Hydraulic pressure variable device, especially to modify the transmission hydraulic pressure transmitted from the main cylinder to the cylinders of the wheel brakes in vehicle hydraulic braking systems (Machine-translation by Google Translate, not legally binding)

摘要

Hydraulic pressure variator device, especially for modifying the hydraulic delivery pressure transmitted from the main cylinder to the brake cylinders of the wheels in hydraulic braking systems of vehicles, whose device is apt to be inserted in said installations in the transmission of said pressure from a main trunk to a communicating secondary trunk with at least one point at which the hydraulic pressure is used as working pressure, the pressure source being included in said main trunk, this pressure variable device belonging to type in which this variation is obtained by acting the hydraulic pressure of sending on one of the front faces of a plunger of two diameters sliding in a cylinder whose inner cavity has two cylindrical walls having diameters substantially corresponding to those of the plunger, and acting the work pressure on a front face of the piston opposite the aforementioned face, having provided elastic fittings capable of preventing the flow of liquid between the inner walls of the cylinder and the periphery of the piston, said front faces of the piston delimiting, inside the cylinder a first chamber connected to the trunk communicating with the aforementioned hydraulic pressure source and a second chamber connected to the communicating trunk with at least one point at which the hydraulic pressure acts as working pressure, with a passage for the liquid between the two chambers and a valve suitable for controlling the flow of the liquid through said passage, this valve normally allowing a free flow of liquid from the first to the second chamber and intercepting said flow when the pressure in said first and second chambers reach a certain value and resume again when the pressure in said cameras ca and below the said determined value, there being also provided a reaction spring disposed in said second chamber and interposed between the piston and the cylinder, said spring being mounted with a preload such that it opposes that of postponement of the piston towards the second chamber, until the pressure transmitted from the pressure source to said first and second chambers does not reach the predicted predetermined value; in the case of application of the device to hydraulic braking systems for vehicles, it corresponds at least to the value of the pressure necessary to obtain the approach of the shoes to the brake drums of the wheels, characterized in that said second chamber (A) is constituted by an annular recess delimited axially inside the cylinder (1) by the annular front face of the compound piston comprised between the two diameters (d1 and d2) of the latter, and by which the passage between the first chambers and second is constituted by the peripheral play between the part of greater diameter of the plunger and the corresponding wall of the inner cavity of the cylinder and in that the elastic lining (6) interposed between said part of greater diameter of the plunger (4) and the wall corresponding to the inner cavity of the cylinder assumes the valve function that controls the flow of the liquid between the first and second chambers, through the aforementioned He passed. (Machine-translation by Google Translate, not legally binding)