Abstract:
A solenoid actuated valve assembly includes a valve assembly including at least a moveable valving element and a solenoid assembly including an armature. The solenoid assembly is operative to move the armature in response to electrical activation of the solenoid assembly wherein the armature is independently moveable relative to the valving element and the valving element is in tracking engagement with the armature. The valving element is not retained by the solenoid assembly.

Description:
This application is a continuation-in-part of application Ser. No. 09/677,690, filed Oct. 2, 2000 now abandoned. 
    
    
     TECHNICAL FIELD 
     This invention relates to a proportional solenoid and more particularly to a pull type proportional solenoid with high force capabilities. 
     BACKGROUND 
     In a typical solenoid valve assembly, the solenoid sub-assembly has an armature which acts on, or is coupled to, a valve member in the valve subassembly. As is known, movement of the armature is responsive to the magnetic flux generated as a result of the electrical current applied to the electromagnetic windings of the solenoid sub-assembly. Thus linear movement of the armature causes corresponding linear movement of the valve member which controls the flow of fluid through the valve. When the armature of the solenoid is connected firmly to the valve member any misalignment therebetween results in loss of operating efficiency. In many different types of solenoids, the overall force being generated by the solenoid is adversely affected by cavities or other voids which typically house springs or the like. One such arrangement is shown in U.S. Pat. No. 5,513,832, issued May 7, 1996 and is assigned to Lectron Products, Inc. In the subject patent, a spring cavity is disposed within the armature  64  and results in the reluctance increasing thus causing the magnetic flux path to degrade thus lessening the maximum operating force output from the solenoid. 
     The present invention is directed to overcoming one or more of the problems as set forth above. 
     SUMMARY OF THE INVENTION 
     In an aspect of the present invention a solenoid actuated valve assembly includes a valve assembly including at least a moveable valving element; and a solenoid assembly including an armature. The solenoid assembly is operative to move the armature in response to electrical activation of the solenoid assembly wherein the armature is independently moveable relative to the valving element and the valving element is in tracking engagement with the armature. The valving element is not retained by the solenoid assembly. 
     The present invention further provides a method of controlling flow through a valve assembly using an electrically activated solenoid assembly, the method including causing movement of armature along a path defined by the solenoid assembly; causing a valving element within the valve assembly to move in a path defined by the valving assembly in response to the activation of the solenoid assembly, the path defined by the solenoid assembly including all paths except a path in alignment with the path defined by the valving assembly; and urging the valving element in abutment with the solenoid assembly to cause a tracking relationship between the armature and the valving element. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The sole drawing is a diagrammatic representation of a proportionally controlled, solenoid actuated valve assembly incorporating the subject invention. 
    
    
     DETAILED DESCRIPTION 
     Referring to the drawing a proportionally controlled, solenoid actuated valve assembly  10  is illustrated and includes a valve assembly  12  and a pull type solenoid assembly  14 . The valve assembly  12  includes a housing  16  having a bore  18  defined therein. A valving element  20  is selectively, slideably disposed within the bore  18  to control fluid flow between first and second fluid ports  22 , 24 . The valving element  20  is biased in one direction by a spring  26 . 
     The pull type solenoid assembly  14  includes a solenoid housing  28  having a coil core  30  with a bore  32  defined therein adjacent one end of the coil core  30 . An armature  34  is slideably defined within the bore  32 . A bore  36  is defined in one end of the armature  34  adjacent the one end of the coil core  30 . An electrical wire coil assembly  38  encircles the coil core  30  and is selectively connected to a source of electrical energy (not shown) by an electrical line  39 . 
     A spring assembly  40  is disposed adjacent to and in abutment with the one end of the coil core  30 . The spring assembly  40  includes a first retainer member  42 , a second retainer member  44 , a spring  46  disposed therebetween, and a connector member  48  adjustably secured to the second retainer member  44  and extends through the first retainer member  42 . The connector member  48  has a head portion  50  that extends into the bore  36  of the armature  34  and is loosely secured therein by a locking member  52 . During the assembly of the spring assembly  40  to the armature  34 , the connector member  48  is adjusted to maintain a predetermined force on the spring  46  between the first and second retainer members  42 , 44 . 
     The second retainer member  44  has a flat face  54  on the side thereof opposite the side in contact with the spring  46 . When assembled with the valve assembly  12 , the flat face  54  is in direct abutting contact with the end of the valving element that is opposite to the end in contact with the spring  26 . This arrangement permits varying degrees of misalignment between the valving element  20  and the spring assembly  40  thus eliminating any binding therebetween. 
     It is recognized that various arrangements could be utilized without departing from the essence of the subject invention. For instance, the solenoid housing  28  could be a divider member in abutting contact with the housing  16  and the pull type solenoid assembly  14  with the attached spring assembly  40  being disposed within the divider member. 
     As is known, solenoid-operated fluid control devices are used in a wide range of electrically controlled systems for controlling the pressure and/or flow rate of fluid discharged from a source of pressurized fluid or a valve assembly in response to an electrical input signal supplied to a solenoid assembly. In many applications, a valve sub-assembly and a solenoid sub-assembly are integrated into a unitized fluid control device, commonly referred to as a solenoid valve assembly. 
     INDUSTRIAL APPLICABILITY 
     In the operation of the pull type solenoid assembly disclosed in the drawing, the valving element  20  is spring biased by the spring  26  to its flow blocking position in the absence of an electrical signal through the electrical line  39  to the pull type solenoid assembly  14 . With no electrical signal to the pull type solenoid assembly  14 , the armature  34  is maintained at its rightmost position, as viewed in the drawing. The armature is held in the rightmost position by the spring assembly  40 . Likewise, the valving element  20  is maintained at its flow blocking position by the spring assembly  40 , since the valving element  20  is in abutment with the second retainer member  44  of the spring assembly  40 . 
     Upon the introduction of an electrical signal through the electrical line  39  to the pull type solenoid assembly  14 , a magnetic field is established by the electrical wire coil and the coil core  30 . The magnetic field acts against the bias of the spring assembly  40  to urge the armature  34  in a leftward direction as viewed in the drawing. The magnitude of the movement of the armature  34  is proportional to the magnitude of the electrical signal. 
     Due to the connector member  48  being connected to the armature  34 , movement of the armature  34  in the leftward direction also moves the second retainer member  44  in the leftward direction. The valving element  20  follows or “tracks” the movement of the second retainer member  44  since the spring  26  is acting to urge the valving element  20  in the leftward direction. By increasing the electrical signal through the electrical line  39 , the armature  34  is moved further in the leftward direction thus causing the valving element  20  to move further to the left. As the valving element  20  is moved towards the left as viewed in the drawing, the first fluid port  22  is controllably communicated with the second fluid port  24 . The greater the leftward movement of the valving member  20  the greater the degree of communication between the first and second fluid ports. By increasing or decreasing the electrical signal to the pull type solenoid assembly  14 , the communication of the first and second fluid ports  22 , 24  is selectively controlled. 
     In view of the foregoing, it is readily apparent that the structure of the present invention provides a proportionally controlled solenoid actuated valve  10  that eliminates any voids or holes within the pull type solenoid assembly that would detract from the magnetic efficiency thereof. The subject invention also eliminates plugs and/or seals at the end of the solenoid assembly that is normally required and also eliminates any misalignment problems between the valving element and the armature of the solenoid assembly. 
     Other aspects, objects and advantages of this invention can be obtained from a study of the drawings, the disclosure and the appended claims.