JP2011163173A - High pressure pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a normal close type high pressure pump having improved responsiveness at high speed rotation. <P>SOLUTION: In the normal close type high pressure pump, a needle 61 installed integrally with a movable core 53 abuts against a valve member 21 by biasing force of a needle spring 56 when an electromagnetic actuator 50 is not energized and advances by electromagnetic attraction force upon energization. The needle 61 has a flange portion 611 having the outer diameter slightly smaller than the inner diameter of a valve cylindrical part 232. When the pressure in a pressurization chamber 95 is reduced and the valve member 21 is opened in a suction process at high speed rotation, fuel flows through a throttle flow passage 931 in a gap between the flange portion 611 and the valve cylindrical part 232 to generate a differential pressure, and the advancing operation of the needle 61 is assisted by the differential pressure. With this, the valve member 21 can be opened surely and the responsiveness at high speed rotation is improved. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a high-pressure pump used for an engine.

  Conventionally, a fuel supply device that supplies fuel to an engine is provided with a high-pressure pump that pumps high-pressure fuel. In general, a high-pressure pump reciprocates a plunger according to the rotation of an engine, and repeats a process cycle including a suction process, a metering process, and a pressurization process, whereby fuel sucked from a fuel tank is connected to an injector. To discharge.

In order to create the above process cycle, it is necessary to control the opening and closing of the intake valve in synchronization with the reciprocating movement of the plunger. Specifically, (1) the plunger is lowered and the fuel is sucked in with the intake valve open, and (2) the plunger is lifted up to the middle of the stroke while the intake valve is open to return a part of the fuel. And (3) repeat the process cycle in which the suction valve closes and the plunger raises the rest of the stroke to pressurize and discharge.
Here, proper metering is realized by adjusting the switching timing from the metering step (2) to the pressurizing step (3).

  In general, a suction valve of a high-pressure pump is configured to open and close by a combination of a spring and a solenoid. High-pressure pumps are classified into a normally open type and a normally closed type depending on the relationship between energization and non-energization of the solenoid and the opening and closing of the intake valve.

The normally open high-pressure pump is opened by a biasing force of a spring when the solenoid is not energized, and is closed by a needle that moves integrally with the movable core while the solenoid is energized. Therefore, the metering process shifts to the pressurization process by the energization ON command.
The normally closed type high-pressure pump is closed by a needle that moves integrally with the movable core while the solenoid is energized and is closed by the biasing force of the spring. Therefore, the metering process shifts to the pressurization process by the energization OFF command.
The normally closed type high pressure pump can reduce the driving power compared to the normally open type high pressure pump.

  Here, regarding the configuration of the needle and the suction valve, for example, in the high-pressure fuel pump of Patent Document 1, as shown in FIG. 18, the needle and the suction valve have separate structures. The needle 57 is assembled integrally with the movable core 53 of the electromagnetic drive unit 50, and the movable core 53 is biased toward the valve member 41 by the biasing force of the spring 56. When the coil 51 is not energized, the end of the needle 57 opposite to the movable core 53 comes into contact with the valve member 41, and the needle 57 pushes the valve member 41 in a direction away from the valve seat portion 32, thereby inhaling. The valve opens. When the coil 51 is energized, an electromagnetic attractive force is generated between the movable core 53 and the fixed core 52, and the movable core 53 moves toward the fixed core 52 against the urging force of the spring 56. Then, the end portion of the needle 57 is separated from the valve member 41, and the valve member 41 is seated on the valve seat portion 32 by the biasing force of the spring 43, thereby closing the intake valve.

Thus, the high-pressure fuel pump of Patent Document 1 has a normally open type configuration. However, the arrangement can be easily changed to a normally closed configuration by changing the arrangement so that the electromagnetic attracting force of the solenoid and the biasing force of the spring act in the opposite directions.
Patent Document 2 discloses a high-pressure fuel pump in which a needle and a suction valve are integrated.

Japanese Patent No. 4318730 JP 2009-185613 A

In a high-pressure pump that opens and closes the suction valve using the electromagnetic suction force of the solenoid, there is a slight response time until the electromagnetic suction force is sufficiently generated from the energization command to the solenoid. Since the process cycle time is sufficiently longer than the response time during low-speed rotation, the process switching timing is hardly affected.
On the other hand, during high-speed rotation, the process cycle time can be comparable to the response time of the electromagnetic attractive force. Then, the response of the needle operation due to the electromagnetic attractive force may not be in time for the process switching timing.

In the case of a normally closed type high-pressure pump based on Patent Document 1, the energization command is turned on immediately after the start of the intake process until the end of the metering process, and the intake valve can be kept open according to the energization command. Required. However, a sufficient electromagnetic attractive force cannot be obtained during the response time of the electromagnetic attractive force, and the operation of the needle may be delayed. Furthermore, if sufficient electromagnetic attractive force is not obtained even in the metering step, the needle is pushed back by the flow of fuel, and the intake valve may be closed. Then, before the energization command is turned off, the metering process is substantially finished. Therefore, there is a problem that the metering as intended is not possible and excessive fuel is discharged.
If excessive fuel is discharged, the pressure on the fuel rail will increase, reducing the injection accuracy of the injector, and if it increases further, the injector will not be able to inject. Further, the pressure in the fuel rail may rise abnormally beyond the allowable range, and the fuel rail and the injector may be damaged.

  Moreover, in patent document 2, the responsiveness at the time of high-speed rotation is improved by integrating a needle and a suction valve. However, high precision coaxial processing of the needle sliding portion, the valve seat, and the valve sliding portion is necessary, which leads to an increase in cost.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a high-pressure pump that improves responsiveness during high-speed rotation without increasing cost in a normally closed high-pressure pump. .

The high-pressure pump according to claim 1 includes a plunger, a housing, a cylindrical member, a seat portion, a valve member, a needle, a needle spring, an electromagnetic actuator, a valve spring, and a throttle portion.
The plunger can reciprocate.
The housing has a pressurizing chamber and an upstream chamber. The pressurizing chamber changes its volume by the movement of the plunger and can pressurize the fuel. The upstream chamber is provided on the upstream side of the pressurizing chamber.
The cylindrical member is provided in the housing and has an upstream passage for introducing fuel from the upstream chamber to the pressurizing chamber.
The annular sheet portion is provided on the upstream side of the pressurizing chamber and on the downstream side of the cylindrical member.
The valve member blocks or communicates with the upstream passage by being seated on or separated from the seat portion.

The needle is disposed on the upstream side of the valve member and includes a first small diameter portion and a large diameter portion. The first small diameter portion can contact the upstream end surface of the valve member. The large diameter portion has a larger diameter than the first small diameter portion, and continues to the upstream side of the first small diameter portion within the range of the upstream passage.
The needle spring biases the first small diameter portion so as to contact the upstream end surface of the valve member.
The electromagnetic actuator is connected to an end portion of the needle opposite to the first small diameter portion, and generates an electromagnetic attractive force so as to move the needle in the valve opening direction during operation.
The valve spring has a larger set load than the needle spring, and biases the valve member in the valve closing direction when the electromagnetic actuator is not operated.
As described above, a normally closed high-pressure pump is configured.

The restricting portion reduces the channel cross-sectional area from the upstream side to the downstream side in the upstream passage.
The large diameter portion continues to the upstream side of the first small diameter portion within the range of the upstream passage. Therefore, the outer periphery of the large diameter portion overlaps with the inner periphery of the cylindrical member in the axial direction at least at a part in the axial direction. A gap between the large diameter portion and the cylindrical member is generated in the overlapping portion. Therefore, by setting the outer diameter of the large diameter portion slightly smaller than the inner diameter of the cylindrical member, this gap can be used as the throttle portion. Note that the cross-sectional area of the gap is at least equal to or larger than the cross-sectional area necessary for flowing the required flow rate.
Alternatively, the throttle portion may pass through the large diameter portion and communicate from the upstream side to the downstream side.
Here, the shape of the large diameter portion is not limited outside the range of the upstream passage. For example, the large diameter portion may extend upstream with the same diameter, or the diameter may change on the upstream side.

By providing the throttle part, a differential pressure is generated between the upstream side and the downstream side of the throttle part. Here, in the following explanation, the oil pressure on the upstream side minus the oil pressure on the downstream side is defined as “differential pressure”. When the upstream oil pressure is relatively high, it is defined as “positive differential pressure”. When the side oil pressure is high, it is expressed as “negative pressure difference”. In the suction process, fuel flows from the upstream side to the downstream side, and a positive differential pressure is generated. In the metering process, fuel flows from the downstream side to the upstream side, and a negative differential pressure is generated. The expression “the negative differential pressure is small” means “the absolute value of the negative differential pressure is small”.
When a positive differential pressure is generated in the suction process, the hydraulic pressure assists the operation in the downstream direction, that is, the forward direction with respect to the needle. Therefore, even when the electromagnetic attractive force cannot be sufficiently obtained at the time of high-speed rotation, the needle can be rapidly advanced by the hydraulic assist force, and the valve member can be held in the valve open state. Therefore, the response at the time of high speed rotation is improved.
Further, since the needle and the valve member constituting the suction valve are manufactured as separate structures, the manufacturing cost does not increase as compared with the case of an integral structure.

The high-pressure pump according to claims 2 to 5 is the high-pressure pump according to claim 1, and the configuration of the throttle portion is embodied.
In the high-pressure pump according to claim 2, the needle includes a second small-diameter portion that is smaller in diameter than the large-diameter portion and continues to the upstream side of the large-diameter portion, and the large-diameter portion has a predetermined thickness in the axial direction. Configure.
The throttle portion is formed in a gap between the flange portion and the cylindrical member.

  As described above, the outer periphery of the large diameter portion overlaps the inner periphery of the cylindrical member in the axial direction within the range of the upstream passage. In this case, it is sufficient to overlap within a range of a predetermined length for forming the throttle portion. Therefore, the needle can be reduced in weight by narrowing the upstream side as the second small diameter portion. By reducing the weight of the needle, the operability of the needle by the hydraulic assist force and the electromagnetic attraction force is improved, so that the responsiveness at high speed rotation is further improved.

In the high pressure pump according to the third aspect, the brim portion has a chamfered portion that is inclined from the radially inner side of the downstream side surface toward the outer peripheral surface toward the upstream side.
With this configuration, during the metering process in which the fuel returns from the downstream side to the upstream side, the fuel flows from the downstream side of the flange portion to the throttle portion along the chamfered portion, so that it easily flows and the generated negative differential pressure is reduced. . Therefore, the force acting on the needle in the upstream direction, that is, the backward direction is relatively small, and the needle can be stably maintained at the forward limit. Therefore, the valve member can be stably held in the valve open state until the end of the metering step. Therefore, it is possible to perform metering as intended, and the responsiveness during high-speed rotation is further improved.

In the high-pressure pump according to the fourth aspect, the brim portion has an orifice communicating the upstream side and the downstream side.
When the narrowed portion is formed in the gap between the flange portion and the cylindrical member, the cross-sectional area of the gap is likely to vary, and it is relatively difficult to set the dimensions to secure the cross-sectional area necessary for flowing the required flow rate. Therefore, the necessary cross-sectional area can be easily ensured by appropriately providing a small-diameter hole penetrating the collar portion.

In the high-pressure pump according to the fifth aspect, the brim portion has a taper portion that extends toward the opening side in the opening on the downstream side of the orifice.
With this configuration, during the metering step in which the fuel returns from the downstream side to the upstream side, the fuel flows into the orifice along the chamfered portion from the downstream side, so that it easily flows and the generated negative differential pressure is reduced. Therefore, the force acting on the needle in the upstream direction, that is, the backward direction is relatively small, and the needle can be stably maintained at the forward limit. Therefore, the valve member is kept open and the metering can be performed as intended.

  The high-pressure pump according to claim 6 includes a plunger, a housing, a cylindrical member, a seat portion, a valve member, a needle, a movable plate, a needle spring, an electromagnetic actuator, a valve spring, a plate spring, and a throttle portion, and is a normally closed type Of high pressure pump. Here, the configurations of the needle, the movable plate, and the plate spring are different from those of the high-pressure pump according to claim 1.

The needle is disposed on the upstream side of the valve member and includes a first small diameter portion and a second small diameter portion. The first small diameter portion can contact the upstream end surface of the valve member. The second small diameter portion has a smaller diameter than the first small diameter portion, and continues to the upstream side of the first small diameter portion within the range of the upstream passage.
The movable plate is disposed so as to be slidable radially outward of the second small diameter portion and to be regulated by the first small diameter portion.
The plate spring has a smaller set load than the needle spring and biases the movable plate toward the first small diameter portion.
When the fuel flows from the upstream chamber to the pressurizing chamber, the movable plate comes into contact with the first small diameter portion by the urging force of the plate spring. When the fuel flows from the pressurizing chamber to the upstream chamber, the movable plate slides toward the upstream chamber against the urging force of the plate spring by the pressure of the fuel.

With this configuration, in the suction process, the movable plate pushes the first small diameter portion of the needle in the valve opening direction by the urging force of the plate spring and the pressure of the fuel. Moreover, the force which pushes a movable plate to a forward direction acts by a diaphragm effect. Thereby, even if it is a case where electromagnetic attraction force is not fully obtained at the time of high speed rotation, a needle can move forward rapidly and can hold a valve member in a valve-opened state. Therefore, the response at the time of high speed rotation is improved.
In the metering step, the movable plate slides toward the electromagnetic actuator against the urging force of the plate spring by the pressure of the fuel. When the movable plate moves into the upstream chamber beyond the range of the upstream passage, the area of the flow path to the upstream chamber is widened and the throttle effect does not occur. Thereby, the force which pushes back the needle in the backward direction becomes relatively small. Therefore, the valve member can be stably held in the valve open state. Therefore, it is possible to perform metering as intended, and the responsiveness during high-speed rotation is further improved.

The high-pressure pump according to claim 7 is provided with a plunger, a housing, a cylindrical member, a seat part, a valve member, a needle, a needle spring, an electromagnetic actuator, and a valve spring, as in the high-pressure according to claim 1, and is normally closed. Construct a high-pressure pump of the mold.
And it is characterized in that it is provided close to the upstream end surface of the valve member so that the downstream surface of the large diameter portion forms a damper chamber in the gap with the upstream end surface of the valve member. The damper chamber is in a reduced pressure state due to a rapid expansion of the volume when the valve member is opened at high speed.
Here, “closely” means that the gap distance is less than 0.1 mm, for example.

The “damper effect” produced by the damper chamber will be described.
In the suction process during high-speed rotation, the valve member is opened before the needle is advanced by lowering the pressure chamber by lowering the plunger. At this time, the volume of the damper chamber, which is a gap between the downstream surface of the large diameter portion and the upstream surface of the valve member, suddenly expands. The smaller the gap distance is, that is, the smaller the volume of the damper chamber at the time of initial valve closing, the larger the volume change rate. Since this volume change is rapid, the fuel cannot instantaneously flow into the expanded damper chamber, and the damper chamber is in a decompressed state. As a result, a positive differential pressure is generated before and after the brim portion, and an oil pressure in the forward direction acts on the needle. Therefore, even when the electromagnetic attractive force cannot be sufficiently obtained during high-speed rotation, the needle can be rapidly advanced by the hydraulic assist force, and the valve member can be held in the valve open state.

After the valve is opened, the fuel flows at high speed in the axial direction on the outer periphery of the large diameter portion. At this time, due to the Venturi effect based on Bernoulli's theorem, the fuel in the damper chamber located near the high-speed flow is sucked into the high-speed flow. As a result, the damper chamber is decompressed and hydraulic pressure in the forward direction acts on the needle, so that the valve member can be stably held in the open state until the end of the metering step. Therefore, it is possible to perform metering as intended, and the responsiveness during high-speed rotation is further improved.
Further, as a secondary effect of the damper effect, when the needle collides with the valve member, the needle is decelerated and the collision force against the valve member is alleviated, so that noise due to the collision can be reduced.

  The damper effect and the diaphragm effect can be compatible. However, when the hydraulic assist force to the needle is sufficiently obtained only by the damper effect, the throttle effect may be small. That is, it is not necessary to set the outer diameter of the large diameter portion slightly smaller than the inner diameter of the cylindrical member to form the throttle portion. Therefore, the outer diameter of the large-diameter portion can be set to be relatively small, and a sufficient cross-sectional area can be ensured for flowing the required flow rate.

In the high-pressure pump according to claim 8, in the high-pressure pump according to claim 7, the needle includes a second small-diameter portion that is smaller in diameter than the large-diameter portion and continuous on the upstream side of the large-diameter portion, A brim portion having a predetermined thickness in the axial direction is formed.
Even in the configuration having a damper effect, the large diameter portion does not need to extend to the upstream side, and the needle can be reduced in weight by making the upstream side thin as the second small diameter portion. By reducing the weight of the needle, the operability of the needle by the hydraulic assist force and the electromagnetic attraction force is improved, so that the responsiveness at high speed rotation is further improved.

It is sectional drawing which shows the whole high-pressure pump structure by 1st Embodiment of this invention. It is sectional drawing which shows the suction valve closed state of the high pressure pump by 1st Embodiment of this invention. It is sectional drawing which shows the suction valve open state of the high pressure pump by 1st Embodiment of this invention. (A): It is explanatory drawing which shows the flow of the fuel of the suction process in the high pressure pump of 1st Embodiment of this invention. (B): It is explanatory drawing which shows the flow of the fuel of the metering process in the high pressure pump of 1st Embodiment of this invention. It is a characteristic view at the time of high speed rotation of the high pressure pump of a 1st embodiment of the present invention. It is sectional drawing which shows the high pressure pump by the modification of 1st Embodiment of this invention. It is sectional drawing which shows the suction valve closed state of the high pressure pump by 2nd Embodiment of this invention. (A): It is explanatory drawing which shows the flow of the fuel of the suction process in the high pressure pump of 2nd Embodiment of this invention. (B): It is explanatory drawing which shows the flow of the fuel of the metering process in the high pressure pump of 2nd Embodiment of this invention. (A): It is sectional drawing which shows the suction valve closed state of the high pressure pump by 3rd Embodiment of this invention. (B): It is a Z arrow view of (a). (A): It is explanatory drawing which shows the flow of the fuel of the suction process in the high pressure pump of 3rd Embodiment of this invention. (B): It is explanatory drawing which shows the flow of the fuel of the metering process in the high pressure pump of 3rd Embodiment of this invention. It is sectional drawing which shows the suction valve closed state of the high pressure pump by 4th Embodiment of this invention. (A): It is sectional drawing which shows a suction process among the suction valve open states of the high pressure pump by 4th Embodiment of this invention. (B): It is sectional drawing which shows a metering process among the suction valve open states of the high pressure pump by 4th Embodiment of this invention. It is sectional drawing which shows the suction valve closed state of the high pressure pump by 5th Embodiment of this invention. (A): It is explanatory drawing which shows the behavior of the needle at the time of valve opening in the high pressure pump of 5th Embodiment of this invention. (B): It is explanatory drawing which shows the behavior of the needle at the time of valve opening in the high pressure pump of 5th Embodiment of this invention. (A): It is sectional drawing which shows the suction valve closed state of the high pressure pump by 6th Embodiment of this invention. (B): It is a principal part enlarged view of (a). (A): It is sectional drawing which shows the suction valve open state of the high pressure pump by 6th Embodiment of this invention. (B): It is a principal part enlarged view of (a). It is a characteristic view at the time of high speed rotation of the high pressure pump of a prior art. It is sectional drawing which shows the suction valve open state of the high pressure pump of a prior art.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
First, the configuration of the high-pressure pump 10 will be described with reference to FIG. 1, and the details of the suction valve portion and the electromagnetic actuator portion will be described with reference to FIG.
As shown in FIG. 1, the high-pressure pump 10 includes a plunger portion 80, a discharge valve portion 70, a suction valve portion 20, an electromagnetic actuator 50, and the like.

The outer shell of the high-pressure pump 10 is constituted by a housing 11. A cover 12 is attached to the housing 11 in the upward direction of FIG. 1, and a fuel chamber 90 is formed by the cover 12 and the housing 11. The fuel chamber 90 is provided with a pulsation damper 19 for attenuating fuel pulsation.
A plunger portion 80 is provided on the opposite side of the cover 12. A pressurizing chamber 95 capable of pressurizing the fuel is formed near the middle between the plunger portion 80 and the fuel chamber 90.
Fuel is supplied to the fuel chamber 90 from a fuel tank (not shown). The fuel supplied to the fuel chamber 90 is pumped from the discharge valve portion 70 to a fuel rail (not shown) via the suction valve portion 20 and the pressurizing chamber 95.

Next, the structure of the plunger part 80, the discharge valve part 70, the suction valve part 20, and the electromagnetic actuator 50 will be described in order.
The plunger portion 80 includes a plunger 13, a plunger seal portion 82, a spring seat 83, a plunger spring 84, and the like.

The plunger 13 is supported by a cylinder 14 formed inside the housing 11 and reciprocates in the axial direction. The plunger 13 includes a large-diameter portion 131 having an outer diameter that fits the inner diameter of the cylinder 14 on the pressurizing chamber 95 side, and a small-diameter portion 132 having a smaller outer diameter than the large-diameter portion 131 on the opposite side of the pressurizing chamber 95. Is provided. The large diameter part 131 and the small diameter part 132 are integrated.
A variable volume chamber 17 surrounded by the inner diameter of the cylinder 14 is formed around the small diameter portion 132. The variable volume chamber 17 communicates with the fuel chamber 90 via the volume chamber passage 18. The variable volume chamber 17 supplies fuel to the fuel chamber 90 or is supplied with fuel from the fuel chamber 90 so as to compensate for a part of the change in the volume of the pressurizing chamber 95.

The plunger seal portion 82 is disposed at the end of the cylinder 14. Specifically, it is composed of a seal member, an oil seal holder, an oil seal, and the like, and the fuel and oil around the plunger 13 are sealed.
A spring seat 83 is disposed at the end of the plunger 13. The spring seat 83 reciprocates in the axial direction via a tappet or a roller lifter (not shown) by rotation of a camshaft (not shown).

One end of the plunger spring 84 abuts on the upper surface of the spring seat 83, and the other end abuts on the concave surface of the oil seal holder inserted into the housing 11. The plunger spring 84 functions as a return spring of the plunger 13 and urges the spring seat 83 to contact the tappet and also urges the tappet to contact the cam surface.
With such a configuration of the plunger portion 80, the reciprocating movement of the plunger 13 according to the rotation of the camshaft is realized, and the volume change of the pressurizing chamber 95 is created.

  Next, the discharge valve portion 70 has a cylindrical accommodating portion 71 formed by the housing 11. A discharge valve 72, a spring 73, and a locking portion 74 are accommodated in a storage chamber 711 formed by the storage portion 71. Further, the opening portion of the storage chamber 711 is a discharge port 75. A valve seat 712 is formed in a deep portion of the storage chamber 711 on the opposite side to the discharge port 75.

  The discharge valve 72 abuts on the valve seat 712 and closes by the biasing force of the spring 73 and the force generated by the pressure in the fuel rail. Thereby, the discharge valve 72 stops the fuel discharge when the pressure of the fuel in the pressurizing chamber 95 is low. On the other hand, when the force due to the fuel pressure in the pressurizing chamber 95 is larger than the sum of the biasing force of the spring 73 and the pressure in the fuel rail, the discharge valve 72 is opened, and the fuel is discharged from the pressurizing chamber 95 to the discharge passage 96. And discharged from the discharge port 75.

Next, the suction valve section 20 includes a valve member 21, a valve spring 22, a valve outer body 23, a valve inner body 24, a leaf spring 25, and a locking member 26, and is pressurized from the upstream chamber 92 on the downstream side. Open and close the passage to the chamber 95.
The valve outer body 23 has a hollow cylindrical shape and is disposed between the upstream chamber 92 and the pressurizing chamber 95 of the housing 11. In the valve outer body 23, the end portion on the pressurizing chamber 95 side is urged by the leaf spring 25, and the end portion on the upstream chamber 92 side is locked and fixed to the locking member 26.
A valve cylinder portion 232 is provided near the upstream chamber 92 of the valve outer body 23, and the valve cylinder portion 232 has an upstream passage 93 radially inward within the axial thickness range. The valve cylinder portion 232 embodies the “cylinder member” recited in the claims.
The valve outer body 23 has a valve chamber 941 on the downstream side of the upstream passage 93. An annular seat portion 231 is provided on the downstream side of the valve cylinder portion 232 so as to face the valve chamber 941.

The valve inner body 24 is assembled integrally with the valve outer body 23 on the radially inner side of the valve outer body 23. The valve inner body 24 has a passage 942 that connects the valve chamber 941 and the suction passage 94 connected to the pressurizing chamber 95.
The valve member 21 is slidably supported on the outer peripheral portion 241 of the valve inner body 24 and is disposed in the valve chamber 941. A pressure receiving surface 211 is formed on the upstream side of the valve member 21, and an annular portion of the pressure receiving surface 211 on the outer side in the radial direction can be seated on the seat portion 231. The pressure receiving surface 211 embodies the “upstream end surface” recited in the claims.

The valve spring 22 is disposed in a spring accommodating chamber 242 provided in the valve inner body 24. The valve spring 22 biases the valve member 21 to be seated on the seat portion 231.
The spring accommodating chamber 242 communicates with the passage 942 through the communication hole 243, and the spring accommodating chamber 242 and the valve chamber 941 are maintained at the same pressure when the valve member 21 slides.

  An end surface 602 of a needle 61 (described later) can come into contact with the center of the pressure receiving surface 211 of the valve member 21. Here, the load of the valve spring 22 that biases the valve member 21 toward the seat portion 231 is larger than the load of the needle spring 56 that biases the needle 61 toward the valve member 21. As a result, when the electromagnetic actuator 50 described later is not in operation, the valve member 21 is seated on the seat portion 231 and is closed, and the passage between the upstream chamber 92 and the pressurizing chamber 95 is blocked. That is, a normally closed type high-pressure pump is configured.

Next, the electromagnetic actuator 50 includes a coil 51, a first stator 52, a movable core 53, a second stator 54, a flange 55, a needle spring 56, a needle 61, a needle stopper 571, a spool 58, and a spacer 59. .
The coil 51 is wound around a spool 58 made of resin, and generates a magnetic field when energized.

  The first stator 52, the second stator 54, and the flange 55, which is the third stator, are made of a magnetic material. A flange 55 that is a third stator is attached to the cylindrical portion 15 of the housing body 11. The first stator 52 is disposed on the radially inner side of the coil 51 on the opposite side of the flange 55 from the housing 11. A spacer 59 made of a nonmagnetic material is interposed between the flange 55 and the first stator 52 to prevent a magnetic short circuit between the flange 55 and the first stator 52. The second stator 54 is disposed so as to cover the radially outer side of the coil 51, and magnetically connects the flange 55 and the first stator 52.

The movable core 53 is formed in a cylindrical shape from a magnetic material. The movable core 53 is accommodated between the flange 55 and the first stator 52 in the axial direction and radially inward of the first stator 52 and the spacer 59 in the radial direction so as to be reciprocally movable in the axial direction. Here, since the arrangement of the movable core 53 in the axial direction is closer to the flange 55 than the first stator 52, when the coil 51 is energized, the movable core 53 is attracted to the flange 55, which is the third stator. Move.
The movable core 53 has a communication hole 531 penetrating in the axial direction. Thereby, during the reciprocating movement, the front and rear of the movable core 53 in the axial direction are maintained at the same pressure.

  The needle 61 is assembled integrally with the movable core 53 and reciprocates in the axial direction together with the movable core 53. The first stator 52 is provided with a needle stopper 571 that faces one end of the needle 61 and restricts the backward limit of the needle 61. A needle spring 56 is provided between the needle stopper 571 and the needle 61. The needle spring 56 biases the needle 61 toward the flange 55, that is, in the forward direction.

The needle 61 passes through the flange 55 and extends into the housing 11. An end surface 602 which is the other end portion of the needle 61 is in contact with the pressure receiving surface 211 of the valve member 21 by the urging force of the needle spring 56. However, since the load of the valve spring 22 is stronger than the load of the needle spring 56 as described above, the valve member 21 does not move due to the urging force of the needle spring 56.
Further, when the coil 51 is energized, the movable core 53 is attracted by the flange 55, so that the needle 61 advances in a direction to open the valve member 21 against the urging force of the valve spring 22.

Next, the main part of the present invention will be described with reference to FIGS.
The needle 61 has a shaft end portion 601 on the tip side that can come into contact with the valve member 21, and a shaft portion 603 on the electromagnetic actuator 50 side. The shaft end portion 601 and the shaft portion 603 have substantially the same diameter. The shaft end portion 601 embodies the “first small diameter portion” recited in the claims, and the shaft portion 603 embodies the “second small diameter portion” recited in the claims. .
Between the shaft end portion 601 and the shaft portion 603, a flange portion 611 having a larger diameter than the shaft end portion 601 and the shaft portion 603 is formed. The collar portion 611 is located within the range of the upstream passage 93 when the needle 61 is moving forward and backward. The outer diameter φD1 of the flange portion 611 is set slightly smaller than the inner diameter φD0 of the valve cylinder portion 232.
The outer peripheral surface 612 of the collar portion 611 is substantially parallel to the axis, and the upstream surface 613 and the downstream surface 614 are both substantially perpendicular to the axis. The upstream surface 613 and the downstream surface 614 are substantially parallel.

A throttle channel 931 is formed in the gap between the outer peripheral surface 612 of the flange portion 611 and the inner periphery of the valve cylinder portion 232. The cross-sectional area of the throttle channel 931 is equal to or larger than the cross-sectional area necessary for securing a required flow rate from the upstream chamber 92 to the pressurizing chamber 95. The throttle channel 931 embodies the “squeezing part” described in the claims.
Further, an intermediate chamber 933 is formed between the flange portion 611 and the valve member 21.

(Operation)
Next, the operation of the high-pressure pump 10 will be described. The high-pressure pump 10 operates by the plunger 13 moving up or down in conjunction with the rotation of the camshaft, and repeating the cycle of the suction process, the metering process, and the pressurizing process.

(1) Suction process The plunger 13 descends from the ascending limit, and the pressure chamber 95 is depressurized. The valve member 21 is separated from the seat portion 231 against the urging force of the valve spring 22, and fuel flows from the fuel chamber 90 into the pressurizing chamber 95 through the introduction passage 91 and the upstream chamber 92. Further, the volume of the variable volume chamber 17 decreases as the plunger 13 is lowered, and the fuel in the variable volume chamber 17 is supplied to the fuel chamber 90 through the volume passage 18.

  Further, the energization command of the electromagnetic actuator 50 is turned on, and the needle 61 moves forward. At this time, during high-speed rotation, it takes a relatively long time for the electromagnetic attractive force to reach the maximum value with respect to the process cycle. Therefore, at the initial stage of the inhalation process, an electromagnetic attractive force sufficient to advance the needle 61 cannot be obtained.

Here, the flow of fuel in the upstream passage 93 will be described with reference to FIG.
In the suction process, the fuel flows from the upstream chamber 92 to the valve chamber 941 as indicated by a broken line in FIG. When the fuel flows from the upstream chamber 92 side of the flange portion 611 into the throttle channel 931, the cross-sectional area suddenly decreases, so that the hydraulic pressure Pm of the intermediate chamber 933 on the downstream side of the flange portion 611 is equal to the hydraulic pressure Pu of the upstream chamber 92. Lower than. Therefore, a positive differential pressure ΔPum between the hydraulic pressure Pu and the hydraulic pressure Pm is generated. This generates a hydraulic assist force that pushes the needle 61 in the forward direction.

Due to this “throttle effect”, even when the electromagnetic attractive force cannot be sufficiently obtained during high-speed rotation, the needle 61 can be rapidly advanced, and after the advance, it is stably held at the forward limit.
Further, the fuel flow is also throttled in the seat portion flow path 932 in the gap between the valve member 21 and the seat portion 231, and a positive differential pressure ΔPmv between the hydraulic pressure Pm in the intermediate chamber 933 and the hydraulic pressure Pv in the valve chamber 941 is generated. . Accordingly, the hydraulic pressure acts in a direction to open the valve member 21.
Therefore, the valve member 21 is stably held in the valve open state, that is, the “full lift position” by combining the action of the oil pressure on the needle 61 and the action of the oil pressure on the valve member 21 itself.

(2) Metering step The plunger 13 changes from the lower limit to the upper limit, and the fuel in the pressurizing chamber 95 is returned to the fuel chamber 90 via the upstream chamber 92 and the introduction passage 91. Further, part of the fuel in the fuel chamber 90 is returned to the variable volume chamber 17 through the volume passage 18.
As shown by a broken line in FIG. 4B, the fuel flows from the valve chamber 941 to the upstream chamber 92. Part of the fuel flows directly from the valve chamber 941 to the upstream chamber 92, and the other part once flows to the intermediate chamber 933 and then flows into the throttle channel 931.
At this time, the hydraulic pressure Pv of the valve chamber 941 is relatively high, and the hydraulic pressure Pu of the upstream chamber 92 is relatively low. The hydraulic pressure Pm in the intermediate chamber 933 is in the middle. Therefore, the effect of the differential pressure obtained in the inhalation process is reduced.
On the other hand, at this stage, the electromagnetic attractive force becomes relatively large, the needle 61 is held at the forward limit by the electromagnetic attractive force, and the valve member 21 maintains the valve open state.

(3) Pressurization process The energization command of the electromagnetic actuator 50 is turned off while the plunger 13 is being lifted, and the electromagnetic attractive force is lost. Then, the urging force of the valve spring 22 and the pressure of the fuel returned from the pressurizing chamber 95 act on the valve member 21 in the valve closing direction, and the needle 61 moves backward together with the valve member 21.
When the valve member 21 is closed, the fuel in the pressurizing chamber 95 cannot return to the upstream chamber 92 and is further pressurized. When the pressure in the pressurizing chamber 95 exceeds a predetermined pressure, the discharge valve 72 is opened against the biasing force of the spring 73 of the discharge valve unit 70, and the fuel is discharged to the discharge port 75 via the discharge passage 96. The

(effect)
With reference to FIG. 5 and FIG. 17, the characteristics of the embodiment of the present invention and the prior art during high-speed rotation will be compared.
FIGS. 5A to 5F show characteristics at the time of high-speed rotation of the embodiment of the present invention. At time ta in FIG. 5, the plunger starts to descend from the ascent limit, and the suction process is started. A little later, at time t1, the energization command is turned on, current starts to flow, and gradually increases toward the maximum value. As the current increases, the electromagnetic attractive force also increases.
By depressurizing the pressurizing chamber 95, the valve member 21 is in a full lift state at time t2 prior to the needle 61. At this stage, the electromagnetic attractive force is considerably smaller than the maximum value. However, the needle 61 advances with the operation being assisted by the above-described throttling effect. Therefore, the valve member 21 is slightly delayed and reaches the forward limit at time t <b> 3 and contacts the valve member 21. At this time, since the load of the electromagnetic actuator 50 is suddenly eliminated, the current temporarily decreases. Thereafter, the valve member 21 and the needle 61 are held at the full lift position.

At time tb, the plunger reaches the lowering limit and shifts from the suction process to the metering process. At time t4, the current and the electromagnetic attractive force reach the maximum values, and the force for pushing the needle 61 in the forward direction is sufficient.
At time tc, the energization command is turned off, the current and the electromagnetic attractive force become 0, and the needle 61 starts to retract. When the needle 61 returns to the retracted position at t5, the needle spring 56 absorbs the impact and vibrates, and then stops.

  (D) 'of FIG. 5 is a characteristic at low speed rotation for comparison. During the low-speed rotation, the descending speed of the plunger 13 in the suction process is slow, and the flow rate of the fuel flowing from the upstream chamber 92 to the pressurizing chamber 95 is slow. Therefore, the valve member 21 opens slowly, and the needle 61 moves forward simultaneously following the valve opening of the valve member 21.

FIGS. 17A to 17F show characteristics at the time of high-speed rotation when a normally closed type is configured based on the prior art of Patent Document 1. FIG. The prior art is the same as the present invention from time ta to time t2 in FIG. At this stage, the electromagnetic attractive force is considerably small with respect to the maximum value, and there is no assist due to the throttling effect, so that the advance of the needle is considerably delayed. As a result, the needle does not reach the forward limit even at time tb.
When the plunger reaches the lowering limit at time tb and shifts from the suction process to the metering process, the pressure on the pressurizing chamber side increases and the valve member starts to close. Then, at time t3, the needle in the middle of advancing comes into contact with the valve member in the middle of closing the valve and is pushed back by the valve member, and retreats to the retreat limit at time t5.

  At this time, the valve member closes before time t5 when the energization command is turned off. After the valve is closed, the fuel scheduled to be returned to the upstream chamber is discharged to the discharge port unintentionally. That is, metering as intended is not performed, and the switching timing from the metering process to the pressurizing process is substantially advanced. As a result, excess fuel (shaded area in FIG. 17 (f)) is discharged.

As described above, according to the present invention, the valve opening state can be reliably maintained until the end of the metering process in which the energization command is turned off even during high-speed rotation. Therefore, metering can be performed as intended, and abnormal high pressure due to excessive fuel being discharged from the discharge port 75 can be prevented.
Further, unlike another prior art, the needle and the valve member are not manufactured as an integral structure, so that the manufacturing cost is not increased.

(Modification of the first embodiment)
A modification of the first embodiment of the present invention will be described with reference to FIG. In this modification, the large diameter portion 671 of the needle 67 extends to the electromagnetic actuator 50 side and does not form a brim portion. Also in this modification, the outer diameter φD 7 of the large diameter portion 671 is set slightly smaller than the inner diameter φD 0 of the valve cylinder portion 232, and the throttle flow is between the outer peripheral surface 672 of the large diameter portion 671 and the valve cylinder portion 232. A path 931 is formed.

  Outside the range of the upstream passage 93, even if the large-diameter portion 671 extends or the large-diameter portion 671 continues to the small-diameter shaft portion, there is no relation to the formation of the throttle channel. Accordingly, if the unnecessary portion is cut to form the flange portion, the needle can be reduced in weight, and the operability of the needle is improved. On the other hand, if the large diameter portion is left as it is, the number of processing steps can be reduced, and the manufacturing cost can be reduced.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the configuration excluding the needle 62 is the same as that of the first embodiment.
The needle 62 has a shaft end portion 601 on the distal end side capable of contacting the valve member 21, and a shaft portion 603 on the electromagnetic actuator 50 side. The shaft end portion 601 and the shaft portion 603 have substantially the same diameter.
Between the shaft end portion 601 and the shaft portion 603, a flange portion 621 having a larger diameter than the shaft end portion 601 and the shaft portion 603 is formed. The collar portion 621 is located within the range of the upstream passage 93 when the needle 62 is moving forward and backward. The outer diameter φD2 of the collar portion 621 is set slightly smaller than the inner diameter φD0 of the valve cylinder portion 232.
The outer peripheral surface 622 of the flange 621 is substantially parallel to the axis, and the upstream surface 623 and the downstream surface 624 are both substantially perpendicular to the axis. The upstream surface 623 and the downstream surface 624 are substantially parallel.

  The corners of the outer peripheral surface 622 and the upstream surface 623 are not chamfered. On the other hand, a chamfered portion 626 that is inclined toward the upstream surface 623 at an angle of about 20 to 30 ° from the radially inner side to the radially outer side of the downstream surface 624 is formed at the corner between the outer peripheral surface 622 and the downstream surface 624. Is formed. The corners of the outer peripheral surface 622 and the chamfered portion 626 are rounded. The downstream surface 624 embodies the “downstream surface” recited in the claims.

A throttle channel 931 is formed in the gap between the outer peripheral surface 622 of the collar portion 621 and the inner periphery of the valve cylinder portion 232. The cross-sectional area of the throttle channel 931 is equal to or larger than the cross-sectional area necessary for securing the flow rate from the upstream chamber 92 to the pressurizing chamber 95.
An intermediate chamber 933 is formed between the flange 621 and the valve member 21.

  In the suction process, fuel flows from the upstream chamber 92 to the valve chamber 941 as indicated by a broken line in FIG. When the fuel flows into the throttle channel 931 from the upstream chamber 92 side of the flange portion 621, the cross-sectional area suddenly decreases. Further, there is no chamfered portion on the upstream surface 623 side, and the fuel collides with the upstream surface 623, so that a vortex is easily generated. Therefore, the positive differential pressure ΔPum generated between the upstream chamber 92 and the intermediate chamber 933 is relatively large. This generates a hydraulic assist force that pushes the needle 62 in the forward direction.

Due to this “throttle effect”, even if the electromagnetic attractive force cannot be sufficiently obtained during high-speed rotation, the needle 62 can be rapidly advanced, and after the advance, it is stably held at the forward limit.
Further, the fuel flow is also throttled in the seat portion flow path 932 in the gap between the valve member 21 and the seat portion 231, and a positive differential pressure ΔPmv between the hydraulic pressure Pm in the intermediate chamber 933 and the hydraulic pressure Pv in the valve chamber 941 is generated. . Accordingly, the hydraulic pressure acts in a direction to open the valve member 21.
Therefore, the valve member 21 is stably held in the valve open state, that is, the “full lift position” by combining the action of the oil pressure on the needle 62 and the action of the oil pressure on the valve member 21 itself.

In the metering step, the fuel flows from the valve chamber 941 to the upstream chamber 92 as indicated by a broken line in FIG. Part of the fuel flows directly from the valve chamber 941 into the throttle channel 931, and the other part flows into the intermediate chamber 933 and then into the throttle channel 931. When the fuel flows from the intermediate chamber 933 into the throttle channel 931, the fuel flows along the chamfered portion 626, and the cross-sectional area gradually decreases.
At this time, the negative differential pressure ΔPmu generated between the intermediate chamber 933 and the upstream chamber 92 is relatively small with respect to the positive differential pressure ΔPum. That is, in the metering step, the squeezing effect can be suppressed. Thereby, the force which pushes back the needle 62 in the backward direction becomes relatively small. Therefore, the valve member 21 can be stably held at the full lift position, which is advantageous compared to the first embodiment.

The description of “flow coefficient C” will be supplemented for the operation of the second embodiment.
Even if the cross-sectional area of the throttle channel 931 is the same, there are cases where it is easy to flow and difficult to flow depending on the shape of the inflowing portion. Become. When the flow path cross-sectional area and the flow rate are constant, the flow coefficient C and the square root of the differential pressure ΔP are inversely proportional. Therefore, when the flow coefficient C is large, the differential pressure ΔP decreases, and when the flow coefficient C is small, the differential pressure ΔP increases.

In the above example, in the suction process, it is difficult to flow into the throttle channel 931, and since the flow coefficient C is small, the differential pressure ΔP is increased and the throttle effect is increased. On the other hand, in the metering step, it is easy to flow into the throttle channel 931, and since the flow coefficient C is large, the differential pressure ΔP is reduced and the throttle effect is reduced.
As described above, in the second embodiment, by providing the chamfered portion 626 on the downstream surface 624 side, it is possible to cause a difference in the throttle effect depending on the fuel flow direction.

(Third embodiment)
A third embodiment of the present invention will be described with reference to FIGS. The third embodiment is the same as the first and second embodiments with respect to the configuration excluding the needle 63.
The needle 63 has a shaft end portion 601 on the tip side that can come into contact with the valve member 21, and a shaft portion 603 on the electromagnetic actuator 50 side. The shaft end portion 601 and the shaft portion 603 have substantially the same diameter.
Between the shaft end portion 601 and the shaft portion 603, a flange portion 631 having a diameter larger than that of the shaft end portion 601 and the shaft portion 603 is formed. The collar portion 631 is located within the range of the upstream passage 93 when the needle 63 is moving forward and backward. The outer diameter φD3 of the flange portion 631 is set slightly smaller than the inner diameter φD0 of the valve cylinder portion 232.
The outer peripheral surface 632 of the collar portion 631 is substantially parallel to the axis, and the upstream surface 633 and the downstream surface 634 are both substantially perpendicular to the axis. The upstream surface 633 and the downstream surface 634 are substantially parallel. The corners of the outer peripheral surface 632 and the upstream surface 633 and the corners of the outer peripheral surface 632 and the downstream surface 634 are not chamfered.

  In the flange portion 631, four orifices 635 are penetrated at positions that divide the circumferential direction into four equal parts. The orifice 635 is a small diameter hole. The mouth on the upstream surface 633 side of the orifice 635 is not chamfered. On the other hand, a tapered portion 636 of about 45 ° is formed at the mouth of the orifice 635 on the downstream surface 634 side. The downstream surface 634 embodies the “downstream surface” recited in the claims.

In the third embodiment, not only the gap between the outer peripheral surface 632 of the flange portion 631 and the inner periphery of the valve cylinder portion 232, but also the throttle passage 931 is formed by four orifices 635.
An intermediate chamber 933 is formed between the flange 621 and the valve member 21.

Here, the fuel passing through the orifice 635 will be described.
In the suction process, as shown by a broken line in FIG. 10A, the fuel flows from the upstream chamber 92 to the valve chamber 941 through the intermediate chamber 933. When the fuel flows into the orifice 635 from the upstream chamber 92 side of the flange portion 631, the cross-sectional area suddenly decreases. In addition, there is no chamfered portion on the upstream surface 633 side of the orifice 635, and fuel collides with the upstream surface 633, and eddy currents are easily generated. Therefore, the positive differential pressure ΔPum generated between the upstream chamber 92 and the intermediate chamber 933 is relatively large. This generates a hydraulic assist force that pushes the needle 63 in the forward direction.

Due to this “throttle effect”, even if the electromagnetic attractive force cannot be sufficiently obtained during high-speed rotation, the needle 63 can move forward quickly and be stably held at the forward limit after moving forward.
Further, the fuel flow is also throttled in the seat portion flow path 932 in the gap between the valve member 21 and the seat portion 231, and a positive differential pressure ΔPmv between the hydraulic pressure Pm in the intermediate chamber 933 and the hydraulic pressure Pv in the valve chamber 941 is generated. . Accordingly, the hydraulic pressure acts in a direction to open the valve member 21.
Therefore, the valve member 21 is stably held in the valve open state, that is, the “full lift position” by combining the action of the oil pressure on the needle 63 and the action of the oil pressure on the valve member 21 itself.

In the metering step, the fuel flows from the valve chamber 941 through the intermediate chamber 933 to the orifice 635 as indicated by a broken line in FIG. When the fuel flows into the orifice 635 from the intermediate chamber 933, the fuel flows along the tapered portion 636, and the cross-sectional area gradually decreases, so that the fuel flows easily.
At this time, the negative differential pressure ΔPmu generated between the intermediate chamber 933 and the upstream chamber 92 is relatively small with respect to the positive differential pressure ΔPum. That is, in the metering step, the squeezing effect can be suppressed. Thereby, the force which pushes back the needle 62 in the backward direction becomes relatively small. Therefore, similarly to the second embodiment, the valve member 21 can be stably held at the full lift position.

  Further, when the throttle channel is formed in the gap between the flange portion and the cylindrical member, the cross-sectional area of the gap is likely to vary, and it is relatively difficult to set the dimensions to secure the cross-sectional area necessary for flowing the required flow rate. Therefore, in the third embodiment, the necessary cross-sectional area can be easily ensured by providing the orifice 635 that penetrates the flange 631.

(Fourth embodiment)
A fourth embodiment of the present invention will be described with reference to FIGS. In the fourth embodiment, the configuration excluding the needle 64, the movable plate 68, and the plate spring 647 is the same as that in the first to third embodiments.
In the fourth embodiment, an annular movable plate 68 is slidably provided on the radially outer side of the shaft portion 603 of the needle 64. A restricting portion 641 having a diameter larger than that of the shaft portion 603 and smaller than that of the movable plate 68 is provided at the distal end portion of the needle 64. The restricting portion 641 restricts the advance limit of the movable plate 68.

The movable plate 68 has an annular flat plate shape and is located within the range of the upstream passage 93 when the needle 64 is advanced and retracted. The outer diameter φD4 of the movable plate 68 is set slightly smaller than the inner diameter φD0 of the valve cylinder portion 232.
In a state where the needle 64 is inserted into the shaft portion 603, the outer peripheral surface 682 of the movable plate 68 is substantially parallel to the shaft, and the upstream surface 683 and the downstream surface 684 are both substantially perpendicular to the shaft. The upstream surface 683 and the downstream surface 684 are substantially parallel.
In the fourth embodiment, the restricting portion 641 embodies the “first small diameter portion” recited in the claims.

A plate spring 647 is installed between the upstream surface 683 of the movable plate 68 and the flange 55. The plate spring 647 biases the movable plate 68 toward the tip of the needle 64. As a result, the downstream surface 684 of the movable plate 68 comes into contact with the restricting portion 641 of the needle 64. At this time, as shown in FIGS. 11 and 12A, the movable plate 68 is positioned within the range of the upstream passage 93 when the needle 64 is retracted and advanced.
The load of the plate spring 647 is sufficiently weaker than the load of the needle spring 56 and the load of the valve spring 22. Therefore, the load of the plate spring 647 does not affect the operation of the needle 64 itself and the opening / closing of the valve member 21.

A throttle channel 931 is formed in the gap between the outer peripheral surface 682 of the movable plate 68 and the inner periphery of the valve cylinder portion 232. The cross-sectional area of the throttle channel 931 is equal to or larger than the cross-sectional area necessary for securing the flow rate from the upstream chamber 92 to the pressurizing chamber 95.
An intermediate chamber 933 is formed between the movable plate 68 and the valve member 21.

  In the suction process, fuel flows from the upstream chamber 92 to the valve chamber 941 as indicated by a broken line in FIG. At this time, the upstream surface 683 of the movable plate 68 becomes a pressure receiving surface, and the movable plate 68 pushes the restricting portion 641 of the needle 64 in the forward direction. Moreover, the force which pushes the movable plate 58 to a forward direction acts by the aperture_diaphragm | restriction effect similar to 1st-3rd embodiment.

As a result, even when the electromagnetic attractive force cannot be sufficiently obtained during high-speed rotation, the needle 64 can be rapidly advanced and is stably held at the forward limit after the advance.
Further, as in the first to third embodiments, the hydraulic pressure acts on the valve opening side with respect to the valve member 21 by the throttling effect in the seat portion flow path 932.
Therefore, the valve member 21 is stably held in the valve open state, that is, the “full lift position” by combining the action of the oil pressure on the needle 64 and the action of the oil pressure on the valve member 21 itself.

In the metering step, the fuel flows from the valve chamber 941 to the upstream chamber 92 as indicated by a broken line in FIG. At this time, the downstream surface 684 of the movable plate 68 becomes a pressure receiving surface, the movable plate 68 slides toward the flange 55 against the urging force of the plate spring 647, and exceeds the range of the upstream passage 93 to enter the upstream chamber 92. Move to.
Then, the area of the flow path from the valve chamber 941 to the upstream chamber 92 increases, and a negative differential pressure does not occur between the upstream surface 683 and the downstream surface 684 of the movable plate 68.
Thereby, the force which pushes the needle 64 back in the backward direction becomes relatively small. Therefore, the valve member 21 can be stably held at the full lift position.

(Fifth embodiment)
A fifth embodiment of the present invention will be described with reference to FIGS. In the fifth embodiment, the configuration excluding the needle 65 is the same as that in the first to fourth embodiments.
In the needle 65 of the fifth embodiment, the gap distance H0 between the downstream surface 654 of the collar 651 and the end surface 602 of the needle 65 is set to a minute distance of, for example, 0.1 mm or less.
Further, a very small space between the flange 651 and the valve member 21 is referred to as a “damper chamber 934” in distinction from the “intermediate chamber 933” in the first to fourth embodiments. The “damper chamber 934” is configured to exhibit a “damper effect” described later.

The operation of the fifth embodiment will be described.
In the initial stage of the suction process, the pressure chamber 95 is depressurized by the lowering of the plunger 13, so that a positive differential pressure is generated between the upstream chamber 92 side and the valve chamber 941 side of the valve member 21. On the other hand, since the rise of the electromagnetic attractive force of the electromagnetic actuator 50 is delayed at high speed rotation, the valve member 21 is opened before the operation of the needle 65 as shown in FIG.

  At this time, the gap distance H0 when the valve is closed rapidly changes to the gap distance H when the valve is opened, and the volume of the damper chamber 934 is rapidly expanded. The smaller the gap distance H0 with respect to the gap distance H, the larger the volume change rate. Since this volume change is rapid, the fuel cannot instantaneously flow into the expanded damper chamber 934, and the damper chamber 934 is in a decompressed state. Therefore, a differential pressure is generated between the upstream side and the downstream side of the flange 651, and an oil pressure acts on the needle 65 in the forward direction (left direction in FIG. 14A). Therefore, even when the electromagnetic attractive force is not sufficiently obtained, the needle 65 can advance in response to the energization command.

Further, in the suction process after the valve is opened, the fuel flows from the upstream chamber 92 to the valve chamber 941 at a high speed as indicated by the broken line arrow in FIG. 14B, and therefore, the damper chamber 934 is caused by the Venturi effect based on Bernoulli's theorem. The fuel is sucked out toward the high-speed flow. Furthermore, in the metering step, the fuel flows at a high speed in the direction opposite to the broken arrow in FIG. 14B, and the fuel in the damper chamber 934 is sucked out toward the high-speed flow by the venturi effect as in the suction step. As a result, the damper chamber 934 is depressurized, and hydraulic pressure in the forward direction acts on the needle 65, so that the valve member 21 can be stably held at the valve open position even when the electromagnetic attractive force is not sufficiently obtained. can do. Therefore, metering as intended is possible.
As described above, in the fifth embodiment, the responsiveness during high-speed rotation is improved by the “damper effect”.

  Further, as a secondary effect of the damper effect, when the needle 65 collides with the valve member 21, the needle 65 is decelerated and the collision force against the valve member 21 is alleviated, so that noise due to the collision can be reduced. .

  The damper effect and the diaphragm effect can be compatible. However, when the hydraulic assist force to the needle 65 is sufficiently obtained only by the damper effect, the throttle effect may be small. That is, it is not necessary to set the outer diameter φD5 of the flange portion 651 slightly smaller than the inner diameter φD0 of the valve cylinder portion 232 to form the throttle channel. Therefore, the outer diameter φD5 of the brim portion 651 can be set to be relatively small, and a sufficient cross-sectional area for flowing a required flow rate can be ensured.

(Sixth embodiment)
A sixth embodiment of the present invention will be described with reference to FIGS. The sixth embodiment is substantially the same as the first to fifth embodiments except for the needle 66.
The needle 66 of the sixth embodiment is similar to the modification of the first embodiment in that the large diameter portion 661 extends to the electromagnetic actuator 50 side. Further, the clearance distance H0 between the downstream surface 664 of the large diameter portion 661 and the tip of the needle 66 is similar to the fifth embodiment in that it is set to a minute distance of 0.1 mm or less, for example.
A spherical portion 668 is provided at the tip of the needle 66, and as shown in FIG. 15, the apex of the spherical portion 668 abuts against the pressure receiving surface 211 of the valve member 21 when the valve is closed.

  The operation and effect of the sixth embodiment are substantially the same as those of the fifth embodiment, and a hydraulic assist force in the forward direction is generated with respect to the needle 66 by the damper effect. Thereby, the responsiveness at the time of high speed rotation improves. Furthermore, noise when the needle 65 collides with the valve member 21 can be reduced. In addition, when a sufficient hydraulic assist force can be obtained only by the damper effect, it is not necessary to form a throttle channel between the outer peripheral surface 662 of the large diameter portion 661 and the valve cylinder portion 232. Therefore, the outer diameter φD6 of the large-diameter portion can be set to be relatively small, and a sufficient cross-sectional area can be ensured for flowing the required flow rate.

Note that the needle 66 is heavier than the first to fifth embodiments, and the shaft tends to swing. When the tip is formed in a plane perpendicular to the shaft like the end surface 602 of the first to fifth embodiments, when the shaft swings, the corner of the end surface 602 hits the pressure receiving surface 211 of the valve member 21 and the valve member There is a possibility that the valve opening operation 21 may be inclined or the pressure receiving surface 211 may be damaged.
Therefore, in the sixth embodiment, by providing the spherical surface portion 668 at the tip, even if the shaft is swung and comes into contact with the pressure receiving surface 211 of the valve member 21, there is no adverse effect.

  As mentioned above, this invention is not limited to such embodiment, In the range which does not deviate from the meaning of invention, it can implement with a various form.

10: high pressure pump, 11: housing, 13: plunger, 14: cylinder,
20: intake valve portion, 21: valve member, 211: pressure receiving surface (upstream end surface), 22: valve spring,
23: valve outer body, 231: seat part, 232: valve cylinder part (cylinder member),
24: Valve inner body,
50: Electromagnetic actuator, 51: Coil, 52: First stator, 53: Movable core,
54: second stator, 55: flange (third stator), 56: needle spring,
571: Needle stopper,
601: Shaft end (first small diameter portion), 602: End face, 603: Shaft portion (second small diameter portion),
61, 62, 63, 64, 65, 66, 67: needle,
611, 621, 631, 651: brim portion (large diameter portion),
612, 622, 632, 652, 662, 672, 682: outer peripheral surface,
613, 623, 633, 653, 683: upstream surface,
614, 624, 634, 654, 664, 684: downstream surface (downstream surface),
626, chamfered portion, 635: orifice, 636: tapered portion,
641: restriction part, 647: plate spring, 68: movable plate,
661, 671: large diameter portion, 668: spherical portion,
70: Discharge valve part, 72: Discharge valve, 75: Discharge port, 80: Plunger part,
90: fuel chamber, 91: introduction passage, 92: upstream chamber, 93: upstream passage,
931: Throttle channel (throttle part), 932: Seat part channel, 933: Intermediate chamber, 934: Damper chamber, 941: Valve chamber, 942: Passage, 94: Suction passage, 95: Pressurization chamber, 96: Discharge aisle

Claims (8)

A reciprocating plunger; and
A pressurizing chamber capable of pressurizing fuel by changing its volume by movement of the plunger, and a housing having an upstream chamber provided on the upstream side of the pressurizing chamber;
A cylindrical member provided in the housing and having an upstream passage for introducing fuel from the upstream chamber to the pressurizing chamber;
An annular sheet portion provided on the upstream side of the pressurizing chamber and on the downstream side of the cylindrical member;
A valve member that blocks or communicates with the upstream passage by being seated or separated from the seat portion;
A first small-diameter portion disposed upstream of the valve member and capable of contacting the upstream end surface of the valve member; and the first small-diameter portion having a diameter larger than the first small-diameter portion and within the range of the upstream passage. A needle having a large-diameter portion continuous on the upstream side of
A needle spring that urges the first small diameter portion to abut against the upstream end surface of the valve member;
An electromagnetic actuator that is connected to an end of the needle opposite to the first small-diameter portion and that generates an electromagnetic attractive force so as to move the needle in a valve-opening direction during operation;
A set spring larger than the needle spring, and a valve spring that urges the valve member in a valve closing direction when the electromagnetic actuator is not operated;
In the upstream passage, a throttle portion that reduces the cross-sectional area from the upstream side to the downstream side;
A high pressure pump comprising:   The needle includes a second small-diameter portion that is smaller in diameter than the large-diameter portion and continues to the upstream side of the large-diameter portion, and the large-diameter portion constitutes a flange portion having a predetermined thickness in the axial direction. The high-pressure pump according to claim 1.   The high pressure pump according to claim 2, wherein the brim portion includes a chamfered portion that is inclined from the radially inner side to the outer peripheral surface of the downstream surface toward the upstream side.   The high pressure pump according to claim 2 or 3, wherein the flange portion has an orifice that communicates the upstream side and the downstream side.   The high pressure pump according to claim 4, wherein the flange portion has a tapered portion that extends toward the opening side at the downstream side opening of the orifice. A reciprocating plunger; and
A pressurizing chamber capable of pressurizing fuel by changing its volume by movement of the plunger, and a housing having an upstream chamber provided on the upstream side of the pressurizing chamber;
A cylindrical member provided in the housing and having an upstream passage for introducing fuel from the upstream chamber to the pressurizing chamber;
An annular sheet portion provided on the upstream side of the pressurizing chamber and on the downstream side of the cylindrical member;
A valve member that blocks or communicates with the upstream passage by being seated or separated from the seat portion;
A first small-diameter portion disposed upstream of the valve member and capable of contacting the upstream end surface of the valve member; and having a diameter smaller than the first small-diameter portion and within the range of the upstream passage, A needle comprising a second small diameter portion continuous on the upstream side;
A movable plate disposed so as to be slidable radially outward of the second small diameter portion and to be restricted from sliding by the first small diameter portion;
A needle spring that urges the first small diameter portion to abut against the upstream end surface of the valve member;
An electromagnetic actuator that is connected to an end of the needle opposite to the first small-diameter portion and that generates an electromagnetic attractive force so as to move the needle in a valve-opening direction during operation;
A set spring larger than the needle spring, and a valve spring that urges the valve member in a valve closing direction when the electromagnetic actuator is not operated;
A plate spring that has a smaller set load than the needle spring and biases the movable plate toward the first small-diameter portion; and
In the upstream passage, a throttle portion that reduces the cross-sectional area from the upstream side to the downstream side;
With
When the fuel flows from the upstream chamber to the pressurizing chamber, the movable plate abuts on the first small diameter portion by the urging force of the plate spring,
When the fuel flows from the pressurizing chamber to the upstream chamber, the movable plate slides toward the upstream chamber against the urging force of the plate spring by the pressure of the fuel. A reciprocating plunger; and
A pressurizing chamber capable of pressurizing fuel by changing its volume by movement of the plunger, and a housing having an upstream chamber provided on the upstream side of the pressurizing chamber;
A cylindrical member provided in the housing and having an upstream passage for introducing fuel from the upstream chamber to the pressurizing chamber;
An annular sheet portion provided on the upstream side of the pressurizing chamber and on the downstream side of the cylindrical member;
A valve member that blocks or communicates with the upstream passage by being seated or separated from the seat portion;
A first small-diameter portion disposed upstream of the valve member and capable of contacting the upstream end surface of the valve member; and the first small-diameter portion having a diameter larger than the first small-diameter portion and within the range of the upstream passage. A needle having a large-diameter portion continuous on the upstream side of
A needle spring that urges the first small diameter portion to abut against the upstream end surface of the valve member;
An electromagnetic actuator that is connected to an end of the needle opposite to the first small-diameter portion and that generates an electromagnetic attractive force so as to move the needle in a valve-opening direction during operation;
A set spring larger than the needle spring, and a valve spring that urges the valve member in a valve closing direction when the electromagnetic actuator is not operated;
With
The surface on the downstream side of the large-diameter portion is formed in a gap with the upstream end surface of the valve member so as to form a damper chamber in which the volume rapidly expands when the valve member is opened at high speed. A high-pressure pump, wherein the high-pressure pump is provided close to an upstream end face of the valve member.   The needle includes a second small-diameter portion that is smaller in diameter than the large-diameter portion and continues to the upstream side of the large-diameter portion, and the large-diameter portion constitutes a flange portion having a predetermined thickness in the axial direction. The high-pressure pump according to claim 7.

Images