DECELERATION AND PRESSURE SENSITIVE PROPORTIONING VALVE WITH HIGH PRESSURE DAMPING

A proportioning valve assembly (10, 210) in a housing (12,212) is pressure responsive to control the flow of fluid to a wheel brake cylinder. The proportioning valve (20, 220) is connected to a fluid channel (31, 231) opening into a reservoir (13,213), a second valve (34, 234) being disposed in the channel (31, 231) and being engaged by an inertia sensitive ball (40, 240) located either on a ramp (17) or within a recess (235) of the second valve (234). The ball (40) is responsive to deceleration of the vehicle and moves up the ramp (17), or the ball (240) moves multi-directionally from the recess (235) to be both longitudinal and lateral deceleration responsive. Movement of the ball (40, 240) permits the second valve (34, 234) to close and prevent fluid communication between the fluid reservoir (13, 213) and the proportioning valve (20, 220) in order to vary the outlet pressure of the proportioning valve (20, 220) in response to deceleration or cornering of the vehicle. The proportioning valve (20, 220) includes a second piston (80, 280) which has a plunger end (82, 282) that extends within the channel (31, 231) and a bore (303) of a sleeve (301). The sleeve (301) has an orifice (307) to restrict fluid pressure flow from the bore (30) around the plunger end (282) and through the orifice (107, 307) to the channel (31,231). The sleeve (301), orifice (307), and plunger end (82, 282) provide damping of second piston when sudden high pressure applications occur, and thereby eliminate the occurrence of wheel lock-up.