Patent GB-977826-A (GB)
Title: Improvements in or relating to hydraulic transmission systems
IPC: F16H41/04
Filed: 1961-03-27
Abstract: 977,826. Controlling vehicles. C. VAN DER LELY N.V. March 27, 1961, No. 11148/61. Heading B7H. An hydraulic transmission comprises an hydrodynamic torque converter having an input shaft for connection to the engine and an output shaft for driving the vehicle which also drives means for regulating the speed of the engine whereby the latter is adjusted to keep the speed of the output shaft constant. A diesel engine 1, having a fuel pump 4, also shown again at 4A for clarity, communicating with injectors 7, drives the input shaft 8 of a torque converter comprising a housing 9 having impeller blades 10, a housing 11 having runner blades 12, and reactor blades 14 the output, shaft 13 of which is connected to the differential driving gears 15, 16, 17, 18, 19, 20 of the vehicle. Pumps 24 and 28 supplied from a reservoir 30, are driven from the input and output shafts of the torque converter through shafts 23 and 28 and bevel gears 21, 22 and 25, 26 respectively. The supply lines 32 and 33 of the pumps 24 and 28 are connected to a valve 34 which has a connection 35 to a valve box 36 and a return line 37 to reservoir. In the position as shown in Fig. 1, the pump 24 is connected to the valve box 36 and pump 28 to reservoir. The valve box 36, Fig. 2, has a cylinder separated by a piston 40 into a space 39 connected to the inlet pipe 35 and a space 45 connected to a return line 51 by a line 46 having a spring-loaded non-return valve 47. A further chamber 48 is connected to line 51 by a line 49 having a spring-loaded non-return valve 50 and is sealed from space 45 by a poppet valve 43 acted upon by a spring device 52, 55, 54, the pressure of which is controlled by a handle 57. The spaces 39 and 45 are connected by an orifice 41 providing a pressure drop so that the piston 40 and valve 43 are urged against the spring 55. The valve 43 produces a pressure drop in liquid passing into the chamber 48 and the maximum pressures in chambers 45 and 48 are determined by the valves 47 and 49. The spaces 45 and 48 are connected respectively to the opposite ends of a cylinder 60 containing a piston 62 urged by a spring 65 towards the end connected to space 45 and connected by a rod 63 to the control of the engine fuel pump 4. The fuel pump 4 also comprises an enginedriven shaft 66 upon which is mounted a sleeve 83 urged in one direction by a spring 94 and in the other by a centrifugal governor 71-82 which is connected to a pivoted lever 88 which co-operates with a lug 95 on the shaft 63 to limit the movement thereof and provide an engine speed-control limit. For a given position of control lever 57, a position of equilibrium will obtain whereby the pressure drop across orifice 41 will balance the pressure of spring 55 on valve 43 and a corresponding pressure drop between chambers 45 and 48 will be determined so setting the position of the pump control shaft 63. Should the engine speed rise, the pressure in space 39 will rise, the valve 43 will move to the right, and the pressure in chamber 48 will increase, thereby moving the control shaft 63 to the right and reducing the engine speed until the former conditions obtain. If the engine speed drops, the converse applies. Thus, the engine speed is kept constant. By altering the position of valve 34, the output speed of the fluid coupling device, that is, the vehicle wheel speed, may be kept constant. The device has particular application to an agricultural tractor. Reference is made to the substitution of mechanical regulators for the hydraulic regulators and to a single regulator which could control either the output shaft of the engine or of the torque converter.