阅读说明：本技术 转轴结构、离心式空气压缩机以及车辆 (Rotating shaft structure, centrifugal air compressor and vehicle ) 是由 陈玉辉 刘华 张治平 谭超 梁湖 钟瑞兴 于 2021-10-09 设计创作，主要内容包括：本发明涉及一种转轴结构、离心式空气压缩机以及车辆,转轴结构包括：转子,包括在轴向方向上依次设置的第一轴段和第二轴段；叶轮组件,包括至少一个叶轮,叶轮套设于第一轴段和/或第二轴段；止推盘,套设于转子的第一轴段；一级径向轴承,套设于转子的第一轴段；以及二级径向轴承,套设于转子的第二轴段；其中,一级径向轴承的长度大于二级径向轴承的长度,以使一级径向轴承的单位面积受力大小等于二级径向轴承的单位面积受力大小。上述转轴结构,通过增加一级径向轴承的长度,进而减小了一级径向轴承的径向支撑波箔的单位面积的受力大小,从而可避免转子向第一轴段所在侧发生倾斜,确保离心式空气压缩机平稳运行。(The invention relates to a rotating shaft structure, a centrifugal air compressor and a vehicle, wherein the rotating shaft structure comprises: the rotor comprises a first shaft section and a second shaft section which are sequentially arranged in the axial direction; the impeller assembly comprises at least one impeller, and the impeller is sleeved on the first shaft section and/or the second shaft section; the thrust disc is sleeved on the first shaft section of the rotor; the first-stage radial bearing is sleeved on the first shaft section of the rotor; the second-stage radial bearing is sleeved on the second shaft section of the rotor; the length of the first-stage radial bearing is larger than that of the second-stage radial bearing, so that the stress of the first-stage radial bearing per unit area is equal to that of the second-stage radial bearing per unit area. Above-mentioned pivot structure, through the length that increases one-level journal bearing, and then reduced one-level journal bearing's radial support ripples foil's unit area's atress size to can avoid the rotor to take place to incline to first shaft section place side, ensure centrifugal air compressor even running.)

1. A hinge structure, comprising:

a rotor (221) comprising a first shaft segment (2214) and a second shaft segment (2216);

an impeller assembly comprising at least one impeller sleeved to the first shaft section (2214) and/or the second shaft section (2216);

a thrust disk (224) sleeved on the first shaft section (2214) of the rotor (221);

a primary radial bearing (227) sleeved on the first shaft section (2214) of the rotor (221); and

a secondary radial bearing (228) sleeved on the second shaft section (2216) of the rotor (221);

wherein the length of the primary radial bearing (227) is larger than that of the secondary radial bearing (228), so that the force applied to the primary radial bearing (227) per unit area is equal to that of the secondary radial bearing (228).

2. A shaft structure according to claim 1, wherein the primary radial bearing (227) and the secondary radial bearing (228) are both foil hydrodynamic gas radial bearings.

3. The shaft structure according to claim 1, characterized in that the distance of the center of gravity of the shaft structure on the side where the primary radial bearing (227) is located from the center of gravity of the shaft structure is defined as L1, the distance of the center of gravity of the shaft structure on the side where the secondary radial bearing (228) is located from the center of gravity of the shaft structure is defined as L2, the length of the primary radial bearing (227) is defined as L1, and the length of the secondary radial bearing (228) is defined as L2;

the relationship among the 11, the L2, the L1, and the L2 satisfies: l1xL1 ═ l2xL 2.

4. The hinge structure of claim 1, wherein the relationship between L1 and L2 satisfies: l1 ═ nL2, where 1.2< n < 1.7.

5. A shaft structure according to claim 1, characterized in that the diameter of the primary radial bearing (227) and the diameter of the secondary radial bearing (228) are equal.

6. The rotary shaft structure according to claim 1, wherein a center of gravity of a side of the rotary shaft structure where the primary radial bearing (227) is located is defined as F1, a center of gravity of a side of the rotary shaft structure where the secondary radial bearing (228) is located is defined as F2, a distance of a center of gravity of a side of the rotary shaft structure where the primary radial bearing (227) is located from the center of gravity of the rotary shaft structure is defined as l1, and a distance of a center of gravity of a side of the rotary shaft structure where the secondary radial bearing (228) is located from the center of gravity of the rotary shaft structure is defined as l 2;

a weight reduction portion is provided in the first shaft segment (2214) of the rotor (221) such that a relationship among the F1, the F2, the l1, and the l2 satisfies: f1xl1 ═ F2xl 2.

7. The rotating shaft structure according to claim 6, wherein the first shaft segment (2214) of the rotor (221) is opened with a first center hole (2214a), the second shaft segment (2216) of the rotor (221) is opened with a second center hole (2216a), and the weight-reduced portion is configured as a recess opened in a wall of the first center hole (2214 a).

8. The rotary shaft structure according to claim 7, wherein the weight-reduced portion circumferentially surrounds the first center hole (2214a) and extends from one end in the axial direction of the first center hole (2214a) to the other end in the axial direction of the first center hole (2214 a).

9. A centrifugal air compressor characterized by comprising a rotary shaft structure according to any one of claims 1 to 8.

10. A vehicle comprising a fuel cell system and a centrifugal air compressor according to claim 9 for providing a high pressure air supply to the fuel cell system.

Technical Field

The invention relates to the technical field of compressors, in particular to a rotating shaft structure, a centrifugal air compressor and a vehicle.

Background

The hydrogen fuel cell is a device for generating electric energy through chemical reaction between hydrogen and oxygen, and an electric automobile adopting the hydrogen fuel cell is one of the breakthrough of the current new energy automobile and has the advantages of high power performance, quick hydrogenation, long endurance and the like. The air compressor plays an important role in a hydrogen fuel cell vehicle as a component for supplying a high-pressure air source to a fuel cell system.

Currently, common air compressors include centrifugal air compressors, screw air compressors, scroll air compressors, and the like. Compared with screw compressor and scroll compressor, the centrifugal air compressor drives gas to rotate at high speed by the impeller, so that the gas generates centrifugal force, and because the gas expands and flows in the impeller, the flow speed and pressure of the gas passing through the impeller are improved to continuously produce compressed air, thereby providing a gas source with higher pressure ratio and remarkably improving the power density and the overall performance of the electric pile. The dynamic pressure gas bearing is one of the core components of the centrifugal air compressor, has the advantages of small friction loss, high rotating speed, good high-temperature stability, no need of lubricating oil and the like, and has very wide application prospect.

The centrifugal air compressor comprises a motor stator and a rotating shaft structure, wherein the rotating shaft structure can rotate at a high speed relative to the motor stator under the action of electromagnetic field force. The electronic rotor comprises a rotor and two foil dynamical pressure gas radial bearings which are respectively sleeved at two ends of the rotor, and the foil dynamical pressure gas radial bearings realize a supporting effect based on a dynamic pressure effect. As shown in fig. 1, the foil dynamical pressure gas radial bearing 100 includes a bearing housing 120, and a bump foil 140 and a top foil 160 accommodated in the bearing housing 120, wherein the bump foil 140 is located between the bearing housing 120 and the top foil 160. The rotor is eccentric with respect to the foil hydrodynamic radial bearing 100 under the action of gravity, and thus forms a wedge-shaped gap with the inner surface of the foil hydrodynamic radial bearing 100. When the rotor rotates at high speed, gas with certain viscosity is continuously brought into the wedge-shaped gap, the gas continuously enters to enable the gas film to generate certain pressure, and when the gas film force is enough to balance the load of the rotor, the rotor is completely separated from the foil dynamic pressure gas radial bearing 100, and the process generated by the gas film is called dynamic pressure effect.

As can be seen from the above-described principle and the bearing structure, when the foil dynamical pressure gas radial bearing operates, a high-pressure gas film is formed by the dynamic pressure effect, and the bump foil of the foil dynamical pressure gas radial bearing provides a pressure support rotor for the gas film by deforming, and the greater the load of the foil dynamical pressure gas radial bearing, the greater the deformation amount of the bump foil therein.

In the prior art, the structural strength of the bump foil is usually designed to meet the deformation range according to the load range of the foil dynamical pressure gas radial bearing when the air compressor works, so that the rotor-bearing system works in a reasonable clearance. And when the air compressor works under a high-load condition, the bearing bump foil realizes certain deformation, so that larger bearing capacity is provided for the rotor.

However, because the bump foil is of an elastic structure, when the air compressor is subjected to abnormal impact (such as fault shutdown, surge, sudden acceleration and deceleration of an automobile, and the like), the foil dynamical pressure gas radial bearing at one end of the rotor is subjected to additional impact load, so that the bump foil is deformed excessively, the bearing capacity of the top foil is increased suddenly, an air film is easily damaged, and the motor shaft and the foil dynamical pressure gas radial bearing are directly rubbed or abraded, or the rotor of the air compressor and a static part are rubbed or abraded. In addition, when the single loads of the radial bearing foils of the foil dynamical pressure gas radial bearings at the two ends of the rotor are not equal under the high rotating speed of the air compressor, the rotor is easy to incline towards one side, so that an air film formed between the foil dynamical pressure gas radial bearings and the rotor is unstable, and the phenomenon that the rotor collides with the foil dynamical pressure gas radial bearings occurs.

Therefore, in order to improve the operational reliability of the centrifugal air compressor, it is necessary to develop a method for adjusting the center of gravity of the rotor of the centrifugal air compressor to ensure smooth operation of the air compressor.

Disclosure of Invention

The invention provides a rotating shaft structure, a centrifugal air compressor and a vehicle, aiming at the problem that a rotor of an air compressor inclines to one side and collides with a bearing.

According to an aspect of the present application, there is provided a spindle structure including:

a rotor comprising a first shaft section and a second shaft section;

the impeller assembly comprises at least one impeller, and the impeller is sleeved on the first shaft section and/or the second shaft section;

the thrust disc is sleeved on the first shaft section of the rotor;

the first-stage radial bearing is sleeved on the first shaft section of the rotor; and

the second-stage radial bearing is sleeved on the second shaft section of the rotor;

the length of the first-stage radial bearing is larger than that of the second-stage radial bearing, so that the stress of the first-stage radial bearing per unit area is equal to that of the second-stage radial bearing per unit area.

In one embodiment, the primary and secondary radial bearings are both foil hydrodynamic gas radial bearings.

In one embodiment, a distance between a center of gravity of the primary radial bearing of the rotating shaft structure and a center of gravity of the rotating shaft structure is defined as L1, a distance between a center of gravity of the secondary radial bearing of the rotating shaft structure and a center of gravity of the rotating shaft structure is defined as L2, a length of the primary radial bearing is defined as L1, and a length of the secondary radial bearing is defined as L2;

the relationship among the 11, the L2, the L1, and the L2 satisfies: l1xL1 ═ l2xL 2.

In one embodiment, the relationship between the L1 and the L2 satisfies: l1 ═ nL2, where 1.2< n < 1.7.

In one embodiment, the diameter of the primary radial bearing and the diameter of the secondary radial bearing are equal.

In one embodiment, a center of gravity of a side where the primary radial bearing of the rotating shaft structure is located is defined as F1, a center of gravity of a side where the secondary radial bearing of the rotating shaft structure is located is defined as F2, a distance between a center of gravity of a side where the primary radial bearing of the rotating shaft structure is located and a center of gravity of the rotating shaft structure is defined as l1, and a distance between a center of gravity of a side where the secondary radial bearing of the rotating shaft structure is located and a center of gravity of the rotating shaft structure is defined as l 2;

a weight reduction portion is provided in the first shaft section of the rotor such that a relationship among the F1, the F2, the l1, and the l2 satisfies: f1xl1 ═ F2xl 2.

In one embodiment, the first shaft section of the rotor defines a first central aperture, the second shaft section of the rotor defines a second central aperture, and the weight-reducing portion is configured as a recess defined in a wall of the first central aperture.

In one embodiment, the weight-reduced portion circumferentially surrounds the first center hole and extends from one end of the first center hole in the axial direction to the other end of the first center hole in the axial direction.

According to another aspect of the present application, there is provided a centrifugal air compressor including the above-described rotary shaft structure.

According to another aspect of the present application, a vehicle is provided, which includes a fuel cell system and the centrifugal air compressor mentioned above, wherein the centrifugal air compressor is used for providing a high-pressure air source for the fuel cell system.

Above-mentioned pivot structure, through the length that increases one-level journal bearing, and then reduced one-level journal bearing's radial support ripples paper tinsel's unit area's atress size to can avoid the rotor to incline to first shaft section place side, prevent that the air film that forms between one-level journal bearing and the rotor is unstable, eliminate the rotor and the journal bearing between bump, finally ensure centrifugal air compressor even running.

Drawings

FIG. 1 is a schematic view of a foil hydrodynamic gas radial bearing;

FIG. 2 is a schematic diagram of a centrifugal air compressor according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a rotating shaft structure of a centrifugal air compressor according to an embodiment of the present invention;

FIG. 4 is a schematic structural view of a rotary shaft structure of a centrifugal air compressor according to another embodiment of the present invention;

the reference numbers illustrate:

200. a centrifugal air compressor; 210. a housing; 212. a motor cylinder; 214. a first-stage volute; 216. a second-stage volute; 220. a rotating shaft structure; 221. a rotor; 2212. a permanent magnet; 2214. a first shaft section; 2214a, first central hole; 2216. a second shaft section; 2216a, second central hole; 2218. installing a sleeve; 222. a first-stage impeller; 223. a secondary impeller; 224. a thrust plate; 225. a primary lock nut; 226. a secondary lock nut; 227. a primary radial bearing; 228. a secondary radial bearing; 230. a motor stator; 240. a first stage diffuser; 250. a secondary diffuser; 260. a bearing support; 270. and comb teeth.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Referring to fig. 2 to 4, fig. 2 is a schematic structural view illustrating a centrifugal air compressor according to an embodiment of the present invention, and fig. 3 is a schematic structural view illustrating a structure of a rotating shaft of the centrifugal air compressor according to an embodiment of the present invention; fig. 4 is a schematic structural view showing a structure of a rotating shaft of a centrifugal air compressor in another embodiment of the present invention.

An embodiment of the present invention provides a centrifugal air compressor 200, which includes a housing 210, a rotating shaft structure 220, a motor stator 230, a first-stage diffuser 240, a second-stage diffuser 250, a bearing support 260, and a comb 270.

The housing 210 includes a motor cylinder 212, a first-stage volute 214, and a second-stage volute 216, the motor cylinder 212 is a cylindrical structure with openings at two ends to form a motor accommodating chamber, and the first-stage volute 214 and the second-stage volute 216 are respectively disposed at two opposite ends of the motor cylinder 212 in the axial direction. The motor stator 230 is fixedly disposed in the motor receiving cavity and forms a mounting hole for the rotor 221.

The rotating shaft structure 220 is rotatably disposed in the motor accommodating cavity and passes through the rotor 221 mounting hole, and includes a rotor 221, an impeller assembly, a thrust disk 224, a first-stage locking nut 225, a second-stage locking nut 226, a first-stage radial bearing 227, and a second-stage radial bearing 228.

As shown in fig. 2 and fig. 3, the rotor 221 includes a permanent magnet 2212, a first shaft segment 2214, a second shaft segment 2216, and a mounting sleeve 2218, the permanent magnet 2212 is a solid cylindrical structure formed by magnetic steel, the first shaft segment 2214 and the second shaft segment 2216 are respectively disposed at two opposite ends of the permanent magnet 2212 in the axial direction, and the mounting sleeve 2218 is sleeved outside the first shaft segment 2214, the permanent magnet 2212, and the second shaft segment 2216, so that the first shaft segment 2214, the permanent magnet 2212, and the second shaft segment 2216 are fixedly connected to each other. The permanent magnet 2212 can generate a magnetic field for driving the rotating shaft structure 220 to rotate when the windings of the motor stator 230 are energized.

The impeller assembly includes a primary impeller 222 and a secondary impeller 223, the primary impeller 222 is mounted on one end of the first shaft segment 2214 far away from the permanent magnet 2212 in the axial direction through a primary lock nut 225, and is arranged at a gap with the primary volute 214. The secondary impeller 223 is mounted to an end of the second shaft segment 2216 remote from the permanent magnet 2212 in the axial direction by a secondary lock nut 226, and is disposed in a gap with the secondary volute 216.

The primary radial bearing 227 is sleeved on the first shaft section 2214 and located on one side of the primary impeller 222 close to the permanent magnet 2212, and the secondary radial bearing 228 is sleeved on the second shaft section 2216 and located on one side of the secondary impeller 223 close to the permanent magnet 2212. Thus, the first-stage radial bearing 227 and the second-stage radial bearing 228 are supporting points of the rotor 221, and are installed opposite to each other at opposite ends of the rotor 221, and when the centrifugal air compressor 200 operates at a high speed, an air film is formed between the rotor 221 and the first-stage radial bearing 227 and the second-stage radial bearing 228, so that the rotor 221 is suspended without being connected to the first-stage radial bearing 227 and the second-stage radial bearing 228.

Further, the primary radial bearing 227 and the secondary radial bearing 228 are both foil hydrodynamic gas radial bearings, each of which includes a bearing housing, and a radial support bump foil and a radial top foil mounted on the bearing housing, and the radial support bump foil is located between the radial bearing seat and the radial top foil.

The thrust disk 224 is sleeved on the first shaft section 2214 and located between the first-stage impeller 222 and the first-stage radial bearing 227, the thrust disk 224 is in interference fit with the first shaft section 2214, and when the centrifugal air compressor 200 operates, the thrust disk 224 and the rotor 221 move synchronously, so that large axial movement of the rotor 221 is prevented.

The first-stage diffuser 240 is sleeved outside the thrust disc 224 and is in clearance fit with the thrust disc 224, and the first-stage diffuser 240 is provided with comb teeth 270 which play a role in sealing axially and radially. The second-stage diffuser 250 is sleeved outside the second-stage radial bearing 228 and is fixedly connected with the second-stage radial bearing 228 through a fastener such as a bolt.

The bearing support 260 is sleeved outside the first-stage radial bearing 227 and is fixedly connected with the motor cylinder 212 and the first-stage radial bearing 227 through fasteners such as bolts, so that the first-stage radial bearing 227 is supported. The comb teeth 270 are sleeved on the second shaft segment 2216 and located between the secondary radial bearing 228 and the secondary impeller 223, and the groove comb teeth 270 are uniformly distributed in the radial direction and the axial direction of the comb teeth 270 to play a role in sealing.

As described in the background, in the centrifugal air compressor 200, since the thrust disk 224 is mounted on the first shaft section 2214 of the rotor 221, the center of gravity of the entire rotating shaft structure 220 is biased to the side of the first shaft section 2214, and the primary radial bearing 227 is the only supporting point of the entire rotating shaft structure 220, when the axial force applied to the structure is too large, the rotor 221 is tilted to collide the primary impeller 222 with the primary volute 214, thereby reducing the reliability of the entire centrifugal air compressor 200.

In order to solve the above problem, in the rotor 221 structure of the present application, the diameters of the primary radial bearing 227 and the secondary radial bearing 228 are equal, and the length of the primary radial bearing 227 is greater than the length of the secondary radial bearing 228, so that the force applied per unit area of the primary radial bearing 227 is equal to the force applied per unit area of the secondary radial bearing 228, that is, the force applied per unit area of the radial support wave foil of the primary radial bearing 227 is equal to the force applied per unit area of the radial support wave foil of the secondary radial bearing 228.

Therefore, the length of the first-stage radial bearing 227 is increased, and the stress of the unit area of the radial supporting wave foil of the first-stage radial bearing 227 is further reduced, so that the rotor 221 can be prevented from inclining to the side where the first shaft section 2214 is located, an air film formed between the first-stage radial bearing 227 and the rotor 221 is prevented from being unstable, collision between the rotor 221 and the first-stage radial bearing 227 is eliminated, and finally the smooth operation of the centrifugal air compressor 200 is ensured.

Specifically, the center of gravity of the rotating shaft structure 220 is defined as G, the center of gravity of the side where the primary radial bearing 227 is located is defined as F1, the distance from the center of gravity F1 of the side where the primary radial bearing 227 of the rotating shaft structure 220 is located to the center of gravity G of the rotating shaft structure 220 is defined as L1, the distance from the center of gravity of the side where the secondary radial bearing 228 of the rotating shaft structure 220 is defined as F2, the distance from the center of gravity F2 of the side where the secondary radial bearing 228 of the rotating shaft structure 220 is located to the center of gravity G of the rotating shaft structure 220 is defined as L2, the length of the primary radial bearing 227 is defined as L1, and the length of the secondary radial bearing 228 is defined as L2. The relationship among 11, L2, L1, and L2 described above satisfies: l1xL1 ═ l2xL 2.

Thus, approximately F — DxL, where (D is the diameter of the primary radial bearing 227 or the secondary radial bearing 228, and L is the length of the primary radial bearing 227 or the secondary radial bearing 228), since the diameter of the primary radial bearing 227 and the diameter of the secondary radial bearing 228 are equal, the moments of the primary radial bearing 227 and the secondary radial bearing 228 can be obtained to satisfy: f1xl1 ═ F2xl 2. Since the moments of the primary radial bearing 227 and the secondary radial bearing 228 satisfy the above formula, smooth operation of the rotor 221 structure is ensured. As a preferred embodiment, the relationship between L1 and L2 satisfies: l1 ═ nL2, where 1.2< n < 1.7. May be connected, and the specific value of n is not limited thereto and may be set as needed to meet different requirements.

It should be noted that the primary radial bearing 227 of the rotating shaft structure 220 is located in a range from the center point of the permanent magnet 2212 to the end surface of the first shaft segment 2214, and the secondary radial bearing 228 of the rotating shaft structure 220 is located in a range from the center point of the permanent magnet 2212 to the end surface of the second shaft segment 2216.

As shown in fig. 3 and 4, in some embodiments, in order to avoid the length of the primary radial bearing 227 from being too long, a weight reduction portion may be further formed in the first shaft section 2214 of the rotor 221 in a manner of removing material on the basis of increasing the length of the primary radial bearing 227 to reduce the weight of the first shaft section 2214, so that the relationship between the gravity center F1 on the side where the primary radial bearing 227 of the rotating shaft structure 220 is located, the gravity center F2 on the side where the secondary radial bearing 228 of the rotating shaft structure 220 is located, the distance l1 of the gravity center F1 on the side where the primary radial bearing 227 of the rotating shaft structure 220 is located relative to the gravity center G of the rotating shaft structure 220, and the distance l2 of the gravity center F2 on the side where the secondary radial bearing 228 of the rotating shaft structure 220 is located relative to the gravity center G of the rotating shaft structure 220 satisfies: f1xl1 ═ F2xl 2.

Specifically, in some embodiments, the first shaft segment 2214 of the rotor 221 defines a first central hole 2214a, the second shaft segment 2216 of the rotor 221 defines a second central hole 2216a, the weight-reduced portion is configured as a recess defined in a wall of the first central hole 2214a, and the weight-reduced portion circumferentially surrounds the first central hole 2214a and extends from one axial end of the first central hole 2214a to the other axial end of the first central hole 2214 a. Thus, the weight of the first shaft segment 2214 is reduced by removing materials, so that the gravity center of the rotating shaft structure 220 is further ensured to be positioned at the center of the motor, and the problem of unstable axial force during the operation of the centrifugal air compressor 200 is solved.

The rotating shaft structure 220 and the centrifugal air compressor 200 enable the radial supporting wave foil of the first-stage radial bearing 227 and the radial supporting wave foil of the second-stage radial bearing 228 to be equal in stress magnitude in unit area by adjusting the lengths of the first-stage radial bearing 227 and the second-stage radial bearing 228 and removing materials in the first shaft section 2214, effectively adjust the center of gravity of the rotating shaft structure 220, avoid the rotor 221 structure from inclining to the side where the thrust disc 224 is located, further eliminate the problem that an air film formed between the first-stage radial bearing 227 and the rotor 221 is unstable to cause the collision phenomenon of the rotor 221, avoid the collision and abrasion of the first-stage impeller 222 and the first-stage volute 214, and ensure the smooth operation of the centrifugal air compressor 200.

The application also provides a vehicle, which comprises a fuel cell system and the centrifugal air compressor 200, wherein the centrifugal air compressor 200 is used for providing a high-pressure air source for the fuel cell system.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.