Transmission and bicycle

Abstract

The utility model relates to a bicycle technical field, specifically disclose a transmission mechanism and bicycle, the transmission mechanism includes crank assembly and tooth disc, crank assembly includes left crank, right crank and middle axle, one of left crank and right crank is integrally formed with middle axle, and the other is detachably fixedly connected with middle axle. Any one of left crank and right crank is integrally formed with tooth disc, can reduce the assembly interface number, reduce the transmission loss caused by the assembly gap, omit tooth disc gear milling assembly, reduce middle axle and corresponding crank key groove processing etc. Step, simplify assembly process. Tooth disc and corresponding crank integrally formed, reduce the looseness risk between tooth disc and corresponding crank, avoid the tooth slip or fatigue fracture situation that may appear in traditional bolt fixing mode, reduce the stress concentration point in traditional assembly structure, improve overall structural strength, drive more directly, power transmission efficiency is higher, still can keep high accuracy after long -term use, reduce maintenance frequency.

Description

Technical Field

[0001] This utility model relates to the field of bicycle technology, and in particular to a transmission mechanism and a bicycle. Background Technology

[0002] Chains and sprockets are a common type of transmission mechanism. Different sprockets are placed at the power end and the output end, and the two ends are connected by a chain. The power end uses a power mechanism to rotate the sprockets, which in turn drives the chain to move. The chain drives the sprockets at the output end to rotate, thus outputting power.

[0003] In related technologies, the crankshaft, as a rotary motion mechanism, often includes a central shaft. Crankshafts are typically manufactured using high-hardness, wear-resistant materials through milling and gear hobbing. Crankshafts are manufactured using lightweight materials through turning, drilling, or welding. The central shaft is manufactured using high-hardness, wear-resistant materials through turning and other methods.

[0004] In chain drives, components such as the chain sprocket, crank, and bottom shaft need to be manufactured separately and then assembled together using keyway fitting or bolt fastening. This requires alignment and calibration, which can lead to additional process costs, loss of machining accuracy due to assembly gaps, potential assembly strength defects, and reduced lifespan or performance due to wear at the assembly points. Utility Model Content

[0005] The purpose of this utility model is to provide a transmission mechanism and a bicycle to solve the problem in the related technology that the components of chain drive need to be processed and manufactured separately and then assembled, resulting in many process steps and easy assembly gaps between assembled components.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, this utility model provides a transmission mechanism for driving a rotating component to rotate, the transmission mechanism comprising:

[0008] A crank assembly includes a left crank, a right crank, and a bottom bracket, wherein one of the left crank and the right crank is integrally formed with the bottom bracket, and the other is detachably and fixedly connected to the bottom bracket;

[0009] The crank, wherein either the left crank or the right crank is integrally formed with the crank, is used for transmission connection with the rotating component.

[0010] In one embodiment, the left crank and the central shaft are 3D printed as a single unit; or...

[0011] The right crank and the central shaft are 3D printed as a single unit.

[0012] In one embodiment, either the left crank or the right crank is 3D printed as a single unit with the crankset.

[0013] In one embodiment, the left crank extends in the same radial direction as the right crank extends in the same radial direction as the central axis; or,

[0014] The left crank extends in the radial direction of the central axis in the opposite direction to the right crank extending in the radial direction of the central axis; or,

[0015] The left crank extends in the radial direction of the central axis and intersects the right crank in the radial direction of the central axis.

[0016] In one embodiment, the one of the left crank and the right crank that is not integrally formed with the bottom bracket is bonded, snap-fitted or threaded to the bottom bracket.

[0017] In one embodiment, the transmission mechanism further includes a base, through which the central shaft passes, and the central shaft is rotatably connected to the base via a bearing, and the central shaft is fixedly connected to the bearing.

[0018] In one embodiment, the toothed disc includes multiple disc bodies arranged coaxially, and the radial dimensions of the multiple disc bodies increase or decrease sequentially in the axial direction of the toothed disc.

[0019] In one embodiment, the transmission mechanism includes a chain, and the chain sprocket forms a chain drive with the rotating member via the chain;

[0020] The number of chains is the same as the number of disks, and their positions are correspondingly set.

[0021] Alternatively, the number of chains is less than the number of discs, and the transmission mechanism further includes a shifting structure for switching the position of the chains between different discs.

[0022] In one embodiment, the crankset is provided with at least two sets, a portion of the crankset of the at least two sets is disposed on the left crank and integrally formed with the left crank, and another portion is disposed on the right crank and integrally formed with the right crank.

[0023] Secondly, this utility model provides a bicycle, including the transmission mechanism of any of the above-mentioned solutions, wherein the rotating component includes a rear wheel hub and a rear wheel chainring, the rear wheel chainring is disposed on the rear wheel hub, and the chainring is connected to the rear wheel chainring in a transmission manner.

[0024] The beneficial effects of this utility model are as follows:

[0025] This utility model provides a transmission mechanism that integrates one of the left and right cranks with the bottom shaft, or integrates either the left or right crank with the crankset. This reduces the number of assembly interfaces, lowers transmission losses due to assembly clearances, eliminates the need for milling the crankset teeth before assembly, and reduces steps such as machining the keyways of the bottom shaft and corresponding cranks, simplifying the assembly process. The integrated molding of the crankset and corresponding cranks reduces the risk of loosening between them, avoids stripping or fatigue fracture that may occur with traditional bolt fixing methods, reduces stress concentration points in traditional assembly structures, improves overall structural strength, provides more direct transmission, higher power transmission efficiency, maintains high precision even after long-term use, and reduces maintenance frequency. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the overall structure of the transmission mechanism from the left side in an embodiment of this utility model.

[0027] Figure 2 This is a schematic diagram of the overall structure of the transmission mechanism from the right side view in an embodiment of this utility model;

[0028] Figure 3 This is a schematic diagram of the connection structure between the crank and the right crank in an embodiment of this utility model;

[0029] Figure 4 This is a schematic diagram showing the positional relationship between the toothed disc and the base in an embodiment of this utility model;

[0030] Figure 5 This is a schematic diagram showing the positional relationship between the base, the central shaft, and the left crank in an embodiment of this utility model;

[0031] Figure 6 This is a schematic diagram showing the positional relationship between the left crank and the central shaft in an embodiment of this utility model;

[0032] Figure 7 This is a schematic diagram of the base structure in an embodiment of the present utility model.

[0033] In the picture:

[0034] 1. Crank assembly; 11. Left crank; 12. Right crank; 13. Bottom bracket;

[0035] 2. Crankset; 21. Crankset body; 22. Teeth; 23. Support frame;

[0036] 3. Base. Detailed Implementation

[0037] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0038] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0039] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0040] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0041] like Figures 1 to 4 As shown, an embodiment of the first aspect of this utility model provides a transmission mechanism for driving a rotating component to rotate. The transmission mechanism includes a crank assembly 1 and a chainring 2. The crank assembly 1 includes a left crank 11, a right crank 12, and a bottom bracket 13. One of the left crank 11 and the right crank 12 is integrally formed with the bottom bracket 13, and the other is detachably fixedly connected to the bottom bracket 13. Either the left crank 11 or the right crank 12 is integrally formed with the chainring 2, which is used for transmission connection with the rotating component.

[0042] This configuration, by integrating one of the left crank 11 and right crank 12 with the central shaft 13, and integrating either the left crank 11 or right crank 12 with the chainring 2, reduces the number of assembly interfaces, lowers transmission losses due to assembly gaps, eliminates the need for milling the chainring 22 teeth before assembly, and reduces steps such as machining the keyways of the central shaft 13 and corresponding cranks, simplifying the assembly process. The chainring 2 and corresponding cranks are integrally formed, reducing the risk of loosening between them, avoiding stripping or fatigue fracture that may occur with traditional bolt fixing methods, reducing stress concentration points in traditional assembly structures, improving overall structural strength, resulting in more direct transmission, higher power transmission efficiency, and maintaining high precision even after long-term use, reducing maintenance frequency. This solves the problem in related technologies where chain drives require separate manufacturing and assembly of components, resulting in numerous steps and assembly gaps between assembled parts.

[0043] Optionally, one of the left crank 11 and the right crank 12 can be integrally formed with the bottom bracket 13, and either of the left crank 11 and the right crank 12 can be integrally formed with the chainring 2 via 3D printing. That is, one of the left crank 11 and the right crank 12 and the bottom bracket 13 are both additive structures, and either of the left crank 11 and the right crank 12 and the chainring 2 can also be additive structures. Both the crank assembly 1 and the chainring 2 can be made of stainless steel, titanium alloy, or aluminum alloy through additive manufacturing. Alternatively, one of the left crank 11 and the right crank 12 can be integrally formed with the bottom bracket 13, and either of the left crank 11 and the right crank 12 can be integrally formed with the chainring 2 via casting, or it can also be integrally formed via a composite process combining forging and welding.

[0044] Optionally, the left crank 11 and the bottom bracket 13 are integrally formed, and the chainring 2 and the right crank 12 are integrally formed. The bottom bracket 13 and the right crank 12 can be detachably and fixedly connected by means of interference fit, threaded connection or keyway connection.

[0045] Among them, 3D printing, also known as additive manufacturing technologies (AM), constructs three-dimensional objects by adding materials layer by layer. The specific steps are designing a model, slicing, and printing layer by layer. Specifically, a three-dimensional model is created by integrating one of the left crank 11 and the right crank 12 with the central shaft 13 as a whole, and either the left crank 11 or the right crank 12 with the chainring 2 as a whole. The three-dimensional model is then sliced ​​into multiple two-dimensional layers to generate a printing path. Based on the slicing data, the 3D printer adds materials layer by layer to construct the entire solid object. 3D printing is an existing technology. In this embodiment, one of the left crank 11 and the right crank 12 is integrally 3D printed with the central shaft 13, and either the left crank 11 or the right crank 12 is integrally 3D printed with the chainring 2. This reduces the precision loss caused by assembly gaps, improves the overall assembly precision of the transmission mechanism, and also reduces the strength loss caused by assembly connection points. The processing speed is fast, the pollution is low, and the cost is low.

[0046] like Figures 1 to 4 As shown, in some embodiments, the left crank 11 and the central shaft 13 are 3D printed as a single unit. Compared to bolted connections or keyway fittings, the 3D printed single-unit structure of the left crank 11 and the central shaft 13 simplifies the processing steps, reduces most of the processing and assembly steps, eliminates the need for additional tooling fixtures, and enables continuous force transmission through the integrated design. This reduces the number of mechanical connection interfaces, improves torsional strength, reduces stress concentration points, and lowers the risk of fatigue fracture. Furthermore, the high processing precision ensures that the rotation centers of the central shaft 13 and the left crank 11 coincide, reducing radial runout. 3D printing can also manufacture hollow cranks that are impossible with traditional processes, achieving significant weight reduction while maintaining strength. For example, the interior of the left crank 11 can be designed as a hollow honeycomb structure, and the central shaft 13 can use a gradually varying wall thickness to thin the non-stressed areas.

[0047] like Figures 4 to 7 As shown, or similarly, the right crank 12 and the central shaft 13 are 3D printed as a single unit, which simplifies the processing steps, enables continuous force transmission, reduces mechanical connection interfaces, improves torsional strength, reduces stress concentration points, and lowers the risk of fatigue fracture. High processing precision ensures that the rotation centers of the central shaft 13 and the right crank 12 coincide, reducing radial runout. Significant weight reduction is achieved while maintaining strength. In this embodiment, one of the left crank 11 and the right crank 12 in the crank assembly 1 is 3D printed as a single unit with the central shaft 13, allowing for more rational material distribution and ensuring a lighter weight without sacrificing strength. 3D printing offers fast processing speed, low pollution, and low cost.

[0048] Optionally, a reinforcing rib or mesh connection structure may be provided between the left crank 11 and the central shaft 13 or between the right crank 12 and the central shaft 13 to facilitate reinforcement of the transition position.

[0049] In some embodiments, the radial extension direction of the left crank 11 on the central shaft 13 is the same as that of the right crank 12 on the central shaft 13. This results in more symmetrical leg movements during pedaling, with consistent foot trajectories and more even force distribution on both legs, reducing body sway caused by asymmetrical movements. Alternatively, the radial extension direction of the left crank 11 on the central shaft 13 is opposite to that of the right crank 12 on the central shaft 13. The left and right cranks 11 and 12 can be driven alternately, and their centrally symmetrical torque distribution is uniform, reducing uneven wear on the central shaft 13 bearing. Alternatively, the radial extension direction of the left crank 11 on the central shaft 13 intersects with that of the right crank 12 on the central shaft 13.

[0050] Optionally, when the radial extension direction of the left crank 11 in the center axle 13 intersects the radial extension direction of the right crank 12 in the center axle 13, the angle between the left crank 11 and the right crank 12 can be any value other than 0 degrees and 180 degrees. For example, the angle between the left crank 11 and the right crank 12 can be from 1 degree to 179 degrees, and the angle between the left crank 11 and the right crank 12 can be slightly greater than or slightly less than 180 degrees. Slightly offsetting the cranks can reduce the joint shear force during pedaling, and the asymmetrical angle can adapt to specific riding postures. The end of the left crank 11 away from the center axle 13 and the end of the right crank 12 away from the center axle 13 can be provided with the same or different grips, pedals, or connectors, which can be driven by external force to rotate the corresponding cranks as a whole.

[0051] like Figures 1 to 4 As shown, in some embodiments, either the left crank 11 or the right crank 12 is 3D printed as a single unit with the chainring 2, that is, the left crank 11 and the chainring 2 are 3D printed as a single unit, or the right crank 12 and the chainring 2 are 3D printed as a single unit. This allows the chainring 2 to be combined with the corresponding crank, eliminating the mechanical connection interface. Moreover, the 3D printing single unit has high processing precision, which facilitates the improvement of transmission accuracy and simplifies the processing procedure.

[0052] In some embodiments, the one of the left crank 11 and the right crank 12 that is not integrally formed with the central shaft 13 is connected to the central shaft 13 by adhesive bonding, snap-fitting, or threaded connection, which is convenient for connection and facilitates keeping the central shaft 13 and the corresponding crank fixed after connection, reducing relative movement between them.

[0053] like Figures 4 to 7As shown, in some embodiments, the transmission mechanism further includes a base 3, a central shaft 13 passing through the base 3, and the central shaft 13 is rotatably connected to the base 3 through a bearing. The central shaft 13 is fixedly connected to the bearing, that is, the outer wall of the central shaft 13 can be connected to the base 3 through the bearing, so that the central shaft 13 can rotate flexibly around the axis relative to the base 3 without any other degrees of freedom.

[0054] Optionally, the outer wall of the central shaft 13 is interference-fitted with the inner hole of the bearing, and the central shaft 13 may be provided with protrusions or retaining rings at both ends of the bearing. The retaining elements can further prevent the central shaft 13 from shifting relative to the bearing.

[0055] When the transmission mechanism is applied to a bicycle, the base 3 can be a frame structure, and the bottom bracket 13 can be directly rotatably connected to the frame through bearings.

[0056] In some embodiments, each set of chainrings 2 includes multiple disc bodies 21, which are coaxially arranged. In the axial direction of the chainrings 2, the radial dimensions of the multiple disc bodies 21 increase or decrease one by one, which enables the axial layout to be compact and forms a gradient chainring 2. When the chain switches between the multiple disc bodies 21, it is convenient to fine-tune the gear ratio.

[0057] In some embodiments, the transmission mechanism includes a chain, and the toothed sprocket 2 forms a chain drive with the rotating component via the chain.

[0058] Optionally, the number of chains is the same as the number of discs 21 and their positions correspond, meaning the positions and numbers of chains and discs 21 are matched. One or more sets can be provided. When multiple sets of chains and discs 21 are provided, different chains can be connected to the same rotating component, thus distributing stress and torque. Alternatively, different chains can be connected to different rotating components, allowing a single crankset 2 to drive multiple rotating functional modules, facilitating multi-functional integration and high space utilization.

[0059] Optionally, the number of chains is less than the number of discs 21. The transmission mechanism also includes a shifting structure, which is used to switch the position of the chain between different discs 21 to perform shifting operations. This allows users to select the appropriate gear ratio according to different road conditions and riding needs, thereby improving transmission efficiency.

[0060] The shifting structure may include a shifter and a lever. The lever is movably mounted on the base 3. The shifter is connected to the lever. The shifter can be positioned in a location that is convenient for the user's hand to operate, such as the handlebar position of the frame. Rotating or sliding the shifter can drive the lever to move. The lever can move the chain to switch to different chainrings 21 for shifting.

[0061] like Figures 1 to 4As shown, in some embodiments, the disk body 21 is an integrally formed disk structure. The outer periphery of the disk body 21 has multiple teeth 22. The surface of the teeth 22 is a machined surface. The machined surface can be, but is not limited to, a milled surface, a ground surface, or a laser polished surface. After the teeth 22 and the disk body 21 are integrally formed, the surface roughness can be reduced and the wear rate can be reduced by machining the surface of the teeth 22.

[0062] Among them, the disk body 21 is a 3D printed one-piece disk structure, and the teeth 22 can be formed together with the disk body 21 by 3D printing. Only the surface of the teeth 22 needs to be further machined after completion, which reduces the complex teeth 22 shape processing process.

[0063] Optionally, the chainring 21 can be a ring-shaped plate structure. The chainring 21 and the corresponding left or right crank can be connected by a support frame 23. The support frame 23 can be a mesh structure. An arc transition is made at the connection position between the chainring 21 and the corresponding crank, which not only helps to reduce stress concentration, but also makes the chainring 2 as a whole form a lightweight design and reduces weight.

[0064] In some embodiments, the chainring 2 is provided with at least two sets. A portion of the chainring 2 is integrally formed with the left crank 11, and another portion is integrally formed with the right crank 12. This arrangement allows the left crank 11 to drive the chainring 2 corresponding to it, and the right crank 12 to drive the chainring 2 corresponding to it, enabling multiple drive groups. Even if a single group fails, transmission can still be maintained. Furthermore, the multiple chainring 2 groups can share the torque, thus distributing the load and reducing wear. Each chainring 2 group can also have a different number of teeth, facilitating multi-speed shifting and reducing the number of sprockets on the rear wheel. Compared to a single-sided large tooth 22 which is more likely to cause chain tilting, this embodiment can also use chainring 2 on both sides to reduce wear caused by chain tilting. The double-sided chainring 2 can balance the torsional stress of the left crank 11 and right crank 12, reducing uneven wear on the bottom bracket bearing 13.

[0065] In this embodiment, the positions and numbers of the chain and the chainring 2 are matched, and one or more sets can be provided. When at least two sets of chain and chainring 2 are provided, the at least two sets of chain and chainring 2 can be set on the left and right sides respectively. The chain drive on both sides allows each chain to bear only part of the torque, reducing the risk of single chain stretching and deformation. Moreover, the chain drive has high accuracy and can be mutually corrected. One or more rotating components can be provided. At least two sets of chainring 2 can be connected to the same rotating component through the chain, which facilitates increasing the driving force, reducing the single chain load, and reducing the torque. Alternatively, at least two sets of chainring 2 can also be connected to different rotating components through the chain, which facilitates a single crank assembly 1 to drive multiple rotating functional modules, making it easy to achieve multi-functional integration and high space utilization.

[0066] A second aspect of the present invention provides a bicycle including the transmission mechanism in any of the above embodiments. The rotating component includes a rear wheel hub and a rear wheel chainring 2. The rear wheel chainring 2 is disposed on the rear wheel hub and is connected to the rear wheel chainring 2 in a transmission manner.

[0067] In some embodiments, the number of rear wheel chainrings 2 may be the same as the number of chainrings 2, and their positions may correspond front and rear, facilitating corresponding transmission connections.

[0068] Because it includes the transmission mechanism described above, the bicycle of this utility model embodiment has all the advantages and beneficial effects of the above embodiments, which will not be repeated here.

[0069] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A transmission mechanism for driving a rotating component to rotate, characterized in that, The transmission mechanism includes: A crank assembly includes a left crank, a right crank, and a bottom bracket, wherein one of the left crank and the right crank is integrally formed with the bottom bracket, and the other is detachably and fixedly connected to the bottom bracket; The crank, wherein either the left crank or the right crank is integrally formed with the crank, is used for transmission connection with the rotating component.

2. The transmission mechanism according to claim 1, characterized in that, The left crank and the central shaft are integrally formed by 3D printing; or... The right crank and the central shaft are 3D printed as a single unit.

3. The transmission mechanism according to claim 1, characterized in that, Either the left crank or the right crank is integrally formed with the crankset using 3D printing.

4. The transmission mechanism according to claim 1, characterized in that, The left crank extends in the same radial direction as the right crank on the central axis; or, The left crank extends in the radial direction of the central axis in the opposite direction to the right crank extending in the radial direction of the central axis; or, The left crank extends in the radial direction of the central axis and intersects the right crank in the radial direction of the central axis.

5. The transmission mechanism according to claim 1, characterized in that, The left crank and the right crank that are not integrally formed with the central shaft are connected to the central shaft by adhesive, snap-fit ​​or threaded connection.

6. The transmission mechanism according to claim 1, characterized in that, The transmission mechanism also includes a base, through which the central shaft passes, and the central shaft is rotatably connected to the base via a bearing, and the central shaft is fixedly connected to the bearing.

7. The transmission mechanism according to any one of claims 1-6, characterized in that, The toothed disc includes multiple disc bodies, which are coaxially arranged. In the axial direction of the toothed disc, the radial dimensions of the multiple disc bodies increase or decrease sequentially.

8. The transmission mechanism according to claim 7, characterized in that, The transmission mechanism includes a chain, and the toothed chain forms a chain drive with the rotating component through the chain; The number of chains is the same as the number of disks, and their positions are correspondingly set. Alternatively, the number of chains is less than the number of discs, and the transmission mechanism further includes a shifting structure for switching the position of the chains between different discs.

9. The transmission mechanism according to claim 1, characterized in that, The crankset is provided with at least two sets, and a portion of the crankset is provided on the left crank and integrally formed with the left crank, while another portion is provided on the right crank and integrally formed with the right crank.

10. A bicycle, characterized in that, The transmission mechanism includes any one of claims 1-9, wherein the rotating component includes a rear wheel hub and a rear wheel sprocket, the rear wheel sprocket is disposed on the rear wheel hub, and the sprocket is connected to the rear wheel sprocket in a driving connection.

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