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EP-4467436-B1 - CONTINUOUSLY VARIABLE TRANSMISSION FOR BICYCLE

EP4467436B1EP 4467436 B1EP4467436 B1EP 4467436B1EP-4467436-B1

Inventors

  • PARK, JEONG SEOK
  • YAN, ZENHUA

Dates

Publication Date
20260506
Application Date
20240108

Claims (6)

  1. A continuously variable transmission for a bicycle, the continuously variable transmission comprising: a shifting part (100) configured to transmit a rotational force of a central shaft (110) to an output shaft (160) while automatically shifting gears in accordance with resistance when rotating by receiving the rotational force of the central shaft (110) through a first carrier (120), first planet gears (130), a first ring gear (140), a first sun gear (150), and the output shaft (160) when a user operates and rotates the central shaft (110); and a load providing part (200) installed to operate in conjunction with the shifting part (100) and configured to selectively provide a load to the shifting part (100), characterized in that the load providing part (200) rotates by receiving a rotational force of a second ring gear (210), which rotates integrally with the first ring gear (140), sequentially through dual planet gears 220), a third ring gear (230), a second sun gear 240), and a generator rotor (250) and provides a load in the reverse order.
  2. The continuously variable transmission of claim 1, wherein a support frame (260) is installed integrally with the first ring gear (140), and the support frame (260) operates in one direction in conjunction with the first carrier (120) through a second clutch (270).
  3. The continuously variable transmission of claim 2, wherein the second clutch (270) has a second latch gear (271) installed on the first carrier (120), and a second latch (273) rotatably installed on an inner surface of the support frame (260) is selectively caught by the second latch gear (271) to selectively rotate the first carrier (120).
  4. The continuously variable transmission of claim 1, wherein the dual planet gears (220) include a second planet gear (221) and a third planet gear (223) installed on a single shaft, the second planet gear (221) engages with an inner portion of the second ring gear (210), and the third planet gear (223) engages with an inner portion of the third ring gear (230) and an outer portion of the second sun gear (240).
  5. The continuously variable transmission of claim 1, wherein the second sun gear (240) engages with an outer portion of the generator rotor (250).
  6. The continuously variable transmission of claim 1, further comprising: a motor part (400) installed to operate in conjunction with the shifting part (100) and configured to provide power to the shifting part (100).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuously variable transmission for a bicycle, and more particularly, to a continuously variable transmission for a bicycle, which is capable of automatically shifting gears steplessly in response to changes in driving power and loads according to traveling environments without a user's manipulation, charging the bicycle with power, which is generated when the bicycle travels or shifts, by an electric generator, preventing a reverse rotation of a central shaft, and enabling the user to manually adjust the gear shifting by using a load providing part as necessary. 2. Description of the Related Art In general, a transmission installed on a bicycle is equipped with multi-stage chain gears having various diameters and respectively mounted on a pedal shaft and a rear wheel shaft. The transmission is configured to shift gears by operating the multi-stage chain gears so that a chain engages with the chain gear with a desired stage. JP 2016 182851 describes a continuously variable transmission for a bicycle which is defined in the preamble of claim 1. However, the transmission using the multi-stage chain gears has a problem in that noise and vibration occur at the time of changing the chain gears for gear shifting, a breakdown rate is high because of frequent withdrawal of the chain, and manufacturing costs are increased. In particular, there is a problem in that stepless gear shifting cannot be performed basically, the user needs to manipulate a gear shift lever to shift gears while driving the bicycle, which increases a risk of a safety accident. In order to solve the problems with the transmission equipped with the multi-stage chain gears, various technologies related to continuously variable transmissions have been proposed. As disclosed in Korean Patent Application Laid-Open No. 10-2012-0080371, the related art, which performs the above-mentioned functions, includes: a shaft rotatably assembled to a boss of a bicycle, having first and second pedal cranks assembled to two opposite sides thereof, and having a first gear disposed at one side of an outer-diameter portion thereof; a one-way unit fastened to and disposed on the boss, having an inner ring for preventing a reverse rotation of an outer ring, and having a second gear provided on an outer-diameter portion of the outer ring; a carrier unit rotatably disposed in an idle state on the shaft and having a third gear installed at one side thereof so as to engage with the first gear, a fourth gear disposed at the other side thereof so as to engage with the third gear, and a fifth gear provided at one side of the fourth gear, integrated with the fourth gear, and configured to engage with the second gear; a drive wheel unit rotatably disposed in an idle state on the shaft and having a sixth gear disposed at one side of a cylinder body and configured to internally engage with the fifth gear, and a seventh gear provided at one side of an outer diameter portion of the cylinder body and connected to a power transmission unit configured to transmit power to a rear wheel of the bicycle; and a control unit installed at one side of the carrier unit and configured to allow the drive wheel unit to control a rotation of the carrier unit in proportion to a traveling resistance force applied to the drive wheel unit. However, the technical configuration in the related art has the following problems. The technology may perform the stepless gear shifting, and the structure of the technology may only perform automatic gear shifting by means of a transmission mechanism, but the structure of the technology cannot perform manual gear shifting. In addition, there is a problem in that the technology has low efficiency because only a user's power is outputted through the transmission mechanism. SUMMARY OF THE INVENTION The present invention has been made in an effort to solve the above-mentioned problems in the related art, and an object of the present invention is to automatically shift gears steplessly in response to changes in driving power and loads according to traveling environments without a user's manipulation, charge the bicycle with power, which is generated when the bicycle travels or shifts, by an electric generator, prevent a reverse rotation of a central shaft, and enable the user to manually adjust the gear shifting by using a load providing part as necessary. Another object of the present invention is to output both power of a user and power of a motor through a transmission mechanism. The objects have been solved by providing a continuously variable transmission for a bicycle the is designed as included in the attached claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a coupled perspective view illustrating a continuously variable transmission for a bicycle of the present invention.FIG. 2 is a cross-sectional view illustrating the continuously variable transmission for a bicycl