JP2013086776A - Bicycle having suspension - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a front suspension and a rear suspension by a simple structure.SOLUTION: This bicycle includes: front and rear wheels 1; a seat tube 9; a head tube 11 with a front fork 10 connected; a crank bearing 15; an elastic frame 30 having a front end fixed to the head tube 11, a rear end fixed to the axle 1b of the rear wheel 1B, and an intermediate part fixed to the seat tube 9; a front under frame 6 having a rear end connected to the crank bearing 15 and a front end fixed to the head tube 11; and a rear under frame 8 having a rear end connected to the axle 1b of the rear wheel 1B and a front end connected to the crank bearing 15. The elastic frame 30 is provided with two elastic rods 30A, and the two elastic rods 30A are arranged at both sides of the seat tube 9 and have intermediate portions fixed to the seat tube 9. In the bicycle, the seat tube 9 is connected to a vertical frame 29 fixed to the crank bearing 15 so as to be vertically moved.

Description

  The present invention relates to a bicycle having a suspension, and more particularly to a bicycle that realizes a suspension by elastically deforming a frame itself.

Bicycles with suspensions have been developed. (See Patent Documents 1 to 3)
As shown in FIG. 1, the bicycle described in Patent Document 1 includes a front suspension 103 that includes a front fork 110 that can be vertically expanded and contracted, and an underframe 106 that is elastically deformed is fixed to a head tube 111. A rear wheel 101 is connected to the rear end.

JP 2004-330866 A Japanese Patent No. 2635442 Japanese Patent No. 3018289

  The bicycle of FIG. 1 can realize the rear suspension 104 by elastically deforming the under frame 106. However, since the front suspension cannot be realized by the elasticity of the frame, it is necessary to have a complicated structure in which the front fork can be expanded and contracted in the vertical direction. The front fork that can be expanded and contracted vertically has a structure that can be expanded and contracted by putting a rod in and out of the cylinder, and further has a structure that can elastically expand and contract by incorporating a coil spring. In the front fork having this structure, the frictional resistance between the cylinder and the rod hinders smooth vertical movement. In order to realize a comfortable suspension that moves smoothly up and down by reducing the frictional resistance, extremely high machining accuracy is required for the cylinder and the rod, and the manufacturing cost increases. Further, the front fork is provided with a caster angle (α) in order to improve the straight traveling performance of the bicycle. This also causes a smooth vertical movement of the front fork. This is because when the front fork is inclined, the surface pressure between the cylinder and the rod increases, and the frictional resistance increases in proportion to the surface pressure. For this reason, the shock absorbing function that efficiently absorbs even minute vibrations is improved to realize a comfortable riding comfort, but there is a very difficult drawback.

  Furthermore, since the rear suspension is realized by the elasticity of a considerably long underframe extending from the head tube to the rear wheel, there is a drawback that it is difficult to prevent lateral deformation and twist of the rear wheel. Ideally, the rear suspension moves smoothly up and down, does not move left and right, and does not twist, but it is difficult to reduce lateral displacement and twist in a long underframe. In particular, it is extremely difficult to prevent lateral displacement and twisting with a single underframe. Furthermore, if the long underframe is deformed in the lateral direction, it will come into contact with the seat tube and smooth vertical movement cannot be realized. In addition, the long underframe twist also has the disadvantage that the rear wheels tilt from a vertical position when accelerating by stepping on the petal with a strong force.

  Further, the bicycles described in Patent Documents 2 and 3 realize a saddle suspension by connecting the front end of an arm, which has a saddle fixed to the rear end, to a head tube so that it can tilt. This bicycle implements a saddle cushion by tilting the tilting arm. In this structure, one end of the arm is connected to the head tube and the saddle is fixed to the rear end. Therefore, it is difficult to firmly connect the arm to the frame, and the saddle is liable to be displaced laterally. Further, since the saddle with heavy weight is supported by the head tube, an extremely strong connection strength is required for the connection portion between the arm and the head tube.

The present invention has been developed for the purpose of solving this drawback. An important object of the present invention is to realize a saddle suspension with an extremely simple structure, and if necessary, to realize a front suspension or a rear suspension with an elastic body that realizes a saddle suspension. The object is to provide a bicycle having a suspension that can be used.
Another important object of the present invention is a suspension that can balance and support the load of the saddle on the head tube and the rear wheel, and can realize a comfortable ride while reducing the lateral displacement and twist of the saddle. It is to provide a bicycle having
Furthermore, another important object of the present invention is to provide a bicycle having a suspension capable of realizing a comfortable riding comfort by absorbing the impact of the upper and lower sides of the saddle with the frame.

Means for Solving the Problems and Effects of the Invention

  In the bicycle having the suspension of the present invention, the front and rear wheels 1, the seat tube 9 having the saddle 2 at the upper end, and the front fork 10 connecting the front wheel 1A at the lower end are connected so as to be rotatable in a horizontal plane. The head tube 11, the handle bar 13 fixed to the front fork 10 via the handle post 12, the petal crank 14 for rotating the rear wheel 1B via the chain 16 and the sprocket 17, and the petal crank 14 can be rotated. The crank bearing 15 is supported in this manner, the elastic frame 30 is formed by fixing the front end to the head tube 11, the rear end to the axle 1b of the rear wheel 1B, and the middle to the seat tube 9, and the rear end to the crank bearing 15. The front underframe 6 is connected to the front tube 11 and the front end is fixed to the head tube 11, and the rear end is the rear wheel 1B. And a rear underframe 8 which connects the front end to the crank bearing 15 coupled to the axle 1b. The elastic frame 30 includes two elastic rods 30A. The two elastic rods 30A are on both sides of the seat tube 9, with the front end thereof being the head tube 11 and the rear end being the axle 1b of the rear wheel 1B. Is fixed to the seat tube 9. In the bicycle, the seat tube 9 is connected to an upper and lower frame 29 fixed to the crank bearing 15 so as to be movable up and down.

The above bicycle has a very simple structure and can realize a saddle suspension, and if necessary, it can also be realized as a front suspension or a rear suspension with an elastic body that realizes a saddle suspension. .
Further, the bicycle described above has a feature that the saddle load can be balanced and supported by the head tube and the rear wheel, and a comfortable ride can be realized while reducing the lateral displacement and twist of the saddle. In addition, there is also a feature that a comfortable ride can be realized while absorbing impacts on the upper and lower sides of the saddle with an elastic frame.

  The above features are realized by a unique structure that realizes a saddle suspension by connecting both ends to the head tube and the rear wheel and elastically deforming an elastic frame provided with a saddle in the middle. Bicycles with this structure do not realize saddle suspension by connecting the tip of the arm to the head tube like conventional bicycles, but elastically deform the middle of the elastic frame connecting both ends to the frame up and down. , Saddle cushion can be realized. In particular, in the above bicycle, the middle of an elastic frame composed of two elastic rods fixed at both ends to the head tube and the rear wheel is connected to the seat tube, and the elastic rod is elastically deformed to provide a cushion for the saddle. As a result, it is possible to achieve a comfortable ride while reducing lateral displacement and twisting of the frame.

  In addition, the above-mentioned bicycle has an elastic frame that elastically deforms while guiding the seat tube in the vertical direction with the upper and lower frame by connecting the seat tube so that it can move up and down to the upper and lower frame fixed to the crank bearing. Since the seat tube is moved up and down, it is possible to achieve a more comfortable ride by absorbing the impact in the vertical direction with the elastic frame while preventing the lateral displacement of the saddle.

  The bicycle having the suspension of the present invention can be formed into a cylindrical shape in which the seat tube 9 is inserted so that the upper and lower frames 29 can be moved up and down.

In the bicycle having the suspension of the present invention, the front under frame 8 can be connected to the crank bearing 15 so as to tilt up and down.
The above bicycle tilts the front underframe and elastically deforms the elastic frame to realize the front suspension, so the saddle cushion is realized while absorbing the impact of the front wheels with the front suspension, making it more comfortable to ride Can be realized. In particular, this bicycle supports the elasticity of the front suspension with an elastic frame that realizes a saddle cushion, so there is no need to provide a special spring to support the front suspension. The suspension and saddle cushion can be realized.

In the bicycle having the suspension of the present invention, the rear underframe 8 can be connected to the crank bearing 15 so as to be able to tilt up and down.
The above bicycle tilts the rear under frame and elastically deforms the elastic frame to realize the rear suspension, so the saddle cushion is realized while absorbing the impact of the rear wheel with the rear suspension, and the ride is more comfortable Comfort can be realized. In particular, this bicycle supports the elasticity of supporting the rear suspension with an elastic frame that realizes a saddle cushion, so there is no need to provide a dedicated spring to support the rear suspension, and the frame structure makes it easy to rear The suspension and saddle cushion can be realized.

In the bicycle having the suspension of the present invention, the front under frame 6 can be connected to the crank bearing 15 so as to tilt up and down, and the rear under frame 8 can be connected to the crank bearing 15 so as to tilt up and down. .
In the above bicycle, the front underframe and the rear underframe are tilted and the elastic frame is elastically deformed to realize the front suspension and the rear suspension, so the impact of the front wheels is absorbed by the front suspension, and the impact of the rear wheels is also absorbed. A saddle cushion is realized while absorbing with the rear suspension, and a more comfortable ride is achieved. In particular, this bicycle supports the elasticity that supports the front suspension and rear suspension with the elastic frame that realizes the cushion of the saddle, so there is no need to provide a dedicated spring etc. to support the front suspension and rear suspension, The frame structure makes it easy to achieve front suspension, rear suspension, and saddle cushions.

  The bicycle having the suspension according to the present invention is provided with an elastic body 39 between the upper and lower frames 29 and the seat tube 9, and the elastic body 39 can elastically push up the seat tube 9.

  The bicycle having the suspension of the present invention uses the two elastic rods 30A, which are the elastic frames 30, as metal rods, and the metal rods are fixed to the seat tube 9 via the mountain-shaped connecting rods 31. Both ends can be fixed to the metal rod, and the protruding portion can be fixed to the seat tube 9.

It is a side view of the conventional bicycle. It is a side view of the bicycle which has a suspension concerning one example of the present invention. FIG. 3 is an enlarged perspective view of a main part of the bicycle shown in FIG. 2. It is a perspective view which shows the attaching part of the rear-wheel of the bicycle shown in FIG.

  Embodiments of the present invention will be described below with reference to the drawings. However, the examples shown below exemplify a bicycle having a suspension for embodying the technical idea of the present invention, and the present invention does not specify a bicycle having a suspension as the following. Further, in this specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the examples are indicated in the “claims” and “means for solving problems” sections. It is added to the members. However, the members shown in the claims are not limited to the members in the embodiments.

  In the bicycle having the suspension shown in FIG. 2, the front and rear wheels 1, the seat tube 9 having the saddle 2 at the upper end, and the front fork 10 connecting the front wheel 1A at the lower end are connected so as to be rotatable in a horizontal plane. Head tube 11, handlebar 13 fixed to front fork 10 via handle post 12, petal crank 14 for rotating rear wheel 1B via chain 16 and sprocket 17, and petal crank 14 A crank bearing 15 that is rotatably supported, an elastic frame 30 having a front end fixed to the head tube 11, a rear end fixed to the axle 1b of the rear wheel 1B, and a middle fixed to the seat tube 9, and a rear end cranked The front underframe 6 is connected to the bearing 15 and the front end is fixed to the head tube 11, and the rear end is the rear wheel 1B. And a rear underframe 8 which connects the front end to the crank bearing 15 coupled to the axle 1b.

  The seat tube 9 is a cylindrical metal pipe that is not elastically deformed, and a seat post 19 that fixes the saddle 2 to the upper end is inserted and connected. The seat tube 9 is fixed in the middle of the elastic frame 30. The elastic frame 30 has a front end fixed to the head tube 11 and a rear end connected to the axle 1b of the rear wheel 1B. The seat tube 11 moves up and down by elastic deformation of the elastic arm 30. Further, the seat tube 9 is connected so that an upper and lower frame 29 fixed upward to the crank bearing 15 is inserted into the lower end and can be moved up and down. That is, the upper and lower frames 29 are inserted into the lower end portion of the cylindrical seat tube 9 so as to move up and down. The seat tube 19 is connected to the upper and lower frames 29 and fixed to the middle of the elastic frame 30 so that the seat tube 19 can move up and down while maintaining a substantially vertical posture without tilting left and right with respect to the traveling direction of the bicycle. . The seat tube 9 has a seat post 19 connected to the upper end. In order to fix the seat post 19 to the seat tube 9, the seat tube 9 is slightly inclined in a posture in which the upper end portion is moved backward. The seat tube 9 is provided with a tightening band 21 for fixing the upper end to the seat post 19. In order to fix the seat tube 9 to the seat post 19 with the fastening band 21, the seat tube 9 is provided with slits (not shown) in the upper and lower openings. A tightening band 21 is provided in a portion where the slit is provided. The fastening band 21 can be loosened to move the seat post 19 up and down, and is fastened to fix the seat post 19 to the seat tube 9.

  Further, the bicycle of FIG. 2 is provided with a stopper 40 at the lower end of the seat tube 9. The stopper 40 stops the elastic vertical movement of the seat tube 9 by the elastic frame 30 in a locked state in which the seat tube 9 is fixed to the upper and lower frames 29. The stopper 40 is held in a so-called released state in which the seat tube 9 is not fixed to the upper and lower frames 29 in a normal use state. The elastic frame 30 is elastically deformed when the stopper 40 is released, but the elastic frame 30 is not elastically deformed when the stopper 40 is locked. The stopper 40 is held in a locked state only when the user is extremely heavy and is used by a user or when a user who does not require a suspension is used.

  The stopper 40 fastens the lower end portion of the seat tube 9 to the outer peripheral surface of the upper and lower frames 29 to fix the seat tube 9 to the upper and lower frames 29. The sheet tube 9 provided with the stopper 40 is provided with a slit (not shown) at the lower end. The stopper 40 includes a U-shaped fastening tool 41 for fastening the slit portion of the seat tube 9 from the outside, an insertion pin 42 connected to both ends of the fastening tool 41, and a cam lever for fastening the fastening tool 41 with the insertion pin 42. 43. The cam lever 43 has a shape in which a cam is provided at one end and the lever is connected to the cam. The cam is rotated around the insertion pin 42 to provide a cam for fastening the fastening tool 41. The stopper 40 rotates the cam lever 43 to fix the seat tube 9 to the upper and lower frames 29 with the tightening tool 41 to be in a locked state, and rotates the cam lever 43 to release the tightening tool 41 with the cam. .

  As shown in FIG. 3, the elastic frame 30 includes two elastic rods 30 </ b> A, and the two elastic rods 30 </ b> A are disposed on both sides of the seat tube 9. The elastic rod 30A is a metal rod having elasticity, its front end is welded and fixed to the head tube 11, the rear end is connected to the axle 1b of the rear wheel 1B, and the middle is fixed to the seat tube 9. .

  FIG. 4 shows a preferred structure for connecting the rear end of the elastic frame 30 to the rear wheel. The elastic frame 30 in this figure has a fixed plate 30B fixed to the rear end of the elastic rod 30A, and is fixed to the rear wheel axle 1b via the fixed plate 30B. The fixed plate 30B is provided with a long hole 30C into which the rear wheel axle 1b is inserted. Both ends of the axle 1b are inserted into the long hole 30C, and are fixed to the axle 1b with nuts 44 screwed into both ends of the axle 1b. The elastic frame 30 having such a structure can be easily fixed to the axle 1b of the rear wheel and can be easily and easily fixed to the rear wheel that moves back and forth. The rear wheel of the bicycle is fixed to the rear underframe so that it can move back and forth to adjust the tension of the chain, but the elastic frame in Fig. 4 is easy to move to the axle by moving the rear wheel back and forth. Can be fixed securely.

  Although the elastic rod 30A is a linear metal rod, the elastic rod may be curved or may have various shapes that are easily elastically deformed. As shown in FIG. 3, the structure in which the middle of the elastic frame 30 composed of two elastic rods 30 </ b> A is fixed to both sides of the seat tube 9 is such that a downward load acting on the seat tube 9 is fixed to both sides of the seat tube 9. Since the left and right elastic rods 30A are supported while being balanced, there is a feature that the lateral displacement and twist of the elastic frame 30 that is elastically deformed can be reduced.

  In the illustrated elastic frame 30, the middle of an elastic rod 30 </ b> A that is a metal rod is welded and fixed to the seat tube 9 via a connecting rod 31. The connecting rod 31 in the figure is formed by bending a metal rod into a mountain shape, and both ends are fixed to the elastic rod 30A, and an intermediate protruding portion is protruded upward and fixed to the seat tube 9. Since the connecting rod 31 having this structure acts on the elastic rod 30A via the connecting portions at both ends, the load received by the intermediate protrusion from the seat tube 9 acts on the elastic rod 30A while dispersing the load on the seat tube 9. Can be made. Furthermore, the stroke and the deformation direction of the elastic rod 30A that is elastically deformed are controlled by adjusting the fixing positions of the both ends of the connecting rod 31 and the elastic rod 30A. However, the connecting rod is not limited to the above structure, and can be any other structure that can fix the elastic rod to the seat tube. The connecting rod 31, which is a metal rod, is welded and fixed to the elastic rod 30 </ b> A and the seat tube 9. However, the elastic rod can be directly fixed to the seat tube without using a connecting rod. Furthermore, the elastic frame 30 shown in the drawing connects two elastic rods 30 </ b> A via fixed rods 32 before and after the seat tube 9. This elastic frame 30 has two elastic rods 30A as an integral structure, and can further reduce lateral displacement and twist.

  The front fork 10 is a metal pipe or a carbon tube that becomes gradually thinner toward the tip. The illustrated front fork 10 has a shape that curves forward toward the lower end in order to improve straightness with a predetermined caster angle (α). Further, the front fork 10 has a cylindrical portion inserted into the head tube 11, and a portion protruding downward from the head tube 11 is divided into left and right at the upper end portion, and the lower end is set to the axle 1a of the front wheel 1A. It is fixed.

  The head tube 11 has the front end of the elastic frame 30 fixed to the upper part and the front end of the front under frame 6 fixed to the lower part. The head tube 11 shown in the figure fixes the elastic frame 30 and the front under frame 6 apart in the vertical direction. The head tube 11 is a metal pipe inserted so as to be able to rotate the cylindrical portion of the front fork 10, and fixes the front ends of the elastic frame 30 and the front underframe 6. The head tube 11 is also tilted back and forth so that the front fork 10 has a predetermined caster angle (α), that is, tilted so as to move rearward upward, and the elastic frame 30 and the front underframe. 6 is fixed to the front end. The head tube 11 is connected so that the front fork 10 can rotate but does not move up and down.

  The handle bar 13 is fixed to the upper end of the handle post 12 in a T shape, and is connected to the front fork 10 via the handle post 12 by fixing the handle post 12 to the front fork 10. The handle bar 13 is provided with front and rear brake levers (not shown), and handle grips 22 are provided at both ends thereof.

The petal crank 14 has a crank arm 14B fixed to both ends of the crankshaft 14A, and is connected to a crank pin 14C connected to the tip of the crank arm 14B so that the petal 23 can rotate. The crankshaft 14A of the petal crank 14 is connected to the crank bearing 15 so as not to move in the axial direction. Further, the petal crank 14 has a sprocket 17 </ b> A fixed to the outside of the crank bearing 15. The sprocket 17A is connected to the sprocket 17B fixed to the axle 1b of the rear wheel 1B via the chain 16 by the chain 16, and has a structure in which the petal crank 14 is rotated to drive the rear wheel 1B.
In FIG. 3, the sprocket 17 </ b> A and the chain 16 are omitted for easy understanding of the connection structure between the crank bearing 15 and the front underframe 6 and the rear underframe 8 connected thereto.

  The front underframe 6 is a metal pipe or a carbon tube, the rear end is connected to the crank bearing 15, and the front end is fixed to the head tube 11. The front underframe 6 can be a metal pipe or carbon tube that is not elastically deformed, but can be a metal pipe or carbon tube that is somewhat elastically deformed. The rear end of the front underframe 6 is connected to a crank bearing 15 so that it can tilt up and down. The front underframe 6 shown in the drawing has a rear end portion connected to the crank bearing 15 via a tilting shaft 33 that penetrates in a posture parallel to the crankshaft 14A. The crank bearing 15 shown in the figure includes a pair of connecting pieces 34 protruding forward in a vertical posture, and the rear end portion of the front underframe 6 is disposed between the pair of connecting pieces 34. The front under frame 6 is tiltably connected to the crank bearing 15 via a tilt shaft 33 that passes through the pair of connecting pieces 34 and the rear end portion of the front under frame 6.

  The above structure implements the front suspension 3 by tilting the front underframe 6 and elastically deforming the elastic frame 30. That is, when an impact is applied to the front wheel 1A, the bicycle is elastically deformed so that the elastic frame 30 moves the head tube 11 up and down, and the front under frame 6 tilts so that the head tube 11 moves up and down. Thus, the front suspension 3 is realized.

  The suspension stroke by which the front suspension 3 moves the head tube 11 up and down is the elasticity of the elastic frame 30 and the total length of the front underframe 6 (more precisely, the linear distance from the front end of the front underframe 6 to the tilting shaft 33). I can control it. The suspension stroke of the front suspension 3 varies depending on the impact applied to the front wheel 1A and the weight of the user. For example, the elasticity of the elastic frame 30 and the front underframe 6 are adjusted so as to be 1 cm to 5 cm, preferably 2 cm to 3 cm. Set the total length. The front suspension 3 elastically deforms the elastic frame 30 and tilts the front under frame 6 to move the head tube 11, that is, the front wheel 1A up and down. The front suspension 3 due to the elastic deformation of the elastic frame 30 can eliminate any adverse effects caused by the conventional frictional resistance. For this reason, when the front wheel 1A receives an impact, the front wheel 1A can be stroked up and down very smoothly. Therefore, the bicycle of the present invention realizes an extremely comfortable ride while reducing the stroke of the front suspension 3.

  The rear underframe 8 is also a metal pipe or carbon tube, with the rear end connected to the axle 1b of the rear wheel 1B and the front end connected to the crank bearing 15. The rear underframe 8 may be a metal pipe or carbon tube that does not elastically deform, but may be a metal pipe or carbon tube that is somewhat elastically deformed. The front end of the rear underframe 8 is connected to a crank bearing 15 so that it can tilt up and down. The rear underframe 8 shown in the figure has two metal pipes arranged on both sides of the rear wheel 1B. The rear ends of the rear underframe 8 are connected to both ends of the axle 1b of the rear wheel 1B, and the front ends thereof are connected to the crankshaft 14A. Are connected to the crank bearing 15 through a tilting shaft 35 parallel to the shaft. The rear underframe 8 of FIG. 3 connects the front ends of two metal pipes with a connecting pipe 8A, and protrudes behind the crank bearing 15 between the front ends of the two connected metal pipes. The connecting part 36 is arranged. The rear under frame 8 is tiltably connected to the crank bearing 15 via a tilt shaft 35 that passes through the front end portions of the two metal pipes and the connecting portion 36 of the crank bearing 15.

  The above structure realizes the rear suspension 4 by tilting the rear underframe 8 and elastically deforming the elastic frame 30. That is, in this bicycle, the elastic frame 30 is elastically deformed in a state where an impact is applied to the rear wheel 1B, and the rear underframe 8 moves the rear wheel 1B up and down. The rear suspension 4 is realized by tilting so as to be moved.

  The suspension stroke by which the rear suspension 4 moves the rear wheel 1B up and down is the elasticity of the elastic frame 30 and the total length of the rear underframe 8 (more precisely, the linear distance from the axle 1b of the rear wheel 1B to the tilting shaft 35). I can control it. The suspension stroke of the rear suspension 4 varies depending on the impact applied to the rear wheel 1B and the weight of the user. For example, the elasticity of the elastic frame 30 and the rear underframe 8 are 2 cm to 10 cm, preferably 3 cm to 5 cm. Set the total length. The rear suspension 4 elastically deforms the elastic frame 30 and tilts the rear underframe 8 to move the rear wheel 1B up and down. As with the front suspension 3, the rear suspension 4 due to the elastic deformation of the elastic frame 30 can eliminate the adverse effects caused by the conventional frictional resistance. For this reason, when the rear wheel 1B receives an impact, the rear wheel 1B can be stroked up and down very smoothly. Therefore, the bicycle of the present invention can realize a very comfortable ride even if the stroke of the rear suspension 4 is reduced.

  The upper and lower frames 29 are metal pipes and are fixed to the crank bearing 15. The upper and lower frames 29 shown in FIG. 3 are fixed to the upper surface of the crank bearing 15 in a standing posture protruding upward from the crank bearing 15. The upper and lower frames 29 are inserted into the lower end portion of the seat tube 9 so as to be movable up and down. The upper and lower frames 29 and the seat tube 9 are arranged coaxially with the seat tube 9 so as to be relatively movable in a low resistance state. Further, the bicycle shown in FIG. 2 is provided with an elastic body 39 between the upper and lower frames 29 and the seat tube 9 as indicated by a chain line in the drawing, and the elastic body 39 elastically pushes up the seat tube 9. ing. The elastic body 39 shown in the figure is a pressing spring made of a coil spring, and is arranged inside the seat tube 9 so as to urge the upper and lower frames 30 inserted from the lower end in the pushing direction. Since this bicycle supports the load applied to the saddle 2 by both the elastic body 39 and the elastic frame 30, it can be used even by a heavy user. However, the elastic body can be any other structure that elastically pushes up the seat tube. Furthermore, the bicycle of the present invention does not necessarily include an elastic body, and the elastic body can be omitted.

1 ... wheel 1A ... front wheel
1a ... Axle
1B ... Rear wheel
DESCRIPTION OF SYMBOLS 1b ... Axle 2 ... Saddle 3 ... Front suspension 4 ... Rear suspension 6 ... Front under frame 8 ... Rear under frame 8A ... Connection pipe 9 ... Seat tube 10 ... Front fork 11 ... Head tube 12 ... Handle post 13 ... Handle bar 14 ... Petal crank 14A ... crankshaft
14B ... Crank arm
14C ... Crank pin 15 ... Crank bearing 16 ... Chain 17 ... Sprocket 17A ... Sprocket
17B ... Sprocket 19 ... Seatpost 21 ... Tightening band 22 ... Handle grip 23 ... Petal 29 ... Upper / lower frame 30 ... Elastic frame 30A ... Elastic rod 30B ... Fixed plate 30C ... Long hole 31 ... Connecting rod 32 ... Fixed rod 33 ... Tilt shaft 34 ... Connecting piece 35 ... Tilt shaft 36 ... Connecting portion 39 ... Elastic body 40 ... Stopper 41 ... Fastening tool 42 ... Inserting pin 43 ... Cam lever 44 ... Nut 101 ... Rear wheel 103 ... Front suspension 104 ... Rear suspension 106 ... Under frame 110 ... Front fork 111 ... Head tube

Claims (7)

Connect the front and rear wheels (1), the seat tube (9) with the saddle (2) at the upper end, and the front fork (10) connecting the front wheel (1A) to the lower end so that they can rotate in a horizontal plane. Head tube (11), handlebar (13) fixed to front fork (10) via handle post (12), rear wheel (1B) via chain (16) and sprocket (17) A petal crank (14) that rotates the crankshaft, and a crank bearing (15) that supports the petal crank (14) so that it can rotate,
An elastic frame (30) in which the front end is fixed to the head tube (11), the rear end is fixed to the axle (1b) of the rear wheel (1B), and the middle is fixed to the seat tube (9), and the rear end is the crank A front underframe (6) is connected to the bearing (15) and the front end is fixed to the head tube (11), and a rear end is connected to the axle (1b) of the rear wheel (1B) and the front end is connected to the crank. A rear underframe (8) connected to the bearing (15),
The elastic frame (30) includes two elastic rods (30A), and the two elastic rods (30A) are on both sides of the seat tube (9), and the tips thereof are attached to the head tube (11). The rear end is fixed to the axle (1b) of the rear wheel (1B), and the middle is fixed to the seat tube (9),
A bicycle having a suspension in which the seat tube (9) is connected to an upper and lower frame (29) fixed to the crank bearing (15) so as to be vertically movable.   The bicycle having a suspension according to claim 1, wherein the seat tube (9) has a cylindrical shape in which the upper and lower frames (29) are inserted so as to be movable up and down.   The bicycle having a suspension according to claim 1 or 2, wherein the front underframe (6) is connected to the crank bearing (15) so as to be able to tilt up and down.   The bicycle having a suspension according to claim 1 or 2, wherein the rear underframe (8) is connected to the crank bearing (15) so as to be able to tilt up and down.   The front under frame (6) is connected to the crank bearing (15) so that it can tilt up and down, and the rear under frame (8) is connected to the crank bearing (15) so as to tilt up and down. A bicycle having a suspension according to claim 1 or 2.   An elastic body (39) is provided between the upper and lower frames (29) and the seat tube (9), and the elastic body (39) elastically pushes up the seat tube (9). 5. A bicycle having the suspension described in any one of 5 above.   The two elastic rods (30A) as the elastic frame (30) are metal rods, and the metal rods are fixed to the seat tube (9) via the mountain-shaped connecting rod (31), and the mountain-shaped connecting rod (31) A bicycle having a suspension according to any one of claims 1 to 6, wherein both ends are fixed to metal rods and the projecting portion is fixed to the seat tube (9).

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