Volute type centrifugal fan
By combining foil air bearings and mechanical bearings in a centrifugal fan, the problem of axial tension on the bearings by the impeller is solved, the service life of the bearings and the reliability of the motor are improved, and the effect of simplified structure and long service life is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-14
- Publication Date
- 2026-03-03
AI Technical Summary
In existing centrifugal fans, the axial tension of the impeller on the bearing is large, resulting in a short bearing life and generally low reliability. Especially under conditions of large diameter or high outlet pressure, the control current of magnetic levitation and air suspension bearings increases or the air gap becomes smaller, affecting the safety and lifespan of the bearings.
The design employs a combination of foil air bearings and mechanical bearings. The foil air bearings bear the axial tensile force, while the mechanical bearings are angular contact bearings. The axial force is balanced by an axial thrust assembly, which reduces the axial displacement and heat generation of the mechanical bearings.
It effectively bears axial tensile force, improves the service life of mechanical bearings, reduces the failure rate, enhances the structural simplicity and reliability of the motor, and extends the service life of the motor.
Smart Images
Figure CN223964617U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of aerodynamic equipment technology, and in particular to a volute centrifugal fan. Background Technology
[0002] Blowers, as a type of ventilation machinery, are widely used in various industries, especially in the fields of petroleum, chemical, metallurgy, aviation, aerospace, and environmental protection.
[0003] There are various types of blowers, with centrifugal blowers being a common one. When a centrifugal blower is operating, the high-speed rotation of the impeller generates pressure at the impeller outlet. This pressure acts on all surfaces of the impeller, and the resulting force always points towards the impeller inlet, pulling the entire rotor towards the air inlet. This axial force ultimately acts on the bearings (including various types of bearings such as mechanical bearings, magnetic bearings, air bearings, and oil bearings). If the impeller diameter is large or the outlet pressure is high, the axial force on the rotor will be very large, which is detrimental to the long-term safe operation of the bearings, increasing the failure rate and reducing their service life. This is especially true for magnetic and air bearings; when the rotor axial force is too large, the control current of the magnetic bearing must increase significantly, and the air gap of the air bearing must decrease significantly, both affecting their safety and lifespan. Installing a balance disc or increasing the number of bearings requires increasing the axial length of the rotor, increasing the design complexity of the equipment.
[0004] Therefore, it is indeed necessary to improve existing technologies to address their shortcomings. Utility Model Content
[0005] The purpose of this application is to provide a volute centrifugal fan to solve the problems of large axial tension of the impeller on the bearing, short bearing service life, and general reliability in the prior art.
[0006] The embodiments of this application can be implemented through the following technical solutions:
[0007] A volute centrifugal fan includes a worm gear and a motor. The worm gear and the motor are coaxially connected. Both ends of the motor shaft are connected to bearing seats of the motor end cover via mechanical bearings. At least one end of the motor shaft is also connected to a foil air bearing. The foil air bearing is located at the front end of the mechanical bearing adjacent to the worm gear or at the rear end of the mechanical bearing away from the worm gear.
[0008] Furthermore, when the foil air bearing is disposed at the front end of the mechanical bearing adjacent to the worm gear, the worm gear and the motor are coaxially connected through an axial thrust assembly. The axial thrust assembly includes a sealing disc and a foil air bearing, and the sealing disc is connected to the side of the foil air bearing facing the worm gear.
[0009] Furthermore, the worm gear includes a volute, an impeller shaft, and an impeller. The rear end of the volute is connected to the front end cover of the motor. The impeller is connected to the motor shaft via the impeller shaft. The sealing disc is connected between the impeller and the front end cover and seals the gap between the outer edge of the rear end of the impeller and the front end cover.
[0010] Furthermore, when the foil air bearing is located at the rear end of the mechanical bearing away from the worm gear, the motor shaft extends to the sealing disc passing through the rear end of the foil air bearing. The sealing disc and the foil air bearing, which are coaxially connected, together constitute an axial thrust assembly. The axial thrust assembly is located at the rear end of the rear end cover of the motor. The sealing disc and the rear end cover cooperate to form a relatively sealed space.
[0011] Furthermore, the foil air bearing includes foil and a thrust plate. The thrust plate is fixedly connected to the motor shaft. There are two foils. The two foils are evenly distributed at both ends of the thrust plate along its circumference. Each foil has at least two fixing points along its circumference that are fixedly connected to the motor end cover or sealing plate. There is a gap between two adjacent fixing points on the same side for free gas flow.
[0012] Furthermore, the bearings connected to both ends of the motor shaft are a first angular contact bearing and a second angular contact bearing, respectively;
[0013] Wave springs are provided between the inner and outer rings at both ends of the first angular contact bearing and the second angular contact bearing.
[0014] Furthermore, the first angular contact bearing is disposed on the inner side of the rear end of the front end cover, the second angular contact bearing is disposed in the bearing seat at the rear end cover, the end of the motor shaft extends rearward to pass through the rear end cover and connects with the fan blade disposed on the outer side of the rear end cover, and a fan cover is sleeved on the outside of the rear end cover.
[0015] Furthermore, the motor is also equipped with an oil seal, which is connected to the outer side of the motor shaft in a rotatable fit.
[0016] Furthermore, an O-ring is also provided inside the motor, and the O-ring is connected between the connection gaps of two adjacent connectors.
[0017] The embodiments of this application provide a volute-type centrifugal fan that has at least the following beneficial effects:
[0018] This application adopts a combination of foil air bearings and mechanical bearings. The foil air bearings fully bear the axial tension applied to the mechanical bearing on the motor shaft when the worm gear is running, avoiding the mechanical bearing from overheating and temperature rise due to axial force. On this basis, the mechanical bearing inside the motor is set as an angular contact bearing with better load-bearing capacity and rigidity, which greatly improves the service life of the motor. It has the advantages of simple structure, long service life and strong practicality. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the overall structure of a volute centrifugal fan in Embodiment 1.
[0020] Figure 2 For along Figure 1 The cross-sectional structure diagram shown by the AA line marked in the middle;
[0021] Figure 3 for Figure 2 A magnified view of part B in the middle section;
[0022] Figure 4 As in Example 2 Figure 1 The cross-sectional structure diagram shown by the AA line marked in the middle.
[0023] Numbers in the diagram
[0024] 1-Wheel drive; 11-Vortex housing; 12-Impeller shaft; 13-Impeller; 2-Motor; 20-Motor housing; 21-Motor shaft; 22-Rotor; 23-Stator; 24-First angular contact bearing; 25-Second angular contact bearing; 26-Fan blade; 27-Fan cover; 28-Rear end cover; 29-Front end cover; 3-Axial thrust assembly; 31-Sealing disc; 32-Foil air bearing; 321-Foil; 322-Thrust disc; 4-Oil seal; 5-O-ring. Detailed Implementation
[0025] The present application will now be further described based on preferred embodiments and with reference to the accompanying drawings.
[0026] In addition, for ease of understanding, various components on the drawings have been enlarged (thickened) or reduced (thinned), but this is not intended to limit the scope of protection of this application.
[0027] Singular forms of words also include plural meanings, and vice versa.
[0028] In the description of the embodiments of this application, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, in the description of this application, in order to distinguish different units, the terms "first," "second," etc. are used in this specification, but these are not limited by the manufacturing order, nor should they be construed as indicating or implying relative importance. Their names may differ in the detailed description and claims of this application.
[0029] The vocabulary used in this specification is for illustrative purposes and is not intended to limit the scope of this application. It should also be noted that, unless otherwise expressly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection via an intermediate medium; or they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of these terms in this application.
[0030] Example 1
[0031] Figure 1 This is a schematic diagram of the overall structure of a volute-type centrifugal fan according to this application. Figure 2 For along Figure 1 The cross-sectional structure diagram shown by the AA line marked in the middle, as follows: Figure 1 , Figure 2 As shown, a volute centrifugal fan includes a worm gear 1 and a motor 2. The worm gear 1 and the motor 2 are coaxially connected. The two ends of the motor shaft 21 of the motor 2 are respectively connected to the bearing seats of the motor end cover through mechanical bearings. At least one end of the motor shaft 21 is also connected to a foil air bearing 32. The foil air bearing 32 is disposed at the front end of the mechanical bearing adjacent to the worm gear 1. By adopting a design that combines the foil air bearing 32 and the mechanical bearing, and by placing the foil air bearing 32 at the front end of the mechanical bearing adjacent to the worm gear 1, the axial tensile force generated when the worm gear 1 is running can be quickly responded to and balanced, thus bearing the axial tensile force on the mechanical bearing, improving the service life of the angular mechanical bearing, and ensuring the stable operation of the motor.
[0032] In some preferred embodiments, the motor 2 includes a motor shaft 21, a rotor 22, and a stator 23. The rotor 22 is connected to the middle of the motor shaft 21, and the stator 23 is fixed to the inner wall of the motor housing 20 on the outside of the rotor 22. The above is a conventional configuration in the art. Since the axial thrust assembly 3 bears the axial tension of the angular contact bearing during the high-speed rotation of the impeller, it is not necessary to add multiple sets of mechanical bearings to balance the axial load in this application, which greatly reduces the cost.
[0033] In some preferred embodiments, the mechanical bearings at both ends of the motor shaft 21 are a first angular contact bearing 24 and a second angular contact bearing 25, respectively. This is because angular contact bearings can withstand radial loads and a certain amount of axial loads, and can also better disperse axial forces and extend service life.
[0034] In some preferred embodiments, the worm gear 1 includes a volute 11, an impeller shaft 12, and an impeller 13. The rear end of the volute 11 is connected to the front end cover 29 of the motor 2, and the impeller 13 is connected to the motor shaft 21 through the impeller shaft 12. When the foil air bearing 32 is located at the rear end of the mechanical bearing away from the worm gear 1, a sealing disc 31 is also provided at the front end of the foil air bearing 32. That is, the sealing disc 31 is connected to the side of the foil air bearing 32 facing the worm gear 1. The sealing disc 31 and the foil air bearing 32, which are coaxially connected, together constitute the axial thrust assembly 3.
[0035] In some preferred embodiments, the sealing disc 31 is connected between the impeller 13 and the front end cover 29, and seals the gap between the outer edge of the rear end of the impeller 13 and the front end cover 29, so that a relatively sealed space is formed between the front end cover 29 and the sealing disc 31. This provides a relatively sealed space for the foil air bearing 32, ensuring that the gas film inside the foil air bearing 32 can remain stable and enhancing the structural stability of the foil air bearing 32. The foil air bearing 32 maintains stable gas dynamic pressure and support force by adaptively adjusting the size and shape of the gap gas film, thereby reducing the axial tension borne by the bearing of the motor 2 during the high-speed rotation of the impeller.
[0036] Specifically, Figure 3 for Figure 2 A magnified view of part B in the middle, as shown below. Figure 3As shown, the foil air bearing 32 includes foil 321 and thrust plate 322. The thrust plate 322 is fixedly connected to the motor shaft 21. There are two foils 321, which are evenly distributed at both ends of the thrust plate 322 along its circumference. Each foil 321 has at least two fixing points along its circumference that are fixedly connected to the front end cover 29 or the sealing plate 31. There is a gap between two adjacent fixing points on the same side for free gas flow to form a continuous air film. When the motor shaft 21 drives the impeller shaft 102 to rotate at high speed, air is drawn into the gap between the foil 321 and the thrust plate 322 by the impeller 13, forming a dynamic pressure effect. The compressed air film will exert a reverse force on the thrust plate 322 to reduce the axial tension borne by the motor shaft 21 during rotation.
[0037] In some preferred embodiments, since the axial thrust assembly 3 greatly reduces the axial tension of the motor shaft 21 during rotation, the range of motion of the bearing of the motor 2 along the axial direction of the motor shaft 21 is increased. In order to avoid unnecessary damage to the bearing due to unbalanced force during axial displacement, wave springs are provided between the inner and outer rings at both ends of the first angular contact bearing 24 and the second angular contact bearing 25.
[0038] In some preferred embodiments, the first angular contact bearing 24 is disposed on the inner rear end of the front end cover 29, the rear end of the motor housing 20 is connected to the rear end cover 28, the second angular contact bearing 25 is disposed in the bearing seat at the rear end cover 28, the end of the motor shaft 21 extends rearward to pass through the rear end cover 28 and is connected to the fan blade 26 disposed on the outer side of the rear end cover 28, and a fan cover 27 is fitted on the outside of the rear end cover 28 for dust protection of the internal structure of the motor 2.
[0039] In some preferred embodiments, since the internal temperature of the motor gradually decreases after it stops rotating, moisture in the air will enter the motor and condense into water droplets during the temperature drop process. Over time, this will cause rust and damage inside the motor, greatly reducing the life of the motor. Therefore, the applicant has also optimized the sealing structure of the motor.
[0040] like Figure 3 As shown, the motor 2 is also provided with an oil seal 4 and an O-ring 5. The oil seal 4 is connected to the outer side of the motor shaft 21 in a rotating fit connection gap and is used as a dynamic seal. The O-ring 5 is connected between the connection gaps of two adjacent connecting parts and is used as a static seal.
[0041] Example 2
[0042] This embodiment is similar in overall structure to Embodiment 1, except for the placement of the foil air bearing 32. Figure 4 As shown, the foil air bearing 32 is located at the rear end of the mechanical bearing away from the worm gear 1. The foil air bearing 32 is used to provide additional axial support under specific working conditions to cope with the large axial tension generated when the worm gear 1 is running, reduce the axial tension on the angular contact bearing, and thus extend the service life of the motor.
[0043] In some preferred embodiments, along the extension direction of the motor shaft 21, the motor shaft 21 extends to a sealing disc 31 passing through the rear end of the foil air bearing 32. That is, the sealing disc 31 is connected to the side of the foil air bearing 32 facing away from the worm gear 1. The sealing disc 31 and the foil air bearing 32, which are coaxially connected, together constitute an axial thrust assembly 3. The axial thrust assembly 3 is disposed at the rear end of the rear end cover 28. The sealing disc 31 and the rear end cover 28 cooperate to form a relatively sealed space, ensuring that the air film inside the foil air bearing 32 can remain stable and enhancing the structural stability of the foil air bearing 32. The foil air bearing 32 maintains stable gas dynamic pressure and support force by adaptively adjusting the size and shape of the gap air film, thereby reducing the axial tension borne by the bearing of the motor 2 during the high-speed rotation of the impeller.
[0044] The specific embodiments of this application have been described in detail above. For those skilled in the art, several improvements and modifications can be made to this application without departing from the principle of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.
Claims
1. A volute centrifugal fan, comprising a worm gear (1) and a motor (2), characterized in that: The worm gear (1) and the motor (2) are coaxially connected. The two ends of the motor shaft (21) of the motor (2) are respectively connected to the bearing seats of the motor end cover through mechanical bearings. At least one end of the motor shaft (21) is also connected to a foil air bearing (32). The foil air bearing (32) is located at the front end of the mechanical bearing adjacent to the worm gear (1) or at the rear end of the mechanical bearing away from the worm gear (1).
2. The volute centrifugal fan according to claim 1, characterized in that: When the foil air bearing (32) is located at the front end of the mechanical bearing adjacent to the worm gear (1), the worm gear (1) and the motor (2) are coaxially connected by an axial thrust assembly (3). The axial thrust assembly includes a sealing disc (31) and a foil air bearing (32). The sealing disc (31) is connected to the side of the foil air bearing (32) facing the worm gear (1).
3. The volute centrifugal fan according to claim 2, characterized in that: The worm gear (1) includes a volute (11), an impeller shaft (12), and an impeller (13). The rear end of the volute (11) is connected to the front end cover (29) of the motor (2). The impeller (13) is connected to the motor shaft (21) through the impeller shaft (12). The sealing disc (31) is connected between the impeller (13) and the front end cover (29) and seals the gap between the outer edge of the rear end of the impeller (13) and the front end cover (29).
4. The volute centrifugal fan according to claim 1, characterized in that: When the foil air bearing (32) is located at the rear end of the mechanical bearing away from the worm gear (1), the motor shaft (21) extends to the sealing disc (31) passing through the rear end of the foil air bearing (32). The sealing disc (31) and the foil air bearing (32) connected in the same axis together constitute an axial thrust assembly (3). The axial thrust assembly (3) is located at the rear end of the rear end cover (28) of the motor (2). The sealing disc (31) and the rear end cover (28) cooperate to form a relatively sealed space.
5. The volute centrifugal fan according to claim 1, characterized in that: The foil air bearing (32) includes foil (321) and thrust plate (322). The thrust plate (322) is fixedly connected to the motor shaft (21). There are two foils (321). The two foils (321) are evenly distributed at both ends of the thrust plate (322) along its circumference. Each foil (321) has at least two fixing points along its circumference that are fixedly connected to the motor end cover or sealing plate (31). There is a gap between two adjacent fixing points on the same side where gas can flow freely.
6. The volute centrifugal fan according to claim 3, characterized in that: The bearings connected to both ends of the motor shaft (21) are a first angular contact bearing (24) and a second angular contact bearing (25), respectively. Wave springs are provided between the inner and outer rings at both ends of the first angular contact bearing (24) and the second angular contact bearing (25).
7. The volute centrifugal fan according to claim 6, characterized in that: The first angular contact bearing (24) is disposed on the inner side of the rear end of the front end cover (29), the second angular contact bearing (25) is disposed in the bearing seat at the rear end cover (28), the end of the motor shaft (21) extends rearward to pass through the rear end cover (28) and is connected to the fan blade (26) disposed on the outer side of the rear end cover (28), and a fan cover (27) is sleeved on the outside of the rear end cover (28).
8. The volute centrifugal fan according to claim 1, characterized in that: The motor (2) is also provided with an oil seal (4), which is connected to the outer side of the motor shaft (21) through a rotatable connection gap.
9. The volute centrifugal fan according to claim 1, characterized in that: The motor (2) is also provided with an O-ring (5), which is connected between the connection gap of two adjacent connectors.