Fixing mechanism, bottom bracket transmission and mid-drive motor

Abstract

A fixing mechanism (3), a bottom bracket derailleur and a mid-drive motor. The fixing mechanism (3) uses a ratchet and pawl mechanism, and comprises control pawls, control cams and ratchet slots. During the rotation of the control cams, the control cams drive the control pawls to swing, thereby driving the control pawls to be locked with or released from the ratchet slots, which are provided on gear rings. When the control pawls engage with the ratchet slots, the gear rings are hindered from rotating unidirectionally, thereby achieving the function of fixing the gear rings. The fixing mechanism (3) has the advantages of a small size, light weight, a simple structure, convenient control, convenient assembly, easy maintenance, etc.

Description

A fixing mechanism, a central shaft transmission and a central motor

[0001] This application claims priority to the Chinese patent application filed with the Patent Office of China on December 12, 2023, with application number 202311702052.9, and invention name “A fixing mechanism, a mid-shaft transmission and a mid-mounted motor”, and the Chinese patent application filed with the Patent Office of China on September 9, 2023, with application number 202322445929.2, and invention name “A mid-shaft transmission and a mid-mounted motor”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention belongs to the technical field of transmissions, and in particular relates to a fixing mechanism, a mid-shaft transmission and a mid-mounted motor. Background Art

[0003] Ebike is short for Electric Bike, also known as an electric-assisted bicycle. It is a bicycle that uses batteries and electric motors to provide auxiliary power. Unlike traditional bicycles, Ebike uses batteries and electric motors to provide auxiliary power, making riding easier and more convenient.

[0004] Chinese patent document CN110997472A discloses a drive assembly and a vehicle, which use driving elements arranged radially and / or axially outside the respectively coupled sun gears, and the corresponding driving elements can be controllably braked, stopped and / or released through controllable friction locking with brake elements, thereby realizing a gear shifting function. However, the brake element of this patent document is hydraulically driven and the driving element uses a brake disc, which results in the overall volume of the drive assembly being too large and inconvenient to control gear shifting.

[0005] Therefore, the existing technology needs to be improved and developed.

[0006] Summary of the Invention

[0007] The purpose of this application is to provide a fixing mechanism, a mid-shaft transmission and a mid-mounted motor, which have the advantages of small size, light weight, simple structure, convenient control, easy assembly and easy maintenance.

[0008] In order to solve the above technical problems, the present application provides a fixing mechanism, including a control pawl, a control cam and a ratchet groove, wherein the ratchet groove is formed on the gear ring of the transmission mechanism, the control pawl is connected to the control cam, and the control cam rotates to engage or disengage the control pawl with the ratchet groove.

[0009] Furthermore, one end of the control pawl is slidingly connected to the control cam, and the control cam is provided with a control groove. When one end of the control pawl slides into the control groove, the other end of the control pawl engages with the ratchet groove.

[0010] Furthermore, the control pawl rotates around the fulcrum to form a labor-saving lever or a labor-intensive lever.

[0011] Furthermore, it also includes a shell, the shell is equipped with a rotating shaft, and the control pawl is rotatably connected to the rotating shaft.

[0012] Furthermore, a plurality of control cams are provided, and the plurality of control cams are provided on the camshaft.

[0013] Furthermore, the camshaft is driven by an electric shift mechanism or a manual shift mechanism.

[0014] Furthermore, the electric shift mechanism includes a driving device, an output end of which is connected to a first reduction mechanism and a camshaft, and a buffer device and a gear feedback device are further provided between the driving device and the camshaft.

[0015] Furthermore, the manual shift mechanism includes a fixed disk and a rotating disk capable of rotating relative to the fixed disk, the rotating disk is provided with a wire groove, the fixed disk is fixedly installed with a wire tube, the control wire passes through the wire tube, is wrapped around the wire groove of the rotating disk and is fixed to the rotating disk.

[0016] The present application also provides a mid-axle transmission, characterized in that it includes the above-mentioned fixing mechanism, one end of the fixing mechanism is connected to the vehicle frame, and the other end of the fixing mechanism is connected to a portion of the transmission mechanism, and further includes:

[0017] a middle shaft, the middle shaft being rotatably supported on the frame and through which torque is input;

[0018] a transmission mechanism connected to the central shaft, the transmission mechanism having at least one transmission ratio;

[0019] A one-way clutch assembly, one end of which is connected to the vehicle frame and the other end is connected to another part of the transmission mechanism;

[0020] The sprocket is fixed to the transmission mechanism and outputs the torque;

[0021] After the torque passes through the transmission mechanism, a part of the transmission mechanism components is fixed relative to the frame by controlling the fixing mechanism to change the transmission ratio.

[0022] The present application also provides a mid-mounted motor, comprising the above-mentioned mid-shaft transmission, and also comprising a motor, wherein the motor is connected to the mid-shaft or the transmission mechanism.

[0023] As can be seen from the above, the fixing mechanism of the present invention utilizes a ratchet-pawl mechanism, comprising a control pawl, a control cam, and a ratchet slot. When the control cam rotates, it drives the control pawl to swing, thereby locking or releasing the control pawl with the ratchet slot provided on the ring gear. When the control pawl engages the ratchet slot, it prevents the ring gear from rotating in one direction, thereby securing the ring gear. This mechanism offers advantages such as small size, light weight, simple structure, convenient control, easy assembly, and ease of maintenance.

[0024] Other features and advantages of the present application will be described in the following description, and in part will become apparent from the description, or understood by practicing the present application. The purposes and other advantages of the present application can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG1 is a schematic structural diagram of a central shaft transmission embodiment 1 of the present application.

[0026] FIG2 is a diagram of the first gear power transmission path of the mid-shaft transmission embodiment 1 of the present application.

[0027] FIG3 is a diagram of the second gear power transmission path of the mid-shaft transmission embodiment 1 of the present application.

[0028] FIG4 is a schematic structural diagram of a central shaft transmission embodiment 2 of the present application.

[0029] FIG5 is a diagram of the first gear power transmission path of the mid-shaft transmission embodiment 2 of the present application.

[0030] FIG6 is a diagram of the second gear power transmission path of the central shaft transmission embodiment 2 of the present application.

[0031] FIG7 is a diagram of the third gear power transmission path of the central shaft transmission embodiment 2 of the present application.

[0032] FIG8 is a diagram of the fourth gear power transmission path of the mid-shaft transmission embodiment 2 of the present application.

[0033] FIG9 is a schematic structural diagram of the central shaft transmission embodiment 3 of the present application.

[0034] FIG10 is a diagram of the first gear power transmission path of the central shaft transmission embodiment 3 of the present application.

[0035] FIG11 is a diagram of the second gear power transmission path of the central shaft transmission embodiment 3 of the present application.

[0036] FIG12 is a diagram of the third gear power transmission path of the central shaft transmission embodiment 3 of the present application.

[0037] FIG13 is a diagram of the fourth gear power transmission path of the central shaft transmission embodiment 3 of the present application.

[0038] FIG14 is a diagram of the fifth gear power transmission path of the central shaft transmission embodiment 3 of the present application.

[0039] FIG15 is a diagram of the sixth gear power transmission path of the central shaft transmission embodiment 3 of the present application.

[0040] FIG16 is a diagram of the seventh gear power transmission path of the central shaft transmission embodiment 3 of the present application.

[0041] Figure 17 is a power transmission path diagram of the eighth gear of the central shaft transmission embodiment 3 of the present application.

[0042] FIG18 is a schematic structural diagram of the mid-mounted motor embodiment 4 of the present application.

[0043] FIG19 is a schematic structural diagram of the mid-mounted motor embodiment 5 of the present application.

[0044] FIG20 is a schematic structural diagram of the mid-mounted motor embodiment 6 of the present application.

[0045] Figure 21 is a structural diagram of embodiment 7 of the mid-mounted motor of the present application.

[0046] FIG22 is a schematic structural diagram of the mid-mounted motor embodiment 8 of the present application.

[0047] Figure 23 is a structural diagram of embodiment 9 of the central shaft transmission of the present application.

[0048] Figure 24 is a power transmission path diagram of the middle shaft transmission embodiment 9 of the present application.

[0049] Figure 25 is a stereoscopic view of embodiment 9 of the mid-shaft transmission of the present application.

[0050] Figure 26 is a front view of the middle shaft transmission embodiment 9 of the present application.

[0051] Figure 27 is a longitudinal sectional view of the middle shaft transmission embodiment 9 of the present application.

[0052] Figure 28 is a stereoscopic view of Example 9 of the mid-shaft transmission (electric shift mechanism) of the present application.

[0053] FIG29 is a three-dimensional diagram of the fixing mechanism of the present application.

[0054] FIG30 is a front view of the fixing mechanism of the present application.

[0055] FIG31 is a cross-sectional view along line AA, line BB, line CC, and line DD in FIG29 .

[0056] Figure 32 is a stereoscopic view of embodiment 10 of the mid-shaft transmission (manual shift mechanism) of the present application.

[0057] Figure 33 is a stereoscopic view of embodiment 10 of the mid-shaft transmission (manual shift mechanism, fixed plate hidden) of the present application.

[0058] Figure 34 is a structural diagram of the mid-mounted motor embodiment 10 of the present application.

[0059] Figure 35 is one of the three-dimensional views of the mid-mounted motor embodiment 10 of the present application.

[0060] FIG36 is a second stereoscopic view of the mid-mounted motor embodiment 10 of the present application.

[0061] Figure 37 is the third stereoscopic view of the mid-mounted motor embodiment 10 of the present application.

[0062] FIG38 is the fourth stereoscopic view of the mid-mounted motor embodiment 10 of the present application.

[0063] Explanation of reference numerals: 1-central shaft, 2-transmission mechanism, 20-first planetary carrier, 200-second planetary carrier, 21-first planetary gear mechanism, 211-first sun gear, 212-first planetary gear, 213-first ring gear, 22-second planetary gear mechanism, 221-second sun gear, 222-second planetary gear, 223-second ring gear, 23-third planetary gear mechanism, 232-third planetary gear, 233-third ring gear, 24-fourth planetary gear mechanism, 241-fourth sun gear Yang gear, 242-fourth planetary gear, 243-fourth ring gear, 25-fifth planetary gear mechanism, 251-fifth sun gear, 252-fifth planetary gear, 253-fifth ring gear, 26-sixth planetary gear mechanism, 262-sixth planetary gear, 263-sixth ring gear, 27-seventh planetary gear mechanism, 272-seventh planetary gear, 273-seventh ring gear, 28-eighth planetary gear mechanism, 281-eighth sun gear, 282-eighth planetary gear, 283- Eighth ring gear, 2831-eighth ratchet groove, 29-ninth planetary gear mechanism, 291-ninth sun gear, 292-ninth planetary gear, 293-ninth ring gear, 2931-ninth ratchet groove, 2100-tenth planetary gear mechanism, 21002-tenth planetary gear, 21003-tenth ring gear, 210031-tenth ratchet groove, 2110-eleventh planetary gear mechanism, 21102-eleventh planetary gear, 21103-eleventh ring gear, 211031-eleventh ratchet groove, 2120-twelfth planetary gear mechanism, 21201-twelfth sun gear, 21202-twelfth planetary gear, 21203-twelfth ring gear, 3-fixing mechanism, 31-first fixing mechanism, 311-first control pawl, 312-first control cam, 3121- First control slot, 32-second fixing mechanism, 321-second control pawl, 322-second control cam, 3221-second control slot, 33-third fixing mechanism, 331-third control pawl, 332-third control cam, 3321-third control slot, 34-fourth fixing mechanism, 341-fourth control pawl, 342-fourth control cam, 3421-fourth control slot, 35-housing, 351-avoidance slot, 352-rotating shaft, 36-camshaft, 37-electric shift mechanism, 371-driving device, 372-first reduction mechanism, 373-buffer device, 374-gear feedback device, 38-manual shift mechanism, 381-fixed disk, 382-wire tube, 383-rotating disk, 3831-wire slot, 384-control wire, 4-one-way clutch assembly, 41-first one-way clutch assembly, 42-second one-way clutch assembly, 5-sprocket, 6-frame, 7-motor, 71-stator, 72-rotor, 8-second reduction gear, 81-first reduction gear, 82-second reduction gear, 83-third reduction gear,9-crank, 10-protective shell. DETAILED DESCRIPTION

[0064] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limiting the present invention.

[0065] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0066] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections, or mutual communication; direct connections or indirect connections through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0067] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0068] The disclosure below provides many different embodiments or examples for realizing different structures of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0069] The mid-shaft transmission of the present application is fixedly installed at the bottom in the middle of the vehicle's frame 6. The mid-shaft transmission includes a mid-shaft 1, a transmission mechanism 2, a fixing mechanism 3, a one-way clutch assembly 4 and a sprocket 5, wherein the two ends of the mid-shaft 1 are respectively fixedly connected to the crank 9, and the crank 9 is rotatably connected to the pedal. The rider transmits the generated torque to the mid-shaft 1 by stepping on the pedal, and then the mid-shaft 1 inputs it into the transmission mechanism 2. The transmission mechanism 2 is used to adjust the transmission ratio and output speed, and to achieve switching of different gears by changing the meshing relationship of different planetary gears. The sprocket 5 is fixed on the transmission mechanism 2 for outputting torque. The sprocket 5 then inputs the torque to the flywheel through chain drive or belt drive, driving the rear wheel of the vehicle to rotate.

[0070] This device can be used for bicycles, folding bicycles, Ebikes, electric-assisted bicycles, electric vehicles, electric motorcycles, cargo and freight electric vehicles, tricycles, scooters, electric scooters and other vehicles.

[0071] Figure 1 shows a schematic diagram of the structure of the mid-axle transmission of the present application. The transmission mechanism 2 includes multiple sets of planetary gear mechanisms. Compared to fixed-axis gear mechanisms, planetary gear mechanisms are simpler gear transmission mechanisms 2, consisting of two or more gears. These gears are mounted on a fixed shaft and transmit power and torque through meshing between the gears. In contrast, planetary gear mechanisms are more complex gear transmission mechanisms 2, consisting of three basic components: a sun gear, planetary gears, and a ring gear. The sun gear is located at the center, and the planetary gears rotate around the sun gear and mesh with the ring gear. By varying the position and motion of the planetary gears, different speed ratios, torque conversion, and reverse transmission can be achieved. Planetary gear transmissions are compact and low in height, enabling high torque transmission within limited space, making them particularly suitable for applications requiring high torque and a compact design. Bicycles require high component space utilization, and larger components can affect rider operability. Therefore, the use of planetary gear mechanisms can significantly reduce the overall dimensions of the mid-axle transmission.

[0072] Example 1

[0073] In this embodiment, two sets of planetary gear mechanisms are used, specifically including a first set of planetary gear mechanisms 21 and a second set of planetary gear mechanisms 22. The connection relationship and meshing relationship of the various parts of the planetary gear mechanisms are as follows:

[0074] The first planetary gear mechanism 21 includes a first sun gear 211, a first ring gear 213, and first planetary gears 212. The first planetary gears 212 are externally meshed with the first sun gear 211, and the first ring gear 213 is internally meshed with the first planetary gears 212.

[0075] The second planetary gear mechanism 22 includes a second sun gear 221, a second ring gear 223, and second planetary gears 222. The second planetary gears 222 are externally meshed with the second sun gear 221, and the second ring gear 223 is internally meshed with the second planetary gears 222.

[0076] The first planetary gear 212 and the second planetary gear 222 are hinged to the same planetary carrier, namely the first planetary carrier 20;

[0077] The first sun gear 211 and the second sun gear 221 are fixedly connected to the central shaft 1;

[0078] The first planet carrier 20 is rotatably supported on the central shaft 1 and one end of the first planet carrier 20 is fixedly connected to the sprocket 5 .

[0079] In this embodiment, two sets of planetary gear mechanisms are used to change the transmission ratio, and the fixing mechanism 3 is used to lock or release the ring gear of the planetary gear mechanism to achieve this.

[0080] The fixing mechanism 3 can be any mechanism that can make the ring gear stop from rotating motion, such as a ratchet pawl mechanism, a brake mechanism, a locking pin mechanism, etc. One end of the fixing mechanism 3 is connected to the frame 6, and the other end is connected to a part of the transmission mechanism 2. Under normal circumstances, the fixing mechanism 3 is in a non-working state, that is, the ring gear can rotate relative to the central axis 1. After the fixing mechanism 3 is working, the ring gear and the frame 6 are relatively fixed, and the ring gear cannot rotate.

[0081] There can be one or more fixing mechanisms 3, and the ring gears of the first set of planetary gear mechanisms 21 and the second set of planetary gear mechanisms 22 can be fixed by a separate fixing mechanism 3, which can also realize the change of transmission ratio. However, during the gear shifting process, the gear shifting must be quick and not delayed, and the time for switching between the two fixing mechanisms 3 needs to be controlled to a very small extent. However, this places high demands on the fixing mechanism 3 and the controller and control system that control it, making it difficult to achieve or the cost high.

[0082] In order to simplify the shift control of the mid-shaft transmission and reduce the volume of the mid-shaft transmission, a one-way clutch assembly 4 is provided to replace a fixing mechanism 3. The one-way clutch assembly 4 allows the parts to rotate in one direction and prevents rotation in the other direction.

[0083] The one-way clutch assembly 4 is positioned outside the ring gear of the transmission mechanism 2. One end of the one-way clutch assembly 4 is connected to the vehicle frame 6, and the other end is connected to the ring gear of the transmission mechanism 2. Under normal conditions, the permitted rotation direction of the one-way clutch assembly 4 is opposite to that of the ring gear. In other words, the ring gear is prevented from rotating in the unauthorized direction by the one-way clutch assembly 4, causing it to come to a standstill. The one-way clutch assembly 4 can be a roller clutch, a sprag clutch, a ratchet clutch, a friction clutch, an electromagnetic clutch, or other types.

[0084] Assume that the number of teeth of the first sun gear 211 is z1, the number of teeth of the first ring gear 213 is z2, the number of teeth of the first planetary gear 212 is z3, the number of teeth of the second sun gear 221 is z4, the number of teeth of the second ring gear 223 is z5, the number of teeth of the second planetary gear 222 is z6, the number of teeth of the third ring gear 233 is z7, the number of teeth of the third planetary gear 232 is z8, the number of teeth of the fourth sun gear 241 is z9, the number of teeth of the fourth ring gear 243 is z10, and the number of teeth of the fourth planetary gear 242 is z11.

[0085] FIG2 shows a power transmission path diagram of the first gear of the mid-shaft transmission embodiment 1 of the present application.

[0086] As shown in the figure, the first fixing mechanism 31 is in an inactive state. The torque generated by the rider's pedaling is input through the center axle 1. Since the first ring gear 213 is not fixed, according to the transmission characteristics of the planetary gear, the first ring gear 213 is in an idle state and does not output torque, which is equivalent to the failure of the first planetary gear mechanism 21. The one-way clutch assembly 4 is configured to prevent the rotation of the second ring gear 223. In other words, the one-way clutch assembly 4 is engaged, fixing the second ring gear 223 to the frame 6. The motion state of the second planetary gear mechanism 22 is now: the second sun gear 221 is the active state, the second ring gear 223 is fixed, and the first planetary carrier 20 is the driven state. This is a reduction transmission, i1 = (z4 + z5) / z4.

[0087] FIG3 shows a power transmission path diagram of the second gear of the central shaft transmission embodiment 1 of the present application.

[0088] As shown in the figure, at this time, the first fixing mechanism 31 is in the working state, that is, the first ring gear 213 is fixed by the first fixing mechanism 31. The torque generated by the rider's pedaling is input from the central shaft 1. According to the transmission characteristics of the planetary gear, the first sun gear 211 inputs, the first ring gear 213 is fixed, and the first planetary carrier 20 outputs. Since the number of teeth of the first ring gear 213 is the same as the number of teeth of the second ring gear 223, and the number of teeth of the first sun gear 211 is greater than the number of teeth of the second sun gear 221, according to the motion characteristic equation of the planetary gear mechanism,

[0089] n1+an2=(1+a)n3,a=z2 / z1

[0090] Wherein n1 is the rotation speed of the sun gear, n2 is the rotation speed of the ring gear, n3 is the rotation speed of the planet carrier, z1 is the number of teeth of the sun gear, z2 is the number of teeth of the ring gear, and z3 is the number of teeth of the first planet carrier 20.

[0091] Calculations show that the speed of the first planetary carrier 20 in the second gear is greater than that in the first gear. The speed of the first planetary carrier 20 is input into the second planetary gear mechanism 22. According to the kinematic equation, the speed of the second sun gear 221 remains constant. The increase in the speed of the first planetary carrier 20 causes the speed of the second ring gear 223 to increase and become non-zero. Furthermore, the rotation direction of the second ring gear 223 is the same as that of the second sun gear 221. At this point, the first one-way clutch assembly 41 is disengaged, and the second planetary gear mechanism 22 is deactivated. The same principle applies below and will not be further elaborated.

[0092] According to the transmission ratio calculation formula i = (z1 + z2) / z1, the first ring gear 213 has the same number of teeth as the second ring gear 223, and the first sun gear 211 has more teeth than the second sun gear 221. Therefore, the transmission ratio of the second gear is smaller than that of the first gear but greater than 1, indicating a reduction transmission. Therefore, i2 = (z1 + z2) / z1.

[0093] As can be seen from the above, by controlling the fixing mechanism 3 to lock or release the ring gear of the planetary gear mechanism, the one-way clutch assembly 4 is disengaged or engaged, causing the mid-shaft transmission to switch from the first gear to the second gear, thereby realizing the gear shifting function. Since only a single fixing mechanism 3 needs to be controlled, and there is no need to control two fixing mechanisms 3, the gear shifting process can be better controlled, and the gear shifting is rapid with an extremely short time interval, thus avoiding the phenomenon of stepping on the air. The volume of the one-way clutch assembly 4 is much smaller than that of the fixing mechanism 3, and it is low-cost and does not require separate control, making the mid-shaft transmission compact and reduced in size. The one-way clutch assembly 4 and the fixing mechanism 3 are both arranged on the outside of the ring gear of the transmission mechanism 2, which is convenient for processing and assembly.

[0094] Example 2

[0095] FIG4 shows a schematic structural diagram of embodiment 2, which differs from embodiment 1 in that a third set of planetary gear mechanisms 23 and a fourth set of planetary gear mechanisms 24 are added, which can provide more gears and has a different method of torque output.

[0096] The connection and meshing relationships of the various parts of the planetary gear mechanism are:

[0097] The first planetary gear mechanism 21 includes a first sun gear 211, a first ring gear 213, and first planetary gears 212. The first planetary gears 212 are externally meshed with the first sun gear 211, and the first ring gear 213 is internally meshed with the first planetary gears 212.

[0098] The second planetary gear mechanism 22 includes a second sun gear 221, a second ring gear 223, and second planetary gears 222. The second planetary gears 222 are externally meshed with the second sun gear 221, and the second ring gear 223 is internally meshed with the second planetary gears 222.

[0099] The third planetary gear mechanism 23 includes a third ring gear 233 and third planetary gears 232 , wherein the third ring gear 233 is internally meshed with the third planetary gears 232 ;

[0100] The fourth planetary gear mechanism 24 includes a fourth sun gear 241, a fourth ring gear 243, and fourth planetary gears 242. The fourth planetary gears 242 are externally meshed with the fourth sun gear 241, and the fourth ring gear 243 is internally meshed with the fourth planetary gears 242.

[0101] The first planetary gear 212, the second planetary gear 222, the third planetary gear 232 and the fourth planetary gear 242 are hinged to the same planetary carrier, namely the first planetary carrier 20. The third planetary gear 232 and the fourth planetary gear 242 are combined into a first double planetary gear.

[0102] The first sun gear 211 and the second sun gear 221 are fixedly connected to the central shaft 1;

[0103] The fourth sun gear 241 is rotatably supported on the central shaft 1 and one end of the fourth sun gear 241 is fixedly connected to the sprocket 5 .

[0104] In this embodiment, four planetary gear mechanisms are used to change the transmission ratio, and this is achieved by using a fixing mechanism 3 to lock or release the ring gears of the planetary gear mechanisms. The fixing mechanisms 3 are provided in two groups: a first fixing mechanism 31 and a second fixing mechanism 32. The one-way clutch assembly 4 is also provided in two groups: a first one-way clutch assembly 41 and a second one-way clutch assembly 42. Specifically, the first fixing mechanism 31 is provided on the outside of the first ring gear 213, the first one-way clutch assembly 41 is provided on the outside of the second ring gear 223, the second one-way clutch assembly 42 is provided on the outside of the third ring gear 233, and the second fixing mechanism 32 is provided on the outside of the fourth ring gear 243.

[0105] It should be noted that in Example 1, torque is input from the sun gear and output from the first planetary carrier 20, representing a simple reduction transmission. In contrast, in Example 2, torque is input from the sun gear, output from the first planetary carrier 20, and then input from the first planetary carrier 20 and output from the sun gear, representing a combined reduction and speed-increasing transmission. In practice, the midshaft transmission can also be a combined speed-increasing and reduction transmission, i.e., the planetary gear mechanism of the preceding stage is interchangeable with the planetary gear mechanism of the following stage. The specific conversion process is a technical solution that is readily apparent to those skilled in the art and will not be elaborated upon here.

[0106] FIG5 shows a power transmission path diagram of the first gear of the central shaft transmission embodiment 2 of the present application.

[0107] As shown in the figure, the first fixing mechanism 31 and the second fixing mechanism 32 are in an inoperative state, the first one-way clutch assembly 41 and the second one-way clutch assembly 42 are engaged, and the torque generated by the rider's pedaling is input through the bottom bracket 1. Since the first ring gear 213 and the fourth ring gear 243 are not fixed, according to the transmission characteristics of the planetary gear, the first ring gear 213 and the fourth ring gear 243 are in an idling state and do not output torque, which is equivalent to the failure of the first set of planetary gear mechanisms 21 and the fourth set of planetary gear mechanisms 24. The one-way clutch assembly 4 is configured to prevent the second ring gear 223 and the fourth ring gear 243 from rotating. In other words, the first one-way clutch assembly 41 is engaged to fix the second ring gear 223 to the frame 6, and the second one-way clutch assembly 42 is engaged to fix the third ring gear 233 to the frame 6. At this time, the motion states of the second group of planetary gear mechanisms 22 are: the second sun gear 221 is active, the second ring gear 223 is fixed, and the first planetary carrier 20 is driven. At this time, it is a reduction transmission. The motion states of the third group of planetary gear mechanisms 23 are: the first planetary carrier 20 is active, the third ring gear 233 is fixed, and the fourth sun gear 241 is driven. It is an NW transmission type (2Z-X mechanism). At this time, it is a speed increase transmission, i3=i1×1 / {1+(z7×z11) / (z9×z8)}.

[0108] FIG6 shows a power transmission path diagram of the second gear of the mid-shaft transmission embodiment 2 of the present application.

[0109] As shown in the figure, the first fixing mechanism 31 is inactive, while the second fixing mechanism 32 is active. This means that the fourth ring gear 243 is secured by the second fixing mechanism 32, the first one-way clutch assembly 41 is engaged, and the second one-way clutch assembly 42 is disengaged. The rider's pedaling torque is input through the center axle 1. Due to the transmission characteristics of the planetary gears, the first and third ring gears 213 and 233 are in an idling state, producing no torque. This effectively renders the first and third planetary gear mechanisms 21 and 23 inoperative.

[0110] At this time, the motion states of the second group of planetary gear mechanisms 22 are: the second sun gear 221 is active, the second ring gear 223 is fixed, and the first planetary carrier 20 is driven. At this time, it is a reduction transmission. The motion states of the fourth group of planetary gear mechanisms 24 are: the first planetary carrier 20 is active, the fourth ring gear 243 is fixed, and the fourth sun gear 241 is driven. At this time, it is a speed increase transmission, i4=i1×z9 / (z9+z10).

[0111] FIG7 shows a power transmission path diagram of the third gear of the mid-shaft transmission embodiment 2 of the present application.

[0112] As shown in the figure, at this time, the first fixing mechanism 31 is in an operating state, and the second fixing mechanism 32 is in an inoperative state, that is, the first ring gear 213 is fixed by the first fixing mechanism 31, the first one-way clutch assembly 41 is in a disengaged state, and the second one-way clutch assembly 42 is in an engaged state. The torque generated by the rider's pedaling is input from the central shaft 1. According to the transmission characteristics of the planetary gears, the second ring gear 223 and the fourth ring gear 243 are in an idling state and do not output torque to the outside, which is equivalent to the failure of the second set of planetary gear mechanisms 22 and the fourth set of planetary gear mechanisms 24.

[0113] At this time, the motion states of the first group of planetary gear mechanisms 21 are: the first sun gear 211 is active, the first ring gear 213 is fixed, and the first planetary carrier 20 is driven. At this time, it is a reduction transmission. The motion states of the third group of planetary gear mechanisms 23 are: the first planetary carrier 20 is active, the third ring gear 233 is fixed, and the fourth sun gear 241 is driven. At this time, it is a speed increase transmission, i5=i2×1 / {1+(z7×z11) / (z9×z8)}.

[0114] FIG8 shows a power transmission path diagram of the fourth gear of the mid-shaft transmission embodiment 2 of the present application.

[0115] As shown in the figure, both the first fixing mechanism 31 and the second fixing mechanism 32 are in operation. That is, the first ring gear 213 is secured by the first fixing mechanism 31, the fourth ring gear 243 is secured by the second fixing mechanism 32, and the first one-way clutch assembly 41 and the second one-way clutch assembly 42 are disengaged. The rider's pedaling torque is input through the center axle 1. Due to the transmission characteristics of the planetary gears, the second and third ring gears 223 and 233 are in an idling state and do not output torque, effectively rendering the second and third planetary gear mechanisms 22 and 23 inoperative.

[0116] At this time, the motion states of the first group of planetary gear mechanisms 21 are: the first sun gear 211 is active, the first ring gear 213 is fixed, and the first planetary carrier 20 is driven. At this time, it is a reduction transmission. The motion states of the fourth group of planetary gear mechanisms 24 are: the first planetary carrier 20 is active, the fourth ring gear 243 is fixed, and the fourth sun gear 241 is driven. At this time, it is a speed increase transmission, i6=i2×z9 / (z9+z10).

[0117] Example 3

[0118] FIG9 shows a schematic structural diagram of embodiment 3, which differs from embodiment 2 in that a fifth set of planetary gear mechanisms 25 and a sixth set of planetary gear mechanisms 26 are added to further provide more gear positions.

[0119] The connection and meshing relationships of the various parts of the planetary gear mechanism are:

[0120] The first planetary gear mechanism 21 includes a first sun gear 211, a first ring gear 213, and first planetary gears 212. The first planetary gears 212 are externally meshed with the first sun gear 211, and the first ring gear 213 is internally meshed with the first planetary gears 212.

[0121] The second planetary gear mechanism 22 includes a second sun gear 221, a second ring gear 223, and second planetary gears 222. The second planetary gears 222 are externally meshed with the second sun gear 221, and the second ring gear 223 is internally meshed with the second planetary gears 222.

[0122] The third planetary gear mechanism 23 includes a third ring gear 233 and third planetary gears 232 , wherein the third ring gear 233 is internally meshed with the third planetary gears 232 ;

[0123] The fourth planetary gear mechanism 24 includes a fourth sun gear 241, a fourth ring gear 243, and fourth planetary gears 242. The fourth planetary gears 242 are externally meshed with the fourth sun gear 241, and the fourth ring gear 243 is internally meshed with the fourth planetary gears 242.

[0124] The fifth planetary gear mechanism 25 includes a fifth sun gear 251, a fifth ring gear 253, and fifth planetary gears 252. The fifth planetary gears 252 are externally meshed with the fifth sun gear 251, and the fifth ring gear 253 is internally meshed with the fifth planetary gears 252.

[0125] The sixth planetary gear mechanism 26 includes a sixth ring gear 263 and sixth planetary gears 262 , wherein the sixth ring gear 263 is internally meshed with the sixth planetary gears 262 ;

[0126] The first planetary gear 212, the second planetary gear 222, the third planetary gear 232, the fourth planetary gear 242, the fifth planetary gear 252 and the sixth planetary gear 262 are hinged to the same planetary carrier, i.e., the first planetary carrier 20. The third planetary gear 232 and the fourth planetary gear 242 are combined into a first double planetary gear, and the fifth planetary gear 252 and the sixth planetary gear 262 are combined into a second double planetary gear.

[0127] The fourth sun gear 241 and the fifth sun gear 251 are combined into a double sun gear;

[0128] The fourth sun gear 241 and the fifth sun gear 251 are rotatably supported on the central shaft 1 and one end of each is fixedly connected to the sprocket 5 .

[0129] One end of the fixing mechanism 3 is connected to the frame 6, and the other end is connected to the ring gear. Specifically, the fixing mechanism 3 includes a first fixing mechanism 31, a second fixing mechanism 32, a third fixing mechanism 33 and a fourth fixing mechanism 34. One end of the first fixing mechanism 31 is connected to the frame 6, and the other end is connected to the first ring gear 213. One end of the second fixing mechanism 32 is connected to the frame 6, and the other end is connected to the fourth ring gear 243. One end of the third fixing mechanism 33 is connected to the frame 6, and the other end is connected to the fifth ring gear 253. One end of the fourth fixing mechanism 34 is connected to the frame 6, and the other end is connected to the sixth ring gear 263. One end of the one-way clutch assembly 4 is connected to the frame 6, and the other end is connected to another part of the ring gear. The one-way clutch assembly 4 specifically includes a first one-way clutch assembly 41 and a second one-way clutch assembly 42. One end of the first one-way clutch assembly 41 is connected to the frame 6, and the other end is connected to the second ring gear 223. One end of the second one-way clutch assembly 42 is connected to the frame 6, and the other end is connected to the third ring gear 233.

[0130] The schematic diagram of the power transmission path of Example 3 is shown in Figures 10 to 17. It has eight gears, and the transmission method is not essentially different from that of Example 2, which will not be repeated. It should be noted that the third, fourth, fifth, and sixth sets of planetary gear mechanisms 26 are all speed-increasing transmissions, so only one one-way clutch assembly 4 can be set, and multiple one-way clutch assemblies 4 cannot be set, otherwise they will interfere with each other, causing the first planetary carrier 20 to generate alternating stress, which in turn causes the mid-shaft transmission to generate vibration and abnormal noise, and even cracks and plastic deformation.

[0131] Example 4

[0132] The present application also provides a mid-mounted motor, including the above-mentioned mid-shaft transmission, so that the mid-mounted motor has both a shifting function and an electric power assist function. As shown in Figure 18, the difference from Example 1 is that a motor 7 and a second reduction mechanism 8 are added. In this embodiment, the motor 7 is connected to the transmission mechanism 2. Specifically, the axis of the output shaft of the motor 7 is parallel to the axis of the mid-shaft 1. The motor 7 is connected to the first planetary carrier 20 of the transmission mechanism 2 through the second reduction mechanism 8. The second reduction mechanism 8 can be a driving cylindrical gear with a small number of teeth and a driven cylindrical gear with a large number of teeth that are externally meshed with each other. The driving cylindrical gear is installed on the output shaft of the motor 7, and the driven cylindrical gear is installed on the outer peripheral surface of the first planetary carrier 20 or the gear teeth are directly processed on the outer peripheral surface of the first planetary carrier 20.

[0133] When the motor 7 is working, in addition to the torque generated by the rider's pedaling, there is also the torque generated by the motor 7. The two torques are superimposed and output to the sprocket 5, allowing the rider to achieve a higher riding speed or a longer riding distance in an effortless riding manner.

[0134] The mid-shaft transmissions of Examples 1-3 can all obtain electric power assistance through the connection method of the motor 7.

[0135] Compared with the rear motor (hub motor) with a shifting function, the mid-mounted motor with a shifting function has a speed-changing structure not on the rear wheel but on the frame 6. Therefore, when it is impacted on a rough road, the impact will not be directly transmitted to the hub through the rim and spokes, but will also need to be transmitted through the frame 6. The frame 6 has a certain vibration absorption function, which greatly reduces the impact force. It is relatively not easily affected by external forces and is not easy to bump, making the mid-mounted motor more durable.

[0136] The weight of the rear motor is concentrated on the rear wheels, which is not conducive to the vehicle's take-off and jumping. The weight of the mid-mounted motor is concentrated at the lower center of gravity of the frame, which has a relatively small impact on the balance of the entire vehicle and can greatly improve the handling performance.

[0137] Example 5

[0138] FIG19 shows a schematic structural diagram of Example 5 of the central motor of the present application. The difference from Example 4 is that the motor 7 is connected to the central shaft 1 via a second reduction mechanism 8. As in Example 4, the second reduction mechanism 8 can be a driving cylindrical gear with a small number of teeth and a driven cylindrical gear with a large number of teeth that mesh externally with each other. The driving cylindrical gear is mounted on the output shaft of the motor 7, and the driven cylindrical gear is mounted on the outer circumference of the central shaft 1, or the gear teeth are directly machined on the outer circumference of the central shaft 1. This can also achieve the effect of electric power assistance.

[0139] The second reduction mechanism 8 is a type of gear transmission. The second reduction mechanism 8 can also be a chain transmission, a belt transmission, etc.

[0140] It is worth noting that the second speed reduction mechanism 8 can be set at a position close to the sprocket 5 or at a position far away from the sprocket 5, and the specific setting position depends on the actual situation.

[0141] Example 6

[0142] Figure 20 shows a structural schematic diagram of embodiment 6 of the central motor of the present application. The difference from embodiment 5 is that the shaft of the motor 7 and the central shaft 1 are arranged perpendicular to each other. For this reason, the second reduction mechanism 8 adopts bevel gears, and the active bevel gear with a small number of teeth is installed on the output shaft of the motor 7, and the driven bevel gear with a large number of teeth is installed on the outer peripheral surface of the central shaft 1 or the gear teeth are directly processed on the outer peripheral surface of the central shaft 1.

[0143] Example 7

[0144] Figure 21 shows a structural schematic diagram of embodiment 7 of the mid-mounted motor of the present application. The difference from embodiment 4 is that the motor 7 is split into main parts such as the stator 71 and the rotor 72, and the motor 7 is arranged inside the first planetary carrier 20. The motors 7 of embodiments 4-6 are all arranged outside the mid-shaft transmission, while the motor 7 of this embodiment is arranged inside the first planetary carrier 20, which can make the structure of the mid-mounted motor more compact.

[0145] As shown in the figure, the stator 71 of the motor 7 is fixed to a certain part of the frame 6 and is not connected to the central shaft 1. The rotor 72 is arranged outside the stator 71 and is fixedly connected to the first planetary carrier 20, forming an inner stator 71 and outer rotor 72 motor 7 structure. When the motor 7 is energized, it drives the rotor 72 to rotate at high speed, and the rotor 72 drives the first planetary carrier 20 to output torque, so that the effect of torque superposition can also be achieved.

[0146] Example 8

[0147] FIG22 shows a schematic diagram of the structure of the embodiment 8 of the mid-mounted motor of the present application. The difference from embodiment 5 is that the positions of the stator 71 and the rotor 72 of the motor are interchanged. Specifically, the stator 71 of the motor 7 is fixed to a certain part of the frame 6 and is not connected to the central axis 1. The rotor 72 is arranged inside the stator 71 and is fixedly connected to the central axis 1, forming an outer stator 71 and inner rotor 72 motor 7 structure. When the motor 7 is energized, it drives the rotor 72 to rotate at high speed, and the rotor 72 drives the central axis 1 to output torque, because it can also achieve the effect of torque superposition. Since the torque input from the central axis 1 and the torque output from the motor 7 both act on the central axis 1 and share the same transmission mechanism 2, the motor 7 does not need to be equipped with an additional second reduction mechanism 8, which further reduces the volume of the entire device.

[0148] Example 9

[0149] Figure 23 shows a schematic structural diagram of embodiment 9 of the central shaft transmission of the present application, Figure 25 shows a perspective view of embodiment 9 of the central shaft transmission of the present application, Figure 26 shows a front view of embodiment 9 of the central shaft transmission of the present application, and Figure 27 shows a longitudinal cross-sectional view of embodiment 9 of the central shaft transmission of the present application. The difference from embodiment 3 lies in the adjustment of the positioning of the planetary gear mechanisms. In embodiment 3, the first and second planetary gear mechanisms 21 and 22 each have a sun gear input torque and a planetary carrier output torque, representing a reduction transmission. The third, fourth, fifth, and sixth planetary gear mechanisms 23 and 24, respectively, each have a planetary carrier input torque and a sun gear output torque, representing a speed-increasing transmission. According to the power calculation formula, under equal power conditions, the lower the speed, the greater the torque. Consequently, the torque borne by the various components of the first and second planetary gear mechanisms 21 and 22 will increase, exceeding the torque input from the central shaft 1. To ensure service life, the wall thickness of the sun gear, planetary gears, and ring gear will be increased, resulting in an increase in the volume and weight of the entire central shaft transmission.

[0150] After adjusting the setting position of the planetary gear mechanism, the planetary gear mechanism of the speed-increasing transmission is set at the torque input end, and the planetary gear mechanism of the speed-reducing transmission is set at the torque output end. Then, the torque after passing through the planetary gear mechanism of the speed-increasing transmission will become smaller, and the wall thickness of each part of the planetary gear mechanism of the speed-increasing transmission can be appropriately thinned, thereby achieving the purpose of reducing the volume and weight of the mid-shaft transmission.

[0151] In this embodiment, a seventh planetary gear mechanism 27, an eighth planetary gear mechanism 28, a ninth planetary gear mechanism 29, a tenth planetary gear mechanism 2100, an eleventh planetary gear mechanism 2110, and a twelfth planetary gear mechanism 2120 are provided, among which the seventh planetary gear mechanism 27, the eighth planetary gear mechanism 28, the ninth planetary gear mechanism 29 and the tenth planetary gear mechanism 2100 are speed-increasing transmissions, and the eleventh planetary gear mechanism 2110 and the twelfth planetary gear mechanism 2120 are speed-reducing transmissions.

[0152] The connection and meshing relationships of the various parts of the planetary gear mechanism are:

[0153] The seventh planetary gear mechanism 27 includes a seventh planetary gear 272 and a seventh ring gear 273 , wherein the seventh ring gear 273 is internally meshed with the seventh planetary gear 272 ;

[0154] The eighth planetary gear mechanism 28 includes an eighth sun gear 281, an eighth planetary gear 282, and an eighth ring gear 283. The eighth planetary gear 282 is externally meshed with the eighth sun gear 281, and the eighth ring gear 283 is internally meshed with the eighth planetary gear 282.

[0155] The ninth planetary gear mechanism 29 includes a ninth sun gear 291 , ninth planetary gears 292 , and a ninth ring gear 293 . The ninth planetary gear 292 is externally meshed with the ninth sun gear 291 , and the ninth ring gear 293 is internally meshed with the ninth planetary gears 292 .

[0156] The tenth planetary gear mechanism 2100 includes a tenth planetary gear 21002 and a tenth ring gear 21003 , wherein the tenth ring gear 21003 is internally meshed with the tenth planetary gear 21002 ;

[0157] The eleventh planetary gear mechanism 2110 includes an eleventh planetary gear 21102 and an eleventh ring gear 21103 , wherein the eleventh ring gear 21103 is internally meshed with the eleventh planetary gear 21102 ;

[0158] The twelfth planetary gear mechanism 2120 includes a twelfth sun gear 21201, a twelfth planetary gear 21202, and a twelfth ring gear 21203. The twelfth planetary gear 21202 is externally meshed with the twelfth sun gear 21201, and the twelfth ring gear 21203 is internally meshed with the twelfth planetary gear 21202.

[0159] The seventh planetary gear 272, the eighth planetary gear 282, the ninth planetary gear 292, and the tenth planetary gear 21002 are hingedly connected to the first planetary carrier 20. The ninth planetary gear 292 and the tenth planetary gear 21002 are hingedly connected to the second planetary carrier 200. The seventh planetary gear 272 and the eighth planetary gear 282 are combined into a double planetary gear. The ninth planetary gear 292 and the tenth planetary gear 21002 are combined into a double planetary gear. The eleventh planetary gear 21102 and the twelfth planetary gear 21202 are combined into a double planetary gear.

[0160] The eighth sun gear 281, the ninth sun gear 291, and the twelfth sun gear 21201 are combined into a triple sun gear, which is cylindrical and sleeved on the central shaft 1 and can rotate relative to the central shaft 1;

[0161] One end of the second planet carrier 200 is fixedly connected to the sprocket 5 .

[0162] One end of the fixing mechanism 3 is connected to the frame 6, and the other end is connected to the ring gear. Specifically, the fixing mechanism 3 includes a first fixing mechanism 31, a second fixing mechanism 32, a third fixing mechanism 33 and a fourth fixing mechanism 34. One end of the first fixing mechanism 31 is connected to the frame 6, and the other end is connected to the eighth ring gear 283. One end of the second fixing mechanism 32 is connected to the frame 6, and the other end is connected to the ninth ring gear 293. One end of the third fixing mechanism 33 is connected to the frame 6, and the other end is connected to the tenth ring gear 21003. One end of the fourth fixing mechanism 34 is connected to the frame 6, and the other end is connected to the eleventh ring gear 21103. One end of the one-way clutch assembly 4 is connected to the frame 6, and the other end is connected to another part of the ring gear. The one-way clutch assembly 4 specifically includes a first one-way clutch assembly 41 and a second one-way clutch assembly 42. One end of the first one-way clutch assembly 41 is connected to the frame 6, and the other end is connected to the seventh ring gear 273. One end of the second one-way clutch assembly 42 is connected to the frame 6, and the other end is connected to the twelfth ring gear 21203.

[0163] Figure 24 is a power transmission path diagram of a certain gear of the middle shaft transmission embodiment 9 of the present application.

[0164] As shown in the figure, at this time, the first fixing mechanism 31 and the fourth fixing mechanism 34 are in the working state, the first one-way clutch assembly 41 and the second one-way clutch assembly 42 are in the disengaged state, and the torque generated by the rider's pedaling is input from the central shaft 1. Since the seventh ring gear 273, the ninth ring gear 293, the tenth ring gear 21003, and the twelfth ring gear 21203 are not fixed, according to the transmission characteristics of the planetary gears, the seventh ring gear 273, the ninth ring gear 293, the tenth ring gear 21003, and the twelfth ring gear 21203 are in the idling state and do not output torque to the outside, which is equivalent to the failure of the seventh group of planetary gear mechanisms 27, the ninth group of planetary gear mechanisms 29, the tenth group of planetary gear mechanisms 2100, and the twelfth group of planetary gear mechanisms 2120. At this time, the motion states of the eighth planetary gear mechanism 28 are: the first planetary carrier 20 is active, the eighth ring gear 283 is fixed, and the eighth sun gear 281 is active. At this time, it is a speed-increasing transmission. The motion states of the eleventh planetary gear mechanism 2110 are: the twelfth sun gear 21201 is active, the eleventh ring gear 21103 is fixed, and the second planetary carrier 200 is driven. At this time, it is a speed-reducing transmission.

[0165] The power transmission path diagrams of other gears are similar to the power transmission path diagrams shown in Figures 10 to 17 of Example 3, and will not be repeated here.

[0166] Figure 29 is a perspective view of the fixing mechanism 3 of the present application. Figure 30 is a front view of the fixing mechanism 3 of the present application.

[0167] In this embodiment, the fixing mechanism 3 adopts a ratchet and pawl mechanism. Compared with the brake mechanism, the ratchet and pawl mechanism has the characteristics of simple structure, convenient control, easy assembly, and easy maintenance. The reason is that since the brake mechanism requires a brake disc, a hydraulic cylinder and a brake caliper, the hydraulic cylinder drives the brake caliper to clamp the brake disc to achieve fixation. However, the hydraulic cylinder requires hydraulic oil as a medium to drive the brake caliper to move, which makes the fixing mechanism 3 too large, and the hydraulic oil requires strict sealing conditions, otherwise it is easy to leak and cause the fixing mechanism 3 to fail.

[0168] The fixing mechanism 3 includes a control pawl and a control cam. The two ends of the control pawl are provided with claws. The middle of the control pawl is rotatably provided on a fulcrum.

[0169] The claw at one end of the control pawl is in abutment with the control cam and is slidably connected. When the control cam rotates, the control cam will drive the control pawl to swing, thereby locking or releasing the driving control pawl with the ratchet groove set on the ring gear. When the control pawl engages with the ratchet groove, it will prevent the ring gear from rotating in one direction, thereby achieving the function of fixing the ring gear.

[0170] Because the control pawl needs to resist the force exerted on it by the ratchet groove, it is necessary to effectively fix the control pawl. In this embodiment, a housing 35 is provided outside the transmission mechanism 2, and the housing 35 is connected to the frame 6. The outer circumference of the housing 35 is provided with an avoidance groove 351 that enables the control pawl to contact the ratchet groove. Since there are four control pawls, namely the first control pawl 311, the second control pawl 321, the third control pawl 331, and the fourth control pawl 341, four avoidance grooves 351 are also provided. The housing 35 is cylindrical, and the inner diameter of the housing 35 is slightly larger than the outer diameter of the gear ring of the transmission mechanism 2. A rotating shaft 352 is fixedly provided on the outer side of the housing 35. The rotating shaft 352 passes through the four control pawls in sequence and is hinged to each of them, allowing the control pawls to swing around their axes with the rotating shaft 352 as the fulcrum.

[0171] In order to regularly control the fixation of the ring gear, a first control cam 312, a second control cam 322, a third control cam 332, and a fourth control cam 342 are respectively provided to control the control pawls, and the four control cams are set on the same camshaft 36, which can ensure the synchronous rotation of the four control cams to ensure accurate shifting of the mid-shaft transmission.

[0172] As shown in Figure 31, the outer peripheral surface of the first control cam 312 is always against one end of the first control pawl 311. During the rotation of the first control cam 312, one end of the first control pawl 311 slides with the outer peripheral surface of the first control cam 312. At this time, the first control pawl 311 will not contact the first ratchet groove, and the seventh gear ring 273 rotates normally. A first control groove 3121 is set on the outer peripheral surface of the first control cam 312. When one end of the first control pawl 311 slides into the first control groove 3121, the first control pawl 311 swings. When the claw part of the first control pawl 311 close to the seventh gear ring 273 is stuck in the first ratchet groove, the seventh gear ring 273 is prevented from rotating in one direction.

[0173] A torsion spring can be set on the rotating shaft 352, one end of the torsion spring is connected to one end of the control pawl, and the other end of the torsion spring is connected to the housing 35. The torsion spring applies a force toward the ratchet groove to the control pawl, and at the same time the control pawl is against the outer peripheral surface of the control cam.

[0174] Similarly, a second control groove 3221, a third control groove 3321, and a fourth control groove 3421 are respectively provided on the second control cam 322, the third control cam 332, and the fourth control cam 342. Since the seventh planetary gear mechanism 27, the eighth planetary gear mechanism 28, the ninth planetary gear mechanism 29, and the tenth planetary gear mechanism 2100 share the same first planetary carrier 20, if more than two ring gears are fixed at the same time, the planetary gear mechanism will get stuck. Therefore, only one ring gear can be fixed. Therefore, the opening angles of the first control groove 3121, the second control groove 3221, and the third control groove 3321 are all different. This ensures that when rotating to a specific gear angle, only one control pawl is stuck in the control groove.

[0175] Since the eleventh planetary gear mechanism 2110 and the twelfth planetary gear mechanism 2120 share the second planet carrier 200 , the groove type of the fourth control groove 3421 depends on the actual gear shifting situation.

[0176] The control pawl rotates around the axis of the rotating shaft 352, with the axis center of the rotating shaft 352 as the fulcrum, to form a lever. A force-saving lever or a force-consuming lever can be formed by adjusting the distance from the contact point between the control pawl and the control cam to the fulcrum, and the distance from the contact point between the control pawl and the ratchet groove to the fulcrum.

[0177] If the distance from the contact point between the control pawl and the control cam to the fulcrum is greater than the distance from the contact point between the control pawl and the ratchet groove to the fulcrum, a force-saving lever is formed. Since the control pawl is stuck in the ratchet groove, the two will generate a larger force. Then, during the rotation process, the driving device 371 can use a smaller force to generate a larger output force, which can more easily control the pawl to disengage from the ratchet groove. It is suitable for a fixing mechanism 3 that can generate a larger force, such as the eighth group of planetary gear mechanisms 28, the ninth group of planetary gear mechanisms 29, and the tenth group of planetary gear mechanisms 2100 of the reduction transmission.

[0178] If the distance from the contact point between the control pawl and the control cam to the fulcrum is smaller than the distance from the contact point between the control pawl and the ratchet groove to the fulcrum, a force-consuming lever is formed. Then, during the rotation of the driving device 371, at the same rotation angle, the displacement of the control pawl swing is larger and the gear shifting speed is faster. It is suitable for a fixed mechanism 3 that does not generate a large force, such as the eleventh planetary gear mechanism 2110 of the speed-increasing transmission.

[0179] In order to drive the camshaft 36 to rotate, in this embodiment, an electric shift mechanism 37 is used for driving. The electric shift mechanism 37 includes a driving device 371. The driving device 371 is an encoder motor 7. The encoder motor 7 can obtain information such as the position, speed and angle of the motor 7 movement in real time through the encoder, and has high measurement accuracy and is suitable for application scenarios with high requirements on precision such as position, speed and angle.

[0180] The output end of the driving device 371 is connected to the first reduction mechanism 372, which can be a multi-stage gear reducer. The torque of the driving device 371 is increased through the first reduction mechanism 372. A buffer device 373 is also provided at the end of the camshaft 36. If the camshaft 36 gets stuck during the gear shifting process, the buffer device 373 can absorb the torque generated by the driving device 371 and play a buffering role. It will not cause damage to components or burn out of the driving device 371, and can effectively extend the service life of the driving mechanism.

[0181] In order to obtain the gear information of the mid-shaft transmission in real time, a gear feedback device 374 is also provided at the end of the camshaft 36. The gear feedback device 374 includes a magnet, a circuit board, and a plurality of Hall elements provided on the circuit board. In this embodiment, the mid-shaft transmission is provided with eight gears, so eight Hall elements are provided accordingly. The magnet is mounted on a swing arm fixed to the camshaft 36. When the driving device 371 drives the camshaft 36 to rotate, the magnet on the swing arm sweeps across the Hall element. The Hall element senses the change in magnetic field strength and generates a corresponding pulse. Therefore, the gear position can be determined by obtaining the pulse signal.

[0182] Vehicles using a mid-axle transmission also feature a speed feedback mechanism, such as a GPS chip that acquires location information and calculates the vehicle's speed. In automatic mode, the rider does not need to perform any operation; the mid-axle transmission shifts gears based on vehicle speed. For example, when the vehicle speed reaches 10 kilometers per hour, it automatically shifts from first gear to second gear; or when the vehicle speed drops below 10 kilometers per hour, it automatically shifts from second gear to first gear. Riders can switch to manual mode to freely change gears according to actual road conditions, improving riding flexibility, or switch to free mode for automatic gear changes, enhancing riding comfort.

[0183] Alternatively, the middle shaft transmission may have a built-in cadence sensor and a torque sensor to obtain the size of the rider's pedaling torque and the speed of the pedaling frequency, and based on the internal algorithm, comprehensively judge whether the rider is in an uphill state, a rapid acceleration and deceleration state on flat ground, a slow acceleration and deceleration state on flat ground, or a downhill state, and automatically control the drive device 371 to shift gears, thereby achieving the effect of automatic shifting.

[0184] Figure 32 is a stereoscopic view of embodiment 10 of the central shaft transmission (manual shift mechanism 38) of the present application, and Figure 33 is a stereoscopic view of embodiment 10 of the central shaft transmission (manual shift mechanism 38, with the fixed plate 381 hidden) of the present application.

[0185] In this embodiment, the camshaft 36 is driven by a manual shift mechanism 38, and the manual shift mechanism 38 includes a fixed disk 381, a rotating disk 383, a control line 384 and a shifter that drives the control line 384 to move. A through hole is provided in the middle of the fixed disk 381, and the rotating disk 383 is sleeved inside the fixed disk 381 and can rotate relative to the fixed disk 381. The fixed disk 381 can be fixed to any non-moving part of the mid-shaft transmission or the frame 6. A groove is provided above the fixed disk 381, and a wire tube 382 is fixedly installed in the groove. The arrangement position of the wire tube 382 is set along the tangential direction of the rotating disk 383, and the control line 384 passes through the wire tube 382 from top to bottom and is connected to the rotating disk 383.

[0186] To enable the control wire 384 to drive the camshaft 36 to rotate, a spiral wire groove 3831 is provided on the outer circumference of the rotating disk 383. The control wire 384 is wound along the wire groove 3831 and fixed at one end to a point on the rotating disk 383. When the control wire 384 is pulled upward by the shifter, the control wire 384 drives the rotating disk 383 to rotate, thereby driving the camshaft 36 fixed to the rotating disk 383 to rotate. When the control wire 384 is released by the shifter, the rotating disk 383 rotates in the opposite direction under the action of the elastic return member, thereby driving the camshaft 36 fixed to the rotating disk 383 to rotate in the opposite direction.

[0187] The control line 384 is usually made of a wire material that is not easily deformed, such as a steel wire.

[0188] Compared with the electric shift mechanism 37, the manual shift mechanism 38 has fewer parts, a simpler structure, does not require electric drive, does not involve complex electronic components and electrical systems, and has high reliability. However, the control line 384 will rust and stretch after long-term use, causing the control line 384 to be unable to pull or release the camshaft 36 at the same distance, thereby causing difficulty in shifting, frustration, or inability to shift.

[0189] Example 10

[0190] Figure 34 is a structural schematic diagram of embodiment 10 of the center-mounted motor 7 of the present application, Figure 35 is one of the stereoscopic diagrams of embodiment 10 of the center-mounted motor 7 of the present application, Figure 36 is a second stereoscopic diagram of embodiment 10 of the center-mounted motor 7 of the present application, Figure 37 is a third stereoscopic diagram of embodiment 10 of the center-mounted motor 7 of the present application, and Figure 38 is a fourth stereoscopic diagram of embodiment 10 of the center-mounted motor 7 of the present application.

[0191] In this embodiment, a second reduction mechanism 8 is provided at the output end of the motor 7. The second reduction mechanism 8 includes a first reduction gear 81, a second reduction gear 82, and a third reduction gear 83. The first reduction gear 81 is mounted on the output shaft of the motor 7, and the third reduction gear 83 is mounted on the second planetary carrier 200 of the transmission mechanism 2. The second reduction gear 82 is mounted between the first reduction gear 81 and the third reduction gear 83. The number of teeth of the first reduction gear 81, the second reduction gear 82, and the third reduction gear 83 increases successively. The second reduction mechanism 8 forms a two-stage reduction, which reduces the speed of the motor 7 to increase the torque of the motor 7. The rider pedals to generate torque that passes through the middle shaft transmission and is then added to the torque generated by the motor 7, and finally output to the sprocket 5.

[0192] A protective shell 10 is provided on the outside of the central motor 7. The protective shell 10 protects all electronic components and mechanical components inside to prevent damage from external factors such as collision, scratches, water and dust. A part of the protective shell 10 is made of metal material, which can cool the motor 7 and transfer the heat inside the motor 7 to the outside through heat conduction to ensure the normal operation of the central motor 7.

[0193] The fixing end of the fixing mechanism 3 is first connected to the protective shell 10 , and then the protective shell 10 is connected to the vehicle frame 6 , thereby achieving the purpose of indirect connection between the fixing mechanism 3 and the vehicle frame 6 .

[0194] Throughout this specification, references to terms such as "one embodiment," "certain embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" indicate that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the exemplary use of these terms does not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be incorporated in any suitable manner in any one or more embodiments or examples.

[0195] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. A fixing mechanism, characterized in that: It comprises a control pawl, a control cam and a ratchet groove, wherein the ratchet groove is formed on a gear ring of a transmission mechanism (2), the control pawl is connected to the control cam, and the control cam rotates to make the control pawl engage with or disengage from the ratchet groove.

2. The fixing mechanism according to claim 1, characterized in that: One end of the control pawl is slidably connected to the control cam, and the control cam is provided with a control groove. When one end of the control pawl slides into the control groove, the other end of the control pawl engages with the ratchet groove.

3. The fixing mechanism according to claim 1, characterized in that: The control pawl rotates around the fulcrum to form a labor-saving lever or a labor-intensive lever.

4. The fixing mechanism according to claim 1, characterized in that: It also includes a housing (35), the housing (35) is equipped with a rotating shaft (352), and the control pawl is rotatably connected to the rotating shaft (352).

5. The fixing mechanism according to claim 1, characterized in that: A plurality of control cams are provided, and the plurality of control cams are arranged on a camshaft (36).

6. The fixing mechanism according to claim 5, characterized in that: The camshaft (36) is driven by an electric shift mechanism (37) or a manual shift mechanism (38).

7. The fixing mechanism according to claim 6, characterized in that: The electric gear shift mechanism (37) comprises a driving device (371), the output end of the driving device (371) is connected to a first speed reduction mechanism (372) and a camshaft (36), and a buffer device (373) and a gear position feedback device (374) are also provided between the driving device (371) and the camshaft (36).

8. The fixing mechanism according to claim 6, characterized in that: The manual shift mechanism (38) comprises a fixed disk (381) and a rotating disk (383) capable of rotating relative to the fixed disk (381); the rotating disk (383) is provided with a wire groove (3831); a wire tube (382) is fixedly installed on the fixed disk (381); a control wire (384) passes through the wire tube (382), is wound around the wire groove (3831) of the rotating disk (383), and is fixed to the rotating disk (383).

9. A mid-axle transmission, characterized in that: The invention comprises a fixing mechanism according to any one of claims 1 to 8, wherein one end of the fixing mechanism (3) is connected to a vehicle frame (6), and the other end of the fixing mechanism (3) is connected to a part of a transmission mechanism (2), and further comprises: A middle shaft (1), the middle shaft (1) being rotatably supported on a frame (6), and torque being input from the middle shaft (1); A transmission mechanism (2), the transmission mechanism (2) being connected to the central shaft (1), the transmission mechanism (2) having at least one transmission ratio; A one-way clutch assembly (4), one end of which is connected to the vehicle frame (6) and the other end of which is connected to another part of the transmission mechanism (2); The sprocket (5) is fixed on the transmission mechanism (2) to output the torque; After the torque passes through the transmission mechanism (2), a part of the components of the transmission mechanism (2) is fixed relative to the vehicle frame (6) by controlling the fixing mechanism (3) to change the transmission ratio.

10. A mid-mounted motor, characterized in that: It comprises the middle shaft transmission as claimed in claim 9, characterized in that it also comprises a motor (7), wherein the motor (7) is connected to the middle shaft (1) or the transmission mechanism (2).

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