A mid-shaft transmission, a mid-mounted motor and a vehicle

Abstract

The utility model belongs to the technical field of transmission, and particularly relates to a mid-shaft transmission, a mid-mounted motor and a vehicle. The mid-shaft transmission provided by the present application comprises: a transmission mechanism, comprising more than two gear sets, a first transmission shaft and a second transmission shaft, each gear set comprising a pair of gears meshing with each other, the gears of the gear sets are respectively arranged on the first transmission shaft and the second transmission shaft, and the transmission mechanism has at least two transmission ratios; an input component connected to the first transmission shaft for inputting torque to the first transmission shaft; an output component connected to the gear set for outputting torque; a shift mechanism for switching different gear sets to change the transmission ratio of the transmission mechanism; a shift assist mechanism, when the shift mechanism cannot switch different gear sets to work, the torque of the second transmission shaft is transmitted to the shift mechanism through the shift assist mechanism to smoothly complete the shift operation.

Description

Technical Field

[0001] The utility model belongs to the technical field of transmissions, and in particular relates to a mid-axle transmission, a mid-mounted motor and a vehicle. Background Art

[0002] Chinese patent document CN116816928A discloses a gearbox, including a box-type transmission device and a shift control system, wherein the box-type transmission device includes a box body, a main shaft and a secondary shaft installed in parallel on the box body, at least one main shaft gear is installed on the main shaft, a secondary shaft gear meshing with the main shaft gear is installed on the secondary shaft, a ratchet meshing with the main shaft gear is slidably installed on the main shaft gear or / and a ratchet meshing with the secondary shaft is installed on the secondary shaft, and the ratchet is drivingly connected to the shift control system. It can be seen that the shift control mechanism drives the shift control gear set to rotate to achieve shifting, but during riding, the ratchet and the main shaft gear or the secondary shaft gear have a large force, resulting in a shift failure.

[0003] Therefore, the existing technology needs to be improved and developed. Utility Model Content

[0004] The purpose of the present application is to provide a mid-axle transmission, a mid-mounted motor and a vehicle, which have a higher success rate in gear shifting and smoother gear shifting.

[0005] In order to solve the above technical problems, the present application provides a mid-shaft transmission, comprising:

[0006] A transmission mechanism, comprising two or more gear sets, a first transmission shaft and a second transmission shaft, each of the gear sets comprising a pair of mutually meshing gears, the gears of the gear sets being respectively arranged on the first transmission shaft and the second transmission shaft, and the transmission mechanism having at least two transmission ratios;

[0007] an input assembly connected to the first transmission shaft and configured to input torque to the first transmission shaft;

[0008] An output assembly, connected to the gear set, for outputting torque;

[0009] A gear shift mechanism, used for switching the operation of different gear sets to change the transmission ratio of the transmission mechanism;

[0010] A shift assist mechanism, when the shift mechanism is unable to switch between different gear sets, the torque of the second transmission shaft is transmitted to the shift mechanism through the shift assist mechanism to smoothly complete the shift operation.

[0011] Furthermore, a control shaft, the shift assembly is slidably connected to the shift control shaft, and is used to control the reciprocating motion of the shift assembly.

[0012] Further, the shift assembly includes a shift driving member and a shift engaging member, the shift engaging member is rotatably mounted on the shift driving member, and the shift control shaft drives the shift engaging member to engage with or disengage the gear of the gear set.

[0013] Furthermore, the shift control shaft is provided with a control groove, and the control groove of the shift control shaft is configured to decompose the torque in the first rotation direction input to the second transmission shaft into a thrust on the shift assembly to assist the shift engagement member in separating from the gears of the gear set.

[0014] Further, the shift assist mechanism includes a torque input member, a first connecting member, a second connecting member and a third connecting member, the torque input member has a torque in a first rotational direction, the first connecting member and the third connecting member are rotatably supported on the second connecting member, the first connecting member is connected to the third connecting member through a second elastic member, the second elastic member provides a pre-tightening torque, the first connecting member rotates along the first rotational direction, when the torque input to the first connecting member exceeds the pre-tightening torque, the second elastic member is deformed, the first connecting member and the third connecting member generate relative rotation, so that the third connecting member and the torque input member engage to transmit the torque of the torque input member to the third connecting member.

[0015] Further, the third connecting member moves axially along the first rotation direction to engage with the torque input member.

[0016] Further, the third connecting member is provided with an eighth engaging portion, the torque input member is provided with a fifth engaging portion, the eighth engaging portion is arranged opposite to the fifth engaging portion, and the eighth engaging portion of the third connecting member can be engaged with or separated from the fifth engaging portion of the torque input member.

[0017] Further, the first connecting member is provided with a sixth engaging portion, and the third connecting member is provided with a seventh engaging portion, and the sixth engaging portion and the seventh engaging portion are arranged opposite to each other. When the torque input into the first connecting member does not exceed the pre-tightening torque, the sixth engaging portion of the first connecting member remains engaged with the seventh engaging portion of the third connecting member, so that the first connecting member and the third connecting member rotate synchronously, and the second connecting member is sleeved with a third elastic member, and the third elastic member acts on the third connecting member to keep the sixth engaging portion of the first connecting member engaged with the seventh engaging portion of the third connecting member.

[0018] Further, the third connecting member is provided with a connecting groove, the first connecting member is provided with a blocking portion, the blocking portion extends into the connecting groove, and the length of the connecting groove is longer than the length of the blocking portion;

[0019] When the first connecting member rotates along the first rotation direction, the blocking portion abuts against one end of the connecting groove, the sixth engaging portion of the first connecting member is separated from the seventh engaging portion of the third connecting member, and the seventh engaging portion of the third connecting member is pushed to make the third connecting member slide axially along the first rotation direction, so that the third connecting member is engaged with the torque input member;

[0020] When the first connecting member rotates along a second rotation direction opposite to the first rotation direction, the blocking portion abuts against the other end of the connecting groove, the sixth engaging portion of the first connecting member engages with the seventh engaging portion of the third connecting member, and the third connecting member rotates along the second rotation direction following the first connecting member.

[0021] Furthermore, the first connecting member is provided with a first installation groove, a first elastic member is provided in the first installation groove, one end of the first elastic member is connected to the first connecting member, and the other end of the first elastic member is connected to the second connecting member.

[0022] Furthermore, the first connecting member is provided with a second mounting groove on a side opposite to the first mounting groove, the second elastic member is installed in the second mounting groove, one end of the second elastic member is connected to the first connecting member, and the other end of the second elastic member is connected to the third connecting member.

[0023] Furthermore, a spiral wire groove is provided on the outer peripheral surface of the first connecting member.

[0024] Furthermore, gear teeth are provided on the edge of the third connecting member.

[0025] Furthermore, the shift assembly includes a shift driving member and a shift engaging member, the shift engaging member is rotatably mounted on the shift driving member, and the shift control shaft drives the shift engaging member to engage with or disengage the gear of the gear set through a lever transmission.

[0026] Furthermore, the gear shift driving member includes a guide portion and a fork body, the guide portion is slidably connected to the control groove of the gear shift control shaft, and the gear shift engaging member is rotatably mounted on the fork body.

[0027] Furthermore, it also includes a lever mechanism, and the shift control shaft is connected to the shift assembly through the lever mechanism.

[0028] Further, the lever mechanism includes a lever and a second bracket, the lever includes a first end, a second end and a connecting hole, the connecting hole is arranged between the first end and the second end, the second bracket is provided with a movable groove, the second end of the lever can be rotatably installed in the movable groove to form a fulcrum, the shift control shaft is provided with a control groove, the first end of the lever can slide in the control groove, the connecting hole is connected to the shift assembly, and the length from the fulcrum to the first end is greater than the length from the second end to the connecting hole.

[0029] Furthermore, the second bracket is provided with a fixing portion, and a fourth elastic member is provided between the fixing portion and the second end portion, and the fourth elastic member acts on the second end portion so that the second end portion has a movement tendency toward the gear correspondingly engaged with the shift assembly, and the movable groove is a waist-shaped groove, and the second end portion can slide in the movable groove.

[0030] Furthermore, a third bracket is included, and the fork body is hinged on the third bracket at one end away from the guide portion to form a fulcrum, and the length from the guide portion to the fulcrum is greater than the length from the axis of the shift engagement member to the fulcrum.

[0031] Furthermore, a fourth elastic member is provided between the fork body and the third bracket.

[0032] Further, it also includes a lever mechanism, the shift control shaft is connected to the shift assembly through the lever mechanism, the lever mechanism includes a lever and a fourth bracket, the lever includes a first end, a second end and a connecting hole, the connecting hole is arranged between the first end and the second end, the fourth bracket is provided with a movable groove, the second end of the lever is rotatably installed in the movable groove to form a first fulcrum, the shift control shaft is provided with a control groove, the first end of the lever can slide in the control groove, the connecting hole is connected to the shift assembly, and the length from the first fulcrum to the first end is greater than the length from the second end to the connecting hole;

[0033] It also includes a third bracket, and the fork body is hinged on the third bracket at one end away from the guide portion to form a second fulcrum, and the length from the guide portion to the second fulcrum is greater than the length from the axis of the shift engagement member to the second fulcrum.

[0034] Furthermore, it also includes a second bracket, the second bracket is provided with a fixing portion, a fourth elastic member is provided between the fixing portion and the second end portion, the fourth elastic member acts on the first end portion so that the first end portion has a movement tendency toward the corresponding gear engaged with the shift assembly, the movable groove is a waist-shaped groove, and the first end portion can slide in the movable groove.

[0035] Furthermore, the output assembly includes a transmission sleeve and a front sprocket fixed to each other, and the transmission sleeve is connected to the gear set for outputting torque to the front sprocket.

[0036] Furthermore, a sliding portion is provided on the inner circumferential surface of the shift engagement member, and the shift engagement member can be slidably matched with the first transmission shaft, the second transmission shaft and the transmission sleeve.

[0037] Furthermore, it also includes a one-way clutch, which is arranged between the first transmission shaft and / or the second transmission shaft and the gear of the gear group. When the gear group where the one-way clutch is located is working, the one-way clutch is engaged; when the shifting mechanism switches the gear group where the one-way clutch is located to another gear group to work, the one-way clutch is disengaged so that the gear group where the one-way clutch is located does not work.

[0038] Furthermore, the gear set is a speed-increasing transmission, a speed-reducing transmission, or a compound transmission of a speed-increasing transmission and a speed-reducing transmission.

[0039] Furthermore, the speed increasing transmission includes at least two of the gear sets, and the one-way clutch is arranged between the gear with the smallest number of teeth and the first transmission shaft.

[0040] Further, the one-way clutch includes a first one-way clutch, the gear group includes a first gear group and a second gear group, the first gear group includes a first gear and a second gear that are externally meshed with each other, the second gear group includes a third gear and a fourth gear that are externally meshed with each other, the number of teeth of the first gear is smaller than the number of teeth of the third sun gear, the third gear is fixed on the first transmission shaft, the first one-way clutch is installed between the first gear and the first transmission shaft, the second gear is fixedly installed on the second transmission shaft, and the fourth gear is rotatably installed on the second transmission shaft.

[0041] Further, when the first gear set is working, the first one-way clutch is engaged; when the first gear set is switched to the second gear set for working, the first one-way clutch is disengaged to make the first gear set not working.

[0042] Furthermore, the reduction transmission includes at least two of the gear sets, and the one-way clutch is arranged between the gear with the smallest number of teeth and the second transmission shaft.

[0043] Further, the one-way clutch includes a second one-way clutch, the output assembly includes a transmission sleeve and a front sprocket fixed to each other, the transmission sleeve is connected to the gear group for outputting torque to the front sprocket, the gear group includes a third gear group, a fourth gear group and a fifth gear group, the third gear group includes a fifth gear and a sixth gear that are externally meshed with each other, the fourth gear group includes a seventh gear and an eighth gear that are externally meshed with each other, the fifth gear group includes a ninth gear and a tenth gear that are externally meshed with each other, the number of teeth of the sixth gear, the number of teeth of the eighth gear and the number of teeth of the tenth gear decrease successively, the eighth gear is fixedly mounted on the second transmission shaft, the sixth gear is rotatably mounted on the second transmission shaft, the second one-way clutch is mounted between the tenth gear and the second transmission shaft, the transmission sleeve is rotatably mounted on the first transmission shaft, the fifth gear and the ninth gear are fixedly mounted on the transmission sleeve, and the seventh gear is rotatably mounted on the transmission sleeve.

[0044] Further, when the fifth gear set is working, the second one-way clutch is engaged; when the fifth gear set is switched to the third gear set or the fourth gear set is working, the second one-way clutch is disengaged to make the fifth gear set not working.

[0045] Furthermore, the one-way clutch is arranged on one side of the gear.

[0046] Furthermore, the one-way clutch is a roller-type overrunning clutch.

[0047] The present application also provides a mid-mounted motor, including the above-mentioned mid-shaft transmission, and also including a motor, wherein the motor is connected to the first transmission shaft, the second transmission shaft or the transmission sleeve.

[0048] Furthermore, the motor is connected to the first transmission shaft, the second transmission shaft or the transmission sleeve through any one of chain drive, belt drive and gear drive.

[0049] The present application also provides a vehicle, comprising the above-mentioned mid-axle transmission or the above-mentioned mid-mounted motor.

[0050] As can be seen from the above, the mid-axle transmission of the present application is provided with a shift assist mechanism. When the torque generated by the rider operating the control line is insufficient to overcome the force between the shift engaging portion of the shift engaging member and the engaging portion of the gear, that is, the shift mechanism is unable to switch between different gear sets, the torque of the second transmission shaft is transmitted to the shift mechanism through the shift assist mechanism. The torque of the second transmission shaft is the torque generated by the rider's pedaling, which is much greater than the torque generated by the operating control line, and can overcome the force between the shift engaging portion of the shift engaging member and the engaging portion of the gear to smoothly complete the shift operation.

[0051] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a three-dimensional diagram of the mid-shaft transmission of Example 1.

[0053] Figure 2 It is a three-dimensional view of the mid-shaft transmission of Example 1 from another angle.

[0054] Figure 3 It is a top view of the mid-shaft transmission of Example 1 (the outer shell body is hidden).

[0055] Figure 4 This is a bottom view of the mid-shaft transmission of Example 1 (the outer shell body is hidden).

[0056] Figure 5 It is a schematic structural diagram of the transmission mechanism, shift mechanism, and shift assist mechanism of Example 1.

[0057] Figure 6 It is a three-dimensional diagram of the transmission mechanism, the shift mechanism, and the shift assist mechanism of Example 1.

[0058] Figure 7 It is a three-dimensional diagram of the transmission mechanism, the shift mechanism, and the shift auxiliary mechanism of Example 1 from another angle.

[0059] Figure 8 The transmission mechanism and the shift mechanism of embodiment 1 are Figure 7 Center J view.

[0060] Fig. 9 The transmission mechanism and the shift mechanism of embodiment 1 are Figure 8 Middle K-axis view.

[0061] Fig.10 Schematic diagram of the structure of the gear and shift assembly of Example 1.

[0062] Fig.11 It is a three-dimensional diagram of the shift assist mechanism of Example 1.

[0063] Fig.12 It is a three-dimensional diagram of the shift assist mechanism of Example 1 from another angle.

[0064] Fig.13 This is a longitudinal sectional view of the shift assist mechanism of the first embodiment.

[0065] Fig.14This is one of the working state schematic diagrams of the shift assist mechanism of Example 1.

[0066] Fig.15 This is the second schematic diagram of the working state of the shift assist mechanism of Example 1.

[0067] Fig.16 This is the third schematic diagram of the working state of the shift assist mechanism of Example 1.

[0068] Fig.17 This is the first gear power transmission path diagram of the mid-shaft transmission of Example 1.

[0069] Fig.18 This is the second gear power transmission path diagram of the mid-shaft transmission of Example 1.

[0070] Fig.19 This is the third gear power transmission path diagram of the mid-shaft transmission of Example 1.

[0071] Fig. 20 This is the fourth gear power transmission path diagram of the mid-shaft transmission of Example 1.

[0072] Fig.21 This is the fifth gear power transmission path diagram of the mid-shaft transmission of Example 1.

[0073] Fig. 22 This is the sixth gear power transmission path diagram of the mid-shaft transmission of Example 1.

[0074] Fig.23 This is the seventh gear power transmission path diagram of the mid-shaft transmission of Example 1.

[0075] Fig.24 This is a schematic diagram of the structure of the mid-shaft transmission of Example 2.

[0076] Fig.25 Schematic diagram of the structure of the gear and shift assembly of Example 2.

[0077] Fig.26 It is a schematic structural diagram of the mid-shaft transmission of Example 3.

[0078] Fig. 27 Schematic diagram of the structure of the gear and shift assembly of Example 3.

[0079] Description of labels:

[0080] 1-housing, 11-first mounting plate, 12-second mounting plate, 13-housing body, 14-wire tube fixing part,

[0081] 2-input assembly, 21-left crank, 22-right crank,

[0082] 3-output assembly, 31-transmission sleeve, 311-first joint, 32-front sprocket,

[0083] 4- Transmission mechanism,

[0084] 41-first gear set, 411-first gear, 412-second gear,

[0085] 42- second gear set, 421- third gear, 422- fourth gear, 4221- second engagement portion,

[0086] 43-third gear set, 431-fifth gear, 432-sixth gear, 4321-third joint,

[0087] 44- fourth gear set, 441- seventh gear, 4411- fourth joint, 442- eighth gear,

[0088] 45-fifth gear set, 451-ninth gear, 452-tenth gear,

[0089] 46-first transmission shaft, 47-second transmission shaft, 471-fifth engagement portion, 48-first one-way clutch, 49-second one-way clutch,

[0090] 5- Gear shifting mechanism,

[0091] 51-shift assembly, 51A-first shift assembly, 51B-second shift assembly, 51C-third shift assembly, 51D-fourth shift assembly, 511-shift driving member, 5111-guide portion, 5112-shaft sleeve, 5113-fork body, 512-shift engagement member, 5121-shift engagement portion,

[0092] 52-First bracket,

[0093] 53-lever mechanism, 53A-first lever mechanism, 53B-second lever mechanism, 53C-third lever mechanism, 53D-fourth lever mechanism, 531-lever, 5311-first end, 5312-second end, 5313-connecting hole, 532-second bracket, 5321-movable groove, 5321A-first movable groove, 5321B-second movable groove, 5321C-third movable groove, 5321D-fourth movable groove, 5322-fixing portion, 533-fourth elastic member,

[0094] 54-shift control shaft, 541-control slot, 541A-first control slot, 541B-second control slot, 541C-third control slot, 541D-fourth control slot,

[0095] 55-third bracket, 56-fourth bracket,

[0096] 6- Gear shift assist mechanism,

[0097] 61-first connecting member, 611-wire slot, 612-first mounting slot, 613-second mounting slot, 614-sixth joint, 615-blocking portion,

[0098] 62- second connecting member,

[0099] 63-third connecting member, 631-connecting groove, 632-seventh connecting portion, 633-eighth connecting portion, 634-gear teeth,

[0100] 64-first elastic member, 65-second elastic member, 66-third elastic member, 67-fastener,

[0101] 7- linkage mechanism, 71- first linkage member, 72- second linkage member. DETAILED DESCRIPTION

[0102] The embodiments of the present invention are described in detail below, and examples of the embodiments 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 cannot be understood as limiting the present invention.

[0103] In the description of the present utility model, 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 indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model 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 a limitation on the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0104] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0105] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0106] Example 1

[0107] Figure 1 It is a three-dimensional diagram of the middle shaft transmission. Figure 2 The stereoscopic view of the mid-shaft transmission from another angle. The mid-shaft transmission of the present application is fixedly mounted at the bottom of the middle of the vehicle frame, and includes a housing 1, a transmission mechanism 4, an input assembly 2, an output assembly 3, a shift mechanism 5 and a shift assist mechanism 6. The first mounting plate 11 and the second mounting plate 12 are both fixed to the vehicle frame by screws. The housing 1 includes a first mounting plate 11 and a second mounting plate 12, and a cylindrical housing body 13 is fixedly mounted between the first mounting plate 11 and the second mounting plate 12. The transmission mechanism 4, the shift mechanism 5 and the shift assist mechanism 6 are all inside the housing 1, which can avoid being affected by external dust and moisture, and can also avoid impact, thereby extending the service life of the mid-shaft transmission.

[0108] The input assembly 2 includes a left crank 21 and a right crank 22, and pedals are mounted on the two cranks respectively. The torque generated by the rider stepping on the pedals is transmitted to the transmission mechanism 4 through the cranks. The transmission mechanism 4 includes more than two gear sets, and the gears of the gear sets are respectively arranged on the first transmission shaft 46 and the second transmission shaft 47 and mesh with each other. The transmission ratios of the gear sets are different, and the shifting mechanism 5 switches different gear sets to work to change the transmission ratio of the transmission mechanism 4, so the transmission mechanism 4 has at least two transmission ratios.

[0109] The output assembly 3 includes a transmission sleeve 31 and a front sprocket 32. The front sprocket 32 ​​is fixedly mounted on the transmission sleeve 31. Some gears of the gear set are fixed on the transmission sleeve 31. The front sprocket 32 ​​is fixedly mounted on the transmission sleeve 31. The front sprocket 32 ​​is transmitted to the rear front sprocket 32 ​​of the rear wheel through a chain, and the torque is transmitted to the rear wheel to drive the vehicle forward.

[0110] The shift mechanism 5 and the external shift controller are driven by a control line. The rider can operate the shift controller to switch the mid-shaft transmission to a low gear during climbing and to a high gear during descending.

[0111] It should be noted that the front sprocket 32 ​​may also be replaced by a pulley, and the chain may also be replaced by a belt.

[0112] The middle shaft transmission 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.

[0113] Figure 3 It is a top view of the mid-shaft transmission (the housing body 13 is hidden). Figure 4 It is a bottom view of the mid-shaft transmission (the housing body 13 is hidden). Figure 5 It is a schematic structural diagram of the transmission mechanism 4 , the shift mechanism 5 , and the shift assist mechanism 6 (sectioned along the axis of the first transmission shaft 46 and the axis of the second transmission shaft 47 ).

[0114] In this embodiment, the transmission mechanism 4 includes five gear groups, a first transmission shaft 46 and a second transmission shaft 47. The transmission mechanism 4 has five gear groups, and the five gear groups include a first gear group 41, a second gear group 42, a third gear group 43, a fourth gear group 44 and a fifth gear group 45. Specifically, the first gear group 41 includes a first gear 411 and a second gear 412 that are externally meshed with each other, the second gear group 42 includes a third gear 421 and a fourth gear 422 that are externally meshed with each other, the third gear group 43 includes a fifth gear 431 and a sixth gear 432 that are externally meshed with each other, the fourth gear group 44 includes a seventh gear 441 and an eighth gear 442 that are externally meshed with each other, and the fifth gear group 45 includes a ninth gear 451 and a tenth gear 452 that are externally meshed with each other.

[0115] The first gear 411 and the third gear 421 are mounted on the first transmission shaft 46, which is also called the middle shaft. Specifically, the third gear 421 is fixed on the first transmission shaft 46 and rotates with the first transmission shaft 46. A first one-way clutch 48 is installed between the first gear 411 and the first transmission shaft 46. The transmission sleeve 31 is rotatably mounted on the first transmission shaft 46. The transmission sleeve 31 is located on the outside of the first transmission shaft 46. The fifth gear 431, the seventh gear 441, and the ninth gear 451 are mounted on the transmission sleeve 31, wherein the fifth gear 431 and the ninth gear 451 are fixedly mounted on the transmission sleeve 31, and the seventh gear 441 is rotatably mounted on the transmission sleeve 31.

[0116] The second gear 412, the fourth gear 422, the sixth gear 432, the eighth gear 442 and the tenth gear 452 are installed on the second transmission shaft 47. Specifically, the second gear 412 and the eighth gear 442 are fixedly installed on the second transmission shaft 47, the fourth gear 422 and the sixth gear 432 are rotatably installed on the second transmission shaft 47, and a second one-way clutch 49 is installed between the tenth gear 452 and the second transmission shaft 47.

[0117] The first transmission shaft 46 and the second transmission shaft 47 are both hollow shafts, which can reduce the weight of the entire mid-shaft transmission.

[0118] Depend on Figure 5 It can be seen that the number of teeth of the first gear 411 is greater than the number of teeth of the second gear 412, and the number of teeth of the third gear 421 is greater than the number of teeth of the fourth gear 422. According to the calculation formula of the transmission ratio, the transmission ratio = the number of teeth of the driven gear divided by the number of teeth of the driving gear. Since the first transmission shaft 46 is the driving shaft relative to the second transmission shaft 47 and the second transmission shaft 47 is the driven shaft, the first gear 411 and the third gear 421 are installed on the first transmission shaft 46 and are driving gears. The second gear 412 and the fourth gear 422 are installed on the second transmission shaft 47 and are driven gears. Therefore, the transmission ratios of the first gear set 41 and the second gear set 42 are both less than 1, which is a speed-increasing transmission.

[0119] Similarly, with respect to the transmission sleeve 31, the second transmission shaft 47 is the driving shaft, and the transmission sleeve 31 is the driven shaft. Then the sixth gear 432, the eighth gear 442, and the tenth gear 452 installed on the second transmission shaft 47 are driving gears, and the fifth gear 431, the seventh gear 441, and the ninth gear 451 are driven gears. The number of teeth of the fifth gear 431 is less than that of the sixth gear 432, so the transmission ratio of the third gear set 43 is less than 1, which is a speed-increasing transmission. The number of teeth of the seventh gear 441 is greater than that of the eighth gear 442, so the transmission ratio of the fourth gear set 44 is less than 1, which is a speed-reducing transmission. The number of teeth of the ninth gear 451 is greater than that of the tenth gear 452, so the transmission ratio of the fifth gear set 45 is greater than 1, which is a speed-reducing transmission.

[0120] Only one of the first gear set 41 and the second gear set 42 can work, and only one of the third gear set 43, the fourth gear set 44 and the fifth gear set 45 can work, otherwise the first transmission shaft 46 and the second transmission shaft 47 will not be able to rotate. Therefore, the first gear set 41 can be matched with any one of the third gear set 43, the fourth gear set 44 and the fifth gear set 45 to obtain three different transmission ratios, and the second gear set 42 can be matched with any one of the third gear set 43, the fourth gear set 44 and the fifth gear set 45 to obtain another three different transmission ratios, that is, there are six gears in total.

[0121] In addition, the transmission mechanism 4 also has a gear position without changing the speed through the gear set, and the gear position with a transmission ratio of 1 is obtained by directly connecting the first transmission shaft 46 and the transmission sleeve 31 through the shift mechanism 5.

[0122] Figure 6 It is a three-dimensional diagram of the transmission mechanism 4 , the shift mechanism 5 , and the shift assist mechanism 6 . Figure 7 It is a three-dimensional diagram of the transmission mechanism 4, the shift mechanism 5, and the shift auxiliary mechanism 6 from another angle. Figure 8 The transmission mechanism 4 and the shift mechanism 5 are Figure 7 Center J view. Fig. 9 The transmission mechanism 4 and the shift mechanism 5 are Figure 8View in the direction of K. As shown in the figure, the shift mechanism 5 includes a shift assembly 51 and a shift control shaft 54. The shift assembly 51 is provided with four groups, including a first shift assembly 51A, a second shift assembly 51B, a third shift assembly 51C and a fourth shift assembly 51D, wherein the first shift assembly 51A corresponds to controlling the separation and engagement of the fourth gear 422 and the second transmission shaft 47, the second shift assembly 51B corresponds to controlling the separation and engagement of the transmission sleeve 31 and the first transmission shaft 46, the third shift assembly 51C corresponds to controlling the separation and engagement of the seventh gear 441 and the transmission sleeve 31, and the fourth shift assembly 51D corresponds to controlling the separation and engagement of the sixth gear 432 and the transmission sleeve 31. The four shift assemblies 51 have basically the same structure. The shift assembly 51 is slidably connected to the shift control shaft 54 ​​to control the reciprocating motion of the shift assembly 51.

[0123] The shift control shaft 54 ​​may be directly connected to the shift assembly 51 or indirectly connected to the shift assembly 51 .

[0124] In order to better switch the operation of different gear sets, the shift control shaft 54 ​​drives the shift engagement member 512 to engage or disengage the gears of the gear set through a lever transmission. Lever transmission is divided into three types: labor-saving lever, labor-intensive lever and equal-arm lever. The lever transmission of the present application can adopt the labor-saving lever.

[0125] Fig.10 Schematic diagram of the structure of the gear and the shift assembly 51. The shift assembly 51 includes a shift driver 511 and a shift engagement member 512, and the shift engagement member 512 is rotatably mounted on the shift driver 511. In this embodiment, the shift driver 511 includes a guide portion 5111, a sleeve 5112 and a fork body 5113 arranged from top to bottom. The guide portion 5111 is a cylindrical protrusion, which is used to be inserted into the control groove 541 of the shift control shaft 54. The sleeve 5112 is a cylindrical structure, which is slidably matched with the first bracket 52. The first bracket 52 is a cylinder, and its two ends are fixed on the first mounting plate 11 and the second mounting plate 12. The axis of the first bracket 52, the axis of the first transmission shaft 46, and the axis of the second transmission shaft 47 are parallel to each other. The sleeve 5112 cooperates with the first bracket 52 to realize the reciprocating linear motion of the shift driver 511 along the axial direction of the first bracket 52. The fork body 5113 is Y-shaped, and the shift engaging member 512 is rotatably mounted on the fork body 5113 .

[0126] The shift coupling member 512 is a cylindrical structure, and a sliding portion is provided on the inner circumferential surface of the shift coupling member 512. The sliding portion is correspondingly provided on the outer circumferential surface of the first transmission shaft 46, and the sliding portion of the first transmission shaft 46 is slidably connected with the sliding portion of the shift coupling member 512 of the second shift assembly 51B. The sliding portion is correspondingly provided on the outer circumferential surface of the second transmission shaft 47, and the sliding portion of the second transmission shaft 47 is slidably connected with the sliding portion of the shift coupling member 512 of the first shift assembly 51A and the sliding portion of the shift coupling member 512 of the fourth shift assembly 51D respectively. The sliding portion is correspondingly provided on the outer circumferential surface of the transmission sleeve 31, and the sliding portion of the transmission sleeve 31 is slidably connected with the sliding portion of the shift coupling member 512 of the third shift assembly 51C.

[0127] The sliding portion can be any structure that can slide along the axial direction. In the present embodiment, in order to transmit a larger torque and smooth sliding, the sliding portion adopts a sliding spline transmission method, that is, if the sliding portion of the outer peripheral surface of the first transmission shaft 46 is a spline, then the sliding portion of the shift coupling member 512 of the second shift assembly 51B is a spline groove, and the same applies to other shift coupling members 512.

[0128] A shift engagement portion 5121 is provided on one side of the shift engagement member 512, and engagement portions are correspondingly provided on the gears and the transmission sleeve 31, that is, a second engagement portion 4221 is provided on the fourth gear 422, a third engagement portion 4321 is provided on the sixth gear 432, a fourth engagement portion 4411 is provided on the seventh gear 441, and a first engagement portion 311 is provided on the transmission sleeve 31.

[0129] The shift control shaft 54 ​​drives the shift engagement member 512 to engage or disengage with the gear of the gear set. To facilitate engagement or disengagement, the shift engagement portion 5121 of the shift engagement member 512 is positioned opposite to the engagement portion of the gear or the transmission sleeve 31 .

[0130] Taking the seventh gear 441 as an example, when the shift driving member 511 drives the shift engaging member 512 to approach the seventh gear 441, the shift engaging portion 5121 of the shift engaging member 512 engages with the fourth engaging portion 4411 of the seventh gear 441. After engagement, the shift engaging portion 5121 and the seventh gear 441 rotate synchronously to transmit torque; when the shift driving member 511 drives the shift engaging member 512 away from the seventh gear 441, the shift engaging portion 5121 of the shift engaging member 512 is separated from the fourth engaging portion 4411 of the seventh gear 441. After separation, the shift engaging portion 5121 rotates with the second transmission shaft 47, and the seventh gear 441 is rotatable relative to the second transmission shaft 47, and the torque of the second transmission shaft 47 cannot be transmitted to the seventh gear 441 through the shift engaging portion 5121.

[0131] The shift engagement portion 5121 and the engagement portion may be ratchets arranged along the circumferential direction, the tooth shape of the ratchets is an oblique trapezoid, the ratchets can only transmit unidirectional torque, are suitable for higher speeds and loads, and can be engaged or disengaged in a stationary state or when the speed difference is small.

[0132] In order to control the movement of the shift assembly 51, in the present embodiment, a shift control shaft 54 ​​is used. Of course, the shift control shaft 54 ​​can be replaced by any device capable of realizing reciprocating linear motion, such as a cylinder, a hydraulic cylinder, a worm gear mechanism, or the like.

[0133] The shift control shaft 54 ​​is a round rod, and its axis is parallel to the axis of the first transmission shaft 46 and the axis of the second transmission shaft 47. The two ends of the shift control shaft 54 ​​are supported by the first mounting plate 11 and the second mounting plate 12 respectively. The shift control shaft 54 ​​can be driven to rotate by the shift assist mechanism 6.

[0134] The outer peripheral surface of the shift control shaft 54 ​​is provided with control grooves 541 of equal width. The control grooves 541 are used to control the shift assembly 51 to regularly engage or disengage the shift coupling member 512 with the gear in a gear sequence. Since four shift assemblies 51 are provided, four control grooves 541 are provided accordingly, namely the first control groove 541A, the second control groove 541B, the third control groove 541C and the fourth control groove 541D. The first control groove 541A corresponds to controlling the first shift assembly 51A, the second control groove 541B corresponds to controlling the second shift assembly 51B, the third control groove 541C corresponds to controlling the third shift assembly 51C, and the fourth control groove 541D corresponds to controlling the fourth shift assembly 51D.

[0135] The control groove 541 of the shift control shaft 54 ​​is configured to decompose the torque of the first rotation direction input to the second transmission shaft 47 into a thrust to the shift assembly 51, so as to assist the shift engagement member 512 in separating from the gear of the gear set. In the present application, the control groove 541 has at least one V-shaped groove, and the ends thereof are connected by grooves in the circumferential direction, and is opened along the radial direction of the shift control shaft 54. The V-shaped control groove 541 can decompose the torque of the input shift control shaft 54 ​​into a thrust to the shift assembly 51 during the rotation process.

[0136] During the engagement process, there will not be much force between the engagement parts of the shift engagement part 5121 of the shift engagement member 512 and the engagement part of the gear, that is, the ratchets are slowly engaged; conversely, during the separation process, the shift engagement part 5121 of the shift engagement member 512 and the engagement part of the gear or the transmission sleeve 31, the shift engagement member 512, the gear or the transmission sleeve 31 are all rotating at high speed and carrying load, and there will be a large force between the engagement parts of the two, resulting in difficulty in separation, and then causing gear shifting failure.

[0137] In order to solve the above problem, the shift mechanism 5 further includes a lever mechanism 53 , and the shift control shaft 54 ​​is connected to the shift assembly 51 through the lever mechanism 53 .

[0138] Four lever mechanisms 53 are provided, namely the first lever mechanism 53A, the second lever mechanism 53B, the third lever mechanism 53C and the fourth lever mechanism 53D. One end of the first lever mechanism 53A is connected to the first control groove 541A, and the other end is connected to the first gear shift assembly 51A; one end of the second lever mechanism 53B is connected to the second control groove 541B, and the other end is connected to the second gear shift assembly 51B; one end of the third lever mechanism 53C is connected to the third control groove 541C, and the other end is connected to the third gear shift assembly 51C; one end of the fourth lever mechanism 53D is connected to the fourth control groove 541D, and the other end is connected to the fourth gear shift assembly 51D.

[0139] Each lever mechanism 53 includes a lever 531 and a second bracket 532. The lever 531 is in the shape of a long rod and is perpendicular to the axial direction of the shift control shaft 54. The lever 531 includes a first end 5311 and a second end 5312. The first end 5311 is a structure protruding outward along the length direction of the lever 531. The width of the first end 5311 is slightly smaller than the width of the control groove 541. The side wall of the first end 5311 forms a sliding pair with the side wall of the control groove 541. The first end 5311 is inserted into the control groove 541 of the shift control shaft 54 ​​and can slide in the control groove 541.

[0140] The second end portion 5312 is movably connected to the second bracket 532. The second bracket 532 is a thin plate, and its two ends are respectively fixed to the first mounting plate 11 and the second mounting plate 12. The second end portion 5312 has a cylindrical protrusion perpendicular to the end face of the second bracket 532. The second bracket 532 is also provided with a movable groove 5321. The second end portion 5312 is inserted into the movable groove 5321 and extends out from the bottom of the second bracket 532. The movable groove 5321 can be a circular hole with a diameter slightly larger than the second end portion 5312. The second end portion 5312 can rotate relative to the movable groove 5321, and the rotation point is the fulcrum.

[0141] A connecting hole 5313 is provided between the first end 5311 and the second end 5312, and the guide portion 5111 of the shift driving member 511 is inserted into the connecting hole 5313. When the shift control shaft 54 ​​is driven to rotate by the shift assisting mechanism 6, the first end 5311 of the lever 531 is pushed in the control groove 541, and reciprocates along the axial direction of the first bracket 52 with the second end 5312 of the lever 531 as a fulcrum. The length from the second end 5312 to the connection hole 5313 is the resistance arm, the length from the second end 5312 (fulcrum) to the first end 5311 is the power arm, the length from the fulcrum to the first end 5311 is greater than the length from the second end 5312 to the connection hole 5313, and the power arm is about twice the resistance arm, so the force of the shift control shaft 54 ​​acting on the first end 5311 of the lever 531, which is converted to the force of the connection hole 5313 of the lever 531 on the shift driving member 511, is about twice the former, so the lever mechanism 53 can help the shift engagement portion 5121 of the shift engagement member 512 to better engage or disengage with the engagement portion of the gear or the transmission sleeve 31. The mid-shaft transmission provided with the lever mechanism 53 has a higher success rate of shifting and a smoother shifting.

[0142] During the engagement process, the shift engagement portion 5121 of the shift engagement member 512 and the engagement portion of the gear may not be fully engaged (insufficient engagement depth), and the rider may experience setbacks or wear of parts during riding, resulting in a poor riding experience. In order to solve the above problems, a fixing portion 5322 is provided on the second bracket 532, and the fixing portion 5322 is a cylindrical protrusion perpendicular to the end face of the second bracket 532, and has the same direction as the protrusion of the second end portion 5312. A fourth elastic member 533 is provided between the fixing portion 5322 and the second end portion 5312, and the fourth elastic member 533 acts on the second end portion 5312 to make the second end portion 5312 have a movement tendency toward the gear corresponding to the engaged gear of the shift assembly 51, that is, the role of the fourth elastic member 533 is to provide an elastic force to keep the shift engagement portion 5121 of the shift engagement member 512 engaged with the engagement portion of the gear. In this embodiment, the fourth elastic member 533 is a tension spring, so the elastic force provided is a tensile force. In order to allow the second end portion 5312 to have a certain amount of movement space in the movable groove 5321 , the movable groove 5321 is configured as a waist-shaped groove, and the second end portion 5312 can slide in the movable groove 5321 .

[0143] The movable groove 5321 includes a first movable groove 5321A, a second movable groove 5321B, a third movable groove 5321C and a fourth movable groove 5321D. Taking the third lever mechanism 53C as an example, in combination with Fig. 9 As shown, the fixed portion 5322 is disposed on the left side of the second end portion 5312 of the lever 531 of the third shift assembly 53C, and the third movable groove 5321C is located on the left side of the fixed portion 5322. The positions of the fixed portion 5322 and the movable groove 5321 of the other lever mechanisms 53 are as shown in FIG. Fig. 9 shown.

[0144] In this embodiment, the fourth elastic member 533 is a tension spring. After being assembled, the fourth elastic member 533 has a certain preload force and has a tendency to pull the second end 5312 of the lever 531 toward the fixed portion 5322. When the control slot 541 rotates to a specific angle, the third shift assembly 51C approaches the seventh gear 441 and begins to engage and the fourth elastic member 533 releases its elastic force. If the two are not properly engaged at the beginning, they will gradually engage in place under the action of the fourth elastic member 533. In this way, the engaging portions of the two will not collide with each other, or they will not separate due to insufficient engagement depth, thereby avoiding setbacks or wear of parts and bringing a better experience to the rider.

[0145] Even with the lever mechanism 53, the gear set may not be able to separate normally in a high speed or high torque environment, such as when the rider is riding at high speed or climbing a hill, and the engagement force exceeds the torque that the shift control shaft 54 ​​can provide, resulting in a shift failure.

[0146] In order to further improve the success rate of gear shifting, a gear shift assist mechanism 6 is provided. When the gear shift mechanism 5 cannot switch to different gear sets, the torque of the second transmission shaft 47 is transmitted to the gear shift mechanism 5 through the gear shift assist mechanism 6 to smoothly complete the gear shift operation.

[0147] Fig.11 It is a perspective view of the shift assist mechanism 6 . Fig.12 It is a three-dimensional view of the shift assist mechanism 6 from another angle. Fig.13 is a longitudinal sectional view of the shift assist mechanism 6. The shift assist mechanism 6 comprises a torque input member, a first connecting member 61, a second connecting member 62, and a third connecting member 63. In this embodiment, the torque input member is the second transmission shaft 47, and the torque input member has a torque in the first rotation direction D1.

[0148] The first connecting member 61 is a rotating member, and a spiral wire groove 611 is provided on its outer circumference. The control wire is led out from the shift controller, and the control wire passes through a wire tube for protecting the control wire and is connected to the first connecting member 61. The control wire is wound along the wire groove 611, and one end is fixed to the outer circumference of the first connecting member 61. The shift controller can retract or release the control wire in sections, and the stroke of each retracting or releasing the control wire is about 6 mm, and each retracting or releasing performs a shift operation.

[0149] The first connecting member 61 is provided with a first mounting groove 612, and a first elastic member 64 is provided in the first mounting groove 612. One end of the first elastic member 64 is connected to the first connecting member 61, and the other end of the first elastic member 64 is connected to the second connecting member 62. The first elastic member 64 can be a spiral spring, which has a compact structure and occupies a small space. The function of the first elastic member 64 is that when the control line is retracted to rotate the first connecting member 61, the first elastic member 64 stores elastic force; when the control line is released, the first elastic member 64 releases the elastic force to make the first connecting member 61 rotate in the opposite direction.

[0150] A wire tube fixing member 14 is installed outside the first connecting member 61 . The wire tube fixing member 14 is fixed to the first mounting plate 11 by screws. A circular hole is formed on the outer peripheral surface of the wire tube fixing member 14 , and the wire tube is inserted into the circular hole.

[0151] The first connecting member 61 is provided with a second mounting groove 613 on a side opposite to the first mounting groove 612, and the second elastic member 65 is installed in the second mounting groove 613, one end of the second elastic member 65 is connected to the first connecting member 61, and the other end of the second elastic member 65 is connected to the third connecting member 63. The second elastic member 65 can be a torsion spring. The first connecting member 61 is provided with a sixth engaging portion 614, which is also located in the second mounting groove 613.

[0152] The second connecting member 62 is a cylindrical structure, one end of which is provided with an internal thread, and the fastener 67 fixes the wire tube fixing member 14 and the second connecting member 62, and the other end of the second connecting member 62 is provided with a flange, which is used to abut the third connecting member 63. The first connecting member 61 and the third connecting member 63 can rotate around the second connecting member 62.

[0153] The third connecting member 63 is provided with a seventh engaging portion 632 on a side close to the sixth engaging portion 614 of the first connecting member 61. When the torque inputted by the first connecting member 61 does not exceed the pre-tightening torque, the sixth engaging portion 614 of the first connecting member 61 remains engaged with the seventh engaging portion 632 of the third connecting member 63, so that the first connecting member 61 and the third connecting member 63 rotate synchronously. When the torque inputted by the first connecting member 61 exceeds the pre-tightening torque, the second elastic member 65 is deformed, and the first connecting member 61 and the third connecting member 63 rotate relative to each other, so that the third connecting member 63 and the torque input member are engaged to transmit the torque of the torque input member to the third connecting member 63. In order to engage the third connecting member 63 and the torque input member, the third connecting member 63 is provided with an eighth engaging portion 633 on a side opposite to the seventh engaging portion 632. The torque input member, i.e., the second transmission member, is provided with a fifth engaging portion 471. After the third connecting member 63 and the torque input member are engaged, the torque of the torque input member can be transmitted to the third connecting member 63.

[0154] In order to keep the sixth engaging portion 614 of the first connecting member 61 engaged with the seventh engaging portion 632 of the third connecting member 63, and to promptly reset the first connecting member 61 and the third connecting member 63 after relative rotation, a third elastic member 66 is sleeved on the second connecting member 62, and the third elastic member 66 acts on the third connecting member 63, that is, the third connecting member 63 abuts against one end of the third elastic member 66, and the other end of the third elastic member 66 abuts against the flange of the second connecting member 62.

[0155] The first connecting member 61 is provided with a second mounting groove 613 on a side opposite to the first mounting groove 612, and a second elastic member 65 is provided in the second mounting groove 613, one end of the second elastic member 65 is connected to the first connecting member 61, and the other end of the second elastic member 65 is connected to the third connecting member 63. The second elastic member 65 may be a torsion spring. The function of the second elastic member 65 is to provide a pre-tightening torque. When the torque input to the first connecting member 61 does not exceed the pre-tightening torque, the sixth engaging portion 614 of the first connecting member 61 remains engaged with the seventh engaging portion 632 of the third connecting member 63, so that the first connecting member 61 and the third connecting member 63 rotate synchronously.

[0156] The first connecting member 61 and the third connecting member 63 are rotatably supported on the second connecting member 62. The first connecting member 61 is connected to the third connecting member 63 through the second elastic member 65. The second elastic member 65 provides a pre-tightening torque. The first connecting member 61 rotates along the first rotation direction D1. The torque input to the first connecting member 61 exceeds the pre-tightening torque, the second elastic member 65 is deformed, and the first connecting member 61 and the third connecting member 63 generate relative rotation, so that the third connecting member 63 and the torque input member engage to transmit the torque of the torque input member to the third connecting member 63.

[0157] The third connecting member 63 is provided with a connecting groove 631, which is an arc-shaped groove and is symmetrically arranged with two thereof. The first connecting member 61 is provided with a blocking portion 615, which is an arc-shaped protrusion. The thickness of the blocking portion 615 is greater than the thickness of the connecting groove 631. The blocking portion 615 extends into the connecting groove 631, and the length of the connecting groove 631 is longer than the length of the blocking portion 615.

[0158] like Fig.15 and Fig.16 As shown, when the first connecting member 61 rotates along the first rotation direction D1, the blocking portion 615 abuts against one end of the connecting groove 631, the sixth engaging portion 614 of the first connecting member 61 is separated from the seventh engaging portion 632 of the third connecting member 63, and the seventh engaging portion 632 of the third connecting member 63 is pushed to make the third connecting member 63 slide axially along the first rotation direction D1, so that the third connecting member 63 moves axially along the first rotation direction D1 to engage with the torque input member.

[0159] like Fig.14As shown, when the first connecting member 61 rotates along the second rotation direction D2 opposite to the first rotation direction, the blocking portion 615 abuts against the other end of the connecting groove 631, the sixth engaging portion 614 of the first connecting member 61 engages with the seventh engaging portion 632 of the third connecting member 63, and the third connecting member 63 follows the first connecting member 61 to rotate along the second rotation direction D2.

[0160] As can be seen from the above, a shift assist mechanism 6 is provided. When the torque generated by the rider operating the control line is insufficient to overcome the force of the engaging portion 5121 of the shift engaging member 512 and the gear, that is, the shift mechanism 5 cannot switch between different gear sets, the torque of the second transmission shaft 47 is transmitted to the shift mechanism 5 through the shift assist mechanism 6. The torque of the second transmission shaft 47 is the torque generated by the rider's pedaling, which is much larger than the torque generated by the operating control line, and can overcome the force of the engaging portion 5121 of the shift engaging member 512 and the gear, so as to smoothly complete the shift operation.

[0161] In order to connect the shift assist mechanism 6 to the shift mechanism 5 , the shift assist mechanism 6 can directly transmit the torque to the shift mechanism 5 through gear transmission, friction wheel transmission or other transmission methods.

[0162] In the present embodiment, since the stroke of the control line is small during each gear shifting process, the angle of rotation of the first connecting member 61 is also small, and therefore a linkage mechanism 7 is provided between the gear shift assist mechanism 6 and the gear shift mechanism 5. The linkage mechanism 7 can be a speed-increasing transmission. In the present embodiment, the gear shift assist mechanism 6 transmits the torque to the gear shift mechanism 5 by means of gear transmission, that is, gear teeth 634 are provided on the edge of the third connecting member 63. The linkage mechanism 7 includes a first linkage member 71 and a second linkage member 72, wherein the first linkage member 71 is a gear with a larger number of teeth than the second linkage member 72, and the gear teeth 634 of the third connecting member 63 are meshed with the first linkage member 71 and the second linkage member 72 in sequence. The first linkage member 71 is an idler gear and only plays a role in reversing. The second linkage member 72 is fixedly connected to the gear shift control shaft 54 ​​of the gear shift mechanism 5. When the rotation angle of the first transmission member is N degrees, the gear shift control shaft 54 ​​can rotate at a rotation angle of kN degrees and in the same direction as the rotation of the first transmission member, where k is greater than 1.

[0163] In addition, the mid-shaft transmission is also equipped with a one-way clutch, which is a mechanical device used to control the direction of torque transmission. It allows power to be transmitted only in one direction and not in the other. When the input shaft rotates, the one-way clutch allows the output shaft to rotate freely. However, when the input shaft stops or rotates in the opposite direction, the one-way clutch prevents the output shaft from rotating.

[0164] The one-way clutch includes the first one-way clutch 48 and the second one-way clutch 49, which can be any structure with a clutch function. The clutch structure can be divided into an operating type (such as a mechanical type, an electromagnetic type, a hydraulic type, a pneumatic type) and an automatic control type (such as an overrunning type, a centrifugal type, a safety type) according to the process of the clutch action. The operating type includes a dog clutch, a gear clutch, etc., and the automatic control type includes a roller clutch, a wedge clutch, etc. In this embodiment, the first one-way clutch 48 and the second one-way clutch 49 use an automatic control roller overrunning clutch. The first one-way clutch 48 and the second one-way clutch 49 have the same structure.

[0165] The basic structure of a roller overrunning clutch usually includes the following parts: an outer ring, which is the fixed part of the clutch and is usually connected to the driven shaft; an inner ring, which is the rotating part of the clutch and is usually connected to the drive shaft; rollers, which are located between the outer ring and the inner ring and can roll freely in the grooves of the inner ring; and a retaining ring, which is used to fix the rollers and prevent them from slipping out of the outer ring.

[0166] The one-way clutch is arranged between the first transmission shaft 46 and / or the second transmission shaft 47 and the gears of the gear set. When the gear set where the one-way clutch is located is working, the one-way clutch is engaged; when the shifting mechanism 5 switches the gear set where the one-way clutch is located to another gear set to work, the one-way clutch is disengaged so that the gear set where the one-way clutch is located does not work.

[0167] The speed-increasing transmission includes at least two gear sets, and the one-way clutch is arranged between the gear with the smallest number of teeth and the first transmission shaft 46. Specifically, the first gear set 41 and the second gear set 42 are both speed-increasing transmissions, and the first one-way clutch 48 is arranged between the first gear 411 with the smallest number of teeth between the first gear 411 and the third gear 421 and the first transmission shaft 46; the speed-reducing transmission includes at least two gear sets, and the one-way clutch is arranged between the gear with the smallest number of teeth and the second transmission shaft 47. Specifically, the fourth gear set 44 and the fifth gear set 45 are both speed-reducing transmissions, and the second one-way clutch 49 is arranged between the tenth gear 452 with the smallest number of teeth between the eighth gear 442 and the tenth gear 452 and the second transmission shaft 47.

[0168] The working process of the one-way clutch is as follows:

[0169] Assume that the number of teeth of the first gear 411 is z1, the rotation speed of the first gear 411 is nx, the number of teeth of the second gear 412 is z2, the number of teeth of the third gear 421 is z3, the number of teeth of the fourth gear 422 is z4, and the rotation speed of the first transmission shaft 46 is constant at n1.

[0170] When the first gear set 41 is working, the speed of the inner ring of the first one-way clutch 48 is always higher than the speed of the outer ring, and the first one-way clutch 48 is engaged.

[0171] When the first gear set 41 switches to the second gear set 42, the rotation speed of the second transmission shaft 47 is n2=z3×n1 / z4. According to the transmission ratio calculation formula of the first gear set 41, i1=z2 / z1=n2 / nx. Substituting n2 into the formula, we can get nx=z3 / z4×z1 / z2×n1. Since the number of teeth z3 of the third gear 421 is greater than the number of teeth z4 of the fourth gear 422, and the number of teeth z1 of the first gear 411 is greater than the number of teeth z2 of the second gear 412, the rotation speed nx of the first gear 411 is greater than the rotation speed n1 of the first transmission shaft 46, that is, the outer ring speed of the first one-way clutch 48 is higher than the inner ring speed, the first one-way clutch 48 is disengaged, and the first gear set 41 does not work.

[0172] It can be seen that if there is no first one-way clutch 48, the first gear set 41 also needs to be provided with a separate shift assembly 51 to control its engagement or disengagement. After the first one-way clutch 48 is provided, when switching from the first gear set 41 to the second gear set 42, only one shift assembly 51 needs to be controlled.

[0173] Similarly, assuming that the number of teeth of the fifth gear 431 is z5, the number of teeth of the sixth gear 432 is z6, the number of teeth of the seventh gear 441 is z7, the number of teeth of the eighth gear 442 is z8, the number of teeth of the ninth gear 451 is z9, the number of teeth of the tenth gear 452 is z10, the rotational speed of the tenth gear 452 is ny, the rotational speed of the second transmission shaft 47 is constant at n2, and the rotational speed of the transmission sleeve 31 is n3.

[0174] When the fifth gear set 45 is working, the speed of the inner ring of the second one-way clutch 49 is always higher than the speed of the outer ring, and the second one-way clutch 49 is engaged.

[0175] When the fifth gear set 45 switches to the fourth gear set 44 for operation, the rotational speed n3 of the transmission sleeve 31 is n3=z8×n2 / z7. According to the transmission ratio calculation formula of the tenth gear set 452, i10=z10 / z9=n3 / ny. Substituting n3 into the formula, we can get ny=z8 / z10×z9 / z7×n2. Since the number of teeth z8 of the eighth gear 442 is greater than the number of teeth z10 of the tenth gear 452, and the number of teeth z9 of the ninth gear 451 is greater than the number of teeth z7 of the seventh gear 441, the rotational speed ny of the tenth gear 452 is greater than the rotational speed n2 of the second transmission shaft 47, that is, the outer ring speed of the second one-way clutch 49 is higher than the inner ring speed, the second one-way clutch 49 is disengaged, and the fifth gear set 45 does not work.

[0176] When the fifth gear set 45 switches to the third gear set 43 for operation, the rotational speed n3 of the transmission sleeve 31 is n3=z6×n2 / z5. According to the transmission ratio calculation formula of the tenth gear set 452, i10=z10 / z9=n3 / ny. Substituting n3 into the formula, we can get ny=z6 / z10×z9 / z5×n2. Since the number of teeth z6 of the sixth gear 432 is greater than the number of teeth z10 of the tenth gear 452, and the number of teeth z9 of the ninth gear 451 is greater than the number of teeth z5 of the fifth gear 431, the rotational speed ny of the tenth gear 452 is greater than the rotational speed n2 of the second transmission shaft 47, that is, the outer ring speed of the second one-way clutch 49 is higher than the inner ring speed, the second one-way clutch 49 is disengaged, and the fifth gear set 45 does not work.

[0177] It can be seen that if there is no second one-way clutch 49, the fifth gear set 45 also needs to be provided with a separate shift assembly 51 to control its engagement or disengagement. After the second one-way clutch 49 is provided, when switching from the fifth gear set 45 to the third gear set 43 or the fourth gear set 44, only two shift assemblies 51 need to be controlled.

[0178] In summary, the mid-axle transmission is provided with two one-way clutches, which respectively replace the two shift assemblies 51. Three shift assemblies 51 can be used to control five gear sets, which simplifies the structure of the shift mechanism 5 and makes it easy to control, while greatly reducing the weight and volume of the mid-axle transmission.

[0179] In order to further reduce the volume of the gear set, the one-way clutch is arranged on one side of the gear. Compared with the one-way clutch being arranged on the inner side of the gear, the radial dimension occupied by the gear is smaller.

[0180] Fig.17 This is the power transmission path diagram for the first gear of the mid-shaft transmission.

[0181] The shift coupling member 512 of the second shift assembly 51B is engaged with the transmission sleeve 31, and the torque is output to the front sprocket 32 ​​after passing through the first transmission shaft 46, the shift coupling member 512 of the second shift assembly 51B, and the transmission sleeve 31 in sequence. At this time, the gear ratio is 1 without changing speed through the gear set.

[0182] Fig.18 This is the power transmission path diagram for the second gear of the mid-shaft transmission.

[0183] All the shifting components 51 are not engaged with the gears or the transmission sleeve 31, the first one-way clutch 48 and the second one-way clutch 49 are in the engaged state, the first gear set 41 and the fifth gear set 45 are working, and the torque is output to the front sprocket 32 ​​after passing through the first transmission shaft 46, the first one-way clutch 48, the first gear 411, the second gear 412, the second transmission shaft 47, the second one-way clutch 49, the tenth gear 452, the ninth gear 451, and the transmission sleeve 31 in sequence. The gear set is a compound transmission that first increases the speed and then decreases the speed.

[0184] Fig.19 This is the power transmission path diagram for the third gear of the mid-shaft transmission.

[0185] The shift engaging member 512 of the third shift assembly 51C is engaged with the seventh gear 441, the first one-way clutch 48 is in an engaged state, the second one-way clutch 49 is in a disengaged state, the first gear set 41 and the fourth gear set 44 are working, and the torque passes through the first transmission shaft 46, the first one-way clutch 48, the first gear 411, the second gear 412, the second transmission shaft 47, the eighth gear 442, the seventh gear 441, the shift engaging member 512 of the third shift assembly 51C, and the transmission sleeve 31 in sequence, and is then output to the front sprocket 32. The gear set is a compound transmission that first increases the speed and then decreases the speed.

[0186] Fig. 20 This is the fourth gear power transmission path diagram of the mid-shaft transmission.

[0187] The shift coupling member 512 of the fourth shift assembly 51D is engaged with the sixth gear 432, the first one-way clutch 48 is in an engaged state, the second one-way clutch 49 is in a disengaged state, the first gear set 41 and the third gear set 43 are working, and the torque passes through the first transmission shaft 46, the first one-way clutch 48, the first gear 411, the second gear 412, the second transmission shaft 47, the shift coupling member 512 of the fourth shift assembly 51D, the sixth gear 432, the fifth gear 431, and the transmission sleeve 31 in sequence, and is output to the front sprocket 32. The gear set is a compound transmission of first speed-increasing transmission and then speed-increasing transmission.

[0188] Fig.21 This is the fifth gear power transmission path diagram of the mid-shaft transmission.

[0189] The shift engaging member 512 of the first shift assembly 51A is engaged with the fourth gear 422, the first one-way clutch 48 is in a disengaged state, the second one-way clutch 49 is in an engaged state, the second gear set 42 and the fifth gear set 45 are working, and the torque is sequentially output to the front sprocket 32 ​​through the first transmission shaft 46, the third gear 421, the fourth gear 422, the shift engaging member 512 of the first shift assembly 51A, the second transmission shaft 47, the second one-way clutch 49, the tenth gear 452, the ninth gear 451, and the transmission sleeve 31. The gear set is a compound transmission of first speed-increasing transmission and then speed-increasing transmission.

[0190] Fig. 22 This is the sixth gear power transmission path diagram of the mid-shaft transmission.

[0191] The shift engaging member 512 of the first shift assembly 51A is engaged with the fourth gear 422, the shift engaging member 512 of the third shift assembly 51C is engaged with the seventh gear 441, the first one-way clutch 48 and the second one-way clutch 49 are both in a disengaged state, the second gear set 42 and the fourth gear set 44 are working, and the torque passes through the first transmission shaft 46, the third gear 421, the fourth gear 422, the shift engaging member 512 of the first shift assembly 51A, the second transmission shaft 47, the eighth gear 442, the seventh gear 441, the shift engaging member 512 of the third shift assembly 51C, and the transmission sleeve 31 in sequence, and is then output to the front sprocket 32. The gear set is a compound transmission that first increases the speed and then decreases the speed.

[0192] Fig.23 This is the power transmission path diagram for the seventh gear of the mid-shaft transmission.

[0193] The shift engaging member 512 of the first shift assembly 51A is engaged with the fourth gear 422, the shift engaging member 512 of the fourth shift assembly 51D is engaged with the sixth gear 432, the first one-way clutch 48 and the second one-way clutch 49 are both in a disengaged state, the second gear set 42 and the third gear set 43 are working, and the torque passes through the first transmission shaft 46, the third gear 421, the fourth gear 422, the shift engaging member 512 of the first shift assembly 51A, the second transmission shaft 47, the shift engaging member 512 of the fourth shift assembly 51D, the sixth gear 432, the fifth gear 431, and the transmission sleeve 31 in sequence and is output to the front sprocket 32. The gear set is a compound transmission of first speed increase transmission and then speed increase transmission.

[0194] The speed increase and decrease transmission is related to the number of teeth of the gears, and only represents the gear set in the attached figure of this embodiment. The transmission ratio of the middle shaft transmission can be flexibly adjusted according to the actual needs. In addition, the gears of the middle shaft transmission are not arranged according to the first gear to the seventh gear mentioned above, but are arranged from small to large or from large to small according to the actual transmission ratio. The gears are named from the first to the seventh only to distinguish the gears.

[0195] 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. The mid-mounted motor also includes a motor, and the motor is connected to the first transmission shaft 46, the second transmission shaft 47 or the transmission sleeve 31. The motor can be connected to the first transmission shaft 46, the second transmission shaft 47 or the transmission sleeve 31 through any one of chain drive, belt drive, and gear drive. When the motor is working, in addition to the torque of the rider's pedaling, there is also the torque generated by the motor. The two torques are superimposed and output to the front sprocket 32, allowing the rider to obtain a higher riding speed or a longer riding distance in a labor-saving riding manner.

[0196] Compared with the rear motor (hub motor) with gear shifting function, the mid-mounted motor with gear shifting function has a speed change structure on the frame instead of the rear wheel. 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. The frame 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.

[0197] The weight of the rear motor is concentrated on the rear wheel, which is not conducive to the vehicle's take-off and jumping. The weight of the mid-mounted motor is concentrated near the lower center of gravity of the frame, which has less impact on the balance of the entire vehicle and can greatly improve handling performance.

[0198] Example 2

[0199] Fig.24 It is a schematic diagram of the structure of the middle shaft transmission. Fig.25 Schematic diagram of the structure of the gear and the shift assembly. The difference from the first embodiment is that the present embodiment does not include the lever mechanism 53, but the shift control shaft 54 ​​still drives the shift engagement member 512 to engage or disengage with the gear of the gear set through the lever transmission.

[0200] In this embodiment, the shift control shaft 54 ​​directly drives the shift engagement member 512, that is, the control groove 541 of the shift control shaft 54 ​​is directly slidably connected with the guide portion 5111 of the shift engagement member 512. In this embodiment, a third bracket 55 is also included. The third bracket 55 is arranged below the gear set. The two ends of the third bracket 55 are respectively fixed to the first mounting plate 11 and the second mounting plate 12. The length of the fork body 5113 is extended to the third bracket 55. The fork body 5113 is hinged on the third bracket 55 at one end away from the guide portion 5111 to form a fulcrum. The length from the guide portion 5111 to the fulcrum is greater than the length from the axis of the shift engagement member 512 to the fulcrum. The length from the axis of the shift engagement member 512 to the fulcrum is the resistance arm, and the length from the fulcrum to the first end 5311 is the power arm. The power arm is about twice the resistance arm, which can also help the shift engagement portion 5121 of the shift engagement member 512 to better engage or separate with the engagement portion of the gear or the transmission sleeve 31.

[0201] A fourth elastic member 533 is disposed between the fork body 5113 and the third bracket 55. The fourth elastic member 533 is a tension spring, and after being assembled, the fourth elastic member 533 has a certain pre-tightening force, and has a tendency to push the fork body 5113 toward the direction of the engagement portion of the gear.

[0202] Compared with the solution of Example 1, the solution of Example 2 has more direct transmission of the shift control shaft 54 ​​and smoother gear shifting.

[0203] Example 3

[0204] Fig.26 It is a schematic diagram of the structure of the middle shaft transmission. Fig. 27 Schematic diagram of the structure of the gear and the shift assembly. This embodiment is a combination of Embodiment 1 and Embodiment 2. This embodiment includes a lever mechanism 53, and the shift control shaft 54 ​​is connected to the shift assembly 51 through the lever mechanism 53. The lever mechanism 53 includes a lever 531 and a fourth bracket 56. The lever 531 includes a first end 5311, a second end 5312 and a connecting hole 5313. The connecting hole 5313 is arranged between the first end 5311 and the second end 5312. The fourth bracket 56 is provided with a movable groove 5321. The second end 5312 of the lever 531 is rotatably installed in the movable groove 5321 to form a first fulcrum. The shift control shaft 54 ​​is provided with a control groove 541. The first end 5311 of the lever 531 can slide in the control groove 541. The connecting hole 5313 is connected to the shift assembly 51. The length from the first fulcrum to the first end 5311 is greater than the length from the second end 5312 to the connecting hole 5313. This structure forms a first heavy lever.

[0205] This embodiment further includes a third bracket 55, and the fork body 5113 is hinged on the third bracket 55 at one end away from the guide portion 5111 to form a second fulcrum, and the length from the guide portion 5111 to the second fulcrum is greater than the length from the axis of the shifting engagement member 512 to the second fulcrum. This structure forms a second heavy lever.

[0206] The present embodiment also includes a second bracket 532, the second bracket 532 is provided with a fixing portion 5322, a fourth elastic member 533 is provided between the fixing portion 5322 and the second end portion 5312, the fourth elastic member 533 is a tension spring in the present embodiment, the fourth elastic member 533 acts on the first end portion 5311 to make the first end portion 5311 have a movement tendency toward the corresponding engaged gear of the shift assembly 51, the movable groove 5321 is a waist-shaped groove, and the first end portion 5311 can slide in the movable groove 5321.

[0207] Embodiment 3 combines the advantages of Embodiment 1 and Embodiment 2, realizes a dual-lever driven shift assembly 51, and further improves the shift success rate.

[0208] In the description of this specification, the description with reference to the terms "one embodiment", "certain embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0209] 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, and these all belong to the protection scope of the present invention.

Claims

1. A mid-shaft transmission, characterized in that: include: A transmission mechanism (4) comprising two or more gear sets, a first transmission shaft (46) and a second transmission shaft (47), each of the gear sets comprising a pair of mutually meshing gears, the gears of the gear sets being respectively arranged on the first transmission shaft (46) and the second transmission shaft (47), and the transmission mechanism (4) having at least two transmission ratios; An input assembly (2) connected to the first transmission shaft (46) and used for inputting torque to the first transmission shaft (46); An output assembly (3), connected to the gear set, for outputting torque; A gear shift mechanism (5) for switching the operation of different gear sets to change the transmission ratio of the transmission mechanism (4); A gear shift assist mechanism (6), when the gear shift mechanism (5) is unable to switch between different gear sets, the torque of the second transmission shaft (47) is transmitted to the gear shift mechanism (5) via the gear shift assist mechanism (6) to smoothly complete the gear shift operation.

2. The mid-shaft transmission according to claim 1, characterized in that: The shift mechanism (5) comprises a shift assembly (51) and a shift control shaft (54); the shift assembly (51) is slidably connected to the shift control shaft (54) and is used to control the reciprocating motion of the shift assembly (51).

3. The mid-shaft transmission according to claim 2, characterized in that: The shift assembly (51) comprises a shift driving member (511) and a shift engaging member (512), wherein the shift engaging member (512) is rotatably mounted on the shift driving member (511), and the shift control shaft (54) drives the shift engaging member (512) to engage with or disengage the gear of the gear set.

4. The mid-shaft transmission according to claim 3, characterized in that: The shift control shaft (54) is provided with a control groove (541), and the control groove (541) of the shift control shaft (54) is configured to be able to decompose the torque in the first rotation direction input to the second transmission shaft (47) into a thrust force on the shift assembly (51) to assist the shift engagement member (512) in separating from the gears of the gear set.

5. The mid-shaft transmission according to claim 1, characterized in that: The shift assist mechanism (6) comprises a torque input member, a first connecting member (61), a second connecting member (62) and a third connecting member (63); the torque input member has a torque in a first rotational direction; the first connecting member (61) and the third connecting member (63) are rotatably supported on the second connecting member (62); the first connecting member (61) is connected to the third connecting member (63) via a second elastic member (65); the second elastic member (65) provides a pre-tightening torque; the first connecting member (61) rotates along the first rotational direction; when the torque input to the first connecting member (61) exceeds the pre-tightening torque, the second elastic member (65) is deformed, and the first connecting member (61) and the third connecting member (63) rotate relative to each other, so that the third connecting member (63) and the torque input member are engaged to transmit the torque of the torque input member to the third connecting member (63).

6. The mid-shaft transmission according to claim 5, characterized in that: The third connecting member (63) moves axially along the first rotational direction to engage with the torque input member.

7. The mid-shaft transmission according to claim 6, characterized in that: The third connecting member (63) is provided with an eighth engaging portion (633), and the torque input member is provided with a fifth engaging portion (471). The eighth engaging portion (633) is arranged opposite to the fifth engaging portion (471), and the eighth engaging portion (633) of the third connecting member (63) can be engaged with or separated from the fifth engaging portion (471) of the torque input member.

8. The mid-shaft transmission according to claim 5, characterized in that: The first connecting member (61) is provided with a sixth engaging portion (614), and the third connecting member (63) is provided with a seventh engaging portion (632). The sixth engaging portion (614) and the seventh engaging portion (632) are arranged opposite to each other. When the torque input by the first connecting member (61) does not exceed the pre-tightening torque, the sixth engaging portion (614) of the first connecting member (61) and the seventh engaging portion (632) of the third connecting member (63) remain engaged, so that the first connecting member (61) and the third connecting member (63) rotate synchronously. The second connecting member (62) is sleeved with a third elastic member (66), and the third elastic member (66) acts on the third connecting member (63) to keep the sixth engaging portion (614) of the first connecting member (61) engaged with the seventh engaging portion (632) of the third connecting member (63).

9. The mid-shaft transmission according to claim 8, characterized in that: The third connecting member (63) is provided with a connecting groove (631), the first connecting member (61) is provided with a blocking portion (615), the blocking portion (615) extends into the connecting groove (631), and the length of the connecting groove (631) is longer than the length of the blocking portion (615); When the first connecting member (61) rotates along the first rotation direction, the blocking portion (615) abuts against one end of the connecting groove (631), the sixth engaging portion (614) of the first connecting member (61) is separated from the seventh engaging portion (632) of the third connecting member (63), and the seventh engaging portion (632) of the third connecting member (63) is pushed to make the third connecting member (63) slide axially along the first rotation direction, so that the third connecting member (63) is engaged with the torque input member; When the first connecting member (61) rotates along a second rotation direction opposite to the first rotation direction, the blocking portion (615) abuts against the other end of the connecting groove (631), the sixth engaging portion (614) of the first connecting member (61) engages with the seventh engaging portion (632) of the third connecting member (63), and the third connecting member (63) rotates along the second rotation direction following the first connecting member (61).

10. The mid-shaft transmission according to claim 7, characterized in that: The first connecting member (61) is provided with a first mounting groove (612), a first elastic member (64) is provided in the first mounting groove (612), one end of the first elastic member (64) is connected to the first connecting member (61), and the other end of the first elastic member (64) is connected to the second connecting member (62).

11. The mid-shaft transmission according to claim 10, characterized in that: The first connecting member (61) is provided with a second mounting groove (613) on a side opposite to the first mounting groove (612), and the second elastic member (65) is installed in the second mounting groove (613), one end of the second elastic member (65) is connected to the first connecting member (61), and the other end of the second elastic member (65) is connected to the third connecting member (63).

12. The mid-shaft transmission according to claim 5, characterized in that: The outer peripheral surface of the first connecting member (61) is provided with a spiral wire groove (611).

13. The mid-shaft transmission according to claim 5, characterized in that: The edge of the third connecting member (63) is provided with gear teeth (634).

14. The mid-shaft transmission according to claim 2, characterized in that: The shift assembly (51) comprises a shift driving member (511) and a shift engaging member (512), wherein the shift engaging member (512) is rotatably mounted on the shift driving member (511), and the shift control shaft (54) drives the shift engaging member (512) to engage with or disengage the gear of the gear set through a lever transmission.

15. The mid-shaft transmission according to claim 14, characterized in that: The gear shift driving member (511) comprises a guide portion (5111) and a fork body (5113), wherein the guide portion (5111) is slidably connected to a control groove (541) of the gear shift control shaft (54), and the gear shift engaging member (512) is rotatably mounted on the fork body (5113).

16. The mid-shaft transmission according to claim 15, characterized in that: It also includes a lever mechanism (53), and the shift control shaft (54) is connected to the shift assembly (51) through the lever mechanism (53).

17. The mid-shaft transmission according to claim 16, characterized in that: The lever mechanism (53) comprises a lever (531) and a second bracket (532), wherein the lever (531) comprises a first end (5311), a second end (5312) and a connecting hole (5313), wherein the connecting hole (5313) is arranged between the first end (5311) and the second end (5312), wherein the second bracket (532) is provided with a movable groove (5321), wherein the second end (5312) of the lever (531) is rotatably mounted in the movable groove (5321) to form a fulcrum, wherein the shift control shaft (54) is provided with a control groove (541), wherein the first end (5311) of the lever (531) is slidable in the control groove (541), wherein the connecting hole (5313) is connected to the shift assembly (51), and the length from the fulcrum to the first end (5311) is greater than the length from the second end (5312) to the connecting hole (5313).

18. The mid-shaft transmission according to claim 17, characterized in that: The second bracket (532) is provided with a fixing portion (5322), and a fourth elastic member (533) is provided between the fixing portion (5322) and the second end portion (5312). The fourth elastic member (533) acts on the second end portion (5312) so that the second end portion (5312) has a movement tendency toward the corresponding gear engaged with the shift assembly (51), and the movable groove (5321) is a waist-shaped groove, and the second end portion (5312) can slide in the movable groove (5321).

19. The mid-shaft transmission according to claim 15, characterized in that: It also includes a third bracket (55), and the fork body (5113) is hinged on the third bracket (55) at one end away from the guide portion (5111) to form a fulcrum, and the length from the guide portion (5111) to the fulcrum is greater than the length from the axis of the shift coupling member (512) to the fulcrum.

20. The mid-shaft transmission according to claim 19, characterized in that: A fourth elastic member (533) is provided between the fork body (5113) and the third bracket (55).

21. The mid-shaft transmission according to claim 15, characterized in that: The invention also includes a lever mechanism (53), wherein the gear shift control shaft (54) is connected to the gear shift assembly (51) via the lever mechanism (53), wherein the lever mechanism (53) includes a lever (531) and a fourth bracket (56), wherein the lever (531) includes a first end (5311), a second end (5312) and a connecting hole (5313), wherein the connecting hole (5313) is arranged between the first end (5311) and the second end (5312), and wherein the fourth bracket (56) is provided with a movable groove (5321). , the second end portion (5312) of the lever (531) is rotatably mounted in the movable groove (5321) to form a first fulcrum, the shift control shaft (54) is provided with a control groove (541), the first end portion (5311) of the lever (531) can slide in the control groove (541), the connecting hole (5313) is connected to the shift assembly (51), and the length from the first fulcrum to the first end portion (5311) is greater than the length from the second end portion (5312) to the connecting hole (5313); It also includes a third bracket (55), and the fork body (5113) is hinged on the third bracket (55) at one end away from the guide portion (5111) to form a second fulcrum, and the length from the guide portion (5111) to the second fulcrum is greater than the length from the axis of the shift coupling member (512) to the second fulcrum.

22. The mid-shaft transmission according to claim 21, characterized in that: The invention also includes a second bracket (532), wherein the second bracket (532) is provided with a fixing portion (5322), and a fourth elastic member (533) is provided between the fixing portion (5322) and the second end portion (5312), wherein the fourth elastic member (533) acts on the first end portion (5311) so that the first end portion (5311) has a movement tendency toward a gear corresponding to the gear shifting assembly (51) and engaged therewith, and the movable groove (5321) is a waist-shaped groove, and the first end portion (5311) can slide in the movable groove (5321).

23. The mid-shaft transmission according to claim 1, characterized in that: The output assembly (3) comprises a transmission sleeve (31) and a front sprocket (32) fixed to each other, and the transmission sleeve (31) is connected to the gear set and is used to output torque to the front sprocket (32).

24. The mid-shaft transmission according to claim 3, characterized in that: The inner circumferential surface of the shift engaging member (512) is provided with a sliding portion, and the shift engaging member (512) can be slidably matched with the first transmission shaft (46), the second transmission shaft (47) and the transmission sleeve (31).

25. The mid-shaft transmission according to claim 1, characterized in that: It also includes a one-way clutch, which is arranged between the first transmission shaft (46) and / or the second transmission shaft (47) and the gear of the gear set. When the gear set where the one-way clutch is located is working, the one-way clutch is engaged; when the gear shifting mechanism (5) switches the gear set where the one-way clutch is located to another gear set for operation, the one-way clutch is disengaged so that the gear set where the one-way clutch is located does not work.

26. The mid-shaft transmission according to claim 25, characterized in that: The gear set is a speed-increasing transmission, a speed-reducing transmission, or a compound transmission of a speed-increasing transmission and a speed-reducing transmission.

27. The mid-shaft transmission according to claim 26, characterized in that: At least two gear sets are included in the speed increasing transmission, and the one-way clutch is arranged between the gear with the smallest number of teeth and the first transmission shaft (46).

28. The mid-shaft transmission according to claim 27, characterized in that: The one-way clutch comprises a first one-way clutch (48); the gear set comprises a first gear set (41) and a second gear set (42); the first gear set (41) comprises a first gear (411) and a second gear (412) which are externally meshed with each other; the second gear set (42) comprises a third gear (421) and a fourth gear (422) which are externally meshed with each other; the number of teeth of the first gear (411) is smaller than the number of teeth of the third gear (421); the third gear (421) is fixed on the first transmission shaft (46); the first one-way clutch (48) is installed between the first gear (411) and the first transmission shaft (46); the second gear (412) is fixedly installed on the second transmission shaft (47); and the fourth gear (422) is rotatably installed on the second transmission shaft (47).

29. The mid-shaft transmission according to claim 28, characterized in that: When the first gear set (41) is working, the first one-way clutch (48) is engaged; when the first gear set (41) is switched to the second gear set (42) for working, the first one-way clutch (48) is disengaged to make the first gear set (41) not work.

30. The mid-shaft transmission according to claim 26, characterized in that: At least two gear sets are included in the reduction transmission, and the one-way clutch is arranged between the gear with the smallest number of teeth and the second transmission shaft (47).

31. The mid-shaft transmission according to claim 30, characterized in that: The one-way clutch comprises a second one-way clutch (49); the output assembly (3) comprises a transmission sleeve (31) and a front sprocket (32) fixed to each other; the transmission sleeve (31) is connected to the gear set and is used to output torque to the front sprocket (32); the gear set comprises a third gear set (43), a fourth gear set (44) and a fifth gear set (45); the third gear set (43) comprises a fifth gear (431) and a sixth gear (432) meshed with each other; the fourth gear set (44) comprises a seventh gear (441) and an eighth gear (442) meshed with each other; the fifth gear set (45) comprises a ninth gear (451) and a tenth gear (452) meshed with each other; The number of teeth of the sixth gear (432), the number of teeth of the eighth gear (442), and the number of teeth of the tenth gear (452) decrease in sequence; the eighth gear (442) is fixedly mounted on the second transmission shaft (47); the sixth gear (432) is rotatably mounted on the second transmission shaft (47); the second one-way clutch (49) is mounted between the tenth gear (452) and the second transmission shaft (47); the transmission sleeve (31) is rotatably mounted on the first transmission shaft (46); the fifth gear (431) and the ninth gear (451) are fixedly mounted on the transmission sleeve (31); and the seventh gear (441) is rotatably mounted on the transmission sleeve (31).

32. The mid-shaft transmission according to claim 31, characterized in that: When the fifth gear set (45) is working, the second one-way clutch (49) is engaged; when the fifth gear set (45) is switched to the third gear set (43) or the fourth gear set (44) to work, the second one-way clutch (49) is disengaged to make the fifth gear set (45) not work.

33. The mid-shaft transmission according to claim 25, characterized in that: The one-way clutch is arranged on one side of the gear.

34. The mid-shaft transmission according to claim 25, characterized in that: The one-way clutch is a roller type overrunning clutch.

35. A mid-mounted motor, characterized in that: It comprises a mid-shaft transmission as described in any one of claims 1 to 34, and also comprises a motor, wherein the motor is connected to the first transmission shaft (46), the second transmission shaft (47) or the transmission sleeve (31).

36. The mid-mounted motor according to claim 35, characterized in that: The motor is connected to the first transmission shaft (46), the second transmission shaft (47) or the transmission sleeve (31) through any one of chain drive, belt drive and gear drive.

37. A vehicle, characterized in that: It comprises a mid-axle transmission as described in any one of claims 1-34 or a mid-mounted motor as described in any one of claims 35-36.

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