A direct drive middle motor

Abstract

The application discloses a direct-drive middle-mounted motor in the technical field of motors, which comprises a motor body, a hollow output shaft, a rigid main shaft and an electromagnetic absorption assembly. The hollow output shaft is arranged on the motor body in a rotating mode and is used for outputting power of the motor body. The rigid main shaft is arranged in the hollow output shaft in an axial direction, and the two ends of the rigid main shaft extend to the outside of the motor body and are respectively connected with a pedal crank component. The pedal crank component is used for rotating synchronously with the hollow output shaft in an electric mode and rotating independently in a manual mode. The electromagnetic absorption assembly is arranged between the hollow output shaft and the rigid main shaft and is used for absorbing the hollow output shaft and the rigid main shaft to form a rigid connection in the electric mode. The motor is arranged in the hollow output shaft, the power of the motor body is directly transmitted to the rigid main shaft through the hollow output shaft, a direct-drive power structure is formed, the transmission efficiency is high, and the motor is not dragged in the manual mode.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and specifically to a direct-drive mid-mounted motor. Background Technology

[0002] Currently, the mid-drive motors widely used in two-wheeled vehicles such as electric bicycles and electric bicycles are mostly geared drive structures. They typically include the motor body, reduction mechanism, output shaft and clutch assembly. Power is reduced and increased in torque by the reduction mechanism, and then transmitted to the pedal spindle via transmission components such as sprockets, chains or belts.

[0003] Because power transmission involves multiple intermediate steps, it results in significant mechanical losses and low transmission efficiency. The complex structure of the reduction mechanism and chain drive components increases assembly and maintenance costs. In manual riding mode, the reduction mechanism and motor rotor still rotate with the pedal shaft, resulting in significant rotational inertia and mechanical resistance. Riders will clearly feel a dragging sensation, which affects the riding experience.

[0004] To address these issues, a direct-drive, mid-mounted motor is provided. Summary of the Invention

[0005] The purpose of this invention is to provide a direct-drive mid-drive motor, which solves the problems of existing mid-drive motors, which are mostly geared drive structures, resulting in low transmission efficiency, complex structure, and obvious dragging sensation when riding.

[0006] The present invention achieves the above objectives through the following technical solutions:

[0007] A direct-drive mid-mounted motor, comprising:

[0008] Motor body;

[0009] A hollow output shaft is rotatably mounted on the motor body and is used to output the power of the motor body.

[0010] A rigid spindle is axially inserted into the hollow output shaft, with both ends extending to the outside of the motor body and respectively connected to foot crank components. It is used to rotate synchronously with the hollow output shaft in electric mode and to rotate independently in manual mode.

[0011] An electromagnetic adsorption component is disposed between the hollow output shaft and the rigid main shaft, and is used to adsorb the hollow output shaft and the rigid main shaft in electric mode to form a rigid connection.

[0012] The electromagnetic adsorption assembly includes an armature ring axially slidably sleeved in the groove in the middle of the rigid spindle, an annular electromagnet fixedly disposed on the inner side of the hollow output shaft, and a plurality of circumferentially distributed reset members disposed on one side of the armature ring; the annular electromagnet and the armature ring are arranged opposite each other along the axial direction, and the reset members are used to push the armature ring to reset when the annular electromagnet is de-energized, so as to separate the hollow output shaft from the rigid spindle.

[0013] As a further optimization of the present invention, the motor also includes a power supply component for supplying power to the annular electromagnet; the power supply component includes a first conductive ring fixedly sleeved outside the hollow output shaft, and a second conductive ring fixedly mounted on the motor body by a bracket, wherein the first conductive ring and the second conductive ring form a sliding contact connection for supplying power to the annular electromagnet when the hollow output shaft is rotating.

[0014] As a further optimization of the present invention, the reset component includes a movable rod fixedly disposed on the armature ring and a spring sleeved on the movable rod; the movable rod is axially inserted into the guide hole of the rigid spindle, one end of the spring is fixedly connected to the rigid spindle, and the other end is fixedly connected to the armature ring.

[0015] As a further optimization of the present invention, the motor also includes a heat dissipation assembly for dissipating heat from the annular electromagnet. The heat dissipation assembly includes multiple heat dissipation ducts arranged axially on the hollow output shaft, and a heat dissipation fan disposed at the end of the hollow output shaft. The heat dissipation fan is embedded in the end cover of the motor body. The inner side of the hollow output shaft is provided with a mounting cavity for mounting the annular electromagnet. The heat dissipation ducts are connected to the mounting cavity to form an airflow channel when the heat dissipation fan is running, thereby performing directional blowing heat dissipation on the annular electromagnet.

[0016] As a further optimization of the present invention, the surface of the hollow output shaft is provided with a plurality of side air outlet holes that are connected to the heat dissipation duct, for guiding the cooling airflow in the heat dissipation duct to the motor body.

[0017] As a further optimization of the present invention, an annular heat sink is fixedly provided on the outer side of the annular electromagnet, and multiple heat dissipation fins are provided on both end faces of the annular electromagnet evenly distributed along the circumference.

[0018] As a further optimization of the present invention, the motor also includes a buffer assembly for reducing the impact force of the armature ring and the annular electromagnet adsorption; the buffer assembly includes an annular airbag sleeved on the outer peripheral surface of the armature ring, a first end toothed disc slidably disposed in the groove of the end face of the armature ring along the axial direction, a second end toothed disc fixedly disposed in the groove of the end face of the annular electromagnet, and a connecting pipe disposed between the first end toothed disc and the annular airbag for realizing the air pressure linkage between the two.

[0019] As a further optimization of the present invention, a plurality of telescopic members are provided on the inner end face of the first end gear disk, which are evenly distributed in the circumferential direction. One end of the telescopic member is fixedly disposed in the groove of the end face of the armature ring, and the other end is fixedly connected to the first end gear disk. A second reset member is provided in the telescopic member, which is used to assist the annular airbag in resetting after the annular electromagnet is de-energized.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. This invention places the rigid main shaft inside the hollow output shaft, and the power of the motor body is directly transmitted to the rigid main shaft through the hollow output shaft, forming a direct drive power structure. This eliminates the need for a chain or reducer, resulting in high transmission efficiency. The invention uses a ring electromagnet and an armature ring to achieve clutch engagement. In manual mode, the rigid main shaft and the hollow output shaft are completely separated, and the rider pedals without the inertial resistance of the motor, achieving manual riding without motor drag.

[0022] 2. The heat dissipation component of the present invention can not only efficiently and directionally cool the annular electromagnet through the heat dissipation air duct to prevent its performance from being affected by temperature rise, but also provide auxiliary heat dissipation to the inside of the motor body through the side air outlet on the surface of the hollow output shaft. When the hollow output shaft rotates, it drives the side air outlet to rotate synchronously, so that the ejected airflow forms a dynamic disturbance, breaks the hot air stagnation layer, and significantly improves the overall heat dissipation efficiency.

[0023] 3. The annular airbag of the buffer assembly of the present invention effectively solves the mechanical impact problem generated at the moment of electromagnetic attraction, significantly reducing vibration and abnormal noise. The annular airbag not only plays a buffering role, but also provides power for the axial movement of the first end gear plate. The meshing structure of the first end gear plate and the second end gear plate, together with the electromagnetic attraction of the armature ring and the annular electromagnet, form a dual connection mechanism of hollow output shaft and rigid main shaft. Compared with simple electromagnetic attraction, the transmission reliability is further improved. Attached Figure Description

[0024] Figure 1 This is a three-dimensional schematic diagram of the overall structure of the present invention;

[0025] Figure 2 This is a perspective view of the connection structure between the hollow output shaft and the rigid spindle of the present invention;

[0026] Figure 3 This is a cross-sectional view of the connection structure between the hollow output shaft and the rigid main shaft of the present invention;

[0027] Figure 4 This is a schematic diagram of the armature ring structure of the present invention;

[0028] Figure 5 This is a schematic diagram of the ring electromagnet structure of the present invention;

[0029] Figure 6 This is a schematic diagram of the hollow output shaft structure of the present invention;

[0030] Figure 7 This is a schematic diagram of the installation of the buffer component of the present invention;

[0031] Figure 8 This is a schematic diagram of the buffer component structure of the present invention.

[0032] In the picture:

[0033] 1. Motor body; 2. Hollow output shaft; 201. Heat dissipation duct; 202. Side air outlet; 203. Mounting cavity; 3. Rigid spindle; 4. Electromagnetic adsorption assembly; 401. Armature ring; 402. Ring electromagnet; 402a. Ring radiator; 402b. Heat dissipation fins; 403. Reset component; 403a. Movable rod; 403b. Spring; 5. Power supply assembly; 501. First conductive ring; 502. Second conductive ring; 6. Buffer assembly; 601. Ring airbag; 602. First end gear plate; 603. Second end gear plate; 604. Connecting pipe; 605. Telescopic component. Detailed Implementation

[0034] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0035] Example 1

[0036] To address the issues of low transmission efficiency, complex structure, and noticeable drag during riding that are common problems with existing mid-drive motors (mostly geared drive types), please refer to [link / reference]. Figures 1-3 The present invention provides a direct-drive mid-mounted motor, comprising:

[0037] Motor body 1;

[0038] The hollow output shaft 2 is rotatably mounted on the motor body 1 and is used to output the power of the motor body 1.

[0039] A rigid spindle 3 is axially inserted inside the hollow output shaft 2. Its two ends extend to the outside of the motor body 1 and are respectively connected to foot crank components. It is used to rotate synchronously with the hollow output shaft 2 in electric mode and to rotate independently in manual mode.

[0040] Electromagnetic adsorption component 4 is located between hollow output shaft 2 and rigid main shaft 3, and is used to adsorb hollow output shaft 2 and rigid main shaft 3 in electric mode to form a rigid connection.

[0041] The electromagnetic adsorption assembly 4 includes an armature ring 401 axially slidably sleeved in the groove in the middle of the rigid spindle 3, an annular electromagnet 402 fixedly disposed inside the hollow output shaft 2, and a plurality of circumferentially distributed reset members 403 disposed on one side of the armature ring 401; the annular electromagnet 402 and the armature ring 401 are arranged opposite each other in the axial direction, and the reset members 403 are used to push the armature ring 401 to reset when the annular electromagnet 402 is de-energized, so as to separate the hollow output shaft 2 from the rigid spindle 3.

[0042] A sealing assembly is provided at the junction of the hollow output shaft 2 and the rigid main shaft 3, specifically including an oil seal and a dustproof structure, to prevent external rainwater, dust and other impurities from entering. Furthermore, at least one set of bearing structures is provided between the hollow output shaft 2 and the rigid main shaft 3 to achieve relative rotational support between the two, ensuring the stability and smoothness of the hollow output shaft 2 remaining stationary while the rigid main shaft 3 rotates independently in manual mode. The above-mentioned oil seal and bearing structures are conventional technical means in this field, and their specific structures and arrangements can be referred to the relevant designs of existing mid-drive motors, which will not be elaborated here.

[0043] To address the issue that traditional fixed power supply methods cannot meet the power supply requirements of the toroidal electromagnet 402 in a rotating state, such as... Figure 2 As shown, the motor also includes a power supply component 5 for supplying power to the annular electromagnet 402. The power supply component 5 includes a first conductive ring 501 fixedly sleeved on the hollow output shaft 2, and a second conductive ring 502 fixed to the motor body 1 via a bracket. The first conductive ring 501 and the second conductive ring 502 form a sliding contact connection, used to supply power to the annular electromagnet 402 when the hollow output shaft 2 is rotating. This achieves rigid connection control between the hollow output shaft 2 and the rigid main shaft 3 in electric mode. The conductive slip ring structure ensures stable power supply to the annular electromagnet 402 in the rotating state, thereby ensuring the normal operation of the electromagnetic adsorption component 4.

[0044] like Figure 4 As shown, the reset component 403 includes a movable rod 403a fixedly mounted on the armature ring 401, and a spring 403b sleeved on the movable rod 403a. The movable rod 403a is axially inserted into the guide hole of the rigid spindle 3. One end of the spring 403b is fixedly connected to the rigid spindle 3, and the other end is fixedly connected to the armature ring 401. When the annular electromagnet 402 is de-energized, the spring 403b releases its elastic potential energy, pushing the armature ring 401 to move in the opposite direction axially. The movable rod 403a slides within the guide hole of the rigid spindle 3, ensuring the stability of the reset path of the armature ring 401. The armature ring 401 disengages from the contact state with the annular electromagnet 402, realizing the power separation between the hollow output shaft 2 and the rigid spindle 3.

[0045] In electric mode, the annular electromagnet 402 generates magnetic attraction when energized, attracting the armature ring 401 to move axially. The armature ring 401 adheres to the end face of the annular electromagnet 402, forming a rigid connection between the hollow output shaft 2 and the rigid main shaft 3. The power of the motor body 1 is directly transmitted to the rigid main shaft 3 through the hollow output shaft 2, driving the pedal crank component to rotate, forming a direct-drive power structure. In manual mode, the annular electromagnet 402 loses its magnetic attraction when de-energized, and the reset component 403 pushes the armature ring 401 to reset. The armature ring 401 disengages from the attraction surface of the annular electromagnet 402, and there is no rigid connection between the hollow output shaft 2 and the rigid main shaft 3. The rider pedals to drive the rigid main shaft 3 to rotate, while the hollow output shaft 2 and the motor body 1 remain stationary, achieving manual riding without motor drag.

[0046] Example 2

[0047] Based on Example 1, in order to solve the problem of heat generated by the annular electromagnet 402 during operation and to avoid heat accumulation affecting its performance, such as... Figures 5-6 As shown, the motor also includes a heat dissipation assembly for cooling the annular electromagnet 402. The heat dissipation assembly includes multiple heat dissipation air ducts 201 arranged axially on the hollow output shaft 2, and a cooling fan located at the end of the hollow output shaft 2. The cooling fan is embedded in the end cover of the motor body 1. The inner side of the hollow output shaft 2 is provided with a mounting cavity 203 for mounting the annular electromagnet 402. The heat dissipation air ducts 201 are connected to the mounting cavity 203 to form an airflow channel when the cooling fan is running, so as to perform directional blowing heat dissipation on the annular electromagnet 402.

[0048] Furthermore, the surface of the hollow output shaft 2 is provided with a plurality of side air outlet holes 202 that are connected to the heat dissipation duct 201, for guiding the cooling airflow in the heat dissipation duct 201 into the motor body 1.

[0049] Furthermore, an annular heat sink 402a is fixedly provided on the outer side of the annular electromagnet 402, and multiple circumferentially distributed heat dissipation fins 402b are provided on both end faces of the annular electromagnet 402. The annular heat sink 402a and the heat dissipation fins 402b together enhance the surface heat dissipation capacity of the annular electromagnet 402, and together with the heat dissipation components, form an efficient heat dissipation system to prevent the magnetic attraction performance of the annular electromagnet 402 from being affected by temperature rise. The annular heat sink 402a can be configured as a blade-type structure, including multiple circumferentially distributed heat dissipation blades, with airflow channels formed between adjacent heat dissipation blades. The cooling airflow in the heat dissipation duct 201 can directly pass through the airflow channels to enhance the convective heat transfer efficiency of the annular electromagnet 402 and achieve rapid heat dissipation.

[0050] When the toroidal electromagnet 402 is energized, it generates heat, which triggers the cooling fan to start. This causes air to flow along the cooling duct 201 on the hollow output shaft 2. The cooling airflow enters the mounting cavity 203 through the cooling duct 201 and blows directly onto the surface of the toroidal electromagnet 402. It then flows through the cooling fins 402b and the toroidal radiator 402a to achieve efficient convection cooling. At the same time, some of the airflow is discharged through the side exhaust vent 202 and enters the motor body 1 to cool key heat-generating components such as the stator winding and rotor. The hot air is then discharged through the heat dissipation holes in the motor housing.

[0051] Example 3

[0052] Based on Embodiments 1 and 2, in order to solve the problem of mechanical impact at the moment of electromagnetic attraction and avoid vibration or abnormal noise caused by attraction at low speeds or during start-stop, such as Figures 7-8 As shown, the motor also includes a buffer assembly 6 for reducing the impact force of the attraction between the armature ring 401 and the annular electromagnet 402; the buffer assembly 6 includes an annular airbag 601 sleeved on the outer peripheral surface of the armature ring 401, a first end gear 602 slidably disposed in the groove of the end face of the armature ring 401 along the axial direction, a second end gear 603 fixedly disposed in the groove of the end face of the annular electromagnet 402, and a connecting pipe 604 disposed between the first end gear 602 and the annular airbag 601 for realizing the pneumatic linkage between the two.

[0053] The inner end face of the first end gear 602 is provided with a plurality of telescopic members 605 evenly distributed in the circumferential direction. One end of the telescopic member 605 is fixedly disposed in the groove on the end face of the armature ring 401, and the other end is fixedly connected to the first end gear 602. The telescopic member 605 is provided with a second reset member, which is used to assist the annular airbag 601 in resetting after the annular electromagnet 402 is de-energized, so that the first end gear 602 disengages from the meshing state with the second end gear 603, thereby realizing the power separation between the hollow output shaft 2 and the rigid main shaft 3.

[0054] When the annular electromagnet 402 is energized and attracts the armature ring 401, the annular airbag 601 is compressed, absorbing some of the impact energy and preventing vibration or abnormal noise from the engagement. Simultaneously, the connecting pipe 604, through the telescopic member 605, pushes the first end gear 602 to extend axially, so that it engages and locks with the second end gear 603, achieving a rigid connection between the hollow output shaft 2 and the rigid main shaft 3. When the annular electromagnet 402 is de-energized, the annular airbag 601 returns to its original shape under its own restoring force and the elastic potential energy of the second restoring member, pushing the first end gear 602 back to the armature ring 401. Within the end face groove of shaft 1, the hollow output shaft 2 is disconnected from the rigid main shaft 3, enabling drag-free riding. The annular airbag 601 not only acts as a buffer but also provides power for the axial movement of the first end gear 602, pushing it to mesh with the second end gear 603 to achieve a rigid transmission connection. The meshing structure of the first end gear 602 and the second end gear 603, together with the electromagnetic attraction of the armature ring 401 and the annular electromagnet 402, forms a dual connection mechanism between the hollow output shaft 2 and the rigid main shaft 3. Compared with simple electromagnetic attraction, the transmission reliability is further improved.

[0055] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A direct-drive mid-mounted motor, characterized in that, include: Motor body (1); A hollow output shaft (2) is rotatably mounted on the motor body (1) and is used to output the power of the motor body (1); A rigid spindle (3) is axially inserted inside the hollow output shaft (2), with both ends extending to the outside of the motor body (1) and connected to foot crank components, for rotating synchronously with the hollow output shaft (2) in electric mode and rotating independently in manual mode; An electromagnetic adsorption component (4) is disposed between the hollow output shaft (2) and the rigid main shaft (3) for adsorbing the hollow output shaft (2) and the rigid main shaft (3) in electric mode to form a rigid connection. The electromagnetic adsorption assembly (4) includes an armature ring (401) axially slidably sleeved in the middle groove of the rigid main shaft (3), an annular electromagnet (402) fixedly disposed on the inner side of the hollow output shaft (2), and a plurality of circumferentially distributed reset members (403) disposed on one side of the armature ring (401). The annular electromagnet (402) and the armature ring (401) are arranged opposite each other along the axial direction. The reset member (403) is used to push the armature ring (401) to reset when the annular electromagnet (402) is de-energized, so as to separate the hollow output shaft (2) from the rigid main shaft (3). The reset component (403) includes a movable rod (403a) fixedly mounted on the armature ring (401) and a spring (403b) sleeved on the movable rod (403a); the movable rod (403a) is axially inserted into the guide hole of the rigid spindle (3), one end of the spring (403b) is fixedly connected to the rigid spindle (3), and the other end is fixedly connected to the armature ring (401); The motor also includes a buffer assembly (6) for reducing the impact force of the armature ring (401) and the annular electromagnet (402) attraction. The buffer assembly (6) includes an annular airbag (601) sleeved on the outer peripheral surface of the armature ring (401), a first end toothed disc (602) slidably disposed in the groove of the end face of the armature ring (401) along the axial direction, a second end toothed disc (603) fixedly disposed in the groove of the end face of the annular electromagnet (402), and a connecting pipe (604) disposed between the first end toothed disc (602) and the annular airbag (601) for realizing the air pressure linkage between the two. The inner end face of the first end gear plate (602) is provided with a plurality of telescopic members (605) evenly distributed in the circumferential direction. One end of the telescopic member (605) is fixedly disposed in the groove of the end face of the armature ring (401), and the other end is fixedly connected to the first end gear plate (602). The telescopic member (605) is provided with a second reset member, which is used to assist the annular airbag (601) in resetting after the annular electromagnet (402) is de-energized.

2. The direct-drive mid-mounted motor according to claim 1, characterized in that, The motor also includes a power supply assembly (5) for supplying power to the ring electromagnet (402); The power supply component (5) includes a first conductive ring (501) fixedly sleeved outside the hollow output shaft (2) and a second conductive ring (502) fixedly mounted on the motor body (1) by a bracket. The first conductive ring (501) and the second conductive ring (502) form a sliding contact connection for supplying power to the annular electromagnet (402) when the hollow output shaft (2) is rotating.

3. A direct-drive mid-mounted motor according to claim 1, characterized in that, The motor also includes a heat dissipation assembly for dissipating heat from the annular electromagnet (402), the heat dissipation assembly including multiple heat dissipation air ducts (201) arranged axially on the hollow output shaft (2), and a heat dissipation fan arranged at the end of the hollow output shaft (2), the heat dissipation fan being embedded in the end cover of the motor body (1). The hollow output shaft (2) has an inner cavity (203) for mounting an annular electromagnet (402). The heat dissipation duct (201) is connected to the mounting cavity (203) to form an airflow channel when the cooling fan is running, so as to perform directional blowing heat dissipation on the annular electromagnet (402).

4. A direct-drive mid-mounted motor according to claim 3, characterized in that, The hollow output shaft (2) has multiple side air outlets (202) connected to the heat dissipation duct (201) on its surface, which are used to guide the cooling airflow in the heat dissipation duct (201) into the motor body (1).

5. A direct-drive mid-mounted motor according to claim 4, characterized in that, An annular heat sink (402a) is fixedly provided on the outer side of the annular electromagnet (402), and multiple heat dissipation fins (402b) are provided on both end faces of the annular electromagnet (402) evenly distributed along the circumference.

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