Hub motor structure and vehicle

Abstract

The utility model relates to a hub motor structure and a vehicle. The hub motor structure comprises a rotor support, a brake drum and a driving member. The rotor support is used for being connected with a hub, and a brake cavity is formed in the axial side of the rotor support. The driving piece is connected to the rotor support and used for driving the rotor support to drive the hub to rotate; the brake drum is arranged in the brake cavity and connected to the rotor support, and the brake drum is used for being matched with the brake shoe to brake the hub. The brake cavity is formed in the axial side of the rotor support, the brake drum is arranged in the brake cavity, the occupied space of the brake drum can be saved, due to the fact that the brake drum is connected with the rotor support, when the hub rotates along with the rotor support, the brake drum can rotate synchronously, the brake drum can be braked through the brake shoes, and the service life of the brake drum is prolonged. Further, the hub is driven to stop rotating; and the brake drum is arranged in the brake cavity, so that the axial size of the whole hub motor structure can be reduced, the arrangement is convenient, and meanwhile, the transmission efficiency and the brake efficiency are not influenced.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle manufacturing, and in particular to a wheel hub motor structure and a vehicle. Background Art

[0002] Compared with traditional cars, electric cars have the advantages of energy saving and environmental protection, making them the mainstream of future development in the automotive field. Electric cars can be divided into two categories according to the structure of the powertrain: centralized drive and distributed wheel-side drive. The main structural feature of distributed wheel-side drive electric cars is that the drive motor is directly installed in or near the drive wheel, which has outstanding advantages such as short drive transmission chain, high efficiency and compactness.

[0003] In the distributed drive structure, the brake and the drive motor are independent of each other and connected by a drive shaft. However, the drive shaft connecting the brake assembly and the drive motor takes up a large space and has a complex layout, which affects the vehicle's endurance.

[0004] In view of this, this application is hereby filed. Utility Model Content

[0005] The present application provides a wheel hub motor structure and a vehicle to solve the technical problems of the existing wheel hub motor structure.

[0006] The first aspect of the utility model provides a wheel hub motor structure, including a rotor support, a brake drum and a driving member; the rotor support is used to connect the wheel hub, and the rotor support forms a brake cavity on one axial side; the driving member is connected to the rotor support, and is used to drive the rotor support to drive the wheel hub to rotate; the brake drum is arranged in the brake cavity and connected to the rotor support, and the brake drum is used to cooperate with the brake shoe to brake the wheel hub.

[0007] In this solution, the driving member can drive the rotor support to rotate. Since the rotor support is connected to the wheel hub, it can drive the wheel hub to rotate. By forming a brake cavity on one axial side of the rotor support and arranging the brake drum in the brake cavity, the space occupied by the brake drum can be saved. Since the brake drum is connected to the rotor support, when the wheel hub rotates with the rotor support, the brake drum will also rotate synchronously. The brake drum can be braked by the brake shoe, thereby driving the wheel hub to stop rotating. This structure integrates parts of the brake assembly and the drive assembly, effectively saving the space occupied by the structure near the wheel hub, and facilitating the design of new vehicles. The brake drum is arranged in the brake cavity, which can also reduce the Y-direction dimension of the entire wheel hub motor structure, facilitating layout, and at the same time will not affect the transmission efficiency and braking efficiency.

[0008] In a further solution of the utility model, the brake chamber includes a first chamber and a second chamber arranged in sequence along the axial direction; the brake drum includes a connecting part and a braking part arranged in sequence along the axial direction, the connecting part is arranged in the first chamber and connected to the rotor support, and the braking part is arranged in the second chamber and is used to cooperate with the brake shoe for braking.

[0009] With this design, the brake drum is set in the brake cavity, and the brake function can be effectively realized in cooperation with the support of the brake cavity. Since the brake drum is connected to the rotor support, it can generate braking force through friction with the brake shoe, thereby slowing down or stopping the rotation of the rotor support. The second cavity cooperates with the brake shoe to brake, further enhancing the braking effect.

[0010] In a further embodiment of the utility model, the rotor support includes an inner ring portion, a support portion and an outer ring portion which are arranged in sequence from the inside to the outside in the radial direction; the support portion forms a second cavity and together with the inner ring portion forms a first cavity; the drive member is connected to the outer ring portion, and the inner ring portion forms an installation cavity on the other axial side, and the installation cavity is used to accommodate the wheel hub.

[0011] In this solution, by sequentially arranging the inner ring portion, the support portion and the outer ring portion from the inside to the outside in the radial direction, the rotor support has good structural strength and rigidity to withstand the force and pressure during braking. The inner ring portion and the support portion form a first cavity, so that the brake can more effectively apply the braking torque and transmit the braking action to the rotor support, thereby achieving a more reliable braking effect. The mounting cavity formed on the other axial side of the inner ring portion can conveniently accommodate the wheel hub, making the installation and removal of the wheel hub more convenient.

[0012] In a further solution of the present invention, the inner ring portion, the support portion and the outer ring portion are integrally formed.

[0013] In this solution, the inner ring portion, the supporting portion and the outer ring portion are integrally formed, which can ensure the stability of the entire structure while also providing effective support for the wheel hub and the brake drum.

[0014] In a further embodiment of the utility model, the inner ring portion includes a main body portion, an extension portion and a sealing portion which are arranged in sequence along the axial direction; the main body portion and the support portion together form a first cavity, the extension portion extends along the axial direction and forms an installation cavity together with the main body portion, and the sealing portion extends radially and protrudes from the extension portion.

[0015] In this solution, the main body portion and the support portion together form a first cavity to accommodate the brake drum, and the extension portion extends axially and together with the main body portion forms a mounting cavity for accommodating the wheel hub.

[0016] In a further solution of the utility model, the main body includes a first mounting segment and a second mounting segment which are arranged in sequence from the inside to the outside in the radial direction, and the first mounting segment protrudes from the second mounting segment in the axial direction to form a first cavity together with the second mounting segment and the support portion; the first mounting segment is provided with a through hole for the wheel hub bearing to pass through, and the second mounting segment is connected to the connecting portion.

[0017] In this solution, the first mounting section protrudes axially from the second mounting section to enclose a first cavity together with the second mounting section and the support portion for mounting the connecting section. The first mounting section has a through hole for the wheel hub bearing to pass through, and the transmission shaft also passes through the wheel hub.

[0018] In a further solution of the utility model, the outer ring portion includes a plurality of mounting protrusions arranged at intervals along the circumferential direction; the driving member includes a plurality of coils, and the plurality of coils are respectively arranged on a corresponding mounting protrusion.

[0019] In this solution, a plurality of mounting protrusions are spaced apart in the circumferential direction of the outer ring portion, and the coils are respectively sleeved on the corresponding mounting protrusions. When the coils are energized, the rotor support can be driven to rotate.

[0020] In a further solution of the utility model, the hub motor structure also includes multiple connecting parts, the second mounting section is provided with multiple first connecting holes, and the multiple first connecting holes are arranged at intervals along the circumferential direction; the connecting part is provided with multiple second connecting holes, and the multiple second connecting holes are arranged one by one corresponding to the multiple first connecting holes; the connecting parts pass through the corresponding first connecting holes and the corresponding second connecting holes to connect the rotor support and the brake drum.

[0021] In this scheme, when the connecting member passes through the first connecting hole and the second connecting hole, the brake drum and the rotor support can be axially fixed. The multiple first connecting holes and the multiple second connecting holes are correspondingly arranged at intervals in the circumferential direction, which can improve the radial connection strength between the brake drum and the rotor support.

[0022] In a further solution of the utility model, the first mounting section is further provided with a plurality of third connecting holes, which are arranged at intervals along the circumferential direction and are used for connecting to the wheel hub.

[0023] In this solution, the wheel hub can be connected by opening a plurality of third connection holes spaced apart in the circumferential direction of the first mounting section.

[0024] A second aspect of the utility model provides a vehicle, comprising the hub motor structure provided by the first aspect of the utility model.

[0025] In summary, the wheel hub motor structure and vehicle provided by the present application have at least the following beneficial effects:

[0026] The driving member can drive the rotor support to rotate. Since the rotor support is connected to the wheel hub, it can drive the wheel hub to rotate. By forming a brake cavity on one axial side of the rotor support and arranging the brake drum in the brake cavity, the space occupied by the brake drum can be saved. Since the brake drum is connected to the rotor support, when the wheel hub rotates with the rotor support, the brake drum will also rotate synchronously. The brake drum can be braked by the brake shoe, thereby driving the wheel hub to stop rotating. This structure integrates parts of the brake assembly and the drive assembly, effectively saving the space occupied by the structure near the wheel hub, and facilitating the design of new vehicles. Arranging the brake drum in the brake cavity can also reduce the Y-direction dimension of the entire wheel hub motor structure, facilitating layout, and at the same time will not affect the transmission efficiency and braking efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific implementation or the prior art description. Obviously, the drawings described below are some implementations of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 A schematic diagram of the three-dimensional structure of the wheel hub motor structure provided in an embodiment of the present application;

[0029] Figure 2 A cross-sectional view of the hub motor structure provided in an embodiment of the present application;

[0030] Figure 3 A schematic diagram of the structure of a brake drum provided in an embodiment of the present application; and

[0031] Figure 4 A schematic structural diagram of a rotor support provided in an embodiment of the present application.

[0032] The reference numerals are as follows:

[0033] 100, rotor support; 100A, brake cavity; 100B, first cavity; 100C, second cavity; 100D, mounting cavity; 110, outer ring portion; 111, mounting protrusion; 120, support portion; 130, inner ring portion; 131, main body portion; 1311, second mounting section; 1311A, first connecting hole; 1312, first mounting section; 1312A, third connecting hole; 1321B, through hole; 132, extension portion; 133, sealing portion;

[0034] 200, driving member; 210, coil;

[0035] 300, brake drum; 310, brake portion; 320, connection portion; 320A, second connection hole;

[0036] 400. Connectors. DETAILED DESCRIPTION

[0037] In the description of the present application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like appear to indicate the orientation or position relationship, unless otherwise specified, they are understood to be based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and do not indicate or imply 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 application.

[0038] In addition, if there is a feature defined as "first" or "second", it is only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Features defined as "first" or "second" may explicitly or implicitly include at least one of the defined features. If there is a description of "plurality", the general meaning is to include at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0039] In this application, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed" and so on should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection, it can be a direct connection, or it can be an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0040] In the description of this specification, if the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" appear, it means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0041] Please refer to Figure 1 and Figure 2In a first aspect, the utility model provides a hub motor structure, including a rotor support 100, a brake drum 300 and a driving member 200; the rotor support 100 is used to connect the wheel hub, and the rotor support 100 is formed with a brake cavity 100A on one axial side; the driving member 200 is connected to the rotor support 100, and is used to drive the rotor support 100 to drive the wheel hub to rotate; the brake drum 300 is arranged in the brake cavity 100A and connected to the rotor support 100, and the brake drum 300 is used to cooperate with the brake shoe to brake the wheel hub.

[0042] In this solution, the driving member 200 can drive the rotor support 100 to rotate. Since the rotor support 100 is connected to the wheel hub, the wheel hub can be driven to rotate. By forming a brake chamber 100A on one axial side of the rotor support 100 and arranging the brake drum 300 in the brake chamber 100A, the space occupied by the brake drum 300 can be saved. Since the brake drum 300 is connected to the rotor support 100, when the wheel hub rotates with the rotor support 100, the brake drum 300 will also rotate synchronously. The brake drum 300 can be braked by the brake shoe, thereby driving the wheel hub to stop rotating. This structure integrates parts of the brake assembly and the drive assembly, effectively saving the space occupied by the structure near the wheel hub, and facilitating the design of new vehicles. The brake drum 300 is arranged in the brake chamber 100A, which can also reduce the Y-direction dimension of the entire wheel hub motor structure, facilitating layout, and at the same time will not affect the transmission efficiency and braking efficiency.

[0043] It should be noted that the conventional rotor structure includes a rotor support 100 and a driving member 200 .

[0044] Please refer to Figure 3 In a further embodiment, the brake chamber 100A includes a first chamber 100B and a second chamber 100C arranged in sequence along the axial direction; the brake drum 300 includes a connecting portion 320 and a braking portion 310 arranged in sequence along the axial direction, the connecting portion 320 is arranged in the first chamber 100B and connected to the rotor support 100, and the braking portion 310 is arranged in the second chamber 100C and is used to cooperate with the brake shoe for braking.

[0045] Through this design, the brake drum 300 is disposed in the brake chamber 100A, and the brake function can be effectively realized by cooperating with the support of the brake chamber 100A. Since the brake drum 300 is connected to the rotor support 100, it can generate a braking force by friction with the brake shoe, thereby slowing down or stopping the rotation of the rotor support 100. The second chamber 100C cooperates with the brake shoe to brake, further enhancing the braking effect.

[0046] In a specific application, the braking portion 310 is an axially extending annular structure, and the brake shoe is arranged in a cavity surrounded by the brake drum 300. When braking is required, the brake shoe is brought into contact with the inner wall of the braking portion 310 to generate friction, thereby braking the rotor support 100 and the wheel hub. The connecting portion 320 is a sheet structure, and an opening (not marked in the figure) is provided on the connecting portion 320 for the transmission shaft to pass through and the wheel hub bearing to be installed, which also facilitates the insertion of the brake drum 300 into the first cavity 100B.

[0047] In a further embodiment, the rotor support 100 includes an inner ring portion 130, a support portion and an outer ring portion 110 which are arranged in sequence from the inside to the outside in the radial direction; the support portion forms a second cavity 100C and together with the inner ring portion 130 forms a first cavity 100B; the driving member 200 is connected to the outer ring portion 110, and the inner ring portion 130 forms an installation cavity 100D on the other axial side, and the installation cavity 100D is used to install the wheel hub.

[0048] In this solution, by sequentially arranging the inner ring portion 130, the support portion 120 and the outer ring portion 110 from the inside to the outside in the radial direction, the rotor support 100 has good structural strength and rigidity to withstand the force and pressure during braking. The inner ring portion 130 and the support portion 120 form a first cavity 100B, so that the brake can more effectively apply the braking torque and transmit the braking effect to the rotor support 100, thereby achieving a more reliable braking effect. The installation cavity 100D formed on the other axial side of the inner ring portion 130 can conveniently accommodate the wheel hub, making the installation and removal of the wheel hub more convenient.

[0049] In a further embodiment, the inner ring portion 130 , the support portion 120 and the outer ring portion 110 are integrally formed.

[0050] In this solution, the inner ring portion 130 , the support portion 120 and the outer ring portion 110 are integrally formed, which can ensure the stability of the entire structure and also provide effective support for the wheel hub and the brake drum 300 .

[0051] In a further embodiment, the inner ring portion 130 includes a main body portion 131, an extension portion 132 and a sealing portion 133 which are arranged in sequence along the axial direction; the main body portion 131 and the support portion 120 together form a first cavity 100B, the extension portion 132 extends along the axial direction and forms an installation cavity 100D together with the main body portion 131, and the sealing portion 133 extends radially and protrudes from the extension portion 132.

[0052] In this solution, the main body portion 131 and the support portion 120 together form a first cavity 100B to accommodate the brake drum 300 , and the extension portion 132 extends axially and together with the main body portion 131 forms a mounting cavity 100D for accommodating the wheel hub.

[0053] In a further embodiment, the main body portion 131 includes a first mounting segment 1312 and a second mounting segment 1311 which are arranged in sequence from the inside to the outside in the radial direction. The first mounting segment 1312 protrudes from the second mounting segment 1311 in the axial direction to form a first cavity 100B together with the second mounting segment 1311 and the support portion 120; the first mounting segment 1312 is provided with a through hole 1321B, and the through hole 1321B is used for the wheel hub bearing to pass through, and the second mounting segment 1311 is connected to the connecting portion 320.

[0054] In this solution, the first mounting section 1312 protrudes axially from the second mounting section 1311 to form a first cavity 100B together with the second mounting section 1311 and the support portion 120 for mounting the connecting section. The first mounting section 1312 has a through hole 1321B for the wheel hub bearing to pass through, and the transmission shaft also passes through the wheel hub at the same time.

[0055] In a further embodiment, the outer ring portion 110 includes a plurality of mounting protrusions 111 spaced apart along the circumferential direction; the driving member 200 includes a plurality of coils 210 , and the plurality of coils 210 are respectively disposed on a corresponding one of the mounting protrusions 111 .

[0056] In this solution, a plurality of mounting protrusions 111 are spaced apart in the circumferential direction of the outer ring portion 110 , and the coils 210 are respectively sleeved on the corresponding mounting protrusions 111 . When the coils 210 are energized, the rotor support 100 can be driven to rotate.

[0057] In a further embodiment, an insulating layer is sprayed on the surface of the mounting protrusion 111 to prevent the rotor support 100 from being electrically connected to the coil 210 .

[0058] Please refer to Figure 4 In a further embodiment, the hub motor structure also includes a plurality of connectors 400, the second mounting section 1311 is provided with a plurality of first connector holes 1311A, and the plurality of first connector holes 1311A are arranged at intervals along the circumferential direction; the connecting portion 320 is provided with a plurality of second connector holes 320A, and the plurality of second connector holes 320A are arranged one-to-one corresponding to the plurality of first connector holes 1311A; the connectors 400 pass through the corresponding first connector holes 1311A and the corresponding second connector holes 320A to connect the rotor support 100 and the brake drum 300.

[0059] In this solution, when the connecting member 400 passes through the first connecting hole 1311A and the second connecting hole 320A, the brake drum 300 and the rotor support 100 can be axially fixed. The multiple first connecting holes 1311A and the multiple second connecting holes 320A are correspondingly arranged at intervals in the circumferential direction, which can improve the radial connection strength between the brake drum 300 and the rotor support 100. The connecting member 400 is generally a hexagonal bolt and a nut and a gasket that match it.

[0060] In a further embodiment, the first mounting section 1312 is further provided with a plurality of third connection holes 1312A, and the plurality of third connection holes 1312A are arranged at intervals along the circumferential direction for connecting to the wheel hub.

[0061] In this solution, the wheel hub can be connected by opening a plurality of third connection holes 1312A spaced apart in the circumferential direction of the first mounting section 1312 .

[0062] When installing the wheel hub, the brake drum 300 should be installed into the brake cavity 100A first, and then the wheel hub bearing should be installed into the cavity formed by the brake drum 300, and finally the wheel hub and the wheel hub bearing are connected through the connecting structure through the connecting hole.

[0063] In a specific application, the rotor support 100 is generally made of 45 steel, and the brake drum 300 is made of HT250 material.

[0064] A second aspect of the utility model provides a vehicle, comprising the hub motor structure provided by the first aspect of the utility model.

[0065] In this solution, by adopting the hub motor structure provided in the present application, the Y-axis space occupied by the hub and the drive shaft can be reduced, thereby facilitating the setting of structures such as the suspension and brakes. At the same time, the weight is also reduced relative to the original structure, facilitating the design of a lightweight vehicle body.

[0066] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Those skilled in the art can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A hub motor structure, characterized in that: It comprises a rotor support (100), a brake drum (300) and a driving member (200); The rotor support (100) is used to connect to the wheel hub, and a brake chamber (100A) is formed on one axial side of the rotor support (100); The driving member (200) is connected to the rotor support (100) and is used to drive the rotor support (100) to drive the wheel hub to rotate; The brake drum (300) is arranged in the brake chamber (100A) and connected to the rotor support (100); the brake drum (300) is used to cooperate with a brake shoe to brake the wheel hub.

2. The wheel hub motor structure according to claim 1, characterized in that: The brake chamber (100A) comprises a first chamber (100B) and a second chamber (100C) which are sequentially arranged along the axial direction; The brake drum (300) comprises a connecting portion (320) and a braking portion (310) which are sequentially arranged along the axial direction, wherein the connecting portion (320) is arranged in the first cavity (100B) and connected to the rotor support (100), and the braking portion (310) is arranged in the second cavity (100C) and is used to cooperate with the brake shoe for braking.

3. The wheel hub motor structure according to claim 2, characterized in that: The rotor support (100) comprises an inner ring portion (130), a support portion (120) and an outer ring portion (110) which are arranged sequentially from the inside to the outside in the radial direction; The support portion (120) is formed with the second cavity (100C) and together with the inner ring portion (130) forms the first cavity (100B); The driving member (200) is connected to the outer ring portion (110), and the inner ring portion (130) is formed with a mounting cavity (100D) on the other axial side, and the mounting cavity (100D) is used to accommodate the wheel hub.

4. The wheel hub motor structure according to claim 3, characterized in that: The inner ring portion (130), the support portion (120) and the outer ring portion (110) are integrally formed.

5. The wheel hub motor structure according to claim 3, characterized in that: The inner ring portion (130) comprises a main body portion (131), an extension portion (132) and a sealing portion (133) which are sequentially arranged along the axial direction; The main body portion (131) and the support portion (120) together form the first cavity (100B), the extension portion (132) extends along the axial direction and together with the main body portion (131) forms the installation cavity (100D), and the sealing portion (133) extends along the radial direction and protrudes from the extension portion (132).

6. The wheel hub motor structure according to claim 5, characterized in that: The body portion (131) comprises a first mounting segment (1312) and a second mounting segment (1311) which are sequentially arranged from the inside to the outside in the radial direction, and the first mounting segment (1312) protrudes from the second mounting segment (1311) in the axial direction to enclose the first cavity (100B) together with the second mounting segment (1311) and the support portion (120); The first mounting section (1312) is provided with a through hole (1321B), and the through hole (1321B) is used for allowing the wheel hub bearing to pass through, and the second mounting section (1311) is connected to the connecting portion (320).

7. The wheel hub motor structure according to claim 3, characterized in that: The outer ring portion (110) comprises a plurality of mounting protrusions (111) arranged at intervals along the circumferential direction; The driving member (200) comprises a plurality of coils (210), and the plurality of coils (210) are respectively arranged on a corresponding one of the mounting protrusions (111).

8. The wheel hub motor structure according to claim 6, characterized in that: The wheel hub motor structure further comprises a plurality of connecting members (400), the second mounting section (1311) is provided with a plurality of first connecting holes (1311A), and the plurality of first connecting holes (1311A) are arranged at intervals along the circumferential direction; The connecting portion (320) is provided with a plurality of second connecting holes (320A), and the plurality of second connecting holes (320A) are arranged in a one-to-one correspondence with the plurality of first connecting holes (1311A); The connecting member (400) passes through the corresponding first connecting hole (1311A) and the corresponding second connecting hole (320A) to connect the rotor support (100) and the brake drum (300).

9. The wheel hub motor structure according to claim 6, characterized in that: The first mounting section (1312) is also provided with a plurality of third connection holes (1312A), and the plurality of third connection holes (1312A) are arranged at intervals along the circumferential direction for connecting to the wheel hub.

10. A vehicle, characterized in that: The invention comprises the hub motor structure as described in any one of claims 1 to 9.

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