Patent Publication Number: US-11047352-B2

Title: Fuel injection valve

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application a continuation of Ser. No. 15/564,515, filed Oct. 5, 2017, which is the U.S. national phase of International Application no. PCT/JP2016/001894 filed Apr. 4, 2016 and claims priority to Japanese Patent Application No. 2015-78329 filed on Apr. 7, 2015, each of which is hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a fuel injection valve that injects fuel at an internal combustion engine (hereinafter referred to as an engine). 
     BACKGROUND ART 
     Previously, there is known a fuel injection valve that injects fuel from an inside to an outside of a housing by opening/closing an injection hole of the housing through reciprocation of a needle. For example, the patent literature 1 recites a fuel injection valve that includes: a movable core; a stationary core; a coil; a needle that is reciprocatable integrally with the movable core and opens or closes an injection hole when the needle moves away from or contacts a valve seat in response to movement of the movable core; a valve closing spring that urges the movable core in a valve closing direction; and a valve opening spring that urges the movable core in a valve opening direction. 
     In the fuel injection valve of the patent literature 1, one end of the valve opening spring contacts the movable core, and the other end of the valve opening spring contacts a support member that is provided to the housing or the needle. At the time of valve opening of the fuel injection valve of the patent literature 1, when the movable core is excessively moved in the valve closing direction, the valve opening spring is compressed more than a specified amount. When the movable core rebounds due to the urging force of the valve opening spring, which is compressed more than the specified amount, the needle is moved in the valve opening direction once again to execute unexpected fuel injection. 
     CITATION LIST 
     Patent Literature 
     
         
         PATENT LITERATURE 1: JP2012-97728A (corresponding to US2012/0080542A1) 
       
    
     SUMMARY OF INVENTION 
     It is an objective of the present disclosure to provide a fuel injection valve that can limit excessive movement of a movable core in a valve closing direction at a valve closing time. 
     Means for Achieving Objective 
     The present disclosure provides a fuel injection valve that includes a housing, a needle member, a stationary core, a movable core, a coil, a first urging member, a second urging member, and a limiting member. 
     The housing includes an injection hole, through which fuel is injected, and a valve seat, which is formed around the injection hole. 
     The needle member has a flange, which is formed at a radially outer side of the needle member. When an end part of the needle member, which is located on the valve seat side, moves away from or contacts the valve seat, the needle member opens or closes the injection hole. 
     The movable core is installed on the valve seat side of the flange such that the movable core is movable relative to the needle member and is contactable with the flange on the valve seat side of the flange. 
     The limiting member is installed on a radially outer side of the needle member such that the limiting member enables movement of the movable core between the limiting member and the flange on the valve seat side of the flange. 
     The fuel injection valve of the present disclosure is characterized by that the limiting member includes a support portion, which supports another end of the second urging member, and a contact portion, which is contactable with the movable core on the valve seat side of the movable core, and the limiting member is capable of limiting movement of the movable core relative to the needle member toward the valve seat side when the movable core contacts the contact portion. 
     The fuel injection valve of the present disclosure has the limiting member that includes: the support portion, which supports the another end of the second urging member; and the contact portion, which is contactable with the movable core on the valve seat side of the movable core. At the time of valve closing of the fuel injection valve of the present disclosure, the movable core is moved integrally with the needle member in the valve closing direction. Although the needle member stops movement in the valve closing direction upon contacting of the needle member against the valve seat, the movable core is moved further in the valve closing direction by an inertial force. At this time, the movable core, which moves in the valve closing direction, contacts the contact portion of the limiting member, so that excessive movement of the movable core in the valve closing direction is limited. In this way, it is possible to limit reopening of the injection hole that would be made by movement of the needle member in the valve opening direction due to rebound of the movable core, which has moved excessively in the valve closing direction. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a cross-sectional view of a fuel injection valve according to a first embodiment of the present disclosure. 
         FIG. 2  is an enlarged view of a portion II in  FIG. 1 . 
         FIG. 3  is a cross-sectional view of a fuel injection valve according to a second embodiment of the present disclosure. 
         FIG. 4  is a cross-sectional view of a fuel injection valve according to a third embodiment of the present disclosure. 
         FIG. 5  is a cross-sectional view taken along line V-V in  FIG. 4 . 
         FIG. 6  is a cross-sectional view of a fuel injection valve according to a fourth embodiment of the present disclosure. 
         FIG. 7  is a cross-sectional view of a fuel injection valve according to a fifth embodiment of the present disclosure. 
         FIG. 8  is a cross-sectional view of a fuel injection valve according to a sixth embodiment of the present disclosure. 
         FIG. 9  is a cross-sectional view of a fuel injection valve according to another embodiment of the present disclosure. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, various embodiments of the present disclosure will be described with reference to the drawings. 
     First Embodiment 
       FIGS. 1 and 2  show a fuel injection valve  1  according to a first embodiment of the present disclosure.  FIGS. 1 and 2  show a valve opening direction, which is a moving direction of a needle  40  away from a valve seat  255 , and a valve closing direction, which is a moving direction of the needle  40  toward the valve seat  255  for contacting with the valve seat  255 . 
     The fuel injection valve  1  is used in, for example, a fuel injection device of an undepicted direct injection type gasoline engine and injects gasoline as fuel at a high pressure in the engine. The fuel injection valve  1  includes a housing  20 , a needle  40 , a movable core  50 , a stationary core  27 , a flange receiving member (serving as a gap forming member)  30 , a limiting member  35 , a coil  29 , a first spring (serving as a first urging member)  281 , and a second spring (serving as a second urging member)  282 . 
     As shown in  FIG. 1 , the housing  20  includes a first tubular member  21 , a second tubular member  22 , a third tubular member  23  and an injection nozzle  25 . The first tubular member  21 , the second tubular member  22  and the third tubular member  23  are respectively formed as a cylindrical tubular member. The first tubular member  21 , the second tubular member  22  and the third tubular member  23  are coaxially arranged in this order and are joined together. 
     The first tubular member  21  and the third tubular member  23  are made of a magnetic material, such as ferritic stainless steel, and are magnetically stabilized through a magnetic stabilization process. In contrast, the second tubular member  22  is made of a non-magnetic material, such as austenitic stainless steel. 
     The injection nozzle  25  is welded to an end part of the first tubular member  21 , which is opposite from the second tubular member  22 . The injection nozzle  25  is a bottomed tubular member made of metal, such as martensitic stainless steel. The injection nozzle  25  is quenched to have a predetermined hardness. The injection nozzle  25  includes an injecting portion  251  and a tubular portion  252 . 
     The injecting portion  251  is shaped into a form that is symmetrical about a central axis CAO of the housing  20 , which serves as a line of symmetry and is coaxial with a central axis of the fuel injection valve  1 . An outer wall  253  of the injecting portion  251  is formed to project from an inside of the injection nozzle  25  toward an outside of the injection nozzle  25 . The injecting portion  251  has a plurality of injection holes  26 , which communicate between the inside of the housing  20  and the outside of the housing  20 . A valve seat  255  is formed at an inner wall  254  of the injecting portion  251  at a location around inside openings of the injection holes  26 . 
     The tubular portion  252  is formed at a radially outer side of the injecting portion  251  such that the tubular portion  252  extends in an opposite direction that is opposite from the projecting direction of the outer wall  253  of the injecting portion  251 . One end part of the tubular portion  252  is joined to the injecting portion  251 , and the other end part of the tubular portion  252  is joined to the first tubular member  21 . 
     The needle  40  is made of metal, such as martensitic stainless steel. The needle  40  is quenched to have a hardness that is generally equal to the hardness of the injection nozzle  25 . 
     The needle  40  is received in the inside of the housing  20  in a manner that enables reciprocation of the needle  40 . The needle  40  includes a small diameter portion  411 , a large diameter portion  412 , a seal portion  42 , a slidable portion  44  and a flange  43 . The small diameter portion  411 , the large diameter portion  412 , the seal portion  42  and the flange  43  are formed integrally in one-piece. The small diameter portion  411 , the large diameter portion  412 , the seal portion  42  and the flange  43  correspond to a needle member of the present disclosure. 
     The small diameter portion  411  is shaped into a rod form and is placed in the inside of the first tubular member  21  in a manner that enables reciprocation of the small diameter portion  411 . The seal portion  42  is formed on the valve seat  255  side of the small diameter portion  411 . The large diameter portion  412  is formed on an opposite side of the small diameter portion  411 , which is opposite from the valve seat  255 . The end part of the small diameter portion  411 , which is located on the side where the large diameter portion  412  is formed, includes a flow passage  401 . The flow passage  401  serves as a fuel flow passage, through which the fuel is flowable. The flow passage  401  is communicated with openings  413 , each of which serves as a fuel flow passage and is formed to extend through a wall of the small diameter portion  411  in a radial direction. 
     The large diameter portion  412  is a portion that is shaped into a generally tubular form. An outer diameter of the large diameter portion  412  is larger than an outer diameter of the small diameter portion  411 . The large diameter portion  412  includes a flow passage  402  that is communicated with an opposite side of the needle  40 , which is opposite from the valve seat  255 , while the flow passage  402  serves as a fuel flow passage, through which the fuel is flowable. The flow passage  402  is communicated with the flow passage  401  of the small diameter portion  411 . 
     The seal portion  42  is abuttable against the valve seat  255 . When the seal portion  42  moves away from or contacts the valve seat  255 , the needle  40  opens or closes the injection holes  26  to communicate or discommunicate between the inside and the outside of the housing  20 . 
     The slidable portion  44  is formed at the seal portion  42  side of the small diameter portion  411 . Parts of an outer wall  441  of the slidable portion  44  are chamfered. Remaining parts of the outer wall  441  of the slidable portion  44 , which are not chamfered, are slidable along the inner wall of the injection nozzle  25 . In this way, reciprocation of the needle  40  is guided at an end part of the needle  40  located on the valve seat  255  side. 
     The flange  43  is a portion that is shaped into a generally circular ring form. The flange  43  is formed at a radially outer side of an end part of the large diameter portion  412 , which is opposite from the valve seat  255 . An end surface  431  of the flange  43 , which is located on the valve seat  255  side, is contactable with the movable core  50 . An end surface  432  of the flange  43 , which is opposite from the valve seat  255 , is formed to be flush with an end surface  414  of the large diameter portion  412 , which is located on the valve seat  255  side. 
     The movable core  50  is a generally tubular member that is made of a magnetic material, such as ferritic stainless steel. The movable core  50  is placed on the valve seat  255  side of the flange  43  in such a manner that the movable core  50  is movable relative to the needle  40 . 
     The movable core  50  includes a receiving hole  500 , through which the large diameter portion  412  is received. The movable core  50  includes a plurality of communication passages  501 , which are located on the radially outer side of the receiving hole  500  and communicate between the valve seat  255  side of the movable core  50  and an opposite side of the movable core  50 , which is opposite from the valve seat  255 . The fuel flows through the communication passages  501 . 
     An end surface  502  of the movable core  50 , which is opposite from the valve seat  255 , is formed to be contactable with the end surface  431  of the flange  43  and the stationary core  27 . As shown in  FIG. 2 , in a state where the plate portion  31  of the flange receiving member  30  contacts the large diameter portion  412  and the flange  43 , and the tubular portion  32  of the flange receiving member  30  contacts the movable core  50 , a gap  430  is formed between the end surface  502  and the end surface  431 . 
     The stationary core  27  is welded to the third tubular member  23  of the housing  20  and is fixed to the inside of the housing  20 . The stationary core  27  includes a stationary core main body portion  271  and a stationary core slidable portion  272 . 
     The stationary core main body portion  271  is made of a magnetic material, such as ferritic stainless steel. The stationary core main body portion  271  is magnetically stabilized through a magnetic stabilization process and is placed in a magnetic field, which will be described later and is formed by the coil  29 . 
     The stationary core slidable portion  272  is a tubular member that is placed in an inside of an end part of the stationary core main body portion  271 , which is located on the valve seat  255  side. For example, chromium plating is applied to a surface of the stationary core slidable portion  272 , so that the stationary core slidable portion  272  has a hardness that is generally equal to the hardness of the flange receiving member  30 , the hardness of the flange  43  and the hardness of the movable core  50 . As shown in  FIG. 2 , the stationary core slidable portion  272  is formed such that an end surface  273  of the stationary core slidable portion  272 , which is located on the valve seat  255  side, is placed on the valve seat  255  side of an end surface  274  of the stationary core main body portion  271 , which is located on the valve seat  255  side. Thereby, when the movable core  50  moves in the valve opening direction, the end surface  502  of the movable core  50  contacts the end surface  273  of the stationary core slidable portion  272 , so that movement of the movable core  50  in the valve opening direction is limited. 
     The flange receiving member  30  is located on the radially inner side of the stationary core slidable portion  272  and is placed between the first spring  281  and the movable core  50 . The flange receiving member  30  includes the plate portion  31  and the tubular portion  32 . The plate portion  31  and the tubular portion  32  are formed integrally in one-piece. 
     The plate portion  31  is located on an opposite side of the flange  43 , which is opposite from the valve seat  255 . The plate portion  31  includes an end surface  311  that is contactable with the end surface  414  of the large diameter portion  412  and the end surface  432  of the flange  43 . The plate portion  31  includes a through-hole  312  that extends through the plate portion  31  in an axial direction of the central axis CAO. The through-hole  312  communicates between an outside and an inside of the flange receiving member  30 . 
     The tubular portion  32  is a portion that is shaped into a tubular form such that the tubular portion  32  extends from a radially outer end part of the plate portion  31  in the direction toward the valve seat  255 . The tubular portion  32  has an inner wall that is formed to be slidable with an outer wall of the flange  43  located at the radially outer side. The outer wall of the tubular portion  32  is formed to be slidable with an inner wall of the stationary core slidable portion  272 . 
     An end surface  321  of the tubular portion  32 , which is located on the valve seat  255  side, is formed to be contactable with the end surface  502  of the movable core  50 . The tubular portion  32  has a length that enables reciprocation of the flange  43  in the inside of the flange receiving member  30 . The tubular portion  32  includes a communication passage  322  that communicates between the inside and the outside of the tubular portion  32 . The communication passage  322  is communicatable with the gap  430 . 
     The coil  29  is shaped into a tubular form and mainly surrounds a radially outer side of the second tubular member  22  and the third tubular member  23 . The coil  29  generates the magnetic field therearound when an electric power is supplied to the coil  29 . When the magnetic field is formed, a magnetic circuit is formed at the stationary core  27 , the movable core  50 , the first tubular member  21 , the third tubular member  23  and the holder  17 . 
     One end of the first spring  281  contacts an end surface  313  of the plate portion  31 , which is opposite from the valve seat  255 . The other end of the first spring  281  contacts an end surface  111  of an adjusting pipe  11 , which is located on the valve seat  255  side, while the adjusting pipe  11  is securely press fitted into the inside of the stationary core  27 . The first spring  281  urges the needle  40  toward the valve seat  255  side, i.e., urges the needle  40  in the valve closing direction. 
     One end of the second spring  282  contacts an end surface  503  of the movable core  50 , which is located on the valve seat  255  side. The other end of the second spring  282  is supported by the limiting member  35 , and thus the limiting member  35  corresponds to a spring retainer for retaining the other end of the second spring  282 . The second spring  282  urges the movable core  50  toward the side, which is opposite from the valve seat  255 , i.e., urges the movable core  50  in the valve opening direction. 
     An urging force of the second spring  282  is set to be smaller than an urging force of the first spring  281 . In this way, when the electric power is not supplied to the coil  29 , the seal portion  42  of the needle  40  is placed in a contact state where the seal portion  42  contacts the valve seat  255 , i.e., in a valve closing state. 
     The limiting member  35  is a member that is shaped into a generally tubular form and is placed at a location, which is on the valve seat  255  side of the flange  43  and is on a radially outer side of the small diameter portion  411  and the large diameter portion  412 . The limiting member  35  is fixed to the needle  40  by, for example, press fitting. The limiting member  35  includes: a tubular portion  36 , which serves as a communication passage forming portion; an inside projection  37 , which serves as a movable core side end part and a fixing portion; and an outside projection  38 , which serves as a support portion. The tubular portion  36  and the inside projection  37  correspond to a contact portion of the present disclosure. 
     The tubular portion  36  is placed on the radially outer side of the small diameter portion  411  and the large diameter portion  412 . A communication passage  360  is formed between an inner wall  361  of the tubular portion  36  and an outer wall  415  of the small diameter portion  411 . The communication passage  360  communicates between the openings  413  of the small diameter portion  411  and the outside of the limiting member  35 . An end surface  362  of the tubular portion  36 , which is opposite from the valve seat  255 , is formed to be contactable with the end surface  503  of the movable core  50 . The inner edge section  363  of the tubular portion  36 , which is located on the valve seat  255  side, has a slope surface that is progressively spaced away from a central axis CAO of the tubular portion  36 , which is coaxial with the central axis of the limiting member  35 , from the opposite side, which is opposite from the valve seat  255 , toward the valve seat  255  side. 
     The inside projection  37  is placed on the radially inner side of the tubular portion  36 . The inside projection  37  is formed to project from an end part of the tubular portion  36 , which is opposite from the valve seat  255 , in a radially inner direction of the tubular portion  36 . An inner wall  371  of the inside projection  37  is fixed to an outer wall  416  of the large diameter portion  412 . An end surface  372  of the inside projection  37 , which is opposite from the valve seat  255 , is flush with the end surface  362  of the tubular portion  36  and is formed to be contactable with the end surface  503  of the movable core  50 . 
     The outside projection  38  is formed to project from an end part of the tubular portion  36 , which is located on the valve seat  255  side, toward a radially outer side of the tubular portion  36 . An end surface  381  of the outside projection  38 , which is opposite from the valve seat  255 , supports the second spring  282 . 
     A fuel inlet pipe  12 , which is shaped into a tubular form, is press fitted into and is welded to an end part of the third tubular member  23 , which is opposite from the second tubular member  22 . A filter  13  is installed in an inside of the fuel inlet pipe  12 . The filter  13  collects foreign objects contained in fuel, which flows from an inlet  14  of the fuel inlet pipe  12  to the filter  13 . 
     A radially outer side of the fuel inlet pipe  12  and a radially outer side of the third tubular member  23  are insert molded by resin. A connector  15  is formed at this molded portion. Terminals  16 , through which the electric power is supplied to the coil  29 , are insert molded in the connector  15 . A holder  17 , which is shaped into a tubular form and covers the coil  29 , is placed on a radially outer side of the coil  29 . 
     The fuel, which is inputted from the inlet  14  of the fuel inlet pipe  12 , flows in the inside of the stationary core  27 , the inside of the adjusting pipe  11 , the through-hole  312 , the flow passages  402 ,  401 , the openings  413 , the communication passage  360 , and the gap between the first tubular member  21  and the small diameter portion  411  and is guided into the inside of the injection nozzle  25 . Furthermore, a portion of the fuel, which flows in the inside of the adjusting pipe  11 , flows through the communication passages  501  and the gap between the first tubular member  21  and the limiting member  35  and is guided into the inside of the injection nozzle  25 . That is, the passage from the inlet  14  of the fuel inlet pipe  12  to the gap between the first tubular member  21  and the small diameter portion  411  serves a fuel passage  18 , which guides the fuel into the inside of the injection nozzle  25 . 
     Next, the operation of the fuel injection valve  1  will be described. 
     When the electric power is not supplied to the coil  29 , the seal portion  42  of the needle  40  contacts the valve seat  255 . At this time, the needle  40 , the movable core  50  and the flange receiving member  30  have the positional relationship shown in  FIG. 2 . Specifically, a magnetic attractive force is not generated between the stationary core  27  and the movable core  50 , so that a gap is formed between the stationary core  27  and the movable core  50 . Furthermore, the large diameter portion  412  and the flange  43  contact the plate portion  31 , and the tubular portion  32  contacts the movable core  50 . Thus, the gap  430  is formed. The gap  430  is filled with the fuel that flows in the fuel passage  18 . 
     When the electric power is supplied to the coil  29 , the magnetic attractive force is generated between the stationary core  27  and the movable core  50 . Thereby, in response to balance among the urging force of the first spring  281 , the urging force of the second spring  282  and the magnetic attractive force, the movable core  50  moves and accelerates in the valve opening direction through a distance, which corresponds to a length of the gap  430  in the axial direction of the central axis CAO, and then the end surface  502  of the movable core  50  contacts the end surface  431  of the flange  43 . At this time, the fuel in the gap  430  outflows to the outside of the flange receiving member  30  through the communication passage  322  of the tubular portion  32 . 
     Furthermore, the movable core  50  moves in the valve opening direction while maintaining the contact between the end surface  502  of the movable core  50  and the end surface  431  of the flange  43 . Thereby, the seal portion  42  moves away from the valve seat  255 , so that the injection holes  26  are opened. When the injection holes  26  are opened, the fuel, which is guided into the inside of the injection nozzle  25 , is injected to the outside through the injection holes  26 . When the movable core  50 , which moves in the valve opening direction, contacts the stationary core slidable portion  272 , the movement of the movable core  50  in the valve opening direction is stopped. 
     When the supply of the electric power to the coil  29  is stopped, the magnetic attractive force, which is generated between the stationary core  27  and the movable core  50 , is lost. Therefore, the movable core  50  and the flange receiving member  30  move in the valve closing direction in response to the urging force of the first spring  281  and the urging force of the second spring  282 . When the movable core  50  and the flange receiving member  30  move in the valve closing direction, the end surface  414  and the end surface  431  contact the end surface  311 . In this way, the needle  40  moves along with the movable core  50  and the flange receiving member  30  in the valve closing direction. 
     When the seal portion  42  contacts the valve seat  255  upon movement of the needle  40  in the valve closing direction, the injection holes  26  are closed. Thereby, the injection of the fuel is terminated. When the seal portion  42  contacts the valve seat  255 , the movement of the needle  40  in the valve closing direction is stopped. However, the movable core  50  is moved by the inertial force in the valve closing direction. At this time, a moving velocity of the movable core  50  in the valve closing direction is progressively reduced by the urging force of the second spring  282 . However, in a case where the moving velocity of the movable core  50  is not sufficiently reduced, the movable core  50  contacts the end surfaces  362 ,  372  of the limiting member  35  and thereby stops the movement in the valve closing direction. 
     The fuel injection valve  1  of the first embodiment includes the limiting member  35 , which supports the second spring  282  and is contactable with the movable core  50 . 
     At the time of valve closing of the fuel injection valve  1 , which has been in the valve opening state, the movable core  50  and the needle  40  are integrally moved in the valve closing direction. The movable core  50  moves further in the valve closing direction even when the needle  40  stops the movement thereof in the valve closing direction upon contacting of the needle  40  to the valve seat  255 . The limiting member  35  is formed to enable reciprocation of the movable core  50  between the limiting member  35  and the flange  43 . The limiting member  35  limits excessive movement of the movable core  50  in the valve closing direction after the contacting of the needle  40  to the valve seat  255 . In this way, it is possible to limit reopening of the injection holes  26  that would be otherwise caused by the movement of the needle  40  in the valve opening direction through rebound of the movable core  50  that is rebounded upon the excessive movement of the movable core  50  in the valve closing direction. 
     The limiting member  35  is placed on the radially outer side of the small diameter portion  411  and the large diameter portion  412  and supports one end of the second spring  282 . With this configuration, the urging force of the second spring  282  can be adjusted by adjusting a distance between the limiting member  35  and the movable core  50  at the time of manufacturing the fuel injection valve  1 . Thereby, the urging force of the second spring  282  can be adjusted with high accuracy. 
     Previously, the urging force of the urging member, which urges the movable core in the valve opening direction, is adjusted at the time of manufacturing the fuel injection valve in a state where the urging member, the needle and the movable core are installed to the housing that supports one end of the urging member. Therefore, the adjustment of the urging force of the urging member is relatively difficult, and the number of steps required for the adjustment is increased. 
     In the fuel injection valve  1 , the urging force of the second spring  282  can be adjusted based only on the relationship between the limiting member  35  and the movable core  50 . Thereby, the urging force can be relatively easily adjusted in comparison to the case where the one end of the urging means for urging the movable core in the valve opening direction is supported by the housing. 
     Furthermore, in the case of the fuel injection valve  1 , the urging force of the second spring  282  can be adjusted at the needle assembling step that assembles the movable core  50  and the needle  40  together. Therefore, there is no need for the injector assembling step that adjusts the urging force of the urging member after the assembling of the urging member, the needle and the movable core to the housing. Thereby, the number of the manufacturing steps of the fuel injection valve can be reduced. 
     The communication passage  360 , which forms the fuel passage  18 , is formed between the inner wall  361  of the tubular portion  36  and the outer wall  415  of the small diameter portion  411 . Thereby, the required amount of fuel, which is required for the fuel injection, can be reliably conducted from the inlet  14  of the fuel inlet pipe  12  to the inside of the injection nozzle  25 . 
     The inner edge section  363  of the tubular portion  36 , which is located on the valve seat  255  side, has a slope surface that is progressively spaced away from a central axis CAO of the tubular portion  36 , which is coaxial with the central axis of the limiting member  35 , from the opposite side, which is opposite from the valve seat  255 , toward the valve seat  255  side. Therefore, the fuel can be smoothly outputted from the communication passage  360  to the outside of the limiting member  35 . 
     The inside projection  37  of the limiting member  35 , which is formed at the opposite end part of the tubular portion  36  that is opposite from the valve seat  255 , is securely press fitted to the large diameter portion  412 , and thus the large diameter portion  412  corresponds to a press-fitting segment of the needle member. Thus, at the valve closing time of the fuel injection valve  1 , an impact force, which is exerted at the time of colliding the movable core  50  against the limiting member  35  upon movement of the movable core  50  in the valve closing direction, can be received with the inside projection  37 . Therefore, it is possible to limit occurrence of a damage of the limiting member  35  that would be otherwise caused by the impact force exerted at the time of colliding the movable core  50  against the limiting member  35 . 
     In the fuel injection valve  1 , at the valve opening time, the movable core  50  moves and accelerates in the valve opening direction through the distance that corresponds to the length of the gap  430  in the axial direction of the central axis CAO. The end surface  502  of the movable core  50  contacts the end surface  431  of the flange  43  in the state where the movable core  50  accelerates to some extent. Thereby, in the fuel injection valve  1 , a relatively large force in the valve opening direction can be exerted to the needle  40 . 
     Second Embodiment 
     Next, a fuel injection valve according to a second embodiment of the present disclosure will be described with reference to  FIG. 3 . The second embodiment differs from the first embodiment with respect to that a narrow space, which has a relatively small cross sectional area, is provided between the limiting member and the housing. Portions, which are substantially the same as those of the first embodiment, will be indicated by the same reference signs and will not be described redundantly.  FIG. 3  shows the valve opening direction, which is the moving direction of the needle  40  away from the valve seat  255 , and the valve closing direction, which is the moving direction of the needle  40  toward the valve seat  255  for contacting with the valve seat  255 . 
     In the fuel injection valve  2  of the second embodiment, the first tubular member  21  includes a flow passage that has a relatively small cross sectional area and is located on the valve seat  255  side of the outside projection  38  of the limiting member  35 . Specifically, as shown in  FIG. 3 , a gap (serving as the narrow space)  380  is formed between an end surface (serving as an end surface of the limiting member located on the valve seat side)  382  of the outside projection  38  located on the valve seat  255  side and the inner wall (serving as an inner wall of the housing that is opposed to the end surface of the limiting member located on the valve seat side)  211  of the first tubular member  21 , which is opposed to the end surface  382 . 
     In the fuel injection valve  2 , when the needle  40  is moved in the valve closing direction, the gap  380  is progressively reduced. Thereby, a damper effect is generated by the fuel in the gap  380 . The moving velocity of the needle  40  in the valve closing direction is reduced by the damper effect, so that collision of the needle  40  against the valve seat  255  at a relatively high velocity is limited. Thereby, in the second embodiment, it is possible to limit a damage of the seal portion  42  and the valve seat  255 , which would be otherwise caused by the collision of the seal portion  42  against the valve seat  255  at the valve closing time. 
     Third Embodiment 
     Next, a fuel injection valve according to a third embodiment of the present disclosure will be described with reference to  FIGS. 4 and 5 . The third embodiment differs from the first embodiment with respect to the shape of the limiting member. Portions, which are substantially the same as those of the first embodiment, will be indicated by the same reference signs and will not be described redundantly.  FIG. 4  shows the valve opening direction, which is the moving direction of the needle  40  away from the valve seat  255 , and the valve closing direction, which is the moving direction of the needle  40  toward the valve seat  255  for contacting with the valve seat  255 . 
     The fuel injection valve  3  of the third embodiment includes a limiting member  65 . The limiting member  65  is fixed to the needle  40  by press fitting and laser welding. The limiting member  65  includes a tubular portion (serving as a contact portion)  66  and an outside projection  38 . 
     The tubular portion  66  is placed on the radially outer side of the small diameter portion  411  and the large diameter portion  412 . At an inner wall  661  of the tubular portion  66 , an inner wall of an end part of the tubular portion  66 , which is opposite from the valve seat  255 , is fixed to the outer wall  416  of the large diameter portion  412 . Furthermore, at the inner wall  661  of the tubular portion  66 , an inner wall of an end part of the tubular portion  66 , which is located on the valve seat  255  side, is welded to the outer wall  415  of the small diameter portion  411  by laser welding. An end surface  662  of the tubular portion  66 , which is opposite from the valve seat  255 , is formed to be contactable with the end surface  503  of the movable core  50 . 
     The tubular portion  66  includes a plurality of communication holes  664 , which extend through a wall of the tubular portion  66  in the radial direction. As shown in  FIG. 5 , the communication holes  664  are formed at locations that correspond to the openings  413  of the small diameter portion  411 . Each of the communication holes  664  communicates between the corresponding opening  413  and the outside of the limiting member  65 . 
     In the fuel injection valve  3 , the end part of the limiting member  65 , which is opposite from the valve seat  255 , is fixed to the large diameter portion  412 , and the end part of the limiting member  65 , which is located on the valve seat  255  side, is laser welded to the small diameter portion  411 . The limiting member  65 , which has the two end parts fixed to the needle  40 , includes the communication holes  664 , each of which communicates between the corresponding opening  413  and the outside of the limiting member  65 . Each of the communication holes  664  forms a part of the fuel passage  18  and conducts the fuel between the opening  413  and the outside of the limiting member  65 . Thereby, the required amount of fuel, which is required for the fuel injection, can be reliably conducted from the inlet  14  of the fuel inlet pipe  12  to the inside of the injection nozzle  25 . 
     Furthermore, the end part of the limiting member  65 , which is located on the valve seat  255  side, is fixed to the small diameter portion  411  by the laser welding. In this way, at the valve closing time of the fuel injection valve  3 , the movement of the limiting member  65  in the valve closing direction, which is caused by the impact force exerted at the time of colliding the movable core  50  against the limiting member  35  upon movement of the movable core  50  in the valve closing direction, is limited. Therefore, it is possible to limit a change in the urging force of the second spring  282  through use of the fuel injection valve  3 . 
     Fourth Embodiment 
     Next, a fuel injection valve according to a fourth embodiment of the present disclosure will be described with reference to  FIG. 6 . The fourth embodiment differs from the first embodiment with respect to the shape of the needle and the shape of the limiting member. Portions, which are substantially the same as those of the first embodiment, will be indicated by the same reference signs and will not be described redundantly.  FIG. 6  shows the valve opening direction, which is the moving direction of the needle  70  away from the valve seat  255 , and the valve closing direction, which is the moving direction of the needle  70  toward the valve seat  255  for contacting with the valve seat  255 . 
     The fuel injection valve  4  of the fourth embodiment includes the needle  70  and the limiting member  75 . 
     The needle  70  includes the small diameter portion  711 , the large diameter portion  412 , the seal portion  42 , the slidable portion  44  and the flange  43 . The small diameter portion  711 , the large diameter portion  412 , the seal portion  42  and the flange  43  are formed integrally in one-piece. The small diameter portion  711 , the large diameter portion  412  and the seal portion  42  correspond to a needle member of the present disclosure. 
     The small diameter portion  711  is shaped into a rod form and is placed in the inside of the first tubular member  21  in a manner that enables reciprocation of the small diameter portion  711 . The seal portion  42  is formed on the valve seat  255  side of the small diameter portion  411 . The large diameter portion  412  is formed on an opposite side of the small diameter portion  411 , which is opposite from the valve seat  255 . The end part of the small diameter portion  711 , which is located on the side where the large diameter portion  412  is formed, includes a flow passage  701 . The flow passage  701  serves as a fuel flow passage, through which the fuel is flowable. The flow passage  701  is formed such that a length of the flow passage  701 , which is measured in the axial direction of the central axis CAO, is larger than that of the flow passage  401  of the first embodiment. The flow passage  701  is communicated with the flow passage  402 . The flow passage  701  is communicated with openings  713 , each of which serves as a fuel flow passage and is formed to extend through a wall of the small diameter portion  711  in the radial direction. The openings  713  are formed on the valve seat  255  side of the limiting member  75 , as shown in  FIG. 6 . 
     The limiting member  75  is fixed to the needle  40  by, for example, press fitting. The limiting member  75  includes a tubular portion (serving as a contact portion)  76  and an outside projection  38 . 
     The tubular portion  76  is placed on the radially outer side of the small diameter portion  411  and the large diameter portion  412 . At an inner wall  761  of the tubular portion  76 , an inner wall of an end part of the tubular portion  76 , which is opposite from the valve seat  255 , is fixed to the outer wall  416  of the large diameter portion  412 . Furthermore, at the inner wall  761  of the tubular portion  76 , an inner wall of an end part of the tubular portion  76 , which is located on the valve seat  255  side, forms a gap (serving as a damper space)  760  between the inner wall of the end part of the tubular portion  76  and the outer wall  715  of the small diameter portion  711 . The gap  760  has an opening  764  at the valve seat  255  side. The fuel can flow into or out of the gap  760 . An end surface  762  of the tubular portion  76 , which is opposite from the valve seat  255 , is formed to be contactable with the end surface  503  of the movable core  50 . The inner edge section  763  of the tubular portion  76 , which is located on the valve seat  255  side, has a slope surface that is progressively spaced away from the central axis CAO from the opposite side, which is opposite from the valve seat  255 , toward the valve seat  255  side. 
     The openings  713  of the needle  70 , which form the corresponding part of the fuel passage  18 , are formed on the valve seat  255  side of the limiting member  75 . Thereby, the required amount of fuel, which is required for the fuel injection, can be reliably conducted to the inside of the injection nozzle  25  without being interfered with the limiting member  75 . 
     At the fuel injection valve  4 , when the needle  70  is moved in the valve closing direction, the fuel is forced to flow in the gap  760  through the opening between the inner edge section  763  of the limiting member  75  and the outer wall  715  of the small diameter portion  711 . Because of the forced flow of the fuel into the gap  760 , an appropriate amount of resistance is applied to the needle  70 , and thereby a moving velocity of the needle  70  in the valve closing direction is reduced. Thereby, it is possible to limit collision of the needle  70  against the valve seat  255  at a relatively high velocity. As a result, in the fourth embodiment, it is possible to limit a damage of the seal portion  42  and the valve seat  255 , which would be otherwise caused by the collision of the seal portion  42  against the valve seat  255  at the valve closing time. 
     Furthermore, the inner edge section  763  of the tubular portion  76 , which is located on the valve seat  255  side and forms the gap  760 , has a slope surface that is progressively spaced away from the central axis CAO from the opposite side, which is opposite from the valve seat  255 , toward the valve seat  255  side. Thereby, the flow of the fuel into or out of the gap  760  can be smoothly carried out. 
     Fifth Embodiment 
     Next, a fuel injection valve according to a fifth embodiment of the present disclosure will be described with reference to  FIG. 7 . The fifth embodiment differs from the fourth embodiment with respect to provision of a movement limiting portion. Portions, which are substantially the same as those of the fourth embodiment, will be indicated by the same reference signs and will not be described redundantly.  FIG. 7  shows the valve opening direction, which is the moving direction of the needle  70  away from the valve seat  255 , and the valve closing direction, which is the moving direction of the needle  70  toward the valve seat  255  for contacting with the valve seat  255 . 
     The fuel injection valve  5  of the fifth embodiment includes the movement limiting portion  80 . The movement limiting portion  80  is a member that is shaped into a circular ring form and is fixed to the outer wall  715  of the small diameter portion  711  at a location that is on the valve seat  255  side of the limiting member  75 . The movement limiting portion  80  contacts the end surface  382  of the outside projection  38  of the limiting member  75 . 
     At the fuel injection valve  5 , the movement limiting portion  80  can limit movement of the limiting member  75  in the valve closing direction caused by the impact force exerted at the time of colliding the movable core  50  against the limiting member  75  upon movement of the movable core  50  in the valve closing direction. Thereby, the relative position of the limiting member  75 , which is relative to the movable core  50  through the needle  70  and defines the urging force of the second spring  282 , can be kept unchanged. 
     Sixth Embodiment 
     Next, a fuel injection valve according to a sixth embodiment of the present disclosure will be described with reference to  FIG. 8 . The sixth embodiment differs from the first embodiment with respect to presence of a gap between the flange and the movable core and a gap between the flange and the plate portion at the valve closing time. Portions, which are substantially the same as those of the first embodiment, will be indicated by the same reference signs and will not be described redundantly.  FIG. 8  shows the valve opening direction, which is the moving direction of the needle  40  away from the valve seat  255 , and the valve closing direction, which is the moving direction of the needle  40  toward the valve seat  255  for contacting with the valve seat  255 . 
       FIG. 8  is a cross-sectional view of the fuel injection valve  6  of the sixth embodiment. In a state shown in  FIG. 8 , the seal portion  42  contacts the valve seat  255 . At this time, the tubular portion  32  contacts the movable core  50 , and the movable core  50  contacts the limiting member  35 . Furthermore, the end surface  431  of the flange  43 , which is located on the valve seat  255  side, forms the gap  430  between the end surface  431  and the end surface  502 , and the end surface  432  of the flange  43 , which is opposite from the valve seat  255 , forms the gap  310  between the end surface  432  and the end surface  311  of the plate portion  31  of the flange receiving member  30 . 
     In the sixth embodiment, when the magnetic attractive force is generated between the stationary core  27  and the movable core  50  in the state shown in  FIG. 8 , the movable core  50  moves and accelerates in the valve opening direction through the distance, which corresponds to the length of the gap  430  in the axial direction of the central axis CAO, and then the end surface  502  of the movable core  50  contacts the end surface  431  of the flange  43 . Thereby, in the fuel injection valve  6 , a relatively large force in the valve opening direction can be exerted to the needle  40 . 
     Other Embodiments 
     (1) In the fuel injection valve of the respective embodiments described above, in the state where the plate portion of the flange receiving member contacts the needle, and the tubular portion of the flange receiving member contacts the movable core, the gap is formed between the end surface of the movable core, which is opposite from the valve seat, and the end surface of the flange, which is located on the valve seat side. Alternatively, it is possible to provide a fuel injection valve that does not have this gap.  FIG. 9  indicates a fuel injection valve  7  that does not have the flange receiving member. In this fuel injection valve  7 , when the seal portion  42  contacts the valve seat  255 , the end surface  431  of the flange  43  contacts the end surface  502  of the movable core  50 . Even in this fuel injection valve  7 , the provision of the limiting member of the present disclosure can limit the rebound of the movable core  50  by the limiting member  35  that supports the second spring  282 . 
     (2) In the fuel injection valve of the respective embodiments described above, the needle includes the fuel flow passage. Alternatively, the fuel flow passage may be eliminated from the needle. 
     (3) In the above embodiments, the limiting member includes the tubular portion and the outside projection. However, the configuration of the limiting member should not be limited to this configuration. It is only required that on the valve seat side of the flange, the movable core is installed such that the movable core is movable between the limiting member and the flange, and the limiting member includes the support portion and the contact portion while the contact portion is contactable with the movable core. 
     (4) In the first and second embodiments, the end surface of the inside projection, which is opposite from the valve seat, is flush with the end surface of the tubular portion, which is opposite from the valve seat. Alternatively, the end surface of the inside projection, which is opposite from the valve seat, may not be flush with the end surface of the tubular portion, which is opposite from the valve seat. It is only required that at least one of the end surface of the inside projection, which is opposite from the valve seat, or the end surface of the tubular portion, which is opposite from the valve seat, is contactable with the movable core at the time of moving the movable core in the valve closing direction. 
     (5) In the first and second embodiments, the end part of the limiting member, which is located on the movable core side, is securely press fitted to the large diameter portion. However, the location of press fitting the limiting member should not be limited to this location. 
     (6) In the fifth embodiment, the movement limiting portion is the single member that is shaped into the circular ring form. However, the shape and the number of the movement limiting portion(s) should not be limited to the above described shape and the number. The movement limiting portion may be made of a plurality of arcuate members and may be arranged one after another at equal intervals in a circumferential direction at, for example, the outer wall of the small diameter portion. In such a case, the damper space, which is formed between the outer wall of the small diameter portion of the needle and the inner wall of the limiting member, is communicated with the outside of the limiting member through gaps, each of which is defined between circumferentially adjacent two of the members of the movement limiting portion. Therefore, the fuel can be smoothly flown. 
     (7) The fuel injection valve of each of the fourth and fifth embodiments may include the narrow space that is formed between the end surface of the limiting member, which is located on the valve seat side, and the inner wall of the housing, which is opposed to the end surface of the limiting member. 
     (8) The fuel injection valve of the first to third embodiments may include the movement limiting portion. In such a case, the movement limiting portion is made of a plurality of arcuate members, so that the communication passage, which is formed between the outer wall of the small diameter portion of the needle and the inner wall of the limiting member, is communicated with the outside of the limiting member through gaps, each of which is defined between adjacent two of the members of the movement limiting portion. Therefore, the fuel can be smoothly flown. 
     The present disclosure should not be limited to the above embodiments and may be embodied in various forms without departing from the scope of the present disclosure.