Patent GB-1361278-A (GB)
Title: Brakes
IPC: F16D65/78
Filed: 1971-08-18
Abstract: 1361278 Differential braking; brakes on transmission shaft; disc brakes; cooling; fluidpressure systems H KLAUE 18 Aug 1971 [24 Aug 1970 19 July 1971] 38655/71 Headings F2E and F2F A vehicle brake system comprises actuating means including a single application means, a fluid-pressure circuit for wheel brakes in at least some driven and/or non-driven wheels, and another fluid-pressure circuit for at least one brake on a driving shaft in the transmission system, the driving shaft brake being a watercooled disc brake free of self-servo effects; the actuating means causes operation of the driving-shaft brake(s) only in a first mode, the wheel brakes being operated additionally in a second mode. The driving-shaft brake is capable of sustained action and constitutes the service brake. In Fig. 1, two water-cooled sustained-action brakes are accommodated in the rear axle housing, one brake being provided for each driving shaft 13, 14. During braking, axiallyslidable disc 18 attached to shaft 13 is forced by the axially-slidable but otherwise axed ring 19 against ring 20 secured to the axle housing. Such a brake is shown in detail in Figs. 9, 10 (see below). Rings 19 and 20 (and rings 21, 22, of the brake on the other shaft) are fed with water from the radiator 27 of the vehicle's engine by pump 26 along line 25 and branches 25 1 -25 4 ; return is by line 28. On brake actuation by depression of pedal 36, the brakes in the rear axle housing are applied first by pressure oil from cylinder 30 forced along lines 29, 29 1 , 29 2  to cylinders 23 and 24. Only when the tension in spring 37 is overcome are the front wheel disc brakes 31, 32 applied, by cylinder 34. Fig. 8 shows such a brake (see below). Fig. 3 shows an hydraulically-operated system where the sustained-action brake is a watercooled disc brake 55 located between the vehicle's gear-box 48 and driving shaft 49. The cooling circuit (see below) again includes the engine radiator 56. Pressurized oil is fed by pump 73 to three brake control valves 70 to 72 operated respectively by cams 69 1  to 69 3  linked to brake pedal 63. The configuration of the cams ensures that brake 55 is first applied and the pressure raised to full operating value. Thereupon, the front brakes 64, 65, and rear brakes 66 and 67 are applied simultaneously. Brake 55 may be hand-actuated by lever 77 connected to toggle lever 79. In Fig. 6 (not shown) the sustained-action brake is located between the driving shaft and the rear axle housing. It is applied by compressed air controlled by a solenoid valve which is energized during the first part of the movement of the brake pedal. Thereafter the front and rear brakes are applied simultaneously by further movement of the pedal through separate compressed-air circuits which are also separate from that of the sustained-action brake. This brake may additionally be spring-applied to act as a holding brake by release of compressed air from the spring storage cylinder following operation of a hand-controlled valve located in a yet further compressed air line. In Fig. 5 (not shown) the solenoid-operated valve of Fig. 6 and its air circuit are omitted. Instead, the sustained-action brake is applied hydraulically through a compressed-air/hydraulic converter fed through a relief valve from the compressed air line of the rear brakes upstream of a non-return valve in that line. The front brake line also incorporates a non-return valve, the purpose of these valves being to ensure that the sustained-action brake is applied, and maintained applied, first. Fig. 7 shows an anti-lock circuit where the sustained-action brake 55 is stated to be  arranged on the gear-box. Rotary sensors 64 1  to 67 1  pass a signal to an electrical control unit 99 when a first predetermined angular retardation is exceeded, such signal serving to close the hydraulic inlet valve, e.g. 96 4 , 97 4 , 98 4  of the brake involved. When a second predetermined angular retardation is exceeded the appropriate outlet valve 96 5 , 97 5 , 98 5  is opened. Oil from each outlet valve returns via its own (or a shared) line through a check valve to an equalizing tank (e.g. 96 8 , 97 8 , 98 8 ). Three air lines are associated with the brake pedal 95 and lead to three air/ hydraulic converters 96 2  to 98 2 . The hydraulic valves of the sustained-action brake 55 are connected to the electric control lines of both the rear wheel brakes by cables 66 4 , 67 4  so that brake 55 is simultaneously adjusted when the driving wheels lock. A full-face disc brake for a wheel, Fig. 8, has a two-part ribbed housing 101 1 , 101 2  secured to a hub 100 1  rotating on a stub axle 100; brake segments 103 1 , 103 2 , 104 1 , 104 2 , axially slidable relative to a fixed brake carrier 102, are applied to parts 101 1 , 101 2  respectively by an annular piston-and-cylinder assembly 105 2 , 105 1 , supplied with hydraulic fluid at 106. A water-cooled full-face disc brake for a driving shaft, Figs. 9, 10 having a single axiallyslidable rotating disc 120, is applied by axial movement of a brake ring assembly 114, 119 either mechanically, by expanding device 115 and lever 128, Fig. 10, or by an annular hydraulically-operated piston 116. The mechanical actuation, by springs 125, Fig. 10, may be counter-acted by a compressed-air-operated diaphragm 126. Slack-adjustment is provided for by a free wheel 127 and a clamping ring 129 (operating between sheet metal hoods 130, 131) on rod 124. In Fig. 3 the engine radiator 56 is cooled by a fan 58 driven by an electric motor 57. A further electric motor 59, switched on when the brake pedal 63 is actuated, drives a pump 60 which circulates water between radiator 56 and brake 55 via lines 61, 62.