Resolver, apparatus comprising resolver, and electric drive device

Abstract

Provided are a resolver (100), an apparatus comprising the resolver (100), and an electric drive device. The resolver (100) comprises a rotor portion (20) and a stator portion (10); the rotor portion (20) comprises a rotor body (21) and a rotor winding (22), and the rotor winding (22) has a tangential direction (X) and a normal direction (Y) perpendicular to each other; the stator portion (10) comprises a stator body (11) and a stator winding (12); a first structural air gap (41) is formed between the rotor body (21) and the stator body (11), a second structural air gap (42) is formed on the stator body (11), and the second structural air gap (42) is located on at least one side of the normal direction (Y) of the rotor winding (22) with respect to the rotor winding (22).

Description

Rotary transformer, device with rotary transformer and electric drive device

[0001] Cross-reference to related applications

[0002] This application is based on the Chinese Patent Application No. 2024104389205 entitled "Rotary transformer, device with rotary transformer and electric drive device" filed on April 11, 2024, which is incorporated by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the technical field of transformers, and particularly provides a rotary transformer, a device with the rotary transformer and an electric drive device. BACKGROUND

[0004] A rotary transformer is a special type of sensor, which has a structure similar to that of a motor. Its design allows one or more windings to rotate. Generally, the rotary transformer includes a fixed part and a rotating part that rotates around the axis relative to the fixed part. At the same time, the rotary transformer is applied to devices and apparatuses that need to rotate or move, such as generators, motors and rotating platforms.

[0005] When the rotating part and the fixed part are assembled non-contact, there is an inevitable structural air gap at the joint of the two parts to meet the requirement of relative rotation of the two parts.

[0006] However, magnetic lines similar to a quarter-circle structure are generated at the structural air gap. The edge magnetic flux of the structural air gap generates a magnetic field strength that includes a normal magnetic field component and a tangential magnetic field component. The normal magnetic field component plays a dominant role in eddy current loss and is one of the reasons for uneven distribution of winding current and serious local heating. SUMMARY

[0007] The purpose of the embodiments of the present application is to provide a rotary transformer, a device with the rotary transformer and an electric drive device, which aims to solve the problem of high eddy current loss and uneven distribution of winding current caused by the structural air gap in the existing non-contact assembled rotary transformer.

[0008] To achieve the above-mentioned purpose, the technical solutions adopted by the embodiments of the present application are as follows:

[0009] In a first aspect, the embodiments of the present application provide a rotary transformer, which includes:

[0010] A rotor part, which includes a rotor body capable of rotating around its own axis and a rotor winding capable of rotating around the axis with the rotor body, the rotor winding is formed in a planar winding manner and has a tangential direction and a normal direction perpendicular to each other;

[0011] The stator part comprises a stator body which forms a receiving cavity in cooperation with the rotor body, and a stator winding arranged in the receiving cavity;

[0012] The rotor winding is arranged in the receiving cavity, the first structural air gap is formed between the rotor body and the stator body, and the second structural air gap is formed on the stator body and located on at least one side of the rotor winding in the normal direction of the rotor winding.

[0013] The rotary transformer provided by the application has the following advantages: the second structural air gap is additionally formed 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, so that the normal magnetic field component generated by the edge magnetic flux at the second structural air gap can offset the normal magnetic field component generated by the edge magnetic flux at the first structural air gap, thereby realizing the closing of the magnetic lines of force in the receiving cavity along the tangential direction of the rotor winding. Compared with the rotary transformer having only the first structural air gap, the double-structural air gap can effectively reduce the eddy current loss, improve the problem that the winding current is 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 rotary transformer.

[0014] In some embodiments, the stator body comprises a first stator subpart and a second stator subpart which forms a recess in cooperation with the first stator subpart, wherein one end of the second stator subpart forms the first structural air gap with the outer wall of the rotor body, and the other end of the second stator subpart forms the second structural air gap with the outer wall of the first stator subpart.

[0015] In some embodiments, the second stator subpart further forms a plurality of second structural air gaps thereon; and / or,

[0016] The first stator subpart further forms a plurality of second structural air gaps thereon.

[0017] 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 less than the width of the receiving cavity in the tangential direction.

[0018] In some embodiments, at least one of the second structural air gaps is provided with a magnetic conductor, and the magnetic permeability of the magnetic conductor is lower than that of the stator body.

[0019] In some embodiments, the rotor body comprises a first rotor subpart which is arranged in the normal direction, and the first structural air gap is formed between the first rotor subpart and the stator body.

[0020] In some embodiments, the rotor body further comprises a second rotor sub-portion disposed on the first rotor sub-portion and extending outwardly along the tangential direction, and the first structural air gap is formed between the second rotor sub-portion and the stator body.

[0021] In some embodiments, the first rotor sub-portion 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 along the normal direction.

[0022] In some embodiments, the rotary transformer comprises a rotation axis, and the first rotor sub-portion extends along an axial direction of the rotation axis; or the first rotor sub-portion extends along a radial direction of the rotation axis.

[0023] In some embodiments, the stator windings are formed in a ring winding manner, and the rotor winding is located between two adjacent stator windings; or the stator windings and the rotor winding are stacked.

[0024] In some embodiments, the stator windings are formed in a planar winding manner, and the stator windings and the rotor winding are stacked.

[0025] In some embodiments, the rotor body comprises a plurality of sub-rotor bodies, and each of the sub-rotor bodies is circumferentially disposed with a rotation center line therebetween; and / or,

[0026] the stator body comprises a plurality of sub-stator bodies, and each of the sub-stator bodies is circumferentially disposed with the rotation center line therebetween.

[0027] In a second aspect, the embodiments of the present application provide a device with a rotary transformer.

[0028] The device with the rotary transformer provided by the embodiments of the present application has higher output efficiency on the basis of the rotary transformer.

[0029] In some embodiments, the device is an electric drive system, and the electric drive system comprises a motor and the rotary transformer, and a rotor body of the rotary transformer is connected with a rotor of the motor.

[0030] In a third aspect, the embodiments of the present application provide an electric drive device, which comprises the rotary transformer.

[0031] The electric drive device provided by the embodiments of the present application has higher output efficiency on the basis of the rotary transformer. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description only constitute some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0033] Fig. 1 is a structural schematic diagram of a rotary transformer of the prior art;

[0034] Fig. 2 is a schematic diagram of the rotary transformer in Fig. 1 under simulation;

[0035] Fig. 3 is a structural schematic diagram of a vehicle provided by an embodiment of the present application;

[0036] Fig. 4 is a sectional structural schematic diagram of a rotary transformer provided by an embodiment one of the present application;

[0037] Fig. 5 is a sectional structural schematic diagram of a rotary transformer provided by an embodiment two of the present application;

[0038] Fig. 6 is a sectional structural schematic diagram of a rotary transformer provided by an embodiment three of the present application;

[0039] Fig. 7 is a sectional structural schematic diagram of a rotary transformer provided by an embodiment four of the present application;

[0040] Fig. 8 is a sectional structural schematic diagram of a rotary transformer provided by an embodiment five of the present application;

[0041] Fig. 9 is a sectional structural schematic diagram of a rotary transformer provided by an embodiment six of the present application;

[0042] Fig. 10 is a sectional structural schematic diagram of a rotary transformer provided by an embodiment seven of the present application;

[0043] Fig. 11 is a sectional structural schematic diagram of a rotary transformer provided by an embodiment eight of the present application;

[0044] Fig. 12 is a sectional structural schematic diagram of a rotary transformer provided by an embodiment nine of the present application;

[0045] Fig. 13 is a sectional structural schematic diagram of a rotary transformer provided by an embodiment ten of the present application;

[0046] Fig. 14 is a structural schematic diagram of a rotary transformer provided by an embodiment eleven of the present application;

[0047] Fig. 15 is a schematic diagram of the rotary transformer provided by an embodiment one of the present application under simulation;

[0048] Fig. 16 is a schematic diagram of the rotary transformer provided by an embodiment three of the present application under simulation;

[0049] FIG. 17 is a schematic diagram of a resolver in simulation according to an embodiment of the present application.

[0050] In the drawings: 1, fixed part; 2, rotating part; 3, winding; 4, structural air gap; 10000, vehicle; 1000, battery; 2000, controller; 3000, motor; 100, resolver; 10, stator part; 11, stator body; 12, stator winding; 111, first stator subpart; 112, second stator subpart; 10a, sub stator body; 20, rotor part; 21, rotor body; 22, rotor winding; 211, first rotor subpart; 212, second rotor subpart; 21a, first end; 21b, second end; 20a, sub rotor body; 30, accommodating cavity; 41, first structural air gap; 42, second structural air gap; 43, magnetic conductor; 50, rotation axis; X, tangential direction; Y, normal direction; Z, extension direction. DETAILED DESCRIPTION

[0051] Embodiments of the present application are described in detail below with reference to examples illustrated in the accompanying drawings, in which the same or similar components have the same or similar designations throughout the various figures. The embodiments described below are examples intended to explain the present application, and are not to be understood as limiting the present application.

[0052] In the description of the present application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only intended to facilitate the description of the present application and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0053] In addition, the terms "first", "second", "third", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified.

[0054] In this application, unless otherwise clearly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and other terms should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrated; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0055] First of all, it should be pointed out that Figs. 2, 15, 16 and 17 are electromagnetic field strength simulation diagrams of the resolver.

[0056] In the electromagnetic field strength simulation diagram, the color bar on the left side represents the distribution of electromagnetic field strength, with units of Weber, ranging from -0.0000000 to 0.0000211, and the color changes from blue (low intensity) to red (high intensity). Specifically, along the length direction of the color bar, the color bar gradually changes from dark blue, light blue, green, yellow, orange, and red from the lower end to the upper end.

[0057] In the electromagnetic field strength simulation diagram, the right part represents the electromagnetic field strength simulation situation of the resolver. The color change rule in the structural air gap 4 shown in Fig. 2 and the first structural air gap 41 and the second structural air gap 42 shown in Figs. 15, 16 and 17 is that along the direction from the inner end of the structural air gap 4, the first structural air gap 41 and the second structural air gap 42 to the outer end of the structural air gap 4, the first structural air gap 41 and the second structural air gap 42, the color gradually changes from red, orange, yellow, green, light blue, and dark blue. Correspondingly, the magnetic lines of force located on the outside of the resolver are blue, and the magnetic lines of force located on the inside of the resolver are red.

[0058] The resolver is a kind of sensor with a structure similar to that of a motor. As shown in Fig. 1, the resolver includes a fixed part 1 and a rotating part 2 coaxially rotating with the fixed part 1. Specifically, when using non-contact assembly, 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.

[0059] However, with reference to Fig. 1, the magnetic lines of force generated by the structure air gap 4 in the above structure are similar to the quarter circle structure, the magnetic field strength generated by the edge magnetic flux of the structure air gap 4 can be divided into a normal magnetic field component Hy and a tangential magnetic field component Hx, and the smaller the proportion of the tangential magnetic field component Hx, the greater the proportion of the normal magnetic field component Hy, wherein the normal magnetic field component Hy plays a leading role in eddy current loss. Referring to Fig. 2, which is a schematic diagram of a rotary transformer under simulation, it can be seen from the figure that the edge magnetic flux generated by the structure air gap 4 generates a large eddy current loss, 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, as can be seen from the figure, 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.

[0060] Therefore, the present application provides a rotary transformer, which forms a first structure air gap between a stator body and a rotor body, additionally forms a second structure air gap on the stator body, and makes the second structure air gap and the first structure air gap both in the normal direction of the rotor winding, so that the normal magnetic field component generated by the edge magnetic flux at the second structure air gap and the normal magnetic field component generated by the edge magnetic flux at the first structure air gap can be offset, thereby realizing the closure of the magnetic lines of force in the accommodation cavity along the tangential direction of the rotor winding to reduce the eddy current loss, increase the effective utilization area of the rotor winding, and make the current distribution on the rotor winding more uniform.

[0061] The device provided by the embodiment of the present application has the rotary transformer 100, and the device can be a generator, a motor, a turbine, a radar, a camera, an underwater robot, and the like.

[0062] Of course, the rotary transformer 100 provided by the present application is not only limited to the above-mentioned devices, but can also be applied to all devices using the rotary transformer 100.

[0063] The rotary transformer 100 provided by the present application can also be applied to electrically driven equipment, including vehicles, portable devices, ships, spacecraft, electric power tools, and the like, wherein the vehicles can be fuel cars, gas cars, or new energy cars, and the new energy cars can be pure electric cars, hybrid cars, or extended range cars, and the like; the spacecraft includes airplanes, rockets, space shuttles, and spacecraft, and the like; the electric power tools include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, electric plane toys, and the like; the electric power tools include metal cutting electric power tools, grinding electric power tools, assembly electric power tools, and iron electric power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planes, and the like.

[0064] Of course, the resolver 100 provided by the present application is not only limited to the electrically driven device described above, but can also be applied to all electrically driven devices using the resolver 100, but for the sake of brevity of description, the following embodiments are described by taking an electric vehicle as an example.

[0065] For example, please refer to FIG. 3, which is a structural schematic diagram of a vehicle 10000 according to an embodiment of the present application. The vehicle 10000 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 a range extended vehicle, etc. The vehicle 10000 can be provided with a battery 1000, a controller 2000, a motor 3000, and a resolver 100 inside. The controller 2000 is used to control the power supply of the motor 3000 by the battery 1000, and the resolver 100 is used to electrically connect with the motor 3000.

[0066] Please refer to FIG. 4 and FIG. 5, the resolver 100 provided by the present application includes a rotor part 20 and a stator part 10.

[0067] The rotor part 20 includes a rotor body 21 rotating around its own axis and a rotor winding 22 rotating with the rotor body 21 around the axis, and the rotor winding 22 is formed in a planar winding manner and has a tangential direction X and a normal direction Y perpendicular to each other.

[0068] The stator part 10 includes a stator body 11 surrounding the rotor body 21 to form an accommodating cavity 30, and a stator winding 12 arranged in the accommodating cavity 30.

[0069] The rotor winding 22 is arranged in the accommodating cavity 30, and a first structural air gap 41 is formed between the rotor body 21 and the stator body 11. The stator body 11 is formed with a second structural air gap 42, and 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.

[0070] It can be understood that the stator part 10 is the part of the resolver 100 that remains relatively stationary during operation, and the rotor part 20 is the part of the resolver 100 that rotates relatively during operation. At the same time, the relative arrangement of the stator part 10 and the rotor part 20 is adjusted according to actual needs. For example, the stator part 10 is coaxially arranged with the rotation center axis of the rotor part 20, and the stator part 10 is arranged on the outer circumferential side of the rotor part 20. The structure of this resolver 100 is similar to the structure arrangement of an internal rotor motor. Alternatively, the rotor part 20 is coaxially arranged with the center axis of the stator part 10, and the rotor part 20 is arranged on the outer circumferential side of the stator part 10. The structure of this resolver 100 is similar to the structure arrangement of an external rotor motor.

[0071] Meanwhile, the stator part 10 and the rotor part 20 are assembled in a non-contact manner, and thus a first structural air gap 41 is formed between the stator part 10 and the rotor part 20. The first structural air gap 41 is inevitable in the non-contact assembly of the stator part 10 and the rotor part 20, that is, the rotor part 20 can rotate relative to the stator part 10 only on the basis of the first structural air gap 41.

[0072] The rotor body 21 can be made of silicon steel sheets, ferrite, microcrystalline, ultra-microcrystalline, or permalloy, and is connected to the rotating shaft 50. According to actual use requirements, the rotor body 21 can be arranged in an extension along the axial direction of the rotating shaft 50, or the rotor body 21 can also be arranged in an extension along the radial direction of the rotating shaft 50.

[0073] The rotor winding 22 includes, but is not limited to, solid conductors, Litz wires, copper foils, and flexible circuit board windings. The rotor winding 22 is connected to the rotor body 21 to enable the rotor winding 22 to rotate with the rotor body 21.

[0074] Planar winding is a layout mode of electromagnetic windings, in which winding coils are 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 intersected. The rotor winding 22 formed by planar winding has the advantages of compact structure, good electromagnetic performance, and convenient manufacturing.

[0075] After the rotor winding 22 is formed by planar winding, a flat plate-like structure is formed. The tangential direction X of the rotor winding 22 is the X-axis direction in the figure, which is parallel to the plane of the flat plate-like structure. The normal direction Y of the rotor winding 22 is the Y-axis direction in the figure, which is perpendicular to the plane of the flat plate-like structure.

[0076] It should be noted that the normal direction Y of the rotor winding 22 should be the same as the extension arrangement direction of the rotor body 21. For example, when the rotor body 21 is arranged in an extension along the axial direction of the rotating shaft 50, the normal direction Y of the rotor winding 22 is parallel to the axial direction of the rotating shaft 50. For another example, when the rotor body 21 is arranged in an extension along the radial direction of the rotating shaft 50, the normal direction Y of the rotor winding 22 is perpendicular to the axial direction of the rotating shaft 50.

[0077] The stator body 11 can be made of silicon steel sheets, ferrite, microcrystalline, ultra-microcrystalline, or permalloy, and the stator body 11 and the rotor body 21 are surrounded to form the accommodation cavity 30.

[0078] For example, as shown in FIG. 4, in the axial cross-sectional direction of the rotary transformer 100, the rotor body 21 has a similar pipe column structure, and the stator body 11 has a similar concave structure. The rotor body 21 and the stator body 11 are surrounded to form the accommodation cavity 30.

[0079] For example, as shown in FIG. 8, 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, and the rotor body 21 and the stator body 11 are similarly surrounded to form the accommodation cavity 30.

[0080] The stator winding 12 includes, but is not limited to, solid wire, litz wire, copper foil, and flexible circuit board winding. The stator winding 12 is connected to the stator body 11, and the stator winding 12 and the rotor winding 22 remain relatively stationary.

[0081] The rotor winding 22 and the stator winding 12 are both placed in the accommodation cavity 30, and the stator winding 12 can be formed in the accommodation space by surrounding winding, that is, the coils of the stator winding 12 are coaxially wound with the center axis of the rotor body 21 as the center, of course, the stator winding 12 can also be formed by planar winding.

[0082] The second structure air gap 42 should be a through hole or a through slot structure through 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 structure air gap 42.

[0083] For example, in the axial cross-sectional direction of the rotary transformer 100, the number of second structure air gaps 42 is one, and the stator body 11 divided by the second structure air gap 42 should include a first part arranged along the tangential direction X and a second part in the shape of L; or the number of second structure air gaps 42 is two, and the stator body 11 divided by the second structure air gap 42 should include two first parts arranged along the tangential direction X and spaced apart, and a second part between the two first parts; or the number of second structure air gaps 42 is multiple, and the stator body 11 divided by the second structure air gap 42 should include two first parts arranged along the tangential direction X and spaced apart, each first part is further divided into multiple segments by the remaining second structure air gap 42, and the second part between the two first parts is also divided into at least two segments by the remaining second structure air gap 42.

[0084] Opposite to the normal direction Y of the rotor winding 22 is the tangential direction X of the rotor winding 22, which is the direction parallel to the plane after plane winding. Since the normal magnetic field component of the magnetic field strength generated by the edge magnetic flux at the structural air gap plays a dominant role in eddy current loss, the second structural air gap 42 should be located in the normal direction Y of the rotor winding 22, i.e., 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 can be parallel or at an angle to the normal direction Y or parallel or at an angle to the tangential direction Z, and the rest of the structural air gaps that are not coplanar with the plane where the rotor winding 22 is located are also referred to as the structural air gaps located in the normal direction Y of the rotor winding 22, i.e., the structural air gaps located in the normal direction Y of the rotor winding 22 have a normal magnetic field component, while the normal magnetic field component of the structural air gaps located in the tangential direction X of the rotor winding 22 is almost zero.

[0085] In the axial cross-section of the resolver 100, the stator body 11 has at least three facing sides relative to the rotor winding 22 in the normal direction Y of the rotor winding 22, i.e., the stator body 11 is semi-openly wrapped around the rotor winding 22, and therefore, the second structural air gap 42 can be formed on any one or several of the at least three facing sides of the stator body 11.

[0086] For example, as shown in FIG. 4, in the axial cross-section of the resolver 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 extension directions of the two first structural air gaps 41 are the same as the normal direction Y of the rotor winding 22, and the extension directions of the two second structural air gaps 42 are also the same as the normal direction Y of the rotor winding 22.

[0087] For example, as shown in FIG. 5, in the axial cross-section of the resolver 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 extension directions of the two first structural air gaps 41 are the same as the normal direction Y of the rotor winding 22, and the extension directions of the two second structural air gaps 42 are the same as the tangential direction X of the rotor winding 22, but the two second structural air gaps 42 are not coplanar with the plane where the rotor winding 22 is located, and at this time, the second structural air gaps 42 are also referred to as the structural air gaps located in the normal direction Y of the rotor winding 22.

[0088] Please refer to FIG. 15, which is a schematic diagram of the resolver 100 in simulation according to an embodiment of the present application. As shown in the diagram, the edge magnetic flux of the second-structure air gap 42 and the edge magnetic flux of the first-structure air gap 41 cancel each other out, and the current distribution on the rotor winding 22 is more dispersed, so that 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.

[0089] The resolver 100 according to the present application additionally forms the second-structure air gap 42 on the stator body 11, and the second-structure air gap 42 and the first-structure air gap 41 are both located in the normal direction Y of the rotor winding 22, so that the normal magnetic field component generated by the edge magnetic flux at the second-structure air gap 42 cancels out the normal magnetic field component generated by the edge magnetic flux at the first-structure air gap 41, thereby realizing the magnetic force lines in the accommodation cavity 30 to close along the tangential direction X of the rotor winding 22. Compared with the resolver 100 with only the first-structure air gap 41, the double-structure air gap can effectively reduce the eddy current loss and improve the problem of concentrated distribution of the winding current 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 further improving the energy transmission efficiency of the resolver 100.

[0090] Please refer to FIG. 4, FIG. 5 and FIG. 7. In some embodiments, the stator body 11 includes a first stator sub-portion 111 and a second stator sub-portion 112 which forms a concave cavity in combination with the first stator sub-portion 111, wherein one end of the second stator sub-portion 112 forms the first-structure air gap 41 with the outer wall of the rotor body 21, and the other end of the second stator sub-portion 112 forms the second-structure air gap 42 with the outer wall of the first stator sub-portion 111.

[0091] It can be understood that, in order to meet the structure of surrounding the rotor body 21 to form the accommodation cavity 30, the first stator sub-portion 111 and the second stator sub-portion 112 form a U-shaped structure or a U-like structure. For example, the number of the second stator sub-portion 112 is two, the two second stator sub-portions 112 are arranged along the tangential direction X, and the first stator sub-portion 111 is arranged along the normal direction Y. Alternatively, the number of the second stator sub-portion 112 is one, the second stator sub-portion 112 is arranged along the tangential direction X, and the first stator structure 200 is L-shaped or L-like, i.e., the first stator structure 200 includes a first portion arranged along the tangential direction X and a second portion connected with the first portion and arranged along the normal direction Y.

[0092] The end of the second stator sub-portion 112 away from the first stator sub-portion 111 should be non-contact assembled with the rotor body 21 to form the first-structure air gap 41.

[0093] There are two cases for the second structural air gap 42 formed between the one end of the second stator sub-part 112 towards the first stator sub-part 111 and the outer wall of the first stator sub-part 111.

[0094] Case one, as shown in FIG. 4, the extending direction of the second structural air gap 42 is parallel to the normal direction Y; case two, as shown in FIG. 5, the extending direction of the second structural air gap 42 is parallel to the tangential direction X.

[0095] Optionally, as shown in FIG. 4, the number of the first structural air gaps 41 is two, and the number of the second structural air gaps 42 is also two, and the extending direction of the two second structural air gaps 42 is parallel to the normal direction Y, thus, the normal magnetic field components generated by the edge magnetic flux of the two first structural air gaps 41 and the normal magnetic field components generated by the edge magnetic flux of the two second structural air gaps 42 are in opposite directions and can be offset each other.

[0096] In summary, according to the actual use requirements, adjusting the number of the second stator sub-parts 112 in the stator main body 11, that is, the number and the setting position of the second structural air gaps 42, can also reduce or offset the normal magnetic field components generated by the edge magnetic flux of the first structural air gaps 41, and further make the current distribution on the surface of the rotor winding 22 more uniform, reduce the eddy current loss on the surface of the rotor winding 22, and reduce the probability of local serious heating of the rotor winding 22.

[0097] Please refer to FIG. 7, in some embodiments, at least one second stator sub-part 112 is further provided with a plurality of second structural air gaps 42; and / or, the first stator sub-part 111 is further provided with a plurality of second structural air gaps 42.

[0098] It can be understood that the second structural air gaps 42 can also be distributed on the first stator sub-part 111; or, distributed on the second stator sub-part 112; or, distributed on the first stator sub-part 111 and the second stator sub-part 112.

[0099] When the second structural air gaps 42 are distributed on the first stator sub-part 111, that is, the second structural air gaps 42 divide the integral first stator sub-part 111 into a plurality of parts; or, when the second structural air gaps 42 are distributed on the second stator sub-part 112, the second structural air gaps 42 divide the integral second stator sub-part 112 into a plurality of parts.

[0100] For example, as shown in FIG. 17, which is a schematic diagram of the resolver 100 provided by the fourth embodiment of the present application in simulation, the second structure air gap 42 is additionally formed on the second stator sub-portion 112 in addition to being arranged between the end of the second stator sub-portion 112 and the outer wall of the first stator sub-portion 111. As can be seen from the diagram, the magnetic lines of force inside the accommodation cavity 30 are closed along the tangential 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, so that the current distribution on the surface of the rotor winding 22 is uniform. As can be seen from the diagram, the high red phenomenon occurs at the opposite ends of the rotor winding 22 in the tangential direction X, which also indicates that the current distribution on the surface of the rotor winding 22 is more dispersed, and the effective utilization area is larger.

[0101] In this way, the number of the second structure air gaps 42 can be increased according to actual use requirements, which can effectively improve the uneven current distribution on the surface of the rotor winding 22, and increase the effective utilization area.

[0102] Referring to FIG. 4, in some embodiments, the extension direction of the first structure air gap 41 and the extension direction of the second structure air gap 42 are both the same as the normal direction Y, and the distance d1 between the first structure air gap 41 and any one of the second structure air gaps 42 is less than the width w of the accommodation cavity 30 in the tangential direction X.

[0103] It can be understood that the above-mentioned second structure air gap 42 should be distributed on the second stator sub-portion 112, or on the portion of the L-shaped first stator sub-portion 111 in the tangential direction X, so that the extension direction in which the second structure air gap 42 is arranged is the same as the normal direction Y.

[0104] The distance d1 between the first structure air gap 41 and any one of the second structure air gaps 42 can be the length of the current second stator sub-portion 112 in the tangential direction X or the length of the portion of the L-shaped first stator sub-portion 111 in the tangential direction X after being divided. Alternatively, when the number of the second structure air gaps 42 is multiple, the distance d1 between the first structure air gap 41 and any one of the second structure air gaps 42 can also be the length of the portion of the current second stator sub-portion 112 in the tangential direction X after being divided.

[0105] The width w of the accommodation 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 accommodation cavity 30 in the tangential direction X.

[0106] For example, as shown in FIG. 4, the stator body 11 includes the first stator sub-portion 111 and two second stator sub-portions 112, then the interval 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-portion 112 in the tangential direction X, and the width w of the accommodation cavity 30 in the tangential direction X is the width of the current magnetic core window. Since the second stator sub-portion 112 is not divided by the second structural air gap 42, then the ratio of d1 to w can be infinitely close to 1, as long as the gap of the first structural air gap 41 and the gap of the second structural air gap 42 are small enough.

[0107] For example, as shown in FIG. 7, the stator body 11 includes the first stator sub-portion 111 and two second stator sub-portions 112, the two second stator sub-portions 112 form the second structural air gap 42 with the outer wall of the first stator sub-portion 111 at the end of the first stator sub-portion 111, and a second structural air gap 42 is also formed on the second stator sub-portion 112, and the second stator sub-portion 112 is equally divided into two parts, then the interval 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 current second stator sub-portion 112 in the tangential direction X, and the width w of the accommodation cavity 30 in the tangential direction X is the width of the current magnetic core window. At this time, the ratio of d to w is 0.5, or close to 0.5.

[0108] In summary, the ratio of d1 to w can be between 0.1 and 1, for example, the ratio of d1 to w can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, etc.

[0109] Please refer to FIG. 4, FIG. 6 and FIG. 7, in some embodiments, in the normal direction Y, the distance d2 between the opposite ends of the rotor winding 22 to the inner wall of the accommodation cavity 30 and the width w of the accommodation cavity 30 in the tangential direction X also have a certain proportional relationship, for example, the ratio of d2 to w can be between 0.1 and 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.

[0110] Alternatively, the middle region of the accommodation cavity 30 at the rotor winding 22, that is, the distance d2 between the opposite ends of the rotor winding 22 to the inner wall of the accommodation cavity 30 is equal.

[0111] Please refer to FIG. 6, in some embodiments, at least one second structural air gap 42 is provided with a magnetic conductor 43, and the magnetic permeability of the magnetic conductor 43 is lower than that of the stator body 11.

[0112] It can be understood that after the second structure air gap 42 is formed on the stator body 11, theoretically, the magnetic permeability of the first stator sub 111 and the magnetic permeability of the second stator sub 112 are the same, and thus the magnetic permeability of the magnetic conductor 43 is smaller than that of the stator sub. Of course, the stator body 11 can also be composed of stator subs with different magnetic permeabilities, and thus the magnetic permeability of the magnetic conductor 43 is smaller than that of the stator sub, or smaller than that of both stator subs.

[0113] Here, the magnetic conductor 43 can 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, etc.

[0114] In addition, the magnetic conductor 43 can be arranged in the second structure air gap 42 in a fully filled manner, that is, there is no gap between the outer wall of the magnetic conductor 43 and the inner wall of the second structure air gap 42 within the allowable error range. Alternatively, the magnetic conductor 43 can be arranged in the second structure air gap 42 in a partially filled manner, that is, after the magnetic conductor 43 is arranged, there is still a gap between the outer wall of the magnetic conductor 43 and the inner wall of the second structure air gap 42.

[0115] The gap of the first structure air gap 41 is a, and the gap of the second structure air gap 42 is b, both of which are in mm. The ratio of a to b is in the range of 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 arranged in the second structure air gap 42, the following relationship exists: b = μra, where μr is the magnetic permeability of the magnetic conductor 43.

[0116] For example, as shown in FIG. 16, which is a schematic diagram of the simulation of the resolver 100 provided in Embodiment Three, it can be known from the diagram 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 appear to be offset, and the current distribution on the rotor winding 22 is more dispersed, so that the overall rotor winding 22 is red, which also indicates that the effective utilization area of the rotor winding 22 is higher and the current distribution is more uniform.

[0117] In this way, the arrangement of the magnetic conductor 43 in the second structure air gap 42 can enrich the implementation mode of reducing the loss of the rotor winding 22, and the magnetic conductor 43 can also be used to limit the relative movement of the stator subs of the stator body 11, which is helpful for the fixed installation of the stator 10.

[0118] Please refer to FIGS. 4 to 8. In some embodiments, the rotor body 21 includes a first rotor sub 211 arranged to extend along the normal direction Y, and the first rotor sub 211 and the stator body 11 form a first structure air gap 41 therebetween.

[0119] It can be understood that the first rotor sub-part 211 is the main part of the rotor body 21 and the part connected with the external rotating shaft or input shaft, and the first rotor sub-part 211 is arranged in an I shape or 1 shape in the normal direction Y, and the stator body 11 and the outer wall or inner wall of the first rotor sub-part 211 form the first structural air gap 41.

[0120] Alternatively, as shown in FIG. 4, the stator body 11 includes a first stator sub-part 111 and two second stator sub-parts 112, the same end of the two second stator sub-parts 112 and the outer wall of the first rotor sub-part 211 form the first structural air gap 41, the other end of the two second stator sub-parts 112 and the outer wall of the first stator sub-part 111 form the second structural air gap 42, and 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 stator winding 12 and the rotor winding 22 are symmetrically arranged about the midpoint of the first stator sub-part 111, in this way, the structure of the rotary transformer 100 is mirror image arranged, then the normal magnetic field component generated by the edge magnetic flux at the second structural air gap 42 and the normal magnetic field component generated by the edge magnetic flux at the first structural air gap 41 are completely offset, further, the eddy current loss of the rotor winding 22 is reduced.

[0121] In this way, the first rotor sub-part 211 in an I shape or 1 shape can minimize the additional weight of the rotor body 21, the rotor body 21 can be closer to the rotating center axis, and the centrifugal force can be effectively reduced, which is suitable for high-speed rotation.

[0122] Please refer to FIG. 8 and FIG. 9, in some embodiments, the rotor body 21 further includes a second rotor sub-part 212 arranged on the first rotor sub-part 211 and extending outward along the tangential direction X, and the second rotor sub-part 212 and the stator body 11 form the first structural air gap 41.

[0123] It can be understood that the second rotor sub-part 212 is the part of the rotor body 21 that can be adapted to the stator structure 200, and after adding the second rotor sub-part 212 on the first rotor sub-part 211, the overall structure of the rotor body 21 changes accordingly.

[0124] For example, as shown in FIG. 8, two second rotor sub-parts 212 are arranged 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 in a U shape or a U-like shape.

[0125] For example, as shown in FIG. 9, one second rotor sub-part 212 is arranged 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 in an L shape or an L-like shape.

[0126] Please refer to FIG. 10, in some embodiments, the first rotor sub-portion 211 has a first end 21a and a second end 21b oppositely arranged along the normal direction Y, and the end face of the first end 21a and / or the end face of the second end 21b is higher than the end face of the stator main body 11 in the normal direction Y.

[0127] It can be understood that the end face of the first end 21a of the first rotor sub-portion 211 in the normal direction Y is higher than the end face of the stator main body 11 in the normal direction Y; or, the end face of the second end 21b of the first rotor sub-portion 211 in the normal direction Y is higher than the end face of the stator main 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-portion 211 in the normal direction Y are both higher than the end face of the stator main body 11 in the normal direction Y.

[0128] In this way, the rotor main body 21 is arranged to extend in the normal direction Y, which can further reduce the structural air gap leakage flux to the external rotating shaft or the input shaft.

[0129] Please refer to FIG. 4 to FIG. 13, in some embodiments, the rotary transformer 100 comprises a rotating shaft 50, and the first rotor sub-portion 211 is arranged to extend along the axial direction of the rotating shaft 50; or, the first rotor sub-portion 211 is arranged to extend along the radial direction of the rotating shaft 50.

[0130] It can be understood that the rotating shaft 50 is a shaft structure for driving the first rotor sub-portion 211 to rotate around the shaft. Thus, the arrangement of the first rotor sub-portion 211 on the rotating shaft 50 includes the following two cases:

[0131] For example, as shown in FIG. 10, the first rotor sub-portion 211 is arranged to extend along the axial direction of the rotating shaft 50, and here the axial direction of the rotating shaft 50 is parallel to the normal direction Y.

[0132] For example, as shown in FIG. 13, the first rotor sub-portion 211 is arranged to extend along the radial direction of the rotating shaft 50, and here the radial direction of the rotating shaft 50 is parallel to the normal direction Y.

[0133] In this way, the assembly mode of the first rotor sub-portion 211 and the rotating shaft 50 can be adjusted according to actual use requirements, so as to improve the structural adaptability of the rotary transformer 100.

[0134] Please refer to FIG. 10 and FIG. 11, in some embodiments, the stator winding 12 is formed in a wrap-around winding mode, and the rotor winding 22 is located between two adjacent stator windings 12; or, the stator winding 12 and the rotor winding 22 are arranged in a stacked manner.

[0135] It can be understood that the wrap-around winding mode is a layer-by-layer winding from inside to outside with the rotation center line of the rotor portion 20 as the winding center. Thus, in the normal direction Y, the stator winding 12 can be composed of multiple layers of coils.

[0136] The arrangement of the rotor winding 22 and the stator winding 12 in the accommodation cavity 30 can be that the rotor winding 22 is located 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 accommodation cavity 30, and the rotor winding 22 is located on the other side of the accommodation cavity 30, and the two are stacked.

[0137] Referring to FIG. 12, in some embodiments, the stator winding 12 is formed in a planar winding manner, and the stator winding 12 and the rotor winding 22 are stacked.

[0138] It can be understood that the stator winding 12 can also be formed in a planar winding manner, that is, the forming manner is the same as that of the rotor winding 22, and after winding is completed, the stator winding 12 is located on one side of the accommodation cavity 30, and the rotor winding 22 is located on the other side of the accommodation cavity 30, and the two are stacked.

[0139] Referring to FIG. 14, in some embodiments, the rotor body 21 includes a plurality of sub-rotor bodies 20a, and each sub-rotor body 20a is arranged around the rotation center line at intervals; and / 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.

[0140] It can be understood that there is a gap between each sub-rotor body 20a, rather than a ring-shaped whole, and similarly, there is also a gap between each sub-stator body 10a, which is also a ring-shaped whole.

[0141] Of course, the two structures can be adjusted in form, 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 ring 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 ring 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, each sub-stator body 10a is arranged around the rotation center line at intervals, and each sub-stator body 10a corresponds to a sub-rotor body 20a.

[0142] In this way, the magnetic amount of the stator body 11 and the rotor body 21 can be correspondingly reduced, and the overall weight of the rotary transformer 100 can be further reduced.

[0143] Please refer to Figure 4, in one specific embodiment, the application provides a resolver 100, which includes a rotor part 20 and a stator part 10.

[0144] The rotor part 20 includes a rotor body 21 rotating around its own axis and a rotor winding 22 rotating with the rotor body 21 around the axis, the rotor winding 22 is formed in a planar winding mode and has a tangential direction X and a normal direction Y perpendicular to each other;

[0145] The stator part 10 includes a stator body 11 surrounding the rotor body 21 to form a receiving cavity 30 and a stator winding 12 arranged in the receiving cavity 30;

[0146] Wherein, the rotor winding 22 is arranged in the receiving cavity 30, the first structural air gap 41 is formed between the rotor body 21 and the stator body 11, the second structural air gap 42 is formed on the stator body 11, and the first structural air gap 41 and the second structural air gap 42 are located on the normal direction Y of the rotor winding 22.

[0147] The stator body 11 includes a first stator sub-part 111 and two second stator sub-parts 112 surrounding the first stator sub-part 111 to form a recess, wherein one end of the second stator sub-part 112 forms the 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 the second structural air gap 42 with the outer wall of the first stator sub-part 111.

[0148] The following is characterized by simulation test.

[0149] Embodiment one

[0150] The rotor body 21 of the resolver 100 is I-shaped, the stator body 11 includes a first stator sub-part 111 and two second stator sub-parts 112, and the end of the second stator sub-part 112 and the outer wall of the first stator sub-part 111 form the second structural air gap 42, and the extension direction of the first structural air gap 41 and the extension direction of the second structural air gap 42 are the same as the normal direction Y. At the same time, 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, d2=0.26w.

[0151] Embodiment two

[0152] The rotor body 21 of the resolver 100 is in the shape of I, the stator body 11 includes a first stator sub-portion 111 and two second stator sub-portions 112, the end portions of the two second stator sub-portions 112 and the outer wall of the first stator sub-portion 111 form a second structural air gap 42, the extension direction of the first structural air gap 41 and the extension direction of each second structural air gap 42 are the same as the normal direction Y, and a magnetic conductor 43 is arranged at each of the two second structural air gaps 42. At the same time, the magnetic permeability μr of the magnetic conductor 43 is 5, the gap a of the first structural air gap 41 is b, b = 5a, d1 = 0.85w, and d2 = 0.26w.

[0153] Example Three

[0154] The rotor body 21 of the resolver 100 is in the shape of I, the stator body 11 includes a first stator sub-portion 111 and two second stator sub-portions 112, the end portions of the two second stator sub-portions 112 and the outer wall of the first stator sub-portion 111 form a second structural air gap 42, and an additional second structural air gap 42 is formed on each of the two second stator sub-portions 112, and the extension direction of the first structural air gap 41 and the extension direction of each second structural air gap 42 are the same as the normal direction Y. At the same time, the gap a of the first structural air gap 41 is b, d1 = 0.5w, and d2 = 0.26w.

[0155] Comparative Example 1

[0156] The rotor portion of the resolver is in the shape of I, the stator portion is in the shape of U, the stator portion is assembled with the rotor portion in a non-contact manner and forms 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 example, and the size specifications, the number of windings, and the winding arrangement position of the resolver in Comparative Example 1 are the same as those of the resolver 100 in each example, and the only variable is that the stator portion in Comparative Example 1 does not form a second structural air gap 42.

[0157] According to the structural models provided by each of the above examples and Comparative Example 1, under the same experimental conditions, the relevant parameters in Table 1 and the corresponding magnetic field simulation results can be obtained.

[0158] Wherein, Lp is the primary side self-inductance of the resolver 100, M is the secondary side mutual inductance of the resolver 100, Ls is the secondary side self-inductance of the resolver 100, Rp is the parasitic resistance of the primary side of the resolver 100, and Rs is the parasitic resistance of the secondary side of the resolver 100.

[0159] As can be seen from the table, the parasitic resistance of the resolver 100 in each embodiment is smaller to different degrees, so that the magnetic field component of the rotor winding 22 in the normal direction Y is also reduced, and the eddy current loss is also reduced accordingly.

[0160] Furthermore, the current density in each embodiment is smaller than that in the comparative example 1, which indicates that the current distribution on the plane of the rotor winding 22 in each embodiment is more uniform, and the effective utilization area is larger.

[0161] Specifically, as can be seen from FIG. 2, FIG. 15 to FIG. 17, the magnetic force lines in the magnetic core window in each embodiment are closed along the tangential direction of the rotor winding axis, and the magnetic force lines tend to be parallel to the tangential plane of the rotor winding 22.

[0162] In a second aspect, the embodiments of the present application provide a device with the resolver 100, which comprises the resolver 100.

[0163] The device with the resolver 100 provided by the present application has higher output efficiency on the basis of the resolver 100.

[0164] Specifically, the device is an electric drive system, which comprises a motor and the resolver 100, and the rotor body 21 of the resolver 100 is connected with the rotor of the motor.

[0165] In a third aspect, the embodiments of the present application provide an electric drive device, which comprises the resolver 100.

[0166] The electric drive device provided by the present application has higher output efficiency on the basis of the resolver 100.

[0167] The above are only the preferred embodiments of the present application, and are not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

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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