A magnetic steel omnidirectional cooling type flux switching permanent magnet wheel hub motor

Abstract

This invention discloses an omnidirectional cooling flux-switching permanent magnet hub motor with magnetic steel, comprising three main parts arranged radially: a rotor module, an oil-separated air gap sleeve, and a stator module. The outer shell includes a cylindrical housing and end caps on both sides; a central shaft axially supports and connects to the end caps; the rotor module is mounted on the shaft; the stator module is arranged close to the inner circumference of the housing; permanent magnets are inserted into the stator module; an air gap is formed between the stator and rotor modules; the oil-separated air gap sleeve is fitted into the air gap close to the tooth ends of the stator module and is coaxial with the central shaft; and oil passage holes are provided on the outer shell. In this invention, the stator windings and permanent magnets are concentrated on the stator module, enabling integrated centralized cooling and solving the problem of difficult permanent magnet cooling in traditional permanent magnet motors. Due to the presence of the oil-separated air gap sleeve, the cooling oil flow is restricted to the stator section, preventing it from entering the air gap and thus eliminating oil churning losses.

Description

Technical Field

[0001] This invention relates to the field of electric motors, and in particular to a permanent magnet hub motor with omnidirectional cooling of magnets and flux switching. Background Technology

[0002] In recent years, with the rapid depletion of non-renewable energy sources such as coal and oil, and the resulting ecological and environmental problems, pollution-free and low-noise new energy electric vehicles have gradually replaced internal combustion engine vehicles, becoming a new choice in the transportation sector and experiencing rapid development. Regarding the drive motors for electric vehicles, permanent magnet hub motors have become a popular choice due to their high reliability, high power density, and high efficiency.

[0003] However, due to electromagnetic losses, the operation of permanent magnet motors is accompanied by an increase in temperature. Excessive temperature accelerates the aging of insulation materials and causes irreversible demagnetization of the permanent magnets, greatly shortening the motor's lifespan. Furthermore, as the most temperature-sensitive component, the permanent magnet is usually located on the rotor, making it difficult to effectively cool using traditional cooling methods.

[0004] Furthermore, since the hub motor is placed directly inside the narrow space of the wheel, the heat source density is high and the heat dissipation conditions are poor, which further exacerbates this problem. Permanent magnet hub motors urgently need to solve the technical challenge of efficient heat dissipation. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a flux-switching permanent magnet hub motor with omnidirectional cooling of the magnet. By improving the structure of the flux-switching permanent magnet hub motor, the heat dissipation effect is improved, the oil churning loss is eliminated, and the motor performance is improved.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A flux-switching permanent magnet hub motor with omnidirectional cooling of magnets includes:

[0008] The outer casing includes a cylindrical shell and end caps located on both sides of the shell;

[0009] The central shaft is axially supported and connected to the end caps on both sides.

[0010] Rotor module, fitted onto a shaft or housing;

[0011] The stator module is arranged close to the inner circumference of the housing or the outer circumference of the shaft;

[0012] Permanent magnets are inserted and arranged in the stator module;

[0013] An air gap is formed between the stator module and the rotor module;

[0014] The oil-separating air gap sleeve is fitted tightly against the tooth ends of the stator module in the air gap and is coaxial with the central shaft;

[0015] The oil-separating air gap sleeve is fixed to the outer casing at both ends;

[0016] The inner circumference of the shell is evenly provided with several continuous grooves;

[0017] The radial length of the permanent magnet is less than the radial length of the stator module. Cavities are formed between the outer circumference of the permanent magnet and the inner circumference of the housing, and between the inner circumference of the permanent magnet and the outer circumference of the oil-separating air gap sleeve.

[0018] Oil passage holes are provided on the outer casing.

[0019] Furthermore, the stator module includes multiple U-shaped stators, which are arranged equidistantly around the inner circumference of the housing, with permanent magnets tightly clamped in the gaps between adjacent U-shaped stators.

[0020] Furthermore, the U-shaped stator has internal toothed slots, and the stator windings are wound in the internal toothed slots and placed coaxially with the central shaft.

[0021] Furthermore, the stator windings use centralized or distributed coils, eliminating the need for potting.

[0022] Furthermore, the U-shaped stator has a stator yoke that fits tightly against the inner circumference of the housing, with beveled angles on both sides of the stator yoke.

[0023] Furthermore, multiple axial through holes are evenly provided on both sides of the permanent magnet.

[0024] Furthermore, the rotor module adopts a salient pole structure, which includes multiple elongated teeth evenly arranged along the circumference.

[0025] Furthermore, the oil passage is an axial oil passage in the outer casing, which includes an axial oil inlet passage and an axial oil outlet passage. The axial oil inlet passage is opened on the top of one end cover, and the axial oil outlet passage is correspondingly opened on the top of the other end cover.

[0026] Furthermore, the oil passage is a radial oil passage in the outer casing, which includes a radial oil inlet passage and a radial oil outlet passage, and the radial oil inlet passage and the radial oil outlet passage are symmetrically opened on both sides of the top of the casing.

[0027] The present invention has the following beneficial effects:

[0028] 1. The stator winding and permanent magnet of the present invention are concentrated on the stator module, which can be integrated and centrally cooled, solving the problem of difficult cooling of permanent magnet in traditional permanent magnet motors; due to the presence of the oil-separated air gap sleeve, the cooling oil can be restricted to flow in the stator part and the cooling oil is prevented from entering the air gap, so there will be no oil churning loss.

[0029] 2. The rotor module of the motor has no other parts, resulting in high mechanical strength and more relaxed temperature restrictions, which greatly improves the reliability of the motor under high-speed conditions.

[0030] 3. The special structural design of the stator module can reduce magnetic leakage, save magnet materials, and achieve omnidirectional direct cooling of the magnets, further reducing the temperature rise of the magnets.

[0031] 4. Compared with traditional surface-mount permanent magnet motors, it has stronger magnetization ability and higher air gap magnetic flux density in principle, which is conducive to further improving motor performance. Attached Figure Description

[0032] Figure 1 This is a cross-sectional view of the structure of a permanent magnet hub motor with omnidirectional cooling of magnet steel and internal rotor flux switching according to the present invention.

[0033] Figure 2 This is a partially enlarged view of the stator module of a flux-switching permanent magnet hub motor with omnidirectional cooling of magnets according to the present invention.

[0034] Figure 3 This is a structural cross-sectional view of a permanent magnet hub motor with omnidirectional cooling of magnet steel and external rotor flux switching according to the present invention.

[0035] Figure 4 This is one method of cooling oil flow circulation in an embodiment of the present invention.

[0036] Figure 5 This is another cooling oil flow circulation method in an embodiment of the present invention.

[0037] Figure 6 This is a schematic diagram of the motor flux switching principle in an embodiment of the present invention.

[0038] Among them are: 10, outer shell; 15, continuous slot; 16, axial oil passage hole of outer shell; 17, radial oil passage hole of outer shell; 20, stator module; 21, stator yoke cavity; 22, stator tooth cavity; 23, bevel; 24, axial through hole; 30, permanent magnet; 35, stator slot; 40, oil-separating air gap sleeve; 50, rotor module; 60, central shaft. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to the accompanying drawings and specific preferred embodiments.

[0040] In the description of this invention, it should be understood that the terms "left side," "right side," "upper part," "lower part," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. "First," "second," etc., do not indicate the importance of the components, and therefore should not be construed as a limitation of this invention. The specific dimensions used in this embodiment are only for illustrating the technical solution and do not limit the scope of protection of this invention.

[0041] like Figure 1 As shown, a flux-switching permanent magnet hub motor with omnidirectional cooling of magnets comprises three main parts: a rotor module, an oil-separated air gap sleeve, and a stator module placed radially, as detailed below:

[0042] The outer casing 10 includes a cylindrical shell and end caps located on both sides of the shell; as shown... Figure 3 As shown, the cylindrical shell is arranged horizontally, with end caps on both sides of the cylindrical shell. The shell has sufficient cavities, and each module is housed within the cavity.

[0043] The central shaft 60 is axially supported and connected to the end caps on both sides.

[0044] Furthermore, the two ends of the central shaft 60 are supported and connected to the end caps on both sides by bearings.

[0045] Rotor module 50 is mounted on central shaft 60.

[0046] The rotor module adopts a salient pole structure, without permanent magnets or excitation windings, and consists of multiple elongated teeth evenly arranged along its circumference. With no other components on the rotor module, the motor boasts high mechanical strength and more relaxed temperature limitations, significantly improving its reliability under high-speed conditions.

[0047] In some embodiments of this application, the elongated teeth of the rotor module 50 are rectangular or trapezoidal in shape; obviously, other salient pole shapes are also applicable.

[0048] Stator module 20 is arranged close to the inner circumference of the housing.

[0049] Furthermore, the stator module 20 includes multiple U-shaped stators, which are arranged equidistantly along the inner circumference of the housing, such as... Figure 1 As shown, there is a certain gap between adjacent U-shaped stators.

[0050] Furthermore, such as Figure 2 As shown, the slot width a of the U-shaped stator and the salient pole tooth width b of the rotor module are equal.

[0051] Permanent magnets 30 are inserted into stator modules 20. The permanent magnets are inserted in the intervals of the stator modules and are alternately magnetized tangentially, that is, the polarities of adjacent permanent magnets are opposite.

[0052] Furthermore, such as Figure 1 As shown, the permanent magnet 30 is tightly sandwiched in the gap between adjacent U-shaped stators.

[0053] In some embodiments of this application, the permanent magnet 30 is rectangular in shape; obviously, other shapes are also applicable.

[0054] Furthermore, the U-shaped stator has internal toothed grooves, such as... Figure 1 As shown, the stator winding is wound in the internal tooth slot and placed coaxially with the central shaft 60.

[0055] In some embodiments of this application, the stator winding uses centralized or distributed coils, which do not require potting, allowing cooling oil to enter the stator slot 35 to directly cool the stator winding.

[0056] Furthermore, such as Figure 1 , 3 As shown in Figures 4-5, a cylindrical air gap is formed between the stator module 20 and the rotor module 50.

[0057] The oil-separating air gap sleeve 40 is fitted into the air gap, closely attached to the tooth ends of the stator module 20, and is coaxial with the central shaft 60; both ends of the oil-separating air gap sleeve are fixed to the outer casing 10. The oil-separating air gap sleeve can restrict the flow of cooling oil in the stator part and prevent cooling oil from entering the air gap, thus preventing oil churning loss.

[0058] like Figure 1 , 3 As shown, there is still a certain gap between the oil-separating air gap sleeve and the rotor module 50 to facilitate the rotation of the rotor module.

[0059] like Figure 1-2 As shown, the U-shaped stator has a stator yoke that fits tightly against the inner circumference of the housing, and the stator yoke has bevels of 23 on both sides to reduce magnetic leakage.

[0060] Furthermore, several elongated channels 15 are evenly provided on the inner circumference of the housing to allow cooling oil to circulate, thereby cooling the stator yoke.

[0061] Furthermore, the radial length of the permanent magnet is less than the radial length of the stator module. Cavities are formed between the outer circumference of the permanent magnet and the inner circumference of the housing, and between the inner circumference of the permanent magnet and the outer circumference of the oil-separating air gap sleeve. This arrangement not only reduces the amount of material used for the permanent magnet, but also leaves cavities at both the top and bottom ends for cooling oil to flow through, thereby cooling the upper and lower end faces of the permanent magnet.

[0062] Specifically, such as Figure 1-2As shown, along the radial direction, the radial length of the permanent magnet 30 is less than the radial length of the U-shaped stator. A stator yoke cavity 21 is formed between the outer circumferential surface of the permanent magnet and the inner circumference of the shell, and a stator tooth cavity 22 is formed between the inner circumferential surface of the permanent magnet and the outer circumference of the oil-separating air gap sleeve.

[0063] Furthermore, such as Figure 3-4 As shown, the axial length of the stator module 20 is the same as the axial length of the rotor module 50, and both are less than the axial length of the housing.

[0064] Furthermore, multiple axial through holes 24 are staggered on both sides of the permanent magnet, such as... Figure 1-2 As shown, the permanent magnets are tightly clamped between adjacent U-shaped stators, and cooling oil flows through the axial through-holes to cool the two sides of the permanent magnets clamped between adjacent U-shaped stators.

[0065] In some embodiments of this application, both the stator module and the rotor module can be formed by stamping silicon steel sheets.

[0066] In some embodiments of this application, the permanent magnets are alternately magnetized tangentially.

[0067] In some embodiments of this application, the material of the oil-separating air gap sleeve can be non-magnetic and high-strength materials such as carbon fiber, glass fiber, and stainless steel, to ensure the distribution of the air gap magnetic field.

[0068] Furthermore, the outer casing 10 is provided with an oil passage hole for oil inlet and outlet, as well as for the circulation of cooling oil.

[0069] In addition, such as Figure 3 As shown, this embodiment also provides an external rotor flux-switching permanent magnet hub motor with omnidirectional cooling of magnets. The rotor module 50 is housed inside the outer casing 10, and the stator module 20 is arranged close to the outer circumference of the central shaft 60. The remaining arrangement is the same as that of the internal rotor motor.

[0070] Furthermore, since the outer casing rotates together with the rotor, no additional oil passages are provided on the outer casing.

[0071] The following uses an internal rotor motor as an example to provide two methods for opening oil passages, forming a cooling oil flow circulation, and in conjunction with the attached... Figure 4-5 Further details regarding this application:

[0072] like Figure 4 and Figure 5 As shown in the figure, solid arrows represent flows visible on the cross-sectional plane, while dashed arrows represent flows not visible on the cross-sectional plane.

[0073] like Figure 4As shown, the oil passage is an axial oil passage in the outer casing. The axial oil passage 16 includes an axial oil inlet passage and an axial oil outlet passage. The axial oil inlet passage is opened on the top of one end cover, and the axial oil outlet passage is correspondingly opened on the top of the other end cover.

[0074] Figure 4 In the design, the axial oil inlet and outlet holes correspond to each other and are at the same height. Cooling oil enters axially through the axial oil inlet hole above one end cover, then flows through the housing through-slot 15, the stator yoke cavity 21, the stator tooth cavity 22, the permanent magnet axial through-hole 24, and the stator slot 35, respectively, and finally converges and exits through the axial oil outlet hole on the other side. After external cooling, it re-enters the motor, completing the oil circulation. Both the axial oil inlet and outlet holes are located at the top, utilizing gravity to ensure that the cooling oil fully fills the entire stator chamber, resulting in better heat dissipation.

[0075] like Figure 5 As shown, the oil passage is a radial oil passage in the outer casing. The radial oil passage 17 of the outer casing includes a radial oil inlet passage and a radial oil outlet passage, which are symmetrically opened on both sides of the top of the casing.

[0076] Figure 5 In the process, cooling oil enters radially through the radial oil inlet hole at the top of the outer casing 10, and then flows through the elongated channel 15, the stator yoke cavity 21, the stator tooth cavity 22, the permanent magnet axial through hole 24, and the stator slot 35 respectively. Finally, it converges and exits through the radial oil outlet hole on the other side. After external cooling, it re-enters the motor, completing the oil flow circulation. Similarly, both the radial oil inlet hole and the radial oil outlet hole are located at the top of the outer casing 10, using gravity to ensure that the cooling oil fully fills the entire stator cavity, resulting in better heat dissipation.

[0077] In some embodiments of this application, the magnetic flux switching principle of the motor is as follows: Figure 5 As shown, in principle, it has a stronger magnetic focusing ability and a higher air gap magnetic flux density, which is beneficial to further improve the performance of the motor.

[0078] When the rotor module is located Figure 6 In position (a), the two adjacent elongated teeth of the rotor module are respectively opposite to the left teeth of the two adjacent U-shaped stators. The permanent magnet flux generated by the magnet passes through the stator yoke and enters the elongated teeth of the rotor module from the stator winding into the air gap. At this time, the magnetic flux amplitude in the stator winding coil is the maximum polarity value.

[0079] When the rotor module moves to Figure 6 In position (b), one of the elongated teeth of the rotor module is opposite to the slot of the U-shaped stator, and the effective magnetic flux in the stator winding coil is 0.

[0080] When the rotor module moves to Figure 6 In position (c), the two adjacent elongated teeth of the rotor module are respectively opposite to the right teeth of the two adjacent U-shaped stators. The permanent magnet flux generated by the magnet passes through the stator yoke and enters the air gap and the elongated teeth of the rotor module, and then passes through the air gap into the stator winding. At this time, the magnetic flux amplitude in the stator winding coil is the maximum polarity, and the direction is the same as the polarity. Figure 6 (a) On the contrary.

[0081] As described above, the magnetic circuit design causes the permanent magnet flux of the stator winding chain to change periodically between positive and negative maximum values ​​when the rotor module moves continuously, and the magnetic concentration ability is stronger, which can increase the air gap magnetic flux density.

[0082] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0083] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.

Claims

1. A flux-switching permanent magnet hub motor with omnidirectional cooling of magnets, characterized in that: include: The outer casing includes a cylindrical shell and end caps located on both sides of the shell; The central shaft is axially supported and connected to the end caps on both sides. The rotor module is fitted onto the central shaft or the outer casing; The stator module is arranged close to the inner circumference of the housing or the outer circumference of the shaft; Permanent magnets are inserted and arranged in the stator module; An air gap is formed between the stator module and the rotor module; The oil-separating air gap sleeve is fitted tightly against the tooth ends of the stator module in the air gap and is coaxial with the central shaft; The oil-separating air gap sleeve is fixed to the outer casing at both ends; The inner circumference of the shell is evenly provided with several continuous grooves; The radial length of the permanent magnet is less than the radial length of the stator module. Cavities are formed between the outer circumference of the permanent magnet and the inner circumference of the housing, and between the inner circumference of the permanent magnet and the outer circumference of the oil-separating air gap sleeve. Oil passage holes are provided on the outer casing.

2. The omnidirectional cooling type flux-switching permanent magnet hub motor according to claim 1, characterized in that: The stator module includes multiple U-shaped stators, which are arranged equidistantly around the inner circumference of the housing, with permanent magnets tightly clamped in the gaps between adjacent U-shaped stators.

3. The omnidirectional cooling type flux-switching permanent magnet hub motor according to claim 2, characterized in that: The U-shaped stator has internal toothed slots, and the stator windings are wound in the internal toothed slots and placed coaxially with the central shaft.

4. The omnidirectional cooling type flux-switching permanent magnet hub motor according to claim 3, characterized in that: The stator windings use centralized or distributed coils and do not require potting.

5. The omnidirectional cooling type flux-switching permanent magnet hub motor according to claim 2, characterized in that: The U-shaped stator has a stator yoke that fits tightly against the inner circumference of the housing, with beveled angles on both sides of the stator yoke.

6. The omnidirectional cooling type flux-switching permanent magnet hub motor according to claim 2, characterized in that: Multiple axial through holes are evenly distributed on both sides of the permanent magnet.

7. The omnidirectional cooling type flux-switching permanent magnet hub motor according to claim 1, characterized in that: The rotor module adopts a salient pole structure, which includes multiple elongated teeth evenly arranged along the circumference.

8. The omnidirectional cooling type flux-switching permanent magnet hub motor according to claim 1, characterized in that: The oil passage is an axial oil passage for the outer casing. The axial oil passage for the outer casing includes an axial oil inlet passage and an axial oil outlet passage. The axial oil inlet passage is opened on the top of one end cover, and the axial oil outlet passage is opened on the top of the other end cover.

9. The omnidirectional cooling type flux-switching permanent magnet hub motor according to claim 1, characterized in that: The oil passage is a radial oil passage in the outer casing, which includes a radial oil inlet passage and a radial oil outlet passage. The radial oil inlet passage and the radial oil outlet passage are symmetrically opened on both sides of the top of the casing.

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