CN216508876U

CN216508876U - Double-driving bicycle

Info

Publication number: CN216508876U
Application number: CN202123429501.6U
Authority: CN
Inventors: 周炳坤
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-12-31
Filing date: 2021-12-31
Publication date: 2022-05-13
Anticipated expiration: 2031-12-31

Abstract

The utility model provides a double-drive bicycle. The dual-drive bicycle comprises a frame, a front wheel and a rear wheel, wherein the front wheel is connected to the front end of the frame, the rear wheel is connected to the rear end of the frame, the rear wheel is used for driving a main drive assembly and a pedal on the main drive assembly, the dual-drive bicycle further comprises a secondary drive assembly and a directional drive assembly, the secondary drive assembly is connected to the front wheel, the directional drive assembly is connected to the frame, the secondary drive assembly is connected to the main drive assembly in a driving mode, the directional drive assembly can be switched between a driving state and a separating state to control the main drive assembly and the secondary drive assembly in a driving mode or in a transmission separation mode. The double-drive bicycle can effectively solve the problems of slipping and abrasion of the double-drive bicycle due to the double force couple generated.

Description

Double-driving bicycle

Technical Field

The utility model belongs to the field of vehicles, and particularly relates to a dual-drive bicycle.

Background

In daily life, the bicycle is gradually the preferred mode of going out of people because of its excellent energy-concerving and environment-protective advantage, but when riding and meet the slope or muddy road, the rider often has to spend very big strength.

For solving above-mentioned problem partially at least, the designer has designed two drive bicycles of front and back wheel simultaneous drive for the frictional force that receives of front and back two-wheeled all converts power into, and power is provided only through the frictional force that receives of rear wheel in comparing in traditional bicycle, and two drive bicycles can effectively reduce the power of riding the person and spending when riding by bike, make two drive bicycles more laborsaving, quick at the in-process of riding.

However, because the front wheel and the rear wheel of the two-wheel drive bicycle are both power wheels, when the two-wheel drive bicycle has a rotation trend, the friction force borne by the front wheel and the friction force borne by the rear wheel form two force couples; with the gradual increase of the rotation angle, the front wheel rotates, namely the tendency of side turning is increased, and then the abrasion or side turning of the tire hub and the like are caused.

In view of the above, it is necessary to provide a new dual-drive bicycle to solve the above problems.

SUMMERY OF THE UTILITY MODEL

The utility model aims to provide a dual-drive bicycle, which effectively solves the problems of slipping and abrasion of the dual-drive bicycle due to the dual force couple.

In order to achieve the purpose of the utility model, the utility model provides a dual-drive bicycle, which comprises a frame, a front wheel connected to the front end of the frame, a rear wheel connected to the rear end of the frame, a main drive assembly for driving the rear wheel to rotate, a pedal connected to the main drive assembly, an auxiliary drive assembly connected to the front wheel and a directional transmission assembly connected to the frame, wherein the auxiliary drive assembly is in driving connection with the main drive assembly through the directional transmission assembly, and the directional transmission assembly can be switched between a transmission state and a separation state to control the transmission connection or transmission separation of the main drive assembly and the auxiliary drive assembly.

As a further improvement of the utility model, the frame comprises a main body, a front fork rotatably connected to the front end of the main body, a rear fork fixedly connected to the rear end of the main body, and a handlebar for driving the front fork to rotate, wherein a front wheel rotating shaft of the front wheel is rotatably connected to the end part of the front fork extending, and a rear wheel rotating shaft of the rear wheel is rotatably connected to the end part of the rear fork extending.

As a further improvement of the utility model, the directional transmission assembly comprises a transmission member connected to the front fork, a crank rotatably connected to the transmission member, and a gear transmission part connected to the crank.

As a further improvement of the present invention, the gear transmission portion includes a positioning frame disposed on the main body, a slide bar slidably connected to the positioning frame, and two bevel gears disposed on the slide bar, and the two bevel gears are disposed in a front-back staggered manner along an extending direction of the slide bar and are respectively engaged with the main driving assembly and the auxiliary driving assembly.

As a further improvement of the present invention, the transmission member is disposed in a plate shape and can move simultaneously with the front fork when the handlebar controls the front fork to rotate, and one end of the crank is rotatably connected to the transmission member through a bearing; the other end of the driving mechanism is connected with the sliding rod through a bearing so as to drive the two conical gears arranged on the sliding rod to be separated from or connected with the main driving assembly and/or the auxiliary driving assembly.

As a further improvement of the present invention, the main driving assembly includes a main driving wheel disposed in the middle of the main body, a first driven wheel in transmission connection with the main driving wheel, a first meshing gear coaxially connected with the first driven wheel, a second driven wheel disposed on the rear wheel rotating shaft, a first transmission member for transmission connection between the main driving wheel and the first driven wheel, and a second transmission member for transmission connection between the main driving wheel and the second driven wheel, and the pedal is connected to the center of the driving wheel; and the main driving assembly is in transmission connection with the directional transmission assembly through the first meshing gear.

As a further improvement of the present invention, the first transmission member and the second transmission member are both transmission chains, and the main driving wheel, the first driven wheel and the second driven wheel are all provided with gear teeth corresponding to the transmission chains.

As a further improvement of the present invention, the secondary driving assembly includes a secondary driving wheel disposed on the front wheel rotating shaft, a second engaging gear disposed on the main body, and a third transmission member drivingly connecting the secondary driving wheel and the second engaging gear, and the secondary driving assembly is drivingly connected to the directional transmission assembly through the second engaging gear.

As a further improvement of the present invention, the third transmission member is a universal joint transmission system, the universal joint transmission system is formed by combining a steering structure formed by connecting at least 3 universal joints and two connecting gears arranged at two ends of the steering structure, and the two connecting gears are respectively in meshing transmission connection with the auxiliary driving wheel and the second meshing gear.

As a further development of the utility model, the transmission ratio between the main drive assembly and the directional transmission assembly is i 1; the transmission ratio between the secondary drive assembly and the directional transmission assembly is i 2; and i1 ═ i 2.

The utility model has the beneficial effects that: according to the dual-drive bicycle, the directional transmission assembly is arranged, so that the main drive assembly for driving the rear wheel is in transmission connection with the auxiliary drive assembly for driving the front wheel through the directional transmission assembly, meanwhile, the directional transmission assembly can be switched between a transmission state and a separation state, so that the main drive assembly is in transmission connection with the auxiliary drive assembly when the dual-drive bicycle is in straight running, and at the moment, the front wheel and the rear wheel are both driving wheels, so that the riding process is more labor-saving and faster; when the dual-drive bicycle turns, the main drive assembly and the auxiliary drive assembly are separated in transmission, the front wheel is a driven wheel, and the rear wheel is a drive wheel, so that the normal steering of the dual-drive bicycle is ensured, and the problems of skidding, wheel abrasion and the like caused by dual force couple are avoided.

Drawings

FIG. 1 is a schematic structural view of the tandem bicycle of the present invention.

Fig. 2 is an enlarged schematic view of the orientation drive assembly of fig. 1 in position.

FIG. 3 is a schematic view of the third transmission member of FIG. 1.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.

It should be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and/or processing steps closely related to the aspects of the present invention are shown in the drawings, and other details not closely related to the present invention are omitted.

In addition, it is also to be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Referring to fig. 1 to 2, a dual-drive bicycle 100 according to the present invention includes a frame 1, a front wheel 2 connected to a front end of the frame 1, a rear wheel 3 connected to a rear end of the frame 1, a main driving assembly 4 for driving the rear wheel 3 to rotate, and pedals 5 connected to the main driving assembly 4, and the dual-drive bicycle 100 further includes an auxiliary driving assembly 6 connected to the front wheel 2 and a directional transmission assembly 7 connected to the frame 1. In addition, the tandem bicycle 100 further includes conventional accessories included in bicycles of the prior art, such as a seat, a brake device, a rear bracket for carrying a person, a basket, etc., which are not described in detail in this specification since they are mature accessories.

The frame 1 includes a main body 11, a front fork 12 rotatably connected to a front end of the main body 11, a rear fork 13 fixedly connected to a rear end of the main body 11, and a handle 14 for rotating the front fork 12. The front wheel rotation shaft 21 of the front wheel 2 is rotatably connected to an end portion where the front fork 12 extends, and the rear wheel rotation shaft 31 of the rear wheel 3 is connected to an end portion where the rear fork 13 extends.

In a preferred embodiment of the present invention, the main body 11 is disposed in a substantially inverted triangle, and the front fork 12 partially penetrates the main body 11 and is rotatably connected to the main body 11. The handlebar 14 is inserted into the front fork 12, and the front fork 12 can rotate with the rotation of the handlebar 14, and then the front wheel 2 connected to the front fork 12 is driven to rotate. Further, a locking member (not shown) is provided at a position where the front fork 12 is connected to the handlebar 14 to prevent the handlebar 14 from rotating relative to the front fork 12 when the handlebar 14 rotates the front fork 12 and the front wheel 2.

The rear fork 13 is integrally provided with the main body 11, and the rear fork 13 is simultaneously provided with 2 sets to ensure the stability of the rear fork 13 connecting the rear wheel 3.

The main driving assembly 4 includes a main driving wheel 41 disposed at a middle portion of the main body 11, a first driven wheel 42 in transmission connection with the main driving wheel 41, a first meshing gear 43 coaxially connected with the first driven wheel 42, a second driven wheel 44 disposed on the rear wheel rotating shaft 31, a first transmission member 45 for transmission connection between the main driving wheel 41 and the first driven wheel 42, and a second transmission member 46 for transmission connection between the main driving wheel 41 and the second driven wheel 44.

In the present invention, the main driving wheel 41 is disposed at the bottom middle position of the main body 11, and the pedal 5 is disposed at the center position of the main driving wheel 41, so that the main driving wheel 41 is driven to rotate by stepping on the pedal 5; the first driven wheel 42 and the first engaging gear 43 are coaxially disposed and located on a cross beam at an upper portion of the main body 11, further, a bearing bracket (not shown) for bearing the first driven wheel 42 and the first engaging gear 43 is disposed on the cross beam of the main body 11, and the first transmission member 45 is disposed between the main driving wheel 41 and the first driven wheel 42 and is in transmission connection with the main driving wheel 41 and the first driven wheel 42, respectively, so that when the main driving wheel 41 rotates, the first driven wheel 42 and the first engaging gear 43 coaxially disposed with the first driven wheel 42 are driven to rotate by the first transmission member 45.

The second driven wheel 44 is disposed on an extended shaft of the rear wheel rotating shaft 31, and the second transmission member 46 is connected between the second driven wheel 44 and the main driving wheel 41 so that the second driven wheel 44 and the rear wheel 3 disposed coaxially with the second driven wheel 44 are rotated by the second transmission member 46 when the main driving wheel 41 is rotated.

In a preferred embodiment of the present invention, the first transmission member 45 and the second transmission member 46 are transmission chains, and the outer peripheral surfaces of the main driving wheel 41, the first driven wheel 42 and the second driven wheel 44 are all provided with gear teeth corresponding to the transmission chains, and further, the main driving wheel 41 includes two sets of gear teeth with the same number of teeth and the same distance, so that the main driving wheel 41 can simultaneously drive the first transmission member 45 and the second transmission member 46 to move, and then drive the first driven wheel 42 and the second driven wheel 44 to rotate.

The auxiliary driving assembly 6 is in transmission connection with the main driving assembly 4 through the directional transmission assembly 7, and the auxiliary driving assembly 6 comprises an auxiliary driving wheel 61 arranged on the front wheel rotating shaft 21, a second meshing gear 62 arranged on the main body 11 and a third transmission piece 63 in transmission connection with the auxiliary driving wheel 61 and the second meshing gear 62.

Specifically, the auxiliary driving wheel 61 is fixedly connected to an extending shaft of the front wheel rotating shaft 21, so that the front wheel 2 is driven to rotate at the same angular speed by the auxiliary driving wheel 61; the second meshing gear 62 is arranged on a cross beam at the upper part of the main body 11, a bearing member arranged in a staggered manner with the bearing support is arranged on the cross beam of the main body 11, and the second meshing gear 62 is rotatably connected with the bearing member through a bearing, so that the auxiliary driving assembly 6 is in transmission connection with the directional transmission assembly 7 through the second meshing gear 62.

Third driving medium 63 transmission connection is between vice driving wheel 61 and second meshing gear 62, so set up, when main driving wheel 41 rotated, main driving wheel 41's power passed through first driving medium 45 and driven first wheel 42 and the first meshing gear 43 with the coaxial setting of driven first wheel 42 and rotated to through the directional transmission subassembly 7 with second meshing gear 62 meshing connection with will drive power transmission to in the vice driving wheel 61, make front wheel 2 and rear wheel 3 driven simultaneously, then let the process of riding more laborsaving, quick.

Referring to fig. 3 in combination with fig. 2, the third transmission member 63 is a universal joint transmission system, and the universal joint transmission system is formed by connecting a steering structure formed by connecting at least 3 universal joints 631 and a first connecting gear 632 and a second connecting gear 633 which are arranged at two ends of the steering structure. At least three universal joint 631 end to end connection for the combination constitutes turns to the structure and can follow the crossbeam of main part 11, the front end of main part 11 and front fork 12 are buckled and are arranged and carry out the transmission of power, and 3 universal joints 631 are located the corner position department that turns to the structure and turn to, so set up, can effectively promote the degree of freedom of third driving medium 63, realize the power transmission of third driving medium 63 variable angle, in order to avoid front wheel 2 when turning to under handlebar 14 and front fork 12's drive, third driving medium 63 can't carry out effectual power transmission because of taking place deformation.

The first connecting gear 632 is in meshing transmission connection with the auxiliary driving wheel 61, the first connecting gear 632 and the auxiliary driving wheel 61 are bevel gears matched with each other, and when the first connecting gear 632 is meshed with the auxiliary driving wheel 61, a gear shaft of the first connecting gear 632 is perpendicular to a gear shaft of the auxiliary driving wheel 61; the second connecting gear 633 is in meshing transmission connection with the second meshing gear 62, the second connecting gear 633 and the second meshing gear 62 are mutually matched bevel gears, and when the second connecting gear 633 is meshed with the second meshing gear 62, a gear shaft of the second connecting gear 633 is perpendicular to a gear shaft of the second meshing gear 62.

The third transmission member 63 is detachably connected to one side of the main body 11 and the front fork 12 through a clamping structure (not shown), and the second connecting gear 633 is meshed with the second connecting gear 633 from below the second meshing gear 62, so that the mutual interference between the second connecting gear 633 and the directional transmission assembly 7 can be avoided, the combined volume between the secondary driving assembly 6 and the directional transmission assembly 7 can be effectively reduced, and the practicability of the present invention is improved.

It should be noted that, in the description and the drawings of the present invention, only the third transmission member 63 is disposed on the outer side surfaces of the main body 11 and the front fork 12 for illustration, in other embodiments of the present invention, the third transmission member 63 may be further accommodated in the main body 11, the front end of the main body 11 and the hollow tube cavity of the front fork 12, and at this time, the first connecting gear 632 partially penetrates the tube cavity of the front fork 12 to be in meshing transmission connection with the auxiliary driving wheel 61, and the second connecting gear 633 partially penetrates the cross beam of the main body 11 to be in meshing transmission connection with the second meshing gear 62; that is, the position of the third transmission member 63 is only exemplary in the present invention, and should not be limited thereto.

It should be noted that the number of universal joints 631 is related to the structure of the front fork 12, and it is only necessary to ensure that the variable-angle power transmission of the steering structure can be realized by the outer side surfaces of the attachable main body 11 and the front fork 12 or the hollow tube cavities of the main body 11 and the front fork 12 of the steering structure formed by the plurality of universal joints 631, that is, the number of universal joints 631 in the present specification and the drawings is also exemplary and should not be limited thereto.

The directional transmission assembly 7 has a transmission state for controlling the transmission connection between the primary drive assembly 4 and the secondary drive assembly 6 and a disengagement state for controlling the transmission disengagement between the primary drive assembly 4 and the secondary drive assembly 6. The directional transmission assembly 7 includes a transmission member 71 connected to the front fork 12, a crank 72 rotatably connected to the transmission member 71, and a gear transmission 73 connected to the crank 72.

In the present invention, the transmission member 71 is disposed in a plate shape and can move simultaneously with the front fork 12 when the handlebar 14 controls the front fork 12 to rotate, and one end of the crank 72 is rotatably connected to the transmission member 71 through a bearing; the other end is connected with the gear transmission part 73 through a bearing. In this embodiment, the transmission member 71 is disposed in a circular or sector plate shape, and the directional transmission range of the transmission member 71 is within ± 10 °, that is, when the rotation angle of the transmission member 71 is within ± 10 °, the directional transmission assembly 7 is in a transmission state, at this time, the front wheel 2 and the rear wheel 3 are still in a dual-drive state, and the problems of skidding, wheel wear and the like caused by dual force couple can be ignored; when the rotation angle of the transmission member 71 in any direction is greater than 10 °, the directional transmission assembly 7 is in a separated state, and at this time, the front wheel 2 is a driven wheel, and the rear wheel 3 is a driving wheel, so as to avoid the problems of slipping, wheel abrasion and the like caused by double force couple.

It should be noted that the directional transmission range of the transmission member 71 is related to the length ratio between the radius/length of the transmission member 71 and the length of the crank 72, and the directional transmission range in the present invention is only exemplary and should not be limited thereto.

Specifically, the gear transmission portion 73 includes a positioning frame (not shown) disposed on a cross beam of the main body 11, a sliding rod 731 slidably connected to the positioning frame, and two bevel gears 732 disposed on the sliding rod 731, the sliding rod 731 is disposed substantially parallel to the cross beam, one end of the sliding rod 731 is rotatably connected to an extended end of the crank 72, so that when the crank 72 moves along with the rotation of the transmission member 71, the two bevel gears 732 connected to the sliding rod 731 are driven to reciprocate along the extending direction of the sliding rod 731 and the cross beam, so that the directional transmission assembly 7 has a transmission state and a separation state that can be switched back and forth; the two bevel gears 732 are arranged in a staggered manner in the extending direction of the sliding rod 731, and are respectively in meshed connection with the first meshed gear 43 in the main driving component 4 and the second meshed gear 62 in the secondary driving component 6, and the first meshed gear 43 and the second meshed gear 62 are bevel gears having the same size as the two bevel gears 732.

When the tandem bicycle 100 of the present invention is in the straight running state, the transmission member 71 is in the initial position, the crank 72 and the slide bar 731 are in the same straight line and parallel to the cross beam, and at this time, the directional transmission assembly 7 is in the transmission state. The pedal 15 is stepped to drive the main driving wheel 41 to rotate, and the main driving wheel 41 drives the first driven wheel 42 and the first meshing gear 43 coaxially connected with the first driven wheel 42 to rotate through the first transmission piece 45; meanwhile, the main driving wheel 41 drives the second driven wheel 44 and the rear wheel 3 coaxially arranged with the second driven wheel 44 to synchronously rotate through the second transmission piece 46, and the transmission ratio between the main driving wheel 41 and the first driven wheel 42/the first meshing gear 43 and the transmission ratio between the main driving wheel 41 and the second driven wheel 44/the rear wheel 3 are both i 1.

Specifically, the bevel gear 732 near the end where the sliding bar 731 extends is in meshing connection with the first meshing gear 43; and drives the sliding rod 731 and the bevel gear 732 arranged at one side of the sliding rod 731 close to the crank 72 to rotate by taking the central axis of the sliding rod 731 as an axis; the bevel gear 732 on the side close to the crank 72 is meshed with the second meshing gear 62 to drive the second meshing gear 62 to rotate circumferentially, so as to further transmit the power of the main driving wheel 41 to the auxiliary driving wheel 61 through the third transmission member 63 and then drive the front wheel 2 coaxial with the auxiliary driving wheel 61 to rotate, the transmission ratios between the main driving wheel 41 and the second meshing gear 62/the auxiliary driving wheel 61/the front wheel 2 are both i2, and the transmission ratio i1 is equal to the transmission ratio i2, so that the front wheel 2 and the rear wheel 3 are driven simultaneously at the same angular speed, and then the dual-drive bicycle 100 is in a dual-drive state, thereby facilitating riding or accelerating.

When the tandem bicycle 100 of the present invention needs to turn, the directional transmission assembly 7 is in the disengaged state, the transmission member 71 is in the rotational position, the crank 72 is driven by the transmission member 71 to drive the sliding bar 731 to slide along the extending direction of the cross beam, and at this time, the bevel gear 732 is disengaged from the first engaging gear 43 and/or the second engaging gear 62.

At this time, when the pedals 15 are stepped to drive the main driving wheel 41 to rotate, on one hand, the main driving wheel 41 drives the second driven wheel 44 and the rear wheel 3 coaxially arranged with the second driven wheel 44 to synchronously rotate with the main driving wheel 41 through the second transmission piece 46, so that the rear wheel 3 is driven to ensure the normal running of the dual-drive bicycle 100; on the other hand, the first driving member 45 drives the first driven wheel 42 and the first meshing gear 43 coaxially connected with the first driven wheel 42 to rotate, and since the first meshing gear 43 is separated from the bevel gear 732, the power transmission of the main driving wheel 41 is cut off, so that the front wheel 2 is a driven structure incapable of being driven autonomously, thereby avoiding the occurrence of the conditions of abrasion of the tire hub or rollover and the like in the dual-drive bicycle 100, and ensuring the normal steering of the dual-drive bicycle 100.

When the tandem bicycle 100 is returned to the straight running state, the directional transmission assembly 7 is returned to the transmission state, the transmission member 71 returns to the initial position, and the crank 72 and the slide bar 731 rotate to a straight line, so that the bevel gear 732 near the end where the slide bar 731 extends and the first meshing gear 43, and the bevel gear 732 near the crank 72 side and the second meshing gear 62 are meshed again; then, the main driving wheel 41 simultaneously drives the front wheel 2 and the rear wheel 3 to rotate, so that the dual-drive operation of the dual-drive bicycle 100 is realized.

It should be noted that, in the drawings of the present invention, the dual-drive bicycle 100 is only exemplified by a general bicycle which is provided with the main drive assembly 4 for driving the rear wheel 3, the auxiliary drive assembly 6 for driving the front wheel 2, and the directional drive assembly 7 for driving and connecting the main drive assembly 4 and the auxiliary drive assembly 6, and in other embodiments of the present invention, the dual-drive bicycle 100 may also be a common bicycle body structure such as a mountain bike, a road bike, a folding bike, etc. which is provided with the main drive assembly 4, the auxiliary drive assembly 6, and the directional drive assembly 7, that is, the structure of the dual-drive bicycle 100 in the drawings of the present invention is merely exemplary and should not be limited thereto.

In summary, the directional transmission assembly 7 is arranged in the dual-drive bicycle 100, so that the main drive assembly 4 for driving the rear wheel 3 and the auxiliary drive assembly 6 for driving the front wheel 2 are in transmission connection through the directional transmission assembly 7, and meanwhile, the directional transmission assembly 7 can be switched between a transmission state and a separation state, so that the main drive assembly 4 and the auxiliary drive assembly 6 are in transmission connection when the dual-drive bicycle 100 is in straight running, and at the moment, the front wheel 2 and the rear wheel 3 are both driving wheels, so that the riding process is more labor-saving and faster; when the dual-drive bicycle 100 turns, the main drive component 4 and the auxiliary drive component 6 are separated in a transmission manner, the front wheel 2 is a driven wheel, and the rear wheel 3 is a drive wheel, so that the normal steering of the dual-drive bicycle 100 is ensured, and the problems of slipping, wheel abrasion and the like caused by dual-force couple are avoided.

Although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the spirit and scope of the present invention.

Claims

1. The utility model provides a dual drive bicycle, includes the frame, connects the front wheel of frame front end and connection are in the rear wheel of frame rear end, be used for driving the main drive subassembly that the rear wheel rotated and connect pedal on the main drive subassembly, its characterized in that: the front wheel steering device further comprises an auxiliary driving assembly connected to the front wheel and a directional transmission assembly connected to the frame, the auxiliary driving assembly is in driving connection with the main driving assembly through the directional transmission assembly, and the directional transmission assembly can be switched between a transmission state and a separation state to control the main driving assembly and the auxiliary driving assembly to be in transmission connection or transmission separation.

2. A tandem bicycle according to claim 1, wherein: the frame comprises a main body, a front fork rotatably connected to the front end of the main body, a rear fork fixedly connected to the rear end of the main body, and a handlebar for driving the front fork to rotate, wherein a front wheel rotating shaft of the front wheel is rotatably connected to the end part of the front fork in extension, and a rear wheel rotating shaft of the rear wheel is rotatably connected to the end part of the rear fork in extension.

3. A tandem bicycle according to claim 2, wherein: the directional transmission assembly comprises a transmission component connected to the front fork, a crank rotatably connected to the transmission component and a gear transmission part connected with the crank.

4. A tandem bicycle according to claim 3, wherein: the gear transmission part comprises a positioning frame arranged on the main body, a sliding rod connected on the positioning frame in a sliding mode and two bevel gears arranged on the sliding rod, wherein the bevel gears are arranged in a staggered mode in the front and back direction of the extending direction of the sliding rod and are respectively meshed with the main driving assembly and the auxiliary driving assembly.

5. A tandem bicycle according to claim 4, wherein: the transmission member is arranged in a plate shape and can move simultaneously with the front fork when the handlebar controls the front fork to rotate, and one end of the crank is rotatably connected to the transmission member through a bearing; the other end of the driving mechanism is connected with the sliding rod through a bearing so as to drive the two conical gears arranged on the sliding rod to be separated from or connected with the main driving assembly and/or the auxiliary driving assembly.

6. A tandem bicycle according to claim 4, wherein: the main driving assembly comprises a main driving wheel arranged in the middle of the main body, a first driven wheel in transmission connection with the main driving wheel, a first meshing gear coaxially connected with the first driven wheel, a second driven wheel arranged on the rear wheel rotating shaft, a first transmission piece used for being in transmission connection with the main driving wheel and the first driven wheel, and a second transmission piece used for being in transmission connection with the main driving wheel and the second driven wheel, and the pedal is connected to the center of the main driving wheel; and the main driving assembly is in transmission connection with the directional transmission assembly through the first meshing gear.

7. A tandem bicycle according to claim 6, wherein: the first transmission piece and the second transmission piece are both transmission chains, and the main driving wheel, the first driven wheel and the second driven wheel are all provided with gear teeth which correspond to the transmission chains.

8. A tandem bicycle according to claim 2, wherein: the auxiliary driving assembly comprises an auxiliary driving wheel arranged on the front wheel rotating shaft, a second meshing gear arranged on the main body and a third transmission piece in transmission connection with the auxiliary driving wheel and the second meshing gear, and the auxiliary driving assembly is in transmission connection with the directional transmission assembly through the second meshing gear.

9. A tandem bicycle according to claim 8, wherein: the third driving medium is a universal joint transmission system, the universal joint transmission system is composed of a steering structure formed by connecting at least 3 universal joints and two connecting gears arranged at two ends of the steering structure, and the two connecting gears are respectively in meshing transmission connection with the auxiliary driving wheel and the second meshing gear.

10. A tandem bicycle according to claim 1, wherein: the transmission ratio between the main drive assembly and the directional transmission assembly is i 1; the transmission ratio between the secondary drive assembly and the directional transmission assembly is i 2; and i1 ═ i 2.