Ultrahigh-speed motor rotor structure

Abstract

The utility model discloses an ultra-high-speed motor rotor structure, which comprises a casing, side end covers are assembled on two sides of the casing, a motor stator is coaxially fixed in the casing, a coil winding is arranged on the motor stator, an air bearing is embedded and fixed on the side end covers, a motor rotor is rotatably arranged on the air bearing, and the coil winding is arranged on the motor rotor. The motor rotor and the motor stator are coaxially assembled, an airflow gap is arranged between the motor rotor and the motor stator, a heat dissipation air channel is arranged in the machine shell, and the heat dissipation air channel assists airflow heat dissipation of the motor rotor through the airflow gap; the motor rotor comprises magnetic steel which is of a cylindrical solid structure, a first rotating shaft and a second rotating shaft are arranged on the two sides of the magnetic steel respectively, the end of the first rotating shaft and the end of the second rotating shaft are both connected into the corresponding air bearings, the magnetic steel is sleeved with a magnetic steel sheath, and the magnetic steel sheath is sleeved with a rotor. And the end parts of the rotating shaft I and the rotating shaft II are fixed with the magnetic steel through magnetic steel sheaths.

Description

Technical Field

[0001] The utility model belongs to the technical field of motor rotors, in particular to an ultra-high-speed motor rotor structure. Background Art

[0002] Ultra-high-speed motors usually refer to motors with speeds exceeding 10,000 rpm. Ultra-high-speed motors have high rotor speeds, so the motor sheath magnets will have large deformations at rated speeds, causing the magnets to separate from the shaft and the magnet sheath. The higher the speed, the more obvious the separation, causing greater vibration. When the vibration exceeds a certain level, it will bring various hazards, including noise, material fatigue, rotor instability, shaft fracture and other serious consequences. At the same time, the rotor speed is high, the heat is concentrated, and the heat dissipation demand is large.

[0003] Therefore, it is necessary to provide a rotor structure for an ultra-high-speed motor to solve the problems raised in the above background technology. Utility Model Content

[0004] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: an ultra-high-speed motor rotor structure, comprising: a housing, with side end covers on both sides, a motor stator coaxially fixed inside the housing, a coil winding provided on the motor stator, an air bearing embedded and fixed on the side end cover, a motor rotor rotatably arranged on the air bearing, the motor rotor and the motor stator are coaxially assembled, and an air flow gap is provided between them, a heat dissipation air duct is provided in the housing, and the heat dissipation air duct assists the motor rotor in air flow heat dissipation through the air flow gap;

[0005] The motor rotor comprises: a magnetic steel, which adopts a cylindrical solid structure, a rotating shaft 1 and a rotating shaft 2 are respectively arranged on both sides of the magnetic steel, the ends of the rotating shaft 1 and the rotating shaft 2 are connected to the corresponding air bearings, the magnetic steel outer shell is connected with a magnetic steel sheath, and the ends of the rotating shaft 1 and the rotating shaft 2 are fixed to the magnetic steel through the magnetic steel sheath;

[0006] The magnetic steel and the magnetic steel sleeve are assembled by using interference fit technology, and the rotating shaft 1 and the magnetic steel sleeve are connected and fixed by axial welding, and the rotating shaft 2 and the magnetic steel sleeve are connected and fixed by radial welding;

[0007] The surface of the magnetic steel sheath is provided with rifling, and the rifling is a plurality of riflings distributed in a circle; and the rifling is divided into a quick guide section, a middle section and a tail section in sequence with the rotating shaft 1 as the starting point, the rifling density of the middle section is higher than that of the quick guide section and the tail section, the number of spiral turns of the rifling of the quick guide section and the tail section is 0 to 1, and the middle section is distributed at the position of the magnetic steel of the motor rotor, and its length is greater than the length of the magnetic steel;

[0008] The rifling of the middle section is configured as a normal rifling or a reverse rifling.

[0009] Furthermore, preferably, the rotating shaft 1, the rotating shaft 2 and the magnetic steel are axially compressed in the tooling with a compression force of not less than 500N.

[0010] Furthermore, preferably, a heat-shrink fitting temperature of 200° C. to 300° C. is selected for the assembly of the magnetic steel sheath and the magnetic steel, and a tool press is used.

[0011] Furthermore, as a preference, the two contact surfaces of the rotating shaft 1, the rotating shaft 2 and the magnetic steel are also bonded with magnetic steel glue.

[0012] Furthermore, as a preference, the rifling depth of the quick guide section and the tail section of the magnetic steel sheath ranges from 1.2 mm to 2 mm, and the rifling width is ;

[0013] The width of the rifling in the middle section of the magnetic steel sheath is , and the spacing between adjacent rifling grooves is .

[0014] Furthermore, preferably, the rapid guide section and the tail section of the rifling adopt gradual rifling, and the middle section of the rifling adopts uniform rifling.

[0015] Further, as a preference, a side protrusion is provided on the contact assembly end of the rotating shaft 2 with the magnetic steel sleeve, and a notch is correspondingly provided on the magnetic steel sleeve. The side protrusion is tightly assembled with the notch, so that the rotating shaft 2 is located at the side protrusion and is welded and fixed to the magnetic steel sleeve by a small-range axial welding method.

[0016] Further, as a preference, the contact assembly end of the magnetic steel sheath located at the rotating shaft 1 is also provided with a side protrusion, so that the rotating shaft 1 is welded and fixed to the magnetic steel sheath by a small range radial welding method at the side protrusion;

[0017] The side protrusions on the second rotating shaft and the side protrusions on the magnetic steel sheath are staggered in cross section.

[0018] Compared with the prior art, the beneficial effects of the utility model are:

[0019] The magnetic steel and the magnetic steel sheath in the utility model adopt the interference sleeve process, the structure is stable at ultra-high speed, the deformation of the rotor parts is small, the vibration is small, and the motor runs stably;

[0020] The utility model improves the processing technology of the ultra-high-speed motor rotor structure, greatly reduces the requirements for processing accuracy, and reduces the production cost of the motor;

[0021] The utility model also adopts the method of opening straight rifling on the magnetic steel sheath to enhance the heat dissipation effect on the motor rotor and reduce eddy current loss; in particular, the use of high-density straight rifling in the middle section at the magnetic steel of the motor rotor can effectively dissipate heat in the middle of the rotor, while the fast guide section and tail section at both ends of the rotor facilitate rapid airflow. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the utility model;

[0023] Figure 2 The structure diagram of the rifling line of the utility model is shown in FIG. Figure 1 ;

[0024] Figure 3 The structure diagram of the rifling line of the utility model is shown in FIG. Figure 2 ;

[0025] Figure 4 It is a schematic diagram of the structure of the rapid guide section and the tail section of the gradual rifling in the utility model;

[0026] Figure 5 It is a schematic diagram of the structure of the middle section and equal rifling in the utility model;

[0027] Figure 6 It is a structural schematic diagram of the side protrusion in the utility model;

[0028] Figure 7 This is a schematic diagram of heat distribution during operation of the motor rotor in the utility model;

[0029] In the figure: 1. motor stator; 11. housing; 12. side end cover; 13. air bearing; 2. magnetic steel; 21. shaft 1; 22. shaft 2; 3. rifling; 31. quick guide section; 32. middle section; 33. tail section; 4. side protrusion. DETAILED DESCRIPTION

[0030] See also Figure 1-6 In the embodiment of the utility model, an ultra-high-speed motor rotor structure comprises: a housing 11, both sides of which are equipped with side end covers 12, a motor stator 1 is coaxially fixed inside the housing 11, a coil winding is provided on the motor stator 1, an air bearing 13 is embedded and fixed on the side end cover 12, a motor rotor is rotatably provided on the air bearing 13, the motor rotor is coaxially assembled with the motor stator 1, and an air flow gap is provided therebetween, a heat dissipation air duct is provided inside the housing 11, that is, an air inlet hole and an exhaust hole are opened on the housing to realize internal air flow heat dissipation (belonging to the prior art, no more details are given), and the heat dissipation air duct assists the motor rotor air flow heat dissipation through the air flow gap;

[0031] The motor rotor comprises: a magnetic steel 2, which adopts a cylindrical solid structure, and a rotating shaft 1 21 and a rotating shaft 22 are respectively arranged on both sides of the magnetic steel 2, and the ends of the rotating shaft 1 21 and the rotating shaft 2 22 are connected to the corresponding air bearing 13, and a magnetic steel sleeve 23 is connected to the outer shell of the magnetic steel 2, and the ends of the rotating shaft 1 21 and the rotating shaft 2 22 are fixed to the magnetic steel 2 through the magnetic steel sleeve 23; the magnetic steel, the rotating shaft 1, and the rotating shaft 2 are welded after interference fitting through the magnetic steel sleeve, and the whole is ground to form a rotor as a whole, wherein the magnetic steel adopts a cylindrical solid structure, which is opposite to the tile-like structure horizontally attached to the surface of the rotor shaft, which can effectively prevent the rotor shaft from separating from the magnetic steel and the magnetic steel sleeve at high speed, without considering a series of negative effects caused by high-speed centrifugal force, thereby ensuring that the motor rotor can work normally at high speed;

[0032] The magnetic steel 2 and the magnetic steel sheath 23 are assembled by using interference fit technology, and the rotating shaft 1 21 and the magnetic steel sheath 23 are connected and fixed by axial welding, and the rotating shaft 22 and the magnetic steel sheath 23 are connected and fixed by radial welding; thereby, the stress of the magnetic steel sheath can be offset, ensuring that the motor rotor will not have structural displacement or looseness during rotation, wherein the interference amount selection steps are:

[0033] Step 1: Use professional calculation software to input the peak operating parameters of the motor and calculate the interference fit selected at the motor's maximum speed that will not cause the workpiece to loosen. At the maximum temperature, due to thermal expansion, the interference fit can still meet the working requirements at the highest operating temperature.

[0034] Step 2: The calculation results are further verified by simulation software. The maximum value of the sheath stress at the limiting speed is much smaller than the yield strength of the material, and the sheath deformation is also within the controllable range allowed.

[0035] The surface of the magnetic steel jacket 23 is provided with rifling 3, and the rifling 3 is a plurality of riflings distributed in a circle; and the rifling 3 is divided into a quick guide section 31, a middle section 32 and a tail section 33 in sequence with the rotating shaft 21 as the starting point, and the density of the rifling 3 of the middle section 32 is higher than that of the quick guide section 31 and the tail section 33, and the number of spiral turns of the rifling 3 of the quick guide section 31 and the tail section 33 is 0 to 1 turn (which can be a half turn or a quarter turn, etc.), and the middle section is distributed at the magnetic steel position of the motor rotor, and its length is greater than the magnetic steel length, that is, the middle end of the rifling can mainly assist the airflow to dissipate the airflow at the magnetic steel position in the magnetic steel jacket, and the quick guide section is used to guide the airflow surface to the middle section, at this time, the airflow in the middle section has a large contact area with the magnetic steel jacket, a long flow trajectory, a long residence time, and a significant heat dissipation effect, and the tail section can quickly guide and discharge the airflow after absorbing heat;

[0036] Embodiment 1: The rifling takes the rotating shaft 1 as the starting point. At this time, when the airflow enters the electromagnetic air gap, it passes through the fast guide section 31, the middle section 32 and the tail section 33 in the rifling, forming airflow heat dissipation for the magnetic steel sheath;

[0037] Embodiment 2: The rifling starts from any position between the rotating shaft 1 and the magnetic steel sheath 23 located on the outer side of the motor stator 1. At this time, the airflow can form a swirl before entering the electromagnetic air gap, thereby enhancing the flow diffusion.

[0038] The rifling of the middle section is configured as positive rifling or reverse rifling. When the middle section is configured as reverse rifling, a corresponding air resistance can be formed to slow down the flow of airflow in the electromagnetic air gap. The airflow contacts the surface of the magnetic steel sheath for a long time, and the heat dissipation is more sufficient.

[0039] In this embodiment, the rotating shaft 1 21, the rotating shaft 22 and the magnetic steel 2 are axially compressed with a compression force of not less than 500N in the tooling to improve the tightness of the assembly.

[0040] As a preferred embodiment, the heat-shrink fitting temperature of 200° C. to 300° C. is selected for the assembly of the magnetic steel sheath 23 and the magnetic steel 2, and the tooling is pressed.

[0041] In this embodiment, the two contact surfaces of the rotating shaft 1 21 , the rotating shaft 2 22 and the magnetic steel 2 are also bonded with magnetic steel glue.

[0042] In this embodiment, the depth of the rifling 3 of the quick guide section 31 and the tail section 33 of the magnetic steel sheath 23 ranges from 1.2 mm to 2 mm, and the width of the rifling is , 1.5mm< <2.4mm;

[0043] The width of the rifling 3 in the middle section 32 of the magnetic steel sheath 23 is ,2mm< <2.8mm, and the distance between adjacent rifling grooves is ,8mm< <15mm, so that when the airflow passes through the middle section of the magnetic steel sheath, the contact area with the magnetic steel sheath surface is large, the flow trajectory is long, the residence time is increased, and sufficient heat dissipation of the motor rotor magnetic steel position is achieved.

[0044] In this embodiment, the rapid guide section 31 and the tail section 33 of the rifling 3 adopt gradual rifling. The advantage of gradual rifling is that different curve equations can be used to adjust the size of the force on the rifling guide side to improve the stress condition of the starting part of the rifling and reduce wear. The middle section 32 of the rifling 3 adopts uniform rifling. The advantage of uniform rifling is good processing technology and high processing accuracy.

[0045] As a preferred embodiment, a side protrusion 4 is provided on the contact assembly end of the rotating shaft 22 with the magnetic steel sleeve 23, and a notch is correspondingly provided on the magnetic steel sleeve 23. The side protrusion 4 is tightly assembled with the notch, so that the rotating shaft 22 is located at the side protrusion 4 and is welded and fixed to the magnetic steel sleeve 23 by a small-range axial welding method, thereby providing a small-range axial welding at the radial welding position of the rotating shaft 2 and the magnetic steel sleeve, further realizing the stress offset of the magnetic steel sleeve and improving the assembly effect.

[0046] In this embodiment, the contact assembly end of the magnetic steel sheath 23 located at the rotating shaft 21 is also provided with a side protrusion 4, so that the rotating shaft 21 is located at the side protrusion 4 and is welded and fixed to the magnetic steel sheath 23 by a small range radial welding method;

[0047] The side protrusions 4 on the second rotating shaft 22 and the side protrusions 4 on the magnetic steel sheath 23 are staggered in cross section.

[0048] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An ultra-high-speed motor rotor structure, characterized in that: It includes: A casing (11) is provided with side end covers (12) on both sides thereof, a motor stator (1) is coaxially fixed inside the casing (11), a coil winding is provided on the motor stator (1), an air bearing (13) is embedded and fixed on the side end cover (12), a motor rotor is rotatably provided on the air bearing (13), the motor rotor and the motor stator (1) are coaxially mounted, and an air flow gap is provided between them, a heat dissipation air duct is provided inside the casing (11), and the heat dissipation air duct assists the motor rotor in heat dissipation through the air flow gap; The motor rotor comprises: a magnetic steel (2) which adopts a cylindrical solid structure, a rotating shaft (21) and a rotating shaft (22) are respectively arranged on both sides of the magnetic steel (2), the ends of the rotating shaft (21) and the rotating shaft (22) are both connected to the corresponding air bearing (13), the outer shell of the magnetic steel (2) is connected with a magnetic steel sheath (23), and the ends of the rotating shaft (21) and the rotating shaft (22) are both fixed to the magnetic steel (2) through the magnetic steel sheath (23); The magnetic steel (2) and the magnetic steel sheath (23) are assembled by using an interference fit technology, and the first rotating shaft (21) and the magnetic steel sheath (23) are connected and fixed by an axial welding method, and the second rotating shaft (22) and the magnetic steel sheath (23) are connected and fixed by a radial welding method; The surface of the magnetic steel sheath (23) is provided with rifling (3), and the rifling (3) is a plurality of riflings distributed in a circle; and the rifling (3) is divided into a quick guide section (31), a middle section (32) and a tail section (33) in sequence with the rotating shaft 1 (21) as the starting point; the density of the rifling (3) in the middle section (32) is higher than that in the quick guide section (31) and the tail section (33); the number of spiral turns of the rifling (3) in the quick guide section (31) and the tail section (33) is 0 to 1; the middle section (32) is distributed at the position of the magnetic steel (2) of the motor rotor, and its length is greater than the length of the magnetic steel (2); The rifling of the middle section (32) is configured as a normal rifling or a reverse rifling.

2. The ultra-high-speed motor rotor structure according to claim 1, characterized in that: The rotating shaft 1 (21), the rotating shaft 2 (22) and the magnetic steel (2) are axially compressed in the tooling with a compression force of not less than 500N.

3. The ultra-high-speed motor rotor structure according to claim 1, characterized in that: During the assembly of the magnetic steel sheath (23) and the magnetic steel (2), a heat-shrink temperature of 200°C to 300°C is selected, and tooling is used for press-fitting.

4. The ultra-high-speed motor rotor structure according to claim 2, characterized in that: The two contact surfaces of the rotating shaft 1 (21), the rotating shaft 2 (22) and the magnetic steel (2) are also bonded with magnetic steel glue.

5. The ultra-high-speed motor rotor structure according to claim 1, characterized in that: The depth of the rifling (3) of the quick guide section (31) and the tail section (33) on the magnetic steel sheath (23) ranges from 1.2 mm to 2 mm, and the width of the rifling is ; The width of the rifling (3) of the middle section (32) of the magnetic steel sheath (23) is , and the spacing between adjacent rifling grooves (3) is .

6. The ultra-high-speed motor rotor structure according to claim 1, characterized in that: The rapid guide section (31) and the tail section (33) of the rifling (3) adopt gradual rifling, and the middle section (32) of the rifling (3) adopts uniform rifling.

7. The ultra-high-speed motor rotor structure according to claim 1, characterized in that: A side protrusion (4) is provided on the second rotating shaft (22) at the end in contact with the magnetic steel sleeve (23), and a notch is correspondingly provided on the magnetic steel sleeve (23). The side protrusion (4) is tightly fitted with the notch, so that the second rotating shaft (22) is located at the side protrusion (4) and is welded and fixed to the magnetic steel sleeve (23) by a small-range axial welding method.

8. The ultra-high-speed motor rotor structure according to claim 7, characterized in that: The contact assembly end of the magnetic steel sheath (23) located on the rotating shaft (21) is also provided with a side protrusion (4), so that the rotating shaft (21) is welded and fixed to the magnetic steel sheath (23) at the side protrusion (4) by a small range radial welding method; The side protrusions (4) on the second rotating shaft (22) and the side protrusions (4) on the magnetic steel sheath (23) are staggered in cross section.

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