CN111031850A

CN111031850A - Tooth brush

Info

Publication number: CN111031850A
Application number: CN201880051388.4A
Authority: CN
Inventors: 木本雄也
Original assignee: Lion Corp
Current assignee: Lion Corp
Priority date: 2017-08-09
Filing date: 2018-07-31
Publication date: 2020-04-17
Anticipated expiration: 2038-07-31
Also published as: KR20200037203A; JP2019030583A; CN111031850B; WO2019031314A1

Abstract

The invention aims to provide a toothbrush which has excellent operability even if a handle body is thin and can be used for various holding methods. The brush handle part (30) comprises: a plurality of side surface side pole parts which are arranged along the long axis direction under the main view perpendicular to the hair planting surface (11) and the width of the side surface direction is continuously changed in bilateral symmetry; a side surface side extremely small portion which is arranged between the side surface side extremely large portions and whose width in the side surface direction continuously changes bilaterally symmetrically; a plurality of front-side extremely large sections (51, 52) which are arranged along the longitudinal direction in a side view and whose thickness continuously changes; a front-side extremely small portion (53) which is arranged between the front-side extremely large portions and whose thickness continuously changes; and a first straight section (54) extending substantially linearly from the boundary (31) between the neck section (20) and the handle section on the back side to the rear end side. The neck portion has a second straight section (22) that extends linearly from the rear end of the head portion toward the boundary on the back side. The boundary has a back-side extremely large portion (55) having a continuously changing thickness at a position closer to the tip end side than a front-side extremely large portion located closest to the tip end side.

Description

Tooth brush

Technical Field

The present invention relates to toothbrushes.

The present invention is based on the priority claim of Japanese patent application No. 2017-154340 filed in Japan on 8/9/2017, the contents of which are incorporated herein by reference.

Background

A general toothbrush includes a handle body and a bristle-implanted portion, the handle body including: the brush comprises a brush head part implanted with tufts, a brush handle part held in use, and a brush neck part connecting the brush head part and the brush handle part, wherein the tuft implantation part is formed by implanting tufts of bristles on a tuft implantation surface of the brush head part.

In a toothbrush as an oral cavity cleaning tool, in order to improve a cleaning effect which is a most necessary function, it is effective to appropriately contact all cleaning target portions such as tooth surfaces, occlusal surfaces, interdental portions, and tooth necks of implant portions with each other, and narrow a brush neck portion to improve the operability in the oral cavity. However, if the operability of the toothbrush in the oral cavity is improved by merely narrowing the brush neck portion, the strength of the brush handle body is insufficient, the amount of deflection of the brush neck portion becomes excessively large, and the cleaning effect tends to be reduced.

Therefore, patent document 1 discloses the following toothbrush: by changing the cross-sectional profile of the brush neck portion in a specific shape from the brush head portion toward the brush holder portion and by restricting the bending direction of the brush neck portion in stages, a high cleaning effect can be obtained even if the brush neck portion is narrowed.

[ Prior art documents ]

[ patent document ]

Patent document 1: japanese patent laid-open publication No. 2013-118944

Disclosure of Invention

(problems to be solved by the invention)

However, the thin brush handle including the brush neck portion may not provide a sufficient feeling of adhesion and stability during gripping, and may deteriorate the operability. Therefore, the brush handle is easy to slide when being held, the brush head is difficult to be inserted into a desired position accurately, and it is difficult to appropriately control the pressure during brushing. In addition, when the brush holder is held, a holding method such as a pen-grip type or a palm grip type may be used, but the above-described toothbrush cannot sufficiently cope with such a holding method.

The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a toothbrush which is excellent in operability even when a handle body is thin and can be applied to various holding methods.

(means for solving the problems)

According to a first aspect of the present invention, there is provided a toothbrush comprising: a brush head portion which is arranged on the front end side in the long axis direction and is formed by implanting hair bundles on a hair implanting surface; a brush neck part extending from the rear end side of the brush head part; and a brush holder portion extending to a rear end side of the brush neck portion, the brush holder portion including: a plurality of side surface side pole sections which are arranged along the long axis direction in a front view when viewed from a front direction perpendicular to the flocked surface, and in which widths in side surface directions perpendicular to the long axis direction and the front direction are continuously changed in bilateral symmetry; a side surface side extremely small portion which is arranged between the side surface side extremely small portions and whose width in the side surface direction continuously changes bilaterally symmetrically; a plurality of front-side extremely large portions that are arranged along the longitudinal direction on the hair-planted surface side in the front direction as viewed from the side direction and that continuously change in thickness; a front-side extremely small portion which is arranged between the front-side extremely large portions and in which the thickness continuously changes; and a straight step portion that is disposed closer to the rear end side than a boundary between the brush neck portion and the brush shank portion on the rear surface side opposite to the bristle-implanted surface in the front direction, and that extends substantially linearly from the boundary toward the rear end side, wherein the boundary has a rear surface side pole large portion that is disposed closer to the front end side than the front surface side pole large portion located closest to the front end side, and that continuously changes in thickness.

In the toothbrush according to one aspect of the present invention, the outer peripheral surface of the handle portion includes a hard portion made of a hard resin and a soft portion made of a soft resin, and the front-side extremely large portion disposed closest to the distal end side includes the soft portion.

In the toothbrush according to one aspect of the present invention, the soft portion disposed in the front-side extremely large portion closest to the distal end side protrudes from the hard portion around the soft portion.

In the toothbrush according to one aspect of the present invention, the soft portion disposed in the front-side extremely large portion closest to the tip end side is disposed in plurality at intervals in the longitudinal direction.

In the toothbrush according to one aspect of the present invention, the head portion has a minimum thickness of 2mm to 4mm, and the neck portion has a minimum thickness in the front direction and a minimum width in the side direction of 3.0mm to 4.5mm, respectively.

(effect of the invention)

The present invention can provide a toothbrush which is excellent in operability even when the handle body is thin and can be used for various holding methods.

Drawings

Fig. 1 is a view showing an embodiment of the present invention, and is a front view of a toothbrush 1.

Fig. 2 is a side view of the toothbrush 1.

Fig. 3 is a rear view of the toothbrush 1.

Detailed Description

Next, an embodiment of the toothbrush of the present invention will be described with reference to fig. 1 to 3.

The following embodiments are illustrative of one embodiment of the present invention, and are not intended to limit the present invention, and may be arbitrarily modified within the scope of the technical idea of the present invention. In the drawings below, the scale, number, and the like of each structure are different from those of an actual structure in order to facilitate understanding of each structure.

Fig. 1 is a front view of the toothbrush 1. Fig. 2 is a side view of the toothbrush 1. Fig. 3 is a rear view of the toothbrush 1.

The toothbrush 1 of the present embodiment includes: a head portion 10 in which bristles are implanted and which is disposed on a front end side in a longitudinal direction (hereinafter, simply referred to as a front end side), a neck portion 20 which extends toward a rear end side in the longitudinal direction (hereinafter, simply referred to as a rear end side) of the head portion 10, and a handle portion 30 which extends toward a rear end side of the neck portion 20 (hereinafter, the head portion 10, the neck portion 20, and the handle portion 30 are collectively referred to as a handle body 2).

The brush head portion 10 has a bristle surface 11 on one side in the thickness direction. In the following, the side of the flocked surface 11 in the thickness direction is referred to as a front surface side in a front direction, the side opposite to the flocked surface is referred to as a back surface side, and a direction perpendicular to the thickness direction and the longitudinal direction is referred to as a side surface direction. A plurality of implantation holes 12 are formed in the implantation surface 11. A tuft (not shown) having bristles is planted in the planting hole 12.

The width W1 of the brush head portion 10, that is, the width W1 in the side direction parallel to the bristle surface 11 on the front side and perpendicular to the longitudinal direction (hereinafter, simply referred to as width) is not particularly limited, and is preferably 7mm to 13mm, for example. If the lower limit value is more than the lower limit value, the area of the planted hair bundle can be fully ensured; if the upper limit value is less than the above-mentioned upper limit value, the operability in the oral cavity can be further improved.

The length L1 of the brush head portion 10 is not particularly limited, and is preferably 10mm or more and 33mm or less, for example. When the length L1 is equal to or greater than the lower limit value, the area of the implanted hair bundle can be sufficiently secured; if the upper limit value is less than the above-mentioned upper limit value, the operability in the oral cavity can be further improved.

The thickness t1 of the brush head portion 10 may be determined in consideration of the material, etc., and is preferably 2.0mm or more and 4.0mm or less. If the thickness t1 is equal to or greater than the lower limit value, the strength of the brush head portion 10 can be further improved; when the amount is equal to or less than the upper limit, the accessibility to the deep part of the dentures can be improved and the operability in the oral cavity can be further improved.

The length L2 of the brush neck portion 20 is preferably 40mm to 70mm so that the brush neck portion 20 can contact the lips when the brush head portion 10 is inserted into the oral cavity.

The width W2 of the brush neck portion 20 is formed to gradually increase from a position at which the width becomes a minimum toward the rear end side. The brush neck portion 20 in the present embodiment is formed such that the width W2 gradually increases from the position 21 at which the width becomes the minimum toward the rear end side. The brush neck portion 20 is formed such that the thickness t2 gradually increases from the minimum position 21 toward the rear end side.

The width and thickness of the position 21 that is the smallest are preferably 3.0mm to 4.5 mm. If the value is equal to or higher than the lower limit value, the strength of the brush neck portion 20 can be further increased; when the upper limit value or less is set to the above-described upper limit value, the lips are easily closed, the accessibility of the teeth can be improved, and the operability in the oral cavity can be further improved. The width W2 and the thickness t2 of the brush neck portion 20 formed to gradually increase from the position 21 that becomes the minimum toward the rear end side may be determined in consideration of the material and the like.

In the present embodiment, as shown in fig. 2, the front surface side of the brush neck portion 20 extends parallel to the bristle surface 11. The back surface side of the brush neck portion 20 gradually inclines downward away from the bristle surface 11 toward the rear end side with the rear end (position 21) of the brush head portion 10 as a starting point.

A boundary 31 between the neck portion 20 and the handle portion 30 on the back side is formed by a ridge line at the intersection of the curved surface 32 and the curved surface 33, and in a side view, the curved surface 32 is disposed on the front end side of the boundary 31 and has a center of curvature on the back side, and the curved surface 33 is disposed on the rear end side of the boundary 31 and has a center of curvature on the back side. The front end side of the curved surface 32 is in contact with the back surface side of the brush neck portion 20.

A boundary 36 between neck portion 20 and handle portion 30 on the front side is formed by a curved surface 38 and a curved surface 37, and in a side view, curved surface 38 is disposed on the front end side of boundary 36 and has a center of curvature on the front side, and curved surface 37 is disposed on the rear end side of boundary 36 and has a center of curvature on the rear side. The curved surface 37 is in contact with a third pole section 51 described later.

The position of the brush neck portion 20 on the rear end side is defined by the

boundaries

31, 36. When the positions of the

boundaries

31 and 36 are different in the longitudinal direction, the length L2 of the brush neck portion 20 is defined by the distance from the position 21 to the boundary 31, which is long. The details of the boundary 31 will be described later.

As shown in the front view of fig. 1 and the rear view of fig. 3, the brush holder portion 30 includes a plurality of (2 in the present embodiment) first pole sections (side pole sections) 41 and second pole sections (side pole sections) 42 that are arranged along the longitudinal direction and whose width in the side direction changes continuously and bilaterally symmetrically, and a first minimum section (side minimum section) 43 that is arranged between the first pole section 41 and the second pole section 42 and whose width in the side direction changes continuously and bilaterally symmetrically. The first and

second pole sections

41 and 42 each have a circular arc contour in which the distance from the center C gradually increases as the distance from the center C increases toward the position in the longitudinal direction where the distance from the center C becomes maximum. The first minimum portion 43 has a circular arc contour in which the distance from the center C gradually decreases toward a position in the longitudinal direction where the distance from the center C becomes the minimum.

As shown in fig. 2 in a side view, the brush holder portion 30 includes: a plurality of (2 in the present embodiment) third pole sections (front-side pole sections) 51 and fourth pole sections (front-side pole sections) 52 that are arranged near the positions of the first pole section 41 and the second pole section 42 in the longitudinal direction on the front side and have continuously changing thicknesses, and a second minimum section (front-side minimum section) 53 that is arranged between the third pole section 51 and the fourth pole section 52 and has continuously changing thicknesses. The third and

fourth pole sections

51 and 52 each have a circular arc profile in which the thickness gradually increases toward a position in the longitudinal direction where the thickness becomes maximum. The second pole-piece 53 has a circular arc profile in which the thickness gradually decreases toward the position in the longitudinal direction where the thickness becomes the minimum.

The third pole section 51 is disposed on the tip side of the first pole section 41 and serves as a finger contact portion. The fourth pole section 52 is disposed on the tip side of the second pole section 42.

The brush holder portion 30 has a straight section 54 that is arranged closer to the rear end side than the boundary 31 on the back surface side and extends substantially linearly from the boundary 31 toward the rear end side in a side view. The front end side of the straight portion 54 is in contact with the curved surface 33.

As shown in fig. 2, the boundary 31 is disposed closer to the tip side than the third pole section 51 located closest to the tip side. The boundary 31 has a fifth pole section (back side pole section) 55 whose thickness varies continuously. The fifth pole section 55 is formed in a shape in which the thickness continuously increases on the back side in accordance with the

curved surfaces

32 and 33 having the curvature center on the back side.

The length L3 of the brush holder portion 30 is not particularly limited, and is, for example, 90 to 200 mm.

The widths of the first pole section 41 and the second pole section 42 are preferably 10.5mm to 14 mm. The width of the second pole section 42 is preferably larger than the width of the first pole section 41. The width of the first extremely small portion 43 is preferably 8.5mm or more and 10.5mm or less.

The difference between the width of the first extremely small portion 41 and the width of the first extremely small portion 43 is preferably 1.5mm to 3.0 mm.

The difference between the width of the second pole section 42 and the width of the first extremely small section 43 is preferably 2.5mm or more and 4.5mm or less.

The ratio of "width of the first extremely small portion 41"/"width of the first extremely small portion 43" is preferably 1.1 or more and 1.3 or less.

The ratio of "width of second pole section 42"/"width of first pole section 43" is preferably 1.3 or more and 1.5 or less.

The thickness of the third and

fourth pole sections

51 and 52 is preferably 8mm to 11 mm. The thickness of the fourth pole section 52 is preferably larger than the thickness of the third pole section 51. The width of the second small part 53 is preferably 6mm to 8 mm.

The difference between the thickness of the third pole section 51 and the thickness of the second pole section 53 is preferably 1.5mm to 3.0 mm.

The difference between the thickness of the fourth large section 52 and the thickness of the second small section 53 is preferably 2.5mm to 4.5 mm.

The ratio of "thickness of the third pole section 51"/"thickness of the second pole section 53" is preferably 1.1 or more and 1.5 or less.

The ratio "thickness of the fourth pole large portion 52"/"width of the second pole small portion 53" is preferably 1.3 or more and 1.7 or less.

The brush holder body 2 is integrally formed in a long shape as a whole, and is obtained by injection molding using resin as a material, for example. The brush holder body 2 has a hard portion formed of a hard resin and a soft portion formed of a soft resin. In the brush handle 2, the brush head portion 10 and the brush neck portion 20 are formed of a hard portion.

In the handle body 2, the handle portion 30 has a soft portion 61 and a soft portion 62, the soft portion 61 is provided at a position including the third pole section 51 on the front surface side, and the soft portion 62 extends from the rear end portion on the front surface side to the vicinity of the boundary 31 on the rear surface side.

The soft portions 61 include

soft portions

61a, 61b, and 61c arranged at intervals in the longitudinal direction. The soft portions 61a to 61c are provided to protrude from the surrounding hard portions by, for example, about 0.5 mm. The shape of the protrusion may be a concave-convex shape having a groove in the width direction.

Examples of the hard resin include resins having a flexural modulus of elasticity (JIS7171) of 1000MPa to 2200MPa, for example, polypropylene resins (PP), polyacetal resins (POM), polystyrene resins (PS), polyethylene terephthalate resins (PET), polybutylene terephthalate resins (PBT), acrylonitrile-butadiene-styrene resins (ABS), polyarylate resins (PAR), polycarbonate resins (PC), and acrylonitrile-styrene resins (AS). Among them, a polypropylene resin is preferable as a general-purpose resin in view of cost.

The soft resin is preferably a soft resin having a shore a hardness of 90 or less, and more preferably a soft resin having a shore a hardness of 50 to 80, as an example. Examples of the soft resin include elastomers (e.g., olefin elastomers, styrene elastomers, polyester elastomers, polyurethane thermoplastic elastomers, etc.), and silicones.

The tufts are formed by bundling a plurality of bristles. The length (hair length) from the hair-planted surface 11 to the tip of the bundle of bristles is determined in consideration of the stiffness of the bristles required for the bundle of bristles, and is set to 6 to 13mm, for example. All tufts may have the same tuft length or may have tuft lengths different from each other.

The thickness of the tufts (tuft diameter) can be determined in consideration of the stiffness of the bristles required for the tufts, and is set to 1 to 3mm, for example. All of the tufts may have the same tuft diameter or may have different tuft diameters from each other.

Examples of the bristles constituting the bundle of bristles include bristles (tapered bristles) in which the tips gradually decrease in diameter as they go to the tips, bristles (straight bristles) in which the diameters thereof are substantially the same from the bristle surface 11 toward the tips, and the like. The straight hair may be straight hair having a tip substantially parallel to the plane of the implanted surface 11, or straight hair having a hemispherical rounded tip.

Examples of the material of the bristles include polyamides such as 6-12 nylon (6-12NY) and 6-10 nylon (6-10NY), polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN) and polybutylene naphthalate (PBN), polyolefins such as polypropylene (PP), polyolefin elastomers such as polyolefin elastomers and styrene elastomers. These resin materials may be used alone in 1 kind or in combination of 2 or more kinds. Further, as the bristles, there may be mentioned polyester bristles having a multiple core structure having a core portion and at least 1 or more layers of sheath portions provided outside the core portion.

The cross-sectional shape of the brush is not particularly limited, and may be circular such as a perfect circle and an ellipse, polygonal, star-shaped, clover-shaped, or the like. The cross-sectional shapes of all the bristles may be the same or different.

The thickness of the brush may be determined in consideration of the material, and when the cross section is circular, it may be set to 6 to 9 mils (1 mil: 1/1000 inch: 0.025mm), for example. In addition, a plurality of bristles having different thicknesses may be arbitrarily combined for use in consideration of a feeling of use, a brushing feeling, a cleaning effect, durability, and the like.

The operation of the above-mentioned toothbrush in a palm-held or pen-held manner will be described.

(palm-held type case)

In the palm grip type grip, the middle finger is held in contact with the peripheral direction of the first minimum portion 43 and the second minimum portion 53 provided in the brush holder portion 30, and thus the ring finger and the little finger are naturally brought into contact with the peripheral direction of the second maximum portion 42 and the fourth maximum portion 52 in a close contact manner, and stable holding performance can be obtained. Further, since the index finger and the thumb naturally contact the first pole section 41 and the third pole section 51 in a close contact manner, more stable gripping performance can be obtained. Thus, even if the brush handle body is thin, a sufficient feeling of attachment and stability can be obtained during holding.

Further, since the substantially straight portion 54 is provided on the back side of the brush holder portion 30, the feeling of adhesion to the fingers is not excessive as compared with the case where both the front side and the back side are constituted by the extremely large portions, and even if the brush holder body is thin, a moderate feeling of adhesion can be obtained at the time of holding. Further, since the brush head portion 10 is arranged on a substantially extended line of the straight portion 54, an error in the relative positional relationship with the brush head portion 10 when the brush holder portion 30 is held is reduced, the brush head portion 10 can be accurately inserted into a desired portion in the mouth, and the target portion can be easily ground and brushed.

(case of holding pen type)

When the brush is gripped with a pen, the first extremely large part 41, the third extremely large part 51, and the straight part 54 provided in the brush holder part 30 are fixed and held with the thumb, the index finger, and the middle finger, whereby the extremely large parts can be stuck to each other so as to sink into the finger in contact with each other, and a stable feeling can be obtained. Further, a fifth extremely large section 55 is provided at a boundary 31 between the brush neck section 20 and the brush holder section 30 on the back side, and the fifth extremely large section 55 is disposed on the tip side of the third extremely large section 51 closest to the tip side, whereby the finger in contact is less likely to slip. Thus, even if the brush handle body is thin, a sufficient feeling of adhesion and a sufficient feeling of stability can be obtained when the brush handle body is held.

In the above-described toothbrush 1, since the soft portion 61 is provided in the third pole section 51 so as to protrude from the surrounding hard portion, the effect of suppressing slippage (feeling of stability during brushing) can be further enhanced by fitting the third pole section so as to sink into the fingers. Further, by disposing the soft portion 61 in the third pole portion 51, visibility and tactile sensation recognition of the finger placement position and the reaching position of the toothbrush are improved. Further, in the above-described toothbrush 1, since the plurality of soft portions 61 are arranged at intervals in the longitudinal direction, the brushing pressure applied to the teeth and the gums can be easily controlled even if a certain force is applied by appropriately selecting the finger placement position.

Further, since the brush neck portion 20 gradually becomes thicker from the brush head portion 10 toward the handle portion 30 by the fifth extremely large portion 55, it is less likely to bend when a load is applied downward to the brush head portion 10. Therefore, in the toothbrush 1 of the present embodiment, the brushing pressure can be appropriately controlled by appropriate bending of the brush neck portion 20.

While preferred embodiments of the present invention have been described above with reference to the drawings, it goes without saying that the present invention is not limited to the above examples. The shapes, combinations, and the like of the respective constituent members shown in the above examples are examples, and various modifications can be made based on design requirements and the like without departing from the spirit of the present invention.

For example, in the above-described embodiment, the configuration in which the toothbrush 1 includes the hard portion and the soft portion is exemplified, but the present invention is not limited to this configuration, and a configuration in which only the hard portion is provided may be applied.

In the above embodiment, the configuration in which the soft portion 61 has three soft portions 61a to 61c is exemplified, but one to two, or four or more soft portions may be used. In the above embodiment, the three soft portions 61 are all in the shape of an ellipse, but may be in the shape of a circle, a polygon, or a combination of different shapes.

In the above embodiment, the configuration in which the two first pole sections 41 and the second pole section 42, and the two third pole sections 51 and the fourth pole section 52 are provided is exemplified, but the configuration is not limited to this, and three or more may be provided. In this case, the first minimum portion may be disposed between the first and second adjacent pole sections, and the second minimum portion may be disposed between the third and fourth adjacent pole sections.

Industrial applicability

The invention is applicable to toothbrushes.

Description of the symbols

1 … toothbrush, 10 … brush head portion, 20 … brush neck portion, 30 … brush handle portion, 41 … first pole major portion (side face side pole major portion), 42 … second pole major portion (side face side pole major portion), 43 … first minimum portion (side face side minimum portion), 51 … third pole major portion (front face side pole major portion), 52 … fourth pole major portion (front face side pole major portion), 53 … second minimum portion (front face side minimum portion), 54 … straight portion, 55 … fifth pole major portion (rear face side pole major portion), 61a to 61C … soft portion, and C … width direction center.

Claims

1. A toothbrush, comprising:

a brush head portion which is arranged on the front end side in the long axis direction and is formed by implanting hair bundles on a hair implanting surface;

a brush neck portion extending from a rear end side of the brush head portion; and

a brush handle part extending from the rear end side of the brush neck part,

the brush handle portion has:

a plurality of side surface side pole sections which are arranged along the long axis direction in a front view when viewed from a front direction perpendicular to the hair-planted surface, and in which widths in side surface directions perpendicular to the long axis direction and the front direction are continuously changed in bilateral symmetry;

a side surface side extremely small portion which is arranged between the side surface side extremely small portions and whose width in the side surface direction continuously changes bilaterally symmetrically;

a plurality of front side pole sections which are arranged along the longitudinal direction on the hair-planted surface side in the front direction as viewed from the side direction and have continuously changing thicknesses;

a front-side extremely small portion which is arranged between the front-side extremely large portions and in which the thickness continuously changes; and

a straight step portion that is disposed closer to the rear end side than a boundary between the brush neck portion and the brush shank portion on a rear surface side opposite to the bristle planting surface in the front direction, and that extends substantially linearly from the boundary toward the rear end side,

the boundary has a rear-side pole major part that is arranged closer to the tip side than the front-side pole major part located closest to the tip side, and has a continuously changing thickness.

2. The toothbrush of claim 1,

the outer peripheral surface of the brush holder portion has a hard portion formed of a hard resin and a soft portion formed of a soft resin,

the front-side extremely large portion disposed closest to the tip side includes the soft portion.

3. The toothbrush of claim 2,

the soft portion of the front side extremely large portion disposed closest to the distal end side protrudes from the hard portion around the soft portion.

4. The toothbrush of claim 2 or 3,

a plurality of the soft portions of the front-side extremely large portion disposed closest to the distal end side are disposed at intervals in the longitudinal direction.

5. The toothbrush according to any one of claims 1 to 4,

the minimum thickness of the brush head part is more than 2mm and less than 4mm,

the minimum thickness of the brush neck portion in the front direction and the minimum width of the brush neck portion in the side direction are respectively 3.0mm to 4.5 mm.