| 摘要 |
<p>1,148,557. Pressure-modifying valves. SOC. ANON. D.B.A. 13 July, 1967 [30 July, 1966], No. 32206/67. Headings F2F and F2V. A pressure-modifying device in an hydraulic braking system for vehicles comprises a resilient metallic diaphragm containing an opening forming a valve seat co-operating with a movable valve member attached to a control element responsive to the outlet pressure and resiliently maintained in a position which keeps the valve open. In Fig. 1 pressure from a master cylinder (not shown) is applied at 20 to a chamber 38 which communicates via opening 32 and chamber 40 with lines 22 and 24 connected to the brake cylinders. When the pressure in chamber 40 reaches a predetermined value, a resilient metal disc 34 moves to the right and via a stem 44 moves a valve 46 to close the aperture 32 in a further resilient metallic diaphragm 30. On further increase in pressure, the diaphragm 30 moves slightly to the right to open the valve again, so that the pressure in chamber 40 rises somewhat, but at a lower rate than the rise in chamber 38. The resiliency of the diaphragm 30 should be less than that of the disc 34, and the operational characteristics may be altered by changing the thickness and resiliency of these. The port 28 may be connected to a source of variable pressure representing, e.g. axle loading, to modify the braking effect thereby. The signal representing axle loading may alternatively be introduced by a linkage and push rod acting directly on the disc 34 (Fig. 2, not shown). In another modification (Fig. 3, not shown) the disc 34 is rigid and the stern 44 is attached to it via flexible bellows or a barometric capsule. In this case the disc 34 has apertures so that the port 28 leads to the braking cylinders, lines 22 and 24 being omitted.</p> |
