Patent Publication Number: US-2011057132-A1

Title: Solenoid valve

Description:
TECHNICAL FIELD 
     This disclosure relates to solenoid valves for selectively varying fluid flow. 
     BACKGROUND OF THE INVENTION 
     Solenoids are devices that convert electrical current into linear motion. A coil within the solenoid converts electrical energy into a magnetic field. The solenoid may therefore convert electrical energy into mechanical energy which moves a magnetically-responsive armature. The armature, in turn, mechanically moves the valve to shut off, release, dose, distribute, regulate, or mix fluids. Solenoid valves may directly control fluid systems flowing through the valve orifice or may be used to control flow through a larger orifice. 
     SUMMARY 
     A solenoid valve includes an armature portion, a spool portion, and a housing. A piloting feature is operatively connected to the housing and configured to align and guide the armature portion. A stator is disposed with respect to the housing and has a selectively energizable coil disposed annularly about the armature portion. The stator is configured to selectively subject the armature portion to a stator force and the armature portion is linearly moveable within the stator. A return spring is configured to provide a return force generally opposite the stator force. 
     The stator of the solenoid valve may be configured such that the stator force pulls the armature portion toward the stator, and the return spring configured to push the armature portion away from the stator. The armature portion may include a first mating feature and the spool portion a second mating feature, such that the armature portion and the spool portion are separate components which are operatively connected by the first and second mating features. 
     The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes and other embodiments for carrying out the invention when taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic, cross-sectional view of a pull-style solenoid valve; 
         FIG. 2  is a schematic, cross-sectional view of a pull-style solenoid valve having combined armature and spool portions; and 
         FIG. 3  is a schematic, cross-sectional view of a push-style solenoid valve having combined armature and spool portions. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to the drawings, wherein like reference numbers correspond to like or similar components throughout the several figures, there is shown in  FIG. 1  a schematic, cross-sectional view of a solenoid valve  10 . A housing  12  has a stator  14  statically disposed or mounted with respect to the housing  12 . 
     The stator  14  includes a selectively energizable coil  16 . Passing a current through the conductor material of the coil  16  establishes or generates a magnetic field within the coil  16 . Magnetic materials located within the stator  14  would therefore direct the magnetic flux to the desired location when the coil  16  is selectively energized with such a current. In the view shown in  FIG. 1 , the magnetic field may impose either a rightward or leftward force on the armature portion  20 , depending on the direction of the current through the coil  16 .  FIG. 1  schematically illustrates a resulting magnetic force as stator force  18 , which is in the leftward direction. 
     An armature portion  20  is disposed annularly within the stator  14 , and is therefore subject to the stator force  18  selectively created by the coil  16 . The armature portion  20  is linearly moveable (to the left or right, as viewed in  FIG. 1 ) within the stator  14 . 
     The armature portion  20  is operatively connected (as described in more detail herein) to a spool portion  22 , which is movably disposed within a valve body  26 . As the armature portion  20  moves relative to the stator  14 , the spool portion  22  therefore moves a substantially equal distance within the valve body  26 . As the spool portion  22  moves within the valve body  26 , operation of the solenoid valve  10  changes by variably blocking and opening fluid passages. 
     The valve body  26  may be attached by (for example, and without limitation) bolting, crimping, welding, or otherwise securing the valve directly to the housing  12 . Alternatively, both the housing  12  and valve body  26  may be fixedly secured to other static structure, such that the stator  14  remains fixed with respect to the valve body  26 . 
     The armature portion  20  is formed from a magnetic material capable of actuation by the magnetic field established by coil  16 . The spool portion  22  may be formed from either a magnetic or nonmagnetic material suitable for use within valves, as would be recognized by those having ordinary skill in the art. 
     A return spring  24  is configured to provide a return force generally opposite the stator force  18 . Therefore, as shown in  FIG. 1 , the return spring  24  is disposed between the housing  12  and spool portion  22 , and is configured to bias the spool portion  22  to the right. When coil  16  is not energized, the return spring  24  moves the spool portion  22  to the right, which establishes the default position of solenoid valve  10 . The default position may represent either an on, off, or partial-flow state for the solenoid valve  10 . 
     In  FIG. 1 , much of the armature portion  20  is shown within the housing  12 , and may, therefore, represent the leftward boundary of the range of movement available to armature portion  20 . The position shown in  FIG. 1  occurs when the coil  16  is energized and is pulling the armature portion  20  into the housing  12 . Those having ordinary skill in the art will recognize that leftward movement of the armature portion  20  causes the return spring  24  to be compressed, which increases the magnitude of the return force acting upon the spool portion  22 . 
     The solenoid valve  10  shown in  FIG. 1  (and also those shown in  FIGS. 2 and 3 ) may not be drawn to scale, and those having ordinary skill in the art will recognize that the gap between the exterior of the armature portion  20  and interior of the stator  14  may be smaller and may vary in geometry from what is shown in  FIG. 1 . Because the stator  14  shown in  FIG. 1  is configured to produce the leftward stator force  18 , the armature portion  20  is pulled toward, or into, the stator  14  when the coil  16  is energized. Pulling the armature portion  20  decreases the relative distance between the stator  14  and armature  20 , which may increase the magnitude of the magnetic stator force  18  and counteract the increasing force occurring from compression of the return spring  24  and pushing the armature portion  20  rightward. Furthermore, the change of magnetic force can vary depending on the design and range of motion. 
     Due to tight tolerances between the stator  14  and armature portion  20 , the solenoid valve  10  includes a piloting feature  30  which is operatively connected to the housing  12 . The piloting feature is configured to align and guide the armature portion  20  as it moves or oscillates within the stator  14 . The piloting features  30  may also help align and guide the armature portion  20  as it is assembled or joined to the housing  12  and stator  14 . 
     The piloting feature  30  may therefore increase the ease of assembling the solenoid valve  10 . As shown in  FIG. 1 , the piloting feature  30  may include a bushing  32  disposed annularly about an interface between the housing  12  and armature portion  20 . The bushing  32  further assists in aligning and guiding assembly and movement of the armature portion  20 . Misalignment of the armature portion  20  within the stator  14  may cause cocking or binding of the armature portion  20  and prevent proper operation of the solenoid valve  10 . 
     The armature portion  20  further includes a first mating feature  34  on the end adjacent to the spool portion  22 . The spool portion  22  further includes a second mating feature  36 , which is configured to mate with, or be joinable to, the first mating feature  34 . When the first and second mating features  34 ,  36  are attached, the armature portion  20  and spool portion  22  move together. Note that without the first and second mating features  34 ,  36 , the return spring  24  would separate the spool portion  22  from the armature portion  20  as the stator  14  pulls the armature portion  20  leftward toward the housing  12  and the return spring  24  pushes the spool portion  22  rightward toward the valve body  26 . 
     The first mating feature  34  may be, for example, and without limitation: a threaded end, a keyed end, a tongue end, or another suitable mating feature recognizable to those having ordinary skill in the art. Similarly, the second mating feature  36  may be, for example, and without limitation: a threaded receptacle, a key slot, a groove, or another suitable mating feature recognizable to those having ordinary skill in the art and corresponding to the specific first mating feature  34 . 
     The first and second mating features  34 ,  36  may also be configured to allow for slight misalignment of the axis or the armature portion  20  relative to the axis of the spool portion  22 , which may allow some flex (or slop) between the first and second mating features  34 ,  36 . Otherwise, differences between the respective axes of the armature portion  20  and spool portion  22  may cause cocking or binding of the armature portion  20  within the stator  14  as well as the spool portion  22  within the valve body  26 . 
     Referring now to  FIG. 2 , and with continued reference to  FIG. 1 , there is shown a solenoid valve  110 , which is configured as a pull-style solenoid valve. The coil  16  generates stator force  18 , which pulls an armature portion  120  leftward (as viewed in  FIG. 2 ) toward the stator  14  and coil  16 . 
     The return spring  24  provides an opposing force by pushing a spool portion  122  rightward. In both of the pull-style solenoid valves  10  and  110 , the spool portions  22 ,  122  are disposed on the opposite side of the return springs  24 ,  124  from the stators  14 . The piloting feature  30  of solenoid valve  110  also includes bushing  32  disposed annularly about the interface between the housing  12  and the armature portion  120 . 
     The armature portion  120  is integrally formed with the spool portion  122 . The armature and spool portions  120 ,  122  are part of a one-piece, combined armature-valve component  121 . The combined armature-valve component  121  oscillates within the stator  14  and valve body  26  similar to the armature portion  20  and spool portion  22  of  FIG. 1 . However, combined armature-valve component  121  does not include first and second mating features  34 ,  36 . Because the combined armature-valve component  121  includes both the armature and spool portions  120 ,  122 , the spool portion  122  of solenoid valve  110  is also formed from a magnetic material. 
     Referring now to  FIG. 3 , and with continued reference to  FIGS. 1-2 , there is shown a solenoid valve  210 , which is configured as a push-style solenoid valve. Unlike the solenoid valves  10  and  110  shown in  FIGS. 1 and 2 , the coil  16  is configured to generate a stator force  18  in the opposing direction. Stator force  18  applies a rightward force (as viewed in  FIG. 3 ), and pushes an armature portion  220  away from the stator  14  and coil  16 . 
     The return spring  224  still provides an opposing force, but the return spring  224  of solenoid valve  210  is disposed between a valve body  226  and a spool portion  222 . A boss  225  may be provided on the spool portion  222  to align and center the return spring  224 . Therefore, the return spring  224  increases the amount of force opposing movement of the spool portion  222  as the spool portion  222  is pushed into the valve body  226 . Conversely, the stator force  18  may be decreasing in magnitude as the armature portion  220  moves away from the stator  14 . 
     The armature portion  220  is integrally formed with the spool portion  222 . The armature and spool portions  220 ,  222  are part of a one-piece, combined armature-valve component  221 . The combined armature-valve component  221  oscillates within the stator  14  and valve body  226  similar to the combined armature-valve component  121  of  FIG. 2 , and also does not include first and second mating features  34 ,  36 . Because the combined armature-valve component  221  includes both the armature and spool portions  220 ,  222 , the spool portion  222  of solenoid valve  210  is also formed from a magnetic material. 
     Those having ordinary skill in the art will recognize that terms such as “above,” “below,” “upward,” “downward,” et cetera, are used descriptively of the figures, and do not represent limitations on the scope of the invention, as defined by the appended claims. While the best modes and other embodiments for carrying out the claimed invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.