Hydraulic automatic transmission bicycle

A hydraulic automatic transmission comprising:

• at least one hydraulic motor including a motor driving axis;
• at least one hydraulic pump including a pump driving axis, capable of pressurizing fluid contained in said pump, and capable of discharging said pressurized fluid to said hydraulic motor;
• and
• at least one shift adjustor,
• wherein a motor pressure is a pressure of said fluid contained in said hydraulic motor, and wherein said hydraulic motor pressurizes said fluid contained in said hydraulic motor to a motor pressure while increasing and decreasing said motor pressure as an external mechanical load exerted onto said hydraulic motor respectively increases and decreases;
• wherein a pump pressure is a pressure of said fluid contained in said at least one hydraulic pump, wherein said at least one hydraulic pump pressurizes said fluid contained in said at least one hydraulic pump using mechanical energy supplied thereto to a pump pressure which is higher than said motor pressure, and discharges a pump discharging volume of said fluid to said hydraulic motor, and wherein said pump discharging volume decreases and increases as said external mechanical load increases and decreases, respectively, whereby said hydraulic automatic transmission automatically changes gear ratios in response to changes in said external load and in response to changes in said pump discharging volume which is caused by said changes in said external load, wherein said gear ratios are ratios of a number of rotations of said pump driving axis to a number of rotations of said motor driving axis;
• and
• at least one shift adjustor which manipulates at least one of a maximum external load at which said gear ratios change, a minimum external mechanical load at which said gear ratios change, a maximum motor pressure at which said gear ratios change, and a minimum motor pressure at which said gear ratios change.

A bicycle including a front wheel, a rear wheel, a pedal, and a hydraulic automatic transmission for automatically changing gear ratios in response to an external mechanical load exerted onto said bicycle, wherein said pedal operationally couples with said front wheel and delivers mechanical energy to said front wheel when a user rotates said pedal by supplying said mechanical energy to said pedal comprising:

• at least one hydraulic motor;
• at least one hydraulic pump capable of pressurizing fluid contained therein and capable of discharging said pressurized fluid to said hydraulic motor;
• and
• at least one control unit,
• wherein said hydraulic motor includes a motor driving axis mechanically coupled to said rear wheel, and generates mechanical power to rotate said motor driving axis and said rear wheel using said pressurized fluid delivered to said hydraulic motor by said at least one hydraulic pump, wherein a motor pressure is a pressure of said fluid contained in said hydraulic motor, and wherein said hydraulic motor increases or decreases said motor pressure as external mechanical load exerted onto said bicycle respectively increases or decreases,
• wherein said at least one hydraulic pump includes a pump driving axis and defines a pump driving volume, discharges a pump discharging volume of said pressurized fluid to said hydraulic motor per a rotation of said pump driving axis, while pressurizing said fluid contained in said pump to a pump pressure which is higher than said motor pressure using said mechanical energy,
• wherein said at least one hydraulic pump changes said pump discharging volume in response to changes in said mechanical load, whereby a ratio of a first number of rotations of said front wheel to a second number of rotations of said rear wheel automatically changes in response to said mechanical load, and
• wherein said control unit is capable of manipulating said pump driving volume in response to changes in said mechanical load and, therefore, capable of manipulating said ratio of said first number to said second number by manipulating at least one of said pump pressure at which said pump discharging volume changes, said motor pressure at which said pump discharging volume changes, and said mechanical load at which said pump discharging volume changes.