Patent GB-1265274-A (GB)
IPC: F16D57/04
Filed: 1970-03-24
Abstract: 1,265,274. Hydrodynamic retarders; liquid control and cooling. EATON CORP. 24 March, 1970 [14 April, 1969], No. 14266/70. HeadingF2E. A hydrodynamic retarder comprises a bladed stator, a bladed rotor concentric with and radially spaced from the stator and driven in response to rotation of vehicle wheels, controllable blocking means arranged to enter the spacing between the stator and rotor for controlling the amount of energy absorbed, an inlet port connected to the low temperature side of the vehicle engine cooling system and an outlet port connected to the high temperature side of the system so that energy transferred to the liquid from the impeller is dissipated through the engine cooling system. Cooled water from a motor car radiator is taken from the output side of the conventional pump (which returns most of it to the engine) and is introduced at 69, Fig. 8, to the inlet manifold 68 of a hydrodynamic retarder 26, Fig. 4, where it flows inwards through nozzles 67, Fig. 3, between some of the blades 66 of a stator 62, to a working zone 56. The water absorbs kinetic energy from a turbine rotor 53 having blades 59, Fig. 3, which is driven through an idler gear 39 by a gear 47 extending from the transmission housing. The turbine rotor behaves as a pump and the water is forced into a right-hand chamber 72 and a left-hand chamber 71, Fig. 4. It flows from chamber 72 by passageways 73, and from chamber 71 by a slot (76, not shown) into an outlet manifold 75, and thence through an outlet conduit 74 to the " hot feed " of the car radiator for re-circulation. The degree of braking is governed in two ways: by controlling the inflow to inlet conduit 69, and by controlling the flow between stator and rotor by means of a reciprocatable sleeve 98, Fig. 4. Control system.-A butterfly valve 136, Fig. 9, is mounted in inlet conduit 69 for limited pivoting by a differential piston 117, 119 in a control unit 102. The valve is normally kept closed by a spring 128 acting on the piston, and may be opened by compressed air supplied through a line 111 to a chamber 131 on the left of the piston. The sleeve 98, Fig. 4, is secured to a rod 92 extending from a piston 83 urged to the left by a spring 89 and to the right by compressed air admitted at 87. A compressed air source 86, Fig. 8, supplies a manually-operated pressure regulating valve 106 through line 109 and a pressure valve 152 through a line 153. A line 111  connects the outlet of manual valve 106 to the control unit 102 and also governs the action of pressure valve 152 in a manner to be described. Chamber 72 is connected by line 104 to the liquid chamber 123 on the right of portion 117 of the differential piston 117, 119, in control unit 102, so the liquid pressure in chamber 72 assists closing of the butterfly valve. Operation.-Gear 47 is assumed to be continuously operating. Initially, butterfly valve 136 is kept closed by its spring 128, and sleeve 98 is kept in its left-most position fully occupying gap 60 by its spring 89. When handle 107, Fig. 8, is operated, fitting 154 acts on valve 152 to permit compressed air to flow from line 153 via line 87 to piston 83 to move sleeve 98 out of gap 60. As the handle is further operated, the pressure in line 111 rises sufficiently to move piston 117, 119, opening valve 136, to allow fluid to flow at a restricted rate into the retarder 26 through inlet conduit 69. Since the retarder is at all times mechanically connected to the vehicle transmission, energy will be absorbed in an amount roughly proportional to the amount of liquid admitted to the retarder. Continued opening of valve 106 results in a smooth increase to maximum of the retarding torque. However, line 104 connecting turbine chamber 72 to the annular liquid chamber 123 has the effects that at high engine speeds piston 117, 119 can open butterfly valve 136 only to a lesser amount than would be achieved by the air pressure in chamber 131 alone overcoming spring 128, thereby reducing torque, and at low engine speeds the liquid pressure in chamber 123 has little effect, so that improved torque at low speeds is provided.