Mid-drive transmission, mid-drive electric motor, and vehicle

Abstract

The present patent application relates to the technical field of vehicle control. Disclosed are a mid-drive transmission, a mid-drive electric motor and a vehicle. The mid-drive transmission comprises: a bottom bracket axle, which is rotatably supported on a vehicle frame and a torque is inputted therefrom; a countershaft, which is parallel to the bottom bracket axle; a transmission mechanism, which is connected to the bottom bracket axle and the countershaft respectively and has at least two transmission ratios; a gear-shifting mechanism, which is linked to the transmission mechanism and is configured to change the transmission ratios of the transmission mechanism; a driving device, which is connected to the gear-shifting mechanism; and a front chainring, which is fixed to the transmission mechanism and by means of which the torque is outputted. In the mid-drive transmission of the present application, after the torque is inputted from the bottom bracket axle, the transmission mechanism can be driven to operate, and finally, the torque is outputted by means of the front chainring connected to the transmission mechanism; by means of controlling the driving device, the gear-shifting mechanism can be controlled to change the transmission ratios of the transmission mechanism, thereby achieving an automatic gear shifting function, and thus enriching the types of transmissions and expanding a user's options in terms of transmissions; and the structural composition of the transmission is clear and concise, and the functions of various components are explicit, which facilitates achieving a modular design.

Description

A center transmission, a center motor and a vehicle

[0001] The present application claims priority to Chinese Patent Application No. 202422215837.X, filed on September 10, 2024, entitled "A Shift Mechanism and Center Transmission", Chinese Patent Application No. 202411267434.8, filed on September 10, 2024, entitled "A Shift Mechanism and Center Transmission", Chinese Patent Application No. 202422915586.6, filed on November 28, 2024, entitled "A Shift Mechanism and Center Transmission", Chinese Patent Application No. 202411900113.7, filed on December 23, 2024, entitled "A Center Transmission and Center Motor", Chinese Patent Application No. 202411963562.6, filed on December 30, 2024, entitled "A Center Transmission and Center Motor", Chinese Patent Application No. 202423312724.8, filed on December 31, 2024, entitled "Center Transmission", Chinese Patent Application No. 202520169212.6, filed on January 24, 2025, entitled "A Shift Mechanism, Center Transmission and Center Motor", the contents of which are incorporated herein by reference in their entirety. TECHNICAL FIELD

[0002] The present patent application relates to the technical field of vehicle control, in particular to a center transmission, a center motor and a vehicle. BACKGROUND

[0003] Most of the existing speed changing devices of bicycles use chain multi-flywheel speed changing, which has the problems of chain sprocket wear, chain exposure to mud and sand, and the need for regular maintenance, inaccurate speed changing, speed changing damage, and the risk of chain falling during riding, prompting the industry to seek better speed changing solutions.

[0004] Currently, there are center transmission solutions in the industry, which can change gears at the right time by controlling the transmission, thereby realizing automatic gear shifting of the vehicle, reducing manual operation during user riding, and greatly improving user experience. However, there are currently few types of center transmissions, which inhibits the growth of differentiated demand users. SUMMARY

[0005] The purpose of the present patent application is to provide a center transmission, a center motor and a vehicle, aiming to enrich the types of center transmissions and solve the problem of few types of center transmissions, which inhibits the growth of differentiated demand users.

[0006] In a first aspect, the application provides a middle transmission, comprising:

[0007] a middle shaft rotatably supported by the frame and to which torque is inputted;

[0008] a secondary shaft parallel to the middle shaft;

[0009] a transmission mechanism connected to the middle shaft and the secondary shaft respectively and having at least two transmission ratios;

[0010] a shift mechanism connected to the transmission mechanism and used for changing the transmission ratio of the transmission mechanism;

[0011] a driving device connected to the shift mechanism;

[0012] a front sprocket fixed to the transmission mechanism and outputting torque.

[0013] In a preferred embodiment, the transmission mechanism comprises a plurality of first gears rotatably mounted on the secondary shaft and a plurality of second gears mounted on the middle shaft, each of the first gears being engaged with a corresponding second gear;

[0014] the shift mechanism is mounted in the secondary shaft to control locking and disengaging of the secondary shaft from any one or more of the first gears; when the first gears are locked with the secondary shaft, the secondary shaft rotates under the drive of the secondary shaft and drives the middle shaft through the second gears engaged with the first gears.

[0015] Further preferably, the shift mechanism comprises a pawl, an elastic member, a sliding member, a screw, a nut and a first fixing member;

[0016] the screw is used to rotate under the drive of the driving device, the nut is mounted on the screw, and the first fixing member is used to circumferentially limit the nut;

[0017] the sliding member is mounted in the secondary shaft and axially slidable along the secondary shaft, and the secondary shaft circumferentially limits the sliding member;

[0018] the nut is used to drive the sliding member to move axially along the secondary shaft, and the sliding member is rotatable in the circumferential direction of the nut;

[0019] the pawl and the elastic member are mounted in the secondary shaft and located outside the sliding member; the sliding member is provided with a second shift groove, and the axial width of the second shift groove is not greater than the sum of the widths of any two adjacent pawls;

[0020] The elastic member is used to press the first end of the pawl into the second shift groove when the slider slides to the position where the pawl is above the second shift groove, so that the second end of the pawl is lifted to lock the countershaft and the first gear; the slider lifts the first end of the pawl when it slides to the position where the pawl is away from the second shift groove, so that the second end of the pawl is reset to separate the countershaft and the first gear.

[0021] More preferably, the shift mechanism further comprises a bearing installed between the slider and the nut.

[0022] More preferably, the number of bearings is two, and the shift mechanism further comprises an axial positioning member arranged between the two bearings.

[0023] More preferably, the screw rod extends to the outside of the countershaft at least at one end, and is used to be connected with the driving device.

[0024] More preferably, the second shift groove is provided with a slope surface along the axial direction of the screw rod at the edges of both ends.

[0025] More preferably, the slider comprises a slider body and a boss protruding from the slider body, and the boss is installed in the countershaft and can slide along the axial direction of the countershaft.

[0026] More preferably, the shift mechanism further comprises a snap spring arranged at both ends of the nut, and the snap spring is used to limit the axial movement of the slider on the nut.

[0027] More preferably, the first fixing member comprises a plurality of fixing rods, and both ends of the fixing rods are installed on the housing where the shift mechanism is arranged.

[0028] More preferably, the plurality of fixing rods are arranged through the nut.

[0029] More preferably, each of the first gears corresponds to two pawls, and the two pawls are arranged on both sides of the slider, and the number of the second shift grooves on the slider is two.

[0030] More preferably, the shift mechanism further comprises a second fixing member, and the second fixing member is arranged outside the slider, and the pawl is rotationally connected with the second fixing member and can rotate around the second fixing member.

[0031] More preferably, the countershaft is provided with a limiting hole, the axial position of the first gear on the countershaft is consistent with the limiting hole, and the pawl corresponding to the first gear and the elastic member are arranged in the limiting hole.

[0032] In another preferred embodiment, the gear shifting mechanism comprises a sleeve, a pawl and an elastic member; the sleeve is located in the secondary shaft, the pawl and the elastic member are installed in the secondary shaft and located outside the sleeve; the sleeve is provided with a first shifting slot, and the sleeve is used to rotate under the drive of an external force; the elastic member presses the first end of the pawl into the first shifting slot when the sleeve rotates to the position where the first end of the pawl is above the first shifting slot, and makes the second end of the pawl lift up to lock the secondary shaft and the first gear, and the sleeve is tangent to the pawl to lift up the first end of the pawl when the first end of the pawl is away from the first shifting slot, so that the second end of the pawl resets to separate the secondary shaft and the first gear.

[0033] Further preferably, the first shifting slot is a slanted slot, and the middle line of the first shifting slot is not parallel to the middle axis of the sleeve.

[0034] More preferably, the gear shifting mechanism further comprises a sliding member, the sliding member is provided in the slanted slot and installed in the secondary shaft, the secondary shaft limits the sliding member in the circumferential direction and the sliding member can slide in the axial direction of the secondary shaft, when not shifting, the sliding member and the sleeve rotate synchronously with the secondary shaft, when shifting is needed, the sliding member drives the sleeve to rotate relative to the secondary shaft by axial movement.

[0035] More preferably, the gear shifting mechanism further comprises a screw rod, a nut and a first fixing member provided in the sleeve, the nut is installed on the screw rod, the first fixing member limits the nut in the circumferential direction, the screw rod drives the nut to move axially along the screw rod by rotating, so as to drive the sliding member to move axially along the screw rod.

[0036] More preferably, at least one end of the screw rod extends to the outside of the secondary shaft for connecting with the driving device.

[0037] More preferably, the first fixing member comprises a plurality of fixing rods, both ends of the fixing rods are installed on the housing where the gear shifting mechanism is located.

[0038] More preferably, the plurality of fixing rods are provided in the nut.

[0039] More preferably, each of the first gears corresponds to two pawls, the two pawls are respectively provided on both sides of the sleeve, and the number of the first shifting slots on the sleeve is two.

[0040] More preferably, the gear shifting mechanism further comprises a planetary gear assembly for driving the sleeve to rotate, the output end of the planetary gear assembly is connected with the sleeve or the screw rod.

[0041] In another preferred embodiment, the secondary shaft is hollow.

[0042] Further preferably, the transmission mechanism is a gear transmission.

[0043] The gear shifting mechanism comprises a reset member, a rotation control member and at least two pawls, the secondary shaft is provided with a recess, the pawls are rotatably installed in the recess, one end of the reset member abuts against the secondary shaft, the other end of the reset member abuts against one end of the pawls, and the outer periphery of the rotation control member is provided with a control groove formed along the circumferential direction thereof.

[0044] The pawl has a locking portion, a control portion and an extension portion, the control portion is located on the side opposite to the locking portion, and the control portion and the locking portion are connected through the extension portion, the locking portion of the pawl is located on the outer side of the rotation control member, and the control portion of the pawl is located on the inner side of the rotation control member.

[0045] When the rotation control member and the secondary shaft are deflected, the control portion of the pawl is popped up and enters the control groove, so that the gear of the transmission mechanism is fixed with the secondary shaft to change the transmission ratio.

[0046] Further preferably, the control portion is protruded from the extension portion with a triangular cross section.

[0047] Further preferably, a round corner is arranged at the position where the control portion contacts the inner periphery of the rotation control member.

[0048] Further preferably, the locking portion and the control portion are located on the same radial plane.

[0049] Further preferably, the outer periphery of the rotation control member is provided with an avoiding groove formed along the circumferential direction thereof, and the extension portion of the pawl passes through the avoiding groove to be connected with the control portion and the locking portion respectively.

[0050] Further preferably, the driving device is hidden in the inner side of the secondary shaft.

[0051] Further preferably, the transmission mechanism is a gear transmission.

[0052] The gear shifting mechanism comprises at least two pawls, a reset member and a rotation control member, the secondary shaft is provided with a recess, the pawls are rotatably installed in the recess, one end of the reset member abuts against the secondary shaft, the other end of the reset member abuts against one end of the pawls, the outer periphery of the rotation control member is provided with a control groove, and the pawls are arranged on the outer side of the rotation control member.

[0053] When the rotation control member is deflected from the rotation angle of the secondary shaft, one end of the pawl enters the control groove, so that the gear of the transmission mechanism is fixed with the secondary shaft to change the transmission ratio.

[0054] More preferably, the control groove is a spiral groove.

[0055] More preferably, the control groove includes at least two through grooves arranged in a spiral shape, the through grooves being arranged along the circumferential direction of the rotation control member, and adjacent two through grooves being not communicated.

[0056] More preferably, the rotation control member is arranged on the inner side of the secondary shaft, and the driving device is arranged on the inner side of the rotation control member.

[0057] More preferably, the speed mixing mechanism is further arranged, and the speed mixing mechanism is connected with the shift mechanism, the secondary shaft and the driving device respectively.

[0058] When the driving device does not perform the shift operation, the speed mixing mechanism synchronizes the rotation of the shift mechanism and the secondary shaft; when the driving device performs the shift operation, the speed mixing mechanism causes the rotation control member of the shift mechanism and the rotation angle of the secondary shaft to be deflected.

[0059] More preferably, the speed mixing mechanism includes a first ring gear, a first sun gear, a planet carrier, a plurality of planetary gears, a second ring gear and a second sun gear, the plurality of planetary gears being rotatably connected to the planet carrier, the plurality of planetary gears being meshed with the first ring gear, the first sun gear, the second ring gear and the second sun gear respectively, the first ring gear being connected with the rotation control member of the shift mechanism, the second ring gear being connected with the secondary shaft, and the first sun gear being connected with the driving device.

[0060] The transmission further includes a housing, the housing being fixedly connected with the vehicle frame, the secondary shaft being rotatably supported in the housing, the front sprocket being located outside the housing, the transmission mechanism and the shift mechanism being arranged inside the housing, the middle shaft extending through the housing and being rotatably supported on the vehicle frame at the two ends of the middle shaft extending out of the housing, and the input assembly including a left crank and a right crank.

[0061] The second sun gear is further fixedly connected with the housing.

[0062] Further preferably, the multiple planetary gears are double planetary gears, the double planetary gears comprising first and second planetary gears with the same number of teeth, the first planetary gears meshing with the first ring gears and the first sun gears respectively, and the second planetary gears meshing with the second ring gears and the second sun gears respectively.

[0063] Further preferably, the multiple planetary gears are four planetary gears, the four planetary gears comprising third and sixth planetary gears with the same number of teeth, and fourth and fifth planetary gears with the same number of teeth, the third planetary gears having a smaller number of teeth than the fourth planetary gears, the third planetary gears meshing with the first ring gears, the fourth planetary gears meshing with the first sun gears, the sixth planetary gears meshing with the second ring gears, and the fifth planetary gears meshing with the second sun gears.

[0064] Further preferably, the gear feedback device comprises a plurality of row-arranged Hall elements and magnets, the driving device is connected with a driving device reduction mechanism, the driving device reduction mechanism comprises a reduction sun gear, a reduction planetary gear, a reduction planetary carrier and a reduction ring gear, the reduction planetary gear is rotatably mounted on the reduction planetary carrier, the reduction planetary gear meshes with the reduction sun gear and the reduction ring gear respectively, the reduction sun gear is fixedly connected with the driving device, the magnets are arranged on the reduction ring gear, the reduction planetary carrier is connected with the housing, and the Hall elements are used to sense the magnetic field intensity of the magnets to obtain pulse signals for determining the gear position to which the gear shifting mechanism rotates.

[0065] Further preferably, the maximum angle of the plurality of row-arranged Hall elements does not exceed 360 degrees.

[0066] Further preferably, the driving device is a gear shifting motor, and the gear shifting motor is fixed to the housing.

[0067] Further preferably, the transmission mechanism comprises a first gear set and a second gear set, and torque is input from the middle shaft, sequentially passes through the first gear set and the second gear set, and is then output to the front sprocket.

[0068] Further preferably, the first gear set comprises a first driving gear and a first driven gear that mesh with each other, the first driving gear is fixedly connected with the middle shaft, and the first driven gear is fixedly connected with the auxiliary shaft.

[0069] The second gear set comprises a second driving gear and a second driven gear which are in mesh with each other, the second driving gear is movably connected to the lay shaft, the second driving gear is relatively fixed or relatively movable with respect to the lay shaft by the gear shifting mechanism to shift gears, the second driven gear is fixedly connected with a transmission sleeve, and the transmission sleeve is movably connected with the intermediate shaft.

[0070] More preferably, a plurality of second driving gears and a plurality of second driven gears are provided, one of the second driving gears with the least number of teeth is fixed to the lay shaft, and a one-way clutch is arranged between one of the second driven gears with the most number of teeth and the transmission sleeve.

[0071] In another preferred embodiment, the gear shifting mechanism comprises a sleeve, a pawl, and a resilient member, the sleeve is provided with a first gear shifting groove, and the resilient member is configured to drive the first end of the pawl into the first gear shifting groove and make the second end of the pawl lift up when the first end of the pawl is above the first gear shifting groove, so as to lock the first gear located outside the sleeve.

[0072] The pawl comprises a first inclined surface, the first inclined surface is configured to abut against and slide along the edge of the first gear shifting groove when the first end of the pawl enters the first gear shifting groove, the edge of the first gear shifting groove is shaped as a helical surface around the central axis of the sleeve, the included angle between the helical line around the central axis in the helical surface and the first inclined surface at the tangent of the first contact point is less than 10 degrees, and the first contact point is the contact point between the first inclined surface and the helical line.

[0073] More preferably, the resilient member is located at the first end of the pawl and is configured to press against the first end of the pawl to make the first end of the pawl enter the first gear shifting groove when the first end of the pawl is above the first gear shifting groove; or,

[0074] The resilient member is located at the second end of the pawl and is configured to lift up the second end of the pawl when the first end of the pawl is above the first gear shifting groove; or,

[0075] The pawl further comprises a second inclined surface, the second inclined surface is configured to abut against and slide along the edge of the first gear shifting groove when the pawl leaves the first gear shifting groove, the included angle between the helical line around the central axis in the helical surface and the second inclined surface at the tangent of the second contact point is less than 10 degrees, and the second contact point is the contact point between the second inclined surface and the helical line.

[0076] More preferably, the pawl rotates around a first axis, and the included angle between the line connecting a point on the first axis and the first inclined surface and the first inclined surface is less than 60 degrees.

[0077] Further preferably, the gear shifting mechanism further comprises a second fixing member outside the sleeve, the pawl is sleeved on the second fixing member, and the first axis is a central axis of the second fixing member.

[0078] Further preferably, the pawl rotates around the first axis, and an intersection between the first axis and a median longitudinal surface of the pawl and any point on the first inclined surface form a line, and an included angle between the line and the first inclined surface is less than 60 degrees.

[0079] Further preferably, the sleeve is provided with two first gear shifting grooves in the same spiral form, and each first gear shifting groove corresponds to a group of pawls.

[0080] Further preferably, the driving device is in transmission connection with the sleeve and is used for driving the sleeve to rotate.

[0081] Further preferably, the driving device comprises a sliding member, the sliding member is arranged through the first gear shifting groove, and is used for moving along an axial direction of the sleeve to drive the sleeve to rotate.

[0082] In another preferred embodiment, the transmission mechanism comprises a first input gear fixedly installed on the main shaft and a second input gear fixedly installed on the auxiliary shaft, and the first input gear and the second input gear are in meshing connection; the first input gear is used for rotating under the driving of the main shaft, thereby driving the second input gear to rotate and driving the auxiliary shaft to rotate.

[0083] The transmission mechanism further comprises a plurality of first transmission gears installed on the main shaft and a plurality of second transmission gears installed on the auxiliary shaft, and each first transmission gear and a corresponding second transmission gear are in meshing connection.

[0084] The gear shifting mechanism is installed on the auxiliary shaft, and is used for driving one of the second transmission gears to rotate under the driving of the auxiliary shaft, thereby driving a corresponding first transmission gear to rotate and driving the front chain wheel to rotate.

[0085] Further preferably, the main shaft is sleeved with an output sleeve, and the first transmission gears and the front chain wheel are installed on the output sleeve.

[0086] The main shaft is installed with a crank at both ends, and a torque is input into the main shaft through the crank.

[0087] Further preferably, the first sensor further comprises a fourth fixing member and a rotating member, the rotating member is installed on the middle shaft, the fourth fixing member is arranged on the transfer case or the vehicle where the transfer case is arranged, and the rotating member is rotatable relative to the fourth fixing member, and the positional relationship between the fourth fixing member and the rotating member is used to determine the rotating speed or position of the front sprocket.

[0088] Further preferably, the first input gear is provided with a first mounting hole, and the rotating member is installed in the first mounting hole.

[0089] Further preferably, the fourth fixing member is sleeved on the middle shaft.

[0090] Further preferably, the transfer case further comprises a second sensor, and the second sensor is installed on the auxiliary shaft and used to detect the torque of the first input gear or the second input gear.

[0091] Further preferably, the transfer case further comprises a housing, the fourth fixing member is installed in the housing, the fourth fixing member comprises a mounting shell and at least one Hall element installed in the mounting shell, and the rotating member comprises a magnet, and the magnet is fixed to the first input gear.

[0092] Further preferably, the mounting shell is provided with a protrusion, and the protrusion is fixedly installed in the housing.

[0093] In a second aspect, the application provides a transfer case, which comprises the above-mentioned transfer case, a power-assisted motor and a power-assisted motor deceleration mechanism, and the power-assisted motor is connected with the transmission mechanism through the power-assisted motor deceleration mechanism.

[0094] In a third aspect, the application provides a vehicle, which comprises a vehicle body and the above-mentioned transfer case of the second aspect, and the transfer case is installed on the vehicle body.

[0095] The transfer case provided by the application has the following beneficial effects:

[0096] The transfer case provided by the application has the following beneficial effects:

[0097] The structure of the middle transmission is clear and simple, the functions of each component are clear, the modular design is facilitated, and the appearance design requirements of the middle transmission are met. BRIEF DESCRIPTION OF DRAWINGS

[0098] In order to more clearly illustrate the technical solutions in the embodiments of the present patent application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced.

[0099] Fig. 1 is a shift principle diagram of a shift mechanism provided by an embodiment of the present application;

[0100] Fig. 2 is an assembly schematic diagram of the shift mechanism on a countershaft provided by an embodiment of the present application;

[0101] Fig. 3 is a schematic diagram one of the shift mechanism provided by an embodiment of the present application;

[0102] Fig. 4 is a partial exploded view of the shift mechanism provided by an embodiment of the present application;

[0103] Fig. 5 is a schematic diagram of a middle transmission provided by an embodiment of the present application;

[0104] Fig. 6 is a perspective view of the middle transmission provided by an embodiment of the present application;

[0105] Fig. 7 is a schematic diagram two of the shift mechanism provided by an embodiment of the present application;

[0106] Fig. 8 is a principle structure diagram of screw driving sliding movement of a sliding member;

[0107] Fig. 9 is a perspective view of the middle transmission (the shell, the front sprocket and the crank are hidden) in the present application;

[0108] Fig. 10 is a top view of Fig. 9;

[0109] Fig. 11 is a cross-sectional view one of Fig. 10;

[0110] Fig. 12 is an assembly schematic diagram of the countershaft and the shift mechanism;

[0111] Fig. 13 is a perspective view of a pawl;

[0112] Fig. 14 is a perspective view of a rotation control member;

[0113] Fig. 15 is a schematic diagram of a shift process of the shift mechanism;

[0114] Fig. 16 is a cross-sectional view of the shift process of the shift mechanism;

[0115] Fig. 17 is a perspective view of a rotation speed mixing mechanism;

[0116] Fig. 18 is an exploded view of the rotation speed mixing mechanism;

[0117] Figure 19 is a schematic diagram of a rotational speed mixing mechanism;

[0118] Figure 20 is a schematic diagram of a motor-in-the-middle structure according to the present application;

[0119] Figure 21 is a cross-sectional view of Figure 10;

[0120] Figure 22 is a schematic diagram of an assembly of a lay shaft and a shifting mechanism;

[0121] Figure 23 is a schematic diagram of a shifting process of the shifting mechanism;

[0122] Figure 24 is a cross-sectional view of the shifting process of the shifting mechanism;

[0123] Figure 25 is a perspective view of another embodiment of a rotational control member;

[0124] Figure 26 is a schematic diagram of a rotational speed mixing mechanism;

[0125] Figure 27 is a schematic diagram of another embodiment of a rotational speed mixing mechanism;

[0126] Figure 28 is a schematic diagram of a rotational speed mixing mechanism and a gear position feedback device;

[0127] Figure 29 is a schematic diagram of a structure of a gear position feedback device;

[0128] Figure 30 is a schematic diagram of a motor-in-the-middle structure according to the present application;

[0129] Figure 31 is a schematic diagram of a partial structure of a motor-in-the-middle transmission according to Embodiment 5;

[0130] Figure 32 is a schematic diagram of another perspective view of a partial structure of a motor-in-the-middle transmission according to Embodiment 5;

[0131] Figure 33 is a schematic diagram of a shifting mechanism according to Embodiment 5;

[0132] Figure 34 is a schematic diagram of a perspective view of a shifting mechanism according to Embodiment 5;

[0133] Figure 35 is a schematic diagram of another perspective view of a shifting mechanism according to Embodiment 5;

[0134] Figure 36 is a schematic diagram of an angle relationship between a first axis and a first inclined surface in a shifting mechanism according to Embodiment 5;

[0135] Figure 37 is a schematic diagram of a first inclined surface and a second inclined surface in a shifting mechanism according to Embodiment 5;

[0136] Figure 38 is a schematic diagram of an assembly of a motor-in-the-middle transmission and a crank according to the present embodiment;

[0137] Figure 39 is a schematic diagram of an assembly of an internal structure of a motor-in-the-middle transmission according to the present embodiment;

[0138] Fig. 40 is a schematic view of the internal structure of the MTM according to the present embodiment;

[0139] Fig. 41 is a schematic view of the internal structure of the MTM according to the present embodiment from another perspective;

[0140] Fig. 42 is a sectional view of the MTM according to the present embodiment;

[0141] Fig. 43 is a schematic view of the shift mechanism according to the present embodiment;

[0142] Wherein, the reference numerals are: 1 - housing; 2 - main shaft; 3 - auxiliary shaft, 31 - groove; 4 - transmission mechanism, 41 - first gear set, 411 - first driving gear, 412 - first driven gear, 42 - second gear set, 421 - second driving gear, 4211 - locking groove, 422 - second driven gear; 5 - shift mechanism, 51 - pawl, 511 - locking portion, 512 - control portion, 513 - extension portion, 514 - rotating shaft portion, 52 - return member, 53 - rotating control member, 531 - control groove, 532 - avoiding groove, 54 - driving mechanism; 6 - driving device; 7 - rotating speed mixing mechanism, 71 - first ring gear, 72 - first sun gear, 73 - planet carrier, 74 - double planetary gear; 741 - first planetary gear, 742 - second planetary gear, 75 - second sun gear, 76 - second ring gear; 8 - input assembly, 81 - left crank, 82 - right crank; 9 - output assembly, 91 - transmission sleeve, 92 - front sprocket (toothed disc), 93 - one-way clutch; 10 - assist motor; 11 - assist motor speed reduction mechanism; 20 - fixing groove; 21 - clamping groove; 22 - concave sliding groove; 23 - limiting hole; 24 - second mounting hole; 30 - input mechanism; 34 - first input gear; 35 - second input gear; 40 - shift mechanism; 41 - first transmission gear; 42 - second transmission gear; 60 - first sensor; 61 - fourth fixing member; 611 - mounting shell; 612 - Hall element; 613 - protrusion; 62 - rotating member; 70 - output mechanism; 71 - output sleeve; 80 - second sensor; 200 - crank; 55 - sleeve; 551 - first shift groove; 12 - pawl; 121 - first inclined surface; 122 - second inclined surface; 13 - sliding member; 131 - second shift groove; 132 - sliding member body; 133 - boss; 14 - elastic member; 15 - screw rod; 16 - nut; 161 - bearing; 162 - axial positioning member; 163 - clamping spring; 17 - first fixing member; 171 - fixing rod; 18 - second fixing member; 19 - third fixing member; 32 - first gear; 33 - second gear. DETAILED DESCRIPTION

[0143] Embodiments of the present patent application are described below in detail, examples of the embodiments are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present patent application and cannot be understood as a limitation of the present patent application.

[0144] Reference throughout the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. Thus, the appearance of the phrases "in one embodiment" or "in some embodiments" in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0145] In the description of the present patent application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present patent application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present patent application.

[0146] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" and "second" can explicitly or implicitly include one or more of the features. In the present patent application, unless otherwise specifically defined and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated: it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present patent application can be understood according to the specific circumstances.

[0147] The embodiment of the application provides a kind of middle transmission.The middle transmission of the application is fixedly installed in the middle bottom of vehicle frame, as shown in Figure 6, and the middle transmission includes shell 1, middle shaft 2, auxiliary shaft 3 parallel with middle shaft 2, transmission mechanism 4, shift mechanism 5, driving device 6 and front sprocket 92, wherein transmission mechanism 4 is connected with middle shaft 2 and auxiliary shaft 3 respectively, with at least two transmission ratios;Driving device 6 is connected with shift mechanism 5, for driving shift mechanism to operate;

[0148] The housing 1 is internally provided with a containing cavity, the transmission mechanism 4 and the gear shifting mechanism 5 are arranged in the containing cavity, the housing 1 is fixed on a vehicle frame, the countershaft 3 is rotatably supported in the housing 1, all parts are internally concealed in the housing 1 except that the front sprocket 92 is exposed, the middle shaft 2 penetrates through the housing 1 at two ends and extends out of the housing 1 and is rotatably supported on the vehicle frame, the middle shaft 2 is fixedly connected with an input assembly 8 at two ends, the input assembly 8 comprises a left crank 81 and a right crank 82, the left crank 81 and the right crank 82 are rotatably connected with pedals, a rider pedals the pedals on the left crank 81 and the right crank 82 to generate a torque, the torque is transmitted to the middle shaft 2, and then the torque is input to the transmission mechanism 4 by the middle shaft 2; the gear shifting mechanism 5 is linked with the transmission mechanism 4 and is used for changing a transmission ratio and an output rotating speed of the transmission mechanism 4, different gear positions are switched by changing meshing relationships of different gears, the front sprocket 92 is fixed on the transmission mechanism 4 and is used for outputting the torque, and the front sprocket 92 inputs the torque to a freewheel through chain transmission or belt transmission to drive a rear wheel of the vehicle to rotate, that is, the driving device can be a gear drive or a chain drive.

[0149] The middle shaft transmission is also referred to as a middle shaft transmission, and the front sprocket is also referred to as a flying disc or a toothed disc.

[0150] The middle shaft transmission is provided with a middle shaft, a countershaft, a transmission mechanism, a gear shifting mechanism, a driving device and a front sprocket, the driving device is connected with the gear shifting mechanism, the gear shifting mechanism is connected with the transmission mechanism, the transmission mechanism is connected with the middle shaft and the countershaft respectively, the torque is input through the middle shaft, the transmission mechanism is driven to operate, and finally the torque is output through the front sprocket connected with the transmission mechanism; simultaneously, the transmission ratio of the transmission mechanism is changed by controlling the gear shifting mechanism through the driving device, the automatic gear shifting function is realized, and then the transmission type is enriched and the selection of the user in the transmission aspect is enriched.

[0151] The middle shaft transmission has clear and simple structural components, the functions of each component part are clear, the modular design is facilitated, and the appearance design requirements of the middle shaft transmission in terms of small size and compactness are facilitated.

[0152] It should be noted that the gear shifting mechanism 5 can be installed in the middle shaft 2 of the middle shaft transmission or can be installed in the countershaft 3, and the middle shaft transmission is taken as an example to be described in detail.

[0153] The device can be used in bicycles, folding bicycles, Ebikes, electric assist bicycles, electric vehicles, electric motorcycles, cargo carrying electric vehicles, tricycles, scooters, electric scooters and the like.

[0154] In a preferred embodiment, as shown in Figure 5, the transmission mechanism comprises a plurality of first gears 32 rotatably mounted on the countershaft 3 and a plurality of second gears 33 mounted on the middle shaft, each first gear 32 is meshed with a corresponding second gear 33.

[0155] The shift mechanism 5 is installed in the countershaft 3 to control the locking and separation of the countershaft 3 and any one or more first gears 32; when the first gears 32 are locked with the countershaft 3, they rotate under the drive of the countershaft 3 and drive the middle shaft to rotate through the second gears meshing with the first gears 32. For example, the front sprocket 92 of the bicycle is installed on the middle shaft 22, and the rotation of the middle shaft 22 provides power for the bicycle to move forward.

[0156] Embodiment 1

[0157] In a preferred embodiment, the shift mechanism 5 is as shown in FIGS. 1 to 4, and specifically as follows:

[0158] The shift mechanism 5 includes a pawl 12, a sliding member 13, a resilient member 14, a screw rod 15, a nut 16, and a first fixing member 17. The screw rod 15 is used to rotate under the drive of a driving device, the nut 16 is installed on the screw rod 15, and the first fixing member 17 is used to circumferentially limit the nut 16;

[0159] The sliding member 13 is installed in the countershaft 3 and can slide axially along the countershaft 3, and the countershaft 3 circumferentially limits the sliding member 13; the nut 16 is used to drive the sliding member 13 to move axially along the countershaft 3, and the sliding member 13 is circumferentially rotatable on the nut 16; the pawl 12 and the resilient member 14 are installed in the countershaft 3 and located outside the sliding member 13; the sliding member 13 is provided with a second shift groove 131, and the axial width of the second shift groove 131 is less than or equal to the sum of the widths of any two adjacent pawls 12, so that one or two pawls 12 enter the second shift groove 131. The resilient member 14 is used to press the first end of the pawl 12 into the second shift groove 131 when the sliding member 13 slides to the position where the pawl 12 is above the second shift groove 131, so that the second end of the pawl 12 is lifted to lock the countershaft 3 and the first gear 32; when the sliding member 13 slides to the position where the pawl 12 is away from the second shift groove 131, the first end of the pawl 12 is lifted, so that the second end of the pawl 12 resets to separate the countershaft 3 and the first gear 32.

[0160] In this embodiment, the shift mechanism includes a pawl, a resilient member, a sliding member, a screw rod, a nut, and a first fixing member, the nut is installed on the screw rod, and the first fixing member circumferentially fixes the nut, so that when the screw rod rotates, the nut moves axially along the screw rod, and in turn drives the sliding member to move axially. By moving the sliding member axially, gear shifting can be achieved, and the pawl locks the countershaft 3 and the first gear 32 under the action of the resilient member (i.e. engages the gear), and separates the countershaft 3 and the first gear 32 under the action of the sliding member (i.e. disengages the gear), which realizes soft connection for engaging the gear and hard connection for disengaging the gear, and improves the reliability of gear shifting.

[0161] Specifically, the sliding piece 13 is limited in the circumferential direction by the secondary shaft 3, so that the sliding piece 13 can rotate synchronously with the secondary shaft 3. During gear shifting, the screw rod 15 rotates under the drive of the driving device. Since the nut 16 is threadedly connected with the screw rod 15, the first fixing piece 17 limits the nut 16 in the circumferential direction, so that the nut 16 moves in the axial direction under the drive of the screw rod 15, and in turn drives the sliding piece 13 to move in the axial direction, so that the relative position of the sliding piece 13 and the pawl 12 changes. Since the second shifting groove 131 is arranged on the sliding piece 13, the relative position of the second shifting groove 131 and the pawl 12 also changes. The elastic piece 14 is arranged on the pawl 12 and the secondary shaft 3 at two ends thereof.

[0162] Exemplarily, the secondary shaft 3 is provided with a positioning piece, and the elastic piece 14 is arranged on the positioning piece and abuts against the pawl 12 and the secondary shaft 3 at two ends thereof. The elastic piece 14 applies a force to the first end of the pawl 12 towards the sliding piece 13. During the movement of the sliding piece 13 in the axial direction, when the first end of the pawl 12 is above the second shifting groove 131, the elastic piece 14 abuts against the first end of the pawl 12, so that the first end of the pawl 12 enters the second shifting groove 131, and in turn the second end of the pawl 12 is lifted to protrude from the secondary shaft 3, and in turn the second end of the pawl 12 is engaged with the first gear 32, so as to lock the first gear 32 and the secondary shaft 3, that is, to realize gear engagement. When the first end of the pawl 12 is away from the second shifting groove 131, the first end of the pawl 12 abuts against the sliding piece 13, so that the sliding piece 13 lifts the first end of the pawl 12, and in turn the second end of the pawl 12 is reset, so as to disengage the pawl 12 from the first gear 32, and realize the separation of the first gear 32 and the secondary shaft 3, that is, to realize gear disengagement.

[0163] Through the above structure design, the pawl 12 is engaged under the elastic force of the elastic piece 14, and is disengaged under the thrust of the sliding piece 13, so as to realize soft connection engagement and hard connection disengagement, and improve the reliability of gear shifting. At the same time, since the pawl 12 is subjected to greater force when the sliding piece 13 rotates, gear shifting can be realized in the loaded state of the pawl 12. At the same time, the control precision of the pawl 12 can be improved by moving the sliding piece 13 to change the engagement and disengagement state of the pawl 12, and in turn the reliability of the gear shifting mechanism 5 is improved.

[0164] It can be understood that when a plurality of first gears 32 are arranged on the secondary shaft 3, the gear shifting mechanism 5 comprises a corresponding number of pawls 12, each pawl 12 is provided with an elastic piece 14, and each pawl 12 is used to control the locking and separation of the first gear 32 corresponding to the pawl 12 and the secondary shaft 3.

[0165] The axial length of the sliding piece 13 is greater than the axial length of the second shifting groove 131, and the portions of the sliding piece 13 located at two ends of the second shifting groove 131 are used to push the pawls 12 which do not need to lock the first gears 32, that is, the pawls 12 in the reset state abut against the sliding piece 13 when there is no gear shifting.

[0166] In a preferred embodiment, the gear shifting mechanism 5 further comprises a bearing 161 installed between the sliding member 13 and the nut 16 to reduce the friction between the sliding member 13 and the nut 16 when the sliding member 13 rotates relative to the nut 16.

[0167] Further, the number of bearings 161 is two, and the two bearings 161 are respectively arranged at the two ends of the nut 16. The gear shifting mechanism 5 further comprises an axial positioning member 162 arranged between the two bearings 161 to axially position the two bearings 161.

[0168] In a preferred embodiment, the edges of the second gear shifting groove 131 are provided with axial slopes, i.e. the edges are provided with slope surfaces extending in the axial direction and inclined to the inner wall surface of the second gear shifting groove and the sliding member, so that the speed of the pawl 12 exiting from the second gear shifting groove 131 can be improved, and the gear shifting speed is further improved.

[0169] In a preferred embodiment, the screw rod 15 extends to the outside of the countershaft 3 at least at one end to be connected to a driving device, so that the driving device drives the screw rod 15 to rotate.

[0170] The sliding member 13 is circumferentially rotatably sleeved on the outside of the nut 16, so that the sliding member 13 rotates synchronously with the countershaft 3, and the screw rod 15 and the nut 16 do not rotate with the countershaft.

[0171] The nut 16 can also be located at one end of the sliding member 13 and abut against the sliding member 13 to push the sliding member 13 to move in the axial direction.

[0172] In a preferred embodiment, the sliding member 13 comprises a sliding member body 132 and a boss 133 protruding from the sliding member body 132, and the boss 133 is installed in the countershaft 3 and can slide in the axial direction of the countershaft 3. For example, the inner wall of the countershaft 3 is provided with an axially extending recessed sliding groove 22, and the boss 133 is installed in the recessed sliding groove 22, so that the sliding member 13 can rotate synchronously with the countershaft 3 and can move in the axial direction under the pushing of the nut 16 to realize load shifting.

[0173] In another preferred embodiment, the sliding member 13 comprises two bosses 133 protruding from the two ends of the sliding member body 132, and the two bosses 133 are respectively installed in the two recessed sliding grooves 22 of the countershaft 3, so that the stability of the sliding member 13 during sliding is improved, and the stability of the gear shifting mechanism 5 during gear shifting is further improved.

[0174] In another preferred embodiment, the countershaft 3 is provided with a boss (not shown in the figure), and the sliding member 13 is provided with a recessed sliding groove (not shown in the figure) matched with the boss, so that the rotation of the sliding member 13 in the circumferential direction can also be limited.

[0175] In another preferred embodiment, the shift mechanism 5 further comprises a snap spring 163 arranged at both ends of the nut 16, which can limit the axial movement of the sliding member 13 on the nut 16, thereby improving the stability of the sliding member 13 during movement.

[0176] In another preferred embodiment, the first fixing member 17 comprises a plurality of fixing rods 171, both ends of which are mounted on the housing where the shift mechanism is located. For example, the housing is the housing of the mid-mounted transmission where the shift mechanism 5 is located, and both sides of the housing are provided with mounting grooves (not shown in the figure) consistent with the number of the fixing rods 171, and both ends of the fixing rods 171 are respectively mounted in the corresponding mounting grooves. Therefore, the fixing rods 171 are fixed on the housing, and the plurality of fixing rods 171 can fix the nut 16 in the circumferential direction.

[0177] Further, the plurality of fixing rods 171 are arranged through the nut 16, thereby saving the space occupied by the first fixing member 17 in the circumferential direction.

[0178] In a preferred embodiment, each first gear 32 corresponds to two pawls 12, and the two pawls 12 are respectively arranged on both sides of the radial direction of the sliding member 13, and the number of the second shift grooves 131 is correspondingly two, and each second shift groove 131 is matched with the corresponding pawl 12. Correspondingly, each pawl 12 corresponds to an elastic member 14.

[0179] When the sliding member 13 moves axially, and the two corresponding pawls 12 are respectively located above the two second shift grooves 131, the two pawls 12 are rotated under the action of the corresponding elastic members 14, i.e. one end enters the shift groove, and the other end is raised, and the two pawls 12 are respectively clamped in different clamping grooves 21 on the inner side of the first gear 32, thereby locking the first gear 32 and the countershaft 3. When the sliding member 13 moves axially to make the two corresponding pawls 12 away from the second shift grooves 131, the two pawls 12 are reset under the action of the sliding member 13, and are separated from the first gear 32, thereby realizing the separation of the first gear 32 and the countershaft 3. By arranging two second shift grooves 131 and two pawls 12 corresponding to each first gear 32, i.e. each first gear 32 is locked and separated from the countershaft 3 through the action of two pawls 12, the locking strength of the pawl 12 and the first gear 32 can be improved, and the reliability of the shift mechanism 5 can be improved.

[0180] In a preferred embodiment, as shown in FIG. 3, the gear shifting mechanism 5 further comprises a second fixing member 18, which is located outside the sliding member 13 and to which the pawl 12 is rotationally connected. In this embodiment, the second fixing member 18 is a rod, and the pawl 12 is sleeved on the second fixing member 18 and can rotate around the axis of the second fixing member 18. The second fixing member 18 can be fixed on the countershaft 3, so that the pawl 12 rotates synchronously with the countershaft 3 and can also rotate around the second fixing member 18 to realize gear engagement and gear disengagement.

[0181] In another preferred embodiment, the countershaft 3 is provided with a limiting hole 23, which is located at the same position as the first gear 32 in the axial direction of the countershaft 3. The pawl 12 and the elastic member 14 are both arranged in the limiting hole 23, so that the limiting hole 23 can limit the movement of the pawl 12 and the elastic member 14 in the axial direction, thereby stably locking the first gear 32.

[0182] Further, as shown in FIG. 2, the countershaft 3 is provided with a fixing groove 20 for mounting the second fixing member 18. The second fixing member 18 is arranged in the fixing groove 20, thereby fixing the second fixing member 18 in the axial direction and fixing the pawl 12 in the limiting hole 23.

[0183] Embodiment 2

[0184] In another preferred embodiment, the gear shifting mechanism 5 is shown in FIGS. 7 and 8, and is specifically as follows:

[0185] The gear shifting mechanism 5 comprises a sleeve 55, a pawl 12, and an elastic member 14. The sleeve 55 is arranged in the countershaft 3, and the pawl 12 and the elastic member 14 are arranged in the countershaft 3 and outside the sleeve 55. The sleeve 55 is provided with a first gear shifting groove 551, and is arranged to rotate under the driving of a driving device. When the sleeve 55 rotates to a position where the first end of the pawl 12 is above the first gear shifting groove 551, the elastic member 14 presses the first end of the pawl 12 into the first gear shifting groove 551, so that the second end of the pawl 12 is lifted to lock the countershaft 3 and the first gear 32. When the first end of the pawl 12 is away from the first gear shifting groove 551, the sleeve 55 is tangent to the pawl 12 to lift the first end of the pawl 12, and the second end of the pawl 12 is reset to separate the first gear 32 and the countershaft 3.

[0186] Specifically, the elastic member 14 is in contact with the pawl 12 and the countershaft 3 at both ends. For example, the countershaft 3 is provided with a positioning member, and the elastic member 14 is arranged on the positioning member and in contact with the pawl 12 and the countershaft 3 at both ends. Specifically, the positioning member is preferably a circular shaft such as the second fixing member 18.

[0187] The elastic member 14 applies a force to the first end of the pawl 12 towards one side of the sleeve 55. When the sleeve 55 rotates, the relative position of the pawl 12 to the first shift groove 551 changes: when the sleeve 55 rotates to the first end of the pawl 12 being above the first shift groove 551, the elastic member 14 presses against the first end of the pawl 12, causing the first end of the pawl 12 to enter the first shift groove 551, thereby causing the second end of the pawl 12 to be raised, and the raised second end of the pawl 12 engages in the clamping groove 21 on the inner side of the first gear 32, thereby locking the first gear 32 and the lay shaft 3, achieving gear engagement; when the sleeve 55 rotates to move the first end of the pawl 12 away from the first shift groove 551, the first end of the pawl 12 abuts against the sleeve 55, i.e. the sleeve 55 is tangent to the first end of the pawl 12, thereby lifting the first end of the pawl 12, and at the same time the second end of the pawl 12 resets, i.e. the second end of the pawl 12 disengages from the first gear 32, achieving disengagement of the first gear 32 and the lay shaft 3, thereby achieving gear disengagement. That is, when gear shifting is required, the relative position of the shift groove and the pawl is changed by rotating the sleeve, and the clutching and disengaging of the lay shaft 3 and the first gear 32 is achieved by the pawl. Since the sleeve 55 applies a greater force to the pawl 12 when it rotates, gear shifting can be achieved under load on the pawl 12.

[0188] At the same time, the clutching and disengaging state of the pawl 12 is changed by rotating the sleeve 55, which improves the control accuracy of the pawl 12 and thereby improves the reliability of the gear shifting mechanism 5. Through the above structural design, the pawl 12 is engaged by the elastic force of the elastic member 14 and disengaged by the pushing force of the sleeve 55, thereby achieving soft engagement and hard disengagement, improving the reliability of gear shifting.

[0189] It can be understood that when a plurality of first gears 32 are installed on the lay shaft 3, the gear shifting mechanism 5 is provided with a corresponding number of pawls 12, each pawl is provided with an elastic member 14, and each pawl 12 corresponds to a first gear 32 to control the locking and disengaging of the corresponding first gear 32 and the lay shaft 3.

[0190] It can be understood that the part of the sleeve 55 other than the first shift groove 551 is used to push against the pawl that does not need to lock the first gear 32, i.e. the pawl 12 that does not participate in gear shifting is in a reset state by abutting against the sleeve 55.

[0191] In a preferred embodiment, a plurality of pawls 12 are arranged in an axial direction along the sleeve 55, the first shift groove 551 is an inclined groove, and the center line of the first shift groove 551 is not parallel to and not perpendicular to the central axis of the sleeve 55. By rotating the sleeve 55, different pawls 12 can be positioned above the first shift groove 551, thereby achieving different clutching and disengaging states of different pawls 12.

[0192] In another preferred embodiment, the plurality of pawls 12 are arranged in axial and circumferential intervals along the sleeve 55, the first shift groove 551 is a straight groove, and a middle line of the first shift groove 551 is parallel to a middle axis of the sleeve 55. By rotating the sleeve 55, the first shift groove 551 can be rotated to below different pawls 12, so as to realize different engagement states of the different pawls 12.

[0193] In a preferred embodiment, the first shift groove 551 is an inclined groove, and the shift mechanism 5 further comprises a sliding member 13 which is axially slidably arranged in the inclined groove and in the secondary shaft 3. As an example, a boss 133 can be arranged on the sliding member 13, and the boss 133 extends into a recessed sliding groove 22 on an inner wall of the secondary shaft 3 after passing through the inclined groove. When no shifting is needed, the sliding member 13 and the sleeve 55 rotate synchronously with the secondary shaft 3. When shifting is needed, the sliding member 13 can drive the sleeve 55 to rotate relative to the secondary shaft 3 by axial movement.

[0194] Specifically, since the sliding member 13 passes through the inclined groove, when the sliding member 13 moves axially, the movement of the sliding member 13 in the inclined groove drives the sleeve 55 to rotate. Therefore, when shifting is needed, the sleeve 55 can be driven to rotate relative to the secondary shaft 3 by axially moving the sliding member 13, so as to change the relative position of the inclined groove and the pawl 12 and realize shifting. The secondary shaft 3 limits the sliding member 13 in the circumferential direction, so that the sliding member 13 can rotate synchronously with the secondary shaft 3. Therefore, when no shifting is needed, the sliding member 13 does not move axially, but drives the sleeve 55 to rotate synchronously with the secondary shaft 3. Since the pawl 12 and the elastic member 14 are arranged in the secondary shaft 3, the pawl 12 and the elastic member 14 also rotate synchronously with the secondary shaft 3.

[0195] As described above, by passing the sliding member 13 through the inclined groove, the axial movement of the sliding member 13 can be converted into the circumferential rotation of the sleeve 55. In this way, the driving device of the sliding member 13 only needs to realize the axial movement of the sliding member 13, which is convenient for simplifying the structure of the driving device.

[0196] Further preferably, an edge of the first shift groove 551 is provided with a slope surface which extends in a vertical direction of a middle line of the shift groove 11. The slope surface is inclined from an outer side of the first shift groove 551 to the middle line direction, so as to accelerate the speed of the pawl 12 exiting from the first shift groove 551, and further improve the speed of shifting down.

[0197] Further preferably, the gear shift mechanism 5 further comprises a screw rod 15, a nut 16 and a first fixing member 17, the nut 16 is installed on the screw rod 15, the first fixing member 17 limits the nut 16 in the circumferential direction, the screw rod 15 drives the nut 16 to move along the axial direction of the screw rod 15 by rotating, so as to drive the sliding member 13 to move along the axial direction of the screw rod 15. Specifically, since the nut 16 cannot rotate in the circumferential direction, when the screw rod 15 rotates, the nut 16 can only move along the axial direction, and the nut 16 limits the sliding member 13 in the axial direction. Therefore, the sliding member 13 can be pushed to move along the axial direction when the nut 16 moves along the axial direction.

[0198] The sliding member 13 is circumferentially rotatably sleeved on the nut 16, so that the sliding member 13 can rotate synchronously with the countershaft 3 while being axially moved under the driving of the nut 16, and the structure mode of radial concave-convex sliding grooves between the wall surfaces of the two can be used to achieve this, of course, other alternative structures can also be used, which will not be described one by one here.

[0199] The screw rod 15 extends to the outside of the countershaft 3 at least at one end, which is used to be connected with a driving device to drive the screw rod 15 to rotate.

[0200] The first fixing member 17 comprises a plurality of fixing rods 171, both ends of the fixing rod 171 are installed on the housing where the gear shift mechanism is located. For example, the housing is the housing of the mid-mounted transmission where the gear shift mechanism is located, both sides of the housing are provided with mounting grooves (not shown in the figure) consistent with the number of the fixing rods 171, and the fixing rods 171 are embedded in the mounting grooves. Therefore, the fixing rods 171 are fixed on the housing, and the plurality of fixing rods 171 can circumferentially fix the nut 16.

[0201] The plurality of fixing rods 171 are arranged at intervals along the circumference of the nut 16 and respectively penetrate the nut 16, so that the occupied space of the first fixing member 17 in the circumferential direction can be saved, and the volume of the gear shift mechanism can be reduced.

[0202] In a preferred embodiment, each first gear 32 corresponds to two pawls 12, the two pawls 12 are respectively arranged on both sides of the sleeve 55 and are matched with the corresponding first shift groove 551, and the number of the first shift groove 551 on the sleeve 55 is 2. Correspondingly, each pawl 12 corresponds to an elastic member 14. When the sleeve 55 rotates, the two corresponding pawls 12 are respectively located above the corresponding first shift groove 551, and the two pawls 12 are respectively rotated under the action of the corresponding elastic member 14, that is, the first end of the pawl 12 enters the first shift groove 551, and the second end is raised, and the two pawls 12 are respectively clamped in the two clamping grooves 21 on the inner side of the corresponding first gear 32, so as to lock the first gear 32 and the lay shaft 3. When the first end of the two corresponding pawls 12 is away from the first shift groove 551, the two pawls 12 are simultaneously reset under the action of the sleeve 55 and are separated from the first gear 32, so as to separate the first gear 32 from the lay shaft 3. By arranging two first shift grooves 551 and two pawls 12 corresponding to each first gear 32, the locking strength of the pawl 12 and the first gear 32 can be improved, and the shift reliability of the shift mechanism 5 can be improved.

[0203] In a preferred embodiment, the number of the first shift groove 551 is 2, and the two ends of the sliding member 13 are respectively arranged in the two first shift grooves 551. For example, the sliding member 13 includes a mounting portion and a boss protruding from both ends of the mounting portion, the shape of the mounting portion can be a circular ring shape, the mounting portion is sleeved on the nut 16, the two bosses are respectively arranged in the two first shift grooves 551, and the two bosses are respectively arranged in the grooves of the shaft 20, so that the stability of the sliding member 13 during sliding can be improved, and the stability of the shift mechanism 5 during shifting can be improved.

[0204] In a preferred embodiment, the shift mechanism 5 further includes a second fixing member 18, the second fixing member 18 is located outside the sleeve 55, and the pawl 12 is circumferentially rotatably arranged on the second fixing member 18; the lay shaft 3 is provided with a limiting hole 23 for axially limiting the movement of the pawl 12 and the elastic member 14. It should be noted that the mounting and fixing mode of the second fixing member and the limiting hole are the same as described in Embodiment 1, and will not be repeated here.

[0205] In an embodiment, the shift mechanism 5 further includes a planetary gear assembly for driving the sleeve 55 to rotate. The output end of the planetary gear assembly can be connected with the sleeve 55, so that the planetary gear assembly directly drives the sleeve 55 to rotate; or the screw rod 15 can be connected with the output end of the planetary gear assembly, so that the planetary gear assembly drives the sleeve 55 to rotate by rotating the screw rod 15.

[0206] Embodiment 3

[0207] As shown in Fig. 9, the transmission mechanism 4 is a gear transmission, which comprises a first gear set 41 and a second gear set 42. The first gear set 41 comprises a first driving gear 411 and a first driven gear 412 which are engaged with each other. The first driving gear 411 is fixedly connected with the middle shaft 2, and the first driven gear 412 is fixedly connected with the auxiliary shaft 3. It should be noted that the fixed connection herein refers to a connection mode which can realize synchronous rotation of the gear and the shaft, including but not limited to welding connection, concave-convex groove matching connection, key connection, etc.

[0208] The first driving gear 411 is driven to rotate by the middle shaft 2, and in turn drives the first driven gear 412 to rotate the auxiliary shaft 3. In the embodiment, the number of teeth of the first driving gear 411 is greater than that of the first driven gear 412, so that the transmission ratio of the first gear set 41 is less than 1, which is a speed-increasing transmission.

[0209] The torque of the auxiliary shaft 3 is transmitted to the second gear set 42. The second gear set 42 comprises a second driving gear 421 and a second driven gear 422 which are engaged with each other. The second driving gear 421 is movably connected with the auxiliary shaft 3, and the second driven gear 422 is fixedly connected with a transmission sleeve 91. The transmission sleeve 91 is movably connected with the middle shaft 2. The second driving gear 421 is relatively fixed or relatively movable with the auxiliary shaft 3 by the shift mechanism 5 to perform gear shifting. The transmission sleeve 91 and a front sprocket 92 are collectively referred to as an output assembly 9.

[0210] Both the second driving gear 421 and the second driven gear 422 are provided with a plurality of gears. In the embodiment, the second gear set 42 is provided with seven second driving gears 421 and seven second driven gears 422. As shown in Figs. 10 and 11, the number of teeth of the second driving gears 421 decreases step by step from left to right, and correspondingly, the number of teeth of the second driven gears 422 increases step by step from left to right. Therefore, the second gear set 42 can be a speed-increasing transmission or a speed-reducing transmission. The transmission has seven gear positions.

[0211] In order to realize gear shifting, the shift mechanism 5 is provided. The shift mechanism 5 can fix one of the six second driving gears 421 with the auxiliary shaft 3.

[0212] As shown in Figs. 12 to 16, the shift mechanism 5 comprises a reset member 52, a rotary control member 53 and at least two pawls 51. A recess 31 is formed on the auxiliary shaft 3 along the circumferential direction thereof. A second fixing member 18 is installed in the recess 31. The pawls 51 are rotatably installed in the recess 31 in sequence behind the second fixing member 18 along the axial direction of the auxiliary shaft 3. The outer diameter of the rotary control member 53 is smaller than the inner diameter of the auxiliary shaft 3. The rotary control member 53 is hollow.

[0213] As shown in FIG. 13, the pawl 51 has a locking portion 511, a control portion 512, an extension portion 513 and a pivot portion 514. The pivot portion 514 is a circular through hole, and a pivot passes through the pivot portion 514 to make the pawl 51 sleeved on the second fixing member 18, so that the pawl 51 can rotate axially around the second fixing member 18. The control portion 512 and the locking portion 511 of the pawl 51 are both protruded along the thickness direction of the pawl 51, and the control portion 512 is located on the side opposite to the locking portion 511. The locking portion 511 is used for locking or disengaging with the gear in the transmission mechanism 4. The locking portion 511 is located above the control portion 512. The extension portion 513 has a rectangular cross section. The control portion 512 and the locking portion 511 are connected through the extension portion 513. The extension portion 513 plays a connecting role, so that the locking portion 511 of the pawl 51 is located outside the rotation control member 53, and the control portion 512 of the pawl 51 is located inside the rotation control member 53. Since the rotation control member 53 is hollow, it has a larger space to accommodate the control portion 512. The control portion 512 can be provided with a more reasonable structure, that is, a more wear-resistant structure, so that the service life is longer.

[0214] Specifically, the control portion 512 is protruded from the extension portion 513 with a triangular cross section. The pointed top structure of the control portion 512 is more likely to fall into the control groove 531 than other planar or arc structures, so that the gear shifting is more sensitive. In order to further increase the wear resistance of the control portion 512, a round corner is arranged at the position where the control portion 512 contacts with the inner circumferential surface of the rotation control member 53. In this embodiment, the control portion 512 has a pointed top structure at the position where it contacts with the inner circumferential surface of the rotation control member 53. If the pointed top structure contacts with the inner circumferential surface of the rotation control member 53, a point contact will be formed, the contact area is small, and it is easy to wear. After being provided with a round corner, the point contact becomes a line contact, the contact area is increased, and the pawl 51 is more wear-resistant.

[0215] As shown in FIG. 14, the outer circumferential surface of the rotation control member 53 is provided with a control groove 531. The control groove 531 is opened along the circumferential direction of the rotation control member 53. The arrangement angles of the control grooves 531 of different gears are different. The outer circumferential surface of the rotation control member 53 is also provided with an avoiding groove 532. The avoiding groove 532 is also opened along the circumferential direction of the rotation control member 53. The avoiding groove 532 is located on one side of the control groove 531 and communicates with the control groove 531. The length of the avoiding groove 532 is longer than that of the control groove 531. The extension portion 513 of the pawl 51 passes through the avoiding groove 532 to connect the control portion 512 and the locking portion 511 respectively.

[0216] One end of the reset member 52 abuts against the secondary shaft 3, and the other end of the reset member 52 abuts against one end of the pawl 51. The reset member 52 can press the one end of the pawl 51 to be lower, so that the control portion 512 located at the other end of the pawl 51 keeps abutting against the inner circumferential surface of the rotation control member 53. It should be noted that the rotation control member 53 is not static, but rotates synchronously with the secondary shaft 3.

[0217] As shown in Fig. 16, when the rotation control member 53 is deflected with the rotation angle of the secondary shaft 3, the pawl 51 is lifted at one end to enter the control groove 531, and the locking portion 511 of the pawl 51 is clamped into the locking groove 4211 of the second driving gear 421, so that the second driving gear 421 of the transmission mechanism 4 is fixed with the secondary shaft 3, and the transmission ratio can be changed.

[0218] If the control portion 512 is arranged at the side of the locking portion 511, the width of the control groove 531 will inevitably increase, and under the premise that the width of the rotation control member 53 remains unchanged, the number of the control grooves 531 will decrease, and the gear position will also decrease. In order to avoid the above situation, the locking portion 511 and the control portion 512 can be arranged on the same radial plane, where the radial direction refers to the radial direction of the pawl 51. In this way, the locking portion 511 and the control portion 512 will have an overlapping area in the radial plane. Part of the control portion 512 is in the avoiding groove 532, and the other part is in the control groove 531, so that the width of the control groove 531 can be kept within a reasonable range.

[0219] In the present embodiment, six pawls 51 are arranged, one of the second driving gears 421 with the smallest number of teeth is fixed with the secondary shaft 3, and a one-way clutch 93 is arranged between one of the second driving gears 421 with the largest number of teeth and the transmission sleeve 91. This design can save the pawl 51 arranged to control the one of the second driving gears 421 with the smallest number of teeth. The principle is that:

[0220] When all the pawls 51 do not fall into the control groove 531 of the rotation control member 53, the one-way clutch 93 is engaged, and the one of the second driving gears 421 with the smallest number of teeth is engaged with the one of the second driving gears 422 with the largest number of teeth for transmission; when one of the pawls 51 falls into the control groove 531 of the rotation control member 53, the one of the second driving gears 421 with the smallest number of teeth is fixed with the secondary shaft 3, the rotation speed of the transmission sleeve 91 is higher than that of the one of the second driving gears 422 with the largest number of teeth, and the one-way clutch 93 is disengaged.

[0221] The one-way clutch 93 can be a roller clutch, a wedge clutch, a pawl clutch, a friction clutch, an electromagnetic clutch, etc.

[0222] The rotation control member 53 of the gear shifting mechanism 5 can be directly controlled by the driving device 6, but the driving device 6 needs to collect the rotation speed of the secondary shaft 3 and always keep the same rotation speed as the rotation control member 53, which will cause a large power consumption.

[0223] In order to facilitate the control of the rotating control member 53, a rotational speed mixing mechanism 7 is arranged. As shown in Figs. 17 to 19, the rotational speed mixing mechanism 7 is connected with the shift mechanism 5, the countershaft 3 and the driving device 6 respectively, when the driving device 6 does not perform the shift operation, that is, the driving device 6 does not input torque to the rotational speed mixing mechanism 7, the rotational speed mixing mechanism 7 synchronizes the rotation of the rotating control member 53 of the shift mechanism 5 and the countershaft 3; when the driving device 6 performs the shift operation, the rotational speed mixing mechanism 7 makes the rotating control member 53 of the shift mechanism 5 and the countershaft 3 have a deviation in the rotation angle.

[0224] The rotational speed mixing mechanism 7 comprises a first ring gear 71, a first sun gear 72, a planet carrier 73, a multiple planetary gear 74, a second ring gear 76 and a second sun gear 75, the multiple planetary gear 74 is rotatably connected to the planet carrier 73, the multiple planetary gear 74 is engaged with the first ring gear 71, the first sun gear 72, the second ring gear 76 and the second sun gear 75 respectively, the first ring gear 71 is connected with the rotating control member 53 of the shift mechanism 5, the second ring gear 76 is connected with the countershaft 3, the first sun gear 72 is connected with the driving device 6, and the second sun gear 75 is connected with the housing 1.

[0225] The first ring gear 71 and the rotating control member 53 can be separate or integrated, the separate one is more convenient to process, and the integrated one has higher structural strength, in the case shown in Fig. 14, the first ring gear 71 and the rotating control member 53 are integrally formed.

[0226] As shown in Fig. 19, the multiple planetary gear 74 is a double planetary gear 741, which comprises first and second planetary gears 7411 and 7412 having the same number of teeth, the first planetary gear 7411 is engaged with the first ring gear 71 and the first sun gear 72 respectively, and the second planetary gear 742 is engaged with the second ring gear 76 and the second sun gear 75 respectively. The double planetary gear 741 has simple structure and is convenient to assemble, and since the transmission of the rotational speed mixing mechanism 7 is relatively small, the driving device 6 needs to select a larger torque type.

[0227] When the shift operation is not performed, that is, the driving device 6 does not rotate, since the output shaft of the driving device 6 itself has a certain resistance, the first sun gear 72 is equivalent to be fixed, and since the first and second planetary gears 7411 and 7412 of the double planetary gear 741 have the same number of teeth, the rotating control member 53 will be driven by the countershaft 3 and rotate at the same rotation direction and the same rotation speed.

[0228] When the shift operation needs to be performed, the driving device 6 rotates forward or reversely for a certain number of turns, and the rotation speed of the countershaft 3 and the rotation speed of the first sun gear 72 are mixed and output to the rotation control member 53. Specifically, when the rotation speed of the first sun gear 72 and the rotation speed of the countershaft 3 are in the same direction, the rotation speed of the rotation control member 53 is the sum of the rotation speed of the countershaft 3 and the rotation speed of the first sun gear 72; when the rotation speed of the first sun gear 72 and the rotation speed of the countershaft 3 are in opposite directions, the rotation speed of the rotation control member 53 is the difference between the rotation speed of the countershaft 3 and the rotation speed of the first sun gear 72. After the shift operation is performed, the rotation control member 53 again rotates synchronously with the countershaft 3.

[0229] The driving device 6 is a shift motor, which is preferably an encoder motor. The encoder motor can obtain real-time position, speed, and angle information of motor movement through an encoder, and has high measurement accuracy and accuracy, and is suitable for application scenarios with high requirements for position, speed, and angle. The shift motor is fixedly connected to the housing 1, and the shift motor does not need to rotate with the countershaft 3, avoiding the power supply problem of the shift motor and reducing the maintenance difficulty.

[0230] It should be noted that since the control part 512 of the pawl 51 is arranged in the rotation control member 53, there is no space to place the driving device 6, so the driving device 6 needs to be arranged on one side of the rotation control member 53. The driving device 6 needs to be connected with the first sun gear 72, but there is a second sun gear 75 between the driving device 6 and the first sun gear 72, so the center of the second sun gear 75 needs to be provided with a through hole, so that the output shaft of the driving device 6 is connected with the first sun gear 72.

[0231] Embodiment 4

[0232] Ebike is the abbreviation of Electric Bike, also known as electric-assisted bicycle, which is a kind of bicycle that uses battery and electric motor to provide auxiliary power. Unlike traditional bicycles, Ebike uses battery and electric motor to provide auxiliary power, making riding more comfortable and convenient.

[0233] The electric motor is usually installed in the middle of the wheel or the frame, and can supply the required electric energy through the battery. The electric motor installed in the wheel is generally called rear motor, and the electric motor installed in the middle of the frame is generally called middle motor. The electric motor of Ebike adopts a direct-current brushless motor, which can be divided into 250W, 350W, 500W, etc. according to different power levels.

[0234] The Chinese patent document CN117341882A discloses a bicycle middle box type power-assisted variable speed motor, wherein the variable speed driving device comprises a gear piece, an L-shaped pull rod, a pull rod shaft, a return spring, a pull rod distribution gear, a driving roller, a cam cover, a bearing, a micro gear motor and a position sensor.

[0235] In the embodiment, the driving device 6 of the middle transmission is arranged inside the secondary shaft 3, the space inside the secondary shaft 3 is reasonably utilized, and the entire middle transmission becomes more compact, and the volume of the entire middle transmission can be reduced.

[0236] In the embodiment, the transmission mechanism 4 is a gear transmission, as shown in FIGS. 9, 11 and 21, and the specific structure of the transmission mechanism 4 is the same as that in the embodiment 3, and the related description in the embodiment 3 can be referred to, which will not be repeated here.

[0237] In order to realize gear shifting, the gear shifting mechanism 5 is arranged, and the gear shifting mechanism 5 can fix one of the six second driving gears 421 with the secondary shaft 3.

[0238] As shown in FIGS. 22 and 23, the gear shifting mechanism 5 comprises a return member 52, a rotary control member 53 and at least two pawls 51, the secondary shaft 3 is provided with a groove 31 along the circumferential direction, the second fixing member 18 is arranged in the groove 31, the pawl 51 is rotatably arranged in the groove 31 after being sequentially sleeved on the second fixing member 18 along the axial direction of the secondary shaft 3, the outer diameter of the rotary control member 53 is smaller than the inner diameter of the secondary shaft 3, and the rotary control member 53 is hollow.

[0239] The outer circumferential surface of the rotary control member 53 is provided with a control groove 531, and the pawl 51 is arranged outside the rotary control member 53. One end of the return member 52 abuts against the secondary shaft 3, and the other end of the return member 52 abuts against one end of the pawl 51. The return member 52 can press the one end of the pawl 51 down to abut against the outer circumferential surface of the rotary control member 53. It should be noted that the rotary control member 53 is not static, and the rotary control member 53 rotates synchronously with the secondary shaft 3.

[0240] As shown in FIG. 24, when the rotary angle of the rotary control member 53 deviates from the secondary shaft 3, one end of the pawl 51 enters the control groove 531, and the other end of the pawl 51 is popped up to be clamped in the locking groove 4211 of the second driving gear 421, so that the second driving gear 421 of the transmission mechanism 4 is fixed with the secondary shaft 3 to change the transmission ratio.

[0241] In a preferred embodiment, as shown in FIG. 23, the control groove 531 is a spiral groove 5311, which is convenient to process and can be processed by a numerical control lathe or electric spark machining.

[0242] In another preferred embodiment, as shown in FIG. 25, the control groove 531 comprises at least two through grooves 5312 arranged in a spiral shape on the outer circumferential surface of the rotation control member 53, the cross section of the through groove 5312 is rectangular, the length and width of the cross section are adapted to the length and width of the pawl 51 respectively, the through groove 5312 is opened along the circumferential direction of the rotation control member 53, and adjacent two through grooves 5312 are not communicated. When one end of the pawl 51 falls into the control groove 531, the groove wall of the through groove 5312 will limit the axial movement of the end of the pawl 51, avoiding the action force of the gear pair of the transmission mechanism 4 on the pawl 51 to make the other end of the pawl 51 out of the locking groove 4211 of the second driving gear 421, ensuring that there is no jump shift, and ensuring the accuracy and stability of the shift.

[0243] The control groove 531 is opened along the circumferential direction of the rotation control member 53, and the arrangement angles of the control grooves 531 of different gears are different. The outer circumferential surface of the rotation control member 53 is further provided with an avoiding groove 532, the avoiding groove 532 is opened along the circumferential direction of the rotation control member 53, the avoiding groove 532 is on one side of the control groove 531 and communicated with the control groove 531, and the length of the avoiding groove 532 is longer than that of the control groove 531. The extension part 513 of the pawl 51 passes through the avoiding groove 532 and is connected with the control part 512 and the locking part 511 respectively.

[0244] The second driving gear 421 and the second driven gear 422 are both provided with a plurality of, as shown in FIG. 21, in this embodiment, six pawls 51 are provided, one of the second driving gears 421 with the smallest number of teeth is fixed with the lay shaft 3, and one of the second driven gears 422 with the largest number of teeth is provided with a one-way clutch 93 between the transmission sleeve 91, this design can save the pawl 51 for controlling the one of the second driving gears 421 with the smallest number of teeth, the principle is the same as that in embodiment 3, and thus will not be described herein.

[0245] The one-way clutch 93 can adopt a roller clutch, a wedge block clutch, a pawl clutch, a friction clutch, an electromagnetic clutch, etc.

[0246] Since the lay shaft 3 and the rotation control member 53 are both hollow, in order to reasonably utilize the space in the lay shaft 3, make the whole mid-mounted transmission more compact, and reduce the volume of the whole mid-mounted transmission, the driving device 6 is hidden inside the lay shaft 3, and the positional relationship between the driving device 6 and the lay shaft 3 and the shift mechanism 5 is that the rotation control member 53 is arranged inside the lay shaft 3, and the driving device 6 is arranged inside the rotation control member 53.

[0247] The rotation control member 53 of the shift mechanism 5 can be directly controlled by the driving device 6, but the driving device 6 needs to collect the rotating speed of the lay shaft 3 and always keep the same rotating speed as the rotation control member 53, which will cause great power consumption.

[0248] In order to facilitate the control of the rotating control member 53, a rotational speed mixing mechanism 7 is provided. As shown in FIG. 21, the rotational speed mixing mechanism 7 is connected with the shift mechanism 5, the countershaft 3 and the driving device 6 respectively. When the driving device 6 does not perform the shift operation, i.e. the driving device 6 does not input torque to the rotational speed mixing mechanism 7, the rotational speed mixing mechanism 7 synchronizes the rotation of the rotating control member 53 of the shift mechanism 5 and the countershaft 3. When the driving device 6 performs the shift operation, the rotational speed mixing mechanism 7 causes the rotating control member 53 of the shift mechanism 5 and the countershaft 3 to have a deviation in the rotation angle.

[0249] A preferred embodiment of the rotational speed mixing mechanism 7 is the same as that in Embodiment 3, and the specific structure is shown in FIGS. 17 and 18, which will not be described herein.

[0250] In the embodiment shown in FIG. 25, the first ring gear 71 is integrally formed with the rotating control member 53. In other embodiments, the first ring gear 71 and the rotating control member 53 can be separately formed. The separately formed structure is more convenient to process, and the integrally formed structure has higher part strength.

[0251] The multiple planetary gears 74 can be double planetary gears, triple planetary gears or more. The more planetary gears, the greater transmission ratio the rotational speed mixing mechanism 7 can obtain. The greater transmission ratio of the rotational speed mixing mechanism 7, the smaller torque the driving device 6 needs to provide under the same load.

[0252] In a preferred embodiment, as shown in FIG. 26, the multiple planetary gears 74 are double planetary gears 741. The structure of the double planetary gears 741 is described in Embodiment 3, which will not be described herein.

[0253] In another preferred embodiment, as shown in FIG. 27, the multiple planetary gears 74 are quadruple planetary gears 742. The quadruple planetary gears 742 include third planetary gears 7421 and sixth planetary gears 7424 which have the same number of teeth, and fourth planetary gears 7422 and fifth planetary gears 7423 which have the same number of teeth. The third planetary gears 7421 have a smaller number of teeth than the fourth planetary gears 7422. The third planetary gears 7421 are engaged with the first ring gear 71. The fourth planetary gears 7422 are engaged with the first sun gear 72. The sixth planetary gears 7424 are engaged with the second ring gear 76. The fifth planetary gears 7423 are engaged with the second sun gear 75. Compared with the double planetary gears 741, the quadruple planetary gears 742 can make the rotational speed mixing mechanism 7 obtain a greater transmission ratio. Then, the driving device 6 can be selected to be of a small torque type. The driving device 6 of the small torque type has a smaller size, which can further reduce the space of the mid-mounted transmission. Alternatively, the driving device 6 can be selected to be of a large torque type, which has a longer service life.

[0254] When no shifting operation is performed, i.e. the driving device 6 does not rotate, the first sun gear 72 is equivalent to a fixed gear due to the resistance of the output shaft of the driving device 6 itself, and the first planetary gear 7411 and the second planetary gear 7412 of the double planetary gear 741 or the third planetary gear 7421 and the sixth planetary gear 7424 of the quadruple planetary gear 742 have the same number of teeth, so the rotation control member 53 will be driven by the countershaft 3 and kept rotating at the same rotational direction and the same rotational speed.

[0255] When the shifting operation is needed, the driving device 6 rotates in a certain number of revolutions in the forward direction or in the reverse direction, and the rotational speed of the countershaft 3 and the rotational speed of the first sun gear 72 will be mixed and output to the rotation control member 53. Specifically, when the rotational speed of the first sun gear 72 and the rotational speed of the countershaft 3 are in the same direction, the rotational speed of the rotation control member 53 is the sum of the rotational speed of the countershaft 3 and the rotational speed of the first sun gear 72; when the rotational speed of the first sun gear 72 and the rotational speed of the countershaft 3 are in opposite directions, the rotational speed of the rotation control member 53 is the difference between the rotational speed of the countershaft 3 and the rotational speed of the first sun gear 72. After the shifting operation is performed, the rotation control member 53 again keeps rotating synchronously with the countershaft 3.

[0256] The driving device 6 is a shifting motor, which is preferably an encoder motor. The encoder motor can obtain real-time position, speed and angle information of the motor movement through an encoder, and has high measurement accuracy and accuracy, and is suitable for application scenarios with high requirements for position, speed and angle. The shifting motor is fixedly connected to the housing 1, and the shifting motor does not need to rotate with the countershaft 3, which avoids the power supply problem of the shifting motor and reduces the maintenance difficulty.

[0257] The shifting motor is a high-speed and low-torque micro motor, which needs to rotate a large number of revolutions to drive the rotation control member 53 to rotate by a certain angle, which is not conducive to setting a sensor to obtain gear position information. Therefore, a gear position feedback device 13 is arranged to obtain the gear position information. FIG. 28 is a schematic diagram of the rotational speed mixing mechanism 7 and the gear position feedback device 13.

[0258] As shown in FIG. 29, the gear position feedback device 13 includes a plurality of rows of Hall elements 131 and magnets 133. The driving device 6 is connected with the driving device speed reduction mechanism 12, which is used to convert the high rotational speed of the driving device 6 into a low rotational speed of the output end of the driving device speed reduction mechanism 12. It should be noted that the driving device speed reduction mechanism 12 only idles and does not output torque when the driving device 6 is working. The Hall element 131 is used to sense the magnetic field strength of the magnet 133 to obtain a pulse signal and determine the gear position to which the shifting mechanism 5 rotates.

[0259] The driving device reduction mechanism 12 comprises a reduction sun gear 121, a reduction planetary gear 122, a reduction planet carrier 123 and a reduction ring gear 124, the reduction planetary gear 122 is rotatably installed on the reduction planet carrier 123, the reduction planetary gear 122 is respectively meshed with the reduction sun gear 121 and the reduction ring gear 124, the reduction sun gear 121 is fixedly connected to the driving device 6, the magnet 133 is arranged on the reduction ring gear 124, and the reduction planet carrier 123 is fixedly connected with the shell 1. The reduction sun gear 121 serves as an input end of the driving device reduction mechanism 12, and the reduction ring gear 124 serves as an output end of the driving device reduction mechanism 12, and the rotation speed of the reduction ring gear 124 is the rotation speed of the reduction sun gear 121 divided by the transmission ratio of the driving device reduction mechanism 12.

[0260] The plurality of Hall elements 131 are welded on the circuit board 132 along the circumference of the driving device reduction mechanism 12 at equal intervals. In the embodiment, the transmission has seven gears, and therefore seven Hall elements 131 are arranged correspondingly. The pulse signal obtained by the uppermost Hall element 131 and the magnet 133 is defined as gear one, and the other Hall elements 131 are sequentially defined as gear two to gear seven in the counterclockwise order.

[0261] When the gear shifting mechanism 5 performs the gear shifting operation, the driving device 6 simultaneously drives the gear shifting mechanism 5, the rotation speed mixing mechanism 7 and the driving device reduction mechanism 12 to rotate, the reduction ring gear 124 of the driving device reduction mechanism 12 rotates counterclockwise, and the rotation angle is to the relative position of the magnet 133 arranged on the reduction ring gear 124 and the Hall element 131 corresponding to gear three, and then it is judged that the gear shifted to by the gear shifting mechanism 5 is gear three. The other gears are the same.

[0262] In order to facilitate the arrangement of the gear feedback device 13, the maximum angle of the plurality of Hall elements 131 arranged in a row is not more than 360 degrees, that is, the angle between the Hall element 131 corresponding to gear one and the Hall element 131 corresponding to gear seven is the maximum angle, and the maximum angle is not more than 360 degrees, so that the design and installation of the circuit board 132 are more reasonable, and the complexity of the gear feedback device 13 is also reduced. In FIG. 29, the Hall elements 131 are arranged along the circumference of the reduction ring gear 124, and in addition, the Hall elements 131 can also be arranged along the axis of the reduction ring gear 124.

[0263] Based on the embodiments 3 or 4, a mid-drive motor is further provided, which comprises the above-mentioned transmission of the embodiments 3 or 4, so that the mid-drive motor has both gear shifting function and electric assist function. As shown in FIG. 20 or 30, the difference from the transmission is that the assist motor 10 and the assist motor reduction mechanism 11 are additionally arranged, the assist motor 10 is connected with the transmission mechanism 4, specifically, the axis of the output shaft of the assist motor 10 is parallel to the axis of the middle shaft 2, and the assist motor 10 is connected with the first gear set 41 of the transmission mechanism 4 through the assist motor reduction mechanism 11.

[0264] When the assist motor 10 is working, in addition to the torque generated by the rider pedaling, there is also the torque generated by the assist motor 10. The combined torque of the two is output to the front sprocket 92, enabling the rider to achieve higher riding speed or longer riding distance in a less strenuous way.

[0265] A mid-drive motor with shifting function, compared to a rear-drive motor (hub motor) with shifting function, has a shifting structure on the frame instead of the rear wheel. When impacted on rough roads, the impact is not directly transmitted to the hub through the rim and spokes, but is transmitted through the frame. The frame has a certain vibration absorption function, which greatly reduces the impact force. It is relatively less affected by external forces and less prone to bumps, making the mid-drive motor more durable.

[0266] Furthermore, vehicles equipped with a mid-drive motor are also equipped with a speed feedback system. For example, a GPS chip is added to obtain location information and calculate the vehicle's speed. In automatic mode, the rider does not need to operate the vehicle; the mid-drive gearbox performs gear shifting operations based on the vehicle's speed. For instance, when the vehicle speed reaches 10 kilometers per hour, it automatically shifts from first to second gear; conversely, when the vehicle speed drops below 10 kilometers per hour, it automatically shifts from second to first gear. Riders can switch to manual mode to freely change gears according to actual road conditions, increasing riding flexibility, or switch to free mode for automatic gear shifting, improving riding comfort.

[0267] Alternatively, the mid-mounted motor can have built-in cadence and torque sensors to obtain the magnitude of the rider's pedaling torque and the speed of pedaling. Based on internal algorithms, it can comprehensively determine whether the rider is in an uphill state, a state of rapid acceleration and deceleration on flat ground, a state of gentle acceleration and deceleration on flat ground, or a state of downhill, and automatically control the drive device 6 to shift gears, thus achieving the effect of automatic gear shifting.

[0268] Example 5

[0269] Those skilled in the art should know that mid-mounted transmissions typically output torque through the front sprocket to drive the wheels. Therefore, connecting the front sprocket 92 to the transmission mechanism 4 is a well-known technical means in the art, and can be found in the relevant descriptions of other embodiments, which will not be repeated here.

[0270] As shown in FIG. 31 and FIG. 32, the transmission mechanism of the mid-mounted transmission includes a plurality of first gears 32 rotatably mounted on the countershaft 3, and each first gear 32 has different outer diameter size. The inner ring side of each first gear 32 is provided with a clamping groove 21 matched with the shift mechanism 5, and when the shift mechanism 5 is locked with the clamping groove 21, the countershaft 3 is locked with the first gear 32, and the countershaft 3 and the first gear 32 are synchronously rotated. Different first gears 32 correspond to different transmission paths, and different transmission paths correspond to different ratios of input speed and output speed of the mid-mounted transmission. The shift mechanism 5 can make the countershaft 3 and the different first gears 32 synchronously rotate by switching different first gears 32, so as to change the transmission path of the mid-mounted transmission and realize the gear shifting of the mid-mounted transmission. The gear shifting is realized by gear shifting, and the state that the countershaft 3 is locked with the first gear 32 is the gear engagement state, and the state that the countershaft 3 is separated from the first gear 32 is the gear disengagement state.

[0271] As shown in FIG. 32 to FIG. 37, the shift mechanism 5 includes a sleeve 55, a pawl 12 and an elastic member 14, the sleeve 55 is provided with a first shift groove 551; the elastic member 14 is used to drive the first end of the pawl 12 to enter the first shift groove 551 and the second end of the pawl 12 to be raised when the first end of the pawl 12 is located above the first shift groove 551, so as to lock the first gear 32 located outside the sleeve 55;

[0272] The pawl 12 includes a first inclined surface 121, and the first inclined surface 121 is used to abut against the edge of the first shift groove 551 and slide when one end of the pawl 12 enters the first shift groove 551; the shape of the edge of the first shift groove 551 is a spiral surface around the center axis of the sleeve 55, and the included angle between the tangent line of the spiral line around the center axis in the spiral surface and the first inclined surface 121 at the first contact point is less than 10 degrees, and the first contact point is the contact point between the first inclined surface 121 and the spiral line. When there is an interaction force between the first inclined surface and the spiral surface, the spiral surface and the first inclined surface are deformed, and since the included angle between the tangent line of the spiral line at the first contact point and the first inclined surface is small, the contact area between the spiral surface and the first inclined surface is larger, so that the contact area between the pawl and the sleeve is increased and the local stress of the pawl is reduced during gear shifting, thereby reducing the abrasion of the pawl.

[0273] Specifically, the sleeve 55 and the pawl 12 move relatively, when the first end of the pawl 12 is above the first shift groove 551, the first inclined surface 121 is above the first shift groove 551 and contacts the edge of the first shift groove 551. The elastic member 14 exerts a force on the first end of the pawl 12, when the sleeve 55 and the pawl 12 continue to move relatively, the first inclined surface 121 abuts against the edge of the first shift groove 551 and slides, when the first inclined surface 121 is away from the edge of the first shift groove 551, the first end of the pawl 12 enters the first shift groove 551, and the second end of the pawl 12 is lifted. When the sleeve 55 and the pawl 12 move relatively, there is an interaction force between the sleeve 55 and the pawl 12, and the force point of the force exerted by the sleeve 55 on the pawl 12 is the contact point of the sleeve 55 and the first inclined surface 121. The first inclined surface 121 is composed of a plurality of helical lines, different helical lines correspond to different directions of curvature, and the contact point of the helical line around the central axis and the first inclined surface 121 is the first contact point. When the tangent line of the helical line around the central axis at the first contact point and the first inclined surface 121 form an angle less than 10 degrees, the tangent line of the helical line around the central axis at the first contact point and the first inclined surface 121 are nearly parallel, and the helical surface and the first inclined surface 121 are nearly parallel. Preferably, the tangent line of the helical line around the central axis at the first contact point and the first inclined surface 121 form an angle less than 5 degrees. Under the condition that there is an interaction force between the sleeve 55 and the pawl 12, the sleeve 55 or the pawl 12 will deform to a certain extent, so that the sleeve 55 and the pawl 12 have a surface contact. If the tangent line of the helical line around the central axis at the first contact point and the first inclined surface 121 are nearly parallel, the contact area of the sleeve 55 and the pawl 12 when they deform will be larger, so that the local force of the pawl 12 can be reduced, the abrasion of the pawl 12 is reduced, and the stability of the mid-mounted transmission is improved.

[0274] In a preferred embodiment, the elastic member 14 is located at the first end of the pawl 12, that is, the elastic member 14 and the first inclined surface 121 are located at the same end of the pawl 12. The elastic member 14 exerts a force on the pawl 12 towards the sleeve 55, when the first end of the pawl 12 is above the first shift groove 551, the elastic member 14 presses the first end of the pawl 12, so that the first end of the pawl 12 enters the first shift groove 551, and the second end of the pawl 12 is lifted to be engaged on the first gear 32. Designing the elastic member 14 to press downward on the pawl 12 can save the occupied space of the shift mechanism 5, and thus the volume of the mid-mounted transmission can be reduced.

[0275] In a preferred embodiment, the elastic member 14 is located at the second end of the pawl 12, i.e. the elastic member 14 and the first inclined surface 121 are located at the two ends of the pawl 12 respectively. The elastic member 14 applies a force to the pawl 12 away from the sleeve 55. When the first end of the pawl 12 is located above the first shift groove 551, the elastic member 14 and the first shift groove 551 cooperate to make the elastic member 14 lift the second end of the pawl 12, while the first end of the pawl 12 enters the first shift groove 551, thereby achieving the locking of the first gear 32.

[0276] In a preferred embodiment, the pawl 12 rotates around a first axis, and the angle between the line connecting any point on the first axis and any point on the first inclined surface 121 and the first inclined surface 121 is less than 60 degrees. For example, the angle A between the line connecting any point on the first axis and any point on the first inclined surface 121 and the first inclined surface 121 is less than 60 degrees. In the case where the first inclined surface 121 and the edge of the first shift groove 551 are in contact, the length of the force arm of any point on the first inclined surface 121 subjected to the first shift groove 551 is the vertical distance between the point and the first axis. Therefore, the smaller the angle A is, the longer the corresponding force arm is, and the greater the torque of the sleeve 55 acting on the pawl 12 is.

[0277] Therefore, when the central transmission performs load shifting, the force between the sleeve 55 and the pawl 12 is smaller under the same shifting requirement, thereby further reducing the wear degree of the sleeve 55 and the pawl 12 during shifting.

[0278] In a further preferred embodiment, the shift mechanism 5 further comprises a second fixed member 18 located outside the sleeve 55, the second fixed member 18 penetrates the pawl 12, and the pawl 12 is sleeved on the second fixed member 18, and the first axis passes through the second fixed member 18. For example, the first axis is the central axis of the second fixed member 18, and the pawl 12 rotates around the second fixed member 18, thereby improving the stability of the pawl 12 during rotation.

[0279] In a preferred embodiment, the shift mechanism 5 further comprises a third fixed member 19 located outside the sleeve 55, and the elastic member 14 is installed on the third fixed member 19, thereby improving the stability of the elastic member 14 and further improving the reliability of the shifting process.

[0280] Specifically, the second fixed member 18 and the third fixed member 19 are both preferably circular rods.

[0281] In a preferred embodiment, the pawl 12 further comprises a second inclined surface 122, which is configured to abut against and slide along the edge of the first shift groove 551 when the pawl 12 moves out of the first shift groove 551. The angle between the tangent of the helical line of the helical surface around the central axis at the second contact point and the second inclined surface 122 is less than 10 degrees. Preferably, the angle between the tangent of the helical line of the helical surface around the central axis at the second contact point and the second inclined surface 122 is less than 5 degrees. Specifically, the first inclined surface 121 and the second inclined surface 122 are located at the same end of the pawl 12. During the relative rotation between the sleeve 55 and the pawl 12, the first inclined surface 121 abuts against one side edge of the first shift groove 551 and slides into the first shift groove 551, so that the first end of the pawl 12 enters the first shift groove 551 and the gear is engaged. During the continuous relative rotation between the sleeve 55 and the pawl 12, the second inclined surface 122 abuts against the other side edge of the first shift groove 551 and slides away from the first shift groove 551, so that the first end of the pawl 12 moves out of the first shift groove 551 and the gear is disengaged. Therefore, during the gear engagement and disengagement, the pawl 12 and the sleeve 55 can have a large contact area, so that the local stress of the pawl 12 and the sleeve 55 is reduced, and the wear of the pawl 12 and the sleeve 55 is reduced.

[0282] In a preferred embodiment, the sleeve 55 is provided with two first shift grooves 551 in the same helical form, and each first shift groove 551 corresponds to a group of pawls 12. Each first gear 32 corresponds to two pawls 12. When the gear is engaged, the first ends of the two pawls 12 simultaneously enter the first shift groove 551, and the second ends of the two pawls 12 simultaneously engage the first gear 32, so that the first gear 32 is locked from both ends, and the stability of the transmission after the gear engagement is improved.

[0283] In a preferred embodiment, a driving device is connected to the sleeve 55 and configured to drive the sleeve 55 to rotate. The relative positions of the first shift groove 551 and the pawl 12 are changed by rotating the sleeve 55, so that the gear shifting is performed, and the volume of the transmission is reduced.

[0284] In a preferred embodiment, the driving device comprises a sliding member 13, which is arranged in the first shift groove 551 and configured to move along the axial direction of the sleeve 55 to drive the sleeve 55 to rotate. The axial movement of the sliding member 13 is converted into the rotation of the sleeve 55, so that the movement space of the gear shifting mechanism 5 during the gear shifting is further reduced, and the volume of the transmission is further reduced. For example, a driving device for driving the sliding member 13 to move along the axial direction can be arranged in the sleeve 55 to drive the sleeve 55 to rotate. For details, please refer to FIGS. 7 and 8.

[0285] Embodiment 6

[0286] Referring to Figs. 38 to 43, the intermediate transmission comprises an intermediate shaft 2, a transmission mechanism and a first sensor 60, the transmission mechanism comprises an input mechanism 30, a transmission mechanism 40 and an output mechanism 70, the intermediate shaft 2 is used to install the crank 200 at both ends, so as to rotate under the drive of the crank 200, the transmission mechanism 40 is used to change the transmission path between the intermediate shaft 2 and the output mechanism 70, so that the intermediate shaft 2 drives the output mechanism 70 to rotate through different transmission paths; the first sensor 60 comprises a fourth fixed part 61 and a rotating part 62, the rotating part 62 is installed on the intermediate shaft 2, and the rotating part 62 is rotatable relative to the fixed part 61, and the positional relationship between the fourth fixed part 61 and the rotating part 62 is used to determine the rotating speed or position of the crank 200.

[0287] Specifically, the user pedals the pedal to drive the crank 200 to rotate, the crank 200 drives the intermediate shaft 2 to rotate, the intermediate shaft 2 drives the output mechanism 70 to rotate through the transmission mechanism 40, and the output mechanism 70 is used to connect the gear 92 and other mechanisms for providing power to the vehicle, so as to drive the vehicle to move forward. The crank 200 and the rotating part 62 are installed on the intermediate shaft 2, so according to the positional relationship between the fourth fixed part 61 and the rotating part 62, the rotating angle of the intermediate shaft 2 relative to the fourth fixed part 61 and the rotating speed of the intermediate shaft 2 can be determined, and then the rotating angle of the crank 200 relative to the fourth fixed part 61 and the rotating speed of the crank 200 can be determined. Since the fourth fixed part 61 is fixed on the vehicle, the rotating angle of the crank 200 relative to the vehicle can be determined according to the rotating angle of the crank 200 relative to the fourth fixed part 61, and then the position of the crank 200, that is, the position of the pedal, can be determined, and the pedaling frequency can be determined according to the rotating speed of the crank 200. The intermediate transmission is controlled to shift gears according to the position of the pedal or the pedaling frequency, and the appropriate shifting timing can be determined. For example, in the case of needing to shift gears, it is determined to shift gears when one of the pedals is at the highest position, or it is determined to shift gears when the pedaling speed is the lowest, so that the output torque of the motor is small at the time of shifting gears, the vibration of the vehicle at the time of shifting gears is reduced, and the riding experience of the user is improved.

[0288] In a preferred embodiment, the input mechanism 30 comprises a first input gear 34 fixedly installed on the intermediate shaft 2 and a second input gear 35 fixedly installed on the countershaft 3, the first input gear 34 and the second input gear 35 are engaged; the first input gear 34 is used to rotate under the drive of the intermediate shaft 2, so as to drive the countershaft 3 to rotate through the second input gear 35; the first input gear 34 is provided with a first mounting hole (not shown in the figure), and the rotating part 62 is installed in the first mounting hole. Since the first input gear 34 rotates synchronously with the intermediate shaft 2, the rotating part 62 is installed in the first mounting hole of the first input gear 34, so that the positional relationship between the intermediate shaft 2 and the housing 1 can be determined according to the positional relationship between the rotating part 62 and the fourth fixed part 61, and the installation space is saved.

[0289] The variable speed mechanism 40 further comprises a plurality of first transmission gears 41 fixed on the main shaft 2, a plurality of second transmission gears 42 fixed on the auxiliary shaft 3, and a shift mechanism 5 fixed on the auxiliary shaft 3, each first transmission gear 41 meshes with a corresponding second transmission gear 42; the shift mechanism 5 is used to rotate one of the second transmission gears 42 under the drive of the auxiliary shaft 3, so as to drive the output mechanism 70 to rotate through the corresponding first transmission gear 41. Specifically, the shift mechanism 5 locks one of the second transmission gears 42 with the auxiliary shaft 3, when the auxiliary shaft 3 rotates under the drive of the main shaft 2, the auxiliary shaft 3 drives the one of the second transmission gears 42 to rotate, and in turn drives the first transmission gear 41 meshing with the one of the second transmission gears 42 to rotate, and the first transmission gear 41 drives the output mechanism 70 to rotate. The number of teeth of different second transmission gears 42 is different, the number of teeth of different first transmission gears 41 is also different, different second transmission gears 42 correspond to different gears, by locking different second transmission gears 42 with the auxiliary shaft 3, the transmission route between the auxiliary shaft 3 and the output mechanism 70 can be changed, different output speeds are obtained, and variable speed is realized. It should be noted that the first input gear 34 and the first transmission gear 41 belong to different second gears 33, and the second input gear 35 and the second transmission gear 42 belong to different first gears 32.

[0290] In a preferred embodiment, the output mechanism 70 comprises an output sleeve 71 sleeved on the main shaft 2, the first transmission gear 41 is fixed on the output sleeve 71, and the output sleeve 71 is used to fix the gear disc 92, so as to save the installation space of the output mechanism 70 and reduce the size of the mid-mounted transmission.

[0291] In a preferred embodiment, the shift mechanism 5 comprises a pawl 51 and a driving mechanism 54, the driving mechanism 54 is used to drive the pawl 51 to rotate, so that the pawl 51 is engaged on one of the second transmission gears 42, so that one of the second transmission gears 42 is locked with the auxiliary shaft 3 and rotates under the drive of the auxiliary shaft 3. For example, the pawl 51 is fixed in the auxiliary shaft 3, the driving mechanism 54 drives the pawl 51 to rotate, so that one end of the pawl 51 is raised and engaged on one of the second transmission gears 42, so that the one of the second transmission gears 42 is locked with the auxiliary shaft 3. Specifically, the driving mechanism 54 can be the reset member 52 in the embodiments 3 or 4.

[0292] That is, in the embodiment, the transmission mechanism comprises a first input gear 34 fixed on the main shaft 2 and a second input gear 35 fixed on the auxiliary shaft 3, the first input gear 34 meshes with the second input gear 35; the first input gear 34 is used to rotate under the drive of the main shaft 2, and in turn drives the second input gear 35 to rotate and drives the auxiliary shaft 3 to rotate;

[0293] The transmission mechanism further comprises a plurality of first transmission gears 41 mounted on the middle shaft 2 and a plurality of second transmission gears 42 mounted on the secondary shaft 3, each first transmission gear 41 and a corresponding second transmission gear 42 are engaged;

[0294] The shift mechanism 5 is mounted on the secondary shaft 3, and the shift mechanism 5 is used to rotate one of the second transmission gears 42 under the drive of the secondary shaft 3, thereby driving the corresponding first transmission gear 41 to rotate and driving the front sprocket 92 to rotate.

[0295] In a preferred embodiment, the middle transmission further comprises a housing 1, and the fourth fixing member 61 is mounted in the housing 1, so that the first sensor 60 can be integrated in the middle transmission, saving installation space.

[0296] In a preferred embodiment, the fourth fixing member 61 is sleeved on the middle shaft 2, so that the installation space can be saved.

[0297] In a preferred embodiment, the first sensor 60 is a Hall sensor, the fourth fixing member 61 comprises a mounting shell 611 and at least one Hall element 612 mounted in the mounting shell 611, and the rotating member 62 comprises a magnet fixed to the first input gear 34. For example, the Hall elements 612 are uniformly arranged on a circuit board in the mounting shell 611, and the rotating member 62 comprises a magnet. According to the initial position and the current position of the magnet detected by any one of the Hall elements 612, the current position of the crank 200 can be determined, and according to the movement time of the magnet from the initial position to the current position, the rotation speed of the crank 200 can be determined.

[0298] In a preferred embodiment, a protrusion 613 is provided outside the mounting shell 611, the second mounting hole 24 is provided on the protrusion 613, and the protrusion 613 is fixedly installed in the housing 1 through the second mounting hole 24, so as to improve the connection stability and fixing strength between the mounting shell 611 and the housing 1.

[0299] In a preferred embodiment, the middle transmission is a parallel shaft transmission. Specifically, the middle transmission comprises a middle shaft 2, a secondary shaft 3, an input mechanism 30, a transmission mechanism 40, an output mechanism 70, a first sensor 60, and a housing 1; the middle shaft 2 and the secondary shaft 3 are arranged in parallel, and the two ends of the middle shaft 2 are used to install the crank 200, so as to be driven to rotate under the drive of the crank 200, and then drive the secondary shaft 3 to rotate through the input mechanism 30; the transmission mechanism 40 is used to change the transmission path between the secondary shaft 3 and the output mechanism 70, so that the secondary shaft 3 drives the output mechanism 70 to rotate through different transmission paths.

[0300] In another embodiment, the middle transmission can also have only one transmission shaft, i.e. the middle shaft 2 or the secondary shaft 3, and the rotating member in the first sensor 60 is mounted on the transmission shaft.

[0301] In a preferred embodiment, the number of the first transmission gears 41 is 7, and the number of the second transmission gears 42 is 7, so that seven-gear shifting can be realized.

[0302] In a preferred embodiment, the power shift transmission further comprises a second sensor 80 mounted on the countershaft 3 for detecting the torque of the input mechanism 30. For example, the second sensor 80 is a torque sensor, so that the torque of the input mechanism 30 can be detected, and then the appropriate shifting timing can be determined according to the torque of the input mechanism 30.

[0303] The preferred embodiments of the present patent application have been described above, but the present patent application is not limited to the above, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present patent application shall be included in the protection scope of the present patent application.

Claims

A mid-mounted transmission, characterized in that The application relates to a transmission mechanism for a motorcycle, comprising: a main shaft rotatably supported by a frame and to which torque is input; a secondary shaft parallel to the main shaft; a transmission mechanism connected to the main shaft and the secondary shaft and having at least two transmission ratios; a shift mechanism connected to the transmission mechanism and used for changing the transmission ratio of the transmission mechanism; a driving device connected to the shift mechanism; a front sprocket fixed to the transmission mechanism and outputting torque; the transmission mechanism comprises a plurality of first gears rotatably mounted on the secondary shaft and a plurality of second gears mounted on the main shaft, each first gear being engaged with a corresponding second gear; the shift mechanism is mounted in the secondary shaft to control locking and separation of the secondary shaft and any one or more first gears; when the first gear is locked with the secondary shaft, the first gear rotates under the drive of the secondary shaft and drives the main shaft through the second gear engaged with the first gear. The intermediate transmission according to claim 2, characterized in that the shift mechanism comprises a pawl, an elastic member, a sliding member, a screw, a nut and a first fixing member; the screw is used for rotating under the drive of the driving device, the nut is mounted on the screw, and the first fixing member is used for circumferentially limiting the nut; the sliding member is mounted in the secondary shaft and can axially slide along the secondary shaft, and the secondary shaft circumferentially limits the sliding member; the nut is used for driving the sliding member to axially move along the secondary shaft, and the sliding member can rotate in the circumferential direction of the nut; the pawl and the elastic member are mounted in the secondary shaft and located outside the sliding member; the sliding member is provided with a second shift groove, and the axial width of the second shift groove is not greater than the sum of the widths of any two adjacent pawls; when the sliding member slides to the position where the pawl is above the second shift groove, the elastic member is used for pressing the first end of the pawl into the second shift groove, the second end of the pawl is lifted, the secondary shaft and the first gear are locked; when the sliding member slides to the position where the pawl is away from the second shift groove, the first end of the pawl is lifted, the second end of the pawl is reset, and the secondary shaft and the first gear are separated. The intermediate transmission according to claim 2, characterized in that the shift mechanism further comprises a bearing mounted between the sliding member and the nut. The intermediate transmission according to claim 3, characterized in that the number of bearings is two, and the shift mechanism further comprises an axial positioning member arranged between the two bearings. The intermediate transmission according to claim 2, characterized in that at least one end of the screw extends to the outside of the secondary shaft and is used for being connected with the driving device; and / or, the edges of the two ends of the second shift groove are provided with inclined surfaces in the axial direction of the screw. The intermediate transmission according to claim 2, characterized in that the sliding member comprises a sliding member body and a boss protruding from the sliding member body, the boss is mounted in the secondary shaft and can axially slide along the secondary shaft. The intermediate transmission according to claim 2, characterized in that the shift mechanism further comprises a snap spring arranged at the two ends of the nut, and the snap spring is used for limiting the axial movement of the sliding member on the nut. The intermediate transmission according to claim 2, characterized in that the first fixing member comprises a plurality of fixing rods, and the two ends of the fixing rods are mounted on a shell where the shift mechanism is arranged. The intermediate transmission according to claim 8, characterized in that the plurality of fixing rods are arranged on the nut. The intermediate transmission according to claim 2, characterized in that Each of the first gear corresponds to two pawls, the two pawls are respectively arranged on both sides of the slider, the number of the second shift groove on the slider is two; And / or, the shift mechanism further comprises a second fixed part, the second fixed part is arranged outside the slider, the pawl is rotatably connected with the second fixed part; And / or, the auxiliary shaft is provided with a limiting hole, the limiting hole is consistent with the axial position of the first gear on the auxiliary shaft, and the pawl corresponding to the first gear and the elastic member are arranged in the limiting hole. The powershift transmission according to claim 1, characterized in that The shift mechanism comprises a sleeve, a pawl and an elastic member; the sleeve is located in the auxiliary shaft, the pawl and the elastic member are installed in the auxiliary shaft and located outside the sleeve; the sleeve is provided with a first shift groove, and the sleeve is used to rotate under the drive of external force; the elastic member abuts against the first end of the pawl to enter the first shift groove when the sleeve rotates to the first end of the pawl above the first shift groove, and makes the second end of the pawl lift to lock the auxiliary shaft and the first gear, and the sleeve is tangent to the pawl when the first end of the pawl is away from the first shift groove to lift the first end of the pawl, so that the second end of the pawl resets to separate the auxiliary shaft and the first gear. The intermediate transmission of claim 11, characterized in that: The first shift groove is a bevel groove, and the center line of the first shift groove is not parallel to the central axis of the sleeve. The intermediate transmission of claim 12, characterized in that: The shift mechanism further comprises a slider, the slider is arranged in the bevel groove and installed in the auxiliary shaft, the auxiliary shaft limits the slider in the circumferential direction, and the slider can slide along the axial direction of the auxiliary shaft, when not shifting, the slider and the sleeve rotate synchronously with the auxiliary shaft, when shifting is needed, the slider drives the sleeve to rotate relative to the auxiliary shaft by axial movement. The intermediate transmission of claim 13, characterized in that: The shift mechanism further comprises a screw rod, a nut and a first fixed part arranged in the sleeve, the nut is installed on the screw rod, the first fixed part limits the nut in the circumferential direction, and the screw rod drives the nut to move axially along the screw rod by rotating to drive the slider to move axially along the screw rod. The intermediate transmission of claim 14, characterized in that: At least one end of the screw rod extends to the outside of the auxiliary shaft for connecting with the driving device. The intermediate transmission of claim 14, characterized in that: The first fixed part comprises a plurality of fixed rods, both ends of the fixed rod are installed on the shell where the shift mechanism is located. The intermediate transmission of claim 16, characterized in that: The plurality of fixed rods are arranged in the nut. The intermediate transmission of claim 11, characterized in that: Each of the first gear corresponds to two pawls, the two pawls are respectively arranged on both sides of the sleeve, the number of the first shift groove on the sleeve is two. The intermediate transmission of claim 11, characterized in that: The shift mechanism further comprises a planetary gear assembly for driving the sleeve to rotate, the output end of the planetary gear assembly is connected with the sleeve or the screw rod. The powershift transmission according to claim 1, characterized in that The auxiliary shaft is hollow. The intermediate transmission of claim 20, characterized in that: The transmission mechanism is gear transmission; The shift mechanism comprises a reset member, a rotary control member and at least two pawls, a recess is formed on the secondary shaft, the pawls are rotatably installed in the recess, one end of the reset member abuts against the secondary shaft, the other end of the reset member abuts against one end of the pawl, and the outer periphery of the rotary control member is provided with a control groove formed along the circumferential direction thereof; The pawl has a locking portion, a control portion and an extension portion, the control portion is located on the side opposite to the locking portion, the control portion is connected with the locking portion through the extension portion, the locking portion of the pawl is located on the outer side of the rotary control member, and the control portion of the pawl is located on the inner side of the rotary control member; When the rotary control member and the secondary shaft are deflected in terms of the rotation angle, the control portion of the pawl is popped up and enters the control groove, so that the gear of the transmission mechanism is fixed with the secondary shaft to change the transmission ratio. The intermediate transmission of claim 21, characterized in that: The control portion is protruded from the extension portion in a triangular cross section. The intermediate transmission of claim 21, characterized in that: A round corner is arranged at the position where the control portion contacts the inner periphery of the rotary control member. The intermediate transmission of claim 21, characterized in that: The locking portion and the control portion are located in the same radial plane. The intermediate transmission of claim 21, characterized in that: The outer periphery of the rotary control member is provided with an avoiding groove formed along the circumferential direction thereof, and the extension portion of the pawl passes through the avoiding groove to be connected with the control portion and the locking portion respectively. The power-split transmission of claim 20, characterized in that: The driving device is hidden in the inner side of the secondary shaft. The intermediate transmission of claim 26, characterized in that: The transmission mechanism is a gear transmission. The shift mechanism comprises at least two pawls, a reset member and a rotary control member, a recess is formed on the secondary shaft, the pawls are rotatably installed in the recess, one end of the reset member abuts against the secondary shaft, the other end of the reset member abuts against one end of the pawl, the outer periphery of the rotary control member is provided with a control groove, and the pawl is arranged on the outer side of the rotary control member; When the rotary control member and the secondary shaft are deflected in terms of the rotation angle, one end of the pawl enters the control groove, so that the gear of the transmission mechanism is fixed with the secondary shaft to change the transmission ratio. The intermediate transmission of claim 27, characterized in that: The control groove is a spiral groove. The intermediate transmission of claim 28, characterized in that: The control groove comprises at least two through grooves, the at least two through grooves are arranged in a spiral shape, the through grooves are formed along the circumferential direction of the rotary control member, and adjacent two through grooves are not communicated. The powershift transmission according to claim 27 or 28, characterized in that The rotary control member is arranged on the inner side of the secondary shaft, and the driving device is arranged on the inner side of the rotary control member. The powershift transmission according to any one of claims 21 to 27, characterized in that A rotating speed mixing mechanism is further arranged, which is connected with the shift mechanism, the secondary shaft and the driving device respectively; When the driving device does not perform the shift operation, the rotating speed mixing mechanism synchronously rotates the shift mechanism and the secondary shaft; when the driving device performs the shift operation, the rotating speed mixing mechanism causes the rotary control member of the shift mechanism and the secondary shaft to be deflected in terms of the rotation angle. The intermediate transmission of claim 31, characterized in that: The rotating speed mixing mechanism comprises a first ring gear, a first sun gear, a planet carrier, a plurality of planetary gears, a second ring gear and a second sun gear, the plurality of planetary gears are rotatably connected to the planet carrier, the plurality of planetary gears are respectively engaged with the first ring gear, the first sun gear, the second ring gear and the second sun gear, the first ring gear is connected with the rotating control member of the gear shifting mechanism, the second ring gear is connected with the lay shaft, the first sun gear is connected with the driving device; The middle transmission further comprises a housing, the housing is fixedly connected with the frame, the lay shaft is rotatably supported in the housing, the front sprocket is located outside the housing, the transmission mechanism and the gear shifting mechanism are arranged inside the housing, the middle shaft penetrates through the housing and extends out of the housing at two ends and is rotatably supported on the frame, the two ends of the middle shaft are fixedly connected with the input assembly respectively, the input assembly comprises a left crank and a right crank; The second sun gear is further fixedly connected with the housing. The intermediate transmission of claim 32, characterized in that: The plurality of planetary gears are double planetary gears, the double planetary gears comprise first planetary gears and second planetary gears with the same number of teeth, the first planetary gears are respectively engaged with the first ring gear and the first sun gear, and the second planetary gears are respectively engaged with the second ring gear and the second sun gear. The intermediate transmission of claim 32, characterized in that: The plurality of planetary gears are four planetary gears, the four planetary gears comprise third planetary gears and sixth planetary gears with the same number of teeth, and fourth planetary gears and fifth planetary gears with the same number of teeth, the number of teeth of the third planetary gears is less than that of the fourth planetary gears, the third planetary gears are engaged with the first ring gear, the fourth planetary gears are engaged with the first sun gear, the sixth planetary gears are engaged with the second ring gear, and the fifth planetary gears are engaged with the second sun gear. The intermediate transmission of claim 26, characterized in that: The gear position feedback device comprises a plurality of row arranged Hall elements and magnets, the driving device is connected with a driving device speed reduction mechanism, the driving device speed reduction mechanism comprises a speed reduction sun gear, a speed reduction planetary gear, a speed reduction planet carrier and a speed reduction ring gear, the speed reduction planetary gear is rotatably mounted on the speed reduction planet carrier, the speed reduction planetary gear is respectively engaged with the speed reduction sun gear and the speed reduction ring gear, the speed reduction sun gear is fixedly connected with the driving device, the magnets are arranged on the speed reduction ring gear, the speed reduction planet carrier is connected with the housing, and the Hall elements are used for sensing the magnetic field intensity of the magnets to obtain pulse signals for judging the gear position to which the gear shifting mechanism rotates. The intermediate transmission of claim 35, characterized in that: The maximum angle of the plurality of row arranged Hall elements does not exceed 360 degrees. The intermediate transmission of claim 26, characterized in that: The driving device is a gear shifting motor, and the gear shifting motor is fixed to the housing. The powershift transmission according to any one of claims 21 to 26, characterized in that The transmission mechanism comprises a first gear set and a second gear set, torque is input from the middle shaft, sequentially passes through the first gear set and the second gear set and is then output to the front sprocket. The intermediate transmission of claim 38, characterized in that: The first gear set comprises a first driving gear and a first driven gear which are engaged with each other, the first driving gear is fixedly connected with the middle shaft, and the first driven gear is fixedly connected with the lay shaft. The second gear set comprises a second driving gear and a second driven gear which are engaged with each other, the second driving gear is fixedly connected with the lay shaft, and the second driven gear is fixedly connected with the front sprocket. The second gear set comprises a second driving gear and a second driven gear which are in mesh with each other, the second driving gear is movably connected to the layshaft, the second driving gear is relatively fixed or relatively movable to the layshaft by the gear shifting mechanism to shift gears, the second driven gear is fixedly connected with a transmission sleeve, and the transmission sleeve is movably connected with the intermediate shaft. The intermediate transmission of claim 39, characterized in that: The second driving gear and the second driven gear are provided in plurality, one of the second driving gears with the least number of teeth is fixed to the layshaft, and a one-way clutch is arranged between one of the second driven gears with the most number of teeth and the transmission sleeve. The powershift transmission according to claim 1, characterized in that The gear shifting mechanism comprises a sleeve, a pawl and an elastic member, the sleeve is provided with a first gear shifting groove, and the elastic member is used to drive the first end of the pawl to enter the first gear shifting groove and the second end of the pawl to be lifted up when the first end of the pawl is located above the first gear shifting groove, so as to lock the first gear located outside the sleeve. The pawl comprises a first inclined surface, the first inclined surface is used to abut against the edge of the first gear shifting groove and slide when the first end of the pawl enters the first gear shifting groove, the edge of the first gear shifting groove is in the shape of a helical surface around the central axis of the sleeve, the included angle between the helical line around the central axis in the helical surface and the first inclined surface at the first contact point is less than 10 degrees, and the first contact point is the contact point between the first inclined surface and the helical line. The intermediate transmission of claim 41, characterized in that: The elastic member is located at the first end of the pawl and is used to press the first end of the pawl to make the first end of the pawl enter the first gear shifting groove when the first end of the pawl is located above the first gear shifting groove; or The elastic member is located at the second end of the pawl and is used to lift up the second end of the pawl when the first end of the pawl is located above the first gear shifting groove; or The pawl further comprises a second inclined surface, the second inclined surface is used to abut against the edge of the first gear shifting groove and slide when the pawl leaves the first gear shifting groove, the included angle between the helical line around the central axis in the helical surface and the second inclined surface at the second contact point is less than 10 degrees, and the second contact point is the contact point between the second inclined surface and the helical line. The intermediate transmission of claim 41, characterized in that: The pawl rotates around a first axis, and the included angle between the line connecting a point on the first axis and the first inclined surface and the first inclined surface is less than 60 degrees. The intermediate transmission of claim 43, characterized in that: The gear shifting mechanism further comprises a second fixing member located outside the sleeve, the pawl is sleeved on the second fixing member, and the first axis is the central axis of the second fixing member. The intermediate transmission of claim 41, characterized in that: The pawl rotates around a first axis, and the included angle between the line connecting the intersection of the first axis and the median surface of the pawl and any point on the first inclined surface and the first inclined surface is less than 60 degrees. The intermediate transmission of claim 41, characterized in that: Two first gear shifting grooves in the same helical shape are arranged on the sleeve, and each first gear shifting groove corresponds to a group of pawls. The intermediate transmission of any of claims 41-46, characterized in that: The driving device is in transmission connection with the sleeve and is used to drive the sleeve to rotate. The intermediate transmission of claim 47, characterized in that: The driving device comprises a sliding member which is arranged in the first gear shifting groove and is used to move along the axial direction of the sleeve to drive the sleeve to rotate. The powershift transmission according to claim 1, characterized in that The transmission mechanism comprises a first input gear fixedly installed on the middle shaft and a second input gear fixedly installed on the auxiliary shaft, the first input gear and the second input gear being engaged; the first input gear is used to rotate under the driving of the middle shaft, thereby driving the second input gear to rotate and driving the auxiliary shaft to rotate; The transmission mechanism further comprises a plurality of first transmission gears installed on the middle shaft and a plurality of second transmission gears installed on the auxiliary shaft, each first transmission gear and the corresponding second transmission gear being engaged; The shift mechanism is installed on the auxiliary shaft, and is used to drive one of the second transmission gears to rotate under the driving of the auxiliary shaft, thereby driving the corresponding first transmission gear to rotate and driving the front sprocket to rotate. The intermediate transmission of claim 49, characterized in that: An output sleeve is sleeved on the middle shaft, and the first transmission gears and the front sprocket are installed on the output sleeve; Crankshafts are installed at both ends of the middle shaft, and torque is input into the middle shaft through the crankshafts. The intermediate transmission according to claim 49 or 50, characterized in that A first sensor is further included, the first sensor comprising a fourth fixing member and a rotating member, the rotating member being installed on the middle shaft, the fourth fixing member being arranged on the middle transmission or a vehicle on which the middle transmission is arranged, and the rotating member being rotatable relative to the fourth fixing member, the positional relationship between the fourth fixing member and the rotating member being used to determine the rotational speed or position of the front sprocket. The intermediate transmission of claim 51, characterized in that: A first installation hole is formed in the first input gear, and the rotating member is installed in the first installation hole; And / or, the fourth fixing member is sleeved on the middle shaft; And / or, the middle transmission further comprises a second sensor, the second sensor being installed on the auxiliary shaft and being used to detect the torque of the first input gear or the second input gear. The intermediate transmission of claim 51, characterized in that: The middle transmission further comprises a housing, and the fourth fixing member is installed in the housing. The intermediate transmission of claim 53, characterized in that: The fourth fixing member comprises an installation shell and at least one Hall element installed in the installation shell, and the rotating member comprises a magnet, the magnet being fixed to the first input gear. The intermediate transmission of claim 54, characterized in that: A protrusion is arranged on the outside of the installation shell, and the protrusion is fixedly installed in the housing. A mid-motor comprising a mid-transmission according to any one of claims 1 to 55, characterized in that A power-assisted motor and a power-assisted motor deceleration mechanism are further included, the power-assisted motor being connected with the transmission mechanism through the power-assisted motor deceleration mechanism. A vehicle characterized by comprising: A vehicle body and a middle motor as claimed in claim 56 are included, and the middle motor is installed on the vehicle body.

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