Abstract:
A linear three-port actuation valve for a vehicle has a valve seat member that is engaged with a valve body to a location that establishes a desired poppet stroke. The valve body defines a lower seat and the valve seat member defines an upper seat, and a poppet slides within the member to selectively block the lower seat. When the lower seat is not blocked the upper seat is blocked by a ball positioned against the poppet, and vice-versa. Accordingly, the valve seat member aligns the poppet with the lower seat, it aligns the ball with the upper seat, it directs fluid through the upper seat to a control port, and it establishes the desired stroke of the poppet, reducing the number of components and simplifying assembly.

Description:
I. FIELD OF THE INVENTION 
   The present invention relates generally to vehicle actuators. 
   II. BACKGROUND OF THE INVENTION 
   Actuators such as hydraulic valves used in vehicles in anti-lock braking systems (ABS), traction control systems, stability control systems, and other systems typically use electrically-controlled sliding rods to selectively permit or prevent fluid flow through the actuator under particular circumstances, as required for the application. 
   Many such actuators have three ports, with the valve being controlled to establish fluid communication through any two of the ports as dictated by the operational circumstances. Typically, the ports are referred to as the supply, control, and exhaust ports. Such valves can be used to provide actuation hydraulic pressure to other components in the control system by moving the valve to establish fluid communication between the supply and control ports. The actuation pressure subsequently can be relieved by moving the valve to establish fluid communication between the supply and exhaust ports. 
   The present invention recognizes that three port actuation valves usually require the use of many components that must move precisely relative to each other with small tolerances. This burdens both manufacturing and assembly costs, and leads to valves that can be complex to make. The present invention further  recognizes that it would be desirable to provide a linear actuator valve that uses a reduced number of components compared to existing valves, that facilitates alignment of components that must cooperate with each other, and that are simpler to assemble than existing valves. 
   SUMMARY OF THE INVENTION 
   A linear three port actuation valve for a vehicle includes a valve body formed with a supply port, a control port, an exhaust port, and an exhaust valve seat. A valve seat member is in the body, and the valve seat member defines a control valve seat. Also, a poppet defines a head end and a ball end, and the poppet is slidably disposed in the valve seat member for movement between an exhaust configuration, in which the head end is distanced from the exhaust valve seat of the valve body to establish fluid communication from the supply port, through the exhaust valve seat, to the exhaust port, and a control configuration, in which the head end blocks the exhaust valve seat. A ball contacts the ball end of the poppet adjacent the control valve seat of the valve seat member. The ball blocks the control valve seat when the poppet is in the exhaust configuration, and is distanced from the control valve seat when the poppet is in the control configuration to permit fluid communication from the supply port, through the control valve seat, to the control port. 
   If desired, an orifice can be formed in the valve seat member between the control seat and the control port of the valve body. Also, the valve seat member  can be formed with an annular ball retainer above the control seat to prevent lateral movement of the ball. 
   With this structure, the valve seat member not only defines the control seat, but it also aligns the poppet head end with the exhaust valve seat of the valve body. Moreover, the valve seat member directs fluid from the control seat to the control port. Furthermore, the valve seat member can be advanced into the valve body to a location that establishes a desired poppet stroke. Still further, the valve seat member aligns the ball with the control seat. 
   In another aspect, an actuator includes a valve body defining supply, control, and exhaust ports and also defining an exhaust seat. A poppet is movable between a control configuration, wherein the exhaust seat is blocked by the poppet, and an exhaust configuration, wherein the exhaust seat is not blocked by the poppet. Unitary means are provided for slidably supporting the poppet in alignment with the exhaust seat, for defining a control seat, for directing fluid flow from the control seat to the control port, and for laterally supporting a ball above the control seat. 
   In still another aspect, a method for assembling an actuator includes providing a valve body defining supply, control, and exhaust ports and also defining an exhaust seat. The method includes advancing a shaft of a poppet through the exhaust seat until a head of the poppet is juxtaposed with the exhaust seat, and then installing a valve seat member defining a control seat and an orifice extending from the control seat into the valve body over the poppet shaft until the  orifice communicates with the control port of the body. The poppet is aligned with the exhaust seat by the valve seat member. 
   The details of the present invention, both as to its structure and operation, can best be understood in reference to the accompanying drawings, in which like reference numerals refer to like parts, and in which: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The FIGURE is an elevational cross-sectional view of the present actuator in the exhaust configuration, showing associated vehicle components schematically. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Now referring to the FIGURE, an actuator  10  includes a rigid metal or plastic hollow valve body  12  defining a supply port  14 , a control port  16 , and an exhaust port  18 . The body  12  is also formed with a lower annular flange  19  that defines an interior exhaust valve seat  20 . As shown in the FIGURE, the control port  16  may be in fluid communication with a component  22  of a vehicle control system, such as but not limited to an ABS system, a traction control system, a stability control system, or other system. The supply port  14  may receive fluid from a reservoir  24  in the vehicle in which the actuator  10  is located or from some other source, and the exhaust port  18  may exhaust fluid to the reservoir  24  or to some other component. 
   As shown in the FIGURE, a hollow rigid metal or plastic valve seat member  26  is positioned within the valve body  12 . More particularly, the valve seat  member  26  includes an upper flange  28  that engages the bore  30  of the valve body  12  in an interference fit, such that the valve seat member  26  can be engaged with the valve body  12  (by, e.g., a press fit or slip fit with a stake) and held in the location to which it is advanced solely by cooperation of the flange  28  and valve body  12  without the need for further fasteners or engagement methods. In a preferred embodiment the valve seat member  26  is a single unitary piece of plastic or metal. 
   A hollow control seat  32  is formed in the upper flange  28  of the valve seat member  26 . Like the exhaust seat  20  formed by the valve body  12 , the control seat  32  formed by the valve seat member  26  may be frusto-conicafin shape. An orifice  34  is formed in the valve seat member  26  and the orifice  34  communicates with the control seat  32  and with the control port  16 , such that when the control seat  32  is not blocked, fluid may flow through the control seat  32 , orifice  34 , and out of the control port  16 . 
   Above the control seat  32 , the valve seat member  26  forms an annular ball retainer  36  in which a ball  38  may reciprocate along the long axis of the actuator  10  to selectively block the control seat  32 . The ball retainer  36  prevents lateral motion of the ball  38 , such that the ball  38  is aligned with the control seat  32  by the valve seat member  26 . 
   A filter  40  can be installed in the open top end of the valve body  12  as shown. The filter  40  can be slip fit with a stake into the open top end, or it can be press fit, or otherwise engaged with the valve body  12 . The filter  40  may be any filter suitable for removing particles from the fluid entering the actuator  10   through the supply port  14 . A frusto-conical spring retainer  42  protrudes from the filter  40  into the valve body  12  as shown, with a coil spring  44  being snappingly engaged with the retainer  42  to contact the ball  38  and urge the ball  38  toward the control seat  32 . 
   A poppet  46  defining an upward-oriented (looking down on the FIGURE) head end seat element  48 , a ball end  50 , and a shaft  52  therebetween is slidably centrally disposed in the hollow valve seat member  26 . The shaft  52  of the poppet  46  is closely received in the valve seat member  26  as shown, so that the valve seat member  26  aligns the poppet  26  with the exhaust valve seat  20  by preventing lateral motion of the shaft  52 . 
   The head end seat element  48  is formed complementarily to the exhaust seat  20  of the valve body  12 , and the ball end  50  is in contact with the ball  38 . The poppet can move up and down within the valve seat member  26  between an exhaust configuration, in which the head end seat element  48  is distanced from the exhaust valve seat  20  to establish fluid communication from the supply port  14  through the exhaust valve seat  20  to the exhaust port  18 , and a control configuration, in which the head end seat element  48  mates with the exhaust valve seat  20  to block fluid flow through the seat  20 . Under influence of the spring  44 , the ball  38  mates with the control valve seat  32  to block the seat  32  when the poppet  46  is in the exhaust configuration. On the other hand, when the poppet  46  is in the control configuration the ball  38  is pushed away from the control valve seat  32  by the poppet  46  to permit fluid communication from the supply port  14  through the control valve seat  32  and orifice  34 , to the control port  16 .  
   In assembling the valve portion of the actuator  10 , the poppet  46  may be slid upwardly through the exhaust port  20  of the valve body  12  until the head end  48  is adjacent the exhaust port  20  as shown. Then, the ball  38  may be positioned onto the control port  32  of the valve seat member  26  and the valve seat member  26  advanced into the valve body  12  with the shaft  52  of the poppet  46  being received in the valve seat member  26 . The valve seat member  26  is advanced into the valve body  12  until a desired poppet stroke is established. Stated differently, the valve seat member  26  is engaged with the valve body  12  to a location that establishes a desired location of travel of the poppet  46 . The valve seat member may be, e.g., press fitted or slip fitted with a stake into the valve body  12 . Then, the spring  44  may be snapped onto the retainer  42  of the filter  40  and the filter  40  then press fit or otherwise advanced into the valve body  12 , compressing the spring  44  against the ball  38 . 
   With this structure, a single unitary valve seat member of the present invention aligns the poppet with the exhaust seat, it establishes the stroke of the poppet, it aligns the ball with the control seat, and it establishes fluid communication between the control seat and the control port of the body. Only five valving components—the valve body, the valve seat element, the poppet, the ball, and the spring—are required to establish the linear three port actuator of the present invention. 
   Although not central to the inventive valving components discussed above, the FIGURE also shows structure for actuating the poppet  46 . A can  54  can be engaged with the valve body  12  opposite the filter  40 , and a coil  56  is disposed in the can  54 . The coil  56  is electromagnetically coupled to a plunger  58  through a ferromagnetic sleeve  60  to move the sleeve  60  with plunger  58  within the can  54  when the coil  56  is energized and deenergized by control signals from, e.g., an engine control module (ECM) of a vehicle. The plunger  58  abuts the poppet  46  as shown, so that when the plunger  58  moves the poppet  46  also moves. A spring  62  can be provided to bias the sleeve  60  upward relative to the FIGURE and, hence, to bias the actuator  10  to the control configuration when the coil  56  is deenergized. When the coil  56  is energized the actuator  10  is moved to the exhaust configuration.  
   While the particular VEHICLE ACTUATOR as herein shown and described in detail is fully capable of attaining the above-described objects of the invention, it is to be understood that it is the presently preferred embodiment of the present invention and is thus representative of the subject matter which is broadly contemplated by the present invention, that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more”. It is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method  step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. &#39; 112 , sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited as a “step” instead of an “act”. Absent express definitions herein, claim terms are to be given all ordinary and accustomed meanings that are not irreconcilable with the present specification and file history.