Hydraulic brake control assembly

#1. Field of the Invention

#This invention relates to a hydraulic brake control assembly for automotive vehicles, and more particularly to a brake pressure control assembly responsive to vehicle deceleration.

#2. Description of the Prior Art

#A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

#FIG. 1 is a cross-sectional view partly schematic of the system of the invention;

#FIGS. 2 and 3 are graphical representations of the hydraulic pressure of the valve means show in FIG. 1; and

#Referring now to the drawings, and especially to FIG. 1 thereof, wherein there is shown a conventional tandem master cylinder to be operated by a brake pedal 11 such that pressurized fluid is applied to front wheel brake means 12 via a conduit 13 and to rear wheel brake means 14 via a conduit 15 and a branch conduit 16. The hydraulic pressure in the branch conduit 16 is admitted to a brake pressure control device 17 while the hydraulic pressure in the branch conduit 18 of the conduit 15 is admitted to a hydraulic pressure sensing device 19.

#The pressure sensing device 19 includes a housing having both ends open, a first plug 21 sealingly attached to one of the open ends of the housing 20 and provided with an inlet 22 and an axial passage 23, and a second plug 24 sealingly attached to the other end of the housing 20 and provided with an outlet 25 and an axial passage 26. The housing 20 includes at its inner wall a sloped portion 27, a ball 28 acting as an inertia responsive valve, and a valve passage 29 thereby constituting a so-called G-valve assembly 30. The ball 28 will roll to climb the sloped wall 27 thereby closing the valve passage 29 when vehicle deceleration of a predetermined value is applied regardless of the condition of loading of the vehicle. Within the housing 20 are provided a check valve body 31 provided with a valve member 32 made of rubber material and a passage means 33, and a spring 34 disposed between the second plug 24 and the check valve body 31 for normally urging the latter to the right as viewed in FIG. 1. The valve member 32 is seated on a seat shoulder 35 of the housing 20 when the hydraulic pressure applied through the central passage 29 is smaller than the urging force of the spring 34 thereby interrupting fluid communication between the valve passage 29 and the outlet 25. Any hydraulic pressure from the outlet 25 to the valve passage 29 is, however, free to pass through the passage means 33 and the valve member 32. When the hydraulic pressure from the inlet 22 is great enough to overcome the force of spring 34, such pressure will be admitted to the outlet 25 through an annular gap 36 formed between the valve body 31 and the housing 20. Thus, a check valve assembly 37 is constituted in the housing 20.

#The brake pressure control device 17 includes a housing 40 having both ends open, a first plug 41 sealingly fitted to one open end of the housing 40, and a second plug 42 sealingly fitted to the other open end thereof. The housing 40 is provided with a first inlet 43 fluidically connected to the branch conduit 16. Within the first plug 41 is movably mounted a piston 44 having an enlarged portion 45, a reduced portion 46, and a head 47. An opening 48 is provided on the piston 44 between the enlarged portion 45 and the head portion 47 to communicate with an outlet 49 of the first plug 41 which is in turn connected to the rear brake means 14 via conduit 50. An annular seal member 51 is fixed to the inside wall of the first plug 41 to cooperate with the enlarged portion 45 of the piston 44. A sealing cup 52 is provided for sealingly guiding and supporting the piston 44. A proportioning valve 53 is thus constituted.