Laminated fan structure for seat air blowing and suction system

Abstract

The invention provides a stacked fan structure for a seat air blowing and suction system, which is characterized in that two fan assemblies are integrally mounted together, and each fan assembly is provided with an air port and an internal space; the inner spaces of the two fan assemblies are communicated. When one fan assembly works, the air port of the fan assembly serves as an air blowing port, and the air port of the other fan assembly serves as an air suction port. And the two fan assemblies are controlled to work respectively, so that the effect that the air suction mode and the air blowing mode are switched through one air opening is achieved. The internal structural design is simple, and the air leakage phenomenon is not prone to occurring; and meanwhile, an additional motor is not needed, so that the occupied space for mounting the motor is reduced, and the total weight of the structure is reduced.

Description

Technical Field

[0001] The present invention generally relates to the technical field of fans, and in particular to a cascading fan structure for a seat blowing and suction system. Background Art

[0002] Existing automobile seats are all equipped with ventilation devices. In order to meet more usage requirements, the existing ventilation devices are equipped with fan structures with two functions of blowing and sucking.

[0003] In order to realize the functions of blowing and sucking air, the existing fan structure has multiple air outlets, which are used for air intake and air exhaust when sucking air, and air intake and air exhaust when blowing air; and an additional wind shield structure is also provided. By controlling the switching state of the wind shield structure, the air inlet or air outlet can be individually blocked, so that the fan structure is in the suction or blowing mode.

[0004] Among them, the design of the wind shield structure is relatively complicated, and it is easy to have air leakage due to poor shielding; and controlling the switching state of the wind shield structure requires the additional installation of a control motor, which not only takes up space but also increases the total weight of the fan structure. Summary of the invention

[0005] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a cascade fan structure for a seat blowing and suction system.

[0006] The present invention provides a cascade fan structure for a seat blowing and suction system, comprising: A first fan assembly, wherein the first fan assembly has a first air outlet and a first space inside; the first space is connected to the first air outlet; A second fan assembly, wherein the second fan assembly has a second air outlet and a second space inside; the second space is connected to the second air outlet; The first fan assembly and the second fan assembly are connected to each other, and the first space is communicated with the second space; When the first fan assembly is actively working and the second fan assembly is not working, the second air outlet is used as an air suction outlet and the first air outlet is used as an air blowing outlet; the flow direction of the gas passes through the second air outlet, the second space, the first space and the first air outlet in sequence; When the second fan assembly is actively working and the first fan assembly is not working, the first air outlet serves as an air suction outlet and the second air outlet serves as an air blowing outlet; the flow direction of the gas passes through the first air outlet, the first space, the second space and the second air outlet in sequence.

[0007] According to the technical solution provided by the present invention, the first fan assembly includes a first shell and a second shell, and the first space is formed between the first shell and the second shell; The second fan assembly comprises a third housing and a fourth housing, and the second space is formed between the third housing and the fourth housing; The second shell and the third shell are connected via a connecting structure; A first connecting hole is formed on a side of the second shell close to the third shell and a side of the third shell close to the second shell. The connecting structure connects the two first connecting holes to connect the first space with the second space.

[0008] According to the technical solution provided by the present invention, the connection structure includes a connecting pipe, and the connecting pipe connects the first space and the second space.

[0009] According to the technical solution provided by the present invention, the first fan assembly includes a fifth housing, and the second fan assembly includes a seventh housing; A sixth shell is installed between the fifth shell and the seventh shell; the first space is formed between the sixth shell and the fifth shell; the second space is formed between the sixth shell and the seventh shell; a second connecting hole is opened on the sixth shell for connecting the first space with the second space.

[0010] According to the technical solution provided by the present invention, connecting parts are installed between the sixth shell and the first fan assembly and the second fan assembly for fixing the first fan assembly, the second fan assembly and the sixth shell.

[0011] According to the technical solution provided by the present invention, the sixth shell has a raised portion; the diameter of the fifth shell is greater than the diameter of the seventh shell, and the diameter of the raised portion is greater than or equal to the diameter of the fifth shell; a connecting space is formed between the raised portion and the fifth shell for connecting to the wind guide layer.

[0012] According to the technical solution provided by the present invention, the connecting structure includes a sealing ring and a fixing structure, the first fan assembly and the second fan assembly are fixed to each other through the fixing structure, and the gap between the first fan assembly and the second fan assembly is sealed by the sealing ring.

[0013] According to the technical solution provided by the present invention, the first fan assembly includes a first impeller, and the second fan assembly includes a second impeller; the first impeller and the second impeller both include blades; the size of the first impeller and the second impeller, and at least one of the length, thickness and inclination angle of the blades on the first impeller and the second impeller are different.

[0014] According to the technical solution provided by the present invention, the first fan assembly and the second fan assembly share a circuit board.

[0015] According to the technical solution provided by the present invention, the stator of the first fan assembly and the stator of the second fan assembly are arranged in a staggered manner.

[0016] The beneficial effects of the present invention are: Two fan assemblies are integrated and installed together, wherein each of the two fan assemblies has an air outlet and an internal space; the internal spaces of the two fan assemblies are connected. When one of the fan assemblies is working, the air outlet of this fan assembly serves as an air outlet, and the air outlet of the other fan assembly serves as an air suction outlet; the two fan assemblies are controlled to work separately to achieve the effect of switching the air suction and blowing modes of one air outlet. The above method has a simple internal structure design and is not prone to air leakage; at the same time, no additional switching motor is required, which reduces the space occupied by the motor installation and reduces the total weight of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings: Figure 1 is a schematic diagram of a fan structure in one implementation manner; Figure 2 A cross-sectional view of a first fan assembly in operation according to an embodiment; Figure 3 A cross-sectional view of a second fan assembly in operation according to an embodiment; Figure 4 A schematic diagram of a fan structure in another embodiment; Figure 5 A cross-sectional view of another embodiment of the first fan assembly when in operation; Figure 6 A cross-sectional view of another embodiment of the second fan assembly when in operation; Figure 7 is a schematic structural diagram of a third shell and a fourth shell in another embodiment; Figure 8 A cross-sectional view showing the air guide housing being installed and the first fan assembly being in operation; Fig. 9 It is a cross-sectional view when the air guide housing is installed and the second fan assembly is working; Fig.10 is a schematic diagram of another embodiment in which the second fan assembly is an axial fan; Fig.11 is a cross-sectional view of the second fan assembly when the first fan assembly is an axial fan in operation; Fig.12 is a cross-sectional view of the second fan assembly when the second fan assembly is an axial fan and is in operation; Fig.13It is a cross-sectional view of the first fan assembly when the first fan assembly of the air guide layer is working; Fig.14 It is a cross-sectional view of the first fan assembly when the second fan assembly of the air guide layer is working; Fig.15 is a schematic diagram of a first fan assembly being a centrifugal fan and a second fan assembly being an axial fan; Fig.16 for Fig.15 A schematic diagram of the first fan assembly in operation; Fig.17 for Fig.15 A schematic diagram of the second fan assembly in operation; Fig.18 An exploded view of a cascade fan structure for a seat blowing and suction system; Fig.19 An exploded view of the first fan assembly and the second fan assembly housing; Fig. 20 It is a schematic diagram of a structure with a connecting part installed; Fig.21 is a cross-sectional view of the first fan assembly when the connecting portion is installed and the first fan assembly is in operation; Fig. 22 is a cross-sectional view of the second fan assembly when the connecting portion is installed and the second fan assembly is in operation; Fig.23 A cross-sectional view of another embodiment in which the sixth housing is installed and the first fan assembly is in operation; Fig.24 A cross-sectional view of another embodiment in which a sixth housing is installed and a second fan assembly is in operation; Fig.25 is a front view of the fan when the diameter of the protrusion is equal to that of the fifth housing; Fig.26 is a cross-sectional view of the fan when the diameter of the protrusion is equal to that of the fifth housing; Fig. 27 is a schematic diagram of the fan being installed on the air guide layer when the diameter of the protrusion is equal to that of the fifth shell; Among them: 1. first fan assembly; 2. second fan assembly; 3. first air outlet; 4. second air outlet; 5. connecting pipe; 6. sixth shell; 7. connecting piece; 8. rotating shaft; 9. first shell; 10. second shell; 11. third shell; 12. fourth shell; 13. fifth shell; 14. seventh shell; 15. wind guide layer; 16. fan blades; 17. partition plate; 18. connecting part; 19. second through hole; 20. protrusion. DETAILED DESCRIPTION

[0018] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It should also be noted that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0019] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0020] The shaded parts in all the drawings of the present invention are in working state.

[0021] refer to Figure 1 and 18 The present invention provides a cascade fan structure for a seat blowing and suction system, comprising: A first fan assembly 1, wherein the first fan assembly 1 has a first air outlet 3 and has a first space inside; the first space is connected to the first air outlet 3; A second fan assembly 2, wherein the second fan assembly 2 has a second air outlet 4 and has a second space inside; the second space is connected to the second air outlet 4; The first fan assembly 1 and the second fan assembly 2 are connected to each other, and the first space is communicated with the second space.

[0022] In this embodiment, the fan assembly includes: an external shell, a rotating shaft 8 (serving as a stator) fixedly installed in the internal space of the shell, fan blades 16 (serving as a rotor) installed in the internal space of the shell, and a circuit board electrically connected to the stator via PIN pins.

[0023] In some embodiments, the first fan assembly 1 is mounted on the air guide layer 15 of the seat, and the first air outlet 3 is in communication with the air guide layer 15 of the seat; refer to Figure 2 When the first fan assembly 1 is actively working and the second fan assembly 2 is not working, the second air outlet 4 serves as an air suction outlet and the first air outlet 3 serves as an air blowing outlet; the flow direction of the gas passes through the second air outlet 4, the second space, the first space and the first air outlet 3 in sequence; the fan of the second fan assembly 2 will rotate passively; the function of blowing air to the seat air guide layer 15 is realized, thereby achieving blowing air on the seat seat.

[0024] refer to Figure 3When the second fan assembly 2 is actively working and the first fan assembly 1 is not working, the first air outlet 3 is used as an air suction outlet and the second air outlet 4 is used as an air blowing outlet; the flow direction of the gas passes through the first air outlet 3, the first space, the second space and the second air outlet 4 in sequence; the fan of the first fan assembly 1 will rotate passively; the function of sucking air from the seat air guide layer 15 is realized, thereby realizing air suction on the seat seat.

[0025] During use, only one fan assembly is controlled to work at the same time, so as to achieve the effect of controlling the first air outlet 3 to suck and blow respectively, and switching the fan structure suction and blowing modes. The above method has a simple internal structure design and is not prone to air leakage; at the same time, no additional motor is required, which reduces the space occupied by the motor installation and reduces the total weight of the structure.

[0026] In some embodiments, reference Figure 7 The first shell 9 and the second shell 10 of the first fan assembly 1 form an air guide shell; the air guide shell is installed inside the air guide layer 15 of the seat, and an air guide port is opened on the air guide shell, which is connected to the air guide layer 15 of the seat; the gas flows between the air guide layer 15 and the first space of the first fan assembly through the air guide port of the air guide shell; since the cross-section of the gas flow is reduced, the flow rate of the gas can be increased.

[0027] Reference for gas flow in different working modes of the air guide housing Figure 8-9 , the arrow direction is the gas flow direction. Figure 8 The first fan assembly 1 is working; Fig. 9 The second fan assembly 2 is working.

[0028] When the first fan assembly 1 is installed on the air guide layer 15, the schematic diagram of the two working states of the two fan assemblies is shown in FIG. Figure 13-14 , the arrow indicates the direction of gas flow. When the first fan assembly 1 is working, it realizes the blowing function to the air guide layer 15, and when the second fan assembly is working, it realizes the suction function to the air guide layer. Fig.13 The first fan assembly 1 is working; Fig.14 The second fan assembly 2 is working.

[0029] Specifically, the housings of the first fan assembly 1 and the second fan assembly 2 may be a detachable structure or an integrated structure.

[0030] Among them, reference Fig.19 , the detachable structure is specifically as follows: Furthermore, the first fan assembly 1 includes a first shell 9 and a second shell 10, and the first space is formed between the first shell 9 and the second shell 10; The second fan assembly 2 includes a third housing 11 and a fourth housing 12, and the second space is formed between the third housing 11 and the fourth housing 12; The second shell 10 and the third shell 11 are connected via a connection structure, and the first space and the second space are communicated via the connection structure.

[0031] Specifically, Figure 2-3 In the figure, the arrow direction is the gas flow direction. Figure 2 The first fan assembly 1 is working; Figure 3 The second fan assembly 2 is working.

[0032] Wherein, the connection structure includes a connecting pipe 5, and the connecting pipe 5 connects the first space and the second space.

[0033] Specifically, first connecting holes are provided on the side of the second shell 10 close to the third shell 11 and on the side of the third shell 11 close to the second shell 10 . The connecting structure includes a connecting pipe 5 connecting the two first connecting holes for connecting the first space with the second space.

[0034] In some embodiments, the connecting pipe 5 is a hose that connects the first space and the second space so that gas can flow directly between the two fans.

[0035] Among them, the integrated structure is specifically: The first fan assembly 1 includes a fifth housing 13, and the second fan assembly 2 includes a seventh housing 14; The sixth housing 6 is installed between the fifth housing 13 and the seventh housing 14; the first space is formed between the sixth housing 6 and the fifth housing 13; the second space is formed between the sixth housing 6 and the seventh housing 14; the sixth housing 6 is provided with a second connecting hole for connecting the first space with the second space. After the fifth housing 13, the sixth housing 6 and the seventh housing 14 are connected to each other, the housings of the first fan assembly 1 and the second fan assembly 2 form an integrated structure, and the first space is directly connected with the second space.

[0036] Further, refer to Figure 25-27 The sixth shell 6 has a protrusion 20; the diameter of the fifth shell 13 is greater than the diameter of the seventh shell 14, and the diameter of the protrusion 20 is greater than or equal to the diameter of the fifth shell 13; a connecting space is formed between the protrusion 20 and the fifth shell 13 for connecting with the wind guide layer 15.

[0037] The wind guide layer 15 includes a wind bag. In this case, the protrusion 20 and the fifth shell 13 both have a longer portion, which can be connected to the pressure-bearing wind guide structure inside the wind bag, making the connection between the fan and the wind guide layer 15 more stable, so as to reduce the possibility of falling off due to external force or long-term use.

[0038] Furthermore, connecting members 7 are installed between the sixth housing 6 and the first fan assembly 1 and the second fan assembly 2 for fixedly connecting the first fan assembly 1 , the second fan assembly 2 and the sixth housing 6 .

[0039] The gas flow direction is referenced Figure 5-6 The working mode of the two fan assemblies is the same as that of the previous embodiment. Figure 5 The first fan assembly 1 is working; Figure 6 The second fan assembly 2 is working.

[0040] In some embodiments, the shells of the two fan assemblies are connected via a sixth shell 6. This connection method can provide a larger connecting cross-section between the first space and the second space, thereby facilitating the increase of gas flow and the improvement of ventilation effect.

[0041] In some embodiments, when the shells of the two fans are connected, they may collide with each other due to vibration and make noise. In this embodiment, a connecting member 7 is used to respectively connect the shells of the first fan assembly 1 and the second fan assembly 2 to achieve the effect of buffering vibration and reducing noise.

[0042] In some embodiments, reference Figure 23-24 The position of the sixth housing 6 facing the first fan assembly and the second fan assembly is not connected to the first space and the second space. The second through hole 19 is located near the edge of the sixth housing 6, and the first space and the second space are connected through the second through hole 19.

[0043] The side walls of the fifth shell 13 and the seventh shell 14 are not connected to the outside, so the gas can only enter the second space from the first space or enter the first space from the second space through the second through hole 19.

[0044] Furthermore, the connection structure includes a sealing ring and a fixing structure, and the first fan assembly 1 and the second fan assembly 2 are fixed to each other through the fixing structure; the gap between the first fan assembly 1 and the second fan assembly 2 is sealed by the sealing ring.

[0045] Specifically, the fixing structure can be a clamping structure provided on the first fan assembly 1 and the second fan assembly 2, or it can be a hard or soft fixing nail; the first fan assembly 1 and the second fan assembly 2 are clamped to each other or fixed to each other by connecting rivets, and a sealing ring is provided between the shells of the two fan assemblies abutting each other, which can effectively avoid air leakage from the connection between the shells of the two fan assemblies.

[0046] Furthermore, the first fan assembly 1 includes a first impeller, and the second fan assembly 2 includes a second impeller; the first impeller and the second impeller both include blades 16; the size of the first impeller and the second impeller, and at least one of the length, thickness and inclination angle of the blades 16 on the first impeller and the second impeller are different.

[0047] Specifically, since the ventilation effects required for suction and blowing are different, it is difficult to fully adapt by simply changing the fan speed. Therefore, in this embodiment, the size of the fan blades 16 is improved to make the blades 16 of the two fans different in size, and the fan speeds are controlled to achieve a variety of different ventilation effects.

[0048] Furthermore, the first fan assembly 1 and the second fan assembly 2 are arranged toward each other, arranged back to back with each other, or arranged in the same direction.

[0049] Since the fan assembly controls the rotation of the fan blades 16 using a corresponding circuit, and the circuit is generally arranged on a circuit board, the fan assembly generally also includes a circuit board. In this embodiment, since there are two sets of fan assemblies, there should generally be two circuit boards, and the circuit board itself has thickness.

[0050] When the two fan assemblies are arranged back to back or in the same direction, the two circuit boards are stacked on top of each other, which will increase the thickness of the overall structure.

[0051] In this embodiment, when the first fan assembly 1 and the second fan assembly 2 are arranged facing each other, they share a circuit board, so that only one circuit board can be used to control the two fan assemblies, reducing the thickness of the entire structure.

[0052] Furthermore, the stator of the first fan assembly 1 and the stator of the second fan assembly 2 are arranged in a staggered manner.

[0053] Since the wires on the circuit board need to be connected to the stator of the fan assembly, when the stators of the two fan assemblies are coaxial, the difficulty of circuit layout on the circuit board will increase; in this embodiment, the stators of the two fan assemblies are staggered with each other so that the wires on the circuit board can be staggered with each other, reducing the difficulty of circuit layout.

[0054] Specifically, the first fan assembly 1 uses a centrifugal fan, and the first air port 3 is opened at a lateral position of the first fan assembly 1 for allowing the centrifugal fan in the first fan assembly 1 to blow out gas laterally through the first air port 3 .

[0055] There are two situations for selecting the fan in the second fan assembly 2: The first case: the second air port 4 is opened at a lateral position of the second fan assembly 2; the second fan assembly 2 includes a centrifugal fan; the centrifugal fan is used to blow out gas through the second air port 4 in a lateral direction.

[0056] This situation is suitable for scenes where the space perpendicular to the direction of the air guide layer 15 is narrow or there are passengers. Side blowing can prevent surrounding objects from blocking the air outlet.

[0057] The second case: reference Fig.10 The second air port 4 is opened at the axial position of the second fan assembly 2; the second fan assembly 2 includes an axial fan; the axial fan is used to blow out gas through the second air port 4 along the axial direction.

[0058] This situation is suitable for scenes where the space along the extension direction of the air guide layer 15 is narrow or blocked by objects. Suctioning air along the axial direction can prevent lateral objects from being sucked into the fan assembly by negative pressure, causing malfunctions.

[0059] In this case, the flow direction of the gas in different fan working modes is referenced Figure 11-12 The direction of the arrow. Fig.11 The first fan assembly 1 is working; Fig.12 The second fan assembly 2 is working.

[0060] refer to Figure 15-17 The first fan assembly is equipped with a centrifugal fan and the second fan assembly is equipped with an axial fan, and the direction of the arrow indicates the direction of gas movement.

[0061] In some embodiments, reference Fig. 20 The first housing 9, the second housing 10 of the first fan assembly and the third housing 11 and the fourth housing 12 of the second fan assembly are connected with a connecting portion 18. The connecting portion 18 is a hard housing or an elastic connecting member. The elastic connecting member can be a rubber tube, a rubber interface or a bellows. The connecting portion 18 connects the first space with the second space.

[0062] Figure 20-22 In the figure, the first fan assembly and the second fan assembly are both equipped with centrifugal fans; the connecting portion 18 is a hard shell, the interior of which is a hollow structure, and the internal space is divided into two connected parts by a partition plate 17, and the partition plate 17 is fixedly connected to the second shell 10 and the third shell 11 at the same time, so that the two parts of the space in the connecting portion 18 are connected to the first space and the second space respectively.

[0063] When the centrifugal fan is installed, the first housing 9, the second housing 10, the third housing 11 and the remaining parts of the fourth housing 12 prevent the internal spaces of the first fan assembly and the second fan assembly from being connected to the outside. The first space is connected to the second space only through the connection 18; the blown gas enters the other space only through the connection 18.

[0064] refer to Fig.21 When the first fan assembly is working, the gas enters the second space from the first space through the connecting portion 18, thus realizing the air suction function. Fig. 22 When the second fan assembly is working, the gas enters the first space from the second space through the connecting portion 18 to achieve the blowing function. Figure 21-22 In the figure, arrows indicate the direction of gas movement.

[0065] The above description is only a preferred embodiment of the present invention and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present invention is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in the present invention (but not limited to) to form a technical solution.

Claims

1. A cascade fan structure for a seat blowing and suction system, characterized in that: include: A first fan assembly (1), wherein the first fan assembly (1) has a first air outlet (3) and a first space inside; The first space is in communication with the first air outlet (3); A second fan assembly (2), the second fan assembly (2) having a second air outlet (4) and a second space inside; the second space is in communication with the second air outlet (4); The first fan assembly (1) and the second fan assembly (2) are connected to each other, and the first space is in communication with the second space; When the first fan assembly (1) is actively working and the second fan assembly (2) is not working, the second air outlet (4) serves as an air suction outlet and the first air outlet (3) serves as an air blowing outlet; the flow direction of the gas passes through the second air outlet (4), the second space, the first space and the first air outlet (3) in sequence; When the second fan assembly (2) is actively working and the first fan assembly (1) is not working, the first air outlet (3) serves as an air suction outlet and the second air outlet (4) serves as an air blowing outlet; the flow direction of the gas passes through the first air outlet (3), the first space, the second space and the second air outlet (4) in sequence.

2. A cascade fan structure for a seat blowing and suction system according to claim 1, characterized in that: The first fan assembly (1) comprises a first shell (9) and a second shell (10), wherein the first space is formed between the first shell (9) and the second shell (10); The second fan assembly (2) comprises a third shell (11) and a fourth shell (12), wherein the second space is formed between the third shell (11) and the fourth shell (12); The second shell (10) and the third shell (11) are connected via a connecting structure; A first connecting hole is provided on a side of the second shell (10) close to the third shell (11) and a side of the third shell (11) close to the second shell (10), and the connecting structure connects the two first connecting holes to connect the first space with the second space.

3. The cascade fan structure for a seat blowing and suction system according to claim 2, characterized in that: The connection structure comprises a connecting pipe (5), wherein the connecting pipe (5) connects the first space with the second space.

4. The cascade fan structure for a seat blowing and suction system according to claim 1, characterized in that: The first fan assembly (1) comprises a fifth housing (13), and the second fan assembly (2) comprises a seventh housing (14); A sixth shell (6) is installed between the fifth shell (13) and the seventh shell (14); the first space is formed between the sixth shell (6) and the fifth shell (13); the second space is formed between the sixth shell (6) and the seventh shell (14); and a second connecting hole is provided on the sixth shell (6) for connecting the first space with the second space.

5. The cascade fan structure for a seat blowing and suction system according to claim 4, characterized in that: Connecting pieces (7) are installed between the sixth housing (6) and the first fan assembly (1) and the second fan assembly (2), and are used to fix the first fan assembly (1), the second fan assembly (2) and the sixth housing (6).

6. The cascade fan structure for a seat blowing and suction system according to claim 5, characterized in that: The sixth shell (6) has a protruding portion (20); the diameter of the fifth shell (13) is greater than the diameter of the seventh shell (14), and the diameter of the protruding portion (20) is greater than or equal to the diameter of the fifth shell (13); a connecting space is formed between the protruding portion (20) and the fifth shell (13) for connecting to the air guide layer (15).

7. The cascade fan structure for a seat blowing and suction system according to claim 2, characterized in that: The connection structure comprises a sealing ring and a fixing structure, wherein the first fan assembly (1) and the second fan assembly (2) are fixed to each other via the fixing structure, and the sealing ring is used to seal a gap between the first fan assembly (1) and the second fan assembly (2).

8. The cascade fan structure for a seat blowing and suction system according to claim 1, characterized in that: The first fan assembly (1) comprises a first impeller, and the second fan assembly (2) comprises a second impeller; the first impeller and the second impeller both comprise blades (16); the first impeller and the second impeller have different sizes, and at least one of the length, thickness and inclination angle of the blades (16) on the first impeller and the second impeller.

9. The cascade fan structure for a seat blowing and suction system according to claim 1, characterized in that: The first fan assembly (1) and the second fan assembly (2) share a circuit board.

10. The stacked fan structure for a seat blowing and suction system according to claim 9, characterized in that: The stator of the first fan assembly (1) and the stator of the second fan assembly (2) are arranged in a staggered manner.

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