Hub motor, wheel-foot robot and vehicle

Abstract

The invention belongs to the technical field of motors and robots, and particularly relates to a high-integration hub motor, a wheel-foot robot and a vehicle. A first motor (1) of the hub motor is a driving motor, a second motor (3) is a steering motor, and the driving motor and the steering motor are arranged in a nested mode. When the first motor (1) works, the outer rotor (11) drives the hub ring (2) to rotate, so that the vehicle advances or retreats; when the second motor (3) works, an inner rotor (32) of the second motor (3) rotates and drives the whole hub motor assembly to deflect around a specific axis by being connected with an external steering mechanism, so that steering is achieved. According to the structure that the motor sleeves the motor, the axial size and the radial size are greatly compressed, integration of driving and steering is achieved, and the steering device is particularly suitable for wheel-foot robots or special vehicles with strict space requirements.

Description

Technical Field

[0001] This invention belongs to the field of motor and robot technology, and particularly relates to a highly integrated hub motor, wheeled robot and vehicle. Background Technology

[0002] With the rapid development of mobile robot technology, automated guided vehicles (AGVs), and new energy vehicle technology, increasingly higher requirements are being placed on the flexibility and integration of drive units. Especially in wheeled robots or omnidirectional mobile platforms, wheel modules typically need to have at least two degrees of freedom: one is the "walking degree of freedom" of rotation around the wheel axle, and the other is the "steering degree of freedom" of rotation around the vertical axis (or joint axis).

[0003] In existing technologies, a split-type structural design is typically used to achieve the aforementioned two degrees of freedom. That is, a standard hub motor is used as the power source for movement and is installed inside the wheel; while to achieve steering or connection to the leg joint, an additional independent motor and reduction mechanism (i.e., steering drive assembly) needs to be installed outside the hub motor (e.g., above or to the side). This drive assembly is usually physically connected to the hub motor through a complex robotic arm, connecting fork, or bracket.

[0004] Because the steering motor and the walking motor are physically separate and arranged in series or parallel, the overall wheel-leg end-effector module has a large axial or radial dimension, making it difficult to meet the extreme pursuit of lightweight and miniaturization in modern robots. Therefore, how to reduce the size of the wheel-leg end-effector module, improve power density and integration while ensuring that the hub motor has the dual functions of walking and steering (or driving external mechanisms) is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] In view of this, the present invention proposes a hub motor, a wheeled robot, and a vehicle, aiming to solve the problem of loose structure and large space occupation caused by the separation of the drive module and steering module of the walking mechanism in the prior art.

[0006] In a first aspect, in a hub motor provided by the present invention, the hub motor includes a first motor and a second motor. The first motor includes an outer rotor and an inner stator arranged coaxially. A hub ring is connected to the radially outer side of the outer rotor, and a receiving cavity is formed on the inner side of the inner stator. The second motor includes an outer stator and an inner rotor arranged coaxially. The outer stator is connected in the receiving cavity, and the inner rotor is configured to drive a steering mechanism outside the power assembly.

[0007] In a preferred embodiment of the hub motor provided by the present invention, an annular partition is formed on the inner side of the inner stator, which divides the receiving cavity of the inner stator into a motor cavity and a reduction gear cavity; the second motor is disposed in the motor cavity, and the output end of the inner rotor is also connected to a reducer, the housing of the reducer is connected to the inner stator, and at least a portion of the reducer is disposed in the reduction gear cavity.

[0008] In a preferred embodiment of the hub motor provided by the present invention, the hub motor further includes a first end bracket, a mounting base, and a first encoder assembly. The first end bracket is peripherally connected to the hub ring, and the mounting base is connected to the housing of the reducer. The first encoder assembly includes a code disk and a reader head disposed opposite to each other; the code disk is connected to the first end bracket, and the reader head is connected to the mounting base.

[0009] In a preferred embodiment of the hub motor provided by the present invention, the circumferential inner diameter of the encoder disk corresponds to the circumferential inner diameter of the first end bracket; and the mounting base is configured such that the connection between the mounting base and the housing of the reducer is located on the axial inner side of the first end bracket, and the reading head is located on the axial outer side of the first end bracket.

[0010] In a preferred embodiment of the hub motor provided by the present invention, a first support ring portion is formed on the radially outer side of the inner stator, and a first bearing is provided between the outer ring wall of the first support ring portion and the inner ring wall of the hub ring; or, a second bearing is connected between the inner ring wall of the first shaft hole of the partition portion and the outer ring wall of the inner rotor.

[0011] In a preferred embodiment of the hub motor provided by the present invention, a plurality of extension portions are provided between the first support ring portion and the body of the inner stator. The plurality of extension portions are arranged in a ring array along the body of the inner stator, and a hollow portion is formed between each pair of adjacent extension portions.

[0012] In a preferred embodiment of the hub motor provided by the present invention, the curvature of the inner stator corresponding to the hollow portion is greater than the curvature of the inner stator corresponding to the extension portion; or, it further includes an annular first protective net, which is connected to the extension portion and covers multiple hollow portions.

[0013] In a preferred embodiment of the hub motor provided by the present invention, the hub motor further includes a second end bracket, which is disposed on the side of the hub ring away from the steering mechanism. A second support ring portion is formed on the radially outer side of the second end bracket and a second shaft hole is formed on the radially inner side. A third bearing is disposed between the second support ring portion and the hub ring, and a fourth bearing is disposed between the second shaft hole and the inner rotor.

[0014] In a preferred embodiment of the hub motor provided by the present invention, the hub motor further includes an end cover, a feedback shaft, and a second encoder assembly. The end cover is connected to the axial outer side of the second end bracket and forms an electrical cavity between it and the second end bracket; one end of the feedback shaft is connected to the output end of the reducer, and the other end passes through the reducer and the inner rotor and extends into the electrical cavity; wherein, the reducer is connected to the output end of the inner rotor; the second encoder assembly is disposed in the electrical cavity and is used to detect the rotation values ​​of the inner rotor and the feedback shaft.

[0015] In a second aspect, the present invention also provides a wheeled robot equipped with a hub motor as described in any of the embodiments of the first aspect above.

[0016] Thirdly, the present invention also provides a vehicle equipped with a hub motor as described in any of the embodiments of the first aspect above.

[0017] The technical advantages of the hub motor, wheeled robot, and vehicle of this invention are as follows: When the first motor of the hub motor is working, its outer rotor drives the hub ring to rotate, realizing the forward or backward movement of the vehicle; when the second motor is working, its inner rotor rotates, and through connection to an external steering mechanism, drives the entire hub motor assembly to deflect around a specific axis, thereby achieving steering. This "motor-within-a-motor" structure greatly compresses the axial and radial dimensions, realizing the integration of drive and steering, and is particularly suitable for wheeled robots or special vehicles with demanding space requirements. Attached Figure Description

[0018] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which will make the above and other features and advantages of the present invention more apparent to those skilled in the art. In the drawings:

[0019] Figure 1 This is a schematic diagram of the external structure of the hub motor in this embodiment from a first-view perspective.

[0020] Figure 2 This is a cross-sectional structural diagram of the hub motor in this embodiment.

[0021] Figure 3 This is an exploded structural diagram of the hub motor in this embodiment.

[0022] Figure 4 This is a first-view structural schematic diagram of the inner stator in the hub motor of this embodiment.

[0023] Figure 5 This is a structural schematic diagram of the inner stator in the hub motor of this embodiment from a second perspective.

[0024] Figure 6 This is a schematic diagram of the external structure of the hub motor in this embodiment from a second perspective.

[0025] Figure 7 This is a schematic diagram showing the installation position of the second encoder assembly of the hub motor in this embodiment.

[0026] The reference numerals in the attached figures are as follows:

[0027] 1-First motor; 11-Outer rotor;

[0028] 12-Inner stator; 1201-Motor cavity; 1202-Reduction chamber;

[0029] 121 - Partition section; 122 - First support ring section; 123 - Extension section; 124 - Hollowed-out section; 125 - First protective net;

[0030] 2-Rim ring; 21-Tire;

[0031] 3-Second motor; 31-Outer stator; 32-Inner rotor;

[0032] 4-Reducer;

[0033] 5-First end bracket; 51-Mounting base;

[0034] 61-First encoder assembly; 611-Code disk; 612-Reader head;

[0035] 62 - Second encoder assembly;

[0036] 7-Second end bracket; 71-Second support ring; 72-Second protective net;

[0037] 81-First bearing; 82-Second bearing; 83-Third bearing; 84-Fourth bearing;

[0038] 91-End cap; 92-Feedback shaft. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0040] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "connection" and "configuration" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] Furthermore, it should be understood in the description of this application that the terms “center,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0042] This embodiment provides a wheeled robot, whose leg end is equipped with a hub motor as described in any of the embodiments below. For example, the inner rotor 32 of the hub motor drives the robot's leg linkage, enabling the robot to perform complex movements such as 360-degree turning in place, diagonal movement, and lateral movement, and the leg end inertia is small, allowing for flexible movement.

[0043] In the vehicle provided in this embodiment, the vehicle can be a new energy vehicle or an AGV logistics vehicle, etc., and the vehicle is equipped with a hub motor as described in any of the embodiments below. For example, all four wheels use the hub motor and are connected through the suspension system. This enables four-wheel independent drive and four-wheel independent steering (4WD4WS), greatly reducing the turning radius, and even enabling "U"-shaped parking or U-turns, improving the vehicle's handling and passability.

[0044] This embodiment provides a highly integrated hub motor, such as Figure 1 and Figure 2 As shown, this design aims to solve the problem of loose structure and large space occupation caused by the separation of drive module and steering module in the existing technology.

[0045] Combination Figure 2 and Figure 3The hub motor is mainly composed of two core power sources: a first motor 1 and a second motor 3. The first motor 1 is a drive motor, and the second motor 3 is a steering motor. The two are nested in a nested layout.

[0046] The first motor 1, serving as the driving source for a vehicle or robot, employs an outer rotor 11 structure. It includes a coaxially arranged outer rotor 11 and an inner stator 12. The inner stator is equipped with an inner stator support and windings. The outer rotor 11 of the first motor 1 is located radially outward, with a hub ring 2 (or directly integrated into a hub) connected to its outer circumference for mounting a tire 21 or directly contacting the ground as a walking wheel. The inner stator 12 of the first motor 1 is located radially inward and is fixed relative to the frame or suspension system. Notably, this inner stator 12 is not only part of the magnetic circuit but also the skeleton of the entire hub motor. The center of the inner stator 12 is not a solid structure; a large receiving cavity is formed on its inner side.

[0047] The second motor 3 is designed to enable in-situ or in-motion steering of the wheels, and it is cleverly arranged within the internal space of the first motor 1. The outer stator 31 of the second motor 3 is directly connected to or interference-fitted into the housing cavity of the inner stator 12 of the first motor 1. This means that the inner stator 12 of the first motor 1 serves as the housing of the second motor 3, achieving structural reuse. The inner rotor 32 of the second motor 3 is configured as the power output end, used to drive the steering mechanism outside the power assembly.

[0048] It should be noted that the inner rotor 32 in this embodiment can be formed by detachably connecting the body of the inner rotor 32 and the motor shaft, or it can be integrally formed.

[0049] The working principle and technical effects of the hub motor in this embodiment are as follows: When the first motor 1 is working, the outer rotor 11 drives the hub ring 2 to rotate, realizing the forward or backward movement of the vehicle; when the second motor 3 is working, its inner rotor 32 rotates, and through connection with an external steering mechanism (such as gears, racks, connecting rods, etc.), drives the entire hub motor assembly to deflect around a specific axis, thereby achieving steering. This "motor-within-a-motor" structure greatly compresses the axial and radial dimensions, realizing the integration of drive and steering, and is particularly suitable for wheeled robots or special vehicles with demanding space requirements.

[0050] To improve steering torque, the second motor 3 can also be used in conjunction with the reducer 4. Figures 2 to 5This embodiment further optimizes the internal structure of the inner stator 12. An annular partition 121 is formed inside the inner stator 12 of the first motor 1. This partition 121 physically divides the receiving cavity of the inner stator 12 into two independent chambers in the axial direction: a motor cavity 1201 and a reduction gear cavity 1202. The main body (stator and rotor) of the second motor 3 is disposed in the motor cavity 1201. At least a portion of the structure of the reducer 4 (e.g., a planetary gear reducer or a harmonic reducer) is disposed in the reduction gear cavity 1202.

[0051] The output end of the inner rotor 32 of the second motor 3 is connected to the input end of the reducer 4. The outer housing of the reducer 4 is fixedly connected to the inner stator 12, specifically to the annular partition 121 or the inner wall of the inner stator 12. The output end of the reducer 4 extends out of the inner stator 12 to output high torque.

[0052] In this embodiment, the annular partition 121 not only serves as a physical separator and provides dust and oil protection, but also enhances the structural rigidity of the inner stator 12. By embedding the reducer 4 into the reduction chamber 1202 of the inner stator 12, the dead space inside the stator of the first motor 1 is fully utilized, making the overall structure of the hub motor more compact.

[0053] Continue to refer to Figure 1 To achieve precise control of the wheel hub speed, this embodiment also includes a detection component on one side of the hub motor. Therefore, the hub motor also includes a first end bracket 5, a mounting base 51, and a first encoder assembly 61. The first end bracket 5 is disc-shaped or ring-shaped, and its periphery is securely connected to the hub ring 2, rotating synchronously with the hub ring 2. The mounting base 51 is fixedly connected to the housing of the reducer 4 and is stationary relative to the stator. The first encoder assembly 61 is used to detect the wheel speed. It includes an encoder disk 611 and a reader head 612 arranged opposite each other.

[0054] In the first encoder assembly 61, its code disk 611 is connected to the first end bracket 5. Preferably, the circumferential inner diameter of the code disk 611 corresponds to the circumferential inner diameter of the first end bracket 5, and the two are coaxially fitted. The read head 612 is connected to the mounting base 51. To save axial space, the mounting base 51 is configured in a U-shape or stepped shape, so that its connection with the housing of the reducer 4 is located on the axial inner side of the first end bracket 5, while the read head 612 is connected on the axial outer side of the first end bracket 5. This layout facilitates the wiring and installation of the first encoder assembly 61 and enables high-precision closed-loop control of the drive motor.

[0055] Combination Figure 2A first support ring portion 122 is formed radially outside the inner stator 12 of the first motor 1. A first bearing 81 (e.g., a large-diameter thin-walled ball bearing or a crossed roller bearing) is disposed between the outer ring wall of the first support ring portion 122 and the inner ring wall of the hub ring 2. The first bearing 81 bears the main weight of the vehicle and road impacts.

[0056] Combination Figure 2 A first shaft hole is provided at the center of the annular partition 121. A second bearing 82 is connected between the inner ring wall of the shaft hole and the outer ring wall of the inner rotor 32 of the second motor 3 to ensure the rotation accuracy of the steering motor rotor.

[0057] Combination Figure 2 A second end bracket 7 is provided on the side of the hub ring 2 away from the steering mechanism (i.e., the outer side of the vehicle or the non-output side). A second support ring portion 71 is formed radially outward of the second end bracket 7, and a second shaft hole is formed radially inward. A third bearing 83 is disposed between the second support ring portion 71 and the hub ring 2, forming a rotational support system for the hub together with the aforementioned first bearing 81. A fourth bearing 84 is disposed between the second shaft hole and the inner rotor 32, and is used to support the rotor tail of the second motor 3.

[0058] To reduce weight and improve heat dissipation, the first support ring 122 is not solidly connected to the body of the inner stator 12, but rather has multiple extensions 123 (spoke structure). These extensions 123 are arranged in a ring array along the body of the inner stator 12. A perforated portion 124 is formed between each pair of adjacent extensions 123, serving as a ventilation hole. The curvature of the inner stator 12 corresponding to the perforated portion 124 is greater than that corresponding to the extensions 123, i.e., "larger holes, smaller ribs," maximizing ventilation area and reducing weight while ensuring strength. This spoke-type stator support design effectively blocks the conduction of heat from the stator to the bearings, while simultaneously utilizing the airflow generated by the wheel rotation to force-cool the motor interior through the perforated portion 124.

[0059] Continue to refer to Figure 1 Furthermore, to prevent foreign objects from entering the perforated portions 124 and damaging the motor windings, a first annular protective mesh 125 is also included. This first protective mesh 125 is connected to the extension 123 and covers the multiple perforated portions 124. The first protective mesh 125 can be a stamped metal mesh or a high-strength nylon mesh.

[0060] Similarly, combining Figure 6 and Figure 7Multiple extensions (spoke structure) are also provided between the body of the second end bracket 7 and the second support ring 71. These extensions are arranged in a ring array along the inner stator 12 body. A perforated section is formed between each pair of adjacent extensions, which also functions as a ventilation hole. This spoke-type stator bracket design effectively blocks the conduction of stator heat to the bearings, while utilizing the airflow generated by the wheel rotation to force-cool the motor interior through the perforated section. Correspondingly, to prevent foreign objects from entering the perforated section and damaging the motor windings, a ring-shaped second protective net 72 is also included. This second protective net 72 is connected to the extensions of the second end bracket 7 and covers the multiple perforated sections. The second protective net 72 can be a metal stamped mesh or a high-strength nylon mesh.

[0061] Combination Figure 2 , Figure 6 and Figure 7 In order to detect the steering angle, i.e. the output state of the second motor 3, the hub motor is also equipped with an end cover 91, a feedback shaft 92, and a second encoder assembly 62.

[0062] The end cap 91 is connected to the axial outer side of the second end bracket 7, forming an electrical cavity between the end cap 91 and the second end bracket 7, and the electrical interface is provided on the end cap 91.

[0063] The feedback shaft 92 is a slender shaft. One end of the feedback shaft 92 is connected to the output end of the reducer 4, and the other end passes through the central through hole of the reducer 4 and the inner rotor 32 and extends into the electrical cavity.

[0064] The second encoder assembly 62 is disposed in the electrical cavity. The second encoder assembly 62 can be a dual encoder assembly, used to sense the rotation of the inner rotor 32 of the second motor 3 and the feedback shaft 92 connected to the reducer 4.

[0065] When the second motor 3 drives the reducer 4 to steer, the actual rotation angles at the outputs of both the second motor 3 and the reducer 4 are transmitted to the second encoder assembly 62 within the electrical cavity via the feedback shaft 92. This design places the precision steering encoder in the outermost electrical cavity of the motor, away from the oil contaminants in the gearbox and the high-temperature area of ​​the motor, facilitating maintenance and replacement. Simultaneously, it allows direct acquisition of the actual rotation angles at the input and output ends of the reducer 4, eliminating measurement errors caused by the backlash of the reducer 4 teeth.

[0066] The hub motor described in this specific embodiment achieves a highly integrated, high-power-density, and precisely controlled power unit through a unique inner and outer motor nesting structure, a reasonable heat dissipation duct design, and a precise dual encoder feedback system.

[0067] It should be understood that although this specification is described according to various embodiments, not every embodiment or implementation method contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0068] The above descriptions are merely illustrative embodiments of this application and are not intended to limit the scope of the embodiments of this application. Any equivalent changes, modifications, and combinations made by those skilled in the art without departing from the concept and principles of the embodiments of this application should fall within the protection scope of the embodiments of this application.

Claims

1. A hub motor, characterized in that, include: The first motor (1) includes an outer rotor (11) and an inner stator (12) arranged coaxially. A hub ring (2) is connected to the radially outer side of the outer rotor (11), and a receiving cavity is formed on the inner side of the inner stator (12). The second motor (3) includes an outer stator (31) and an inner rotor (32) arranged coaxially, the outer stator (31) being connected in the receiving cavity, and the inner rotor (32) being configured to drive a steering mechanism outside the power assembly.

2. The hub motor according to claim 1, characterized in that, An annular partition (121) is formed on the inner side of the inner stator (12), and the partition (121) divides the receiving cavity of the inner stator (12) into a motor cavity (1201) and a deceleration cavity (1202). The second motor (3) is disposed in the motor cavity (1201), and the output end of the inner rotor (32) is also connected to a reducer (4). The outer shell of the reducer (4) is connected to the inner stator (12), and at least a portion of the reducer (4) is disposed in the reducer cavity (1202).

3. The hub motor according to claim 2, characterized in that, Also includes: The first end bracket (5) is connected to the hub ring (2) around its periphery; Mounting base (51) is attached to the housing of the reducer (4); A first encoder assembly (61) includes a code disk (611) and a reader (612) disposed opposite to each other, the code disk (611) being connected to a first end bracket (5) and the reader (612) being connected to a mounting base (51).

4. The hub motor according to claim 3, characterized in that, The circumferential inner diameter of the code disk (611) corresponds to the circumferential inner diameter of the first end bracket (5); and, The mounting base (51) is configured such that the connection between it and the housing of the reducer (4) is located on the axial inner side of the first end bracket (5), and the reading head (612) is located on the axial outer side of the first end bracket (5).

5. The hub motor according to claim 2, characterized in that, The inner stator (12) has a first support ring portion (122) formed radially outside, and a first bearing (81) is provided between the outer ring wall of the first support ring portion (122) and the inner ring wall of the hub ring (2); or, A second bearing (82) is connected between the inner ring wall of the first shaft hole of the partition (121) and the outer ring wall of the inner rotor (32).

6. The hub motor according to claim 5, characterized in that, A plurality of extensions (123) are provided between the first support ring (122) and the body of the inner stator (12). The plurality of extensions (123) are arranged in a ring array along the body of the inner stator (12), and a hollow portion (124) is formed between each two adjacent extensions (123).

7. The hub motor according to claim 6, characterized in that, The curvature of the inner stator (12) corresponding to the hollow portion (124) is greater than the curvature of the inner stator (12) corresponding to the extension portion (123); or, It also includes a ring-shaped first protective net (125), which is connected to the extension (123) and covers the plurality of the cutouts (124).

8. The hub motor according to claim 1, characterized in that, Also includes: The second end bracket (7) is disposed on the side of the hub ring (2) away from the steering mechanism. The second end bracket (7) has a second support ring portion (71) formed on its radially outer side and a second shaft hole formed on its radially inner side. A third bearing (83) is disposed between the second support ring portion (71) and the hub ring (2), and a fourth bearing (84) is disposed between the second shaft hole and the inner rotor (32).

9. A wheeled robot, characterized in that, It is equipped with a hub motor as described in any one of claims 1 to 8.

10. A vehicle, characterized in that, It is equipped with a hub motor as described in any one of claims 1 to 8.

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