초록 ▼

A fluid controller (17) is disclosed for controlling the flow of fluid to a steering cylinder (19). The controller includes a fluid meter (51) and a valving arrangement (49) including a valve spool (65) and a sleeve (67). The valving (49) defines a main fluid path including a main variable flow cont

A fluid controller (17) is disclosed for controlling the flow of fluid to a steering cylinder (19). The controller includes a fluid meter (51) and a valving arrangement (49) including a valve spool (65) and a sleeve (67). The valving (49) defines a main fluid path including a main variable flow control orifice (121), a variable flow control orifice (123), the fluid meter (51), the steering cylinder (19), and a variable flow control orifice (125). In accordance with the invention, the valving (49) defines a dampening fluid path including a variable dampening orifice (133), the dampening fluid path being in parallel with the main fluid path to dampen pressure spikes in the main fluid path. The size of the variable dampening orifice (133), and the flow therethrough, is a function of the relative displacement between the spool (65) and sleeve (67), whereby the timing and amount of the dampening flow and the relationship thereof to the gain curve of the main fluid path can be selected as desired.

대표청구항 ▼

A controller operable to control the flow of fluid from a source of pressurized fluid to a fluid pressure operated device, said controller being of the type including housing means defining an inlet port for connection to the source of pressurized fluid, a return port for connection to a reservoir,

A controller operable to control the flow of fluid from a source of pressurized fluid to a fluid pressure operated device, said controller being of the type including housing means defining an inlet port for connection to the source of pressurized fluid, a return port for connection to a reservoir, and first and second control fluid ports for connection to the fluid pressure operated device; valve means disposed in said housing means and defining a neutral position and a first operating position; said housing means and said valve means cooperating to define a main fluid path communicating between said inlet port and said first control fluid port and between said second control fluid port and said return port when said valve means is in said first operating position; fluid actuated means for imparting follow-up movement to said valve means proportional to the volume of fluid flow through said main fluid path; said main fluid path including a first variable flow control orifice disposed between said inlet port and said first control fluid port, and having its minimum flow area when said valve means is in said neutral position, and an increasing flow area as said valve means is displaced from said neutral position toward said first operating position, said first variable flow control orifice having its maximum flow area when said valve means is moved to its maximum displacement from said neutral position; characterized by: (a) said housing means and said valve means cooperating to define a dampening fluid path in parallel with said main fluid path, said dampening fluid path being in fluid communication with said main fluid path at a first location disposed between said first variable flow control orifice and said first control fluid port, and at a second location disposed downstream of said second control fluid port; (b) said dampening fluid path including a variable dampening orifice operable to dampen the flow of pressurized fluid in said main fluid path to said first control fluid port to thereby cushion the operation of said controller; and (c) said variable dampening orifice begins to open after said first variable flow control orifice begins to open, as said valve means moves from its neutral position to its maximum displacement position.