Shaft sealing assembly, front-end waterproof assembly and host of handheld appliance

Abstract

The invention discloses a shaft sealing assembly of a handheld appliance, a front-end waterproof assembly and a host. The shaft sealing assembly of the handheld appliance comprises a central shaft, a front-end waterproof assembly and a host, the movable sealing assembly comprises a fixed seat and a movable sealing piece, the fixed seat is provided with a sleeving through hole, the inner circumferential surface of the sleeving through hole is provided with an annular sealing groove, and the sealing groove is provided with a front wall surface and a rear wall surface which are opposite in the axial direction; and the movable sealing piece is made of a flexible material, is arranged in the sleeving through hole and extends into the sealing groove, is provided with a fixed shaft hole which is sealed and fixedly sleeved with the central shaft, and is respectively sealed with the front wall surface and the rear wall surface and is in running fit with the front wall surface and the rear wall surface. Abrasion cannot be generated between the movable sealing piece and the center shaft, and the sealing effect is improved.

Description

Technical Field

[0001] The present application relates to the technical field of waterproofing for handheld appliances, and particularly to a shaft seal assembly, a front-end waterproof assembly and a main body for a handheld appliance. Background Art

[0002] Due to their small size, it is difficult to waterproof the moving parts of handheld appliances. An electric toothbrush is a typical handheld appliance, and the central axis of its movement continuously wears the waterproof seal, eventually leading to seal failure and water leakage. Once the seal fails, external stains such as toothpaste foam will fill the gap around the central axis and enter the internal cavity of the handle, resulting in product malfunction.

[0003] Previously, electric toothbrushes rotated forward and backward at a small angle to fit the vibration of the brush head, or were driven by a magnetic levitation motor to achieve the vibration of the brush head. Since the movement amplitude is small, the wear on the seal is also small.

[0004] Nowadays, handheld appliances need to drive the working head with a larger rotation stroke and a higher frequency of forward and backward rotation switching. For example, an electric toothbrush needs to drive the brush head with a larger amplitude of movement to improve the brushing effect, or rotate 360 degrees to clean the tongue coating. However, the existing technology is difficult to meet the above new development requirements, resulting in the technical problems of short waterproof life of the central axis and high product after-sales rate. Summary of the Invention

[0005] The main purpose of the present application is to propose a front-end waterproof assembly for a handheld appliance and a main body of the handheld appliance, aiming to solve the technical problems that the waterproof life of the shaft seal assembly of the existing handheld appliance is short and it is difficult to adapt to the central axis working with a larger rotation stroke and a higher forward and backward rotation switching frequency.

[0006] To achieve the above object, the shaft seal assembly of the handheld appliance proposed in the present application includes:

[0007] A central axis; and

[0008] A movable seal assembly, the movable seal assembly includes a fixed seat and a dynamic seal, wherein,

[0009] The fixed seat is provided with a socket through-hole, and an annular seal groove is provided on the inner peripheral surface of the socket through-hole. The seal groove has a front wall surface and a rear wall surface that are axially opposite;

[0010] The dynamic seal is made of a flexible material. The dynamic seal is disposed in the socket through-hole and extends into the seal groove. The dynamic seal is provided with a fixed shaft hole that is sealed and fixedly sleeved with the central axis. The dynamic seal is respectively sealed and rotatably engaged with the front wall surface and the rear wall surface.

[0011] Preferably, a spacing is formed between the outer peripheral surface of the dynamic seal and the inner peripheral surface of the seal groove, and the dynamic seal and the fixed seat enclose to form a seal chamber located in the inner cavity of the seal groove.

[0012] Preferably, the movable seal assembly further includes an oil-based sealant filled in the seal chamber, and the oil-based sealant forms oil seal interfaces between the dynamic seal and the front wall surface, and between the dynamic seal and the rear wall surface.

[0013] Preferably, a front annular protrusion is provided on the outer periphery of the fixed shaft hole on the front end face of the dynamic seal, and the front annular protrusion is in sealed and rotatable fit with the front wall surface; a rear annular protrusion is provided on the outer periphery of the fixed shaft hole on the rear end face of the dynamic seal, and the rear annular protrusion is in sealed and rotatable fit with the rear wall surface.

[0014] Preferably, the front wall surface and / or the rear wall surface is a high-gloss surface, and its friction coefficient is less than the friction coefficient of the outer surface of the fixed seat.

[0015] Preferably, the dynamic seal is axially pre-pressed and fitted with the front wall surface and the rear wall surface respectively.

[0016] Preferably, the movable seal assembly further includes an annular clamp, the annular clamp is sleeved on the outer peripheral surface of the dynamic seal, and the annular clamp is in a tight fit with the dynamic seal in the radial direction.

[0017] Preferably, an annular limiting groove is provided on the outer peripheral surface of the dynamic seal, and the annular clamp is arranged in the limiting groove.

[0018] Preferably, the annular clamp is a spiral spring, and the front and rear ends of the annular clamp are elastically abutted against the axially opposite side wall surfaces of the limiting groove respectively.

[0019] Preferably, the fixed seat includes a base and a front cover fixedly connected to the base, the base and the front cover enclose to form the socket through-hole and the seal groove, the socket through-hole includes a rear opening formed in the base and a front opening formed in the front cover, the front wall surface of the seal groove is formed on the front cover, and the rear wall surface of the seal groove is formed on the base.

[0020] Preferably, the axial interference amount between the dynamic seal and the fixed seat is [0.1%, 0.5%].

[0021] Preferably, the base includes a sealing cylinder, the inner peripheral surface of the seal groove is formed on the sealing cylinder, and an annular groove is provided on the inner wall surface at the front end of the sealing cylinder; the front cover includes a cover plate and an inner stop, the cover plate covers the front open end of the sealing cylinder, the inner stop is annular and protrudes from the rear side surface of the cover plate, and the inner stop is adaptively fitted with the annular groove.

[0022] Preferably, the dynamic seal is made of rubber or silica gel; the base and the front cover are both made of plastic, and the rear end face of the inner stop is ultrasonically welded and fixed to the inner wall surface of the annular groove.

[0023] Preferably, an outer limiting plane is provided on the outer peripheral surface of the inner stop, and an inner limiting plane adapted to fit the outer limiting plane is provided on the inner peripheral surface of the annular groove.

[0024] Preferably, the base further includes a positioning protrusion provided on the front end face of the sealing cylinder, and a positioning groove adapted to the positioning protrusion is provided on the outer edge of the front cover.

[0025] Preferably, the positioning protrusion extends axially and protrudes from the outer peripheral surface of the sealing cylinder, and a slot adapted to the positioning protrusion is provided on the inner wall surface of the static seal.

[0026] The present application also provides a front-end waterproof assembly for a handheld appliance, including:

[0027] A housing having an internal cavity formed therein, and a sealing through-hole communicating with the cavity is provided on the front end face of the housing;

[0028] A static seal provided in the sealing through-hole and sealingly cooperating with the sealing through-hole, and the static seal is provided with a movable shaft hole communicating with the cavity; and

[0029] The shaft seal assembly for a handheld appliance as described above, wherein,

[0030] A central shaft is inserted through the movable shaft hole and extends outward from the housing, and the central shaft is sealingly and rotatably engaged with the movable shaft hole;

[0031] The movable seal assembly is provided in the cavity and is located behind the static seal, and the fixed seat is fixedly arranged relative to the housing.

[0032] Preferably, the static seal has an annular sealing surface arranged backward, and the annular sealing surface is formed around the movable shaft hole; the front side surface of the fixed seat is in sealing contact with the annular sealing surface.

[0033] Preferably, the fixed seat and the static seal are in a tight fit in the axial direction.

[0034] Preferably, the outer peripheral surface of the fixed seat is provided with a positioning protrusion extending axially, and a slot adapted to the positioning protrusion is provided on the inner wall surface of the static seal.

[0035] The present application also provides a main body of a handheld appliance, including a handle and a motor;

[0036] The main body of the handheld appliance further includes the shaft seal assembly of the handheld appliance as described above. The central shaft is a part of the rotor of the motor, and the fixed seat is fixedly arranged relative to the handle; or

[0037] The main body of the handheld appliance further includes the front-end waterproof assembly of the handheld appliance as described above. The handle is the housing, the motor is arranged in the cavity of the housing, and the central shaft is a part of the rotor of the motor.

[0038] In the shaft seal assembly of the handheld appliance of the present invention, two seals are respectively formed between the dynamic seal and the fixed seat on the front wall surface and the rear wall surface of the seal groove. The dynamic seal rotates with the central shaft. Therefore, there is no wear between the dynamic seal and the central shaft. Moreover, by transferring the movable sealing interface to the dynamic seal, the sealing area is increased, the sealing effect is improved, the waterproof life of the shaft seal assembly of the handheld appliance is extended, and the after-sales repair rate of the product is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0040] Figure 1 FIG. 15 is a front view structural diagram of a partial structure of an embodiment of the front-end waterproof assembly of the handheld appliance of the present invention;

[0041] Figure 2 is Figure 1 a sectional structural diagram along line II-II in FIG. 15;

[0042] Figure 3 is Figure 1 a composite diagram of an exploded view of a partial structure and a sectional structural diagram along line II-II in FIG. 15;

[0043] Figure 4 is Figure 3 an enlarged structural diagram of the dynamic seal in FIG. 15;

[0044] Figure 5 is Figure 1 an exploded structural diagram of a partial structure in FIG. 15;

[0045] Figure 6 is Figure 5 an enlarged structural diagram of the movable seal assembly in FIG. 15;

[0046] Figure 7 is Figure 1 an exploded structural diagram of a partial structure in FIG. 15 from another angle;

[0047] Figure 8 For Figure 7 the enlarged structural schematic diagram of the movable sealing assembly in the middle;

[0048] Figure 9 This is the three-dimensional structural schematic diagram of an embodiment of the main body of the handheld device of the present invention. Detailed implementation manners

[0049] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with 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. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0050] Referring to Figures 1 to 8 , in one embodiment, the shaft sealing assembly of the handheld device is applied to the front-end waterproof assembly 200 of the handheld device. The shaft sealing assembly of the handheld device includes:

[0051] a central shaft 30; and

[0052] a movable sealing assembly 40. The movable sealing assembly 40 includes a fixed seat 50 and a dynamic seal 60. Among them,

[0053] the fixed seat 50 is provided with a socket through hole 51. An annular sealing groove 52 is provided on the inner peripheral surface of the socket through hole 51. The sealing groove 52 has an axially opposite front wall surface 521 and a rear wall surface 522;

[0054] the dynamic seal 60 is made of a flexible material. The dynamic seal 60 is disposed in the socket through hole 51 and extends into the sealing groove 52. The dynamic seal 60 is provided with a fixed shaft hole 61 that is sealed and fixedly sleeved with the central shaft 30. The dynamic seal 60 is respectively sealed and rotatably engaged with the front wall surface 521 and the rear wall surface 522.

[0055] In this embodiment, the dynamic seal 60 is usually made of a flexible material, such as rubber, silicone, etc.

[0056] The central shaft 30 is used to play a role in connection and transmission. For example, in the embodiment applied to an electric toothbrush, the front end of the central shaft 30 is used to install the toothbrush head, and the rear end forms a part of the motor rotor. It can be understood that the central shaft 30 and the motor rotor can be separately provided. For example, a transmission mechanism can be added between the two.

[0057] Since the fixed seat 50 needs to play a role in support and limitation, the fixed seat 50 is usually made of a hard material, such as hard glue. The specific manufacturing process can adopt an injection molding process.

[0058] The sealing groove 52 and the dynamic seal 60 cooperate to form a closed space to ensure the sealing effect. Since the dynamic seal 60 also needs to be rotatably engaged with the front wall surface 521 and the rear wall surface 522 of the sealing groove 52.

[0059] The front-end waterproof assembly 200 of the handheld device of the present invention forms two seals on the front wall surface 521 and the rear wall surface 522 of the sealing groove 52 through the dynamic seal 60 and the fixed seat 50 respectively, and the dynamic seal 60 rotates with the central axis 30. Therefore, there is no wear between the dynamic seal 60 and the central axis 30, and by transferring the movable sealing interface to the dynamic seal 60, the sealing area is increased, the sealing effect is improved, and further, the waterproof life of the shaft seal assembly of the handheld device is extended, and the after-sales repair rate of the product is reduced.

[0060] Furthermore, a gap is formed between the outer peripheral surface of the dynamic seal 60 and the inner peripheral surface of the sealing groove 52, so that the friction between the dynamic seal 60 and the fixed seat 50 can be reduced. The dynamic seal 60 and the fixed seat 50 enclose a sealing chamber 70 located in the inner cavity of the sealing groove 52. In this way, the existing substances in the sealing chamber 70, such as air, oil, etc., can also play a role in blocking the invading stains.

[0061] Furthermore, the movable seal assembly 40 further includes an oil-based sealing material filled in the sealing chamber 70. The oil-based sealing material forms an oil seal interface between the dynamic seal 60 and the front wall surface 521, and between the dynamic seal 60 and the rear wall surface 522. In this embodiment, by filling the oil-based sealing material in the sealing chamber 70, not only can the friction be further reduced and thus the wear be reduced, but also the sealing effect can be improved by forming an additional oil seal interface.

[0062] Furthermore, a front annular protrusion 62 is provided on the front end surface of the dynamic seal 60 around the fixed shaft hole 61. The front annular protrusion 62 is in sealed and rotatable engagement with the front wall surface 521; a rear annular protrusion 63 is provided on the rear end surface of the dynamic seal 60 around the fixed shaft hole 61. The rear annular protrusion 63 is in sealed and rotatable engagement with the rear wall surface 522.

[0063] In this embodiment, after the oil seal interface is formed, the contact portion between the dynamic seal 60 and the inner wall surface of the sealing groove 52 is changed to an annular protrusion, such as the front annular protrusion 62 and the rear annular protrusion 63. In this way, without reducing the sealing effect, the friction can be reduced by locally reducing the contact area, and thus the wear can be reduced.

[0064] Further, in order to reduce the frictional force, both the front wall surface 521 and the rear wall surface 522 of the sealing groove 52 are high-gloss surfaces, and their friction coefficients are smaller than the friction coefficient of the outer surface of the fixed seat 50. For example, the front wall surface 521 and the rear wall surface 522 of the sealing groove 52 are smoother than the outer surface of the fixed seat 50. Specifically, the friction coefficients of both the front wall surface 521 and the rear wall surface 522 are in the range of [0.05, 0.1].

[0065] Further, the dynamic seal 60 is axially pre-compressed and fitted with the front wall surface 521 and the rear wall surface 522 respectively. In this embodiment, the elastic deformation of the dynamic seal 60 can be utilized to compensate and fill the axial clearance caused by vibration, so as to ensure that the positive pressure required for sealing is greater than a preset threshold. Preferably, the axial interference amount between the dynamic seal 60 and the fixed seat 50 is in the range of [0.1%, 0.5%], so that the rotational resistance of the central shaft 30 can be smaller while achieving the preset sealing effect.

[0066] Further, the movable seal assembly 40 further includes an annular clamp 80. The annular clamp 80 is sleeved on the outer peripheral surface of the dynamic seal 60, and the annular clamp 80 is tightly fitted with the dynamic seal 60 in the radial direction.

[0067] In this embodiment, the setting of the annular clamp 80 can improve the fixing and sealing effect between the dynamic seal 60 and the central shaft 30. In addition, the radial pressure applied by the annular clamp 80 will also force the dynamic seal 60 to deform axially, so as to better ensure the axial pre-compression fit between the dynamic seal 60 and the front wall surface 521 and the rear wall surface 522 respectively.

[0068] Further, an annular limiting groove 64 is provided on the outer peripheral surface of the dynamic seal 60, and the annular clamp 80 is arranged in the limiting groove 64. In this way, the annular clamp 80 is not easily detached from the dynamic seal 60, which is convenient for integral assembly and improves the assembly efficiency.

[0069] Further, the annular clamp 80 is a spiral spring, and the front and rear ends of the annular clamp 80 are elastically abutted against the axially opposite side wall surfaces of the limiting groove 64 respectively.

[0070] In this embodiment, the spiral spring is a standard part, which is easy to obtain and has a low cost. The annular clamp 80 is abutted against the axially opposite side wall surfaces of the limiting groove 64 respectively, which on the one hand is not easy to loosen, and on the other hand can cause the side wall of the limiting groove 64 to turn outwards, so as to be more conducive to the axial pre-compression fit between the dynamic seal 60 and the front wall surface 521 and the rear wall surface 522 respectively.

[0071] Further, the fixing base 50 includes a base 53 and a front cover 57 fixedly connected to the base 53. The base 53 and the front cover 57 enclose a socket through-hole 51 and a sealing groove 52. The socket through-hole 51 includes a rear opening 54 formed in the base 53 and a front opening 581 formed in the front cover 57. The front wall surface 521 of the sealing groove 52 is formed in the front cover 57, and the rear wall surface 522 of the sealing groove 52 is formed in the base 53.

[0072] In this embodiment, since the overall size of the fixing base 50 is small and the shape of the sealing groove 52 is not suitable for direct die-casting molding, that is, it cannot be demolded in a single direction. Therefore, the fixing base 50 is formed by connecting the split base 53 and the front cover 57. This can reduce the process cost of forming the inner cavity of the fixing base 50. For example, the base 53 and the front cover 57 are respectively formed by metal die-casting and then thread-connected or welded; or both the base 53 and the front cover 57 are made of plastic, and the two are fixed by ultrasonic welding or dotting.

[0073] Further, the base 53 includes a sealing cylinder 55. The inner peripheral surface of the sealing groove 52 is formed on the sealing cylinder 55. An annular groove 551 is provided on the inner wall surface of the front end of the sealing cylinder 55. The front cover 57 includes a cover plate 58 and an inner stop 59. The cover plate 58 covers the front open end of the sealing cylinder 55. The inner stop 59 is annular and protrudes from the rear side surface of the cover plate 58. The inner stop 59 is fitted and engaged with the annular groove 551, so that the base 53 and the front cover 57 are not easily displaced laterally. Preferably, the dynamic seal 60 is made of rubber or silica gel; both the base 53 and the front cover 57 are made of plastic, and the rear end surface of the inner stop 59 and the inner wall surface of the annular groove 551 are ultrasonically welded. Thus, even if the dynamic seal 60 contacts the base 55 and the front cover 57, since the material of the seal 60 is different from that of the base 55 and the front cover 57, the seal 60 will not adhere to the base 55 and the front cover 57 during the ultrasonic welding process.

[0074] Further, an outer limiting plane 591 is provided on the outer peripheral surface of the inner stop 59, and an inner limiting plane 552 adapted to fit with the outer limiting plane is provided on the inner peripheral surface of the annular groove 551, so as to prevent the front cover 57 from rotating relative to the base 53. Specifically, in the ultrasonic welding process, the limiting structure for preventing rotation between the front cover 57 and the base 53 is beneficial to improving the bonding efficiency.

[0075] Further, the base 53 further includes a positioning protrusion 56 provided on the front end surface of the sealing cylinder 55, and a positioning groove 582 adapted to the positioning protrusion 56 is provided on the outer edge of the front cover 57.

[0076] In this embodiment, the cooperation between the positioning protrusion 56 and the positioning groove 582 can form multi-level circumferential direction limiting, so that the limiting cooperation between the base 53 and the front cover 57 is more stable. In addition, since the positioning protrusion 56 and the positioning groove 582 are located in easily observable positions, the cooperation between the positioning protrusion 56 and the positioning groove 582 can also guide the outer limiting plane 591 to fit with the inner limiting plane 552.

[0077] Further, the positioning protrusion 56 extends axially and protrudes from the outer peripheral surface of the sealing cylinder 55. A slot 22 adapted to the positioning protrusion 56 is provided on the inner wall surface of the static seal 20. In this way, the circumferential limiting of the base 53 is realized, which not only simplifies the related assembly structure, but also improves the structural strength of the positioning protrusion 56 itself. The front end of the positioning protrusion 56 can also be located further radially outward, so that the fitting area between the cover plate 58 and the front end surface of the sealing cylinder 55 can be increased.

[0078] Further, the static seal 20 has an annular sealing surface arranged backward, and the annular sealing surface is formed around the movable shaft hole 21; the front side surface of the fixed seat 50 is in sealing fit with the annular sealing surface, which can improve the sealing performance of the lateral path. Preferably, the fixed seat 50 and the static seal 20 are in a tight fit in the axial direction, so that the possible gaps generated during vibration can be compensated by elastic deformation.

[0079] Please refer to again Figures 1 to 8 , this application also proposes a front-end waterproof assembly 200 for a handheld appliance, including:

[0080] A housing 10, with a cavity 11 formed inside, and a sealing through hole 12 communicating with the cavity 11 is provided on the front end surface of the housing 10;

[0081] A static seal 20, arranged in the sealing through hole 12 and in sealing cooperation with the sealing through hole 12, and the static seal 20 is provided with a movable shaft hole 21 communicating with the cavity 11; and

[0082] The shaft seal assembly of the handheld appliance as described above, wherein,

[0083] A central shaft 30, passing through the movable shaft hole 21 and extending outward from the housing 10, and the central shaft 30 is in sealing and rotatable cooperation with the movable shaft hole 21;

[0084] A movable seal assembly 40 is arranged in the cavity and behind the static seal 20, and the fixed seat 50 is fixedly arranged relative to the housing 10.

[0085] In this embodiment, the housing 10 provides support and protection for the internal components thereof. The housing 10 can only be used for installing the seal assembly and the transmission assembly, or can also provide a holding function together.

[0086] The static seal 20 and the dynamic seal 60 are usually made of flexible materials, such as rubber, silica gel, etc. To improve the sealing effect, multiple annular protrusions for forming wrinkles can be provided on the inner wall surface of the movable shaft hole 21.

[0087] For the specific structure of the shaft seal assembly of the handheld appliance, refer to the above embodiments. Since this electric toothbrush adopts all the technical solutions of the above embodiments, it also has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated one by one here.

[0088] The central shaft 30 is used for connection and transmission. For example, in the embodiment applied to an electric toothbrush, the front end of the central shaft 30 is used to install the brush head, and the rear end forms a part of the motor rotor. It can be understood that the central shaft 30 and the motor rotor can be separately arranged. For example, a transmission mechanism can be added between the two.

[0089] The fixed seat 50 can be directly fixedly connected to the housing 10, or can be fixedly arranged relative to the housing 10 by clamping the housing 10 with other components. Since the fixed seat 50 needs to play a role of support and limit, the fixed seat 50 is usually made of a hard material, such as hard rubber, and the specific manufacturing process can adopt an injection molding process.

[0090] The cooperation between the seal groove 52 and the dynamic seal 60 can form a closed space to ensure the sealing effect. Since the dynamic seal 60 also needs to be rotatably matched with the front wall surface 521 and the rear wall surface 522 of the seal groove 52, in order to reduce the friction force, both the front wall surface 521 and the rear wall surface 522 of the seal groove 52 are smooth surfaces, that is, the so-called high-gloss surfaces.

[0091] The front-end waterproof component 200 of the handheld appliance of the present invention can form an outer seal by setting the static seal 20, and form an inner seal by adding the movable seal assembly 40. Specifically, the dynamic seal 60 and the fixed seat 50 respectively form two seals on the front wall surface 521 and the rear wall surface 522 of the seal groove 52, and the dynamic seal 60 rotates with the central shaft 30. Therefore, there is no wear between the dynamic seal 60 and the central shaft 30, and by transferring the movable seal interface to the dynamic seal 60, the sealing area is increased, the sealing effect is improved, and further the front-end waterproof life of the handheld appliance is extended, and the after-sales repair rate of the product is reduced.

[0092] Please refer to Figure 9 , this application also proposes a main body 100 of a handheld appliance, including a handle and a motor (not shown in the figure);

[0093] The main body of the handheld appliance further includes the shaft seal assembly of the handheld appliance as described above, the central shaft is a part of the rotor of the motor, and the fixed seat is fixedly arranged relative to the handle; or

[0094] The main body of the handheld device further includes the front-end waterproof assembly of the handheld device as described above. The handle is a housing, and the motor is disposed in the cavity of the housing. The central shaft is part of the rotor of the motor.

[0095] In this embodiment, the main body of the handheld device can be the main body of an electric toothbrush as shown in Figure 9 or a handheld device with its functions, such as an electric hair curler. The handle can provide support and protection for its internal parts and can also provide a holding function for the user. The motor is used to provide a power source for the movement of the central shaft 30. For the specific structures of the shaft seal assembly of the handheld device and the front-end waterproof assembly 200 of the handheld device, refer to the above embodiments. Since this electric toothbrush adopts all the technical solutions of the above 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.

[0096] 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 recorded in the foregoing embodiments, or perform equivalent replacements for 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 embodiments of the present application.

Claims

1. An axial seal assembly for a handheld appliance, characterized in that, it comprises: a central shaft; and a movable seal assembly, the movable seal assembly comprising a fixed seat and a dynamic seal, wherein, the fixed seat is provided with a socket through-hole, an annular seal groove is provided on the inner peripheral surface of the socket through-hole, and the seal groove has an axially opposite front wall surface and a rear wall surface; the dynamic seal is made of a flexible material, the dynamic seal is arranged in the socket through-hole and extends into the seal groove, the dynamic seal is provided with a fixed shaft hole that is sealed and fixedly sleeved with the central shaft, and the dynamic seal is respectively in sealed and rotatable fit with the front wall surface and the rear wall surface.

2. The axial seal assembly for a handheld appliance according to claim 1, characterized in that, a gap is formed between the outer peripheral surface of the dynamic seal and the inner peripheral surface of the seal groove, and a sealed chamber located in the inner cavity of the seal groove is formed by enclosing the dynamic seal and the fixed seat.

3. The axial seal assembly for a handheld appliance according to claim 2, characterized in that, the movable seal assembly further comprises an oil-based sealant filled in the sealed chamber, and the oil-based sealant forms an oil seal interface between the dynamic seal and the front wall surface, and between the dynamic seal and the rear wall surface.

4. The axial seal assembly for a handheld appliance according to claim 3, characterized in that, a front annular protrusion is provided on the front end surface of the dynamic seal around the fixed shaft hole, and the front annular protrusion is in sealed and rotatable fit with the front wall surface; a rear annular protrusion is provided on the rear end surface of the dynamic seal around the fixed shaft hole, and the rear annular protrusion is in sealed and rotatable fit with the rear wall surface.

5. The axial seal assembly for a handheld appliance according to any one of claims 1-4, characterized in that, the front wall surface and / or the rear wall surface is a high-gloss surface, and its coefficient of friction is less than the coefficient of friction of the outer surface of the fixed seat.

6. The axial seal assembly for a handheld appliance according to claim 1, characterized in that, the dynamic seal is respectively in axial preloading fit with the front wall surface and the rear wall surface.

7. The axial seal assembly for a handheld appliance according to claim 6, characterized in that, the movable seal assembly further comprises an annular clamp, the annular clamp is sleeved on the outer peripheral surface of the dynamic seal, and the annular clamp is in a tight fit with the dynamic seal in the radial direction.

8. The axial seal assembly for a handheld appliance according to claim 7, characterized in that, an annular limiting groove is provided on the outer peripheral surface of the dynamic seal, and the annular clamp is arranged in the limiting groove.

9. The axial seal assembly for a handheld appliance according to claim 8, characterized in that, the annular clamp is a spiral spring, and the front and rear ends of the annular clamp are respectively in elastic abutment with the axially opposite side wall surfaces of the limiting groove.

10. The axial seal assembly for a handheld appliance according to any one of claims 6-9, characterized in that, the axial interference amount between the dynamic seal and the fixed seat is [0.1%, 0.5%].

11. The axial seal assembly for a handheld appliance according to claim 1, characterized in that, The fixing base includes a base and a front cover fixedly connected to the base. The base and the front cover enclose to form the socket through-hole and the sealing groove. The socket through-hole includes a rear opening formed in the base and a front opening formed in the front cover. The front wall surface of the sealing groove is formed on the front cover, and the rear wall surface of the sealing groove is formed on the base.

12. The shaft seal assembly of the handheld appliance according to claim 11, wherein, the base includes a sealing cylinder. The inner peripheral surface of the sealing groove is formed on the sealing cylinder. An annular groove is provided on the inner wall surface at the front end of the sealing cylinder; the front cover includes a cover plate and an inner stop. The cover plate covers the front open end of the sealing cylinder. The inner stop is annular and protrudes from the rear side surface of the cover plate. The inner stop is fitted and engaged with the annular groove.

13. The shaft seal assembly of the handheld appliance according to claim 12, wherein, the dynamic seal is made of rubber or silica gel; both the base and the front cover are made of plastic, and the rear end surface of the inner stop is ultrasonically welded and fixed to the inner wall surface of the annular groove.

14. The shaft seal assembly of the handheld appliance according to claim 12 or 13, wherein, an outer limiting plane is provided on the outer peripheral surface of the inner stop, and an inner limiting plane adapted to fit with the outer limiting plane is provided on the inner peripheral surface of the annular groove.

15. The shaft seal assembly of the handheld appliance according to claim 12, wherein, the base further includes a positioning protrusion provided on the front end surface of the sealing cylinder, and a positioning groove adapted to the positioning protrusion is provided on the outer edge of the front cover.

16. The shaft seal assembly of the handheld appliance according to claim 15, wherein, the positioning protrusion extends axially and protrudes from the outer peripheral surface of the sealing cylinder, and a slot adapted to the positioning protrusion is provided on the inner wall surface of the static seal.

17. A front-end waterproof assembly of a handheld appliance, wherein, comprising: a housing with a cavity formed inside. A sealing through-hole communicating with the cavity is provided on the front end surface of the housing; a static seal provided in the sealing through-hole and sealingly cooperating with the sealing through-hole. The static seal is provided with a movable shaft hole communicating with the cavity; and the shaft seal assembly of the handheld appliance according to any one of claims 1-16, wherein, a central shaft passes through the movable shaft hole and extends out of the housing. The central shaft is sealingly and rotatably fitted with the movable shaft hole; the movable seal assembly is provided in the cavity and located at the rear side of the static seal, and the fixing base is fixedly arranged relative to the housing.

18. The front-end waterproof assembly of the handheld appliance according to claim 17, wherein, the static seal has an annular sealing surface arranged backward, and the annular sealing surface is formed around the movable shaft hole; the front side surface of the fixing base is in sealing fit with the annular sealing surface.

19. The front-end waterproof assembly of the handheld appliance according to claim 18, wherein, the fixing base and the static seal are in a tight fit in the axial direction.

20. The front-end waterproof assembly of the handheld appliance according to any one of claims 17-19, wherein, The outer peripheral surface of the fixed seat is provided with a positioning protrusion extending along the axial direction, and the inner wall surface of the static seal is provided with a slot adapted to the positioning protrusion.

21. A main body of a handheld appliance, comprising a handle and a motor; Characterized in that, The main body of the handheld appliance further includes a shaft seal assembly of the handheld appliance as described in any one of claims 1-16, the central shaft is a part of the rotor of the motor, and the fixed seat is fixedly arranged relative to the handle; or The main body of the handheld appliance further includes a front-end waterproof assembly of the handheld appliance as described in any one of claims 17-20, the handle is the housing, the motor is arranged in the cavity of the housing, and the central shaft is a part of the rotor of the motor.

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