Family Bicycle

Abstract

The present invention discloses a parent-child bicycle, which belongs to the technical field of bicycles and is designed to solve the problem that the existing tandem bicycle cannot drive the front wheel and the rear wheel separately. The parent-child bicycle of the present invention comprises a frame body composed of a front frame assembly and a rear frame assembly, the front frame assembly also comprises a front transmission structure, the front transmission structure is configured to transmit the rotation of the front pedal shaft to the front wheel to drive the front wheel to rotate; the rear frame assembly comprises a rear transmission structure, the rear transmission structure is configured to transmit the rotation of the rear pedal shaft to the rear wheel to drive the rear wheel to rotate. When the parent-child bicycle of the present invention is ridden by the parent and the child together, the child steps on the pedal installed on the front pedal shaft, and the power is transmitted to the front wheel; the parent steps on the pedal installed on the rear pedal shaft, and the power is transmitted to the rear wheel, the parent and the child can work together without interfering with each other, so that the child can get better exercise.

Description

Technical Field

[0001] The invention relates to the technical field of bicycles, and in particular to a parent-child bicycle. Background Art

[0002] With the gradual improvement of educational concepts, raising children is no longer just about providing them with material security, but more about accompanying them. Outings, physical exercise, etc. are good parent-child activities that can enhance the intimacy between parents and children.

[0003] Existing tandem bicycles are generally designed for adults, and their design focuses on saving riding effort or folding for storage to save storage space. The use needs when one of the riders is a child are not considered, resulting in the existing tandem bicycles being difficult to use as a means of transportation for parent-child travel.

[0004] Specifically, the two riders of the existing tandem bicycle combine their pedaling forces to drive the bicycle together. When a parent and a child ride together, the child's strength is obviously less than that of the parent. The final result is equivalent to the parent riding the bicycle by himself, without giving the child enough exercise. The steering of the existing tandem bicycle is controlled by the rider sitting in the front seat. When a parent and a child ride together, the child basically sits in the front seat for safety. If the child controls the steering and the parent cannot control the riding direction, the riding safety cannot be guaranteed. Summary of the invention

[0005] The purpose of the present invention is to provide a parent-child bicycle, in which the child and the parent can drive the front wheel and the rear wheel to rotate respectively, providing more exercise opportunities for the child, and the parent can monitor the child in real time and control the direction to ensure riding safety.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] A parent-child bicycle comprises a frame body consisting of a front frame assembly and a rear frame assembly, wherein the front frame assembly comprises a front vehicle frame, a front handrail, a front wheel, a front pedal shaft and a front vehicle seat, and the rear vehicle frame assembly comprises a rear vehicle frame, a rear handrail, a rear wheel, a rear pedal shaft and a rear vehicle seat, wherein the front frame assembly also comprises a front transmission structure, wherein the front transmission structure is configured to transmit the rotation of the front pedal shaft to the front wheel so as to drive the front wheel to rotate; and the rear frame assembly comprises a rear transmission structure, wherein the rear transmission structure is configured to transmit the rotation of the rear pedal shaft to the rear wheel so as to drive the rear wheel to rotate.

[0008] In particular, the front transmission structure and the rear transmission structure are respectively gear meshing transmission parts or chain sprocket transmission parts.

[0009] In particular, the front transmission structure includes a pedal shaft bevel gear arranged on the front pedal shaft, a primary rotating rod pedal end bevel gear meshing with the pedal shaft bevel gear, a primary rotating rod handrail end bevel gear connected to the primary rotating rod pedal end bevel gear through a primary rotating rod, a steering shaft bevel gear meshing with the primary rotating rod handrail end bevel gear, a steering shaft spur gear coaxially arranged with the steering shaft bevel gear, a secondary rotating rod spur gear meshing with the steering shaft spur gear, a secondary rotating rod bevel gear connected to the secondary rotating rod spur gear through a secondary rotating rod, and a front wheel shaft bevel gear meshing with the secondary rotating rod bevel gear, the front wheel shaft bevel gear is sleeved on the front wheel shaft assembly, and the steering shaft bevel gear and the steering shaft spur gear are sleeved on the steering shaft.

[0010] In particular, the rear transmission structure includes a rear pedal shaft bevel gear arranged on the rear pedal shaft, a rear drive rotating rod pedal end bevel gear meshing with the rear pedal shaft bevel gear, a rear drive rotating rod wheel end bevel gear connected to the rear drive rotating rod pedal end bevel gear through the rear drive rotating rod, and a rear wheel axle bevel gear meshing with the rear drive rotating rod wheel end bevel gear, and the rear wheel axle bevel gear is arranged on the rear wheel axle assembly.

[0011] In particular, a rear steering shaft is arranged in the rear armrest support tube of the rear armrest, a rear steering gear is sleeved on the rear steering shaft, the rear steering gear is meshed with the steering transition gear, the steering transition gear is meshed with the front steering gear, two steering steel ropes are sleeved on the front steering gear, one end of the steering steel rope away from the front steering gear is connected to the steering shaft, and the steering shaft is passed through the front armrest support tube of the front armrest.

[0012] In particular, a folding mechanism is provided at the connection between the front side frame assembly and the rear side frame assembly, and the folding mechanism includes a hollow folding body, a folding cover plate hinged to the folding body, and a folding hinge shaft hinged to the folding body and the folding cover plate together, the folding body is connected to one of the front side vehicle frame and the rear side vehicle frame, and the folding cover plate is connected to the other of the two; the steering transition gear is arranged in the folding body, a folding body through hole is opened on the folding body, and the steering transition gear is meshed with the rear steering gear or the front steering gear through the folding body through hole.

[0013] In particular, the front armrest is provided with a socket for inserting a steering key, and a hollow plate is provided on the steering shaft, and a locking hole and a free rotation hole are formed on the hollow plate; when the steering key is inserted into the locking hole, the front armrest and the steering shaft can rotate synchronously, and when the steering key is inserted into the free rotation hole, the front armrest can rotate freely relative to the steering shaft.

[0014] In particular, the steering key includes a columnar key rod body, a hand-held portion arranged at the top end of the key rod body, and a protrusion arranged at the bottom end of the key rod body, and the protrusion is eccentrically arranged relative to the key rod body; the shape of the locking hole is the same as the cross-section of the protrusion, and the free rotation hole can allow the protrusion to rotate freely at a set angle therein.

[0015] In particular, the frame body includes a detachable front frame assembly and two rear frame assemblies, the two rear frame assemblies are connected by a connecting crossbeam, and the two rear frame assemblies connected as a whole are connected to the front frame assembly by a herringbone beam.

[0016] In particular, a rear steering shaft is arranged in the rear armrest support tube of one of the two rear frame assemblies, a side steering gear is sleeved on the rear steering shaft, the side steering gear is connected to the rear steering gear through a side steering steel rope, the rear steering gear is meshed with the steering transition gear, the steering transition gear is meshed with the front steering gear, two steering steel ropes are sleeved on the front steering gear, one end of the steering steel rope away from the front steering gear is connected to the steering shaft, and the steering shaft is passed through the front armrest support tube of the front armrest.

[0017] The parent-child bicycle of the present invention comprises a front transmission structure capable of transmitting the rotation of a front pedal shaft to a front wheel to drive the front wheel to rotate, and a rear transmission structure for transmitting the rotation of a rear pedal shaft to the rear wheel to drive the rear wheel to rotate. When the parent and the child ride together, the child steps on a pedal installed on the front pedal shaft, and power is transmitted to the front wheel; the parent steps on a pedal installed on the rear pedal shaft, and power is transmitted to the rear wheel. The parent and the child can work together without interfering with each other, so that the child can get better exercise and enhance the close relationship between the parent and the child; the bicycle can also be formed into a three-wheeled bicycle for three people to ride together for a family of three; the parent-child bicycle is foldable, and its volume is small after folding, so that it can be transported in long-distance transportation tools such as cars; the child sits in the front, which is convenient for the parent to observe the child's behavior and ensure the child's safety, and the parent sitting in the back controls the steering of the bicycle, so that riding is safer; according to the use requirements, the child can also control the steering through the front handrail, and the use mode is flexible and diverse, and the switching between the use modes is convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a two-person two-wheel parent-child bicycle provided by a specific embodiment of the present invention;

[0019] Figure 2 It is a schematic diagram of a front transmission structure and a rear control steering structure provided in a specific embodiment of the present invention;

[0020] Figure 3 is a schematic diagram of a rear transmission structure provided in a specific embodiment of the present invention;

[0021] Figure 4 is an exploded view of a folding mechanism provided in a specific embodiment of the present invention;

[0022] Figure 5 is a schematic structural diagram of a steering key provided in a specific embodiment of the present invention;

[0023] Figure 6 It is a structural schematic diagram of a steering shaft and a front armrest support tube provided in a specific embodiment of the present invention;

[0024] Figure 7 is a top view of a steering shaft provided in a specific embodiment of the present invention;

[0025] Figure 8 It is a structural schematic diagram of another two-person two-wheel parent-child bicycle provided by a specific embodiment of the present invention;

[0026] Fig. 9 yes Figure 8 The schematic diagram of the structure of the rear control steering of the two-person two-wheel parent-child bicycle shown;

[0027] Fig.10 It is a structural schematic diagram of a three-person three-wheel parent-child bicycle provided by a specific embodiment of the present invention;

[0028] Fig.11 It is a structural schematic diagram of a herringbone beam provided in a specific embodiment of the present invention;

[0029] Fig.12 The present invention is a schematic diagram of the structure of rear control steering of a three-wheeled parent-child bicycle for three persons provided in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0031] This embodiment discloses a parent-child bicycle, such as Figures 1 to 12As shown, the parent-child bicycle includes a frame body composed of a front frame assembly and a rear frame assembly. The front frame assembly includes a front frame 11, a front handrail 12, a front wheel 13, a front pedal shaft 14 and a front seat 15, and the rear frame assembly includes a rear frame 21, a rear handrail 22, a rear wheel 23, a rear pedal shaft 24 and a rear seat 25. The front seat 15 is set shorter or height-adjustable to adapt to the height of children; the front pedal shaft 14 on the front frame 11 can be arranged closer to the front seat 15, so that children whose legs are not long enough can ride easily. Soft cable brake mechanisms can be installed on both the front and rear wheels.

[0032] The front frame assembly also includes a front transmission structure, which is configured to transmit the rotation of the front pedal shaft 14 to the front wheel 13 to drive the front wheel 13 to rotate; the rear frame assembly includes a rear transmission structure, which is configured to transmit the rotation of the rear pedal shaft 24 to the rear wheel 23 to drive the rear wheel 23 to rotate.

[0033] When parents and children ride together, the child steps on the pedal installed on the front pedal shaft 14, and the power is transmitted to the front wheel; the parent steps on the pedal installed on the rear pedal shaft 24, and the power is transmitted to the rear wheel. The parent and the child can work together without interfering with each other, so that the child can get better exercise and enhance the intimacy between the parent and the child.

[0034] In order to prevent the front and rear wheels from rotating at different speeds, which may cause the speed of the front pedal shaft 14 to exceed the speed at which the child actively steps on the pedal, a flywheel or other unidirectionally rotatable structure may be installed on the front wheel shaft assembly 17. When the child steps on the pedal, the power is transmitted to the front wheel shaft assembly 17, and the front wheel 13 rotates normally. When the parent steps on the pedal at a faster speed, the rear wheel 23 rotates rapidly, causing the front wheel 13 to rotate rapidly as well. At this time, the unidirectional rotation structure comes into play, and the rapidly rotating front wheel 13 does not reversely transmit the power to the front pedal shaft 14 through the front transmission structure, thereby ensuring the safety of the child.

[0035] The specific devices of the front transmission structure and the rear transmission structure are not limited, as long as they can achieve power transmission. Preferably, the front transmission structure and the rear transmission structure are respectively gear meshing transmission parts or chain sprocket transmission parts, which have low cost, stable use status and mature technology.

[0036] In this embodiment, the front transmission structure and the rear transmission structure are both gear meshing transmission components. Figure 1 and Figure 2As shown, the front transmission structure includes a pedal shaft bevel gear 161 disposed on the front pedal shaft 14, a primary rotating rod pedal end bevel gear 162 meshing with the pedal shaft bevel gear 161, a primary rotating rod handrail end bevel gear 164 connected to the primary rotating rod pedal end bevel gear 162 through a primary rotating rod 163, a steering shaft bevel gear 165 meshing with the primary rotating rod handrail end bevel gear 164, a steering shaft spur gear 166 coaxially disposed with the steering shaft bevel gear 165, a secondary rotating rod spur gear 167 meshing with the steering shaft spur gear 166, a secondary rotating rod bevel gear 169 connected to the secondary rotating rod spur gear 167 through a secondary rotating rod 168, and a front wheel shaft bevel gear 170 meshing with the secondary rotating rod bevel gear 169. The front wheel shaft bevel gear 170 is sleeved on the front wheel shaft assembly 17, and the steering shaft bevel gear 165 and the steering shaft spur gear 166 are sleeved on the steering shaft 18.

[0037] The pedal shaft bevel gear 161 and the primary rotating rod pedal end bevel gear 162 form a first set of gear meshing structures to change the direction of the rotation on the front pedal shaft 14; the rotation is transmitted to the front gearbox 19 through the primary rotating rod 163, and the primary rotating rod handrail end bevel gear 164 and the steering shaft bevel gear 165 located in the front gearbox 19 form a second set of gear meshing structures. The second set of bevel gear meshing structures changes the direction of the rotation again, becoming a rotation motion that passes vertically through the center of the front wheel 13 and is in the same plane as the front wheel 13; the steering The shaft spur gear 166 and the secondary rotating rod spur gear 167 form a third set of gear meshing structure, which transmits the rotational power to the front fork 10 on one side. The secondary rotating rod 168 is arranged in the front fork 10. The secondary rotating rod 168 transmits the power to the fourth set of gear meshing structure composed of the secondary rotating rod bevel gear 169 and the front wheel shaft bevel gear 170. The fourth set of gear meshing structure changes the direction of rotation again. The front wheel shaft bevel gear 170 drives the flywheel installed on the side of the front wheel. The flywheel with a one-way drive function drives the front wheel 13 to roll forward.

[0038] By changing the rotation direction through the four-group gear meshing structure, the power transmission is smoother, and a gear in the second group of bevel gear meshing structure and a gear in the third group of gear meshing structure are installed on the steering shaft 18. When the front wheel 13 is controlled by the parent from the rear, the driving force for the child's riding will not be interrupted, which is more convenient to use.

[0039] The specific structure for realizing the function of parents controlling the steering from the rear is not limited. Preferably, a rear steering shaft 28 is provided in the rear armrest support tube 221 of the rear armrest 22, and a rear steering gear 31 is sleeved on the rear steering shaft 28. The rear steering gear 31 is meshed with a steering transition gear 32, and the steering transition gear 32 is meshed with a front steering gear 33. Two steering steel ropes 34 are sleeved on the front steering gear 33, and one end of the steering steel rope 34 away from the front steering gear 33 is connected to the steering shaft 18, and the steering shaft 18 is inserted into the front armrest support tube 121 of the front armrest 12. The two steering steel ropes 34 are respectively located on the left and right sides of the axis of the steering shaft 18. When the rear armrest 22 rotates to the left or right, the steering steel rope 34 on the left or right side can be pulled by the rear steering gear 31, the steering transition gear 32 and the front steering gear 33, so that the steering shaft 18 rotates to the left or right.

[0040] The gears and the steering rope 34 and other structures are all built-in, with a more beautiful appearance, and can prevent external forces from hooking or damaging the above structures, making it safer to use.

[0041] Of course, other structures that can realize the function of parents controlling the steering from the back are also possible. For example, two soft ropes are used as steering steel ropes, and the two ends of one soft rope are respectively connected to the left side of the rear handrail 22 and the left side of the steering shaft 18, and the two ends of the other soft rope are respectively connected to the right side of the rear handrail 22 and the right side of the steering shaft 18. When the parent turns the rear handrail 22 to the left or right, the steering shaft 18 will turn to the left or right under the action of the corresponding side soft rope to achieve steering. The end of the soft rope can also be set with a spring to adjust the tightness, which is more labor-saving when used.

[0042] like Figure 3 As shown, the rear transmission structure includes a rear pedal shaft bevel gear 261 arranged on the rear pedal shaft 24, a rear drive rotating rod pedal end bevel gear 262 meshing with the rear pedal shaft bevel gear 261, a rear drive rotating rod wheel end bevel gear 264 connected to the rear drive rotating rod pedal end bevel gear 262 through a rear drive rotating rod 263, and a rear axle bevel gear 265 meshing with the rear drive rotating rod wheel end bevel gear 264, and the rear axle bevel gear 265 is arranged on the rear wheel axle assembly 27.

[0043] The rear pedal shaft bevel gear 261 and the rear drive rotating rod pedal end bevel gear 262 form a fifth gear meshing structure to change the direction of the rotation on the rear pedal shaft 24; the rear drive rotating rod 263 transmits the changed rotation to the sixth gear meshing structure composed of the rear drive rotating rod wheel end bevel gear 264 and the rear wheel shaft bevel gear 265, which changes the direction of the rotation again and then drives the flywheel installed on the side of the rear wheel. The flywheel with a one-way drive function drives the rear wheel 23 to roll forward.

[0044] In order to save storage space, a folding mechanism is provided at the connection between the front frame assembly and the rear frame assembly. Figure 1 and Figure 4 As shown, the folding mechanism includes a hollow folding body 41, a folding cover plate 42 hinged to the folding body 41, and a folding hinge shaft 43 hingedly connecting the folding body 41 and the folding cover plate 42. The folding body 41 is connected to one of the front side vehicle frame 11 and the rear side vehicle frame 21, and the folding cover plate 42 is connected to the other of the two. The folding cover plate 42 and the folding body 41 can rotate smoothly around the folding hinge shaft 43.

[0045] In this embodiment, the folding body 41 is connected to the rear vehicle frame 21, and the folding cover plate 42 is connected to the front vehicle frame 11. The steering transition gear 32 and the rear steering gear 31 are arranged in the folding body 41, and the front steering gear 33 is arranged in the tube body of the front vehicle frame 11. The folding body through hole 411 is provided on the folding body 41, and the steering transition gear 32 is meshed with the front steering gear 33 through the folding body through hole 411. After using this folding method, the steering device will not be damaged during folding, and the operation is convenient, time-saving and labor-saving, and easy to carry and store; when assembling, you only need to pay a little attention to the meshing of the gears and lock the folding cover plate 42 and the folding body 41, and the normal operation of the steering mechanism can be ensured without complicated operations.

[0046] It is not necessary for parents to control the steering from the back instead of letting the child control the steering from the front for safety reasons. When the child has good judgment and direction control ability, the child can control the steering mechanism or the parent and child can control the steering mechanism together.

[0047] To achieve this goal, Figure 1 ,like Figures 5 to 7 As shown, a socket for inserting the steering key 5 is provided on the front armrest 12. When the steering key 5 is inserted into the socket along a first direction, the front armrest 12 and the steering shaft 18 can rotate synchronously. When the steering key 5 is inserted into the socket along a second direction, the front armrest 12 can rotate freely (idle) relative to the steering shaft 18.

[0048] The specific shape of the steering key 5 is not limited. Preferably, the steering key 5 includes a columnar key rod body 51, a hand-held portion 52 arranged at the top of the key rod body 51, and a protrusion 53 arranged at the bottom end of the key rod body 51, and the protrusion 53 is eccentrically arranged relative to the key rod body 51; a hollow plate 181 is arranged on the steering shaft 18, and a locking hole 182 and a free rotation hole 183 are formed on the hollow plate 181. The shape of the locking hole 182 is the same as the cross-section of the protrusion 53, and the free rotation hole 183 can allow the protrusion 53 to rotate freely at a set angle therein.

[0049] Another method is for parents to control the steering from behind, such as Figure 8 and Fig. 9 As shown, the rear frame assembly includes a rear wheel frame shaft 29 that can rotate around its own axis, and the rear wheel frame shaft 29 is connected to the rear frame 21. The rear wheel 23 is installed on the rear wheel frame shaft 29 through some frame structures and can rotate synchronously with the rear wheel frame shaft 29. The gear transmission assembly with the same transmission structure as the front side is installed on the rear frame assembly. When the parent steps on the rear pedal shaft 24, the rear wheel 23 is driven to rotate through the gear transmission assembly, and the child rides forward normally; when the parent rotates the rear handrail 22, the steel rope (not shown) set in the rear frame 21 pulls the rear wheel frame shaft 29 to twist around the axis (refer to the action process of the steering steel rope 34 and the steering shaft 18 of the front frame assembly), so that a certain angle is formed between the plane where the rear wheel 23 is located and the forward direction. Similar to the working principle of the front transmission structure, the gear transmission assembly of the rear frame assembly ensures that the torsion of the rear wheel 23 does not affect the normal riding of the parent, while the torsion of the rear wheel 23 changes the forward direction of the bicycle being ridden, allowing the parent to control the riding direction from the rear.

[0050] Figure 1 The parent-child bicycle shown in the figure is a two-wheeled structure for two people to ride at the same time. Considering the needs of a family of three, it can also be Fig.10 As shown, the frame body includes a detachable front frame assembly and two rear frame assemblies, forming a three-person three-wheel parent-child bicycle. The two rear frame assemblies are connected by a connecting crossbeam 61, and the two rear frame assemblies connected as a whole are connected to the front frame assembly by a herringbone beam 62. The structure and working principle of the two rear frame assemblies are the same as those of the rear frame assembly in the two-person two-wheel parent-child bicycle.

[0051] like Fig.11 As shown, the herringbone beam 62 includes two rear buckles 621 and a front buckle 622, the rear buckle 621 is clamped on the connecting crossbeam 61, and the front buckle 622 is clamped on the front vehicle frame 11. When the three-wheeled vehicle needs to be converted into a two-wheeled vehicle, the connecting crossbeam 61 and the herringbone beam 62 are removed, and the rear vehicle frame 21 is connected to the folding mechanism, which is convenient for disassembly and assembly.

[0052] Fig.12 The figure shows a rear steering control scheme for a three-person three-wheel parent-child bicycle. A rear steering shaft 28 is provided in a rear handrail support tube 221 of one of the two rear frame assemblies. A side steering gear 35 is sleeved on the rear steering shaft 28. The side steering gear 35 is connected to the rear steering gear 31 through a side steering steel rope 36. The rest of the parts are the same as the rear steering control scheme for a two-person two-wheel parent-child bicycle, and will not be described in detail here.

[0053] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A parent-child bicycle, comprising a frame body consisting of a front frame assembly and a rear frame assembly, wherein the front frame assembly comprises a front frame (11), a front handrail (12), a front wheel (13), a front pedal shaft (14) and a front seat (15), and the rear frame assembly comprises a rear frame (21), a rear handrail (22), a rear wheel (23), a rear pedal shaft (24) and a rear seat (25), characterized in that: The front frame assembly further comprises a front transmission structure, wherein the front transmission structure is configured to transmit the rotation of the front pedal shaft (14) to the front wheel (13) so as to drive the front wheel (13) to rotate; the rear frame assembly comprises a rear transmission structure, wherein the rear transmission structure is configured to transmit the rotation of the rear pedal shaft (24) to the rear wheel (23) so as to drive the rear wheel (23) to rotate; The front transmission structure and the rear transmission structure are respectively gear meshing transmission parts or chain sprocket transmission parts; The front transmission structure comprises a pedal shaft bevel gear (161) arranged on the front pedal shaft (14), a primary rotating rod pedal end bevel gear (162) meshing with the pedal shaft bevel gear (161), a primary rotating rod handrail end bevel gear (164) connected to the primary rotating rod pedal end bevel gear (162) via a primary rotating rod (163), a steering shaft bevel gear (165) meshing with the primary rotating rod handrail end bevel gear (164), and a steering shaft spur gear coaxially arranged with the steering shaft bevel gear (165). (166), a secondary rotating rod spur gear (167) meshing with the steering shaft spur gear (166), a secondary rotating rod bevel gear (169) connected to the secondary rotating rod spur gear (167) via a secondary rotating rod (168), and a front wheel shaft bevel gear (170) meshing with the secondary rotating rod bevel gear (169), wherein the front wheel shaft bevel gear (170) is sleeved on the front wheel shaft assembly (17), and the steering shaft bevel gear (165) and the steering shaft spur gear (166) are sleeved on the steering shaft (18); A rear steering shaft (28) is arranged in a rear armrest support tube (221) of the rear armrest (22); a rear steering gear (31) is sleeved on the rear steering shaft (28); the rear steering gear (31) is meshed with a steering transition gear (32); the steering transition gear (32) is meshed with a front steering gear (33); two steering steel ropes (34) are sleeved on the front steering gear (33); one end of the steering steel rope (34) away from the front steering gear (33) is connected to a steering shaft (18); and the steering shaft (18) is inserted into the front armrest support tube (121) of the front armrest (12); A folding mechanism is provided at the connection between the front vehicle frame assembly and the rear vehicle frame assembly, the folding mechanism comprising a hollow folding body (41), a folding cover plate (42) hinged to the folding body (41), and a folding hinge shaft (43) hingedly connecting the folding body (41) and the folding cover plate (42) together, the folding body (41) being connected to one of the front vehicle frame (11) and the rear vehicle frame (21), and the folding cover plate (42) being connected to the other of the two; the steering transition gear (32) is provided in the folding body (41), a folding body through hole (411) is provided on the folding body (41), and the steering transition gear (32) is meshed with the rear steering gear (31) or the front steering gear (33) through the folding body through hole (411).

2. The parent-child bicycle according to claim 1, characterized in that: The rear transmission structure comprises a rear pedal shaft bevel gear (261) arranged on the rear pedal shaft (24), a rear drive rotating rod pedal end bevel gear (262) meshing with the rear pedal shaft bevel gear (261), a rear drive rotating rod wheel end bevel gear (264) connected to the rear drive rotating rod pedal end bevel gear (262) via a rear drive rotating rod (263), and a rear wheel shaft bevel gear (265) meshing with the rear drive rotating rod wheel end bevel gear (264), wherein the rear wheel shaft bevel gear (265) is arranged on the rear wheel shaft assembly (27).

3. The parent-child bicycle according to claim 1, characterized in that: The front armrest (12) is provided with a socket for inserting a steering key (5), and the steering shaft (18) is provided with a hollow plate (181), and the hollow plate (181) is formed with a locking hole (182) and a free rotation hole (183); when the steering key (5) is in the locking hole (182), the front armrest (12) and the steering shaft (18) can rotate synchronously, and when the steering key (5) is in the free rotation hole (183), the front armrest (12) can rotate freely relative to the steering shaft (18).

4. The parent-child bicycle according to claim 3, characterized in that: The steering key (5) comprises a columnar key rod body (51), a grip portion (52) arranged at the top end of the key rod body (51), and a protrusion (53) arranged at the bottom end of the key rod body (51), wherein the protrusion (53) is eccentrically arranged relative to the key rod body (51); the shape of the locking hole (182) is the same as the cross-section of the protrusion (53), and the free rotation hole (183) can allow the protrusion (53) to freely rotate at a set angle therein.

5. The parent-child bicycle according to any one of claims 1 to 2, characterized in that: The frame body comprises a detachably arranged front frame assembly and two rear frame assemblies, the two rear frame assemblies being connected via a connecting crossbeam (61), and the two rear frame assemblies being connected as a whole are connected to the front frame assembly via a herringbone beam (62).

6. The parent-child bicycle according to claim 5, characterized in that: A rear steering shaft (28) is arranged in a rear handrail support tube (221) of one of the two rear frame assemblies, a side steering gear (35) is sleeved on the rear steering shaft (28), and the side steering gear (35) is connected to the rear steering gear (31) via a side steering steel rope (36).

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