| 摘要 |
A coolant pump for an internal combustion engine comprises an impeller shaft 15, and a planetary gearing 20 driving the impeller shaft. The planetary gearing comprises a sun gear 21 rotationally fixed to the impeller shaft, at least one planet gear 24 meshing with the sun gear, a planet carrier 22 provided for being driven by the engine, an annulus 23 having a ring gear 28 that meshes with the at least one planet gear, and a braking device 40 for apply a variable braking load to the annulus. A pulley 26, driven by an engine belt 27, may be rotationally fixed to the planet carrier. Preferably, the braking device comprises a friction element 41 and a driving device 42 for tightening the friction element against a rotating surface 29 of the annulus. The driving device may comprise a casing (46, fig.4) containing a material (49, fig.4), such as wax, whose volume changes with temperature, where the fiction element moves in response to the expansion and contraction of the material. Alternatively, the braking device may comprise an electric motor (43, fig.3) driving a pinion (45, fig.3) that meshes with a further ring gear (30, fig.3) of the annulus. |
