A variable speed transmission for electric car, comprising:
- a dynamic power source;
- a mainshaft operatively connected to the dynamic source;
- a transmission housing;
- an auxiliary axle housing
- in which power from the mainshaft is transmitted to a plurality of different pairs of gears in the transmission housing, each pair of gears comprising a driving gear and a driven gear that are meshed with each other, the number of gear teeth of this driving gear is increasing from a primary driving gear and decreasing to a final driven gear, the primary driving gear being directly attached to and rotated synchronously with the mainshaft while the rest of the driving gears have individual extension housings interlocked to the mainshaft from an inner end to an outer end in an alternating order such that the mainshaft cannot directly transmit its power to these driving gears, the final driven gear being directly attached to the auxiliary axle housing thus the two such that they can rotate synchronously, the driven gears having individual extension housings interlocked to an exterior of the auxiliary axle housing from an outer end to an inner end in an alternating order such that the driven gears can rotate the auxiliary axle housing
- only when the mainshaft is rotating in a forward direction by transmitting its power to a one-way spiral spring of a second driven gear and the rest of the gears, one-way spiral spring of the driving gears installed between the extension housing of the second main gear and the main shaft, and between two adjacent extension housings of the driving gears, each spiral spring of the driving gears being interlocked to the extension housing of the next higher driving gear such that each pair can rotate synchronously, whereby each spiral spring of a driving gear may be compressed against the mainshaft and extension housing of a lower driving gear thereby enabling the driving gear to be rotated by the mainshaft;
- further one-way spiral springs installed between adjacent extension housings of the driven gears and between the extension housing of the next to the last driven gear and the auxiliary axle housing, Such that each of the further one-way spiral springs transmits its power to the auxiliary housing when the mainshaft is rotating in a forward direction, whereby the further spiral spring allows an extension housing of a lower driven gear to rotate at a lower speed than an extension housing of a higher driven gear;
- a reverse gear driven assembly directly attached to the auxiliary axle housing so as to rotate synchronously with the auxiliary axle housing;
- a reverse gear spiral spring installed between an extension housing of the primary driven gear and the reverse gear driven assembly, whereby the reverse gear spiral spring can transmit power on the extension housing of the primary driven gear to the reverse gear assembly when the mainshaft is rotating in a reverse direction;
- and
- a plurality of automatic gravity type shifting assemblies installed in the extension housings of the driving gears, each automatic gravity type shifting assembly interlocking with a one-way spiral spring of the driving gear by a driven shifting part, such that centrifugal action the shifting part to shift from a holding position when the auxiliary axle housing rotational speed is less than a pro-set limit of the automatic gravity type shifting assembly, whereby the shifting part does not interlock with a spiral spring of the driving gear and thus it cannot directly be driven by the mainshaft to a driving position in which the spiral spring of the driving gear is compressed inward towards one of the mainshaft and the extension housing of a lower gear and then rotated synchronously when the shifting part is shifted to a position whereby in gear, and power is transmitted ,from the mainshaft to the extension housing of the higher gear, thus the mainshaft and the auxiliary axle housing will have a variable speed ratio.