A two-speed wheel hub motor capable of automatic gear shifting and vehicle

Abstract

The application discloses a two-speed wheel hub motor capable of automatic gear shifting and a vehicle, and relates to the field of wheel hub motors. Technical scheme points of the application include a main shaft, a wheel hub and an end cover connected with each other are supported on the main shaft in a rolling manner, a machine core assembly is arranged on the main shaft, the machine core assembly comprises a first rotor and a second rotor connected with each other, a first gear planetary reduction assembly connected between the first rotor and the wheel hub and a second gear planetary reduction assembly connected between the second rotor and the end cover are arranged on the main shaft respectively, the second gear planetary reduction assembly comprises a centrifugal driving assembly connected with the end cover, and the centrifugal driving assembly controls transmission between the second rotor and the end cover according to the rotating speed of the end cover. The application can automatically realize switching of two gears, improve riding experience and prolong service life.

Description

Technical Field

[0001] This invention relates to the field of hub motors, and more specifically, to a two-speed hub motor and vehicle capable of automatic gear shifting. Background Technology

[0002] Currently, most electric-assist bicycles on the market use hub motors with two structural types: direct drive and gear reduction. In a direct drive motor, the rotor is the wheel hub, while in a gear reduction motor, the rotor is fed to the wheel hub via a gear reduction mechanism. Neither of these structures has mechanical speed change capability, making it impossible to convert the motor's output torque into speed, resulting in low operating efficiency.

[0003] A Chinese patent with authorization announcement number CN211995141U discloses an electric vehicle hub motor, which includes a hub body and a fixed shaft. A motor, a fixed-axis gear train assembly, and a centrifugal clutch structure are mounted on the fixed shaft. The fixed-axis gear train assembly is mounted on the right end cover of the motor's motion output via an overrunning clutch, and the centrifugal clutch structure is mounted on the left end cover of the motor's motion output. When the motor rotates in one direction, it drives the fixed-axis gear train assembly to rotate the hub body via the overrunning clutch, and the centrifugal clutch structure is in a disengaged state. When the motor rotates in another direction, it drives the hub body to rotate via the centrifugal clutch structure, and the overrunning clutch is in a disengaged state.

[0004] Although the aforementioned electric vehicle hub motor includes two gears, low and high, switching gears requires changing the direction of the motor's rotation, making it impossible to achieve automatic gear shifting while riding.

[0005] A Chinese patent with publication number CN1112071160A discloses an internal swing-type centrifugal clutch, which includes a central shaft, a motor and a hub. The left side of the motor is connected to the left inner cover of the motor via an overrunning clutch and a planetary assembly. The outer side of the planetary assembly is connected to a brake via a left end cover. The right side of the motor is connected to an internal swing-type centrifugal clutch via a right inner cover of the motor. The outer side of the internal swing-type centrifugal clutch is connected to a right end cover. Both the right and left end covers are connected to the hub.

[0006] In the aforementioned internal swing-block centrifugal clutch, at low speed, the motor drives the left end cover to rotate through the overrunning clutch and planetary assembly, thereby driving the wheel hub to move at low speed; at high speed, the motor's right inner cover drives the internal swing-block mechanism to rotate, thereby driving the right end cover to move at high speed.

[0007] However, in the two hub motor structures mentioned above, a gear reduction motor structure is formed at low speeds, while a direct drive motor structure is formed at high speeds. The difference in transmission ratio between low and high speed states is large, which affects operating efficiency on the one hand, and the sudden increase in speed during riding can easily lead to safety accidents, affecting the riding experience and service life.

[0008] Furthermore, in both of the aforementioned hub motor structures, the centrifugal clutch is connected to the motor, meaning its operation is controlled by the motor's rotational speed. However, with the aforementioned internal swing-block centrifugal clutch, when the electric vehicle is going downhill or coasting and doesn't need to start, the hub remains at high speed, the overrunning clutch is in overrunning mode, the motor doesn't rotate, and the centrifugal clutch resets to its initial state. When the rider starts again, if the hub is still at high speed, the motor rotates, first engaging the overrunning clutch to enter a low gear, and then switching to a high gear. This frequent gear switching not only affects the riding experience but also easily leads to component failure and shortens the lifespan of the vehicle. Summary of the Invention

[0009] In view of the shortcomings of the existing technology, one of the objectives of the present invention is to provide a two-speed hub motor that can automatically switch between two gears, improve the riding experience, and extend the service life.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] A two-speed hub motor capable of automatic gear shifting includes a main shaft, on which a hub and an end cap are rolledly supported and connected to each other. A core assembly is disposed on the main shaft, and the core assembly includes a first rotor and a second rotor connected to each other.

[0012] The main shaft is respectively provided with a first-gear planetary reduction assembly connected between the first rotor and the hub, and a second-gear planetary reduction assembly connected between the second rotor and the end cover;

[0013] The second planetary reduction gear assembly includes a centrifugal drive assembly connected to the end cover, which controls the transmission between the second rotor and the end cover according to the rotational speed of the end cover.

[0014] Furthermore, the first planetary deceleration assembly includes:

[0015] The first sun gear is fixedly connected to the first rotor;

[0016] A planetary clutch mounted on the main shaft, wherein a first planetary gear meshes with the first sun gear; and

[0017] A first internal gear ring is fixedly disposed inside the hub and meshes with the first planetary gear.

[0018] Furthermore, the second planetary deceleration assembly includes:

[0019] The second sun gear is fixedly connected to the second rotor;

[0020] A planet carrier is fitted onto the main shaft, and a second planet gear that meshes with the second sun gear is provided on the planet carrier;

[0021] The second internal gear ring meshes with the second planetary gear; and,

[0022] A clutch assembly positioned between the second internal gear ring and the end cap;

[0023] The centrifugal drive assembly restricts and releases the clutch assembly according to the rotational speed of the end cover, thereby controlling the transmission between the second rotor and the end cover.

[0024] Furthermore, the clutch assembly includes an inner clutch ring, an outer clutch ring, and a clutch drive member and an elastic member disposed between the two. The inner clutch ring is circumferentially linked with the end cover, and the outer clutch ring is circumferentially linked with the second internal gear ring.

[0025] Furthermore, a transmission frame that is fixedly provided on the second internal gear ring and is circumferentially linked with the outer clutch ring is provided.

[0026] Furthermore, the centrifugal drive assembly includes a centrifugal block and a limiting plate. The limiting plate is provided with a release groove that cooperates with the clutch drive component. A shaft connected to the end cover passes through the centrifugal block.

[0027] When the centrifugal block is in the contracted state, the limiting plate restricts the clutch drive, preventing the inner clutch ring and the outer clutch ring from being transmitted through the clutch drive; after the centrifugal block rotates and swings out around the shaft, it drives the limiting plate to rotate, causing the clutch drive to be embedded in the release groove, thereby allowing the outer clutch ring and the inner clutch ring to be transmitted through the clutch drive.

[0028] Furthermore, the centrifugal block is provided with a swing arm for driving the limiting plate to rotate.

[0029] Furthermore, the number of centrifuge blocks is at least two, and the centrifugation drive assembly also includes an elastic reset member connected only to one of the centrifuge blocks.

[0030] Furthermore, a fixed seat is fixedly provided on the inner end wall of the end cap, which is connected to the centrifugal drive assembly and the clutch inner ring. The fixed seat can radially limit the centrifugal block.

[0031] Another object of the present invention is to provide a vehicle comprising the above-mentioned two-speed hub motor. Specifically, the vehicle may be a vehicle for riding, including electric bicycles and electric vehicles (including two-wheeled, three-wheeled and four-wheeled vehicles), or a vehicle for transportation, including electric transport vehicles and electric transport racks, or an electric wheelchair, etc., without limitation.

[0032] In summary, the present invention has the following beneficial effects:

[0033] 1. The use of first-gear planetary reduction assembly and second-gear planetary reduction assembly can effectively control the transmission ratio difference between first gear and second gear, thereby optimizing driving safety and riding experience;

[0034] 2. Connecting the centrifugal drive assembly to the end cap used for output speed can reduce the frequency of gear shifting, extend service life, optimize the riding experience, and obtain a smoother gear shifting experience.

[0035] 3. This invention provides mechanical speed change for the hub motor output, realizing the conversion between torque and speed through mechanical speed change, enabling the motor to operate and output within the high-efficiency range, thereby improving operating efficiency. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the overall structure of a two-speed hub motor capable of automatic gear shifting in Embodiment 1;

[0037] Figure 2 This is an exploded schematic diagram of a two-speed hub motor capable of automatic gear shifting in Example 1;

[0038] Figure 3 This is a cross-sectional view of the second planetary deceleration assembly in Example 1;

[0039] Figure 4 This is a schematic diagram of the centrifugal drive assembly in Example 1. Figure 1 ;

[0040] Figure 5 This is a schematic diagram of the centrifugal drive assembly in Example 1. Figure 2 .

[0041] In the diagram: 1. Main shaft; 21. Hub; 22. End cover; 31. First rotor; 32. Second rotor; 4. First gear planetary reduction assembly; 5. Second gear planetary reduction assembly; 511. Second sun gear; 512. Planet carrier; 513. Second planet gear; 514. Second internal gear ring; 515. Positioning bearing; 52. Transmission frame; 531. Pawl seat; 532. Pawl; 533. Ratchet; 541. Fixed seat; 542. Centrifugal block; 5421. Shaft; 5422. Pin; 543. Limiting plate; 5431. Release groove; 5432. Limiting groove; 5433. Drive hole; 544. Swing arm; 5441. Drive rod. Detailed Implementation

[0042] The present invention will be further described in detail below with reference to the accompanying drawings.

[0043] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

[0044] Example 1:

[0045] A two-speed hub motor capable of automatic gear shifting, see reference Figures 1 to 5 The device includes a main shaft 1, on which a hub 21 and an end cover 22 are rolled and connected. The hub 21 and the end cover 22 are connected to form a complete housing for outputting rotational speed. A core assembly is provided on the main shaft 1. The core assembly includes a first rotor 31 and a second rotor 32 connected to each other. The first rotor 31 and the second rotor 32 are connected by screws to achieve synchronous rotation for inputting the initial rotational speed. The core assembly also includes a stator fixedly sleeved on the main shaft 1. A first-gear planetary reduction assembly 4 is provided on the main shaft 1, connecting the first rotor 31 and the hub 21, and a second-gear planetary reduction assembly 5 is provided, connecting the second rotor 32 and the end cover 22. The second-gear planetary reduction assembly 5 includes a centrifugal drive assembly connected to the end cover 22. The centrifugal drive assembly controls the transmission between the second rotor 32 and the end cover 22 according to the rotational speed of the end cover 22.

[0046] Reference Figure 2 The first-gear planetary reduction assembly 4 includes a first sun gear, a planetary clutch, and a first internal gear ring. The first sun gear is fixedly connected to the first rotor 31 by screws, and the first internal gear ring is fixedly embedded in the hub 21. The planetary clutch is provided with a first planetary gear that meshes with the first sun gear and the first internal gear ring. In this embodiment, the planetary clutch is connected to the main shaft 1 by a keyway. The planetary clutch is existing technology and will not be described in detail here.

[0047] Reference Figures 2 to 5 The second planetary reduction gear assembly includes a second sun gear 511, a planet carrier 512, and a second internal gear ring 514. The second sun gear 511 is fixedly connected to the second rotor 32 by screws, and the planet carrier 512 is fixedly connected to the main shaft 1 by a keyway. The planet carrier 512 is provided with a second planet gear 513 that meshes with the second sun gear 511 and the second internal gear ring 514. In this embodiment, a positioning bearing 515 is provided between the planet carrier 512 and the second internal gear ring 514 to position the second internal gear ring 514. A clutch assembly is provided between the second internal gear ring 514 and the end cover 22. The centrifugal drive assembly restricts and releases the clutch assembly according to the rotation speed of the end cover 22, thereby controlling the transmission between the second rotor 32 and the end cover 22.

[0048] Reference Figure 3 and Figure 5The clutch assembly includes an inner clutch ring, an outer clutch ring, and a clutch drive component and an elastic component disposed between the two. The inner clutch ring is circumferentially linked with the end cover 22, and the outer clutch ring is circumferentially linked with the second internal gear ring 514. In this embodiment, the clutch assembly adopts a ratchet and pawl assembly. In other optional embodiments, a clutch such as a one-way bearing can also be used, which is not limited here. Specifically, the inner clutch ring is a pawl seat 531, the outer clutch ring is a ratchet 533, the clutch drive component is a pawl 532, and the elastic component is a spring ring. In this embodiment, the end of the second internal gear ring 514 is fixedly provided with a transmission frame 52 that is circumferentially linked with the ratchet 533. The ratchet 533 is embedded in the transmission frame 52. Specifically, the inner side wall of the transmission frame 52 and the outer side wall of the ratchet 533 are respectively provided with spaced protrusions (not shown in the figure). The two achieve circumferential transmission through the protrusions, and at the same time, they can also play a buffering role to improve the riding experience.

[0049] Reference Figures 3 to 5 The centrifugal drive assembly includes a centrifugal block 542 and a limiting plate 543. The limiting plate 543 has a release groove 5431 that engages with a pawl 532. A shaft 5421 connected to the end cover 22 passes through the centrifugal block 542. When the centrifugal block 542 is in the retracted state, the limiting plate 543 restricts the pawl 532, preventing the pawl seat 531 and ratchet 533 from transmitting power through the pawl 532. After the centrifugal block 542 rotates around the shaft 5421 and swings open, it drives the limiting plate 543 to rotate, causing the pawl 532 to engage with the release groove 5431. The ratchet seat 531 and the ratchet wheel 533 are driven by the ratchet 532. Under the elastic force of the spring coil, the meshing end of the ratchet 532 can be lifted and mesh with the ratchet wheel 533. The limiting plate 543 restricts the ratchet 532 by pressing down its meshing end so that it cannot be lifted. Specifically, in this embodiment, the limiting plate 543 is provided with a limiting groove 5432 that cooperates with the meshing end of the ratchet 532. Of course, in other optional embodiments, the ratchet 532 can also be pressed down directly by the inner side wall of the limiting plate 543. This is not a limitation.

[0050] Reference Figure 5 The centrifugal block 542 is provided with a swing arm 544 for driving the limiting plate 543 to rotate. Specifically, the centrifugal block 542 and the swing arm 544 are fixedly connected by a pin 5422, that is, the swing arm 544 is equivalent to an extension arm of the centrifugal block 542. The swing arm 544 is provided with a drive rod 5441, and the limiting plate 543 is provided with a drive hole 5433 that cooperates with the drive rod 5441. In this embodiment, after the centrifugal block 542 rotates and swings away around the shaft 5421, the swing arm 544 rotates synchronously, and then drives the limiting plate 543 to rotate through the drive rod 5441. The setting of the swing arm 544 is beneficial to controlling the size of the limiting plate 543. In other optional embodiments, the centrifugal block 542 can also directly drive the limiting plate 543 to rotate, which is not limited here.

[0051] Reference Figure 5 In this embodiment, there are two centrifugal blocks 542. The centrifugal drive assembly also includes an elastic reset member connected to only one of the centrifugal blocks 542. In this embodiment, the elastic reset member is a torsion spring (not shown in the figure). The elastic force of the torsion spring makes the centrifugal block 542 tend to reset to the contracted state. There are two centrifugal blocks 542. If one centrifugal block 542 fails to reset accurately, the limiting plate 543 will not be able to reset accurately. There may be differences between torsion springs of the same specification. Therefore, only one torsion spring is set to promote the reset of the centrifugal block 542, which can ensure the accurate reset of the limiting plate 543, thereby ensuring a smooth switch between the limiting and releasing states.

[0052] Reference Figures 3 to 5 In this embodiment, a fixing seat 541 is fixedly provided on the inner end wall of the end cap 22, which is connected to the centrifugal drive assembly and the ratchet seat 531. The fixing seat 541 can radially limit the centrifugal block 542. Specifically, the fixing seat 541 and the end cap 22, as well as the fixing seat 541 and the ratchet seat 531, are fixedly connected by screws. The shaft 5421 on the centrifugal block 542 is embedded in the inner end wall of the fixing seat 541, and the fixing seat 541 includes a circumferential side wall that can radially limit the centrifugal block 542. In other optional embodiments, the fixing seat 541 can also be integrally formed with the end cap 22. However, in this embodiment, the separate structure design of the fixing seat 541 and the end cap 22 facilitates assembly and maintenance.

[0053] The working principle is as follows:

[0054] When the motor is in the starting stage, it needs to decelerate and increase torque. The first rotor 31 drives the hub 21 to rotate through the first planetary reduction assembly 4 to achieve power output. At this time, the speed of the hub 21 and the end cover 22 has not reached the speed change point, so the centrifugal block 542 is in the retracted state, and the clutch assembly cannot transmit power. Therefore, the speed of the second rotor 32 cannot be transmitted to the end cover.

[0055] In second-speed mode, the motor needs to increase speed and decrease torque. When the speed of hub 21 and end cover 22 reaches the shift point, centrifugal block 542 rotates to the open state, and clutch assembly switches to the engaged state. Then the speed of second rotor 32 is transmitted to end cover 22 through second-speed planetary reduction assembly 5 to achieve power output. The speed of second rotor 32 output to end cover 22 after passing through second-speed planetary reduction assembly 5 is greater than the speed of first rotor 31 output to hub 21 after passing through first-speed planetary reduction assembly 4. Therefore, in second-speed mode, planetary clutch is in overrunning state.

[0056] When the vehicle is going downhill or coasting and does not need to start, the hub 21 and end cover 22 remain at high speed. At this time, the planetary clutch and clutch assembly are in overrunning state, and the first rotor 31 and the second rotor 32 do not rotate. When the hub 21 and end cover 22 are in high speed and restarted, the centrifugal block 542 remains in the swing-out state according to the rotation speed of the end cover 22. The motor continues to work directly in second gear without needing to switch gears, thereby reducing the number of gear shifts, extending the service life of the motor, and improving the riding experience.

[0057] Example 2:

[0058] A vehicle includes the two-speed hub motor of Embodiment 1. Specifically, the vehicle can be a vehicle for riding, including electric bicycles and electric vehicles (including two-wheeled, three-wheeled and four-wheeled vehicles), or a vehicle for transportation, including electric transport vehicles and electric transport racks, or an electric wheelchair, etc., without limitation.

Claims

1. A two-speed hub motor capable of automatic gear shifting, comprising a main shaft, on which a hub and an end cap are rolledly supported and interconnected, and a core assembly is disposed on the main shaft, the core assembly comprising a first rotor and a second rotor connected to each other; characterized in that: The main shaft is respectively provided with a first-gear planetary reduction assembly connected between the first rotor and the hub, and a second-gear planetary reduction assembly connected between the second rotor and the end cover; The second planetary reduction gear assembly includes a centrifugal drive assembly connected to the end cover, wherein the centrifugal drive assembly controls the transmission between the second rotor and the end cover according to the output speed of the end cover; The second-gear planetary deceleration assembly includes: The second sun gear is fixedly connected to the second rotor; A planet carrier is fitted onto the main shaft, and a second planet gear that meshes with the second sun gear is provided on the planet carrier; The second internal gear ring meshes with the second planetary gear; and, A clutch assembly positioned between the second internal gear ring and the end cap; The centrifugal drive assembly restricts and releases the clutch assembly according to the rotational speed of the end cover, thereby controlling the transmission between the second rotor and the end cover; The clutch assembly includes an inner clutch ring, an outer clutch ring, and a clutch drive component and an elastic component disposed between the two. The inner clutch ring is circumferentially linked with the end cover, and the outer clutch ring is circumferentially linked with the second internal gear ring. A transmission frame that is circumferentially linked with the clutch outer ring is fixedly provided on the second internal gear ring; The centrifugal drive assembly includes a centrifugal block and a limiting plate. The limiting plate is provided with a release groove that cooperates with the clutch drive component. A shaft connected to the end cover passes through the centrifugal block. When the centrifugal block is in the contracted state, the limiting plate restricts the clutch drive, preventing the inner clutch ring and the outer clutch ring from being transmitted through the clutch drive; after the centrifugal block rotates and swings out around the shaft, it drives the limiting plate to rotate, causing the clutch drive to be embedded in the release groove, thereby allowing the outer clutch ring and the inner clutch ring to be transmitted through the clutch drive.

2. The two-speed hub motor capable of automatic gear shifting according to claim 1, characterized in that: The first planetary deceleration assembly includes: The first sun gear is fixedly connected to the first rotor; A planetary clutch mounted on the main shaft, wherein a first planetary gear meshes with the first sun gear; and A first internal gear ring is fixedly disposed inside the hub and meshes with the first planetary gear.

3. The two-speed hub motor capable of automatic gear shifting according to claim 1, characterized in that: The centrifugal block is equipped with a swing arm for driving the limiting plate to rotate.

4. The two-speed hub motor capable of automatic gear shifting according to claim 1, characterized in that: The number of centrifuge blocks is at least two, and the centrifugation drive assembly also includes a resilient reset member that is connected only to one of the centrifuge blocks.

5. The two-speed hub motor capable of automatic gear shifting according to claim 1, characterized in that: The inner end wall of the end cap is fixedly provided with a fixing seat that is connected to the centrifugal drive assembly and the clutch inner ring. The fixing seat can radially limit the centrifugal block.

6. A vehicle, characterized in that: Includes the two-speed hub motor according to any one of claims 1-5.

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