Axial flux motor with tangential magnetic shoe structure

Abstract

The utility model discloses an axial magnetic flux motor with a tangential magnetic shoe structure, which comprises a front end cover, a rear end cover, a rotating shaft, a rotor assembly and a stator core with a winding, a cavity is formed between the front end cover and the rear end cover, the stator core with the winding and the rotor assembly are arranged in the cavity, the rotating shaft is arranged on the rotor assembly, and the tangential magnetic shoe structure is arranged on the rotating shaft. The stator iron core with the winding is located above the rotor assembly to form axial magnetic coupling, the rotor assembly comprises the rotor iron core and a plurality of magnetic shoes, the tangential magnetizing magnetic shoes have a magnetic gathering effect, leakage flux of the tangential magnetizing magnetic shoes can be introduced to the magnetic conductive sheets, and due to the fact that the positions of the magnetic conductive sheets are relatively fixed, the leakage flux cannot enter the end cover. Due to the fact that the resistance of the magnetic conductive sheet is large, the generated eddy current is small, the motor efficiency is guaranteed, the leakage flux is guided into the magnetic conductive sheet, the temperature of the end cover is reduced, and the stability of a motor system is further improved.

Description

Technical Field

[0001] The utility model relates to an axial flux motor with a tangential magnetic tile structure. Background Art

[0002] In the conventional design of axial flux motors (i.e. disc motors), the disc motors with surface mounted magnetic tiles do not have obvious eddy current loss problems, but their power density is not as good as the axial flux motors with tangential magnetic tiles (see the utility model patent with the patent name: A disc motor with high torque density, patent number: 202211420954.9). The magnetic tile structure of the axial flux motor with tangential magnetic tiles has the function of concentrating magnetic flux and increasing power density, but it also causes some leakage magnetic flux on the non-air gap side, which has the following defects:

[0003] 1. In the existing axial flux motor with tangential magnetic tile structure, when the fully enclosed structure is adopted, although the tangential magnetic tile can enhance the main magnetic flux (i.e., the magnetic field concentration effect), there will be a small amount of leakage magnetic flux on the non-air gap surface. If the rear end cover is made of conductive materials such as aluminum end cover, the magnetic flux lines of this part of the leakage magnetic flux will be cut, forming eddy currents on the surface and reducing efficiency; see Figure 1 Magnetic circuit diagram shown.

[0004] 2. In a fully enclosed architecture, in order to increase the level of protection, the end covers are often completely enclosed, with as few or no holes as possible. A larger relative area means a smaller equivalent resistance, which results in greater losses caused by eddy currents. The conventional solution is often to keep these non-rotating structures (rear end covers) away from the rotor, but the size of the motor is limited and cannot be increased indefinitely. When the size of the motor increases, the cost increases significantly, which is not cost-effective. In addition, there are often requirements for the installation space of the motor, and there are limitations to reducing eddy current losses by increasing the distance.

[0005] 3. When there is a large eddy current loss on the end cover, the temperature rise of the end cover will be more obvious, affecting the life of the bearing installed in the end cover. The heat will also affect the components that cooperate with or are close to the end cover. Abnormally large eddy current loss and temperature rise may even cause the risk of irreversible demagnetization of the magnetic tile at high temperature. Summary of the invention

[0006] The purpose of the utility model is to provide an axial flux motor with a tangential magnetic tile structure, so as to solve the technical problem in the prior art that the leakage magnetic flux of the axial flux motor with a tangential magnetic tile structure passes through the metal rear end cover, forms eddy currents in the metal rear end cover, causes the motor efficiency to be reduced, and the bearing temperature rise to be high.

[0007] The technical solution of the utility model is implemented as follows: an axial flux motor with a tangential magnetic tile structure, including a front end cover, a rear end cover, a rotating shaft, a rotor assembly and a stator core with windings, a cavity is formed between the front end cover and the rear end cover, the stator core with windings and the rotor assembly are installed in the cavity, the rotating shaft is installed on the rotor assembly, the stator core with windings is located above the rotor assembly to form axial magnetic coupling, the rotor assembly includes a rotor core, a plurality of magnetic tiles and, the rotor core is installed on the rotating shaft, a plurality of magnetic tiles are circumferentially arranged on the rotor core, a plurality of magnetic tiles include tangentially magnetized magnetic tiles, a magnetic conductive sheet is also provided in the cavity, the magnetic conductive sheet is detachably installed on the rear end cover, the leakage magnetic flux of the rotor assembly will be introduced into the magnetic conductive sheet, so that the leakage magnetic flux cannot enter the rear end cover to form eddy currents.

[0008] Furthermore, the plurality of magnetic tiles are composed of axially magnetized magnetic tiles and tangentially magnetized magnetic tiles.

[0009] Furthermore, the magnetic tile is made of neodymium iron boron or ferrite.

[0010] Furthermore, the magnetic conductive sheet is made of a magnetic conductive material with a relatively large resistivity.

[0011] Furthermore, the magnetic conductive sheet is made of silicon steel sheet.

[0012] Furthermore, the magnetic conductive sheet can be fixed to the rear end cover by bonding, or by screws or rivets.

[0013] Furthermore, the thickness of the magnetic conductive sheet is in the range of 0.15 mm to 0.8 mm.

[0014] Furthermore, the thickness of the magnetic conductive sheet is 0.5 mm.

[0015] Compared with the prior art, the utility model has the following advantages:

[0016] Effect 1: The tangentially magnetized magnetic tiles of the utility model have a magnetic field gathering effect, which improves the power density of the motor, and the leakage magnetic flux of the tangentially magnetized magnetic tiles will be introduced into the magnetic conductive sheet. Since the position of the magnetic conductive sheet is relatively fixed, the leakage magnetic flux will not enter the end cover, so no eddy current will be formed on the end cover, and the motor efficiency can be improved.

[0017] Effect 2: Due to the large resistance of the magnetic conductive sheet, the eddy current that can be generated on the magnetic conductive sheet is very small, the motor efficiency is guaranteed, and the leakage magnetic flux is guided into the magnetic conductive sheet. No eddy current will be formed on the end cover, thereby reducing the operating temperature of the rear end cover, extending the service life of the bearing installed on the rear end cover, and further improving the stability of the motor system.

[0018] Effect 3: The magnetic sheet can be fixed in various ways, which can be selected according to actual needs to meet various usage scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the magnetic circuit of an existing axial flux motor with a tangential magnetic tile structure;

[0020] Figure 2 A stereogram provided for the utility model;

[0021] Figure 3 An exploded schematic diagram provided for the utility model;

[0022] Figure 4 A top view provided for the utility model;

[0023] Figure 5 for Figure 4 Schematic diagram of the cross-sectional structure of the middle BB;

[0024] Figure 6 A schematic diagram of the tangential magnetic tile structure provided by the utility model;

[0025] Figure 7 This is the equivalent magnetic circuit diagram after adding the magnetic conductive sheet provided by the utility model. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0027] like Figures 2 to 7As shown, this embodiment provides: an axial flux motor with a tangential magnetic tile structure, including a front cover 1, a rear cover 2, a rotating shaft 3, a rotor assembly 4 and a stator core 5 with a winding, a cavity 10 is formed between the front cover 1 and the rear cover 2, the stator core 5 with the winding and the rotor assembly 4 are installed in the cavity 10, the rotating shaft 3 is installed on the rotor assembly 4, the stator core 5 with the winding is located above the rotor assembly 4 to form an axial magnetic coupling, the rotor assembly 4 includes a rotor core 41, a plurality of magnetic tiles 42 and, the rotor core 41 is installed on the rotating shaft 3, a plurality of magnetic tiles 42 are arranged on the rotor core 41 at intervals in the circumferential direction, and a plurality of magnetic tiles 42 include tangentially magnetized magnetic tiles 42b, characterized in that: a magnetic conductive sheet 6 is also provided in the cavity 10, the magnetic conductive sheet 6 is detachably installed on the rear cover 2, and the leakage magnetic flux of the rotor assembly 4 will be introduced into the magnetic conductive sheet 6, so that the leakage magnetic flux cannot enter the rear cover 2 and form eddy currents. In order to reduce eddy current loss, the magnetic conductive sheet 6 with high resistivity guides the leakage magnetic flux into the magnetic conductive sheet 6, so that the eddy current loss on the end cover is greatly reduced, the efficiency is improved, and the temperature rise is improved. The eddy current and hysteresis losses of the magnetic conductive sheet 6 with high resistivity in the magnetic field are at normal levels, and the structure is simple, which is easy to process and install; when using the magnetic conductive material, the magnetic conductive sheet cannot be set too thick, on the one hand, for cost considerations, on the other hand, since the leakage magnetic flux itself is not much, the thinner material can fully bear it, and too thick may have a counter-effect on the performance.

[0028] Furthermore, the plurality of magnetic tiles 42 are composed of axial magnetized magnetic tiles 42a and tangential magnetized magnetic tiles 42b. The tangential magnetized magnetic tiles can enhance the main magnetic circuit.

[0029] Furthermore, the magnetic tile 42 is made of neodymium iron boron or ferrite. The material of the magnetic tile 42 of the utility model is neodymium iron boron.

[0030] Furthermore, the magnetic conductive sheet 6 is made of a magnetic conductive material with a relatively large resistivity. The magnetic conductive sheet with a relatively large resistivity can block the leakage magnetic flux, so that the leakage magnetic flux cannot enter the end cover.

[0031] Furthermore, the magnetic conductive sheet 6 is made of silicon steel sheet. The magnetic conductive sheet 6 of the utility model is made of silicon steel sheet.

[0032] Furthermore, the magnetic conductive sheet 6 can be fixed to the rear end cover 2 by bonding, or by screws or rivets. The magnetic conductive sheet 6 of the utility model is fixed to the rear end cover 2 by bonding.

[0033] The thickness of the magnetic conductive sheet 6 is in the range of 0.15mm to 0.8mm. The thickness of the magnetic conductive sheet 6 is preferably 0.5mm. The main function of the magnetic conductive sheet 6 of the present patent application is to conduct magnetism. In order to reduce eddy current loss, the magnetic conductive sheet 6 with a large resistivity guides the leakage magnetic flux into the magnetic conductive sheet 6, so that the eddy current loss on the end cover is greatly reduced, the efficiency is improved, and the temperature rise is improved. The magnetic conductive sheet 6 of the present application takes the magnetic flux path of the leakage magnetic flux instead of the main magnetic flux path. Since the magnetic flux of the leakage magnetic flux is relatively small, the thickness of the magnetic conductive sheet 6 cannot be too large, and the range of 0.15mm to 0.8mm is more appropriate. A magnetic conductive sheet with too large thickness will become a condensed magnetic flux, which is not suitable.

[0034] The following are the calculation data of the utility model:

[0035] The resistance of any material can be calculated using the following formula:

[0036]

[0037] ρ represents its resistivity, l represents its equivalent length, and S represents its equivalent area.

[0038] When the conditions such as leakage magnetic field and main structure are constant, the eddy current loss can be expressed as:

[0039]

[0040] When the motor directly uses aluminum end covers, the magnetic circuit diagram is as follows Figure 7 As shown, due to the small resistivity of aluminum and the need for structural strength, the thickness of the aluminum end cap (equivalent to area S) must be certain, and its resistance is very small, resulting in its loss P loss Very big.

[0041] But after adopting the magnetic conductive structure, the magnetic circuit diagram is as follows Figure 7 As shown in the figure, taking silicon steel sheet as an example, the resistivity of silicon steel sheet is very large, and as an auxiliary structure, silicon steel sheet does not play a structural support role, it can be very thin (equivalent to S is very small), and its equivalent resistance will be very large. When other conditions remain unchanged, the equivalent voltage U remains unchanged, and R increases significantly, resulting in this part of the loss P after adding silicon steel sheet. loss Will drop sharply.

[0042] Taking a specific motor as an example, the total loss of the motor end cover and casing before adding silicon steel sheets is compared with the total loss of the silicon steel sheets, end cover and casing after adding silicon steel sheets. The loss of this part is reduced by 86.7%. See the control experimental results in Table 1.

[0043] measure Loss / W Before improvement none 26.9 After improvement Magnetic conductive silicon steel sheet 3.6

[0044] Table 1

[0045] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited thereto. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention are equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An axial flux motor with a tangential magnetic tile structure, comprising a front end cover (1), a rear end cover (2), a rotating shaft (3), a rotor assembly (4) and a stator core (5) with a winding, wherein a cavity (10) is formed between the front end cover (1) and the rear end cover (2), the stator core (5) with the winding and the rotor assembly (4) are installed in the cavity (10), the rotating shaft (3) is installed on the rotor assembly (4), the stator core (5) with the winding is located above the rotor assembly (4) to form an axial magnetic coupling, the rotor assembly (4) comprises a rotor core (41) and a plurality of magnetic tiles (42), the rotor core (41) is installed on the rotating shaft (3), the plurality of magnetic tiles (42) are circumferentially spaced and arranged on the rotor core (41), the plurality of magnetic tiles (42) include tangentially magnetized magnetic tiles (42b), and is characterized in that: A magnetic conductive sheet (6) is also provided in the cavity (10). The magnetic conductive sheet (6) is detachably mounted on the rear end cover (2). The leakage magnetic flux of the rotor assembly (4) is introduced into the magnetic conductive sheet (6), so that the leakage magnetic flux cannot enter the rear end cover (2) and form an eddy current.

2. The axial flux motor with a tangential magnetic tile structure according to claim 1, characterized in that: The plurality of magnetic tiles (42) are composed of axially magnetized magnetic tiles (42a) and tangentially magnetized magnetic tiles (42b).

3. The axial flux motor with a tangential magnetic tile structure according to claim 2, characterized in that: The magnetic tile (42) is made of neodymium iron boron or ferrite.

4. An axial flux motor with a tangential magnetic tile structure according to claim 1, 2 or 3, characterized in that: The magnetic conductive sheet (6) is made of magnetic conductive material.

5. The axial flux motor with a tangential magnetic tile structure according to claim 4, characterized in that: The magnetic conductive sheet (6) is made of silicon steel sheet.

6. An axial flux motor with a tangential magnetic tile structure according to claim 1, 2 or 3, characterized in that: The magnetic conductive sheet (6) can be fixed to the rear end cover (2) by bonding, or fixed to the rear end cover (2) by screws or rivets.

7. An axial flux motor with a tangential magnetic tile structure according to claim 1, 2 or 3, characterized in that: The thickness of the magnetic conductive sheet (6) is in the range of 0.15 mm to 0.8 mm.

8. The axial flux motor with a tangential magnetic tile structure according to claim 7, characterized in that: The thickness of the magnetic conductive sheet (6) is 0.5 mm.

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