JP5126602B2 - High pressure pump - Google Patents

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 causes the valve member to reciprocate in a direction to be seated on or away from the valve seat formed on the valve body via the needle. Moreover, the stopper provided in the pressurizing chamber side of the valve member restricts the movement of the valve member in the pressurizing chamber side, that is, in the valve opening direction.

  By the way, in the high pressure pump of Patent Document 1, the fuel passage is formed between the valve member and the valve seat on the first passage formed between the needle and the valve body, and on the pressure chamber side of the first passage. And a third passage formed in the stopper on the pressure chamber side of the second passage. In the high pressure pump, when the fuel is sucked into the pressurizing chamber, the fuel flows in the order of the first passage, the second passage, and the third passage and is sucked into the pressurizing chamber. On the other hand, when metering the fuel supplied to the pressurizing chamber, the fuel flows from the pressurizing chamber in the order of the third passage, the second passage, and the first passage. The valve member controls the flow rate of the fuel flowing through the fuel passage by being seated on the valve seat or separated from the valve seat. That is, the cross-sectional area of the second passage formed between the valve member and the valve seat can be an important design item in controlling the flow rate of the fuel flowing through the fuel passage.

In patent document 1, it is not prescribed | regulated regarding the relationship of the cross-sectional area of each said 1st-3rd channel | path. Therefore, when the cross-sectional area of each of the first passage and the third passage is smaller than the cross-sectional area of the second passage located between the first passage and the third passage, Pressure loss due to throttling may occur in the passage or the third passage. The pressure loss generated in the first passage or the third passage affects the control of the fuel flow rate in the second passage. As a result, the flow rate of the fuel flowing through the fuel passage at the time of inhalation or metering may not be stable, and the fuel discharge amount and pressure from the high pressure pump may become unstable.
JP-T-2002-521616

  An object of the present invention is to provide a high-pressure pump in which the flow rate at the time of intake and metering of fuel supplied to a pressurizing chamber is stable and the amount and pressure of fuel to be discharged can be controlled with high accuracy.

  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 for guiding the fuel to the pressurizing chamber, and a pressurizing chamber are provided in the fuel passage. A valve body having a valve seat on the chamber side wall surface, a valve member that interrupts the flow of fuel flowing through the fuel passage by being seated on or separated from the valve seat, and a pressurizing chamber side of the valve member A stopper that restricts the movement of the valve member in the valve opening direction when the valve member abuts, and a first biasing member that is provided between the stopper and the valve member and biases the valve member in the valve closing direction. , One end of the valve member can be brought into contact with the end of the valve member opposite to the stopper, and the needle can be moved in the same direction as the valve member when the valve member is opened or closed; A second urging member for urging the valve in the valve opening direction, and the needle as a valve member It comprises an electromagnetic drive unit, a having a coil portion capable attracted to either the valve closing direction or opening direction.

The fuel passage is a first passage formed on the side of the valve body opposite to the pressurizing chamber, and a second passage formed annularly between the valve member and the valve seat when the valve member is separated from the valve seat. And a third passage formed in the stopper. If the minimum cross-sectional area of the first passage is S1, the minimum cross-sectional area of the second passage when the valve member is in contact with the stopper is S2, and the minimum cross-sectional area of the third passage is S3, the first passage, The two passages and the third passage are formed so as to satisfy the relationships of S1> S2 and S3> S2. That is, the minimum cross-sectional area of the first passage and the minimum cross-sectional area of the third passage are both larger than the minimum cross-sectional area of the second passage. Therefore, it is possible to reduce pressure loss due to the throttle that may occur in the first passage and the third passage on the upstream side or the downstream side of the second passage at the time of inhaling or metering fuel into the pressurizing chamber. Thereby, the fuel flowing through the fuel passage is less affected by the first passage or the third passage, and the flow rate is controlled by the second passage having a variable minimum cross-sectional area. As a result, the flow rate at the time of intake and metering of the fuel supplied to the pressurizing chamber can be stabilized. Therefore, the amount and pressure of fuel discharged from the high-pressure pump can be controlled with high accuracy.
In the first aspect of the invention, the third passage is connected to the large-diameter passage and the non-pressurizing chamber side of the large-diameter passage having a smaller diameter than the large-diameter passage and has a step between the large-diameter passage. It consists of a small diameter passage to be formed. In the present invention, the first passage, the second passage, and the third passage satisfy the relationship regarding the minimum cross-sectional area. Therefore, even if the third passage is formed in a shape composed of a large diameter passage and a small diameter passage as described above, the above effect can be obtained.
In the invention according to claim 2, the third passage is formed in a tapered shape having a diameter that decreases from the pressurizing chamber side to the counter pressurizing chamber side. In the present invention, the first passage, the second passage, and the third passage satisfy the relationship regarding the minimum cross-sectional area in the first aspect of the invention. Therefore, even if the third passage is formed in a tapered shape as described above, the same effect as that of the first aspect of the invention can be obtained. Further, by making the shape of the third passage tapered, the flow coefficient of the third passage can be increased as compared with the case where the passage has a linear shape or a shape having a step. Thereby, the pressure loss in the third passage can be further reduced.

In the invention according to claim 3 , the first passage, the second passage, and the third passage are formed so as to satisfy the relationship of S1>S3> S2. That is, when the fuel is sucked into the pressurizing chamber, the first passage located at the most upstream of the three passages is formed so that the minimum cross-sectional area is larger than the minimum cross-sectional area of the other two passages. . Thereby, since the flow volume of the fuel which distribute | circulates a 1st channel | path can be ensured, the suction | inhalation efficiency of the fuel to a pressurization chamber can be improved. In addition, when the fuel supplied to the pressurizing chamber is metered, the third passage located upstream of the three passages is formed so that the minimum cross-sectional area is smaller than the minimum cross-sectional area of the first passage. . In addition, the flow rate of the fuel flowing through the third passage increases due to the throttling effect when flowing into the third passage from the pressurizing chamber. Thereby, the fuel flow velocity can be increased on the downstream side of the third passage, that is, on the second passage side. Therefore, the fuel flow to the second passage is stabilized. As a result, the fuel can smoothly flow into the second passage. As described above, in the present invention, the fuel supplied to the pressurizing chamber can achieve both high suction efficiency and stable metering characteristics.

In the invention according to claim 4, at least one of the first passage and the third passage is formed in plural, S1 is the sum of the minimum cross-sectional areas of the first passage, and S3 is the sum of the minimum cross-sectional areas of the third passage. is there. In the present invention, first passage, second passage and third passage, satisfy the relationship of the minimum cross-sectional area of at inventions of the preceding claims 1-3, wherein. Therefore, even if the first passage or the third passage has formed therein a plurality, it is possible to obtain the same effect as inventions of the claims 1-3, wherein.

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 described above, since the second passage 122 is a passage formed between the valve member 40 and the valve seat 34, the shape and size of the flow path change when the valve member 40 reciprocates. When the valve member 40 is seated on the valve seat 34, the size of the flow path of the second passage 122 is minimum, that is, zero. On the other hand, when the valve member 40 is separated from the valve seat 34 and comes into contact with the stopper 50, the size of the flow path of the second passage 122 is maximized.

  Next, the relationship regarding the cross-sectional areas of the first passage 121, the second passage 122, and the third passage 123 will be described. The phrase “minimum cross-sectional area” used below refers to a cross-sectional area at a portion of the passage where the flow path is the narrowest. As shown in FIG. 1, the sum of the minimum cross-sectional areas of the first passage 121 is S1, the minimum cross-sectional area of the second passage 122 when the valve member 40 is in contact with the stopper 50 is S2, and the minimum of the third passage 123 is Assuming that the total cross-sectional area is S3, the first passage 121, the second passage 122, and the third passage 123 are formed so as to satisfy the relationship of S1> S3> S2. That is, from the relational expression, “1” “the sum of the minimum cross-sectional areas of the first passage 121 (S 1) and the sum of the minimum cross-sectional areas of the third passage 123 (S 3) are both the minimum cut-off of the second passage 122. "Area greater than area (S2)", "2" "the sum (S1) of the minimum cross-sectional area of the first passage 121 is smaller than the minimum cross-sectional area (S2) or the sum of the minimum cross-sectional areas (S3) of the other passages" It is understood that “large”, “3” “the sum of the minimum cross-sectional areas of the third passages 123 (S3) is smaller than the sum of the minimum cross-sectional areas of the first passages 121 (S1)”.

  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 fuel pressure in the pressurizing chamber 113 rises, 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 greater 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.

  As described above, in the first embodiment, the first passage 121, the second passage 122, and the third passage 123 are formed so as to satisfy the relationship of S1> S3> S2. In other words, “1” “the sum of the minimum cross-sectional areas of the first passage 121 (S1) and the sum of the minimum cross-sectional areas of the third passage 123 (S3) are both from the minimum cross-sectional area of the second passage 122 (S2). "2" "the sum of the minimum cross-sectional areas (S1) of the first passage 121 is greater than the minimum cross-sectional area (S2) or the sum of the minimum cross-sectional areas (S3) of the other passages", "3" “The sum (S3) of the minimum cross-sectional area of the third passage 123 is smaller than the sum (S1) of the minimum cross-sectional area of the first passage 121”.

  “1” “A sum of the minimum cross-sectional areas of the first passage 121 (S1) and a sum of the minimum cross-sectional areas of the third passage 123 (S3) are both larger than the minimum cross-sectional area of the second passage 122 (S2). Therefore, the pressure loss due to the throttle that may occur in the first passage 121 and the third passage 123 on the upstream side or the downstream side of the second passage 122 during the intake or metering of the fuel into the pressurizing chamber 113 is reduced. be able to. As a result, the fuel flowing through the fuel passage 100 is less affected by the first passage 121 or the third passage 123, and the flow rate is controlled by the second passage 122 whose minimum cross-sectional area is variable. As a result, the flow rate at the time of intake and metering of the fuel supplied to the pressurizing chamber 113 can be stabilized. Therefore, the amount and pressure of fuel discharged from the high-pressure pump 10 can be controlled with high accuracy.

  Further, “2” “the sum of the minimum cross-sectional areas (S1) of the first passage 121 is larger than the minimum cross-sectional area (S2) or the sum of the minimum cross-sectional areas (S3) of the other passages”. When the fuel is sucked into the fuel, it is possible to secure the flow rate of the fuel flowing through the first passage 121 located at the most upstream among the three passages (first to third passages). Thereby, the fuel suction efficiency into the pressurizing chamber 113 can be increased.

  Further, “3” “the sum of the minimum cross-sectional areas of the third passage 123 (S3) is smaller than the sum of the minimum cross-sectional areas of the first passage 121 (S1)” and “the fuel supplied to the pressurizing chamber 113 During the metering, the flow rate of the fuel flowing through the third passage 123 increases due to the throttling effect when it flows into the third passage 123 from the pressurizing chamber 113 ”. ), The fuel flow rate can be increased on the downstream side of the third passage 123 located on the most upstream side, that is, on the second passage 122 side. Therefore, the fuel flow to the second passage 122 is stabilized. As a result, the fuel can smoothly flow into the second passage 122. Thus, in this embodiment, regarding the fuel supplied to the pressurizing chamber 113, both high suction efficiency and stable metering characteristics can be achieved.

(Second Embodiment)
A part of the high-pressure pump according to the second embodiment of the present invention is shown in FIG. In the second embodiment, the shape of the third passage formed in the stopper is different from that in the first embodiment.
In the second embodiment, the third passage 123 includes a large-diameter passage 201 and a small-diameter passage 202 that is connected to the large-diameter passage 201 on the side opposite to the pressure chamber 113. The small diameter passage 202 has a smaller diameter than the large diameter passage 201. Therefore, a step 203 is formed between the small diameter passage 202 and the large diameter passage 201. In the second embodiment, the sum of the cross-sectional areas of the small-diameter passages 202 is the sum of the minimum cross-sectional areas of the third passages 123 (S3).

  Also in the second embodiment, similarly to the first embodiment, the first passage 121, the second passage 122, and the third passage 123 are formed so as to satisfy the relationship of S1> S3> S2. Therefore, in the second embodiment, even if the third passage 123 is formed in a shape including the large-diameter passage 201 and the small-diameter passage 202, the same effect as in the first embodiment described above can be obtained.

(Third embodiment)
A part of the high-pressure pump according to the third embodiment of the present invention is shown in FIG. In 3rd Embodiment, the shape of the 3rd channel | path formed in a stopper differs from the case of 1st Embodiment and 2nd Embodiment.
In 3rd Embodiment, the 3rd channel | path 123 is formed in the taper shape in which a diameter becomes small as it goes to the non-pressurization chamber 113 side from the pressurization chamber 113 side. In the third embodiment, the sum of the cross-sectional areas of the end portion of the third passage 123 on the side opposite to the pressurizing chamber 113 is the sum of the minimum cross-sectional areas of the third passage 123 (S3).

  Also in the third embodiment, similarly to the first embodiment and the second embodiment, the first passage 121, the second passage 122, and the third passage 123 are formed so as to satisfy the relationship of S1> S3> S2. . Therefore, in 3rd Embodiment, even if the 3rd channel | path 123 is formed in the taper shape, the effect similar to the above-mentioned 1st Embodiment or 2nd Embodiment can be acquired.

  In the third embodiment, the shape of the third passage 123 is tapered, so that the passage has a linear shape (for example, the shape of the third passage of the first embodiment) or a shape having a step (for example, the second shape). Compared to the case of the shape of the third passage of the embodiment), the flow coefficient of the third passage 123 can be increased. Thereby, the pressure loss in the 3rd channel | path 123 can be reduced more.

(Other embodiments)
In another embodiment of the present invention, the first passage, the second passage, and the third passage do not satisfy the relationship “S1>S3> S2”, but even “the relationship S1> S2 and S3> S2”. It only has to satisfy. In other words, the minimum cross-sectional area (total) of the first passage and the minimum cross-sectional area (total) of the third passage are only required to be larger than the minimum cross-sectional area of the second passage. By forming the first passage, the second passage, and the third passage in this way, pressure loss due to the throttle that may occur in the first passage and the third passage during intake or metering of fuel into the pressurizing chamber is reduced. can do.

  In another embodiment of the present invention, the first passage, the second passage, and the third passage satisfy “a relationship of S1> S3> S2” or “a relationship of S1> S2 and S3> S2”. If it is, it may be formed in any shape. In addition, each of the first passage and the third passage may not be plural but one.

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. The fragmentary sectional view of the high-pressure pump by a 2nd embodiment of the present invention. The fragmentary sectional view of the high-pressure pump by a 3rd embodiment of the present 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, 50: stopper, 60: needle, 70: electromagnetic drive unit, 71: coil (coil unit), 72: fixed core (coil unit), 73: movable core (coil unit) 75: flange (coil part), 78: spool (coil part), 79: cylindrical member (coil part), 100: fuel passage, 113: pressurizing chamber, 121: first passage (fuel passage), 122: first 2 passages (fuel passage), 123: 3rd passage (fuel passage)

Claims (4)

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 valve member that interrupts the flow of fuel flowing through the fuel passage by being seated on or separated from the valve seat;
A stopper that is provided on the pressurizing chamber side of the valve member and restricts movement of the valve member in a valve opening direction when the valve member abuts;
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 valve member can be brought into contact with the end opposite to the stopper side of the valve member, and a needle provided to be movable in the same direction as the valve member when the valve member is opened or closed;
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 fuel passage is a first passage formed on the valve body on the side opposite to the pressurizing chamber of the valve body, and is annular between the valve member and the valve seat when the valve member is separated from the valve seat. A second passage formed in the second passage and a third passage formed in the stopper,
S1 is the minimum sectional area of the first passage, S2 is the minimum sectional area of the second passage when the valve member is in contact with the stopper, and S3 is the minimum sectional area of the third passage.
The first passage, the second passage, and the third passage are formed so as to satisfy a relationship of S1> S2 and S3> S2 ,
The third passage includes a large-diameter passage and a small-diameter passage having a diameter smaller than that of the large-diameter passage and connected to the non-pressurizing chamber side of the large-diameter passage to form a step between the large-diameter passage. A high-pressure pump characterized by that. 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 valve member that interrupts the flow of fuel flowing through the fuel passage by being seated on or separated from the valve seat;
A stopper that is provided on the pressurizing chamber side of the valve member and restricts movement of the valve member in a valve opening direction when the valve member abuts;
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 valve member can be brought into contact with the end opposite to the stopper side of the valve member, and a needle provided to be movable in the same direction as the valve member when the valve member is opened or closed;
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 fuel passage is a first passage formed on the valve body on the side opposite to the pressurizing chamber of the valve body, and is annular between the valve member and the valve seat when the valve member is separated from the valve seat. A second passage formed in the second passage and a third passage formed in the stopper,
S1 is the minimum sectional area of the first passage, S2 is the minimum sectional area of the second passage when the valve member is in contact with the stopper, and S3 is the minimum sectional area of the third passage.
The first passage, the second passage, and the third passage are formed so as to satisfy a relationship of S1> S2 and S3> S2 ,
The high-pressure pump according to claim 3, wherein the third passage is formed in a tapered shape having a diameter that decreases from the pressurizing chamber side toward the non-pressurizing chamber side . The high-pressure pump according to claim 1 or 2 , wherein the first passage, the second passage, and the third passage are formed so as to satisfy a relationship of S1>S3> S2. At least one of the first passage and the third passage is formed in plural,
S1 is the sum of the minimum cross-sectional areas of the first passage,
4. The high-pressure pump according to claim 1, wherein S <b> 3 is a sum of minimum sectional areas of the third passages.

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