JPS6313882A - Tension regulator for belt drive type bicycle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a tensioning device for belt-driven bicycles.

BACKGROUND OF THE INVENTION Chain drives are commonly used as devices for transmitting the rotation of the crankshaft of a bicycle to the rear wheels, but there are other drive systems that use toothed belts.

In such a drive system using a toothed belt, when the driving force is strong, the belt stretches, causing tooth skipping between the small pulley and the belt. To prevent this, conventional
A device like the one shown in the figure was used to take up the slack in the lower belt.

In the figure, reference numeral 1 denotes a chainstay that forms part of the frame of the bicycle, and a rotating shaft 11 is provided in contact with the chainstay, and a support fitting 9 is rotatably supported around this rotating shaft 11. Idlers 7 are installed at both the upper and lower ends of the support bracket.
a and 7b are rotatably supported. The action of this device is that when a large driving force is applied to the belt 6, the idler 7a
is pushed in the H direction, and the idler 7b accordingly pushes up the lower side of the belt to eliminate slack in the belt.

Problems to be Solved by the Invention However, in this method, as shown in Fig. 4, the support fitting is provided with a cantilever structure that passes through one side of the belt (the center side of the bicycle body) in order to facilitate the removal of the belt. and idler 7
Since the belt supports parts a and 7b, there is an inconvenience that the belt comes off to the opposite side of the support metal fitting (in the J direction).

Means for Solving the Problems and Means of the present invention for solving the above problems is that instead of setting the rotation axis of the idler at right angles to the running direction of the belt, the rotation axis of the idler is set at a certain angle θ from the right angle. The purpose of this is to prevent the belt from coming off by rotating it in the running direction of the belt.

Function: When the rotating shaft of the idler that rotates in contact with the belt is rotated from a position perpendicular to the running direction of the belt, the belt receives a lateral force from the idler while running, and the belt constantly tries to move toward the metal fitting. It works and you don't have to worry about it coming off the other side.

EXAMPLE Hereinafter, an example of the present invention will be described based on the accompanying drawings.

In Figure 2, 1 is a chainstay, which forms part of the bicycle frame, and has a large pulley 2 and a small pulley.
A rotating shaft of 3 is fixed to both ends thereof, and the small pulley 3 and the thick pulley 2 are each rotatably supported.

A crank 5 that pivotally supports a pedal 4 is fixed to the dog pulley 2, and by rotating the pedal 4, the large pulley 2 can be rotated.

The large pulley 2 and the small pulley 3 are belt pulleys. 6
is a belt, and has teeth on the inside as shown in Figure 5. The large and small pulleys have tooth patterns that mesh with the tooth patterns, and such a system is known as a timing belt.

The small pulley is connected to the rear wheel via a one-way clutch, and when the small pulley rotates to the right, the rotation is transmitted to the wheel and the bicycle moves forward.

The bell) 6 is held down from the outside by two idlers 7a and 7b. In order to move the bicycle forward, the crank 5 is rotated in the direction of arrow C, so the dog pulley 2 also rotates clockwise, so the upper side of the belt 6 becomes the tension side (X) and the lower side becomes the slack side (Y). . The idler (A) 7a holds down the belt on the stretching side, and the idler (B) 7b holds down the belt on the slack side.

As shown in FIGS. 3 and 4, the idler (A) 7a is a cylindrical roller that is rotatably supported by a support fitting 9 via a pin 8a. The idler (B) 7b is similarly supported by the lower part of the metal A9, and the sides of the two idlers press the outside of the bell (B) 6, that is, the side without teeth, upward.

Nuts 10a and 10b fix the bottles 8a and ab to the metal fittings 9.

The support fitting 9 has a rotating shaft 11 closer to the large pulley 2 than the two idlers and inside the belt 6.

This shaft 11 fits into a bearing 12 which is welded and fixed onto the pipe-shaped chainstay 1.

13 is a nut and 14 is a cover.

FIG. 1 shows a view taken along line II in FIG. 4.

This figure is a top view of the lower belt.

In this figure, the metal fitting 9 is not parallel to the running direction Q of the belt 6, but is tilted at an angle θ. Therefore, the rotation center N-0 of the idler 7b is also aligned with the axis L-0, which is perpendicular to the belt running direction Q. It is installed at an angle that is rotated by an angle θ relative to M in the running direction Q of the belt.

Next, the operation of this embodiment will be explained.

When a driving force in the C direction is applied to the pedal 4, the upper belt x
Strong tension acts on the belt, and a force acts on the belt so that it approaches a straight line and approaches line F. This force pushes up the idler A7a, rotates the metal fitting 9, rotates the idler B7b attached to the lower side of the metal fitting in the working direction, pushes the lower belt Y upward, and eliminates slack.

At this time, since the metal fitting 9 is not parallel to the running direction Q of the belt 6 and has an angle θ, when the belt moves in the C direction, the upper side of the idler 7b that contacts the belt and rotates in the R direction. Rotate to.

Therefore, the belt traveling in the C direction is constantly subjected to a force in the S direction due to contact with the idler. Therefore, the belt receives force toward the metal fitting 9 and constantly attempts to approach the metal fitting, and does not move to the opposite side and come off the idler 7b.

Effects of the Invention In the present invention, by tilting the metal fitting that supports the idler and rotating the rotation axis of the idler by an angle θ in the running direction of the belt, a force is applied to the belt that constantly tries to move toward the metal fitting, and the belt prevents it from coming off to the opposite side of the metal fittings.

Furthermore, since the metal fittings have a cantilever structure, the belt can be easily removed when replacing the belt, compared to a method in which both sides of the belt are supported by metal fittings to prevent the belt from coming off.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the relationship between the idler support and the belt in an embodiment of the present invention, Fig. 2 is a front view showing the adjustment device, Fig. 3 is a sketch showing the idler support, and Fig. 4 is a diagram showing the relationship between the idler support and the belt in the embodiment of the present invention. It is a sectional view including the rotation axis of a figure. 1...Ten stay, 2...Large pulley, 3...Small pulley, 6...Belt, 7a, 7b...Idler , 9...
Support, 11...rotating shaft, 12...bearing. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 b Figure 4

Claims (1)

[Claims] A large pulley that drives the belt, a belt for power transmission,
and a small pulley driven by a belt, and a device that adjusts the tension of the belt by pressing an idler that is rotatably supported cantilevered by a support against the belt, and that supports the idler. 1. A tension adjustment device for a belt-driven bicycle, characterized in that the rotating shaft of the idler is tilted in the running direction of the belt by tilting the supporting device with respect to the belt.