Double-helix crank structure and bicycle

Abstract

The double-helix crank structure comprises a crank and a pair of rocker arms, the tail ends of the two rocker arms are hinged through a root shaft so that the two rocker arms can relatively rotate with the root shaft as the axis, the root shaft is used for being fixedly connected with a frame of a bicycle, and the head ends of the rocker arms are used for being hinged to pedals through shafts; the middle of the crank is fixedly connected with a main shaft, the main shaft is used for being rotationally connected with a frame of a bicycle and used for being in transmission connection with a driving wheel of the bicycle, the main shaft is parallel to a root shaft, the two ends of the crank are symmetrically and rotationally connected with the two rocker arms in a sliding mode, and the sliding direction is arranged in the length direction of the rocker arms; when the crank is perpendicular to any rocker arm, the included angle between the crank and the other rocker arm is an acute angle. The problem that a dead zone exists in an existing bicycle driving mechanism can be solved.

Description

Technical Field

[0001] The utility model relates to the technical field of bicycle drive structures, and particularly relates to a double-helix crank structure and a bicycle. Background Art

[0002] At present, a conventional bicycle drive structure includes a rocker arm, a main shaft, and pedals. The tail end of the rocker arm is connected to the main shaft, and the pedal shaft is hinged to the head end of the rocker arm. By stepping on the pedals, the rocker arm can be driven to rotate around a circular track with the main shaft as the axis, and then the main shaft is driven to rotate, so as to drive the driving gear to rotate through the rotating main shaft, thereby driving the driving wheel to rotate.

[0003] The bicycle with the above structure has the following problems: (1) The torque at the top dead center and bottom dead center is very small, and when the foot is at the dead center position, there will be a feeling of "being unable to exert strength"; (2) The optimal power generation angle is only about 120°; (3) The time for the foot to do work is only one-third, and the rest is useless work.

[0004] Logically speaking, it seems that increasing the length of the crank can enable a bicycle rider to output greater force when riding. However, in actual riding, a longer crank means a longer stroke of the foot, which will instead make the rider more tired. Even some riders replace the crank with a shorter one in order to achieve a faster speed and improve their race results by increasing their pedaling frequency. Therefore, how to eliminate the dead zone of the drive mechanism is an urgent problem to be solved. Summary of the Utility Model

[0005] The purpose of the utility model is to provide a double-helix crank structure to solve the problem that the existing bicycle drive mechanism has a dead zone.

[0006] The utility model is realized by the following technical solutions:

[0007] A double-helix crank structure includes: a pair of rocker arms, the tail ends of the two rocker arms are hinged by a root shaft so that the two rocker arms can rotate relative to each other with the root shaft as the axis, the root shaft is used for fixedly connecting with the frame of the bicycle, and the head end of the rocker arm is used for hinging the pedals; a crank, the middle part of the crank is fixedly connected with a main shaft, the main shaft is used for rotatably connecting with the frame of the bicycle and for drivingly connecting with the driving wheel of the bicycle, the main shaft is arranged parallel to the root shaft, and the two ends of the crank are symmetrically slidably and rotatably connected with the two rocker arms, and the sliding direction is arranged along the length direction of the rocker arm; when the crank is perpendicular to any one of the rocker arms, the included angle between the crank and the other rocker arm is an acute angle.

[0008] Optionally, the crank includes a first crank and a second crank, and the first crank and the second crank have the same shape; the tail ends of the first crank and the second crank are respectively connected to the main shaft so that the rotation planes of the first crank and the second crank are arranged in parallel; an installation gap is reserved between the tail end of the first crank and the tail end of the second crank along the axial direction of the main shaft, and the installation gap is used to clamp the driving gear of the bicycle; the head ends of the first crank and the second crank are respectively slidably and rotatably connected to the two rocker arms.

[0009] Optionally, the first crank and the second crank are collinear and arranged in opposite directions.

[0010] Optionally, a chute is formed in the rocker arm along the length direction; a sliding shaft is provided at the end of the crank, and the sliding shaft is arranged parallel to the main shaft, and the two sliding shafts are respectively slidably and rotatably connected to the two chutes.

[0011] Optionally, a bearing is rotatably sleeved on the sliding shaft, and the outer wall of the bearing is slidably matched with the corresponding chute.

[0012] Optionally, the rocker arm includes a transmission section and a force application section, and both the transmission section and the force application section are linear; one end of the transmission section is fixedly connected to the force application section, and the included angle between the transmission section and the force application section is an obtuse angle; the chute is formed in the transmission section and extends along the length direction of the transmission section; a root shaft is arranged at the end of the transmission section far from the force application section; the end of the force application section far from the transmission section is used for axially hinging a pedal; when one transmission section is perpendicular to the crank, the included angle between the other transmission section and the crank is an acute angle.

[0013] Optionally, when the first transmission section is perpendicular to the crank, the force application section connected to the second transmission section is arranged parallel to the first transmission section.

[0014] Optionally, the ratio of the length of the crank to the length of the transmission section ≤ 1:1.4.

[0015] Optionally, a support arm is connected to the root shaft, and the support arm is used for fixedly connecting to the frame of the bicycle so that the point where the root shaft is located is tangent to the lowest point of the driving gear of the bicycle.

[0016] A bicycle, comprising: a frame, the frame is provided with a driving wheel and a driven wheel; any one of the above double - spiral crank structures, the root shaft is fixedly connected to the frame, the main shaft is rotatably connected to the frame, the main shaft is coaxially and fixedly connected with a driving gear, the driving gear is in transmission connection with the driving wheel, and the head end of the rocker arm is axially hinged with a pedal.

[0017] Compared with the prior art, the utility model has the following advantages and beneficial effects:

[0018] A double - spiral crank structure provided by the utility model, by setting a pair of rocker arms, setting the ends of both of them to be axially hinged by a root shaft, and at the same time setting a main shaft and a crank, making the two ends of the crank symmetrically slide and rotatably connected with the two rocker arms. Compared with the existing single - shaft (only the main shaft) type of driving mechanism, an additional root shaft is added, changing the movement track of the rocker arm, making the end of the rocker arm with a footrest only make upper and lower reciprocating swings with a relatively small circumferential angle (acute angle), so that the force - exerting angle at any angle is a better force - exerting angle, always being able to do work smoothly, without dead points or dead zones, and not doing useless work; and, with the upper and lower reciprocating swings of the relatively small (acute - angle) circumferential angle of the rocker arm, the crank will rotate at a large angle (circumference), effectively increasing the angular velocity of the main shaft, that is, equivalent to increasing the angular velocity of the tire, which also improves the pedaling efficiency; through the mutual cooperation of the above - mentioned features, the double - spiral crank structure can effectively solve the problem of dead zones existing in the existing bicycle driving mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings described herein are used to provide a further understanding of the embodiments of the utility model, form a part of this application, and do not limit the embodiments of the utility model. In the drawings:

[0020] Figure 1 is a schematic diagram of the double - spiral crank structure provided by the embodiment of the utility model;

[0021] Figure 2 is a schematic diagram of the double - spiral crank structure provided by the embodiment of the utility model after removing the driving gear;

[0022] Figure 3 is a schematic diagram of the rocker arm of the double - spiral crank structure provided by the embodiment of the utility model;

[0023] Figure 4 is a schematic diagram of the bicycle provided by the embodiment of the utility model.

[0024] Marks in the drawings and corresponding component names:

[0025] 1 - frame; 2 - driving wheel; 3 - driven wheel; 4 - driving gear; 10 - rocker arm; 101 - sliding groove; 102 - transmission section; 103 - force - applying section; 11 - root shaft; 12 - support arm; 20 - crank; 201 - first crank; 202 - second crank; 21 - main shaft; 22 - sliding shaft. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] To make the objectives, technical solutions and advantages of the present utility model more clear and understandable, the present utility model will be further described in detail below in conjunction with embodiments and drawings. The illustrative embodiments and descriptions of the present utility model are only used to explain the present utility model and are not intended to limit the present utility model.

[0027] Please refer to Figures 1 to 3 , an embodiment of the present utility model provides a double - helix crank structure, which includes a pair of rocker arms 10. The tails of the two rocker arms 10 are pivotally connected by a root shaft 11, so that the two rocker arms 10 can rotate relative to each other with the root shaft 11 as the axis. The root shaft 11 is used for fixedly connecting with the frame of a bicycle. The head of the rocker arm 10 is used for pivotally connecting a pedal; secondly, it includes a crank 20. A main shaft 21 is fixedly connected to the middle of the crank 20. The main shaft 21 is used for rotatably connecting with the frame of the bicycle and for drivingly connecting with the driving wheel of the bicycle. The main shaft 21 is arranged parallel to the root shaft 11. The two ends of the crank 20 are symmetrically slidably and rotatably connected to the two rocker arms 10, and the sliding direction is arranged along the length direction of the rocker arm 10; when the crank 20 is perpendicular to any one of the rocker arms 10, the included angle between the crank 20 and the other rocker arm 10 is an acute angle.

[0028] The double - helix crank 20 structure provided in this embodiment, by setting a pair of rocker arms 10, pivotally connecting their tails by a root shaft 11, and at the same time setting a main shaft 21 and a crank 20, makes the two ends of the crank 20 symmetrically slidably and rotatably connected to the two rocker arms 10. Compared with the existing single - shaft (only the main shaft 21) type of driving mechanism, an additional root shaft 11 is added, which changes the movement trajectory of the rocker arm 10, making the end of the rocker arm 10 with the pedal only make reciprocating up - and - down swings with a relatively small circular angle (acute angle). So that at any angle during power generation, it is a better power - generating angle, and it can always smoothly do work, there is no dead point or dead zone, and no useless work will be done; moreover, as the rocker arm 10 makes reciprocating up - and - down swings with a relatively small (acute - angle) circular angle, the crank 20 will rotate at a large angle (circumference), effectively increasing the angular velocity of the main shaft 21, that is, equivalent to increasing the angular velocity of the tire, which also improves the pedaling efficiency; through the mutual cooperation of the above - mentioned features, the double - helix crank 20 structure can effectively solve the problem of dead zones existing in the existing bicycle driving mechanism.

[0029] To further explain the specific structure of the crank 20, the crank 20 includes a first crank 201 and a second crank 202, and the first crank 201 and the second crank 202 have the same shape; the tail ends of the first crank 201 and the second crank 202 are respectively connected to the main shaft 21, so that the rotation planes of the first crank 201 and the second crank 202 are arranged in parallel; an installation gap is reserved along the axial direction of the main shaft 21 between the tail end of the first crank 201 and the tail end of the second crank 202, and the installation gap is used to clamp the driving gear of the bicycle; the head ends of the first crank 201 and the second crank 202 are respectively slidably and rotatably connected to the two rocker arms 10.

[0030] With the above settings, the two ends of the crank 20 are not in the same plane, but in two parallel planes. Since the two rocker arms 10 are axially hinged, they must also be in an overlapping state. Therefore, the ends of the two are not in the same plane, and there is also a gap for setting the driving gear between the two rocker arms 10. Therefore, the distance between the two cannot be ignored. In order to enable the two ends of the crank 20 to effectively approach and connect to the two rocker arms 10, the split method can effectively solve this problem and provide a setting distance for the driving gear.

[0031] To improve the rationality of the structure of the crank 20 and reduce the length dimensions of the first crank 201 and the second crank 202 on the basis of ensuring the structural performance, the first crank 201 and the second crank 202 are collinear and arranged in opposite directions.

[0032] To further explain the specific structure of the sliding and rotating connection between the rocker arm 10 and the crank 20, a chute 101 is opened along the length direction of the rocker arm 10; a sliding shaft 22 is provided at the end of the crank 20, and the sliding shaft 22 is arranged parallel to the main shaft 21, and the two sliding shafts 22 are respectively slidably and rotatably connected to the two chutes 101.

[0033] With the above settings, the sliding shaft 22 is inserted into the chute 101, so that it can slide smoothly along the chute 101 and also rotate smoothly, thereby realizing the sliding and rotating connection between the crank 20 and the rocker arm 10.

[0034] It should be noted that the chute 101 penetrates the rocker arm 10 along the thickness direction of the rocker arm 10 to provide sufficient insertion depth for the sliding shaft 22.

[0035] To improve the smoothness of the sliding and rotating fit between the sliding shaft 22 and the chute 101, a bearing is rotatably sleeved on the sliding shaft 22, and the outer wall of the bearing is slidably matched with the corresponding chute 101.

[0036] To further explain the specific structure of the rocker arm 10, the rocker arm 10 includes a transmission section 102 and a force application section 103. Both the transmission section 102 and the force application section 103 are linear. One end of the transmission section 102 is fixedly connected to the force application section 103, and the angle between the transmission section 102 and the force application section 103 is an obtuse angle. The chute 101 is opened on the transmission section 102 and extends along the length direction of the transmission section 102. The root shaft 11 is provided at the end of the transmission section 102 away from the force application section 103. The end of the force application section 103 away from the transmission section 102 is used for shaft-hinging a footrest. When one transmission section 102 is perpendicular to the crank, the angle between the other transmission section 102 and the crank is an acute angle.

[0037] With the above settings, the rocker arm 10 is segmented into a transmission section 102 and a force application section 103, both of which are linear, and the angle between them is an obtuse angle, so as to extend the length of the rocker arm 10 while ensuring the distance between the ends of the two rocker arms 10, facilitating the setting of the footrest and the user's reciprocating stepping up and down. By defining that when one transmission section 102 is perpendicular to the crank 20, the angle between the other transmission section 102 and the crank 20 is an acute angle, the force application efficiency is further optimized.

[0038] It should be noted that the connection between the transmission section 102 and the force application section 103 adopts a spline connection, so that the angle between them can be adjusted according to actual needs, thereby adjusting the ground clearance of the force application section 103.

[0039] To further improve the rationality of the structure, when the first transmission section 102 is perpendicular to the crank, the force application section 103 connected to the second transmission section 102 is arranged parallel to the first transmission section 102.

[0040] To further optimize the force application efficiency, the ratio of the length of the crank 20 to the length of the transmission section 102 ≤ 1:1.4.

[0041] To further facilitate the user's stepping and force application, the root shaft 11 is connected with a support arm 12, and the support arm 12 is used for fixedly connecting with the frame of the bicycle, so that the point where the root shaft 11 is located is tangent to the lowest point of the driving gear of the bicycle.

[0042] With the above settings, first, by defining the set height of the root shaft 11, there is a certain height difference between the relative heights of the root shaft 11 and the main shaft 21, and the set height of the root shaft 11 is lower than that of the main shaft 21, so that the tangent line of the lowest point of the root shaft 11 and the driving gear is horizontal. Thus, the rocker arm 10 always switches between the up-tilted and horizontal states and will not incline downward, so that the user's feet can always have good force application conditions and will not have the feeling of stepping on empty space. And because the positions of the beam bodies of the vehicle frame are generally relatively fixed. For example, the beam body of the rear wheel generally passes horizontally through the axle of the rear wheel. Therefore, there is probably a height difference (distance difference) between it and the root shaft 11. By setting the support arm 12 to make up for this part of the distance difference, the root shaft 11 has a structural fulcrum for fixed connection.

[0043] Please refer to Figure 4 , the embodiment of the present utility model also provides a bicycle, including: a vehicle frame 1, the vehicle frame 1 is provided with a driving wheel 2 and a driven wheel 3; second, including any one of the above double-spiral crank structures, the root shaft 11 is fixedly connected to the vehicle frame 1, the main shaft 21 is rotatably connected to the vehicle frame 1, the main shaft 21 is coaxially and fixedly connected with a driving gear 4, the driving gear 4 is in transmission connection with the driving wheel 2, and the head end of the rocker arm 10 is pivotally connected with a foot pedal.

[0044] With the above settings, when the user pedals the foot pedal up and down reciprocally, the two rocker arms 10 can be driven to move up and down reciprocally alternately, thereby driving the crank 20 to rotate continuously, thereby driving the main shaft 21 to rotate continuously, thereby driving the driving gear 4 to rotate continuously, thereby driving the driving wheel 2 to rotate continuously, so that the bicycle can run.

[0045] It should be noted that in this embodiment, the driving gear 4 and the driving wheel 2 are connected by a chain. Specifically, the driving wheel 2 is coaxially connected with a plurality of driven gears, and the driven gears and the driving gear 4 are in transmission connection through a chain. When the driving gear 4 rotates, it drives the driven gears to rotate through the chain, thereby driving the driving wheel 2 to rotate.

[0046] It should be noted that the connection methods at the positions not mentioned in the above bicycle are all connected by existing technologies, and those skilled in the art can clearly implement the several connections not mentioned, which do not belong to the inventive points of this application, so they will not be elaborated here.

[0047] The above specific embodiments have further elaborated the purpose, technical solutions and beneficial effects of the present utility model. It should be understood that the above are only the specific embodiments of the present utility model and are not used to limit the protection scope of the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model should be included in the protection scope of the present utility model.

Claims

1. A double helical crank structure, characterized in that: include: A pair of rocker arms (10), the rear ends of the two rocker arms (10) being hinged by a root shaft (11) so that the two rocker arms (10) can rotate relative to each other about the root shaft (11), the root shaft (11) being used for being fixedly connected to a bicycle frame, and the head ends of the rocker arms (10) being used for hinged pedals; A crank (20), wherein a main shaft (21) is fixedly connected to the middle of the crank (20), and the main shaft (21) is used for rotationally connecting with the frame of the bicycle and for transmissionly connecting with the driving wheel of the bicycle, and the main shaft (21) is arranged parallel to the root shaft (11), and the two ends of the crank (20) are symmetrically connected to the two rocker arms (10) for sliding and rotation, and the sliding direction is arranged along the length direction of the rocker arms (10); When the crank (20) is perpendicular to any one of the rocker arms (10), the angle between the crank (20) and the other rocker arm (10) is an acute angle.

2. The double helical crank structure according to claim 1, characterized in that: The crank (20) comprises a first crank (201) and a second crank (202), wherein the first crank (201) and the second crank (202) have the same shape; The tail ends of the first crank (201) and the second crank (202) are respectively connected to the main shaft (21), so that the rotation plane of the first crank (201) and the rotation plane of the second crank (202) are arranged in parallel; An installation gap is reserved between the tail end of the first crank (201) and the tail end of the second crank (202) along the axial direction of the main shaft (21), and the installation gap is used to clamp a driving gear of the bicycle; The head end of the first crank (201) and the head end of the second crank (202) are respectively connected to the two rocker arms (10) in a sliding and rotational manner.

3. The double helical crank structure according to claim 2, characterized in that: The first crank (201) and the second crank (202) are arranged in the same line and in opposite directions.

4. The double helical crank structure according to any one of claims 1 to 3, characterized in that: The rocker arm (10) is provided with a slide groove (101) along the length direction; A sliding shaft (22) is provided at the end of the crank (20), and the sliding shaft (22) is arranged parallel to the main shaft (21). The two sliding shafts (22) are respectively connected to the two sliding grooves (101) in a sliding and rotatable manner.

5. The double helical crank structure according to claim 4, characterized in that: The sliding shaft (22) is rotatably sleeved with a bearing, and the outer wall of the bearing is slidably matched with the corresponding sliding groove (101).

6. The double helical crank structure according to claim 5, characterized in that: The rocker arm (10) comprises a transmission section (102) and a force-applying section (103), and both the transmission section (102) and the force-applying section (103) are linear; One end of the transmission section (102) is fixedly connected to the force-applying section (103), and the angle between the transmission section (102) and the force-applying section (103) is an obtuse angle; The slide groove (101) is provided in the transmission section (102) and extends along the length direction of the transmission section (102); The root shaft (11) is arranged at one end of the transmission section (102) away from the force-applying section (103); One end of the force-applying section (103) away from the transmission section (102) is used for pivoting the pedal; When one of the transmission sections (102) is perpendicular to the crank (20), the angle between the other transmission section (102) and the crank (20) is an acute angle.

7. The double helical crank structure according to claim 6, characterized in that: When the first transmission segment (102) is perpendicular to the crank, the force-applying segment (103) connected to the second transmission segment (102) is arranged parallel to the first transmission segment (102).

8. The double helical crank structure according to claim 7, characterized in that: The ratio of the length of the crank (20) to the length of the transmission section (102) is ≤1:1.

4.

9. The double helical crank structure according to claim 1, characterized in that: The root shaft (11) is connected with a support arm (12), and the support arm (12) is used for fixed connection with the frame of the bicycle so that the point where the root shaft (11) is located is tangent to the lowest point of the driving gear of the bicycle.

10. A bicycle, characterized in that: include: A vehicle frame (1), wherein the vehicle frame (1) is provided with a driving wheel (2) and a driven wheel (3); The double helical crank structure as described in any one of claims 1 to 9, wherein the root shaft (11) is fixedly connected to the frame (1), the main shaft (21) is rotationally connected to the frame (1), the main shaft (21) is coaxially fixedly connected to a driving gear (4), the driving gear (4) is transmission-connected to the driving wheel (2), and the front end of the rocker arm (10) is hinged with a pedal.

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