portion 240 is pressed by the outer cylindrical portion 250 from the outer peripheral side of the inner cylindrical portion 240 , so that the engagement of the second convex portion 235 with respect to the first concave portion 135 is released.

As shown in FIG. 5 , the user can move the handle portion 100 and the brush portion 200 toward the front end side and the base end side in a state in which the engagement of the second convex portion 235 with respect to the first concave portion 135 is released. It moves in a way that simply releases the connection between the handle 100 and the brush 200 .

As described above, in the toothbrush 10 according to the present embodiment, since the handle 100 and the head 210 are configured to be connectable/detachable, it is possible to improve material recyclability and provide a wide variety of toothbrushes. In addition, in the state where the handle portion 100 and the head portion 210 are connected, the airtightness of the inner space 113 of the handle body 110 can be maintained, so that the strength of the handle body 110 can be improved. Therefore, the handle body 110 can be prevented from being accidentally deformed when the user holds the handle body 110 to brush teeth. Thereby, the reduction of usability accompanying the deformation of the handle main body 110 at the time of tooth brushing can be suppressed. Furthermore, since the toothbrush 10 can improve the intensity|strength of the handle main body 110, the further thinning of the handle main body 110 can be aimed at. Thereby, the material recyclability can be further improved.

Next, the modification of the toothbrush which concerns on this invention is demonstrated. In the description of each modification, overlapping descriptions related to members and contents already described in the above-described embodiment are omitted.

<Variation 1> A partial cross-sectional view of the toothbrush according to Modification 1 is shown in FIG. 6 .

In the modification 1, the fitting part 310 is comprised so that the fitting of the mouth part 130 and the shoulder part 140 and the insertion part 231 can be cancelled|released with the rotation operation which rotates the brush part 200 and the handle part 100 relatively.

As shown in FIG. 6, the inner cylinder part 240 and the outer cylinder part 250 which comprise the connection part 230 are comprised so that the length along a longitudinal direction may differ in the part of a part of the circumferential direction with reference to the central axis c1. In the example shown in FIG. 6, the inner cylinder part 240 and the outer cylinder part 250 are formed so that the lower part in the figure is longer than the upper part. In addition, the shoulder 140 is formed in a cross-sectional shape such that a part of the circumferential direction is an upright wall surface in accordance with the difference in length between the inner cylinder part 240 and the outer cylinder part 250 .

If the user rotates the inner cylinder part 240 and the outer cylinder part 250 as indicated by the arrow r in the figure, the length of the inner cylinder part 240 and the outer cylinder part 250 can be formed to be longer and the upright part of the shoulder part 140 can be formed. partial touch. Thereby, the user can release the fitting by the fitting part 310 , and can easily separate the handle part 100 and the brush part 200 .

<Variation 2> A partial cross-sectional view of the toothbrush according to Modification 2 is shown in FIGS. 7 and 8 .

In the toothbrushes according to Modification 2 and Modification 3, the mouth portion 130 has a predetermined thick portion 138 . The thick portion 138 is located on the proximal end side of the front end of the mouth portion 130 , and is formed to be thicker than the front end of the mouth portion 130 . The toothbrush having the thick portion 138 has the following advantages.

When the handle portion 100 is manufactured by blow molding, by forming the thick portion 138 in advance, the handle body 110 can be uniformly extended and expanded in the longitudinal direction during blow molding. As a result, it is possible to prevent the shank main body 110 from forming a portion where the strength is locally reduced.

The thick-walled portion 138 may be, for example, a neck ring type (an annular shape obtained by increasing the outer diameter of a part of the mouth portion 130 ) as shown in FIG. The base end side is formed in a shape in which the thickness portion is increased toward the shoulder portion 140 side). When the thick-walled portion 138 is formed of a neck ring type, the thick-walled portion 138 can be caught and transported at the time of transport in the manufacturing process of the toothbrush, so that productivity can be improved.

The thickness ratio (t3/t1) of the thickness t3 of the thick part 138 and the thickness t1 (see FIG. 1 ) of the mouth part 130 is preferably 1.2 to 3, for example, and more preferably 1.5 to 2.5.

<Variation 3> Variation 3 regarding the shape of the handle body 110 is shown in FIGS. 9 to 11 .

The cross-sectional shape of the handle main body 110 does not need to have a cylindrical shape that is substantially uniformly formed along the longitudinal direction as shown in FIG. 1 . For example, from the viewpoint of improving the strength, as shown in FIG. 9 , it may be formed in a barrel shape in which the cross-sectional area of the proximal end side is larger than the cross-sectional area of the distal end side. In addition, for example, the shape of the cross section orthogonal to the central axis c1 may be formed by a polygonal shape, or a shape having a necked shape in which the cross-sectional area periodically increases and decreases. In addition, as a method of holding a toothbrush, there are known methods of holding a stick by hand or a method of holding a pen. When holding the toothbrush by these methods, in order to allow the user to firmly hold the toothbrush, a thumb or forefinger may be provided. and concavities and convexities of the middle finger, etc.

In addition, by providing the rib (horizontal rib) extending in the circumferential direction shown in FIG. 10 and/or the rib (longitudinal rib) extending in the longitudinal direction shown in FIG. strength.

<Variation 4> 12-14, the modification 4 concerning the time for improving the sealing performance of the sealing mechanism 300 (fitting part 310) is shown.

For example, as shown in FIG. 12 , the toothbrush may have a sealing member 410 arranged between the front end surface 132 of the mouth portion 130 and the front end surface 232 of the connecting portion 230 . By arranging the sealing member 410 in the toothbrush, the adhesiveness between the front end surface 132 of the mouth portion 130 and the front end surface 232 of the connecting portion 230 can be improved. Thereby, the airtightness of the inner space 113 of the handle body 110 can be further improved. The sealing member 410 may be constituted by, for example, a known O-ring such as an elastomer, or a ring or sheet of polyethylene (PE) or polypropylene (PP) having low hardness.

For example, as shown in FIG. 13 , the toothbrush may have a flap structure 420 on the front end surface 232 of the connecting portion 230 for improving the airtightness between the front end surface 132 of the mouth portion 130 and the front end surface 232 of the connecting portion 230 . The valve structure 420 may be constituted by, for example, a cusp portion in which a part of the distal end surface 232 of the connection portion 230 protrudes toward the center axis c1 side. By providing the flap structure 420 in the toothbrush, the adhesion between the front end surface 132 of the mouth portion 130 and the front end surface 232 of the connecting portion 230 can be improved. Thereby, the airtightness of the inner space 113 of the handle body 110 can be further improved.

For example, as shown in FIG. 14, the toothbrush may have the adhesive material 430 arrange|positioned between the outer peripheral surface of the mouth part 130, and the inner peripheral surface of the inner cylinder part 240. The adhesive material 430 is preferably, for example, a water-insoluble and water-repellent grease or the like whose viscosity is appropriately adjusted. By providing the adhesive material 430 in the toothbrush, the adhesiveness between the outer peripheral surface of the mouth portion 130 and the inner peripheral surface of the inner cylindrical portion 240 can be improved. Thereby, the airtightness of the inner space 113 of the handle body 110 can be further improved.

In addition, the structure demonstrated in the said each modification can be selectively and arbitrarily combined in the toothbrush of this invention, unless the effect of each modification is impaired.

As mentioned above, although the toothbrush which concerns on this invention was demonstrated by embodiment and a modification, this invention is not limited only to the content demonstrated in the specification, It can change suitably based on description of a claim.

For example, in the toothbrush described in the embodiment, when connecting the handle portion to the brush portion, a portion of the handle-side neck portion is covered by the brush-side neck portion, but it is not limited to this structure. The toothbrush may also have a structure in which a portion of the brush-side neck portion is covered by the handle-side neck portion when the handle portion and the brush portion are connected. That is, it is also possible to have a structure in which a part of the brush-side neck portion is inserted into the handle-side neck portion.

10: Toothbrush 100: Handle 110: handle body 113: Interior Space 120: Shank side neck 130: Mouth 131: Front opening part 132: Front end face of mouth 133: hollow part 135: The first recess 138: thick wall 140: Shoulder 200: Brush Department 210: Head 211: Hair Bundle 220: Brush Side Neck 230: Connector 231: Insertion 232: Front end face of connecting part 235: Second convex part 240: Inner cylinder 242: Base end face of inner cylinder 250: Outer cylinder 252: Base end face of outer cylinder 300: Sealing mechanism 310: Fitting part 410: Sealing member 420: Flap Structure 430: Adhesive material D1: The outer diameter of the shank body D2: The outer diameter of the mouth c1: the central axis of the toothbrush g: gap t1: Wall thickness of shank body t2: Wall thickness of mouth t3: Thickness of thick wall ta: Wall thickness of inner cylinder tb: wall thickness of outer cylinder tc: the distance of the gap F: force L1: The length of the handle body along the longitudinal direction L2: The length of the mouth along the longitudinal direction r, X1, X2: arrow

1 : is a partial cross-sectional view which shows the toothbrush which concerns on embodiment of this invention. FIG. 2 is an enlarged view of a portion 2A surrounded by a chain line in FIG. 1 . FIG. 3 is a cross-sectional view taken along line 3A-3A of FIG. 2 . 4 is a partial cross-sectional view showing an example of an operation sequence when the handle portion and the brush portion are separated. 5 is a partial cross-sectional view showing an example of an operation sequence when the handle portion and the brush portion are separated. 6 is a partial cross-sectional view showing a part of the toothbrush according to Modification 1. FIG. 7 is a partial cross-sectional view showing a part of the toothbrush according to Modification 2. FIG. 8 is a partial cross-sectional view showing a part of the toothbrush according to Modification 2. FIG. 9 is a partial cross-sectional view showing a toothbrush according to Modification 3. FIG. 10 is a partial cross-sectional view showing a toothbrush according to Modification 3. FIG. 11 is a partial cross-sectional view showing a toothbrush according to Modification 3. FIG. 12 is a partial cross-sectional view showing a part of the toothbrush according to Modification 4. FIG. 13 is a partial cross-sectional view showing a part of the toothbrush according to Modification 4. FIG. 14 is a partial cross-sectional view showing a part of the toothbrush according to Modification 4. FIG.

10: Toothbrush

100: Handle

110: handle body

113: Interior Space

120: Shank side neck

130: Mouth

133: hollow part

140: Shoulder

200: Brush Department

210: Head

211: Hair Bundle

220: Brush Side Neck

230: Connector

240: Inner cylinder

250: Outer cylinder

300: Sealing mechanism

310: Fitting part

D1: The outer diameter of the shank body

c1: the central axis of the toothbrush

t1: Wall thickness of shank body

L1: The length of the handle body along the longitudinal direction

L2: The length of the mouth along the longitudinal direction

X1, X2: Arrow

Claims (9)

A toothbrush has a handle, a brush, and a sealing mechanism, The handle portion includes: a handle body formed with a hollow interior space and configured to be grippable; and a handle side neck portion disposed on the front end side in the longitudinal direction of the handle body and formed There is a hollow mouth communicating with the inner space, The brush portion includes: a head portion on which a hair bundle is implanted; and a brush-side neck portion extending from the head portion toward the base end side in the longitudinal direction and formed with a connection and separation of the mouth portion. connector, The sealing mechanism maintains the airtightness of the inner space in a state where the mouth portion and the connecting portion are connected, and The brush side neck has a locking structure, and the locking structure does not form a space where the inside and the outside of the head communicate with each other. The toothbrush according to claim 1, wherein an outer diameter of the mouth portion is formed to be smaller than an outer diameter of the handle body, The handle-side neck portion has a shoulder formed on the base end side in the longitudinal direction rather than the mouth portion, and the outer diameter gradually changes from the mouth portion side toward the handle body side Big, The connection portion has an insertion portion into which the mouth portion and the shoulder portion can be inserted, The sealing mechanism includes a fitting portion for fitting the brush-side neck portion and the handle-side neck portion by inserting the mouth portion and the shoulder portion into the insertion portion. The airtightness of the inner space is maintained. The toothbrush according to claim 2, wherein a front end surface of the mouth portion is in a state where the mouth portion and the shoulder portion are inserted into the insertion portion, and the front end surface of the mouth portion and the front end side of the insertion portion The front end surfaces of the connecting portions are in contact with each other. The toothbrush according to claim 2 or claim 3, wherein a first recessed portion recessed radially inward of the mouth portion and/or radially outward of the mouth portion is formed on the outer peripheral surface of the mouth portion protruding first protrusion, A second convex portion abutting on the outer peripheral surface of the first concave portion and/or with the first concave portion in a state where the mouth portion and the shoulder portion are inserted into the insertion portion are formed in the connecting portion. A second concave portion with which the outer peripheral surface of the convex portion abuts. The toothbrush according to any one of claims 2 to 4, wherein the outer diameter ratio (D1/D2) of the outer diameter (D1) of the handle body to the outer diameter (D2) of the mouth portion is 1.2 more than 10 and less than 10. The toothbrush according to any one of claim 2 to claim 5, wherein the length (L1) of the handle body along the longitudinal direction is equal to the length (L2) of the mouth portion along the longitudinal direction The length ratio (L1/L2) is 2.5 or more and 30 or less. The toothbrush according to any one of Claims 2 to 6, wherein the fitting portion is configured so as to be capable of engaging the brush portion with the The fitting is released by a rotational operation in which the handle portion relatively rotates. The toothbrush according to any one of Claims 2 to 7, wherein the connecting portion has an inner cylindrical portion, and is disposed so as to cover the inner cylindrical portion with a gap therebetween. the outer cylinder, The base end face of the inner cylindrical portion and/or the base end face of the outer cylindrical portion abuts on the shoulder portion in a state where the mouth portion and the shoulder portion are inserted into the insertion portion. The toothbrush according to any one of Claims 2 to 8, wherein the mouth portion has a thick-walled portion, the thick-walled portion is located on the base end side with respect to the front end of the mouth portion, It is formed so that the wall thickness is thicker than the front-end|tip of the said opening part.

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