Patent Publication Number: US-2011068286-A1

Title: Solenoid on-off valve

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a solenoid on-off valve configured to open and close a passage through which a fluid flows. 
     2. Description of the Related Art 
       FIG. 6  is a cross-sectional view showing a solenoid on-off valve  1  described in Japanese Laid-Open Patent Application Publication No. 2005-83533. The solenoid on-off valve  1  is provided in a fluid apparatus, such as a high-pressure gas tank, and is configured to be able to open and close a passage. The solenoid on-off valve  1  includes a housing  2 , a main valve body  3 , a pilot valve body  4 , and an electromagnetic drive unit  5 . A valve passage  6  connecting a primary port and a secondary port is formed at the housing  2 . The valve passage  6  is divided into a primary space  8  and a secondary space  9  by a valve port  7   a  defined by a valve seat  7  of the housing  2 . The primary space  8  is connected to the primary port, and the secondary space  9  is connected to the secondary port. 
     Further, the main valve body  3  having a bottomed tubular shape is provided in the housing  2  so as to be displaceable. A pilot passage  10  penetrating in an axial direction is formed at a bottom portion  3   a  of the main valve body  3 . Further, a main seat member  11  is provided at the bottom portion of the main valve body  3 . The main seat member  11  is provided to surround an outer opening of the pilot passage  10  and is configured to be pressed (seated) on the valve seat  7 . The main seat member  11  is pressed on the valve seat  7 , so that the main valve body  3  closes the valve port  7   a  to close the valve passage  6 . 
     A tip end portion  4   a  of the pilot valve body  4  is inserted into the main valve body  3 . The main valve body  3  and the pilot valve body  4  are coupled to each other so as to be relatively displaceable. A valve seat  12  is formed at the bottom portion  3   a  of the main valve body  3  so as to surround an opening of the pilot passage  10 . The valve seat  12  projects toward the tip end portion  4   a  of the pilot valve body  4 . A sub seat member  13  is provided at the tip end portion  4   a  of the pilot valve body  4  so as to be pressed on the valve seat  12 . The sub seat member  13  is pressed on the valve seat  12 , so that the pilot valve body  4  closes the pilot passage  10 . An electromagnetic drive unit  5  is provided at the pilot valve body  4 . The electromagnetic drive unit  5  causes the pilot valve body  4  to be displaced by electric power. By causing the pilot valve body  4  to be displaced, the main valve body  3  coupled thereto moves. 
     By driving the electromagnetic drive unit  5 , the pilot valve body  4  is relatively displaced with respect to the main valve body  3 , the sub seat member  13  is separated from the valve seat  12 , and the pilot passage  10  opens. Thus, the primary space  8  is connected to the secondary space  9  through the pilot passage  10 , and the pressure of the secondary space  9  increases. By the pressure increase of the secondary space  9 , a pressure difference between the primary space  8  and the secondary space  9  decreases. When the pressure difference becomes a predetermined pressure, the main valve body  3  moves to separate the main seat member  11  from the valve seat  7 . With this, the primary space  8  and the secondary space  9  are connected to each other through the valve port  7   a , and a gas in a pressure apparatus is supplied through the valve port  7   a  to an external device. 
     In valves, such as the solenoid on-off valve  1 , of prior arts, in order to prevent the gas from leaking from the primary space  8  to the secondary space  9 , generally, high processing accuracy is required for the main seat member  11  and the sub seat member  13 . Moreover, in the valves of the prior arts, such as the solenoid on-off valve  1  including the main valve body  3  and the pilot valve body  4 , these parts need to be placed with high positional accuracy when assembling them. In addition, considerably high positional accuracy is required for the main seat member  11  provided at the main valve body  3  and the sub seat member  13  provided at the pilot valve body  4 . In order to secure this considerably high positional accuracy, further high processing accuracy is required for the main seat member  11  and the sub seat member  13 . Therefore, if the main seat member  11  and the sub seat member  13  are manufactured with extremely high processing accuracy as required, a large amount of labor is required for the manufacture of the solenoid on-off valve  1 , and the manufacturing cost and the quality control cost become high. 
     Moreover, in the solenoid on-off valve  1 , the main seat member  11  and the sub seat member  13  are respectively fixed to the main valve body  3  and the pilot valve body  4  by an adhesive or the like. Therefore, each of the main seat member  11  and the sub seat member  13  is low in a repeated stress durability and a thermal durability. Regarding the adhesive fixing, since the main seat member  11  and the sub seat member  13  move when fixing them, the positioning thereof is difficult, and it is difficult to secure the alignment of the main seat member  11  and the sub seat member  13  with respect to the main valve body  3 , the pilot valve body  4 , and the like with high accuracy. 
     SUMMARY OF THE INVENTION 
     Here, a first object of the present invention is to provide a solenoid on-off valve which is easily manufactured even if high accuracy (such as flatness, squareness, and surface roughness) is required for a seat member. 
     A second object of the present invention is to provide a solenoid on-off valve in which the repeated stress durability and thermal durability of a portion of the seat member which portion is fixed to a main valve body are improved. 
     A third object of the present invention is to provide a solenoid on-off valve capable of easily positioning the seat member with respect to the main valve body. 
     A solenoid on-off valve of the present invention includes: a housing including a primary space connected to a primary port, a secondary space connected to a secondary port, and a valve port defined by a valve seat and connecting the primary space and the secondary space; a main valve body provided in the housing to be displaceable; a seat member provided at the main valve body and pressed on the valve seat to close the valve port; a pilot valve body coupled to the main valve body and relatively displaceable with respect to the main valve body; and an electromagnetic drive unit configured to displace the pilot valve body by an electromagnetic force, wherein the seat member is configured such that: a pilot passage is formed to connect the primary space and the secondary space; and the pilot valve body is pressed on the seat member to close the pilot passage. 
     In accordance with the present invention, the seat member which is pressed on the valve seat to close the valve port is configured such that the pilot valve body can be pressed on the seat member. With this, although the main seat member and the sub seat member are respectively provided at the main valve body and the pilot valve body in the prior art, the main seat member and the sub seat member can be integrally formed. Thus, the parts requiring high positional accuracy can be omitted from the prior art, and portions where the positional accuracy needs to be defined can be reduced as compared to the prior art. Moreover, by forming the pilot passage on the seat member, it becomes unnecessary to define the positional accuracy between the seat member and the pilot passage during assembly. With this, again, the portions where the positional accuracy needs to be defined can be reduced as compared to the prior art. As above, the number of portions where the positional accuracy needs to be defined is small. Therefore, the manufacture is easier than the prior art, 
     In the above invention, it is preferable that: the main valve body include at one end portion thereof a through hole portion through which the seat member is inserted; and the seat member include at an axially intermediate portion of an outer peripheral wall thereof a flange portion projecting in a radially outward direction and be fixed to the main valve body by fitting the flange portion in a concave portion formed at an axially intermediate portion of the through hole portion. 
     In accordance with the above configuration, by fitting the flange portion of the seat member in the concave portion of the through hole portion of the main valve body, the seat member is fixed to the main valve body without adhering the seat member to the main valve body. With this, the repeated stress durability and the thermal durability, which deteriorate by adhering different materials such as resin and metal, do not deteriorate. Therefore, the durabilities can be improved than before, and the reliability further improves. 
     In the above invention, it is preferable that: the through hole portion of the main valve body and the outer peripheral wall of the seat member be formed such that in a state where the seat member is pressed on the valve seat, a fluid flowing therebetween is introduced to the primary space. 
     In accordance with the above configuration, even if a portion between the through hole portion of the main valve body and the outer peripheral wall of the seat member is not completely sealed, the fluid in the primary space does not leak to the secondary space while the seat member is pressed on the valve seat. Therefore, the processing accuracy of the through hole portion of the main valve body and the outer peripheral wall of the seat member can be reduced. Thus, the main valve body and the seat member can be easily manufactured, and the manufacturing cost can be reduced. 
     In the above invention, it is preferable that the seat member be formed by insert molding in the through hole portion of the main valve body. In accordance with the above configuration, the seat member is formed by insert molding in the main valve body, and the positioning of the seat member with respect to the main valve body is easy. Therefore, the manufacturing cost is reduced. 
     The above and further objects and features of the invention will more fully be apparent from the following detailed description with accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view showing a solenoid on-off valve  20  of Embodiment  1  of the present invention. 
         FIG. 2  is a cross-sectional view enlarging a periphery of a seat member  25  of  FIG. 1 . 
         FIG. 3(   a ) is a cross-sectional view showing a state where a pilot valve body  23  is separated from the seat member  25 .  FIG. 3(   b ) is a cross-sectional view showing a state where the seat member  25  is separated from a valve seat  34 . 
         FIG. 4  is a cross-sectional view enlarging a periphery of a seat member  25 A of a solenoid on-off valve  20 A of Embodiment  2  of the present invention. 
         FIG. 5  is a cross-sectional view enlarging a periphery of a seat member  25 B of a solenoid on-off valve  20 B of Embodiment  3  of the present invention. 
         FIG. 6  is a cross-sectional view showing the solenoid on-off valve  1  described in Japanese Laid-Open Patent Application Publication No. 2005-83533. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiment  1   
       FIG. 1  is a cross-sectional view showing a solenoid on-off valve  20  of Embodiment  1  of the present invention. The solenoid on-off valve  20  is provided at a high-pressure gas tank (hereinafter may be simply referred to as a “tank”), such as a fuel tank of a natural gas vehicle, configured to store a high-pressure combustible gas (hereinafter may be simply referred to as a “gas”). The solenoid on-off valve  20  is a valve device configured to control the output of the gas in the tank. 
     The solenoid on-off valve  20  includes a housing  21 , a main valve body  22 , a seat member  25 , a pilot valve body  23 , and an electromagnetic drive unit  24 . The solenoid on-off valve  20  has a reference axis line L 1 , and an axis of each of the housing  21 , the main valve body  22 , the seat member  25 , the pilot valve body  23 , and the electromagnetic drive unit  24  coincides with the reference axis line L 1  In the following, a direction along the reference axis line L 1  is referred to as an axial direction Z, an upward direction on the sheet of  FIG. 1  is referred to as a first axial direction Z 1 , and a downward direction on the sheet of  FIG. 1  is referred to as a second axial direction Z 2 . 
     A valve chest  31  is formed at the housing  21  along the reference axis line L 1  so as to open in the first axial direction Z 1 . Moreover, a primary passage  32  extending in a direction perpendicular to the reference axis line L 1  is formed at the housing  21 . The primary passage  32  has one end connected to the valve chest  31  and the other end connected to the inside of the tank. Further, a secondary passage  33  is formed at the housing  21  along the reference axis line L 1 . The secondary passage  33  has one axial end connected to the valve chest  31  and the other end connected to a device, such as an engine of a natural gas vehicle, located outside the tank. A valve seat  34  having an annular shape projecting in the first axial direction Z 1  is formed around an opening of the secondary passage  33  which opening faces the valve chest  31 . In the present embodiment, an opening of the primary passage  32  which opening faces the inside of the tank is a primary port  35 , and an opening of the secondary passage  33  which opening faces the device located outside the tank is a secondary port  36 . Then, a valve port  34   a  is defined inside a tip end of the valve seat  34 . 
     The main valve body  22  is provided in the valve chest  31  of the housing  21  so as to be displaceable in the axial direction Z. The main valve body  22  is made of a metal material, such as brass or stainless steel, and is formed to have a bottomed cylindrical shape. A plurality of grooves  22   a  each extending in the axial direction of the main valve body  22  from one end to the other end are formed on an outer peripheral portion of the main valve body  22  so as to be arranged in a circumferential direction at regular intervals. Then, a through hole portion  37  penetrating in the axial direction is formed at a bottom portion of the main valve body  22 . The seat member  25  fits in the through hole portion  37 . Moreover, the pilot valve body  23  is inserted in an opening of the main valve body  22  which opening opens in the first axial direction Z 1 . 
       FIG. 2  is a cross-sectional view enlarging a periphery of the seat member  25  of  FIG. 1 . The seat member  25  is made of synthetic resin or synthetic rubber. Specifically, the seat member  25  is made of PEEK (polyether ether ketone) resin, fluoroethylene resin, polyacetal resin, or nylon monomer. The seat member  25  has a substantially disc shape, and an outer shape of the seat member  25  substantially coincides with the shape of an inner peripheral surface of the through hole portion  37 . A flange portion  38  projecting in a radially outward direction is formed at an axially intermediate portion of the outer peripheral portion of the seat member  25  over the entire outer peripheral portion in a circumferential direction. Then, a concave portion which is concave toward the radially outward direction is formed at the through hole portion  37  of the main valve body  22 . The flange portion  38  fits in the concave portion  39 , so that the seat member  25  is fixed. 
     As above, the seat member  25  is fixed to the main valve body  22  without adhering the seat member  25  to the main valve body  22 . Therefore, the repeated stress durability and the thermal durability, which deteriorate by adhering different materials such as resin and metal, do not deteriorate. Therefore, the durabilities can be improved than before, and the reliability further improves. 
     Moreover, the seat member  25  has a first axial end portion, which is larger in diameter than the valve port  34   a  and is pressed (seated) on the valve seat  34 . The seat member  25  is pressed on the valve seat  34  to close the valve port  34   a . Further, a pilot passage  40  penetrating along the reference axis line L 1  is formed at the seat member  25 . 
     The following will be explained in reference to  FIGS. 1 and 2 . The pilot valve body  23  is made of ferromagnet, such as electromagnetic stainless steel. The pilot valve body  23  is constituted by integrally forming a small-diameter pilot valve portion  41  and a large-diameter movable core  42  and has a substantially columnar shape. A tip end portion of the pilot valve portion  41  is inserted into the main valve body  22 . The pilot valve portion  41  and the main valve body  22  are coupled to each other such that a coupling pin  43  is inserted into a coupling hole  41   a  of the pilot valve portion  41  and a coupling hole  22   b  of the main valve body  22 . Each of the coupling holes  41   a  and  22   b  extends in a direction perpendicular to the reference axis line L 1 . The diameter of the coupling hole  41  a of the pilot valve portion  41  is larger than an outer diameter of the coupling pin  43 . Therefore, the pilot valve body  23  is configured to be relatively displaceable with respect to the main valve body  22  in the axial direction Z. 
     Moreover, a pilot valve seat portion  44  is formed at a tip end  41   b  of the pilot valve portion  41 . The pilot valve seat portion  44  projects in the second axial direction Z 2  and has a tapered shape which tapers toward a tip end thereof. The pilot valve seat portion  44  is pressed on the seat member  25  such shat a tip end portion thereof fits in the pilot passage  40 . The pilot valve portion  41  is configured to close the pilot passage  40  such that the tip end portion of the pilot valve seat portion  44  is pressed on the seat member  25 . The movable core  42  is integrally provided at a base end  41   c  of the pilot valve portion  41 . Then, the electromagnetic drive unit  24  configured to displace the movable core  42  is provided at the movable core  42 . 
     The electromagnetic drive unit  24  includes a solenoid casing  47 , a fixed magnetic pole  48 , a coil member  49 , and a guide member  50 . The solenoid casing  47  is formed to have a substantially cylindrical shape and includes inward flange portions  47   a  and  47   b  respectively at both end portions of the axial direction Z, each of the inward flange portions  47   a  and  47   b  extending in a radially inward direction. The coil member  49  fits between these two inward flange portions  47   a  and  47   b . The coil member  49  includes a bobbin  51  and a coil  52 . The bobbin  51  is formed to have a substantially cylindrical shape and includes outward flange portions  51   a  and  51   b  respectively at both end portions of the axial direction Z, each of the outward flange portions  51   a  and  51   b  extending in the radially outward direction. Then, the coil  52  around which a coil wire winds is provided between these outward flange portions  51   a  and  51   b . Moreover, the fixed magnetic pole  48  made of ferromagnet fits in an opening of the solenoid casing  47  which opening opens in the first axial direction Z 1 . 
     Further, the guide member  50  is provided inside the solenoid casing  47 . The guide member  50  is provided at the housing  21  such that an opening thereof which opens in the second axial direction Z 2  is connected to the valve chest  31  of the housing  21 . Moreover, the movable core  42  is inserted in the guide member  50  from the opening which opens in the second axial direction Z 2 , and the movable core  42  reaches the inside of the coil member  49 . A second axial end portion of the movable core  42  faces a first axial end portion of the fixed magnetic pole  48 . A compression coil spring  53  is provided between these second axial end portion and first axial end portion. The movable core  42  and the fixed magnetic pole  48  are provided to be spaced apart from each other. The movable core  42  is pressed by the compression coil spring  53  in the second axial direction Z 2 . Therefore, the pilot valve seat portion  44  of the pilot valve portion  41  is pressed against the seat member  25 . 
     In the present embodiment, the secondary passage  33 , the valve chest  31 , and the primary passage  32  constitute a valve passage  55 . In the valve passage  55 , a space located on the primary port  35  side of the valve port  34   a  is a primary space  56 , and a space located on the secondary port  36  side of the valve port  34   a  is a secondary space  57 . Therefore, the primary space  56  and the secondary space  57  are connected to each other by the valve port  34   a.    
       FIG. 3(   a ) is a cross-sectional view showing a state where the pilot valve body  23  is separated from the seat member  25 .  FIG. 3(   b ) is a cross-sectional view showing a state where the seat member  25  is separated from the valve seat  34 . In the solenoid on-off valve  20 , both the pilot passage  40  and the valve passage  55  are closed with the current not flowing through the coil  52 . With this, the primary space  56  and the secondary space  57  are blocked. In this case, depending on the processing accuracy of the seat member  25  and the main valve body  22 , a portion between the seat member  25  and the through hole portion of the main valve body  22  may not be completely sealed, and a gap  58  may be formed. However, since the first axial end portion of the seat member  25  is formed to be larger in diameter than the valve port  34   a , the gap  58  is connected to a space located on the radially outward side of the valve seat  34 , that is, the primary space  56 . Therefore, the gas is prevented from leaking from the gap  58  to the secondary space  57 . On this account, the processing accuracy of the through hole portion  37  of the main valve body  22  and an outer peripheral wall of the seat member  25  can be reduced. Thus, the main valve body  22  and the seat member  25  can be easily manufactured, and the manufacturing cost can be reduced. 
     Next, in the solenoid on-off valve  20 , when the current flows through the coil  52 , a magnetic force is generated, and the movable core  42  and the fixed magnetic pole  48  are magnetized. By this magnetization, the movable core  42  is magnetically attracted to the fixed magnetic pole  48 , and a force in a direction toward the fixed magnetic pole  48  (that is, the first axial direction Z 1 ) is applied to the movable core  42 . With this, the pilot valve body  23  is relatively displaced with respect to the main valve body  22  in the first axial direction Z 1  until the coupling pin  43  contacts the pilot valve body  23 . Thus, as shown in  FIG. 3(   a ), the pilot valve seat portion  44  is separated from the pilot passage  40 , and the pilot passage  40  opens. By opening the pilot passage  40 , the primary space  56  and the secondary space  57  are connected to each other by the pilot passage  40 , and the pressure of the secondary space  57  increases. 
     By the increasing of the pressure of the secondary space  57 , the pressure difference between the primary space  56  and the secondary space  57  decreases. When the pressure difference becomes a predetermined pressure, the main valve body  22  is pulled in the first axial direction Z 1 . by the pilot valve body  23  which is displaced by the magnetic force of the coil  52 , and the main valve body  22  moves in the first axial direction Z 1 . By the movement of the main valve body  22 , the seat member  25  is separated from the valve seat  34 , and the valve passage  55  opens. Thus, the gas in the tank flows through the valve passage  55  to the device located outside the tank. Specifically, the gas in the tank flows through the primary passage  32 , enters into the valve chest  31 , flows through the grooves  22   a  of the main valve body  22 , is introduced into the secondary passage  33 , and flows to the device located outside the tank. 
     By stopping the current flowing through the coil  52 , the magnetic force applied to the pilot valve body  23  disappears, and the pilot valve body  23  is pressed on the seat member  25  by the pressing force of the compression coil spring  53 . With this, the pilot passage  40  is closed. After that, the pilot valve body  23  which is continuously pressed by the compression coil spring  53  presses the main valve body  22  to cause the main valve body  22  to move in the second axial direction Z 2 . Then, the seat member  25  provided at the main valve body  22  is pressed on the valve seat  34  to close the valve passage  55 . 
     In accordance with the solenoid on-off valve  20  of the present embodiment, the seat member  25  configured to be pressed on the valve seat  34  to close the valve passage  55  is configured such that the pilot valve body  23  can be pressed on the seat member  25 . With this, although the main seat member  11  and the sub seat member  13  are respectively formed for the main valve body  3  and the pilot valve body  4  in the prior art, the main seat member  11  and the sub seat member  13  can be integrally formed. Thus, the parts requiring high positional accuracy can be omitted from the valve of the prior art, and portions where the positional accuracy needs to be defined can be reduced as compared to the valve of the prior art. Moreover, by forming the pilot passage  40  on the seat member  25 , it becomes unnecessary to define the positional accuracy between the seat member  25  and the pilot passage  40  during assembly. With this, again, the portions where the positional accuracy needs to be defined can be reduced as compared to the prior art. As above, the number of portions where the positional accuracy needs to be defined is small. Therefore, even if high accuracy (such as flatness, squareness, and surface roughness) is required for the seat member  25 , high processing accuracy after assembly can be achieved more easily than the prior art, and the manufacture is easier than the prior art. 
     The seat member  25  of the present embodiment is formed by insert molding in the main valve body  22 . Therefore, the positioning of the seat member  25  with respect to the main valve body  22  is easy. On this account, the manufacturing cost is reduced. 
     Embodiment  2   
       FIG. 4  is a cross-sectional view enlarging a periphery of a seat member  25 A of a solenoid on-off valve  20 A of Embodiment  2  of the present invention. The configuration of solenoid on-off valve  20 A of Embodiment  2  is similar to that of the solenoid on-off valve  20  of Embodiment  1 . Therefore, in the following, only components of the solenoid on-off valve  20 A of Embodiment  2  which are different from the components of the solenoid on-off valve  20  of Embodiment  1  will be explained. The same reference numbers are used for the same components, and a repetition of the same explanation is avoided. The same is true for a solenoid on-off valve  20 B of Embodiment  3  described below. A pilot valve seat portion  44 A formed at a tip end of a pilot valve portion  41 A of a pilot valve body  23 A has a tapered shape which tapers toward a tip end thereof, and the tip end of the pilot valve seat portion  44 A is formed to be flat. The tip end portion of the pilot valve seat portion  44 A does not fit in the pilot passage  40  of the seat member  25 A but is pressed on the seat member  25 A to close the pilot passage  40 . 
     The solenoid on-off valve  20 A of the present embodiment has the same operational advantages as the solenoid on-off valve  20  of Embodiment  1 . 
     Embodiment  3   
       FIG. 5  is a cross-sectional view enlarging a periphery of a seat member  25 B of the solenoid on-off valve  2013  of Embodiment  3  of the present invention. The seat member  25 B includes a valve seat  61  at a second axial end portion thereof. The valve seat  61  is formed in an annular shape so as to surround a periphery of the pilot passage  40  and projects in the first axial direction Z 1 . Moreover, a tip end of a pilot valve portion  41 B of a pilot valve body  23 B is formed to be flat and is configured to be pressed on the valve seat  61 . When the pilot valve portion  41 B is pressed on the valve seat  61 , the pilot passage  40  is closed. 
     The solenoid on-off valve  20 B of the present embodiment has the same operational advantages as the solenoid on-off valve  20  of Embodiment  1 . 
     Embodiments  1  to  3  has explained a case where the present invention is applied to the high-pressure gas tank. However, the present invention may be applied to a hydraulic device, and the fluid used is not limited to the gas. Moreover, Embodiments  1  to  3  has explained a case where the housing  2  and the solenoid casing  47  are separately formed. However, these may be integrally founed. 
     As this invention may be embodied in several forms without departing from the spirit of essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within metes and bounds of the claims, or equivalence of such metes and bounds thereof are therefore intended to be embraced by the claims.