Automatic three-speed shifting motor structure for bicycles

Abstract

An automatic three-speed geared motor structure for a bicycle, comprising a central shaft (1), a three-speed geared structure, a planetary gear set (31), a motor housing module (6), and a hub motor module (66) for power output, characterized in that the three-speed geared structure includes a centrifugal clutch shifting mechanism (2) for changing the output mode, as well as a composite planetary ring (7) and a planetary gear set (31) for partial gear shifting; the motor housing module (6) includes a hub motor module (66) for providing electric assistance, wherein the hub motor module (66) is located outside the central shaft (1) within the motor housing module (6).

Description

Technical area

[0001] The present invention relates to the field of shifting mechanisms for bicycles, particularly to a three-speed automatic shifting motor structure for bicycles and a shifting method thereof. State of the art

[0002] In recent years, a global technological revolution has taken place in the field of bicycle electrification, with traditional bicycles being equipped with electrical components such as a motor, battery, electronic controller, torque sensor, and speed sensor. When the rider starts moving, climbs, or encounters greater resistance, the electronic system uses the torque sensor to collect data and send it to the motor controller, which provides the rider with assisted driving power to make the ride more enjoyable.

[0003] This new technology significantly improves bicycle acceleration performance while requiring smarter and faster gear shifting. Traditional manual shifting systems, developed by industry giants Shimano (Japan) and SRAM (USA), are designed for conventional bicycles and require the rider to control the timing of shifts and change gears regularly to maintain a comfortable cadence. However, with the introduction of electric motor assistance, the need to shift gears more frequently has increased significantly, making manual shifting systems a hindrance and unable to meet the demands of this new technology.

[0004] In addition, the separate arrangement of the motor and transmission makes the overall design of the bike more complex, increases the number of components, and offers no advantages in terms of space or cost. External gear systems also require regular maintenance and are prone to damage.

[0005] For these reasons, we developed a three-speed automatic shifting method and structure specifically tailored to the needs of modern electric bicycles. This automatic shifting structure eliminates the disadvantages of manual shifting systems by automatically selecting the appropriate gear based on speed, ensuring a comfortable cadence for the rider. Furthermore, we integrated the motor and automatic transmission into a single unit, solving all of the above-mentioned problems at once.

[0006] The innovation lies in the fact that we have implemented a three-speed transmission using a single planetary gear system. This was achieved with minimal space requirements and a small number of components, thus not only solving the problem of automatic gear shifting but also meeting the requirements of lightweight, low cost, and high efficiency. Invention content

[0007] The aim of this invention is to provide a three-speed automatic shift motor structure for bicycles and its shifting method.

[0008] To achieve this goal, the invention provides the following technical solution: A three-speed automatic shift motor structure for bicycles, comprising a central axle, a three-speed shift structure, a planetary gear and motor housing complex, and a hub motor module for power delivery. The three-speed shift structure includes a centrifugal clutch switching device for switching the output mode and a combined planetary gear and planetary gear for implementing some of the gear shifting.

[0009] The three-speed shift structure also includes a single-stage, a two-stage, and a three-stage transmission to enable a multi-stage overall gear ratio. The centrifugal clutch shift device is used to switch between the single-stage, two-stage, and three-stage transmissions for different transmission types;

[0010] The motor housing contains a hub motor module for providing electric assistance. This hub motor module is located outside the central axis within the motor housing.

[0011] Furthermore, the single-stage and three-stage gearboxes include a planetary gear that transmits the speed of the motor housing. The planetary gear contains a combined planetary frame, with the planetary gear providing a reduction ratio in the single-stage gearbox and a transmission ratio in the three-stage gearbox.

[0012] The three-speed shift structure uses the centrifugal clutch in combination with the planetary gear and the planetary frame to realize different transmission types of the planetary gear;

[0013] The two-stage transmission contains a first centrifugal switching device, the three-stage transmission a second centrifugal switching device, both for centrifugal clutch switching;

[0014] The first centrifugal shifting device works with the combined planetary gear to switch the reduction gear to a normal gear ratio, while the second centrifugal shifting device works with the planetary frame to change the normal gear ratio to an increase gear ratio.

[0015] Furthermore, the combined planetary gear contains a first, second and third gear ring, which are firmly connected to each other and arranged concentrically in the axial space of the gear.

[0016] The tooth profiles of the first, second and third gears have different functions, and the first, second and third gears are connected to each other as a solid structure.

[0017] The tooth profile of the first gear is an involute gear, which represents the outer gear of the planetary gear set, one of the three main elements of the planetary gear set. The second gear is an inner ratchet, and the third gear is an outer ratchet.

[0018] Furthermore, a sun gear is firmly connected to the outside of the central axis, and inside the combined planetary frame a planetary gear set is rotatably mounted, which matches the sun gear;

[0019] The outer part of the planetary gear set meshes with the first ring gear, and the inner part of the planetary gear set meshes with the sun gear. The first ring gear, the planetary gear set on the combined planetary frame, and the sun gear on the central axis together form the planetary transmission structure.

[0020] One end of the combined planetary frame is firmly connected to the fourth gear ring, which serves to support the second centrifugal shift mechanism to enable speed increase. The fourth gear ring is a ratchet ring.

[0021] The single-stage transmission further comprises a first drive plate rotatably connected to the outer side of the central axis. A first drive block is rigidly connected to the outer side of the first drive plate, which in turn is pivotally connected to a first ratchet arm that fits the second gear ring. The inner part of the first ratchet arm is equipped with a force-locking mechanism for reinforcement.

[0022] The first drive block is located on the inside of the second gear ring;

[0023] The force locking mechanism includes a mounting shaft fixedly attached to the top of the first drive plate, on the outside of which a locking spring is rotatably mounted. One end of the locking spring rests tightly against the outer part of the first ratchet arm. The first ratchet arm and the second gear ring form a one-way locking structure, and the locking spring cooperates with the first ratchet arm to generate additional locking force.

[0024] A first pawl spring is mounted between the first drive block and the first pawl arm, which serves to position and fix the pawl arm;

[0025] The second gear ring and the outer pawl arm of the first drive plate form the one-way transmission of the first drive block of the single-stage and two-stage transmission towards the combined planetary gear.

[0026] Furthermore, the first centrifugal shifting mechanism comprises a second drive block attached to the inside of the motor housing. A second drive block is fixedly mounted on the side of the second drive block closest to the combined planetary gear, and the inside of the second drive block is pivotally connected to a second shift pawl designed to engage the third gear ring.

[0027] The side of the second drive block facing the second pawl arm is fixedly connected to a return spring, the opposite end of which is pivotally connected to the second pawl arm;

[0028] The third gear ring connects unilaterally with the second pawl of the second drive block and cooperates with the first centrifugal switching mechanism to achieve unilateral power transmission and interruption.

[0029] On the opposite side of the fourth gear ring, the input shaft of the one-way clutch is attached to the combined planetary frame. This serves to enable one-way power transmission to the second drive block via the one-way clutch. In single-stage transmissions, power is transmitted in one direction, while in two-stage and three-stage transmissions, the clutch is bypassed to interrupt the power transmission of the first stage.

[0030] Furthermore, a centrifugal control mechanism for the second switching pawl is articulated on the side of the second drive block facing the combined planetary gear;

[0031] If the speed of the centrifugal control mechanism does not reach the target value and centrifugal clutch does not occur, the second pawl retracts and does not engage the third gear ring. If the speed of the centrifugal control mechanism reaches the target value and centrifugal clutch occurs, the second pawl disengages and engages the third gear ring.

[0032] Furthermore, the second centrifugal switching mechanism comprises a third switching pawl which is pivotally attached to the side of the first drive block opposite the first switching pawl;

[0033] A second centrifugal spring tension is mounted between the third pawl and the first drive block to fix and position the third pawl; the outer end of the third pawl rests tightly against the opposite side of the locking spring;

[0034] The side of the first drive plate facing the first drive block is equipped with a centrifugal control mechanism to control the third pawl;

[0035] The fourth gear ring and the inner first pawl of the first drive plate together form a one-way transmission mechanism.

[0036] On the opposite side of the fourth gear ring, the input shaft of the one-way clutch is firmly connected to the combined planetary frame. This enables unidirectional power transmission through the one-way clutch to the second drive block. In single-stage transmissions, power is transmitted in one direction, while in two-stage and three-stage transmissions, the overrunning clutch interrupts the power transmission of the first stage.

[0037] Furthermore, when the rotational speed of the three-stage centrifugal control mechanism does not reach the target value and no centrifugal clutch occurs, the third pawl retracts and does not engage with the fourth gear ring, while the first pawl engages with the second gear ring;

[0038] When the speed of the three-stage centrifugal control mechanism reaches the target value and the centrifugal clutch is engaged, the third pawl engages the fourth gear ring, and the first pawl is disengaged or put into the overrunning state so that it disengages from the second gear ring.

[0039] The motor housing contains the hub motor, which serves to accommodate the hub motor module.

[0040] One end of the hub motor is detachably connected to the motor cover, which closes the hub motor housing. The three-speed shifting structure is arranged in a ring around the central axis and is located on the inside of the motor cover. The motor cover and the housing of the three-speed shifting structure are designed as an integrated unit.

[0041] The hub motor module contains the motor's stator and rotor. The stator is rigidly connected to the outside of the central axis, and the hub motor's rotor is mounted either on the inside or outside of the stator.

[0042] The hub motor module also contains a gear box for reducing the motor speed. Furthermore, a brake disc is mounted on the side of the hub motor opposite the motor cover for reducing speed or stopping. Furthermore, a shifting method for the automatic three-speed shifting motor structure for bicycles is proposed. The shifting method is as follows:

[0043] The power is introduced into the combined planetary ring (7) via sprockets, pulleys or gears and output from the combined planetary frame (32) through the planetary gear (31), which enables a reduction to the first gear stage;

[0044] The combined planetary ring (7) cooperates with the first centrifugal shift mechanism (41) to switch the reduction gear to a normal gear ratio, which is the second gear stage;

[0045] The combined planetary ring (7) cooperates with the second centrifugal shift mechanism (51) to increase the normal gear ratio to one gear ratio, which is the third gear stage.

[0046] Furthermore, the exact gear status and the switching process are as follows: S1: First gear: Power is transmitted to the first drive plate via a sprocket, pulley, or gear. The first pawl arm of the first drive block, located on the outside of the first drive plate, remains permanently open under the influence of the power lock spring and the first pawl spring tension, transmitting power to the ratchet teeth of the combined planetary ring. The first and second gear rings are rigidly connected, and the first gear ring transmits power to the combined planetary frame via the planetary gear train, which in turn transmits power to the second drive block via a one-way clutch. The second drive block is rigidly connected to the motor housing, and power is transmitted through the housing. S2: Second gear: Power is transmitted to the first drive plate via a sprocket, pulley, or gear. A centrifugal clutch mechanism is located on the second drive block. When the speed of the second drive block, along with the engine case, reaches the set speed, the second gear centrifugal control mechanism engages. The flyweights open due to centrifugal force and push the clutch disc, unlocking the second ratchet arm. The second ratchet arm opens and engages the third gear ring, transmitting power to the second drive block and the engine case at a 1:1 ratio. In this state, the input and output speeds of the transmission are equal because the power is transmitted directly from the planetary ring to the second drive block, and the planetary gear is not involved in the power transmission.First gear is bypassed by an overrunning clutch between the combined planetary ring and the first drive block, which disables first gear;. S3: Third Gear: Power is transmitted to the first drive plate via a sprocket, pulley, or gear. When the speed of the first drive plate reaches the third gear setting, the second centrifugal shift mechanism engages. The flyweights open due to centrifugal force and push the clutch disc, unlocking the third pawl arm. The third pawl arm opens and engages inward, while the first pawl arm closes due to the failure of the power lock spring. Power is now transmitted through the pawl arm to the fourth ring gear of the combined planetary frame. In this state, power is transmitted through the planetary gear system, with the planetary ring delivering power. Compared to second gear, third gear additionally utilizes the planetary gear system for power transmission, increasing the output speed.

[0047] In summary, the advantageous technical effects of the invention are as follows: 1. Single-stage, two-stage, and three-stage transmissions are used, enabling different gear ratios through different input methods of the planetary gear. The invention is based on the basic principles of the planetary gear system and develops a new transmission structure and method that makes it possible to realize a three-speed automatic transmission using only one planetary gear system and two centrifugal clutch mechanisms. This changes the previous state of the art, which required two planetary gear systems for a three-speed transmission. By reducing the system to a single planetary gear system, not only is the installation space reduced but efficiency is also increased by using fewer gears. Furthermore, cost and weight are significantly reduced, which is a significant advantage given the limited space and the need for lightweight construction in two-wheeled vehicles.This results in a simplification of the structure, a reduction of the installation space, an increase in efficiency and a reduction in costs. 2. A power locking spring is used. During power transmission in first and second gears, the inner pawl is blocked by the clutch disc, and the locking spring is pushed outward, so that the outer pawl remains constantly open due to the spring force. This causes the outer pawl to lose its one-way transmission function and form a fixed connection, enabling stable shifting. 3. A two-stage and a three-stage centrifugal control mechanism are used. When the speed is below the set value, the centrifugal force of the flyweight is smaller than the return force of the spring, and the flyweight closes inward, causing the clutch disc to rotate clockwise. In the deceleration state, the speed of the hub motor housing will be higher than that of the input side due to inertial rotation, that is, the speed of the ratchet ring will be higher than that of the pawl. The ring gear pushes the pawl away, and the clutch disc engages the pawl under the return force of the flyweight, so that the pawl enters the closed state and the power transmission is interrupted. The gear shifts to the previous gear, and the power transmission is stabilized by the overrunning clutch. 4. It uses a hub motor module that eliminates the disadvantages of manual gear shifting. This module adapts perfectly to electrically assisted bicycles and automatically shifts to the appropriate gear for the rider based on speed, ensuring a comfortable cadence. List of figures Fig. : Schematic representation of the spatial structure of the invention; Fig. : Schematic representation of the disassembled structure of the invention; Fig. : Schematic representation of the combined structure of the first and three-stage transmission of the invention; Fig. : Schematic representation of the disassembled structure of the combined planetary ring of the invention; Fig. : Schematic sectional view of the two-stage transmission of the invention; Fig. : Schematic sectional view of the combined structure of the first and three-stage transmission of the invention; Fig. : Schematic sectional view of the invention; Fig. : Schematic representation of the disassembled structure of the motor housing module of the invention.

[0048] Numbers in the figures: 1, central axis; 2, centrifugal clutch shifting mechanism; 3, single-stage transmission; 4, two-stage transmission; 5, three-stage transmission; 6, engine housing component; 7, combined planetary ring; 11, sun gear; 31, planetary gear set; 32, combined planetary frame; 33, planetary gear set; 34, fourth ring gear; 35, first drive plate; 36, first drive block; 37, first shift pawl; 38, power lock mechanism; 39, mounting axis; 310, power lock spring; 311, first pawl spring tension; 41, first centrifugal shifting mechanism; 42, second drive block; 43, second drive block; 44, second shift pawl; 45, return spring; 46, second speed centrifugal control mechanism; 51, second centrifugal shifting mechanism; 52, third pawl; 53, second centrifugal spring tension; 54, centrifugal control mechanism for the third gear; 61, hub motor; 62, motor housing cover; 63, motor stator and rotor; 64, brake disc;65, Gear for motor reduction; 66, Hub motor module; 71, First gear ring; 72, Second gear ring; 73, Third gear ring.; Detailed embodiment

[0049] The invention is further explained below in conjunction with the accompanying drawings. Example 1

[0050] With reference to Fig. and Fig. Described is an automatic three-speed shift motor structure for bicycles, comprising a central axis 1, a three-speed shift structure, and a motor housing component 6 for power transmission. The three-speed shift structure includes a centrifugal clutch shift mechanism 2 for changing the output mode, as well as a combined planetary ring 7 that cooperates with the centrifugal clutch shift mechanism 2 for partial gear shifting. The three-speed shift structure also includes a single-stage transmission 3, a two-stage transmission 4, and a three-stage transmission 5 for implementing multi-stage transmission. The centrifugal clutch shift mechanism 2 serves to switch the various transmission modes of the single-stage transmission 3, the two-stage transmission 4, and the three-stage transmission 5.The first centrifugal shift mechanism 41 cooperates with the combined planetary ring 7 to change the reduction gear ratio to a normal gear ratio, and the second centrifugal shift mechanism 51 cooperates with the combined planetary frame 32 to increase the normal gear ratio to a gear ratio.

[0051] When the hub motor's speed reaches the target speed, the centrifugal force of the flyweights exceeds the spring force, opening the flyweights and driving the clutch disc counterclockwise. This disengages the locking function of the clutch disc pawls, and the second pawl opens and engages the ratchet teeth of the third ring gear 73 of the combined planetary ring. This allows power to be transmitted from the second drive block to the third ring gear 73 of the combined planetary ring. The transmission speed is now higher than the speed originally achieved by the planetary gear set in first gear, since the power transmission between the original planetary frame and the second drive block was achieved via a one-way clutch.When the speed of the second drive block exceeds that of the planetary frame, the overrunning clutch engages, first gear is disengaged, and power is transmitted in second gear. The output and input speeds are the same, and the planetary gear train is not involved in power transmission. The single-stage transmission 3 and the three-stage transmission 5 contain a planetary gear train 31 for transmission in the motor housing 6. The planetary gear train 31 includes the combined planetary frame 32. In the single-stage transmission 3, the planetary gear train 31 functions as a reduction gear, while in the three-stage transmission 5, it functions as a transmission gear train. The three-speed transmission structure uses the centrifugal clutch switching mechanism 2 in combination with the combined planetary ring 7 and the combined planetary frame 32 to realize various transmission modes of the planetary gear train 31.The two-stage transmission 4 contains the first centrifugal shift mechanism 41, and the three-stage transmission 5 contains the second centrifugal shift mechanism 51. The first centrifugal shift mechanism 41 cooperates with the combined planetary frame 7 to change the reduction gear ratio to a normal gear ratio, and the second centrifugal shift mechanism 51 cooperates with the combined planetary frame 32 to increase the normal gear ratio to a higher gear ratio. When the speed of the centrifugal mechanism reaches the target value in third gear, the flyweights open, and the clutch disc rotates counterclockwise. The third-gear pawls disengage from the clutch disc and open inward to engage the ratchet teeth of the inner planetary frame.The first drive block now transmits power directly to the planetary frame, and the planetary reduction mechanism is switched to a fixed sun gear configuration, with the planetary frame providing the input and the third ring gear 73 providing the output. The output speed is higher than the input speed. The gear ratio can be adjusted by varying gear parameters. The power is output through the planetary ring and connected to the second gear power transmission line to transmit the power to the hub motor housing. Because the third pawl is open, the first pawl locking spring rotates inward, and the force on the first pawl disappears, activating the overrunning clutch. The second gear power transmission switches from the first pawl to the third pawl, activating the third gear.

[0052] In relation to Fig. The combined planetary gear 7 includes the fixed first gear 71, the second gear 72, and the third gear 73. These three gears are arranged concentrically in the axial space of the gear train. The tooth profiles of the first, second, and third gears have different functions, and all three are fixedly connected to each other. The tooth profile of the first gear 71 is an involute gear and forms the outer gear of the planetary gear 31, one of the three main elements of the planetary gear train. The second gear 72 is an inner ratchet gear, while the third gear 73 is an outer ratchet gear. The number of teeth of the combined planetary gear 7 can be adjusted depending on the circumstances to regulate the overall speed appropriately during production.

[0053] In relation to Fig. The sun gear 11 is fixedly connected to the outside of the central axis 1, while inside the combined planetary frame 32, a planetary gear set 33 is rotatably connected to the sun gear 11. The outer part of the planetary gear set 33 meshes with the first ring gear 71, while the inner part is connected to the sun gear 11. The first ring gear 71, the planetary gear set 33 on the combined planetary frame 32, and the sun gear 11 on the central axis 1 together form the planetary gear transmission structure. Fixedly connected to one end of the combined planetary frame 32 is the fourth ring gear 34, which cooperates with the second centrifugal shift mechanism 51 to enable an increase in the transmission ratio. The fourth ring gear 34 is a ratchet gear. The single-stage transmission 3 includes a first drive plate 35 rotatably attached to the outside of the central axis 1.A first drive block 36 is fixedly connected to the outside of the first drive plate 35. The outer part of the drive block 36 is pivotally connected to a first pawl arm 37, which cooperates with the second gear ring 72. On the inside of the pawl arm 37 is a force locking mechanism 38 to reinforce the structure. The first drive block 36 is located on the inside of the second gear ring 72. The force locking mechanism 38 includes a mounting shaft 39 attached to the upper end of the first drive plate 35. A force locking spring 310 is rotatably mounted on the outside of the mounting shaft 39. One end of the locking spring 310 lies tightly against the outside of the first pawl arm 37. The pawl arm 37 cooperates with the second gear ring 72 to form a one-way locking structure.The locking spring 310 cooperates with the first pawl arm 37 to form an additional locking structure. A first pawl spring tension 311 is mounted between the first drive block 36 and the pawl arm 37, which serves to fix and position the pawl arm. The second gear ring 72 and the outer pawl arm 37 of the first drive plate 35 form the one-way power transmission from the first drive block of the single-stage transmission 3 and the two-stage transmission 4 to the combined planetary ring 7. The power locking mechanism 38 preferably uses a locking spring 310, but this is not the only possible locking structure. This design uses the optimal structure. The pawl arm 37 and the second gear ring 72 cooperate to form a one-way locking structure, and the locking spring 310 and the pawl arm 37 cooperate to form an additional reinforcement structure.

[0054] In relation to Fig. The first centrifugal switching mechanism 41 comprises a second drive block 42, which is fastened to the inside of the motor housing component 6. The side of the second drive block 42 facing the combined planetary ring 7 is fixedly connected to a second drive block 43. The inside of the second drive block 43 is pivotally connected to a second switching pawl 44, which engages with the third gear ring 73. On the side of the second drive block 43 facing the second switching pawl arm 44, a return spring 45 is fastened, which is connected on the opposite side to the second switching pawl 44. The third gear ring 73 is connected on one side to the second switching pawl 44 on the second drive block 42 and cooperates with the first centrifugal switching mechanism 41 to realize or interrupt the one-sided power transmission.On the opposite side of the fourth gear ring 34, an input shaft of the one-way clutch is attached to the combined planetary frame 32. This enables a one-way clutch to transmit power to the second drive block 42. In the single-stage transmission 3, the power is transmitted in one direction, while in the two-stage transmission 4 and the three-stage transmission 5, the overrunning clutch interrupts the first-gear power transmission.

[0055] In relation to Fig. A two-stage centrifugal control mechanism 46 is pivotally mounted on the side of the second drive block 42 facing the combined planetary ring 7, which controls the second switching pawl 44. If the speed of the second centrifugal control mechanism 46 does not reach the target value and no centrifugal clutch is engaged, the second switching pawl 44 retracts and does not engage the third gear ring 73. If the speed reaches the target value and the centrifugal clutch is engaged, the second switching pawl 44 pops out and engages the third gear ring 73. The second centrifugal switching mechanism 51 includes a third switching pawl 52 pivotally mounted on the side of the first drive block 36 facing away from the first switching pawl arm 37. Between the third switching pawl 52 and the first drive block 36 there is a second centrifugal spring tension 53, which serves to fix and position the third switching pawl 52.The outer side of the third pawl 52 rests tightly against the other side of the power lock spring 310. The side of the first drive plate 35 facing the first drive block 36 is equipped with a three-stage centrifugal control mechanism 54 that controls the third pawl 52. The fourth ring gear 34 and the inner first pawl arm 37 of the first drive plate 35 together form a one-way power transmission mechanism. On the opposite side of the fourth ring gear 34, the input shaft of the one-way clutch is attached to the combined planetary frame 32, enabling one-way power transmission to the second drive block 42. In the single-stage transmission 3, the power is transmitted in one direction, while in the two-stage transmission 4 and the three-stage transmission 5, the overrunning clutch interrupts the power transmission of the first gear.When the speed of the three-stage centrifugal control mechanism 54 does not reach the target value and no centrifugal clutch is engaged, the third pawl 52 retracts and does not engage the fourth ring gear 34, while the first pawl arm 37 engages the second ring gear 72. When the speed of the three-stage centrifugal control mechanism 54 reaches the target value and the centrifugal clutch is activated, the third pawl 52 pops out and engages the fourth ring gear 34, while the first pawl arm 37 retracts and either disengages from the second ring gear 72 or enters the overrunning state. When the centrifugal force of the flyweights is less than the spring force, the flyweights retract inward and drive the clutch disc clockwise.During deceleration, the speed of the hub motor housing will be higher than that of the input side due to inertia, meaning the speed of the ratchet ring will be higher than that of the pawl, causing the ring gear to push the pawl away. At this moment, the clutch disc engages the pawl under the restoring force of the flyweights, causing the pawl to close, interrupting power transmission, and shifting to the previous gear. The overrunning clutch, which was activated by the previous gear, remains engaged, and the outer side of the third shift pawl 52 remains tightly against the other side of the power lock spring 310.

[0056] In relation to Fig.The motor housing component 6 contains a hub motor module 66, which serves to provide electrical assistance. The hub motor module 66 is located on the outside of the central axis 1 within the motor housing component 6. The motor housing component 6 also contains a hub motor housing 61, which serves to accommodate and arrange the hub motor module 66. One end of the hub motor housing 61 is removably connected to a hub motor cover 62, which closes the hub motor housing 61. The three-speed shifting structure is arranged in a ring around the central axis 1 and is located on the inside of the hub motor cover 62. The hub motor cover 62 and the housing of the three-speed shifting structure are designed as an integrated unit. The hub motor module 66 contains a stator and rotor 63 of the motor, with the stator being fixedly connected to the outside of the central axis 1. The rotor of the motor 63 is arranged either on the inside or outside of the stator.The hub motor module 66 also contains a gearbox 65 for reducing the motor speed. On the side of the hub motor housing 61 facing away from the hub motor cover 62 is a brake disc 64, which serves to reduce speed or stop. There are several possible placement options for the stator and rotor of the motor 63. The design described here is for clarity only, and the exact arrangement can be adapted depending on the circumstances.

[0057] Operating principle: The power is introduced into the first drive plate 35 via sprockets, pulleys, or gears. The first drive block 36 on the outside of the first drive plate 35 remains constantly open under the influence of the power lock spring 310 and the first pawl spring tension 311 and transmits the power to the ratchet teeth of the combined planetary ring 7. The first ring gear 71 and the second ring gear 72 are fixedly connected to each other. The first ring gear 71 transmits the power to the planetary frame via the planetary gear set 33, which then transmits the power to the second drive block 42 via a one-way clutch. The second drive block 42 is fixedly connected to the motor housing component 6, and the power is transmitted and output to the motor housing component 6 by the two-stage centrifugal control mechanism 46.When power is transmitted to the first drive plate 35 via sprockets, pulleys, or gears, a centrifugal clutch mechanism is located on the second drive block 42. When the speed of the second drive block 42, together with the motor housing component 6, reaches the setpoint, the two-stage centrifugal control mechanism 46 engages, and the locking function of the clutch disc is released. The second pawl 44 opens and engages the third gear 73, so that power is transmitted to the second drive block 42 and the motor housing component 6 in a 1:1 ratio. In this state, the output and input speeds of the transmission are equal.

[0058] The planetary gear train does not participate in power transmission, as first gear is bypassed by overrunning the one-way clutch between the combined planetary ring 7 and the first drive block 36, and first gear power transmission is deactivated. Power is transmitted to the first drive plate 35 via sprockets, pulleys, or gears. When the rotational speed of the first drive plate 35 reaches the speed designated for third gear, the third pawl 52 of the second centrifugal shift mechanism 51 is thrown out and opens inward. Simultaneously, the outer pawl of the first pawl arm 37 closes because the power locking spring 310 is no longer effective. At this moment, the pawl engages the second ring gear 72. The ratchet teeth and the planetary frame form a single unit. Power is transmitted to the planetary frame and output via the planetary ring.In second gear, the planetary ring is transmitted directly to the housing, but in third gear the power is additionally transmitted through the planetary gear, increasing the speed through the gear ratio of the planetary gear.

[0059] The examples described in this specific embodiment represent preferred embodiments of the invention and do not limit the scope of the invention. Therefore, all equivalent modifications resulting from the structure, form, or principle of this invention are within the scope of the invention. Summary

[0060] The present invention discloses an automatic three-speed shift motor structure for bicycles and its shifting method. It relates to the field of bicycle shifting technology and aims to solve the problem that existing bicycle shift structures do not allow three-speed shifting in small spaces, thereby increasing manufacturing costs. The essential features of the technical concept include a central axis, a three-speed shift structure, and a motor housing component for power transmission. The three-speed shift structure includes a centrifugal clutch shifting mechanism for changing the output mode and a combined planetary ring for assisting the centrifugal shift mechanism in partial gear shifting. The three-speed shift structure further includes a single-stage, a two-stage, and a three-stage transmission for realizing multi-stage transmission.The centrifugal clutch shift mechanism enables switching between the different transmission modes of the single-, two-, and three-stage transmissions. This design simplifies the structure, reduces installation space, increases transmission efficiency, and reduces costs.

Claims

[1] An automatic three-speed geared motor structure for a bicycle, comprising a central axis (1), a three-speed gear structure, a planetary gear (31) and a motor housing module (6) and a hub motor module (66) for power output, characterized by in that the three-speed transmission structure includes a centrifugal clutch switching mechanism (2) for changing the output mode, as well as a compound planetary ring (7) and a planetary gear set (31) for partial gear shifting; the motor housing module (6) includes a hub motor module (66) for providing electrical assistance, the hub motor module (66) being located outside the central axis (1) within the motor housing module (6). [2] Automatic three-speed gear motor structure for a bicycle according to claim 1, characterized bythat the three-speed transmission structure additionally comprises a single-stage transmission (3), a two-stage transmission (4) and a three-stage transmission (5) for realizing a multi-stage overall transmission ratio, wherein the centrifugal clutch switching mechanism (2) serves to switch between the transmissions (3), (4) and (5) for different transmission types. [3] Automatic three-speed gear motor structure for a bicycle according to claim 2, characterized by in that the single-stage transmission (3) and the three-stage transmission (5) contain a planetary gear (31) for speed transmission in the motor housing module (6), wherein the planetary gear (31) comprises a composite planetary frame (32). The planetary gear (31) operates as a reduction gear in the first transmission stage (3) and as a transmission gear in the third transmission stage (5). [4] Automatic three-speed gear motor structure for a bicycle according to claim 3, characterized bythat the three-speed transmission structure enables different transmission modes of the planetary gear (31) through the centrifugal clutch switching mechanism (2) in conjunction with the composite planetary ring (7) and the composite planetary frame (32); The two-stage transmission (4) includes a first centrifugal switching mechanism (41) for clutch switching, while the three-stage transmission (5) includes a second centrifugal switching mechanism (51) for clutch switching; The first centrifugal switching mechanism (41) cooperates with the compound planetary ring (7) to switch the reduction gear ratio to a normal gear ratio, while the second centrifugal switching mechanism (51) cooperates with the compound planetary frame (32) to switch the normal gear ratio to a transmission gear ratio. [5] Automatic three-speed gear motor structure for a bicycle according to claim 4, characterized byin that the composite planetary ring (7) comprises a first gear ring (71), a second gear ring (72), and a third gear ring (73) that are interconnected. These three gear rings are arranged concentrically in the axial space of the transmission. [6] Automatic three-speed gear motor structure for a bicycle according to claim 5, characterized by that the central axis (1) is firmly connected to a sun gear (11) on the outside. The composite planetary frame (32) is rotatably connected to a planetary gear set (33) adapted to the sun gear (11); The outer portion of the planetary gear set (33) meshes with the first ring gear (71), while the inner portion meshes with the sun gear (11). The first ring gear (71) forms a planetary gear transmission structure with the planetary gear set (33) mounted on the composite planetary frame (32) and the sun gear (11) mounted on the central axis (1). [7] Automatic three-speed gear motor structure for a bicycle according to claim 5, characterized by in that the single-stage transmission (3) comprises a first drive plate (35) rotatably connected to the central axis (1). The outer region of the first drive plate (35) is fixedly connected to a first drive block (36). The outer region of the first drive block (36) is pivotally connected to a first drive pawl (37) adapted to the second gear ring (72). On the inner side of the first drive pawl (37) is a reinforcing means in the form of a force-locking mechanism (38). [8] Automatic three-speed gear motor structure for a bicycle according to claim 7, characterized by that the first drive block (36) is located on the inside of the second gear ring (72); The power locking mechanism (38) comprises a mounting shaft (39) attached to the upper end of the first drive plate (35). A power locking spring (310) is rotatably mounted around the outer side of the mounting shaft (39). One end of the power locking spring (310) bears against the outer side of the first drive pawl (37); The first drive pawl (37) together with the second gear ring (72) forms a one-sided transmission locking structure, while the force locking spring (310) and the first drive pawl (37) together form a tension force locking structure; Between the first drive block (36) and the first drive pawl (37) there is a first pawl tension spring (311), which serves to firmly position the first drive pawl (37); the second gear ring (72) and the outer first drive pawl (37) on the first drive plate (35) form a one-sided transmission effect from the single-stage gear (3) and the two-stage gear (4) to the composite planetary ring (7). [9] Automatic three-speed gear motor structure for a bicycle according to claim 5, characterized byin that the first centrifugal switching mechanism (41) comprises a second drive mount (42) which is fastened to the inside of the motor housing module (6). On the side of the second drive mount (42) facing the composite planetary gearing (7), a second drive block (43) is fixedly attached, which is pivotally connected on the inside to a second drive pawl (44) which engages the third gear ring (73). [10] Automatic three-speed gear motor structure for a bicycle according to claim 9, characterized by that a return spring (45) is attached to the side of the second drive block (43) facing the second drive pawl (44). The distal end of the return spring (45) is pivotally connected to the second drive pawl (44); The third gear ring (73) is connected on one side to the second drive pawl (44) on the second drive bracket (42), wherein the first centrifugal switching mechanism (41) enables the transmission and interruption of the one-sided power transmission. [11] Automatic three-speed gear motor structure for a bicycle according to claim 7, characterized by that the composite planetary frame (32) is fixedly connected to an input shaft of a one-way clutch on the opposite side of the fourth gear ring (34). This serves to realize a one-way power transmission via the one-way clutch and the second drive mount (42), wherein a one-way power transmission takes place in the single-stage transmission (3), and in the two-stage transmission (4) and the three-stage transmission (5), the one-way clutch disconnects the drive of the first stage; On the side of the second drive bracket (42) facing the composite planetary gearing (7), a two-stage centrifugal control mechanism (46) is pivotally mounted, which controls the second drive pawl (44); If the speed of the two-stage centrifugal control mechanism (46) does not reach the set value and no centrifugal clutch is generated, the second drive pawl (44) retracts and does not engage the third gear ring (73). If the speed of the two-stage centrifugal control mechanism (46) reaches the set value and the centrifugal clutch is activated, the second drive pawl (44) springs open and engages the third gear ring (73). [12] Automatic three-speed gear motor structure for a bicycle according to claim 7, characterized bythat the second centrifugal switching mechanism (51) comprises a third drive pawl (52) which is pivotally attached to the side of the first drive block (36) facing away from the first drive pawl (37); Between the third drive pawl (52) and the first drive block (36) there is a second centrifugal spring (53) which serves to hold the third drive pawl (52) in position; the outer side of the third drive pawl (52) bears against the opposite end of the power locking spring (310); The side of the first drive plate (35) facing the first drive block (36) is provided with a third centrifugal control mechanism (54) for controlling the third drive pawl (52). [13] Automatic three-speed gear motor structure for a bicycle according to claim 12, characterized bythat, when the rotational speed of the third centrifugal control mechanism (54) does not reach the set point and no centrifugal clutch is formed, the third drive pawl (52) remains retracted and does not engage the fourth gear ring (34) while the first drive pawl (37) engages the second gear ring (72); When the speed of the third centrifugal control mechanism (54) reaches the set point and a centrifugal clutch is activated, the third drive pawl (52) pops out and engages the fourth ring gear (34), while the first drive pawl (37) retracts and separates from the second ring gear (72) or enters an overrun mode. [14] Automatic three-speed gear motor structure for a bicycle according to claim 13, characterized byin that the motor housing module (6) comprises a hub motor housing (61) for accommodating the hub motor module (66), wherein one side of the hub motor housing (61) is removably connected to a hub motor end cover (62) that closes the hub motor housing (61). The three-speed transmission structure is arranged in a ring around the central axis (1) and is located on the inside of the hub motor end cover (62). The hub motor end cover (62) and the housing of the three-speed transmission structure are designed as a single unit; The hub motor module (66) comprises a stator and a rotor (63), wherein the stator of the hub motor (63) is fixedly connected to the outside of the central axis (1). The rotor of the hub motor (63) is located either on the inside or the outside of the stator. The hub motor module (66) also comprises a gear set (65) for reducing the motor speed. [15] Automatic three-speed gear motor structure for a bicycle according to claim 14, characterized by that a brake disc (64) is mounted on the side of the hub motor housing (61) facing away from the hub motor end cover (62), which brake disc serves to control the overall deceleration or to stop. [16] Automatic three-speed geared motor structure for a bicycle according to any one of claims 1 to 15, characterized by that it is designed to carry out the switching process as follows: The power is transmitted to the compound planetary ring (7) via a sprocket, a pulley or a gear and output through the planetary gear (31) via the planetary frame (32) to achieve a reduction transmission serving as a first gear; The compound planetary ring (7) switches from a reduction transmission to a normal transmission serving as a second gear by means of the first centrifugal switching mechanism (41); The compound planetary ring (7) switches from the normal transmission to a gear transmission serving as a third gear by means of the second centrifugal switching mechanism (51). [17] Automatic three-speed geared motor structure for a bicycle according to claim 16, characterized by that it is further designed to carry out the switching process in detail as follows: S1: First gear: Power is transmitted to the first drive plate (35) via a sprocket, pulley, or gear. The outer first drive pawl (37) of the first drive block (36) on the first drive plate (35) remains permanently open to the outside due to the action of the power locking spring (310) and the first pawl tension spring (311), transmitting power to the locking teeth of the composite planetary ring (7). The first gear ring (71) and the second gear ring (72) are firmly connected to each other, and The first gear ring (71) transmits the power to the composite planetary frame (32) via the planetary gear set (33). The planetary frame (32) transmits the power to the second drive seat (42) via a single-stage overrunning clutch, which is rigidly connected to the motor housing module (6), thereby outputting the power from the housing. S2: Second gear: Power is transmitted to the first drive plate (35) via a sprocket, pulley, or gear, and the second drive seat (42) is equipped with a centrifugal clutch mechanism. When the speed of the second drive seat (42) and the motor housing module (6) reaches the set value, the second centrifugal control mechanism (46) engages. Centrifugal force opens the centrifugal pads and drives the clutch disc, releasing the lock of the second drive pawl (44). The second drive pawl (44) is released and engages the third ring gear (73). The 1:1 transmission transmits power to the second drive seat (42) and the motor housing module (6).At this time, the transmission output speed is equal to the input speed, since the power is transmitted directly to the second drive seat (42) via the planetary ring, and the planetary mechanism is not involved in the power transmission. First gear is bypassed by a freewheel transmission mechanism between the composite planetary ring (7) and the first drive block (36), thereby disabling first gear. S3: Third gear: Power is transmitted to the first drive plate (35) via a sprocket, pulley, or gear. When the speed of the first drive plate (35) reaches the speed specified for third gear, the second centrifugal shift mechanism (51) opens the centrifugal pads through centrifugal force and disengages the clutch of the third drive pawl (52). The third drive pawl (52) is released and swings inward, while the first drive pawl (37) is deactivated by the action of the power locking spring (310), and the outer pawls close. Power is now transmitted via the pawls to the fourth ring gear (34) on the composite planetary frame (32). Power is input through the planetary frame and output through the planetary ring.Compared to second gear, where the planetary ring is transmitted directly to the engine housing module (6), in third gear the power is additionally transmitted via the planetary mechanism, which increases the output speed.

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