JP5071525B2 - High pressure pump - Google Patents

Description

  The present invention relates to a high-pressure pump that pressurizes and discharges fuel sucked from a suction chamber into a pressurization chamber by reciprocating movement of a plunger.

  A high-pressure pump is known in which fuel introduced into a suction chamber from a fuel inlet by a low-pressure pump or the like is sucked into a pressurization chamber from a suction chamber by a reciprocating movement of the plunger, and is pressurized and discharged (for example, Patent Document 1). 2).

JP 2002-54531 A JP 2003-35239 A

  However, if the amount of fuel sucked into the pressurizing chamber from the suction chamber increases during the suction stroke in which the plunger descends, the pressure in the suction chamber may decrease. In particular, when the plunger diameter or the amount of reciprocation of the plunger increases due to a request to increase the discharge amount of the high-pressure pump, the amount of fuel sucked into the pressurizing chamber from the suction chamber increases, and the pressure in the suction chamber tends to decrease. Further, when the rotation speed of the high pressure pump increases and the reciprocating speed of the plunger increases, the amount of fuel sucked into the pressurizing chamber from the suction chamber exceeds the amount of fuel introduced from the low pressure pump into the suction chamber due to the lowering of the plunger. As a result, the pressure in the suction chamber tends to decrease.

  Thus, when the pressure in the suction chamber decreases during the suction stroke in which the plunger descends, there is a problem that fuel is not sufficiently sucked from the suction chamber into the pressurizing chamber, resulting in a shortage of discharge amount.

  Further, when the fuel is returned from the pressurizing chamber to the suction chamber while the plunger is raised, the pressure in the suction chamber increases. When the plunger repeatedly descends and rises, the pressure in the suction chamber varies and pressure pulsation occurs in the suction chamber. As described above, when the required discharge amount increases or the rotation speed of the high pressure pump increases, the pressure pulsation generated in the suction chamber further increases. Thus, when pressure pulsation occurs on the suction chamber side, there is a problem that fuel cannot be sufficiently sucked from the suction chamber into the pressurizing chamber, resulting in a shortage of discharge amount.

  The present invention has been made to solve the above problems, and it is an object of the present invention to provide a high-pressure pump that sucks a required amount of fuel from a suction chamber into a pressurization chamber.

  According to the first aspect of the present invention, when the plunger is lowered and fuel is sucked from the suction chamber into the pressurizing chamber, the fuel is introduced not only from the fuel inlet but also from the fuel chamber into the suction chamber. The pressure drop in the suction chamber can be reduced. Thereby, a required amount of fuel can be sucked into the pressurizing chamber from the suction chamber.

  On the other hand, when the plunger is raised and the fuel is returned from the pressurizing chamber to the suction chamber, the fuel is discharged from the suction chamber not only to the fuel inlet side but also to the discharge passage. Is reduced. At this time, since the volume of the fuel chamber increases, a part of the fuel returned to the suction chamber passes through the discharge passage and is efficiently discharged into the fuel chamber. As a result, the pressure pulsation in the suction chamber that occurs when the plunger repeatedly rises and falls can be reduced, so that a necessary amount of fuel can be sucked into the pressurization chamber from the suction chamber.

  According to a second aspect of the present invention, the metering valve includes a first spring that biases the valve member in a direction in which the valve member is seated on the valve seat, and a shaft in a direction in which the valve member is separated from the valve seat. You may make it the structure which has a 2nd spring urged | biased with a bigger force than the urging | biasing force of a 1st spring.

  According to a third aspect of the present invention, the valve member is disposed in the pressurizing chamber, the shaft passes through the suction chamber, and the coil is disposed on the opposite side of the pressurizing chamber across the suction chamber. It may be.

  According to a fourth aspect of the present invention, the valve member is disposed in the pressurizing chamber, a communication hole that communicates the suction chamber and the pressurization chamber is formed on the inner peripheral side of the valve seat, and the shaft passes through the communication hole. The valve member may be separated from the valve seat by contacting the valve member from the suction chamber side.

  According to a fifth aspect of the present invention, the shaft may be configured such that the end abuts against the bottom wall of the cup-shaped valve member from the valve seat side.

  According to a sixth aspect of the present invention, the metering valve has a stopper disposed in the pressurizing chamber together with the valve member, and the spring is interposed between the valve member and the stopper in the pressurizing chamber. May be.

(A) is sectional drawing which shows the high pressure pump by 1st Embodiment of this invention, (B) is the figure which looked at the stopper of the metering valve from the plunger side. It is sectional drawing which shows the high pressure pump by 1st Embodiment at the time of a suction stroke. It is sectional drawing which shows the high pressure pump by 2nd Embodiment of this invention. It is sectional drawing which shows the high pressure pump by 3rd Embodiment of this invention. It is sectional drawing which shows the high pressure pump by 4th Embodiment of this invention. It is sectional drawing which shows the high pressure pump by 5th Embodiment of this invention. It is sectional drawing which shows the high pressure pump by 6th Embodiment of this invention. It is sectional drawing which shows the high pressure pump by 7th Embodiment of this invention. It is sectional drawing which shows the high pressure pump by 8th Embodiment of this invention. It is sectional drawing which shows the high pressure pump by 9th Embodiment of this invention. It is sectional drawing which shows the high pressure pump by 10th Embodiment of this invention. It is sectional drawing which shows the high pressure pump by 11th Embodiment of this invention. It is sectional drawing which shows the high pressure pump by 12th Embodiment of this invention. It is sectional drawing which shows the high pressure pump by 13th Embodiment of this invention. It is explanatory drawing which shows the stopper of the plunger by 13th Embodiment. It is explanatory drawing which shows the stopper of the modification 1 of 13th Embodiment. It is explanatory drawing which shows the stopper of the modification 2 of 13th Embodiment. It is explanatory drawing which shows the stopper of the modification 3 of 13th Embodiment.

  A plurality of embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
A high-pressure pump according to a first embodiment of the present invention is shown in FIG. The high-pressure pump 10 is a pump that supplies fuel to an injector of a diesel engine or a gasoline engine, for example.

The plunger 14 has a different diameter structure having a sliding portion 15 and a small diameter portion 16 having a smaller diameter than the sliding portion 15. A step 17 is formed between the sliding portion 15 and the small diameter portion 16 due to the different diameters. The sliding portion 15 is supported by the cylinder 22 so as to be reciprocally movable. The small-diameter portion 16 is installed on the opposite side of the pressurizing chamber 304 with respect to the sliding portion 15, and the periphery of the small-diameter portion 16 is sealed with an oil seal 19 that is a seal member. The small diameter portion 16 of the plunger 14 is in contact with the tappet 12. Since the tappet 12 is pressed toward the cam 2 by the biasing force of the spring 18, the outer bottom surface of the tappet 12 slides with the cam 2 when the cam 2 rotates. Therefore, the plunger 14 reciprocates together with the tappet 12 by the rotation of the cam 2.

  The pump housing 20 has a cylinder 22 that supports the plunger 14 so as to be reciprocally movable. In the pump housing 20, an inlet passage 300, a suction chamber 302, a pressurization chamber 304, a fuel chamber 308 and a communication passage 310 are formed. Fuel supplied to the high-pressure pump 10 from a low-pressure pump (not shown) is introduced into the suction chamber 302 from an inlet passage 300 that is a fuel inlet.

  The suction chamber 302 and the pressurizing chamber 304 communicate with each other through a communication hole 306 formed on the inner peripheral side of the valve seat 35 in a state where the valve member 32 of the metering valve 30 is separated from the valve seat 35. The fuel chamber 308 is partitioned from the pressurizing chamber 304 by a sliding portion between the sliding portion 15 and the cylinder 22. The fuel chamber 308 is a descending space formed on the descending side of the step 17 and is formed around the small diameter portion 16 between the sliding portion between the sliding portion 15 and the cylinder 22 and the oil seal 19. Yes. The upper portion of the fuel chamber 308 is sealed by a sliding portion between the sliding portion 15 and the cylinder 22, and the lower portion of the fuel chamber 308 is sealed by a sliding portion between the small diameter portion 16 and the oil seal 19. The communication path 310 communicates the suction chamber 302 and the fuel chamber 308. The communication passage 310 is also a discharge passage for discharging fuel from the suction chamber 302 to the fuel chamber 308.

  The metering valve 30 includes a valve member 32, a spring 33, a coil 34, a valve seat 35, and a stopper 40. The stopper 40 is provided on the fuel downstream side of the valve member 32. As shown in FIG. 1B, four notches are formed on the outer periphery of the stopper 40. Due to this notch, a fuel passage 42 is formed between the stopper 40 and the inner peripheral surface of the pump housing 20.

  The valve member 32 is urged by the urging force of the spring 33 in the direction away from the stopper 40, that is, the valve seat 35. When energization of the coil 34 is turned on, the valve member 32 is seated on the valve seat 35 by the magnetic attractive force against the urging force of the spring 33. When the valve member 32 is seated on the valve seat 35, the communication hole 306 is closed, so that the communication between the suction chamber 302 and the pressurizing chamber 304 is blocked.

  The low pressure damper 50 has, for example, a diaphragm or the like inside, and reduces pressure pulsations generated in the inlet passage 300 and the suction chamber 302.

  The ball 62 of the discharge valve 60 is separated from the valve seat 64 against the urging force of the spring 63 when the pressure in the pressurizing chamber 304 exceeds a predetermined pressure. When the ball 62 is separated from the valve seat 64, the fuel in the pressurizing chamber 304 is discharged from the discharge valve 60.

  Next, the operation of the high-pressure pump 10 will be described.

(1) Suction stroke As shown in FIG. 2, when the plunger 14 descends from the top dead center toward the bottom dead center with the rotation of the cam 2, the energization to the coil 34 is turned off. Therefore, the valve member 32 is separated from the valve seat 35 by the urging force of the spring 33, and the suction chamber 302 and the pressurizing chamber 304 communicate with each other through the communication hole 306. Accordingly, fuel is sucked from the suction chamber 302 into the pressurization chamber 304 as the plunger 14 is lowered.

  Further, when the plunger 14 is lowered, the step 17 of the plunger 14 formed between the sliding portion 15 and the small diameter portion 16 moves to the fuel chamber 308 side, so that the volume of the fuel chamber 308 decreases. Due to the reduction in the volume of the fuel chamber 308, the fuel in the fuel chamber 308 is pushed out to the communication path 310 and introduced into the suction chamber 302 from the communication path 310.

  As described above, as the plunger 14 is lowered, the fuel is introduced from the fuel chamber 308 through the communication path 310 to the suction chamber 302 when the fuel is sucked from the suction chamber 302 into the pressurizing chamber 304. The pressure drop in the suction chamber 302 can be reduced. Therefore, it is possible to prevent a fuel intake failure into the pressurizing chamber 304 due to a pressure drop in the suction chamber 302 and to suck a necessary amount of fuel from the suction chamber 302 into the pressurizing chamber 304.

(2) Return stroke As shown in FIG. 1, when the plunger 14 rises from the bottom dead center toward the top dead center, the valve member is urged by the urging force of the spring 33 while the coil 34 is energized. 32 remains separated from the valve seat 35. Therefore, as the plunger 14 moves up, the fuel in the pressurizing chamber 304 is returned to the suction chamber 302 through the communication hole 306. At this time, since the step 17 formed between the sliding portion 15 and the small diameter portion 16 is raised, the volume of the fuel chamber 308 is increased. As a result, part of the fuel returned from the pressurizing chamber 304 to the suction chamber 302 passes through the communication path 310 and is discharged to the fuel chamber 308.

  Thus, as the plunger 14 moves up, the fuel is discharged from the suction chamber 302 through the communication path 310 to the fuel chamber 308 when the fuel is returned from the pressurizing chamber 304 to the suction chamber 302. An increase in pressure in the suction chamber 302 due to the rise can be reduced.

(3) When energization of the coil 34 is turned on during the pressurization stroke return stroke, the valve member 32 is attracted by the magnetic attraction force against the urging force of the spring 33, and the valve member 32 is seated on the valve seat 35. As a result, the communication hole 306 is closed and the communication between the suction chamber 302 and the pressurizing chamber 304 is blocked, so that the fuel in the pressurizing chamber 304 is pressurized and the fuel pressure rises as the plunger 14 moves up. When the fuel pressure in the pressurizing chamber 304 becomes equal to or higher than a predetermined pressure, the ball 62 is separated from the valve seat 64 against the biasing force of the spring 63, and the discharge valve 60 is opened. Thereby, the fuel pressurized in the pressurizing chamber 304 is discharged from the high-pressure pump 10.

  The amount of fuel discharged from the high-pressure pump 10 is metered at the timing when the energization of the coil 34 is turned on and the metering valve 30 is closed when the plunger 14 is raised. Then, by repeating the steps (1), (2), and (3), the high-pressure pump 10 repeats the intake and discharge of fuel.

  In the first embodiment, the pressure drop in the suction chamber 302 is reduced by introducing fuel from the fuel chamber 308 to the suction chamber 302 during the suction stroke. Thereby, in the intake stroke, it is possible to prevent a poor intake of fuel from the suction chamber 302 to the pressurization chamber 304 and to suck a necessary amount of fuel from the suction chamber 302 to the pressurization chamber 304.

  In the return stroke, the pressure in the suction chamber 302 is reduced by discharging the fuel from the suction chamber 302 to the fuel chamber 308. Thereby, the pressure pulsation of the suction chamber 302 caused by the plunger 14 repeatedly moving up and down is reduced. If the pressure pulsation in the suction chamber 302 is reduced, it is possible to prevent a poor intake of fuel from the suction chamber 302 to the pressurization chamber 304 during the suction stroke and to suck a necessary amount of fuel from the suction chamber 302 into the pressurization chamber 304.

  Further, the pressure pulsation in the suction chamber 302 is reduced, and the pressure fluctuation applied to the fuel pipe on the low pressure damper 50 and the suction chamber 302 side is reduced. Therefore, damage to the low pressure damper 50 and the fuel pipe can be prevented. Further, since vibration of the fuel pipe due to pressure pulsation is reduced, loosening of the support portion of the fuel pipe can be prevented.

(Second, third and fourth embodiments)
FIG. 3 shows a second embodiment of the present invention, FIG. 4 shows a third embodiment, and FIG. 5 shows a fourth embodiment. In addition, the same code | symbol is attached | subjected to the substantially same component as 1st Embodiment, and description is abbreviate | omitted.

  In the high pressure pump 70 of the second embodiment shown in FIG. 3, an annular plate 72 is installed on the cylinder 22 side of the oil seal 19 so as to surround the small diameter portion 16 of the plunger 14. A small gap 74 is formed between the inner peripheral edge of the plate 72 and the outer peripheral surface of the small diameter portion 16 so as not to prevent the small diameter portion 16 from reciprocating. Due to the gap 74, for example, foreign matters such as sliding dust generated from the sliding portion between the sliding portion 15 and the cylinder 22 are prevented from entering the sliding portion between the oil seal 19 and the small diameter portion 16. Thereby, damage to the oil seal 19 can be prevented.

  In the high-pressure pump 80 of the third embodiment shown in FIG. 4, a filter 82 that removes foreign matters is installed in the middle of the communication path 310. The filter 82 prevents foreign matters in the fuel supplied to the high pressure pump 80 from entering the sliding portion between the oil seal 19 and the small diameter portion 16 through the communication path 310. Thereby, damage to the oil seal 19 can be prevented.

  In the high pressure pump 90 of the fourth embodiment shown in FIG. 5, the fuel chamber 308 is formed not in the vicinity of the small diameter portion 16 of the plunger 14 but in the middle of the communication path 310. The fuel chamber 308 communicates with the descending space 312 of the step 17. Even if the formation position of the fuel chamber 308 is changed in this way, as in the first embodiment, the pressure in the suction chamber 302 is prevented from lowering during the suction stroke, and is generated in the suction chamber 302 as the plunger 14 reciprocates. Pressure pulsation can be reduced.

(Fifth embodiment)
A fifth embodiment of the present invention is shown in FIG. In addition, the same code | symbol is attached | subjected to the substantially same component as 1st Embodiment, and description is abbreviate | omitted.

  In the high pressure pump 100 of the fifth embodiment shown in FIG. 6, the valve member 104 of the metering valve 102 is biased toward the valve seat 106 by the biasing force of the spring 33. In the state where the power supply to the coil 34 is turned off, the valve member 104 is seated on the valve seat 106 by the urging force of the spring 33, so that the communication hole 306 formed on the inner peripheral side of the valve seat 106 is closed, and the suction chamber Communication between 302 and the pressurizing chamber 304 is blocked. When energization of the coil 34 is turned on, the valve member 104 is attracted against the urging force of the spring 33 and is separated from the valve seat 106. Thereby, the suction chamber 302 and the pressurizing chamber 304 communicate with each other.

  A suction valve 110 is installed in a suction passage 314 that connects the suction chamber 302 and the pressurizing chamber 304. The ball 112 of the suction valve 110 is urged toward the valve seat 114 by a spring 113. The suction valve 110 is a check valve that permits fuel flow from the suction chamber 302 to the pressurization chamber 304 and prohibits fuel flow from the pressurization chamber 304 to the suction chamber 302.

  Next, the operation of the high pressure pump 100 in the fifth embodiment will be described.

(1) When the suction stroke plunger 14 is lowered and the pressure in the pressurizing chamber 304 is lowered, the ball 112 of the suction valve 110 is separated from the valve seat 114 against the urging force of the spring 113. When the ball 112 is separated from the valve seat 114, the fuel in the suction chamber 302 passes through the suction passage 314 and is sucked into the pressurization chamber 304. Further, when the plunger 14 is lowered, the fuel in the fuel chamber 308 is introduced into the suction chamber 302 from the communication path 310.

  As described above, since the fuel in the suction chamber 302 can be sucked into the pressurization chamber 304 from the suction valve 110 in the suction stroke, the metering valve 102 may be in the open or closed state.

(2) Return stroke When the plunger 14 starts to rise from the bottom dead center toward the top dead center, the coil 34 is energized and the valve member 32 is separated from the valve seat 106. As a result, even if the plunger 14 is raised, the fuel in the pressurizing chamber 304 is returned to the suction chamber 302 through the communication hole 306. Further, the fuel returned to the suction chamber 302 is discharged to the fuel chamber 308 through the communication path 310.

(3) When the energization of the coil 34 is turned off during the pressurization stroke return stroke, the valve member 104 is seated on the valve seat 106 by the urging force of the spring 33, the communication hole 306 is closed, and the suction chamber 302 and the pressurization chamber 304 are closed. Communication with is interrupted. Since the valve opening pressure of the metering valve 102 is higher than the valve opening pressure of the discharge valve 60, when the fuel pressure in the pressurizing chamber 304 exceeds a predetermined pressure due to the rise of the plunger 14, the discharge valve 60 opens and the metering valve The valve 102 remains closed. When the discharge valve 60 is opened, the fuel pressurized in the pressurizing chamber 304 is discharged from the high-pressure pump 100.

(Sixth embodiment)
A sixth embodiment of the present invention is shown in FIG. In addition, the same code | symbol is attached | subjected to the substantially same component as 1st Embodiment, and description is abbreviate | omitted.

  In the metering valve 122 of the high pressure pump 120 of the sixth embodiment shown in FIG. 7, the bottom wall of the cup-shaped valve member 126 is in contact with the end of the shaft 124. The spring 128 biases the valve member 126 in the direction opposite to the spring 33. Since the urging force of the spring 33 is larger than the urging force of the spring 128, the valve member 126 is separated from the valve seat 35 in a state where the energization to the coil 34 is turned off.

  When energization of the coil 34 is turned on while the plunger 14 is raised, the shaft 124 is raised by the magnetic attractive force, and the valve member 126 is seated on the valve seat 35 by the biasing force of the spring 128. As a result, the fuel in the pressurizing chamber 304 is pressurized.

(Seventh embodiment)
A seventh embodiment of the present invention is shown in FIG. In addition, the same code | symbol is attached | subjected to the substantially same component as 1st Embodiment, and description is abbreviate | omitted.

  In the metering valve 132 of the high pressure pump 130 of the seventh embodiment shown in FIG. 8, the coil 34 is installed on the outer peripheral side of the stopper 40. The stopper 40 is formed, for example, by coating the surface of a magnetic material with a nonmagnetic material. The valve member 126 is formed by, for example, coating a magnetic material or the surface of the magnetic material with a nonmagnetic material.

  The spring 128 biases the valve member 126 toward the valve seat 35. When energization of the coil 34 is turned on, a magnetic attractive force acts between the valve member 126 and the stopper 40 in the direction opposite to the biasing direction of the spring 128.

  Next, the operation of the high pressure pump 130 of the seventh embodiment will be described.

(1) When the suction stroke plunger 14 descends and the pressure in the pressurizing chamber 304 decreases, the differential pressure received by the valve member 126 from the suction chamber 302 upstream of the valve member 126 and the pressurization chamber 304 downstream. Changes. The sum of the force received in the direction in which the valve member 126 is seated on the valve seat 35 by the fuel pressure in the pressurizing chamber 304 and the urging force of the spring 128 is calculated by the fuel pressure on the suction chamber 302 side. The valve member 126 is separated from the valve seat 35 and is locked to the stopper 40 when it becomes smaller than the force received in the direction of separating from the valve seat. As a result, fuel is sucked from the suction chamber 302 into the pressurization chamber 304. Even in a state where the valve member 126 is locked to the stopper 40, the fuel passage 42 is formed around the contact portion between the valve member 126 and the stopper 40, so that the valve member 126 is opposite to the valve member 126 with the stopper 40 interposed therebetween. Fuel is sucked through the fuel passage 42 into the pressurizing chamber 304 on the plunger 14 side.

  Then, energization of the coil 34 is turned on while the stopper 40 and the valve member 126 before the plunger 14 reaches bottom dead center are in contact with each other. Since the stopper 40 and the valve member 126 are in contact with each other, the magnetic attraction force required for maintaining the valve-opening state of the metering valve 132 with the valve member 126 locked to the stopper 40 may be small.

(2) Return stroke Even if the plunger 14 rises from the bottom dead center toward the top dead center, the energization of the coil 34 is in an on state, and a magnetic attraction force is generated between the stopper 40 and the valve member 126. Since the valve member 126 is working, the valve member 126 is held in the valve open position locked to the stopper 40. As a result, the open state of the communication hole 306 is maintained, so that the fuel in the pressurization chamber 304 pressurized by the rise of the plunger 14 is returned to the suction chamber 302 through the communication hole 306.

(3) If energization of the coil 34 is turned off during the pressurization stroke return stroke, the magnetic attractive force does not work between the valve member 126 and the stopper 400. As a result, the sum of the force that the valve member 126 receives in the direction in which the valve member 126 is seated on the valve seat 35 due to the fuel pressure in the pressurizing chamber 304 and the biasing force of the spring 128 is It becomes larger than the force received in the direction away from 35. As a result, the valve member 126 is seated on the valve seat 35 by the differential pressure, and the communication hole 306 is closed. When the plunger 14 further rises toward the top dead center in this state, the fuel in the pressurizing chamber 304 is pressurized and the fuel pressure rises. When the fuel pressure in the pressurizing chamber 304 becomes equal to or higher than a predetermined pressure, the ball 62 is separated from the valve seat 64 against the biasing force of the spring 63, and the discharge valve 60 is opened. As a result, the fuel pressurized in the pressurizing chamber 304 is discharged from the discharge valve 60.

(Eighth, ninth and tenth embodiments)
FIG. 9 shows an eighth embodiment of the present invention, FIG. 10 shows a ninth embodiment, and FIG. 11 shows a tenth embodiment. In the eighth, ninth, and tenth embodiments, the shape of the valve member or stopper of the metering valve of the high-pressure pump is different from that of the seventh embodiment, and other configurations are substantially the same as those of the seventh embodiment. It is a configuration.

  The stoppers 146, 40, and 166 of the eighth, ninth, and tenth embodiments are formed by coating the surface of a magnetic material with a nonmagnetic material, for example. Further, the valve members 144 and 154 and the cylindrical member 165 are formed, for example, by coating the surface of a magnetic material or a magnetic material with a nonmagnetic material. Accordingly, when energization of the coil 34 is turned on, a magnetic attractive force acts between the stopper 146 and the valve member 144, the stopper 40 and the valve member 154, and the stopper 166 and the cylindrical member 165.

  In the high-pressure pump 140 of the eighth embodiment shown in FIG. 9, the stopper 146 and the valve member 144 of the metering valve 142 have protrusions that protrude toward each other, and these protrusions are Abut.

  In the high-pressure pump 150 of the ninth embodiment shown in FIG. 10, the valve member 154 of the metering valve 152 is formed in a cup shape, and has a flange that extends outward on the opening side facing the stopper 40. Thereby, since the area of the valve member 154 latched by the stopper 40 increases, it is suppressed that the valve member 154 inclines in the state latched by the stopper 40.

  In the high-pressure pump 160 of the tenth embodiment shown in FIG. 11, a recess for locking the spring 128 is formed on the stopper 166 of the metering valve 162. The ball 164 and the cylindrical member 165 constitute a valve member.

(11th and 12th embodiments)
An eleventh embodiment of the present invention is shown in FIG. 12, and a twelfth embodiment is shown in FIG. The configurations of the eleventh and twelfth embodiments are substantially the same except that the shapes of the valve members 126 and 154 are different. The operation of the valve members 126 and 154 and the timing of energizing the coil 34 are the same as those in the seventh to tenth embodiments. In the eleventh and twelfth embodiments, substantially the same components as those in the seventh to tenth embodiments are denoted by the same reference numerals, and description thereof is omitted.

  In the high-pressure pump 170 of the eleventh embodiment shown in FIG. 12 and the high-pressure pump 180 of the twelfth embodiment shown in FIG. 13, the metering valves 172 and 182 and the plunger 14 are installed with their axes shifted. The stoppers 174 of the valve members 126 and 154 of the metering valves 172 and 182 are formed by a part of the pump housing 20. The stopper 174 provided on the pump housing 20 is formed, for example, by coating the surface of a magnetic material with a nonmagnetic material. Therefore, when energization of the coil 34 is turned on, a magnetic attraction force acts between the valve members 126 and 154 and the stopper 174.

(13th Embodiment)
A thirteenth embodiment of the present invention is shown in FIG. In addition, the same code | symbol is attached | subjected to the substantially same component as 1st Embodiment, and description is abbreviate | omitted.

  In the high pressure pump 190 of the thirteenth embodiment, a C-shaped stopper 192 shown in FIG. 15 is fitted to the inner wall of the cylinder 22 on the descending side of the step 17 of the plunger 14. The stopper 192 is installed closer to the tappet 12 than the lowest point of the step 17, and protrudes to the inner peripheral side from the inner peripheral surface of the cylinder 22. According to this configuration, for example, when the sliding portion 15 is lowered with the high-pressure pump 190 removed from the cam 2, the step 17 is locked to the stopper 192. This prevents the step 17 from colliding with the oil seal 19 and damaging the oil seal 19.

(Deformation 1, 2, 3)
Instead of the stopper 192 of the thirteenth embodiment, the step 17 of the plunger 14 may be locked using stoppers 194, 196, and 198 having the shapes shown in FIGS. All of the stoppers 194, 196, 198 are formed in a C shape and are fitted to the inner wall of the cylinder 22 on the descending side of the step 17 of the plunger 14. Each of the stoppers 194, 196, 198 is installed on the tappet 12 side from the lowest point of the step 17.

  In the thirteenth embodiment and the first, second, and third modifications, the stoppers 192, 194, 196, and 198 are installed closer to the tappet 12 than the lowest point of the step 17 of the plunger 14, so that the high pressure pump can be removed. The effect of preventing the plunger 14 from dropping off can be expected, and the assembling property to the engine or the like is improved.

  In the above-described plurality of embodiments, the fuel chamber partitioned from the pressurizing chamber 304 by the sliding portion between the sliding portion 15 of the plunger 14 and the cylinder 22 is provided, and the communication chamber 310 connects the suction chamber 302 and the fuel chamber. It communicates with. Further, since the small diameter portion 16 having a smaller diameter than the sliding portion 15 is formed on the lower side of the sliding portion 15, a step 17 is formed between the sliding portion 15 and the small diameter portion 16 due to the difference in diameter. Yes.

  Therefore, when the plunger 14 descends, the volume of the fuel chamber or descending space provided on the descending side of the step 17 decreases, so that the fuel in the fuel chamber is pushed out to the communication passage 310 and introduced into the suction chamber 302. Since the volume of the fuel chamber or the space on the descending side decreases following the descending speed of the plunger 14, even if the rotational speed of the high pressure pump increases and the reciprocating speed of the plunger 14 increases, Fuel can be introduced into the suction chamber 302. As a result, a decrease in fuel pressure in the suction chamber 302 during the suction stroke can be reduced.

  Further, when the plunger 14 rises and the end surface of the sliding portion 15 in the reciprocating direction moves to the pressurizing chamber 304 side, the volume of the pressurizing chamber 304 decreases, so that the pressurizing chamber 304 is returned to the suction chamber 302. The fuel is pushed out to the communication path 310 and discharged into the fuel chamber. Thereby, the pressure rise of the suction chamber 302 when the plunger 14 is raised is reduced, and the pressure pulsation of the suction chamber 302 caused by the plunger 14 is repeatedly raised and lowered is reduced.

  In this way, by reducing the pressure drop in the suction chamber 302 and the pressure pulsation generated in the suction chamber 302, it is possible to prevent a poor intake of fuel from the suction chamber 302 to the pressurizing chamber 304 during the suction stroke, and to reduce the required amount. Fuel can be sucked into the pressurizing chamber 304. Moreover, since pressure pulsation generated in the suction chamber 302 is reduced, an increase in pressure in the suction chamber 302 can be reduced. Therefore, it is possible to prevent the low pressure damper 50 and the fuel pipe installed on the fuel inlet side from being damaged by the high pressure. Further, since the vibration of the fuel pipe is suppressed by reducing the pressure pulsation in the suction chamber 302, it is possible to prevent loosening of the support portion that supports the fuel pipe.

(Other embodiments)
In the above embodiments, when the plunger 14 is raised, the fuel in the suction chamber 302 is discharged to the fuel chamber through the communication passage 310, and when the plunger 14 is lowered, the fuel in the fuel chamber is passed through the communication passage 310 to the suction chamber 302. Introduced.

  In contrast, when the plunger is lowered, fuel is introduced from the fuel chamber through the communication passage into the suction chamber. However, when the plunger is raised, fuel may not be discharged from the suction chamber through the communication passage into the fuel chamber. .

  For example, the plunger has the same diameter without forming a step, and when the plunger is raised, the fuel is discharged from the suction chamber to the fuel chamber through the communication passage, but when the plunger is lowered, the fuel is introduced from the fuel chamber to the suction chamber. You may make it the structure which is not carried out.

  Further, a configuration may be employed in which a fuel passage is not formed and a discharge passage communicating with the suction chamber 302 is provided separately from the inlet passage 300, and fuel in the suction chamber is discharged from the suction chamber through the discharge passage when the plunger is lifted.

  10, 70, 80, 90, 100, 120, 130, 140, 150, 160, 170, 180, 190 High pressure pump, 14 Plunger, 15 Sliding part, 16 Small diameter part, 17 Step, 19 Oil seal, 22 Cylinder, 30, 102, 122, 132, 142, 152, 162, 172, 182 Metering valve, 300 Inlet passage (fuel inlet), 302 Suction chamber, 304 Pressurizing chamber, 308 Fuel chamber, 310 Communication passage, 312 Lowering space

Claims (6)

In a high pressure pump that introduces fuel into a suction chamber from a fuel inlet and pressurizes and discharges fuel sucked into the pressurization chamber from the suction chamber.
A plunger that pressurizes fuel sucked from the suction chamber into the pressurization chamber by reciprocating; and
A cylinder that reciprocally supports the plunger;
A metering valve for intermittently communicating between the suction chamber and the pressurizing chamber and metering a fuel discharge amount;
A fuel chamber whose volume changes according to the operation of the plunger;
A discharge passage communicating the suction chamber and the fuel chamber;
A discharge valve for discharging fuel pressurized by the plunger,
When the plunger is lowered and fuel is sucked into the pressurizing chamber from the suction chamber, the volume of the fuel chamber decreases, so that fuel is introduced from the fuel chamber into the suction chamber,
On the other hand, when the plunger is raised and fuel is returned from the pressurizing chamber to the suction chamber, the volume of the fuel chamber increases, so that a part of the fuel returned to the suction chamber is part of the discharge passage. Is discharged into the fuel chamber through
A valve member that interrupts communication between the suction chamber and the pressurizing chamber; a valve seat on which the valve member is separated; and a spring that biases the valve member in a direction in which the valve member is seated on the valve seat; The metering valve having a coil that is turned on and off, and a shaft that is magnetically attracted by energizing the coil,
When the plunger starts to rise from the bottom dead center to the top dead center, the energization to the coil is turned off, so that the valve member abutted on the shaft is separated from the valve seat. , Communicating the suction chamber and the pressurizing chamber,
On the way to the top dead center, energization of the coil is turned on to magnetically attract the shaft, and the valve member is seated on the valve seat by the urging force of the spring, and the suction chamber A high-pressure pump characterized in that the pressure chamber is shut off.   The metering valve includes a first spring as the spring, and a second spring that biases the shaft with a force larger than the biasing force of the first spring in a direction in which the valve member separates from the valve seat. The high pressure pump according to claim 1, further comprising: The valve member is disposed in the pressurizing chamber;
The shaft passes through the suction chamber;
The high-pressure pump according to claim 1 or 2, wherein the coil is disposed on the opposite side of the pressurizing chamber with the suction chamber interposed therebetween. The valve member is disposed in the pressurizing chamber;
A communication hole communicating the suction chamber and the pressurizing chamber is formed on the inner peripheral side of the valve seat;
The high pressure according to any one of claims 1 to 3, wherein the shaft contacts the valve member from the suction chamber side through the communication hole to separate the valve member from the valve seat. pump.   5. The high-pressure pump according to claim 1, wherein an end portion of the shaft is brought into contact with a bottom wall of the cup-shaped valve member from the valve seat side. The metering valve has a stopper disposed in the pressurizing chamber together with the valve member,
The high pressure pump according to claim 3, wherein the spring is interposed between the valve member and the stopper in the pressurizing chamber.

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