Resolver, device having resolver, and electric drive device

Abstract

The invention relates to the technical field of transformers, and provides a rotary transformer, a device with the rotary transformer and electric driving equipment, the rotary transformer comprises a rotor part and a stator part, the rotor part comprises a rotor main body and a rotor winding, and the rotor winding has a tangential direction and a normal direction which are perpendicular to each other; the stator part comprises a stator main body and a stator winding; wherein a first structure air gap is formed between the rotor main body and the stator main body, a second structure air gap is formed in the stator main body, and the second structure air gap is located on at least one side of the normal direction of the rotor winding relative to the rotor winding. According to the rotary transformer provided by the invention, compared with a rotary transformer which only has the first structure air gap, the double structure air gaps can effectively reduce eddy current loss, the problem that winding current is intensively distributed on one side of the rotor winding is solved, the effective utilization area of the rotor winding is increased, the current distribution is more uniform, and the service life of the rotary transformer is prolonged. And the energy transmission efficiency of the rotary transformer is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of transformers, and in particular provides a rotary transformer, a device having the rotary transformer, and an electric drive device. Background Art

[0002] A resolver is a special type of sensor with a motor-like structure, designed to allow one or more windings to rotate. Typically, a resolver consists of a fixed portion and a rotating portion that rotates relative to the fixed portion. Resolvers are used in devices and equipment that require rotation or movement, such as generators, motors, and rotating platforms.

[0003] When the rotating part and the fixed part are assembled in a non-contact manner, there is an inevitable structural air gap at the junction of the two to meet the above-mentioned requirement of relative rotation between the two.

[0004] However, magnetic lines of force similar to a quarter-circular structure will be generated at the structural air gap. The edge magnetic flux of the structural air gap generates a magnetic field intensity that can be a normal magnetic field component and a tangential magnetic field component. Among them, the normal magnetic field component plays a dominant role in eddy current loss and is also one of the reasons for uneven winding current distribution and severe local heating. Summary of the Invention

[0005] The purpose of the embodiments of the present application is to provide a rotary transformer, a device having a rotary transformer, and an electric drive device, aiming to solve the problems of high eddy current loss and uneven winding current distribution caused by the structural air gap in the existing non-contact assembled rotary transformer.

[0006] To achieve the above objectives, the technical solutions adopted in the embodiments of the present application are:

[0007] In a first aspect, an embodiment of the present application provides a rotary transformer, comprising:

[0008] A rotor portion, the rotor portion comprising a rotor body capable of rotating about its own axis and a rotor winding capable of rotating about the axis along with the rotor body, the rotor winding being formed by a planar winding method and having a tangential direction and a normal direction perpendicular to each other;

[0009] a stator portion, the stator portion comprising a stator body enclosed with the rotor body to form an accommodating cavity, and a stator winding disposed in the accommodating cavity;

[0010] The rotor winding is placed in the accommodating cavity, a first structural air gap is formed between the rotor body and the stator body, a second structural air gap is formed on the stator body, and the second structural air gap is located on at least one side of the normal direction of the rotor winding relative to the rotor winding.

[0011] The beneficial effects of the embodiments of the present application: The rotating transformer provided by the present application additionally forms a second structural air gap on the stator body, and the second structural air gap and the first structural air gap are both located in the normal direction of the rotor winding. The normal magnetic field component generated by the edge magnetic flux at the second structural air gap can be offset by the normal magnetic field component generated by the edge magnetic flux at the first structural air gap, thereby achieving the closure of the magnetic lines of force in the accommodating cavity along the tangential direction of the rotor winding. Compared with the rotating transformer with only the first structural air gap, the dual-structure air gap can effectively reduce eddy current loss, improve the problem of winding current concentrated on one side of the rotor winding, increase the effective utilization area of ​​the rotor winding, and make the current distribution more uniform, thereby improving the energy transmission efficiency of the rotating transformer.

[0012] In some embodiments, the stator body includes a first stator sub-section and a second stator sub-section enclosed with the first stator sub-section to form a concave cavity.

[0013] One end of the second stator sub-part forms the first structural air gap with the outer wall of the rotor body, and the other end of the second stator sub-part forms the second structural air gap with the outer wall of the first stator sub-part.

[0014] In some embodiments, a plurality of second structural air gaps are further formed on the second stator sub-part; and / or,

[0015] A plurality of second structural air gaps are also formed on the first stator sub-part.

[0016] In some embodiments, the extension direction of the first structural air gap and the extension direction of the second structural air gap are both the same as the normal direction, and the distance between the first structural air gap and any one of the second structural air gaps is smaller than the width of the accommodating cavity in the tangential direction.

[0017] In some embodiments, a magnetic conductor is provided at at least one of the second structural air gaps, and the magnetic permeability of the magnetic conductor is lower than the magnetic permeability of the stator body.

[0018] In some embodiments, the rotor body includes a first rotor sub-section extending along the normal direction, and the first structural air gap is formed between the first rotor sub-section and the stator body.

[0019] In some embodiments, the rotor body further includes a second rotor sub-section provided on the first rotor sub-section and extending outwardly along the tangential direction, and the first structural air gap is formed between the second rotor sub-section and the stator body.

[0020] In some embodiments, the first rotor subsection has a first end and a second end oppositely disposed along the normal direction, and an end surface of the first end and / or an end surface of the second end is higher than an end surface of the stator body in the normal direction.

[0021] In some embodiments, the rotary transformer includes a rotating shaft, and the first rotor sub-section is extended along the axial direction of the rotating shaft; or, the first rotor sub-section is extended along the radial direction of the rotating shaft.

[0022] In some embodiments, the stator winding is formed by a surrounding winding method, and the rotor winding is located between two adjacent stator windings; or, the stator winding and the rotor winding are stacked.

[0023] In some embodiments, the stator winding is formed by a planar winding method, and the stator winding and the rotor winding are stacked.

[0024] In some embodiments, the rotor body includes a plurality of sub-rotor bodies, and the sub-rotor bodies are arranged around the rotation center line at intervals; and / or,

[0025] The stator body includes a plurality of sub-stator bodies, and the sub-stator bodies are arranged around the rotation center line at intervals.

[0026] In a second aspect, an embodiment of the present application provides a device having a rotary transformer, including the rotary transformer described above.

[0027] Beneficial effects of the embodiments of the present application: The device with a rotary transformer provided by the present application has a higher output efficiency based on the above-mentioned rotary transformer.

[0028] In some embodiments, the device is an electric drive system, which includes a motor and the rotary transformer, wherein the rotor body of the rotary transformer is connected to the rotor of the motor.

[0029] In a third aspect, an embodiment of the present application provides an electric drive device, comprising the rotary transformer described above.

[0030] Beneficial effects of the embodiments of the present application: The electric drive device provided by the present application, based on the above-mentioned rotary transformer, has higher output efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 It is a structural diagram of a rotary transformer in the prior art;

[0033] Figure 2 for Figure 1 Schematic diagram of the resolver in simulation;

[0034] Figure 3 A schematic structural diagram of a vehicle provided in an embodiment of the present invention;

[0035] Figure 4 A schematic cross-sectional view of the rotary transformer provided in the first embodiment of the present invention;

[0036] Figure 5 A schematic cross-sectional view of a rotary transformer provided in a second embodiment of the present invention;

[0037] Figure 6 A schematic cross-sectional view of a rotary transformer according to a third embodiment of the present invention;

[0038] Figure 7 A schematic cross-sectional view of a rotary transformer according to a fourth embodiment of the present invention;

[0039] Figure 8 A schematic cross-sectional view of a rotary transformer according to a fifth embodiment of the present invention;

[0040] Figure 9 A schematic cross-sectional view of a rotary transformer according to a sixth embodiment of the present invention;

[0041] Figure 10 A schematic cross-sectional view of a rotary transformer according to a seventh embodiment of the present invention;

[0042] Figure 11 A schematic cross-sectional view of the rotary transformer provided in the eighth embodiment of the present invention;

[0043] Figure 12 A schematic cross-sectional view of a rotary transformer according to a ninth embodiment of the present invention;

[0044] Figure 13 A schematic cross-sectional view of a rotary transformer provided in a tenth embodiment of the present invention;

[0045] Figure 14A schematic structural diagram of a rotary transformer provided in the eleventh embodiment of the present invention;

[0046] Figure 15 A schematic diagram of a rotary transformer provided in the first embodiment of the present invention under simulation;

[0047] Figure 16 This is a schematic diagram of a rotary transformer provided in the third embodiment of the present invention under simulation;

[0048] Figure 17 This is a schematic diagram of the rotary transformer provided in the fourth embodiment of the present invention under simulation.

[0049] Among them, the reference numerals in the figures are:

[0050] 1. Fixed part; 2. Rotating part; 3. Winding; 4. Structural air gap;

[0051] 10,000 vehicles

[0052] 1000, battery; 2000, controller; 3000, motor; 100, rotary transformer;

[0053] 10. Stator section; 11. Stator body; 12. Stator winding; 111. First stator sub-section; 112. Second stator sub-section; 10a. Sub-stator body;

[0054] 20, rotor part; 21, rotor body; 22, rotor winding; 211, first rotor sub-part; 212, second rotor sub-part; 21a, first end; 21b, second end; 20a, sub-rotor body;

[0055] 30. Accommodating cavity;

[0056] 41. First structural air gap; 42. Second structural air gap; 43. Magnetic conductor;

[0057] 50. Rotating shaft;

[0058] X, tangential direction; Y, normal direction; Z, extension direction. DETAILED DESCRIPTION

[0059] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0060] In the description of the present invention, it should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0061] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0062] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0063] A rotary transformer is a sensor with a structure similar to that of a motor. Figure 1 As shown, the rotary transformer includes a fixed part 1 and a rotating part 2 that rotates coaxially with the fixed part 1. Specifically, when non-contact assembly is adopted, an inevitable structural air gap 4 is formed between the rotating part 2 and the fixed part 1 to meet the requirement of relative rotation between the two.

[0064] However, continue to refer to Figure 1 It can be seen that the magnetic field lines similar to the quarter-circular structure generated at the air gap 4 of the above structure and the magnetic field intensity generated by the edge magnetic flux of the air gap 4 can be divided into the normal magnetic field component H y and the tangential magnetic field component H x , and the tangential magnetic field component H x The smaller the proportion, the greater the normal magnetic field component H y The larger the proportion, the normal magnetic field component H y It plays a dominant role in eddy current loss. Figure 2 , Figure 2Figure 3 is a schematic diagram of the rotating transformer under simulation. It can be seen from the figure that the edge magnetic flux generated by the structural air gap 4 produces large eddy current losses, and the current on the winding 3 of the rotating part 2 is concentrated on the leftmost side of the winding 3 along the X-axis. That is, it can be seen from the figure that the leftmost side of the winding 3 shows a local high red result, which also indicates that the current is concentrated on the leftmost side of the winding 3, resulting in a low effective utilization area of ​​the winding 3 and uneven current distribution.

[0065] In view of this, the present application provides a rotating transformer, which, on the basis of forming a first structural air gap between the stator body and the rotor body, additionally forms a second structural air gap on the stator body, and makes the second structural air gap and the first structural air gap both located in the normal direction of the rotor winding. Then, the normal magnetic field component generated by the edge magnetic flux at the second structural air gap can be offset by the normal magnetic field component generated by the edge magnetic flux at the first structural air gap, thereby achieving the closure of the magnetic lines of force in the accommodating cavity along the tangential direction of the rotor winding, so as to reduce eddy current loss, and increase the effective utilization area of ​​the rotor winding, so that the current distribution on the rotor winding is more uniform.

[0066] An embodiment of the present application provides a device having the above-mentioned rotary transformer 100. The device having the rotary transformer 100 can be a device that rotates or moves when working, such as a generator, a motor, a turbine, a radar, a camera, and an underwater robot.

[0067] Of course, the rotary transformer 100 provided in the present application is not limited to being applicable to the above-mentioned devices, but can also be applicable to all devices using the rotary transformer 100.

[0068] The rotary transformer 100 provided in the present application can also be applied to electric drive equipment, which includes electric drive equipment such as vehicles, portable devices, ships, spacecraft, power tools, etc., wherein the vehicle can be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc.; the spacecraft includes airplanes, rockets, space shuttles and spacecraft, etc.; the power tools include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, electric airplane toys, etc.; the power tools include metal cutting power tools, grinding power tools, assembly power tools and iron power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers, etc.

[0069] Of course, the rotary transformer 100 provided in this application is not limited to being applicable to the electric drive equipment described above, but can also be applicable to all electric drive equipment using the rotary transformer 100. However, for the sake of simplicity, the following embodiments are described using electric vehicles as an example.

[0070] For example, see Figure 3 , Figure 3 This is a schematic diagram of the structure of a vehicle according to an embodiment of the present application. The vehicle can be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle. Vehicle 10000 can be equipped with a battery 1000, a controller 2000, a motor 3000, and a resolver 100. The controller 2000 is used to control the battery 1000 to supply power to the motor 3000, and the resolver 100 is used to electrically connect to the motor 3000.

[0071] Please refer to Figure 4 and Figure 5 The rotary transformer 100 provided in the embodiment of the present application includes a rotor part 20 and a stator part 10 .

[0072] The rotor portion 20 includes a rotor body 21 that rotates around its own axis and a rotor winding 22 that rotates around the axis along with the rotor body 21. The rotor winding 22 is formed by a planar winding method and has a tangential direction X and a normal direction Y that are perpendicular to each other.

[0073] The stator portion 10 includes a stator body 11 enclosed with the rotor body 21 to form a receiving cavity 30 and a stator winding 12 disposed in the receiving cavity 30;

[0074] The rotor winding 22 is placed in the accommodating cavity 30, a first structural air gap 41 is formed between the rotor body 21 and the stator body 11, and a second structural air gap 42 is formed on the stator body 11. The second structural air gap 42 is located on at least one side of the normal direction of the rotor winding 22 relative to the rotor winding 22.

[0075] It can be understood that the stator portion 10 is the portion of the rotary transformer 100 that remains relatively stationary during operation, and the rotor portion 20 is the portion of the rotary transformer 100 that rotates relative to the stator portion 10. Furthermore, the relative arrangement of the stator portion 10 and the rotor portion 20 is adjusted according to actual needs. For example, the stator portion 10 is coaxially arranged with the rotor portion 20 about the central axis of rotation of the rotor portion 20, and the stator portion 10 is sleeved on the outer periphery of the rotor portion 20. The structure of such a rotary transformer 100 is similar to the structural arrangement of an inner rotor motor. Alternatively, the rotor portion 20 is coaxially arranged with the stator portion 10 about the central axis of the stator portion 10, and the rotor portion 20 is sleeved on the outer periphery of the stator portion 10. The structure of such a rotary transformer 100 is similar to the structural arrangement of an outer rotor motor.

[0076] At the same time, the stator portion 10 and the rotor portion 20 are assembled in a non-contact manner, and thus a first structural air gap 41 is formed between the stator portion 10 and the rotor portion 20. The first structural air gap 41 is unavoidable when the stator portion 10 and the rotor portion 20 are assembled in a non-contact manner. That is, the rotor portion 20 can rotate relative to the stator portion 10 only with the presence of the first structural air gap 41.

[0077] The rotor body 21 can be made of materials such as silicon steel sheets, ferrites, microcrystals, ultramicrocrystals or Permalloy, and is used to connect to the rotating shaft. According to actual usage requirements, the rotor body 21 can be arranged along the axial direction of the rotating shaft, or the rotor body 21 can also be arranged along the radial direction of the rotating shaft.

[0078] The rotor winding 22 includes, but is not limited to, solid wire, Litz wire, copper foil, and flexible circuit board windings. The rotor winding 22 is connected to the rotor body 21 to ensure that the rotor winding 22 rotates around the axis with the rotor body 21.

[0079] Planar winding is a layout method of electromagnetic winding, in which the winding coil is arranged along a specific path in a plane, that is, each loop of the winding coil is located on the same plane, and adjacent loops can be arranged in parallel or crosswise. The rotor winding 22 formed by planar winding has the advantages of compact structure, good electromagnetic performance and convenient manufacturing.

[0080] After the rotor winding 22 is planarly wound and formed, it forms a flat plate-like structure. The tangential direction X of the rotor winding 22 is the X-axis direction in the figure, which is parallel to the plane where the flat plate-like structure is located. The normal direction Y of the rotor winding 22 is the Y-axis direction in the figure, which is perpendicular to the plane where the flat plate-like structure is located.

[0081] It should be noted that the normal direction Y of the rotor winding 22 should be the same as the extension direction of the rotor body 21. For example, when the rotor body 21 is extended along the axial direction of the rotating shaft, the normal direction Y of the rotor winding 22 is parallel to the axial direction of the rotating shaft. For another example, when the rotor body 21 is extended along the radial direction of the rotating shaft, the normal direction Y of the rotor winding 22 is perpendicular to the axial direction of the rotating shaft.

[0082] The stator body 11 can be made of silicon steel sheets, ferrite, microcrystals, ultramicrocrystals, or permalloy. The stator body 11 and the rotor body 21 are enclosed to form an accommodating cavity 30 .

[0083] For example, Figure 4 As shown, in the axial cross-sectional direction of the rotary transformer 100 , the rotor body 21 has a similar tubular structure, and the stator body 11 has a similar concave structure. The rotor body 21 and the stator body 11 enclose a receiving cavity 30 .

[0084] For example, Figure 8 As shown, in the axial cross-sectional direction of the rotary transformer 100 , the rotor body 21 has a similar concave structure, and the stator structure 200 also has a similar concave structure. The rotor body 21 and the stator body 11 similarly enclose each other to form an accommodating cavity 30 .

[0085] The stator winding 12 includes, but is not limited to, solid wire, Litz wire, copper foil, and flexible circuit board windings. The stator winding 12 is connected to the stator body 11 and remains relatively stationary with the rotor winding 22.

[0086] The rotor winding 22 and the stator winding 12 are both placed in the accommodating cavity 30. The stator winding 12 can be formed in the accommodating space by a surrounding winding method, that is, each coil of the stator winding 12 is coaxially wound with the rotation center axis of the rotor body 21 as the center. Of course, the stator winding 12 can also be formed by a planar winding method.

[0087] The second structural air gap 42 should be a through hole or through slot structure penetrating the stator body 11 , that is, the originally integral stator body 11 is divided into at least two parts, that is, the stator body 11 is divided into multiple parts due to the formation of the second structural air gap 42 .

[0088] For example, in the axial cross-sectional direction of the rotary transformer 100, the number of the second structural air gap 42 is one, and the stator body 11 divided by the second structural air gap 42 should include a first portion arranged along the tangential direction X and an L-shaped second portion; alternatively, the number of the second structural air gaps 42 is two, and the stator body 11 divided by the second structural air gap 42 should include two first portions arranged along the tangential direction X and spaced apart, and a second portion located between the two first portions; alternatively, the number of the second structural air gaps 42 is multiple, and the stator body 11 divided by the second structural air gap 42 should include two first portions arranged along the tangential direction X and spaced apart, each first portion being divided into multiple segments by the remaining second structural air gaps 42, and a second portion located between the two first portions, which is also divided into at least two segments by the remaining second structural air gaps 42.

[0089] Opposite to the normal direction Y of the rotor winding 22 is the tangential direction X of the rotor winding 22. The tangential direction X of the rotor winding 22 is a direction parallel to the plane after plane winding. Since the normal magnetic field component of the magnetic field intensity generated by the edge magnetic flux at the structural air gap plays a dominant role in the eddy current loss, the second structural air gap 42 should be located in the normal direction Y of the rotor winding 22. That is, in addition to the extension direction of the structural air gap being coplanar with the plane where the rotor winding 22 is located, the extension direction of the structural air gap is The direction is the direction in which it passes through the stator body 10. The extension direction of the structural air gap can be parallel to or at an angle to the normal direction Y, or parallel to or at an angle to the tangential direction Z. The remaining structural air gaps that are not coplanar with the plane where the rotor winding 22 is located are referred to as structural air gaps located in the normal direction Y of the rotor winding 22, that is, the structural air gap located in the normal direction Y of the rotor winding 22 has a normal magnetic field component, while the normal magnetic field component of the structural air gap located in the tangential direction X of the rotor winding 22 is almost zero.

[0090] In an axial cross-section of the rotary transformer 100 , the stator body 11 has at least three oriented sides relative to the rotor winding 22 in the normal direction Y of the rotor winding 22 . That is, the stator body 11 surrounds and wraps around the rotor winding 22 in a semi-open manner. Therefore, the second structural air gap 42 can be formed on any one or more of the at least three oriented sides of the stator body 11 .

[0091] For example, Figure 4 As shown, in the axial cross-sectional direction of the rotary transformer 100, the number of the first structural air gaps 41 is two, and the number of the second structural air gaps 42 is also two, the opening and extending directions of the two first structural air gaps 41 are the same as the normal direction Y of the rotor winding 22, and the opening and extending directions of the two second structural air gaps 42 are also the same as the normal direction Y of the rotor winding 22.

[0092] For example, Figure 5 As shown, in the axial cross-sectional direction of the rotary transformer 100, the number of the first structural air gaps 41 is two, and the number of the second structural air gaps 42 is also two. The opening and extending directions of the two first structural air gaps 41 are the same as the normal direction Y of the rotor winding 22, and the opening and extending directions of the two second structural air gaps 42 are the same as the tangential direction X of the rotor winding 22. However, the two second structural air gaps 42 are not coplanar with the plane where the rotor winding 22 is located. In this case, the second structural air gaps 42 are also referred to as structural air gaps located in the normal direction Y of the rotor winding 22.

[0093] Please refer to Figure 15 , Figure 15This is a schematic diagram of the rotary transformer 100 provided in Example 1 of the present application under simulation. It can be seen from the figure that the edge magnetic flux of the second structure air gap 42 and the edge of the first structure air gap 41 cancel each other out, and the current distribution on the rotor winding 22 is more dispersed. Therefore, the rotor winding 22 as a whole is high red, which also indicates that the effective utilization area of ​​the rotor winding 22 is higher and the current distribution is more uniform.

[0094] The rotary transformer 100 provided in the present application additionally forms a second structural air gap 42 on the stator body 11, and the second structural air gap 42 and the first structural air gap 41 are both located in the normal direction Y of the rotor winding 22. The normal magnetic field component generated by the edge magnetic flux at the second structural air gap 42 can be offset by the normal magnetic field component generated by the edge magnetic flux at the first structural air gap 41, thereby achieving the closure of the magnetic lines of force in the accommodating cavity 30 along the tangential direction X of the rotor winding 22. Compared with the rotary transformer 100 with only the first structural air gap 41, the dual-structure air gap can effectively reduce eddy current loss, improve the problem of the winding current being concentrated on one side of the rotor winding 22, increase the effective utilization area of ​​the rotor winding 22, and make the current distribution more uniform, thereby improving the energy transmission efficiency of the rotary transformer 100.

[0095] Please refer to Figure 4 、 Figure 5 and Figure 7 In some embodiments, the stator body 11 includes a first stator sub-section 111 and a second stator sub-section 112 enclosed with the first stator sub-section 111 to form a concave cavity.

[0096] One end of the second stator sub-part 112 forms a first structural air gap 41 with the outer wall of the rotor body 21 , and the other end of the second stator sub-part 112 forms a second structural air gap 42 with the outer wall of the first stator sub-part 111 .

[0097] It is understood that, in order to form an enclosed structure with the rotor body 21 to form the accommodating cavity 30, the first stator sub-section 111 and the second stator sub-section 112 form a U-shaped structure or a quasi-U-shaped structure. For example, there are two second stator sub-sections 112, which are arranged along the tangential direction X, and the first stator sub-section 111 is arranged along the normal direction Y. Alternatively, there is one second stator sub-section 112, which is arranged along the tangential direction X, and the first stator structure 200 is L-shaped or quasi-L-shaped, that is, the first stator structure 200 includes a first portion arranged along the tangential direction X and a second portion connected to the first portion and arranged along the normal direction Y.

[0098] The end of the second stator sub-part 112 away from the first stator sub-part 111 should be assembled with the rotor body 21 in a non-contact manner to form a first structural air gap 41 .

[0099] There are two situations in which the second structural air gap 42 is formed between the end of the second stator sub-part 112 facing the first stator sub-part 111 and the outer wall of the first stator sub-part 111:

[0100] Case 1, such as Figure 4 As shown, the extending direction of the second structural air gap 42 is parallel to the normal direction Y; Case 2, as shown Figure 5 As shown, the extending direction of the second structural air gap 42 is parallel to the tangential direction.

[0101] Alternatively, as Figure 4 As shown, the number of the first structure air gaps 41 is two, the number of the second structure air gaps 42 is also two, and the extension directions of the two second structure air gaps 42 are parallel to the normal direction Y. In this way, the normal magnetic field components generated by the edge magnetic fluxes of the two first structure air gaps 41 are opposite to the directions of the normal magnetic field components generated by the edge magnetic fluxes of the two second structure air gaps 42, and can offset each other.

[0102] In summary, according to actual usage requirements, the number of second stator sub-sections 112 in the stator body 11, that is, the number and setting position of the second structural air gap 42, is adjusted, and the normal magnetic field component generated by the edge magnetic flux of the first structural air gap 41 is reduced or offset, thereby making the current distribution on the surface of the rotor winding 22 more uniform, reducing the eddy current loss on the surface of the rotor winding 22, and reducing the probability of severe local heating of the rotor winding 22.

[0103] Please refer to Figure 7 In some embodiments, a plurality of second structural air gaps 42 are further formed on at least one second stator sub-section 112 ; and / or a plurality of second structural air gaps 42 are further formed on the first stator sub-section 111 .

[0104] It is understandable that the second structural air gap 42 may also be distributed on the first stator sub-section 111 ; or distributed on the second stator sub-section 112 ; or distributed on both the first stator sub-section 111 and the second stator sub-section 112 .

[0105] When the second structural air gap 42 is distributed on the first stator sub-section 111, that is, the second structural air gap 42 divides the integral first stator sub-section 111 into multiple parts; or when the second structural air gap 42 is distributed on the second stator sub-section 112, the second structural air gap 42 divides the integral second stator sub-section 112 into multiple parts.

[0106] For example, Figure 17 As shown, Figure 17This is a schematic diagram of the rotary transformer 100 provided in the fourth embodiment of the present application under simulation; in addition to being provided between the end of the second stator sub-section 112 and the outer wall of the first stator sub-section 111, the second structural air gap 42 in the figure is also formed on the second stator sub-section 112. As can be seen from the figure, the magnetic lines of force inside the accommodating cavity 30 are closed along the tangent direction of the rotor winding 22, and the magnetic lines of force are approximately parallel to the tangential direction X of the rotor winding 22. Therefore, the current distribution on the surface of the rotor winding 22 is uniform. As can be seen from the figure, the rotor winding 22 has a high red phenomenon at both opposite ends of the tangential direction X, which also shows that the current distribution on the surface of the rotor winding 22 is more dispersed and the effective utilization area is larger.

[0107] In this way, increasing the number of the second structure air gaps 42 according to actual use requirements can effectively improve the uneven current distribution on the surface of the rotor winding 22 and increase its effective utilization area.

[0108] Please refer to Figure 4 In some embodiments, the extension direction of the first structural air gap 41 and the extension direction of the second structural air gap 42 are both the same as the normal direction Y, and the distance d1 between the first structural air gap 41 and any second structural air gap 42 is less than the width w of the accommodating cavity 30 in the tangential direction X.

[0109] It can be understood that the above-mentioned second structural air gap 42 should be distributed on the second stator sub-section 112, or on the portion of the L-shaped first stator sub-section 111 in the tangential direction X. In this way, the extension direction of the second structural air gap 42 is the same as the normal direction Y.

[0110] The distance d1 between the first structural air gap 41 and any second structural air gap 42 can be the length of the current second stator sub-section 112 in the tangential direction X, or the length of the L-shaped first stator sub-section 111 after it is further divided in the tangential direction X. Alternatively, when there are multiple second structural air gaps 42, the distance d1 between the first structural air gap 41 and any second structural air gap 42 can also be the length of the divided portion of the current second stator sub-section 112 in the tangential direction X.

[0111] The width w of the accommodating cavity 30 in the tangential direction X is also the width of the current magnetic core window, that is, the width of the cross-sectional space formed by the accommodating cavity 30 in the tangential direction X.

[0112] For example, Figure 4As shown, the stator body 11 includes a first stator sub-section 111 and two second stator sub-sections 112. Therefore, the distance d1 between the first structural air gap 41 and the second structural air gap 42 is equal to the length of the second stator sub-section 112 in the tangential direction X. Furthermore, the width w of the accommodating cavity 30 in the tangential direction X is equal to the width of the current magnetic core window. Because the second stator sub-sections 112 are not divided by the second structural air gaps 42, the ratio of d1 to w can be infinitely close to 1, as long as the gaps of the first structural air gap 41 and the second structural air gap 42 are sufficiently small.

[0113] For example, Figure 7 As shown, the stator body 11 includes a first stator sub-section 111 and two second stator sub-sections 112. The ends of the two second stator sub-sections 112 facing the first stator sub-section 111 form a second structural air gap 42 with the outer wall of the first stator sub-section 111. A second structural air gap 42 is also formed in the second stator sub-section 112, dividing the second stator sub-section 112 into two equal parts. Therefore, the spacing d1 between the first structural air gap 41 and the second structural air gap 42 is equal to the length of each part of the second stator sub-section 112 in the tangential direction X. Furthermore, the width w of the accommodating cavity 30 in the tangential direction X is equal to the width of the magnetic core window. In this case, the ratio of d to w is 0.5, or close to 0.5.

[0114] In summary, the ratio of d1 to w may range from 0.1 to 1. For example, the ratio of d1 to w may be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, etc.

[0115] Please refer to Figure 4 、 Figure 6 and Figure 7 In some embodiments, in the normal direction Y, the distance d2 from the opposite ends of the rotor winding 22 to the inner wall of the accommodating cavity 30 and the width w of the accommodating cavity 30 in the tangential direction X also have a certain proportional relationship. For example, the ratio of d2 to w can range from 0.1 to 3. For example, the ratio of d2 to w can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, etc.

[0116] Optionally, the distances d2 from the middle area of ​​the accommodating cavity 30 at the rotor winding 22 , that is, from the opposite ends of the rotor winding 22 to the inner wall of the accommodating cavity 30 are equal.

[0117] Please refer to Figure 6 In some embodiments, a magnetic conductor 43 is provided at at least one second structural air gap 42 , and the magnetic permeability of the magnetic conductor 43 is lower than the magnetic permeability of the stator body 11 .

[0118] It can be understood that after the second structural air gap 42 is formed on the stator body 11, theoretically, the magnetic permeability of the first stator sub-section 111 and the magnetic permeability of the second stator sub-section 112 are the same. Therefore, the magnetic permeability of the magnetic conductor 43 only needs to be smaller than that of one of the stator sub-sections. Of course, the stator body 11 can also be composed of stator sub-sections with different magnetic permeabilities. In this case, the magnetic permeability of the magnetic conductor 43 is smaller than that of one of the stator sub-sections, or smaller than that of both stator sub-sections.

[0119] Here, the magnetic conductor 43 may be made of a material with low magnetic permeability, and the material of the magnetic conductor 43 includes but is not limited to copper, aluminum, carbon steel, stainless steel, and the like.

[0120] Furthermore, the magnetic conductor 43 may be disposed in the second structural air gap 42 in a manner that completely fills the second structural air gap 42, i.e., within an allowable error range, there is no gap between the outer wall of the magnetic conductor 43 and the inner wall of the second structural air gap 42. Alternatively, the magnetic conductor 43 may be disposed in the second structural air gap 42 in a manner that partially fills the second structural air gap 42, i.e., after the magnetic conductor 43 is completely disposed, a gap still exists between the outer wall of the magnetic conductor 43 and the inner wall of the second structural air gap 42.

[0121] The gap of the first structural air gap 41 is a, and the gap of the second structural air gap 42 is b. The units of the two structural air gaps are both mm. The ratio of a to b ranges from 0.5 to 2, that is, the ratio of a to b can be 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, etc. Then, after the magnetic conductor 43 is provided in the second structural air gap 42, the following relationship exists: b = μ r a, where μ r is the magnetic permeability of the magnetic conductor 43.

[0122] For example, Figure 16 As shown, Figure 16 This is a schematic diagram of the rotary transformer 100 provided in Example 3 of the present application under simulation. It can be seen from the figure that after the magnetic conductor 43 is added at the two second structure air gaps 42, the edge magnetic flux of the second structure air gap 42 and the edge of the first structure air gap 41 are offset, and the current distribution on the rotor winding 22 is more dispersed. Therefore, the rotor winding 22 as a whole is high red, which also indicates that the effective utilization area of ​​the rotor winding 22 is higher and the current distribution is more uniform.

[0123] Thus, arranging the magnetic conductor 43 in the second structural air gap 42 can enrich the implementation methods of reducing the loss of the rotor winding 22 . At the same time, the magnetic conductor 43 can also be used to limit the relative movement of the stator sub-parts of the stator body 11 , which helps to fix the stator part 10 .

[0124] Please refer to Figures 4 to 8In some embodiments, the rotor body 21 includes a first rotor sub-portion 211 extending along the normal direction Y, and a first structural air gap 41 is formed between the first rotor sub-portion 211 and the stator body 10 .

[0125] It can be understood that the first rotor sub-section 211 is the main part of the rotor body 21 and is also the part connected to the external rotating shaft or input shaft. The first rotor sub-section 211 is arranged in an I-shape or a 1-shape in the normal direction Y, and the stator body 11 and the outer wall or inner wall of the first rotor sub-section 211 form a first structural air gap 41.

[0126] Alternatively, as Figure 4 As shown, the stator body 11 includes a first stator sub-section 111 and two second stator sub-sections 112. The same end of the two second stator sub-sections 112 forms a first structural air gap 41 with the outer wall of the first rotor sub-section 211, and the other end of the two second stator sub-sections 112 forms a second structural air gap 42 with the outer wall of the first stator sub-section 111. In addition, the extension direction of the first structural air gap 41 and the extension direction of the second structural air gap 42 are both the same as the normal direction Y. In addition, the stator winding 12 and the rotor winding 22 are symmetrically arranged about the midpoint of the first stator sub-section 111. In this way, the structure of the rotary transformer 100 is mirrored. Then, the normal magnetic field component generated by the fringe magnetic flux at the second structural air gap 42 completely offsets the normal magnetic field component generated by the fringe magnetic flux at the first structural air gap 41, further reducing the eddy current loss of the rotor winding 22.

[0127] In this way, the I-shaped or 1-shaped first rotor sub-section 211 can minimize the additional weight of the rotor body 21 , and the rotor body 21 can be closer to the central axis of rotation, which can effectively reduce centrifugal force and is suitable for high-speed rotation.

[0128] Please refer to Figure 8 and Figure 9 In some embodiments, the rotor body 21 further includes a second rotor sub-section 212 disposed on the first rotor sub-section 211 and extending outward along the tangential direction X, and a first structural air gap 41 is formed between the second rotor sub-section 212 and the stator body 10 .

[0129] It can be understood that the second rotor sub-section 212 is the portion of the rotor body 21 that can adapt to the stator structure 200 . After the second rotor sub-section 212 is added to the first rotor sub-section 211 , the overall structure of the rotor body 21 changes accordingly.

[0130] For example, Figure 8 As shown, two second rotor sub-parts 212 are provided on the outer wall of the first rotor sub-part 211 , so that the cross section of the rotor body 21 in the tangential direction X is U-shaped or quasi-U-shaped.

[0131] For example, Figure 9 As shown, a second rotor sub-part 212 is provided on the outer wall of the first rotor sub-part 211 , so that the cross section of the rotor body 21 in the tangential direction X is L-shaped or quasi-L-shaped.

[0132] Please refer to Figure 10 In some embodiments, the first rotor sub-section 211 has a first end 21a and a second end 21b that are oppositely arranged along the normal direction Y, and the end surface of the first end 21a and / or the end surface of the second end 21b are higher than the end surface of the stator body 11 in the normal direction Y.

[0133] It can be understood that the end face of the first end 21a of the first rotor sub-part 211 in the normal direction Y is higher than the end face of the stator body 11 in the normal direction Y; or, the end face of the second end 21b of the first rotor sub-part 211 in the normal direction Y is higher than the end face of the stator body 11 in the normal direction Y; or, the end face of the first end 21a and the end face of the second end 21b of the first rotor sub-part 211 in the normal direction Y are both higher than the end face of the stator body 11 in the normal direction Y.

[0134] In this way, the rotor body 21 is extended in the normal direction Y, which can further reduce the eddy current in the external rotating shaft or the input shaft caused by the magnetic flux leakage from the structural air gap.

[0135] Please refer to Figures 4 to 13 In some embodiments, the rotary transformer 100 includes a rotating shaft 50 , and the first rotor sub-section 211 extends along the axial direction of the rotating shaft 50 ; or, the first rotor sub-section 211 extends along the radial direction of the rotating shaft 50 .

[0136] It can be understood that the rotating shaft 50 is a shaft-like structure used to drive the first rotor sub-section 211 to rotate around the axis. Therefore, the first rotor sub-section 211 can be arranged on the rotating shaft 50 in the following two situations:

[0137] For example, Figure 10 As shown, the first rotor sub-part 211 is extended along the axial direction of the rotating shaft 50 . Here, the axial direction of the rotating shaft 50 is parallel to the normal direction Y.

[0138] For example, Figure 13 As shown, the first rotor sub-part 211 is extended along the radial direction of the rotating shaft 50 . Here, the radial direction of the rotating shaft 50 is parallel to the normal direction Y.

[0139] In this way, the assembly method of the first rotor sub-part 211 and the rotating shaft 50 can be adjusted according to actual use requirements to improve the structural adaptability of the rotary transformer 100.

[0140] Please refer to Figure 10 and Figure 11In some embodiments, the stator winding 12 is formed by a surrounding winding method, and the rotor winding 22 is located between two adjacent stator windings 12; or, the stator winding 12 and the rotor winding 22 are stacked.

[0141] It can be understood that the surrounding winding method is to wind layer by layer from the inside to the outside with the rotation center line of the rotor part 20 as the winding center. Therefore, in the normal direction Y, the stator winding 12 can be composed of multiple layers of coils.

[0142] The rotor winding 22 and the stator winding 12 can be arranged in the accommodating cavity 30 by placing the rotor winding 22 between two adjacent stator windings 12, so that the rotor winding 22 and the two stator windings 12 form a "sandwich" structure; or, the stator winding 12 is located on one side of the accommodating cavity 30, and the rotor winding 22 is located on the other side of the accommodating cavity 30, and the two are arranged in a stacked manner.

[0143] Please refer to Figure 12 In some embodiments, the stator winding 12 is formed by a planar winding method, and the stator winding 12 and the rotor winding 22 are stacked.

[0144] It can be understood that the stator winding 12 can also be formed by a planar winding method, that is, its forming method is the same as the forming method of the rotor winding 22. After the winding is completed, the stator winding 12 is located on one side of the accommodating cavity 30, and the rotor winding 22 is located on the other side of the accommodating cavity 30, and the two are stacked.

[0145] Please refer to Figure 14 In some embodiments, the rotor body 21 includes a plurality of sub-rotor bodies 20 a , each sub-rotor body 20 a being arranged around the rotation centerline at intervals; and / or

[0146] The stator body 11 includes a plurality of sub-stator bodies 10 a , and the sub-stator bodies 10 a are arranged around the rotation center line at intervals.

[0147] It can be understood that there are gaps between the sub-rotor bodies 20a, rather than forming an annular whole. Similarly, there are gaps between the sub-stator bodies 10a, which are also non-annular wholes.

[0148] Of course, the structures of the two can be adjusted, that is, the rotor body 21 includes a plurality of sub-rotor bodies 20a, and the sub-rotor bodies 20a are arranged around the rotation center line at intervals, but the stator body 11 is a closed annular structure to form a whole; or, the stator body 11 includes a plurality of sub-stator bodies 10a, and each sub-stator body 10a is arranged around the rotation center line at intervals, but the rotor body 21 is a closed annular structure to form a whole; or, the rotor body 21 includes a plurality of sub-rotor bodies 20a and the stator body 11 includes a plurality of sub-stator bodies 10a, each sub-rotor body 20a is arranged around the rotation center line at intervals, and each sub-stator body 10a is arranged around the rotation center line at intervals, and corresponds one to one with the sub-rotor body 20a.

[0149] In this way, the magnetic content of the stator body 11 and the rotor body 21 can be reduced accordingly, and the overall weight of the rotary transformer 100 can be further reduced.

[0150] Please refer to Figure 4 In a specific embodiment, the rotary transformer 100 provided in the embodiment of the present application includes a rotor part 20 and a stator part 10 .

[0151] The rotor portion 20 includes a rotor body 21 that rotates around its own axis and a rotor winding 22 that rotates around the axis along with the rotor body 21. The rotor winding 22 is formed by a planar winding method and has a tangential direction X and a normal direction Y that are perpendicular to each other.

[0152] The stator portion 10 includes a stator body 11 enclosed with the rotor body 21 to form a receiving cavity 30 and a stator winding 12 disposed in the receiving cavity 30;

[0153] In which, the rotor winding 22 is placed in the accommodating cavity 30, a first structural air gap 41 is formed between the rotor body 21 and the stator body 11, and a second structural air gap 42 is formed on the stator body 11. The first structural air gap 41 and the second structural air gap 42 are located in the normal direction Y of the rotor winding 22.

[0154] The stator body 11 includes a first stator sub-section 111 and two second stator sub-sections 112 that are enclosed with the first stator sub-section 111 to form a concave cavity, wherein one end of the second stator sub-section 112 forms a first structural air gap 41 with the outer wall of the rotor body 21, and the other end of the second stator sub-section 112 forms a second structural air gap 42 with the outer wall of the first stator sub-section 111.

[0155] The following characterization is carried out through simulation testing.

[0156] Example 1

[0157] The rotor body 21 of the resolver 100 is I-shaped. The stator body 11 includes a first stator sub-section 111 and two second stator sub-sections 112. A second structural air gap 42 is formed between the ends of the two second stator sub-sections 112 and the outer wall of the first stator sub-section 111. The extension direction of the first structural air gap 41 and the extension direction of the second structural air gap 42 are both the same as the normal direction Y. The gap a of the first structural air gap 41 is equal to the gap b of the second structural air gap 42, and d1 = w and d2 = 0.26w.

[0158] Example 2

[0159] The rotor body 21 of the rotary transformer 100 is I-shaped, and the stator body 11 includes a first stator sub-section 111 and two second stator sub-sections 112. A second structural air gap 42 is formed between the ends of the two second stator sub-sections 112 and the outer wall of the first stator sub-section 111. The extension direction of the first structural air gap 41 and the extension direction of the second structural air gap 42 are both the same as the normal direction Y. Magnetic conductors 43 are also provided at the two second structural air gaps 42. At the same time, the magnetic permeability μ of the magnetic conductor 43 is r The first structure air gap 41 has a gap a and the second structure air gap 42 has a gap b, and b=5a, d1=0.85w, and d2=0.26w.

[0160] Example 3

[0161] The rotor body 21 of the resolver 100 is I-shaped. The stator body 11 includes a first stator sub-section 111 and two second stator sub-sections 112. A second structural air gap 42 is formed between the ends of the two second stator sub-sections 112 and the outer wall of the first stator sub-section 111. Additional second structural air gaps 42 are formed in the two second stator sub-sections 112. The extension direction of the first structural air gap 41 and the extension direction of each second structural air gap 42 are both aligned with the normal direction Y. The gap a of the first structural air gap 41 and the gap b of the second structural air gap 42 are d1 = 0.5w and d2 = 0.26w, respectively.

[0162] Comparative Example 1

[0163] The rotor part of the rotary transformer is I-shaped, and the stator part is U-shaped. The stator part and the rotor part are assembled in a non-contact manner to form a structural air gap. The gap of the structural air gap is the same as the gap of the first structural air gap 41 in each embodiment. In addition, the size specifications, number of windings and winding layout position of the rotary transformer in comparative example 1 are uniform and the same as the rotary transformer 100 in each embodiment. The only variable is that the stator part in comparative example 1 does not form the second structural air gap 42.

[0164] According to the structural models provided in the above embodiments and Comparative Example 1, under the same experimental conditions, relevant parameters and corresponding magnetic field line simulation results as shown in Table 1 can be obtained.

[0165]

[0166] Among them, L p is the primary self-inductance of the rotary transformer 100, M is the secondary mutual inductance of the rotary transformer 100, and L s is the secondary self-inductance of the rotary transformer 100, R p is the parasitic resistance of the primary side of the rotary transformer 100, R s is the parasitic resistance of the secondary side of the rotary transformer 100 .

[0167] It can be seen from the table that the parasitic resistance of the rotary transformer 100 in each embodiment is smaller to varying degrees, which means that the magnetic field component of the rotor winding 22 in the normal direction Y is also reduced accordingly, and at the same time, the eddy current loss is also reduced accordingly.

[0168] Furthermore, the current density in each embodiment is lower than that in comparative example 1, indicating that the current distribution on the plane of the rotor winding 22 in each embodiment is more uniform and the effectively utilized area is larger.

[0169] Specifically, from Figure 2 、 Figures 15 to 17 It can be seen from the figure that the magnetic lines of force in the core window of each embodiment are closed along the tangential direction of the rotor axis, and the magnetic lines of force tend to be parallel to the tangential plane of the rotor winding 22.

[0170] In a second aspect, an embodiment of the present application provides a device having a rotary transformer, including the rotary transformer 100 described above.

[0171] The device with a rotary transformer provided in the present application has a higher output efficiency based on the rotary transformer 100 described above.

[0172] Specifically, the device is an electric drive system, which includes a motor and a rotary transformer, wherein the rotor body of the rotary transformer is connected to the rotor of the motor.

[0173] In a third aspect, an embodiment of the present application provides an electric drive device, including the above-mentioned rotary transformer 100.

[0174] The electric drive device provided in the present application, based on the above-mentioned rotary transformer 100, has a higher output efficiency.

[0175] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A rotary transformer, characterized in that: include: A rotor portion, the rotor portion comprising a rotor body capable of rotating about its own axis and a rotor winding capable of rotating about the axis along with the rotor body, the rotor winding being formed by a planar winding method and having a tangential direction and a normal direction perpendicular to each other; a stator portion, the stator portion comprising a stator body enclosed with the rotor body to form an accommodating cavity, and a stator winding disposed in the accommodating cavity; The rotor winding is placed in the accommodating cavity, a first structural air gap is formed between the rotor body and the stator body, a second structural air gap is formed on the stator body, and the second structural air gap is located on at least one side of the normal direction of the rotor winding relative to the rotor winding.

2. The rotary transformer according to claim 1, wherein: The stator body includes a first stator sub-section and a second stator sub-section enclosed with the first stator sub-section to form a concave cavity. One end of the second stator sub-part forms the first structural air gap with the outer wall of the rotor body, and the other end of the second stator sub-part forms the second structural air gap with the outer wall of the first stator sub-part.

3. The rotary transformer according to claim 2, wherein: A plurality of second structural air gaps are further formed on the second stator sub-part; and / or, A plurality of second structural air gaps are also formed on the first stator sub-part.

4. The rotary transformer according to claim 2 or 3, characterized in that: An extension direction of the first structural air gap and an extension direction of the second structural air gap are both the same as the normal direction, and a distance between the first structural air gap and any one of the second structural air gaps is smaller than a width of the accommodating cavity in the tangential direction.

5. The rotary transformer according to any one of claims 1 to 4, characterized in that: A magnetic conductor is provided at at least one air gap of the second structure, and the magnetic permeability of the magnetic conductor is lower than the magnetic permeability of the stator body.

6. The rotary transformer according to any one of claims 1 to 5, characterized in that: The rotor body includes a first rotor sub-section extending along the normal direction, and the first structural air gap is formed between the first rotor sub-section and the stator body.

7. The rotary transformer according to claim 6, wherein: The rotor body further includes a second rotor sub-section provided on the first rotor sub-section and extending outwardly along the tangential direction, wherein the first structural air gap is formed between the second rotor sub-section and the stator body.

8. The rotary transformer according to claim 6, wherein: The first rotor sub-part has a first end and a second end oppositely arranged along the normal direction, and an end surface of the first end and / or an end surface of the second end is higher than an end surface of the stator body in the normal direction.

9. The rotary transformer according to claim 6, wherein: The rotary transformer includes a rotating shaft, and the first rotor sub-part is extended along the axial direction of the rotating shaft; or the first rotor sub-part is extended along the radial direction of the rotating shaft.

10. The rotary transformer according to any one of claims 1 to 9, characterized in that: The stator winding is formed by a surrounding winding method, and the rotor winding is located between two adjacent stator windings; or, the stator winding and the rotor winding are stacked.

11. The rotary transformer according to any one of claims 1 to 9, characterized in that: The stator winding is formed by a planar winding method, and the stator winding and the rotor winding are stacked.

12. The rotary transformer according to any one of claims 1 to 11, characterized in that: The rotor body includes a plurality of sub-rotor bodies, each of which is arranged around the rotation center line at intervals; and / or, The stator body includes a plurality of sub-stator bodies, and the sub-stator bodies are arranged around the rotation center line at intervals.

13. A device having a rotary transformer, characterized in that: The rotary transformer is the rotary transformer according to any one of claims 1 to 12.

14. The device having a rotary transformer according to claim 13, characterized in that: The device is an electric drive system, which includes a motor and the rotary transformer. The rotor body of the rotary transformer is connected to the rotor of the motor.

15. An electric drive device, characterized in that: The rotary transformer comprises the rotary transformer according to any one of claims 1 to 12.

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