JP6596946B2 - Interdental cleaning tool and manufacturing method thereof - Google Patents

Description

  The present invention relates to an interdental cleaning tool having a cleaning portion covered with an elastomer and a method for manufacturing the same.

  As an interdental cleaning tool, a base part made of synthetic resin and a soft part made of elastomer are provided, and the base part is a handle base part and an elongated shaft-like shape provided at the tip of the handle base part A core base part, and the soft part has at least a soft cleaning part for covering the core base part, and the handle base part constitutes a handle part as a handle, and the core What comprised the cleaning part for interdental cleaning with the base-material part and the soft part for cleaning is utilized practically (for example, refer patent documents 1-5).

  As a method for manufacturing the interdental cleaning tool, a base material part is manufactured by filling a first molding space of a first mold with a synthetic resin material, and the base part molded by the first mold is a second metal. The mold was set in the second molding space, and the first mold and the second mold of the second mold were spaced apart in the length direction of the second molding space (the axial direction of the core base material). With a plurality of sets of holding pins extending in the mold opening and closing direction, with the core base material portion positioned and held in the center of the second molding space, filling the second molding space with an elastomer material and molding the soft part, A manufacturing method for obtaining an interdental cleaning tool has been widely adopted. In addition, normally, a plurality of first molding spaces are provided in the first mold so that a plurality of interdental cleaning tools can be simultaneously molded, and the second molding having the same number as the first molding spaces is provided in the second mold. When manufacturing the interdental cleaning tool by providing a space, the synthetic resin material is supplied to the plurality of first molding spaces and manufactured simultaneously so that the plurality of substrate parts are connected by the runner part. Then, by setting a primary molded product composed of a plurality of base material parts connected by a runner part in the second molding space of the second mold, and filling the plurality of second molding spaces with an elastomer material. A plurality of interdental cleaning tools are formed at the same time.

Japanese Patent No. 4236571 Japanese Patent No. 3002668 Special table 2001-506514 gazette JP2013-192866A JP 2013-188299 A

  By the way, when the cleaning part is inserted between the teeth, a large compression force acts in the axial direction. Also, when cleaning between molars, especially between molars, insert between the molars while curving from 60 ° to 90 ° from the tip to the middle of the interdental cleaning tool inserted in the front-rear direction with respect to the oral cavity. When cleaning between teeth, it is necessary to put in and out the cleaning portion with respect to the gap between the molar teeth in a curved state, so that a large bending load acts on the cleaning portion. For this reason, in the interdental cleaning tool in which the base material portion is made of a synthetic resin material, countermeasures against breakage of the cleaning portion during insertion between the teeth or during interdental cleaning are one of the important issues.

  As a countermeasure against breakage of the cleaning portion, a synthetic resin material constituting the base material portion with glass fiber added has been proposed. However, when glass fiber is added, the strength rigidity in the core axis direction of the core base material portion is increased, and the insertability into the interdental portion is improved. A strong force is required, and a large bending load is likely to act on the core base material portion during cleaning between molars, causing a problem that the core base material portion breaks in the middle in the length direction.

  In addition, the inventor, as a cause of the breakage of the core base material portion, there is a concave portion at the position where the holding pin for positioning the core base material portion and the core base material portion contact in the second mold when the soft part for cleaning is molded. It is easy to form, the cross-sectional area of the core base material is reduced at the position of the recess, the stress generated in the core base is increased, and the presence of the recess at the site where high stress is concentrated causes structural changes. It has been found that the core base material part breaks in the vicinity of the axial position where the recess is formed due to bending stress acting during insertion between teeth or during interdental cleaning.

  Although the mechanism by which the concave portion is formed in the core base material portion by the holding pin is not clear, it can be estimated that the concave portion is formed by the following mechanism. That is, the base material part molded with the first mold is set in the second mold after cooling, but in order to shorten the molding time, it is set in the second mold at a relatively high temperature, and The base material set in the two molds is softened during the molding of the cleaning soft portion because it is exposed to the high temperature elastomer filled in the second molding space. Further, in the second mold, a plurality of sets of holding pins are projected into the second molding space by a preset projection length, and the core base material portion is positioned at the center of the second molding space. Variations in the molding dimensions of the core base material due to molding shrinkage differences due to shortening of the molding time, or thermal expansion of the core base material due to exposure to a high temperature elastomer, and the core during elastomer filling It can be presumed that the tip portion of the holding pin bites into the core base material portion due to vibration of the base material portion, and a recess is formed in the core base material portion.

  Further, in the so-called I-type interdental cleaning tool in which the center line of the handle part and the axis of the core base material part are arranged coaxially, the handle part is configured in a flat shape so that it can be easily picked up with fingers. In some cases, the handle portion is usually configured to be flat with respect to the mold opening and closing directions of the first mold and the second mold, and the holding pins are arranged in the axial direction of the holding pins in order to make the mold structure as simple as possible. Are arranged in the mold opening / closing direction of the second mold. For this reason, in the I-type interdental cleaning tool, when the handle portion is picked and the interdental teeth are cleaned, the concave portion of the core base material portion formed by the holding pins is formed on the outer peripheral side and the inner side of the curved core base material portion. It has been found that the core base material portion is easily broken when the stress is increased near the concave portions on both the inner and outer peripheral sides and stress concentration occurs.

  The object of the present invention is to effectively prevent the occurrence of the breakage of the core base material portion during insertion and interdental cleaning without reducing the productivity of the interdental cleaning tool with a simple configuration. It is providing the interdental cleaning tool and its manufacturing method.

  An interdental cleaning tool according to the present invention includes a base material portion made of a synthetic resin and a soft portion made of an elastomer covering at least a part of the base material portion, and the base material portion includes a handle base material portion and An elongated shaft-shaped core base material portion provided continuously with a tip portion of the handle base material portion, and the soft portion includes at least a cleaning soft portion covering the core base material portion, and the handle An interdental cleaning tool comprising a handle portion as a handle in a base material portion, and a cleaning portion for interdental cleaning formed by the core base material portion and a soft cleaning portion, the first of the cleaning portion In each of the side part and the second side part, a cleaning part recess that penetrates the cleaning soft part and forms a core base part recess in the core base part is spaced apart in the axial direction of the cleaning part. At least one set of cleaning section recesses among a plurality of sets of cleaning section recesses paired by the first side portion and the second side portion. The center line in the depth direction passing through the center of, with respect to the mold opening and closing direction of the mold for molding the cleaning soft portion, and forming an angle in the circumferential direction of the cleaning unit. In addition, the 1st side part and 2nd side part of a cleaning part are one side half part of the outer peripheral surface of the cleaning part shape | molded by one metal mold | die in the 2nd metal mold | die which forms a cleaning part, and the other side. It means the remaining half on one side of the outer peripheral surface of the cleaning part formed by a mold.

  When manufacturing this interdental cleaning tool, the first molding space of the first mold is filled with a synthetic resin material to mold the base material portion, and the base material portion molded by the first mold is used as the second base material portion. A plurality of holding pins that are set in the second molding space of the mold and provided in the first mold and the second mold of the second mold with a space in the length direction of the second molding space, With the base material portion held in the center of the second molding space, the soft material is molded by filling the second molding space with an elastomer material. And the cleaning part recessed part is formed in the position where the front-end | tip part of a holding pin contacts a core base material part in the 1st side part and 2nd side part of the cleaning part in the interdental cleaning tool manufactured in this way, In addition, a plurality of sets of core base material recesses formed by pressing the tip portions of the holding pins into the core base material portion are generated at intervals in the axial direction of the core base material portion.

  In addition, by using a holding pin with an angle in the mold opening / closing direction, at least one set of cleaning portion recesses among the plurality of cleaning portion recesses paired with the first side portion and the second side portion. A center line segment in the depth direction passing through the center of the cleaning portion can be formed at an angle in the circumferential direction of the cleaning portion with respect to the mold opening / closing direction of the mold for forming the cleaning soft portion. And when comprised in this way, when forming the some cleaning projection part which protrudes outward in the soft part for cleaning, the freedom degree of arrangement | positioning layout of this projection part for cleaning can be improved. That is, the cleaning portion recess is formed by the holding pin that holds the core base material portion in the center portion of the second molding space, but the position of the holding pin does not interfere with the formation position of the cleaning protrusion. Since it can adjust to a length direction and a circumferential direction with respect to the 2nd shaping | molding space, the freedom degree of arrangement | positioning layout of this cleaning projection part can be improved. Further, in the I-type interdental cleaning tool with a flat handle portion, the cleaning direction of the cleaning portion at the time of cleaning between molars is generally determined, so that the cleaning portion recess is not disposed on the outer peripheral side surface of the bending direction. In addition, by adjusting the position of the core base part recess in the circumferential direction of the core base part, it is possible to effectively prevent the cleaning part from being broken due to stress concentration at the position of the core base part recess.

  Here, it is a preferred embodiment to provide a pair of cleaning recesses with the angle at a location where stress concentration is likely to occur in the core base material. For example, when cleaning between molars, the largest bending stress acts at a position of 5 to 6 mm from the distal end of the cleaning part, so that one set of cleaning parts with the angle is used as one set of cleaning part recesses in the part. By providing the concave portion, it is possible to effectively prevent the cleaning portion from being broken during cleaning between molars.

  It is a preferred embodiment that the angle is set to 60 ° or more. When the angle exceeds 60 °, when a plurality of interdental cleaning tools are arranged in parallel and formed, in the second mold for forming the soft portion, the adjacent interdental space forming the cleaning portion recess Since the holding pins of the cleaning tool interfere with each other, a plurality of interdental cleaning tools arranged in parallel cannot be packed and molded, and the number of interdental cleaning tools is reduced. It is preferable to do.

  It is also possible to provide a plurality of sets of cleaning section recesses with the angle, and set the angles in the plurality of sets to different angles with each other or with any combination of cleaning section recesses. By comprising in this way, the freedom degree of arrangement | positioning layout of this cleaning projection part when forming the projection part for cleaning in the soft part for cleaning can be improved further.

  The center line of the handle portion and the axis of the core base material portion are arranged coaxially, and the handle base material portion is formed in a thin flat shape in a mold opening / closing direction that can be picked and held by a finger. This is a preferred embodiment. In the interdental cleaning tool having such a configuration, when the handle base material portion is picked and the interdental teeth are cleaned, the surface is substantially orthogonal to the surface including the flat handle base material portion (the surface extending in the mold opening / closing direction). The cleaning portion is curved, and the largest bending stress acts at a position of 5 to 6 mm from the tip of the cleaning portion. For this reason, as in the present invention, the central portion of the depth direction passing through the center of at least one set of the cleaning portion recesses is set to the mold opening / closing direction of the mold for molding the cleaning soft portion. By forming an angle in the circumferential direction, the cleaning portion recess is prevented from being placed outside the curvature of the cleaning portion during cleaning between molars, and stress concentration occurs on the cleaning portion recess. Can be alleviated, and breakage of the cleaning portion during cleaning between molars can be effectively prevented.

  In addition, it is also possible to provide the interdental cleaning tool according to the present invention described above in any combination of the following configurations.

(1) If there is a cleaning portion recess with the angle and other recesses, a specific or all of the first side cleaning portion recesses to be formed in the interdental cleaning tool, including that, and The corresponding second side cleaning portion recess can be formed in a face-to-face configuration with the core base material interposed therebetween, and is spaced in the axial direction of the cleaning portion so as not to overlap in the circumferential direction of the cleaning portion. The cleaning part recess formed in a face-to-face manner and the cleaning part recess formed at an interval in the axial direction of the cleaning part so as not to overlap in the circumferential direction of the cleaning part can be arbitrarily formed. It can also be formed in combination. Here, the term “face-to-face” means that a straight line connecting portions where the tip portions of the holding pins to be in contact with each other passes through the vicinity of the axial center of the core base material portion.

  The axial direction of the cleaning part is such that the first side cleaning part recess formed in the interdental cleaning tool and the corresponding second side cleaning part recess do not overlap in the circumferential direction of the cleaning part. When the soft part is formed, the core base part recesses are alternately formed on the first side part and the second side part of the core base part, and the core base part has the same axial direction. Since a pair of core base material recesses can be prevented from being formed at the position, the cross-sectional area of the core base material at the position corresponding to the core base material recess is increased, and the core base material breaks. Can be prevented. Moreover, since the core base material portion can be prevented from being deepened even when the core base material portion is bent between the holding pins during molding of the soft portion, the position corresponding to the core base material portion recess As a result, the cross-sectional area of the core base material portion becomes larger, and the occurrence of breakage of the core base material portion can be prevented. Furthermore, since the interval between the holding pins with respect to the length direction of the core base material portion is substantially shortened, the core base material portion can be stably held. In addition, in this specification, the cleaning part recessed part of the 2nd side part corresponding to the cleaning part recessed part of the 1st side part means the same cleaning part recessed part counted from the front-end | tip of a cleaning part.

(2) The maximum depth of the core base material recess formed in the core base material portion is 0.01 mm, including the above-mentioned angled core base material recess and other recesses. It can be configured to be 0.085 mm or less. Suppressing the reduction of the cross-sectional area of the core base material portion (cross-sectional area perpendicular to the axial direction of the core base material portion) at the formation position of the core base material concave portion, and suppressing the occurrence of stress concentration in the core base material portion concave portion At the same time, even if there is a concave structure at the position where stress is concentrated, it is difficult to affect the change in the structure of the core base material. Can be prevented. For this reason, it is possible to effectively prevent the core base material portion from being bent during insertion between teeth or during interdental cleaning while forming the base material portion with a synthetic resin material excellent in productivity. In addition, the maximum depth of a core base-material part recessed part means the largest distance among the shortest distances from the outer surface to the bottom face of the opening part of a core base-material part recessed part. That is, as shown in FIG. 25, the center line in the depth direction of the core base material recess 14a (core base material) passing through the center P1 of the opening of the cleaning recess 14 and the center P2 of the bottom of the cleaning recess 14 is shown. The surface of the core recess 12 including the center line CL) is defined as a reference plane BS that is parallel to the center line CL of the core base 12 and the core base recess is defined by a cutting plane CS parallel to the reference plane BS. When it is assumed that 14a has been cut sequentially, the core base material recess 14a is formed from a line segment UL connecting the front end T and the rear end B at the cut surface CS of the opening of the core base material recess 14a. It means the maximum length of all the cut surfaces among the lengths of the center line DLa that is lowered to the bottom surface in parallel with the line segment DL in the depth direction.

  In addition, if there is a core base part recess having the angle and other recesses, the maximum cross-sectional area of the core base part at a position corresponding to the core base part recess is determined. An embodiment in which the cross-sectional area of the core base material portion at a position adjacent to the base material portion recess is preferably set to 55.0 to 99.6%, more preferably 80.0 to 97.9%. It is. If comprised in this way, the stress concentration in a core base-material part recessed part will be decreased, and the breakage of the core base-material part at the time of insertion between teeth and the cleaning between teeth can be prevented much more effectively.

(3) Forming at least one of the plurality of cleaning section recesses in an elongated shape in the axial direction of the cleaning section, including the cleaning section recess with the angle and other recesses, if any. You can also. If the diameter of the concave portion of the cleaning portion is reduced, the holding pin forming the concave portion of the cleaning portion has a small diameter, the contact area of the holding pin with respect to the core base material portion is reduced, and the depth of the concave portion of the core base material portion is likely to be deep. The stress concentration is likely to occur at the position where the core base portion recess is provided. For this reason, if comprised as mentioned above, the width | variety of a cleaning part recessed part is narrowed, and the width | variety of a holding pin is made small, improving the freedom degree of arrangement | positioning layout of the projection part for cleaning, and a core base material part It is preferable because the contact area of the holding pin with respect to the core can be increased to reduce the depth of the core base portion recess, and the stress concentration can be effectively prevented from occurring at the position where the core base portion recess is provided.

(4) At least one of a fiber material and talc can be added to the synthetic resin material constituting the base portion. By comprising in this way, the strength rigidity with respect to the bending stress of a core base-material part can be improved, and the insertion property of the cleaning part with respect to between teeth can be improved. Moreover, since the rigidity in the core axis direction of the core base material portion can be increased, the depth of the recess formed in the core base material portion is difficult to increase, and stress concentration at the position where the core base material portion recess is provided is reduced. It is also preferable for preventing the occurrence.

(5) Three or more cleaning portion recesses on at least one side of the first side portion and the second side portion including the cleaning portion recess having the angle and other recesses, if any. Is a preferred embodiment. When three or more cleaning section recesses are provided on at least one side, the unevenly distributed portion of the bending stress that acts on the cleaning section when inserted between teeth or during interdental cleaning is placed at the position where three or more cleaning section recesses are formed. The core substrate portion can be effectively prevented from being bent due to a large bending stress acting locally. In addition, increasing the number of cleaning part recesses increases the number of holding pins provided in the second mold for molding the soft part, so that the contact area of the holding pin with respect to the core base material part increases, and at the time of molding the soft part Since the vibration of the core base material can be suppressed and the control to reduce the depth of the core base material recess is facilitated, stress concentration at the position of the core base material recess is effectively prevented during interdental cleaning. It is preferable because it is possible. In addition, the cleaning part recessed part of a 1st side part and a 2nd side part can also be set to the same number, and can also be set to a different number. When the cleaning portion recess on the first side and the cleaning portion recess on the second side are arranged facing each other, the same number is set, but the cleaning portion recess on the first side and the second side When the cleaning unit recess and the cleaning unit are provided with the arrangement interval shifted in the axial direction, the number of both can be set to a different number, for example, only one first side part than the second side part. The number of cleaning unit recesses can be reduced.

(6) If there is a cleaning section recess with the angle and other recesses, the cleaning section recess is disposed substantially uniformly with respect to the axial direction of the cleaning section. It is also a preferred embodiment to set it so that it becomes narrower as it goes to the tip side. In the most preferred embodiment, the interval between the cleaning portion recesses with respect to the axial direction of the cleaning portion is set to a substantially uniform interval. The distal end portion of the cleaning portion is a substantially linear and elongated shaft-like structure having a smaller diameter than the base end portion, and is structurally susceptible to structural changes with respect to the molding pressure during molding of the cleaning soft portion. Therefore, as in the present invention, if the interval between the cleaning portion recesses is set so as to become narrower or substantially uniform as it goes to the distal end side of the cleaning portion, the core is formed during molding of the soft portion. It becomes easy to prevent the base material portion from moving from a predetermined position. In particular, it is more preferable that the distance is substantially uniform because the external force received by the core base material portion during the soft portion molding tends to be uniform.

(7) If there is a core base part recess having the angle and other recesses, the opening areas of the plurality of core base part recesses are substantially the same as each other or the plurality of core bases. It is preferable to set so that the core base portion concave portion on the most distal side among the material portions is the smallest. The core base material portion is a long and narrow cone-like structure, and its cross-sectional area decreases as it goes to the front end side. Therefore, it is preferable to set the opening area at the front end portion where the cross-sectional area is the smallest to be the smallest. That is, since the opening area of the core base portion recess changes according to the tip end area of the holding pin that holds the core base portion with respect to the central portion of the second molding space, the most distal end of the core base portion The tip end area of the holding pin located on the side is substantially the same or the smallest compared to the tip end area of the holding pin at the other position. On the other hand, the molding area for molding the cleaning soft part in the second molding space has a narrow passage area on the tip side of the second molding space. For this reason, as in the present invention, the opening area of the core base part recess on the most tip side of the core base part is set as small as possible, that is, the tip part area of the holding pin on the tip side is reduced, 2 When the passage area of the molding space is set as large as possible, the flow resistance of the elastomer material can be set as small as possible, and the influence of Karman vortex generated around each holding pin on the molded body and holding pin can be further suppressed. The holding | maintenance of a material part can be improved, and the filling defect of the elastomer material with respect to the soft part shaping | molding part for cleaning can be prevented.

(8) It is preferable that the handle base material portion and the core base material portion are arranged on substantially the same axis line including the concave portion of the core base material portion and the other concave portions provided with the angle. It is an embodiment. As the interdental cleaning tool, it is also possible to adopt an interdental cleaning tool in which the core base material portion is provided at an angle of about 120 ° with respect to the handle base material portion in consideration of insertability between molars. However, when the handle base material portion and the core base material portion are arranged on substantially the same axis as in the present invention, a plurality of interdental cleaning tools can be closely arranged in parallel and molded, and interdental cleaning is possible. This is preferable because the number of tools can be increased.

(9) In a preferred embodiment, the base material portion is composed of a thermoplastic synthetic resin material having a crystallinity with a melting point of 150 ° C. or higher. When a base material part is molded using a thermoplastic synthetic resin material having such a melting point, the productivity of the interdental cleaning tool is improved by shortening the molding time of the base material part, in particular, the cooling time to increase the production efficiency. As a result, the manufacturing cost of the interdental cleaning tool can be reduced.

  The manufacturing method of the interdental cleaning tool according to the present invention includes a base material portion made of a synthetic resin and a soft portion made of an elastomer that covers at least a part of the base material portion. And a slender shaft-shaped core base material portion provided continuously to a tip portion of the handle base material portion, and the soft portion includes at least a cleaning soft portion that covers the core base material portion. The handle base material part constitutes a handle part as a handle, and the interdental cleaning tool manufacturing method comprises an interdental cleaning part composed of the core base material part and the cleaning soft part, Synthetic resin material is supplied to the first molding space of the first mold to form the base material part, and the base material part formed in the base material part molding process is replaced with the soft part. Set in the second molding space of the second mold to be molded, and set in the second mold with an interval in the length direction of the second molding space. Further, the core base material portion is formed such that a core base material portion recess is formed in the core base material portion with a plurality of sets of holding pins that are paired with the first die and the second die of the second mold. A soft part molding step of molding the soft part by filling the second molding space with an elastomer material in a state where the soft part molding part is held at a substantially central part of the cleaning soft part molding part. The center line of at least one pair of holding pins is provided at an angle with respect to the mold opening / closing direction of the second mold.

  In this manufacturing method, the center line segment of at least one set of holding pins out of a plurality of sets of holding pins paired with the first mold and the second mold in the second mold is used as the mold of the second mold. Since the circumferential direction of the second molding space is formed at an angle with respect to the opening / closing direction, when the plurality of cleaning protrusions protruding outward are formed on the cleaning soft part, the cleaning The degree of freedom of the layout of the protrusions can be improved. In other words, the soft portion is molded with the core base material portion held at the central portion of the second molding space by the plurality of holding pins, but the position of the holding pin does not interfere with the forming position of the cleaning protrusion. Thus, since it can adjust to a length direction and a circumferential direction with respect to 2nd shaping | molding space, the freedom degree of arrangement | positioning layout of this cleaning projection part can be improved. Further, in the I-type interdental cleaning tool with a flat handle portion, the cleaning direction of the cleaning portion at the time of cleaning between molars is generally determined, so that the cleaning portion recess is not disposed on the outer peripheral side surface of the bending direction. In addition, by adjusting the position of the core base part recess in the circumferential direction of the core base part, it is possible to effectively prevent the cleaning part from being broken due to stress concentration at the position of the core base part recess.

  Here, it is preferable to provide a pair of holding pins with the angle corresponding to a portion where stress concentration is likely to occur in the core base material portion. In this case, in the I-type interdental cleaning tool as described above, stress concentration occurs at the time of cleaning between molar teeth at the position of the concave portion of the core base material portion formed by a set of angled holding pins. Thus, the cleaning part can be effectively prevented from being broken.

  The angle can be set to 60 ° or less, preferably 60 ° or less, preferably 5 ° or more, and more preferably 45 ° or less and 10 ° or more. When the angle exceeds 60 °, when a plurality of interdental cleaning tools are arranged in parallel and formed, in the second mold for forming the soft portion, the adjacent interdental space forming the cleaning portion recess Since the holding pins of the cleaning tool interfere with each other, a plurality of interdental cleaning tools arranged in parallel cannot be packed and molded, and the number of interdental cleaning tools is reduced or the mold size is increased. Therefore, it is preferable to set it to 60 ° or less. If it is less than 5 °, the stress concentration in the vicinity of the recesses on both the inner and outer circumferences cannot be sufficiently relaxed, which is not preferable.

  A plurality of sets of holding pins with the angle may be provided, and the angles in the plurality of sets may be set to different angles with each other or with any combination of holding pins. By comprising in this way, the freedom degree of arrangement | positioning layout of this cleaning projection part when forming the projection part for cleaning in the soft part for cleaning can be improved further.

  In addition, it is also possible to provide the above-described method for manufacturing an interdental cleaning tool according to the present invention by arbitrarily combining the following configurations.

(1) The elastomer material can be filled from the distal end side of the second molding space, or the elastomer material can be filled from the proximal end side of the second molding space.

(2) The first base holding pin and the second type holding pin of the second mold including the holding pin having the angle and the other holding pin, and the core base material portion. Can be provided in a face-to-face relationship, and can be provided with a gap in the length direction of the second molding space so as not to overlap in the circumferential direction of the second molding space. The holding pins and the holding pins provided at intervals in the length direction of the second molding space can be provided in any combination so as not to overlap in the circumferential direction of the second molding space.

  When the first type holding pin and the corresponding second type holding pin are formed at intervals in the length direction of the second molding space so as not to overlap in the circumferential direction of the second molding space, a core is formed. The core base part recesses are alternately formed on the first side part and the second side part of the base part, and a pair of core base part recesses are formed at the same position in the axial direction of the core base part. Therefore, the cross-sectional area of the core base material portion at a position corresponding to the core base material portion concave portion can be increased, and the occurrence of breakage of the core base material portion can be prevented. In addition, since the core base material portion can be prevented from being deepened by bending the core base material portion between the holding pins when the soft portion is molded, The cross-sectional area of the core base material portion at the corresponding position is increased, and the occurrence of breakage of the core base material portion can be prevented. Furthermore, since the interval between the holding pins with respect to the length direction of the core base material portion is substantially shortened, the core base material portion can be stably held. In addition, the 2nd type | mold holding pin corresponding to a 1st type | mold holding pin means the same holding pin counted from the front-end | tip of 2nd shaping | molding space, for example.

(3) The first mold of the second mold is spaced apart in the length direction of the second molding space including the holding pins with the angle and the other holding pins, if any. The tip end portion of the holding pin provided in each of the second mold is brought into contact with the core base material portion, and an appropriate load is applied to the core base material portion so that the core base material portion is cleaned with a soft portion for cleaning. A core having a maximum depth of 0.01 mm or more and 0.085 mm or less is formed in the core base material portion while filling the second molding space with an elastomer material and molding a soft portion while being held at a substantially central portion of the molding portion. It is also preferable to form a substrate part recess.

  In this case, the core substrate portion can be stably held with respect to the appropriate position of the second molding space by the plurality of holding pins, the molding accuracy of the interdental cleaning tool can be improved, and the core substrate Ensure sufficient cross-sectional area of the core base material at the position where the concave part is formed, suppress the occurrence of stress concentration in the part, and break the core base material part during insertion or interdental cleaning Can be prevented. Note that the maximum depth of the concave portion of the core base material portion can be adjusted by adjusting the length of the holding pin or by adjusting the length of the holding pin in addition to adjusting the load applied to the core base material portion by the holding pin tip as described above. It can be adjusted to a desired depth by exchanging it with a different one.

(4) At least one of a fiber material and talc can be added to the synthetic resin material constituting the base portion. By comprising in this way, the strength rigidity with respect to the bending stress of a core base-material part can be improved, and the insertion property of the cleaning part with respect to between teeth can be improved. Moreover, since the rigidity in the core axis direction of the core base material portion can be increased, the depth of the recess formed in the core base material portion is difficult to increase, and stress concentration at the position where the core base material portion recess is provided is reduced. It is also preferable for preventing the occurrence.

(5) Three or more holding pins in at least one of the first mold and the second mold of the second mold, including the holding pins with the angle and other holding pins, if any. Is a preferred embodiment. If comprised in this way, since the 3 or more cleaning part recessed part is formed in the at least one side part of the 1st side part and 2nd side part of a cleaning part with a holding pin, it is the interdental produced by this manufacturing method. The cleaning tool can disperse and absorb the bending stress acting on the cleaning part at the time of insertion between teeth or between teeth at three or more cleaning part positions where the cleaning part recesses are formed. It is possible to effectively prevent the core base material from being bent due to the large bending stress. In addition, when three or more holding pins are provided, the contact area of the holding pins with respect to the core base material portion can be increased, and the vibration of the core base material portion during molding of the soft portion can be suppressed. Since it can suppress that depth becomes deep, since generation | occurrence | production of the stress concentration of the position of the core base-material recessed part at the time of interdental cleaning can be prevented effectively, it is preferable. In addition, the 1st type | mold and 2nd type | mold holding pin in a 2nd metal mold | die can also be set to the same number, and can also be set to a different number. When the first-type holding pins and the second-type holding pins are arranged facing each other, they are set to the same number. However, the first-type holding pins and the second-type holding pins are arranged in the second molding space. When the arrangement positions are shifted in the length direction, the number of both can be set differently. For example, the number of holding pins can be reduced by only one for the first type than for the second type. it can.

(6) In the case where there are the holding pins with the angle and other holding pins, the arrangement interval of the holding pins with respect to the length direction of the second molding space is preferably substantially uniform, It can also be made narrower as it goes to the tip side of the second molding space. As described above, the distal end of the cleaning portion is a substantially straight and elongated shaft-like structure having a smaller diameter than the base end portion, and structurally changes with the molding pressure during molding of the cleaning soft portion. Easy to do. Therefore, as in the present invention, when the holding pin is arranged so that the interval between the holding pins becomes narrower toward the front end side of the second molding space or is set to be substantially uniform, the flexible portion is molded. It becomes easy to prevent the core base material portion from moving from a predetermined position. In particular, it is the most preferred embodiment that the arrangement interval of the holding pins with respect to the length direction of the second Seike space is set to a substantially uniform interval. If comprised in this way, since the external force which a core base material part receives at the time of soft part shaping | molding tends to become uniform, it is more preferable.

(7) The cross-sectional areas of the front end portions of the plurality of holding pins are substantially the same as each other, including the angled holding pins and other holding pins, and the most distal ends of the second molding spaces. It is also a preferred embodiment to set the holding pin on the side to be the smallest. That is, the passage area of the second molding space for molding the cleaning soft portion becomes narrower toward the tip side. Therefore, as in the present invention, by reducing the cross-sectional area of the tip of the holding pin (the cross-sectional area perpendicular to the axial direction of the holding pin), the cross-sectional area of the entire holding pin can be reduced, thereby reducing the passage area. It can be set as large as possible, the flow resistance of the elastomer material can be set as small as possible, and the influence of Karman vortex generated around each holding pin and the holding pin can be further suppressed, and the core base material can be held. Can be improved, and poor filling of the elastomer material into the cleaning soft part molding part can be prevented. Note that the cross-sectional area of the tip of the holding pin is almost the same as the area of the opening of the recessed portion of the cleaning portion formed by taking account of these because fluctuations in the area due to blurring and expansion / contraction during molding are extremely small. It can be estimated that they will be the same.

  According to the interdental cleaning tool and the manufacturing method thereof according to the present invention, the length of the holding pin for forming the cleaning portion recess is long with respect to the second forming space so as not to interfere with the forming position of the cleaning protrusion. Since it can adjust to a direction and a circumferential direction, the freedom degree of arrangement | positioning layout of this cleaning projection part can be improved. Further, in the I-type interdental cleaning tool with a flat handle portion, the cleaning direction of the cleaning portion at the time of cleaning between molars is generally determined, so that the cleaning portion recess is not disposed on the outer peripheral side surface of the bending direction. In addition, by adjusting the position of the core base part recess in the circumferential direction of the core base part, it is possible to effectively prevent the cleaning part from being broken due to stress concentration at the position of the core base part recess.

Front view of interdental cleaning tool assembly (A) of the interdental cleaning tool assembly is a front view, and (b) is a side view. Enlarged front view of the vicinity of the connecting part of the interdental cleaning tool assembly Sectional view taken along line IV-IV in FIG. (A) of the cleaning part is an enlarged front view, (b) is an enlarged side view Sectional view taken along line VI-VI in FIG. VII-VII sectional view of FIG. VIII-VIII sectional view of FIG. Enlarged front view of the cleaning part of another configuration FIG. 6 equivalent view of the cleaning unit of another configuration FIG. 6 equivalent view of the cleaning unit of another configuration FIG. 6 equivalent view of the cleaning unit of another configuration Enlarged front view of the cleaning part of another configuration XIV-XIV cross-sectional view of FIG. FIG. 6 equivalent view of the cleaning unit of another configuration FIG. 6 equivalent view of the cleaning unit of another configuration Explanatory drawing of the shaping | molding method of the base-material part by a 1st metal mold | die Explanatory drawing of the molding method of a soft part by the 2nd metallic mold (a) is explanatory drawing just before shaping | molding of a soft part by a 2nd metal mold | die, (b) is explanatory drawing immediately after shaping | molding of a soft part by a 2nd metal mold | die. Explanatory drawing of the 2nd metallic mold of other composition Explanatory drawing of the 2nd metallic mold of other composition Explanatory drawing of the 2nd metallic mold of other composition Explanatory drawing of the 2nd metallic mold of other composition (A)-(c) is explanatory drawing of the edge part shape of a connection pin Explanatory drawing of how to find the maximum depth of the core base material recess

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<Interdental cleaning tool>
The interdental cleaning tool of this invention is equipped with the base material part which consists of synthetic resins, and the soft part which consists of elastomers.

  Synthetic resin materials constituting the substrate part include polypropylene (PP), polybutylene terephthalate (PBT), polyethylene, polyethylene terephthalate, polycyclohexylene dimethylene terephthalate, saturated polyester resin, polymethyl methacrylate, cellulose propionate, heat Thermoplastic synthetic resin materials such as plastic polyurethane, polyamide, polycarbonate, and ABS (acrylonitrile / butadiene / styrene) can be employed. Moreover, as a synthetic resin material which comprises a base material part, in order to improve productivity, it is preferable to employ | adopt the thermoplastic synthetic resin material which has crystallinity whose melting | fusing point is 150 degreeC or more. In particular, polypropylene (PP), polybutylene terephthalate (PBT), and polyamide (PA) are preferable because they can prevent the base material 10 from being broken. Polypropylene has a low molding temperature, shortens the cycle time, and improves productivity. It is most preferable because it is possible and the heat load on the molding equipment is small.

  For synthetic resin materials that make up the base material part, powder such as plate-like or granular glass flakes, mica, talc, etc. to prevent breakage of the cleaning part during insertion between teeth or during interdental cleaning Alternatively, a fiber material such as glass fiber, carbon fiber, or aramid fiber can be added.

  Examples of the elastomer constituting the soft part include thermoplastic elastomers such as styrene, olefin, and polyamide, nylon elastomers such as 6 nylon, 6-6 nylon, 6-10 nylon, and 6-12 nylon, and silicon rubber. Thermosetting elastomers such as urethane rubber, fluoro rubber, natural rubber, and synthetic rubber can be used. In particular, a material having compatibility with the synthetic resin material constituting the base portion is preferable. For example, when the base portion is made of polypropylene, the soft portion is preferably made of a polyolefin-based elastomer or a styrene-based elastomer. . In addition, what added the additive can also be employ | adopted as an elastomer.

Next, a specific shape of the interdental cleaning tool 1 will be described with reference to the drawings.
As shown in FIG. 1 to FIG. 8, the interdental cleaning tool 1 is provided with a cleaning unit 2 for interdental cleaning and a handle unit 3 as a handle when distinguished by its function. A base material portion 10 made of a synthetic resin and a soft portion 20 made of an elastomer are provided. As shown in FIGS. 1 to 3, the interdental cleaning tool 1 is manufactured in the form of an interdental cleaning tool coupling body 5 formed by connecting a plurality of interdental cleaning tools 1 in a detachable manner in parallel. A user cuts off the interdental cleaning tool 1 in order from the one side of the interdental cleaning tool connector 5 and sequentially uses it. In addition, in FIG. 1, although the 10 interdental cleaning tools 1 were connected in parallel and the interdental cleaning tool coupling body 5 was comprised, the connection number of the interdental cleaning tools 1 can be set arbitrarily.

(Base material part)
The base material portion 10 is made of a thermoplastic synthetic resin, and as shown in FIGS. 1 to 6, a flat and slender plate-like handle base material portion 11 constituting the handle portion 3, and a tip portion of the handle base material portion 11. Are provided with an elongated shaft-shaped core base material portion 12 and a connecting portion 13 for detachably connecting adjacent handle base material portions 11.

  The handle base material portion 11 is formed in a flat and slender plate shape. However, any shape other than the flat and slender plate shape, for example, a cross-sectional shape may be a circle or the like as long as it is easy to clean between teeth by picking with a finger. Oval shape (elliptical, oval, rounded rectangle, egg shape, oval shape, saddle shape, etc.) or a teardrop shape or polygonal shape, or a curved or recessed portion on the handle base It can also be provided to improve ease of use. The distal end portion of the handle base material portion 11 is configured so as to narrow toward the core base material portion 12 side, and is smoothly connected to the core base material portion 12. The handle base material portion 11 can be set to any size as long as it is easy to clean between the teeth by picking with a finger. In the handle base material portion 11 shown in FIGS. 1 and 2, for example, the length L1 is 10 mm. To 25 mm, the width W1 is set to 4 mm to 8 mm, and the thickness t1 of the grip portion is set to 1.0 mm to 2.0 mm. As described above, since the handle base material portion 11 is thin, when the base material portion 10 is molded, it is possible to reduce dimensional variations due to the shrinkage of the handle base material portion 11 and to prevent sinking. The poor loading of the base material part 10 to the second molds 40 and 41 (see FIG. 18) for forming the part 20 can be prevented.

  The core base material portion 12 is formed in a substantially straight and elongated shaft shape, and the handle base material portion 11 and the core base material portion 12 are arranged in substantially the same axis, and the core base material portion 12 and the handle base material portion 11 are arranged. Are arranged in the same plane. An exposed portion 12a that is exposed to the outside is formed on the gripping portion side of the core base material portion 12, and a core body 12b that can be inserted between teeth is formed on the tip side portion of the core base material portion 12 by being covered with an elastomer. The core base material portion 12 is formed in a gently tapered shape that decreases in diameter as it goes to the tip side.

  The length L2 of the exposed portion 12a of the core base material portion 12 from the end point of the round (curved portion) on the side surface of the distal end portion of the handle base material portion 11 configured to be narrow to the base end portion of the covering portion 21a of the soft portion 20 Is set to, for example, 10 mm to 40 mm, preferably 10 mm to 25 mm in consideration of operability, and the length L3 of the cleaning soft portion 21 is set to, for example, 12 mm to 22 mm in consideration of cleanability between the teeth. ing. From the viewpoint of ease of insertion and stress concentration, the cross-sectional shape of the core base material portion 12 is preferably circular, but may be a cross-sectional shape such as an oval shape, a teardrop shape, or a polygonal shape.

  The angle θ1 formed by the taper shape of the outer surface of the core base material portion 12 with respect to the center line of the core base material portion 12 is set to 0.2 ° to 1.5 ° in consideration of the insertability between teeth. . The diameter of the distal end side portion of the core body 12b is set to 0.4 mm to 0.6 mm, the diameter of the base end portion of the core body 12b is set to 0.8 mm to 2.0 mm, and the covering of the cleaning soft portion 21 is performed. The diameter D at the end of the curved surface of the distal end portion of the portion 21a is set to 0.5 to 1.2 mm, and the distal end side portion of the core body 12b at least 5 mm or more can be reliably inserted between the teeth from the distal end portion of the core body 12b. It is configured as follows.

  However, the angle θ1 formed by the taper shape of the core base material portion 12 is set to the same angle θ1 over the entire length of the core base material portion 12, but continuously or stepwise as it goes to the tip side of the core base material portion 12. It can also be set to be smaller. Alternatively, the exposed portion 12a may be formed in a shaft shape having the same diameter over the entire length, and only the core body 12b may be formed in a gently tapered shape that decreases in diameter toward the distal end side. Further, it is possible to omit the exposed portion 12a and connect the core body 12b directly to the handle base material portion 11.

  In the present embodiment, the present invention is applied to the I-type interdental cleaning tool 1 in which the center line extending in the longitudinal direction of the handle base material portion 11 and the axis of the core base material portion 12 are arranged in substantially the same axis. However, the present invention can also be applied to an interdental cleaning tool in which the center line of the handle base material portion 11 and the axis of the core base material portion 12 are arranged in an arbitrary positional relationship, for example, the center of the handle base material portion 11 The present invention can also be applied to an interdental cleaning tool in which the wire and the axis of the core base material portion 12 are arranged in parallel with a space therebetween, and the center line of the handle base material portion 11 is used as the axis of the core base material portion 12. On the other hand, for example, the present invention can be applied to a so-called L-shaped interdental cleaning tool provided with an angle of 120 °.

  As shown in FIGS. 2 to 4, the connecting portion 13 is integrally formed with the handle base material portion 11 between the adjacent handle base material portions 11, and the base end side and the tip end side of the handle base material portion 11 are formed. One pair is provided at intervals in the longitudinal direction. The connecting portion 13 is elongated in the length direction of the handle base material portion 11 and is formed in a trapezoidal shape (isosceles trapezoidal shape in FIG. 3) in a front view. The number of the connecting portions 13 can be arbitrarily set, and it is possible to provide only one. However, when configured as such, the connection strength of the adjacent base material portions 10 is sufficient when the interdental cleaning tool 1 is manufactured. After the base material portion 10 is molded, the connecting portion 13 is broken when the mold is opened, the base material portion 10 is broken, the soft portion 20 cannot be formed, or the connecting portion 13 is bent. Thus, the base material part 10 cannot be loaded at an appropriate position in the second molding space 42 (see FIG. 18) for molding the soft part 20, and a molding defect may occur. It is preferable to provide two or more at intervals in the length direction.

  The cross section of the connecting portion 13 is formed in a trapezoidal shape or a triangular shape (in FIG. 4, an isosceles trapezoidal shape or an isosceles triangular shape), and as shown by a virtual line in FIG. Bending the cleaning tool 1 in the direction of overlapping each other, concentrating the bending force on the boundary portion 13a, and the arcuate side surface 11a of the side edge of the handle base material portion 11 contacting the outer surface of the connecting portion 13, By applying a large force in the direction of pulling away from the boundary portion 13a according to the principle of leverage, the interdental cleaning tool 1 can be cleanly separated without significant deformation of the connecting portion 13 in the boundary portion 13a. It is configured. However, the shape of the connecting portion 13 is arbitrary as long as it can be easily and cleanly separated by bending the adjacent interdental cleaning tool 1 in the direction of overlapping each other with the connecting portion 13 as the center. It can be formed in the shape of

  Moreover, when adding a fiber material to the synthetic resin material which comprises the base material part 10, a fiber material is orientated so that the length direction may turn into the direction along the length direction of the base material part 10. Preferably, the bending strength of the base member 10 and the buckling strength with respect to the axial direction can be improved, and the core base member 12 can be folded or seated when the interdental cleaning tool 1 is used. Bending can be effectively prevented.

(Soft part)
As shown in FIGS. 1 to 6, the soft portion 20 is formed by using an elastomer material so as to be integrated with the base material portion 10, and includes a cleaning soft portion 21 that is externally mounted on the core base material portion 12. ing. However, as the soft portion 20, it is also possible to provide an annular insertion restricting portion for restricting insertion between teeth at the proximal end portion of the core body 12b, or to provide a non-slip portion on the handle base portion 11. . The insertion restricting portion and the non-slip portion can be formed independently of the cleaning soft portion 21, but the mold structure becomes complicated, so that the insertion restricting portion and the anti-slip portion are formed so as to continue to the base of the cleaning soft portion 21. Is preferred.

  The cleaning soft portion 21 includes a covering portion 21a covered by the core base material portion 12 and a plurality of cleaning protrusion portions 21b formed on the covering portion 21a so as to protrude outward at intervals in the length direction. Have.

  If the wall thickness of the covering portion 21a is too thick, it is necessary to reduce the diameter of the core body 12b covered with the covering portion 21a. Therefore, the rigidity of the cleaning portion 2 at the time of insertion between teeth is greatly reduced. In addition, it is not preferable because Karman vortices are likely to occur during molding of the cleaning soft portion 21 or may be greatly affected by Karman vortices, and if it is too thin, it is not preferable because the elastomer material cannot be filled up to the base end portion of the cleaning portion 2. . For this reason, it is preferable to set the thickness of the covering portion 21a to 0.1 mm to 0.2 mm.

  The cleaning protrusions 21b are formed at intervals in the length direction of the covering portion 21a, and are disposed at intervals in the circumferential direction of the covering portion 21a. More specifically, a pair of cleanings projecting from the covering portion 21a to one side of the mold opening / closing direction in the circumferential direction of the covering portion 21a so as to be molded by the second molds 40 and 41 described later. Projecting portion 21b, a pair of cleaning projecting portions 21b projecting from the covering portion 21a to the other side in the mold opening and closing direction, and projecting from the covering portion 21a to one side along the mating surfaces 40a and 41a. There are a total of six types of cleaning protrusions 21b, one cleaning protrusion 21b and one cleaning protrusion 21b protruding from the covering portion 21a to the other side along the mating surfaces 40a and 41a. A plurality of types of cleaning protrusions 21b of a kind are formed at intervals in the length direction of the covering portion 21a.

The cross-sectional area, length, number, and arrangement interval of the base end portion of the cleaning projection 21b can be arbitrarily set, but the base end portion of the cleaning projection 21b is considered in consideration of moldability and cleanability. the cross-sectional area of ^preferably set to about 0.03 mm 2 1.5 mm ^2, the length of the cleaning projections 21b is preferably set to approximately 0.5 mm to 2.0 mm, cleaning projections The number of 21b is preferably set to 20 to 100, and the arrangement interval of the cleaning projections 21b is preferably set to 0.5 mm to 1.5 mm. Moreover, although the cone-shaped thing was employ | adopted as the projection part 21b for cleaning, the flat taper-shaped thing flat in an axial direction is also employable. Furthermore, as the cross-sectional shape of the cleaning protrusion 21b, an arbitrary cross-sectional shape such as an oval shape, a teardrop shape, or a polygon shape can be adopted in addition to a circular shape.

  However, the cleaning protrusions 21b can be formed in an arrangement pattern other than those described above. For example, like the cleaning soft part 21G in the soft part 20G of the cleaning part 2G shown in FIG. It is also possible to provide a set of four cleaning protrusions 21Gb protruding outward in a cross shape in the axial direction. The size and shape of each part of the cleaning protrusion 21Gb can be configured in the same manner as the cleaning soft part 21, or can be configured in different dimensions and shapes.

  By the way, when the soft portion 20 is molded, the core base material portion 12 is positioned in the central portion of the second molding space 42 by a plurality of holding pins 50 to 52 provided in the second molds 40 and 41 as will be described later. Cleaning to form a core base part recess 14a in the core base part 12 through the covering part 21a at a position corresponding to the holding pin in the cleaning part 2 of the interdental cleaning tool 1 for holding. A partial recess 14 is formed. The core base part recess 14a is softened when the relatively high temperature base part 10 immediately after being molded by the first molds 30 and 31 is exposed to the heat of the elastomer filled in the second molds 40 and 41. The tip of the holding pin comes into contact with the softened core base material portion 12.

  As shown in FIG. 6, the maximum depth d of the core base part recess 14 a from the outer peripheral surface of the core base part 12 is determined when the cleaning part 2 is inserted between the teeth or during interdental cleaning by the cleaning part 2. In order to prevent a large concentration of stress from occurring at the formation position of the core base portion recess 14a when bending stress acts on the cleaning portion 2, the core base portion 12 is prevented from being bent. It is set to 085 mm or less, preferably 0.01 mm or more and 0.065 mm or less. The maximum cross-sectional area of the core base material portion 12 at the position corresponding to the core base material portion recess 14a is 55.0 to the cross-sectional area of the core base material portion 12 at the position adjacent to the core base material portion recess 14a. The core base material is set to 99.6%, preferably 80.0 to 97.9%, reducing the occurrence of stress concentration in the core base portion concave portion 14a, and inserting between teeth or cleaning between teeth. It is comprised so that the bending of the part 12 can be prevented more effectively.

  The front shape of the cleaning portion recess 14 is formed in the same shape as the pin tip shape of the holding pin, and is formed in, for example, a circular shape, an oval shape, a teardrop shape, a polygonal shape such as a square shape or a rectangular shape. The plurality of cleaning portion recesses 14 provided in the interdental cleaning tool 1 can be formed in the same shape, or can be mixed in any combination of different shapes depending on the distance from the tip of the cleaning portion 2 and the like. You can also

  When the cleaning unit recess 14 is formed in an elongated shape such as an oval shape, a teardrop shape, or a rectangle, the rectangular cleaning unit recess 14A is adjacent to the circumferential direction as in the cleaning unit 2A shown in FIG. It is preferable to form between the cleaning protrusions 21b such that the longitudinal direction is the axial direction of the cleaning portion 2A. If comprised in this way, the width | variety of 14 A of cleaning part recessed parts will be narrowed, the holding | maintenance property of the holding | maintenance pin with respect to the core base material part 12 will be ensured sufficiently, reducing the width | variety of a holding | maintenance pin. This is preferable because the stress generated at the position where the core base portion recess 14Aa is provided can be reduced.

  As shown in FIG. 6, it is preferable that the bottom surface of the core base portion recess 14a of the cleaning portion recess 14 is a flat surface in a direction perpendicular to the depth direction of the core base portion recess 14a. Like the core base part recess 14Ba of the cleaning part recess 14B shown, it is configured by an arc surface along the outer surface of the core base part 12, or like the core base part recess 14Ca of the cleaning part recess 14C shown in FIG. In addition, it can be constituted by two inclined surfaces having an isosceles triangular shape with a raised central portion.

The opening area of Shinmotozai section recess 14a is can be arbitrarily ^set, 0.08mm ^{2 ~0.35mm 2,} it is preferable that preferably set to 0.1mm ² ~0.25mm ^2. Further, the total area of Shinmoto material portion recess 14a formed in one interdental cleaner 1 is preferably set to 0.9mm ² ~1.3mm ^2. The opening area of the core base material recess 14a can be set to the same size, but is preferably set to be smaller as the core base material recess 14a on the tip side of the core base material 12 is smaller. The opening area of the core base material recess 14a refers to the core exposed in the core base material recess 14a with respect to the surface orthogonal to the center line DL (see FIG. 25) in the depth direction of the core base material recess 14a. It means the area surrounded by the projected figure of the boundary line between the base material part 12 and the cleaning soft part 21.

  A plurality of the cleaning unit recesses 14 are provided on the first side and the second side of the cleaning unit 2 at intervals in the axial direction of the cleaning unit 2. Here, the first side portion and the second side portion of the cleaning unit 2 are a part of the cleaning unit 2 molded by the second mold 40 and a part of the cleaning unit 2 molded by the second mold 41. This means the front surface side half and the back surface side half of the cleaning unit 2 corresponding to the front surface side and the back surface side of the flat handle base material portion 11.

  In the cleaning part 2 shown in FIGS. 5 and 6, the first side part and the second side part cleaning part recesses 14 face each other across the core base material part 12 and the depth direction is the second mold 40. A pair of cleaning portion recesses 14 arranged so as to be in the mold opening / closing direction of 41 and facing each other is set as one set, and three sets of cleaning portion recesses 14 are provided at intervals in the axial direction of the cleaning unit 2. It has been. It is preferable that the number of sets of the cleaning portion recesses 14 is two or more, preferably three or more. Thus, the bending stress which acts on the cleaning part 2 at the time of the insertion between teeth or the cleaning between teeth can be disperse | distributed by comprising the number of groups of the cleaning part recessed part 14 to 3 sets or more or 4 sets or more. In addition, as will be described later, by securing the holdability of the core base material portion 12 by the holding pins 50 to 52, by reducing the depth of the core base material portion recess 14a, it is locally large during interdental cleaning. It is possible to effectively prevent the core base material portion 12 from being bent due to the bending stress.

  At least one of the plurality of cleaning portion recesses 14 paired with the first side portion and the second side portion has a central line segment in the depth direction passing through the center of the cleaning portion recess portion 14. The circumferential direction of the cleaning unit 2 is formed at an angle with respect to the mold opening / closing direction of the second molds 40 and 41 for molding the part 21. Specifically, in the cleaning unit 2 shown in FIG. 5, the second second cleaning unit recess 14 counted from the front end of the cleaning unit 2 has an angle θ2 with respect to the mold opening / closing direction as shown in FIG. 6. The first pair of first cleaning section recesses 14 and the third pair of third cleaning section recesses 14 provided at an angle and counted from the front end of the cleaning section 2 are shown in FIG. As shown in FIG. 2, the center line segments extending in the depth direction are provided so as to be disposed in the mold opening / closing direction of the second molds 40 and 41, respectively.

  When the angle θ2 with respect to the mold opening / closing direction exceeds 60 °, the holding pins (see FIG. 20) provided in the adjacent cleaning soft part molding portions 46 may interfere with each other, and therefore, 60 ° or less, preferably 45 It is preferable to set the angle below. However, like the cleaning unit 2F shown in FIG. 15, the cleaning unit recess 14F can be formed with an angle θ2 on the opposite side across a line segment in the mold opening / closing direction passing through the center of the cleaning unit 2.

  The cleaning unit recess 14 with the angle θ2 and the cleaning unit recess 14 arranged in the mold opening / closing direction can be arbitrarily combined to form the cleaning unit 2, or all the cleaning unit recesses 14 of the cleaning unit 2 can be formed. In addition, the cleaning portion recess 14 with an angle θ2 may be used. In addition, when two or more sets of the cleaning unit recesses 14 with the angle θ2 are provided, the angles θ2 can be set to the same angle, or a part can be set to the same angle and the rest can be set to different angles. Or all at different angles.

  In this way, when the cleaning section recess 14 having the angle θ2 is provided in the cleaning section 2, the cleaning section recess 14 is formed in an empty space corresponding to the layout of the cleaning projection 21b so that the number is not reduced as much as possible. The cleaning protrusion 21b can be formed. That is, the cleaning portion recess 14 is formed by the holding pins 50 to 52 of the second molds 40 and 41 that hold the core base material portion 12 in the center portion of the second molding space 42 as described above. The cleaning projection 21b cannot be formed. On the other hand, the cleaning protrusion 21b is formed on the mating surface of the second molds 40, 41 in consideration of the releasability from the second molds 40, 41, or the mold of the second molds 40, 41. Since the holding pins are arranged in the mold opening / closing direction of the second molds 40 and 41, the cleaning protrusions 21b corresponding to the holding pins must be omitted. Specifically, it is necessary to omit both of the two cleaning protrusions 21b disposed adjacent to each other in the mold opening / closing direction at the position corresponding to the holding pin. On the other hand, when the cleaning portion concave portion 14 with the angle θ2 is provided, as shown in FIG. 7, one of the two cleaning protrusions 21b arranged adjacent to each other in the mold opening / closing direction is omitted, and the other is Since it can leave, the number of the protrusion parts 21b for cleaning can be increased as much as possible, and the interdental cleaning property can be improved. Further, depending on the layout of the cleaning protrusions 21b, all the cleaning protrusions 21b can be left. Further, when the four cleaning protrusions 21Gb are arranged in a cross shape like the cleaning part 2G shown in FIG. 16, the cleaning is performed with an angle θ2 between the cleaning protrusions 21Gb adjacent in the circumferential direction. By forming the recess 14, all the cleaning protrusions 21 </ b> Gb can be arranged in a cross shape without omitting the cleaning protrusion 21 </ b> Gb.

  Further, in the I-type interdental cleaning tool 1 having a flat handle portion 3 as shown in FIG. 2, the bending direction of the cleaning portion 2 at the time of cleaning between molars is generally determined, and FIG. As indicated by the line, the cleaning portion 2 is basically curved in a plane that passes through the axis of the cleaning portion 2 and is orthogonal to the plane including the flat handle portion 3. By adjusting the position of the core base part recess 14a in the circumferential direction of the core base part 12 so that the cleaning part recess 14 is not disposed, the stress concentration at the position of the core base part recess 14a is suppressed, It is possible to effectively prevent the cleaning part 2 from being broken at the position of the core base part recess 14a. Moreover, since a large bending load acts on the cleaning portion 2 at a position of 5 to 6 mm from the distal end portion during cleaning between molars, the second cleaning concave portion 14 from the distal end portion of the cleaning portion 2 is angled. By constituting the cleaning recess 14 with θ2, it is possible to effectively prevent the cleaning portion 2 from being broken around the second cleaning recess 14.

  In addition, the arrangement | positioning space | interval of the cleaning part recessed part 14 with respect to the axial direction of the cleaning part 2 can be set so that it may become substantially uniform or narrow as it goes to the front end side of the cleaning part 2. FIG. The distal end portion of the cleaning portion 2 is a substantially linear elongated shaft-like structure configured to have a smaller diameter than the base end portion, and is structurally easily changed with respect to the molding pressure when the cleaning soft portion 21 is molded. Therefore, if the arrangement interval of the cleaning portion recesses 14 is set so as to become narrower toward the front end side of the cleaning portion 2 or is set to be substantially uniform, the core base material portion 12 is formed when the soft portion 20 is formed. It is easy to suppress the movement from the predetermined position. In particular, it is the most preferred embodiment that the arrangement interval of the cleaning unit recesses 14 with respect to the axial direction of the cleaning unit 2 is set to a substantially uniform interval. If comprised in this way, the external force which the core base material part 12 receives at the time of shaping | molding of the soft part 20 tends to become uniform, and is more preferable.

  In addition, as shown in FIG. 6, the pair of cleaning portion recesses 14 is preferably arranged on the same axis line as the first side cleaning portion recess 14 and the second side cleaning portion recess 14. As in the cleaning part recess 14D of the cleaning part 2D shown in FIG. 12, the center line of the cleaning part recess 14D on the first side and the center line of the cleaning part recess 14D on the second side are in the radial direction of the cleaning part 2D. It is also possible to form the cleaning portion recess 14D so as to be arranged in parallel with a certain distance.

  Moreover, the arrangement | positioning position of the cleaning part recessed part 14 with respect to the cleaning part 2 can also be comprised as follows. However, the cleaning part recess 14E and the core base part recess 14Ea are different from the cleaning part recess 14 and the core base part recess 14a only in the formation position with respect to the cleaning part 2, and the front shape, depth, and opening area are The cleaning portion recess 14 and the core substrate portion recess 14a can be configured in the same manner.

  The same as counted from the front end of the cleaning part 2E corresponding to the cleaning part concave part 14E on the first side part, like the cleaning part concave part 14E and the core base part concave part 14Ea of the cleaning part 2E shown in FIGS. The cleaning part recess 14 </ b> E on the second side can be formed at an interval in the axial direction of the cleaning part 2 </ b> E so as not to overlap in the circumferential direction of the cleaning part 2 </ b> E. In FIG. 13, the cleaning portion recess 14 </ b> E of the second side portion is disposed at a substantially central portion between the adjacent cleaning portion recesses 14 </ b> E on the first side portion, but the tip between the adjacent cleaning portion recesses 14 </ b> E on the first side portion. It can also comprise so that the cleaning part recessed part 14E of a 2nd side part may be arrange | positioned in the position biased to the side or the base end side. In addition, the cleaning unit recesses 14E on the first side and the cleaning unit recesses 14E on the second side are spaced apart from each other in the circumferential direction of the cleaning unit 2E in the axial direction of the cleaning unit 2E. The cleaning portion recess 14E on the first side and the corresponding cleaning portion recess 14E on the same second side counted from the tip of the cleaning portion 2E can be cleaned. It can also be formed with an interval in the axial direction of the cleaning part 2E so as not to overlap in the circumferential direction of the part 2E. Further, the number of the cleaning part recesses 14E on the first side part and the number of the cleaning part recesses 14E on the second side part are preferably the same number, but can also be different, for example, cleaning the first side part. The number of the concave portions 14E can be made one less than the number of the cleaning portion concave portions 14E on the second side portion.

  In this way, the core base portion recesses 14Ea are alternately formed on the first side portion and the second side portion of the core base portion 12, and a pair of core bases are formed at the same position in the axial direction of the core base portion 12. Since it can prevent that a material part recessed part is formed, the cross-sectional area of the core base material part 12 in the position corresponding to the core base material part recessed part 14Ea can be enlarged, and generation | occurrence | production of the bending of the core base material part 12 can be prevented. Further, when the core portion 1 is bent between the holding pins 50A to 52A (see FIG. 18) when the soft portion 20 is molded, the depth of the core portion recess 14Ea is not easily increased. The cross-sectional area of the core base material portion 12 at the position corresponding to the material portion concave portion 14Ea is increased, and the occurrence of breakage of the core base material portion 12 can be prevented. Furthermore, since the distance between the holding pins 50A to 52A of the second mold 40 and the holding pins 50A to 52A of the second mold 41 with respect to the length direction of the core base 12 is shortened, the core base is stable. It becomes possible to hold it with good performance.

<Manufacturing method>
Next, the manufacturing method of an interdental cleaning tool is demonstrated.
As shown in FIGS. 17 to 19, this interdental cleaning device manufacturing method is a base material for manufacturing the base material portion 10 by filling the first molding space 32 of the first mold 30, 31 with a synthetic resin material. After the base part 10 formed by the part molding process and the first molds 30 and 31 is set in the second molding space 42 of the second molds 40 and 41, the second molding space 42 is filled with an elastomer material. And a soft part forming step for forming the soft part 20. The first molds 30 and 31 correspond to the first mold and the second mold of the first mold, respectively, and the second molds 40 and 41 correspond to the first mold and the second mold of the second mold, respectively. To do.

(Base part molding process)
In the base material portion molding step, as shown in FIG. 17, the base material portion 10 is manufactured by filling the first molding space 32 of the first molds 30 and 31 with a synthetic resin material. More specifically, as the first molds 30 and 31, a plurality of first molding spaces 32 composed of a core base material portion molding portion 32a and a handle base material portion molding portion 32b are formed in parallel, and adjacent handle bases are formed. A pair of connecting portion molding portions 35 communicating with the material portion molding portion 32 b are formed, and a runner 33 is formed on the proximal end side of the plurality of first molding spaces 32, and a plurality of first portions are formed through the gate 34. By using the molding space 32 communicating with the runner 33 and supplying the synthetic resin material to the runner 33, the plurality of first molding spaces 32 are filled into the plurality of first molding spaces 32 through the gates 34. 10 will be molded simultaneously. Then, a primary molded product 10 </ b> A having a plurality of base material parts 10, runner parts 37, gate parts 36 and connecting parts 13 is manufactured. In addition, although the base material part 10 can also be shape | molded one by one, while shape | molding the several base material part 10 simultaneously, productivity can be improved and the shape | molded runner part 37 is hold | maintained. It is preferable because a plurality of substrate parts 10 can be transferred simultaneously and workability can be improved. The gate 34 is formed on the base end portion of the first forming space 32 opposite to the core base portion forming portion 32a, more preferably, the core base portion forming the first forming space 32 than the connecting portion forming portion 35. If it is the base end side opposite to the portion 32a, it can be formed at an arbitrary position. However, if a side gate is formed as the gate 34 at the base end portion of the first molding space 32, the second die 40 is formed. , 41 when the primary molded product 10A is loaded, it is preferable because the risk of the gate portion 36 of the primary molded product 10A being sandwiched between the second molds 40, 41 can be reduced. In addition, a hot runner can be provided in the first mold 30, 31 in place of the runner 33 made of a cold runner. However, the first mold 30, 31 is large and the manufacturing cost is high. It is preferable to provide a runner 33 made of a cold runner. Further, since the plurality of base material parts 10 can be connected with stability by the runner part 37, when the primary molded product 10A is transferred to the second molds 40 and 41, the handling property of the primary molded product 10A can be improved. preferable. Further, if a pin gate having a cylindrical shape or a spindle shape and having a diameter of 0.1 to 1.5 mm is adopted as the gate 34, a cold runner can be adopted, and the molded product can be made compact by narrowing the interval between the gates 34. It is preferable because it is possible.

(Soft part molding process)
In the soft part molding step, as shown in FIGS. 18 and 19, after setting the primary molded product 10A molded by the first molds 30, 31 in the second molding space 42 of the second molds 40, 41, The soft material 20 is formed by filling the second molding space 42 with an elastomer material, and the interdental cleaning tool connector 5 in which a plurality of interdental cleaning tools 1 are arranged in parallel is obtained.

  First, the second molds 40 and 41 used in the soft part molding step will be described. The second molds 40 and 41 include a plurality of base material parts of the primary molded product 10A molded by the first molds 30 and 31. A plurality of second molding spaces 42 are formed at positions corresponding to 10, and fitting spaces 43, 44, 45 that fit the runner portion 37, the plurality of gate portions 36, and the connecting portion 13 of the primary molded product 10 </ b> A are provided. Is formed. Between the second molds 40, 41 and the base material part 10, a cleaning soft part molding part 46 surrounding the core base material part 12 is formed as a second molding space 42. Gates 47 are formed on the mating surfaces 40a and 41a with the second molds 40 and 41 on the front end side of the cleaning soft portion molding portion 46, respectively. The gate 47 is connected to a common runner 48 formed in the second molds 40, 41, and the elastomer material is supplied from the common runner 48 to the plurality of second molding spaces 42 through the plurality of gates 47. Has been. The diameter of the gate 47 is preferably set to 0.1 mm or more and 1.0 mm or less.

  The second molds 40 and 41 have a pair of distal-end-side holding pins 50 and a pair of intermediate-portions held in correspondence with the distal-end side portion, intermediate portion, and proximal-end portion of the cleaning soft portion molding portion 46, respectively. A pin 51 and a pair of proximal end holding pins 52 are provided in a face-to-face manner. The distal end side holding pin 50 and the proximal end side holding pin 52 are movable in a direction substantially orthogonal to the mating surfaces 40a, 41a of the second molds 40, 41, in other words, in the mold opening / closing direction of the second molds 40, 41. As shown in FIG. 20, the midway holding pin 51 is provided in a face-to-face manner so that its center line is arranged at an angle θ2 with respect to the mold opening / closing direction. As shown in FIG. 19 (b), the core base material portion 12 of the base material portion 10 projects the tip portions of these three sets of holding pins 50 to 52 into the cleaning soft portion molding portion 46, and sets each set. The core base material portion 12 is sandwiched between the tip portions of the holding pins 50 to 52 so that the center portion of the cleaning soft portion molding portion 46 is accurately positioned and held.

  The angle θ2 of the holding pin 51 can be arbitrarily set. However, when it exceeds 60 °, the holding pins 51 in the adjacent second molding space 42 may interfere with each other, and therefore, the holding pin 51 is 60 ° or less, preferably 45. It is preferable to set the angle below. However, as in the second molds 40A and 41A shown in FIG. 21, the holding pin 51 may be provided with an angle θ2 on the opposite side across the line segment in the mold opening / closing direction passing through the center of the second molding space 42. it can.

  The holding pin with the angle θ2 and the holding pin arranged in the mold opening / closing direction can be arbitrarily combined to be formed in the cleaning unit 2, and all the holding pins of the cleaning unit 2 are held with the angle θ2. Can also be configured. When two or more sets of holding pins with an angle θ2 are provided, all the angles θ2 can be set to the same angle, or some of them can be set to the same angle and the rest can be set to different angles. , All can be set at different angles.

  Thus, when the holding pin 51 is provided at a position at an angle θ2 with respect to the mold opening / closing direction, when the plurality of cleaning protrusions 21b protruding outward are formed on the cleaning soft part 21, The degree of freedom of the layout of the protruding portions 21b can be improved. That is, the holding pin 51 is formed by the holding pin 51 that holds the core base material portion 12 at the central portion of the cleaning soft portion forming portion 46, and the position of the holding pin 51 is formed on the cleaning protrusion portion 21 b. Since the cleaning soft portion molding portion 46 can be adjusted in the length direction and the circumferential direction so as not to interfere with the position, the degree of freedom of the layout of the cleaning projection 21b can be improved.

  Moreover, when the elastomer material is filled into the cleaning soft part molding portion 46, the core base material portion 12 is exposed to a high temperature elastomer material and softens, and the tip of the holding pins 50 to 52 causes the core base material portion 12 to be softened. A core base material recess 14a is formed on the outer peripheral surface. The core base part recess 14a is formed when the cleaning part 2 is inserted into the interdental space or when the cleaning part 2 performs interdental cleaning when a bending stress acts on the cleaning part 2. In some cases, the core base material portion 12 is broken due to a large concentration of stress. In particular, in the interdental cleaning tool 1 in which the handle base material portion 11 is formed flat, when the handle base material portion 11 is picked by a finger to clean the molars, the cleaning portion 2 includes a surface including the handle base material portion 11 and The holding pin 51 is formed so as to form an angle θ2 with respect to the mold opening / closing direction, although it is curved in a plane substantially perpendicular to the mold opening / closing direction. It is possible to effectively prevent the core base material portion 12 from being broken starting from the core base material recess 14a.

  The maximum depth d of the core base part recess 14a is a holding pin for the core base part 12 so that the cleaning part 2 does not break at the position of the core base part recess 14a due to bending stress during interdental cleaning. By adjusting the length of 50-52, it is preferable to set it to 0.01 mm or more and 0.085 mm or less, preferably 0.01 mm or more and 0.065 mm or less.

  In addition, the cross-sectional area of the cross-section orthogonal to the axial direction of the front end portions of the holding pins 50 to 52 is substantially the same as each other, or the cross-section of the front end portion of the holding pin in which the holding pin 50 positioned at the most front end is in another position Small compared with the cross-sectional area of. The intermediate portion holding pin 51 and the proximal end side holding pin 52 are substantially the same or configured so that the intermediate portion holding pin 51 is larger than the proximal end side holding pin 52. That is, since the passage area of the distal end portion of the cleaning soft portion molding portion 46 is reduced, the flow resistance of the elastomer material is set as small as possible by reducing the cross-sectional area of the distal end holding pin 50 as much as possible. Suppressing the influence of the Karman vortex that is sometimes generated is preferable because it is possible to prevent defective filling of the elastomer material into the cleaning soft part molding portion 46 and to prevent excessive melting of the core base material portion 12. However, the cross-sectional areas of the holding pins 50 to 52 can be set to be the same. Further, a plurality of intermediate portion holding pins 51 can be provided at intervals in the axial direction. In the present embodiment, the cross-sectional shape of the tip of the holding pins 50 to 52 is circular, but in order to further suppress the influence of Karman vortices during molding, in the length direction of the cleaning soft part molding part 46 It is also possible to form an elongated oval shape, a teardrop shape, a rectangular shape, or the like.

Tip-side holding pin 50 is provided in the range of 3mm toward the distal end 46a of the cleaning soft portion forming portion 46 toward the proximal end, a cross-sectional area is set to 0.03mm ² ~0.3mm ² Yes. The intermediate portion holding pin 51 is provided within a range of ± 10% of the length of the cleaning portion 2 in the axial direction around the middle point between the distal end side holding pin 50 and the proximal end side holding pin 52, and its cross-sectional area. It is set to 0.12mm ² ~1.2mm ^2. Further, the proximal retaining pin 52 is set from the proximal end of the cleaning soft portion molding portion 46 provided in the range of 6mm toward the distal end side, a cross-sectional area to 0.1mm ² ~1.1mm ² Has been. By setting these, it is expected that not only the core base material portion 12 is fixed during molding, but also the influence of Karman vortices generated during molding on the molded body is prevented.

  The front end surface of the holding pins 50 to 52 that is in contact with the core base material portion 12 is configured as a flat surface orthogonal to the axial direction of the holding pins 50 to 52 as shown in FIG. Like the holding pin 60 shown in (b), it is configured by an arcuate surface along the outer peripheral surface of the core base material portion 12, or is connected in an isosceles triangular shape like the holding pin 61 shown in FIG. It is also possible to configure with a pair of inclined surfaces, and when configured in this way, the contact area between the core base material portion 12 and the holding pins 60 and 61 is set large, This is preferable because the depth can be set shallow, the core base material portion 12 can be held in the center of the second molding space 42 with high accuracy, and the holdability of the core base material portion 12 can be improved. In addition, holding pins having different tip end surface shapes can be used in any combination.

  The pair of distal end side holding pins 50, the pair of intermediate portion holding pins 51, and the pair of proximal end side holding pins 52 are arranged in a face-to-face manner on the same axis line with the core base material part 12 interposed therebetween. At least one set of the holding pins 50 to 52 is shifted in the length direction of the cleaning soft part molding portion 46 by, for example, a length of 0.1 to 1.0 times the diameter of the proximal holding pin 52. Can be arranged. If the pair of holding pins 52 are arranged so as to be shifted in the longitudinal direction of the cleaning soft part forming portion 46 in this way, when the core base material portion 12 is held between the holding pins 52, Since the area of the holding pin 52 to be crimped is effectively increased, the core base material portion 12 can be held more firmly. Moreover, it can be expected to prevent the Karman vortex generated during molding from affecting the molded body.

  In the soft part molding step, as shown in FIG. 19A, the primary molded product 10A is set in the second molding space 42 and the mold is closed, as shown in FIG. The side holding pin 50, the pair of intermediate portion holding pins 51, and the pair of base end side holding pins 52 are projected into the cleaning soft portion molding portion 46, and these three sets of holding pins 50 to 52 are used. An elastomer material is injected and supplied to a plurality of gates 47 through a common runner 48 while holding the core base material portion 12, and the elastomer material is filled into the cleaning soft portion molding portion 46. At this time, the core base material portion 12 is softened by the heat of the elastomer material, and the core base material portion concave portion 14a is formed by the tip portions of the holding pins 50 to 52. The maximum depth of the core base material portion concave portion 14a is formed. Since d is set to 0.01 mm or more and 0.085 mm or less, preferably 0.01 mm or more and 0.065 mm, the cleaning unit is used when the cleaning unit 2 is inserted between the teeth or when the cleaning unit 2 performs interdental cleaning. When a bending stress is applied to 2, it is possible to prevent the core base material portion 12 from being broken due to a large stress concentration at the position where the core base material recess 14 a is formed. Further, since the cross-sectional area of the holding pin 50 is set smaller than the cross-sectional area of the holding pins 51 and 52, filling of the elastomer material from the distal end portion of the cleaning soft portion molding portion 46 to the proximal end side is performed. The contact area between the holding pins 50 to 52 and the core base material portion 12 can be increased while keeping the core base material portion 12 with high stability while being prevented from being inhibited as much as possible by 50 to 52, and the injection pressure varies somewhat. Even if it occurs, it is possible to prevent the bending of the core base material portion 12 and to accurately mold the cleaning soft portion 21 made of an elastomer material.

  Thus, after covering the base portion 10 with the soft portion 20, the runner portion 37 and the gate portion 36 made of synthetic resin are removed, and the runner portion 55 made of an elastomer formed by the runner 48 and the gate 47 and The interdental cleaning tool 1 is obtained by removing the gate portion 56.

In addition, the arrangement | positioning position of the holding pins 50-52 with respect to the 2nd metal mold | dies 40 and 41 can also be comprised as follows.
Like the holding pins 50A to 52A of the second molds 40 and 41 shown in FIG. 22, the holding pins 50A to 52A of the second mold 40 are counted from the tip of the corresponding soft part molding part 46 for cleaning corresponding thereto. The holding pins 50 </ b> A to 52 </ b> A of the second second mold 41 are spaced apart in the direction of the center line of the cleaning soft part molding part 46 so as not to overlap in the circumferential direction of the cleaning soft part molding part 46. Can be formed. In FIG. 22, the adjacent holding pins 50 </ b> A to 52 </ b> A in the second mold 40 are arranged in the approximate center between the holding pins 50 </ b> A to 52 </ b> A of the second mold 41. The holding pins 50A to 52A of the second mold 40 may be arranged at positions deviated toward the front end side or the base end side between 50A to 52A. In addition, all the holding pins 50 </ b> A to 52 </ b> A of the second mold 40 and all the holding pins 50 </ b> A to 52 </ b> A of the second mold 41 are cleaned so as not to overlap in the circumferential direction of the cleaning soft part molding portion 46. It can also be formed with an interval in the length direction of the soft part molding part 46 for use, the same as the specific holding pin of the second mold 40 and the corresponding tip from the tip of the soft part molding part 46 for cleaning The holding pins of the second second mold 41 can also be formed at intervals in the length direction of the cleaning soft part molding part 46 so as not to overlap in the circumferential direction of the cleaning soft part molding part 46. Furthermore, the number of holding pins of the second mold 40 and the number of holding pins of the second mold 41 are preferably the same number, but can also be different, for example, as shown in FIG. One holding pin 52A of the mold 40 can be omitted, and the number of holding pins of the second mold 40 can be made one less than the number of holding pins of the second mold 41.

  As described above, when the holding pins 50A to 52A of the first mold 40 are arranged so as to be shifted in the axial direction with respect to the holding pins 50A to 52A of the second mold 41, compared to the case where the holding pins are arranged facing each other, Since the cross-sectional area of the core base material portion 12 at the position corresponding to the core base material portion recess 14Ea is increased, it is possible to prevent the core base material portion 12 from being broken. Further, when the soft core portion 21 for cleaning is molded, the core base material portion 12 is also bent between the holding pins 50A to 52A. The cross-sectional area of the core base material portion 12 at a position corresponding to 14Ea is increased, and the occurrence of breakage of the core base material portion 12 can be prevented. Furthermore, since the interval between the holding pins 50A to 52A with respect to the length direction of the core base material portion 12 is substantially shortened, the core base material portion 12 can be held with good stability.

  The embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and it goes without saying that the configuration can be changed without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Interdental cleaning tool 2 Cleaning part 3 Handle part 5 Interdental cleaning tool coupling body 10 Base material part 10A Primary molded article 11 Handle base material part 11a Side surface 12 Core base material part 12a Exposed part 12b Core main body 13 Connection part 13a Boundary part 14 Cleaning part recess 14a Core base part recess 20 Soft part 21 Cleaning soft part 21a Covering part 21b Cleaning projection 2A Cleaning part 14A Cleaning part recess 14Aa Core base part recess 14B Cleaning part recess 14Ba Core base part recess 14C Cleaning part recess 14Ca Core base part recess 2D Cleaning part 14D Cleaning part recess 2E Cleaning part 14E Cleaning part recess 14Ea Core base part recess 2F Cleaning part 14F Cleaning part recess 14Fa Core base part recess 2G Cleaning part 20G Soft part 21G Cleaning Soft part 21Gb Cleaning projection 30 First mold 31 First mold 32 First molding space 32a Core base part molding part 32b Handle base part molding part 33 Inner 34 Gate 35 Connecting portion forming portion 36 Gate portion 37 Runner portion 40 Second mold 40a Mating surface 41 Second mold 41a Mating surface 42 Second molding space 43 Fitting space 44 Fitting space 45 Fitting space 46 For cleaning Soft part molding part 46a Tip part 47 Gate 48 Runner 50 Tip side holding pin 51 Intermediate part holding pin 52 Base end side holding pin 55 Runner part 56 Gate part 50A-52A Holding pin 40A Second mold 41A Second mold 60 Holding Pin 61 Holding pin 62 Holding pin

Claims (9)

A base portion made of a synthetic resin, and a soft portion made of an elastomer covering at least a part of the base portion. The base portion is provided at a handle base portion and a tip portion of the handle base portion. An elongated shaft-shaped core base material portion provided continuously, and the soft portion has at least a cleaning soft portion covering the core base material portion, and the handle base portion serves as a handle. An interdental cleaning tool comprising an interdental cleaning portion with the core base material portion and the soft cleaning portion,
The cleaning soft portion is formed in each of the first side portion and the second side portion of the cleaning portion formed by the first mold and the second die of the mold for forming the cleaning soft portion, respectively. , Forming a plurality of cleaning part recesses for forming a core base part recess in the core base part at intervals in the axial direction of the cleaning part, and making a pair with the first side part and the second side part the center line in the depth direction passing through the center of some of the sets of cleaning portion recess of the plurality of sets of the cleaning portion concave with respect to the first type and opposing direction of the second type before Kikin type , Formed with an angle of 5 ° or more in the circumferential direction of the cleaning portion,
An interdental cleaning tool characterized by that. The interdental cleaning tool according to claim 1, wherein a pair of cleaning part recesses with the angle is provided at a position 5 to 6 mm from a tip part of the cleaning part in the core base material part.   The interdental cleaning tool of Claim 1 or 2 which set the said angle to 60 degrees or less.   The interdental according to any one of claims 1 to 3, wherein a plurality of sets of the cleaning portion recesses with the angle are provided, and the angles in the plurality of sets are set to different angles with each other or with any combination of cleaning unit recesses. Cleaning tool. A direction in which the first and second molds face each other , wherein the center line of the handle part and the axis of the core base part are arranged coaxially, and the handle base part can be gripped and held by a finger. The interdental cleaning tool according to any one of claims 1 to 4, wherein the interdental cleaning tool is formed in a thin and flat shape. A base portion made of a synthetic resin, and a soft portion made of an elastomer covering at least a part of the base portion. The base portion is provided at a handle base portion and a tip portion of the handle base portion. An elongated shaft-shaped core base material portion provided continuously, and the soft portion has at least a cleaning soft portion covering the core base material portion, and the handle base portion serves as a handle. And a manufacturing method of an interdental cleaning tool in which a cleaning part for interdental cleaning is configured with the core base material part and the soft cleaning part,
A base material part molding step of supplying a synthetic resin material to the first molding space of the first mold and molding the base material part;
The base material part molded in the base material part molding step is set in a second molding space of a second mold for molding the soft part, and is spaced from the second mold in the length direction of the second molding space. A plurality of holding pins that are paired with the first mold and the second mold of the second mold, so that a core base part recess is formed in the core base part. A soft part molding step of filling the second molding space with an elastomer material and molding the soft part in a state in which the core base material part is held at a substantially central part of the cleaning soft part molding part;
The provided, part of the set of the center line of the holding pins, the angle of 5 ° or more with respect to the facing direction of the second mold the first type and second type of the plurality of sets of holding pins Provided with
The manufacturing method of the interdental cleaning tool characterized by the above-mentioned. The manufacturing method of the interdental cleaning tool of Claim 6 which provided the pair of holding pins which gave the said angle corresponding to the location of 5-6 mm from the front-end | tip part of the said cleaning part among the said core base material parts. .   The manufacturing method of the interdental cleaning tool of Claim 6 or 7 which set the said angle to 60 degrees or less.   The interdental cleaning tool according to any one of claims 6 to 8, wherein a plurality of sets of holding pins with the angle are provided, and the angles in the plurality of sets are set to different angles with each other or with any combination of holding pins. Manufacturing method.

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