Toothbrush head for electric toothbrush, and manufacturing method therefor

Abstract

A toothbrush head for an electric toothbrush, and a manufacturing method therefor. The toothbrush head comprises: a brush disc (2); and a brush-head housing (1), wherein an accommodating portion (11) is formed at one end of the brush-head housing (1); the accommodating portion (11) accommodates a rotating portion (22) of the brush disc (2); a first surface (25) of the brush disc (2) rotates about an axis of rotation relative to a second surface (15) of the accommodating portion (11); one of the first surface (25) of the brush disc (2) and the second surface (15) of the accommodating portion (11) has a first surface shape formed by means of injection molding using a mold, and the other of the first surface (25) of the brush disc (2) and the second surface (15) of the accommodating portion (11) has a molded second surface shape that corresponds to the first surface shape; at least one of the first surface (25) and the second surface (15) is formed from a thermoplastic crystalline polymer; and the first surface shape and the second surface shape are formed to prevent the brush disc (2) from being separated from the accommodating portion (11) in the direction of the axis of rotation. The toothbrush head omits the step of assembling the brush disc (2) and the brush-head housing (1), thereby improving production efficiency, reducing costs, and eliminating potential safety risks caused by assembly errors.

Description

Toothbrush head for electric toothbrush and method for manufacturing the same Technical Field

[0001] The present invention relates to the technical field of oral care devices, and in particular to a toothbrush head for an electric toothbrush. Background Art

[0002] Electric toothbrushes are now widely used. A common electric toothbrush features a reciprocating brush head, which includes a handle housing and a brush disc. The brush disc is equipped with cleaning elements, and a rocker arm is located within the handle housing. The rocker arm drives the brush disc to reciprocate within a housing at one end of the handle housing, thereby achieving the cleaning action of the brush head.

[0003] In order to achieve rotational movement of the brush disc relative to the brush handle housing while ensuring that the brush disc does not separate from the brush handle housing during use, CN104825243B discloses a brush head in which the brush disc is mounted in a receiving portion of the brush handle housing via a brush disc drive shaft. The brush head drive shaft passes through a hollow area of ​​the brush disc and is attached to a hole in the brush handle housing. This ensures a reliable rotational connection of the brush disc relative to the brush handle housing.

[0004] However, the manufacturing and assembly process for the connection structure that attaches the brush disc to the housing of the handle housing in existing toothbrush heads is relatively complex. When the brush head drive shaft is made of metal, the production cost is relatively high. Furthermore, since the brush disc needs to be installed into the housing in a subsequent step, assembly errors can also pose a safety hazard, potentially causing the brush disc to detach.

[0005] Therefore, the existing reciprocating toothbrush heads still have deficiencies, and it is necessary to further simplify the production process of toothbrush heads. It is also expected that the production cost can be further reduced and the reliability of the product can be improved.

[0006] Summary of the Invention

[0007] In order to overcome the deficiencies in the prior art, the present invention provides a toothbrush head for an electric toothbrush, comprising: a brush disc, the brush disc including a rotating portion; and a brush head housing, one end of the brush head housing forming a housing portion, the housing portion receiving the rotating portion of the brush disc, the first surface of the brush disc rotating around a rotation axis relative to the second surface of the housing portion, wherein one of the first surface of the brush disc and the second surface of the housing portion has a first surface shape formed by mold injection, and the other of the first surface of the brush disc and the second surface of the housing portion has a second surface shape molded corresponding to the first surface shape; at least one of the first surface and the second surface is formed of a thermoplastic crystalline polymer, and the first surface shape and the second surface shape are formed to prevent the brush disc from escaping from the housing portion of the brush head housing along the direction of the rotation axis.

[0008] According to one aspect of the present invention, the brush plate is integrally formed of a thermoplastic crystalline polymer, and the molding shrinkage of the thermoplastic crystalline polymer is greater than 0.5%.

[0009] According to another aspect of the present invention, the brush disc also includes a cleaning element carrier portion, and the rotating portion is arranged on one side of the carrier portion; the first surface and the second surface include at least one section of a conical surface that tapers toward the cleaning element carrier portion, and the conical surface has an inclination angle greater than 0.3 degrees relative to the rotation axis.

[0010] According to another aspect of the present invention, in the direction of the rotation axis, the first surface of the brush disc includes: a first conical portion, which tapers in the direction away from the side of the brush disc to which the cleaning element is attached; and a second conical portion, which tapers in the direction toward the side of the brush disc to which the cleaning element is attached; the second surface of the brush head housing includes: a third conical portion, which tapers in the direction away from the side of the brush disc to which the cleaning element is attached and matches the first conical portion; and a fourth conical portion, which tapers in the direction toward the side of the brush disc to which the cleaning element is attached and matches the second conical portion.

[0011] According to another aspect of the present invention, the brush disc integrally includes a cleaning element carrier portion, and the rotating portion protrudes on one side of the carrier portion; the first surface of the brush disc also includes: an annular end face of the carrier portion, the annular end face is transverse to the rotation axis; the second surface of the brush head housing also includes: an end face of the accommodating portion.

[0012] According to another aspect of the present invention, the toothbrush head also includes a rocker arm that reciprocates in the brush head housing, and the rotating part is formed with a follower recess for receiving the driving end of the rocker arm, wherein the follower recess is at least partially arranged at the second conical surface part of the rotating part.

[0013] According to another aspect of the present invention, the accommodating portion further includes a peripheral wall and a bushing inside the peripheral wall, the bushing forming a second surface of the accommodating portion, and the bushing and the peripheral wall are retained by injection molding so as not to separate along the rotation axis direction.

[0014] According to yet another aspect of the present invention, the bushing is formed from a thermoplastic crystalline polymer.

[0015] According to another aspect of the present invention, the accommodating portion has a peripheral wall surrounding the rotation axis, both sides of the peripheral wall have openings, and the rotating portion of the brush disc extends from the opening on one side of the peripheral wall to the opening on the other side of the peripheral wall.

[0016] According to yet another aspect of the present invention, the thermoplastic crystalline polymer is polyoxymethylene.

[0017] In addition, the present invention also provides a method for manufacturing a toothbrush head, which includes a brush disc, the brush disc including a cleaning element carrier portion and a rotating portion protruding on one side of the carrier portion; and a brush head shell, one end of the brush head shell forms a receiving portion, the receiving portion receives the rotating portion of the brush disc, and the first surface of the rotating portion rotates around a rotation axis relative to the second surface of the receiving portion, wherein at least one of the first surface and the second surface is formed by a thermoplastic crystalline polymer. The method of the present invention includes: a first injection molding step, injection molding one of the receiving portions of the brush disc and the brush head shell, using a first mold to correspondingly form the first surface of the brush disc or the second surface of the receiving portion of the brush head shell into a first surface shape; and a second injection molding step, placing one of the receiving portions forming the brush disc and the brush head shell into a second mold, injection molding to form the other of the receiving portions of the brush disc and the brush head shell, correspondingly molding the first surface of the brush disc and the second surface of the receiving portion of the brush head shell into a second surface shape, wherein the first surface shape and the second surface shape are formed to prevent the brush disc from escaping from the receiving portion along the rotation axis direction.

[0018] Preferably, after the injection molding step is completed, the brush disc is rotated relative to the accommodating portion of the brush head housing to separate the first surface and the second surface from each other.

[0019] Preferably, the brush head housing is integrally formed by injection molding in the first injection molding step; and the brush disc is integrally formed by injection molding using a thermoplastic crystalline polymer in the second injection molding step.

[0020] According to another aspect of the present invention, the accommodating portion also includes a peripheral wall and a bushing on the inner side of the peripheral wall, the bushing at least partially forms the second surface of the accommodating portion, and the bushing and the peripheral wall are maintained by injection molding so as not to detach along the direction of the rotation axis. Before the first injection molding step, the bushing is pre-injected and placed in the first mold.

[0021] According to another aspect of the present invention, in the pre-injection molding step, the bushing is injection molded using a thermoplastic crystalline polymer.

[0022] The present invention realizes a low-cost brush head and reduces wear between moving parts of the toothbrush head. The toothbrush head of the present invention omits the step of assembling the brush disc and the brush head housing during the manufacturing process, which not only improves production efficiency but also eliminates safety risks caused by assembly errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] For a more complete understanding of the present invention, reference may be made to the following description of exemplary embodiments considered in conjunction with the accompanying drawings, in which:

[0024] FIG1 shows a perspective view of a toothbrush head for an electric toothbrush according to a first embodiment of the present invention.

[0025] FIG2 shows a perspective cross-sectional view of a toothbrush head for an electric toothbrush according to a first embodiment of the present invention.

[0026] FIG3 shows another perspective sectional view of the toothbrush head for the electric toothbrush according to the first embodiment of the present invention, wherein the brush head housing is removed.

[0027] FIG4 shows a perspective view of a brush plate of a toothbrush head according to a first embodiment of the present invention.

[0028] FIG5 shows an exploded perspective view of the brush plate and the brush head housing of the toothbrush head according to the first embodiment of the present invention.

[0029] FIG6 shows a perspective view of the brush plate and the brush head housing of the toothbrush head according to the first embodiment of the present invention before being separated after injection molding.

[0030] FIG7 shows a cross-sectional view of a toothbrush head for an electric toothbrush according to a second embodiment of the present invention.

[0031] FIG8 shows a cross-sectional view of a toothbrush head for an electric toothbrush according to a third embodiment of the present invention.

[0032] Reference numerals:

[0033] 1, 1' brush head housing,

[0034] 11, 11' accommodation part

[0035] 15, 15" second surface

[0036] 151 End surface of the accommodation portion

[0037] 152 third cone portion

[0038] 153 Fourth cone surface

[0039] 2, 2' brush plate

[0040] 21 Carrier Department

[0041] 22 Rotating part

[0042] 25, 25" first surface

[0043] 251 annular end face

[0044] 252 first cone portion

[0045] 253 Second cone portion

[0046] 26 follower recess

[0047] 3. Stop sleeve.

[0048] 4 swing rod

[0049] 41 drive end

[0050] 5 bushings

[0051] 6. Cleaning Elements

[0052] L1 rotation axis

[0053] L2 swing axis

[0054] α angle

[0055] β angle

[0056] F1 external forces

[0057] F2 support force

[0058] F3 support force

[0059] F4 support DETAILED DESCRIPTION

[0060] The present invention is further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in a variety of other ways different from the description herein. Those skilled in the art can make similar generalizations and deductions based on actual application situations without violating the connotation of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.

[0061] Figures 1 to 6 illustrate a toothbrush head for an electric toothbrush according to a first embodiment of the present invention. The toothbrush head primarily comprises a brush head housing 1, a brush disc 2 housed in a receptacle 11 at one end of the housing 1, and a swing arm 4 disposed within the housing 1. As shown in Figure 2, the interior of the swing arm 4 is adapted to accommodate the drive shaft of an electric toothbrush. As the drive shaft reciprocates, the swing arm 4 swings back and forth within the housing 1 about its swing axis L2, thereby driving the brush disc 2 to reciprocate about its rotation axis L1 within a predetermined range of rotation angles.

[0062] As shown in Figures 2 and 3, the brush disc 2 primarily comprises a cleaning element carrier portion 21 and a rotating portion 22 disposed on one side of the carrier portion 21. In a preferred embodiment, the carrier portion 21 and the rotating portion 22 are integrally formed, with the rotating portion 22 protruding from one side of the carrier portion. The cleaning element carrier portion 21 of the brush disc 2 is generally located outside the accommodating portion 11, and cleaning elements 6, such as bristles, are mounted on the carrier portion 21. The rotating portion 22 is generally located within the accommodating portion 11, and a follower recess 26 is formed in the rotating portion 22. The driving end 41 of the swing arm 4 is inserted into the follower recess 26. As a result, the brush disc 2 can reciprocate about its rotation axis L1 as the swing arm 4 swings, thereby driving the cleaning elements 6 on the carrier portion 21 of the brush disc 2 to reciprocate, thereby achieving a teeth cleaning action. The follower recess 26 is preferably shaped as a recess with a rectangular cross-section.

[0063] Furthermore, as shown in FIG5 , a housing 11 is formed at one end of the brush head housing 1. The housing 11 includes a peripheral wall, both sides of which are open, thereby forming openings on both sides of the peripheral wall. At the other end of the brush head housing 1, a stopper sleeve 3 is inserted along the direction of the swing axis L2. The stopper sleeve 3 is configured to stop the swing rod 4 in the cavity of the brush head housing 1 to prevent the swing rod 4 from detaching from the brush head housing 1.

[0064] In a toothbrush head for an electric toothbrush, the brush disc 2 and the housing 11 of the brush head housing 1 are two components that can rotate relative to each other. As shown in FIG5 , the brush disc 2 has a first surface 25, and the housing 11 has a matching second surface 15. The first surface 25 rotates relative to the second surface 15 about a rotation axis L1. At the same time, the brush disc 2 and the housing 11 must be locked in position along the rotation axis L1 and cannot disengage. According to the present invention, one of the first surface 25 of the brush disc 2 and the second surface 15 of the housing 11 is formed from the other through corresponding molding and has a surface shape that locks movement along the rotation axis L1, thereby ensuring that the brush disc 2 rotates within the housing 11 but does not disengage along the rotation axis L1.

[0065] In the first embodiment, a brush head housing 1 having a receiving portion 11 is integrally formed in a mold by injection molding. After the injection molding is completed, the second surface 15 of the receiving portion 11 has a surface shape formed by the mold injection molding, that is, the second surface 15 is shaped by a portion of the mold during the injection molding process. After the brush head housing 1 cools, the brush head housing 1 is combined with the mold and the injection molding step is performed again to form the brush disc 2, wherein the rotating portion 22 of the brush disc 2 is formed by injecting a polymer material into the receiving portion 11. In this way, a portion of the surface of the brush disc 2 (the first surface 25) is molded corresponding to the surface shape of the second surface 15, that is, the first surface 25 is directly shaped by the second surface 15 during the injection molding step. It can be understood that the first surface 15 and the second surface 25 have surface shapes that are molded to match each other.

[0066] In particular, at least one of the brush disc 2 and the brush head shell 1 is made of a thermoplastic crystalline polymer. Preferably, the brush disc 2 is made of a thermoplastic crystalline polymer. For example, a polymer with a crystallinity of more than 65% can be selected, such as polyoxymethylene (POM), whose crystallinity is generally between 65% and 85%. Since the molecules of thermoplastic crystalline polymers are simple and the number of functional groups contained in the molecules is very small, the affinity between thermoplastic crystalline polymers and other polymer materials (including non-crystalline materials and similar crystalline materials) is very weak. There is no obvious bonding phenomenon between the second surface 15 of the accommodating portion 11 of the brush head shell formed in the two injection molding steps and the first surface 25 of the brush disc 2. Therefore, the brush disc 2 and the brush head shell 1 that are axially locked with each other and can rotate with each other can be achieved only through the injection molding step without the need for further installation steps.

[0067] On the other hand, because thermoplastic crystalline polymers typically have a high molding shrinkage (molding shrinkage refers to the percentage difference between the dimensions of a plastic part at molding temperature and its dimensions after being removed from the mold and cooled to room temperature), brush disc 2 formed of thermoplastic crystalline polymers will easily form a movement gap between the first surface 25 and the second surface 15 after cooling and shrinkage. The molding shrinkage of thermoplastic crystalline polymers suitable for the present invention is preferably greater than 0.05%, and more preferably greater than 0.5%. For example, the molding shrinkage of polyoxymethylene is approximately 1.7%. This high shrinkage causes polyoxymethylene to shrink significantly after cooling, thereby forming a gap between the first surface 25 of the brush disc 2 and the second surface 15 of the accommodating portion 11, which is more conducive to forming two relatively movable components in the toothbrush head.

[0068] In an alternative embodiment, the brush disc 2 can be first injection molded with a crystalline high molecular polymer such as polyformaldehyde. After the brush disc 2 is cooled and formed, the brush disc 2 is placed in the molding of the accommodating portion 11, and then the same crystalline polymer or other polymer (such as a semi-crystalline polymer or a non-crystalline polymer) is injected to envelop the rotating portion 22 of the brush disc 2 to form the accommodating portion 11, forming a relative surface that can move relative to each other.

[0069] In other alternative embodiments, a thermoplastic crystalline polymer may be used to form the brush head housing 1 , at least the receiving portion 11 of the brush head housing 1 , while the brush disc 2 is formed by injection molding using a non-crystalline polymer.

[0070] It should be understood that when at least one of the opposing surfaces 15, 25 is formed by injection molding of a crystalline high molecular polymer, due to the influence of the material or the injection molding temperature, after the injection molding is completed, adhesion may occur between the first surface 25 of the brush plate 2 and the second surface 15 of the accommodating portion 11. As shown in FIG6 , the two are adjacent to each other, but the adhered portion can be easily separated when a force is applied to rotate the brush plate 2 relative to the accommodating portion 11.

[0071] In the present invention, the surface shapes of the first surface 25 and the second surface 15 are specifically designed to prevent the brush disc 2 from escaping from the accommodating portion 11 of the brush head housing 1 along the direction of the rotation axis L1 (including the direction toward the cleaning elements and the direction away from the cleaning elements). To this end, preferably, the surface shapes of the first surface 25 and the second surface 15 are designed to include at least one section forming a conical surface that tapers toward the cleaning element carrier portion. Considering the shrinkage rate of crystalline polymer materials, the inclination angle of the conical surface relative to the rotation axis should be greater than 0.3 degrees. For manufacturing and reliability considerations, the inclination angle is preferably between 5 and 30 degrees.

[0072] As shown in Figure 5, the surface shapes of the first surface 15 and the second surface 25 in the first embodiment include two conical surfaces inclined in different directions. Specifically, in the direction of the rotation axis L1, the first surface 25 of the brush disc 2 includes: an annular end surface 251 of the carrier portion 21, which is transverse to the rotation axis; a first conical surface portion 252, which tapers away from the carrier portion 21 of the brush disc 2; and a second conical surface portion 253, which tapers toward the carrier portion 21 of the brush disc 2. The rotating portion 22 of the brush disc 2 has a smaller diameter in the middle and a larger diameter at both ends. Correspondingly, the second surface 15 of the brush head housing 1 includes: an end surface 151 of the accommodating portion 11, which abuts the annular end surface 251 of the carrier portion 21 when the brush disc 2 is mated with the brush head housing 1; a third conical portion 152, which tapers away from the carrier portion of the brush disc and faces the first conical portion 252; and a fourth conical portion 153, which tapers toward the carrier portion 21 of the brush disc 2 and faces the second conical portion 253. The second and fourth conical portions 253, 153 are further away from the cleaning element 6 than the first and third conical portions 152, 252. Thus, the peripheral wall of the accommodating portion 11 forms a cross-sectional shape that is thicker in the middle and thinner at both ends. Furthermore, arcuate transition portions may be provided between the first and second conical portions 252, 253, and between the third and fourth conical portions 152, 153, respectively, to reduce stress concentration. Preferably, the first tapered surface portion 252 and the second tapered surface portion 253 have substantially the same length in the direction of the rotation axis L1 .

[0073] The above-mentioned surface portions cooperate with each other to achieve the locking of the brush disc 2 and the brush head housing 1 along the direction of the rotation axis L1. On the one hand, the cooperation between the second conical surface portion 253 and the fourth conical surface portion 153 will generate a supporting force F4, which prevents the brush disc 2 from escaping from the housing 11 of the brush head housing 1 along the rotation axis L1 toward the cleaning element 6. On the other hand, when the brush disc 2 is subjected to an external force F1 (see Figure 1) in a direction away from the cleaning element 6, the cooperation between the first conical surface portion 252 and the third conical surface portion 152, as well as the annular end surface 251 of the carrier portion 22 and the side end surface 151 of the housing 11, prevents the brush disc 2 from leaving the direction away from the cleaning element 6 along the rotation axis L1. Therefore, the relative position of the brush disc 2 and the housing 11 in the direction of the rotation axis L1 is basically locked, ensuring the safety of the toothbrush head during operation. The brush disc 2 will not fall out of the housing, avoiding accidental detachment and causing harm to the human body.

[0074] The arrangement of the two conical surfaces in the first embodiment can help to reduce the wear of the mating end surfaces of the brush disc and the accommodating portion. Specifically, with reference to Figures 1, 2 and 5, when an external force F1 is applied to the cleaning element 6, the cooperation between the annular end surface of the carrier portion 22 and the end surface of the accommodating portion 11 provides a supporting force F2 along the rotation axis L1. At the same time, the second surface 15 of the first conical portion 252 and the third conical portion 152 facing each other generate a supporting force F3. When F1 remains unchanged, the component of the supporting force F3 on the rotation axis L1 reduces the force F2 on the end surfaces 151 and 251, thereby reducing the friction generated between the two end surfaces 151 and 251, reducing the wear between the end surfaces 151 and 251, and extending the service life of the toothbrush head.

[0075] In a cross section in the radial direction passing through the rotation axis L1, each conical surface portion can be a straight line or an arc. Preferably, as shown in FIG2 , the angle α of the conical surface that tapers toward the side of the cleaning element 6 (i.e., the first conical surface portion 252 and the third conical surface portion 152) relative to the rotation axis L1 is preferably greater than 3 degrees and less than or equal to 90 degrees. The angle β of the conical surface that tapers away from the cleaning element 6 (i.e., the second conical surface portion 253 and the fourth conical surface portion 153) is greater than 0.3 degrees, and preferably, the angle β is within the range of 5-30 degrees.

[0076] FIG7 shows a toothbrush head for an electric toothbrush according to a second embodiment of the present invention. Unlike the first embodiment, a bushing 5 is additionally provided within the peripheral wall of the receiving portion 11' of the brush head housing 1' of the second embodiment. The inner surface of the bushing 5 rotatably abuts the outer surface of the rotating portion 22 of the brush disc 2'. Therefore, the surface of the bushing 5 constitutes a portion of the mating surface of the brush head housing 1' for rotation relative to the brush disc 2'. In other words, the surface of the bushing 5 corresponds to the second surface 15 of the receiving portion 11 in the first embodiment.

[0077] When producing the toothbrush head of the second embodiment, preferably in the pre-injection molding step, the bushing 5 is formed from a thermoplastic crystalline polymer such as polyoxymethylene. Subsequently, the bushing 5 is placed in a mold for manufacturing the brush disc 2', and the brush disc 2' is formed by injection molding. At this time, the brush disc 2' will have a surface shape molded corresponding to a portion of the surface of the bushing 5. The material of the brush disc can be a thermoplastic plastic such as PP, POM, ABS, etc. with a shrinkage rate greater than 0.05%, preferably greater than 0.5%, and more preferably greater than 1.0%. Due to the characteristics of thermoplastic crystalline polymers, the rotating part 22' of the brush disc 2' will be separated from the bushing 5 to form a dynamic fit. Finally, the brush head shell 1 is formed around the bushing 5 by injection molding. The material of the brush head shell 1 can be a crystalline polymer material or a non-crystalline polymer material.

[0078] In the second embodiment, bushing 5 has a substantially uniform thickness. The inner and outer surfaces of bushing 5 have similar shapes to the first surface 25 and second surface 15 of the first embodiment, namely, they both comprise two conical surfaces tapering in different directions. Furthermore, bushing 5 is provided with a through-hole through which the driving end 41' of rocker arm 4 passes.

[0079] In the second embodiment, although the bushing 5 is provided as a part of the accommodating portion 11', it should be understood that the bushing 5 and the peripheral wall of the accommodating portion 11' can be in a relatively movable state. In this case, the bushing 5 plays a role similar to a bearing, so that the brush disc 2' rotates more smoothly in the accommodating portion 11'.

[0080] FIG8 shows a cross-sectional view of a toothbrush head according to a third embodiment of the present invention. The third embodiment differs from the first embodiment in the surface shapes of the mutually mating surfaces of the receiving portion 11″ and the rotating portion 22″. As shown in FIG8 , the first surface 15″ and the second surface 25″ that rotate to fit together only include tapered conical surfaces toward the side where the cleaning elements are located. The third embodiment is particularly suitable for situations where the length of the receiving portion 11″ along the axis of rotation is relatively long. Since the contact area of ​​the mutually mating surfaces is relatively large, the pressure of the mating contact surfaces is reduced, and wear will be improved.

[0081] In one embodiment, the length h of the accommodating portion 11" along the rotation axis L1 is set to be approximately equal to 12 mm, the diameter w of a portion of the carrier portion of the rotating portion 22" is 6 mm, and the brush disc is formed by polyformaldehyde injection molding. The shrinkage rate of polyformaldehyde is 1.7%, and the gap generated by the shrinkage of the conical surface of the rotating portion 22" is 6*0.017 / 2=0.051 mm. β is set to 0.3 degrees, and the radial offset of the surface of the accommodating portion 11" is 12 mm*sin(0.3)=0.062 mm. Therefore, setting β to be greater than 0.3 degrees can ensure that the accommodating portion 11" prevents the brush disc from detaching to avoid causing human injury.

[0082] In other alternative embodiments, the first surface 25 and the second surface 15 of the accommodating portion 11 of the brush disc 2 and the brush head housing 1 are not limited to the above embodiments. For example, the surface shapes of flanges and grooves, or the matching step surface shapes can also be formed. These shapes can also prevent the brush disc from disengaging along the direction of the rotation axis L1. For this purpose, at least a portion of the surface that will come into contact when the brush disc and the accommodating portion rotate relative to each other is constructed to provide a shape that can provide a force that prevents the brush disc from disengaging from the accommodating portion along the direction of the rotation axis L1.

[0083] In other alternative embodiments, the layout and shape of the cleaning elements are not limited to the embodiments shown in the accompanying drawings, and there may be various variations, such as a cross-layout of the cleaning elements. This layout usually requires an independent cleaning element carrier portion to facilitate the realization of a special layout of the cleaning elements. For this purpose, unlike the aforementioned embodiment in which the carrier portion and the rotating portion are integrally formed, the cleaning elements can be installed on an independent carrier portion. After a toothbrush head with a non-removable brush disc is made by the method of the present invention, the brush disc may only include the rotating portion, and then the carrier portion with the cleaning elements installed is fastened to the brush disc by methods such as ultrasonic welding and threaded fasteners. For such a toothbrush head with an independent carrier portion, the present invention is still applicable.

[0084] The first surface of the brush disc and the second surface of the accommodating portion are molded corresponding surfaces, that is, one of the first surface of the brush disc and the second surface of the accommodating portion is injection-molded using the other as a model in the injection molding step without additional machining, and after the injection molding is completed, the brush disc and the accommodating portion are integrated together, and the position locking in the direction of the rotation axis is achieved by means of the conical or stepped surface shape of the molded corresponding surface, omitting the existing connecting shaft structure.

[0085] On the other hand, the toothbrush head of the present invention omits the step of assembling the brush disc and the brush head shell during the manufacturing process, which not only improves the production efficiency but also eliminates the safety risks that may be caused by assembly errors.

[0086] Although the present invention is disclosed above with reference to preferred embodiments, this is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modifications, equivalent variations, and modifications made to the above embodiments in accordance with the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection defined by the claims of the present invention.

Claims

1. A toothbrush head for an electric toothbrush, comprising: A brush plate, the brush plate comprising a rotating portion; as well as A brush head housing, one end of which forms a receiving portion, the receiving portion receiving the rotating portion of the brush plate, the first surface of the brush plate rotating around a rotation axis relative to the second surface of the receiving portion, It is characterized in that One of the first surface of the brush plate and the second surface of the receiving portion has a first surface shape formed by mold injection, The other of the first surface of the brush plate and the second surface of the receiving portion has a second surface shape molded to correspond to the first surface shape; At least one of the first surface and the second surface is formed of a thermoplastic crystalline polymer, and the first surface shape and the second surface shape are formed to prevent the brush plate from being separated from the receiving portion of the brush head housing in the rotation axis direction.

2. The toothbrush head according to claim 1, characterized in that The brush plate is integrally formed of the thermoplastic crystalline polymer, The molding shrinkage of the thermoplastic crystalline polymer is greater than 0.5%.

3. The toothbrush head according to claim 1, characterized in that The brush plate further comprises a cleaning element carrier portion, and the rotating portion is arranged on one side of the carrier portion; The first surface and the second surface include at least one section of a surface that forms a cone that tapers toward the cleaning element carrier portion, and the conical surface has an inclination angle greater than 0.3 degrees relative to the rotation axis.

4. The toothbrush head according to any one of claims 1 to 3, characterized in that In the direction of the rotation axis, the first surface of the brush disc comprises: a first tapered portion that tapers in a direction away from a side of the brush plate to which cleaning elements are attached; and A second conical surface portion, the second conical surface portion is on a side toward which the cleaning element is attached to the brush plate tapers upward; and The second surface of the brush head housing comprises: a third conical surface portion, the third conical surface portion being gradually tapered in a direction away from a side of the brush plate to which the cleaning elements are attached and matching the first conical surface portion; A fourth conical surface portion is gradually reduced in a direction toward a side of the brush plate to which the cleaning elements are attached and matches the second conical surface portion.

5. The toothbrush head according to claim 4, characterized in that The brush plate integrally comprises a cleaning element carrier portion, and the rotating portion protrudes from one side of the carrier portion; The first surface of the brush plate further includes: an annular end surface of the carrier portion, the annular end surface being transverse to the rotation axis; The second surface of the brush head housing further includes: an end surface of the accommodating portion.

6. The toothbrush head according to claim 4, characterized in that The toothbrush head also includes a swing rod that reciprocates in the brush head housing. The rotating portion is formed with a follower recess for receiving the driving end of the swing rod, wherein the follower recess is at least partially arranged on the second conical surface portion of the rotating portion.

7. The toothbrush head according to claim 1, characterized in that The accommodation portion further includes a peripheral wall and a bushing inside the peripheral wall, the bushing forming the second surface of the accommodation portion, and the bushing and the peripheral wall are retained by injection molding so as not to be separated in the direction of the rotation axis.

8. The toothbrush head according to claim 7, characterized in that The bushing is formed from the thermoplastic crystalline polymer.

9. The toothbrush head according to claim 1, characterized in that: The accommodating portion has a peripheral wall surrounding the rotation axis, both sides of the peripheral wall have openings, and the rotating portion of the brush plate extends from the opening on one side of the peripheral wall to the opening on the other side of the peripheral wall.

10. The toothbrush head according to claim 1, characterized in that The thermoplastic crystalline polymer is polyoxymethylene.

11. A method for manufacturing a toothbrush head, wherein the toothbrush head comprises: A brush plate, the brush plate comprising a rotating portion; and a brush head housing, one end of the brush head housing forming a receiving portion, the receiving portion receiving the rotating portion of the brush plate, and a first surface of the rotating portion rotating around a rotation axis relative to a second surface of the receiving portion, wherein at least one of the first surface and the second surface is formed of a thermoplastic crystalline polymer, The method comprises: A first injection molding step, forming one of the brush plate and the accommodating portion of the brush head housing by injection molding, and using a first mold to correspondingly form a first surface of the brush plate or a second surface of the accommodating portion of the brush head housing into a first surface shape; and In the second injection molding step, one of the accommodating parts forming the brush plate and the brush head housing is placed into a second mold, and the other one of the accommodating parts of the brush plate and the brush head housing is formed by injection molding, and the other one of the first surface of the brush plate and the second surface of the accommodating part of the brush head housing is molded into a second surface shape corresponding to the first surface shape, wherein the first surface shape and the second surface shape are formed to prevent the brush plate from escaping from the accommodating part along the direction of the rotation axis.

12. The method according to claim 11, characterized in that After the injection molding step is completed, the brush plate is rotated relative to the receiving portion of the brush head housing to separate the first surface and the second surface from each other.

13. The method according to claim 11, characterized in that In the first injection molding step, the brush head housing is integrally formed by injection molding; In the second injection molding step, the brush plate is integrally formed by injection molding using a thermoplastic crystalline polymer.

14. The method according to claim 11, characterized in that The receiving portion further includes a peripheral wall and a bushing inside the peripheral wall, the bushing forming the second surface of the receiving portion, and the bushing and the peripheral wall are retained by injection molding so as not to be separated along the rotation axis direction. In the method, Before the first injection molding step, the bushing is pre-injected and placed in The first mold.

15. The method according to claim 14, characterized in that: In the pre-injection molding step, the bushing is injection molded using the thermoplastic crystalline polymer.

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