Abstract: A crank axle drive structure for a bicycle includes a bottom bracket having inner teeth, a crank axle rotatably mounted in the bottom bracket, at least one drive gear rotatably mounted on the crank axle and meshing with the inner teeth, and a chainwheel fixing seat rotatably mounted on the crank axle and provided with outer teeth meshing with the drive gear. Thus, the inner teeth of the bottom bracket have a tooth number greater than that of the outer teeth of the chainwheel fixing seat, so that the rotation speed of the chainwheel fixing seat is increased, thereby shortening the diameter of the chainwheel so as to perform a pedaling action at the higher rotation speed in an energy saving manner.

Abstract: A treading type vehicle driving device includes a substrate, a first transmission assembly, a second transmission assembly, a treadle structure, a gear assembly and a position limiting plate. The straight-cut gear A can move reciprocally along the trenches of the slant-cut gears C1 and C2 so as to drive the straight-cut gear A to engage with the straight-cut gear B2 of the first transmission assembly (treading forwards), or to engage with the straight-cut gear D of the second transmission assembly 2A (treading backwards). When the pedal is treaded forwards and backwards, the vehicle moves forwards rapidly with less power. The straight-cut gear A will separate from the engagement of the straight-cut gear B2 or straight-cut gear D of transmission assembly since the teeth trench of the slant-cut gears moves on the slant-cut fan gear(forwards is C1 and backwards is C2); thereby, wheels rotate continuously.

Abstract: A treading type vehicle driving device includes a substrate, a first transmission assembly, a second transmission assembly, a treadle structure, a gear assembly and a position limiting plate. The straight-cut gear A can move reciprocally along the trenches of the slant-cut gears C1 and C2 so as to drive the straight-cut gear A to engage with the straight-cut gear B2 of the first transmission assembly (treading forwards), or to engage with the straight-cut gear D of the second transmission assembly 2A (treading backwards). When the pedal is treaded forwards and backwards, the vehicle moves forwards rapidly with less power. The straight-cut gear A will separate from the engagement of the straight-cut gear B2 or straight-cut gear D of transmission assembly since the teeth trench of the slant-cut gears moves on the slant-cut fan gear(forwards is C1 and backwards is C2); thereby, wheels rotate continuously.

Abstract: A treadle-type vehicle body forward drive structure comprised of a base plate, a transmission assembly and a treadle structure installed onto the base plate, a gear assembly enmeshing the transmission assembly to the treadle structure, and a position limiting plate that maintains the position of the drive structure on the base plate, with the extending ends of the transmission assembly follower shaft installed to the wheel hubs of the vehicle body rear wheels. When the treadle rod is tamped slightly downwards, a slant-cut fan gear of the treadle structure causes a slant-cut gear and a straight-cut gear of the gear assembly to synchronously rotate, at which time since the straight-cut gear of the gear assembly is enmeshed with a straight-cut gear of the transmission assembly, they in combination cause the rotation of the follower shaft and, furthermore, the synchronous rotation of the rear wheels. As such, the user is provided riding pleasure and options.