Electric powered bicycle

Abstract

An electric powered bicycle having a dip sensor or switch and/or a gradient sensor or switch. The bicycle has front and rear wheels each rotatably supported by a frame; a chain slung between the wheels and a chainset for transferring manual power to the wheels; an electric motor coupled to one of the wheels for driving the wheel directly; and a power supply capable of supplying electric power to the motor. The dip gradient sensors are associated with a pulse width modulation circuit.

I claim:  
     
       1. An electric powered bicycle comprising: 
       front and rear wheels rotatably supported by a frame of the bicycle;  
       a chain for transferring a manual power to one of said wheels via a pedal;  
       a DC motor for driving said rear wheel to provide an auxiliary power source;  
       a power supply capable of supplying voltage to said DC motor;  
       gradient means for determining the angle of the bicycle relative to a horizontal plane mounted on said frame and activated when said frame is inclined relative to a horizontal line; and  
       a control circuit for controlling the voltage supplied to said DC motor from said power supply based on a signal from said gradient means, said control circuit comprising:  
       a power transistor for controlling the voltage supplied to said DC motor;  
       a detection transistor for detecting an induced voltage generated between brushes of said DC motor upon the rotation of said bicycle to turn on said power transistor; and  
       a pulse generator for periodically turning off said detection transistor, said gradient sensor being activated to turn off said detection transistor when the gradient of said frame exceeds a predetermined level.  
     
     
       2. An electric powered bicycle according to claim  1 , in which a switch for detecting a dip of said chain is provided on said frame, said control circuit being actuated by turning on said switch that detects the tension of said chain. 
     
     
       3. An electric powered bicycle according to claim  2 , wherein said gradient means for determining the angle of the bicycle includes a gradient sensor for producing an analog gradient signal corresponding to an ascent angle of a road on which the bicycle is travelling and further comprising a PWM control circuit for controlling the voltage supplied to said motor from said power supply based on said analog signal from said gradient sensor. 
     
     
       4. An electric powered bicycle, comprising: 
       
         front and rear wheels rotatably supported by a frame of the bicycle;  
       
       
         an electronic motorized tire drive mechanism for driving at least one of said wheels to provide a power source therefor;  
       
       
         a power supply capable of supplying voltage to said electric motorized tire drive mechanism;  
       
       
         gradient means mounted on said frame and activated when said frame is inclined relative to a horizontal line; and  
       
       
         a control circuit for controlling the voltage supplied to said motor from said power supply based on a signal from said gradient means, said control circuit comprising:  
       
       
         a power transistor for controlling the voltage supplied to said motor;  
       
       
         a detection transistor for detecting an induced voltage generated between brushes of said motor upon the rotation of said bicycle wheel to turn on said power transistor; and  
       
       
         a pulse generator for periodically turning off said detection transistor,  
       
       
         said gradient sensor being activated to turn off said detection transistor when the gradient of said frame exceeds a predetermined level.  
       
     
     
       5. An electric powered bicycle according to claim  4 , further comprising: 
       
         a pair of pedals for engaging a user's feet; and  
       
       
         a manual tire drive mechanism for transferring manual power from said pedals to at least one of said wheels.  
       
     
     
       6. An electric powered bicycle according to claim  5 , in which said manual tire drive means comprises a chain; 
       
         and wherein said bicycle further comprises, attached to said frame, a switch for detecting a decrease in tension of said chain;  
       
       
         wherein said control circuit is activated by said switch.  
       
     
     
       7. An electric powered bicycle according to claim  5 , wherein said manual tire drive means comprises a chain, and 
       
         said bicycle further comprising, attached to said frame, a switch for detecting a decrease in tension of said chain, wherein said control circuit is activated by said switch.  
       
     
     
       8. An electric powered bicycle according to claim  4 , 
       
         wherein said gradient means includes a gradient sensor for producing a gradient signal corresponding to an ascent angle of a road on which said bicycle is traveling,  
       
       
         and further comprising a PWM control circuit for controlling, as a function of the gradient signal, the voltage being supplied to said motor from said power supply.  
       
     
     
       9. An electric powered bicycle according to claim  4 , wherein said gradient means includes a gradient sensor for producing a gradient signal corresponding to an ascent angle of a road on which said bicycle is traveling, and 
       
         further comprising a PWM control circuit for controlling, as a function of the gradient signal, the voltage being supplied to said motor from said power supply.  
       
     
     
       10. In a bicycle having a frame, front and rear wheels rotatably mounted on said frame, pedals, and a manual tire drive mechanism for transferring mechanical power from the pedals to at least one of said wheels, the improvement comprising: 
       
         an electric motorized tire drive mechanism for driving said wheel driven by said manual tire drive mechanism to provide an auxiliary power source therefor;  
       
       
         a power supply capable of supplying voltage to said electric motorized tire drive mechanism;  
       
       
         gradient means for determining the angle of the bicycle mounted on said frame and activated when said frame is inclined relative to a horizontal line; and  
       
       
         a control circuit for controlling the voltage supplied to said motorized drive mechanism from said power supply based on a signal from said gradient means, said control circuit comprising:  
       
       
         a power transistor for controlling the voltage supplied to said motor;  
       
       
         a detection transistor for detecting an induced voltage generated between brushes of said motor upon the rotation of said bicycle wheel to turn on said power transistor; and  
       
       
         a pulse generator for periodically turning off said detection transistor,  
       
       
         said gradient sensor being activated to turn off said detection transistor when the gradient of said frame exceeds a predetermined level.