| 摘要 |
1484076 Load responsive brakes ROBERT BOSCH GmbH 21 May 1975 [11 Sept 1974] 21695/75 Heading F2F A load-responsive brake pressure regulator comprises a housing 1 of which a first part 11 contains a double valve 12 having a double closure member 14, an output valve seat 13 whose position in the housing is adjustable, an input valve seat 16 connected to two members 17, 18 responsive in use to brake cylinder pressure and to pressure regulated by the vehicle driver. Such pressures acting to move the seat 16 in opposite directions the member 17 being a piston having a constant effective pressure responsive surface area and the member 18 being an annular diaphragm whose effective pressure responsive surface area is variable and whose inner edge 19 is clamped to the piston and whose outer edge 20 is clamped in the housing of which a second part 26 guides a hollow stem 15 of the valve seat 13 and of which a third part is either of two interchangeable housing parts 32, 43 one 32 of which contains mechanically operable means 34 for engaging the hollow stem 15 of the output valve seat 13 for adjusting, in use, the position of the output valve seat in dependence on vehicle load and the other 43 of which, Fig. 2, contains pressure responsive means 36 for engaging stem 15 to perform a like function. Depending on the loading of the vehicle axle 35 either the lever 34 or the piston 36 is moved to change the position of stem 15 and if braking is then effected pressure medium from brake valve 3 passes into piston 17 by way of open valve 14, 16 and line 7 to the brake cylinder 6. After a certain increase in pressure in the cylinder 6 the back pressure acting on diaphragm 18 causes an upward thrust on piston 17 and closes valve 14, 16 and if the pressure from valve 3 is further increased the prevailing ratio of surface area of piston 17 to effective surface area of the diaphragm 18 is the determining factor for braking pressure applied to cylinder 6. However if the pressure is decreased piston 17 and diaphragm 18 move upwards, member 14 is raised from seat 13 and the output valve 13, 14 is opened to allow exhaustion to atmosphere via the hollow stem 15 and a non-return valve 9. The effective surface area of diaphragm 18 is varied, by means of an arrangement 24 composed of radial fingers and grooves, in dependence on the actual position of the valve seat 13. |
