Patent Publication Number: US-8529220-B2

Title: High-pressure pump

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based on Japanese Patent Applications No. 2010-7899 filed on Jan. 18, 2010, and No. 2010-147696 filed on Jun. 29, 2010, the disclosures of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a high-pressure pump which pressurizes fuel by a plunger. 
     BACKGROUND OF THE INVENTION 
     A high-pressure pump has a plunger which reciprocates to pressurize fuel in a pressurizing chamber. JP-2003-113759A shows a high-pressure pump which has a valve body and a suction valve. The valve body and the suction valve are arranged in a fuel passage communicating with a pressurizing chamber. The suction valve is seated on or unseated from a valve seat provided to the valve body in order to adjust a fuel quantity introduced into the pressurizing chamber. 
     In this high-pressure pump, a fastening member is threaded into a housing and its axial fastening force is applied to the valve body through an engaging member so that the valve body is fixed in the housing. The axial fastening force of the fastening member is set a large value in order to avoid a loose of the fastening member. Thus, the engaging member between the fastening member and the valve body should have a mechanical strength against the axial fastening force. The engaging member has thickness enough to endure the axial fastening force. 
     Consequently, the size and weight of the high-pressure pump are increased and a manufacturing cost is also increased. 
     EP-1413756A1 shows a high-pressure pump which has an annular engagement groove on a fuel passage inner wall surface. An engaging member having C-shape is engaged with the annular engagement groove. The engaging member is also engaged with the valve body to prevent the valve body from moving opposite to the pressurizing chamber. The engaging member receives large pressure from the fuel in the pressurizing chamber at a surface contacting with the valve body. In order to reduce stress applied to the engaging member, the annular engagement groove should have great depth. When the C-shaped engaging member is brought into an engagement with the engagement groove, the engaging member should be deformed in such a manner that an outer diameter of the engaging member becomes smaller than an inner diameter of the annular engagement groove. If the engaging member is made from general material, it is likely that the engaging member is plastically deformed to loose a spring function. On the other hand, if the engaging member is made from material of which hardness is improved by heat-treating, it becomes difficult to deform the engaging member so as to engage the engaging member with the engagement groove. 
     SUMMARY OF THE INVENTION 
     The present invention is made in view of the above matters, and it is an object of the present invention to provide a high-pressure pump which is easily assembled and has high durability. 
     The high-pressure pump is provided with a plunger, a housing, an engaged member, an engaging member, and a resilient member. The housing has a pressurizing chamber where a fuel is pressurized by the plunger, a fuel passage which communicates with the pressurizing chamber, and an annular engagement groove which is formed on a passage wall defining the fuel passage. The engaged member is disposed inside of the passage wall. The engaging member is comprised of a plurality of arc-shaped plate members, which form circular shape. The engaging member is inserted into an engagement groove formed in the housing in such a manner as to be in contact with the engaged member. The resilient member is disposed inside of the engaging member in such a manner as to resiliently bias the arc-shaped plate members radially outwardly. Thereby, it is restricted that the engaging member is disengaged from the engagement groove. 
     When assembling the engaging member to the housing, a plurality of arc-shaped plate members are inserted into the engagement groove. Then, the resilient member is assembled inside of the engaging member. Since the engaging member is comprised of a plurality of arc-shaped plate members, it is unnecessary to elastically inwardly deform the engaging member when assembling the engaging member to the engagement groove. Thus, the plate members can be made of material having high hardness. Alternatively, the plate members can receive heat treating to improve the hardness thereof. The mechanical strength of the engaging member can be improved without deteriorating its assembling work. 
     Furthermore, according to the present embodiment, the engaged member can be positioned by the engaging member without utilizing an axial fastening force of a fastening member such as a bolt. Thus, it is unnecessary to configure the engaging member in such a manner as to receive the axial fastening force. The size of the high-pressure pump can be made smaller with low manufacturing cost. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other objects, features and advantages of the present invention will become more apparent from the following description made with reference to the accompanying drawings, in which like parts are designated by like reference numbers and in which: 
         FIG. 1  is a fragmentary sectional view showing a high-pressure pump according to a first embodiment of the present invention; 
         FIG. 2  is a sectional view showing a high-pressure pump according to the first embodiment; 
         FIG. 3A  is a front elevation view showing an engaging member which is comprised of two plate members; 
         FIG. 3B  is a cross sectional view taken along a line IIIB-IIIB of  FIG. 3A ; 
         FIG. 3C  is a front elevation view showing the engaging member in which two plates members are confronting to each other; 
         FIG. 4A  is a cross sectional view taken along a line IVA-IVA of  FIG. 1 ; 
         FIG. 4B  is a cross sectional view taken along a line IVB-IVB of  FIG. 4A ; 
         FIG. 5A  is a cross sectional view showing a situation where the engaging member is in contact with the valve body; 
         FIG. 5B  is a cross sectional view showing a situation where the engaging member is inserted into an engagement groove and a C-ring is engaged with an inner peripheral of the engaging member; 
         FIG. 6A  is a fragmentary sectional view showing an engaging member and its vicinity of the high-pressure pump according to a first embodiment; 
         FIG. 6B  is an enlarged view of a portion “B” in  FIG. 6A ; 
         FIG. 6C  is a front elevation view showing a C-ring; 
         FIG. 7  is a cross-sectional view showing a high-pressure pump according to a second embodiment of the invention; 
         FIG. 8  is a fragmentary cross-sectional view showing a high-pressure pump according to a third embodiment of the invention; 
         FIG. 9  is a fragmentary cross-sectional view showing a high-pressure pump according to a fourth embodiment of the invention; and 
         FIG. 10  is a fragmentary cross-sectional view showing a high-pressure pump according to a fifth embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Multiple embodiments of the present invention will be described with reference to accompanying drawings. In each embodiment, the substantially same parts and the components are indicated with the same reference numeral and the same description will not be reiterated. 
     First Embodiment 
       FIGS. 1 to 6  show a high-pressure pump according to a first embodiment. A high-pressure pump  10  is a fuel pump which supplies fuel to an injector of a diesel engine or a gasoline engine. 
     As shown in  FIG. 2 , the high pressure pump  10  is provided with a housing body  11 , a cover  12 , a plunger  13 , a valve body  30 , a valve member  400 , a spring  21 , a spring  22 , an electromagnetic driving portion  70 , a valve body engaging member  60 , and a C-ring  600 . The housing body  11  is made of martensite stainless steel and defines a cylinder  14  therein. The cylinder  14  receives a plunger  13  reciprocatably. 
     The housing body  11  defines an introduce passage  111 , a suction passage  112 , a pressurizing chamber  113 , and a discharge passage  114 . The housing body  11  has a cylinder portion  15 . The cylinder portion  15  defines a passage  151  fluidly connecting the introducing passage  111  and the suction passage  112 . This passage  151  corresponds to a part of a fuel passage of the present invention. The passage  151  is defined by a cylindrical passage wall surface  152  of the cylinder portion  15 . The cylinder portion  15  has an annular engagement groove  153  which is radially outwardly concaved on the passage wall surface  152 . An annular wall surface  154  is formed between the engagement groove  153  and the pressurizing chamber  113 . The valve body  30  is provided inside of the passage wall surface  152  between the engagement groove  153  and the annular wall surface  154 . 
     A fuel chamber  16  is formed between the housing body  11  and the cover  12 . The housing body  11  has a fuel inlet (not shown) communicating with the fuel chamber  16 . A low-pressure pump (not shown) pumps up the fuel from a fuel tank and supplies the fuel to the fuel chamber  16 . An introducing passage  111  communicates with the passage  151 . One end of the suction passage  112  communicates with the pressurizing chamber  113 . The other end of the suction passage  112  communicates with an interior of the annular wall surface  154 . The introducing passage  111  and the suction passage  112  communicate with each other through the valve body  30  as shown in  FIG. 1 . The pressurizing chamber  113  communicates with the discharge passage  114 . 
     The plunger  13  is accommodated in the cylinder  14  in such a manner as to reciprocate in its axial direction. A head  17  of the plunger  13  is engaged with a spring seat  18 . A spring  19  is provided between the spring seat  18  and an oil-seal holder  28 . The spring seat  18  is biased toward a cam (not shown) by the spring  19 . The plunger  13  is reciprocated by being contacted with the cam through a tappet. 
     One end of the spring  19  is engaged with the oil-seal holder  28  and the other end is engaged with the spring seat  18 . The spring  19  biases the tappet toward the cam through the spring seat  18 . A space between the plunger  13  and the oil-seal holder  28  is fluidly sealed by the oil seal  23 . The oil seal  23  prevents an engine-oil leakage from and into the pressurizing chamber  113 . 
     A discharge valve portion  90  having a fuel outlet  91  is provided to the housing body  11 . The discharge passage  114  communicates the pressurizing chamber  113  and the fuel outlet  91 . A discharge valve seat  95  is formed at inner wall of the housing body  11 . 
     The discharge valve portion  90  controls a discharge of fuel pressurized in the pressurizing chamber  113 . The discharge valve portion  90  is comprised of a discharge valve  92 , a regulation member  93 , and a spring  94 . The discharge valve  92  is made of martensite stainless steel of which hardness is improved by heat treating. The discharge valve  92  has a bottom portion  921  and a cylindrical portion  922 . The discharge valve  92  is slidably disposed in the discharge passage  114 . The regulation member  93  is arranged adjacent to the discharge valve  92 . The regulation member  93  is made of austenite stainless steel. The hardness of the regulation member  93  is lower than that of the discharge valve  92 . The regulation member  93  is press-fixed in the discharge passage  114 . One end of the spring  94  is engaged with the regulation member  93  and the other end is engaged with the cylindrical portion  922 . The discharge valve  92  is biased toward a discharge valve seat  95  by the spring  94 . When the discharge valve  92  seats on the discharge valve seat  95 , the discharge passage  114  is closed. When the discharge valve  92  moves away from the discharge valve seat  95 , the discharge passage  114  is opened. The regulation member  93  functions as a stopper of the discharge valve  92 . 
     When the fuel pressure in the pressurizing chamber  113  is increased, the fuel pressure which the discharge valve  92  receives is also increased. When fuel pressure in the pressurizing chamber  113  exceeds a specified value, the discharge valve  92  moves away from the discharge valve seat  95  against the biasing force of the spring  94 . The fuel in the pressurizing chamber  113  is discharged outside of the high-pressure pump  10  from the fuel outlet  91  through the discharge passage  114 , apertures  923  and the cylindrical portion  922 . 
     When the fuel pressure in the pressurizing chamber  113  is decreased, the fuel pressure which the discharge valve  92  receives is also decreased. When fuel pressure in the pressurizing chamber  113  becomes lower than the specified value, the discharge valve  92  sits on the discharge valve seat  95 . Thereby, it is prevented that the fuel in a delivery pipe (not shown) flows into the pressurizing chamber  113  through the discharge passage  114 . 
     The valve body  30  is made of martensite stainless steel. The valve body  30 , as shown in  FIG. 1 , is arranged inside of the passage wall surface  152  between the engagement groove  153  and the annular wall surface  154 . The valve body  30  is engaged with the passage wall surface  152  by means of a valve body engaging member  60  and a plate spring  80 . The C-ring  600  is made of austenite stainless steel and is engaged with an inner surface of the valve body engaging member  60 . The C-ring  600  has resilience in its radial outward direction. The C-ring  600  biases the valve body engaging member  60  radially outwardly so that it is prevented that the valve body engaging member  60  is disengaged from the engaging groove  153 . The valve body  30  corresponds to “an engaged member”, and the valve body engaging member  60  corresponds to “an engaging member” of the present invention. 
     The valve body  30  has a bottom portion  31  and a cylindrical portion  32 . The valve body  30  has a concaved portion  33 . A suction valve seat  34  is formed on an outer fringe of the concaved portion  33 . The suction valve seat  34  is tapered with respect to an axial line of the valve body  30 . 
     The valve body  30  has a first guide portion  35  at its bottom portion  31 . The valve body  30  has a first inserting hole  351 . Further, the valve body has a first passage  121 . A plurality of the first passages  121  are arranged circumferentially with respect to an axial line of the valve body  30 . 
     A seal member  36  and a backup ring  37  are provided between the cylindrical portion  32  and the passage wall surface  152 . The seal member  36  prevents a fuel leakage between the pressurizing chamber  113  and the introducing passage  111 . 
     A valve member  400  includes a suction valve  40  and a needle  49 . The valve member  400  is made of martensite stainless steel. In the present embodiment, the suction valve  40  and the needle  49  are formed from separate pieces. The suction valve  40  is comprised of a shaft portion  41  and a disc portion  42 . The shaft portion  41  is inserted into the first inserting hole  351  in such a manner that the suction valve  40  reciprocates in the valve body  30 . The disc portion  42  is formed so as to sit on the suction valve seat  34 . The suction valve  40  reciprocates so that the disc portion  42  sits on the suction valve seat  34  to close the passage  151  or moves away from the suction valve seat  34  to open the passage  151 . Further, when the disc portion  42  moves away from the suction valve seat  34 , a second passage  122  is defined between the suction valve  40  and the suction valve seat  34 . 
     An inner diameter of the first inserting hole is substantially equal to or slightly larger than an outer diameter of the shaft portion  41 . Thereby, the suction valve  40  reciprocates in the valve body  30  while the outer surface of the shaft portion  41  is slidably in contact with an inner wall surface of the first guide portion  35 . 
     A stopper  50  is provided adjacent to the suction valve  40 . The stopper  50  is comprised of a cylindrical portion  51 , a bottom portion  52 , and an enlarged portion  53 . The enlarged portion  53  is welded to an inner wall surface of the cylindrical portion  32  of the valve body  30 . 
     A spring  21  is provided between the stopper  50  and the suction valve  40 . One end of the spring  21  is engaged with the bottom portion  52  and the other end is engaged with the suction valve  40 . The spring  21  biased the suction valve  40  in its closing direction. 
     When the suction valve  40  is brought into a contact with the stopper  50 , a volume chamber  54  is defined by the cylindrical portion  51  and the bottom portion  52  of the suction valve  40 . The stopper  50  restricts a movement of the suction valve  40  in its opening direction. When the suction valve  40  is in contact with the cylindrical portion  51  of the stopper  50 , the stopper  50  covers a part of the suction valve  40 . Thereby, it is restricted that the fuel flowing to the suction valve  40  collides with the suction valve  40 . 
     The enlarged portion  53  of the stopper  50  is provided with a plurality of third passages  123 . Each of the third passages is arranged in a circumferential direction with respect to an axial line of the stopper  50 . An intermediate passage  124  is defined between the second passage  122  and the third passage  123 . The cylindrical portion  51  of the stopper  50  includes a communication passage  55  which connects the volume chamber  54  and the intermediate passage  124 . 
     The first passage  121 , the second passage  122 , the third passage  123 , and the intermediate passages  124  are included in the passage  151  formed in the housing body  11 . That is, the fuel flows from the fuel chamber  16  to the pressurizing chamber  113  through the first passage  121 , the second passage  122 , the intermediate passage  124 , and the third passage  123  in this series. Alternatively, the fuel flows from the pressurizing chamber  113  to the fuel chamber  16  through the third passage  123 , the intermediate passage  124 , the second passage  122 , and the first passage  121  in this series. 
     As shown in  FIG. 2 , the electromagnetic driving portion  70  is comprised of a coil  71 , a fixed core  72 , a movable core  73 , and a flange  75 . The coil  71  is winded around a spool  78 . When energized, the coil  71  generates a magnetic field. The fixed core  72  is made from magnetic material and is accommodated inside of the coil  71 . The movable core  73  is made from magnetic material and confronts to the fixed core  72 . The movable core  73  is slidably arranged in a cylindrical member  79  and the flange  75 . The cylindrical member  79  is made from nonmagnetic material and prevents a magnetic short circuit between the fixed core  72  and the flange  75 . 
     The flange  75  is made of magnetic material. As shown in  FIG. 1 , the flange  75  is fixed to the cylindrical portion  15  of the housing body  11 , so that the electromagnetic driving portion  70  is held in the housing body  11 . The flange  75  is provided with a second guide portion  76 . The second guide portion  76  defines a second inserting hole  761 . 
     The needle  49  is slidably inserted in the second inserting hole  761 . An inner diameter of the second inserting hole is substantially equal to or slightly larger than an outer diameter of the needle  49 . Thereby, the needle  49  reciprocates while its outer surface is slidably in contact with an inner wall surface of the second guide portion  76 . 
     The needle  49  is welded to the movable core  73 . The needle  49  can be in contact with the suction valve  40 . The needle  49  reciprocates along with the suction valve  40 . 
     A spring  22  is provided between the fixed core  72  and the movable core  73 . This spring  22  biases the movable core  73  toward the suction valve  40 . A biasing force of the spring  22  is greater than that of the spring  21 . That is, the spring  22  biases the movable core  73  and the needle  49  toward the suction valve  40  against a biasing force of the spring  21 . When the coil  71  is deenergized, the movable core  73  and the fixed core  72  are apart from each other. Therefore, while the coil  71  is not energized, the needle  49  is biased toward the suction valve  40  by the spring  22 , and the suction valve  40  is apart from the suction valve seat  34 . The coil  71 , the fixed core  72 , the movable core  73 , the flange  75 , the spool  78  and the cylindrical member  79  correspond to “a coil portion” of the present invention. 
     Referring to  FIGS. 3A to 4B , the valve body engaging member  60  and the engagement groove  153  will be described in detail. 
     As shown in  FIG. 3A , the valve body engaging member  60  is comprised of two plate members  61 ,  62 . These plate members  61 ,  62  are made of martensite stainless steel, and have substantially the same hardness of the valve body  30 . The hardness of the plate members  61 ,  62  is greater than that of the C-ring  600 . The first plate member  61  and the second plate member  62  are arc-shaped. As shown in  FIG. 3C , in a case that the first plate member  61  are confronted to the second plate member  62 , these plate members  61 ,  62  form an annular shape. In this situation, the valve body engaging member  60  has a first curved portion  63  and a second curved portion  64  of which curvature is different from each other. The first curved portion  63  and the second curved portion  64  are alternately formed in circumferential direction at intervals of 90°. 
     A curvature radius “Ra” of the first curved portion  63  is equal to a radius of a virtual circle “C 1 ” illustrated by an alternate long and short dash line. The virtual circle “C 1 ” has a center point indicated by a white circle. A curvature radius “Rb” of the second curved portion  64  is equal to a radius of a virtual circle “C 2 ” illustrated by a two-dot chain line. The virtual circle “C 2 ” has a center point indicated by a black circle. In the present embodiment, the curvature radius “Ra” is greater than the curvature radius “Rb” (Rb&lt;Ra). 
       FIG. 3B  is a cross sectional view taken along a line IIIB-IIIB in  FIG. 3A . The first and second plate members  61 ,  62  have a step surface  66  at its contacting surface  65  which is in contact with the valve body  30 . This step surface  66  defines a cylindrical step side wall  67 . 
     As shown in  FIGS. 4A and 4B , the engagement groove  153  is concaved radially outwardly on the passage wall surface  152  and is formed annularly along the passage wall surface  152 . In a case where an inner diameter of the engagement groove  153  is denoted by “Rc” and an outer diameter of the engagement groove  153  is denoted by “Rd”, a following relationship can be established.
 
Rb&lt;Rc&lt;Ra≦Rd  (1)
 
     Referring to  FIGS. 1 and 5 , an assembling way of the valve body  30 , the valve body engaging member  60 , the C-ring  600  and the plate spring  80  to the housing body  11  will be described. 
     (1) The plate spring  80  is arranged in such a manner as to be in contact with the annular wall surface  154  of the housing body  11  (refer to  FIG. 1 ). 
     (2) An assembly unit of the valve body  30 , the suction valve  40 , the stopper  50 , the spring  21 , the seal member  36  and the backup ring  37  is inserted into the passage  151  in such a manner that the valve body  30  is brought into contact with the plate spring  80 . 
     (3) As shown in  FIG. 5A , the valve body engaging member  60 , which is in a condition that the first plate member  61  and the second plate member  62  are confronted to each other, is inserted into an inside of the passage wall surface  152  in such a manner as to be contact with the valve body  30 . 
     (4) The valve body engaging member  60  is pressed toward the pressurizing chamber  113  against the plate spring  80  and is engaged with the engagement groove  153 . 
     (5) As shown in  FIG. 5B , the C-ring  600  is disposed between the valve body  30  and the step surface  66 . 
     The valve body  30  assembled to the housing body  11  is biased toward the valve body engaging member  60  by the plate spring  80 , whereby the valve body is engaged with the valve body engaging member  60 . The position of the valve body  30  is fixed in the passage  151 . 
     As described above, the valve body engaging member  60  is configured in such a manner as to satisfy the above relationship ( 1 ). Since the radius “Rc” is larger than the radius “Rb”, even if the radius “Ra” is larger than the radius “Rc”, the valve body engaging member  60  can be easily and smoothly engaged with the engagement groove  153  with the first and the second plate member  61 ,  62  confronted to each other. 
     When the C-ring  600  is disposed inside of the valve body engaging member  60 , the C-ring  600  exerts a resilient force in its radial outward direction. An outer periphery of the C-ring  600  is firmly in contact with the step side wall  67  and biases the first curved portion  63  of the plate members  61 ,  62  toward the outer wall  155  of the engagement groove  153 . In the present embodiment, since the valve body engaging member  60  and the housing body  11  are configured to satisfy the relationship of “Ra”≦“Rd”, a contacting area between the first curve portion  63  and the outer wall  155  can be made relatively large. 
     Further, since the valve body engaging member  60  and the housing body  11  are configured to satisfy the relationship of “Rc”&lt;“Ra”≦“Rd”, as shown in  FIGS. 5B and 6 , a contacting area between a surface  68  of the valve body engaging member  60  and an annular surface  156  of the engagement groove  153  can be made relatively large. This contacting area is indicated by grid hatching in  FIG. 5B . A circumferential length of the C-ring is about 80% of a circumferential length of the step side wall  67 . 
     As shown in  FIGS. 5B ,  6 A, and  6 C, the C-ring  600  is disposed between the step surface  66  and the valve body  30 . The C-ring  600  has a circular cross section. In a case that a distance between the contacting surface  65  and the step surface  66  is denoted by “t” and a diameter of cross section of the C-ring  600  is denoted by “d”, a relationship of “t”&gt;“d” is established. Thus, the C-ring  600  can be easily positioned between the valve body  30  and the step surface  66 . 
     An operation of the high-pressure pump  10  will be described hereinafter. 
     [Suction Stroke] 
     When the plunger  13  slides down in  FIG. 2 , the coil  71  is deenergized. The suction valve  40  is biased toward the pressurizing chamber  113  by the spring  22 . The suction valve  40  moves away from the suction valve seat  34 . Further, when the plunger  13  slides down, the pressure in the pressurizing chamber  113  is decreased. Thus, the force which the suction valve  40  receives from the fuel in the concave portion  33  becomes larger than the force which the suction valve  40  receives from the fuel in the pressurizing chamber  113 . The force biasing the suction valve  40  away from the suction valve seat  34  is further increased. The suction valve  40  moves until the suction valve  40  is brought in contact with the stopper  50 . The fuel chamber  16  communicates with the pressurizing chamber  113  through the introducing passage  111 , the passage  151 , and the suction passage  112 . The fuel in the fuel chamber  16  is suctioned into the pressurizing chamber  113  through the first passage  121 , the second passage  122 , the intermediate passage  124  and the third passage  123 . The fuel in the intermediate passage  124  can flow into the volume chamber  54  through the communication passage  55 . The pressure in the volume chamber  54  is equal to the pressure in the intermediate passage  124 . 
     [Metering Stroke] 
     When the plunger  13  slides up toward the top dead center from the bottom dead center, the suction valve  40  receives the force from the fuel in the pressurizing chamber  113  so that the suction valve  40  sits on the suction valve seat  34 . Meanwhile, when the coil  71  is deenergized, the needle  49  is biased to the suction valve  40  by the spring  22 . Thus, the movement of the suction valve  40  toward the suction valve seat  34  is restricted by the needle  40 . 
     In the metering stroke, while the coil  71  is deenergized, the suction valve  40  is positioned away from the suction valve seat  34 . The fuel discharged from the pressurizing chamber  113  is returned into the fuel chamber  16  through the third passage  123 , the intermediate passage  124 , the second passage  122  and the first passage  121  in this series. 
     In the metering stroke, when the coil  71  is energized, a magnetic circuit is generated between the fixed core  72 , the flange  75  and the movable core  73 . Magnetic attraction force is generated between the fixed core  72  and the movable core  73 . When this magnetic attraction force exceeds the biasing force of the spring  22 , the movable core  73  and the needle  49  move toward the fixed core  72 . The suction valve  40  moves away from the needle  49  and receives no force from the needle  49 . Consequently, the suction valve  40  sits on the suction valve seat  34 . That is, the suction valve  40  is closed. 
     In the present embodiment, the stopper  50  has the communication passage  55  which connects the intermediate passage  124  and the volume chamber  54 . The pressure in the volume chamber  54  becomes equal to the pressure in the intermediate passage  124 . That is, even if the pressure in the intermediate passages  124  becomes high, the pressure in the intermediate passages  124  does not exceed the pressure in the volume chamber  54 . The suction valve  40  can easily move away from the stopper  50 . Therefore, the suction valve  40  can be made to estrange easily from the cylinder portion  51  of the blade latch  50 . Thereby, the suction valve  40  can be closed at a desired timing. 
     When the suction valve  40  sits on the suction valve seat  34 , the second passage  122  is closed and the fuel flow flowing through the fuel passage  151  is interrupted. Thereby, the metering stroke in which the fuel is discharged from the pressurizing chamber  113  to the fuel chamber  16  is terminated. When the plunger  13  slides up, the fuel quantity returning to the fuel chamber  16  from the pressurizing chamber  113  is adjusted by closing the second passage  122 . The quantity of fuel which will be pressurized in the pressurizing chamber  113  is determined. 
     [Pressurizing Stroke] 
     When the plunger  13  further slides up toward the top dead center with an interruption between the pressurizing chamber  113  and the fuel chamber  16 , the fuel pressure in the pressurizing chamber  113  further increases. When the fuel pressure in the pressurizing chamber  113  exceeds a specified value, the suction valve  92  moves away from the discharge valve seat  95 . Thereby, the discharge valve portion  90  is opened so that the pressurized fuel in the pressurizing chamber  113  is discharged from the high-pressure pump  10  through the discharge passage  114 . The fuel discharged from the high-pressure pump  10  is accumulated in the delivery pipe (not shown) and is supplied to each fuel injector. 
     When the plunger  13  reaches the top dead center, the coil  71  is deenergized and the suction valve  40  is opened again. Further, when the plunger  13  starts sliding down, the pressure in the pressurizing chamber  113  is decreased. Thereby, the fuel is suctioned into the pressurizing chamber  113  from the fuel chamber  16 . 
     It should be noted that the coil  71  may be deenergized when the suction valve  40  is closed so that the fuel pressure in the pressurizing chamber  113  reaches the specified value. When the fuel pressure in the pressurizing chamber  113  is increased, the force biasing the suction valve  40  to be closed becomes larger than the force biasing the suction valve  40  to be opened. Thus, even if the coil  71  is deenergized, the suction valve  40  maintains to be closed. By deenergizing the coil  71 , the power consumption of the electromagnetic driving portion  70  can be reduced. 
     The above suction stroke, the metering stroke and the pressurizing stroke are conducted repeatedly, so that the high-pressure pump  10  pressurizes and discharges the fuel. The discharge quantity of fuel is adjusted by controlling the energization timing of the coil  71 . 
     As described above, according to the present embodiment, the valve body engaging member  60  is comprised of two arc-shaped plate members  61  and  62 , which form ring-shape when confronting to each other. The valve body engaging member  60  is inserted into the engagement groove  153  and is in contact with the valve body  30 . Thereby, the position of the valve body  30  is fixed. The C-ring  600  is firmly in contact with the step side wall  67  and biases the plate members  61 ,  62  toward the outer wall  155  of the engagement groove  153 . Thereby, it is restricted that the valve body engaging member  60  is disengaged from the engagement groove  153 . 
     When assembling the valve body engaging member  60  to the housing body  11 , the plate members  61 ,  62  are inserted into the engagement groove  153  and then the C-ring  600  is disposed inside of the valve body engaging member  60 . Since the valve body engaging member  60  is comprised of two arc-shaped plate members  61 ,  62 , it is unnecessary to elastically deform the valve body engaging member  60  when assembling the valve body engaging member  60  to the engagement groove  153 . Thus, the plate members  61 ,  62  can be made of material having high hardness. Alternatively, the plate members  61 ,  62  can receive heat treating to improve the hardness thereof. The mechanical strength of the valve body engaging member  60  can be improved without deteriorating its assembling work. 
     Furthermore, according to the present embodiment, the valve body  30  can be positioned by the vale body engaging member  60  without utilizing an axial fastening force of a fastening member such as a bolt. Thus, it is unnecessary to configure the valve body engaging member  60  in such a manner as to receive the axial fastening force. The size of the high-pressure pump  10  can be made smaller. 
     In a case the first plate member  61  is confronted to the second plate member  62 , the valve body engaging member  60  has the first curved portion  63  and the second curved portion  64  of which curvature is different from each other. The first curved portion  63  and the second curved portion  64  are alternately formed in circumferential direction at intervals of 90°. The valve body engaging member  60  and the housing body  11  are configured to satisfy the relationship of “Rb”&lt;“Rc”&lt;“Ra”≦“Rd”. 
     Since “Rc” is larger than “Rb”, even if “Ra” is larger than “Rc”, the valve body engaging member  60  can be easily and smoothly engaged with the engagement groove  153  with the first and the second plate member  61 ,  62  confronted to each other. Further, since “Rd” is greater than or equal to “Ra”, the contacting area between the outer periphery of the member  60  and the outer wall  155  can be made relatively large. Thereby, a stress applied to the valve body engaging member  60  can be reduced, and the position of the member  60  in the engagement groove  153  becomes stable. Furthermore, since the relationship of “Rc”&lt;“Ra”≦“Rd” is established, the contacting area between the surface  68  of the valve body engaging member  60  and the flat surface  156  of the engaging groove  153  can be made relatively large. Thereby, even when a large pressure is applied to the contacting surface  65 , the pressure applied to the surface  68  can be reduced. 
     The first and second plate members  61 ,  62  have a step surface  66  at the contacting surface  65  which is in contact with the valve body  30 . The C-ring  600  is disposed between the step surface  66  and the valve body  30 . In a case that a distance between the contacting surface  65  and the step surface  66  is denoted by “t” and a diameter of cross section of the C-ring  600  is denoted by “d”, a relationship of “t”&gt;“d” is established. Thus, the C-ring  600  can be easily positioned between the valve body  30  and the step surface  66 . Further, a clearance is formed between the C-ring  600  and the valve body  30  and/or between the C-ring  600  and the step surface  66 . Even if the contacting surface  65  receives a large pressure, the C-ring  600  is never crushed between the valve body  30  and the valve body engaging member  60 . 
     The hardness of the plate members  61 ,  62  is greater than that of the C-ring  600 . Thus, the durability of the plate members  61 ,  62  can be improved and an elastic force of the C-ring  600  can be suitably established. 
     Second Embodiment 
       FIG. 7  shows a high-pressure pump according to a second embodiment.  FIG. 7  is a cross-sectional view corresponding to a cross-sectional view taken along a line X-X in  FIG. 2 . 
     In the second embodiment, the suction valve  40  and the needle  49  are formed from a single piece. When the moving core  73  is magnetically attracted to the fixed core  72 , the suction valve  40  and the needle  49  move toward the fixed core  72  to be closed. Thus, in the second embodiment, a biasing member biasing the suction valve  40  in its close direction is not necessary. 
     The housing body  11  is provided with a relief-valve portion  200 . The relief-valve portion  200  controls the fuel pressure in the pressurizing chamber  113  when the fuel pressure in the delivery pipe becomes extremely large. The relief-valve portion  200  includes a relief valve  210  and a spring  220  which biases the relief valve  210 . 
     The housing  11  defines a passage  230  therein. A cylindrical passage wall  231  defines the passage  230 . One end of the passage  230  is opened on an outer surface of the housing body  11 . This opening is fluidly closed by a lid member  240 . The other end of the passage  230  communicates with a small-diameter passage  250  of which inner diameter is smaller than that of the passage  230 . A relief-valve seat  232  is defined between the passage  230  and the small-diameter passage  250 . 
     The small-diameter passage  250  communicates with a discharge passage  114 . A passage  260  is connected to the passage  230  at a vicinity of the lid member  240 . The other end of the passage  260  is connected to the pressurizing chamber  113 . Thus, the passage  230  communicates with the fuel outlet  91  through the small-diameter passage  250  and communicates with the pressurizing chamber  113  through the passage  260 . 
     The relief valve  210  is slidably arranged in the passage  230 . The relief valve  210  is made of martensite stainless steel of which hardness is improved by heat treating. The relief valve  210  is comprised of a bottom portion  211  and cylindrical portion  212 . The bottom portion  211  has a seat portion  213 . The seat portion  213  can be in contact with the relief-valve seat  242 . When the relief valve  210  sits on the relief-valve seat  232 , the passage  230  is closed. When the relief valve  210  moves away from the relief-valve seat  232 , the passage  230  is opened. Further, the cylindrical portion  212  has an aperture  214 . 
     A cylindrical stopper  270  is press-inserted into the passage  230 . The stopper  270  is made of austenite stainless steel. The hardness of the stopper  270  is lower than that of the relief valve  210 . The stopper  270  is comprised of a bottom portion  271  and a cylindrical portion  272 . The bottom portion  271  has an aperture  273 . 
     A spring  220  is disposed between the bottom portion  271  of the stopper  270  and the bottom portion  211  of the relief valve  210 . One end of the spring  220  is engaged with the bottom portion  271  and the other end is engaged with the bottom portion  211 . The relief valve  210  is biased toward the relief-valve seat  232  by the spring  220 . 
     When the fuel pressure in the discharge passage  114  exceeds a specified value, the relief valve  210  moves toward the stopper  270 , whereby the relief valve  210  is opened. 
     When the relief-vale body  210  is opened, the fuel in the discharge passage  114  is returned to the pressurizing chamber  113 . Thereby, it is prevented that the fuel in a delivery pipe (not shown) becomes excessively large. 
     The valve body engaging member  60 , the C-ring  600 , the valve body engaging member  60  and the engagement groove  153  have the same configuration as those in the first embodiment. The second embodiment has the substantially the same advantages as the first embodiment. 
     Third Embodiment 
       FIG. 8  shows a part of a high-pressure pump according to a third embodiment.  FIG. 8  is a cross-sectional view showing a discharge valve portion  90 . The third embodiment is different from the second embodiment only in a configuration of the discharge valve portion  90 . 
     The discharge valve portion  90  is comprised of a discharge valve  92 , a spring  94  and a discharge-valve engaging member  930 . The housing body  11  has the discharge passage  114  which is defined by a passage wall surface  940 . 
     Further, the housing body  11  has an annular engagement groove  941  on the passage wall surface  940 . The discharge-valve engaging member  930  is inserted to the engagement groove  941 . The discharge valve  92  is biased toward the discharge valve seat  95  by a spring  94  which is engaged with the discharge-valve engaging member  930 . The discharge valve  92  can reciprocate in the discharge passage  114  between the discharge valve seat  95  and the discharge-valve engaging member  930 . The discharge valve  92  moves away from the discharge valve seat  95  until the discharge valve  92  is confronted to the discharge-valve engaging member  930 . In the third embodiment, it is unnecessary to provide a regulation member  93 , because the discharge-valve engaging member  930  functions as a stopper of the discharge valve  92 . The discharge passage  114  corresponds to a part of a fuel passage of the present invention. The discharge valve  92  corresponds to “an engaged member”, and The discharge-valve engaging member  930  corresponds to “an engaging member” of the present invention. 
     A C-ring  601  is provided inside of the discharge-valve engaging member  930 . The C-ring  601  is made of austenite stainless steel. The C-ring  601  has resilience in its radial outward direction. The C-ring  601  biases the discharge-valve engaging member  930  radially outwardly so that it is prevented that the discharge-valve engaging member  930  is disengaged from the engagement groove  153 . 
     The discharge-valve engaging member  930  is comprised of two arc-shaped plate members  931 ,  932 . These plate members  931 ,  932  are made of martensite stainless steel, and have substantially the same hardness of the discharge valve  92 . The hardness of the plate members  931 ,  932  is greater than that of the C-ring  601 . The first plate member  931  and the second plate member  62  are arc-shaped. In a case that the first plate member  931  is confronted to the second plate member  932 , these plate members  931 ,  932  form an annular shape. The discharge-valve engaging member  930  has the first curved portion and the second curved portion of which curvature is different from each other. The first curved portion and the second curved portion are alternately formed in circumferential direction at intervals of 90°. 
     A relationship between a curvature radius of the first curved portion, a curvature radius of the second curved portion, an inner diameter of the passage wall surface  940 , and an outer diameter of the engagement groove  941  is the same as the relationship between “Ra”, “Rb”, “Rc” and “Rd” in the first embodiment. Thus, the third embodiment has substantially the same advantages as the first embodiment. 
     The first and second plate members  931 ,  932  have a step surface  933 . The C-ring  601  is arranged at the step surface  933 . 
     In the above first and the second embodiment, the regulation member  93  is provided as a stopper of the discharge valve  92 . However, the hardness of the regulation member  93  is lower than that of the discharge valve  92 . If the discharge valve  92  is brought in contact with the regulation member  93  repeatedly, it is likely that the regulation member  93  may be abraded. Meanwhile, in the present embodiment, since the hardness of the discharge valve  92  is substantially equal to that of the discharge-valve engaging member  930 , an abrasion of the discharge-valve engaging member  930  is restricted. 
     Fourth Embodiment 
       FIG. 9  shows a part of a high-pressure pump according to a fourth embodiment.  FIG. 9  is a cross-sectional view showing a relief valve portion  200 . The fourth embodiment is different from the second embodiment only in a configuration of the relief valve portion  200 . 
     The relief valve portion  200  is comprised of a relief valve  210 , a spring  220  and a relief-valve engaging member  280 . The housing body  11  has a passage  230  which is defined by a passage wall surface  231 . Further, the housing body  11  has an annular engagement groove  232  on the passage wall surface  231 . The relief-valve engaging member  280  is inserted into the engagement groove  232  between the regulation member  270  and the relief valve  210 . The regulation member  270  is in contact with the relief-valve engaging member  280 . 
     The relief valve  210  is biased toward a relief valve seat  232  by the spring  220  which is engaged with the regulation member  270 . The relief valve  210  can reciprocate in the passage  230  between the relief valve seat  232  and the relief-valve engaging member  280 . The relief valve  210  moves away from the relief valve seat  232  until the relief valve  210  is confronted to the relief-valve engaging member  280 . The relief-valve engaging member  280  functions as a stopper of the relief valve  210 . The passage  230  corresponds to a part of a fuel passage of the present invention. The relief valve  210  corresponds to “an engaged member”, and the relief-valve engaging member  280  corresponds to “an engaging member” of the present invention. 
     A C-ring  602  is provided inside of the relief-valve engaging member  280 . The C-ring  602  is made of austenite stainless steel. The C-ring  602  has resilience in its radial outward direction. The C-ring  602  biases the relief-valve engaging member  280  radially outwardly so that it is prevented that the relief-valve engaging member  280  is disengaged from the engagement groove  232 . 
     The relief-valve engaging member  280  is comprised of two arc-shaped plate members  281 ,  282 . These plate members  281 ,  282  are made of martensite stainless steel, and have substantially the same hardness of the relief valve  210 . 
     The hardness of the plate members  281 ,  282  is greater than that of the C-ring  602 . The first plate member  281  and the second plate member  282  are arc-shaped. In a case that the first plate member  281  is confronted to the second plate member  282 , these plate members  281 ,  282  form an annular shape. The relief-valve engaging member  280  has the first curved portion and the second curved portion of which curvature is different from each other. The first curved portion and the second curved portion are alternately formed in circumferential direction at intervals of 90°. 
     A relationship between a curvature radius of the first curved portion, a curvature radius of the second curved portion, an inner diameter of the passage wall surface  231 , and an outer diameter of the engagement groove  232  is the same as the relationship between “Ra”, “Rb”, “Rc” and “Rd” in the first embodiment. Thus, the fourth embodiment has substantially the same advantages as the first embodiment. 
     The first and second plate members  281 ,  282  have a step surface  283 . The C-ring  602  is arranged at the step surface  283 . Therefore, it is restricted that the C-ring  602  is disengaged from the relief-valve engaging member  280 . 
     In the present embodiment, since the hardness of the relief valve  210  is substantially equal to that of the relief-valve engaging member  280 , an abrasion of the relief-valve engaging member  280  is restricted. 
     Fifth Embodiment 
       FIG. 10  shows a part of a high-pressure pump according to a fifth embodiment.  FIG. 10  is a cross-sectional view showing a valve body engaging member  60 . The fifth embodiment is different from the first embodiment only in a configuration of the valve body engaging member  60 . 
     The valve body engaging member  60  has a circular groove  69  on its inner peripheral surface. A C-ring  600  is inserted into the circular groove  69 . Thereby, it is restricted that the C-ring  600  is disengaged from the circular groove  69 . 
     The circular groove  69  is arranged at center position in an axial direction of the valve body engaging member  60 . Thus, the C-ring  600  uniformly biases the first and the second plate members  61 ,  62  toward the outer wall  155 . The position of the plate members  61 ,  62  in the engagement groove  153  becomes stable. 
     Other Embodiment 
     The above first to fourth embodiments can be combined suitably. The configuration of the valve body engaging member  60  of the fifth embodiment can be applied to the second to fourth embodiments. 
     The engaging member can be comprised of three or more arc-shape plate members. 
     The engaging member can have a third curved portion between the first curved portion and the second curved portion. The third curved portion has a curvature radius which is intermediate between the curvature radius of the first curved portion and the second curved portion. The curvature radius is smoothly changed from the first curved portion to the second curved portion. 
     The C-ring may have a rectangular shape of cross section. A contacting area of the C-ring can be made large. The position of the engaging member in the engagement groove becomes more stable. 
     In the above embodiments, the valve is a normally-open valve. A normally-close valve can be used. 
     The engaging member can be utilized to various devices other than a high-pressure pump. 
     The present invention is not limited to the embodiments mentioned above, and can be applied to various embodiments.