JP2010156258A - High pressure pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high pressure pump securing the favorable seating of a valve member on a valve seat and stabling a delivery quantity. <P>SOLUTION: The pump includes a housing body 11 including a pressurizing chamber 113 pressurizing fuel and a fuel passage 100 introducing fuel to the pressurizing chamber 113, a valve body 30 disposed in the fuel passage 100 and a valve seat 34 on a pressurizing chamber 113 sidewall surface, a valve member 40 including a shaft 41 and a head 42 and intermitting the flow of fuel flowing in the fuel passage 100 by making the head 42 seated on and separated from the valve seat 34, a stopper 50 regulating the movement of the valve member 40 to an valve open direction, a needle 60 provided in such a manner that one end can abut on the shaft 41 and can move in the same direction as a moving direction of the valve member 40, and an electromagnetic drive part 70 capable of attracting the needle 60 in a valve close direction of the valve member 40. The valve body 30 includes a first guide 35 including a first insertion hole 351 slidably guiding the shaft 41 of the valve member 40. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a high-pressure pump that pressurizes fuel sucked into a pressurizing chamber by reciprocating movement of a plunger.

  Conventionally, a high-pressure pump that pressurizes and discharges fuel sucked into a pressurizing chamber by a reciprocating movement of a plunger is known. For example, in the case of the high-pressure pump disclosed in Patent Document 1, a valve member for adjusting the flow rate of fuel supplied to the pressurizing chamber is provided in the middle of the fuel passage connected to the pressurizing chamber. The valve member is driven by an electromagnetic drive unit. The electromagnetic drive unit reciprocates the valve member in the direction of seating on or away from the valve seat via the needle.

By the way, in the high-pressure pump of Patent Document 1, a passage through which fuel flows is formed on the outer periphery of the needle. That is, a gap corresponding to the passage is formed between the outer peripheral wall of the needle and the inner peripheral wall of the member through which the needle is inserted. For this reason, when the electromagnetic drive unit reciprocates the valve member via the needle, the radial position of the needle shaft may become unstable. As a result, during operation of the electromagnetic drive unit, the contact portion between the needle and the valve member is displaced, leading to unstable seating of the valve member on the valve seat. As a result, the flow rate of the fuel supplied to the pressurizing chamber or the fuel discharged from the high pressure pump may vary.
JP-T-2002-521616

  An object of the present invention is to provide a high-pressure pump that maintains good seating of a valve member on a valve seat and has a stable discharge amount.

  According to the first aspect of the present invention, a plunger that is reciprocally movable, a pressurizing chamber in which fuel is pressurized by the plunger, a housing having a fuel passage that guides the fuel to the pressurizing chamber, and a fuel passage, By having a valve body having a valve seat on the chamber side wall surface, a shaft portion, and an umbrella portion connected to a pressurizing chamber side end portion of the shaft portion, the umbrella portion is seated on the valve seat or separated from the valve seat A valve member that interrupts the flow of fuel flowing through the fuel passage, a stopper that is provided on the pressure chamber side of the valve member and restricts movement of the valve member in the valve opening direction, and is provided between the stopper and the valve member A first urging member that urges the valve member in the valve closing direction, and one end of the first urging member can be brought into contact with an end portion of the shaft portion opposite to the umbrella portion, and when the valve member is opened or closed A needle provided to be movable in the same direction as the moving direction, and the needle is urged in the valve opening direction of the valve member It comprises a second biasing member, and an electromagnetic driving unit having a coil portion capable attracted to either the valve closing direction or the valve opening direction of the needle valve member. The valve body includes a first guide portion having a first insertion hole that slidably guides the shaft portion of the valve member. Therefore, when the valve member is moved in the valve opening direction or the valve closing direction via the needle by the electromagnetic drive unit, the valve member is guided to reciprocate in the axial direction by the first guide unit. Thereby, the valve member can be stably seated or separated from the valve seat without moving in the radial direction. Therefore, the flow rate of the fuel supplied to the pressurizing chamber and the flow rate of the fuel discharged from the high pressure pump can be stabilized.

  According to a second aspect of the present invention, the electromagnetic drive section includes a second guide section having a second insertion hole for slidably guiding the needle. Therefore, when the valve member is moved in the valve opening direction or the valve closing direction via the needle by the electromagnetic drive unit, the needle is guided to reciprocate in the axial direction by the second guide unit. Thereby, the needle can be stably brought into contact with the valve member without moving in the radial direction. As a result, the reciprocating movement of the valve member in contact with the needle is stabilized, and the valve member can be more stably seated or separated from the valve seat.

  In the invention according to claim 3, the contact portion between the shaft portion and the needle is always between the second guide portion side end portion of the first guide portion and the first guide portion side end portion of the second guide portion. It is provided so that it may be located in. Thus, when the shaft portion and the needle reciprocate, the respective contact side end portions are within the moving range up to the end surface of the opposing second guide portion or the front surface of the first guide portion. Therefore, even when the shaft member and the needle are assembled in a non-coaxial state, when the valve member and the needle are reciprocally moved, the respective abutting side end portions are opposed to the end surface of the opposing second guide portion or the second one. There is no contact with the end face of one guide part. As a result, the movement of the shaft portion and the needle is not hindered by the opposing end surfaces. Therefore, regardless of the assembled state of the valve member and the needle, the needle can be properly brought into contact with the shaft portion. Therefore, when assembling the valve member and the needle, high accuracy such as accurate coaxial assembly is not required, and the assembly can be facilitated.

  In the invention described in claim 4, the shaft portion and the needle are different in the outer diameter of the end portions in contact with each other. That is, the contact area between the shaft portion and the needle can be the area of the end surface of the shaft portion and the needle whose outer diameter is smaller. As a result, when the needle abuts on the shaft portion, the contact area between the shaft portion and the needle can be made substantially constant even if the shaft portion and the needle shaft are out of alignment. As a result, the force applied by the needle to the shaft portion is stabilized, and the reciprocating movement of the valve member can be further stabilized.

  Further, since the shaft portion and the needle have different outer diameters at the end portions in contact with each other, the first insertion hole through which the shaft portion is slidably inserted and the needle are slidably inserted. The diameter of the two insertion holes is also different. Thereby, for example, when the shaft portion and the needle “reciprocate, the respective contact-side end portions exceed the end surface of the second guide portion or the end surface of the first guide portion, and the second insertion hole or the first Even if it is "a structure that enters the insertion hole" and "it is assembled in a non-coaxial state", the respective contact-side end portions are on the end surface of the second guide portion or the end surface of the first guide portion. There is no contact. Therefore, when assembling the valve member and the needle, high accuracy such as accurate coaxial assembly is not required, and assembly can be facilitated. Moreover, according to the said structure, the freedom degree of design can be raised regarding the axial direction length of an axial part and a needle, and the axial direction position of the contact location of an axial part and a needle.

  In the invention according to claim 5, the needle side end of the shaft portion is formed in a tapered shape whose outer diameter decreases toward the needle side. That is, the outer diameter of the needle side end portion of the shaft portion is smaller than the outer diameter of the portion other than the needle side end portion of the shaft portion. Therefore, for example, even if the outer diameter of the portion other than the needle side end portion of the shaft portion is equal to the outer diameter of the needle, the contact area between the shaft portion and the needle is the area of the needle side end surface of the shaft portion, That is, the area can be smaller than the area of the end surface on the side of the shaft portion of the needle. As a result, when the needle abuts on the shaft portion, the contact area between the shaft portion and the needle can be made substantially constant even if the shaft portion and the needle shaft are out of alignment. As a result, the force applied by the needle to the shaft portion is stabilized, and the reciprocating movement of the valve member can be further stabilized.

  In the invention according to claim 6, the shaft portion side end portion of the needle is formed in a tapered shape whose outer diameter decreases toward the shaft portion side. In other words, the outer diameter of the needle-side end surface of the needle is smaller than the outer diameter of the portion other than the needle-side end portion of the needle. Therefore, for example, even if the outer diameter of the portion other than the end portion on the shaft portion side of the needle is equal to the outer diameter of the shaft portion, the contact area between the shaft portion and the needle is the area of the end surface on the shaft portion side of the needle. That is, the area can be smaller than the area of the end surface on the needle side of the shaft portion. As a result, when the needle abuts on the shaft, the contact area between the shaft and the needle can be made substantially constant even if the shaft and the shaft of the needle are in a state of being displaced. As a result, the force applied by the needle to the shaft portion is stabilized, and the reciprocating movement of the valve member can be further stabilized.

  In the invention according to claim 7, either the needle side end surface of the shaft portion or the shaft side end surface of the needle is formed in a spherical shape. Therefore, when the needle comes into contact with the shaft portion, the contact area between the shaft portion and the needle is extremely small. Thereby, even if it is in the state which the axis | shaft part and the axis | shaft of the needle shifted | deviated at this time, the contact area of a shaft part and a needle can be made substantially constant. As a result, the force applied by the needle to the shaft portion is stabilized, and the reciprocating movement of the valve member can be further stabilized.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings. Note that, in a plurality of embodiments, substantially the same components are denoted by the same reference numerals, and description thereof is omitted.
(First embodiment)
A high-pressure pump according to a first embodiment of the present invention is shown in FIGS. The high-pressure pump 10 is a fuel pump that supplies fuel to, for example, an injector of a diesel engine or a gasoline engine.

As shown in FIG. 2, the high-pressure pump 10 includes a housing body 11, a cover 12, a valve body 30, a valve member 40, a stopper 50, a spring 21, a needle 60, a spring 22, and an electromagnetic drive unit 70.
The housing main body 11 and the cover 12 constitute a “housing” in the claims. The housing body 11 is made of, for example, martensitic stainless steel. The housing body 11 forms a cylindrical cylinder 14. A plunger 13 is supported on the cylinder 14 of the housing body 11 so as to be reciprocally movable in the axial direction.

  The housing body 11 forms an introduction passage 111, a suction passage 112, a pressurizing chamber 113, a discharge passage 114, and the like. The housing body 11 has a cylindrical portion 15. The cylinder portion 15 forms a passage 151 that communicates the introduction passage 111 and the suction passage 112 therein. The cylinder part 15 is formed substantially perpendicularly to the central axis of the cylinder 14, and the inner diameter changes midway. The housing body 11 has a step surface 152 at a portion where the inner diameter changes in the cylindrical portion 15. A valve body 30 is provided in the passage 151 formed in the cylindrical portion 15.

  A fuel chamber 16 is formed between the housing body 11 and the cover 12. A fuel inlet (not shown) that communicates with the fuel chamber 16 is formed in the housing body 11. Fuel is supplied to the fuel chamber 16 from a fuel tank by a low-pressure fuel pump (not shown) through the fuel inlet. The introduction passage 111 communicates the fuel chamber 16 and a passage 151 formed on the inner peripheral side of the cylindrical portion 15. One end of the suction passage 112 communicates with the pressurizing chamber 113. The other end of the suction passage 112 opens to the inner peripheral side of the step surface 152. The introduction passage 111 and the suction passage 112 are connected via the inner peripheral side of the valve body 30 as shown in FIG. As shown in FIG. 2, the pressurizing chamber 113 communicates with the discharge passage 114 on the side opposite to the suction passage 112. Here, the introduction passage 111, the passage 151, and the suction passage 112 constitute a “fuel passage” in the claims. In the present embodiment, the “fuel passage” is indicated by the fuel passage 100.

  The plunger 13 is supported by the cylinder 14 of the housing body 11 so as to be capable of reciprocating in the axial direction. The pressurizing chamber 113 is formed on one end side in the reciprocating direction of the plunger 13. A head 17 provided on the other end side of the plunger 13 is coupled to a spring seat 18. A spring 19 is provided between the spring seat 18 and the housing body 11. The spring seat 18 is biased toward the cam (not shown) by the biasing force of the spring 19. The plunger 13 is driven to reciprocate by contacting a cam via a tappet (not shown).

  The spring 19 has one end in contact with the housing body 11 and the other end in contact with the spring seat 18. The spring 19 has a force that extends in the axial direction. As a result, the spring 19 biases a tappet (not shown) to the cam side via the spring seat 18. The outer peripheral surface of the plunger 13 on the head 17 side and the inner peripheral surface of the housing main body 11 forming the cylinder 14 that accommodates the plunger 13 are sealed in a liquid-tight manner by an oil seal 23. The oil seal 23 prevents oil from entering the pressurizing chamber 113 from the engine and prevents fuel from flowing out from the pressurizing chamber 113 to the engine.

  The discharge valve portion 90 that forms the fuel outlet 91 is provided on the discharge passage 114 side of the housing body 11. The discharge valve unit 90 intermittently discharges the fuel pressurized in the pressurizing chamber 113. The discharge valve unit 90 includes a check valve 92, a regulating member 93, and a spring 94. The check valve 92 is formed in a bottomed cylindrical shape including a bottom portion 921 and a cylindrical portion 922 that extends in a cylindrical shape from the bottom portion 921 toward the anti-pressurization chamber 113, and is provided so as to be capable of reciprocating in the discharge passage 114. The regulating member 93 is formed in a cylindrical shape and is fixed to the housing body 11 that forms the discharge passage 114. One end of the spring 94 is in contact with the regulating member 93, and the other end is in contact with the cylindrical portion 922 of the check valve 92. The check valve 92 is biased toward the valve seat 95 formed by the housing body 11 by the biasing force of the spring 94. The check valve 92 closes the discharge passage 114 when the end portion on the bottom 921 side is seated on the valve seat 95, and opens the discharge passage 114 when the end portion is separated from the valve seat 95. When the check valve 92 moves to the side opposite to the valve seat 95, the movement of the check valve 92 is restricted by the end of the cylinder portion 922 on the side opposite to the bottom 921 contacting the restriction member 93.

  When the pressure of the fuel in the pressurizing chamber 113 increases, the force received by the check valve 92 from the fuel on the pressurizing chamber 113 side increases. The force received by the check valve 92 from the fuel on the pressurizing chamber 113 side is larger than the sum of the biasing force of the spring 94 and the fuel received from the fuel on the downstream side of the valve seat 95, that is, the fuel in the delivery pipe (not shown). As a result, the check valve 92 is separated from the valve seat 95. As a result, the fuel in the pressurizing chamber 113 is discharged from the fuel outlet 91 via the discharge passage 114, that is, the through hole 923 formed in the cylindrical portion 922 of the check valve 92 and the inner side of the cylindrical portion 922. Is discharged to the outside.

  On the other hand, when the pressure of the fuel in the pressurizing chamber 113 decreases, the force that the check valve 92 receives from the fuel on the pressurizing chamber 113 side decreases. When the force received by the check valve 92 from the fuel on the pressurizing chamber 113 side becomes smaller than the sum of the urging force of the spring 94 and the force received from the fuel on the downstream side of the valve seat 95, the check valve 92 is Sitting on 95. As a result, fuel in a delivery pipe (not shown) is prevented from flowing into the pressurizing chamber 113 via the discharge passage 114.

  The valve body 30 is fixed to the housing body 11 as shown in FIG. The valve body 30 is fixed to the inside of the passage 151 of the housing body 11 by, for example, press fitting and a locking member 20. That is, the valve body 30 is provided in the middle of the passage 151 constituting the fuel passage 100. The valve body 30 is formed in a bottomed cylindrical shape including a bottom portion 31 and a cylindrical portion 32 that extends from the bottom portion 31 toward the pressurizing chamber 113.

The valve body 30 has a recess 33 that is recessed toward the anti-pressurization chamber 113 on the pressurization chamber 113 side of the bottom 31. A valve seat 34 is formed on the outer edge of the recess 33 on the wall surface of the bottom 31 on the pressurizing chamber 113 side. That is, the valve body 30 has a valve seat 34 on the side wall surface of the pressurizing chamber 113. The valve seat 34 is formed in a tapered shape that forms a predetermined angle with respect to the axis of the valve body 30.
The valve body 30 has a first guide portion 35 at the center of the bottom portion 31. The 1st guide part 35 is formed so that it may protrude in the cylinder shape from the center part of the bottom part 31 to the non-recessed part 33 side. The valve body 30 has a first insertion hole 351 that connects the wall surface forming the recess 33 of the first guide portion 35 and the wall surface on the opposite recess 33 side. Further, on the outer peripheral side of the first insertion hole 351 in the bottom portion 31, a first passage 121 that connects the wall surface that forms the recess 33 and the wall surface on the opposite recess 33 side is formed. A plurality of first passages 121 are formed in the circumferential direction with respect to the axis of the valve body 30.

  The valve member 40 includes a substantially cylindrical shaft portion 41 and a substantially disk-shaped umbrella portion 42 connected to the end portion of the shaft portion 41 on the pressurizing chamber 113 side. The valve member 40 has a protruding portion 43 that protrudes in a cylindrical shape from the outer edge of the umbrella portion 42 toward the opposite shaft portion 41 side. The valve member 40 is provided such that the shaft portion 41 is inserted into the first insertion hole 351 of the first guide portion 35 and can reciprocate in the axial direction of the shaft portion 41 inside the valve body 30. The wall surface on the valve seat 34 side of the umbrella portion 42 corresponds to the shape of the valve seat 34 and is formed in a tapered shape that forms a predetermined angle with respect to the shaft of the shaft portion 41. The valve member 40 reciprocates, so that the umbrella portion 42 is seated on the valve seat 34 or is separated from the valve seat 34 to interrupt the flow of fuel flowing through the fuel passage 100. Further, the valve member 40 forms an annular second passage 122 between the valve member 40 and the valve seat 34 when the umbrella portion 42 is separated from the valve seat 34.

  The diameter of the first insertion hole 351 of the first guide part 35 is substantially the same as the diameter of the shaft part 41 of the valve member 40 or slightly larger than the diameter of the shaft part 41. Thus, the valve member 40 reciprocates inside the valve body 30 while the outer wall of the shaft portion 41 slides on the wall surface of the first guide portion 35 that forms the first insertion hole 351. Therefore, when the valve member 40 reciprocates, the reciprocating movement is guided by the first guide portion 35.

  The shaft portion 41 has a small-diameter portion 411 that is recessed in the radially inward direction from the outer peripheral wall in the middle of the axial direction. As a result, the contact area between the shaft portion 41 and the first guide portion 35 is smaller than when the shaft portion 41 does not have the small diameter portion 411. Therefore, when the valve member 40 reciprocates, resistance due to sliding between the shaft portion 41 and the first guide portion 35 can be reduced. At the same time, the small diameter portion 411 also has a role of lubricating the sliding portion of the shaft portion 41.

  A substantially annular fuel reservoir 412 is formed between the small diameter portion 411 and the inner peripheral wall of the first guide portion 35 forming the first insertion hole 351. The fuel on the concave portion 33 side of the first guide portion 35 and the fuel on the counter recess portion 33 side of the first guide portion 35 form the outer peripheral wall of the shaft portion 41 and the inner peripheral wall of the first guide portion 35 that forms the first insertion hole 351. The fuel flows into and is held in the fuel reservoir 412. Therefore, when the valve member 40 reciprocates, the fuel in the fuel pool 412 adheres to the inner peripheral wall of the first guide portion 35. Thereby, resistance due to sliding between the shaft portion 41 and the first guide portion 35 can be further reduced.

  The stopper 50 is provided on the pressure member 113 side of the valve member 40. The stopper 50 includes a cylindrical portion 51, a bottom portion 52 that closes an end portion of the cylindrical portion 51 on the counter valve member 40 side, and an annular extended portion 53 that is formed on a radially outer side of the bottom portion 52. The stopper 50 is fixed to the valve body 30 by welding the outer peripheral wall of the extended portion 53 to the inner peripheral wall of the cylindrical portion 32 of the valve body 30.

  A spring 21 as a first biasing member is provided between the stopper 50 and the valve member 40. One end of the spring 21 is in contact with the bottom 52 and the other end of the spring 21 is in contact with the umbrella portion 42 of the valve member 40. The spring 21 has a force extending in the axial direction, and biases the valve member 40 toward the counter stopper 50 side, that is, in the valve closing direction.

  The end portion on the valve member 40 side of the tubular portion 51 of the stopper 50 and the end portion on the stopper 50 side of the protruding portion 43 of the valve member 40 can contact each other. The stopper 50 forms a volume chamber 54 surrounded by the valve member 40, the inner wall of the cylindrical portion 51, and the bottom portion 52 when the valve member 40 contacts the stopper 50. At this time, the stopper 50 restricts the movement of the valve member 40 toward the pressurizing chamber 113, that is, in the valve opening direction.

When the protruding portion 43 of the valve member 40 is in contact with the cylindrical portion 51 of the stopper 50, the stopper 50 closes the opening of the protruding portion 43 on the pressurizing chamber 113 side. Thereby, at this time, the fuel traveling from the pressurizing chamber 113 side to the valve member 40 side is alleviated from colliding with the valve member 40.
A third passage 123 that connects the wall surface on the pressurizing chamber 113 side and the wall surface on the anti-pressurizing chamber 113 side of the expanding portion 53 is formed in the expanding portion 53 of the stopper 50. A plurality of third passages 123 are formed in the circumferential direction with respect to the axis of the stopper 50.

Between the second passage 122 and the third passage 123, a substantially annular intermediate passage 124 surrounded by the inner peripheral wall of the cylindrical portion 32 of the valve body 30 and the outer peripheral wall of the cylindrical portion 51 of the stopper 50 is formed. Yes.
A tube 55 that connects the volume chamber 54 and the intermediate passage 124 is formed in the cylindrical portion 51 of the stopper 50.

  The first passage 121, the second passage 122, the third passage 123, and the intermediate passage 124 described above are included in the passage 151 formed in the housing body 11, respectively. That is, the fuel passage 100 includes a first passage 121, a second passage 122, a third passage 123, and an intermediate passage 124. Thus, when the fuel moves from the fuel chamber 16 side to the pressurizing chamber 113 side, the fuel flows through the first passage 121, the second passage 122, the intermediate passage 124, and the third passage 123 in this order. On the other hand, when the fuel goes from the pressurizing chamber 113 side to the fuel chamber 16 side, the fuel flows through the third passage 123, the intermediate passage 124, the second passage 122, and the first passage 121 in this order.

  As shown in FIG. 2, the electromagnetic drive unit 70 includes a coil 71, a fixed core 72, a movable core 73, a flange 75, and the like. The coil 71 is wound around a spool 78 made of resin, and generates a magnetic field when energized. The fixed core 72 is made of a magnetic material. The fixed core 72 is accommodated on the inner peripheral side of the coil 71. The movable core 73 is made of a magnetic material. The movable core 73 is disposed to face the fixed core 72. The movable core 73 is accommodated on the inner peripheral side of the cylindrical member 79 and the flange 75 made of a nonmagnetic material so as to be capable of reciprocating in the axial direction. The cylindrical member 79 prevents a magnetic short circuit between the fixed core 72 and the flange 75.

  The flange 75 is made of a magnetic material. As shown in FIG. 1, the flange 75 is attached to the cylindrical portion 15 of the housing body 11. As a result, the flange 75 holds the electromagnetic drive unit 70 on the housing body 11 and closes the end portion of the cylindrical portion 15. The flange 75 has the 2nd guide part 76 formed in the cylinder shape in the center part. The second guide portion 76 has a second insertion hole 761 that communicates the valve body 30 side and the counter valve body 30 side of the flange 75.

  The needle 60 is formed in a substantially cylindrical shape, and is inserted into a second insertion hole 761 formed in the second guide portion 76 of the flange 75. The needle 60 is provided so as to be capable of reciprocating in the axial direction inside the second insertion hole 761. The diameter of the second insertion hole 761 is substantially the same as the diameter of the needle 60 or slightly larger than the diameter of the needle 60. As a result, the needle 60 reciprocates while the outer wall slides on the wall surface of the second guide portion 76 that forms the second insertion hole 761. Therefore, when the needle 60 reciprocates, the reciprocating movement is guided by the second guide portion 76.

  The needle 60 has a substantially planar wall surface 61 formed by chamfering a part of the outer peripheral wall. In this way, by chamfering a part of the outer peripheral wall of the needle 60, the contact area between the needle 60 and the second guide portion 76 is reduced. Thereby, the resistance by sliding with the needle 60 and the 2nd guide part 76 can be reduced.

  A gap 62 is formed between the wall surface 61 of the needle 60 and the inner peripheral wall of the second guide portion 76 that forms the second insertion hole 761. Therefore, the fuel on the valve body 30 side of the flange 75 can flow to the counter valve body 30 side of the flange 75 via the gap 62. Thereby, the pressure of the valve body 30 side and the counter valve body 30 side of the flange 75 becomes substantially the same. The gap 62 also functions as an air vent passage for air accumulated around the movable core 73.

  One end of the needle 60 is press-fitted or welded to the movable core 73 so as to be integrated with the movable core 73. In addition, the end surface 63 formed at the other end of the needle 60 can abut on the end surface 45 formed at the end of the shaft 41 of the valve member 40 on the side opposite to the umbrella portion 42. The needle 60 is movable in the same direction as the movement direction when the valve member 40 is opened or closed.

  A spring 22 as a second biasing member is provided between the fixed core 72 and the movable core 73. The spring 22 biases the movable core 73 toward the valve member 40 side. The force with which the spring 22 biases the movable core 73 is larger than the force with which the spring 21 biases the valve member 40. That is, the spring 22 urges the movable core 73 and the needle 60 against the urging force of the spring 21 in the valve member 40 side, that is, in the valve opening direction of the valve member 40. Thereby, when the coil 71 is not energized, the fixed core 72 and the movable core 73 are separated from each other. Therefore, when the coil 71 is not energized, the needle 60 integral with the movable core 73 moves to the valve member 40 side by the biasing force of the spring 22, and the valve member 40 is separated from the valve seat 34 of the valve body 30. ing. The coil 71, the fixed core 72, the movable core 73, the flange 75, the spool 78, and the cylindrical member 79 of the electromagnetic drive unit 70 constitute a “coil unit” in the claims.

Next, the operation of the high-pressure pump 10 having the above configuration will be described.
(1) Suction stroke When the plunger 13 moves downward in FIG. 2, energization of the coil 71 is stopped. Therefore, the valve member 40 is urged toward the pressurizing chamber 113 by the needle 60 integrated with the movable core 73 receiving the force from the spring 22 of the electromagnetic drive unit 70. As a result, the valve member 40 is separated from the valve seat 34 of the valve body 30. Further, when the plunger 13 moves downward in FIG. 2, the pressure in the pressurizing chamber 113 decreases. Therefore, the force that the valve member 40 receives from the fuel on the concave portion 33 side is larger than the force that is received from the fuel on the pressurization chamber 113 side. As a result, a force is applied to the valve member 40 in a direction away from the valve seat 34, and the valve member 40 is separated from the valve seat 34. The valve member 40 moves until the protruding portion 43 comes into contact with the cylindrical portion 51 of the stopper 50. When the valve member 40 is separated from the valve seat 34, that is, is opened, the fuel chamber 16 communicates with the pressurizing chamber 113 via the introduction passage 111, the passage 151, and the suction passage 112. Therefore, the fuel in the fuel chamber 16 is sucked into the pressurizing chamber 113 via the first passage 121, the second passage 122, the intermediate passage 124, and the third passage 123 in this order. At this time, the valve member 40 is in contact with the stopper 50, so that the opening on the pressurizing chamber 113 side of the protrusion 43 is closed by the stopper 50.

(2) Metering stroke When the plunger 13 rises from the bottom dead center toward the top dead center, the flow of fuel discharged from the pressurizing chamber 113 to the valve member 40 side, that is, the fuel chamber 16 side causes the valve member 40 to A force is applied in the direction of seating on the valve seat 34 from the fuel on the pressurizing chamber 113 side. However, when the coil 71 is not energized, the needle 60 is biased toward the valve member 40 by the biasing force of the spring 22. Therefore, the movement of the valve member 40 toward the valve seat 34 is restricted by the needle 60. In the valve member 40, the opening on the pressurizing chamber 113 side of the protrusion 43 is closed by the stopper 50. Thereby, the flow of the fuel discharged from the pressurizing chamber 113 to the fuel chamber 16 side does not directly collide with the valve member 40. Therefore, the force in the valve closing direction applied to the valve member 40 by the flow of fuel is alleviated. As a result, the valve member 40 maintains a state of being separated from the valve seat 34 while energization of the coil 71 is stopped. As a result, the fuel discharged from the pressurizing chamber 113 as the plunger 13 is lifted is opposite to the case where the fuel is sucked into the pressurizing chamber 113 from the fuel chamber 16, the third fuel passage 123, the intermediate passage 124, and the second passage 122. And it returns to the fuel chamber 16 via the 1st channel | path 121 in this order.

  When the coil 71 is energized during the metering process, a magnetic circuit is formed in the fixed core 72, the flange 75, and the movable core 73 by the magnetic field generated in the coil 71. As a result, a magnetic attractive force is generated between the fixed core 72 and the movable core 73 that are separated from each other. When the magnetic attractive force generated between the fixed core 72 and the movable core 73 becomes larger than the urging force of the spring 22, the movable core 73 moves to the fixed core 72 side. Therefore, the needle 60 integrated with the movable core 73 also moves to the fixed core 72 side. When the needle 60 moves to the fixed core 72 side, the valve member 40 and the needle 60 are separated from each other, and the valve member 40 does not receive a force from the needle 60. As a result, the valve member 40 moves to the valve seat 34 side by the biasing force of the spring 21 and the force in the valve closing direction applied to the valve member 40 by the flow of fuel discharged from the pressurizing chamber 113 to the fuel chamber 16 side. To do.

  When the valve member 40 moves to the valve seat 34 side and the valve member 40 is seated on the valve seat 34, that is, the valve is closed, the second passage 122 is closed and the flow of the fuel flowing through the fuel passage 100 is shut off. . Thus, the metering process for discharging the fuel from the pressurizing chamber 113 to the fuel chamber 16 is completed. When the plunger 13 moves up, the amount of fuel returned from the pressurizing chamber 113 to the fuel chamber 16 is adjusted by closing the second passage 122, that is, between the pressurizing chamber 113 and the fuel chamber 16. As a result, the amount of fuel pressurized in the pressurizing chamber 113 is determined.

(3) Pressurization stroke When the plunger 13 further rises toward the top dead center in a state where the pressurization chamber 113 and the fuel chamber 16 are closed, the fuel pressure in the pressurization chamber 113 rises. When the pressure of the fuel in the pressurizing chamber 113 becomes equal to or higher than a predetermined pressure, the pressure is reversed against the biasing force of the spring 94 of the discharge valve portion 90 and the force received by the check valve 92 from the fuel downstream of the valve seat 95. The stop valve 92 is separated from the valve seat 95. As a result, the discharge valve section 90 is opened, and the fuel pressurized 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 supplied to a delivery pipe (not shown), accumulated, and supplied to the injector.

When the plunger 13 moves to the top dead center, the energization to the coil 71 is stopped, and the valve member 40 is separated from the valve seat 34 again. At this time, the plunger 13 again moves downward in FIG. 2, and the fuel pressure in the pressurizing chamber 113 decreases. As a result, fuel is sucked into the pressurizing chamber 113 from the fuel chamber 16.
When the valve member 40 is closed and the fuel pressure in the pressurizing chamber 113 rises to a predetermined value, the energization of the coil 71 may be stopped. When the pressure of the fuel in the pressurizing chamber 113 increases, the force received in the direction in which the valve member 40 is seated on the valve seat 34 by the fuel on the pressurizing chamber 113 side is larger than the force that the valve member 40 receives in the direction in which the valve member 40 moves away from the valve seat 34. Become. Therefore, even when energization of the coil 71 is stopped, the valve member 40 maintains the seated state on the valve seat 34 by the force received from the fuel on the pressurizing chamber 113 side. Thus, by stopping energization of the coil 71 at a predetermined time, the power consumption of the electromagnetic drive unit 70 can be reduced.

By repeating the steps (1) to (3), the high-pressure pump 10 pressurizes and discharges the sucked fuel. The fuel discharge amount is adjusted by controlling the timing of energizing the coil 71 of the electromagnetic drive unit 70.
In the present embodiment, as shown in FIG. 1, when energization of the coil 71 of the electromagnetic drive unit 70 is stopped, the umbrella portion 42 of the valve member 40 contacts the stopper 50 and is separated from the valve seat 34. is doing. At this time, the end surface 45 of the shaft portion 41 of the valve member 40 protrudes substantially to the same position as the end surface 36 on the second guide portion 76 side of the first guide portion 35 or slightly toward the second guide portion 76 side from the end surface 36. In the position. On the other hand, when the needle 60 is attracted toward the counter valve member 40 by energizing the coil 71 of the electromagnetic drive unit 70, the umbrella portion 42 of the valve member 40 is seated on the valve seat 34 of the valve body 30. At this time, the end surface 45 of the valve member 40 is in a position protruding slightly toward the second guide portion 76 side from the end surface 36 of the first guide portion 35.

  Thus, when the umbrella portion of the valve member 40 reciprocates between the stopper 50 and the valve seat 34, the end surface 45 of the valve member 40 is positioned in the vicinity of the end surface 36 of the first guide portion 35. Thereby, when the needle 60 contacts the shaft portion 41 and presses the valve member 40 in the valve opening direction, the needle 60 presses the shaft portion 41 in the vicinity of the end face 36. Therefore, at this time, even if a radial force acts on the end surface 45 side end portion of the shaft portion 41, the outer peripheral wall of the shaft portion 41 is pressed against the inner peripheral wall of the first guide portion 35 that forms the first insertion hole 351. The power that can be achieved is small. As a result, the stress generated in the vicinity of the end face 36 of the shaft portion 41 can be reduced. Therefore, breakage or damage of the shaft portion 41 can be reduced.

  In the first embodiment described above, the valve body 30 includes the first guide portion 35 having the first insertion hole 351 that slidably guides the shaft portion 41 of the valve member 40. Therefore, when the electromagnetic drive unit 70 moves the valve member 40 in the valve opening direction or the valve closing direction via the needle 60, the valve member 40 is guided to reciprocate in the axial direction by the first guide unit 35. . Thereby, the valve member 40 can be stably seated or separated from the valve seat 34 without moving in the radial direction. Therefore, the flow rate of the fuel supplied to the pressurizing chamber 113 and the flow rate of the fuel discharged from the high-pressure pump 10 can be stabilized.

  Moreover, in 1st Embodiment, the electromagnetic drive part 70 is provided with the 2nd guide part 76 which has the 2nd penetration hole 761 which guides the needle 60 so that sliding is possible. Therefore, when the valve member 40 is moved in the valve opening direction or the valve closing direction via the needle 60 by the electromagnetic drive unit 70, the needle 60 is guided to reciprocate in the axial direction by the second guide unit 76. Thereby, the needle 60 can be stably brought into contact with the valve member 40 without moving in the radial direction. As a result, the reciprocating movement of the valve member 40 in contact with the needle 60 is stabilized, and the valve member 40 can be seated or separated from the valve seat 34 more stably.

(Second Embodiment)
The principal part of the high-pressure pump according to the second embodiment of the present invention is shown in FIG. In the second embodiment, the shaft portion of the valve member and the needle have different outer diameters. Moreover, in 2nd Embodiment, the axial direction position of the contact location of a shaft part and a needle differs from 1st Embodiment.

  In the second embodiment, the outer diameter of the end portion on the shaft portion 41 side of the needle 60 is smaller than the outer diameter of the end portion on the needle 60 side of the shaft portion 41. That is, the shaft portion 41 and the needle 60 have different outer diameters at the end portions in contact with each other. When the needle 60 abuts on the shaft portion 41, the shaft portion 41 and the needle 60 abut on the end surface 45 and the end surface 63. At this time, the contact area between the shaft portion 41 and the needle 60 is the same as the area of the end surface 63 of the needle 60. That is, the contact area between the shaft portion 41 and the needle 60 can be the area of the end surface of the shaft portion 41 and the needle 60 whose outer diameter is smaller. As a result, when the needle 60 abuts against the shaft portion 41, the contact area between the shaft portion 41 and the needle 60 can be made substantially constant even if the shaft 41 and the shaft of the needle 60 are out of alignment. it can. As a result, the force applied by the needle 60 to the shaft portion 41 is stabilized, and the reciprocating movement of the valve member 40 can be further stabilized.

  FIG. 3 shows a state in which the valve member 40 is separated from the valve seat 34 and is in contact with the stopper 50. At this time, the end surface 45 of the shaft portion 41 that is in contact with the needle 60 is located closer to the second guide portion 76 than the end surface 36 of the first guide portion 35. On the other hand, in a state where the valve member 40 is seated on the valve seat 34, the end surface 45 of the shaft portion 41 is located slightly closer to the second guide portion 76 than the position of the end surface 45 in FIG. That is, in the second embodiment, the shaft portion 41 and the needle 60 are always in contact with each other between the end surface 36 of the first guide portion 35 and the end surface 77 of the second guide portion 76 on the first guide portion 35 side. It is provided so as to be located between them. Thus, when the shaft portion 41 and the needle 60 reciprocate, the respective contact side end portions are within the moving range up to the end surface 77 or the end surface 36. Therefore, even when the shaft member 41 and the needle 60 are assembled in a non-coaxial state, the valve member 40 and the needle 60 are in contact with the end surface 77 or the end surface 36 when reciprocating. Never do. As a result, the movement of the shaft portion 41 and the needle 60 is not hindered by the end surface 77 and the end surface 36. Therefore, regardless of the assembled state of the valve member 40 and the needle 60, the needle 60 can be properly brought into contact with the shaft portion 41. Therefore, when assembling the valve member 40 and the needle 60, high accuracy such as accurate coaxial assembly is not required, and the assembly can be facilitated.

(Third embodiment)
The principal part of the high pressure pump by 3rd Embodiment of this invention is shown in FIG. In the third embodiment, as in the second embodiment, the shaft portion of the valve member and the needle have different outer diameters. Moreover, in 3rd Embodiment, the axial direction position of the contact location of a axial part and a needle differs from 1st Embodiment and 2nd Embodiment.

  In the third embodiment, similarly to the second embodiment, the outer diameter of the end portion on the side of the shaft portion 41 of the needle 60 is formed smaller than the outer diameter of the end portion on the side of the needle 60 of the shaft portion 41 of the valve member 40. . That is, the shaft portion 41 and the needle 60 have different outer diameters at the end portions in contact with each other. Accordingly, the diameters of the first insertion hole 351 through which the shaft portion 41 is slidably inserted and the second insertion hole 761 through which the needle 60 is slidably inserted are also different.

  FIG. 4 shows a state where the valve member 40 is separated from the valve seat 34 and is in contact with the stopper 50. At this time, the end surface 45 of the shaft portion 41 in contact with the needle 60 is located on the side opposite to the second guide portion 76 than the end surface 36 of the first guide portion 35. On the other hand, in a state where the valve member 40 is seated on the valve seat 34, the end surface 45 of the shaft portion 41 is located slightly closer to the second guide portion 76 than the position of the end surface 45 in FIG. It is located on the second guide portion 76 side.

  As described above, in the third embodiment, the needle 60 is “when the reciprocating movement is performed, the end on the end surface 63 side enters the first insertion hole 351 beyond the end surface 36 of the first guide portion 35”. It becomes a state. In addition, even if “the shaft portion 41 and the needle 60 are assembled in a non-coaxial state”, the end portion on the end surface 63 side of the needle 60 has the end surface 36 or the first insertion hole 351 formed therein. The one guide portion 35 can reciprocate without contacting the inner peripheral wall. This is a configuration that is made possible by the diameter of the first insertion hole 351 being larger than the outer diameter of the end of the needle 60 on the end face 63 side.

  As described above, in the third embodiment, when the valve member 40 and the needle 60 are assembled, high accuracy such as accurate coaxial assembly is not required, and the assembly can be facilitated. Moreover, according to the said structure, the freedom degree of design can be raised regarding the axial direction length of the axial part 41 and the needle 60, and the axial direction position of the contact location of the axial part 41 and the needle 60. FIG.

(Fourth embodiment)
The principal part of the high-pressure pump according to the fourth embodiment of the present invention is shown in FIG. In the fourth embodiment, the shaft portion of the valve member and the needle have different outer diameters. Moreover, in 4th Embodiment, the axial direction position of the contact location of a shaft part and a needle differs from 1st-3rd embodiment.

  In the fourth embodiment, the outer diameter of the end portion on the needle 60 side of the shaft portion 41 of the valve member 40 is smaller than the outer diameter of the end portion on the shaft portion 41 side of the needle 60. That is, the shaft portion 41 and the needle 60 have different outer diameters at the end portions in contact with each other. Accordingly, the diameters of the first insertion hole 351 through which the shaft portion 41 is slidably inserted and the second insertion hole 761 through which the needle 60 is slidably inserted are also different.

  FIG. 5 shows a state in which the valve member 40 is separated from the valve seat 34 and is in contact with the stopper 50. At this time, the end surface 45 of the shaft portion 41 that is in contact with the needle 60 is located on the side opposite to the first guide portion 35 than the end surface 77 of the second guide portion 76. On the other hand, in a state in which the valve member 40 is seated on the valve seat 34, the end surface 45 of the shaft portion 41 is located slightly on the side opposite to the first guide portion 35 than the position of the end surface 45 in FIG. It is located on the side opposite to the first guide portion 35.

  As described above, in the fourth embodiment, the shaft portion 41 indicates that “when reciprocating, the end portion on the end surface 45 side passes through the end surface 77 of the second guide portion 76 and enters the second insertion hole 761. State. Further, even if “the shaft portion 41 and the needle 60 are assembled in a non-coaxial state”, the end portion on the end surface 45 side of the shaft portion 41 is formed with the end surface 77 or the second insertion hole 761. It can reciprocate without contacting the inner peripheral wall of the second guide portion 76. This is a configuration that is made possible by the fact that the diameter of the second insertion hole 761 is larger than the outer diameter of the end portion on the end face 45 side of the shaft portion 41.

  As described above, in the fourth embodiment, when the valve member 40 and the needle 60 are assembled, high accuracy such as accurate coaxial assembly is not required, and the assembly can be facilitated. Further, according to the above configuration, as in the third embodiment, the degree of freedom in design with respect to the axial lengths of the shaft portion 41 and the needle 60 and the axial position of the contact portion between the shaft portion 41 and the needle 60. Can be increased.

(Fifth embodiment)
The principal part of the high-pressure pump according to the fifth embodiment of the present invention is shown in FIG. In 5th Embodiment, the shape of the valve member side edge part of a needle differs from the above-mentioned embodiment.
In 5th Embodiment, the axial part 41 side edge part of the needle 60 is formed in the taper shape in which an outer diameter becomes small as it goes to the axial part 41 side. That is, the outer diameter of the end surface 63 on the shaft portion 41 side of the needle 60 is smaller than the outer diameter of the portion other than the end portion on the shaft portion 41 side of the needle 60. The outer diameter of the portion of the needle 60 other than the end on the shaft 41 side and the outer diameter of the shaft 41 are substantially the same.

  When the needle 60 abuts on the shaft portion 41, the shaft portion 41 and the needle 60 abut on the end surface 45 and the end surface 63. At this time, the contact area between the shaft portion 41 and the needle 60 is the same as the area of the end surface 63 of the needle 60. That is, the contact area between the shaft portion 41 and the needle 60 can be the area of the end face 63 of the needle 60, that is, the end face of the end face 45 and the end face 63 having the smaller area. As a result, when the needle 60 abuts against the shaft portion 41, the contact area between the shaft portion 41 and the needle 60 can be made substantially constant even if the shaft 41 and the shaft of the needle 60 are out of alignment. it can. As a result, the force applied by the needle 60 to the shaft portion 41 is stabilized, and the reciprocating movement of the valve member 40 can be stabilized.

(Sixth embodiment)
The principal part of the high-pressure pump according to the sixth embodiment of the present invention is shown in FIG. In 6th Embodiment, the shape of the valve member side edge part of a needle differs from the above-mentioned embodiment.
In the sixth embodiment, the end surface 63 on the shaft portion 41 side of the needle 60 is formed in a spherical shape. Therefore, when the end surface 63 of the needle 60 abuts on the end surface 45 of the shaft portion 41, the contact area between the shaft portion 41 and the needle 60 is extremely small. Thereby, even if it is in the state where the axis | shaft of the shaft part 41 and the needle 60 shifted | deviated at this time, the contact area of the shaft part 41 and the needle 60 can be made substantially constant. As a result, the force applied by the needle 60 to the shaft portion 41 is stabilized, and the reciprocating movement of the valve member 40 can be further stabilized.

(Other embodiments)
In the second embodiment described above, an example in which the outer diameter of the end portion on the shaft side of the needle is smaller than the outer diameter of the end portion on the needle side of the shaft portion has been described. On the other hand, in another embodiment of the present invention, the outer diameter of the needle side end of the shaft is smaller than the outer diameter of the needle side end of the needle, or the outer diameter of the needle side end of the needle. It may be formed in the same size as. In another embodiment of the present invention, the axial position of the contact portion between the needle and the shaft portion may be any position in the axial direction as long as it is between the first guide portion and the second guide portion. Also good.

  In the above-described fifth embodiment, the example in which the shaft side end of the needle is formed in a tapered shape whose outer diameter decreases toward the shaft side is shown. On the other hand, in another embodiment of the present invention, the needle side end of the shaft portion may be formed in a tapered shape whose outer diameter decreases toward the needle side. Even if the needle side end portion of the shaft portion is formed in this way, the same effects as in the fifth embodiment can be obtained.

  In the above-described sixth embodiment, an example in which the end surface on the shaft portion side of the needle is formed in a spherical shape has been described. On the other hand, in another embodiment of the present invention, the end surface on the needle side of the shaft portion may be formed in a spherical shape. Even if the end surface on the needle side of the shaft portion is formed in this way, the same effects as in the sixth embodiment can be obtained.

In the above-described embodiments, the valve member is opened when the coil portion of the electromagnetic drive portion is not energized, and the normally open valve structure is shown in which the valve member is closed when the coil portion is energized. It was. On the other hand, in another embodiment of the present invention, a normally closed valve structure in which the valve member opens when the coil portion is energized may be used.
Thus, the present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the scope of the invention.

The fragmentary sectional view of the high-pressure pump by a 1st embodiment of the present invention. 1 is a cross-sectional view of a high pressure pump according to a first embodiment of the present invention. Sectional drawing of the principal part of the high pressure pump by 2nd Embodiment of this invention. Sectional drawing of the principal part of the high pressure pump by 3rd Embodiment of this invention. Sectional drawing of the principal part of the high pressure pump by 4th Embodiment of this invention. Sectional drawing of the principal part of the high pressure pump by 5th Embodiment of this invention. Sectional drawing of the principal part of the high pressure pump by 6th Embodiment of this invention.

Explanation of symbols

  10: high pressure pump, 11: housing body (housing), 12: cover (housing), 13: plunger, 21: spring (first urging member), 22: spring (second urging member), 30: valve body , 34: valve seat, 40: valve member, 41: shaft part (valve member), 42: umbrella part (valve member), 50: stopper, 60: needle, 70: electromagnetic drive part, 71: coil (coil part) 72: fixed core (coil part), 73: movable core (coil part), 75: flange (coil part), 78: spool (coil part), 79: cylindrical member (coil part), 100: fuel passage, 113 : Pressurization chamber

Claims (7)

A reciprocating plunger; and
A pressure chamber in which fuel is pressurized by the plunger, and a housing having a fuel passage for guiding the fuel to the pressure chamber;
A valve body provided in the fuel passage and having a valve seat on a side wall surface of the pressurizing chamber;
A shaft portion, and an umbrella portion connected to the end portion on the pressurizing chamber side of the shaft portion, and fuel that circulates in the fuel passage when the umbrella portion is seated on or separated from the valve seat A valve member that interrupts the flow of
A stopper provided on the pressurizing chamber side of the valve member and restricting movement of the valve member in a valve opening direction;
A first biasing member that is provided between the stopper and the valve member and biases the valve member in a valve closing direction;
One end of the shaft portion can be brought into contact with the end portion of the shaft portion opposite to the umbrella portion, and a needle provided to be movable in the same direction as the valve member when the valve member is opened or closed; and
A second biasing member that biases the needle in the valve opening direction of the valve member;
An electromagnetic drive unit having a coil part capable of attracting the needle in either the valve closing direction or the valve opening direction of the valve member;
The said valve body is provided with the 1st guide part which has the 1st insertion hole which guides the said axial part so that sliding is possible, The high pressure pump characterized by the above-mentioned.   2. The high-pressure pump according to claim 1, wherein the electromagnetic driving unit includes a second guide unit having a second insertion hole that slidably guides the needle. 3.   The shaft portion and the needle are always positioned between the end portion on the second guide portion side of the first guide portion and the end portion on the first guide portion side of the second guide portion. The high-pressure pump according to claim 2, wherein the high-pressure pump is provided.   4. The high-pressure pump according to claim 2, wherein the shaft portion and the needle have different outer diameters at the end portions in contact with each other.   The high-pressure pump according to any one of claims 1 to 4, wherein the needle side end portion of the shaft portion is formed in a tapered shape having an outer diameter that decreases toward the needle side.   5. The high-pressure pump according to claim 1, wherein an end portion of the needle side of the needle is formed in a tapered shape whose outer diameter decreases toward the shaft side. .   5. The high pressure according to claim 1, wherein one of the needle side end portion of the shaft portion and the shaft portion side end surface of the needle is formed in a spherical shape. pump.

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