| 摘要 |
A constant mesh parallel shaft gearbox providing a plurality of ratios has its ratio controlled by having, in place of conventional synchronizer assemblies and dog clutches, rotary positive displacement pumps each having one element (4) connected to the gearbox shaft (2) and another (3) connected to a gear (1). With the pump recirculating fluid the gear (1) freewheels on the shaft (2), a valve ring (9) can prevent recirculation and hence lock the gear for rotation with the shaft. Unidirectional rotation of the gear on the shaft in each direction can be obtained passing pump flow through non-return valves 13 or 14. The invention is equally applicable to epicyclic gearboxes and where brake bands, for example, can be replaced by a rotary pump and valve in accordance with the invention. |
