JP2008201397A - Crank gear structure of bicycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a pedaling force from being reduced because the position of a pedal is separated from a body center of gravity when pushing the pedal of a bicycle. <P>SOLUTION: In this crank gear structure, a stationary pulley 12 is interlocked with a planetary pulley 13 so as to make a round movement of a pedal in a linear or oval round trajectory. Therefore, the pedal can be pushed at a position closer to the body center of gravity so as to make the pedaling force large. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a crank structure in which the orbital trajectory of a bicycle pedal is elliptical or linear.

  In the conventional crank, as shown by 1 in FIG. 5 and FIG. 6, the pedal position moves away from the center of gravity of the body at the position where the position of the pedal increases the driving force. Become.

  In the conventional crank, at the position where the pedal is stepped on, in FIG. 5, the pedal position where the driving force is maximum is away from the center of gravity of the body, so the stepping force is reduced.

  In order for the treading force to work effectively, the structure should be such that the pedal can be depressed at a position close to the center of gravity of the body.

Means to solve the problem

  In order for the stepping force to work effectively, the structure of the crank gear that forms the orbit of the pedal as shown in 2 of FIG. 5 and FIG. 6 is ideal.

  As shown in FIG. 5-7-8, by making the rotation trajectory of the pedal into a vertically long elliptical trajectory, the driving force is increased by stepping on the pedal closer to the center of gravity of the body.

The invention's effect

  Since the pedal can be stepped closer to the center of gravity of the body than a conventional crank gear, a large driving force is generated.

  The circle of the two-dot chain line and the ellipse shown in FIG. 5 have the same turning radius, but the circumference is the same as that of the ellipse and the circle with a small solid line. Therefore, the ellipse has better motion efficiency than the conventional crank.

BEST MODE FOR CARRYING OUT THE INVENTION

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  FIG. 1 is a cross-sectional view taken along the arrow in FIG. A shaft 20 passing through the center of the pulley 12 fixed to the boss 1 is integrated with a crank wheel 15 and a belt wheel 14 that drives a rear wheel that also serves as the crank. The pulley 12 and the planetary pulley 13 fixed to the boss are interlocked with each other by a belt 18. The diameter of the planetary pulley is 1 with respect to the fixed pulley-2. When the cranks 15 and 14 make one rotation to the left, the rotating arm 16 integrated with the planetary pulley 13 has two rotating arms 16 with respect to the length 1 of the crank 15 that makes one rotation to the right. The elliptical trajectory shown in FIG. 8 is drawn.

  The drawing of FIG. 8 shows the movement of the rotation angle of FIG. 1 by 20 degrees. The broken line represents the crank 15, the solid line represents the rotating arm 16, and the pedal 8 represents 0.

  If the lengths of the crank and the rotating arm are equal, the pedal movement is a linear reciprocating motion.

  FIG. 3 is a cross-sectional view taken along the arrow in FIG. The crank 5 serving as a belt wheel for driving the crank 6 and the rear wheel through the shaft 20 at the center of the gear 2 fixed to the boss 1 is integrated by the shaft 20. The planetary gear 4 and the rotating arm 7 are integrated with each other through the shaft 11 through the shaft 11 through the cranks 6 and 5. The third gear is for transmission of the fixed gear 2 and the planetary gear 4. The comparison of the diameters of the fixed gear 2 and the planetary gear 4 is 2: 1. Therefore, when the cranks 6 and 5 make one left turn, the planetary gear 4 and the rotating arm 6 make one turn to the right. The contrast between the length of the crank and the length of the rotary arm is 2 to 1, so the pedal movement is as shown in FIG.

  FIG. 7 shows the movement of the crank gear of FIG. The cranks 6 and 5 are indicated by broken lines, the rotary arm 7 is indicated by a solid line, and the pedal is indicated by 0.

  It is sectional drawing seen from the plane of the arrow direction of FIG.   The fixed pulley and planetary pulley are linked by a belt in the side view seen from the left side.   It is sectional drawing from the plane of FIG.   The movement is the same as Fig. 2 using gears instead of belts or chains.   Representing the difference in the length of circular orbit and circular orbit   A representation of the difference in strength at the stepping position   Figure 3-4 shows the movement of the crank, rotating arm and pedal   The direction of movement of the crank, rotating arm and pedal in Fig. 1-2

Explanation of symbols

1 Boss 2 Fixed Gear 3 Transmission Gear 4 Planetary Gear 5 Belt Wheel 6 Crank 7 Rotating Arm 8 Pedal 10 Transmission Gear Shaft 11 Shaft Integrating Planetary Gear and Rotating Arm 12 Pulley Fixed to Boss
13 Planetary pulley
14 Belt wheel 15 Crank 16 Rotating arm 17 Shaft 18 integrating planetary pulley and rotating arm 18 Belt 19 Belt 20 transmitting to rear wheel Center shaft

Claims (3)

  The planetary gear through the transmission gear to the gear fixed to the boss rotates around the fixed gear together with the crank. At this time, the diameter of the planetary gear is 1 while the diameter of the fixed gear is 2. Therefore, when the crank rotates once to the left, the planetary gear and the rotating arm integrated with the planetary gear rotate to the right, so that the orbit of the pedal becomes elliptical or linear reciprocating motion.   By changing the length of the crank and the rotating arm, the orbit and direction of the pedal can be changed.   Belt car and chain ring can also be used as a crank

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