Abstract:
A control valve for hydraulic media is provided. The control valve includes a valve body having four ports. A first seat, a second seat, and a dual seat are positioned in the valve body between the ports. Two poppets, each including a disc and a cup, with a spring located therebetween, are arranged on a cylindrical pin with an enlarged engagement portion that is slidably supported within the valve body. A solenoid assembly movable in an axial direction within the valve body contacts the cylindrical pin and adjusts the position of the discs and cups of the poppets with respect to the seats of the valve body to minimize unwanted leakage between the ports. This configuration comprises four variable orifices that cooperate to provide controlled flow during different energizing phases of the solenoid assembly.

Description:
INCORPORATION BY REFERENCE 
       [0001]    The following documents are incorporated herein by reference as if fully set forth: U.S. Provisional Application No. 61/813,991, filed Apr. 19, 2013. 
     
    
     FIELD OF INVENTION 
       [0002]    This application is generally related to a control valve and more particularly related to a poppet solenoid control valve. 
       BACKGROUND 
       [0003]    Control valves are widely used in various mechanical applications, including automotive and industrial applications, especially for variable cam timing applications in internal combustion engines. Existing control valves typically require high manufacturing tolerances for the control valve body. High tolerance valve bodies are relatively complicated and consequently are also expensive to manufacture. Known control valves are disclosed in U.S. Pat. No. 4,637,439, U.S. Pat. No. 5,513,832, and U.S. Pat. No. 6,322,468. 
         [0004]    Control valves also typically experience leakage between ports due to ineffective sealing. Leakage of hydraulic fluid between ports on a control valve compromises the control function, ultimately reducing the efficiency or operation of the associated engine element. 
       SUMMARY 
       [0005]    It would be desirable to provide a cost effective control valve that allows the use of more relaxed manufacturing tolerances and provides improved sealing against leakage between ports of the valve body. 
         [0006]    A control valve for hydraulic media is provided. The control valve includes a valve body defining an axial end port, a first peripheral control port, a second peripheral control port, and a medial peripheral port. A first seat is positioned in the valve body between the axial end port and the first peripheral control port. A dual seat surrounds the medial peripheral port and is positioned in the valve body between the first peripheral control port and the second peripheral control port. A second seat is positioned in the valve body between the second peripheral control port and a first axial end of the valve body opposite the axial end port. A first poppet, including a first disc, a first cup, and a first spring located therebetween, is positioned between the first seat and the dual seat. A second poppet, including a second disc, a second cup, and a second spring located therebetween, is positioned between the dual seat and the second seat. A cylindrical pin with an enlarged engagement portion is slidably supported within the valve body. A solenoid assembly including a sleeve and an armature movable in an axial direction with the armature contacts a first end of the cylindrical pin. A retainer biased by a return spring acts on a second end of the cylindrical pin. The first poppet is located on the cylindrical pin for sliding movement between the enlarged engagement portion and the retainer. The second poppet is located on the cylindrical pin for sliding movement between the enlarged engagement portion and the sleeve. The first and second poppets are pressed closed and the first peripheral control port is in fluid connection with the axial end port and the medial peripheral port is in fluid connection with the second peripheral control port when the solenoid assembly is in a deactivated state. The armature presses the cylindrical pin against the retainer when the solenoid assembly is actuated in a first state such that the first peripheral control port is isolated from fluid connection by the first disc contacting the first seat and the first cup contacting the dual seat, and the second peripheral control port is isolated from fluid connection by the second disc contacting the dual seat and the second cup contacting the second seat. The sleeve engages the second cup when the solenoid assembly is actuated in a second state, such that the second peripheral control port is in fluid connection with the axial end port, preferably via a passage through the cylindrical pin, and the medial peripheral port is in fluid communication with the first peripheral port. 
         [0007]    A method for assembling a control valve for hydraulic media is also provided. The method comprises providing a valve body including a housing, an axial end port, a first peripheral control port, a second peripheral control port, and a medial peripheral port. A first seat is inserted into the valve body from a first axial end of the valve body past the first peripheral control port, and the first seat is fixed within the valve body. A return spring, a retainer, a first poppet, and a dual seat are inserted from the first axial end of the valve body, such that a first end of the return spring engages a second axial end of the valve body and the retainer engages a second end of the return spring. The first poppet includes a first disc, a first cup, and a first spring located therebetween. A dual seat is fixed in position in the valve body such that the dual seat surrounds the medial peripheral port. The first spring biases the first disc against the first seat and biases the first cup against one side of the dual seat. A cylindrical pin with an enlarged engagement portion, a second poppet, and a second seat are inserted from the first axial end of the valve body. The second poppet includes a second disc, a second cup, and a second spring located therebetween that biases the second disc against a second side of the dual seat and biases the second cup against the second seat. The cylindrical pin extends through the first and second poppets. A solenoid assembly is inserted from the first axial end of the valve body, and the housing is closed at the second axial end of the valve body to seal the valve body. 
         [0008]    A method for calibrating a control valve for hydraulic media is also provided. The method comprises providing a valve body defining an axial end port, a first peripheral control port, a second peripheral control port, and a medial peripheral port. A first seat is positioned in the valve body between the axial end port and the first peripheral control port. A dual seat surrounds the medial peripheral port and is positioned in the valve body between the first peripheral control port and second peripheral control port. A second seat is positioned in the valve body between the second peripheral control port and an axial end of the valve body opposite the axial end port. A first poppet, including a first disc, a first cup, and a first spring located therebetween, is positioned between the first seat and the dual seat. A second poppet, including a second disc, a second cup, and a second spring located therebetween, is positioned between the dual seat and the second seat. A cylindrical pin with an enlarged engagement portion is slidably supported within the valve body and extends through the first and second poppets. Leakage of hydraulic media is detected between the axial end port, the first peripheral control port, the second peripheral control port, and the medial peripheral port based on a position of the first and second poppets. The position of the first seat, the dual seat, or the second seat is adjusted in the valve body based on the leakage that is detected in order to provide flow paths that are connected to or sealed from one another depending on a position of the cylindrical pin. 
         [0009]    Preferred arrangements with one or more features of the invention are described below and in the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The foregoing Summary as well as the following Detailed Description will be best understood when read in conjunction with the appended drawings. In the drawings: 
           [0011]      FIG. 1  is a schematic side view of a control valve according to the invention. 
           [0012]      FIGS. 2A-2C  are schematic side views of a control valve with a tank port on an axial end of a valve body according to the invention with a solenoid assembly in different states. 
           [0013]      FIGS. 3A-3C  are schematic side views of a control valve according to the invention with a supply pressure port on an axial end of a valve body with a solenoid assembly in different states. 
           [0014]      FIGS. 4A-4E  are schematic side views of the control valve illustrating an assembly method of the control valve. 
           [0015]      FIGS. 5A-5I  are schematic side views of the control valve illustrating a calibrating method of the control valve of  FIGS. 4A-4E . 
           [0016]      FIGS. 6A-6G  are schematic side views of a control valve illustrating another assembly method of a control valve. 
           [0017]      FIGS. 7A-7E  are schematic side views of a control valve illustrating a calibrating method of the control valve of  FIGS. 6A-6G . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0018]    Certain terminology is used in the following description for convenience only and is not limiting. The words “inner,” “outer,” “inwardly,” and “outwardly” refer to directions towards and away from the parts referenced in the drawings. A reference to a list of items that are cited as “at least one of a, b, or c” (where a, b, and c represent the items being listed) means any single one of the items a, b, c or combinations thereof. The terminology includes the words specifically noted above, derivates thereof, and words of similar import. 
         [0019]      FIG. 1  schematically shows a preferred embodiment of the control valve  1  according to the present invention. In the example embodiment shown, the control valve  1  includes a valve body  2  defining an axial end port  5 , a first peripheral control port  6 , a second peripheral control port  7 , and a medial peripheral port  8 . The valve body  2  may be formed from steel, aluminum, polymeric material, or any other suitable material. The axial end port  5  may be a tank port and the medial peripheral port  8  may be a supply pressure port. Alternatively, the medial peripheral port  8  may be the tank port and the axial end port  5  may be the supply pressure port. 
         [0020]    A first seat  10  is positioned in the valve body  2  between the axial end port  5  and the first peripheral control port  6 . A dual seat  14  surrounds the medial peripheral port  8  and is positioned in the valve body  2  between the first peripheral control port  6  and the second peripheral control port  7 . A second seat  12  is positioned in the valve body  2  between the second peripheral control port  7  and a first axial end  3  of the valve body  2  opposite the axial end port  5 . The seats may be formed from steel, aluminum, polymeric material, or any other suitable material. The dual seat  14  can be formed integral with the valve body  2  if polymeric material is used for the seats and the valve body  2 . 
         [0021]    A first poppet  18  is positioned between the first seat  10  and the dual seat  14 . The first poppet  18  includes a first disc  20 , a first cup  22 , and a first spring  24  located therebetween. The first spring  24  biases the first disc  20  against the first seat  10  and the first cup  22  against a first side of the dual seat  14 . The first peripheral control port  6  is sealed from supply pressure when the first disc  20  engages the first seat  10  and the first cup  22  engages the first side of the dual seat  14 . 
         [0022]    A second poppet  28  is positioned between the dual seat  14  and the second seat  12 . The second poppet  28  includes a second disc  30 , a second cup  32 , and a second spring  34  located therebetween. The second spring  34  biases the second disc  30  against a second side of the dual seat  14  and the second cup  32  against the second seat  12 . The second peripheral control port  7  is sealed from draining to the tank reservoir when the second disc  30  engages the second side of the dual seat  14  and the second cup  32  engages the second seat  12 . 
         [0023]    The sealing properties between the cups  22 ,  32  and the discs  20 ,  30  of the first and second poppets  18 ,  28  can be adjusted based on the material of these components. Material selection for these components can be optimized based on plastic or elastic deformation characteristics as desired for durability or leakage considerations. 
         [0024]    A cylindrical pin  38  with an enlarged engagement portion  40  is slidably supported within the valve body  2 . The cylindrical pin  38  may include a hollow center  42  which allows hydraulic media to flow between the second peripheral control port  7  and the axial end port  5 . A solenoid assembly  48  including a sleeve  52  and an armature  50  is movable in an axial direction with the armature  50  contacting a first end of the cylindrical pin  44 . 
         [0025]    A retainer  54  and a return spring  56  act on a second end  46  of the cylindrical pin  46 . The first poppet  18  is located on the cylindrical pin  38  for sliding movement between the enlarged engagement portion  40  and the retainer  54 . The second poppet  28  is located on the cylindrical pin  38  for sliding movement between the enlarged engagement portion  40  and the sleeve  52 . The first and second poppets  18 ,  28  are pressed closed by the return spring  56  acting on the retainer  54  and the enlarged engagement portion  40  acting on the second disc  30 , and the first peripheral control port  6  is in fluid connection with the axial end port  5  and the medial peripheral port  8  is in fluid connection with the second peripheral control port  7  when the solenoid assembly  48  is in a deactivated state. The solenoid assembly  48  may be a push or pull type such that the first and second poppets  18 ,  28  may be pressed closed in an activated or deactivated state. In the push type, the deactivated state corresponds to a “base state” in which a solenoid coil (not shown) is de-energized. The stiffness of the first spring  24 , the second spring  34 , and the return spring  56  may be adjusted depending on the amount of pressure forces exerted by hydraulic media in various applications. 
         [0026]    The armature  50  presses the cylindrical pin  38  against the retainer  54  when the solenoid assembly  48  is actuated in a first state such that the first peripheral control port  6  is isolated from fluid connection by the first disc  20  contacting the first seat  10  and the first cup  22  contacting the first side of the dual seat  14 , and the second peripheral control port  7  is isolated from fluid connection by the second disc  30  contacting the second side of the dual seat  14  and the second cup  32  contacting the second seat  12 . The first state corresponds to a “mid state” in which the solenoid coil is approximately 50% energized. 
         [0027]    The sleeve  52  engages the second cup  32  when the solenoid assembly  48  is actuated in a second state, such that the second peripheral control port  7  is in fluid connection with the axial end port  5 , and the medial peripheral port  8  is in fluid communication with the first peripheral control port  6 . The second state corresponds to an “end state” in which the solenoid coil is 100% energized.  FIGS. 2A-2C  show the three states of the solenoid assembly  48  discussed above for a valve body  2  with a tank port at the axial end port  5  of the valve body  2  and a supply pressure port at the medial peripheral port  8 .  FIGS. 3A-3C  show the same three states of the solenoid assembly  48  for a valve body  2  with a supply pressure port at the axial end port  5  of the valve body  2  and a tank port at the medial peripheral port  8 . 
         [0028]    As shown in  FIGS. 4A-4E , a method of assembling a control valve  1  for hydraulic media is provided. The method includes providing the valve body  2  including the housing, the axial end port  5 , the first peripheral control port  6 , the second peripheral control port  7 , and the medial peripheral port  8 . As shown in  FIG. 4A , the first seat  10  is inserted into the valve body  2  from the first axial end  3  of the valve body  2  past the first peripheral control port  6  and the first seat  10  is fixed within the valve body  2 . As shown in  FIG. 4B , the return spring  56 , the retainer  54 , the first poppet  18 , and the dual seat  14  are inserted from the first axial end  3  of the valve body  2 . The first end  58  of the return spring  56  engages the second axial end  4  of the valve body  2  and the retainer  54  engages the second end  60  of the return spring  56 . The first poppet  18  includes the first disc  20 , the first cup  22 , and the first spring  24  located therebetween. As shown in  FIG. 4C , the dual seat  14  is fixed in position in the valve body  2  such that the dual seat  14  surrounds the medial peripheral port  8 . The first spring  24  biases the first disc  20  against the first seat  10  and biases the first cup  22  against the dual seat  14 . As shown in  FIG. 4D , the cylindrical pin  38  with the enlarged engagement portion  40 , the second poppet  28 , and the second seat  12  are inserted into the valve body  2  from the first axial end  3 . The second poppet  28  includes the second disc  30 , the second cup  32 , and the second spring  34  located therebetween that biases the second disc  30  against the dual seat  14  and biases the second cup  32  against the second seat  12 . The cylindrical pin  38  extends through the first and second poppets  18 ,  28 . The enlarged engagement portion  40  may slidably engage the first cup  22  and the second disc  30 . As shown in  FIG. 4E , the solenoid assembly  48  is inserted into the valve body  2  from the first axial end  3 . The valve body housing is rolled at the first axial end  3  to seal the valve body  2 . 
         [0029]    Leakage may occur between ports of the valve body  2  when the solenoid assembly  48  is in the first state and the solenoid assembly  48  and the cylindrical pin  38  are in the mid state. Calibration of the seals between the ports may be performed using hydraulic fluid or air via a pneumatic device. As shown in  FIG. 5A , prior to sealing the valve body  2  by rolling the valve body housing at the first axial end  3 , an assembly seal aid  62  may be used to test the sealing function of the poppets and the leakage between the ports on the valve body  2 . The seal is positioned at the first axial end  3  of the valve body  2  and the cylindrical pin  38  may be adjusted to determine when the first and second poppets  18 ,  28  properly engage with their respective seats to seal the first and second peripheral control ports  6 ,  7 . 
         [0030]    As shown in  FIGS. 5B and 5C , if the first seat  10  is positioned too far away from the second axial end  4  of the valve body  2 , leakage occurs between the medial peripheral port  8  and the second peripheral control port  7  because the enlarged engagement portion  40  of the cylindrical pin  38  is preventing the second disc  30  from properly engaging with the dual seat  14  and the second poppet  28  cannot seal the second peripheral control port  7 . The position of the first seat  10  may be adjusted within the valve body  2  by pressing the cylindrical pin  38  until the enlarged engagement portion  40  engages the first poppet  18 , which then moves the first seat  10  in the axial direction towards the second axial end  4  of the valve body  2 . 
         [0031]    As shown in  FIGS. 5D and 5E , if the first seat  10  is positioned too close to the second axial end  4  of the valve body  2 , leakage occurs between the first peripheral control port  6  and the axial end port  5  during the first state because the enlarged engagement portion  40  is not engaging the first poppet  18 . The first poppet  18  is not properly sealing the first peripheral control port  6  because the first disc  20  is not engaging the first seat  10 . The position of the dual seat  14  may be adjusted by pressing the second poppet  28  against the dual seat  14  until the dual seat  14  moves in the axial direction towards the second axial end  4  of the valve body  2 . 
         [0032]    As shown in  FIGS. 5F and 5G , if the second seat  12  is positioned too close to the first axial end  3  of the valve body  2 , leakage occurs between the second peripheral control port  7  and the axial end port  5  because the second disc  30  is not contacting the second cup  32  and the second poppet  28  is not properly sealing the second peripheral control port  7  from the axial end port  5 . The position of the second seat  12  may be adjusted by pressing the second seat  12  deeper into the valve body  2 , away from the first axial end  3  of the valve body  2  until the second disc  30  engages the second cup  32  and the second peripheral control port  7  is sealed from the axial end port  5 . 
         [0033]    As shown in  FIGS. 5H and 51 , if the second seat  12  is positioned too far away from the first axial end  3  of the valve body  2 , leakage occurs between the first peripheral control port  6  and the medial peripheral port  8  and/or between the first peripheral control port  6  and the axial end port  5  because the first disc  20  is not contacting the first cup  22  and the first poppet  18  is not properly sealing the first peripheral control port  6 . The position of second seat  12  may be adjusted by pulling the cylindrical pin  38  towards the first axial end  3  of the valve body  2  until the enlarged engagement portion  40  of the cylindrical pin  38  engages the second poppet  28  and moves the second seat  12  in the axial direction closer to the first axial end  3  of the valve body  2 . 
         [0034]    In another embodiment, shown in  FIGS. 6A-6G , the method of assembling a control valve  1  for hydraulic media includes providing the valve body  2  including open first and second axial ends  3 ,  4 . The valve body  2  includes the housing, the first peripheral control port  6 , the second peripheral control port  7 , and the medial peripheral port  8 . As shown in  FIG. 6A , the dual seat  14  may be formed with the valve body  2  or the dual seat  14  may be inserted into the valve body  2  from either the first or second axial end  3 ,  4  and the dual seat  14  is fixed in position such that the dual seat  14  surrounds the medial peripheral port  8 . 
         [0035]    As shown in  FIG. 6B , the cylindrical pin  38  with the enlarged engagement portion  40 , and the first poppet  18 , including the first disc  20 , the first cup  22 , and the first spring  24  located therebetween, are inserted into the valve body  2  from the second axial end  4 . As shown in  FIG. 6C , the first seat  10  is inserted into the valve body  2  from the second axial end  4  of the valve body  2  and is fixed within the valve body  2  between the first peripheral control port  6  and the second axial end  4  of the valve body  2 . The first spring  24  biases the first disc  20  against the first seat  10  and the first spring  24  biases the first cup  22  against the dual seat  14 . 
         [0036]    As shown in  FIG. 6D , on the opposite side of the dual seat  14 , the second poppet  28 , including the second disc  30 , the second cup  32 , and the second spring  34  located therebetween, and the second seat  12  are inserted from the first axial end  3  of the valve body  2 . As shown in  FIG. 6E , the second seat  12  is fixed within the valve body  2  between the second peripheral control port  7  and the first axial end  3  of the valve body  2 . The second spring  34  biases the second disc  30  against the dual seat  14  and the second spring  34  biases the second cup  32  against the second seat  12 . The cylindrical pin  38  extends through the first poppet  18  and the second poppet  28  such that the enlarged engagement portion  40  may engage the first cup  22  and the second disc  30 . 
         [0037]    As shown in  FIG. 6F , the solenoid assembly  48 , including the sleeve  52  and the armature  50  movable in an axial direction, is inserted from the first axial end  3  of the valve body  2 . The valve body housing at the first axial end  3  is rolled to seal the valve body  2 . 
         [0038]    As shown in  FIG. 6G , the retainer  54  and the return spring  56 , including the first and second end  58 ,  60 , are inserted into the valve body  2  from the second axial end  4  of the valve body  2 . The first poppet  18  is located on the cylindrical pin  38  for sliding movement between the enlarged engagement portion  40  and the retainer  54 . The second poppet  28  is located on the cylindrical pin  38  for sliding movement between the enlarged engagement portion  40  and the sleeve  52 . An end cap defining the axial end port  5  is fixed to the second axial end  4  of the valve. The first end  58  of the return spring  56  engages the end cap, the second end  60  of the return spring  56  engages the retainer  54 , and the return spring  56  biases the retainer  54  against the first disc  20 . The end cap seals the second axial end  4  of the valve body  2 . 
         [0039]    As shown in  FIGS. 7A-7E , prior to sealing the second axial end  4  of the valve housing with the end cap, the seal of the first and second poppets  18 ,  28  may be tested to detect leakage. As shown in  FIGS. 7A and 7B , if the second seat  12  is positioned too far away from the first axial end  3  of the valve body  2 , the second poppet  28  will not disengage the second seat  12  at the proper time when the solenoid assembly  48  is actuated in the first state. This causes too much space between the sleeve  52  of the solenoid assembly  48  and the second cup  32  and negatively affects the sealing of the poppets. An engagement tool  64  may be used to push the cylindrical pin  38  in the axial direction such that the enlarged engagement portion  40  engages the second poppet  28  and the second poppet  28  pushes the second seat  12  towards the first axial end  3  of the valve body  2 . An assembly seal aid  62  surrounding the engagement tool  64  prevents hydraulic media from flowing between the first peripheral control port  6  and the axial end port  5  and allows detection of leakage between the second peripheral control port  7  and the axial end port  5  during calibration. 
         [0040]    As shown in  FIG. 7C , if the second seat  12  is too close to the first axial end  3  of the valve body  2 , it is pressed in the opposite direction until the second disc  30  engages the second cup  32  and leakage between the second peripheral control port  7  and the axial end port  5  is minimized. The relatively high contact area at the interface of the second cup  32  and the second disc  30  provides a low leakage seal compared to parallel leak paths between the cylindrical pin  38  and the solenoid assembly  48 , and between the solenoid assembly  48  and the valve body  2 . 
         [0041]    As shown in  FIG. 7D , if the first seat  10  is too close to the second axial end  4  of the valve body  2 , the first seat  10  is pressed in the axial direction with an assembly aid until the first disc  20  engages the first cup  22  and the first poppet  18  seals the first peripheral control port  6  from the axial end port  5 . As shown in  FIG. 7E , if the first seat  10  is too far away from the second axial end  4  of the valve body  2 , the first seat  10  can be pressed in the opposite direction via the cylindrical pin  38  by energizing the solenoid assembly  48 . Alternatively, an assembly aid can be used to apply force to the armature  50  to move the first seat  10  until leakage between the medial peripheral port  8  and the second peripheral control port  7  is minimized. 
         [0042]    Having thus described various embodiments of the present control valve in detail, it is to be appreciated and will be apparent to those skilled in the art that many changes, only a few of which are exemplified in the detailed description above, could be made in the apparatus without altering the inventive concepts and principles embodied therein. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore to be embraced therein. 
       LOG TO REFERENCE NUMBERS 
       [0000]    
       
         
           
               1  Control Valve 
               2  Valve Body 
               3  First Axial End of Valve Body 
               4  Second Axial End of Valve Body 
               5  Axial End Port 
               6  First Peripheral Control Port 
               7  Second Peripheral Control Port 
               8  Medial Peripheral Port 
               10  First Seat 
               12  Second Seat 
               14  Dual Seat 
               18  First Poppet 
               20  First Disc 
               22  First Cup 
               24  First Spring 
               28  Second Poppet 
               30  Second Disc 
               32  Second Cup 
               34  Second Spring 
               38  Cylindrical Pin 
               40  Enlarged Engagement Portion 
               42  Hollow Center 
               44  First End of Cylindrical Pin 
               46  Second End of Cylindrical Pin 
               48  Solenoid Assembly 
               50  Armature 
               52  Sleeve 
               54  Retainer 
               56  Return Spring 
               58  First End of Return Spring 
               60  Second End of Return Spring 
               62  Assembly Seal Aid 
               64  Engagement Tool