A top cover mechanism for an electronic water vapor atomizer

Abstract

This utility model relates to the field of electronic water vapor atomizer technology, and more particularly to an upper cover mechanism for an electronic water vapor atomizer, including an upper cover shell and a heating head. The upper cover shell includes an upper cover body and an upper connecting seat. A positioning mechanism is provided between the upper cover body and the upper connecting seat, and the upper cover body is connected to the outside of the upper connecting seat through the positioning mechanism. The heating head is fixed to the upper connecting seat. An air inlet groove is provided through the upper cover shell, and an air guide channel is provided through the heating head, which is connected to the air inlet groove. This utility model allows for precise and convenient assembly of the upper cover body with the upper connecting seat via the positioning mechanism, facilitating disassembly and maintenance. The heating head being fixed to the upper connecting seat makes the structure compact and stable, facilitating heat transfer. The air guide channel communicating with the air inlet groove ensures smooth airflow into the heating head, improving the atomization effect and preventing cold air from affecting the temperature rise, atomization, and taste of the inhaled material.

Description

Technical Field

[0001] This utility model relates to the field of electronic water vapor atomizer technology, and in particular to an upper cover mechanism for an electronic water vapor atomizer. Background Technology

[0002] The primary function of an electronic hookah atomizer is to heat and atomize hookah materials (such as tobacco paste, tobacco, or e-liquid) into smoke for the user to inhale, thus simulating the smoking experience of traditional tobacco. Its working principle involves a battery-powered heater that heats the e-liquid to its vaporization temperature, forming smoke.

[0003] In the current market for electronic water vapor atomizers, the design of the top cover mechanism has many shortcomings. On the one hand, the assembly and connection of the top cover lacks precise positioning, making the assembly process cumbersome and prone to deviations. It is also difficult to disassemble accurately during subsequent maintenance, increasing production and maintenance costs.

[0004] On the other hand, the design of the gas flow channel is not scientifically sound, and the connection between the top cover mechanism and the atomizer main unit is poor, often resulting in obstructed gas flow. This not only affects the atomization effect of the hookah inhalation material, leading to unstable vapor production, but also reduces the user experience. Therefore, how to design a top cover mechanism for an electronic hookah atomizer that can achieve precise connection and ensure smooth gas flow has become a pressing technical problem to be solved in this field. Utility Model Content

[0005] The purpose of this utility model is to address the shortcomings of the existing technology by providing an upper cover mechanism for an electronic water vapor atomizer. The upper cover is precisely and conveniently assembled with the upper connecting seat via a positioning mechanism and is easy to disassemble and maintain. The heating head is fixed to the upper connecting seat, making the structure compact and stable and facilitating heat transfer. The air guide channel is connected to the air inlet slot to ensure that air enters the heating head smoothly, improving the atomization effect and preventing cold air from affecting the temperature rise, atomization, and taste of the inhaled material.

[0006] To achieve the above objectives, the present invention provides an upper cover mechanism for an electronic water vapor atomizer, comprising an upper cover shell and a heating head.

[0007] The upper cover shell includes an upper cover body and an upper connecting seat. A positioning mechanism is provided between the upper cover body and the upper connecting seat. The upper cover body is connected to the outside of the upper connecting seat through the positioning mechanism.

[0008] The heating head is fixed to the upper connecting seat;

[0009] The upper cover is provided with an air inlet slot, and the heating head is provided with an air guide channel, which is connected to the air inlet slot.

[0010] Preferably, the positioning mechanism includes a positioning strip disposed on the inner side of the upper cover body and a positioning hole disposed on the edge of the upper connecting seat, wherein the positioning strip is inserted into the positioning hole.

[0011] Preferably, a connecting strip is provided on the outer side of the heating head, and the connecting strip abuts against the outer side of the positioning hole.

[0012] Preferably, the heating head includes a heat insulation shell and a heat-conducting base, the heat-conducting base being connected to the lower part of the heat insulation shell, and a heat exchange cavity being provided between the heat-conducting base and the interior of the heat insulation shell;

[0013] The heat-conducting base has a heating chamber inside for installing the heater;

[0014] The heat insulation shell is provided with an air inlet for introducing gas into the heat exchange cavity, and the heat conduction seat is provided with an air outlet groove along the inner circumferential direction of the connection with the heat insulation shell for discharging gas out of the heat exchange cavity. The air inlet, the heat exchange cavity and the air outlet groove form the gas guiding channel.

[0015] Preferably, a radiator is provided on the heat-conducting base, and a secondary heat chamber for installing a heater is provided between the radiator and the heat-conducting base.

[0016] Preferably, the heat-conducting base is provided with a wire outlet groove corresponding to the heating cavity, and the heat insulation shell is provided with a clearance groove corresponding to the wire outlet groove;

[0017] The auxiliary heating cavity is provided with an outlet hole that communicates with the heating cavity;

[0018] The upper connector is provided with conductive electrodes.

[0019] Preferably, the air outlet groove includes an air inlet end and a diffuser end that are interconnected, and the air inlet end and the diffuser end are offset along the vertical direction of the heat-conducting base.

[0020] Preferably, a heat insulation cavity is provided between the heating head and the upper cover shell, and a sealing element is provided at the connection between the heat insulation cavity and the air inlet channel. The sealing element is provided with a limiting groove, and the upper cover body is provided with a limiting edge, which abuts against the limiting groove.

[0021] Preferably, a heat insulation component is provided inside the heat insulation cavity, one end of which abuts against the sealing component, and the other end of which abuts against the upper connecting seat.

[0022] Preferably, the upper connecting seat is provided with a magnetic nano-groove, and a permanent magnet is disposed in the magnetic nano-groove.

[0023] The beneficial effects of this utility model are as follows: The upper cover of this utility model is precisely and conveniently assembled with the upper connecting seat through the positioning mechanism and is easy to disassemble and maintain. The heating head is fixed to the upper connecting seat, making the structure compact and stable and facilitating heat transfer. The air guide channel is connected to the air inlet slot to ensure that air enters the heating head smoothly, improves the atomization effect, and avoids cold air affecting the temperature rise, atomization and taste of the inhalation material. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the exploded structure of this utility model.

[0025] Figure 2 This is an exploded cross-sectional view of the present invention.

[0026] Figure 3 This is a cross-sectional structural diagram of the present invention.

[0027] The reference numerals in the figures include:

[0028] 1. Top cover shell; 11. Top cover body; 111. Limiting edge; 12. Upper connecting seat; 121. Magnetic slot; 13. Conductive electrode; 14. Heat insulation cavity; 15. Sealing element; 151. Limiting groove; 16. Heat insulation element; 161. Air gap groove; 17. Permanent magnet; 101. Air inlet groove;

[0029] 2. Heating head; 21. Connecting clip; 22. Heat insulation shell; 221. Air inlet; 222. Clearance groove; 23. Heat-conducting base; 231. Air outlet groove; 2311. Air inlet end; 2312. Diffuser end; 232. Cable outlet groove; 24. Heat exchange chamber; 25. Heating chamber; 26. Radiator; 27. Secondary heating chamber; 271. Cable outlet hole; 201. Air guide channel;

[0030] 3. Positioning mechanism; 31. Positioning strip; 32. Positioning hole. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings.

[0032] like Figures 1 to 3 As shown, the upper cover mechanism of an electronic water vapor atomizer of this utility model includes an upper cover shell 1 and a heating head 2. The upper cover shell 1 includes an upper cover body 11 and an upper connecting seat 12. A positioning mechanism 3 is provided between the upper cover body 11 and the upper connecting seat 12. The upper cover body 11 is connected to the outside of the upper connecting seat 12 through the positioning mechanism 3. The heating head 2 is fixed to the upper connecting seat 12.

[0033] The upper cover 1 has an air inlet groove 101 through it, and the heating head 2 has an air guide channel 201 through it, which is connected to the air inlet groove 101.

[0034] Specifically, the upper cover 11 can be accurately and stably connected to the outside of the upper connecting seat 12 through the positioning mechanism 3. This makes the assembly of the upper cover 11 and the upper connecting seat 12 more precise and convenient, improves production efficiency, and also facilitates subsequent disassembly and maintenance, reducing maintenance costs.

[0035] The heating head 2 is directly fixed to the upper connecting seat 12, forming a stable integral structure between the heating head 2 and the upper cover 1. This fixing method makes the structure of the electronic water vapor atomizer more compact, reduces the shaking between components, improves the stability and reliability of the atomizer, and also facilitates heat transfer and concentration.

[0036] The air guide channel 201 is connected to the air inlet slot 101, forming a channel for gas flow. This ensures that external air can smoothly enter the interior of the heating head 2, providing sufficient air for the atomization process, which is beneficial to improving the atomization effect, making the smoke more uniform and dense, and enhancing the user experience. On the other hand, it avoids external cold air directly contacting the hookah smoking material, which would cause the hookah smoking material to cool down, affecting the temperature rise and atomization effect of the hookah smoking material and the atomized taste.

[0037] During production, the heating head 2 is first attached to the upper connecting seat 12 by snap-fit, screw fixing, or glue. The upper cover 11 is connected to the outside of the upper connecting seat 12 by the positioning mechanism 3, completing the assembly of the upper cover mechanism, which facilitates the production and maintenance of the atomizer.

[0038] The top cover mechanism is mounted on the atomizer body, with the heating head 2 positioned above the atomizing material. The air guide channel 201 connects to the air inlet slot 101, thus completing the gas flow. The heater heats the hookah material, atomizing it into smoke. When the user inhales, outside cold air enters the top cover mechanism through the air inlet slot 101 and then flows into the heating head 2 along the air guide channel 201. After heat exchange within the heating head 2, the outside air, along with the smoke, enters the user's mouth with the airflow, ensuring sufficient air supply during the atomization process.

[0039] like Figure 2 As shown, the positioning mechanism 3 in this embodiment includes a positioning strip 31 disposed on the inner side of the upper cover 11 and a positioning hole 32 disposed on the edge of the upper connecting seat 12, with the positioning strip 31 inserted into the positioning hole 32.

[0040] Specifically, a positioning strip 31 is provided on the inner side of the upper cover 11, and a positioning hole 32 is provided on the edge of the upper connecting seat 12. By inserting the positioning strip 31 into the positioning hole 32, precise positioning between the upper cover 11 and the upper connecting seat 12 is achieved. This positioning method makes the assembly of the upper cover 11 and the upper connecting seat 12 more precise, avoids deviations during the assembly process, and improves production efficiency; it also facilitates subsequent disassembly and maintenance, reducing maintenance costs.

[0041] In other embodiments, magnets with opposite magnetic properties are installed at corresponding positions on the upper cover 11 and the upper connecting seat 12. When the upper cover 11 approaches the upper connecting seat 12, the two will automatically attract each other due to the magnetic force, achieving initial positioning and connection.

[0042] like Figure 2 As shown, a connecting strip 21 is provided on the outer side of the heating head 2 in this embodiment, and the connecting strip 21 abuts against the outer side of the positioning hole 32.

[0043] Specifically, the heating head 2 is connected to the positioning hole 32 by mechanical interference between the connecting strip 21 and the outer side of the positioning hole 32, thereby fixing the heating head 2 to the upper connecting seat 12. This prevents the heating head 2 from rotating in the horizontal direction, avoiding misalignment between the heating head 2 and the upper connecting seat 12 due to rotation.

[0044] As shown in Figure 2, the heating head 2 in this embodiment includes a heat insulation shell 22 and a heat conduction seat 23. The heat conduction seat 23 is connected to the lower part of the heat insulation shell 22, and a heat exchange chamber 24 is provided between the heat conduction seat 23 and the interior of the heat insulation shell 22.

[0045] The heat-conducting base 23 has a heating chamber 25 inside for mounting the heater;

[0046] The heat insulation shell 22 is provided with an air inlet 221 for introducing gas into the heat exchange chamber 24, and the heat conduction seat 23 is provided with an air outlet groove 231 for discharging gas out of the heat exchange chamber 24 along the inner circumferential direction of the connection with the heat insulation shell 22. The air inlet 221, the heat exchange chamber 24 and the air outlet groove 231 form a gas guiding channel 201.

[0047] Specifically, the heating head 2 is designed as two parts: a heat insulation shell 22 and a heat-conducting base 23. The heat-conducting base 23 is connected to the lower part of the heat insulation shell 22. Utilizing the different thermal properties of the heat insulation shell 22 and the heat-conducting base 23, the heat insulation shell 22 prevents heat loss, while the heat-conducting base 23 is responsible for effectively transferring heat. The split design facilitates the separate processing, installation, and maintenance of the heat-conducting base 23 and the heat insulation shell 22, reducing production costs and maintenance difficulty.

[0048] A heat exchange cavity 24 is formed between the heat-conducting base 23 and the heat insulation shell 22, providing space for heat exchange between the gas and the heat-conducting base 23. When the gas enters the heat exchange cavity 24, it can fully contact the heat-conducting base 23 and absorb heat. The gas exchanges heat with the heat-conducting base 23 in the heat exchange cavity 24, and the temperature rises, which is beneficial for subsequent full mixing with the hookah smoking material and promotes atomization, making the smoke more uniform and rich.

[0049] A dedicated heating chamber 25 is provided inside the heat-conducting base 23, and the heater is installed inside the heating chamber 25, allowing the heat generated by the heater to be directly and efficiently transferred to the heat-conducting base 23. The heater is in close contact with the heat-conducting base 23, enabling rapid heat transfer and rapid heating of the heat-conducting base 23, thereby shortening the preheating time of the atomizer and improving its efficiency. Furthermore, the heater is separated from the air-guiding channel 201, ensuring stable and constant-temperature operation of the heater and reducing the impact of temperature changes in the heat exchange chamber 24 on the heater.

[0050] The air inlet 221 on the heat insulation shell 22 allows external gas to enter the heat exchange chamber 24, while the air outlet 231 on the heat-conducting base 23 discharges the gas that has undergone heat exchange from the heat exchange chamber 24. The air inlet 221, the heat exchange chamber 24, and the air outlet 231 together constitute the gas flow channel, namely the air guide channel 201. The design of the air guide channel 201 ensures that the gas can flow smoothly along a predetermined path, providing sufficient hot air for the atomization process, which is beneficial to improving atomization efficiency and quality.

[0051] like Figure 2 As shown, a heat sink 26 is provided on the heat-conducting base 23 in this embodiment, and a secondary heat chamber 27 for installing a heater is provided between the heat sink 26 and the heat-conducting base 23.

[0052] Specifically, a radiator 26 is added to the heat-conducting base 23. Utilizing the radiator 26's large heat dissipation area and good thermal conductivity, when the heat-conducting base 23 absorbs heat generated by the heater, it transfers some of the heat to the radiator 26. The radiator 26 then dissipates the heat through heat exchange with the surrounding air. This allows the gas to contact the radiator 26 within the heat exchange chamber 24, ensuring thorough heat exchange.

[0053] A heater is installed in the auxiliary heating chamber 27, making the heating head 2 a dual-heater design. The heat generated by the heater can be transferred to the heat conduction seat 23 to heat the water pipe smoking material, and some of the heat can also be transferred to the radiator 26 through the heat conduction seat 23 for gas heat exchange, thus optimizing the heat distribution and transfer path.

[0054] like Figure 3 As shown, in this embodiment, the heat-conducting base 23 is provided with a wire outlet groove 232 corresponding to the heating cavity 25, and the heat insulation shell 22 is provided with a relief groove 222 corresponding to the wire outlet groove 232;

[0055] The auxiliary heating cavity 27 is provided with a wire outlet hole 271 that communicates with the heating cavity 25;

[0056] The upper connector 12 is provided with a conductive electrode 13.

[0057] Specifically, the heater is installed inside the heating chamber 25 and needs to be connected to an external power source to obtain electrical energy. The cable outlet groove 232 and the clearance groove 222 cooperate to provide a reasonable lead-out channel for the heater's connection wire, so that the connection wire can be smoothly led out from inside the heating chamber 25, avoiding the connection wire from being messy distributed inside the heating chamber 25 or interfering with other components.

[0058] The auxiliary heating cavity 27 is provided with a wire outlet hole 271 that communicates with the heating cavity 25, so that the connecting wire of the heater of the auxiliary heating cavity 27 can enter the auxiliary heating cavity 27 from the heating cavity 25 through the wire outlet hole 271, ensuring that the connecting wire can pass smoothly through different cavities.

[0059] The conductive electrode 13 can be electrically connected to the heater's connecting wires and power supply components such as batteries, so that electrical energy can be smoothly transferred from the power source to the heater, providing the electrical energy required for the heater to operate.

[0060] like Figure 2 As shown, the air outlet groove 231 in this embodiment includes an air inlet end 2311 and a diffuser end 2312 that are connected to each other. The air inlet end 2311 and the diffuser end 2312 are offset along the vertical direction of the heat conduction seat 23.

[0061] Specifically, the air outlet 231 is provided with an air inlet 2311 and a diffuser 2312, which are connected to each other. The air inlet 2311 serves as the inlet for gas to enter the air outlet 231, while the diffuser 2312 serves as the outlet for gas to exit from the air outlet 231. The flow and diffusion of gas within the air outlet 231 allows the gas to mix more thoroughly with the atomized e-liquid, which is beneficial for forming a more uniform and delicate vapor, thus enhancing the user's vaping experience.

[0062] The inlet end 2311 and the diffuser end 2312 are offset along the vertical direction of the heat-conducting base 23, so that after the gas enters from the inlet end 2311, it needs to flow to the diffuser end 2312 along a certain angle and path. This offset arrangement increases the flow distance and time of the gas in the outlet groove 231, so that the gas can better exchange heat and mix with the surrounding environment.

[0063] like Figure 3 As shown, in this embodiment, a heat insulation cavity 14 is provided between the heating head 2 and the upper cover shell 1. A sealing element 15 is provided at the connection between the heat insulation cavity 14 and the air inlet channel 201 and the air inlet groove 101. The sealing element 15 is provided with a limiting groove 151. The upper cover body 11 is provided with a limiting edge 111. The limiting edge 111 abuts against the limiting groove 151.

[0064] Specifically, the heating head 2 generates a large amount of heat during operation. The presence of the heat insulation cavity 14 forms an air insulation layer between the heating head 2 and the upper cover 1. Since air is a poor conductor of heat, it effectively hinders heat transfer, reducing the conduction of heat generated by the heating head 2 to the upper cover 1. This prevents users from being burned by contact with the upper cover 1 during use, improving safety.

[0065] The seal 15 is elastic and can fill the gap at the joint, preventing gas from leaking from the joint between the air guide channel 201 and the air inlet groove 101. The seal 15 is typically made of elastic materials such as rubber or foamed silicone.

[0066] The sealing element 15 is positioned and fixed by the abutting engagement between the limiting edge 111 and the limiting groove 151. The limiting groove 151 restricts the movement of the sealing element 15 in the horizontal direction, while the limiting edge 111 prevents the sealing element 15 from dislodging from the predetermined position in the vertical direction, ensuring that the sealing element 15 can be accurately installed at the connection between the air guide channel 201 and the air inlet groove 101.

[0067] like Figure 3 As shown, in this embodiment, a heat insulation component 16 is provided in the heat insulation cavity 14. One end of the heat insulation component 16 abuts against the sealing component 15, and the other end of the heat insulation component 16 abuts against the upper connecting seat 12.

[0068] Specifically, the insulation component 16 can be made of aerogel felt, fiberglass cotton or foamed silicone, and the insulation component 16 further enhances the insulation effect.

[0069] One end of the heat insulation component 16 abuts against the sealing component 15. On the one hand, the position of the sealing component 15 can play a certain positioning role for the heat insulation component 16. On the other hand, it can also prevent heat from leaking from the gap between the sealing component 15 and the heat insulation component 16, further enhancing the overall heat insulation and sealing effect.

[0070] The other end of the heat insulation component 16 abuts against the upper connecting seat 12, which can ensure that the heat insulation component 16 will not shift and will always remain in an effective heat insulation position, while also better blocking heat from being transferred upward from the heating head 2.

[0071] Preferably, a spacer groove 161 is provided between the heat insulation component 16 and the outer wall of the heating head 2, so as to better prevent the heat of the heating head 2 from being conducted from the heat insulation component 16 to the upper cover 11.

[0072] like Figure 1 As shown, the upper connecting seat 12 in this embodiment is provided with a magnetic trough 121, and a permanent magnet 17 is provided in the magnetic trough 121.

[0073] Specifically, the magnetic slot 121 is a groove structure specially designed on the upper connecting seat 12 to accommodate the permanent magnet 17. By setting the magnetic slot 121, a fixed installation position can be provided for the permanent magnet 17, so that it can be stably placed on the upper connecting seat 12, while also providing a certain degree of protection for the permanent magnet 17, preventing it from being damaged by external collisions or pressure.

[0074] The upper connector 12 connects to the atomizer host without the need for additional mechanical connection structures, based on the principle of magnetic interaction of the permanent magnet 17.

[0075] The above description is only a preferred embodiment of this utility model. For those skilled in the art, there will be changes in the specific implementation method and application scope based on the idea of ​​this utility model. The content of this specification should not be construed as a limitation of this utility model.

Claims

1. A mechanism of an upper cover of an electronic hookah atomizer, characterized in that, It includes an upper cover (1) and a heating head (2). The upper cover shell (1) includes an upper cover body (11) and an upper connecting seat (12). A positioning mechanism (3) is provided between the upper cover body (11) and the upper connecting seat (12). The upper cover body (11) is connected to the outside of the upper connecting seat (12) through the positioning mechanism (3). The heating head (2) is fixed to the upper connecting seat (12); The upper cover (1) is provided with an air inlet groove (101), and the heating head (2) is provided with an air guide channel (201) inside, which is connected to the air inlet groove (101).

2. The upper cover mechanism of an electronic hookah atomizer according to claim 1, wherein, The positioning mechanism (3) includes a positioning strip (31) disposed on the inner side of the upper cover (11) and a positioning hole (32) disposed on the edge of the upper connecting seat (12), wherein the positioning strip (31) is inserted into the positioning hole (32).

3. The upper cap mechanism of an electronic shisha atomizer according to claim 2, wherein, A connecting strip (21) is provided on the outside of the heating head (2), and the connecting strip (21) abuts against the outside of the positioning hole (32).

4. The upper cover mechanism of an electronic hookah atomizer according to claim 1, wherein, The heating head (2) includes a heat insulation shell (22) and a heat conduction seat (23). The heat conduction seat (23) is connected to the lower part of the heat insulation shell (22), and a heat exchange chamber (24) is provided between the heat conduction seat (23) and the interior of the heat insulation shell (22). The heat-conducting base (23) is provided with a heating chamber (25) for installing a heater. The heat insulation shell (22) is provided with an air inlet (221) for introducing gas into the heat exchange chamber (24), and the heat conduction seat (23) is provided with an air outlet groove (231) for discharging gas from the heat exchange chamber (24) along the inner circumferential direction of the connection with the heat insulation shell (22). The air inlet (221), the heat exchange chamber (24) and the air outlet groove (231) form the air guiding channel (201).

5. The upper cap mechanism of an electronic shisha atomizer according to claim 4, wherein, A radiator (26) is provided on the heat-conducting base (23), and a secondary heat chamber (27) for installing a heater is provided between the radiator (26) and the heat-conducting base (23).

6. The upper cap mechanism of an electronic shisha atomizer according to claim 5, wherein, The heat-conducting base (23) is provided with a wire outlet groove (232) corresponding to the heating cavity (25), and the heat insulation shell (22) is provided with a clearance groove (222) corresponding to the wire outlet groove (232). The auxiliary heating cavity (27) is provided with an outlet hole (271) that communicates with the heating cavity (25). The upper connector (12) is provided with a conductive electrode (13).

7. The upper cap mechanism of an electronic shisha atomizer according to claim 4, wherein, The air outlet groove (231) includes an air inlet end (2311) and a diffuser end (2312) that are connected to each other. The air inlet end (2311) and the diffuser end (2312) are offset along the vertical direction of the heat-conducting base (23).

8. The upper cap mechanism of an electronic shisha atomizer according to claim 1, wherein, A heat insulation cavity (14) is provided between the heating head (2) and the upper cover shell (1). A sealing element (15) is provided at the connection between the heat insulation cavity (14) and the air inlet channel (201) and the air inlet groove (101). The sealing element (15) is provided with a limiting groove (151). The upper cover body (11) is provided with a limiting edge (111). The limiting edge (111) abuts against the limiting groove (151).

9. The upper cap mechanism of an electronic shisha atomizer according to claim 8, wherein, A heat insulation component (16) is provided inside the heat insulation cavity (14). One end of the heat insulation component (16) abuts against the sealing component (15), and the other end of the heat insulation component (16) abuts against the upper connecting seat (12).

10. The upper cap mechanism of an electronic shisha atomizer according to claim 1, wherein, The upper connecting seat (12) is provided with a magnetic trough (121), and a permanent magnet (17) is provided in the magnetic trough (121).

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