Multi-speed-change high-transmission-efficiency electric moped transmission system

Abstract

The invention relates to the technical field of electric moped transmission, in particular to a multi-speed-change high-transmission-efficiency electric moped transmission system which comprises a chain wheel speed change disc, a speed change shell, a rotating shaft, a protective shell, a fan-shaped chain wheel disc, a chain wheel crankset, a supporting arc plate, a tension assembly, a micro motor, a limiting bolt and a contraction assembly. A plurality of groups of fan-shaped chain wheel discs and a chain wheel crankset form a circular chain wheel, a micro motor drives a chain wheel speed change disc to rotate, so that the size of the circular chain wheel formed by the fan-shaped chain wheel discs and the chain wheel crankset is changed, and the transmission ratio of the electric moped is changed through different sizes of a front chain wheel disc and a rear chain wheel disc; multi-stage speed change gears capable of achieving approximate stepless adjustment are formed, the requirement of a rider for the multi-stage gears is met, and the situation of chain falling is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of electric-assisted vehicle transmission, specifically a multi-stage variable-speed and high-transmission-efficiency electric-assisted vehicle transmission system. Background Art

[0002] For the electric-assisted vehicles on the current market, the variable-speed system mainly consists of a front sprocket (located on the crank), a rear sprocket (located on the freewheel), and a chain. The front sprocket disc usually has multiple sprockets of different sizes, and the rear sprocket disc has more sprockets of different sizes, forming a sprocket group; the transmission is usually located at the lower part of the vehicle frame and realizes variable speed by shifting the chain between different sprockets; the rider adjusts the position of the chain through the control device of the transmission (such as a transmission lever), so that it switches from one sprocket to another. In this way, the rider can select different gear ratios, thereby changing the sprocket transmission ratio of the electric-assisted vehicle, making its transmission speed increase but more strenuous to ride, or the transmission speed decrease but more labor-saving to ride.

[0003] The prior art uses multiple groups of sprockets for variable speed. However, for different riders, due to their own habits, strength, and different driving road conditions, the most suitable gear for the rider is different. There is often a too large gap in the transmission ratio between adjacent gears, and the rider's physical feeling cannot reach the most comfortable state; and for the method of variable speed with multiple groups of sprockets, if you want to increase the variable-speed range, you can only do it by increasing the number of sprockets, and the wider the variable-speed range you want to achieve, the more sprockets are used. This not only increases the costs of production, processing, and installation, but also when the chain frequently switches between sprockets, since the variable speed needs to be achieved by shifting the chain, it is easy to occur that the chain is not engaged with the sprocket, resulting in situations such as "chain dropping", which affects the stability of the rider during riding.

[0004] Therefore, a multi-stage variable-speed and high-transmission-efficiency electric-assisted vehicle transmission system is proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a multi-stage variable-speed and high-transmission-efficiency electric-assisted vehicle transmission system, to solve the problems that when the electric-assisted vehicle is variable-speed, due to the gap between the adjusted gears, the rider cannot reach the best physical feeling, and when adjusting the gears, it is easy to produce "chain dropping" by shifting the chain. By forming a circular sprocket with multiple groups of sector sprocket discs and a sprocket tooth disc, and driving the sprocket variable-speed disc to rotate by a micro-motor, thereby changing the size of the circular sprocket formed by the sector sprocket disc and the sprocket tooth disc, and changing the transmission ratio of the electric-assisted vehicle by the different sizes of the front sprocket disc and the rear sprocket disc, a multi-stage variable-speed gear that can be adjusted close to steplessly is formed, meeting the rider's need for multi-stage gears and avoiding the occurrence of "chain dropping" situations.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] Multi-stage variable-speed electric power-assisted vehicle transmission system with high transmission efficiency, including a sprocket variable-speed disc, a transmission housing, a rotating shaft, a protective housing, a sector sprocket disc, a sprocket tooth disc, a support arc plate, a tension assembly, a micro motor, a limit bolt, and a contraction assembly; a planar thread is provided on one side of the sprocket variable-speed disc close to the sector sprocket disc, a fixed circular plate is connected to the inner wall of the transmission housing, and a number of groups of limit shafts are uniformly arranged in a ring on the outer wall of the fixed circular plate. A number of groups of teeth are provided on the side of the sprocket variable-speed disc away from the sector sprocket disc, and two groups of gears are meshed with the teeth; a number of groups of sector sprocket discs are uniformly arranged in a ring on one side of the sprocket variable-speed disc, and a number of groups of sector sprocket discs, sprocket tooth discs, and support arc plates form a circular sprocket; when the micro motor is started to drive one group of gears to rotate, it will drive the sprocket variable-speed disc and the sector sprocket disc to rotate relatively, and the sector sprocket disc will displace along the limit shaft to change the size of the formed circular sprocket; the tension assembly can adaptively adjust the tension of the chain connected to the sprocket tooth disc.

[0008] It can be seen that in the prior art, the variable-speed system of an electric power-assisted vehicle mainly consists of a front sprocket, a rear sprocket, and a chain. The rider adjusts the position of the chain through the control device of the transmission to switch it from one sprocket to another, so as to achieve the effect of adjusting the transmission ratio. In this process, due to the influence of multiple factors, the rider often cannot reach the most comfortable transmission ratio state, and it is easy to have the situation of "chain dropping" when adjusting the gear. By forming a circular sprocket with multiple groups of sector sprocket discs and sprocket tooth discs, and driving the sprocket variable-speed disc to rotate through a micro motor, the size of the circular sprocket formed by the sector sprocket disc and the sprocket tooth disc is changed, forming a multi-stage variable-speed gear that can be adjusted close to steplessly. In this process, there is no need to move the chain to change the meshed sprocket, thus reducing the occurrence of "chain dropping" situation. By the circular sprockets formed by the sector sprocket discs in the front sprocket disc and the rear sprocket disc with sizes inversely proportional to each other, the stability of the sprocket tension during operation is ensured, further reducing the occurrence of "chain dropping" situation.

[0009] Preferably, the contraction assembly includes a contraction plate connected to the sprocket tooth disc, a contraction groove provided on the sector sprocket disc, and an energized spring provided at the contraction groove and connected to the contraction plate; when the energized spring is energized, it will drive the contraction plate and the sprocket tooth disc to move towards the center of the rotating shaft, and the outer end of the sprocket tooth disc will contract into the support arc plate.

[0010] In the above solution, when changing the position of the sector sprocket disc and the size of the circular sprocket formed by it, the gap between each group of sector sprocket discs will change. Since the gap between the chain and the sprocket teeth is a fixed value, the displacement distance of the sector sprocket disc is limited. Through the contraction assembly, the sprocket tooth disc can contract towards the center of the rotating shaft when it is not in the gap position. This process will ensure that at least one complete sprocket tooth disc is meshed with the chain, thus ensuring the operation stability, increasing the displacement range of the sector sprocket disc, and thus increasing the adjustable range of the overall transmission ratio.

[0011] Preferably, the micro motor is connected to the speed change housing, and the drive shaft of the micro motor passes through the speed change housing and is connected to a set of gears; the other set of gears is rotatably connected to the speed change housing, and the limit bolt is threadedly connected thereto. When the sprocket speed change disk and the sector sprocket disk rotate relative to each other, the limit bolt will be driven by the gears to generate a displacement close to or away from the rotating shaft; a limit circular plate is connected to the inner wall of the speed change housing.

[0012] In the above solution, starting the micro motor will drive the sprocket speed change disk to generate relative rotation with the speed change housing and the sector sprocket disk through the gears. During this process, the other set of gears will also be driven to rotate, and the limit bolt will generate a displacement close to or away from the center of the rotating shaft of the speed change housing relative to the speed change housing. The limit bolt will respectively touch the limit circular plate and the protective housing when the sector sprocket disk is at the minimum adjustable position and the maximum adjustable position, preventing the rider from over-adjusting beyond the adjustable range and increasing the running stability during use.

[0013] Preferably, the support arc plate is C-shaped and is arranged on both sides of the sprocket disk.

[0014] In the above solution, the support arc plates are arranged on both sides of the sprocket disk to support the bottom of the chain during riding and generate friction with the chain, further ensuring the stability during use.

[0015] Preferably, an arc surface is provided at the outer end of the sector of the support arc plate.

[0016] In the above solution, the distance from the arc surface to the center of the rotating shaft of the sprocket disk is relatively close on the side close to the sprocket disk. By contacting the chain through the arc surface, it is ensured that the chain and the sprocket disk are always in the same plane during use. By being located at the "concave" surface formed by the two arc surfaces, the chain and the sprocket disk are more closely fitted, and the lateral displacement of the chain is reduced, further reducing the occurrence of the "chain dropping" situation.

[0017] Preferably, the tension assembly includes two sets of sliding grooves provided on the sector sprocket disk, two sets of sliding plates connected to the side of the support arc plate close to the sector sprocket disk, limit posts connected to the outer side of the sliding plates close to the center of the rotating shaft, spring connecting plates provided at the sliding grooves, a V-shaped limit plate slidably connected to the sector sprocket disk, a return spring with two ends respectively connected to the spring connecting plate and the V-shaped limit plate, and unlocking holes symmetrically provided on the V-shaped limit plate; raised blocks are evenly distributed on the planar thread, and the raised blocks are initially arranged not to contact the V-shaped limit plate; when the sprocket speed change disk and the sector sprocket disk rotate relative to each other, the raised blocks squeeze the V-shaped limit plate to generate a displacement in the direction close to the spring connecting plate.

[0018] In the above solution, during the process of adjusting the gear position, the sprocket chainring will reduce its engagement with the chain due to inertia. Especially during the process of the fan-shaped sprocket disc forming a smaller circular sprocket, through the tension assembly, during the process of adjusting the gear position, the raised block will continuously squeeze the V-shaped limiting plate, causing the unlocking hole to displace to the limiting post. Under the influence of inertia during riding, at this time, the limiting post will drive the sliding plate and the supporting arc plate to move away from the center of the rotating shaft. At this time, the outer end of the supporting arc plate will support the chain outward, thereby increasing the tension of the chain during gear adjustment and further reducing the occurrence of "chain dropping".

[0019] Preferably, a damper is provided at the axis of the return spring.

[0020] In the above solution, since the V-shaped limiting plate is continuously squeezed by the raised block, it will move towards the return spring and squeeze the return spring. At this time, through the damper, the process of the V-shaped limiting plate recovering under the elastic force of the return spring will be slowed down, thereby reducing the stress on the V-shaped limiting plate during the adjustment process.

[0021] Preferably, the angle between each group of raised blocks is θ°, and the micro motor is controlled by an encoder so that when rotating, only the sprocket speed change disc rotates by an angle of Nθ°, where N is an integer.

[0022] In the above solution, by setting the encoder, the rotation angle of the micro motor is always kept at Nθ°, thereby ensuring that the V-shaped limiting plate is always between two groups of raised blocks after the gear adjustment is completed.

[0023] Preferably, the tension assembly includes a support shaft, a first connecting shaft connected to the support shaft, a second connecting shaft connected to the end of the first connecting shaft, a tension wheel rotatably connected to the second connecting shaft, and a tension spring with both ends respectively connected to the first connecting shaft and the second connecting shaft.

[0024] In the above solution, by setting the tension assembly, when using a single sprocket speed change disc for adjustment, the tension spring will squeeze the first connecting shaft on both sides, thereby causing the second connecting shaft to rotate clockwise along the first connecting shaft. At this time, the tension wheel engaged with the chain will continuously press down the chain, so that the chain always maintains tension during rotation.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1. The present invention forms a circular sprocket by arranging multiple groups of fan-shaped sprocket discs and sprocket tooth discs, and adjusts the size of the circular sprocket formed by the sprocket speed change disc. By changing the size of the circular sprocket formed by the front sprocket disc and the rear sprocket disc, the transmission ratio between the front sprocket disc and the rear sprocket disc is changed, and the process of adjusting the gear speed change by the multiple groups of sprockets is changed, so that the gear speed change is realized steplessly. Therefore, the rider can adjust to the best physical feeling according to multiple factors such as his own situation and the driving road conditions, thereby increasing the comfort and stability during driving.

[0027] 2. The process of stepless speed change achieved by adjusting the size of the circular sprocket by adjusting the fan-shaped sprocket plate avoids the need to adjust the speed by moving the chain when adjusting the gear, which is easy to cause the problem of "chain dropping". By setting the support arc plate and the tension component, the position supported by the support arc plate will be moved toward the outer side of the rotating shaft through the tension component during the gear adjustment process. The position of the support arc plate will be affected by the centrifugal force during riding. The faster the riding speed, the longer the displacement distance of the support arc plate. In this process, the support arc plate will increase the adaptability of the chain tension, reduce the influence of the circular sprocket on the chain during the process of becoming smaller, increase the stability of the overall operation, and further reduce the occurrence of "chain dropping".

[0028] 3. The present invention forms a circular sprocket by means of a sector-shaped sprocket disc, thereby avoiding the problem of needing to add sprockets when the speed range is to be increased. The more sprockets are used, the further the stability will be reduced when adjusting the speed. By setting a shrinkage component in conjunction with the sprocket tooth plate, the sector-shaped sprocket disc can increase its displacement distance, thereby increasing the adjustable range of the sector-shaped sprocket disc, that is, the speed range, thereby avoiding the need to add sprockets to increase the speed range, and reducing the production, processing and installation costs of multiple sets of sprockets. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the overall structure of the transmission system of the electric power-assisted bicycle with multi-speed transmission and high transmission efficiency;

[0030] Figure 2 It is a schematic diagram of the overall exploded structure of a multi-speed high transmission efficiency electric power-assisted bicycle transmission system;

[0031] Figure 3 It is a schematic diagram of the overall structure of the sprocket of the multi-speed high transmission efficiency electric power-assisted bicycle transmission system;

[0032] Figure 4 A schematic diagram of the internal structure of a sprocket wheel of a multi-speed high-transmission efficiency electric power-assisted bicycle transmission system;

[0033] Figure 5 It is a schematic side view of the overall structure of the sprocket of the multi-speed high transmission efficiency electric power-assisted bicycle transmission system;

[0034] Figure 6 For the Figure 5 magnified schematic view at position A in

[0035] Figure 7 sprocket disc sectional structure schematic view of the multi - stage variable - speed and high - transmission - efficiency electric assist vehicle drive system;

[0036] Figure 8 For the Figure 7 magnified schematic view at position B in

[0037] Figure 9 schematic flow chart of another implementation mode of the multi - stage variable - speed and high - transmission - efficiency electric assist vehicle drive system.

[0038] In the figure: 1, sprocket variable - speed disc; 101, planar thread; 101 - 1, raised block; 102, tooth; 103, gear; 2, variable - speed housing; 201, fixed circular plate; 202, limit shaft; 203, limit circular plate; 3, rotating shaft; 4, protective housing; 5, sector sprocket disc; 6, sprocket tooth disc; 7, support arc plate; 701, arc surface; 8, tension assembly; 801, sliding groove; 802, sliding plate; 803, limit column; 804, spring connecting plate; 805, V - shaped limit plate; 806, return spring; 807, unlocking hole; 808, damper; 809, support shaft; 810, first connecting shaft; 811, second connecting shaft; 812, tension wheel; 813, tension spring; 9, micro - motor; 10, limit bolt; 11, contraction assembly; 1101, contraction plate; 1102, contraction groove; 1103, energized spring. Specific implementation mode

[0039] To make the above - mentioned objects, features and advantages of the present invention more obvious and understandable, the following will make a detailed description of the specific implementation mode of the present invention in conjunction with the accompanying drawings of the specification.

[0040] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can obtain other implementation modes without departing from the connotation of the present invention and without creative labor. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0041] Embodiment 1

[0042] Please refer to Figures 1 to 8 , the present invention provides the following technical solutions:

[0043] Multi-stage variable speed electric assist vehicle transmission system with high transmission efficiency, including a sprocket variable speed disc 1, a transmission housing 2, a rotating shaft 3, a protective housing 4, a sector sprocket disc 5, a sprocket tooth disc 6, a support arc plate 7, a tension assembly 8, a micro motor 9, a limit bolt 10, and a contraction assembly 11; on one side of the sprocket variable speed disc 1 close to the sector sprocket disc 5, there is a planar thread 101, a fixed circular plate 201 connected to the inner wall of the transmission housing 2, several groups of limit shafts 202 arranged annularly and evenly on the outer wall of the fixed circular plate 201, several groups of teeth 102 arranged on the side of the sprocket variable speed disc 1 away from the sector sprocket disc 5, and two groups of gears 103 meshing with the teeth 102; several groups of sector sprocket discs 5 are arranged annularly and evenly on one side of the sprocket variable speed disc 1, and several groups of sector sprocket discs 5, sprocket tooth discs 6, and support arc plates 7 form a circular sprocket; when starting the micro motor 9 to drive one group of gears 103 to rotate, it will drive the sprocket variable speed disc 1 and the sector sprocket disc 5 to produce relative rotation, and the sector sprocket disc 5 will displace along the limit shaft 202 to change the size of the formed circular sprocket; the tension assembly 8 can adaptively adjust the chain tension, form a circular sprocket through multiple groups of sector sprocket discs 5 and sprocket tooth discs 6, drive the sprocket variable speed disc 1 to rotate through the micro motor 9, thereby changing the size of the circular sprocket formed by the sector sprocket disc 5 and the sprocket tooth disc 6, and change the transmission ratio of the electric assist vehicle by the different sizes of the front sprocket disc and the rear sprocket disc of the electric assist vehicle, forming a multi-stage variable speed gear that can be adjusted nearly steplessly, meeting the rider's demand for multi-stage gears and avoiding the occurrence of "chain dropping".

[0044] At the bottom of the sector sprocket disc 5, there are a groove part and a convex part adapted to the planar thread 101. The radial width of the groove part is the same as the radial width of the planar thread 101, and the radial width of the convex part is the same as the radial distance between each annular texture of the planar thread 101. When the micro motor 9 drives the sprocket variable speed disc 1 and the planar thread 101 to rotate through the gear 103, the planar thread 101 will pass through the groove part at the bottom of the sector sprocket disc 5, causing the sector sprocket disc 5 to displace axially along the limit shaft 202; the micro motors 9 on the front sprocket disc and the rear sprocket disc of the electric assist vehicle can be controlled separately. Through a preset encoder, when the two groups of micro motors 9 drive, the sizes of the circular sprockets formed by the sector sprocket disc 5 are inversely proportional, that is, when the size of the circular sprocket formed by one sector sprocket disc 5 becomes larger, the size of the circular sprocket formed by the other sector sprocket disc 5 will become smaller at the same time, and the rotation speed of the micro motor 9 is calculated and preset through the encoder to keep the rotation length of the chain formed when the size of the circular sprocket formed by the sector sprocket disc 5 changes unified.

[0045] As an implementation manner of the present invention, referring to Figure 1 、 Figure 2 、 Figure 3 、 Figure 5 and Figure 6, the contraction assembly 11 includes a contraction plate 1101 connected to the sprocket chainring 6, a contraction groove 1102 provided on the sector sprocket disc 5, and an energized spring 1103 provided at the contraction groove 1102 and connected to the contraction plate 1101; when the energized spring 1103 is energized, it will drive the contraction plate 1101 and the sprocket chainring 6 to move towards the center of the rotating shaft 3, and the outer end of the sprocket chainring 6 will contract into the support arc plate 7; when changing the position of the sector sprocket disc 5 and the size of the circular sprocket formed thereby, the gap between each group of sector sprocket discs 5 will change. Since the gap between the chain and the sprocket is a fixed value, the displacement distance of the sector sprocket disc 5 is limited. The contraction assembly 11 enables the sprocket chainring 6 to contract towards the center of the rotating shaft 3 when it is not at the gap position. This process ensures that at least one complete sprocket chainring 6 meshes with the chain, thereby guaranteeing the operation stability, increasing the displacement range of the sector sprocket disc 5, and thus increasing the adjustable range of the overall transmission ratio.

[0046] As an embodiment of the present invention, referring to Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 , the micro motor 9 is connected to the speed change housing 2, and the drive shaft of the micro motor 9 passes through the speed change housing 2 and is connected to a set of gears 103; another set of gears 103 is rotatably connected to the speed change housing 2, and the limit bolt 10 is threadedly connected thereto. When the sprocket speed change disc 1 and the sector sprocket disc 5 rotate relative to each other, it will drive the limit bolt 10 to displace closer to or farther away from the rotating shaft 3 through the gears 103; a limit circular plate 203 is connected to the inner wall of the speed change housing 2; starting the micro motor 9 will drive the sprocket speed change disc 1 to rotate relative to the speed change housing 2 and the sector sprocket disc 5 through the gears 103. During this process, it will simultaneously drive another set of gears 103 to rotate and drive the limit bolt 10 to displace closer to or farther away from the center of the rotating shaft 3 relative to the speed change housing 2. The limit bolt 10 will respectively abut against the limit circular plate 203 and the protective housing 4 when the sector sprocket disc 5 is at the minimum adjustable position and the maximum adjustable position, preventing the rider from over-adjusting beyond the adjustable range and increasing the operation stability during use.

[0047] As an embodiment of the present invention, referring to Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 , the support arc plate 7 is C-shaped and is provided on both sides of the sprocket chainring 6; the support arc plate 7 is provided on both sides of the sprocket chainring 6 to support the bottom of the chain during riding and generate friction with the chain, further guaranteeing the stability during use.

[0048] As an embodiment of the present invention, referring to Figure 1 , Figure 2 ,Figure 3 , Figure 4 and Figure 5 , an arc-shaped surface 701 is provided at the outer end of the support arc plate 7 in a fan shape; the distance from the arc-shaped surface 701 to the center of the rotating shaft 3 is relatively close on the side close to the sprocket disc 6. The chain contacts with the sprocket disc 6 through the arc-shaped surface 701, ensuring that the chain and the sprocket disc 6 are always in the same plane during use. By being located at the "concave" surface formed by the two arc-shaped surfaces 701, the chain fits more closely with the sprocket disc 6, and the lateral displacement of the chain is reduced, further reducing the occurrence of the "chain dropping" situation.

[0049] As an implementation manner of the present invention, referring to Figure 3 , Figure 4 and Figure 5 Figure 7 and Figure 8 , the tension assembly 8 includes two sets of sliding grooves 801 provided on the fan-shaped sprocket disc 5, two sets of sliding plates 802 connected to the side of the support arc plate 7 close to the fan-shaped sprocket disc 5, a limit post 803 connected to the outer side of the sliding plate 802 close to the center of the rotating shaft 3, a spring connecting plate 804 provided at the sliding groove 801, a V-shaped limit plate 805 slidably connected to the fan-shaped sprocket disc 5, a return spring 806 with two ends respectively connected to the spring connecting plate 804 and the V-shaped limit plate 805, and unlocking holes 807 symmetrically provided on the V-shaped limit plate 805; raised blocks 101-1 are evenly distributed on the planar thread 101, and the raised blocks 101-1 are initially set not to contact the V-shaped limit plate 805; when the sprocket speed-changing disc 1 and the fan-shaped sprocket disc 5 rotate relatively, the raised blocks 101-1 squeeze the V-shaped limit plate 805 to generate a displacement in the direction close to the spring connecting plate 804; during the process of adjusting the gear, at this time, the sprocket disc 6 will reduce the degree of fit with the chain due to the influence of inertia, especially during the process of the fan-shaped sprocket disc 5 forming a smaller circular sprocket. Through the tension assembly 8, during the process of adjusting the gear, the raised blocks 101-1 will continuously squeeze the V-shaped limit plate 805, so that the unlocking holes 807 are displaced to the position of the limit post 803. Under the influence of inertia during riding, at this time, the limit post 803 will drive the sliding plate 802 and the support arc plate 7 to move away from the center of the rotating shaft 3. At this time, the outer end of the support arc plate 7 will support the chain outward, thereby increasing the tension of the chain during gear adjustment and further reducing the occurrence of the "chain dropping" situation.

[0050] As an implementation manner of the present invention, referring to Figure 3 , Figure 4 and Figure 5 Figure 7 and Figure 8, a damper 808 is provided at the axis of the return spring 806; since the V-shaped limit plate 805 is continuously squeezed by the raised block 101-1, it moves towards the return spring 806 and squeezes the return spring 806. At this time, the damper 808 slows down the process of the V-shaped limit plate 805 recovering the elastic force of the return spring 806, thereby reducing the stress on the V-shaped limit plate 805 during the adjustment process.

[0051] As an implementation manner of the present invention, referring to Figure 2 , Figure 3 , Figure 4 , Figure 7 and Figure 8 , the angle between each group of raised blocks 101-1 is θ°. When the micro motor 9 rotates through the encoder control, the sprocket variable speed disc 1 only rotates an angle of Nθ°, where N is an integer; by setting the encoder, the rotation angle of the micro motor 9 is always kept at Nθ°, so as to ensure that the V-shaped limit plate 805 is always located between two groups of raised blocks 101-1 after the gear adjustment is completed.

[0052] Working principle: The micro motor 9 drives the sprocket variable speed disc 1 to rotate to generate a rotation relative to the speed change housing 2, so as to drive the sector sprocket disc 5 to displace along the limit shaft 202 through the plane thread 101, and change the size of the circular sprocket formed by the sector sprocket disc 5 and the sprocket disc 6. By making the sizes of the front sprocket disc and the rear sprocket disc different, the transmission ratio of the electric assisted vehicle is changed. When in use, since the size of the circular sprocket formed by the sector sprocket disc 5 is different during adjustment, and the gap between each group of sector sprocket discs 5 is also different, there will be a problem that the chain cannot be engaged with each sprocket disc 6. Through the contraction component 11, when the chain is in use and cannot be fully engaged with the sprocket disc 6, it can squeeze the sprocket disc 6 to contract towards the axis, so that the adjustment range of the size of the circular sprocket formed by the sector sprocket discs 5 is more free, forming a multi-stage speed change gear that can be adjusted nearly steplessly, meeting the rider's demand for multi-stage gears, and through the tension component 8 during the speed change adjustment process, under the action of centrifugal force, the support arc plate 7 moves downward and away from the axis side, improving the self-tension of the chain to avoid the occurrence of "chain dropping" situation.

[0053] Specifically: By starting the micro-motor 9 to drive the gear 103 to rotate. At this time, the gear 103 drives the sprocket speed change disk 1 to rotate relative to the speed change housing 2 through the tooth 102 meshed with it. At this time, through the sector sprocket disk 5 adapted to the plane thread 101, the sector sprocket disk 5 will displace along the limit shaft 202. The eight groups of sector sprocket disks 5, sprocket tooth disks 6 and support arc plates 7 uniformly arranged in a ring will form a circular sprocket. When the sector sprocket disk 5 displaces along the limit shaft 202, the size of the formed circular sprocket will change. By respectively controlling the rotation of the two groups of micro-motors 9 through a preset control module or an encoder, the size change of the circular sprockets formed on the front sprocket disk and the rear sprocket disk is always inversely proportional. That is, when the micro-motor 9 drives the sector sprocket disk 5 to adjust, if the size of the circular sprocket formed by the sector sprocket disk 5 on the front sprocket disk becomes larger, the size of the circular sprocket formed by the sector sprocket disk 5 on the rear sprocket disk will become smaller. And when the size of the circular sprocket formed by the sector sprocket disk 5 on the front sprocket disk is the minimum value during this change process, the size of the circular sprocket formed by the sector sprocket disk 5 on the rear sprocket disk is the maximum value, and vice versa. And keep the rotation length of the overall formed chain consistent, ensuring the stability of the adjustment process while changing the transmission ratio between the front sprocket disk and the rear sprocket disk, and realizing stepless adjustment of multi-speed gears.

[0054] During use, when the size of the circular sprocket formed by the sector sprocket disk 5 is different during the process of adjusting the speed change, according to the different distances of the sector sprocket disk 5 from the center of the circle, the gaps between each group of sector sprocket disks 5 are also different. When the sprocket tooth disk 6 is not in the gap position through the contraction assembly 11, the connection part of the chain will squeeze the sprocket tooth disk 6 due to its own tension, overcoming the centrifugal force generated by the sprocket tooth disk 6 and the elastic force of the energized spring 1103, so that the sprocket tooth disk 6 contracts towards the center of the rotating shaft 3. During this process, by setting coils at the speed change housing 2 and setting coils inside the sector sprocket disk 5 or on the frame of the electric scooter, through magnetic resonance coupling, when the sprocket tooth disk 6 in the rear sprocket disk is connected to the chain and rotates to a position exceeding the bottom area of the wheel itself, the energized spring 1103 contracts through magnetic wireless power supply, thereby assisting in driving the sprocket tooth disk 6 to contract towards the axis. It should be noted that this process will ensure that the sprocket tooth disk 6 rotating towards the bottom direction of the wheel will mesh with the chain and contract before the next group of sprocket tooth disks 6 meshes with the chain, so that the sprocket tooth disk 6 rotating towards the bottom direction of the wheel can mesh with the chain without being affected by other sprocket tooth disks 6. The sprocket tooth disk 6 in the front sprocket disk contracts when it is connected to the chain and rotates to a position exceeding the top area of the wheel itself, and the rest of the movement modes are the same, ensuring the stability of the operation and increasing the displacement range of the sector sprocket disk 5, thereby increasing the adjustable range of the overall transmission ratio. It should be noted that the energization method of the energized spring 1103 can also be realized by setting an MCU and other methods for fixed-angle auxiliary contraction.

[0055] During the adjustment process, the sprocket speed change disc 1 rotates relative to the speed change housing 2. The planar thread 101 will have a relative displacement with the sector sprocket disc 5, and the raised block 101-1 will continuously press the V-shaped limit plate 805, causing the V-shaped limit plate 805 to move towards the sprocket disc 6. At this time, the V-shaped limit plate 805 will press the return spring 806 and align the unlocking hole 807 with the limit post 803, thus releasing the limit of the V-shaped limit plate 805 on the limit post 803. At this time, under the action of centrifugal force during driving, the limit post 803 will drive the sliding plate 802 and the support arc plate 7 to move away from the axis direction, causing the outer end of the support arc plate 7 to support the chain outward. During the process of the circular sprocket formed by the sprocket disc 6 becoming smaller, due to inertia, the support arc plate 7 will generate a certain displacement outward and increase the chain tension under the action of centrifugal force at different speeds, reducing the occurrence of "chain dropping". It should be noted that to prevent insufficient centrifugal force during rotation, a spring in a compressed state can be set at the sliding groove 801 to push the sliding plate 802 to move outward from the axis.

[0056] Embodiment 2

[0057] In the process of implementation, Embodiment 1 can achieve a larger adjustment range, as well as more precise adjustment and control. However, it requires a higher cost and has higher requirements for intelligent control technology. To meet different implementation situations and implementation requirements, Embodiment 2 provides a more cost-effective and convenient implementation method.

[0058] As an implementation method of the present invention, refer to Figure 9 , the tension assembly 8 includes a support shaft 809, a first connecting shaft 810 connected to the support shaft 809, a second connecting shaft 811 connected to the end of the first connecting shaft 810, a tension wheel 812 rotatably connected to the second connecting shaft 811, and a tension spring 813 with both ends respectively connected to the first connecting shaft 810 and the second connecting shaft 811. Different from the above embodiments, in this implementation method, the sprocket speed change disc 1 is only implemented on the rear sprocket disc of the electric assist vehicle, and the tension assembly 8 is used to maintain the chain tension during the gear shift adjustment process.

[0059] Specifically, when adjusting with a single sprocket speed change disc 1, the process is the same as that of the above embodiment. The micro motor 9 drives the gear 103 to rotate, causing the sector sprocket disc 5 to displace along the limit shaft 202, changing the size of the circular sprocket formed by the sprocket disc 6. The other end of the chain is connected to the conventional front sprocket disc. During the process of adjusting the speed, since the size of the circular sprocket formed by the sprocket disc 6 changes, the length traveled by the chain also changes. Through the tension assembly 8 arranged in this embodiment, during the rotation of the chain, the tension spring 813 will squeeze the first connecting shaft 810 and the second connecting shaft 811 towards both sides, causing the second connecting shaft 811 to rotate clockwise along the first connecting shaft 810. At this time, the tension wheel 812 engaged with the chain will continuously squeeze the chain under the drive of the rotation of the second connecting shaft 811 until the tension of the chain reaches the point of overcoming the elastic force of the tension spring 813, so as to ensure that the chain always maintains tension during rotation. When adjusting the gear, for example, increasing the circular sprocket formed by the sprocket disc 6, at this time, the moving distance of the chain on the sprocket disc 6 will also increase, and the tension of the chain itself will increase. At this time, during the process of increasing the chain tension, the tension wheel 812 will continuously squeeze the second connecting shaft 811 and the tension spring 813, causing the second connecting shaft 811 to rotate counterclockwise relative to the first connecting shaft 810, so as to ensure that the chain always maintains tension during the process of adjusting the gear. It should be noted that the support shaft 809 here can be connected to the protective shell 4 or the frame of the electric scooter.

[0060] The above embodiments are only used to illustrate some examples of the implementable part of the technical solution of the present invention rather than limiting the embodiments. The present invention can be understood in more detail with reference to the embodiments. Those skilled in the art should understand that the technical solution of the present invention can be modified or equivalently replaced without departing from the scope of the technical solution of the present invention, and all of them should be covered by the scope of the claims of the present invention.

Claims

1. A multi-stage variable speed electric power-assisted vehicle transmission system, characterized in that: Including a sprocket speed change disc (1), a speed change housing (2), a rotating shaft (3), a protective housing (4), a sector sprocket disc (5), a sprocket tooth disc (6), a support arc plate (7), a tension assembly (8), a micro motor (9), a limit bolt (10), and a contraction assembly (11); a flat thread (101) is provided on one side of the sprocket speed change disc (1) close to the sector sprocket disc (5), a fixed circular plate (201) is connected to the inner wall of the speed change housing (2), a number of groups of limit shafts (202) are evenly arranged in a ring on the outer wall of the fixed circular plate (201), a number of groups of teeth (102) are provided on one side of the sprocket speed change disc (1) away from the sector sprocket disc (5), and the teeth (102) are meshed with two groups of gears (103); a number of groups of the sector sprocket discs (5) are evenly arranged in a ring on one side of the sprocket speed change disc (1), and a number of groups of the sector sprocket discs (5), the sprocket tooth disc (6), and the support arc plate (7) form a circular sprocket; when the micro motor (9) is started to drive one group of the gears (103) to rotate, it will drive the sprocket speed change disc (1) and the sector sprocket disc (5) to generate relative rotation, and the sector sprocket disc (5) will displace along the limit shafts (202) to change the size of the formed circular sprocket; the tension assembly (8) can adaptively adjust the tension of the chain connected to the sprocket tooth disc (6).

2. The multi-stage variable speed and high transmission efficiency electric power-assisted vehicle transmission system according to claim 1, characterized in that: The contraction assembly (11) includes a contraction plate (1101) connected to the sprocket tooth disc (6), a contraction groove (1102) provided on the sector sprocket disc (5), and an energized spring (1103) provided at the contraction groove (1102) and connected to the contraction plate (1101); when the energized spring (1103) is energized, it will drive the contraction plate (1101) and the sprocket tooth disc (6) to move towards the center of the rotating shaft (3), and the outer end of the sprocket tooth disc (6) will contract into the support arc plate (7).

3. The multi-stage variable speed electric power-assisted vehicle transmission system according to claim 1 or 2, characterized in that: The micro motor (9) is connected to the speed change housing (2), and the drive shaft of the micro motor (9) passes through the speed change housing (2) and is connected to one group of gears (103); the other group of gears (103) is rotatably connected to the speed change housing (2), and the limit bolt (10) is threadedly connected thereto. The relative rotation of the sprocket speed change disc (1) and the sector sprocket disc (5) will drive the limit bolt (10) to generate a displacement close to or away from the rotating shaft (3) through the gears (103); a limit circular plate (203) is connected to the inner wall of the speed change housing (2).

4. The multi-stage variable speed and high transmission efficiency electric power assisted vehicle transmission system according to claim 1, wherein: The support arc plate (7) is C-shaped and is provided on both sides of the sprocket tooth disc (6).

5. The multi-stage variable speed and high transmission efficiency electric power-assisted vehicle transmission system according to claim 1, wherein: An arc surface (701) is provided at the sector outer end of the support arc plate (7).

6. The multi-stage variable speed and high transmission efficiency electric power-assisted vehicle transmission system according to claim 1, wherein: The tension assembly (8) includes two sets of sliding grooves (801) provided on the sector sprocket disc (5), two sets of sliding plates (802) connected to the side of the support arc plate (7) close to the sector sprocket disc (5), limiting columns (803) connected to the outer side of the sliding plates (802) close to the center of the rotating shaft (3), spring connecting plates (804) provided at the sliding grooves (801), a V-shaped limiting plate (805) slidably connected to the sector sprocket disc (5), a return spring (806) with two ends respectively connected to the spring connecting plate (804) and the V-shaped limiting plate (805), and unlocking holes (807) symmetrically provided on the V-shaped limiting plate (805); the end of the limiting column (803) is an arc surface; raised blocks (101-1) are evenly distributed on the planar thread (101), and the raised blocks (101-1) are initially set not to contact the V-shaped limiting plate (805); when the sprocket speed change disc (1) and the sector sprocket disc (5) rotate relatively, the raised blocks (101-1) squeeze the V-shaped limiting plate (805) to generate a displacement in the direction close to the spring connecting plate (804).

7. The multi-stage variable speed and high transmission efficiency electric power-assisted vehicle transmission system according to claim 6, characterized in that: A damper (808) is provided at the axis of the return spring (806).

8. The multi-stage variable-speed high transmission efficiency electric power-assisted vehicle transmission system according to claim 6 or 7, characterized in that: The angle between each group of the raised blocks (101-1) is θ°, and when the micro motor (9) is controlled by an encoder to rotate, the sprocket speed change disc (1) will only rotate an angle of Nθ°, where N is an integer.

9. The multi-stage variable speed and high transmission efficiency electric power-assisted vehicle transmission system according to claim 1, wherein: The tension assembly (8) includes a support shaft (809), a first connecting shaft (810) connected to the support shaft (809), a second connecting shaft (811) connected to the end of the first connecting shaft (810), a tension wheel (812) rotatably connected to the second connecting shaft (811), and a tension spring (813) with two ends respectively connected to the first connecting shaft (810) and the second connecting shaft (811).

Images