TW202228549A - toothbrush - Google Patents

Abstract

The purpose of the present invention is to provide a toothbrush that can deform over a broad range rather than locally while maintaining a stabilized grip feel. The present invention has a head part that is positioned toward the distal-end side in the long-axis direction and that has a bristle implantation surface, a gripping part that is disposed farther toward the rear end than the head part, and a neck part that is disposed between the head part and the gripping part. The neck part and the gripping part each have a hard section that is formed from a hard resin, and a soft section that is formed from a soft resin and that covers at least part of the hard section. In the neck part, the entire circumference of the hard section, in an area that spans to the position of the boundary with the gripping part and that is at least 70% of the long-axis-direction length of the neck part, is covered by the soft section. In a cross-section orthogonal to the long-axis direction, the value represented by S2/S1 is 4.5-6.0 (inclusive), where A is the position of an end section of the neck part on the long-axis-direction distal-end side of the soft section, S1 is the cross-sectional area of the soft section at the position A, C is the position of the boundary in the long-axis direction, and S2 is the cross-sectional area of the soft section at the position C.

Description

toothbrush

The present invention relates to a toothbrush. The present application claims priority based on Japanese Patent Application No. 2020-208534 for which it applied in Japan on December 16, 2020, and the content is incorporated herein by reference.

When brushing teeth, it is generally recommended to brush with light force and carefully and gently brush each tooth. Therefore, it is preferable that the handle body has moderate elasticity (softness). On the other hand, if the grip portion of the toothbrush is too soft, the force cannot be transmitted well, and the feeling of use is poor, so it is required to be firmly gripped.

Therefore, measures for imparting elasticity such as flexible use of a highly elastic hard resin and thinning of the neck are adopted. In addition, the grip is designed to be easily partially flexed by combining an elastic body and a hard resin on the neck or the grip.

For example, Patent Document 1 discloses a toothbrush of a specification in which the brushing pressure is reduced by combining an elastic body in the boundary section between the neck and the grip. Patent Document 2 discloses a toothbrush of a specification in which deformability is imparted to two places by having a spherical structure at the boundary between the head and the neck and a accordion structure at the neck. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2000-4944 [Patent Document 2] US Patent Application Publication No. 2013/0340189

[The problem to be solved by the invention]

However, when deformation occurs at one or two places from the neck to the grip portion, the force applied to the grip portion is locally attenuated, so there is a sense of conflict during brushing, and the usability is insufficient. In addition, since the stress is locally concentrated, there are problems such as insufficient strength such as fracture and plastic deformation due to long-term use.

The present invention has been made in consideration of the above-mentioned aspects, and an object of the present invention is to provide a toothbrush capable of being deformed not locally but in a wide range while maintaining a stable grip. [Means of Solving Problems]

According to a first aspect of the present invention, there is provided a toothbrush characterized by comprising: a head portion located on the front end side in the long-axis direction and having a hair-implanted surface; and a grip portion disposed on the rear end side of the head portion ; and a neck portion, disposed between the head portion and the grip portion, the neck portion and the grip portion respectively have: a hard portion, formed of a hard resin; and a soft portion, formed of a soft resin and Covering at least a part of the hard portion, the neck portion is at least 70% of the length of the neck portion in the long axis direction, and is a boundary position with the grip portion, the hard portion The entire circumference of the soft part is covered by the soft part, and in the cross section orthogonal to the long axis direction, if the position of the end part on the front end side in the long axis direction of the soft part in the neck part is Let A be the cross-sectional area of the soft portion at the position A, S1, the boundary position in the long axis direction, C, and the soft portion at the position C to be Assuming that the cross-sectional area is S2, the value represented by S2/S1 is 4.5 or more and 6.0 or less.

Moreover, in the toothbrush of one aspect of the present invention, if the total cross-sectional area of the neck portion perpendicular to the long axis direction at the boundary position is S3, the Assuming that the cross-sectional area of the hard portion is S4, the value represented by S3/S4 is 2.0 or more and 4.0 or less.

In addition, in the toothbrush according to one aspect of the present invention, the grip portion has a finger contact portion on the front side facing the bristles surface in a thickness direction orthogonal to the bristles surface. In the cross section, the finger contact portion has a flat shape whose length in the width direction orthogonal to the long axis direction and the thickness direction is longer than the length in the thickness direction.

In addition, in the toothbrush according to one aspect of the present invention, when viewed from the side in the width direction, the finger contact portion has a convex apex on the front side, and has The width between contour lines in the width direction of a curved surface of a concave shape having a center of curvature on the front side from the vertex toward the rear end side when viewed from the front side In the finger contact portion, the hard portion is exposed on the front side, and the soft portion sandwiches the finger contact portion from the boundary position to a position at which the finger contact portion has a maximum width. The side surfaces on both sides in the width direction of the hard part cover the hard portion until it exceeds the boundary position and becomes the position of the maximum width.

In addition, in the toothbrush according to one aspect of the present invention, the soft portion extends beyond the boundary position at least on the back side which is the opposite side to the front side in the thickness direction. the rear end side.

In addition, in the toothbrush according to one aspect of the present invention, the soft portion is arranged in order from the neck portion toward the rear end side of the grip portion to cover the hard portion over the entire circumference. The first region, the second region where the soft portion covers the hard portion only on the side and the back side, and the third region where the soft portion covers the hard portion only on the back side.

In addition, in the toothbrush according to one aspect of the present invention, the grip portion at the position of the maximum width has, in the cross section, a first surface portion facing the front surface. side and extending in the width direction; and a second surface portion, with the intersections with the first surface as ridgelines, respectively, and toward the thickness from the intersections to the outside in the width direction, respectively The rear side is inclined in the direction opposite to the front side, and the distance between the ridge lines in the width direction gradually decreases toward the rear end side from the position where the maximum width becomes the width, and then gradually expands to the The thickness of the grip portion reaches the maximum position.

Further, in the toothbrush according to one aspect of the present invention, among the intersecting angles of a pair of the second surface portions, the intersecting angle representing the range occupied by the hard portion in the cross section is selected from The position where the distance between the ridge lines in the width direction becomes the smallest becomes gradually smaller toward the position where the thickness of the grip portion becomes the largest.

Moreover, in the toothbrush according to one aspect of the present invention, in the cross section at the position A, the hard portion is located in a thickness direction orthogonal to the bristles surface relative to the hard portion. The thickness of the soft portion on the back side opposite to the hair-implanted surface is set to A1, and the thickness of the soft portion is set to be closer to the hard portion than the hard portion and the width perpendicular to the long axis direction and the thickness direction. The thickness of the soft portion at the outer side in the direction is set to A2, and in the cross-section at the position C, if the thickness of the soft portion is located on the back side in the thickness direction relative to the hard portion, Let the thickness of the soft part be C1, and let the thickness of the soft part located on the outer side in the width direction of the hard part be C2, then (C2/A2)/(C1/A1)>2.5 Relationship.

Moreover, in the toothbrush of one aspect of the present invention, the thickness C2 is 2.7 mm or more and 4.0 mm or less, and the thickness C1 is 0.7 mm or more and 1.5 mm or less.

Moreover, in the toothbrush according to one aspect of the present invention, if the maximum thickness of the neck portion at the position A is A11, and the maximum thickness of the hard portion is A12, The maximum width of the neck at the position A is A21, the maximum width of the hard portion is A22, the maximum thickness of the neck at the position C is C11, and the The maximum thickness of the hard portion is set to C12, the maximum width of the neck portion at the position C is set to C21, and the maximum width of the hard portion is set to C22, then (C12/C11)/(A12/ The value represented by A11) is 0.95 or more and 1.15 or less, and the value represented by (C22/C21)/(A22/A21) is 0.70 or more and 0.90 or less. [Effect of invention]

In the present invention, it is possible to provide a toothbrush that can be deformed not locally but in a wide range while maintaining a stable grip.

Hereinafter, embodiments of the toothbrush of the present invention will be described with reference to FIGS. 1 to 8 . In addition, the following embodiment shows one aspect of this invention, Comprising: It does not limit this invention, It can change arbitrarily within the range of the technical idea of this invention. In addition, in the following drawings, in order to facilitate understanding of each structure, the scale, the number, etc. of the actual structure and each structure are different.

In addition, in the following description, the side (side facing the hair-implantation surface) of the head 3 on which the hair-implantation surface 3a described later is provided is the front side of the toothbrush 1, and the hair-implantation surface 3a of the head part 3 faces. The opposite side to the opposite side is the back side of the toothbrush 1 . In addition, let the direction in which the brush body 2 extends be the long-axis direction, let the direction parallel to the bristle-implantation surface 3a and orthogonal to the long-axis direction be the width direction of the toothbrush 1, and let the direction orthogonal to the bristle-implanting surface 3a be the toothbrush The thickness direction of 1 will be described. In addition, it is appropriate to set the side where the head 3 is provided in the longitudinal direction (head side) as the front end side, and the side where the grip portion 5 is provided (the grip portion side) as the rear end side. illustrate.

FIG. 1 is a side view showing the structure of the toothbrush 1 . 2 : is the front view which looked at the toothbrush 1 from the hair-implantation surface 3a side. In addition, in FIG. 2, illustration of the brush 40 is abbreviate|omitted. FIG. 3 is a back view of the toothbrush 1 viewed from the back side. In FIG. 2, illustration of the brush 40 is abbreviate|omitted.

As shown in FIGS. 1 to 3 , the toothbrush 1 of the present embodiment includes a brush body 2 including a resin molded body formed in an elongated shape as a whole, and a brush 40 . As an example, the full length of the toothbrush 1 is 180 mm or more and 200 mm or less.

The brush body 2 includes: a head 3 that is located on the front end side and has a hair-implanting surface 3a; a grip part 5 that is arranged on the rear end side of the head 3; and a neck 4 that is arranged between the head 3 and the grip part between 5. The toothbrush 1 can clean the inside of an oral cavity by the brush 40 which has several bristle bundles (not shown) implanted in the hair-implantation surface 3a of the head part 3.

The brush body 2 has a hard portion 60 formed of a hard resin and a soft portion 70 formed of a soft resin, respectively. The hard portion 60 extends in the longitudinal direction. The hard part 60 forms at least a part of the head part 3 , the neck part 4 and the grip part 5 . The hard part 60 includes: a hard part 63 located on the head part 3 , a hard part 64 located on the neck part 4 , and a hard part 65 located on the grip part 5 .

The soft part 70 covers at least a part of the hard part 60 in the head part 3 , the neck part 4 , and the grip part 5 , respectively. The soft part 70 includes a soft part 73 located on the head part 3 , a soft part 74 located on the neck part 4 , and a soft part 75 located on the grip part 5 .

As an example of the hard resin, a resin having a flexural modulus of elasticity (Japanese Industrial Standards (JIS) 7171) of 1,000 MPa or more and 2,800 MPa or less is used, and preferably polypropylene (Polypropylene) is used in consideration of strength. , PP) resin, polyacetal (Polyoxymethylene, POM) resin, polybutylene terephthalate (Polybutylene Terephthalate, PBT) resin.

As a soft resin, Shore A hardness of 30 or more and 80 or less is more preferable. Examples of soft resins include elastomers (eg, 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 , in the toothbrush 1 of the present embodiment, when the brush body 2 is viewed from the side, in the outline of the front side of the brush body 2, from the rear end side of the head 3 to the grip portion 5 side : The first straight line area L1 extends straight from the hair planting surface 3a of the head 3 to the rear end side continuously; the first curved area E1 has a center of curvature on the front side and extends from the rear end of the first straight line area L1 to a convex shape The second curved region E2 has a center of curvature on the front side and extends in an arc shape from the vertex 51 to the rear end side. In addition, the toothbrush 1 has a third curved area E3 on the front side in a side view, the third curved area E3 has a center of curvature on the back side, and extends in an arc shape from the rear end of the second curved area E2 to the rear end side .

(Outline shape of the back side of the brush body) Regarding the toothbrush 1 of the present embodiment, when the brush body 2 is viewed from the side, in the outline on the back side of the brush body 2, from the rear end side of the head 3 to the grip portion 5 side, there is a second straight line area L2 , extending continuously from the back of the head 3 to the rear end side in a straight line; the fourth curved area E4 has a center of curvature on the front side, and extends in an arc shape from the rear end side of the second straight area L2 to the rear end side; The fifth curved region E5 has a center of curvature on the back side, and extends in a circular arc shape from the rear end of the fourth curved region E4 to the vertex 51A toward the rear end side; and the sixth curved region E6 has a center of curvature on the back side, And it extends in an arc shape from the vertex 51A toward the rear end side.

(Outline shape on both sides of the brush body in the width direction) As shown in FIG. 2 , regarding the toothbrush 1 of the present embodiment, when the brush body 2 is viewed from the front, the outer shapes of both sides in the width direction of the brush body 2 with respect to the center line located at the center in the width direction and extending in the longitudinal direction The contour lines are formed to be line-symmetrical. Therefore, in the following description, the outline of one side (lower side in FIG. 2 ) in the width direction will be described. In addition, the position of the center of curvature of the arcuately extending curved region is referred to as the inner side in the case of the center in the width direction with respect to the outer contour line, and the case on the opposite side from the center in the width direction is referred to as the inner side. outside.

Regarding the toothbrush 1 of the present embodiment, when the brush body 2 is viewed from the front, in the outline of the width direction of the brush body 2, there are: a third straight line area L3 from the boundary between the head 3 and the neck 4 (details (described later) to the position B extending linearly toward the rear end; the seventh curved area E7 has a center of curvature on the outside, and extends in an arc shape from the position B to the rear end; the eighth curved area E8 has a center of curvature on the inside , and extends from the rear end of the seventh curved region E7 to the rear end side in an arc shape; the ninth curved region E9 has a center of curvature on the outside, and extends from the rear end of the eighth curved region E8 to the rear end side in an arc shape ; and the tenth curved region E10, which has a center of curvature on the inner side, and extends in an arc shape from the rear end of the ninth curved region E9 to the rear end side. The neck 4 in the toothbrush 1 of this embodiment is extended with a constant width from the position J to the position B of the boundary with the head 3 mentioned later. That is, the position B is the position of the end portion on the rear end side where the width of the neck portion 4 becomes constant.

(head) The head portion 3 is a portion for brushing the inside of the oral cavity with a plurality of hair bundles, and as shown in FIG. 2 , has a shape formed in a substantially rectangular parallelepiped shape, and a corner portion has an arcuate shape. The head 3 has a substantially quadrangular flat plate-like shape in which four tops are chamfered by a curved line when viewed from the front. In the present embodiment, the boundary between the head 3 and the neck 4 is the end point of the curve forming the chamfer on the neck 4 side in the frontal shape of the head 3 , that is, the position where the bending direction of the chamfer changes.

The head 3 has a hair-implanting surface 3a on the front side. On the hair-implantation surface 3a, a plurality of planting pores 6 are arranged in a row. The shape and the pore diameter of the vegetative pores 6 are not particularly limited, but as an example, FIG. 2 shows the vegetative pores 6 which are viewed as circular and have the same diameter. Corresponding to the length of the head 3 in the width direction, a plurality of rows (two to four in FIG. 2 ) of the vegetative pores 6 are arranged at intervals in the width direction at intervals in the long axis direction. Set up multiple lines (10 lines in Figure 2). The hair bundles constituting the brush 40 are each implanted in the implantation pores 6 .

The hair bundles are planted in each planting hole 6 by bundling a plurality of bristles (filaments) and folding them in half, and sandwiching a metal anti-shedding tool (not shown) called a flat wire therebetween. And into the implanted pores 6. The shape of the head 3 is not particularly limited, but for example, the hair-implantation surface 3a on the front side and the surface on the back side are flat and parallel to each other.

The shape of the head portion 3 is not particularly limited as long as it has a shape or size that can easily brush the inside of the oral cavity. In addition, the head 3 may have a tapered shape whose thickness gradually decreases from the base end side toward the front end side, or may have a shape in which the center portion on the back side of the head portion 3 is raised and has a circular arc.

The width of the head 3 is not particularly limited, but is preferably 7 mm or more and 16 mm or less, for example. If it is more than the said lower limit, the area in which the hair bundle is implanted can be sufficiently secured, and if it is less than or equal to the said upper limit, the operability in the oral cavity can be further improved.

The length in the longitudinal direction of the head 3 is not particularly limited, but is preferably 10 mm or more and 33 mm or less, for example. When the length of the head part 3 is more than the said lower limit value, the area in which the hair bundle is implanted can be sufficiently secured, and when it is less than or equal to the said upper limit value, the operability in the oral cavity can be further improved.

The thickness of the entire area of the head 3 is not particularly limited, but is preferably 3.0 mm or more and 6.0 mm or less as an example. If the thickness of the head part 3 is equal to or more than the above lower limit value, the strength of the head part 3 can be further improved. When the thickness of the head portion 3 is equal to or less than the upper limit value, the reachability to the depths of the molars can be improved, and the operability in the oral cavity can be further improved.

As shown in FIGS. 1 and 3 , in a part of the back side of the head 3 , a part of the hard part 63 is covered with the soft part 73 . The soft portion 73 covers the entire area beyond the center from the front end side of the head 3 , and partially covers the center portion in the width direction on the rear end side from this area. The soft portion 73 has a plurality of squeegees 73A and a plurality of squeegees 73B protruding toward the back side. The scraper 73A is a V-shaped rib extending from the front end side toward the rear end side, and is arranged at intervals along the long axis direction. The scrapers 73B are linear protrusions and are arranged in a scattered manner. In addition, the shape of the said squeegee 73A and the squeegee 73B is an example, and the shape is not specifically limited. In addition, the structure in which the scraper 73A and the scraper 73B are not provided in the head 3 may be adopted.

(neck) The neck portion 4 is a portion that is arranged between the grip portion 5 and the head portion 3 and connects the grip portion 5 and the head portion 3 . The boundary between the neck portion 4 and the grip portion 5 is the position C where the seventh curved region E7 and the eighth curved region E8 intersect each other when viewed from the front. That is, it is the position where the change of the curve direction starts when the seventh curve region E7 having the center of curvature on the outside and the eighth curve region E8 having the center of curvature on the inside are connected. The distance in the long axis direction from the front end of the head 3 to the position C is preferably 65 mm or more and 85 mm or less.

Regarding the neck portion 4 , from the boundary with the head portion 3 toward the grip portion 5 to the position B, the region formed by the third straight line region L3 in the front view of FIG. 2 has a constant minimum width. Regarding the neck portion 4 , the width of the region from the position B to the position C where the outer contour line is formed by the seventh curved region E7 gradually increases from the minimum width. The minimum width of the neck portion 4 is preferably 4.5 mm or more and 6.0 mm or less from the viewpoint of usability. The maximum width of the neck portion 4 is preferably 14.0 mm or more and 15.5 mm or less from the viewpoint of usability.

Regarding the neck portion 4, from the boundary with the head portion 3 toward the grip portion 5, in the side view of FIG. The thickness of the region up to the position C formed by the first curved region E1 and the fourth curved region E4 is gradually increased from the minimum thickness. The minimum thickness of the neck portion 4 is preferably 4.5 mm or more and 6.0 mm or less from the viewpoint of usability. The maximum thickness of the neck portion 4 is preferably 9.0 mm or more and 12.5 mm or less from the viewpoint of usability.

In the neck 4, from the position A at the center of the neck 4 on the side of the head 3 in the longitudinal direction to 70% or more of the length in the longitudinal direction of the neck 4, and the length of the neck 4 is equal to or more than 70% of the length in the longitudinal direction. At the position C of the boundary position of the holding portion 5 , the entire circumference of the hard portion 64 is covered by the soft portion 74 . The position in the long-axis direction of the position A is preferably 33 mm to 45 mm from the front end of the head 3 .

If the cross-sectional area of the soft portion 74 at the position A is S1 and the cross-sectional area of the soft portion 74 at the position C is S2, the value represented by S2/S1 is preferably 4.5 or more and 6.0 or less, more preferably It is 4.8 or more and 5.7 or less, and particularly preferably 5.1 or more and 5.5 or less. Moreover, 4.5 or more are preferable, 4.8 or more are more preferable, and 5.1 or more are especially preferable. Moreover, 6.0 or less are preferable, 5.7 or less are more preferable, and 5.5 or less are especially preferable. When the value represented by S2/S1 is less than 4.5, there is a possibility that the deformation of the neck portion 4 becomes excessively large at a position close to the grip portion 5 . When the value represented by S2/S1 exceeds 6.0, there is a possibility that the deformation of the neck portion 4 becomes too large at a position close to the grip portion 5 . In addition, there is a possibility that the deformation of the neck 4 becomes too large at a position close to the head 3 . By setting the value represented by S2/S1 to be 4.5 or more and 6.0 or less, the center of deformation can be placed on the front end side of the neck 4, and the flexibility of bending can be controlled using the soft part 74 as a reinforcing material so as to follow the grip. the side of the holding part 5 to reduce the degree of deformation. In addition, the cross-sectional area S1 is preferably 8 mm ² or more and 22 mm ² or less, more preferably 10 mm ² or more and 20 mm ² or less, and still more preferably 12 mm ² or more and 18 mm ² or less. The cross-sectional area S2 is preferably 60 mm ² or more and 60 mm ² or less, more preferably 65 mm ² or more and 85 mm ² or less, and still more preferably 70 mm ² or more and 80 mm ² or less.

In addition, if the total cross-sectional area of the neck portion 4 at the position C is S3 and the cross-sectional area of the hard portion 64 is S4, the value represented by S3/S4 is preferably 2.0 or more and 4.0 or less, more preferably 2.4 or more and 3.6 or less, particularly preferably 2.7 or more and 3.3 or less. Moreover, 2.0 or more are preferable, 2.4 or more are more preferable, and 2.7 or more are especially preferable. Moreover, 4.0 or less are preferable, 3.6 or less are more preferable, and 3.3 or less are especially preferable. When the value represented by S3/S4 is less than 2.0, there is a possibility that the deformation of the neck portion 4 becomes too small at a position close to the grip portion 5 . When the value represented by S3/S4 exceeds 4.0, there is a possibility that the deformation of the neck portion 4 at a position close to the grip portion 5 becomes excessively large. In addition, the cross-sectional area S3 is preferably 100 mm ² or more and 130 mm ² or less, more preferably 105 mm ² or more and 125 mm ² or less, and still more preferably 110 mm ² or more and 120 mm ² or less. The cross-sectional area S4 is preferably 25 mm ² or more and 55 mm ² or less, more preferably 30 mm ² or more and 50 mm ² or less, and still more preferably 35 mm ² or more and 45 mm ² or less.

FIG. 4 is a cross-sectional view at position A perpendicular to the longitudinal direction of the neck 4 . FIG. 5 is a cross-sectional view orthogonal to the longitudinal direction of the neck 4 at the position C. FIG. As shown in FIG. 4 , in the cross section at the position A, the thickness of the soft part 74 located on the back side of the harder part 64 is A1, and the thickness of the soft part 74 located on the outer side in the width direction of the hard part 64 is set to be A1. The thickness of the portion 74 is A2. As shown in FIG. 5 , in the cross section at the position C, if the thickness of the soft portion 74 located on the back side of the hard portion 64 is C1, the thickness of the soft portion 74 located on the outer side in the width direction of the hard portion 64 is set to be C1. If the thickness of the soft portion 74 is C2, the value represented by (C2/A2)/(C1/A1) is preferably 2.5, more preferably more than 2.5 and less than 3.8, and still more preferably 3.0 or more and 3.6 or less , especially preferably above 3.2 and below 3.4. Moreover, it is preferable that it exceeds 2.5, it is more preferable that it is 3.0 or more, and it is especially preferable that it is 3.2 or more. Moreover, less than 3.8 is preferable, 3.6 or less is more preferable, and 3.4 or less is especially preferable. If the value represented by (C2/A2)/(C1/A1) is 3.8 or more, since the wall thickness becomes excessively thick, it may become difficult to deform in the width direction.

When the value represented by (C2/A2)/(C1/A1) is 2.5 or less, the thickness of the soft portion 74 in the width direction is thin, so it is easy to deform in the width direction. When the value represented by (C2/A2)/(C1/A1) exceeds 2.5, deformation in the short axis (width) direction is suppressed. In addition, the thickness A1 is preferably 0.7 mm or more and 1.3 mm or less, more preferably 0.8 mm or more and 1.2 mm or less, and still more preferably 0.9 mm or more and 1.1 mm or less. The thickness A2 is preferably 0.7 mm or more and 1.3 mm or less, more preferably 0.8 mm or more and 1.2 mm or less, and still more preferably 0.9 mm or more and 1.1 mm or less.

As a value represented by C1/A1, 0.9 or more and 2.0 or less are preferable, and 1.1 or more and 1.15 or less are more preferable. As a value represented by C2/A2, 2.0 or more and 5.0 or less are preferable, and 2.5 or more and 4.0 or less are more preferable. The value represented by C1-A1 is preferably 0 mm or more and 0.6 mm or less. The value represented by C2-A2 is preferably 1.8 mm or more and 3.5 mm or less.

As thickness C1, 0.7 mm or more and 1.5 mm or less are preferable. When the thickness C1 is less than 0.7 mm, the deflection in the thickness direction becomes large, and there is a possibility that the touch comfort is lowered, and the grip property is deteriorated. When the thickness C1 exceeds 1.5 mm, there is a possibility that the deformability with respect to the pressure to the back side of the head 3 may decrease. By setting the thickness C1 to be 0.7 mm or more and 1.5 mm or less, it is possible to improve the touch comfort and the grip while maintaining the deformability with respect to the pressure to the back side. In addition, the thickness C1 is preferably 0.7 mm or more and 1.7 mm or less, more preferably 0.8 mm or more and 1.5 mm or less, and still more preferably 0.9 mm or more and 1.3 mm or less.

The thickness C2 is preferably 2.5 mm or more and 4.5 mm or less, more preferably 2.7 mm or more and 4.0 mm or less, and still more preferably 3.0 mm or more and 3.8 mm or less. When the thickness C2 is less than 2.5 mm, the deflection in the width direction becomes large, and there is a possibility that the touch comfort is lowered and the grip property is deteriorated. When the thickness C2 exceeds 4.5 mm, there is a possibility that the deformability in the width direction with respect to the pressurization to the back side of the head 3 may decrease. By setting the thickness C2 to be 2.5 mm or more and 4.5 mm, it is possible to improve contact comfort and grip while maintaining the deformability in the width direction.

The minimum width of the hard portion 64 in the neck portion 4 is preferably 3.0 mm or more and 4.0 mm or less. The maximum width of the hard portion 64 in the neck portion 4 is preferably 7.0 mm or more and 8.5 mm or less.

The minimum thickness of the hard portion 64 in the neck portion 4 is preferably 3.0 mm or more and 4.0 mm or less. The maximum thickness of the hard portion 64 in the neck portion 4 is preferably 6.0 mm or more and 7.5 mm or less. As an example, the thickness of the neck 4 at a position 37 mm from the front end of the head 3 in the middle of the neck 4 is preferably 3.3 mm or more and 3.5 mm or less. As an example, the thickness of the neck portion 4 at a position 56 mm from the front end of the head portion 3 is preferably 4.2 mm or more and 4.5 mm or less. As an example, the thickness of the neck portion 4 at a position 77 mm from the front end of the head portion 3 is preferably 8.7 mm or more and 8.9 mm or less. By making the thickness of the hard part 64 in the neck part 4 into the said range, it becomes the tapered shape which is easy to bend from the center part of the neck part 4 as a whole.

As shown in FIG. 4 , the maximum thickness of the neck portion 4 at the position A is A11, the maximum thickness of the hard portion 64 is A12, the maximum width of the neck portion 4 is A21, and the maximum width of the hard portion 64 is A21. Set to A22. As shown in FIG. 5 , the maximum thickness of the neck portion 4 at the position C is C11, the maximum thickness of the hard portion 64 is C12, the maximum width of the neck portion 4 is C21, and the maximum width of the hard portion 64 is C21. Set to C22.

The value represented by (C12/C11)/(A12/A11) is preferably 0.95 or more and 1.15 or less, more preferably 0.97 or more and 1.10 or less, and particularly preferably 1.00 or more and 1.05 or less. Moreover, 0.95 or more is preferable, 0.97 or more is more preferable, and 1.00 or more is especially preferable. In addition, it is preferably 1.15 or less, more preferably 1.10 or less, and particularly preferably 1.05 or less. When the value represented by (C12/C11)/(A12/A11) is less than 0.95, the deflection becomes too large, and there is a possibility that the touch comfort is lowered and the grip property is deteriorated. When the value represented by (C12/C11)/(A12/A11) exceeds 1.15, the soft portion 74 becomes too thin, and it is difficult to bend in the width direction, which may reduce flexibility. By setting the value represented by (C12/C11)/(A12/A11) to 0.95 or more and 1.15 or less, it is possible to improve touch comfort and grip while suppressing a decrease in flexibility. The thickness A11 is preferably 4.8 mm or more and 5.8 mm or less, more preferably 5.0 mm or more and 5.6 mm or less, and still more preferably 5.2 mm or more and 5.4 mm or less. The thickness A12 is preferably 3.0 mm or more and 3.8 mm or less, more preferably 3.2 mm or more and 3.6 mm or less, and still more preferably 3.3 mm or more and 3.5 mm or less. The thickness C11 is preferably 10.8 mm or more and 12.2 mm or less, more preferably 11.0 mm or more and 12.0 mm or less, and still more preferably 11.2 mm or more and 11.8 mm or less. The thickness C12 is preferably 7.1 mm or more and 8.3 mm or less, more preferably 7.3 mm or more and 8.1 mm or less, and still more preferably 7.5 mm or more and 7.9 mm or less.

The value represented by (C22/C21)/(A22/A21) is preferably 0.70 or more and 0.90 or less, more preferably 0.74 or more and 0.86 or less, and particularly preferably 0.77 or more and 0.83 or less. Moreover, 0.7 or more is preferable, 0.74 or more is more preferable, and 0.77 or more is especially preferable. Moreover, 0.90 or less is preferable, 0.86 or less is more preferable, and 0.83 or less is especially preferable. When the value represented by (C22/C21)/(A22/A21) is less than 0.70, the deflection becomes too large, and there is a possibility that the touch comfort is lowered and the grip property is deteriorated. When the value represented by (C22/C21)/(A22/A21) exceeds 0.90, the thickness of the soft portion 74 varies little, so that it is rigid as a whole and is difficult to bend integrally, and flexibility may also decrease. By setting the value represented by (C22/C21)/(A22/A21) to be 0.70 or more and 0.90 or less, it is possible to improve touch comfort and grip performance while suppressing a decrease in flexibility. The width A21 is preferably 4.8 mm or more and 5.8 mm or less, more preferably 5.0 mm or more and 5.6 mm or less, and still more preferably 5.2 mm or more and 5.4 mm or less. The width A22 is preferably 3.0 mm or more and 3.8 mm or less, more preferably 3.2 mm or more and 3.6 mm or less, and still more preferably 3.3 mm or more and 3.5 mm or less. The width C21 is preferably 12.1 mm or more and 13.6 mm or less, more preferably 12.4 mm or more and 13.3 mm or less, and still more preferably 12.7 mm or more and 13.0 mm or less. The width C22 is preferably 5.8 mm or more and 7.3 mm or less, more preferably 6.1 mm or more and 7.0 mm or less, and still more preferably 6.4 mm or more and 6.7 mm or less.

As a value represented by A12/A11, 0.6 or more and 0.8 or less are preferable. The value represented by A22/A21 is preferably 0.6 or more and 0.8 or less. As a value represented by C12/C11, 0.6 or more and 0.9 or less are preferable. As a value represented by C22/C21, 0.4 or more and 0.6 or less are preferable.

As the amount of deformation of the neck portion 4, a weight of 200 g was stopped at the center of the width direction and the longitudinal direction of the head portion 3 at the position C fixed at the boundary between the neck portion 4 and the grip portion 5, and hung for 10 seconds. The position of the parting line at the front end of the head is deformed by 6 mm to 9 mm.

As long as the above-mentioned values are satisfied, the cross-sectional shape of the neck portion 4 is preferably a substantially quadrangular shape, a substantially polygonal shape, a perfect circle, or an ellipse.

(grip part) The grip portion 5 is a portion held by the user, and is formed in a long column shape. The grip portion 5 gradually widens (expands) from the position C of the boundary with the neck portion 4 toward the rear end side to the position D where the outline represents the maximum value of the eighth curve region E8 in front view. From the position D where the eighth curve area E8 shows the maximum value to the position F where the ninth curve area E9 shows the minimum value in front view, the width of the contour line on the rear end side gradually narrows. From the position F where the ninth curve region E9 shows the minimum value to the position G where the tenth curve region E10 shows the maximum value in front view, the width of the outer contour line on the rear end side gradually widens. The grip portion 5 of the present embodiment has the maximum width at the position G where the tenth curve region E10 shows the maximum value. The width of the contour line on the rear end side gradually narrows from the position G where the tenth curve region E10 shows the maximum value in front view to the end on the rear end side.

Regarding the grip portion 5, from the position C of the boundary with the neck portion 4 toward the rear end side in the side view of FIG. When viewed from the side, the thickness of the contour line gradually decreases. The position E is preferably 70 mm to 90 mm from the front end of the head 3 . From the position E where the second curve area E2 shows the minimum value to the position H where the third curve area E3 and the sixth curve area E6 show the maximum value in side view, the thickness of the contour line on the rear end side gradually increases . The grip portion 5 of the present embodiment has the maximum thickness at the position H. As shown in FIG. From the position H to the end on the rear end side, the thickness of the outer contour line on the rear end side gradually decreases.

The grip portion 5 has, as an example, a finger contact portion 50 on the front side with which the thumb is abutted. The finger contact portion 50 is formed in the second curved region E2 that is a concave curved surface toward the back side from the vertex 51 toward the rear end side to the position E when viewed from the side. By providing the curved surface of the concave shape in the finger contact portion 50, flexibility can be exhibited when the finger contact portion 50 is pressed toward the back side.

Since the finger contact portion 50 has the convex apex 51 and the flat shape, it can be adjusted so as not to bend excessively in the thickness direction, and moderate flexibility can be transmitted to the grip portion 5 side. In addition, by providing the convex apex 51, the thickness of the soft portion 75 on the front side can be ensured to be thick, so that it does not bend excessively in the thickness direction, and moderate flexibility can be transmitted to the grip portion 5 side, the flexibility of the neck 4 can be gradually suppressed toward the grip portion 5 .

The position D is a position where the finger contact portion 50 has the maximum width, and is preferably located on the rear end side of the vertex 51 . The position in the long-axis direction of the position D is preferably 65 mm to 85 mm from the front end of the head 3 .

FIG. 6 is a cross-sectional view of the position D where the finger contact portion 50 has the maximum width. As shown in FIG. 6 , the cross section of the grip portion 5 at the position D is a substantially hexagonal shape having a straight line on the front side. The grip portion 5 has an upper surface (first surface portion) 56 that faces the front side and extends in the width direction, and a side surface (second surface portion) 52 whose intersections with the upper surface 56 serve as ridge lines 57 , respectively. Each of the intersecting portions is inclined toward the outer side in the width direction and toward the back side. The upper surface 56 is the finger contact surface of the finger contact portion 50 .

The cross-sectional shape of the finger contact portion 50 is a flat shape in which the length in the width direction is longer than the length in the thickness direction. By making the cross-sectional shape of the finger contact portion 50 a flat shape, the finger contact portion 50 is easily deformed when a force toward the back side is applied to the finger contact portion 50 . By making the cross section of the grip portion 5 at the position D into a flat and substantially hexagonal shape, it is easy to bend in the thickness direction. The cross-sectional shape of the finger contact portion 50 may be other shapes such as a quadrangular shape as long as the front side is flat.

The position B of the end portion on the rear end side where the width of the neck portion 4 becomes constant is preferably 45 mm to 65 mm from the front end of the head portion 3 . The width of the neck portion 4 at the position B is preferably 5.0 mm to 6.0 mm. The thickness of the soft portion 74 on the outer side in the width direction of the hard portion 64 at the position B is preferably 0.7 mm to 1.1 mm.

The width of the grip portion 5 at the position D is preferably 13.5 mm to 16.0 mm. The thickness of the soft portion 75 on the outer side in the width direction of the hard portion 65 at the position D is preferably 2.1 mm to 2.5 mm. The thickness of the grip portion 5 at the position D is preferably 8.0 mm to 10.0 mm.

The ratio of the width of the neck portion 4 at the position B to the width of the grip portion 5 at the position D is preferably 1:2.0 to 1:3.0. In addition, the thickness of the soft portion 74 located on the outer side in the width direction than the hard portion 64 in the neck portion 4 in position B is the same as the thickness of the soft portion 75 located on the outer side in the width direction than the hard portion 65 in the grip portion 5 in the position D. The ratio of the thickness is preferably 1:2.0 to 1:4.0.

Preferably, from the thickness of the soft portion 74 located at the outer side in the width direction of the harder portion 64 at position B to the thickness of the soft portion 75 located at the outer side in the width direction of the harder portion 65 in the grip portion 5 at position D The rate of increase is greater than the rate of increase from the width of the neck portion 4 at the position B to the width of the grip portion 5 at the position D.

By providing the soft part 75 in the above-mentioned range in the flat-shaped finger contact part 50, moderate flexibility can be maintained, and the effect of not being excessively bent can be obtained. In addition, as the width increases from the position B to the position D, by increasing the thickness increase ratio of the soft portion 74 and the soft portion 75 in the width direction, constant deformability can be imparted to the finger contact portion 50 . Therefore, when the neck is bent by pressing the back side, the head 3 , the neck 4 and the grip portion 5 can be deformed integrally. The value represented by the width of the grip portion 5 at the position D/the thickness of the grip portion 5 at the position D is preferably 1.4 or more and 1.8 or less.

In the finger contact portion 50 , the hard portion 65 with the upper surface 56 formed at the center in the width direction is exposed on the front side, and the soft portion 75 is exposed on both sides in the width direction across the hard portion 65 . More specifically, the soft portion 75 extends beyond the boundary position C with the neck portion 4 on the side surfaces 52 on both sides of the hard portion 65 to a position that exceeds the position D where the finger contact portion 50 becomes the maximum width to cover the side surfaces 52 . . By arranging the soft portion 75 also on the side surface 52 of the finger contact portion 50, the elasticity in the width direction can be maintained.

In addition, as shown in FIG. 2 , in the finger contact portion 50 , the hard portion 65 has a substantially elliptical shape whose width gradually expands toward the rear end side starting from the center in the width direction of the position C as a starting point. The rear end portion of the finger contact portion 50 gradually narrows and changes on the rear end side from the rear end side end of the soft portion 75 exposed on the front side after the hard portion 65 expands in a substantially elliptical shape toward the rear end side. Position F for constant width. That is, the rear end portion of the finger contact portion 50 is the position F where the two ridge lines on the front side are connected. As described above, the position F is the position where the ninth curve region E9 shows a minimum value.

The starting position of the finger contact portion 50 in the longitudinal direction is the position of the starting point where the hard portion 65 is exposed on the front side. In other words, the starting position of the finger contact portion 50 in the longitudinal direction is the position at the rear end of the neck portion 4 where the soft portion 74 covers the entire circumference. The start position of the finger contact portion 50 in the longitudinal direction is the same position C as the vertex 51 in the longitudinal direction. In addition, when the position where the seventh curved area E7 and the eighth curved area E8 intersect in the front view of the predetermined position C is not clear, it is set to protrude from the grip portion 5 toward the neck 4 in the side view. The ridgeline is at the position closest to the 4 sides of the neck. The position of the finger contact portion 50 is preferably a region of 0 mm to 30 mm from the boundary position C between the neck portion 4 and the grip portion 5 toward the rear end side.

As shown in the side view of FIG. 1 , the finger contact portion 50 (refer to the front view of FIG. 2 ) is also formed at the position E where the grip portion 5 has a minimum thickness, and the hard portion 65 is thin, so it is gradually covered by the soft portion 75 , thereby suppressing bending while remaining elastic. The grip portion 5 is not provided with the soft portion 75 at the rear end side of the finger contact portion 50, and is not bent toward the front side. Therefore, by exposing the soft portion 75 on the back side and arranging it in a linear shape, it is possible to achieve the difference from the rigid portion 75 only. The portion 65 has flexibility in the thickness direction compared to the case where the grip portion 5 is formed.

The position E is preferably located in the range of 7 mm to 20 mm from the position C to the rear end side in the long axis direction. The value represented by (thickness of grip portion 5 at position E)/(thickness of grip portion 5 at position C) is preferably 0.4 or more and 0.7 or less, and more preferably 0.5 or more and 0.6 or less. The thickness of the grip portion 5 at the position C is, as an example, 10.5 mm to 12.5 mm. The thickness of the grip portion 5 at the position E is, as an example, 6.0 mm to 7.5 mm.

As shown in FIG. 3 , the grip portion 5 has, as an example, a finger contact portion 55 on the back side of the finger contact portion 50 on which the index finger is abutted. The finger contact portion 55 is formed in a substantially elliptical shape. The finger contact portion 55 is formed of a soft portion 75 which covers the hard portion 65 and is exposed on the back side. On the back side of the grip portion 5 , the soft portion 75 is sandwiched by the hard portion 65 , and is exposed at the center in the width direction so as to be coplanar with the hard portion 65 and extends to the end portion on the rear end side of the grip portion 5 . near by.

Therefore, in the brush body 2, the first region R1 where the soft portion 74 covers the entire circumference of the hard portion 64 from the neck portion 4 toward the rear end side of the grip portion 5 is sequentially arranged, and the soft portion 75 only covers the side surface 52 and the back side with the hard portion. The second region R2 of the 65 and the third region R3 of the hard portion 65 are covered only on the back side of the soft portion 75 . By adopting this structure, the head 3 , the neck 4 and the grip 5 can maintain elasticity as a whole in the longitudinal direction so as to draw a continuous series of arcs.

As a value represented by (thickness of soft portion 75 on the back side at position E)/(thickness of grip portion 5 at position E), 0.1 or more and 0.3 or less are preferable. When the said value is less than 0.1, there exists a possibility that flexibility may fall. When the said value exceeds 0.3, there exists a possibility that the curvature to the back side from the position E as a starting point may become large too much. By making the said value into 0.1 or more and 0.3 or less, the moderate softness|flexibility with respect to the force to the back surface side can be provided in the position E. The thickness of the soft portion 75 at the position E is, as an example, 1.0 mm.

As shown in FIG. 2 , the pair of ridgelines 57 intersecting the upper surface 56 and the side surface 52 gradually approaches from the position D toward the rear end side, and changes to a constant width at the position F. As shown in FIG. In the ninth curve region E9, the hard portion 65 is constricted at the position F in a plan view and shows a minimum value. By providing the ridgeline 57 on the front side of the grip portion 5 , the grip portion 5 is hard to bend, and the grip portion 5 can be firmly gripped. In addition, since the grip portion 5 has a minimum value in which the hard portion 65 is narrowed in the width direction, the grip portion 5 can maintain flexibility. It is preferable that the position in the long axis direction of the constriction in the width direction (minimum value) is 45% to 60% from the front end side of the head 3 with respect to the entire length of the toothbrush 1 .

The maximum width of the finger contact portion 55 at the position D is preferably 1.3 times to 1.8 times the minimum width of the necked grip portion 5 at the position F. The maximum width of the grip portion 5 at the position G is preferably 1.3 times to 1.8 times the minimum width of the necked grip portion 5 at the position F. FIG. The maximum width of the finger contact portion 55 at the position D is, for example, 14.0 mm to 16.0 mm. The minimum width of the constricted grip portion 5 at the position F is, for example, 9.0 mm to 11.0 mm. The maximum width of the grip portion 5 at the position G is, for example, 14.0 mm to 16.0 mm.

The thickness of the grip portion at the position F is preferably 1.2 to 1.6 times the thickness of the grip portion at the position E. The thickness of the grip portion at the position G is preferably 1.5 times to 2.3 times the thickness of the grip portion at the position E. Further, it is preferable that (thickness of the grip portion at position G)>(thickness of the grip portion at position F)>(thickness of the grip portion at position E). The thickness of the grip portion at the position F is, for example, 7.5 mm to 9.5 mm. The thickness of the grip portion at the position G is, for example, 12.0 mm to 14.0 mm.

The end on the front end side of the position where the pair of ridgelines 57 have a constant width (position F) is a position that is 50% to 60% from the front end side of the head 3 with respect to the entire length of the toothbrush 1 . The front end side of the part 3 is a position of 95 mm to 120 mm, and is a position of 5 mm to 10 mm from the position D. The end on the rear end side of the portion where the pair of ridge lines 57 have a constant width is a position from the position F by 80 mm to 90 mm. FIG. 7 is a cross-sectional view of the grip portion 5 at the position F. As shown in FIG. As shown in FIG. 7 , the cross section of the grip portion 5 at the position F is a substantially pentagonal shape having an apex on the front side. The pair of ridge lines 57 are preferably connected at the position F to form one. The pair of ridge lines 57 gradually spreads from the end on the rear end side of the constant width portion to the position H where the thickness of the grip portion 5 becomes the maximum. The position H is a position 160 mm to 190 mm from the front end side of the head 3 , and is a position 50 mm to 70 mm from the position F to the rear end side.

The width of the side surface 52 at the position F is 3 mm to 7 mm. The width of the side surface 52 extends from the position F to the rear end side, and is 12 mm to 17 mm at the position H. The pair of side surfaces 52 intersect each other at an intersecting angle θ. The intersection angle θ represents the range occupied by the hard portion 65 in the cross section. The intersection angle θ gradually decreases from the position F where the distance (width) between the pair of ridge lines 57 becomes the smallest toward the position H where the thickness of the grip portion 5 becomes the largest. The intersection angle θ is preferably gradually reduced toward the rear end side of the grip portion 5 in a region of 95% or less of the entire length of the grip portion 5 from the front end of the grip portion 5 to the rear end side. For example, when the intersection angle θ becomes the smallest at a position 179 mm from the front end of the head 3 with respect to the total length of 190 mm of the toothbrush 1 (position of 179 mm/190 mm=94.2%), the angle θ is smaller than this position. On the rear end side, the outline of the front side faces the rear side and has a circular arc in a side view, so the side surface 52 is not formed.

FIG. 8 is a cross-sectional view of the grip portion 5 at the position H. As shown in FIG. As shown in FIG. 8 , the cross section of the grip portion 5 at the position H is a substantially triangular shape having an apex on the front side. The cross section of the grip portion 5 changes in order from the rear end side toward the finger contact portion 50 into a substantially triangular shape, a substantially pentagonal shape, and a substantially hexagonal shape. As a result, the rear end is thick, the mid-abdomen is thin, and straight, and when held in a grasping manner, the entire palm can be firmly and stably held. The cross section of the grip portion 5 at the position H does not necessarily need to be a substantially triangular shape.

As the intersection angle θ gradually decreases from the position F toward the position H, the effect of suppressing the elasticity toward the rear end side of the grip portion 5 increases. That is, the deformability can be varied according to the cross section of the substantially triangular shape in which the angles of the vertexes on the front side are different. As an example, the intersection angle θ at the position F is preferably 90° to 120°, and the intersection angle θ at the position H is preferably 50° to 70°.

In the toothbrush 1 of the above-described structure, the neck portion 4 is 70% or more of the length in the long-axis direction, and is the boundary position with the grip portion 5, and the entire circumference of the hard portion 60 is covered by the soft portion 70. The value represented by S2/S1, which is the relationship between the cross-sectional area S1 of the soft portion 70 at the position A and the cross-sectional area S2 of the soft portion 70 at the position C, is 4.5 or more and 6.0 or less, to maintain stable grip. At the same time, it can be deformed in a wide range and not locally.

[Example] Hereinafter, the effects of the present invention will be further clarified by examples. In addition, this invention is not limited to the following Example, It can change suitably in the range which does not change the summary, and can implement.

(Example 1 to Example 7, Comparative Example 1 to Comparative Example 6) In this example, according to the specifications shown in the following [Table 1], [Table 2], [Table 3], and [Table 4], Examples 1 to 7, and Comparative Examples 1 to 6 were produced samples of toothbrushes. Each part of the toothbrush of each example was made into the dimension shown in Table 1 and Table 2. The hard resin of the brush body uses PP resin, and the soft resin uses thermoplastic elastomer (Thermoplastic Elastomer, TPE).

Compared with the sample of Example 1, the sample of Example 2 was made to have the same overall width at the position C, and the thickness of the elastic body in the width direction was increased. The sample of Example 3 was made to have the same overall width at position C and the thickness of the elastic body in the width direction was reduced relative to the sample of Example 1. In the sample of Example 4, the total thickness at the position C was made the same as that of the sample of Example 1, and the thickness in the thickness direction of the elastic body was increased. The sample of Example 5 was made to have the same total thickness at the position C and the thickness in the thickness direction of the elastomer was reduced relative to the sample of Example 1. The sample of Example 6 has a structure in which the elastic body is not arranged on the side surface of the finger contact portion with respect to the sample of Example 1. The sample of Example 7 has a structure that does not have a ridge on the front side of the grip portion with respect to the sample of Example 1.

In the sample of Comparative Example 1, the coverage in the long-axis direction of the elastic body at the neck portion was reduced as compared with the sample of Example 1. The sample of Comparative Example 2 had the same total width and total thickness at position C, and increased the thickness in the width direction and the thickness in the thickness direction of the elastic body compared to the sample in Example 1. The sample of Comparative Example 3 had the same total width and total thickness at position C, and reduced the thickness in the width direction and the thickness in the thickness direction of the elastic body compared to the sample in Example 1. In the sample of Comparative Example 4, the total thickness at the position A and the position C was the same as that of the sample in Example 1, and the thickness in the width direction of the elastic body was reduced. The sample of Comparative Example 5 had the same overall width at the position C as compared to the sample of Comparative Example 3, and further reduced the thickness of the elastic body in the width direction. The sample of Comparative Example 6 has a structure that does not use an elastomer compared to the sample of Example 1.

[Evaluation method] (1) Ease of force control [experiment method] The person in charge of development carried out an evaluation of the sense of use (n=7), and each item was evaluated on a 7-level absolute basis, and an evaluation of 5 points or more for each item was set as the target value. <Judgment Criteria> ◎Double circle mark: average score of 6.0 or more ○Circle mark: The average score is more than 5.0 points and less than 6.0 points ×cross mark: average score less than 5.0

(2) The real feeling of cleaning the whole tooth (the feeling of transmitting force to the tooth) The person in charge of development carried out an evaluation of the sense of use (n=7), and each item was evaluated on a 7-level absolute basis, and an evaluation of 5 points or more for each item was set as the target value. <Judgment Criteria> ◎: Average score of 6.0 points or more ○: Average score is more than 5.0 points and less than 6.0 points ×: Average score less than 5.0

(3) Excellent degree of comfort in contact with the gums (good degree of cushioning applied to the gums) The person in charge of development carried out an evaluation of the sense of use (n=7), and each item was evaluated on a 7-level absolute basis, and an evaluation of 5 points or more for each item was set as the target value. <Judgment Criteria> ◎: Average score of 6.0 points or more ○: Average score is more than 5.0 points and less than 6.0 points ×: Average score less than 5.0

[Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Coverage of the entire circumference of the elastomer with respect to the long axis direction of the neck 80% 80% 80% 75% 75% 80% 80% Cross-sectional area ratio S2/S1 5.3 6.0 4.5 5.3 4.6 5.3 5.3 Cross-sectional area ratio S3/S4 3.0 3.9 2.3 3.1 2.8 3.0 3.0 Cross-sectional area ratio S4/S3 33% 26% 44% 32% 35% 33% 33% Composition ratio of soft resin at position C 67% 74% 56% 68% 65% 67% 67% Cross-sectional shape of finger contact part wide flat wide flat wide flat wide flat wide flat wide flat wide flat Covered area of the elastic body at the starting position of the grip side and back side and back side and back side and back side and back side and back side and back (C2∕A2)∕(C1∕A1) 3.3 4.3 2.6 1.5 9.1 3.3 3.3 Thickness C2 (mm) 3.3 4.3 2.6 3.3 3.6 3.3 3.3 Thickness C1 (mm) 1.0 1.0 1.0 1.8 0.5 1.0 1.0 (C12∕C11)∕(A12∕A11) 1.03 1.03 1.03 0.89 1.19 1.03 1.03 (C22∕C21)∕(A22∕A21) 0.80 0.57 0.96 0.80 0.73 0.80 0.80 Elastomers for Finger Contacts - (TPE) TPE on side and back TPE on side and back TPE on side and back TPE on side and back TPE on side and back No TPE on the sides TPE on side and back Change of the area covered by the elastic body from the neck to the rear side of the grip Covered all the way → side and back → back Covered all the way → side and back → back Covered all the way → side and back → back Covered all the way → side and back → back Covered all the way → side and back → back Covered all week → back Covered all the way → side and back → back Expansion to the rear end side after a pair of ridge lines on the rear end side of the finger contact portion becomes a constant distance The distance increases toward the rear end The distance increases toward the rear end The distance increases toward the rear end The distance increases toward the rear end The distance increases toward the rear end The distance increases toward the rear end No change in distance toward the rear end Changes to the rear end side of the intersection angle between the outer side surfaces of a pair of ridge lines become smaller become smaller become smaller become smaller become smaller become smaller no change in angle Ease of Force Control ◎ 〇 〇 〇 〇 ◎ ◎ The real feeling of cleaning the whole tooth (the feeling of transmitting force to the tooth) ◎ 〇 ◎ 〇 〇 ◎ 〇 Excellent degree of comfort in contact with the gums (good degree of cushioning applied to the gums) ◎ 〇 〇 〇 〇 〇 ◎

[Table 2] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Coverage of the entire circumference of the elastomer with respect to the long axis direction of the neck 60% 80% 80% 80% 80% 0% Cross-sectional area ratio S2/S1 5.0 6.2 3.7 3.9 3.6 0.0 Cross-sectional area ratio S3/S4 3.0 4.6 2.2 2.0 1.9 1.0 Cross-sectional area ratio S4/S3 33% twenty two% 46% 50% 52% 100% Composition ratio of soft resin at position C 67% 78% 54% 50% 48% 0% Cross-sectional shape of finger contact part wide flat wide flat wide flat wide flat wide flat wide flat Covered area of the elastic body at the starting position of the grip side and back side and back side and back side and back side and back none (C2∕A2)∕(C1∕A1) 2.4 2.8 5.2 1.0 4.7 - Thickness C2 (mm) 3.3 4.5 2.6 2.0 2.1 0.0 Thickness C1 (mm) 1.0 1.6 0.5 1.0 0.5 0.0 (C12∕C11)∕(A12∕A11) 1.00 0.91 1.12 0.91 1.12 1.00 (C22∕C21)∕(A22∕A21) 0.93 0.48 0.99 1.13 1.04 1.00 Elastomers for Finger Contacts - (TPE) TPE on side and back TPE on side and back TPE on side and back TPE on side and back TPE on side and back No TPE Change of the area covered by the elastic body from the neck to the rear side of the grip Covered all the way → side and back → back Covered all the way → side and back → back Covered all the way → side and back → back Covered all the way → side and back → back Covered all the way → side and back → back No TPE Expansion to the rear end side after a pair of ridge lines on the rear end side of the finger contact portion becomes a constant distance The distance increases toward the rear end The distance increases toward the rear end The distance increases toward the rear end The distance increases toward the rear end The distance increases toward the rear end The distance increases toward the rear end Changes to the rear end side of the intersection angle between the outer side surfaces of a pair of ridge lines become smaller become smaller become smaller become smaller become smaller become smaller Ease of Force Control × × × × × × The real feeling of cleaning the whole tooth (the feeling of transmitting force to the tooth) 〇 × 〇 〇 〇 × Excellent degree of comfort in contact with the gums (good degree of cushioning applied to the gums) × × × × × ×

[table 3] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Width A21 (mm) 5.3 5.3 5.3 5.3 5.3 5.3 Width A22 (mm) 3.4 3.4 3.4 3.4 3.4 3.4 Width A2 (mm) 1.0 1.0 1.0 1.0 1.0 1.0 Thickness A11 (mm) 5.3 5.3 5.3 5.3 5.3 5.3 Thickness A12 (mm) 3.4 3.4 3.4 3.6 3.2 3.4 Thickness A11-(A1+A12) (mm) 1.0 1.0 1.0 1.0 1.0 1.0 Thickness A1 (mm) 1.0 1.0 1.0 0.8 1.2 1.0 A12/A11 0.6 0.6 0.6 0.7 0.6 0.6 A22/A21 0.6 0.6 0.6 0.6 0.6 0.6 Total cross-sectional area at position A (mm ² ) 24.7 24.7 24.7 25.7 24.7 24.7 Cross-sectional area of hard part at position A (mm ² ) 10.4 10.4 10.4 11.0 8.4 10.4 S1 (mm ² ) 14.3 14.3 14.3 14.7 16.3 14.3 Width C21 (mm) 13.5 13.5 13.5 13.5 13.5 13.5 Width C22 (mm) 6.9 4.9 8.3 6.9 6.3 6.9 Width C2 (mm) 3.3 4.3 2.6 3.3 3.6 3.3 Thickness C11 (mm) 11.6 11.6 11.6 11.6 11.6 11.6 Thickness C12 (mm) 7.7 7.7 7.7 6.9 8.2 7.7 Thickness C11-(C1+C12) (mm) 2.9 2.9 2.9 2.9 2.9 2.9 Thickness C1 (mm) 1.0 1.0 1.0 1.8 0.5 1.0 C12/C11 0.7 0.7 0.7 0.6 0.7 0.7 C22/C21 0.5 0.4 0.6 0.5 0.5 0.5 S3 (mm ² ) 115.0 115.0 115.0 115.0 115.0 115.0 S4 (mm ² ) 38.5 29.6 50.2 37.4 40.6 38.5 S2 (mm ² ) 76.5 85.4 64.8 77.6 74.4 76.5 S3/S4 3.0 3.9 2.3 3.1 2.8 3.0 S2/S1 5.3 6.0 4.5 5.3 4.6 5.3

[Table 4] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Width A21 (mm) 6.2 5.3 5.3 5.3 5.3 5.3 Width A22 (mm) 3.4 3.7 3.3 3.3 3.5 3.4 Width A2 (mm) 1.4 0.8 1.0 1.0 0.9 1.0 Thickness A11 (mm) 6.2 5.3 5.3 5.3 5.3 5.3 Thickness A12 (mm) 4.1 3.6 3.4 3.9 3.4 3.4 Thickness A11-(A1+A12) (mm) 1.1 1.0 1.0 1.0 1.0 1.0 Thickness A1 (mm) 1.0 0.8 1.0 0.5 1.0 1.0 A12/A11 0.7 0.7 0.6 0.7 0.6 0.6 A22/A21 0.5 0.7 0.6 0.6 0.7 0.6 Total cross-sectional area at position A (mm ² ) 29.6 24.7 26.7 24.7 24.7 24.7 Cross-sectional area of hard part at position A (mm ² ) 14.3 10.3 10.2 10.0 9.2 10.4 S1 (mm ² ) 15.3 14.4 16.5 14.7 15.5 14.3 Width C21 (mm) 13.5 13.5 13.5 13.5 13.5 13.5 Width C22 (mm) 6.9 4.5 8.3 9.5 9.3 6.9 Width C2 (mm) 3.3 4.5 2.6 2.0 2.1 3.3 Thickness C11 (mm) 11.6 11.6 11.6 11.6 11.6 11.6 Thickness C12 (mm) 7.7 7.1 8.2 7.7 8.2 7.7 Thickness C11-(C1+C12) (mm) 2.9 2.9 2.9 2.9 2.9 2.9 Thickness C1 (mm) 1.0 1.6 0.5 1.0 0.5 1.0 C12/C11 0.7 0.6 0.7 0.7 0.7 0.7 C22/C21 0.5 0.3 0.6 0.7 0.7 0.5 S3 (mm ² ) 115.0 115.0 115.0 115.0 115.0 115.0 S4 (mm ² ) 38.5 25.1 53.4 57.4 59.9 38.5 S2 (mm ² ) 76.5 89.9 61.6 57.6 55.1 76.5 S3/S4 3.0 4.6 2.2 2.0 1.9 3.0 S2/S1 5.0 6.2 3.7 3.9 3.6 5.3

As shown in [Table 1] and [Table 2], the coverage rate of the entire circumference of the elastic body with respect to the long axis direction of the neck is 70% or more, and the cross-sectional area S1 of the elastic body at the position A and the position In the samples of Examples 1 to 7 in which the cross-sectional area S2 of the elastic body at C, the value represented by S2/S1 is 4.5 or more and 6.0 or less, the easiness of force control and the real feeling of cleaning the whole tooth (to the tooth The feeling of transmission force) and the goodness of the contact comfort with the gums (the goodness of the cushioning properties applied to the gums) all received good evaluations.

Furthermore, with respect to the total cross-sectional area S3 at the boundary position C and the cross-sectional area S4 of the hard portion, in the samples of Examples 1 to 7 in which the value represented by S3/S4 was 2.0 or more and 4.0 or less, the force control was easy. All of the properties, the real feeling of cleaning of the entire tooth (the feeling of transmitting force to the teeth), and the goodness of the contact comfort with the gums (the goodness of the cushioning properties applied to the gums) were all well evaluated.

In addition, in the cross section at the position A, the thickness A1 of the elastic body located on the back side in the thickness direction, the thickness A2 of the elastic body located on the outer side in the width direction than the hard portion, and the cross section at the position C Among them, the thickness 11 of the elastic body located on the back side in the thickness direction and the thickness C2 of the elastic body located on the outer side in the width direction than the hard part satisfy the relationship of (C2/A2)/(C1/A1)>2.5 In the samples of Examples 1 to 7, the ease of force control, the real feeling of cleaning the whole tooth (the feeling of transmitting force to the teeth), and the goodness of the contact comfort with the gums (the amount of cushioning applied to the gums) were excellent. good grades) were all rated as good.

The maximum thickness A11 of the neck at position A and the maximum thickness A12 of the hard part, the maximum width A21 of the neck and the maximum width A22 of the hard part at the position A, the maximum thickness C11 of the neck at the position C and the hard part The maximum thickness C12 of the portion, the maximum width C21 of the neck portion at the position C, and the maximum width C22 of the hard portion, the values represented by (C12/C11)/(A12/A11) are 0.95 or more and 1.15 or less Examples 1 to 1 In the samples of Example 3 and Example 6 to Example 7, the ease of force control, the real feeling of cleaning the whole tooth (the feeling of transmitting force to the teeth), and the goodness of the contact comfort with the gums (the amount of force applied to the gums) were observed. The excellent degree of cushioning properties) all received good evaluations. In the samples of Example 1 and Example 4 to Example 7, where the value represented by (C22/C21)/(A22/A21) is 0.70 or more and 0.90 or less, the ease of force control and the real feeling of cleaning the entire tooth Good evaluations were obtained in all of the excellent degree of (the feeling of transmitting force to the teeth) and the comfort of contact with the gums (the good degree of the cushioning properties applied to the gums).

On the other hand, the whole circumference coverage of the elastic body with respect to the long axis direction of the neck is less than 70%, and the relationship of (C2/A2)/(C1/A1)>2.5 is not satisfied, (C22/C21 )/(A22/A21) in the samples of Comparative Example 1 in which the value represented by 0.70 or more and 0.90 or less was out of the range of 0.70 or more and 0.90 or less, with regard to the ease of force control and the goodness of the contact comfort with the gums (the cushioning properties applied to the gums). good grades), did not get a good evaluation.

In addition, when the value represented by S2/S1, which is the cross-sectional area ratio, deviates from the range of 4.5 or more and 6.0 or less, and the value represented by S3/S4, which is the cross-sectional area ratio, deviates from the range of 2.0 or more and 4.0 or less, (C12/C11) In the samples of Comparative Example 2 in which the value represented by /(A12/A11) deviates from the range of 0.95 or more and 1.15 or less, and the value represented by (C22/C21)/(A22/A21) deviates from the range of 0.70 or more and 0.90 or less, All evaluation items did not get a good evaluation.

Comparative Example 3 in which the value represented by S2/S1, which is the cross-sectional area ratio, deviates from the range of 4.5 or more and 6.0 or less, and the value represented by (C22/C21)/(A22/A21) deviates from the range of 0.70 or more and 0.90 or less. Among the samples, good evaluations were not obtained regarding the ease of force control and the goodness of the contact comfort with the gums (the goodness of the cushioning properties applied to the gums).

When the value represented by S2/S1 as the cross-sectional area ratio deviates from the range of 4.5 or more and 6.0 or less, the value represented by (C12/C11)/(A12/A11) deviates from the range of 0.95 or more and 1.15 or less, (C22/C21 )/(A22/A21) in the samples of Comparative Example 4 in which the value represented by 0.70 or more and 0.90 or less was out of the range of 0.70 or more and 0.90 or less, with regard to the ease of force control and the goodness of the contact comfort with the gums (the cushioning properties applied to the gums). good grades), did not get a good evaluation.

The value represented by S2/S1 as the cross-sectional area ratio deviates from the range of 4.5 or more and 6.0 or less, and the value represented by S3/S4 as the cross-sectional area ratio deviates from the range of 2.0 or more and 4.0 or less, (C22/C21)/( In the samples of Comparative Example 5 in which the value represented by A22/A21) deviates from the range of 0.70 or more and 0.90 or less, the easiness of force control and the goodness of the contact comfort with the gums (the goodness of the cushioning properties applied to the gums) ), which did not receive good reviews.

In the sample of Comparative Example 6 which has a flat shape long in the thickness direction in the cross section of the finger contact portion, and the sample of Comparative Example 7 which does not have an elastic body, good evaluations were not obtained in all the evaluation items.

The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to the examples. The shapes, combinations, and the like of the respective structural members shown in the above examples are examples, and various changes can be made based on design requirements and the like without departing from the gist of the present invention. [Industrial Availability]

The present invention can be applied to toothbrushes.

1: toothbrush 2: Brush the body 3: head 3a: Flocked surface 4: neck 5: Grip 6: Plant pores 40: Brush 50, 55: finger contact part 51, 51A: Vertex 52: Side (Second Face) 56: Upper surface (first face) 57: Ridgeline 60, 63, 64, 65: Hard part 70, 73, 74, 75: Soft part 73A, 73B: Scraper A, B, D, E, F, G, H, J: Position A1, A2, C1, C2: Thickness of soft part (thickness) A11, C11: Maximum thickness of neck (thickness) A12, C12: Maximum thickness of hard part (thickness) A21, C21: Maximum width of neck (width) A22, C22: Maximum width of neck (width) C: position (boundary position) E1: The first curve area E2: Curved Surface (Second Curved Area) E3: The third curve area E4: Fourth Curve Area E5: Fifth curve area E6: The sixth curve area E7: Seventh Curve Area E8: Eighth curve area E9: Ninth Curve Area E10: Tenth curve area L1: The first straight line area L2: Second straight line area L3: The third straight line area R1: The first area R2: The second area R3: The third area θ: cross angle

FIG. 1 : is a figure which shows embodiment of this invention, and is a side view which shows the structure of the toothbrush 1. As shown in FIG. 2 : is the front view which looked at the toothbrush 1 from the hair-implantation surface 3a side. FIG. 3 is a back view of the toothbrush 1 viewed from the back side. FIG. 4 is a cross-sectional view at position A perpendicular to the longitudinal direction of the neck 4 . FIG. 5 is a cross-sectional view orthogonal to the longitudinal direction of the neck 4 at a position C of the boundary between the neck 4 and the grip portion 5 . FIG. 6 is a cross-sectional view of the grip portion 5 at the position D where the finger contact portion 50 has the maximum width. FIG. 7 is a cross-sectional view of the grip portion 5 at a position F where the ninth curve region E9 shows a minimum value when viewed from the front. 8 is a cross-sectional view of the grip portion 5 from the end portion on the rear end side of the portion where the pair of ridge lines 57 have a constant width to the position H where the thickness of the grip portion 5 becomes the largest.

1: toothbrush

2: Brush the body

3: head

3a: Flocked surface

4: neck

5: Grip

40: Brush

50, 55: finger contact part

51, 51A: Vertex

52: side (second face)

60, 63, 64, 65: Hard part

70, 73, 74, 75: Soft part

A, B, D, E, F, G, H, J: Position

C: position (boundary position)

E1: The first curve area

E2: Curved Surface (Second Curved Area)

E3: The third curve area

E4: Fourth Curve Area

E5: Fifth curve area

E6: The sixth curve area

L1: The first straight line area

L2: Second straight line area

R1: The first area

R2: The second area

R3: The third area

Claims (11)

A toothbrush comprising: The head is located on the front end side in the long-axis direction and has a hair-implanted surface; a grip portion disposed on the rear end side of the head portion; and a neck, disposed between the head and the grip, The neck portion and the grip portion respectively have: a hard portion formed of a hard resin; and a soft portion formed of a soft resin and covering at least a part of the hard portion, In the neck portion, the length of the neck portion in the long-axis direction is 70% or more and is a boundary position with the grip portion, and the entire circumference of the hard portion is covered by the soft portion , In the cross section orthogonal to the long axis direction, if the position of the end portion on the distal end side in the long axis direction of the soft portion in the neck portion is A, the position A is The cross-sectional area of the soft portion at the position C is set as S1, the boundary position in the long axis direction is set as C, and the cross-sectional area of the soft portion at the position C is set as S2, Then, the value represented by S2/S1 is 4.5 or more and 6.0 or less. The toothbrush of claim 1, wherein If the total cross-sectional area of the neck at the boundary position perpendicular to the long-axis direction is S3, and the cross-sectional area of the hard portion is S4, Then, the value represented by S3/S4 is 2.0 or more and 4.0 or less. The toothbrush of claim 2, wherein The grip portion has a finger contact portion on a front side facing the hair-implantation surface in a thickness direction orthogonal to the hair-implantation surface, In the cross section, the finger contact portion has a flat shape whose length in the width direction orthogonal to the long axis direction and the thickness direction is longer than the length in the thickness direction. The toothbrush of claim 3, wherein When viewed from the side in the width direction, the finger contact portion has a convex-shaped apex on the front side, and has a curved surface of a concave shape having a center of curvature on the front side from the vertex toward the rear end side, In the front view viewed from the front side, the width between the outer contour lines in the width direction is expanded from the boundary position to a position where the maximum width of the finger contact portion is reached, In the finger contact portion, the hard portion is exposed on the front side, The soft portion covers the hard portion on the side surfaces of both sides in the width direction sandwiching the finger contact portion until it exceeds the boundary position and becomes the maximum width position. The toothbrush of claim 4, wherein The soft portion extends to the rear end side beyond the boundary position at least on the back side opposite to the front side in the thickness direction. The toothbrush of claim 5, wherein From the neck portion toward the rear end side of the grip portion, a first region in which the soft portion covers the entire circumference of the hard portion, and the soft portion is arranged only on the side surface and the back surface side in this order. The second region covering the hard portion and the soft portion covering the third region covering the hard portion only on the back side. The toothbrush of any one of claims 4 to 6, wherein The grip portion at the position of the maximum width has, in the cross section, a first face portion facing the front side and extending in the width direction, and a second face portion to be aligned with the first face portion. The intersections of the one surface face each serve as a ridgeline, and are inclined toward the back side opposite to the front side in the thickness direction from the intersections toward the outer side in the width direction, respectively, The distance between the ridge lines in the width direction gradually decreases toward the rear end side from the position where the width becomes the maximum, and then gradually expands to the position where the thickness of the grip portion becomes the maximum. The toothbrush of claim 7, wherein Among the intersecting angles of a pair of the second surface portions, the intersecting angle representing the range occupied by the hard portion in the cross section is directed from the position where the distance between the ridgelines in the width direction becomes the smallest toward the The position where the thickness of the grip portion becomes the largest gradually decreases. The toothbrush of any one of claims 1 to 8, wherein In the cross section at the position A, if the soft part is located on the back side opposite to the hair-implantation surface in the thickness direction perpendicular to the hair-implantation surface of the hard part, The thickness of the part is A1, the thickness of the soft part located on the outer side in the width direction orthogonal to the long-axis direction and the thickness direction is A2, and the thickness of the soft part is A2, In the cross section at the position C, if the thickness of the soft portion located on the back side in the thickness direction relative to the hard portion is C1, the thickness of the soft portion located on the back side in the thickness direction relative to the hard portion If the thickness of the soft portion at the outer side in the width direction is set to C2, it satisfies (C2/A2)/(C1/A1)>2.5 Relationship. The toothbrush of claim 9, wherein The thickness C2 is more than 2.5 mm and less than 4.5 mm, The thickness C1 is 0.7 mm or more and 1.5 mm or less. The toothbrush of any one of claims 1 to 10, wherein If the maximum thickness of the neck at the position A is A11, and the maximum thickness of the hard portion is A12, Let the maximum width of the neck at the position A be A21, the maximum width of the hard part be A22, Let the maximum thickness of the neck at the position C be C11, and the maximum thickness of the hard part be C12, Let the maximum width of the neck at the position C be C21, and the maximum width of the hard part be C22, Then the value represented by (C12/C11)/(A12/A11) is 0.95 or more and 1.15 or less, The value represented by (C22/C21)/(A22/A21) is 0.70 or more and 0.90 or less.

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