Dynamic pressure gas suspension bearing structure and motor

Abstract

This invention discloses a dynamic pressure air suspension bearing structure, comprising a bearing housing, an air suspension bearing, and a motor shaft. The air suspension bearing is a frustoconical type with an outer end smaller than its inner end, and the inner wall of the inner sleeve hole of its top foil layer is a conical inner wall. The bearing housing has a conical seat hole. The motor shaft has frustoconical sections at both ends for mounting the air suspension bearing, with the smaller end facing outward. These sections have outer conical surfaces adapted to the conical inner walls. The air suspension bearing is installed in the seat hole of the bearing housing, and the frustoconical section of the motor shaft is fitted into the inner sleeve hole of the air suspension bearing. A wedge-shaped gap is formed between the outer conical surface of the motor shaft and the conical inner wall of the air suspension bearing, allowing airflow to pass through. This invention also discloses a motor employing the above-mentioned dynamic pressure air suspension bearing structure.

Description

Technical Field

[0001] This invention relates to a dynamic pressure air suspension bearing structure and motor, belonging to the field of air suspension bearing technology. Background Technology

[0002] The development of high-speed and high-power-density motors has spurred the emergence of new shaft support methods, one of which is the air suspension bearing. Due to its simple structure, lack of contact friction, oil-free operation, and low losses, the air suspension bearing is highly suitable for small and medium-power high-speed motors.

[0003] As the speed of motors supported by air bearings increases, there is a need for more compact rotor dimensions and simpler structures. This requires finding ways to compress the axial dimensions of the rotor, improve rotor stiffness and modal characteristics, and ensure that the rotor's critical speed avoids the motor's operating speed.

[0004] like Figure 11 As shown, the air suspension bearing 2 includes an annular elastic upper elastic wave foil layer 202 and an annular top foil layer 201. The air suspension bearing 2 has a bearing seat 1. The elastic wave foil layer 202 is located between the bearing seat 1 and the top foil layer 201. The top foil layer 201 is sleeved on the outer periphery of the motor shaft 3, and there is a wedge-shaped gap 4 between the inner wall of the top foil layer 201 and the outer peripheral surface of the motor shaft 3. When not in operation, the motor shaft 3 is pressed against the lower side of the inner wall of the top foil layer 201. When the motor shaft 3 rotates at high speed, the gas in the wedge-shaped gap 4 forms a gas film with aerodynamic pressure, which completely separates the motor shaft 3 from the top foil layer 201, thereby realizing the suspension of the motor shaft 3.

[0005] like Figure 12 As shown, the existing motor 100 with dynamic pressure air suspension bearing structure requires radial air suspension bearing 2001 and axial air suspension bearing 2002 at both ends to cope with the radial load impact and axial load impact on the motor shaft. Both structures need to meet the set buoyancy requirements. The presence of the axial air suspension bearing increases the axial length at both ends of the motor, which goes against the development trend of motor compaction and miniaturization, and also significantly increases the complexity of the structure.

[0006] Another drawback of existing motors using dynamic pressure air suspension bearings is that the bearings have a low upper limit for withstanding radial and axial load impacts and require high speeds to maintain, which greatly limits the application range of air suspension bearings. Summary of the Invention

[0007] The technical problem to be solved by this invention is: how to simplify the structure of air suspension bearings and shorten the axial length of motors using dynamic pressure air suspension bearings.

[0008] To address the above problems, the technical solution proposed by this invention is as follows: A dynamic pressure air suspension bearing structure includes a bearing housing, an air suspension bearing, and a motor shaft. The air suspension bearing is a frustoconical type with an outer end smaller than its inner end. The inner wall of the inner sleeve hole of its top foil layer is a conical inner wall. The seat sleeve hole of the bearing housing is a conical hole. Both ends of the motor shaft have frustoconical sections with the smaller end facing outward for mounting the air suspension bearing. These sections have outer conical surfaces that adapt to the conical inner walls. The air suspension bearing is installed in the seat sleeve hole of the bearing housing. The frustoconical section of the motor shaft is fitted into the inner sleeve hole of the air suspension bearing. A wedge-shaped gap is formed between its outer conical surface and the conical inner wall of the air suspension bearing, allowing airflow to pass through.

[0009] Multiple spiral blades of equal arc length are provided on the motor shaft outside the air suspension bearing to push airflow into the wedge-shaped gap.

[0010] The outer cone of the frustum section extends outward beyond the bearing housing to form a conical extension section, and the helical blade is disposed on the conical extension section.

[0011] The outer part of the motor shaft cone section, close to the bearing seat, is a cylindrical section, and the helical blades are located on the cylindrical section.

[0012] An annular wind-gathering shroud surrounds the motor shaft on the outside of the bearing housing, and the spiral blades are located inside the annular wind-gathering shroud.

[0013] The outer surface of the spiral blade is close to the inner wall of the annular wind-gathering shroud.

[0014] The inner wall of the annular wind-gathering shroud is an arc-shaped guide surface from the outside to the inside, and the inner end of the arc-shaped guide surface is close to the outer end of the conical inner wall of the air suspension bearing.

[0015] The outer end of the conical inner wall is connected to a windbreak ring that extends radially outward.

[0016] An electric motor employing a dynamic pressure air suspension bearing structure includes a rotor mounted on the motor shaft, a stator sleeved around the outer periphery of the rotor, and a motor housing covering and fixing the stator. The motor housing has mounting holes one and two at its ends for mounting bearing seats. The improvement lies in that: the bearing seat at one end is a fixed bearing seat fixed in mounting hole one, while the bearing seat at the other end is a movable bearing seat installed in mounting hole two, capable of axial sliding over a set distance. When the motor shaft is stationary, the movable bearing seat is pushed towards the fixed bearing seat, reducing the wedge-shaped gap between the conical sections at both ends of the motor shaft and their respective air suspension bearings. When the motor shaft is in operation, the wedge-shaped gap expands under the action of the dynamic pressure airflow, causing the movable bearing seat to retract.

[0017] An annular boss is provided on the outer periphery of the movable bearing housing located at one end inside the motor housing. A compression spring is provided between the annular boss and the inner wall of the motor housing at the edge of the mounting hole. The compression spring provides a force to push the movable bearing housing, the motor shaft, and the rotor on the motor shaft together toward the fixed bearing housing.

[0018] The wedge-shaped gap is located at one end of the annular port inside the motor housing, which is aligned with the coil end of the stator coil. Beneficial effects

[0019] Compared to existing motors that use a dynamic pressure air suspension bearing structure, which require radial and axial air suspension bearings at both ends, the motor with a dynamic pressure air suspension bearing structure provided by this invention only requires one air suspension bearing at each end, which not only simplifies the air suspension structure of the motor but also shortens the length of the motor. Attached Figure Description

[0020] Figure 1 This is a cross-sectional schematic diagram of the motor using the dynamic pressure air suspension bearing structure described in Embodiment 1; Figure 2 This is a schematic diagram showing the disassembly of the air suspension bearing and the motor shaft as described in Embodiment 1; Figure 3 for Figure 1 A partial schematic diagram; Figure 4 for Figure 3 A partial schematic diagram, showing the decomposition of the force exerted on the motor shaft by the air pressure in the wedge-shaped gap; Figure 5 This is a cross-sectional schematic diagram of the motor employing the dynamic pressure air suspension bearing structure described in Embodiment 2; Figure 6 This is a schematic diagram showing the disassembly of the bearing housing, air suspension bearing, and motor shaft as described in Embodiment 1; Figure 7 for Figure 5 A partial schematic diagram; Figure 8 This is a partial schematic diagram of the motor using a dynamic pressure air suspension bearing structure as described in Embodiment 3; Figure 9 This is a cross-sectional schematic diagram of the motor using the dynamic pressure air suspension bearing structure in Embodiments 4 and 5; Figure 10 for Figure 9 A partial schematic diagram; Figure 11 This is a schematic diagram of a cross-section of a conventional air suspension bearing; Figure 12 This is a schematic diagram of the air suspension bearing layout of an existing motor using a dynamic pressure air suspension bearing structure. The diagram shows that one end of the motor using the dynamic pressure air suspension bearing structure has a radial air suspension bearing and an axial air suspension bearing. In the diagram: 100, Motor; 1001, Motor housing; 1002, Rotor; 1003, Stator; 10031, Coil end; 1, Bearing housing; 101, Sleeve hole; 102, Fixed bearing housing; 103, Movable bearing housing; 104, Annular boss; 105, Compression spring; 2, Air suspension bearing; 201, Top foil layer; 2011, Conical inner wall; 202, Elastic corrugated foil layer; 2001, Radial air suspension bearing; 2002, Axial air suspension bearing; 3, Motor shaft; 301, Frustum section; 3011, Outer conical surface; 302, Conical surface extension; 303, Cylindrical section; 4, Wedge-shaped gap; 5, Helical blade; 6, Annular wind concentrator; 601, Arc-shaped guide surface; 7, Wind deflector ring. Detailed Implementation

[0021] The present invention will be further described below with reference to embodiments and accompanying drawings: Example 1

[0022] like Figure 1-4 As shown, a dynamic pressure air suspension bearing structure includes a bearing housing 1, an air suspension bearing 2, and a motor shaft 3. The air suspension bearing 2 is a frustoconical type with the outer end smaller than the inner end. The inner wall of the inner sleeve hole of its top foil layer 201 is a conical inner wall 2011. The seat hole 101 of the bearing housing 1 is a conical hole. The motor shaft 3 has frustoconical sections 301 at both ends for mounting the air suspension bearing 2 with the smaller end facing outward. These sections have an outer conical surface 3011 that matches the conical inner wall 2011. The air suspension bearing 2 is installed in the seat hole 101 of the bearing housing 1. The frustoconical section 301 of the motor shaft 3 is fitted into the inner sleeve hole of the air suspension bearing 2. There is a wedge-shaped gap 4 between its outer conical surface 3011 and the conical inner wall 2011 of the air suspension bearing 2, which allows airflow to pass through. When the motor shaft rotates at high speed, the air in the wedge-shaped gap 4 forms a high-pressure air film on the outer conical surface 3011 of the motor shaft 3, creating a pressure F on the conical inner wall 2011 of the air suspension bearing 2 sufficient to separate the air suspension bearing 2 from the motor shaft 3. Since the inner wall of the upper air suspension bearing 2 and the outer surface of the motor shaft 3 are in an inclined conical fit, the pressure F can be decomposed into radial force F1 and axial force F2. The radial force F1 provides radial support to the motor shaft 3, suspending it, while the axial force F2 resists the axial movement of the motor shaft 3 (the two ends of the motor shaft 3 receive completely opposite axial forces F2). Thus, compared to the prior art motor 100 using a dynamic pressure air suspension bearing structure, which requires radial air suspension bearings 2001 and axial air suspension bearings 2002 at each end, this solution only requires one such air suspension bearing 2 at each end of the motor 100 using a dynamic pressure air suspension bearing structure. This not only simplifies the air suspension structure of the motor 100 using a dynamic pressure air suspension bearing structure but also shortens the length of the motor 100 using a dynamic pressure air suspension bearing structure.

[0023] Wedge gap 4: The gap between the inner wall of the air suspension bearing and the outer circumferential surface of the motor shaft 3. In order to increase the air pressure of the air film, different products will set different surface mechanisms on the inner wall of the air suspension bearing or the outer circumferential surface of the motor shaft. Example 2

[0024] like Figure 5-7 As shown, this is a further improvement of Embodiment 1. Multiple helical blades 5, with equal arc lengths, are provided on the motor shaft 3 outside the air suspension bearing 2 to push airflow into the wedge-shaped gap 4. Because the motor shaft 3 rotates at very high speeds, the air pressure pushed by the helical blades 5 is very strong, significantly increasing the air pressure in the wedge-shaped gap 4, enhancing its resistance to load impacts, and thus achieving a more stable suspension effect.

[0025] The outer conical surface 3011 of the frustum section 301 extends outward from the bearing housing 1 to form a conical extension section 302, and the helical blade 5 is disposed on the conical extension section 302.

[0026] An annular wind-gathering shroud 6 is provided on the outside of the bearing housing 1, surrounding the motor shaft 3. The spiral blade 5 is located inside the annular wind-gathering shroud 6 to prevent the airflow pushed by the spiral blade 5 to the wedge-shaped gap 4 from spreading outward.

[0027] The outer surface of the spiral blade 5 is close to the inner wall of the annular wind-gathering shroud 6.

[0028] Furthermore, the inner wall of the annular wind-gathering cover 6 is an arc-shaped guide surface 601 extending from the outside to the inside. The inner end of the arc-shaped guide surface 601 is close to the outer end of the conical inner wall 2011 of the air suspension bearing 2, thereby guiding the airflow pushed by the spiral blade 5 into the wedge-shaped gap 4.

[0029] Furthermore, the outer end of the conical inner wall 2011 is connected to a radially outward-extending wind deflector ring 7 to prevent airflow from entering the elastic wave foil layer 202 between the top foil layer 201 and the bearing seat 1. Example 3

[0030] like Figure 8 As shown, the difference between this embodiment and the second embodiment is that the outer part of the cone section 301 of the motor shaft 3 is a cylindrical section 303 close to the bearing seat 1, and the spiral blade 5 is disposed on the cylindrical section 303. Example 4

[0031] like Figure 9 , 10As shown, a motor employing a dynamic pressure air suspension bearing structure includes a rotor 1002 mounted on the motor shaft 3, a stator 1003 sleeved around the outer periphery of the rotor 1002, and a motor housing 1001 covering and fixing the stator 1003. The motor housing 1001 has a mounting hole 1 and a mounting hole 2 at each end for mounting bearing seats. The bearing seat 1 at one end of the motor 100 is a fixed bearing seat 102 fixed in the mounting hole 1, while the bearing seat 1 at the other end is a movable bearing seat 103 capable of axial sliding by a set distance, mounted in the mounting hole 2. When the motor shaft 3 is stationary, the movable bearing seat 103 is pushed towards the fixed bearing seat 102, reducing the wedge-shaped gap 4 between the conical sections 301 at both ends of the motor shaft 3 and their respective air suspension bearings 2. When the motor shaft 3 is in operation, the wedge-shaped gap 4 widens under the action of the dynamic pressure airflow, causing the movable bearing seat 103 to retract. In this way, regardless of whether the motor 100 is in operating or non-operating condition, the coaxiality of the motor shaft 3 and the bearing housing 1 is very high, enabling their centerlines to basically coincide. This ensures that the stator 1003 is in a position close to the optimal cutting position with the rotor's magnetic field lines when it starts to rotate. Of course, due to the weight of the motor shaft 3 and its rotor, the centerline of the motor shaft 3 will inevitably be lower than the centerline of the bearing housing 1, regardless of whether it is in operating or non-operating condition.

[0032] Furthermore, an annular boss 104 is provided on the outer periphery of the movable bearing seat 103 located inside the motor housing 1001. A compression spring 105 is provided between the annular boss 104 and the inner wall of the motor housing 1001 at the edge of the mounting hole 2. The compression spring 105 provides a force to push the movable bearing seat 103, the motor shaft 3, and the rotor 1002 on the motor shaft 3 together toward the fixed bearing seat 102. The basic principle of this setting is that the process of the motor shaft 3 stopping rotation is a process of changing from high speed to zero speed. During the process of the motor shaft 3 speed decreasing, the pneumatic pressure in the wedge gap 4 at both ends gradually decreases, but the motor shaft 3 is still in a suspended state. The compression spring 105 can closely follow the decrease of pneumatic pressure and push the movable bearing seat 103, the stator 1003, and the rotor 1002 fixed on it, thereby reducing the distance of the wedge gap 4 between the conical sections 301 at both ends of the motor shaft 3 and their respective air suspension bearings 2. When the speed of motor shaft 3 decreases to 0, the pneumatic pressure in the wedge-shaped gaps 4 at both ends disappears, and motor shaft 3 loses its levitation force. The lower side of the outer conical surface 3011 of the two conical sections 301 at both ends is pressed against the lower side of the conical inner wall 2011 of their respective air suspension bearings 2, but the upper middle part of the wedge-shaped gap 4 still exists. When the speed of motor shaft 3 increases from 0 to high speed, the pneumatic pressure in the upper middle part of the wedge-shaped gap 4 between the outer conical surface 3011 and the conical inner wall 2011 suddenly increases. The upper middle part of the wedge-shaped gap 4 expands between the lower side of the previously pressed outer conical surface 3011 and the lower side of the conical inner wall 2011, making motor shaft 3 levitate. At the same time, as the speed increases, the pneumatic pressure overcomes the pressure of the compression spring 105, and the movable bearing seat 103 retracts, and the wedge-shaped gap 4 returns to the proper spacing. Example 5

[0033] like Figure 9 , 10 As shown, the annular port of one end of the wedge gap 4 inside the motor housing 1001 is aligned with the coil end 10031 of the stator coil. In this way, the airflow entering the motor housing 1001 through the wedge gap 4 can blow onto the coil end 10031 of the stator coil, significantly improving the cooling effect of the stator coil.

[0034] The above embodiments are only used to describe the present invention more clearly, and should not be regarded as limiting the scope of protection covered by the present invention. Any equivalent modifications should be regarded as falling within the scope of protection covered by the present invention.

Claims

1. A dynamic pressure air suspension bearing structure, comprising a bearing housing (1), an air suspension bearing (2), and a motor shaft (3), characterized in that: The air suspension bearing (2) is a frustoconical type with the outer end smaller than the inner end. The inner wall of the inner sleeve hole of its top foil layer (201) is a conical inner wall (2011). The seat hole (101) of the bearing seat (1) is a conical hole. The motor shaft (3) has frustoconical sections (301) with the small end facing outward for installing the air suspension bearing (2) at both ends. It has an outer conical surface (3011) that matches the conical inner wall (2011). The air suspension bearing (2) is installed in the seat hole (101) of the bearing seat (1). The frustoconical section (301) of the motor shaft (3) is fitted in the inner sleeve hole of the air suspension bearing (2). There is a wedge-shaped gap (4) between its outer conical surface (3011) and the conical inner wall (2011) of the air suspension bearing (2) that can form a flow of air.

2. The dynamic pressure air suspension bearing structure according to claim 1, characterized in that: Multiple spiral blades (5) with equal arc length are provided on the motor shaft (3) outside the air suspension bearing (2) to push airflow into the wedge-shaped gap (4).

3. The dynamic pressure air suspension bearing structure according to claim 2, characterized in that: The outer conical surface (3011) of the frustum section (301) extends outward from the bearing seat (1) to form a conical extension section (302), and the spiral blade (5) is provided on the conical extension section (302).

4. The dynamic pressure air suspension bearing structure according to claim 3, characterized in that: An annular wind-gathering shroud (6) surrounding the motor shaft (3) is provided on the outside of the bearing housing (1), and the spiral blade (5) is located inside the annular wind-gathering shroud (6).

5. The dynamic pressure air suspension bearing structure according to claim 4, characterized in that: The outer surface of the spiral blade (5) is close to the inner wall of the annular wind-gathering cover (6).

6. The dynamic pressure air suspension bearing structure according to claim 5, characterized in that: The inner wall of the annular wind-gathering cover (6) is an arc-shaped guide surface (601) from the outside to the inside, and the inner end of the arc-shaped guide surface (601) is close to the outer end of the conical inner wall (2011) of the air suspension bearing (2).

7. The dynamic pressure air suspension bearing structure according to claim 2, characterized in that: The outer end of the conical inner wall (2011) is connected to a windbreak ring (7) that extends radially outward.

8. A motor employing the dynamic pressure air suspension bearing structure as described in claim 1 or 2, comprising a rotor (1002) mounted on the motor shaft (3), a stator (1003) sleeved around the outer periphery of the rotor (1002), and a motor housing (1001) covering and fixing the stator (1003), wherein the motor housing (1001) has a mounting hole one and a mounting hole two for mounting bearing seats at both ends, characterized in that: One end of the bearing housing (1) is a fixed bearing housing (102) fixed in the first mounting hole, and the other end of the bearing housing (1) is a movable bearing housing (103) that can slide axially at a set distance in the second mounting hole. When the motor shaft (3) is stationary, the movable bearing housing (103) is pushed toward the fixed bearing housing (102), which reduces the wedge gap (4) between the cone sections (301) at both ends of the motor shaft (3) and their respective air suspension bearings (2). When the motor shaft (3) is running, the wedge gap (4) expands under the action of dynamic pressure airflow, which causes the movable bearing housing (103) to retract.

9. The motor according to claim 8, characterized in that: An annular boss (104) is provided on the outer periphery of the movable bearing seat (103) located inside the motor housing (1001). A compression spring (105) is provided between the annular boss (104) and the inner wall of the motor housing (1001) at the edge of the mounting hole. The compression spring (105) provides a force to push the movable bearing seat (103), the motor shaft (3), and the rotor (1002) on the motor shaft (3) together toward the fixed bearing seat (102).

10. The motor according to claim 8, characterized in that: The wedge-shaped gap (4) is located inside the motor housing (1001) with one end of the annular port aligned with the coil end (10031) of the stator coil.

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