Abstract:
A valve portion for a solenoid valve is disclosed. The valve portion includes a valve body including a longitudinal channel, wherein the valve body further includes a supply aperture, a control aperture and an exhaust aperture. A spool is slidably disposed in said longitudinal channel and the spool is adapted to adjust a connection between said supply aperture and said control aperture upon external excitation. A pressure regulation device is operatively connected or adjoined to the exhaust aperture, the control aperture, and the supply aperture, wherein the pressure regulation device is adapted to adjustably connect or adjoin the exhaust aperture to at least one of the control aperture and the supply aperture, such that spool position is generally maintained substantially independent of pressure variation between the control aperture and the supply aperture.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a relief valve, such as a relief valve for a use in connection with a solenoid.  
         [0003]     2. Description of the Related Art  
         [0004]     Spool valve solenoids are known and used in a variety of applications. Among other examples, a spool valve may statically or dynamically control pressure in an environment such as, for example, in connection with an engine valve. The use of a conventional spool valve solenoid as a pressure regulator is known. Typically, spool valves control pressure using at least one magnetic element that, upon excitation, activates a rod and a spool connected thereto to controllably change pressure of a fluid or the like residing in the spool valve. Generally, the spool is slidably disposed in a longitudinal bore defined in a valve body. The movement of the rod and spool provide a mechanism to generally control pressure or movement of a medium passing through portions of the valve body.  
         [0005]     A conventional spool valve arrangement, among other things, can provide a spool that is slidably disposed about a rod such that, as a magnetic element is turned off, the spool may longitudinally slide and generate movement of the rod and armature. This design generally provides a means for controlling the pressure of a medium passing through the valve body independent of an associated magnet. However, this can also lead to a variable air-gap between the armature and a lower portion of the solenoid housing, as the rod and armature position generally change as the pressure exerted upon the spool changes. The variability of the air-gap, therefore, may lead to a variable distance between the armature and a top portion of the solenoid housing. Such variability can also lead to a time variability to fully excite the armature and substantially open the valve body. For at least this reason, improved spool valve solenoids are desired.  
       SUMMARY  
       [0006]     A valve portion for a solenoid valve is disclosed. The valve portion includes a valve body including a longitudinal channel, wherein the valve body further includes a supply aperture, a control aperture and an exhaust aperture. A spool is slidably disposed in said longitudinal channel and the spool is adapted to adjust a connection between said supply aperture and said control aperture upon external excitation. A pressure regulation device is operatively connected or adjoined to the exhaust aperture, the control aperture, and the supply aperture, wherein the pressure regulation device is adapted to adjustably connect or adjoin the exhaust aperture to at least one of the control aperture and the supply aperture, such that spool position is generally maintained substantially independent of pressure variation of fluid between the control aperture and the supply aperture. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]     Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, wherein:  
         [0008]      FIG. 1  is a cross-section view of a valve according to an embodiment of the invention; and  
         [0009]      FIG. 2  is a cross-section view of a valve according to an embodiment of the invention. 
     
    
     DETAILED DESCRIPTION  
       [0010]      FIG. 1  and  FIG. 2  illustrate an exemplary valve  10  in accordance with an embodiment of the invention. Valve  10  is illustrated in an open valve configuration and includes a first portion  12  and a second portion  14 . For convenience, first portion  12  will be referred to as an actuation portion  12 , and second portion  14  will be referred to as a valve portion  14 , however, it will be readily apparent to one skilled in the art that other descriptive terms may also be used to define these portions.  
         [0011]     Actuation portion  12  includes a case  16  and an actuator  17 . Case  16  includes a top portion  18  and a bottom portion  20 . In an embodiment at least a portion of case  16  is a flux collector. Case  16  generally surrounds actuator  17 . It will be appreciated that, actuation portion  12 , actuator  17  and case  16  may be designed in accordance with known arrangements and, thus, actuation portion  12 , actuator  17  and case  16  will only be generally discussed herein. Alternatives to the illustrated arrangement will be recognized by one of ordinary skill in the art and, therefore, they may be used in combination with the present invention, and the present invention should not be limited to the actuation portion illustrated and described.  
         [0012]     In an embodiment, actuator  17  includes a bobbin  28  having an electromagnetic coil  29  operatively wrapped therearound to provide a magnetic coil arrangement. Magnetic coil arrangements to operate solenoid valves are well understood by those skilled in this art and need not be described further herein. A terminal  21  may also be connected to the electromagnetic coil  29  and to ground to generate an electromagnetic force. In an embodiment, the terminal  21  is adapted to receive a signal provided from a control device (not shown). The control device may be internal to the solenoid or part of an external system (not shown).  
         [0013]     Actuator  17  defines a longitudinal channel  23  at a central portion of bobbin  28 . An armature  22  and a rod  24  may be slidably disposed in channel  23  as shown in the Figures. Armature  22  and rod  24  are operatively connected to one another such that movement of armature  22  also provides movement to rod  24  and vice-versa. In an embodiment, a biasing device  25  may also be included between armature  22  and top portion  18  of case  16 . Biasing device  25  generally biases rod  24  and armature  22  toward valve portion  14 . In an embodiment, an adjusting means  26 , such as a screw or the like, may be connected to biasing device  25  to adjustably define a desired amount of force asserted by biasing device  25  between top portion  18  of case  16  and armature  22 , or define a desired compression of biasing device  25 . The benefits and uses of biasing device  25  are known. Among other examples, biasing device  25  may be a coil spring; however, one of ordinary skill will recognize that other biasing devices may also be used.  
         [0014]     As illustrated in the Figures, valve portion  14  is typically arranged adjacent to actuation portion  12 . In an embodiment, valve portion  14  includes a valve body  30  that defines a channel  32  longitudinally extending through a first end  33  and a second end  34  of valve body  30 . First end  33  of valve portion  14  is connected to bottom portion  20  of case  16  of actuation portion  12 . In an embodiment, at least a portion of channel  32  of valve portion  14  is operatively connected or juxtaposed to at least a portion of channel  23  of actuation portion  12  such that channel  32  of valve portion  14  and channel  23  of actuation portion  12  generally interact to form a continuous channel through valve  10 .  
         [0015]     The valve portion  14  includes a spool  36  slidably disposed in channel  32  of valve body  30  and adapts to slidably egress and ingress with respect to channel  23  of actuation portion  12 . In an embodiment, a sealing means  38  may be disposed between rod  24  and spool  36  to seal fluid or the like from entering between case  16  and valve body  30  such that fluid resident in valve portion  14  is generally prohibited from entering actuation portion  12 . In an embodiment, spool  36  and rod  24  are operatively connected through or about sealing means  38 . One of skill in the art will readily recognize a wide variety of types of sealing means  38  may be employed to provide a desired seal between case  16  and valve body  30 . For example, without limitation, sealing means  38  may comprise a diaphragm; however, other sealing means may be employed, such as, for example, an O-ring or the like.  
         [0016]     The valve portion  14  may further include a plug  37  or cap disposed in or about second end  34  of valve body  30 . It should be noted, that plug  37  may be a separate piece or may be integrally formed with valve body  30 . Plug  37  may include an aperture for fluid to enter therein; however, plug  37  may also prohibit fluid from entering into valve body  20 . One of ordinary skill in the art will recognize other alternatives to employing a plug, such as, for example, providing an internal reservoir. Further, second end  34  may be open and allow fluid or the like to enter into valve body  30 . With reference to the Figures, a spool-biasing device  39  may be disposed between plug  37  and spool  36 . In an embodiment, spool-biasing device  39  generally urges spool  36  toward rod  24 . In an embodiment, an adjusting means (not shown) such as a screw or the like, may be connected to spool biasing device  39  to adjustably define a desired amount of force asserted by spool-biasing device  39  between spool  36  and plug  39 , or define a desired compression of spool-biasing device  39 . The benefits and uses of spool-biasing device  39  are known. Among other examples, spool-biasing device  39  may comprise a coil spring; however, one of ordinary skill will recognize that other spool-biasing devices may also be used.  
         [0017]     Case  16  and the actuator  17  are operatively attached to valve portion  14 . Case  16  and valve portion  14  are attached using known attachment means. Among other known arrangements, for example, case  16  may be crimped around a portion of valve portion  14 . One of ordinary skill in the art will recognize various other possible arrangements, for example, case  16  may be heat-formed or heat-staked to valve portion  14  or threadably connected thereto.  
         [0018]     In the illustrated exemplary embodiment, valve body  30  includes at least three apertures  31  at various points along body  30 , including a first aperture  31   a , second aperture  31   b , and third aperture  31   c . In the illustrated embodiment, first aperture  31   a  provides an exhaust path, second aperture  31   b  provides a control path, and third aperture  31   c  provides a supply path. It will be appreciated that various placements, numbers of, or path configurations associated with the apertures are contemplated by the invention, and the invention should not be limited to the specific design illustrated and described. For example, one of ordinary skill in the art may employ a number of other operational arrangements based on various design specifications and/or requirements.  
         [0019]     In a typical arrangement, valve  10  is generally arranged to control hydraulic fluid pressure between exhaust path  31   a , control path  31   b  and supply path  31   c . Valve portion  14  is configured to adjustably define the hydraulic fluid pressure such that the hydraulic flow and, therefore, the amount of hydraulic fluid provided from valve  10  via control path  31   b  may be regulated or controlled.  
         [0020]     With continued reference to the Figures, an embodiment is shown having six exhaust paths  31   a , two control paths  31   b , and two supply paths  31   c . It will be appreciated that an open valve  10  configuration, such as generally illustrated in  FIG. 2 , may be in a coil de-energized condition wherein a biasing device  25  biases or urges armature  22  and rod  24  downwardly until rod  24  has its lower end seated on sealing means  38  generally closing the exhaust apertures  31   a  from the control apertures  31   b  and the supply apertures  36   c . The length of spool  36  may be configured such that as rod  24  is seated on or about sealing means  38 , the spool  36  is positioned so as to partially open supply aperture  31   c  to control aperture  31   b . Thus, in a de-energized condition, an open valve (e.g., as shown in  FIG. 1 ) can provide a reduced pressure flow to control aperture  31   b.    
         [0021]     In an embodiment, spool  36  includes a pressure regulation device  40 . While valve  10  is in an inactive or de-energized state (i.e., actuation portion  12  is not actuated and rod  24  and armature  22  are generally closed) pressure regulation device  40  generally prevents spool  36  from pressing upon or against rod  24  operatively connected thereto. In a conventional arrangement, this pressure would typically urge armature  24  and rod  22  into a semi-active position. For example, within valve body  30 , the hydraulic fluid pressure of the fluid passing between control aperture  31   b  and supply aperture  31   c  often varies due to external factors outside of valve  10 , such as for example, an engine valve requiring different amounts of fluid or the like. Without limitation, the pressure may change due to a change in fluid heat, change in viscosity, or the like. As a result, a pressure variance may be exhibited in connection with spool valve  36 . In other words, in a conventional valve arrangement, as fluid pressure increases in valve portion  14 , pressure is subsequently exhibited upon spool valve  36  slidably residing within channel  32 . Spool  36 , therefore, is urged upward and subsequently impinges upon armature  22  and rod  24 , slidably residing within channel  23  of actuator  17 . This, then, urges at least a portion of armature  22  and rod  24  further upwards into channel  23  of actuator  17  and creates a variable air-gap between bottom portion  20  of case  16  and armature  22  that varies with the hydraulic pressure. As a result, the activation of valve  10  may take a variable amount of time, wherein the time variable is related to or contingent upon a position of rod  24  and the size of the air-gap between armature  22  and bottom portion  20  of case  16 . In demanding environments, even a minimal time variation, such as the variation described, may lead to an unfavorable result. Thus, pressure regulation device  40 , in accordance with the present invention, provides a mechanism to generally minimize, or eliminate, the variable air gap and generally provide a generally constant time-activation to open or close valve  10 .  
         [0022]     With reference to the illustrated embodiment, pressure regulation device  40  includes a shoulder portion  50 , a relief portion  52  and a pressure relief biasing device  54  disposed therebetween. In an embodiment, shoulder portion  50  is attached along a portion of valve body  30  and provides a base for biasing device  54  and relief portion  52 . Relief portion  52  is slidably disposed along channel  32  and operatively connects control path  31   b  with exhaust path  31   a . As the hydraulic pressure in valve body  20  increases along control path  31   b , increased pressure becomes exerted upon relief portion  52 . As generally illustrated in  FIG. 2 , as the pressure exerted upon relief portion traverses beyond or generally reaches a given pressure threshold (which may be prescribed or pre-defined), pressure relief biasing device  54  adapts to generally allow relief portion  52  to become longitudinally displaced (e.g., upwardly) towards shoulder portion  50  such that fluid may egress through exhaust path  31   a  and the pressure may generally remain constant along the control path  31   b . As a result, spool  36  will generally not become longitudinally displaced and the air-gap as described hereinabove will generally remain constant unless the pressure becomes exaggerated beyond a certain level. One of ordinary skill in the art will readily recognize that pressure relief biasing device  54  may be designed to define a pressure threshold and an exaggerated pre-defined level. In this regard, therefore, it will be appreciated that different lengths of shoulder portion  50 , relief portion  52  may be used to provide a pressure relief biasing device suitable for particular design conditions. Similarly, one of ordinary skill will recognize that design considerations and the like will dictate the proper pressure threshold for pressure regulation device  50  and provide a pressure relief biasing device  54  utilizing a compression suitable for such a design.  
         [0023]     Among other examples, pressure relief biasing device  54  may comprise a coil spring; however, one of ordinary skill will recognize that other types or arrangements of biasing devices may also be used.  
         [0024]     With continued reference to the Figures, actuator  17  is, among other possibilities, electronically actuated through terminal  21 . For example, valve  10  is responsive upon the receipt of a first signal sent via an external controller or the like when an increased fluid flow from valve  10  is desired. Conversely, an electrical signal indicating a decrease cause the solenoid spool valve  10  to decrease flow. Further, it should be noted that the present invention may be incorporated into a valve that draws armature toward top portion  16  upon activation of actuation portion  12 , or vice versa. That is, the present invention should not be so limited thereby. Further, the present invention may be incorporated into other types of valves including, among others, bleed valves. These and other features will be appreciated by one of ordinary skill after considering the present disclosure.  
         [0025]     The present invention has been particularly shown and described with reference to the foregoing embodiments, which are merely illustrative of the best modes for carrying out the invention. It should be understood by those skilled in the art that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention without departing from the spirit and scope of the invention as defined in the following claims. It is intended that the following claims define the scope of the invention and that the method and apparatus within the scope of these claims and their equivalents be covered thereby. This description of the invention should be understood to include all novel and non-obvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. Moreover, the foregoing embodiments are illustrative, and no single feature or element is essential to all possible combinations that may be claimed in this or a later application.