Hub motor gearbox and hub motor speed changing method

Abstract

The invention discloses a hub motor gearbox and a hub motor speed changing method, and relates to the technical field of electric vehicles, the hub motor gearbox is connected in a wheel frame, the hub motor gearbox comprises a hub motor rotor, a hub motor stator, a planetary gear set, a ratchet mechanism, a gear ring and a clutch assembly; the outer peripheral side wall of the hub motor rotor is connected with the inner peripheral side wall of the wheel frame through the ratchet mechanism; the hub motor stator is arranged in the hub motor rotor; the hub motor stator is provided with a rotating shaft, and the rotating shaft penetrates through the hub motor rotor and extends to the outside of the wheel frame; the gear ring is fixedly connected to the inner circumferential side wall of the wheel frame, and the gear ring is in meshing transmission with the planet wheel. According to the invention, the technical effect of switching high and low gears can be realized.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle technology, and more specifically to a hub motor gearbox and a hub motor speed change method. Background Technology

[0002] Currently, most electric bicycles sold and used on the market use hub motors, which are simple in structure and low in cost. However, this drive system has a common drawback: low torque and poor climbing ability. The main reason is that the hub motors used in electric bicycles have relatively low power, resulting in low torque. Furthermore, as the battery voltage decreases during use, its output power and torque also drop significantly. To achieve better climbing ability, a higher-power hub motor is needed, requiring a more powerful motor speed controller, which increases costs. At the same time, the new national standard imposes strict speed limits on electric bicycles, preventing the full performance advantages of high-power motors from being realized. This leads manufacturers to avoid using high-power motors due to cost and practicality considerations.

[0003] However, electric bicycles used in daily life frequently face the challenge of climbing hills. For example, many underground parking garages in residential areas and some large bridges on city roads present very steep inclines for electric bicycles. Currently, most electric bicycle owners can only rely on pushing the bicycle when faced with steep slopes. A small number of owners can manage to climb hills by using higher motor power and torque, or with a fully charged battery. In some mountainous cities, residents using electric bicycles basically have to rely on models with high-powered motors to climb hills.

[0004] In existing patent CN105711712A, the tire is fixedly mounted on the wheel hub, a second wheel hub support is mounted on one end of the inner side of the wheel hub, and the second wheel hub support is fixed on the rear wheel axle. The rear wheel axle is mounted on the output end of the overrunning clutch, which is mounted on the output shaft of the hydraulic torque converter. The hydraulic torque converter is mounted on the hub motor via a hydraulic torque converter support, and the hub motor shaft is connected to the input shaft of the hydraulic torque converter. The hub motor is mounted on one end of the motor fixed shaft via a motor mounting plate. However, because a planetary gear set is lacking in the transmission, it is impossible to switch between high and low speeds. By increasing the torque through a planetary gear set and coordinating with the clutch assembly to control the transmission or disengagement of the hub motor rotor torque, the corresponding technical problem in CN105711712A can be solved.

[0005] Therefore, how to provide a wheel hub motor gearbox and wheel hub motor speed change method for switching between high and low speeds is one of the technical problems that urgently need to be solved in this field. Summary of the Invention

[0006] In view of the above, the present invention provides a hub motor gearbox and a hub motor speed change method. The purpose of this invention is to address the aforementioned shortcomings.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A hub motor gearbox is connected within a wheel frame. The hub motor gearbox includes: a hub motor rotor, a hub motor stator, a planetary gear set, a ratchet mechanism, a gear ring, and a clutch assembly. The outer peripheral sidewall of the hub motor rotor is connected to the inner peripheral sidewall of the wheel frame through the ratchet mechanism; The stator of the hub motor is disposed inside the rotor of the hub motor; The hub motor stator is provided with a rotating shaft, which extends through the hub motor rotor to the outside of the wheel frame; The planetary gear set includes a sun gear and planet gears; the rotating shaft passes through the axis of the sun gear, and a gap is left between the rotating shaft and the sun gear; the sun gear is driven or disengaged from the hub motor rotor through the clutch assembly; the sun gear meshes with the planet gears for transmission. The gear ring is fixedly connected to the inner circumferential side wall of the wheel frame, and the gear ring meshes with the planetary gear for transmission.

[0008] Preferably, the ratchet mechanism includes: a ratchet, a pawl, an auxiliary ring, and a compression spring; The ratchet is fixedly connected to the inner peripheral sidewall of the wheel frame; The auxiliary ring is fixedly connected to the outer peripheral sidewall of the hub motor rotor; The outer peripheral sidewall of the auxiliary ring is provided with a spring-loaded groove; One end of the bottom wall of the spring-loaded groove is hinged to the pawl, and the other end of the bottom wall of the spring-loaded groove is press-fitted with one side of the compression spring; the other side of the compression spring is press-fitted with the bottom surface of the pawl.

[0009] Preferably, the hub motor rotor is configured in a funnel shape; the hub motor rotor has a neck on the side facing the planetary gear set.

[0010] Preferably, the pivot extends through the neck to the outside of the wheel frame.

[0011] Preferably, the clutch assembly includes: a sliding connecting tube, a fixed tube, and ball bearings; Both the sliding connecting tube and the fixed tube are sleeved on the rotating shaft; The outer peripheral sidewall of the sliding connecting pipe is provided with a sliding groove; The inner circumferential sidewall of the tube neck is provided with a spherical groove; The ball is rolled within the spherical groove, and simultaneously slides within the slide groove; One end of the fixed tube is fixedly connected to the sun gear; The other end of the fixed tube is engaged with or separated from the end of the sliding connecting tube.

[0012] A method for speed change of a hub motor includes the following steps: S1. When the vehicle needs to travel at high speed, the rotor of the hub motor reverses, the pawl slides in the ratchet, the sliding connecting tube is locked with the fixed tube, driving the sun gear to rotate, and then driving the ring gear to rotate through the planetary gears, thereby driving the wheel frame to rotate. S2. When the vehicle needs to travel at low speed, the hub motor rotor rotates forward, the pawl is engaged in the ratchet, and the sliding connecting pipe is separated from the fixed pipe; the hub motor rotor drives the wheel frame to rotate through the pawl and the ratchet.

[0013] The present invention achieves the following technical effects compared to the prior art: 1. The outer peripheral sidewall of the hub motor rotor is connected to the inner peripheral sidewall of the wheel frame via the ratchet mechanism. The sun gear meshes with the planetary gears for transmission. The gear ring is fixedly connected to the inner peripheral sidewall of the wheel frame, and meshes with the planetary gears for transmission. The sun gear is driven or disengaged from the hub motor rotor via the clutch assembly. When the hub motor rotor is driven by the sun gear via the clutch assembly, the torque increases through the sun gear and the planetary gears, driving the gear ring to rotate, thereby achieving high-speed switching. When the hub motor rotor is disengaged from the sun gear, the torque of the hub motor rotor directly acts on the wheel frame, thereby achieving low-speed switching. 2. The auxiliary ring is fixedly connected to the outer peripheral sidewall of the hub motor rotor; the outer peripheral sidewall of the auxiliary ring is provided with a spring-loaded groove; one end of the bottom wall of the spring-loaded groove is hinged to the pawl, and the other end of the bottom wall of the spring-loaded groove is pressed into one side of the compression spring, and the other side of the compression spring is pressed into the bottom surface of the pawl. The compression spring provides a pushing force. When the hub motor rotor rotates forward, the ratchet tooth inclined sliding surface of the ratchet slides with the pawl inclined sliding surface, thereby realizing the pawl sliding in the ratchet; when the hub motor rotor rotates in reverse, the obtuse angle surface of the ratchet tooth is locked with the obtuse angle surface of the pawl, thereby realizing the pawl being locked in the ratchet, so that the torque of the hub motor rotor directly acts on the wheel frame; 3. Both the sliding connecting tube and the fixed tube are sleeved on the rotating shaft; the outer peripheral sidewall of the sliding connecting tube is provided with a sliding groove; the ball bearing is rolled in the spherical groove, and at the same time, the ball bearing slides in the sliding groove; one end of the fixed tube is fixedly connected to the sun gear; the other end of the fixed tube is engaged or disengaged from the end of the sliding connecting tube; the rotation of the tube neck provides inertia to the sliding connecting tube, pushing the sliding connecting tube to slide horizontally on the rotating shaft; the sliding connecting tube slides close to the fixed tube to engage, or the sliding connecting tube slides away from the fixed tube to disengage. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the planetary gear set structure of the present invention; Figure 3 This is a schematic diagram of the ratchet mechanism structure of the present invention; Figure 4 For the present invention Figure 3 Enlarged view of point A; Figure 5 This is a schematic diagram of the sliding connecting tube and the fixed tube of the present invention; Figure 6 This is a schematic diagram of the clutch assembly structure of the present invention; Figure 7 This is a schematic diagram of Embodiment 2 of the present invention; In the picture: 1-Wheel frame; 2- Hub motor rotor; 21- Neck; 3- Hub motor stator; 31- Shaft; 4-Planetary gear set; 41-Sun gear; 42-Planet gears; 5-Ratchet mechanism; 51-Ratchet; 52-Pawl; 53-Auxiliary ring; 54-Compression spring; 55-Rebound groove; 6- Gear ring; 7-Clutch assembly; 71-Sliding connecting tube; 72-Fixed tube; 73-Ball bearing; 74-Groove; 8-Protective round shell. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Example 1 Reference Figure 1-6 The diagram shows a hub motor gearbox connected within a wheel frame 1. The hub motor gearbox includes: a hub motor rotor 2, a hub motor stator 3, a planetary gear set 4, a ratchet mechanism 5, a gear ring 6, a clutch assembly 7, and a protective circular shell 8. The outer peripheral sidewall of the hub motor rotor 2 is connected to the inner peripheral sidewall of the wheel frame 1 via the ratchet mechanism 5. The ratchet mechanism 5 includes: a ratchet 51, a pawl 52, an auxiliary ring 53, and a compression spring 54. The ratchet 51 is fixedly connected to the inner peripheral sidewall of the wheel frame 1, and the auxiliary ring 53 is fixedly connected to the outer peripheral sidewall of the hub motor rotor 2. The outer peripheral sidewall of the auxiliary ring 53 has a spring-loaded groove 55. One end of the bottom wall of the spring-loaded groove 55 is hinged to the pawl 52, and the other end of the bottom wall of the spring-loaded groove 55 is press-fitted with one side of the compression spring 54; the other side of the compression spring 54 is press-fitted with the bottom surface of the pawl 52.

[0017] In this embodiment, multiple pawls 52, compression springs 54, and springback grooves 55 are arranged in a circular array on the auxiliary ring 53. Multiple ratchet teeth of the ratchet 51 face the pawl 52, and the inclined sliding surfaces of the ratchet teeth correspond to the inclined sliding surfaces of the pawl 52. When the hub motor rotor 2 rotates forward, the inclined sliding surfaces of the ratchet teeth slide against the inclined sliding surfaces of the pawl 52, thereby allowing the pawl 52 to slide within the ratchet 51. When the hub motor rotor 2 rotates in reverse, the obtuse angle surfaces of the ratchet teeth engage with the obtuse angle surfaces of the pawl 52, thereby allowing the pawl 52 to engage within the ratchet 51.

[0018] The hub motor stator 3 is located inside the hub motor rotor 2. The hub motor stator 3 is provided with a rotating shaft 31, which extends through the hub motor rotor 2 to the outside of the wheel frame 1.

[0019] The planetary gear set 4 includes a sun gear 41 and planet gears 42. A rotating shaft 31 passes through the axis of the sun gear 41, and there is a gap between the rotating shaft 31 and the sun gear 41. The sun gear 41 is driven or disengaged from the hub motor rotor 2 through the clutch assembly 7. The sun gear 41 meshes with the planet gears 42 for transmission.

[0020] In this embodiment, four planetary gears 42 are arranged in a circular array and mesh with the sun gear 41 for transmission.

[0021] The gear ring 6 is fixedly connected to the inner circumferential side wall of the wheel frame 1. The gear ring 6 meshes with four planetary gears 42 for transmission, and the four planetary gears 42 drive the gear ring 6 to rotate.

[0022] In this embodiment, the hub motor rotor 2 is configured in a funnel shape, and the hub motor rotor 2 has a neck 21 on the side facing the planetary gear set 4, and its shaft 31 extends through the neck 21 to the outside of the wheel frame 1.

[0023] In another embodiment, an auxiliary bearing is provided between the rotating shaft 31 and the neck 21.

[0024] The clutch assembly 7 includes a sliding connecting tube 71, a fixed tube 72, and a ball bearing 73. Both the sliding connecting tube 71 and the fixed tube 72 are sleeved on the rotating shaft 31. The outer peripheral sidewall of the sliding connecting tube 71 is provided with a sliding groove 74, and the inner peripheral sidewall of the tube neck 21 is provided with a spherical groove. The ball bearing 73 is rolled in the spherical groove and slides in the sliding groove 74. One end of the fixed tube 72 is fixedly connected to the sun gear 41, and the other end of the fixed tube 72 is engaged or disengaged from the end of the sliding connecting tube 71.

[0025] In this embodiment, the rotation of the neck 21 provides inertia to the sliding connecting tube 71, pushing the sliding connecting tube 71 to slide horizontally on the rotating shaft 31. Both the end of the sliding connecting tube 71 and the end of the fixed tube 72 are provided with clamps, so that the sliding connecting tube 71 can slide close to the fixed tube 72 to engage, or the sliding connecting tube 71 can slide away from the fixed tube 72 to separate.

[0026] In another embodiment, the sliding connecting pipe 71 is an electric telescopic rod. By extending and retracting the electrically controlled sliding connecting pipe 71, the sliding connecting pipe 71 can be engaged or separated from the fixed pipe 72.

[0027] The rotating shaft 31 passes through the axis of the protective circular shell 8, and the two are connected by bearings. The rotating shaft 31 is connected to the axis of the four planetary gears 42 through four connecting rods, and each connecting rod is provided with a bearing between each planetary gear 42.

[0028] A method for speed change of a hub motor includes the following steps: S1. When the vehicle needs to travel at high speed, the hub motor rotor 2 reverses the transmission, the pawl 52 slides in the ratchet 51, the sliding connecting pipe 71 is locked with the fixed pipe 72, driving the sun gear 41 to rotate, and then driving the ring gear 6 to rotate through the planet gear 42, which in turn drives the wheel frame 1 to rotate. S2. When the vehicle needs to travel at low speed, the hub motor rotor 2 rotates forward, the pawl 52 is engaged in the ratchet 51, and the sliding connecting pipe 71 is separated from the fixed pipe 72; the hub motor rotor 2 drives the wheel frame 1 to rotate through the pawl 52 and the ratchet 51.

[0029] According to the planetary gear transmission formula Ns+K Nr-(1+K) Nh=0 Where Ns represents the rotational speed of the sun gear 41; Nr represents the rotational speed of the gear ring at speed 6; Nh represents the planetary gear rotation speed of 42; K represents the gear ratio between gear ring 6 and sun gear 41, i.e., the characteristic parameter of the planetary gear set.

[0030] When driving the sun gear 41, the transmission ratio to the ring gear is Ns = (1 + K). Nh-K Since planetary gear 42 is fixed, its rotational speed Nh is 0. Therefore, the formula simplifies to Ns = -K. Nr. In other words, when the sun gear 41 rotates in the reverse direction, the ring gear rotates in the forward direction, and its transmission ratio is 1:K, which is the gear ratio between the ring gear and the sun gear 41.

[0031] In other words, when the motor rotates in the reverse direction, it can still drive the wheel to rotate in the forward direction, forming a 1:K transmission ratio and producing a torque amplification effect of K times.

[0032] Even during driving, gear shifting will not cause sudden stops or other issues. This is because when the motor switches between forward and reverse, it first stops, then gradually accelerates after reversing its rotation. When shifting from a high gear to a low gear, the ratchet mechanism disengages because the motor's forward rotation speed is lower than the wheel's. The wheel rotates independently, driving the gear ring forward, which in turn drives the sun gear 41 to rotate in the opposite direction. At this time, the sliding connecting pipe 71 and the fixed pipe 72 are disengaged. Therefore, the vehicle coasts when the accelerator is not pressed. When the accelerator is pressed, the sliding connecting pipe 71 moves towards the fixed pipe 72 due to centrifugal force and begins to engage (when the motor's rotation speed is lower than the sun gear 41's rotation speed, the clamp cannot engage properly, and the vehicle continues to coast, gradually decelerating until the sun gear 41's speed is lower than the motor's speed, at which point the clamp engages). Then, the sliding connecting pipe 71 and the fixed pipe 72 engage, causing the wheel to rotate. When the vehicle shifts from a low gear to a high gear, the motor rotates in the opposite direction, and the fixed tube 72 on the sun gear 41 rotates in the opposite direction. The motor either does not rotate or rotates in the opposite direction. Therefore, the fixed tube 72 and the sliding connecting tube 71 will become disengaged, and the two devices will no longer be linked. However, when the motor starts to rotate in the forward direction, the sliding connecting tube 71 begins to move away from the fixed tube 72 under the action of centrifugal force, and no longer interferes with the sun gear 41.

[0033] This invention adds a low-speed gear to an electric bicycle through a simple combination of components, improving the vehicle's climbing performance by increasing the torque of the transmission structure several times over. Climbing ability can be easily achieved without changing the original motor structure and power. This invention maintains the original hub motor directly driving the wheel transmission structure while adding a low-speed, torque-amplifying transmission structure. Its greatest innovation lies in utilizing the motor's ability to easily control forward and reverse rotation, enabling the conversion between conventional drive and reduction gearbox drive, thus greatly simplifying the design of the transmission structure.

[0034] In other words, when the motor rotates forward, it uses the same hub motor direct drive as ordinary electric bicycles. When the motor rotates backward, it is driven by a reduction gear mechanism to amplify the torque and achieve the function of a low speed. At the same time, the structure of this device avoids the impact on the vehicle itself when the motor switches between forward and reverse rotation, and will not cause the vehicle to stop suddenly or vibrate due to the switching of the motor.

[0035] The optimization of the drive system for electric bicycles should include at least two transmission methods: low-speed torque amplification and normal speed, balancing low-speed climbing ability with low-energy consumption for daily driving. Furthermore, since electric bicycles generally use hub motors, using a traditional gearbox structure would require changing the vehicle's drive system, limiting it to shaft drive or chain drive (similar to motorcycle drive structures), significantly increasing the vehicle's complexity and cost.

[0036] This invention solves the problem of insufficient torque in traditional electric bicycles when climbing hills, while avoiding issues such as complex structures, difficult maintenance, high costs, and poor reliability. It provides a completely new structural design approach, enabling a multi-stage transmission structure that is extremely low-cost, highly reliable, and easy to maintain. This significantly improves the road adaptability of electric bicycles.

[0037] 1. Compared with traditional multi-stage gearboxes, it eliminates the need for pushrod structures to achieve drive shaft linkage or disengagement, and eliminates the need for synchronizers, reducing structural complexity and improving the reliability of the structure under complex operating conditions.

[0038] 2. Compared with CVT transmissions, it does not require the use of expensive materials and has a rigid transmission, resulting in higher transmission efficiency.

[0039] 3. No mechanical shifting structure is required, reducing the number of moving parts. No precision parts and precision transmission are needed, resulting in high reliability.

[0040] Example 2 Reference Figure 7 The hub motor gearbox shown is based on embodiment 1. The end of the sliding connecting pipe 71 is provided with an external thread, and the end of the fixed pipe 72 is provided with an internal thread. The sliding connecting pipe 71 and the fixed pipe 72 are connected by thread engagement.

[0041] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A hub motor gearbox, connected within a wheel frame (1), characterized in that, The hub motor gearbox includes: hub motor rotor (2), hub motor stator (3), planetary gear set (4), ratchet mechanism (5), gear ring (6), and clutch assembly (7); The outer peripheral sidewall of the hub motor rotor (2) is connected to the inner peripheral sidewall of the wheel frame (1) through the ratchet mechanism (5); The hub motor stator (3) is disposed inside the hub motor rotor (2); The hub motor stator (3) is provided with a rotating shaft (31), which extends through the hub motor rotor (2) to the outside of the wheel frame (1); The planetary gear set (4) includes a sun gear (41) and planet gears (42); the shaft (31) passes through the axis of the sun gear (41), and there is a gap between the shaft (31) and the sun gear (41); the sun gear (41) is driven or disengaged from the hub motor rotor (2) through the clutch assembly (7); the sun gear (41) meshes with the planet gears (42) for transmission. The gear ring (6) is fixedly connected to the inner circumferential side wall of the wheel frame (1), and the gear ring (6) meshes with the planetary gear (42) for transmission.

2. The hub motor gearbox according to claim 1, characterized in that, The ratchet mechanism (5) includes: a ratchet (51), a pawl (52), an auxiliary ring (53), and a compression spring (54); The ratchet (51) is fixedly connected to the inner peripheral sidewall of the wheel frame (1); The auxiliary ring (53) is fixedly connected to the outer peripheral sidewall of the hub motor rotor (2); The outer peripheral sidewall of the auxiliary ring (53) is provided with a spring-loaded groove (55); One end of the bottom wall of the spring-loaded groove (55) is hinged to the pawl (52), and the other end of the bottom wall of the spring-loaded groove (55) is pressed against one side of the compression spring (54); the other side of the compression spring (54) is pressed against the bottom surface of the pawl (52).

3. The hub motor gearbox according to claim 1, characterized in that, The hub motor rotor (2) is configured in a funnel shape; the hub motor rotor (2) has a neck (21) on the side facing the planetary gear set (4).

4. A hub motor gearbox according to claim 3, characterized in that, The pivot (31) extends through the neck (21) to the outside of the wheel frame (1).

5. A hub motor gearbox according to claim 3, characterized in that, The clutch assembly (7) includes: a sliding connecting tube (71), a fixed tube (72), and a ball bearing (73); The sliding connecting pipe (71) and the fixed pipe (72) are both sleeved on the rotating shaft (31); The outer peripheral sidewall of the sliding connecting pipe (71) is provided with a sliding groove (74); The inner circumferential sidewall of the neck (21) is provided with a spherical groove; The ball (73) is rolled in the spherical groove, and at the same time the ball (73) slides in the groove (74); One end of the fixed tube (72) is fixedly connected to the sun gear (41); The other end of the fixed tube (72) is engaged or disengaged from the end of the sliding connecting tube (71).

6. A method for speed change of a hub motor, characterized in that, The method employs the hub motor gearbox as described in any one of claims 1-5, comprising the following steps: S1. When the vehicle needs to travel at high speed, the hub motor rotor (2) reverses the transmission, the pawl (52) slides in the ratchet (51), the sliding connecting pipe (71) is locked with the fixed pipe (72), the sun gear (41) is driven to rotate, and then the ring gear (6) is driven to rotate through the planet gear (42), which in turn drives the wheel frame (1) to rotate. S2. When the vehicle needs to travel at low speed, the hub motor rotor (2) rotates forward, the pawl (52) is engaged in the ratchet (51), and the sliding connecting pipe (71) is separated from the fixed pipe (72); the hub motor rotor (2) drives the wheel frame (1) to rotate through the pawl (52) and the ratchet (51).

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