A three-gear automatic transmission for electric vehicle with a brushless control-by-wire centrifugal ball arm engagement device, which comprises an input shaft (1Z), an output shaft (2Z), an input gear (1), an input gear of first gear (11), an input gear of second gear (12), a driving gear of first gear (21) and a driving gear of second gear (22);
- said input gear (1) being fixedly mounted on the input shaft (1Z), and normally engaged with the input gear of first gear (11) and the input gear of second gear (12) respectively along its outer circumference;
- the three-gear automatic transmission is characterized in that:
- the three-gear automatic transmission further comprises three brushless control-by-wire centrifugal ball arm engagement devices (10), a brushless electromagnet of first gear (1WT), a brushless electromagnet of second gear (2WT) and a brushless electromagnet of third gear (3WT);
- the brushless control-by-wire centrifugal ball arm engagement device (10) each comprises a thrust pressing disc (10c), a driven inner-spline hub (10d), a control-by-wire driving disc (10g), a preloading spring (10i), a centrifugal ball arm hollow disc (10j), centrifugal ball arm pins (10k), centrifugal ball arms (10l), centrifugal balls (10m), a magnetic conductive force transmitting disk (10q), centrifugal ball sockets (10r) and a drive shaft (10Z);
- the centrifugal ball arm hollow disc (10j) is rotatably supported on the drive shaft (10Z) by a bearing, and is provided with outer-spline grooves of centrifugal ball arm hollow disc (10ja) on the outer circumferential surface of its one end;
- the control-by-wire drive disc (10g) is arranged on the outer-spline grooves of centrifugal ball arm hollow disc (10ja) by its inner-spline grooves;
- the preloading spring (10i) is disposed between the end of the outer-spline grooves of centrifugal ball arm hollow disc (10ja) and the inside end face of the control-by-wire drive disc (10g);
- the control-by-wire drive disc (10g) is provided with a friction driving end face (10ga);
- the centrifugal ball arm hollow disc (10j) is provided with a plurality of centrifugal ball arm holders which are evenly arranged in the circumferential direction at its other end, the centrifugal ball arm holders each having one centrifugal ball aim pin (10k) fixedly mounted thereon;
- the centrifugal ball arm (10l) has one end mounted on the intermediate journal of the centrifugal ball arm pin (10k) by its smooth bearing hole and is rotatable freely around the centrifugal ball arm pin (10k);
- the centrifugal ball arm (10l) has the other end provided with one centrifugal ball socket (10r), in each of which a centrifugal ball (10m) is provided and capable of rolling freely;
- the thrust pressing disc (10c) has one end face being a smooth end surface (10ca), on which the centrifugal ball (10m) each abuts against, and further has outer-spline grooves provided on its outer circumferential surface;
- the outer-spline grooves of the thrust pressing disc (10c) is axially in sliding engagement with the inner-spline grooves of the driven inner-spline hub (10d);
- the magnetic conductive force transmitting disk (10q) is fixedly mounted on the journal of the drive shaft (10Z) by a bearing hole of the center inner hub of magnetic conductive force transmitting disk (10qa);
- the magnetic conductive force transmitting disk (10q) is provided with an outer disc of magnetic conductive force transmitting disk (10qb);
- one brushless control-by-wire centrifugal ball arm engagement device (10), as the power transmission engagement device for the first gear, is provided between the input gear of first gear (11) and the driving gear of first gear (21);
- one end of the drive shaft (10Z) of the brushless control-by-wire centrifugal ball arm engagement device (10) is connected to one end of the input gear of first gear (11);
- said brushless electromagnet of first gear (1WT) being provided between the brushless control-by-wire centrifugal ball arm engagement device (10) and the input gear of first gear (11);
- one brushless control-by-wire centrifugal ball arm engagement device (10), as the power transmission engagement device for the second gear, is provided between the input gear of second gear (12) and the driving gear of second gear (22);
- one end of the drive shaft (10Z) of the brushless control-by-wire centrifugal ball arm engagement device (10) is connected to the input gear of second gear (12);
- said brushless electromagnet of second gear (2WT) being provided between the brushless control-by-wire centrifugal ball arm engagement device (10) and the input gear of second gear (12);
- one brushless control-by-wire centrifugal ball arm engagement device (10), as the power transmission engagement device for the third gear, is provided between the input gear (1) and the output shaft (2Z):
- one end of the drive shaft (10Z) of the brushless control-by-wire centrifugal ball arm engagement device (10) is connected to one end of the input shaft (1Z);
- said brushless electromagnet of third gear (3WT) being provided between the brushless control-by-wire centrifugal ball arm engagement device (10) and the input gear (1);
- the brushless electromagnet of first gear (1WT), the brushless electromagnet of second gear (2WT) and the brushless electromagnet of third gear (3WT) are all fixedly mounted on a transmission housing by a non-magnetic conductive material.