Toothbrush

Abstract

This invention provides a toothbrush that achieves conformity to the object being cleaned regardless of brushing method or technique. The hard part includes a head, a grip, and a neck. Position A is designated as the front end of the neck, and position B is designated as the rear end of the neck. At position A, the length in both the thickness and width directions of the neck is 3.0 mm or more and 4.3 mm or less. The ratio of the length in the width direction of the neck at position A to the length in the width direction of the neck at position B is 0.30 or more and 0.60 or less. The ratio of the length in the thickness direction of the neck at position A to the length in the thickness direction of the neck at position B is 0.30 or more and 0.60 or less. The bending originates from the grip in at least one of the bending in the width direction of the brush body measured by method (α) and the bending in the thickness direction of the brush body measured by method (β).

Description

Technical Field

[0001] This invention relates to toothbrushes.

[0002] This application asserts priority based on Japanese Patent Application No. 2021-081747, filed in Japan on May 13, 2021, the contents of which are incorporated herein by reference. Background Technology

[0003] In toothbrushes with a thin neck, designed for ease of use within the mouth, the front part of the neck is made thinner, while the area near the boundary between the neck and the grip is made thicker than the front part to ensure strength, thereby preventing the neck from bending from the rear side.

[0004] In addition, Patent Document 1 discloses a toothbrush in which the brush body is shaped like an S-shape in a side view, so that the flexed shape is close to a "straight line shape", thus achieving a brush body shape that is highly operable and has a high degree of cleaning effect on the gaps between teeth.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: International Publication No. 2018 / 079114

[0008] The technical problem that the invention aims to solve

[0009] The oral cavity contains many uneven surfaces, such as between teeth and at the neck of teeth. Therefore, in order to achieve a high degree of cleaning in these spaces, it is important that the bristles contact these uneven surfaces at an appropriate angle. However, the toothbrush disclosed in Patent Document 1 has its flexing direction limited to the thickness direction of the head, which cannot be considered sufficient for cleaning and maneuverability in the interdental spaces.

[0010] The inventors' research revealed that, in the toothbrush described above, by refining the neck, the head can move more freely during brushing. On the other hand, considering that brushing methods still differ among users, in order for the bristles to contact the surface at an appropriate angle in accordance with the contours, a structure in which the head can move freely at various angles is preferred over one that restricts the direction and amount of deflection. Summary of the Invention

[0011] The present invention was made with consideration of the above aspects, and its object is to provide a toothbrush that achieves a conformity to the object being cleaned without relying on brushing methods and techniques.

[0012] Technical means for solving technical problems

[0013] <1> A toothbrush is provided, characterized by comprising: a bristle-embedded portion composed of multiple bristle tufts; and a brush body extending in the long axis direction, the brush body having a rigid portion formed of hard resin, the rigid portion having: a head located at a front end side in the long axis direction, the bristle-embedded portion being disposed on the bristle-embedded surface; a grip portion located at a rear end side in the long axis direction further than the head; and a neck located between the head and the grip portion; wherein the position is defined as follows: when the position of the front end side of the neck in the long axis direction is designated as A, the position of the rear end side of the neck in the long axis direction is designated as B, the direction orthogonal to the bristle-embedded surface is designated as the thickness direction, and the direction parallel to the bristle-embedded surface and orthogonal to the thickness direction is designated as the width direction; The length of the neck in the thickness direction and the length in the width direction at position A are both 3.0 mm or more and 4.3 mm or less. The ratio of the length of the neck in the width direction at position A to the length of the neck in the width direction at position B is 0.30 or more and 0.60 or less. The ratio of the length of the neck in the thickness direction at position A to the length of the neck in the thickness direction at position B is 0.30 or more and 0.60 or less. In at least one of the bending in the width direction of the brush body measured by the method described below (α) and the bending in the thickness direction of the brush body measured by the method described below (β), the bending originates from the grip portion.

[0014] Method (α): For a position that is 40% of the length of the long axis of the grip from the front end to the rear end of the grip, the height of the front end of the brush body in a fixed state is set as the reference height. In the fixed state, a load of 200g is applied to the center position of the bristle section in the head along the width direction. The starting position of the bending is measured after 10 seconds, and the displacement (in mm) of the front end of the brush body relative to the reference height in the width direction is measured as the bending length.

[0015] Method (β): For a position that is 40% of the length of the long axis of the grip from the front end to the rear end, the height of the front end of the brush body in a fixed state is set as the reference height. In the fixed state, a load of 200g is applied along the thickness direction to the center position of the bristle section in the head along the long axis. The starting position of the bending is measured after 10 seconds, and the displacement (in mm) of the front end of the brush body relative to the reference height in the thickness direction is measured as the bending length.

[0016] <2> according to <1> The toothbrush described herein has a bending length in both the width direction and the thickness direction of 6.0 mm or more and 11.0 mm or less.

[0017] <3> according to <1> or <2> The toothbrush described herein has a rotation angle of 30° or more and 50° or less when the head is rotated about an axis extending along the long axis direction using a force of 20 N·cm.

[0018] <4> according to <1> to <3> The toothbrush described in any one of the following, if the length of the neck in the thickness direction is set as D mm, and the length in the width direction is set as W mm, then W × D at position A... 3 The value represented is set as WD. 3 (A)mm 4 W×D at position B 3 The value represented is set as WD. 3 (B)mm 4 D×W at position A 3 The value represented is set as DW. 3 (A)mm 4 D×W at position B 3 The value represented is set as DW. 3 (B)mm 4 WD 3 (B) is 1200mm 4 Above and 6500mm 4 Below, WD 3 (A) / WD 3 (B) represents a value greater than 0.01 and less than 0.20, DW 3 (B) is 1200mm 4 Above and 6500mm 4 Below, DW 3 (A) / DW 3 (B) represents a value greater than 0.01 and less than 0.20.

[0019] <5> according to <1> to <4> The toothbrush described in any one of the following has a length in the thickness direction and a length in the width direction of the grip portion that is at least 20% of the length of the grip portion in the long axis direction, where the length of the grip portion is at least 4.5 mm and less than 8.0 mm.

[0020] <6> according to <1> to <5> The toothbrush described in any one of the following embodiments, wherein the position of the front end of the grip portion along its long axis is defined as C, the position from the front end of the grip portion to the rear end portion, which is 50% of the length of the grip portion along its long axis, is defined as D, the length of the grip portion in the thickness direction is defined as D mm, the length in the width direction is defined as W mm, and the W×D at position C is defined as... 3 The value represented is set as WD. 3 (C)mm 4 W×D at position D 3 The value represented is set as WD. 3 (D)mm 4 D×W at position C 3 The value represented is set as DW. 3 (C)mm 4 , D×W at position D 3 The value represented is set as DW. 3 (D)mm 4 WD 3 (C) is 410mm 4 Above and 4000mm 4 Below, WD 3 (C) / WD 3 (D) represents a value greater than 0.35 and less than 2.0, DW 3 (C) is 410mm 4 Above and 4000mm 4 Below, DW 3 (C) / DW 3 (D) represents a value greater than 0.35 and less than 2.0.

[0021] <7> according to <6> The toothbrush described herein has a width-direction length of the grip portion at position C that is 0.65 or more and 1.30 or less than the width-direction length of the grip portion at position D, and a thickness-direction length of the grip portion at position C that is 0.65 or more and 1.30 or less than the thickness-direction length of the grip portion at position D.

[0022] <8> according to <6> or <7> The toothbrush described herein has a neck whose length in the thickness direction and its length in the width direction are both constant or gradually increasing in diameter from the front end to the rear end. The neck has a position where at least one of the length in the thickness direction and the length in the width direction is greater than the length in the thickness direction or the length in the width direction between position C and position D in the grip portion. The position E closest to the front end of this position is located at a position more than 3 mm closer to the front end than position B.

[0023] <9> according to <1> to <8> In any one of the toothbrushes described, at least a portion of the grip portion is covered by a soft portion formed of soft resin. In a continuous region extending from the front end to the rear end of the grip portion along its long axis, if the length in the thickness direction including the soft portion in a side view of the grip portion viewed along the width direction is defined as De, the length in the thickness direction of the grip portion in the side view is defined as Dh, the length in the width direction including the soft portion in a front view of the grip portion viewed along the thickness direction is defined as We, and the length in the width direction of the grip portion in the front view is defined as 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.

[0024] The effects of the invention

[0025] In this invention, the toothbrush achieves a fit to the object being cleaned without relying on brushing methods or techniques. Attached Figure Description

[0026] Figure 1 This is a diagram illustrating an embodiment of the present invention, and is a side view showing the structure of the toothbrush 1.

[0027] Figure 2 This is a front view of toothbrush 1 viewed from the bristle-embedded surface 3a.

[0028] Figure 3 This is a side view showing the structure of the hard part 60.

[0029] Figure 4 This is a front view of the hard part 60 as seen from the hair-embedded surface 3a.

[0030] Symbol Explanation

[0031] 1. Toothbrush

[0032] 2. Brush the main body

[0033] 3. Head

[0034] 3a hair transplanting surface

[0035] 4. Neck

[0036] 5. Grip section

[0037] 40 Hair transplantation department

[0038] 60 Hardened part

[0039] 70 Soft part

[0040] Positions A, B, C, and D Detailed Implementation

[0041] The following is for reference Figures 1 to 4 Embodiments of the toothbrush of the present invention will be described.

[0042] Furthermore, the following embodiments illustrate one aspect of the present invention and do not limit the invention; any modifications can be made within the scope of the technical concept of the present invention. Additionally, in the following drawings, for ease of understanding of the structures, the scale, quantities, etc., of each construction differ from the actual construction.

[0043] In the following description, the side of the head 3 with the bristle surface 3a (the side facing the bristle surface) described later will be designated as the front side of the toothbrush 1, and the side of the head 3 opposite to the side facing the bristle surface 3a will be designated as the back side of the toothbrush 1. Furthermore, the direction in which the brush body 2 extends, parallel to the bristle surface 3a and described later, will be designated as the long axis direction; the direction in which the toothbrush 1 is parallel to the bristle surface 3a and orthogonal to the long axis direction will be designated as the width direction; and the direction in which the toothbrush 1 is orthogonal to the bristle surface 3a will be designated as the thickness direction. Additionally, the side with the head 3 in the long axis direction (the head 3 side) will be designated as the front end side, and the side with the grip 5 (the grip 5 side) will be designated as the rear end side.

[0044] Figure 1 This is a diagram showing the structure of toothbrush 1, and it is a side view of toothbrush 1 viewed along the width direction.

[0045] Figure 2 This is a front view of the toothbrush 1 viewed from the side of the bristle-embedded surface 3a in the thickness direction. Furthermore, in... Figure 2 , the illustration of the hair transplantation part 40 is omitted.

[0046] like Figure 1 and Figure 2 As shown, the toothbrush 1 of this embodiment includes a brush body 2, which is formed as an elongated strip and is made of resin molding, and a bristle-embedding part 40.

[0047] The brush body 2 has: a head region 3R located at the front end and having a bristle implantation surface 3a; a grip region 5R disposed at the rear end of the head region 3R; and a neck region 4R disposed between the head region 3R and the grip region 5R. The toothbrush 1 can clean the oral cavity through the bristle implantation section 40 having multiple bristle bundles (not shown) implanted on the bristle implantation surface 3a of the head region 3R.

[0048] The brush body 2 has a hard portion 60 formed of hard resin and a soft portion 70 formed of soft resin. The hard portion 60 extends along its long axis. The hard portion 60 forms at least a portion of the head region 3R, the neck region 4R, and the grip region 5R. The soft portion 70 forms a portion of the grip region 5R.

[0049] The soft part 75 covers a portion of the hard part 60 in the gripping area 5R.

[0050] The rigid part 60 includes: a head 3 located in the head region 3R, a neck 4 located in the neck region 4R, and a gripping part 5 located in the gripping region 5R.

[0051] As an example, as a rigid resin, resins with a flexural modulus (JIS 7171) of 1000 MPa or more and 2800 MPa or less are listed. For example, polypropylene (PP) resin, polyacetal (POM) resin, polybutylene terephthalate (PBT) resin, etc. are preferred in terms of strength.

[0052] In addition, regarding flexibility, a flexural modulus of 1000-2000 MPa is preferred, and PP resin is preferred.

[0053] As a soft resin, a Shore A hardness of 30 or higher and 80 or lower is more preferred. Examples of soft resins include elastomers (e.g., olefin-based elastomers, styrene-based elastomers, polyester-based elastomers, polyurethane-based thermoplastic elastomers, etc.) and silicones.

[0054] (The outline shape of the front and side of the brush body)

[0055] like Figure 1As shown, in the toothbrush 1 of this embodiment, when the brush body 2 is viewed from the side, the outline of the brush body 2 on the front side, from the rear end of the head region 3R toward the gripping region 5R, includes: a first straight region L1 extending in a straight line from the bristle surface 3a of the head region 3R toward the rear end; a first curved region F1 having a center of curvature on the front side, extending in an arc shape from the rear end of the first straight region L1 toward the rear end to a convex vertex 51A; a second curved region F2 having a center of curvature on the front side, extending in an arc shape from the vertex 51A toward the rear end; a third curved region F3 having a center of curvature on the back side, extending from the rear end of the second curved region F2 toward the rear end; a fourth curved region F4 having a center of curvature on the front side, extending from the rear end of the third curved region F3 toward the rear end; and a fifth curved region F5 having a center of curvature on the back side, extending from the rear end of the fourth curved region F4 toward the rear end.

[0056] (The outline shape of the back side of the brush body)

[0057] In the toothbrush 1 of this embodiment, when the brush body 2 is viewed from the side, the outline of the brush body 2 on the back side, from the rear end of the head region 3R toward the grip region 5R, includes: a second straight region L2 extending in a straight line continuously from the back of the head 3 toward the rear end; a sixth curved region F6 having a center of curvature on the front side and extending in an arc shape from the rear end of the second straight region L2 toward the rear end; and a seventh curved region having a center of curvature on the back side and extending in an arc shape from the rear end of the sixth curved region F6 toward the rear end to the apex 51B. Line region F7; eighth curve region F8 having a center of curvature on the back side and extending in an arc shape from vertex 51B to the rear side; ninth curve region F9 having a center of curvature on the front side and extending in an arc shape from the rear end of the eighth curve region F8 to the rear side; tenth curve region F10 having a center of curvature on the back side and extending in an arc shape from the rear end of the ninth curve region F9 to the rear side; and eleventh curve region F11 having a center of curvature on the front side and extending in an arc shape from the rear end of the tenth curve region F10 to the rear side.

[0058] In a side view, the neck region 4R and the gripping region 5R extend obliquely relative to the long axis in the thickness direction toward the front side as they move toward the rear end. The first curved region F1, the second curved region F2, the third curved region F3, the fourth curved region F4, and the fifth curved region F5 are located at the same position as the hair-planting surface 3a in the thickness direction or at a position further toward the front side than the hair-planting surface 3a in the thickness direction.

[0059] (The shape of the outline on both sides of the brush body in the width direction)

[0060] like Figure 2As shown, in the toothbrush 1 of this embodiment, when the brush body 2 is viewed from the front, the outlines of both sides of the brush body 2 in the width direction are linearly symmetrical with respect to the center line located at the center in the width direction and extending along the long axis direction. Therefore, in the following description, the width direction side (in...) Figure 2 The outline of the outer shape (middle and lower sides) will be explained. In addition, regarding the position of the center of curvature of the curved area that extends in an arc shape, the case on the side with the center in the width direction relative to the outer outline is called the inner side, and the case on the side opposite to the center in the width direction is called the outer side.

[0061] In the toothbrush 1 of this embodiment, when the brush body 2 is viewed from the front, the outer contour line in the width direction of the brush body 2 has: a third straight line region L3 extending in a straight line from the boundary between the head region 3R and the neck region 4R (details will be described later) toward the rear end; a twelfth curved region F12 having a center of curvature on the outer side and extending in an arc shape from the rear end of the third straight line region L3 toward the rear end; a thirteenth curved region F13 having a center of curvature on the inner side and extending in an arc shape from the rear end of the twelfth curved region F12 toward the rear end; a fourteenth curved region F14 having a center of curvature on the outer side and extending in an arc shape from the rear end of the thirteenth curved region F13 toward the rear end; and a fifteenth curved region F15 having a center of curvature on the inner side and extending in an arc shape from the rear end of the fourteenth curved region F14 toward the rear end.

[0062] The boundary between head region 3R and neck region 4R is position A at the front end of the third straight line region L3. Furthermore, the boundary between head 3 and neck 4, described later, coincides with position A. The boundary between neck region 4R and gripping region 5R is position B in the front view, where the outline changes from the twelfth curve region F12 with its center on the outside to the thirteenth curve region F13 with its center on the inside. The boundary between neck 4 and gripping part 5, described later, coincides with position B. If the location of the outline change is unclear, it is the position at the very front end where the soft resin begins to cover. The boundary is shared in both front and side views.

[0063] The gripping area 5R is completely covered by the soft portion 74 from position B to the rear end. The hard portion 60 is exposed to the outside in the rear end and the design area 5A on the front side of the gripping area 5R. Except for the rear end and the design area 5A, it is completely covered by the soft portion 75.

[0064] like Figure 2 As shown, the length of the gripping area 5R in the width direction is at its maximum in the thirteenth curve region F13 and the fifteenth curve region F15 in the frontal view, and at its minimum in the fourteenth curve region F14.

[0065] like Figure 1As shown, the thickness direction length of the gripping region 5R, in a side view, decreases from its maximum value between vertices 51A and 51B to its minimum value between the second curve region F2 and the eighth curve region F8. The thickness direction length of the gripping region 5R increases from its minimum value between the second curve region F2 and the eighth curve region F8 to its maximum value between the third curve region F3 and the ninth curve region F9. The thickness direction length of the gripping region 5R decreases from its maximum value between the third curve region F3 and the ninth curve region F9 to its minimum value between the fourth curve region F4 and the tenth curve region F10. The thickness direction length of the gripping region 5R increases from its minimum value between the fourth curve region F4 and the tenth curve region F10 to its maximum value between the fifth curve region F5 and the eleventh curve region F11, and then decreases towards the rear end.

[0066] In the gripping area 5R, the area of ​​the second curved region F2 from the apex 51A towards the rear side and the area of ​​the eighth curved region F8 from the apex 51B towards the front side constitute the finger contact area when the user grips the gripping area 5R.

[0067] Figure 3 This is a side view showing the structure of the hard part 60. Figure 4 This is a front view of the hard part 60 as seen from the hair-embedded surface 3a.

[0068] like Figure 3 and Figure 4 As shown, the rigid part 60 has: a head 3; a gripping part 5 located on the rear end side in the long axis direction of the head 3; and a neck 4 located between the head 3 and the gripping part 5.

[0069] (Head 3)

[0070] Head 3 is the part that brushes the inside of the mouth using multiple bristle tufts, such as... Figure 4 As shown, it forms a roughly rectangular parallelepiped shape with rounded corners. The head 3 has a roughly quadrilateral flat shape with four curved chamfered corners at the top in a frontal view. In this embodiment, the boundary between the head 3 and the neck 4 is the endpoint of the curve forming the chamfer on the side of the neck 4 in the frontal view shape of the head 3, that is, the position A where the curvature direction of the curve forming the chamfer changes.

[0071] The head 3 has a hair-implanting surface 3a on the front side. Multiple hair-implanting holes 6 are arranged on the hair-implanting surface 3a. The shape and diameter of the hair-implanting holes 6 are not particularly limited. Hair bundles constituting the hair-implanting section 40 are implanted into each of the hair-implanting holes 6.

[0072] The head 3 is not covered by the soft part 70. That is, the head 3 is completely exposed. The head region 3R is composed of the head 3.

[0073] By bundling and folding multiple bristles (monofilaments), sandwiching a metal anti-loosening element (not shown) called a flat wire between them, and inserting it into the bristle implantation hole 6, the bristle bundle is implanted into each bristle implantation hole 6. The shape of the head 3 is not particularly limited; for example, the bristle implantation surface 3a on the front side and the surface on the back side are formed to be flat and parallel to each other.

[0074] The head 3 can be any shape and size that facilitates brushing inside the mouth, and its shape is not particularly limited. For example, it can be a shape in which the width gradually narrows from the base side to the front side. Alternatively, the head 3 can be a cone shape in which the thickness gradually thins from the base side to the front side, or it can be a shape with rounded corners that is raised in the center of the dorsal side of the head 3.

[0075] The width of the head 3 is not particularly limited, but is preferably 7 mm or more and 16 mm or less. If it is above the lower limit, the area for implanting hair tufts can be sufficiently ensured, and if it is below the upper limit, the operability in the oral cavity can be further improved.

[0076] Furthermore, if the head 3 is a wide type with a width of 12mm or more, it is easy to apply a torsional force to the head 3 when performing cleaning based on the Rosberg rotary brushing method / Bass brushing method described later.

[0077] The length of the head 3 along its major axis is not particularly limited, but is preferably 10 mm or more and 33 mm or less. If the length of the head 3 is above the lower limit mentioned above, the area for implanting hair tufts can be sufficiently ensured, and if it is below the upper limit mentioned above, the operability within the oral cavity can be further improved.

[0078] The thinner the length of the head 3 in the thickness direction, the better the operability within the oral cavity; however, if it is too thin, the strength of the head 3 may become insufficient. Therefore, as an example, the length of the head 3 in the thickness direction is set in the range of 2.5 mm or more and 4.5 mm or less. More preferably, the length of the head 3 in the thickness direction is 2.5 mm or more and 4.0 mm or less. Even more preferably, the length of the head 3 in the thickness direction is 2.5 mm or more and 3.7 mm or less.

[0079] The lower limit of the length of the head 3 in the thickness direction is preferably 2.5 mm or more.

[0080] The upper limit of the length of the head 3 in the thickness direction is preferably 4.5 mm or less, more preferably 4.0 mm or less, and even more preferably 3.7 mm or less.

[0081] (Neck 4)

[0082] The neck 4 is the part located between the grip 5 and the head 3 and connects the grip 5 and the head 3.

[0083] The length of the neck 4 in the major axis direction is preferably 35.0 mm or more and 50.0 mm or less, more preferably 37.0 mm or more and 48.0 mm or less.

[0084] The lower limit of the length of the neck 4 in the major axis direction is preferably 36.0 mm or more, and more preferably 37.0 mm or more.

[0085] The upper limit of the length of the neck 4 in the long axis direction is preferably 50.0 mm or less, more preferably 48.0 mm or less.

[0086] The length of the neck 4 in both the thickness and width directions is constant or gradually increases in diameter from the front end to the rear end.

[0087] Figure 2 In the frontal view, the outline of the front end of the neck 4 adopts a fixed width formed by the third straight line region L3.

[0088] The length of the major axis of the third straight region L3 is preferably 18.0 mm or more and 35.0 mm or less, more preferably 20.0 mm or more and 30.0 mm or less.

[0089] The lower limit of the length of the major axis of the third straight region L3 is preferably 18.0 mm or more, and more preferably 20.0 mm or more.

[0090] The upper limit of the length of the major axis of the third straight region L3 is preferably 35.0 mm or less, and more preferably 30.0 mm or less.

[0091] In a frontal view, the rearward profile of the third straight region L3 of the neck 4 is formed by the twelfth curved region F12. Within the neck 4 formed by the twelfth curved region F12, the length in the width direction gradually increases towards the rearward side until position B at the rearward end. That is, the length in the width direction of the neck 4 is maximum at position B. Position B is the boundary between the neck 4 and the gripping part 5.

[0092] In a side view, the frontal profile of the neck 4 is formed by the first curved region F1. The frontal profile of the neck 4 gradually extends towards the frontal side as it moves toward the rear end. The rearal profile of the neck 4 is formed by the sixth curved region F6. The rearal profile of the neck 4 gradually extends towards the frontal side as it moves toward the rear end. The length of the first curved region F1 towards the frontal side as it moves toward the rear end is greater than the length of the sixth curved region F6 towards the frontal side as it moves toward the rear end. Therefore, the length of the neck 4 in the thickness direction increases as it moves toward the rear end.

[0093] Furthermore, the outline of the front side of the neck 4 may not be formed from the first curved region F1 or the sixth curved region F6 starting from position A, but may instead be connected to the first curved region F1 or the sixth curved region F6 via a straight region. In this case, the length of the straight region is preferably 15.0 mm or less.

[0094] (Holding part 5)

[0095] like Figure 3 As shown, in a side view, the grip portion 5 extends from position C at the front end towards the rear end, and then towards the front. Position C is the same position or approximately the same position as position B at the rear end of the neck 4. Furthermore, "approximately the same position" is defined as the case where position C is located within a distance of 0.2 mm from position B to the rear end in the long axis direction.

[0096] There exists a region at position C where the length of the grip portion 5 in the thickness direction is shorter than the length of the neck 4 in the thickness direction. The length of the grip portion 5 in the thickness direction temporarily increases from position C toward the rear end side by an dimension shorter than the length of the rear end side of the neck 4 in the thickness direction, then decreases, and then extends approximately constantly. The grip portion 5 has a protrusion 5B protruding toward the front side at a position in the design region 5A in the long axis direction. The end face of the front side of the protrusion 5B is exposed in the grip region 5R. A protrusion 5C is provided at the rear end of the grip portion 5, which is exposed at the rear end of the grip region 5R.

[0097] The length of the grip portion 5 in the width direction is preferably 4.5 mm or more and 14.0 mm or less over the entire area of ​​the grip portion 5, and more preferably 4.5 mm or more and 12.0 mm or less.

[0098] The lower limit of the length of the grip portion 5 in the width direction is preferably 4.5 mm or more.

[0099] The upper limit of the length of the grip portion 5 in the width direction is preferably 14.0 mm or less, and more preferably 12.0 mm or less.

[0100] The length of the grip portion 5 in the thickness direction is preferably 4.5 mm or more and 18.0 mm or less in the entire area of ​​the grip portion 5, and more preferably 4.5 mm or more and 16.0 mm or less.

[0101] The lower limit of the length of the grip portion 5 in the thickness direction is preferably 4.5 mm or more.

[0102] The upper limit of the length of the grip portion 5 in the thickness direction is preferably 18.0 mm or less, and more preferably 16.0 mm or less.

[0103] The length of the grip portion 5 in the long axis direction is preferably 80 mm or more and 140 mm or less, more preferably 90 mm or more and 130 mm or less.

[0104] The lower limit of the length of the grip portion 5 in the long axis direction is preferably 90 mm or more.

[0105] The upper limit of the length of the grip portion 5 in the long axis direction is preferably 140 mm or less, and more preferably 130 mm or less.

[0106] This range is inclusive. Figure 3 and Figure 4 The range of the protrusions 5B and 5C. In addition, as described later, the gripping part 5 has a portion in a continuous region with a length in both the thickness direction and the width direction of 4.5 mm or more and 8.0 mm or less.

[0107] (Location A of the boundary between head 3 and neck 4)

[0108] The length in both the thickness and width directions of the neck 4 at position A is 3.0 mm or more and 4.3 mm or less. When the length in both the thickness and width directions of the neck 4 at position A is less than 3.0 mm, the neck 4 excessively flexes and becomes excessively movable. If the length in both the thickness and width directions of the neck 4 at position A exceeds 4.3 mm, sufficient flexing cannot be achieved. By setting the length in both the thickness and width directions of the neck 4 at position A to 3.0 mm or more and 4.3 mm or less, moderate flexing can be achieved. More preferably, the length in both the thickness and width directions of the neck 4 at position A is set to 3.0 mm or more and 4.0 mm or less.

[0109] The ratio of the length of the neck 4 in the width direction at position A to the length of the neck 4 in the width direction at position B is preferably 0.30 or more and 0.60 or less, more preferably 0.40 or more and 0.50 or less.

[0110] The lower limit of the ratio of the length of the neck 4 in the width direction at position A to the length of the neck 4 in the width direction at position B is preferably 0.30 or more, and more preferably 0.40 or more.

[0111] The upper limit of the ratio of the length of the neck 4 in the width direction at position A to the length of the neck 4 in the width direction at position B is preferably 0.60 or less, more preferably 0.50 or less.

[0112] The ratio of the length of the neck 4 in the thickness direction at position A to the length of the neck 4 in the thickness direction at position B is preferably 0.30 or more and 0.60 or less, more preferably 0.40 or more and 0.50 or less.

[0113] The lower limit of the ratio of the length of the neck 4 in the thickness direction at position A to the length of the neck 4 in the thickness direction at position B is preferably 0.30 or more, and more preferably 0.40 or more.

[0114] The upper limit of the ratio of the length of the neck 4 in the thickness direction at position A to the length of the neck 4 in the thickness direction at position B is preferably 0.60 or less, more preferably 0.50 or less.

[0115] If the ratio of the width length of the neck 4 at position A to the width length of the neck 4 at position B, or the ratio of the thickness length of the neck 4 at position A to the thickness length of the neck 4 at position B, is less than 0.30, the front end is too thin, causing stress concentration at the front end, resulting in only the front end of the neck 4 deflecting and preventing overall deflection of the neck 4. Alternatively, the rear end is too thick and does not coordinate with the grip portion 5, resulting in only the neck 4 deflecting. On the other hand, if the ratio of the width length or the thickness length exceeds 0.60, the rear end of the neck 4 becomes thinner and does not coordinate with the grip portion 5, resulting in excessive overall deflection of the neck 4. Alternatively, the front end of the neck 4 becomes thicker, making it difficult for the front end of the neck 4 to deflect. Therefore, by setting the ratio of the width length and the thickness length to 0.30 or more and 0.60 or less, overall deflection of the neck 4 can be achieved in conjunction with the grip portion 5. More preferably, the ratio of the width length and the thickness length is 0.40 or more and 0.50 or less.

[0116] For the brush body 2 (toothbrush 1) described above, a position is fixed at 40% of the length of the long axis of the grip portion 5 from the front end (position C) to the rear end. When a load of 200g is applied along the width direction or along the thickness direction at the central position of the bristle portion 40 in the long axis direction, at least one of the bending in the width direction and the bending in the thickness direction bends from the grip portion 5. That is, in the brush body 2, when the above-mentioned load is applied to the above-mentioned position, in at least one of the width direction and the thickness direction, only the neck 4 does not bend, but bends from the grip portion 5.

[0117] The following sections will explain in detail the methods for determining the starting point and bending length of the brush body 2 in the width and thickness directions, respectively.

[0118] (The starting point and bending length of the brush body 2 in the width direction)

[0119] The starting point and bending length of the brush body 2 in the width direction are determined by the following method (α).

[0120] Method (α):

[0121] For a position that is 40% of the length of the long axis of the grip from the front end to the rear end, the height of the front end of the brush body 2 in the fixed state is set as the reference height. In the fixed state, a load of 200g is applied to the center position of the bristle section in the long axis of the head along the width direction. The starting position of the bending in the width direction is measured after 10 seconds, and the displacement of the front end of the brush body 2 relative to the reference height in the width direction (in mm) is measured as the bending length.

[0122] Specifically, in this embodiment, the starting position and bending length of the brush body 2 in the width direction are determined as follows.

[0123] like Figure 2 As shown, for the brush body 2, the gripping part 5 is fixed using a clamp 100 with the width direction aligned vertically. The clamp 100 fixes the gripping part 5 at a position P1, which is 40% of the length of the gripping part 5 along its long axis, from the front end (position C) to the rear end. At this time, the height of the front end of the brush body 2 is set as the reference height H0.

[0124] Next, a 200g weight 102 is suspended at position S, and the starting point of the bending of the brush body 2 and the height H1 of the front end of the brush body 2 are measured after 10 seconds. Position S is the center position of the bristle implantation section 40 in the head 3 along its long axis. The center position of the bristle implantation section 40 along its long axis represents the center position between the outer edge of the foremost side and the outer edge of the rearmost side in the long axis direction among the outer edges of the multiple bristle implantation holes 6.

[0125] Then, calculate the displacement from height H0 to height H1 (in mm).

[0126] The above measurements were performed five times, and the average value of the displacement was taken as the bending length in the width direction of the brush body 2.

[0127] (The starting point and bending length of the brush body 2 in the thickness direction)

[0128] The starting point and bending length of the brush body 2 in the thickness direction are determined by the following method (β).

[0129] Method (β):

[0130] For a position that is 40% of the length of the long axis of the grip from the front end to the rear end, the height of the front end of the brush body 2 in the fixed state is set as the reference height. In the fixed state, a load of 200g is applied to the center position of the bristle section in the long axis of the head along the width direction. The starting position of the bending in the thickness direction is measured after 10 seconds, and the displacement of the front end of the brush body 2 relative to the reference height in the thickness direction (in mm) is measured as the bending length.

[0131] Specifically, in this embodiment, the starting point position and bending length of the brush body 2 in the thickness direction are determined as follows.

[0132] like Figure 1 As shown, for the brush body 2, the gripping part 5 is fixed using a clamp 100 with the thickness direction being vertical. The clamp 100 fixes the gripping part 5 at a position P1, which is 40% of the length of the gripping part 5 along its long axis, from the front end (position C) to the rear end. At this time, the height of the front end of the brush body 2 is set as the reference height H0.

[0133] Next, a 200g weight 102 is suspended at the aforementioned position S, and the starting point of the bending of the brush body 2 and the height H2 of the front end of the brush body 2 are measured after 10 seconds.

[0134] Furthermore, calculate the displacement (in mm) from height H0 to height H2.

[0135] The above measurements were performed five times, and the average value of the displacement was taken as the bending length in the thickness direction of the brush body 2.

[0136] If, in either the width or thickness direction, the neck 4 is thicker at position A, and the ratio of the length of the neck 4 at position A to the length of the neck 4 at position B exceeds 0.60, then deflection at the front end of the neck 4 is impossible. Conversely, if, in either the width or thickness direction, the neck 4 is thicker at position B, and the ratio of the length of the neck 4 at position A to the length of the neck 4 at position B is less than 0.30, then deflection at the rear end of the neck 4 is impossible. In particular, if the neck 4 is excessively thick at position B relative to position A, stress is applied only to the front end of the neck 4, and deflection in either the width or thickness direction is impossible at the rear end of the neck 4. Furthermore, if the grip portion 5 is thicker than the neck 4, deflection originating from the grip portion 5 is impossible, and a larger movable area cannot be obtained.

[0137] Therefore, by setting the ratio of the length of the neck 4 at position A to the length of the neck 4 at position B to 0.30 or more and 0.60 or less in both the width and thickness directions, the head 3, neck 4 and grip 5 in the brush body 2 can bend from the grip 5 with a larger movable area in the width or thickness direction when the load is applied to the above-mentioned position.

[0138] The maximum bending length (maximum deflection) of the front end of the brush body 2 10 seconds after the above-mentioned load is applied is independent of the starting position of the bending of the brush body 2. It is preferably 6.0 mm or more and 11.0 mm or less when the load is applied in the width direction and when the load is applied in the thickness direction, and more preferably 7.0 mm or more and 10.0 mm or less.

[0139] The lower limit of the maximum bending length (maximum deflection) of the front end of the brush body 2 10 seconds after the above-mentioned load is applied is preferably 6.0 mm or more, and more preferably 7.0 mm or more.

[0140] The upper limit of the maximum bending length (maximum deflection) of the front end of the brush body 2 10 seconds after the above-mentioned load is applied is preferably 11.0 mm or less, more preferably 10.0 mm or less.

[0141] When the bending length is less than 6.0 mm, the user does not feel sufficient deflection; when the bending length exceeds 11.0 mm, the deflection is excessive, reducing operability. By making the bending length between 6.0 mm and 11.0 mm, sufficient deflection can be achieved in both the width and thickness directions without reducing operability. Therefore, in the toothbrush 1 of this embodiment, the head 3 is easily movable, thereby improving the fit during brushing, especially effective when the brushing method is the fones brushing technique.

[0142] Furthermore, in the brush body 2, the front and back sides of the brush body 5 are fixed within a range of 9 mm from the front end of the gripping part 5 to the rear end of the gripping part, and the front, back, and side sides of the brush body 3 are fixed within a range from the front end of the brush body 3 to the center position of the long axis of the bristle section. In this state, when the brush body 3 is rotated about the axis extending along the long axis with a force of 20 N·cm, the rotation angle of the brush body 3 is preferably 30° or more and 50° or less, more preferably 40° or more and 50° or less.

[0143] The lower limit of the aforementioned rotation angle is preferably 30° or more, and more preferably 40° or more.

[0144] The upper limit of the aforementioned rotation angle is preferably below 50°.

[0145] When the rotation angle of the head 3 when the aforementioned force is applied is less than 30°, the movable area of ​​the head 3 in the rotation direction centered on the axis extending along the long axis direction during cleaning becomes narrow. When the rotation angle of the head 3 when the aforementioned force is applied exceeds 50°, the head 3 during cleaning twists excessively in the rotation direction centered on the axis extending along the long axis direction, making it impossible to achieve stable contact. By making the rotation angle of the head 3 when the aforementioned force is applied between 30° and 50°, sufficient twisting of the head 3 can be ensured during cleaning. Therefore, in the toothbrush 1 of this embodiment, the bristles can contact the teeth at various angles during cleaning, and contact is easily achieved, especially during the Robowski rotary brushing method and the Bass brushing method.

[0146] In the following description, the length in the thickness direction of the hardened portion 60 is defined as D mm, and the length in the width direction is defined as W mm. Furthermore, if W × D at position A of the neck 4 is... 3 The value represented is set as WD. 3 (A)mm 4 W×D at position B 3 The value represented is set as WD. 3 (B)mm 4 WD 3 (B) Preferably 1200mm 4 Above and 6500mm 4 Below, 2400mm is preferred. 4 Above and 5200mm 4 the following.

[0147] WD 3 (B) The lower limit is preferably 1200 mm. 4 The above is preferred, with 2400mm being even better. 4 above.

[0148] WD 3 (B) The upper limit is preferably 6500 mm 4 Below, 5200mm is preferred. 4 the following.

[0149] WD 3 (A), WD 3 The value represented by (B) indicates the value of the second moment of the cross section at positions A and B when the cross section of the neck 4 is approximately rectangular and a load is applied in the thickness direction. It is related to the deflection ease of the neck 4 in the thickness direction.

[0150] In WD 3 (B) Less than 1200mm 4 In cases where the bending transition in the thickness direction exceeds 6500mm 4In this case, sufficient deflection cannot be obtained in the thickness direction. By making WD 3 (B) is 1200mm 4 Above and 6500mm 4 The following allows for sufficient flexural bending in the thickness direction of the neck 4 without excessive bending.

[0151] WD 3 (A) / WD 3 The value represented by (B) is preferably 0.01 or more and 0.20 or less, more preferably 0.03 or more and 0.06 or less.

[0152] WD 3 (A) / WD 3 The lower limit of the value represented by (B) is preferably 0.01 or more, and more preferably 0.03 or more.

[0153] WD 3 (A) / WD 3 The upper limit of the value represented by (B) is preferably 0.20 or less, more preferably 0.06 or less.

[0154] In order to make WD 3 (A) / WD 3 (B) Implementation as described above, WD 3 (A) Preferably 80mm 4 Above and 350mm 4 The following is preferred to be 80mm 4 Above and 260mm 4 the following.

[0155] WD 3 (A) The lower limit is preferably 80 mm. 4 above.

[0156] WD 3 (A) is preferably 350 mm. 4 The following is a preferred size: 260mm 4 the following.

[0157] In WD 3 (A) / WD 3 When the value represented by (B) is less than 0.01, the deflection in the thickness direction of the front end of the neck 4 becomes greater, making it impossible for the entire grip portion 5 to deflect in the thickness direction. Alternatively, the rear end of the neck 4 is too thick and does not coordinate with the grip portion 5, resulting in only the neck 4 deflecting. (WD) 3 (A) / WD 3(B) When the value exceeds 0.20, sufficient deflection in the thickness direction cannot be achieved at the front end of the neck 4. Alternatively, the rear end of the neck 4 tapers and does not interact with the grip portion 5, resulting in excessive deflection of the entire neck 4. By making WD 3 (A) / WD 3 (B) indicates a value of 0.01 or higher and 0.20 or lower, which enables the gripping part 5 to flex in the thickness direction.

[0158] Additionally, if we consider the D×W at position A... 3 The value represented is set as DW. 3 (A)mm 4 D×W at position B 3 The value represented is set as DW. 3 (B)mm 4 Then DW 3 (B) Preferably 1200mm 4 Above and 6500mm 4 Below, 2400mm is preferred. 4 Above and 5200mm 4 the following.

[0159] DW 3 (B) The lower limit is preferably 1200 mm. 4 The above is preferred, with 2400mm being even better. 4 above.

[0160] DW 3 (B) The upper limit is preferably 6500 mm 4 Below, 5200mm is preferred. 4 the following.

[0161] DW 3 (A) DW 3 The value represented by (B) indicates the value of the second moment of the cross section at positions A and B when the cross section of the neck 4 is approximately rectangular and a load is applied in the width direction. It is related to the deflection ease of the neck 4 in the width direction.

[0162] In DW 3 (B) Less than 1200mm 4 In cases where the bending transition in the width direction exceeds 6500mm 4 In this case, sufficient deflection cannot be obtained in the width direction. By making DW 3 (B) is 1200mm 4 Above and 6500mm 4 The neck 4 can be sufficiently flexed in the width direction without being excessive.

[0163] DW 3 (A) / DW 3 The value represented by (B) is preferably 0.01 or more and 0.20 or less, more preferably 0.03 or more and 0.06 or less.

[0164] DW 3 (A) / DW 3 The lower limit of the value represented by (B) is preferably 0.01 or more, and more preferably 0.03 or more.

[0165] DW 3 (A) / DW 3 The upper limit of the value represented by (B) is preferably 0.20 or less, more preferably 0.06 or less.

[0166] In order to make DW 3 (A) / DW 3 (B) Implemented as the above value, DW 3 (A) Preferably 80mm 4 Above and 350mm 4 The following is preferred to be 80mm 4 Above and 260mm 4 the following.

[0167] DW 3 (A) The lower limit is preferably 80 mm. 4 above.

[0168] DW 3 (A) is preferably 350 mm. 4 The following is a preferred size: 260mm 4 the following.

[0169] In DW 3 (A) / DW 3 When the value represented by (B) is less than 0.01, the deflection in the width direction of the front end of the neck 4 becomes too large, making it impossible for the entire gripping part 5 to deflect in the width direction. Alternatively, the rear end of the neck 4 is too thick and does not coordinate with the gripping part 5, resulting in only the neck 4 deflecting. In DW 3 (A) / DW 3 (B) When the value exceeds 0.20, sufficient deflection in the width direction cannot be achieved at the front end of the neck 4. Alternatively, the rear end of the neck 4 tapers and does not coordinate with the grip 5, resulting in excessive deflection of the entire neck 4. By making DW 3 (A) / DW 3 (B) indicates a value of 0.01 or higher and 0.20 or lower, which enables the gripping part 5 to flex in the width direction.

[0170] like Figure 3 and Figure 4As shown, if position H is defined as 10mm from position B towards the front end, the width length of the neck 4 at position H is preferably 3.0mm or more and 4.5mm or less. The thickness length of the neck 4 at position H is preferably 5.0mm or more and 6.5mm or less. The ratio D / W(H), which represents the thickness length of the neck 4 at position H to its width length, is preferably 1.3 or more and 1.7 or less. If W×D at position H of the neck 4... 3 The value represented is set as WD. 3 (H)mm 4 D×W 3 The value represented is set as DW. 3 (H)mm 4 WD 3 (H) is preferably 350mm 4 Above and 1300mm 4 Below, 500mm is preferred. 4 Above and 1000mm 4 the following.

[0171] WD 3 The lower limit of (H) is preferably 350 mm. 4 The above, preferably 500mm 4 above.

[0172] WD 3 The upper limit of (H) is preferably 1300 mm. 4 Hereinafter, 1000mm is preferred. 4 the following.

[0173] DW 3 (H) is preferably 130mm 4 Above and 600mm 4 Below, 200mm is preferred. 4 Above and 500mm 4 the following.

[0174] DW 3 The lower limit of (H) is preferably 130 mm. 4 The above, preferably 200mm 4 above.

[0175] DW 3 The upper limit of (H) is preferably 600 mm. 4 Below, 500mm is preferred. 4 the following.

[0176] If position G is defined as 20mm from position B towards the front end, then the length of the neck 4 at position G in the width direction is preferably 3.0mm or more and 4.5mm or less. The length of the neck 4 at position G in the thickness direction is preferably 4.0mm or more and 5.5mm or less. The ratio D / W(G), which represents the length of the neck 4 in the thickness direction to its length in the width direction, is preferably 1.1 or more and 1.5 or less. If W×D at position G of the neck 4... 3 The value represented is set as WD. 3 (G)mm 4 D×W 3 The value represented is set as DW. 3 (G)mm 4 WD 3 (G) Preferably 200mm 4 Above and 750mm 4 Below, 300mm is preferred. 4 Above and 600mm 4 the following.

[0177] WD 3 The lower limit of (G) is preferably 200 mm. 4 The above, preferably 300mm 4 above.

[0178] WD 3 The upper limit of (G) is preferably 750 mm. 4 The following is more preferably 600mm 4 the following.

[0179] DW 3 (G) is preferably 100mm 4 Above and 500mm 4 The following is more preferably 150mm 4 Above and 400mm 4 the following.

[0180] DW 3 The lower limit of (G) is preferably 100 mm. 4 The above is preferred, with 150mm being more ideal. 4 above.

[0181] DW 3 The upper limit of (G) is preferably 500 mm. 4 Below, 400mm is preferred. 4 the following.

[0182] If position F is defined as 30mm from position B towards the front end, then the length of the neck 4 at position F in the width direction is preferably 3.0mm or more and 4.5mm or less. The length of the neck 4 at position F in the thickness direction is preferably 3.5mm or more and 4.5mm or less. The ratio D / W(F), which represents the length of the neck 4 in the thickness direction to its length in the width direction, is preferably 0.90 or more and 1.3 or less. If W×D at position F of the neck 4... 3 The value represented is set as WD. 3 (F)mm 4 D×W 3 The value represented is set as DW. 3 (F)mm 4 WD 3 (F) is preferably 100mm 4 Above and 400mm 4 The following is more preferably 150mm 4 Above and 300mm 4 the following.

[0183] WD 3 The lower limit of (F) is preferably 100 mm. 4 The above is preferred, with 150mm being more ideal. 4 above.

[0184] WD 3 The upper limit of (F) is preferably 400 mm. 4 Below, 300mm is preferred. 4 the following.

[0185] DW 3 (F) is preferably 90mm 4 Above and 400mm 4 The following is a preferred size: 130mm 4 Above and 300mm 4 the following.

[0186] DW 3 The lower limit of (F) is preferably 90 mm. 4 The above is preferred, with 130mm being even better. 4 above.

[0187] DW 3 The upper limit of (F) is preferably 400 mm. 4 Below, 300mm is preferred. 4 the following.

[0188] Preferably, in any position, the length of the grip portion 5 in both the thickness direction and the width direction is 4.5 mm or more and 8.0 mm or less in a continuous region of at least 20% of the length of the grip portion 5 in the long axis direction. More preferably, the length of the grip portion 5 in both the thickness direction and the width direction is 4.5 mm or more and 8.0 mm or less in a continuous region of at least 50% of the length of the grip portion 5 in the long axis direction.

[0189] 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, sufficient deflection of the grip portion 5 cannot be generated. By ensuring that, at any position, in a region representing at least 20% of the length in the long axis direction of the grip portion 5, both the length in the thickness direction and the length in the width direction are 4.5 mm or more and 8.0 mm or less, sufficient deflection of the grip portion 5 can be prevented from occurring excessively.

[0190] If we define C as the position of the front end of the grip portion 5 along its long axis, and define D as the position 50% of the length of the grip portion 5 along its long axis from the front end to the rear end, then preferably, the length of the grip portion 5 at position C in both the width and thickness directions is 4.5 mm or more and 8.0 mm or less. Similarly, preferably, the length of the grip portion 5 at position D in both the width and thickness directions is 4.5 mm or more and 8.0 mm or less.

[0191] If the W×D at position C of the gripping part 5 is... 3 The value represented is set as WD. 3 (C)mm 4 W×D at position D 3 The value represented is set as WD. 3 (D)mm 4 WD 3 (C) Preferably 410mm 4 Above and 4000mm 4 The following is more preferably 600mm 4 Above and 1800mm 4 the following.

[0192] WD 3 (C) The lower limit is preferably 410 mm. 4 The above, preferably 600mm 4 above.

[0193] WD 3 (C) is preferably 4000 mm. 4 The preferred value is 1800mm. 4 the following.

[0194] WD 3 (C), WD 3 The value represented by (D) indicates the value of the second moment of the cross section at positions C and D when the cross section of the gripping part 5 is approximately rectangular and a load is applied in the thickness direction. It is related to the deflection ease of the gripping part 5 in the thickness direction.

[0195] In WD 3 (C) Less than 410mm 4 In cases where the bending transition in the thickness direction exceeds 4000 mm 4 In this case, sufficient deflection cannot be obtained in the thickness direction. By making WD 3 (C) is 410mm 4 Above and 4000mm 4 Therefore, sufficient flexing can be achieved in the thickness direction of the gripping part 5 without excessive bending.

[0196] WD 3 (C) / WD 3 The value represented by (D) is preferably 0.35 or more and 2.0 or less, more preferably 0.50 or more and 1.5 or less.

[0197] WD 3 (C) / WD 3 The lower limit of the value represented by (D) is preferably 0.35 or more, and more preferably 0.50 or more.

[0198] WD 3 (C) / WD 3 The upper limit of the value represented by (D) is preferably 2.0 or less, more preferably 1.5 or less.

[0199] In order to make WD 3 (C) / WD 3 (D) is implemented as the value described above, WD 3 (D) Preferably 410mm 4 Above and 4000mm 4 The following is more preferably 600mm 4 Above and 2400mm 4 the following.

[0200] WD 3 (D) The lower limit is preferably 410 mm. 4 The above, preferably 600mm 4 above.

[0201] WD 3 The upper limit of (D) is preferably 4000 mm. 4Below, 2400mm is preferred. 4 the following.

[0202] In WD 3 (C) / WD 3 When the value represented by (D) is less than 0.35, the deflection in the thickness direction of the front end of the grip portion 5 becomes large, making it impossible to achieve overall deflection of the grip portion 5 in the thickness direction. Alternatively, the position D of the grip portion 5 is too thick, making it impossible to achieve a thinner grip portion 5. (WD) 3 (C) / WD 3 When the value represented by (D) exceeds 2.0, a finer grip portion 5 cannot be achieved. Alternatively, the deflection in the thickness direction of the tip of the grip portion 5 becomes too large, making it impossible to achieve overall deflection of the grip portion 5 in the thickness direction. By making WD... 3 (C) / WD 3 (D) represents a value of 0.35 or higher and 2.0 or lower, which can achieve both the overall flexibility of the grip portion 5 in the thickness direction and a finer grip portion 5.

[0203] Additionally, if we consider the D×W at position C... 3 The value represented is set as DW. 3 (C)mm 4 , D×W at position D 3 The value represented is set as DW. 3 (D)mm 4 Then DW 3 (C) Preferably 410mm 4 Above and 4000mm 4 The following is more preferably 600mm 4 Above and 1800mm 4 the following.

[0204] DW 3 (C) The lower limit is preferably 410 mm. 4 The above, preferably 600mm 4 above.

[0205] DW 3 (C) is preferably 4000 mm. 4 The preferred value is 1800mm. 4 the following.

[0206] DW 3 (C), DW 3 The value represented by (D) indicates the value of the second moment of the cross section at positions C and D when the cross section of the gripping part 5 is approximately rectangular and a load is applied in the width direction. It is related to the deflection ease of the gripping part 5 in the width direction.

[0207] In DW3 (C) Less than 410mm 4 In the case of excessive deflection in the width direction, exceeding 4000mm 4 In this case, sufficient deflection cannot be obtained in the width direction. By making DW 3 (C) is 410mm 4 Above and 4000mm 4 Therefore, sufficient deflection of the gripping part 5 can be achieved in the width direction without excessive bending.

[0208] DW 3 (C) / DW 3 The value represented by (D) is preferably 0.35 or more and 2.0 or less, more preferably 0.50 or more and 1.5 or less.

[0209] DW 3 (C) / DW 3 The lower limit of the value represented by (D) is preferably 0.35 or more, and more preferably 0.50 or more.

[0210] DW 3 (C) / DW 3 The upper limit of the value represented by (D) is preferably 2.0 or less, more preferably 1.5 or less.

[0211] In order to make DW 3 (C) / DW 3 (D) is implemented as the value described above, DW 3 (D) Preferably 410mm 4 Above and 4000mm 4 The following is more preferably 600mm 4 Above and 2400mm 4 the following.

[0212] DW 3 (D) The lower limit is preferably 410 mm. 4 The above, preferably 600mm 4 above.

[0213] DW 3 The upper limit of (D) is preferably 4000 mm. 4 Below, 2400mm is preferred. 4 the following.

[0214] In DW 3 (C) / DW 3 When the value represented by (D) is less than 0.35, the deflection in the width direction of the front end of the gripping part 5 becomes large, making it impossible to achieve overall deflection in the width direction of the gripping part 5. Alternatively, the position D of the gripping part 5 is too thick, making it impossible to achieve a thinner gripping part 5. In DW3 (C) / DW 3 When the value represented by (D) exceeds 2.0, a finer grip portion 5 cannot be achieved. Alternatively, the deflection in the width direction of the front end of the grip portion 5 becomes too large, making it impossible to achieve overall deflection of the grip portion 5 in the width direction. By making DW... 3 (C) / DW 3 (D) represents a value of 0.35 or higher and 2.0 or lower, which can achieve both the overall flexibility of the gripping part 5 in the width direction and a thinner gripping part 5.

[0215] The ratio of the length of the grip portion 5 in the width direction at position C to the length of the grip portion 5 in the width direction at position D is preferably 0.65 or more and 1.3 or less, more preferably 0.70 or more and 1.2 or less.

[0216] The lower limit of the above ratio is preferably 0.65 or more, and more preferably 0.70 or more.

[0217] The upper limit of the above ratio is preferably 1.3 or less, and more preferably 1.2 or less.

[0218] The ratio of the length of the grip portion 5 in the thickness direction at position C to the length of the grip portion 5 in the thickness direction at position D is preferably 0.65 or more and 1.30 or less, more preferably 0.70 or more and 1.2 or less.

[0219] If the ratio of the width length of the grip portion 5 at position C to the width length of the grip portion 5 at position D, or the ratio of the thickness length of the grip portion 5 at position C to the thickness length of the grip portion 5 at position D, is less than 0.65, then compared to position D, position C has a thinner shape, and stress concentrates at position C, thus preventing the grip portion 5 from flexing as a whole. Alternatively, compared to position C, position D has a thicker shape, making it impossible for the grip portion 5 to flex as a whole. On the other hand, if the ratio of the width length or the thickness length exceeds 1.30, stress concentrates at position D, and flexing at position C does not occur. Compared to position D, position C has a thicker shape, making it impossible for the grip portion 5 to flex as a whole. Therefore, by making the ratio of the width length and the thickness length between 0.65 and 1.30, the grip portion 5 becomes uniform, allowing stress to be dispersed and the grip portion 5 to flex as a whole when force is applied.

[0220] The ratio of the length of the neck 4 in the width direction at position A to the length of the grip portion 5 in the width direction at position D is preferably 0.38 or more and 0.89 or less, more preferably 0.41 or more and 0.54 or less.

[0221] The lower limit of the above-mentioned ratio is preferably 0.38 or more, more preferably 0.41 or more. The upper limit of the above-mentioned ratio is preferably 0.89 or less, more preferably 0.54 or less.

[0222] The ratio of the length of the neck 4 in the thickness direction at position A to the length of the grip portion 5 in the thickness direction at position D is preferably 0.38 or more and 0.89 or less, more preferably 0.54 or more and 0.70 or less.

[0223] The lower limit of the above-mentioned ratio is preferably 0.38 or more, more preferably 0.54 or more. The upper limit of the above-mentioned ratio is preferably 0.89 or less, more preferably 0.70 or less.

[0224] WD 3 (A) / WD 3 The value represented by (D) is preferably 0.10 or higher and 0.20 or lower. DW 3 (A) / DW 3 The value represented by (D) is preferably 0.05 or higher and 0.20 or lower.

[0225] like Figure 3 and Figure 4 As shown, the neck 4 has a position where at least one of its length in the thickness direction or its length in the width direction is greater than the length in the thickness direction or the length in the width direction between positions C and D in the grip portion 5. The foremost position E in this position is located at least 3 mm further forward than position B. In this embodiment, position E is located at least 4.0 mm further forward than position B. By making the grip portion 5 thinner than the rear end of the neck 4, stress is easily generated on the grip portion 5 side, enabling the grip portion 5 to flex. By placing a region thicker than the thickest part within region CD of the grip portion 5 at a position at least 3 mm further forward than position B, stress is easily generated in the grip portion 5.

[0226] If from the front end of the gripping part 5 to the rear end, such as Figure 1 As shown, the length in the thickness direction of the outline of the gripping area 5R, which includes the soft part 75, in the side view is defined as De, as follows: Figure 3 As shown, if the length of the grip portion 5 in the thickness direction in a side view is defined as Dh, then the value represented by Dh / De is preferably 0.75 or less in a continuous region of at least 20% of the length of the grip portion 5 in the long axis direction, more preferably 0.75 or less in a continuous region of at least 50% of the length of the grip portion 5 in the long axis direction, and even more preferably 0.70 or less. The maximum value of the length Dh in this continuous region is preferably 5.5 mm or more and 7.5 mm or less.

[0227] By reducing the proportion of the hard portion 60 in the thickness direction of the gripping region 5R in a continuous region of at least 20% of the length of the gripping portion 5 in the long axis direction, so that the value represented by Dh / De in the hard portion 60 is less than 0.75, the toothbrush 1 is made easy to grip and the force that causes the gripping portion 5 to flex in the thickness direction is easily generated.

[0228] If so Figure 2 As shown, the length in the width direction of the outline of the gripping area 5R, which includes the soft part 75, in the frontal view is defined as We, as follows: Figure 4 As shown, if the length of the grip portion 5 in the width direction in the front view is Wh, then the value represented by Wh / We is preferably 0.75 or less in a continuous region of at least 20% of the length of the grip portion 5 in the long axis direction, more preferably 0.75 or less in a continuous region of at least 50% of the length of the grip portion 5 in the long axis direction, and even more preferably 0.70 or less. The maximum value of the length Wh in this continuous region is preferably 5.5 mm or more and 7.5 mm or less.

[0229] By reducing the proportion of the hard portion 60 in the width direction of the gripping area 5R in a continuous region of at least 20% of the length of the gripping portion 5 in the long axis direction, so that the value represented by Wh / We in the hard portion 60 is less than 0.75, the toothbrush 1 is made easy to grip and the force that causes the gripping portion 5 to flex in the width direction is easily generated.

[0230] As described above, in the toothbrush 1 of this embodiment, depending on the direction of the applied load, starting from the grip 5, the front end of the grip 5 can flex in a large movable area in both the width and thickness directions, and the head 3 can be fully twisted in a rotational direction centered on an axis extending along the long axis. Therefore, it is possible to improve the fit to the teeth being cleaned and the cleanliness of the gaps without relying on the brushing method and technique.

[0231] [Example]

[0232] (Examples 1-8, Comparative Examples 1-5)

[0233] In this embodiment, samples of toothbrushes of Examples 1 to 8 and Comparative Examples 1 to 5 were prepared according to the specifications shown in Table 1 below.

[0234] The dimensions of each part of the toothbrush in each example are shown in Table 1. The hard resin of the brush body is PP resin, and the soft resin is thermoplastic elastomer (TPE).

[0235] In [Table 1], as an example, the length in the width direction at position A is recorded as "width (A)" and the length in the thickness direction at position A is recorded as "thickness (A)".

[0236] [Evaluation Method]

[0237] Regarding "fit to teeth and gums", the evaluation is conducted according to the following criteria: [fit to teeth and gums in the rubbing method], [fit to teeth and gums in the Fones brushing method], and [fit to teeth and gums in the Rosberg / Bass brushing method].

[0238] In this evaluation, a compact toothbrush with three rows of ST bristles implanted using a flat linear bristle implantation method was used. All bristle tufts had a diameter of 1.8 mm. The bristle tufts were arranged in three rows in the width direction and seven rows in the long axis direction. ST bristles were implanted into all implantation holes to achieve a bristle height of 12 mm. The head thickness was 3.0 mm.

[0239] [Evaluation Criteria]

[0240] (1) Adhesion of the brushing method to teeth and gums

[0241] The evaluation was conducted using a sensory test by a panel of 10 experts. The toothbrush's fit to the teeth and gums was evaluated when 1g of commercially available dental cleaning agent was placed on the toothbrush shown in each example and comparative example and brushed for 3 minutes, according to the following evaluation criteria.

[0242] The expert panel of 10 members assigned an average score of 4.5 or higher but below 5.0 as “☆ (star mark; Special Good)”, an average score of 4.0 or higher but below 4.5 as “◎ (double circle mark; Very Good)”, an average score of 3.5 or higher but below 4.0 as “○ (circle mark; Good)”, and an average score below 3.5 as “× (cross mark; Bad)”. The toothbrush marked with ☆, ◎, or ○ was considered to provide good contact with the teeth and gums during cleaning.

[0243] Evaluation Criteria

[0244] 5 points: I felt a great fit to my teeth and gums.

[0245] 4 points: I felt a great fit to my teeth and gums.

[0246] 3 points: I felt a good fit to my teeth and gums.

[0247] 2 points: I could feel a slight fit to my teeth and gums.

[0248] 1 point: I can't feel any "fit to teeth and gums".

[0249] (2) The conformity of the circular brushing method to the teeth and gums

[0250] The evaluation was conducted using a sensory test by a panel of 10 experts. The toothbrush's fit to the teeth and gums was evaluated when 1g of commercially available dental cleaning agent was placed on the toothbrush shown in each example and comparative example and brushed for 3 minutes, according to the following evaluation criteria.

[0251] The average score of the 10 expert panel members was marked as "☆" for 4.5 or above and below 5.0, "◎" for 4.0 or above and below 4.5, "○" for 3.5 or above and below 4.0, and "×" for below 3.5. The toothbrush marked with ☆, ◎, or ○ was judged as the toothbrush that provides good contact with the teeth and gums during cleaning.

[0252] Evaluation Criteria

[0253] 5 points: I felt a great fit to my teeth and gums.

[0254] 4 points: I felt a great fit to my teeth and gums.

[0255] 3 points: I felt a good fit to my teeth and gums.

[0256] 2 points: I could feel a slight fit to my teeth and gums.

[0257] 1 point: I can't feel any "fit to my teeth and gums".

[0258] (3) The fit of the Roche rotary brushing technique / Bass brushing technique to the teeth and gums

[0259] The evaluation was conducted using a sensory test by a panel of 10 experts. The toothbrush's fit to the teeth and gums when 1g of commercially available dental cleaning agent was placed on the toothbrush shown in each example and comparative example and brushed for 3 minutes was evaluated according to the following evaluation criteria.

[0260] The average score of the 10 expert panel members was marked as "☆" for 4.5 or above and below 5.0, "◎" for 4.0 or above and below 4.5, "○" for 3.5 or above and below 4.0, and "×" for below 3.5. The toothbrush marked with ☆, ◎, or ○ was judged as the toothbrush that provides good contact with the teeth and gums during cleaning.

[0261] Evaluation Criteria

[0262] 5 points: I felt a great fit to my teeth and gums.

[0263] 4 points: I felt a great fit to my teeth and gums.

[0264] 3 points: I felt a good fit to my teeth and gums.

[0265] 2 points: I could feel a slight fit to my teeth and gums.

[0266] 1 point: I can't feel any "fit to my teeth and gums".

[0267] [Table 1]

[0268]

[0269]

[0270] As shown in [Table 1], the thickness and width of the neck at position A are both 3.0 mm or more and 4.3 mm or less, and the width (A) / (B) and thickness (A) / (B) are 0.30 or more and 0.60 or less. In at least one of the bending in the width direction of the brush body measured by the above method (α) and the bending in the thickness direction of the brush body measured by the above method (β), the samples of Examples 1 to 8 that bend from the grip portion as the starting point all received good evaluations for [fit to teeth and gums in the abrasive method], [fit to teeth and gums in the circular brushing method], and [fit to teeth and gums in the Robsch rotary brushing method / Bass brushing method].

[0271] In the samples of Examples 1 to 8, the bending length when a load of 200g is applied is 6.0 mm or more and 11.0 mm or less when a load is applied in the width direction and in the thickness direction, and the rotation angle of the head based on a torque of 20 N·cm is 30° or more and 50° or less, the samples of Examples 1, 7 and 8 are evaluated as particularly well.

[0272] In the samples of Examples 1 to 8, the bending length when a load of 200g 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 rotation angle of the head based on a torque of 20 N·cm is 30° or more and 50° or less. In the sample of Example 5, particularly good evaluations were obtained in [the fit of the teeth and gums in the circular brushing method] and [the fit of the teeth and gums in the Rosberg rotary brushing method / Bass brushing method].

[0273] In the samples of Examples 1 to 8, the bending length when a load of 200g 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 rotation angle of the head based on a torque of 20 N·cm is 30° or more and 50° or less. In the sample of Example 6, particularly good evaluations were obtained in [fitting of teeth and gums in the abrasion method] and [fitting of teeth and gums in the Rosberg rotational brushing method / Bass brushing method].

[0274] In contrast, in Comparative Examples 1 and 2, where the thickness and width of the neck at position A were both 3.0 mm or more and 4.3 mm or less, but the width (A) / (B) and thickness (A) / (B) were outside the range of 0.30 or more and 0.60 or less, the samples did not receive a good evaluation in [fitting of teeth and gums in Roche-Bass brushing technique / Bass brushing technique]. Furthermore, in Comparative Example 5, where the thickness and width of the neck at position A are both 3.0 mm or more and 4.3 mm or less, but the width (A) / (B) and thickness (A) / (B) are outside the range of 0.30 or more and 0.60 or less, and no bending occurs from the gripping part when a load of 200 g is applied along the width direction or along the thickness direction, the sample did not receive a good evaluation in all categories of [fitting to teeth and gums in the rubbing method], [fitting to teeth and gums in the circular brushing method], and [fitting to teeth and gums in the Rosberg rotary brushing method / Bass brushing method].

[0275] Furthermore, in Comparative Example 3, where the neck width at position A deviated from the range of 3.0 mm to 4.3 mm, and the width (A) / (B) ratio deviated from the range of 0.30 to 0.60, the sample did not receive a good evaluation in the [fitting properties to teeth and gums during the circular brushing technique]. In Comparative Example 4, where the neck thickness at position A deviated from the range of 3.0 mm to 4.3 mm, and the thickness (A) / (B) ratio deviated from the range of 0.30 to 0.60, the sample did not receive a good evaluation in the [fitting properties to teeth and gums during the Rosberg rotary brushing technique / Bass brushing technique].

[0276] The above is with reference to the appendix. Figure 1 The preferred embodiments of the present invention have been described, but the present invention is of course not limited to these examples. The shapes, combinations, etc. of the structural components shown in the above examples are just one example, and various changes can be made based on design requirements, etc., without departing from the spirit of the present invention.

[0277] Industrial availability

[0278] This invention can be applied to toothbrushes.

Claims

1. A toothbrush, characterized in that, have: A hair-embedded section composed of multiple hair tufts; and The brush body extends along its long axis. The brush body has a rigid portion formed of hard resin. The hard portion has: The head is located at the front end in the long axis direction, and the hair-planting part is disposed on the hair-planting surface; A grip portion located at the rear end of the head along its long axis; as well as The neck, located between the head and the grip, Let position A be the front end of the neck along its long axis. Let the position of the rear end of the neck in the long axis direction be B. When the direction orthogonal to the hair-planting surface is defined as the thickness direction, and the direction parallel to the hair-planting surface and orthogonal to the thickness direction is defined as the width direction... The length of the neck at position A in both the thickness direction and the width direction is 3.0 mm or more and 4.3 mm or less. The ratio of the length of the neck in the width direction at position A to the length of the neck in the width direction at position B is 0.30 or more and 0.60 or less. The ratio of the length of the neck in the thickness direction at position A to the length of the neck in the thickness direction at position B is 0.30 or more and 0.60 or less. The bending length in both the width direction and the thickness direction is 6.0 mm or more and 11.0 mm or less. If the position of the front end of the gripping part in the long axis direction is set as C, Let D be a position that is 50% of the length of the grip portion along its major axis, extending from the front end to the rear end. Let the length of the grip portion in the thickness direction be D mm, and the length in the width direction be W mm. W×D at position C 3 The value represented is set as WD. 3 (C) mm 4 , W×D at position D 3 The value represented is set as WD. 3 (D)mm 4 , D×W at position C 3 The value represented is set as DW. 3 (C) mm 4 , D×W at position D 3 The value represented is set as DW. 3 (D)mm 4 , Then WD 3 (C) is 410mm 4 Above and 4000mm 4 the following, WD 3 (C) / WD 3 (D) represents a value greater than 0.35 and less than 2.

0. DW 3 (C) is 410mm 4 Above and 4000mm 4 the following, DW 3 (C) / DW 3 (D) represents a value greater than 0.35 and less than 2.

0. The length of the neck in both the thickness and width directions is constant or gradually increases in diameter from the front end to the rear end. The neck has a position where at least one of its length in the thickness direction and its length in the width direction is greater than either the length in the thickness direction or the length in the width direction between position C and position D in the grip portion. The position E closest to the front end of this location is located at least 3mm further from the front end than position B. In at least one of the bending in the width direction of the brush body measured by the method described below (α) and the bending in the thickness direction of the brush body measured by the method described below (β), the bending originates from the grip portion. Method (α): For a position that is 40% of the length of the long axis of the grip from the front end to the rear end of the grip, the height of the front end of the brush body in a fixed state is set as the reference height. In the fixed state, a load of 200g is applied to the center position of the bristle section in the head along the width direction. The starting position of the bending is measured after 10 seconds. The displacement of the front end of the brush body relative to the reference height in the width direction is measured as the bending length, in mm. Method (β): For a position that is 40% of the length of the long axis of the grip from the front end to the rear end, the height of the front end of the brush body in a fixed state is set as a reference height. In the fixed state, a load of 200g is further applied to the center position of the bristle section in the head along the thickness direction in the long axis direction. The starting position of the bending is measured after 10 seconds, and the displacement of the front end of the brush body relative to the reference height in the thickness direction is measured as the bending length, in mm.

2. The toothbrush according to claim 1, characterized in that, When the head is rotated about an axis extending along the long axis by a force of 20 N·cm, the rotation angle of the head is more than 30° and less than 50°.

3. The toothbrush according to claim 1 or 2, characterized in that, If the length of the neck in the thickness direction is set as D mm, and the length in the width direction is set as W mm, W×D at position A 3 The value represented is set as WD. 3 (A) mm 4 , W×D at position B 3 The value represented is set as WD. 3 (B) mm 4 , D×W at position A 3 The value represented is set as DW. 3 (A) mm 4 , D×W at position B 3 The value represented is set as DW. 3 (B) mm 4 , Then WD 3 (B) is 1200mm 4 Above and 6500mm 4 the following, WD 3 (A) / WD 3 (B) represents a value greater than 0.01 and less than 0.

20. DW 3 (B) is 1200mm 4 Above and 6500mm 4 the following, DW 3 (A) / DW 3 (B) represents a value greater than 0.01 and less than 0.

20.

4. The toothbrush according to claim 1 or 2, characterized in that, In a continuous region of at least 20% of the length of the grip portion in the long axis direction, the length of the grip portion in both the thickness direction and the width direction is 4.5 mm or more and 8.0 mm or less.

5. The toothbrush according to claim 1 or 2, characterized in that, The ratio of the width-direction length of the grip portion at position C to the width-direction length of the grip portion at position D is 0.65 or more and 1.30 or less. The ratio of the length of the grip portion in the thickness direction at position C to the length of the grip portion in the thickness direction at position D is 0.65 or more and 1.30 or less.

6. The toothbrush according to claim 1 or 2, characterized in that, At least a portion of the gripping part is covered by a soft part formed of soft resin. In a continuous region extending from the front end of the grip portion towards the rear end, along the long axis of the grip portion, at least 20% of its length, If we define the length of the thickness direction, including the soft part, in the side view of the gripping part observed along the width direction as De, then... Let Dh be the length of the grip portion in the thickness direction from the side view. Let We be the length of the width direction, including the soft part, in the frontal view of the grip portion observed along the thickness direction. Let the length of the grip portion in the width direction in the frontal view be Wh. The value represented by Dh / De is below 0.

75. The value represented by Wh / We is below 0.75.

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