JPH02267092A - Two front-wheel type tricycle - Google Patents

Abstract

PURPOSE:To secure a stable running by combining two sets of holding pipes to hold rotatable two sets of front forks which hold the two front wheels of a two front-wheel type tricycle, with a center pipe integrally. CONSTITUTION:While a real wheel 21 and its driving device and the like are installed to a main frame 22, the upper side pipe of a steering shaft 31 is inserted to a head pipe 22a of the frame 22, the center pipe 32a of a frame 32 is geared to the lower pipe of the shaft 31, and the rear end of a balancing rod 32d is inserted to a rod gearing part 22g of the frame 22. While front forks 23 are installed to the front fork holding pipes 32b at the left side and the right side of the front wheel frame 32, front wheels 20 are installed to the forks 23, The front wheels 20 at the both sides can be rotated and steered adequately with the front fork holding pipes 32b as the centers, when the shaft 31 is turned to the left and to the right through a handle 24. By inclining the frame 22 to the inner side of the rotation automatically in the turning, a centripetal force responding to the centrifugal force generated in the turning can be obtained.

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) Figures 9 to 11 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.

That is, in the figure, 1 is the main frame, 1a is the head pipe, 1b is the main pipe, 1c 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 Fig. 1011) is an axle 7+z-m 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 1o. The central shaft 11 is a bracket protruding from each side of the shaft 9, and these brackets 1 can be rotated upwards about the shaft 9. 12
are restoring springs stretched between the outer ends of these left and right brackets 11 and the axle frame 8, respectively.

Further, 13 (see FIG. 9) is a seat post, 14 is a saddle, 15 is a crankshaft, 16 is a crank arm, 17 is a pedal, and 18 is a chain.

(Problem B to be Solved by the Invention) However, in the conventional three-wheeled bicycle as described above, when trying to turn, centrifugal force acts toward the outside of the turn, so in order to counteract this centrifugal force, The rider must use his or her trunk to tilt the vehicle toward the inside of the turn.

FIG. 11 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 three-wheeled bicycles shown in Figs. 9 to 11, in order to prevent the bicycle from easily falling over when turning, the main frame is configured to be able to swing from side to side, allowing the center of gravity to move from side to side. At the same time, the restoring spring 12 is activated at the end of the turn.
The action is to return it 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 front wheel frame is formed by connecting a balancing rod to the rear of this center pipe. A main frame is formed by providing a retaining part, the middle part of the steering shaft is bent, the center pipe of the front wheel frame is rotatably fitted to the lower side of the bent part, and the main frame is attached to the upper side of the bent part. At the same time, the head pipe is rotatably fitted, and the balancing rod is engaged with the rosid engagement part, so that the left and right front wheels can be steered by operating the handle fixed to the steering shaft, so that the front two-wheel tricycle can be operated. Configure.

(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. Because it will tilt towards the inside of the turn,
As the main frame also leans toward the inside of the turn, the rider naturally operates his or her trunk to move the center of gravity toward the inside of the turn.

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, because the rear part of a tricycle with a rear wheel cutting system is light, it is easy 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 the front wheel, 21 is the rear wheel, 22 is the main frame, 23 is the front fork, 24 is the handle, 25 = 5 is the crankshaft, 26 is the crank arm, 27 is the pedal,
28 is a chain case, 29 is a seat post, and 30 is a saddle.

FIG. 2 shows the details of the main frame 22 in this embodiment, 22a is a head pipe, 221 is a main pipe, 22c is a hanger lug, 22d is a vertical pipe,
2e is the chainstay, 22f is the back balk,
22g is a channel-shaped member fixed to the lower surface of the rear part of the main vibe 22b as a rod engagement part.

FIG. 3 shows an embodiment of the steering shaft 31, which has a middle portion bent by about 10 degrees. In other words, 31a is a two-sided pipe, and a breakout 31b is formed at its upper end. Further, 31c is a lower pipe, and a screw 31d and a slot 31e are formed at the lower end thereof. 31f is a bending joint that connects the upper pipe 31a and the lower pipe 31c.

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 31C of No. 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 front fork support pipe extending rearward from the back surface of the center pipe 32a.
It is a balancing rod that protrudes from J.

In this embodiment, as shown in FIG. Insert the upper pipe 31a of the steering shaft 31 into the head pipe 22a of the steering shaft 31, completely fit the center pipe 32a of the frame 32 into the lower pipe 31c 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 boke support pipes 3 of the front wheel frame 32
At the same time, assemble the front balk 23 to the front fork 2b and attach the front wheel 20 to the front fork 23, 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. 6, 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 disc-shaped elastic body 36 is fitted 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 hole 36a of the elastic body 36, and fastened with nuts 38.

As shown in FIG. 5, 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 with 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 steering device controls the left and right front wheels by appropriately determining the dimensions of each rod 3940, 43 or the angle of the bifurcated protrusion 35a of the plate 35. It is possible to use a so-called Ackermann type steering wheel with different steering angles.

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. 1 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 by the left and right front wheels 20. Therefore, the position relative to the road surface is restricted. When the handle 24 is rotated, the lower pipe 31c of the steering shaft 31 to which the handle 24 is fixed rotates around the axis of the center pipe 32a of the front wheel frame 32, so that the upper pipe 31a has its bending point as its apex. This results in a circular motion on the circumferential surface of the conical surface. For this reason, the head pipe 22a of the main frame 22, which is pivotally connected to the upper pipe 31a, rotates relatively around the axis of the upper pipe 31a while being fitted with the upper pipe 31a, so that the main frame 22 always faces forward. 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 (has a bank angle) with respect to the vertical plane as the handle 24 rotates.
You will exercise like this.

Now, as shown in FIG. 7, the bending point of the steering shaft 31, that is, the axis of the upper pipe 31a and the lower pipe 31
The intersection of the axes of c is the origin O, and the orthogonal coordinate system x,
In addition to determining y and z, the axis CC' of the center pipe 32a of the front wheel frame 32,! :, the angle formed with the X-axis parallel to the ground is θ, and the bending angle of the steering shaft 31 is zo.

Furthermore, when a point P is taken on the axis of the upper pipe 31a of the steering shaft 31 (that is, the axis of the handle stem) and the handle 24 is rotated by an angle ω around the axis, the lower pipe 31c of the steering shaft 31 is The center pipe 32a is rotated in the same direction by an angle ω' - ωcos 515, and the point P on the axial plane moves on a circle 0' passing through the point P perpendicular to the axis ', and reaches the point Q. At this time, /POQ y
In other words, ZP゛OQ' projected on the Z screen indicates the inclination angle of the main frame 22 with respect to the vertical plane.

Figure 8 shows the above-mentioned angles θ and ψ by applying practical values.
The graph shows the calculated inclination angle ZP'OQ' of the main frame 22 when the handle rotation angle ω is changed from -45'' to +45°.

That is, according to FIG. 8, it can be seen that the inclination angle of the main frame 22 changes approximately in proportion to the rotation angle of the handle 24.

(Effects of the Invention) Since the tricycle of the present invention is configured as described above, the rear wheel
The main frame 22 holding the steering shaft 3 and the front wheel frame 32 holding the two front wheels 20 are
1 with almost no degree of freedom. When driving straight, the steering shaft 31 is tilted only in the longitudinal direction, so the main frame 22 is in an upright state when viewed from the front, and when the steering wheel 24 is operated to turn, the upper half of the steering shaft 31 Since the main frame 31a tilts toward the inside of the turn according to the steering angle of the handlebar 24, the main frame 22 also tilts toward the inside of the turn.
The rider also naturally operates his or her trunk to move the center of gravity toward the inside of the turn.

Therefore, according to the tricycle of the present invention, even a person who cannot ride a bicycle well can ride the bicycle stably without falling over.

Furthermore, since the tricycle of the present invention has rear wheels as drive wheels, there is no fear that the drive wheels will lift up or skid, and the rear wheels will not get in the way when the tricycle is pushed around.

Furthermore, since the rear axle type tricycle has a light rear part, it is easy to lift the rear part to change directions or to park the vehicle in a garage.

[Brief Description of the 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 perspective view of the steering shaft, Fig. 4 is a perspective view of the front wheel frame, FIG. 5 is a perspective view of the front wheel steering device, FIG. 6 is a perspective view showing various connecting members at the lower end of the steering shaft, FIG. 7 is a perspective view for explaining the operation showing the state of connection between the main frame and the front wheel frame, Fig. 8 is a graph showing the relationship between the rotation angle of the handlebar and the inclination angle of the main frame, Fig. 9 is a perspective view showing an example of a conventional tricycle, and Fig. 10
11 are explanatory diagrams showing the relationship between the axle frame and the main frame of the two subsequent wheels. 20...Front wheel 21...Rear wheel 22...
・Main frame 22a...Head pipe 22b
...Main pipe 22g...Rod engaging part 23
...Front Hawk 24...Handle 31...
・Steering shaft 31a...Upper pipe 31c・
...Lower pipe 31f...Bending joint 32...
Front wheel frame 32a...center pipe 32b
...Front fork support pipe 32d...Balancing slot 42 (bin)

Claims (1)

[Claims] 1. Two sets of support pipes that rotatably support two sets of front forks that support the front two wheels of a tricycle with two front wheels 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 by connecting the rear wheel supporting part and a head pipe 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. , a center pipe of the front wheel frame is rotatably fitted to the lower side of the bent portion, a head pipe of the main frame is rotatably fitted to the upper side of the bent portion, and the balancing rod is engaged with the rod. 1. A front two-wheeled tricycle, characterized in that the left and right front wheels can be steered by operating a handle that is engaged with the steering shaft and fixed to the steering shaft.