Pedaling sensing device of electric bicycle

Abstract

A pedaling sensing device of an electric bicycle is configured to connect to a motor and includes a crank axle, a first gearwheel disposed around the crank axle, a second gearwheel disposed around the first gearwheel, a sensing unit, an assisting unit, and a chain wheel. The crank axle has first bevel teeth, and the first gearwheel has a first transmission structure and second bevel teeth matching the first bevel teeth. The second gearwheel has a second transmission structure matching the first transmission structure. When the crank axle is driven by a force to rotate, the first gearwheel, second gearwheel and chain wheel are carried to rotate. The first gearwheel also moves with respect to the crank axle along the axial direction, so the sensing unit can sense the applied force. Then, the motor drives the assisting gearwheel and chain wheel to rotate, thereby achieving assisting riding effect.

What is claimed is: 
     
         1 . A pedaling sensing device of an electric bicycle, which is configured to connect to a motor of the electric bicycle, comprising:
 a crank axle extending along an axial direction and comprising an outer surface, wherein a plurality of first bevel teeth are disposed around the outer surface;   a first gearwheel disposed around the outer surface of the crank axle and comprising a first inner annulus surface and a first outer annulus surface, wherein the first inner annulus surface is formed with a plurality of second bevel teeth matching the first bevel teeth, and the first outer annulus surface is formed with a first transmission structure;   a second gearwheel disposed around the first outer annulus surface of the first gearwheel, wherein the second gearwheel comprises a second inner annulus surface disposed around the first outer annulus surface, and the second inner annulus surface is formed with a second transmission structure matching the first transmission structure;   a sensing unit disposed around the crank axle and located adjacent to the first gearwheel, wherein the sensing unit is signally connected with the motor;   an assisting unit comprising an assisting gearwheel disposed around the crank axle, wherein the motor is configured to drive the assisting gearwheel to rotate; and   a chain wheel disposed around the crank axle and connecting to the assisting unit.   
     
     
         2 . The pedaling sensing device according to  claim 1 , wherein when a force is applied to rotate the crank axle, the first gearwheel, the second gearwheel and the chain wheel are carried to rotate, the first gearwheel also moves with respect to the crank axle along the axial direction while rotating, such that the sensing unit senses the applied force so as to control the motor to drive the assisting gearwheel to rotate, and the assisting unit transmits an assisting power from the motor to the chain wheel for assisting to rotate the chain wheel. 
     
     
         3 . The pedaling sensing device according to  claim 1 , wherein the assisting unit further comprises a connecting base disposed around the crank axle, the connecting base is located between the crank axle and the assisting gearwheel and connected to the chain wheel, and the connecting base carries the chain wheel to rotate as the assisting gearwheel rotates. 
     
     
         4 . The pedaling sensing device according to  claim 3 , wherein the assisting unit further comprises a one-way bearing disposed around the connecting base, the one-way bearing is located between the connecting base and the assisting gearwheel, and the one-way bearing drives the assisting gearwheel to rotate so as to carry the connecting base to rotate in one way. 
     
     
         5 . The pedaling sensing device according to  claim 2 , wherein the sensing unit further comprises a pressure sensing element disposed around the crank axle, and the first gearwheel moves toward the pressure sensing element as the first gearwheel rotates along with the crank axle, thereby increasing a pressing force applied to the pressure sensing element, so that the sensing unit senses the applied force. 
     
     
         6 . The pedaling sensing device according to  claim 5 , further comprising a thrust bearing disposed around the crank axle, wherein the thrust bearing is located between the first gearwheel and the pressure sensing element. 
     
     
         7 . The pedaling sensing device according to  claim 6 , further comprising an elastic element disposed around the crank axle, wherein the elastic element is located at one side of the first gearwheel away from the thrust bearing, and the elastic element pushes the first gearwheel toward the thrust bearing. 
     
     
         8 . The pedaling sensing device according to  claim 7 , wherein the elastic element is a disc spring. 
     
     
         9 . The pedaling sensing device according to  claim 2 , wherein the sensing unit comprises a magnet disposed on the first gearwheel and a magnetic sensing element, the magnetic sensing element is disposed adjacent to the crank axle for sensing a magnetic flux variation, and the magnet rotates and moves along the axial direction as the first gearwheel rotates along with the crank axle, such that the magnetic sensing element senses the magnetic flux variation so as to sense the applied force. 
     
     
         10 . The pedaling sensing device according to  claim 9 , wherein the first gearwheel is located between the magnetic sensing element and the assisting gearwheel, and the first gearwheel moves toward the assisting gearwheel along the axial direction as the first gearwheel rotates along with the crank axle. 
     
     
         11 . The pedaling sensing device according to  claim 10 , further comprising an elastic element disposed around the crank axle, wherein the elastic element is located between the first gearwheel and the assisting gearwheel, and the elastic element pushes the first gearwheel toward the magnetic sensing element. 
     
     
         12 . The pedaling sensing device according to  claim 11 , wherein the elastic element is a disc spring. 
     
     
         13 . The pedaling sensing device according to  claim 1 , wherein at least one bearing is disposed adjacent to the second gearwheel. 
     
     
         14 . The pedaling sensing device according to  claim 1 , wherein the first transmission structure comprises a plurality of straight teeth. 
     
     
         15 . The pedaling sensing device according to  claim 1 , wherein the first transmission structure comprises a plurality of bevel teeth. 
     
     
         16 . The pedaling sensing device according to  claim 1 , wherein the first transmission structure comprises a plurality of wavy teeth. 
     
     
         17 . The pedaling sensing device according to  claim 1 , wherein each of two ends of the crank axle is connected to a crank, and the crank is further connected to a pedal. 
     
     
         18 . The pedaling sensing device according to  claim 1 , wherein the first gearwheel comprises a main body portion and a ring portion disposed at one end of the main body portion. 
     
     
         19 . The pedaling sensing device according to  claim 18 , wherein the main body portion and the ring portion are integrated as one piece. 
     
     
         20 . The pedaling sensing device according to  claim 1 , wherein the first gearwheel comprises a main body portion.