Middle shaft transmission and middle motor

Abstract

The utility model belongs to the technical field of transmissions, and particularly relates to a middle shaft transmission and a middle motor. The center shaft transmission provided by the utility model comprises a center shaft which is rotatably supported on a vehicle frame, and torque is input from the center shaft; the auxiliary shaft is hollow and is parallel to the middle shaft; the transmission mechanism is connected with the middle shaft and the auxiliary shaft and has at least two transmission ratios; the driving device is connected with the gear shifting mechanism and is hidden in the inner side of the auxiliary shaft; the gear shifting mechanism is linked with the transmission mechanism and is used for changing the transmission ratio of the transmission mechanism; and the front chain wheel is fixed on the transmission mechanism and outputs torque. According to the center shaft transmission and the middle motor, the driving device is hidden in the inner side of the auxiliary shaft, the space in the auxiliary shaft is reasonably utilized, the whole center shaft transmission becomes more compact, and the size of the whole center shaft transmission is reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of transmission, particularly relates to a middle axle transmission and middle motor. BACKGROUND

[0002] Ebike is the abbreviation of Electric Bike, also known as electric assist bicycle, 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.

[0003] Electric motor is usually installed in the middle of the wheel or frame, and the required electric energy can be supplied 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 DC brushless motor, which can be divided into 250W, 350W, 500W, etc. according to different power levels.

[0004] Chinese patent document CN117341882A discloses a bicycle middle box type assist variable speed motor, the variable speed driving device thereof includes gear sheet, L-shaped pull rod, pull rod shaft, reset spring, pull rod distribution gear, driving roller, cam cover, bearing, micro gear motor and position sensor, wherein the micro gear motor is arranged on the outer side of the secondary shaft, which causes the device to be too large in size to some extent.

[0005] Therefore, the prior art needs to be improved and developed. INVENTION CONTENTS

[0006] The purpose of the present application is to provide a middle axle transmission and middle motor, so that the entire middle axle transmission becomes more compact, and the volume of the entire middle axle transmission is reduced.

[0007] The middle axle transmission provided by the present application comprises:

[0008] The middle axle is rotatably supported on the frame, and torque is input from the middle axle;

[0009] The secondary shaft is hollow and parallel to the middle axle;

[0010] The transmission mechanism is connected with the middle axle and the secondary shaft respectively, and has at least two transmission ratios;

[0011] The driving device is connected with the gear shifting mechanism and is hidden inside the secondary shaft;

[0012] The gear shifting mechanism is linked with the transmission mechanism and is used for changing the transmission ratio of the transmission mechanism;

[0013] The front sprocket is fixed on the transmission mechanism and outputs torque.

[0014] Further, the shift mechanism comprises at least two pawls, a reset member and a rotation control member, the countershaft is provided with a groove, the pawls are rotatably installed in the groove, one end of the reset member abuts against the countershaft, the other end of the reset member abuts against the pawls, and the rotation control member is provided with a control groove on its outer circumferential surface, and the pawls are arranged outside the rotation control member.

[0015] When the rotation control member and the rotation angle of the countershaft are deflected, one end of the pawl falls into the control groove, so that the gear of the shift mechanism is fixed with the countershaft to change the transmission ratio.

[0016] Further, the rotation control member is arranged inside the countershaft, and the driving device is arranged inside the rotation control member.

[0017] Further, the control groove is a spiral groove.

[0018] Further, the control groove is at least two spiral grooves arranged in a spiral manner, and the grooves are arranged along the circumferential direction of the rotation control member, and adjacent two grooves are not communicated.

[0019] Further, a rotating speed mixing mechanism is further included, and the rotating speed mixing mechanism is connected to the shift mechanism, the countershaft and the driving device respectively.

[0020] When the driving device does not perform the shift operation, the rotating speed mixing mechanism synchronously rotates the shift mechanism and the countershaft; when the driving device performs the shift operation, the rotating speed mixing mechanism deflects the rotation angle of the rotation control member of the shift mechanism and the countershaft.

[0021] Further, the rotating speed mixing mechanism comprises a first ring gear, a first sun gear, a planet carrier, a multiple planetary gear, a second ring gear and a second sun gear, the multiple planetary gear is rotatably connected to the planet carrier, the multiple planetary gear is meshed with the first ring gear, the first sun gear, the second ring gear and the second sun gear respectively, the first ring gear is connected to the rotation control member of the shift mechanism, the second ring gear is connected to the countershaft, the first sun gear is connected to the driving device, and the second sun gear is fixedly connected to an outer shell.

[0022] Further, the multiple planetary gear is a double planetary gear, the double planetary gear comprises first and second planetary gears with the same number of teeth, the first planetary gear is meshed with the first ring gear and the first sun gear respectively, and the second planetary gear is meshed with the second ring gear and the second sun gear respectively.

[0023] Further, the multiple planetary gears are four planetary gears, the four planetary gears include 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 gear has a smaller number of teeth than the fourth planetary gear, the third planetary gear meshes with the first ring gear, the fourth planetary gear meshes with the first sun gear, the sixth planetary gear meshes with the second ring gear, and the fifth planetary gear meshes with the second sun gear.

[0024] Further, the gear feedback device includes a plurality of row-arranged Hall elements and magnets, the driving device is connected to a driving device deceleration mechanism, the driving device deceleration mechanism includes a deceleration sun gear, a deceleration planetary gear, a deceleration planet carrier, and a deceleration ring gear, the deceleration planetary gear is rotatably mounted on the deceleration planet carrier, the deceleration planetary gear meshes with the deceleration sun gear and the deceleration ring gear respectively, the deceleration sun gear is fixedly connected to the driving device, the magnets are arranged on the deceleration ring gear, the deceleration planet carrier is fixed to the housing, and the Hall elements inductively detect the magnetic field strength of the magnets on the deceleration ring gear to obtain pulse signals to determine the gear position to which the gear shifting mechanism rotates.

[0025] Further, the maximum angle of the plurality of row-arranged Hall elements is not more than 360 degrees.

[0026] Further, the driving device is a gear shifting motor, and the gear shifting motor is fixedly connected to the housing.

[0027] Further, the transmission mechanism includes 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.

[0028] Further, the first gear set includes a first driving gear and a first driven gear that mesh with each other, the first driving gear is fixed to the middle shaft, and the first driven gear is fixed to the auxiliary shaft.

[0029] The second gear set includes a second driving gear and a second driven gear that mesh with each other, the second driving gear is movably connected to the auxiliary shaft, the second driving gear is relatively fixed or relatively movable to the auxiliary shaft through the gear shifting mechanism to perform gear shifting, the second driven gear is fixedly connected with a transmission sleeve, and the transmission sleeve is movably connected with the middle shaft.

[0030] Further, a plurality of second driving gears and a plurality of second driven gears are provided, one of the second driving gears with the smallest number of teeth is fixed to the auxiliary shaft, and a one-way clutch is arranged between one of the second driven gears with the largest number of teeth and the transmission sleeve.

[0031] The application also provides a middle motor, comprising the above-mentioned middle axle transmission, further comprising a power-assisted motor and a power-assisted motor deceleration mechanism, the power-assisted motor is connected with the transmission mechanism through the power-assisted motor deceleration mechanism.

[0032] From the above, the middle axle transmission and the middle motor of the application conceal the driving device inside the secondary shaft, reasonably utilize the space inside the secondary shaft, make the whole middle axle transmission more compact, and reduce the volume of the whole middle axle transmission.

[0033] Other features and advantages of the application will be set forth in the following description, and in part will become apparent from the description, or can be learned by practice of the application. The objects and other advantages of the application will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is a perspective view of the middle axle transmission of the application.

[0035] Figure 2 It is a perspective view of the middle axle transmission of the application (the shell, the front sprocket and the crank are hidden).

[0036] Figure 3 It is a top view of Figure 2 .

[0037] Figure 4 It is a cross-sectional view of Figure 3 .

[0038] Figure 5 It is a schematic view of the assembly of the secondary shaft and the shifting mechanism.

[0039] Figure 6 It is a schematic view of the shifting process of the shifting mechanism.

[0040] Figure 7 It is a cross-sectional view of the shifting process of the shifting mechanism.

[0041] Figure 8 It is a perspective view of another embodiment of the rotation control member.

[0042] Figure 9 It is a perspective view of the rotation speed mixing mechanism.

[0043] Figure 10 It is an exploded view of the rotation speed mixing mechanism.

[0044] Figure 11 It is a schematic view of the rotation speed mixing mechanism.

[0045] Figure 12 It is a schematic view of another embodiment of the rotation speed mixing mechanism.

[0046] Figure 13 The schematic diagram of the speed mixing mechanism and the gear feedback device.

[0047] Figure 14 The structural schematic diagram of the gear feedback device

[0048] Figure 15 The structural schematic diagram of the motor in the application.

[0049] Explanation of reference numerals:

[0050] 1 - housing,

[0051] 2 - middle shaft,

[0052] 3 - secondary shaft, 31 - groove,

[0053] 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,

[0054] 5 - gear shifting mechanism, 51 - pawl, 52 - reset member, 53 - rotary control member, 531 - control groove, 5311 - spiral groove, 5312 - through groove,

[0055] 6 - driving device,

[0056] 7 - speed mixing mechanism, 71 - first ring gear, 72 - first sun gear, 73 - planet carrier, 74 - multiple planetary gear, 741 - double planetary gear, 7411 - first planetary gear, 7412 - second planetary gear, 742 - four planetary gear, 7421 - third planetary gear, 7422 - fourth planetary gear, 7423 - fifth planetary gear, 7424 - sixth planetary gear, 75 - second sun gear, 76 - second ring gear,

[0057] 8 - input assembly, 81 - left crank, 82 - right crank,

[0058] 9 - output assembly, 91 - transmission sleeve, 92 - front sprocket, 93 - one-way clutch,

[0059] 10 - assist motor,

[0060] 11 - assist motor speed reduction mechanism,

[0061] 12 - driving device speed reduction mechanism, 121 - speed reduction sun gear, 122 - speed reduction planetary gear, 123 - speed reduction planet carrier, 124 - speed reduction ring gear,

[0062] 13 - gear feedback device, 131 - hall element, 132 - circuit board, 133 - magnet. DETAILED DESCRIPTION

[0063] The embodiments of the present application will be described in detail below with reference to the drawings, examples of which are shown in the accompanying drawings, wherein the same or similar components are denoted by the same or similar reference numerals throughout. The embodiments described below by reference to the drawings are exemplary only, and are used only for explaining the present application, and should not be understood as limiting the present application.

[0064] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features limited by "first" and "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0065] In the description of the present application, it should be noted that, unless otherwise specifically defined and limited, the terms "mounting", "connecting", "connection" should be broadly understood, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0066] In the utility model, unless otherwise expressly provided and limited, the first feature is "on" or "under" the second feature, which can include that the first and second features are in direct contact, or the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature "on", "above" and "on the surface of" the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "under", "below" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0067] The intermediate shaft transmission in the application is fixedly installed at the bottom of the middle of the frame of the vehicle, and comprises a shell 1, an intermediate shaft 2, a countershaft 3, a transmission mechanism 4, a driving device 6, a gear shifting mechanism 5 and a front sprocket 92, wherein the shell 1 is fixed on the frame, the countershaft 3 is rotatably supported in the shell 1, all the parts are hidden inside the shell 1 except that the front sprocket 92 is exposed, the two ends of the intermediate shaft 2 extend out of the shell 1 and are rotatably supported on the frame, the two ends of the intermediate shaft 2 are fixedly connected with input assemblies 8 respectively, the input assemblies 8 comprise left and right cranks 81 and 82, the cranks are rotatably connected with pedals, and the torque generated by a rider through pedaling is transmitted to the intermediate shaft 2, and then input to the transmission mechanism 4, the gear shifting mechanism 5 is linked with the transmission mechanism 4, the transmission mechanism 4 is used for changing the transmission ratio and output speed, the meshing relationship of different gears is changed to realize the switching of different gears, the front sprocket 92 is fixed on the transmission mechanism 4 and is used for outputting torque, and the front sprocket 92 further inputs the torque to a freewheel through chain transmission or belt transmission to drive the rear wheel of the vehicle to rotate.

[0068] The device can be used in bicycles, folding bicycles, Ebikes, electric assist bicycles, electric vehicles, electric motorcycles, cargo freight electric vehicles, tricycles, scooters, electric scooters and the like.

[0069] Figure 1 It is a perspective view of the intermediate shaft transmission in the application. Figure 2 It is a perspective view of the intermediate shaft transmission in the application (the shell 1, the front sprocket 92 and the crank are hidden). Figure 3 It is a top view of the intermediate shaft transmission in the application. Figure 2 It is a top view of the intermediate shaft transmission in the application. Figure 4 It is a top view of the intermediate shaft transmission in the application. Figure 3A cross-sectional view of the transmission. The transmission mechanism 4 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 in mesh with each other. The first driving gear 411 is fixed to the main shaft 2, and the first driven gear 412 is fixed to the countershaft 3. The first driving gear 411 is driven to rotate by the main shaft 2, and in turn drives the first driven gear 412 to rotate the countershaft 3. In this embodiment, the number of teeth of the first driving gear 411 is greater than that of the first driven gear 412, so the transmission ratio of the first gear set 41 is less than 1, i.e. the first gear set 41 is a speed-increasing transmission.

[0070] The rotation of the countershaft 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 in mesh with each other. The second driving gear 421 is movably connected to the countershaft 3, and the second driven gear 422 is fixedly connected to a transmission sleeve 91 which is movably connected to the main shaft 2. The second driving gear 421 is relatively fixed or relatively movable with respect to the countershaft 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.

[0071] In this embodiment, the second gear set 42 is provided with seven second driving gears 421 and seven second driven gears 422. As can be seen in Figure 4 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 main shaft transmission has seven gear positions.

[0072] To achieve gear shifting, the shift mechanism 5 is provided, which can fix one of the six second driving gears 421 with the countershaft 3. Figure 5 A schematic view of the countershaft 3 and the shift mechanism 5. Figure 6 A schematic view of the gear shifting process of the shift mechanism 5. The shift mechanism 5 comprises at least two pawls 51, a reset member 52 and a rotating control member 53. The countershaft 3 is provided with a groove 31 along its circumferential direction, and a rotating shaft is installed in the groove 31. The at least two pawls 51 are arranged in a row along the axial direction of the countershaft 3 and are rotatably installed in the groove 31 behind the rotating shaft. The rotating control member 53 has an outer diameter smaller than that of the countershaft 3, and is hollow. The outer circumferential surface of the rotating control member 53 is provided with a control groove 531, and the pawls 51 are arranged outside the rotating control member 53. One end of the reset member 52 abuts against the countershaft 3, and the other end of the reset member 52 abuts against the pawls 51. The reset member 52 presses the one end of the pawls 51 down to keep abutting against the outer circumferential surface of the rotating control member 53. It should be noted that the rotating control member 53 is not stationary, but rotates synchronously with the countershaft 3.

[0073] When the rotating angle of the rotating control member 53 and the countershaft 3 deviates, asFigure 7 As shown, one end of the pawl 51 falls into the control groove 531, and the other end of the pawl 51 pops up and is clamped into the locking groove 4211 of the second driving gear 421, so that the second driving gear 421 of the gear shift mechanism 5 is fixed with the lay shaft 3 to change the transmission ratio.

[0074] In the embodiment, as shown, Figure 6 The control groove 531 provided on the outer circumferential surface of the rotation control member 53 is a spiral groove 5311, which is convenient to machine and can be formed by numerical control lathe milling or electric spark machining.

[0075] In another embodiment, as shown, Figure 8 The control groove 531 provided on the outer circumferential surface of the rotation control member 53 is at least two through grooves 5312 arranged in a spiral shape, the cross section of the through groove 5312 is a rectangle, the length and width of the cross section are respectively matched with the length and width of the pawl 51, the through groove 5312 is opened along the circumferential direction of the rotation control member 53, and the 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 one 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 gear jumping and ensuring the accuracy of gear shifting.

[0076] In the 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 a one-way clutch 93 is arranged between one of the second driving gears 422 with the largest number of teeth and 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 that 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 lay 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.

[0077] The one-way clutch 93 can adopt a roller clutch, a wedge block clutch, a pawl 51 clutch, a friction clutch, an electromagnetic clutch, etc.

[0078] Since the auxiliary shaft 3 and the rotation control member 53 are hollow, in order to reasonably utilize the space in the auxiliary shaft 3, make the whole axle transmission more compact, and reduce the volume of the whole axle transmission, the driving device 6 is hidden inside the auxiliary shaft 3, and the driving device 6 has a positional relationship with the auxiliary shaft 3 and the shift mechanism 5, the rotation control member 53 is arranged inside the auxiliary shaft 3, and the driving device 6 is arranged inside the rotation control member 53.

[0079] 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 auxiliary shaft 3 and always keep the same rotating speed as the rotation control member 53, which will cause a great power loss.

[0080] In order to facilitate the control of the rotation control member 53 of the shift mechanism 5, a rotating speed mixing mechanism 7 is arranged. Figure 9 It is a perspective view of the rotating speed mixing mechanism 7, Figure 10 It is an exploded view of the rotating speed mixing mechanism 7, Figure 11 It is a schematic view of the rotating speed mixing mechanism 7. The rotating speed mixing mechanism 7 is connected to the shift mechanism 5, the auxiliary shaft 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 rotation to the rotating speed mixing mechanism 7, the rotating speed mixing mechanism 7 synchronizes the rotation of the rotation control member 53 of the shift mechanism 5 and the auxiliary shaft 3; when the driving device 6 performs the shift operation, the rotating speed mixing mechanism 7 causes the rotation angle of the rotation control member 53 of the shift mechanism 5 and the auxiliary shaft 3 to be deflected.

[0081] The rotating speed mixing mechanism 7 comprises a first ring gear 71, a first sun gear 72, a planet carrier 73, a multi-connected planet gear 74, a second ring gear 76 and a second sun gear 75, the multi-connected planet gear 74 is rotatably connected to the planet carrier 73, the multi-connected planet gear 74 is meshed 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 to the rotation control member 53 of the shift mechanism 5, the second ring gear 76 is connected to the auxiliary shaft 3, the first sun gear 72 is connected to the driving device 6, and the second sun gear 75 is connected to the housing 1.

[0082] The first ring gear 71 and the rotation control member 53 can be split type or integral type, the split type is more convenient to process, and the integral type has higher part structure strength, as shown in Figure 8 The first ring gear 71 and the rotation control member 53 are integrally formed.

[0083] The multi-connected planet gear 74 can be a double-connected planet gear, a triple-connected planet gear or more, the more planet gears, the greater the transmission ratio of the rotating speed mixing mechanism 7 can be obtained. The greater the transmission ratio of the rotating speed mixing mechanism 7, the smaller the torque required by the driving device 6 under the same load.

[0084] In the embodiment, the multiple planetary gear 74 is a double planetary gear 741, as shown in the figure. Figure 11 The double planetary gear 741 includes first and second planetary gears 7411 and 7412 with the same number of teeth, the first planetary gear 7411 meshes with the first ring gear 71 and the first sun gear 72, and the second planetary gear 7412 meshes with the second ring gear 76 and the second sun gear 75. The double planetary gear 741 is simple in structure and convenient to assemble. Since the transmission ratio of the rotational speed mixing mechanism 7 is small, the driving device 6 needs to be selected in a large torque mode.

[0085] In another embodiment, the multiple planetary gear 74 is a four planetary gear 742, as shown in the figure. Figure 12 The four planetary gear 742 includes third and sixth planetary gears 7421 and 7424 with the same number of teeth, and fourth and fifth planetary gears 7422 and 7423 with the same number of teeth, the number of teeth of the third planetary gear 7421 is less than that of the fourth planetary gear 7422, the third planetary gear 7421 meshes with the first ring gear 71, the fourth planetary gear 7422 meshes with the first sun gear 72, the sixth planetary gear 7424 meshes with the second ring gear 76, and the fifth planetary gear 7423 meshes with the second sun gear 75. Compared with the double planetary gear 741, the four planetary gear 742 can make the rotational speed mixing mechanism 7 obtain a larger transmission ratio, so that the driving device 6 can be selected in a small torque mode. The driving device 6 in a small torque mode is smaller in size, which can further reduce the space of the central shaft transmission. Alternatively, the driving device 6 is selected in a large torque mode, which has a longer service life.

[0086] When no shifting operation is performed, i.e., the driving device 6 does not rotate, the first sun gear 72 is equivalent to being fixed due to the resistance of the output shaft itself. Since the first and second planetary gears 7411 and 7412 of the double planetary gear 741 have the same number of teeth, or the third and sixth planetary gears 7421 and 7424 of the four planetary gear 742 have the same number of teeth, the rotating control member 53 will be driven by the countershaft 3 and rotate at the same rotational speed and in the same rotational direction.

[0087] When the shifting operation is needed, the driving device 6 rotates in a forward or reverse direction for a certain number of revolutions, and the rotational speed of the countershaft 3 and the rotational speed of the first sun gear 72 are mixed and output to the rotating 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 rotating 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 rotating 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 rotating control member 53 rotates synchronously with the countershaft 3.

[0088] The driving device 6 is a gear shifting 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 accuracy requirements for position, speed and angle. The gear shifting motor is fixedly connected to the shell 1, and the gear shifting motor does not need to rotate with the secondary shaft 3, avoiding the power supply problem of the gear shifting motor and reducing the maintenance difficulty.

[0089] The gear shifting motor is a high-speed and low-torque micro motor, which needs to rotate a large number of turns to drive the rotary control member 53 to rotate by a certain angle. This is not conducive to setting a sensor to obtain gear shifting information. Therefore, a gear shifting feedback device 13 is arranged to obtain gear shifting information. Figure 13 The schematic diagram of the rotation speed mixing mechanism 7 and the gear shifting feedback device 13. The gear shifting feedback device 13 includes a plurality of rows of Hall elements 131 and magnets 133. The driving device 6 is connected to the driving device speed reduction mechanism 12, which is used to convert the high rotation speed of the driving device 6 into a low rotation speed at 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.

[0090] The driving device speed reduction mechanism 12 includes a speed reduction sun gear 121, a speed reduction planetary gear 122, a speed reduction planet carrier 123 and a speed reduction ring gear 124. The speed reduction planetary gear 122 is rotatably mounted on the speed reduction planet carrier 123, and the speed reduction planetary gear 122 is meshed with the speed reduction sun gear 121 and the speed reduction ring gear 124, respectively. The speed reduction sun gear 121 is fixedly connected to the driving device 6, the magnet 133 is arranged on the speed reduction ring gear 124, and the speed reduction planet carrier 123 is fixed to the shell 1. The speed reduction sun gear 121 serves as the input end of the driving device speed reduction mechanism 12, and the speed reduction ring gear 124 serves as the output end of the driving device speed reduction mechanism 12. The rotation speed of the speed reduction ring gear 124 is the rotation speed of the speed reduction sun gear 121 divided by the transmission ratio of the driving device speed reduction mechanism 12.

[0091] Figure 14 The structure of the gear shifting feedback device 13 is shown in the schematic diagram. A plurality of Hall elements 131 are evenly spaced along the circumference of the driving device speed reduction mechanism 12 and are welded on the circuit board 132. The manual transmission has seven gears, so seven Hall elements 131 are provided. The pulse signal obtained by the uppermost Hall element 131 sensing the magnet 133 is defined as one gear, and the other Hall elements 131 are defined in turn as two gears to seven gears in counterclockwise order.

[0092] When the shift mechanism 5 performs a shift operation, the driving device 6 simultaneously drives the shift mechanism 5, the rotation speed mixing mechanism 7 and the driving device reduction mechanism 12 to rotate, the reduction gear ring 124 of the driving device reduction mechanism 12 rotates counterclockwise, and the rotation angle is to the corresponding Hall element 131 of the magnet 133 installed on the reduction gear ring 124 opposite to the third gear, then the gear position of the shift mechanism 5 is judged to be the third gear. The other gears are the same.

[0093] In order to facilitate the arrangement of the gear feedback device 13, the maximum angle of the plurality of rows of Hall elements 131 is not more than 360 degrees, that is, the angle from the Hall element 131 corresponding to the first gear to the Hall element 131 corresponding to the seventh gear is the maximum angle, and the maximum angle is not more than 360 degrees, which is to make the circuit board 132 design and installation more reasonable, and also reduce the complexity of the gear feedback device 13. Figure 14 In the embodiment, the Hall elements 131 are arranged along the radial direction of the reduction gear ring 124, and in addition, the Hall elements 131 can also be arranged along the axial direction of the reduction gear ring 124.

[0094] The application also provides a mid-drive motor, which comprises the above-mentioned intermediate shaft transmission, so that the mid-drive motor has both gear shifting function and electric assist function. Figure 15 As shown in the figure, the difference from the intermediate shaft transmission is that the assist motor 10 and the assist motor reduction mechanism 11 are additionally provided, the output shaft of the assist motor 10 is parallel to the axis of the intermediate shaft 2, and the assist motor 10 is connected to the first gear set 41 of the transmission mechanism 4 through the assist motor reduction mechanism 11.

[0095] When the assist motor 10 works, in addition to the torque of the rider's pedaling, the torque generated by the assist motor 10 is also added, and the two torques are output to the front sprocket 92, so that the rider can obtain higher riding speed or longer riding distance in a labor-saving riding mode.

[0096] Compared with the rear-mounted motor (hub motor) with gear shifting function, the mid-drive motor with gear shifting function has the structure of the transmission not on the rear wheel but on the frame, so the impact on the rough road will not be directly transmitted to the hub through the rim and spokes, but also needs to be transmitted through the frame, and the frame has a certain effect of absorbing vibration, greatly reducing the impact force, and relatively not easily affected by external force, not easily bumped, so that the mid-drive motor is more durable.

[0097] In addition, the vehicle with the middle motor is also provided with a speed feedback device, for example, a GPS chip is added to obtain positioning information and the speed of the vehicle is obtained through calculation, in the automatic mode, the rider does not need to operate, the middle transmission performs the gear shifting operation according to the speed of the vehicle, for example, when the speed of the vehicle reaches ten kilometers per hour, the gear is automatically shifted from first gear to second gear, for example, when the speed of the vehicle is reduced to less than ten kilometers per hour, the gear is automatically shifted from second gear to first gear. The rider can switch to the manual mode to freely change the gear position according to the actual road conditions, improve the flexibility of riding, and switch to the free mode to automatically change the gear position, improve the comfort of riding.

[0098] Alternatively, the middle motor is provided with a pedal frequency sensor and a torque sensor, the size of the pedaling torque and the speed of the pedaling frequency of the rider are obtained, the rider is in the uphill state, the flat ground rapid acceleration and deceleration state, the flat ground slow acceleration and deceleration state, and the downhill state are comprehensively judged according to the internal algorithm, and the driving device 6 is automatically controlled to shift gears, so as to realize the effect of automatic gear shifting.

[0099] In the description of the present specification, the description of the terms "one embodiment", "certain embodiments", "illustrative embodiment", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be appropriately combined in any one or more embodiments or examples.

[0100] The above only describes some embodiments of the present application. For those skilled in the art, without departing from the inventive concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application.

Claims

1. A mid-shaft transmission, characterized in that, include: The central axle (2) is rotatably supported on the frame, and torque is input from the central axle (2); The secondary shaft (3) is hollow and parallel to the central shaft (2); The transmission mechanism (4) is connected to the central shaft (2) and the secondary shaft (3) respectively, and has at least two transmission ratios; The drive unit (6) is connected to the shifting mechanism (5) and is housed inside the sub-shaft (3); The shifting mechanism (5) is linked with the transmission mechanism (4) and is used to change the transmission ratio of the transmission mechanism (4); The front sprocket (92) is fixed to the transmission mechanism (4) and outputs torque.

2. The central shaft transmission according to claim 1, characterized in that, The shifting mechanism (5) includes at least two pawls (51), a reset member (52), and a rotation control member (53). The sub-shaft (3) has a groove (31). The pawl (51) is rotatably installed in the groove (31). One end of the reset member (52) abuts against the sub-shaft (3), and the other end of the reset member (52) abuts against the pawl (51). The outer circumferential surface of the rotation control member (53) is provided with a control groove (531), and the pawl (51) is located on the outside of the rotation control member (53). When the rotation angle between the rotation control component (53) and the countershaft (3) deflects, one end of the pawl (51) falls into the control groove (531), fixing the gear of the shifting mechanism (5) to the countershaft (3) to change the transmission ratio.

3. The central shaft transmission according to claim 2, characterized in that, The rotation control element (53) is disposed inside the sub-shaft (3), and the drive device (6) is disposed inside the rotation control element (53).

4. The central shaft transmission according to claim 2, characterized in that, The control groove (531) is a spiral groove (5311).

5. The central shaft transmission according to claim 2, characterized in that, The control slot (531) consists of at least two spirally arranged through slots (5312), which are opened along the circumference of the rotation control member (53), and adjacent through slots (5312) are not connected.

6. The central shaft transmission according to claim 2, characterized in that, It also includes a speed mixing mechanism (7), which is connected to the shifting mechanism (5), the countershaft (3) and the drive device (6) respectively; When the drive device (6) does not perform a shifting operation, the speed mixing mechanism (7) causes the shifting mechanism (5) and the sub-shaft (3) to rotate synchronously; when the drive device (6) performs a shifting operation, the speed mixing mechanism (7) causes the rotation control element (53) of the shifting mechanism (5) and the rotation angle of the sub-shaft (3) to deflect.

7. The central shaft transmission according to claim 6, characterized in that, The speed mixing mechanism (7) includes a first ring gear (71), a first sun gear (72), a planet carrier (73), a multi-planetary gear (74), a second ring gear (76), and a second sun gear (75). The multi-planetary gear (74) is rotatably connected to the planet carrier (73). The multi-planetary gear (74) meshes 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 to the rotation control member (53) of the shifting mechanism (5). The second ring gear (76) is connected to the countershaft (3). The first sun gear (72) is connected to the drive device (6). The second sun gear (75) is fixedly connected to the housing (1).

8. The central shaft transmission according to claim 7, characterized in that, The multi-planetary gear (74) is a double planetary gear (741), which includes a first planetary gear (7411) and a second planetary gear (7412) with the same number of teeth. The first planetary gear (7411) meshes with the first gear ring (71) and the first sun gear (72) respectively, and the second planetary gear (7412) meshes with the second gear ring (76) and the second sun gear (75) respectively.

9. The central shaft transmission according to claim 7, characterized in that, The multi-planetary gear (74) is a quad-planetary gear (742), which includes a third planetary gear (7421) and a sixth planetary gear (7424) with the same number of teeth, and a fourth planetary gear (7422) and a fifth planetary gear (7423) with the same number of teeth. The third planetary gear (7421) has fewer teeth than the fourth planetary gear (7422). The third planetary gear (7421) meshes with the first gear ring (71), the fourth planetary gear (7422) meshes with the first sun gear (72), the sixth planetary gear (7424) meshes with the second gear ring (76), and the fifth planetary gear (7423) meshes with the second sun gear (75).

10. The central shaft transmission according to claim 1, characterized in that, It also includes a gear position feedback device (13), which includes a plurality of Hall elements (131) arranged in a row and a magnet (133). The drive device (6) is connected to the drive device reduction mechanism (12). The drive device reduction mechanism (12) includes a reduction sun gear (121), a reduction planetary gear (122), a reduction planetary carrier (123), and a reduction ring gear (124). The reduction planetary gear (122) is rotatably mounted on the reduction planetary carrier (123). The reduction planetary gear (122) meshes with the reduction sun gear (121) and the reduction ring gear (124) respectively. The reduction sun gear (121) is fixedly connected to the drive device (6). The magnet (133) is disposed on the reduction ring gear (124). The reduction planetary carrier (123) is fixed to the outer shell (1). The Hall element (131) senses the magnetic field strength of the magnet (133) mounted on the reduction ring gear (124) to obtain a pulse signal and determines the gear position to which the shifting mechanism (5) has rotated.

11. The central shaft transmission according to claim 10, characterized in that, The maximum angle of the multiple Hall elements (131) arranged in a row does not exceed 360 degrees.

12. The central shaft transmission according to claim 1, characterized in that, The drive device (6) is a shift motor, which is fixedly connected to the housing (1).

13. The central shaft transmission according to claim 1, characterized in that, The transmission mechanism (4) includes a first gear set (41) and a second gear set (42). The torque is input from the central shaft (2), passes through the first gear set (41) and the second gear set (42) in sequence, and is output to the front sprocket (92).

14. The central shaft transmission according to claim 13, characterized in that, The first gear set (41) includes a first driving gear (411) and a first driven gear (412) that mesh with each other. The first driving gear (411) is fixed to the central shaft (2), and the first driven gear (412) is fixed to the countershaft (3). The second gear set (42) includes a second driving gear (421) and a second driven gear (422) meshing with each other. The second driving gear (421) is movably connected to the countershaft (3). The second driving gear (421) is fixed or movable relative to the countershaft (3) through the shifting mechanism (5) to perform shifting. The second driven gear (422) is fixedly connected to a transmission sleeve (91), and the transmission sleeve (91) is movably connected to the central shaft (2).

15. The central shaft transmission according to claim 14, characterized in that, The second driving gear (421) and the second driven gear (422) are provided in multiples. The second driving gear (421) with the smallest number of teeth is fixed to the countershaft (3). The second driven gear (422) with the largest number of teeth is provided with a one-way clutch (93) between it and the transmission sleeve (91).

16. A mid-drive motor, comprising a mid-shaft gearbox as described in any one of claims 1-15, characterized in that, It also includes a power assist motor (10) and a power assist motor reduction mechanism (11), wherein the power assist motor (10) is connected to the transmission mechanism (4) through the power assist motor reduction mechanism (11).

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