| 摘要 |
933,370. Hydrodynamic brakes. GENERAL MOTORS CORPORATION. Oct. 20, 1961 [Nov. 3, 1960], No. 37679/61. Class 103 (1). [Also in Groups XXIV, XXVI and XXXI] To prevent dangerous overspeeding of a gas turbine 9 on substantial load reduction due to downhill driving or failure or slow response of the turbine governor, an intermediate shaft 77 of a following change speed epicyclic gear is braked by an hydrodynamic brake 101 when the turbine reaches a predetermined speed above its normal, the brake being filled, so as to be operative, and emptied under the control of signal and control valves 351, 426 actuated by a Pitot tube governor 159 responsive to turbine speed. Gear arrangement.-A two-speed front epicyclic unit providing direct and overdrive in series with a three-speed and reverse rear epicyclic unit is used to provide four forward and two reverse speeds. The Pitot governor 159 comprises an annular can connected to the intermediate shaft 77, and a tube providing pressure in a governor line 216 proportional to intermediate shaft speed. Hydrodynamic brake operation.-When the gas turbine reaches a predetermined speed, pressure in the Pitot governor line 216 leftwardly shifts a spring biased spool 352 in the brake signal valve 351 to connect main line pressure in 194 through a line 354 to the brake control valve 426. In fourth gear, pressure in an overdrive supply line 341 acts on a piston 358 to increase the spring bias of the spool 352, thus leftward shift of the spool occurs at a higher intermediate shaft speed in front unit overdrive than in front unit direct drive, i.e. it occurs at the same engine speed. Pressure in the line 354 moves a spool 427 of the brake valve 426 downwards so that a brake outlet line 429 is connected to a cooler 434, the high brake outlet pressure closing a one-way valve 433, and a brake inlet line 438 is connected both to a feed line 218 and, to supply the brake with cooled oil, to a lubrication line 436 following the cooler. |
