Machine body assembly of handheld appliance and electric toothbrush

Abstract

The embodiment of the utility model discloses a machine body assembly of a handheld appliance and an electric toothbrush, and the machine body assembly of the handheld appliance comprises a machine body shell which comprises a cylindrical outer wall and a lining formed on the inner wall surface of the outer wall; an outer via hole penetrating through the outer wall and the lining is formed in the front end of the machine body shell; the outer sealing piece is arranged in the outer via hole and is in sealing fit with the outer via hole, and the outer sealing piece is provided with an outer shaft hole communicated with the containing cavity of the machine body shell; the fixed seat is arranged in the accommodating cavity of the machine body shell and is fixedly arranged relative to the machine body shell; the driving shaft penetrates through the outer shaft hole; the outer via hole comprises a first via hole formed in the outer wall and a second via hole formed in the lining, and an annular radial sealing face is formed in the position, on the periphery of the first via hole, of the inner wall face of the outer wall. The outer sealing piece is clamped between the fixing base and the machine body shell, and the outer sealing piece is in sealing fit with the radial sealing face. The outer sealing piece is directly in sealing fit with the radial sealing surface of the inner wall surface of the outer wall, so that a better sealing effect is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of waterproofing for handheld appliances, and particularly to a body assembly of a handheld appliance and an electric toothbrush. Background Art

[0002] A handheld appliance can drive a working component, such as a toothbrush head, through a rotating shaft extending out of the body. If the working environment of such handheld appliances has a high degree of water vapor exposure, it is necessary to perform a good waterproof seal around the rotating shaft. Generally, such a waterproof seal includes two interfaces. One interface is the fit between the seal and the rotating shaft, and the other interface is the fit between the seal and the body housing. Of course, these two sealing interfaces are relatively independent because the failure of any one of the sealing interfaces will cause water vapor to invade the body, thereby causing the handheld appliance to malfunction. Therefore, the structural form of the body housing can affect the sealing interface between it and the seal. Referring to the Chinese utility model patent with the authorization announcement number CN220193230U applied by the applicant earlier, at the radially extending part of the sealing interface between the brush handle housing and the seal, the injection-molded insulating inner shell cooperates with the seal. However, due to manufacturing process limitations, the outer surface of the insulating inner shell is rough, has fiber patterns, and has low flatness or even has depressions and cracks, resulting in a high risk of failure of the sealing interface between the insulating inner shell and the seal, thereby reducing the yield rate or service life of the handheld appliance. Summary of the Utility Model

[0003] The main purpose of the present application is to propose a body assembly of a handheld appliance and an electric toothbrush, aiming to solve the technical problem that there is a high risk of failure of the sealing interface between the body housing of the existing handheld appliance body assembly and electric toothbrush and the seal.

[0004] To achieve the above object, the body assembly of the handheld appliance proposed in the present application includes:

[0005] A body housing, including a cylindrical outer wall and a lining formed on the inner wall surface of the outer wall; the front end of the body housing is provided with an outer through hole penetrating the outer wall and the lining;

[0006] An outer seal, disposed in the outer through hole and in sealing cooperation with the outer through hole, the outer seal being provided with an outer shaft hole communicating with the cavity of the body housing;

[0007] A fixed seat, disposed in the cavity of the body housing and fixedly arranged relative to the body housing; and

[0008] A drive shaft, passing through the outer shaft hole and extending out of the body housing, the drive shaft being in sealing and rotatable cooperation with the outer shaft hole; wherein,

[0009] The outer through-hole includes a first through-hole provided on the outer wall and a second through-hole provided on the inner liner. An annular radial sealing surface is formed on the inner wall surface of the outer wall around the first through-hole;

[0010] The outer seal is clamped between the fixed seat and the fuselage shell, and the outer seal is in sealing cooperation with the radial sealing surface.

[0011] Preferably, the outer seal includes an inner ring wall, a longitudinal ring wall and an outer ring wall, wherein,

[0012] Both the inner ring wall and the outer ring wall extend radially. The inner ring wall protrudes forward from the outer ring wall, and the outer shaft hole is formed on the inner wall surface of the inner ring wall;

[0013] The longitudinal ring wall connects the outer edge of the inner ring wall and the inner edge of the outer ring wall; the outer peripheral surface of the longitudinal ring wall is in sealing cooperation with the first through-hole.

[0014] Preferably, the outer seal further includes an inner cylinder extending backward from the inner edge of the inner ring wall, and the outer shaft hole is also formed on the inner wall surface of the inner cylinder;

[0015] The fixed seat is provided with an inner through-hole for the driving shaft to pass through. A circular support wall is provided on the front wall surface of the fixed seat around the inner through-hole. The support wall extends into the radial inner side of the longitudinal ring wall, and the support wall abuts against the inner peripheral surface of the longitudinal ring wall.

[0016] Preferably, a clearance is formed between the inner wall surface of the inner through-hole and the outer peripheral surface of the inner cylinder.

[0017] Preferably, the inner wall surface of the inner through-hole is provided with an annular sealing groove, and the sealing groove has an axially opposite front wall surface and a rear wall surface;

[0018] The fuselage assembly of the handheld appliance further includes an inner seal. The inner seal is arranged in the inner through-hole and extends into the sealing groove. The inner seal is in sealing and rotatable cooperation with the front wall surface and the rear wall surface respectively; the inner seal is provided with an inner shaft hole that is in sealing and fixed socket connection with the driving shaft.

[0019] Preferably, a sealing chamber is formed by enclosing the inner wall surface of the inner seal and the sealing groove. The fuselage assembly of the handheld appliance further includes lubricating oil filled in the sealing chamber. The lubricating oil forms an oil seal interface between the inner seal and the front wall surface, and between the inner seal and the rear wall surface.

[0020] Preferably, the fixed seat includes a base and a bracket fixedly connected to the base. The base and the bracket enclose to form the inner through hole and the sealing groove. The inner through hole includes a rear opening formed in the base and a front opening formed in the bracket. The front wall surface and the support wall of the sealing groove are formed in the bracket, and the rear wall surface of the sealing groove is formed in the base.

[0021] Preferably, the outer seal further includes an outer cylinder extending backward from the inner edge of the inner ring wall. The inner liner further includes a limiting cylinder disposed around the second through hole. The outer peripheral surface of the outer seal is in sealing cooperation with the inner wall surface of the limiting cylinder, and the inner peripheral surface of the outer seal is in limiting abutment with the outer peripheral surface of the bracket.

[0022] Preferably, a plurality of material-reducing holes are provided on the outer peripheral surface of the bracket. The plurality of material-reducing holes are arranged at intervals in the circumferential direction, and the material-reducing holes are axially offset from the front end surface of the bracket.

[0023] Preferably, among the rear end surface of the bracket and the front end surface of the base, one of them is provided with a positioning groove, and the other is provided with a positioning protrusion adapted to the positioning groove. The base and the bracket are fixed by an ultrasonic welding process.

[0024] Preferably, the outer wall is made of a metal material, the inner liner is made of a plastic material, an annular limiting groove is provided on the radial sealing surface, and a limiting convex ring adapted to the limiting groove is provided on the front end surface of the outer seal.

[0025] The present application also provides an electric toothbrush, including a motor and the body assembly of the handheld device as described above. The motor is disposed in the cavity of the body housing, and the drive shaft is connected to the rotor of the motor.

[0026] By directly sealing the outer seal with the radial sealing surface of the inner wall surface of the outer wall, the body assembly of the handheld device of the present utility model can obtain a better surface quality of the radial sealing surface compared with the outer surface of the inner liner because the radial sealing surface can be locally processed by machining or other methods, while the inner liner is usually formed on the inner wall surface of the outer wall by a secondary injection molding process or a coating process and has many protrusions blocking it, resulting in a relatively rough outer surface. Therefore, the sealing effect of the outer seal is improved, and further the failure risk of the sealing interface between the body housing and the outer seal is reduced, and the product yield and service life are improved. Description of the Drawings

[0027] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those skilled in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0028] Figure 1 Schematic diagram of the three-dimensional structure of the electric toothbrush of the present utility model;

[0029] Figure 2 is Figure 1 Schematic diagram of the partial structure at the front end of the electric toothbrush in;

[0030] Figure 3 is Figure 2 Schematic diagram of the three-dimensional structure of the partial structure in;

[0031] Figure 4 is Figure 3 Schematic diagram of the three-dimensional structure of the bracket in;

[0032] Figure 5 is Figure 2 Schematic diagram of the three-dimensional structure of the partial structure in another angle;

[0033] Figure 6 is Figure 2 Schematic diagram of the exploded structure of the partial structure in another angle;

[0034] Figure 7 is the schematic diagram of the three-dimensional structure of the body housing in 6;

[0035] Figure 8 is the schematic diagram of the three-dimensional structure of the outer wall of the body housing in 6;

[0036] Figure 9 is the front view structure diagram of the partial structure in 2;

[0037] Figure 10 is Figure 9 Schematic diagram of the sectional structure along the X-X line in;

[0038] Figure 11 is Figure 9 Combined structure diagram of the sectional structure and the exploded structure along the X-X line in;

[0039] Figure 12 is Figure 11 Schematic diagram of the partial structure at A in.

[0040] Explanation of the reference numerals in the drawings:

[0041] Label Name Label Name Label Name 100 Electric toothbrush 22 Inner ring wall 37 Bracket 200 Body assembly 23 Longitudinal ring wall 38 Support wall 10 Body housing 24 Outer ring wall 39 Front wall surface 11 Outer wall 25 Inner cylinder 40 Front opening 12 First through hole 26 Outer cylinder 41 Material reduction hole 13 Radial sealing surface 27 Limit convex ring 42 Positioning groove 14 Limit groove 30 Fixed seat 50 Drive shaft 15 Liner 31 Inner through hole 60 Avoidance gap 16 Second through hole 32 Sealing groove 70 Inner seal 17 Limit cylinder 33 Base 71 Inner shaft hole 18 Outer through hole 34 Rear wall surface 80 Sealing chamber 20 Outer seal 35 Rear opening 21 Outer shaft hole 36 Positioning protrusion Detailed implementation manners

[0042] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0043] Referring to Figures 1-3 , Figure 9 and Figure 10 , in an embodiment, the body assembly 200 of the handheld device proposed in the present application includes:

[0044] The body housing 10 includes a cylindrical outer wall 11 and a lining 15 formed on the inner wall surface of the outer wall 11; a through outer hole 18 is provided at the front end of the body housing 10 and penetrates through the outer wall 11 and the lining 15.

[0045] The outer seal 20 is disposed in the outer hole 18 and is in sealing cooperation with the outer hole 18. The outer seal 20 is provided with an outer shaft hole 21 communicating with the cavity of the body housing 10.

[0046] The fixed seat 30 is disposed in the cavity of the body housing 10 and is fixedly arranged relative to the body housing 10; and

[0047] The drive shaft 50 passes through the outer shaft hole 21 and extends out of the body housing 10. The drive shaft 50 is in sealing and rotatable cooperation with the outer shaft hole 21; wherein,

[0048] The outer hole 18 includes a first through hole 12 provided on the outer wall 11 and a second through hole 16 provided on the lining 15. A circular radial sealing surface 13 is formed on the inner wall surface of the outer wall 11 around the first through hole 12.

[0049] The outer seal 20 is clamped between the fixed seat 30 and the body housing 10, and the outer seal 20 is in sealing cooperation with the radial sealing surface 13.

[0050] In this embodiment, some parts of the body housing 10 can be held, and the body housing 10 can provide support and protection for the components installed inside the body housing 10. Generally, the material strength of the outer wall 11 is higher than that of the lining 15, but at the same time it is suitable for forming a simple structure. For example, the outer wall 11 is made of aluminum alloy or stainless steel and is formed into a long cylindrical structure by multiple deep drawing processes. The lining 15 is usually made of a thermoplastic material, such as a plastic suitable for injection molding. In this way, the lining 15 can be formed into a relatively complex shape on the inner side of the outer wall 11 by secondary injection molding, so as to provide a better installation and fixing structure for the components inside the body housing 10.

[0051] The outer seal 20 is usually made of a flexible material, such as silicone, rubber, etc. As Figure 10 and Figure 11 shown, in order to improve the sealing effect by increasing the contact area, the cross-sectional shape of the inner wall surface of the outer shaft hole 21 is wavy, that is, it has multiple folds. In this way, when the outer seal is radially compressed, the inner wall surface of the outer shaft hole 21 can expand to increase the contact area; the parts that cannot expand can form small cavities for sealing with the outer peripheral surface of the drive shaft 50.

[0052] The fixed seat 30 can be directly fixedly connected to the body shell 10, or can be fixed by means of being clamped by other components with the body shell 10. Since the fixed seat 30 needs other supporting and limiting functions, the fixed seat 30 is usually made of a hard material, such as hard rubber. In addition, the fixed seat 30 can be a single-piece component or can be assembled from multiple components. It can be understood that under the clamping action of the body shell 10 and the fixed seat 30, the outer seal 20 and the radial sealing surface 13 can form an interference fit required for sealing.

[0053] The drive shaft 50 is used to play a role in connection and transmission. For example, when applied to the electric toothbrush 100, the front end of the drive shaft 50 is used to install the brush head, and the rear end is fixedly connected to the rotor of the motor or becomes a part of the electronic rotor.

[0054] The body assembly 200 of the handheld appliance of the present utility model seals and mates the outer seal 20 directly with the radial sealing surface 13 of the inner wall surface of the outer wall 11. Since the radial sealing surface 13 can be locally processed by means such as machining, while the inner liner 15 is usually formed on the inner wall surface of the outer wall by a secondary injection molding process or a coating process and has many protrusions blocking, the resulting outer surface is relatively rough. Therefore, the radial sealing surface 13 is easier to obtain a better surface quality compared to the outer surface of the inner liner 15. Thus, the sealing effect of the outer seal 20 is improved, and further the failure risk of the sealing interface between the body shell 10 and the outer seal 20 is reduced, and the product yield and service life are improved.

[0055] Furthermore, the outer seal 20 includes an inner ring wall 22, a longitudinal ring wall 23 and an outer ring wall 24, wherein,

[0056] Both the inner ring wall 22 and the outer ring wall 24 extend radially, the inner ring wall 22 protrudes forward from the outer ring wall 24, and the outer shaft hole 21 is formed on the inner wall surface of the inner ring wall 22;

[0057] The longitudinal ring wall 23 connects the outer edge of the inner ring wall 22 and the inner edge of the outer ring wall 24; the outer peripheral surface of the longitudinal ring wall 23 is sealed and mated with the first through hole 12.

[0058] In this embodiment, the shoulder formed by the inner ring wall 22 and the longitudinal ring wall 23 can fill the annular space between the transmission shaft and the inner wall surface of the first through hole 12, so that water vapor is not likely to accumulate in this annular space. In addition, through the sealing fit between the longitudinal ring wall 23 and the first through hole 12, not only the sealing area is increased, but also the formation of a water squeezing or water storage space between the longitudinal ring wall 23 and the inner wall surface of the first through hole 12 can be prevented, thus further improving the sealing effect.

[0059] Furthermore, the outer seal 20 further includes an inner cylinder 25 formed by extending backward from the inner edge of the inner ring wall 22, and an outer shaft hole 21 is also formed on the inner wall surface of the inner cylinder 25;

[0060] The fixing seat 30 is provided with an inner through hole 31 for the driving shaft 50 to pass through. The front wall surface 39 of the fixing seat 30 is provided with an annular support wall 38 around the inner through hole 31. The support wall 38 extends into the radial inner side of the longitudinal ring wall 23, and the support wall 38 abuts against the inner peripheral surface of the longitudinal ring wall 23.

[0061] In this embodiment, by providing the inner cylinder 25, the sealing fit area between the outer seal 20 and the driving shaft 50 can be increased, thereby improving the sealing effect. In addition, the integral setting of the inner cylinder 25 and the inner ring wall 22 also reduces the water leakage link. Further, since the support wall 38 can limit the longitudinal ring wall 23 in the radial direction, the radial inward offset of any part of the longitudinal ring wall 23 can be prevented. In this way, not only the formation of a water squeezing or water storage space between the longitudinal ring wall 23 and the inner wall surface of the first through hole 12 is avoided, but also the outer side surface of the inner ring wall 22 is prevented from being concave, thereby preventing poor appearance.

[0062] Furthermore, a clearance gap 60 is formed between the inner wall surface of the inner through hole 31 and the outer peripheral surface of the inner cylinder 25. Thus, when the driving shaft 50 has a radial offset, such as radial vibration, the inner cylinder 25 can move together with the driving shaft 50, so that the inner wall surface of the inner through hole 31 and the driving shaft 50 are prevented from eccentrically squeezing the inner cylinder 25 together. In this way, the uniformity of the sealing pressure between the content and the driving shaft 50 is ensured, thereby improving the sealing effect.

[0063] Furthermore, please refer to Figure 11 and Figure 12 , in an embodiment, the inner wall surface of the inner through hole 31 is provided with an annular sealing groove 32, and the sealing groove 32 has an axially opposite front wall surface 39 and a rear wall surface 34;

[0064] The body assembly 200 of the handheld appliance further includes an inner seal 70. The inner seal 70 is disposed in the inner through hole 31 and extends into the sealing groove 32. The inner seal 70 is respectively in sealing and rotatable fit with the front wall surface 39 and the rear wall surface 34; the inner seal 70 is provided with an inner shaft hole 71 that is in sealing and fixed sleeve connection with the driving shaft 50.

[0065] In this embodiment, the provision of the inner seal 70 can add a dynamic seal interface, thereby enhancing the sealing effect during the rotation of the drive shaft 50. Therefore, in order to reduce friction and facilitate fixation, preferably, the fixing seat 30 is made of PC material, that is, polycarbonate material, and both the front wall surface 39 and the rear wall surface 34 of the seal groove 32 are smooth surfaces, that is, the so-called high-gloss surfaces.

[0066] Further, the inner seal 70 and the inner wall surface of the seal groove 32 enclose a seal chamber 80. The body assembly 200 of the handheld appliance further includes lubricating oil filled in the seal chamber 80, and the lubricating oil forms oil seal interfaces between the inner seal 70 and the front wall surface 39, and between the inner seal 70 and the rear wall surface 34.

[0067] In this embodiment, filling the seal chamber 80 with lubricating oil can not only further reduce friction and thus reduce wear, but also enhance the sealing effect by forming an additional oil seal interface.

[0068] Further, the fixing seat 30 includes a base 33 and a bracket 37 fixedly connected to the base 33. The base 33 and the bracket 37 enclose an inner through hole 31 and a seal groove 32. The inner through hole 31 includes a rear opening 35 formed in the base 33 and a front opening 40 formed in the bracket 37. The front wall surface 39 and the support wall 38 of the seal groove 32 are formed in the bracket 37, and the rear wall surface 34 of the seal groove 32 is formed in the base 33.

[0069] In this embodiment, since the overall size of the fixing seat 30 is small and the shape of the seal groove 32 is not suitable for direct demolding, that is, it cannot be demolded in a single direction, the fixing seat 30 is formed by connecting the separate base 33 and the bracket 37. In this way, the process cost of forming the inner cavity of the fixing seat 30 can be reduced. For example, the base 33 and the bracket 37 are respectively formed by metal die casting and then connected by threading or welding; or both the base 33 and the bracket 37 are made of plastic material, and the two are fixed by ultrasonic welding or dispensing.

[0070] Further, the outer seal 20 further includes an outer cylinder 26 extending backward from the inner edge of the inner ring wall 22. The inner liner 15 further includes a limiting cylinder 17 provided around the second through hole 16. The outer peripheral surface of the outer seal 20 is in sealing cooperation with the inner wall surface of the limiting cylinder 17, and the inner peripheral surface of the outer seal 20 is in limiting contact with the outer peripheral surface of the bracket 37.

[0071] In this embodiment, the sealing cooperation between the outer peripheral surface of the outer seal 20 and the inner wall surface of the limiting cylinder 17 can, on the one hand, extend the sealing interface between the outer seal 20 and the body housing 10, thereby enhancing the sealing effect; on the other hand, by forming a greater degree of wrapping of the outer seal 20, a better limiting effect is achieved.

[0072] Further, referring to Figures 3-6 ,Figures 10 to 12 In one embodiment, a plurality of material-reducing holes 41 are provided on the outer peripheral surface of the bracket 37. The plurality of material-reducing holes 41 are arranged at intervals in the circumferential direction, and the material-reducing holes 41 are axially offset from the front end surface of the bracket 37.

[0073] In this embodiment, due to the different shrinkage rates of different materials, in order to stably support the outer seal 20, the dimension between the front end surface and the rear end surface of the bracket 37 is relatively large. By providing a plurality of material-reducing holes 41 on the outer peripheral surface of the bracket 37, the material application range of the bracket 37 can be expanded. That is, while ensuring a relatively large thickness in the front and rear directions of the bracket 37, the surface quality of the front end surface of the bracket 37 can be ensured, thereby ensuring the pressing effect of the bracket 37 on the outer ring wall 24 and the radial support effect on the outer cylinder 26 directly.

[0074] Further, referring to Figure 3 、 Figure 4 and Figure 6 In one embodiment, among the rear end surface of the bracket 37 and the front end surface of the base 33, one of them is provided with a positioning groove 42, and the other is provided with a positioning protrusion 36 adapted to the positioning groove 42. The base 33 and the bracket 37 are fixed by an ultrasonic welding process.

[0075] In this embodiment, ultrasonic welding can form a better fixing and sealing effect, thereby ensuring the stable connection between the base 33 and the bracket 37 and the sealing effect of the sealing chamber 80.

[0076] Further, referring to Figure 3 、 Figures 6-8 、 Figure 10 and Figure 11 In one embodiment, the outer wall 11 is made of a metal material, the inner liner 15 is made of a plastic material, an annular limiting groove 14 is provided on the radial sealing surface 13, and a limiting convex ring 27 adapted to the limiting groove 14 is provided on the front end surface of the outer seal 20.

[0077] In this embodiment, the cooperation between the limiting convex ring 27 and the limiting groove 14 can better prevent the radial misalignment of the corresponding part of the outer seal 20 on the radial sealing surface 13, and can also increase the sealing area. Therefore, the sealing effect of the product is further improved.

[0078] Referring to Figure 1 This application also provides an electric toothbrush 100, which includes a motor (not shown in the figure) and the body assembly 200 of the handheld device as described above. The motor is arranged in the cavity of the body housing 10, and the drive shaft 50 is connected to the rotor of the motor. The specific structure of the body assembly 200 of the handheld device refers to the above embodiment. Since this electric toothbrush 100 adopts all the technical solutions of the above all embodiments, it also has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated here one by one.

[0079] In this embodiment, the type of the motor is not specifically limited. In order to achieve more complex driving, the motor preferably adopts a direct current brushless motor. In order to facilitate the fixation of the motor, an end plate with a larger thickness can be provided and fixedly connected to the outer shell of the motor with a smaller thickness, for example, by welding; and then screws are used to connect the end plate and the fixing seat 30.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present application.

Claims

1. A body assembly of a handheld device, characterized in that: include: The fuselage shell comprises a cylindrical outer wall and an inner lining formed on the inner wall surface of the outer wall; the front end of the fuselage shell is provided with an outer through hole penetrating the outer wall and the inner lining; An external sealing member, disposed in the external through hole and sealingly matched with the external through hole, the external sealing member being provided with an external shaft hole communicating with the cavity of the fuselage shell; A fixing seat, disposed in the cavity of the fuselage shell and fixedly arranged relative to the fuselage shell; and A drive shaft is inserted into the outer shaft hole and extends outward from the body shell, and the drive shaft is sealed and rotatably matched with the outer shaft hole; wherein, The outer via hole comprises a first via hole provided on the outer wall and a second via hole provided on the inner liner, and an inner wall surface of the outer wall forms an annular radial sealing surface at the periphery of the first via hole; The outer seal is clamped between the fixing seat and the fuselage shell, and the outer seal is sealingly matched with the radial sealing surface.

2. The body assembly of the handheld device according to claim 1, characterized in that: The outer seal comprises an inner ring wall, a longitudinal ring wall and an outer ring wall, wherein: The inner annular wall and the outer annular wall both extend radially, the inner annular wall protrudes forward from the outer annular wall, and the outer shaft hole is formed on the inner wall surface of the inner annular wall; The longitudinal annular wall connects the outer edge of the inner annular wall and the inner edge of the outer annular wall; the outer peripheral surface of the longitudinal annular wall is sealed and matched with the first through hole.

3. The body assembly of the handheld device according to claim 2, characterized in that: The outer seal also includes an inner cylinder extending backward from the inner edge of the inner annular wall, and the outer shaft hole is also formed on the inner wall surface of the inner cylinder; The fixing seat is provided with an inner through hole for the driving shaft to pass through, and the front wall surface of the fixing seat is provided with an annular support wall on the periphery of the inner through hole, the support wall extends into the radial inner side of the longitudinal ring wall, and the support wall abuts against the inner circumferential surface of the longitudinal ring wall.

4. The body assembly of the handheld device according to claim 3, characterized in that: A clearance gap is formed between the inner wall surface of the inner through hole and the outer peripheral surface of the inner cylinder.

5. The body assembly of the handheld device according to claim 3 or 4, characterized in that: The inner wall surface of the inner through hole is provided with an annular sealing groove, and the sealing groove has a front wall surface and a rear wall surface which are opposite to each other in the axial direction; The body assembly of the handheld device also includes an inner seal, which is arranged in the inner through hole and extends into the sealing groove. The inner seal is respectively sealed with the front wall surface and the rear wall surface and can be rotatably matched; the inner seal is provided with an inner shaft hole that is sealed with the drive shaft and fixedly sleeved.

6. The body assembly of the handheld device according to claim 5, characterized in that: The inner seal and the inner wall surface of the sealing groove are combined to form a sealed cabin. The body component of the handheld device also includes lubricating oil filled in the sealed cabin. The lubricating oil forms an oil seal interface between the inner seal and the front wall surface, and between the inner seal and the rear wall surface.

7. The body assembly of the handheld device according to claim 6, characterized in that: The fixing seat includes a base and a bracket fixedly connected to the base, the base and the bracket enclose the inner via hole and the sealing groove, the inner via hole includes a rear opening opened in the base and a front opening opened in the bracket, the front wall surface and the supporting wall of the sealing groove are formed on the bracket, and the rear wall surface of the sealing groove is formed on the base.

8. The body assembly of the handheld device according to claim 7, characterized in that: The outer seal also includes an outer cylinder extending backward from the inner edge of the inner ring wall, and the inner lining also includes a limiting cylinder arranged on the periphery of the second through hole. The outer circumferential surface of the outer seal is sealed with the inner wall surface of the limiting cylinder, and the inner circumferential surface of the outer seal is limitedly abutted against the outer circumferential surface of the bracket.

9. The body assembly of the handheld device according to claim 8, characterized in that: The outer circumferential surface of the bracket is provided with a plurality of material reduction holes, the plurality of material reduction holes are arranged at intervals along the circumferential direction, and the material reduction holes are arranged axially away from the front end surface of the bracket.

10. The body assembly of the handheld device according to claim 7, characterized in that: One of the rear end surface of the bracket and the front end surface of the base is provided with a positioning groove, and the other is provided with a positioning protrusion matched with the positioning groove. The base and the bracket are fixed by an ultrasonic welding process.

11. The body assembly of the handheld device according to any one of claims 1 to 4, characterized in that: The outer wall is made of metal, the inner liner is made of plastic, an annular limiting groove is provided on the radial sealing surface, and a limiting convex ring matched with the limiting groove is provided on the front end surface of the outer sealing component.

12. An electric toothbrush, characterized in that: The invention comprises a motor and a body assembly of the handheld device as described in any one of claims 1 to 11, wherein the motor is arranged in a cavity of the body shell, and the drive shaft is connected to a rotor of the motor.

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