JPH0382689A - Two-front-wheel type tricycle - Google Patents

Abstract

PURPOSE:To improve turnability and traveling stability by providing a tricycle where a main frame holding one rear wheel and a front wheel frame 32 holding two front wheels are connected in a very low degree of freedom through a steering shaft. CONSTITUTION:A rear wheel 21 and its drive device, a saddle 30 and so on are assembled on a main frame 22 consisting of a head pipe 22a, a main pipe 22b and so on, and the upper side pipe 31b of a steering shaft 31 is inserted. The middle part of the steering shaft 31 is bent, and the bent part is formed in a stepped shape through a connecting member 31a. Moreover, the center pipe 32a of a front wheel frame 32 provided integratedly with a pair of right and left front fork supporting pipes 32b through an arm pipe 32c is inserted rotatably into the lower pipe 31d positioned at the lower part of the connecting member 31a. In addition, a front fork 23 is assembled on the front fork supporting pipe 32b of the front wheel frame 32, and a front wheel 20 is fitted on the front fork 23.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a two-wheel front tricycle having two front wheels and one rear wheel.

(Prior Art) Figs. 13 to 15 show an example of a conventional three-wheeled bicycle, which is a two-wheeled three-wheeled bicycle with one front wheel and two rear wheels.

In other words, in the figure, 1 is the main frame, 1a is the head pipe, 1b is the main pipe, IC is the vertical pipe, 2 is the front wheel, and 3
is the front fork, 4 is the handle post, 5 is the handle, 6
is a rear wheel, 7 is a rear axle, 8 (see Figures 14 and 15) is an axle frame connecting the left and right rear axles 7, and 9 is a rocking motion of the vehicle body connected to the main frame 1 via a connecting member 10. The central shaft 11 is a bracket protruding from each side of the shaft 9, and these brackets 11 can rotate upward about the shaft 9. Reference numeral 12 denotes restoring springs that are stretched between the outer ends of the left and right brackets 11 and the axle frame 8, respectively.

Further, 13 (see FIG. 13) is a seat post, 14 is a sadonobe 15 is a crankshaft, 16 is a crank arm, 17 is a pedal, and 18 is a chain.

(Problem to be Solved by the Invention) However, when the conventional three-wheeled bicycle as described above tries to turn, centrifugal force acts toward the outside of the turn. The vehicle body must be tilted toward the inside of the turn by trunk operation.

FIG. 15 shows a state in which the vehicle body is tilted to the left in the figure by the rider's trunk operation.

In other words, in the conventional tricycle shown in Figs. 13 to 15,
In order to prevent the main frame from tipping over easily when turning, the main frame is configured to be able to swing left and right, allowing the center of gravity to move left and right.
By the action of 2, it returns to the upright position. However, in this case, the movement of the center of gravity to the left or right is left to the rider's trunk operation, and people who cannot ride a bicycle well cannot move the bicycle flexibly, resulting in unstable control.

Additionally, a three-wheeled bicycle with one front wheel and two rear wheels usually moves forward by driving one of the rear wheels, but for example, when a three-wheeled bicycle with left rear wheel drive turns to the left, the vertical load applied to the drive wheel due to centrifugal force increases. As a result, the driving force becomes insufficient.

Furthermore, tricycles with two rear wheels have the two rear wheels fixed in parallel orientation, so when turning, the rear wheels skid sideways, resulting in poor turning performance and the disadvantage of being unable to turn in a tight corner. Furthermore, when you get off a tricycle with two rear wheels and walk while pushing the tricycle, your feet hit the rear wheels, making it difficult to walk.Also, the rear of a tricycle with two rear wheels is heavy, making it difficult to lift it to change direction or put it in a garage. The problem was that it was difficult.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides two sets of support pipes that rotatably support two sets of front forks that respectively support the front two wheels of a two-wheeled tricycle. is integrally connected to the center pipe, and a balancing rod is provided protruding rearward from this center pipe to form a front wheel frame.The part that supports the rear wheel and the head pipe are connected by a main pipe, and a balancing rod is connected to this main pipe. An engaging portion is provided to form a main frame, and the intermediate portion of the steering shaft is bent, and this bent portion is formed into a stepped shape via a connecting member, and the front wheel frame is provided below the bent stepped portion. A center pipe is rotatably fitted, a head pipe of the main frame is rotatably fitted above the bent step, and the balancing rod is engaged with the rod engaging portion and fixed to the steering shaft. The front two-wheel type tricycle is configured so that the left and right front wheels can be steered by operating the handle.

Further, as a second invention, an elastic body having a repulsion effect is interposed between the main frame and the balancing rod of the front two-wheel tricycle of the first invention.

(Function) Since the tricycle of the present invention is configured as described above, the main frame holding the rear wheel and the front wheel frame holding the front two wheels have almost the same degree of freedom through the steering shaft. It is connected without being connected. When driving straight, the steering shaft tilts only in the longitudinal direction, so the main frame is in an upright state, and when the steering wheel is operated to turn, the upper half of the steering shaft tilts in accordance with the steering angle of the steering wheel. As the bike begins to lean toward the inside of the turn, the main frame also leans toward the inside of the turn, and the rider naturally operates his or her trunk to move the center of gravity toward the inside of the turn.

In particular, in the present invention, since the bent portion of the steering shaft is formed in a stepped manner through the connecting member, the movement of the center of gravity with respect to the inclination of the steering shaft can be increased, thereby reducing the discomfort felt by the driver.

In addition, in the second aspect of the present invention, since an elastic body having a repulsion effect is interposed between the main frame and the balancing rod, the restorability of returning the steering shaft to the neutral position is enhanced, and the bicycle is The stability of running can be improved by increasing the restoring force against disturbances that the front wheels receive while running.

Therefore, the tricycle of the present invention allows even people who cannot ride a bicycle to ride it stably without falling over.

Furthermore, since the driving wheels are the rear wheels, there is no fear that the driving wheels will lift up or skid, and the rear wheels will not get in the way when the tricycle is being pushed around.

Furthermore, the rear axle type tricycle has a light rear part, making it easier to lift the rear part to change direction or park the vehicle in a garage.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 8. In the figure, 20 is a front wheel, 21 is a rear wheel, 22 is a main frame, 23 is a front fork, 24 is a hand crank 25 is a crankshaft, 26 is a crank arm, 27 is a pedal, 28 is a chain case, 29 is a seat post, 30 is a It's a saddle.

FIG. 2 shows the details of the main frame 22 in this embodiment, 22a is a head pipe, 22b is a main pipe, 22C is a hanger lug, 22d is a vertical pipe, 22
e is the chainstay, 22f is the back hawk,
22g is a channel-shaped member fixed to the lower surface of the rear part of the main pipe 22b as a rod engagement part.

FIG. 3 shows an embodiment of the steering shaft 31. This steering shaft 31 has an intermediate portion of about 7.5 degrees (third
(see θ in the figure), and the bent portion is formed into a stepped shape via a connecting member 31a.

That is, 31b is an upper pipe connected above the bent step 31a, and a screw 31C is formed at the upper end thereof.

31d is a lower pipe, and a screw 31e is attached to the lower end of the pipe.
and a cut groove 31f (see FIG. 7) are formed.

FIG. 4 shows an embodiment of a front wheel frame 32 for supporting two front wheels 20 via front forks 23 and pivotally supporting the steering shaft 31 via a center pipe. In other words, 32a is the steering shaft 3
A center pipe that fits into the lower pipe 31d of 1,
Reference numeral 2b indicates front fork support pipes fixed to both left and right sides of the center pipe 32a via arm pipes 32C, and 32d indicates a balancerong rod protruding rearward from the back surface of the center pipe 32a.

In this embodiment, as shown in FIG. 1.5.6, necessary parts such as the rear wheel 21o, its drive device, saddle 30, etc. are assembled to the main frame 22, and the main frame 22 is Insert the upper pipe 31b of the steering shaft 31 into the head pipe 22a, completely fit the center pipe 32a of the frame 32 into the lower pipe 31d of the steering shaft 31, and connect the rear end of the balancing rod 32d to the main frame 22.
into the rod engaging portion 22g.

And the left and right front fork support pipes 3 of the front wheel frame 32
The front fork 23 is assembled to 2b, the front wheel 20 is attached to this front fork 23, and as shown in FIG.
When a steering shaft 31 is turned left and right via a handle 24 (see FIG. 1), left and right front wheels 20 are appropriately steered.

That is, as shown in FIG. 7, the steering shaft 31 protrudes below the center pipe 32a of the front wheel frame 32.
An elliptical plate 33 is fitted into the lower end of the plate 33 through two semicircular holes 33a, and a plate 35 having a bifurcated protrusion 35a is attached to the lower surface of the plate 33 via a bush 34. do.

That is, a hole 35b provided in the plate 35 is fitted into the lower end of the steering shaft 31, and a disk-shaped elastic body 36 is inserted into the arc-shaped portion 35C between the bifurcated protrusions 35a of the plate 35.
The bolts 37 are inserted into the holes 33b of the plate 33 and the center holes 36a of the elastic body 36, and fastened with nuts 38.

As shown in FIG. 6, rods 39 are provided protruding from each of the bifurcated protrusions 35a of the plate 35, and one end of a rod 40 is connected to the tips of these rods 39 by a pin 41. The base of the rod 43, which is connected to the other end by a pin 42, is fixed to the front axle 44.

That is, by doing as described above, steering can be performed by rotating the steering shaft 31 left and right through the handle 24 and rotating the left and right front wheels 20 around the front fork support pipe 32b. In order to make the tricycle turn smoothly, this front wheel twisting device is constructed by appropriately adjusting the dimensions of each rod 39, 40, 43, or the angle of the bifurcated protrusion 35a of the plate 35. It is possible to use the so-called Ackermann type steering in which the left and right front wheels have different steering angles.

Further, in the second aspect of the present invention, as shown in FIG. 8, the end of the balancing rod 32d of the front wheel frame 32 is inserted into the rod engaging portion 22g provided on the main pipe 22b of the main frame 22, A coil spring 45 is interposed between the balancing rod 32d and the main pipe 22b as an elastic body having a repulsion effect.

Next, the operation of the two-wheel front tricycle of the present invention constructed as described above will be explained.

The tricycle shown in FIG. 2 can move forward when the rider straddles the saddle 30 and depresses the pedal 27, like a normal bicycle, and turns by turning the left and right front wheels 20 by operating the handlebar 24. However, the tricycle of the present invention can obtain a centripetal force corresponding to the centrifugal force generated during the turn by automatically tilting the main frame 22 toward the inside of the turn.

Next, the principle will be explained with reference to FIG.

That is, the front wheel frame 32 is held parallel (horizontal) to the road surface GL by the left and right front wheels 20.

Therefore, the position relative to the road surface is restricted.

FIG. 9(a) is a front view of the steering shaft 31 shown as a side view in FIG. 3, in which the upper pipe 31b and the lower pipe 31d are vertical.

That is, when the bicycle is traveling straight, the steering shaft 31 is in this state.

The solid line diagram in FIG. 9(b) shows this straight-ahead state, in which the head pipe 22a of the main frame 22 and the center pipe 32a of the front wheel frame 32 are both perpendicular to the road surface GL. Therefore, the main frame 22 of this bicycle is upright when traveling straight.

Next, FIG. 9(C) shows the steering shaft 31 viewed from the front when the handle 24 is rotated 90 degrees to the left. That is, in this case, since the lower pipe 31d does not tilt to the left or right, the axis of the upper pipe 31b tilts to the left (to the right) by the angle θ. Therefore, as shown by the two-dot chain line in FIG. 9(b), the head pipe 22a of the main frame 22 is also inclined by an angle θ, which generates a centripetal force when turning. That is, when the tricycle of the present invention turns, the main frame 22 always faces forward and tilts left and right. This movement of the main frame 22 in the opposite direction occurs when the end of the balancing rod 32d, which is formed integrally with the front wheel frame 32, is inserted into a rod engaging portion 22g having a rectangular groove provided on the lower surface of the main pipe 22b of the main frame 22. This is ensured by the fact that it is inserted so that it can slide slightly only in the front and back and up and down directions. As a result, the central plane of the main frame 22 is inclined with respect to the vertical plane as the handle 24 rotates (
It will move so that it has a bank angle).

The present applicant previously filed a two-wheel front tricycle in Japanese Patent Application No. 1-88152, but the steering shaft 46 of this tricycle does not have a bent step as shown in FIG.

Therefore, a tricycle using this steering shaft 46 is as shown in FIG. 11(a), and a tricycle of the present invention is as shown in FIG. 11(b).

In this Fig. 11, if the intersection of the vertical axes is ○ and the center of gravity of the occupant is G, then in Fig. 11(a), ○ ~
G-1, whereas in the one in Figure 11(b),
0 to G=f+m. Therefore, in order to move the center of gravity G horizontally by e, in the case of FIG. 11(a), the main frame 22 must be tilted by an angle λ, whereas in the case of FIG. In this case, the main frame 22 may be tilted by an angle λ'. And λ λ〉λ′.

Therefore, in the tricycle of the present invention, the inclination of the main frame 22 for the same amount of movement of the center of gravity can be smaller than that of the tricycle shown in FIG. 111 (a). Therefore, the present invention can reduce the sense of discomfort to the operator.

Further, in the second aspect of the present invention, an elastic body 45 having a repulsive action is interposed between the main pipe 22b of the main frame 22 and the balancing rod 32d of the front wheel frame 32. A) and (b) will be explained.

That is, FIG. 12(a) shows a state in which the tricycle of the present invention is traveling straight, and in this case, the distance between the main pipe 22b and the balancing rod 32d is D.

Further, FIG. 12(b) shows a state in which the handle is turned 90 degrees, and in this case, the distance between the main pipe 22b and the balancing rod 32d is d.

Since D>d, the elastic body 45 having a repulsive action
As a result, the handle 24 of this tricycle is constantly trying to return to the neutral position.

Therefore, according to the second aspect of the present invention, it is possible to increase the restoring force against external disturbances that the front wheel receives while the bicycle is running, thereby improving the stability of running the bicycle.

(Effects of the Invention) Since the tricycle of the present invention is configured as described above, the main frame 22 holding the rear wheel and the front wheel frame 32 holding the two front wheels are connected to each other via the steering shaft 31. They are stuck in a state with almost no freedom. Since the steering shaft 31 is tilted only in the front-rear direction when driving straight, the main frame 22 is in an upright state, and when the steering wheel 24 is operated to turn, the upper half of the steering shaft 31 is moved from the steering wheel 24. The main frame 22 tilts to the inside of the turn depending on the steering angle.
As a result of leaning to the inside of the turn, the rider will naturally operate his or her trunk to move the center of gravity to the inside of the turn.

In particular, in the present invention, since the bent portion of the steering shaft 31 is formed in a stepped shape via the connecting member 31a, the movement of the center of gravity with respect to the inclination of the steering shaft 31 can be increased, thereby reducing the discomfort felt by the operator.

Furthermore, in the second aspect of the present invention, since the elastic body 45 having a repulsion effect is interposed between the main frame 22 and the balancing rod 32d, the restorability of returning the steering shaft 31 to the neutral position is enhanced. The stability of running can be improved by increasing the restoring force against disturbances that the front wheel 2o receives while the bicycle is running.

Therefore, the tricycle of the present invention allows even people who cannot ride a bicycle to ride it stably without falling over.

Furthermore, since the driving wheels are the rear wheels, there is no fear that the driving wheels will lift up or skid, and the rear wheels will not get in the way when the tricycle is being pushed around.

Furthermore, the rear axle type tricycle has a light rear part, making it easier to lift the rear part to change direction or park the vehicle in a garage.

As described above, the present invention provides many effects that significantly improve the performance of this type of tricycle.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the tricycle of the present invention, Fig. 2 is a perspective view of its main frame, Fig. 3 is a side view of the steering shaft, Fig. 4 is a perspective view of the front wheel frame, and Fig. 5 is the main frame and front wheel. Figure 6 is a perspective view of the front wheel steering device; Figure 7 is a perspective view of various connecting members at the lower end of the steering shaft; Figure 8 is the engagement of the main pipe and the balancing rod. Figures 9(a), (b), and (C) are explanatory diagrams of the tilting action of the main frame during turning; Figure 10 is a side view of a conventional steering shaft; Figure 11 (
a) and (b) are diagrams explaining the relationship between the steering axis and the main frame inclination, Figures 2 (a) and (b) are diagrams explaining the effect of the elastic body provided on the balance rod, and Figure 13 is an example of a conventional three-wheeled bicycle. A perspective view showing the first
4 and 15 are explanatory diagrams showing the relationship between the axle frame and the main frame of the subsequent two wheels. 20...Front wheel 21...Rear wheel 22...
・Main frame 22a...Headpipe 22b
...Main pipe 22g...Rod engaging part 23
...Front Hawk 24...Handle 31...
- Steering shaft 31a...Connecting member (bending step) 31b...Upper pipe 31d...Lower pipe 32...Front wheel frame 32a...Center pipe 32b...Front fork support pipe 32d...・Balancing rod 45...Coil spring (elastic body) Fig. 1 Fig. 2 Fig. 4 Fig. 5 Fig. 11 (a) (b) Fig. 12 (a)

Claims (1)

[Scope of Claims] 1. Two sets of support pipes that rotatably support two sets of front forks that respectively support the front two wheels of a two-wheeled tricycle are integrally connected to a center pipe, and the two sets of support pipes are integrally connected to a center pipe, and A front wheel frame is formed by protruding balancing rods, a main pipe connects the rear wheel supporting part and a head pipe, and a rod engaging part is provided on this main pipe to form a main frame, and a steering shaft The middle part of the front wheel frame is bent, and this bent part is formed into a stepped shape through a connecting member, and the center pipe of the front wheel frame is rotatably fitted to the lower side of this bent part. The head pipe of the main frame is rotatably fitted to the upper side, and the balancing rod is engaged with the rod engaging portion, so that the left and right front wheels can be steered by operating a handle fixed to the steering shaft. A two-wheeled tricycle with two front wheels. 2. Two sets of support pipes that rotatably support two sets of front forks that respectively support the front two wheels of a two-wheel tricycle are integrally connected to a center pipe, and a balancing rod is provided protruding rearward from the center pipe. A front wheel frame is formed, a part supporting the rear wheel and a head pipe are connected by a main pipe, and a rod engaging part is provided on this main pipe to form a main frame, and the middle part of the steering shaft is bent. At the same time, this bent portion is formed into a stepped shape via a connecting member, the center pipe of the front wheel frame is rotatably fitted under the bent stepped portion, and the main frame is fitted above the bent stepped portion. The head pipe is rotatably fitted, the balancing rod is engaged with the rod engaging portion, and an elastic body having a repulsion action is interposed between the main frame and the balancing rod, and the balancing rod is fixed to the steering shaft. A tricycle with two front wheels characterized by being able to steer the left and right front wheels by operating the handle.