GB1464372A - Hydrokinetic braking systems - Google Patents

Abstract

1464372 Cooled hydrokinetic brakes HAWKER SIDDELEY DYNAMICS Ltd 14 May 1974 [14 Feb 1973 4 April 1974] 7174/73 and 14966/74 Heading F2E A hydrokinetic brake system comprises a brake housing 1, Fig. 1, a rotor working within the housing, a substantially-sealed header tank 6 at a higher level, a comparatively-wide-bore downcomer pipe 8 extending down to an inlet flow control valve 5 for admitting liquid from the header tank 6 to the housing 1 and the rotor, means (e.g. lever 14) for varying the valve setting in accordance with the degree of braking required, a return pipe 10 for leading liquid from the bottom of the housing 1 back to the header tank 6, a non-return valve 9 for admitting liquid from the housing to the return pipe, a heat exchanger 11 in the downcomer pipe or, as shown, in the return pipe 10 for cooling the liquid, a narrow-bore vent pipe 13 extending from the brake rotor in the housing up to the space above the liquid in the header tank, and a valve or variable restrictor 12 in the return pipe 10 (upstream of the heat exchanger when the latter is located in the return pipe). Fig. 2 (not shown) differs from Fig. 1 only in having the heat exchanger in the downcomer pipe 8. In Fig. 3 an exhauster pump 17 is connected at 16, 15 to the housing outlet connection 3 and discharges through a pipe 18 into the header tank 6: the pump may be run only when it is necessary to remove residual liquid from the brake and reduce the pressure therein to a partial vacuum (to reduce high-speed air-drag). With pump 17, a valve 19, linked to valve 5, must be added in vent pipe 13, so that with both valves closed on brake release, pump 17 can perform its intended function. A spring-opened valve 21 in a connection 20 permits thermosyphoning when the brake is off. Either of these two refinements may be omitted. In Fig. 4 (not shown), pipe 20 is wider, valve 21 is replaced by a pump and, to the right of it, a Venturi, pump 17 is replaced by a non-return valve between pipes 16 and 18, and pipe 18 terminates at the Venturi throat. Fig. 5a (not shown) differs from Fig. 1 only in having a thermostatically-controlled valve (see below) in place of restrictor 12 in return pipe 10, and in having the braking-torque-demand lever 14 coupled to an hydraulic or pneumatic actuator controlled by a spool valve or other servo-regulating device forming part of the vehicle primary brake system and operated by a pedal. The thermostatically-controlled valve (Fig. 5b, not shown) has a fixed orifice and an additional annular orifice which provides rapid release of liquid and therefore lessened heat generation above a predetermined temperature. The servo-controlled actuator may be coupled to the conventional hydraulic brake circuit so that when the pressure in brake 1 or the temperature at the thermostatically controlled valve becomes excesssive, the conventional brakes take a greater proportion of the load (Fig. 5c, not shown).