TW202243613A - toothbrush - Google Patents

Abstract

The present invention provides a toothbrush with which a fit with a cleaning target is achieved without depending on brushing methods and techniques. A rigid section has a head section, a grip section, and a neck section. Assuming a position at a distal-end-side end section of the neck section to be A and a position at a rear-end-side end section of the neck section to be B, at position A, the length of the neck section in the thickness direction and the length thereof in the width direction are both 3.0 to 4.3 mm. The ratio of the length of the neck section at position A in the width direction to the length of the neck section at position B in the width direction is 0.30 to 0.60. The ratio of the length of the neck section at position A in the thickness direction to the length of the neck section at position B in the thickness direction is 0.30 to 0.60, and at least one of the curve of a brush body in the width direction measured by a method ([alpha]) and the curve of the brush body in the thickness direction measured by a method ([beta]) has the origin of the curve in the grip section.

Description

toothbrush

The present invention relates to a toothbrush. This application claims priority based on Japanese Patent Application No. 2021-081747 for which it applied in Japan on May 13, 2021, and uses the content for this application.

In a thin-necked toothbrush with a narrow neck from the viewpoint of operability in the oral cavity, etc., the front end region of the neck is formed thinner, and in order to ensure strength, the vicinity of the boundary between the neck and the grip part is formed thinner than the front end of the neck. Thick, thereby avoiding the behavior of the neck flexing from the rear end side.

In addition, Patent Document 1 discloses a toothbrush in which operability is achieved by making the brush body an S-shape when viewed from the side, and making the bent shape close to a "straight" toothbrush. The shape of the main body of the brush is high and cleans the space between the teeth. [Prior art literature] [Patent Document]

[Patent Document 1] International Publication No. 2018/079114

[Problem to be Solved by the Invention]

There are many unevenness in the gap between the teeth or the neck of the teeth in the oral cavity. Therefore, in order to perform brushing with high gap cleaning performance, it is important to contact the bristles from an appropriate angle in accordance with the unevenness. However, the deflection direction of the toothbrush disclosed in Patent Document 1 is limited to the thickness direction of the head, and it cannot be said that the cleaning performance and operability for the spaces between teeth are sufficient.

The inventors of the present invention have conducted research and found that in the toothbrush as described above, the movement of the head becomes more free when brushing the teeth due to the thinning of the neck. There are still differences in tooth brushing skills. In order to match the unevenness and touch the bristles from an appropriate angle, it is more ideal to have a structure that can easily move the head to various angles than to limit the deflection direction and amount.

The present invention is made in consideration of the above aspects, and an object thereof is to provide a toothbrush that can achieve adaptability to the cleaning object regardless of brushing methods and skills. [Means to solve the problem]

<1> A toothbrush is provided, which is characterized in that it has: a hair-planting part including a plurality of hair bundles; and a brush body extending in a long axis direction, the brush body having a hard part formed of hard resin, and the hard part has: a head The part is located on the front end side in the direction of the long axis, and the hair-planting part is provided on the hair-planting surface; the grip part is located on the rear end side in the direction of the long axis than the head; and the neck is located at the Between the head and the grip, let the position of the end on the front end side in the direction of the long axis of the neck be A, and set the position of the end of the neck in the direction of the long axis to A. When the position of the end portion on the rear end side is B, the direction perpendicular to the flocking surface is defined as the thickness direction, and the direction parallel to the flocked surface and perpendicular to the thickness direction is defined as the width direction , the length in the thickness direction and the length in the width direction of the neck at the position A are both more than 3.0 mm and less than 4.3 mm, and the length of the neck at the position A is The ratio of the length in the width direction to the length in the width direction of the neck at the position B is not less than 0.30 and not more than 0.60, and the length of the neck at the position A in the thickness direction is The ratio of the length of the brush body to the length of the neck in the thickness direction at the position B is not less than 0.30 and not more than 0.60, and the brush body measured by the following method (α) At least one of the bending in the width direction and the bending in the thickness direction of the brush main body measured by the following method (β) starts from the grip portion. Method (α): Divide 40 to be the length of the grip part in the direction of the major axis from the end of the grip part on the front end side in the direction of the long axis to the rear end side. The position of % is fixed, and the height of the front end of the brush body in this state is taken as the reference height. A load of 200 g is applied to the central position in the long axis direction, and the displacement (in mm) in the width direction between the starting position of bending and the front end of the brush body relative to the reference height after 10 seconds is defined as The bending length was measured. Method (β): Divide 40, which is the length of the grip part in the direction of the long axis from the end of the grip part on the front end side in the direction of the long axis to the rear end side. The position of % is fixed, and the height of the front end of the brush body in this state is taken as the reference height. A load of 200 g is applied to the central position in the long axis direction, and the displacement (in mm) in the thickness direction between the starting position of bending and the front end of the brush body relative to the reference height after 10 seconds is defined as The bending length was measured.

<2> The toothbrush as described in <1> whose bending length in the said width direction and the bending length in the said thickness direction are both 6.0 mm or more and 11.0 mm or less.

<3> The toothbrush according to <1> or <2>, wherein the torque of the head when the head is rotated about an axis extending in the direction of the major axis with a torque of 20 N·cm The rotation angle is not less than 30° and not more than 50°.

<4> The toothbrush according to any one of <1> to <3>, wherein the length in the thickness direction of the neck is D mm, and the length in the width direction is W mm. , set the value represented by W×D3 at position A as WD3(A) mm4, set the value represented by W×D3 at position B as WD3(B) mm4, and set the value represented by D×W3 at position A The value indicated is set to DW3(A) mm4, and the value represented by D×W3 at position B is set to DW3(B) mm4, then WD3(B) is more than 1200 mm4 and less than 6500 mm4, and WD3(A)/ The value represented by WD3(B) is 0.01 to 0.20, the DW3(B) is 1200 mm4 to 6500 mm4, and the value represented by DW3(A)/DW3(B) is 0.01 to 0.20.

<5> The toothbrush according to any one of <1> to <4>, wherein, in a continuous region of at least 20% of the length of the grip in the direction of the long axis of the grip, the Both the length in the thickness direction and the length in the width direction are not less than 4.5 mm and not more than 8.0 mm.

<6> The toothbrush according to any one of <1> to <5>, wherein if the position of the end portion on the front end side in the longitudinal axis direction of the grip portion is C, the grip The end portion of the front end side of the grip part toward the rear end side, the position that becomes 50% of the length of the grip part in the long axis direction is set to D, and the position of the grip part The length in the thickness direction is set to D mm, the length in the width direction is set to W mm, the value represented by W×D3 at position C is set to WD3(C) mm4, and the W×D3 at position D is set to Set the value represented by D3 to WD3(D) mm4, set the value represented by D×W3 at position C to DW3(C) mm4, and set the value represented by D×W3 at position D to DW3(D ) mm4, WD3(C) is above 410 mm4 and below 4000 mm4, the value expressed by WD3(C)/WD3(D) is above 0.35 and below 2.0, and DW3(C) is above 410 mm4 and below 4000 mm4, The value represented by DW3(C)/DW3(D) is not less than 0.35 and not more than 2.0.

<7> The toothbrush according to <6>, wherein the length in the width direction of the grip portion at the position C is relative to the length in the width direction of the grip portion at the position D The length ratio is not less than 0.65 and not more than 1.30, the length of the grip portion at the position C in the thickness direction relative to the length of the grip portion at the position D in the thickness direction The ratio is not less than 0.65 and not more than 1.30.

<8> The toothbrush according to <6> or <7>, wherein both the length in the thickness direction and the length in the width direction of the neck are constant or gradually from the front end side to the rear end side diameter expansion, the neck has at least one of a length in the thickness direction and a length in the width direction that is larger than the distance between the position C and the position D of the gripping portion. A position where the length in the thickness direction or the length in the width direction is large, and the position E closest to the front end side among the positions is located closer to the front end side than the position B by an amount of 3 mm or more .

<9> The toothbrush according to any one of <1> to <8>, wherein at least a part of the grip part is covered with a soft part made of soft resin, and the distance from the front end side of the grip part is In the continuous region of at least 20% or more of the length of the grip portion in the direction of the long axis from the end toward the rear end side, if the side view of the grip portion is viewed in the width direction The length in the thickness direction including the soft part is De, the length in the thickness direction of the grip part in the side view is Dh, and the length in the thickness direction is The length in the width direction including the soft part in the front view of the grip part is We, and the length in the width direction of the grip part in the front view is Wh, Then, the value represented by Dh/De is 0.75 or less, and the value represented by Wh/We is 0.75 or less. [Effect of the invention]

In the present invention, in the toothbrush, adaptability to the object to be cleaned is obtained without depending on the brushing method and technique.

Hereinafter, an embodiment of the toothbrush according to the present invention will be described with reference to FIGS. 1 to 4 . In addition, the following embodiment shows an aspect of this invention, does not limit this invention, and can change arbitrarily within the range of the technical thought of this invention. In addition, in the following drawings, in order to make each structure easy to understand, the actual structure differs from the scale, number, etc. in each structure.

In addition, in the following description, the side (the side opposite to the flocking surface) of the head 3 described later is provided with the flocking surface 3 a as the front side of the toothbrush 1, and the flocking surface 3 a of the head 3 faces The side opposite to this side is the back side of the toothbrush 1 . In addition, the direction parallel to the flocking surface 3a and extending the brush body 2 described later is defined as the major axis direction, the direction parallel to the flocking surface 3a and perpendicular to the major axis direction is defined as the width direction of the toothbrush 1, and the direction parallel to the flocking surface 3a is defined as the width direction of the toothbrush 1. The direction perpendicular to 3a will be described as the thickness direction of the toothbrush 1 . In addition, the side where the head 3 is provided in the long axis direction (the head 3 side) is referred to as the front end side, and the side where the grip part 5 is provided (the grip part 5 side) is referred to as the rear end side. suitable for explanation.

Fig. 1 is a diagram showing the structure of a toothbrush 1, and is a side view of the toothbrush 1 viewed in the width direction. Fig. 2 is a front view of the toothbrush 1 viewed from the hair-implanted surface 3a side in the thickness direction. In addition, in FIG. 2, illustration of the hair transplant part 40 is abbreviate|omitted.

As shown in FIGS. 1 and 2 , the toothbrush 1 according to this embodiment includes a brush body 2 including a resin molded body formed in an elongated shape as a whole, and a hair-implanted part 40 .

The brush body 2 has: a head area 3R, which is located at the front end side and has a flocking surface 3a; a grip area 5R, which is arranged on the rear side of the brush head area 3R; and a neck area 4R, which is arranged between the head area 3R and the grip between zone 5R. The toothbrush 1 can clean the inside of the oral cavity by the hair-implanted part 40 having a plurality of hair bundles (not shown) implanted on the hair-implanted surface 3 a of the head region 3R.

The brush main body 2 has a hard part 60 made of hard resin and a soft part 70 made of soft resin. The hard portion 60 extends in the long axis direction. The hard portion 60 forms at least a part of the head region 3R, the neck region 4R, and the grip region 5R. The soft portion 70 forms a part of the grip region 5R.

The soft part 75 covers a part of the hard part 60 in the grip region 5R.

The hard part 60 includes: the head 3 located in the head region 3R, the neck 4 located in the neck region 4R, and the grip part 5 located in the grip region 5R.

As the hard resin, as an example, a resin having a flexural modulus (Japanese Industrial Standards (JIS) 7171) of 1000 MPa or more and 2800 MPa or less is used as an example, and it is preferable to use, for example, polypropylene ( Polypropylene, PP) resin, polyacetal (Polyoxymethylene, POM) resin, polybutylene terephthalate (Polybutylene Terephthalate, PBT) resin, etc. In addition, in terms of flexibility, the bending elastic modulus is more preferably 1000 MPa-2000 MPa, and PP resin is more preferable.

As the soft resin, the Shore A hardness is more preferably 30 or more and 80 or less. Examples of the soft resin include elastomers (for example, olefin-based elastomers, styrene-based elastomers, polyester-based elastomers, polyurethane-based thermoplastic elastomers, etc.), and silicones.

(Outline shape of the front side of the brush body) As shown in FIG. 1 , regarding the toothbrush 1 of the present embodiment, when the brush body 2 is viewed from the side, in the contour line of the front side of the brush body 2, there is a toothbrush from the rear end side of the head region 3R toward the grip region 5R side. : The first linear region L1 extends linearly from the flocking surface 3a of the head region 3R to the rear end side continuously; the first curved region F1 has a curvature center on the front side, and is convex from the rear end of the first linear region L1 The apex 51A extends to the rear end side in an arc shape; the second curved area F2 has a curvature center on the front side and extends from the apex 51A to the rear end side in an arc shape; the third curved area F3 has a curvature on the back side center, and extend from the rear end of the second curved area F2 to the rear end side; the fourth curved area F4 has a curvature center on the front side, and extends from the rear end of the third curved area F3 to the rear end side; and the fifth curved area F5 has a center of curvature on the back side and extends from the rear end of the fourth curved area F4 to the rear end side.

(Outline shape of the back side of the brush body) The toothbrush 1 according to the present embodiment has a second linear region L2 from the rear end side of the head region 3R toward the grip region 5R side in the contour line on the back side of the brush body 2 when the brush body 2 is viewed from the side. , continuously extending linearly from the back of the head 3 to the rear end side; the sixth curved area F6 has a curvature center on the front side, and extends in an arc shape from the rear end to the rear end side of the second linear area L2; The seven curved area F7 has a center of curvature on the back side, and extends in an arc shape from the rear end of the sixth curved area F6 to the apex 51B; the eighth curved area F8 has a center of curvature on the back side, and The apex 51B extends in an arc shape to the rear end side; the ninth curved area F9 has a curvature center on the front side, and extends in an arc shape from the rear end of the eighth curved area F8 to the rear end side; the tenth curved area F10, The back side has a center of curvature, and extends in an arc shape from the rear end of the ninth curved area F9 to the rear end; and the eleventh curved area F11 has a center of curvature on the front side, and extends from the rear end of the tenth curved area F10 Extends in an arc shape toward the rear end side.

The neck region 4R and the grip region 5R in a side view extend obliquely with respect to the long-axis direction in the direction toward the front side in the thickness direction as they go toward the rear end side. The first curved area F1, the second curved area F2, the third curved area F3, the fourth curved area F4, and the fifth curved area F5 are disposed at the same position as the flocking surface 3a in the thickness direction or at the same position as the flocking surface 3a in the thickness direction. 3a is closer to the front side.

(Outline shape of both sides in the width direction of the brush body) As shown in FIG. 2 , regarding the toothbrush 1 of this embodiment, when the brush body 2 is viewed from the front, with respect to the center line located at the center in the width direction and extending along the long axis direction, the outer shapes of both sides in the width direction of the brush body 2 are: Outlines are formed with line symmetry. Therefore, in the following description, the outline of one side (lower side in FIG. 2 ) in the width direction will be described. In addition, regarding the position of the center of curvature of the curved region extending in an arc shape, the case where the center side in the width direction is referred to as the inner side relative to the outer contour line, and the case where it is the opposite side to the center in the width direction is referred to as outside.

Regarding the toothbrush 1 of this embodiment, when the brush body 2 is viewed from the front, in the contour line of the width direction of the brush body 2, there is a third linear region L3 from the boundary between the head region 3R and the neck region 4R (details (described later) extends linearly toward the rear end side; the twelfth curved area F12 has a curvature center on the outside, and extends in an arc shape from the rear end of the third linear area L3 to the rear end side; the thirteenth curved area F13, at The inner side has a center of curvature, and extends in an arc shape from the rear end of the twelfth curved area F12 to the rear end side; the fourteenth curved area F14 has a curvature center on the outer side, and is backward from the rear end of the thirteenth curved area F13 The end side extends in an arc shape; and the fifteenth curved area F15 has a curvature center on the inner side and extends in an arc shape from the rear end of the fourteenth curved area F14 to the rear end side.

The boundary between the head region 3R and the neck region 4R is the position A of the front end side end of the third linear region L3. In addition, the position A coincides with the boundary between the head 3 and the neck 4 described later. The boundary between the neck region 4R and the grip region 5R is a position B where the contour line of the front view switches from the twelfth curved region F12 with the arc center on the outside to the thirteenth curved region F13 with the arc center on the inside. The position B coincides with the boundary between the neck portion 4 and the grip portion 5 to be described later. When the switching position of the outline contour line is unclear, it is set to be the position closest to the tip side where the coating of the soft resin starts. In the front view and side view, the boundary is set to be common.

The rear end side of the grip region 5R from the position B is covered with the soft part 74 over the entire circumference. In the grip region 5R, the hard portion 60 is exposed to the outside in the end portion on the rear end side and the design region 5A on the front side. Except for the end portion on the rear end side and the design region 5A, the entire circumference is covered with the soft portion 75 .

As shown in FIG. 2 , the length in the width direction of the grip region 5R has a maximum value in the thirteenth curved region F13 and a fifteenth curved region F15 and a minimum value in the fourteenth curved region F14 when viewed from the front. value.

As shown in FIG. 1 , the length in the thickness direction of the grip region 5R decreases from the maximum value shown between the apex 51A and the apex 51B to that shown between the second curved region F2 and the eighth curved region F8 when viewed from the side. the location of the minimum value. The length in the thickness direction of the grip region 5R increases from a position showing a minimum value between the second curved region F2 and the eighth curved region F8 to a position showing a maximum value between the third curved region F3 and the ninth curved region F9 s position. The length in the thickness direction of the grip region 5R decreases from the position showing the maximum value between the third curve region F3 and the ninth curve region F9 to the position showing a minimum value between the fourth curve region F4 and the tenth curve region F10 s position. The length in the thickness direction of the grip region 5R increases from a position showing a minimum value between the fourth curve region F4 and the tenth curve region F10 to a position showing a maximum value between the fifth curve region F5 and the eleventh curve region F11. After the position of the value, it decreases towards the rear end side.

In the grip region 5R, the region of the second curved region F2 from the apex 51A toward the rear end side toward the back side and the region of the eighth curved region F8 from the apex 51B toward the rear end side toward the front side constitute the user's grip region 5R. Finger contact part when holding.

FIG. 3 is a side view showing the structure of the hard portion 60 . Fig. 4 is a front view of the hard part 60 viewed from the flocking surface 3a side. As shown in FIGS. 3 and 4 , the hard portion 60 has: a head 3 , a grip portion 5 located on the rear end side of the head 3 in the longitudinal direction, and a grip portion 5 located between the head 3 and the grip portion 5 . Between the neck4.

(head 3) The head 3 is a part for brushing the oral cavity with a plurality of hair bundles, and as shown in FIG. 4 , has a substantially rectangular parallelepiped shape with rounded corners. The head 3 has a substantially quadrangular flat plate shape with four corners cut by curved lines when viewed from the front. In this embodiment, the boundary between the head 3 and the neck 4 is the end point of the curve forming the chamfer on the side of the neck 4 in the front view shape of the head 3, that is, the position where the bending direction of the curve forming the chamfer changes. a.

The head part 3 has the flocking surface 3a on the front side. On the hair-planting surface 3a, a plurality of hair-planting holes 6 are arranged in a row. The shape and diameter of the hair-planting hole 6 are not particularly limited. Hair bundles constituting the hair-implanted portion 40 are respectively implanted in the hair-implantation holes 6 .

The head 3 is not covered by the soft part 70 . That is, the entire head portion 3 is exposed. The header region 3R includes the header 3 .

The hair bundles are planted in each hair-planting hole 6 by bundling and folding a plurality of bristles (filaments) in half, and clamping a metal anti-shedding tool called a flat wire (not shown) in between. And push into the hair-planting hole 6. The shape of the head part 3 is not specifically limited, For example, the flocking surface 3a on the front side and the surface on the back side form flat and parallel surfaces.

The shape of the head 3 is not particularly limited as long as it has a shape or size that facilitates brushing the oral cavity, and for example, it may be a shape that gradually narrows in width from the base end side toward the front end side. In addition, the head 3 may have a tapered shape whose thickness gradually becomes thinner from the base end side toward the front end side, or may have a shape in which the central portion of the back side of the head 3 is raised and has an arc.

The width of the head portion 3 is not particularly limited, but is preferably not less than 7 mm and not more than 16 mm, for example. If it is more than the said lower limit, the area which a hair bundle is implanted can fully be ensured, and if it is below the said upper limit, the operability in an oral cavity can be further improved. Furthermore, if the width of the head 3 is a wide head with a width of 12 mm or more, when cleaning based on the rolling (rolling) method/Bass (Bass) method described later, it is easy to clean the head 3. Twist to apply force.

The length in the long axis direction of the head portion 3 is not particularly limited, and is preferably, for example, not less than 10 mm and not more than 33 mm. When the length of the head part 3 is more than the said lower limit, the area to which a hair bundle is implanted can fully be ensured, and if it is less than the said upper limit, the operability in an oral cavity can be further improved.

The thinner the length in the thickness direction of the head portion 3 is, the more operability in the oral cavity can be improved, but if it is too thin, the strength of the head portion 3 tends to be insufficient. Therefore, as an example, the length in the thickness direction of the head portion 3 is set within a range of not less than 2.5 mm and not more than 4.5 mm. The length in the thickness direction of the head portion 3 is more preferably not less than 2.5 mm and not more than 4.0 mm. Further, the length in the thickness direction of the head portion 3 is preferably not less than 2.5 mm and not more than 3.7 mm. The lower limit of the length in the thickness direction of the head portion 3 is preferably 2.5 mm or more. The upper limit of the length in the thickness direction of the head portion 3 is preferably at most 4.5 mm, more preferably at most 4.0 mm, and still more preferably at most 3.7 mm.

(neck 4) The neck 4 is a portion arranged between the grip 5 and the head 3 and connecting the grip 5 and the head 3 . The length in the long axis direction of the neck 4 is preferably from 35.0 mm to 50.0 mm, more preferably from 37.0 mm to 48.0 mm. The lower limit of the length in the long axis direction of the neck portion 4 is preferably at least 36.0 mm, more preferably at least 37.0 mm. The upper limit of the length in the long axis direction of the neck portion 4 is preferably at most 50.0 mm, more preferably at most 48.0 mm. Both the length in the thickness direction and the length in the width direction of the neck 4 are constant or gradually increase in diameter from the front end to the rear end. In FIG. 2 , when viewed from the front, the contour of the front end side of the neck 4 has a constant width formed by the third linear region L3. The length in the major axis direction of the third linear region L3 is preferably not less than 18.0 mm and not more than 35.0 mm, more preferably not less than 20.0 mm and not more than 30.0 mm. The lower limit of the length in the major axis direction of the third linear region L3 is preferably at least 18.0 mm, more preferably at least 20.0 mm. The upper limit of the length in the major axis direction of the third linear region L3 is preferably 35.0 mm or less, more preferably 30.0 mm or less. When viewed from the front, the contour of the neck 4 on the rear side of the third linear region L3 is formed by the twelfth curved region F12. The neck portion 4 formed by the twelfth curved area F12 gradually increases in length in the width direction toward the rear end side until the position B of the end portion on the rear end side. That is, the length in the width direction of the neck portion 4 becomes the largest at the position B. As shown in FIG. Position B is the boundary between the neck 4 and the grip 5 .

When viewed from the side, the contour of the front side of the neck 4 is formed by the first curved area F1. The contour of the front side of the neck 4 gradually extends toward the front side as it goes toward the rear end side. The contour of the back side of the neck 4 is formed by a sixth curved area F6. The contour of the back side of the neck 4 gradually extends toward the front side as it goes toward the rear end side. The length of the first curved area F1 toward the front side as it goes toward the rear end side is longer than the length of the sixth curved area F6 toward the front side as it goes toward the rear end side. Therefore, the length in the thickness direction of the neck portion 4 becomes larger toward the rear end side. Furthermore, as the contour of the front side of the neck 4, it is also possible not to form the first curved area F1 or the sixth curved area F6 from the position A, but to be connected with the first curved area F1 or the sixth curved area via a straight line area. F6 is connected. In this case, the length of the linear region is preferably 15.0 mm or less.

(grip 5) As shown in FIG. 3 , in a side view, the grip portion 5 extends in a direction toward the front side from the position C of the end portion on the front end side toward the rear end side. The position C is the same position or substantially the same position as the position B of the end portion on the rear end side of the neck 4 . It should be noted that substantially the same position is defined as being substantially the same when the position C is within the distance from the position B to a position of 0.2 mm on the rear end side in the long-axis direction. The length in the thickness direction of the grip portion 5 at the position C has a region shorter than the length in the thickness direction of the neck portion 4 . The length in the thickness direction of the grip portion 5 is shorter than the length in the thickness direction of the rear end portion of the neck portion 4 from the position C toward the rear end after temporarily increasing and then decreasing, and thereafter extends substantially constant. The grip portion 5 has a protrusion 5B protruding to the front side at the position of the design area 5A in the long-axis direction. The end surface on the front side of the protrusion 5B is exposed in the grip region 5R. At the rear end of the grip portion 5, a protrusion 5C exposed at the rear end of the grip region 5R is provided. The length in the width direction of the grip portion 5 is preferably from 4.5 mm to 14.0 mm, more preferably from 4.5 mm to 12.0 mm, over the entire area of the grip portion 5 . The lower limit of the length of the grip portion 5 in the width direction is preferably 4.5 mm or more. The upper limit of the length in the width direction of the grip portion 5 is preferably 14.0 mm or less, more preferably 12.0 mm or less. The length in the thickness direction of the grip portion 5 is preferably from 4.5 mm to 18.0 mm, more preferably from 4.5 mm to 16.0 mm, over the entire area of the grip portion 5 . The lower limit of the length of the grip portion 5 in the thickness direction is preferably 4.5 mm or more. The upper limit of the length of the grip portion 5 in the thickness direction is preferably 18.0 mm or less, more preferably 16.0 mm or less. The length of the grip portion 5 in the long axis direction is preferably not less than 80 mm and not more than 140 mm, more preferably not less than 90 mm and not more than 130 mm. The lower limit of the length of the grip portion 5 in the long-axis direction is preferably 90 mm or more. The upper limit of the length of the grip portion 5 in the longitudinal direction is preferably 140 mm or less, more preferably 130 mm or less. This range includes the protrusion 5B and the protrusion 5C in FIGS. 3 and 4 . In addition, as described later, the grip portion 5 has a portion in which the length in the thickness direction and the length in the width direction are both 4.5 mm or more and 8.0 mm or less in the continuous region.

(Position A of the boundary between head 3 and neck 4) Both the length in the thickness direction and the length in the width direction of the neck portion 4 at the position A are 3.0 mm or more and 4.3 mm or less. When both the length in the thickness direction and the length in the width direction of the neck 4 at the position A are less than 3.0 mm, the neck 4 flexes excessively and becomes too movable. If both the length in the thickness direction and the length in the width direction of the neck portion 4 at the position A exceed 4.3 mm, sufficient deflection cannot be obtained. Moderate deflection can be realized by setting both the length in the thickness direction and the length in the width direction of the neck portion 4 at the position A to be 3.0 mm or more and 4.3 mm or less. More preferably, both the length in the thickness direction and the length in the width direction of the neck portion 4 at the position A are 3.0 mm or more and 4.0 mm or less.

The ratio of the widthwise length of neck 4 at position A to the widthwise length of neck 4 at position B is preferably 0.30 to 0.60, more preferably 0.40 to 0.50. The lower limit of the ratio of the length in the width direction of the neck 4 at the position A to the length in the width direction of the neck 4 at the position B is preferably 0.30 or more, more preferably 0.40 or more. The upper limit of the ratio of the length in the width direction of the neck 4 at the position A to the length in the width direction of the neck 4 at the position B is preferably 0.60 or less, more preferably 0.50 or less. The ratio of the thickness direction length of neck 4 at position A to the thickness direction length of neck 4 at position B is preferably 0.30 to 0.60, more preferably 0.40 to 0.50. The lower limit of the ratio of the length in the thickness direction of the neck 4 at position A to the length in the thickness direction of the neck 4 at position B is preferably 0.30 or more, more preferably 0.40 or more. The upper limit of the ratio of the length in the thickness direction of the neck 4 at position A to the length in the thickness direction of the neck 4 at position B is preferably 0.60 or less, more preferably 0.50 or less.

If the ratio of the length in the width direction of the neck 4 at position A to the length in the width direction of the neck 4 at position B, or the length in the thickness direction of the neck 4 at position A relative to position B If the length ratio in the thickness direction of the neck 4 is less than 0.30, the front end is too thin and the stress concentrates on the front end. Only the front end of the neck 4 is deflected, and the overall deflection of the neck 4 cannot be realized. Alternatively, the rear end is too thick to be linked with the grip portion 5, and only the neck 4 is flexed. On the other hand, when the ratio of lengths in the width direction or the ratio of lengths in the thickness direction exceeds 0.60, the rear end of the neck 4 becomes thinner and does not cooperate with the grip 5, and only the neck 4 as a whole flex excessively. Alternatively, the front end of the neck 4 becomes thicker, making it difficult to bend the front end of the neck 4 . Therefore, by setting the ratio of the length in the width direction and the length in the thickness direction to 0.30 or more and 0.60 or less, the entire neck 4 can be flexed in conjunction with the grip 5 . More preferably, the ratio of the length in the said width direction and the ratio of the length in the thickness direction is 0.40-0.50.

The brush body 2 (toothbrush 1) is fixed at a position that is 40% of the length in the longitudinal direction of the grip 5 from the front end (position C) of the grip 5 to the rear end. When a load of 200 g is applied to the central position in the long axis direction of the hair-implanted part 40 in the width direction, or when a load of 200 g is applied in the thickness direction, at least one of the bending in the width direction and the bending in the thickness direction One of them bends starting from the grip portion 5 . That is, when the load is applied to the position of the brush body 2, only the neck portion 4 does not bend in at least one of the width direction and the thickness direction, but bends starting from the grip portion 5 . Hereinafter, methods for obtaining the starting point position and the bending length of the bending of the brush body 2 will be described in detail for the width direction and the thickness direction, respectively.

(The starting position and bending length of the bending of the brush body 2 in the width direction) The starting point position and bending length of the bending of the brush main body 2 in the width direction were measured by the following method (α). Method (alpha): Fix a position that is 40% of the length of the grip in the longitudinal direction of the grip from the end on the front end side in the longitudinal direction of the grip to the rear end, and the front end of the brush body 2 in this state The height is the reference height. In a fixed state, a load of 200 g is further applied to the central position of the hair-planted part in the head in the width direction in the long axis direction, and the starting position of the bending in the width direction after 10 seconds and The amount of displacement (in mm) in the width direction of the front end of the brush body 2 relative to the reference height was measured as a bending length. Specifically, in this embodiment, the starting point position and bending length of the bending of the brush main body 2 in the width direction are measured as follows. As shown in FIG. 2 , with respect to the brush body 2 , the grip portion 5 is fixed using a jig 100 so that the width direction becomes the up-down direction. The clip 100 fixes a position P1 that is 40% of the length of the grip 5 in the longitudinal direction from the front end (position C) of the grip 5 to the rear. At this time, the height of the front end of the brush body 2 is defined as a reference height H0. Next, a 200-g weight 102 was suspended at the position S, and the height H1 of the starting position of the bending of the brush body 2 and the tip of the brush body 2 after 10 seconds was measured. The position S is the center position in the longitudinal axis direction of the hair-implanted part 40 in the head part 3. As shown in FIG. The central position in the long axis direction of the so-called hair planting portion 40 means the position between the position of the outer edge of the front end side and the position of the outer edge of the rear end side in the long axis direction among the outer edges of the plurality of hair planting holes 6. central location. Then, calculate the displacement amount (in mm) from the height H0 to the height H1. The measurement was performed five times, and the average value of the displacement was obtained as the bending length in the width direction of the brush body 2 .

(The starting position and bending length of the bending of the brush body 2 in the thickness direction) The starting point position and bending length of the bending of the brush main body 2 in the thickness direction were measured by the following method (β). Method (beta): Fix a position that is 40% of the length of the grip in the longitudinal direction of the grip from the end on the front end side in the longitudinal direction of the grip to the rear end, and the front end of the brush body 2 in this state The height is the reference height, and in a fixed state, a load of 200 g is further applied to the central position of the long axis direction of the hair-planted part in the head in the width direction, and the starting position of the bending in the thickness direction after 10 seconds is compared with the brush The amount of displacement (in mm) in the thickness direction of the front end of the main body 2 relative to the reference height was measured as a bending length. Specifically, in this embodiment, the starting point position and bending length of the bending of the brush main body 2 in the thickness direction are measured as follows. As shown in FIG. 1 , with respect to the brush main body 2 , the grip portion 5 is fixed using a jig 100 so that the thickness direction becomes the up-down direction. The clip 100 fixes a position P1 that is 40% of the length of the grip 5 in the longitudinal direction from the front end (position C) of the grip 5 to the rear. At this time, the height of the front end of the brush body 2 is defined as a reference height H0. Next, a 200-g weight 102 was suspended at the position S, and the height H2 between the starting position of bending of the brush body 2 and the front end of the brush body 2 after 10 seconds was measured. Then, the displacement amount (in mm) from the height H0 to the height H2 is obtained. The measurement was performed five times, and the average value of the displacement was obtained as the bending length in the thickness direction of the brush body 2 .

Even when the neck 4 is thick at the position A in either the width direction or the thickness direction, and the ratio of the length of the neck 4 at the position A to the length of the neck 4 at the position B exceeds 0.60, Flexibility cannot be realized at the front end of the neck 4 either. In addition, even if the neck 4 is thick at the position B in either the width direction or the thickness direction, the ratio of the length of the neck 4 at the position A to the length of the neck 4 at the position B is less than 0.30 Down, also can't realize flexure at the rear end portion of neck 4. In particular, when the neck 4 is too thick at the position B with respect to the position A, stress is applied only to the front end of the neck 4, and the rear end of the neck 4 cannot achieve the thickness in the width direction or the thickness direction. flex. Furthermore, when the grip portion 5 is thicker than the neck portion 4 , it is impossible to realize the bending from the grip portion 5 starting from the grip portion 5 , and it is impossible to obtain a larger movable area.

Therefore, in both the width direction and the thickness direction, by setting the ratio of the length of the neck 4 at the position A to the length of the neck 4 at the position B to be 0.30 or more and 0.60 or less, in the brush body 2 , when the load is applied to the position, starting from the grip 5, the head 3, the neck 4 and the grip 5 are generated in a large movable area from the grip 5 to the width direction or the thickness direction. bending.

The maximum bending length (maximum deflection amount) of the end portion on the front end side of the brush body 2 after 10 seconds after the load is applied is independent of the starting position of the bending of the brush body 2, when the load is applied in the width direction Even when a load is applied in the thickness direction, it is preferably 6.0 mm or more and 11.0 mm or less, more preferably 7.0 mm or less and 10.0 mm or less. The lower limit of the maximum bending length (maximum deflection amount) of the end portion on the front end side of the brush body 2 10 seconds after the load is applied is preferably 6.0 mm or more, more preferably 7.0 mm or more. The upper limit of the maximum bending length (maximum deflection amount) of the end portion on the front end side of the brush body 2 10 seconds after the load is applied is preferably 11.0 mm or less, more preferably 10.0 mm or less. When the bending length is less than 6.0 mm, the user cannot feel sufficient deflection, and when the bending length exceeds 11.0 mm, the deflection becomes excessive and operability deteriorates. By setting the bending length to 6.0 mm or more and 11.0 mm or less, a sufficient amount of deflection can be expressed in the width direction and the thickness direction without deteriorating operability. Therefore, in the toothbrush 1 of the present embodiment, the head 3 can be easily moved, thereby improving the fit during brushing, which is particularly effective when the brushing method is the Fones method.

In addition, in the brush body 2, the front side and the back side of the range of 9 mm from the front end of the grip part 5 to the rear end side of the grip part are fixed, and the long axis from the front end of the head part 3 to the hair transplanted part is fixed. When the front side, back side, and side side of the range up to the central position in the direction are fixed, and in this state, the head 3 is rotated around the axis extending in the long-axis direction with a torque of 20 N·cm The rotation angle of the head 3 is preferably not less than 30° and not more than 50°, more preferably not less than 40° and not more than 50°. The lower limit of the rotation angle is preferably not less than 30°, more preferably not less than 40°. The upper limit of the rotation angle is preferably 50° or less. When the rotation angle of the head 3 when the force is applied is less than 30°, the movable range of the head 3 in the rotation direction centered on the axis extending in the major axis direction during cleaning becomes narrow. When the rotation angle of the head 3 when the force is applied exceeds 50°, the head 3 is too twisted in the rotation direction centered on the axis extending in the long-axis direction during cleaning, and cannot be obtained. Stable fit. By setting the rotation angle of the head 3 when the force is applied to 30° to 50°, sufficient twisting of the head 3 can be ensured during cleaning. Therefore, in the toothbrush 1 of the present embodiment, the bristles come into contact with the teeth at various angles during cleaning, and it is easy to obtain adaptability especially in the circle method or the Pasteur method.

In the following description, the length in the thickness direction of the hard part 60 is set to D mm, and the length in the width direction is set to W mm. In addition, if the value represented by W×D ³ at position A of the neck 4 is WD ³ (A) mm ⁴ , and the value represented by W×D ³ at position B is WD ³ (B) mm ⁴ , WD ³ (B) is preferably not less than 1200 mm ⁴ and not more than 6500 mm ⁴ , more preferably not less than 2400 mm ⁴ and not more than 5200 mm ⁴ . The lower limit of WD ³ (B) is preferably at least 1200 mm ⁴ , more preferably at least 2400 mm ⁴ . The upper limit of WD ³ (B) is preferably at most 6500 mm ⁴ , more preferably at most 5200 mm ⁴ . The values indicated by WD ³ (A) and WD ³ (B) represent values corresponding to the second moment of section at position A and position B when the neck 4 has a substantially rectangular cross section and a load is applied in the thickness direction, And it is related to the ease of deflection of the neck 4 in the thickness direction.

When WD ³ (B) is less than 1200 mm ⁴ , deflection in the thickness direction becomes excessive, and when it exceeds 6500 mm ⁴ , sufficient deflection amount in the thickness direction cannot be obtained. By setting WD ³ (B) to 1200 mm ⁴ to 6500 mm ⁴ , sufficient deflection can be obtained in the thickness direction of the neck portion 4 without becoming excessive.

The value represented by WD ³ (A)/WD ³ (B) is preferably from 0.01 to 0.20, more preferably from 0.03 to 0.06. The lower limit of the value represented by WD ³ (A)/WD ³ (B) is preferably at least 0.01, more preferably at least 0.03. The upper limit of the value represented by WD ³ (A)/WD ³ (B) is preferably at most 0.20, more preferably at most 0.06. In order to make WD ³ (A)/WD ³ (B) the above value, WD ³ (A) is preferably 80 mm ⁴ or more and 350 mm ⁴ or less, more preferably 80 mm ⁴ or more and 260 mm ⁴ or less. The lower limit of WD ³ (A) is preferably 80 mm ⁴ or more. The upper limit of WD ³ (A) is preferably at most 350 mm ⁴ , more preferably at most 260 mm ⁴ . When the value represented by WD ³ (A)/WD ³ (B) is less than 0.01, the deflection in the thickness direction of the front end of the neck 4 becomes large, and the deflection in the thickness direction of the entire grip portion 5 cannot be achieved. . Alternatively, the rear end of the neck 4 is too thick to be linked with the grip part 5, and only the neck 4 is flexed. When the value represented by WD ³ (A)/WD ³ (B) exceeds 0.20, sufficient deflection in the thickness direction cannot be achieved at the tip of the neck 4 . Alternatively, the rear end of the neck 4 is thinned, and only the entire neck 4 is flexed excessively without interlocking with the grip 5 . By setting the value represented by WD ³ (A)/WD ³ (B) to 0.01 or more and 0.20 or less, the deflection in the thickness direction of the entire grip portion 5 can be realized.

Also, if the value represented by D×W ³ at position A is DW ³ (A) mm ⁴ , and the value represented by D×W ³ at position B is DW ³ (B) mm ⁴ , then DW ³ (B) is preferably not less than 1200 mm ⁴ and not more than 6500 mm ⁴ , more preferably not less than 2400 mm ⁴ and not more than 5200 mm ⁴ . The lower limit of DW ³ (B) is preferably at least 1200 mm ⁴ , more preferably at least 2400 mm ⁴ . The upper limit of DW ³ (B) is preferably at most 6500 mm ⁴ , more preferably at most 5200 mm ⁴ . The values indicated by DW ³ (A) and DW ³ (B) represent values corresponding to the second moment of section at position A and position B when the neck 4 has a substantially rectangular cross section and a load is applied in the width direction, And it is related to the ease of deflection of the neck 4 in the width direction.

When DW ³ (B) is less than 1200 mm ⁴ , deflection in the width direction becomes excessive, and when it exceeds 6500 mm ⁴ , sufficient amount of deflection in the width direction cannot be obtained. By setting DW ³ (B) to 1200 mm ⁴ to 6500 mm ⁴ , sufficient flexure of the neck 4 in the width direction can be obtained without becoming excessive.

The value represented by DW ³ (A)/DW ³ (B) is preferably from 0.01 to 0.20, more preferably from 0.03 to 0.06. The lower limit of the value represented by DW ³ (A)/DW ³ (B) is preferably at least 0.01, more preferably at least 0.03. The upper limit of the value represented by DW ³ (A)/DW ³ (B) is preferably at most 0.20, more preferably at most 0.06. In order to make DW ³ (A)/DW ³ (B) the above value, DW ³ (A) is preferably 80 mm ⁴ or more and 350 mm ⁴ or less, more preferably 80 mm ⁴ or more and 260 mm ⁴ or less. The lower limit of DW ³ (A) is preferably 80 mm ⁴ or more. The upper limit of DW ³ (A) is preferably at most 350 mm ⁴ , more preferably at most 260 mm ⁴ . When the value represented by DW ³ (A)/DW ³ (B) is less than 0.01, the deflection in the width direction of the front end of the neck 4 becomes large, and the deflection in the width direction of the entire grip portion 5 cannot be achieved. . Alternatively, the rear end of the neck 4 is too thick to be linked with the grip part 5, and only the neck 4 is flexed. When the value represented by DW ³ (A)/DW ³ (B) exceeds 0.20, sufficient deflection in the width direction cannot be realized at the front end of the neck 4 . Alternatively, the rear end of the neck 4 is thinned, and only the entire neck 4 is flexed excessively without interlocking with the grip 5 . By setting the value represented by DW ³ (A)/DW ³ (B) to 0.01 or more and 0.20 or less, the bending in the width direction of the entire grip portion 5 can be realized.

As shown in Figures 3 and 4, if the position 10 mm from position B toward the front end is defined as position H, the length of the neck 4 at position H in the width direction is preferably 3.0 mm or more and 4.5 mm the following. The length in the thickness direction of the neck portion 4 at the position H is preferably not less than 5.0 mm and not more than 6.5 mm. D/W(H), which represents the ratio of the length in the thickness direction to the length in the width direction of the neck portion 4 at the position H, is preferably 1.3 or more and 1.7 or less. If the value represented by W×D ³ at the position H of the neck 4 is WD ³ (H) mm ⁴ , and the value represented by D×W ³ is DW ³ (H) mm ⁴ , then WD ³ (H) Preferably it is 350 mm ⁴ or more and 1300 mm ⁴ or less, More preferably, it is 500 mm ⁴ or more and 1000 mm ⁴ or less. The lower limit of WD ³ (H) is preferably at least 350 mm ⁴ , more preferably at least 500 mm ⁴ . The upper limit of WD ³ (H) is preferably at most 1300 mm ⁴ , more preferably at most 1000 mm ⁴ . DW ³ (H) is preferably from 130 mm ⁴ to 600 mm ⁴ , more preferably from 200 mm ⁴ to 500 mm ⁴ . The lower limit of DW ³ (H) is preferably at least 130 mm ⁴ , more preferably at least 200 mm ⁴ . The upper limit of DW ³ (H) is preferably at most 600 mm ⁴ , more preferably at most 500 mm ⁴ .

Assuming that the position 20 mm from position B toward the front end is position G, the length of the neck 4 at position G in the width direction is preferably not less than 3.0 mm and not more than 4.5 mm. The length in the thickness direction of the neck portion 4 at the position G is preferably not less than 4.0 mm and not more than 5.5 mm. D/W(G), which represents the ratio of the length in the thickness direction to the length in the width direction of the neck portion 4 at the position G, is preferably 1.1 or more and 1.5 or less. If the value represented by W×D ³ at the position G of the neck 4 is WD ³ (G) mm ⁴ , and the value represented by D×W ³ is DW ³ (G) mm ⁴ , then WD ³ (G) Preferably it is 200 mm ⁴ or more and 750 mm ⁴ or less, More preferably, it is 300 mm ⁴ or more and 600 mm ⁴ or less. The lower limit of WD ³ (G) is preferably at least 200 mm ⁴ , more preferably at least 300 mm ⁴ . The upper limit of WD ³ (G) is preferably at most 750 mm ⁴ , more preferably at most 600 mm ⁴ . DW ³ (G) is preferably from 100 mm ⁴ to 500 mm ⁴ , more preferably from 150 mm ⁴ to 400 mm ⁴ . The lower limit of DW ³ (G) is preferably at least 100 mm ⁴ , more preferably at least 150 mm ⁴ . The upper limit of DW ³ (G) is preferably at most 500 mm ⁴ , more preferably at most 400 mm ⁴ .

Assuming that the position 30 mm from the position B toward the front end is the position F, the length in the width direction of the neck 4 at the position F is preferably not less than 3.0 mm and not more than 4.5 mm. The length in the thickness direction of the neck portion 4 at the position F is preferably not less than 3.5 mm and not more than 4.5 mm. D/W(F), which represents the ratio of the length in the thickness direction to the length in the width direction of the neck portion 4 at the position F, is preferably 0.90 or more and 1.3 or less. If the value represented by W×D ³ at the position F of the neck 4 is WD ³ (F) mm ⁴ , and the value represented by D×W ³ is DW ³ (F) mm ⁴ , then WD ³ (F) Preferably, it is 100 mm ⁴ or more and 400 mm ⁴ or less, More preferably, it is 150 mm ⁴ or more and 300 mm ⁴ or less. The lower limit of WD ³ (F) is preferably at least 100 mm ⁴ , more preferably at least 150 mm ⁴ . The upper limit of WD ³ (F) is preferably at most 400 mm ⁴ , more preferably at most 300 mm ⁴ . DW ³ (F) is preferably 90 mm ⁴ or more and 400 mm ⁴ or less, more preferably 130 mm ⁴ or more and 300 mm ⁴ or less. The lower limit of DW ³ (F) is preferably at least 90 mm ⁴ , more preferably at least 130 mm ⁴ . The upper limit of DW ³ (F) is preferably at most 400 mm ⁴ , more preferably at most 300 mm ⁴ .

The grip portion 5 is preferably at any position, in a continuous area of at least 20% of the length of the grip portion 5 in the long axis direction, the length in the thickness direction and the length in the width direction are both 4.5 mm or more, 8.0 mm or less, more preferably in a continuous area of at least 50% of the length of the grip portion 5 in the long axis direction, the length in the thickness direction and the length in the width direction are both 4.5 mm to 8.0 mm. When at least one of the length in the thickness direction and the length in the width direction is less than 4.5 mm, excessive deflection occurs in the grip portion 5 . When at least one of the length in the thickness direction and the length in the width direction exceeds 8.0 mm, deflection in the grip portion 5 does not sufficiently occur. In the grip portion 5, at any position, the length in the thickness direction and the length in the width direction are both 4.5 mm or more in a region of at least 20% of the length in the long axis direction of the grip portion 5, 8.0 mm or less, the grip portion 5 can be flexed sufficiently and not excessively.

If the position of the end portion on the front end side in the long axis direction of the grip portion 5 is defined as C, from the end portion on the front end side of the grip portion 5 to the rear end side, it becomes the position in the long axis direction of the grip portion 5. The position of 50% of the length is set as D, and the length in the width direction and the length in the thickness direction of the grip portion 5 at position C are preferably 4.5 mm or more and 8.0 mm or less. Both the length in the width direction and the length in the thickness direction of the grip portion 5 at the position D are preferably not less than 4.5 mm and not more than 8.0 mm.

Let the value represented by W×D ³ at position C of the grip 5 be WD ³ (C) mm ⁴ , and the value represented by W×D ³ at position D be WD ³ (D) mm ⁴ , the WD ³ (C) is preferably not less than 410 mm ⁴ and not more than 4000 mm ⁴ , more preferably not less than 600 mm ⁴ and not more than 1800 mm ⁴ . The lower limit of WD ³ (C) is preferably at least 410 mm ⁴ , more preferably at least 600 mm ⁴ . The upper limit of WD ³ (C) is preferably at most 4000 mm ⁴ , more preferably at most 1800 mm ⁴ . The values indicated by WD ³ (C) and WD ³ (D) represent values corresponding to the second moment of section at position C and position D when the grip portion 5 has a substantially rectangular cross section and a load is applied in the thickness direction. , and is related to the ease of bending of the grip portion 5 in the thickness direction.

When WD ³ (C) is less than 410 mm ⁴ , deflection in the thickness direction becomes excessive, and when it exceeds 4000 mm ⁴ , sufficient deflection amount in the thickness direction cannot be obtained. By setting WD ³ (C) to 410 mm ⁴ or more and 4000 mm ⁴ or less, sufficient deflection can be obtained in the thickness direction of the grip portion 5 without becoming excessive.

The value represented by WD ³ (C)/WD ³ (D) is preferably from 0.35 to 2.0, more preferably from 0.50 to 1.5. The lower limit of the value represented by WD ³ (C)/WD ³ (D) is preferably at least 0.35, more preferably at least 0.50. The upper limit of the value represented by WD ³ (C)/WD ³ (D) is preferably at most 2.0, more preferably at most 1.5. In order to make WD ³ (C)/WD ³ (D) the above value, WD ³ (D) is preferably 410 mm ⁴ or more and 4000 mm ⁴ or less, more preferably 600 mm ⁴ or more and 2400 mm ⁴ or less. The lower limit of WD ³ (D) is preferably at least 410 mm ⁴ , more preferably at least 600 mm ⁴ . The upper limit of WD ³ (D) is preferably at most 4000 mm ⁴ , more preferably at most 2400 mm ⁴ . When the value represented by WD ³ (C)/WD ³ (D) is less than 0.35, the deflection in the thickness direction of the front end of the grip part 5 becomes large, and the deflection in the thickness direction of the entire grip part 5 cannot be achieved. song. Alternatively, the position D of the grip portion 5 is too thick to realize a thin grip portion 5 . When the value represented by WD ³ (C)/WD ³ (D) exceeds 2.0, a thin grip portion 5 cannot be realized. Alternatively, the deflection in the thickness direction of the front end of the grip part 5 becomes large, and the deflection in the thickness direction of the entire grip part 5 cannot be realized. By setting the value represented by WD ³ (C)/WD ³ (D) to 0.35 or more and 2.0 or less, both the deflection in the thickness direction of the grip portion 5 as a whole and the thin grip portion 5 can be achieved.

Also, if the value represented by D×W ³ at position C is DW ³ (C) mm ⁴ , and the value represented by D×W ³ at position D is DW ³ (D) mm ⁴ , then DW ³ (C) is preferably not less than 410 mm ⁴ and not more than 4000 mm ⁴ , more preferably not less than 600 mm ⁴ and not more than 1800 mm ⁴ . The lower limit of DW ³ (C) is preferably at least 410 mm ⁴ , more preferably at least 600 mm ⁴ . The upper limit of DW ³ (C) is preferably at most 4000 mm ⁴ , more preferably at most 1800 mm ⁴ . The values indicated by DW ³ (C) and DW ³ (D) represent values corresponding to the second moment of section at position C and position D when the grip portion 5 has a substantially rectangular cross section and a load is applied in the width direction. , and is related to the ease of bending of the grip portion 5 in the width direction.

When DW ³ (C) is less than 410 mm ⁴ , deflection in the width direction becomes excessive, and when it exceeds 4000 mm ⁴ , sufficient amount of deflection in the width direction cannot be obtained. By setting DW ³ (C) to 410 mm ⁴ or more and 4000 mm ⁴ or less, sufficient bending of the grip portion 5 in the width direction can be obtained without becoming excessive.

The value represented by DW ³ (C)/DW ³ (D) is preferably from 0.35 to 2.0, more preferably from 0.50 to 1.5. The lower limit of the value represented by DW ³ (C)/DW ³ (D) is preferably at least 0.35, more preferably at least 0.50. The upper limit of the value represented by DW ³ (C)/DW ³ (D) is preferably at most 2.0, more preferably at most 1.5. In order to make DW ³ (C)/DW ³ (D) the above value, DW ³ (D) is preferably 410 mm ⁴ or more and 4000 mm ⁴ or less, more preferably 600 mm ⁴ or more and 2400 mm ⁴ or less. The lower limit of DW ³ (D) is preferably at least 410 mm ⁴ , more preferably at least 600 mm ⁴ . The upper limit of DW ³ (D) is preferably at most 4000 mm ⁴ , more preferably at most 2400 mm ⁴ . When the value represented by DW ³ (C)/DW ³ (D) is less than 0.35, the flexure in the width direction of the front end of the grip part 5 becomes large, and the flexure in the width direction of the entire grip part 5 cannot be achieved. song. Alternatively, the position D of the grip portion 5 is too thick to realize a thin grip portion 5 . When the value represented by DW ³ (C)/DW ³ (D) exceeds 2.0, a thin grip portion 5 cannot be realized. Alternatively, the flexure in the width direction of the front end of the grip portion 5 becomes large, and the flexure in the width direction of the entire grip portion 5 cannot be achieved. By setting the value represented by DW ³ (C)/DW ³ (D) to 0.35 or more and 2.0 or less, both bending in the width direction of the grip portion 5 as a whole and a thin grip portion 5 can be achieved.

The ratio of the widthwise length of the grip portion 5 at position C to the widthwise length of the grip portion 5 at position D is preferably 0.65 to 1.3, more preferably 0.70 to 1.2. The lower limit of the ratio is preferably at least 0.65, more preferably at least 0.70. The upper limit of the ratio is preferably at most 1.3, more preferably at most 1.2. The ratio of the thickness direction length of the grip portion 5 at position C to the thickness direction length of the grip portion 5 at position D is preferably 0.65 to 1.30, more preferably 0.70 to 1.2.

If the ratio of the length in the width direction of the grip portion 5 at position C to the length in the width direction of the grip portion 5 at position D, or the length in the thickness direction of the grip portion 5 at position C is relatively If the length ratio of the grip portion 5 in the thickness direction at position D is less than 0.65, position C will be thinner than position D, and stress will concentrate at position C, so the entire grip portion 5 cannot be flexed. Alternatively, the position D is thicker than the position C, and the entire grip portion 5 cannot be flexed. On the other hand, when the ratio of lengths in the width direction or the ratio of lengths in the thickness direction exceeds 1.30, stress concentrates at position D, and no deflection at position C occurs. The position C has a thicker shape than the position D, so that the entire grip portion 5 cannot be flexed. Therefore, by setting the ratio of the lengths in the width direction to the ratio of the lengths in the thickness direction to be 0.65 to 1.30, the grip portion 5 becomes uniform, and when a force is applied, the grip portion 5 can The entire grip portion 5 is bent by dispersing the stress.

The ratio of the widthwise length of neck 4 at position A to the widthwise length of grip 5 at position D is preferably 0.38 to 0.89, more preferably 0.41 to 0.54. The lower limit of the ratio is preferably at least 0.38, more preferably at least 0.41. The upper limit of the ratio is preferably at most 0.89, more preferably at most 0.54. The ratio of the thickness direction length of neck 4 at position A to the thickness direction length of grip portion 5 at position D is preferably 0.38 to 0.89, more preferably 0.54 to 0.70. The lower limit of the ratio is preferably at least 0.38, more preferably at least 0.54. The upper limit of the ratio is preferably at most 0.89, more preferably at most 0.70.

The value represented by WD ³ (A)/WD ³ (D) is preferably not less than 0.10 and not more than 0.20. The value represented by DW ³ (A)/DW ³ (D) is preferably not less than 0.05 and not more than 0.20.

As shown in FIGS. 3 and 4 , at least one of the length in the thickness direction and the length in the width direction of the neck 4 is longer than the length in the thickness direction between the position C and the position D of the grip portion 5 or The position where the length in the width direction is large. Among these positions, the position E which is the most on the front end side is located closer to the front end side than the position B by an amount of 3 mm or more. The position E of the present embodiment is located closer to the front end than the position B by 4.0 mm. Since the grip part 5 is thinner than the rear end side of the neck part 4, stress is easily generated on the side of the grip part 5, and flexure in the grip part 5 can be realized. Since the region thicker than the thickest part in the region CD of the grip portion 5 is located on the front end side by 3 mm or more from the position B, stress is likely to be generated in the grip portion 5 .

From the end on the front end side of the grip portion 5 to the rear end side, as shown in FIG. 1 , the length in the thickness direction of the outline (outline) of the grip region 5R including the soft portion 75 in side view is denoted as De , as shown in Figure 3, the length in the thickness direction of the grip portion 5 when viewed from the side is set as Dh, then the value represented by Dh/De is preferably equal to the length in the long axis direction of the grip portion 5 It is 0.75 or less in at least 20% or more of the continuous area, more preferably 0.75 or less in at least 50% or more of the length of the grip portion 5 in the long axis direction, and more preferably 0.70 or less. The length Dh in the continuous region is preferably not less than 5.5 mm and not more than 7.5 mm at the maximum.

In the continuous region of at least 20% or more of the length in the long axis direction of the grip part 5, the value represented by Dh/De in the hard part 60 is set to 0.75 or less, by reducing the thickness direction of the grip region 5R The proportion of the hard part 60 ensures the thickness that is easy to hold as the toothbrush 1, and at the same time, it is easy to generate a force that bends the grip part 5 in the thickness direction.

If as shown in FIG. 2, the length on the width direction of the contour of the grip region 5R including the soft portion 75 when viewed from the front is set as We, as shown in FIG. 4, the length on the width direction of the grip portion 5 when viewed from the front is The length of Wh is set to Wh, then the value represented by Wh/We is preferably 0.75 or less in the continuous region of at least 20% of the length in the long axis direction of the grip part 5, and is more preferably less than 0.75 in the grip part 5 0.75 or less, more preferably 0.70 or less in the continuous region of at least 50% or more of the length in the major axis direction of the . The length Wh in the continuous region is preferably not less than 5.5 mm and not more than 7.5 mm at the maximum.

In the continuous region of at least 20% or more of the length in the long axis direction of the grip part 5, the value represented by Wh/We in the hard part 60 is set to 0.75 or less, by reducing the width of the grip region 5R in the width direction The proportion of the hard part 60 ensures the thickness that is easy to hold as the toothbrush 1, and at the same time, it is easy to generate a force that bends the grip part 5 in the width direction.

As described above, in the toothbrush 1 of this embodiment, depending on the direction in which the load is applied, the side closer to the front end than the grip portion 5 has a large movable area in the width direction and the thickness direction from the grip portion 5. The deflection is moderate, and the head 3 is fully twisted in the rotation direction centered on the axis extending in the long axis direction, so the adaptability and clearance to the teeth to be cleaned can be improved without depending on the brushing method and technique. cleanability.

[Example] (Example 1 to Example 8, Comparative Example 1 to Comparative Example 5) In this example, samples of the toothbrushes of Examples 1 to 8 and Comparative Examples 1 to 5 were prepared according to the specifications shown in the following [Table 1]. Each part of the toothbrush of each example was set to the dimension shown in Table 1. The hard resin of the brush body uses PP resin, and the soft resin uses thermoplastic elastomer (Thermoplastic Elastomer, TPE). In [Table 1], as an example, the length in the width direction at position A is described as "width (A)", and the length in the thickness direction at position A is described as "thickness (A)".

[Evaluation method] Regarding "suitability to teeth or gums", by [suitability to teeth or gums based on the scrub method], [fitness to teeth or gums based on the method of Phonest] and [ Suitability to teeth or gums based on the circle/Pap method] was evaluated. In this evaluation, a three-row compact toothbrush with ST hairs transplanted by the flat wire method was used. The hair bundle diameters were all set to 1.8 mm. The hair bundles were arranged in three rows in the width direction, and in seven rows in the major axis direction. For all the hair transplantation holes, ST hairs were transplanted in such a way that the hair length became 12 mm. The thickness of the head is set to 3.0 mm.

[evaluation criteria] (1) Adaptability to teeth or gums based on scrubbing Evaluation was carried out by sensory test using a panel of 10 experts. 1 g of a commercially available dentifrice was placed on the toothbrush shown in each Example and Comparative Example and brushed for 3 minutes. The suitability to teeth or gums at this time was evaluated according to the following evaluation criteria. The average score of the 10 panelists is 4.5 or more and 5.0 or less as "☆ (star mark); Special Good", and the average score as 4.0 or more and less than 4.5 "◎ (double circle mark; Very Good)", set the average score above 3.5 and less than 4.0 as "○ circle mark (circle mark); Good (Good)" , set the average score of less than 3.5 as "× (cross mark); not good (Bad)", and judge the toothbrush whose suitability to teeth or gums is regarded as ☆, ◎ or ○ A toothbrush that achieves a good fit on the teeth or gums when brushing. "Evaluation Criteria" 5 points: "Fitness to teeth or gums" is felt very much. 4 points: "Fitness to teeth or gums" is quite felt. 3 points: "Fitness to teeth or gums" is felt. 2 points: "Fitness to teeth or gums" is slightly felt. 1 point: "Fitness to teeth or gums" is not felt at all.

(2) Suitability to teeth or gums based on the Fountain method Evaluation was carried out by sensory test using a panel of 10 experts. 1 g of a commercially available dentifrice was placed on the toothbrush shown in each Example and Comparative Example and brushed for 3 minutes. The suitability to teeth or gums at this time was evaluated according to the following evaluation criteria. The average score of 10 expert groups is 4.5 or more and 5.0 or less as "☆", the average score of 4.0 or more and less than 4.5 is "◎", and the average score is 3.5 or more and less than 4.0 Set it as "○", set the average score of less than 3.5 as "×", and judge the toothbrush with ☆, ◎, or ○ for the toothbrush's adaptability to the teeth or gums to obtain good teeth or gums when brushing Adaptive toothbrush. "Evaluation Criteria" 5 points: "Fitness to teeth or gums" is felt very much. 4 points: "Fitness to teeth or gums" is quite felt. 3 points: "Fitness to teeth or gums" is felt. 2 points: "Fitness to teeth or gums" is slightly felt. 1 point: "Fitness to teeth or gums" is not felt at all.

(3) Suitability to teeth or gums based on the circle method/Pap method Evaluation was carried out by sensory test using a panel of 10 experts. 1 g of a commercially available dentifrice was placed on the toothbrush shown in each Example and Comparative Example and brushed for 3 minutes. The suitability to teeth or gums at this time was evaluated according to the following evaluation criteria. The average score of 10 expert groups is 4.5 or more and 5.0 or less as "☆", the average score of 4.0 or more and less than 4.5 is "◎", and the average score is 3.5 or more and less than 4.0 Set it as "○", set the average score of less than 3.5 as "×", and judge the toothbrush with ☆, ◎, or ○ for the toothbrush's adaptability to the teeth or gums to obtain good teeth or gums when brushing Adaptive toothbrush. "Evaluation Criteria" 5 points: "Fitness to teeth or gums" is felt very much. 4 points: "Fitness to teeth or gums" is quite felt. 3 points: "Fitness to teeth or gums" is felt. 2 points: "Fitness to teeth or gums" is slightly felt. 1 point: "Fitness to teeth or gums" is not felt at all.

[Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative Example 5 Width of neck at position A (mm) 3.5 4.0 4 3 3.0 3.5 3.3 4.0 3.0 3.5 3.5 5.0 3.5 3.5 Thickness of the neck at position A (mm) 3.5 4.0 4.3 3.0 3.3 3.5 4.0 3.0 3.5 3.5 3.5 5.0 3.5 Width of neck at position B (mm) 7.1 8.5 9.5 6.0 6.5 10.0 7.0 6.5 12.5 5.0 8.0 8.0 14.0 Thickness of neck at position B (mm) 8.3 8.5 9.5 6.0 10.0 6.5 7.0 6.5 12.5 5.0 8.0 8.0 14.0 Width (A) / Width (B) 0.49 0.47 0.45 0.50 0.54 0.33 0.57 0.46 0.28 0.70 0.63 0.44 0.25 Thickness (A) / Thickness (B) 0.42 0.47 0.45 0.50 0.33 0.54 0.57 0.46 0.28 0.70 0.44 0.63 0.25 When the position of 40% of the length of the grip portion from the front end of the grip portion is fixed, and a load of 200 g is applied to the center of the hair-implanted portion, at least one of the width and the thickness is bent. ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ x Bending width in the width direction when a load of 200 g is applied (mm) 9.2 7.5 5.5 11.5 8.5 4.5 8.0 10.5 4.0 12.0 4.5 5.5 2.5 Bending width in the thickness direction when a load of 200 g is applied (mm) 9.5 7.5 5.5 11.5 4.5 8.5 8.0 10.5 4.0 12.0 5.5 4.5 2.5 The rotation angle of the head based on the force of torque 20 N·cm 45° 25° 20° 55° 30° 30° 40° 50° 15° 55° 25° 25° 10° Width of grip at position C (mm) 5.5 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 8.0 Thickness of grip part at position C (mm) 6.2 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 8.0 Width of grip at position D (mm) 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 7.0 12.0 Thickness of grip part at position D (mm) 5.4 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5 12.0 WD ³ (A) (mm ⁴ ) 150.1 256.0 341.9 81.0 125.8 141.5 256.0 81.0 150.1 150.1 214.4 437.5 150.1 WD ³ (B) (mm ⁴ ) 4059.7 5220.1 8145.1 1296.0 6500.0 2746.3 2401.0 1785.1 24414.1 625.0 4096.0 4096.0 38416.0 WD ³ (C) (mm ⁴ ) 1333.2 1296.0 1296.0 1296.0 1296.0 1296.0 1296.0 1296.0 1296.0 1296.0 1296.0 1296.0 4096.0 WD ³ (D) (mm ⁴ ) 1084.0 1164.6 1164.6 1164.6 1164.6 1164.6 1164.6 1164.6 1164.6 1164.6 1164.6 1164.6 20736.0 DW ³ (A) (mm ⁴ ) 150.1 256.0 341.9 81.0 141.5 125.8 256.0 81.0 150.1 150.1 437.5 214.4 150.1 DW ³ (B) (mm ⁴ ) 2970.7 5220.1 8145.1 1296.0 2746.3 6500.0 2401.0 1785.1 24414.1 625.0 4096.0 4096.0 38416.0 DW ³ (C) (mm ⁴ ) 1057.6 1296.0 1296.0 1296.0 1296.0 1296.0 1296.0 1296.0 1296.0 1296.0 1296.0 1296.0 4096.0 DW ³ (D) (mm ⁴ ) 1841.9 1886.5 1886.5 1886.5 1886.5 1886.5 1886.5 1886.5 1886.5 1886.5 1886.5 1886.5 20736.0 ^WD3 (A)/ ^WD3 (B) 0.04 0.05 0.04 0.06 0.02 0.05 0.11 0.05 0.01 0.24 0.05 0.11 0.00 DW3( ^A )/ ^DW3 (B) 0.05 0.05 0.04 0.06 0.05 0.02 0.11 0.05 0.01 0.24 0.11 0.05 0.00 ^WD3 (C)/ ^WD3 (D) 1.23 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 1.11 0.20 DW ³ (C)/DW ³ (D) 0.57 0.69 0.69 0.69 0.69 0.69 0.69 0.69 0.69 0.69 0.69 0.69 0.20 Width (C) / Width (D) 0.79 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.86 0.67 Thickness (C) / Thickness (D) 1.16 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 1.09 0.67 ^WD3 (A)/ ^WD3 (D) 0.14 0.22 0.29 0.07 0.11 0.12 0.22 0.07 0.13 0.13 0.18 0.38 0.01 DW ³ (A)/DW ³ (D) 0.08 0.14 0.18 0.04 0.08 0.07 0.14 0.04 0.08 0.08 0.23 0.11 0.01 Width (A) / Width (D) 0.50 0.57 0.61 0.43 0.50 0.47 0.57 0.43 0.50 0.50 0.71 0.50 0.29 Thickness (A) / Thickness (D) 0.65 0.73 0.78 0.55 0.60 0.64 0.73 0.55 0.64 0.64 0.64 0.91 0.29 Compatibility to the cleaning part during the scrubbing method ☆ ◎ ○ ○ ○ ☆ ◎ ◎ ○ ○ ○ x x Suitability to the dissection site during the Fountain method ☆ ◎ ○ ○ ☆ ○ ◎ ◎ ○ ○ x ○ x Adaptability to the dissection site during the circle method/Pap method ☆ ○ ○ ○ ◎ ◎ ☆ ☆ x x ○ ○ x

As shown in [Table 1], the thickness and width of the neck at position A of the samples of Examples 1 to 8 are both 3.0 mm or more and 4.3 mm or less, width (A)/width (B) and thickness ( A)/thickness (B) is 0.30 or more and 0.60 or less, and the bending in the width direction of the brush body measured by the method (α) above and the thickness direction of the brush body measured by the method (β) above At least one of the bends is based on the grip part as the starting point, and the samples of the above-mentioned embodiments 1 to 8 are found in [adaptability to teeth or gums based on the scrubbing method], [based on Good evaluation was obtained in both the suitability to teeth or gums based on the Founese method] and the [fitness to teeth or gums based on the circle method/Pap method].

In the samples of Examples 1 to 8, the bending length when a load of 200 g was applied was 6.0 mm or more and 11.0 mm or less when a load was applied in the width direction and when a load was applied in the thickness direction. The samples of Example 1, Example 7, and Example 8 in which the rotation angle of the head by the force of torque 20 N·cm was 30° to 50° were particularly good evaluations.

In the samples of Examples 1 to 8, the bending length when a load of 200 g is applied is 6.0 mm or more and 11.0 mm or less when a load is applied in the width direction, and the head is based on a force of torque 20 N·cm The sample of embodiment 5 whose rotation angle is more than 30 ° and less than 50 ° is in [adaptability to teeth or gums based on the Fangesh method] and [adaptability to teeth or gums based on the circle method/Pap method]. Adaptability] received particularly good ratings.

In the samples of Examples 1 to 8, the bending length when a load of 200 g is applied is 6.0 mm or more and 11.0 mm or less when a load is applied in the thickness direction, and the head is based on a torque of 20 N·cm The samples of Example 6 whose rotation angle is more than 30° and less than 50° are in [adaptability to teeth or gums based on scrubbing method] and [adaptation to teeth or gums based on circle method/Pap method] Sex] received particularly good reviews.

On the other hand, although the thickness and width of the neck at position A are both 3.0 mm to 4.3 mm, width (A)/width (B) and thickness (A)/thickness (B) are 0.30 or more, In the samples of Comparative Examples 1 to 2 out of the range of 0.60 or less, favorable evaluations could not be obtained in [Adaptation to teeth or gums by the circle method/Pap method]. In addition, in the sample of Comparative Example 5, although the thickness and width of the neck at the position A were both 3.0 mm or more and 4.3 mm or less, the width (A)/width (B) and thickness (A)/thickness (B) were 0.30 Outside the range of 0.60 or more, when a load of 200 g is applied in the width direction and a load of 200 g is applied in the thickness direction, no bending occurs starting from the grip part, as described above The samples of Comparative Example 5 were tested in [adaptability to teeth or gums based on scrubbing method], [adaptability to teeth or gums based on Fangesh method] and [adaptation to teeth based on circle method/Pap method]. or gingival fit] did not get good ratings.

In addition, in the sample of Comparative Example 3 in which the width of the neck at position A was outside the range of 3.0 mm to 4.3 mm, and the width (A)/width (B) was outside the range of 0.30 to 0.60, Could not get a good rating for [Fitness to teeth or gums based on the Founish method]. In the sample of Comparative Example 4 in which the thickness of the neck at position A was outside the range of 3.0 mm to 4.3 mm and the thickness (A)/thickness (B) was outside the range of 0.30 to 0.60, the [Fitness to teeth or gums based on the circle method/Pap method] could not get a good evaluation.

As mentioned above, although the preferred embodiment of this invention was described with reference to the accompanying drawings, it goes without saying that this invention is not limited to the said example. The various shapes, combinations, and the like of the constituent members shown in the above examples are examples, and various changes can be made based on design requirements and the like within a range that does not depart from the spirit of the present invention. [industrial availability]

The present invention is applicable to toothbrushes.

1: Toothbrush 2: brush body 3: head 3a: Flocking surface 3R: header area 4: Neck 4R: neck region 5: Grip 5A: Design Area 5B, 5C: protrusion 5R: Grip area 6: Planting pores 40: Hair planting department 51A, 51B: vertices 60: hard part 70, 75: soft part 100: fixture 102: heavy objects A, B, C, D, E, F, G, H, P1, S: position De, Dh, We, Wh: Length F1: the first curve area F2: second curve area F3: The third curve area F4: The fourth curve area F5: fifth curve area F6: Sixth curve area F7: seventh curve area F8: eighth curve area F9: ninth curve area F10: Tenth curve area F11: Eleventh curve area F12: Twelfth curve area F13: Thirteenth curve area F14: Fourteenth curve area F15: fifteenth curve area H0: base height/height H1, H2: Height L1: the first straight line area L2: Second straight line area L3: the third straight line area

FIG. 1 is a diagram showing an embodiment of the present invention, and is a side view showing the structure of a toothbrush 1 . Fig. 2 is a front view of the toothbrush 1 seen from the hair-implanted surface 3a side. FIG. 3 is a side view showing the structure of the hard portion 60 . Fig. 4 is a front view of the hard part 60 viewed from the flocking surface 3a side.

3: head

3a: Flocking surface

3R: header area

4: Neck

4R: neck region

5: Grip

5B, 5C: protrusion

5R: Grip area

60: hard part

A, B, C, D, E, F, G, H: position

Dh: Length

F1: the first curve area

F6: Sixth curve area

L1: the first straight line area

Claims (9)

A toothbrush, characterized in that it has: a hair transplant section, including a plurality of hair bundles; and The brush body extends in the direction of the major axis, The brush body has a hard portion made of hard resin, The hard portion has: The head is located on the front end side in the direction of the long axis, and the hair-planting part is provided on the hair-planting surface; a grip part located on the rear end side of the head in the direction of the long axis; and a neck, located between the head and the grip, Assuming that the position of the end portion on the front end side in the direction of the long axis of the neck is A, Assuming that the position of the end portion on the rear end side in the direction of the long axis of the neck portion is B, When the direction perpendicular to the flocking surface is defined as the thickness direction, and the direction parallel to the flocking surface and perpendicular to the thickness direction is defined as the width direction, Both the length in the thickness direction and the length in the width direction of the neck at the position A are not less than 3.0 mm and not more than 4.3 mm, The ratio of the length in the width direction of the neck at the position A to the length in the width direction of the neck at the position B is not less than 0.30 and not more than 0.60, The ratio of the length of the neck in the thickness direction at the position A to the length of the neck in the thickness direction at the position B is not less than 0.30 and not more than 0.60, In the bending of the brush body in the width direction measured by the following method (α), and the bending of the brush body in the thickness direction measured by the following method (β) At least one of them is bent starting from the grip part, Method (α): Divide 40 to be the length of the grip part in the direction of the major axis from the end of the grip part on the front end side in the direction of the long axis to the rear end side. The position of % is fixed, and the height of the front end of the brush body in this state is taken as the reference height. In the fixed state, all the hair-planting parts in the head are further adjusted in the width direction. A load of 200 g is applied to the central position in the long axis direction, and the starting position of the bending after 10 seconds is compared with the displacement of the front end of the brush body in the width direction relative to the reference height (in mm) Measured as the bending length, Method (β): Divide 40, which is the length of the grip part in the direction of the long axis from the end of the grip part on the front end side in the direction of the long axis to the rear end side. The position of % is fixed, and the height of the front end of the brush body in this state is taken as the reference height. A load of 200 g is applied to the central position in the long axis direction, and the displacement (in mm) in the thickness direction between the starting position of bending and the front end of the brush body relative to the reference height after 10 seconds is defined as The bending length was measured. The toothbrush as claimed in item 1, wherein, Both the bending length in the width direction and the bending length in the thickness direction are not less than 6.0 mm and not more than 11.0 mm. The toothbrush as described in claim 1 or claim 2, wherein, A rotation angle of the head when the head is rotated about an axis extending in the long-axis direction with a torque of 20 N·cm is 30° or more and 50° or less. The toothbrush according to claim 1 or claim 2, wherein, if the length in the thickness direction of the neck is set to D mm, the length in the width direction is set to W mm, the Set the value represented by W×D ³ at position A to WD ³ (A) mm ⁴ , set the value represented by W×D ³ at position B to WD ³ (B) mm ⁴ , set the The value represented by D×W ³ at position A is set to DW ³ (A) mm ⁴ , and the value represented by D×W ³ at position B is set to DW ³ (B) mm ⁴ , then WD ³ (B) is 1200 mm ⁴ or more and 6500 mm ⁴ or less, the value expressed by WD ³ (A)/WD ³ (B) is 0.01 or more and 0.20 or less, and DW ³ (B) is 1200 mm ⁴ or more and 6500 mm ⁴ Hereinafter, the value represented by DW ³ (A)/DW ³ (B) is not less than 0.01 and not more than 0.20. The toothbrush as described in claim 1 or claim 2, wherein, In the continuous area of at least 20% of the length of the grip portion in the direction of the major axis of the grip portion, the length in the thickness direction and the length in the width direction are both 4.5 mm or more, 8.0 mm or less. The toothbrush according to claim 1, wherein, assuming that the position of the end portion on the front end side in the longitudinal axis direction of the grip portion is C, the distance from the front end side of the grip portion The end portion is toward the rear end side, and the position that becomes 50% of the length of the grip portion in the long axis direction is set to D, and the length of the grip portion in the thickness direction is set to D mm, set the length in the width direction as W mm, set the value represented by W×D ³ at the position C as WD ³ (C) mm ⁴ , set the W×D at the position D The value represented by ³ is set as WD ³ (D) mm ⁴ , the value represented by D×W ³ at the position C is set as DW ³ (C) mm ⁴ , and the D×W at the position D is The value represented by ³ is set to DW ³ (D) mm ⁴ , then WD ³ (C) is 410 mm ⁴ or more and 4000 mm ⁴ or less, and the value represented by WD ³ (C)/WD ³ (D) is 0.35 or more , 2.0 or less, DW ³ (C) is 410 mm ⁴ or more and 4000 mm ⁴ or less, and the value represented by DW ³ (C)/DW ³ (D) is 0.35 or more and 2.0 or less. The toothbrush as claimed in item 6, wherein, The ratio of the length in the width direction of the grip portion at the position C to the length in the width direction of the grip portion at the position D is not less than 0.65 and not more than 1.30, A ratio of the length of the grip portion at the position C in the thickness direction to the length of the grip portion at the position D in the thickness direction is not less than 0.65 and not more than 1.30. The toothbrush as described in claim 6 or claim 7, wherein, Both the length in the thickness direction and the length in the width direction of the neck are constant or gradually increase in diameter from the front end side to the rear end side, The neck portion has at least one of a length in the thickness direction and a length in the width direction that is larger than that in the thickness direction between the position C and the position D of the grip portion. the position of the length or the length in the width direction is large, Among the positions, a position E that is closest to the front end side is located closer to the front end side than the position B by an amount of 3 mm or more. The toothbrush as described in claim 1 or claim 2, wherein, At least a part of the grip part is covered with a soft part made of soft resin, In a continuous region of at least 20% or more of the length of the grip portion in the long axis direction from the end portion on the front end side of the grip portion to the rear end side, If the length in the thickness direction including the soft part when viewing the grip part in a side view in the width direction is denoted as De, Let the length in the thickness direction of the grip portion in the side view be Dh, Let the length in the width direction including the soft part when viewing the grip part in the thickness direction be We, Let the length in the width direction of the grip portion in the front view be Wh, Then the value represented by Dh/De is below 0.75, The value represented by Wh/We is 0.75 or less.

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