JP2015094277A - High pressure pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high pressure pump capable of preventing occurrence of vapor lock due to inflow of a fuel of high temperature in a sub-fuel chamber into a main fuel chamber.SOLUTION: A check valve member 301 is held between a driving-side end face 101 of a pump body 10 and a bottom surface of a flange portion of an upper seat 45. When pressure difference obtained by subtracting a pressure of a communication passage 14 from a pressure of the sub-fuel chamber 13 is a prescribed pressure or more, a lead valve portion 35 is brought into a valve close state. The fuel of high temperature in the sub-fuel chamber 13, of which a temperature is increased by heat generation of the fuel leaking through a sliding clearance between a cylinder 20 and a plunger 41 and heat transferred from an engine side, is discharged to the external through a discharge passage 15. Thus vapor lock caused by inflow of the fuel of high temperature in the sub-fuel chamber 13 into the main fuel chamber 12 through the communication passage 14 can be prevented. When the lead valve portion 35 is opened, a fuel of low temperature in the main fuel chamber 12 flows into the sub-fuel chamber 13 through the communication passage 14. The fuel of the sub-fuel chamber 13 is cooled by the inflow of the fuel of low temperature.

Description

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

In recent years, direct-injection engines with good fuel efficiency have attracted attention from the viewpoint of resource saving. In a direct injection engine, it is necessary to inject high-pressure fuel from an injector. Conventionally, there is known a high-pressure pump that sucks in fuel supplied from a low-pressure pump installed in a fuel tank by reciprocating a plunger on the inner wall surface of a cylinder, pressurizes it in a pressurizing chamber, and pumps it to the injector side. Yes.
In this type of high-pressure pump, the fuel leaking from the pressurizing chamber to the non-pressurizing chamber via the sliding gap between the cylinder and the plunger is heated due to heat generation. In general, the part of the plunger on the side opposite to the pressure chamber is disposed near the engine, and heat from the engine is easily transmitted.

  For example, in the high-pressure pump disclosed in Patent Document 1, the fuel in the variable volume chamber formed on the side opposite to the pressurizing chamber of the plunger is likely to become high temperature due to the heat generated from the leak fuel or the heat from the engine. Therefore, the high-pressure pump disclosed in Patent Document 1 forms two communication passages that connect the low-pressure fuel chamber and the variable volume chamber, and one communication passage allows the flow of fuel from the low-pressure fuel chamber to the variable volume chamber. A check valve is provided, and a check valve that allows the flow of fuel from the variable volume chamber to the low pressure fuel chamber is provided in the other communication passage. Thereby, the fuel circulates only in one direction due to the volume change of the variable volume chamber accompanying the reciprocating movement of the plunger.

JP 2012-127290 A

  In the high-pressure pump of Patent Document 1, the low-temperature fuel in the low-pressure fuel chamber is caused to flow into the variable volume chamber by circulating the fuel between the low-pressure fuel chamber and the variable volume chamber, thereby reducing the fuel temperature in the variable volume chamber. . However, in this configuration, the high-temperature fuel in the variable volume chamber moves to the low-pressure fuel chamber and spreads heat throughout the high-pressure pump, so that the average temperature of the fuel gradually increases. As a result, vapor lock may occur in the low pressure fuel chamber.

  Regarding the name of the part, in Patent Document 1, the volume is changed by the reciprocating movement of the plunger on the premise that the plunger has a stepped shape having a large diameter portion and a small diameter portion. Is called “variable volume chamber”. On the other hand, in this specification, the case where a plunger is a shape of a single diameter is assumed, and the term variable volume chamber is not used. Instead, a space corresponding to the “low pressure fuel chamber” in Patent Document 1 is referred to as a “main fuel chamber”, and a space formed on the opposite side of the plunger with respect to the main fuel chamber is referred to as a “sub fuel chamber”.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a high-pressure pump that prevents the occurrence of vapor lock due to the high-temperature fuel in the auxiliary fuel chamber flowing into the main fuel chamber.

The high-pressure pump of the present invention includes a plunger, a cylinder, a pump body, a bottom cover member, and a check valve member.
The cylinder slidably accommodates the plunger and forms a pressurizing chamber that faces a pressurizing end that is one end of the plunger and in which fuel is pressurized. Further, an auxiliary fuel chamber is formed which faces the end of the cylinder opposite to the pressurizing chamber and accumulates fuel leaked from the pressurizing chamber via a sliding gap between the cylinder and the plunger.
The pump body is open to a main fuel chamber to which fuel is supplied from a fuel inlet on the upstream side of the fuel flow from the pressurizing chamber, a driving side end surface opposite to the pressurizing chamber in the axial direction, and a main fuel chamber. A communication passage that communicates with the auxiliary fuel chamber, and a discharge passage that opens to the driving side end surface and accumulates in the auxiliary fuel chamber are discharged to the outside.

The bottom cover member is fixed to the pump body so that the bottom surface faces the drive side end surface.
The check valve member is sandwiched between the drive side end surface of the pump body and the bottom surface of the bottom cover member. The check valve member has a reed valve portion that can close the opening of the communication passage, and allows the flow of fuel from the main fuel chamber to the sub fuel chamber in the communication passage by opening and closing the reed valve portion. Regulates the flow of fuel from the chamber to the main fuel chamber.

In the present invention, the high-temperature fuel in the auxiliary fuel chamber that has risen in temperature due to heat generated by the decompression of leaked fuel or heat transmitted from the engine side is discharged from the discharge passage without flowing into the main fuel chamber by the action of the check valve member. Discharge outside. Therefore, it is possible to prevent the vapor lock from occurring in the main fuel chamber.
In particular, when the plunger has a stepped configuration, when the plunger is raised, the reed valve portion of the check valve member opens, and low temperature fuel flows from the main fuel chamber to the sub fuel chamber. On the other hand, since the reed valve portion is closed when the plunger is lowered, the high temperature fuel in the auxiliary fuel chamber is discharged to the discharge passage. In other words, a pumping action of sending fuel from the main fuel chamber to the discharge passage through the sub fuel chamber is performed by the reciprocating movement of the plunger.

Here, the check valve member has a first plate on which the reed valve portion is formed, and a position corresponding to the reed valve portion is cut out, and a first lift that defines the maximum lift amount of the reed valve portion according to the plate thickness. The two plates are preferably overlapped. Since the check valve member having this configuration can be manufactured by press molding, the manufacturing cost of the parts can be reduced.
Moreover, it is preferable that the check valve member is provided with a positioning protrusion that protrudes toward the driving side end face and is inserted into the receiving recess to position the pump body in the rotational direction. In this case, if the receiving recess is formed by the opening of the discharge passage, the man-hour for processing the dedicated receiving recess can be omitted.

It is sectional drawing (IOI sectional view taken on the line of FIG. 2) of the high pressure pump by 1st Embodiment of this invention. It is the II-II sectional view taken on the line of FIG. It is the III-O-III sectional view taken on the line of FIG. It is the IV section expanded sectional view of FIG. 3 which shows the valve closing state of the non-return valve by 1st Embodiment of this invention. It is an expanded sectional view which shows the valve opening state of the non-return valve of FIG. It is the (a) top view of the non-return valve member by 1st Embodiment of this invention, (b) It is the BB sectional view taken on the line of (a). It is sectional drawing corresponding to FIG. 3 of the high pressure pump by 2nd Embodiment of this invention. It is the (a) top view of the non-return valve member by 2nd Embodiment of this invention, (b) It is the BB sectional view taken on the line of (a). It is sectional drawing corresponding to FIG. 3 of the high pressure pump by 3rd Embodiment of this invention. (A) Top view of non-return valve member by 3rd Embodiment of this invention, (b) It is the BB sectional view taken on the line of (a). It is an expanded sectional view which shows the valve closing state of the non-return valve by 4th Embodiment of this invention. It is an expanded sectional view showing the valve closing state of a check valve by a 5th embodiment of the present invention. It is an expanded sectional view which shows the valve closing state of the non-return valve by 6th Embodiment of this invention. It is an expanded sectional view which shows the valve opening state of the non-return valve of FIG. It is a top view of a check valve member according to a seventh embodiment of the present invention.

Hereinafter, a plurality of embodiments of a high-pressure pump of the present invention will be described with reference to the drawings. In the embodiments, substantially the same components are denoted by the same reference numerals and description thereof is omitted.
(First embodiment)
A high-pressure pump according to a first embodiment of the present invention will be described with reference to FIGS.
First, the overall configuration of the high-pressure pump 1 according to the present embodiment will be described mainly with reference to FIGS. The high-pressure pump 1 is used by being mounted on a vehicle, pressurizes fuel supplied from a fuel tank by a low-pressure pump, and discharges the fuel to a fuel rail to which an injector is connected. A pipe from the low pressure pump is connected to the upstream side of the fuel inlet 55 (see FIG. 2) of the high pressure pump 1.

In the following description, for the sake of convenience, the upper side of FIGS. 1 and 3 will be described as “upper” and the lower side will be described as “lower”.
As shown in FIGS. 1 to 3, the high-pressure pump 1 includes a pump body 10, a cylinder 20, a plunger unit 40, a suction valve unit 60, an electromagnetic drive unit 70, a discharge valve unit 80, and the like. Hereinafter, the structure of each part is demonstrated in order.

[Pump body 10 and cylinder 20]
The pump body 10 constitutes the outline of the high-pressure pump 1. Moreover, the plunger part 40 which is the lower part of the pump body 10 is inserted into a mounting hole of an engine (not shown). The high pressure pump 1 is driven by the power of the camshaft being transmitted to the plunger 41 via the tappet.
Hereinafter, the end surface on the plunger portion 40 side of the pump body 10 is referred to as a driving side end surface 101.

  The pump body 10 is formed with a cylinder insertion hole 11 penetrating along the central axis O (see FIG. 2), and a suction valve holder mounting hole 16 and a discharge valve holder mounting hole 18 orthogonal to the cylinder insertion hole 11. . A cylinder 20 is inserted into the cylinder insertion hole 11. A suction valve holder 61 and a discharge valve holder 81 described later are attached to the suction valve holder mounting hole 16 and the discharge valve holder mounting hole 18, respectively. As shown in FIG. 2, the suction valve holder mounting hole 16 and the discharge valve holder mounting hole 18 are arranged on the substantially opposite side with respect to the central axis O.

In the present embodiment, the communication passage 14 is formed so as to intersect the discharge valve holder mounting hole 18 in the vertical direction. The communication passage 14 cuts the pump body 10 in the axial direction, opens at the top to the bottom of the main fuel chamber 12, and opens to the drive side end face 101 at the bottom.
As shown in FIG. 2, an inlet plug hole 17, a discharge passage 15, and a discharge plug hole 19 are formed in a direction different from the suction valve holder mounting hole 16 and the discharge valve holder mounting hole 18. The inlet plug 53 is screwed into the inlet plug hole 17 while fixing the union 54. As a result, a fuel supply path is formed from the fuel inlet 55 through the union 54 and the inlet plug 53 to the inlet plug hole 17.

  In the discharge passage 15, a passage that communicates with the discharge plug hole 19 and extends in the radial direction (the left-right direction in FIG. 3) intersects with a passage that opens in the drive-side end surface 101 and extends in the axial direction. The discharge plug 56 is screwed into the discharge plug hole 19 while fixing the union 57. As a result, a fuel discharge path communicating from the discharge passage 15 through the discharge plug 56 and the union 57 to the discharge port 58 is formed. The high-temperature fuel discharged from the discharge port 58 is returned to the fuel tank or the like after being cooled by, for example, an external fuel cooler.

  A cylindrical cover 51 with a bottom is fastened and fixed to a cylindrical wall 104 formed in the upper part of the pump body 10, and a main fuel chamber 12 is formed inside the cylindrical wall 104 and the cover 51. An O-ring 52 for sealing fuel is provided between the upper end surface of the cylindrical wall 104 and the cover 51. The main fuel chamber 12 communicates with the inlet plug hole 17, and fuel is supplied from a fuel inlet 55 upstream of the fuel flow from a pressurizing chamber 22 described later.

  The main fuel chamber 12 is provided with a pulsation damper 50 in which the outer edges of two diaphragms are joined. In the pulsation damper 50, a gas having a predetermined pressure is sealed in an inner sealed space, and the two diaphragms are elastically deformed in the plate thickness direction in accordance with the change in the fuel pressure, whereby the fuel pressure pulsation in the main fuel chamber 12 is achieved. Reduce.

  The cylinder 20 is formed in a cylindrical shape, for example, by heat-treated martensitic stainless steel, and is inserted into the cylinder insertion hole 11 of the pump body 10 by press-fitting or shrink-fitting and fixed. The end of the cylinder 20 on the side of the main fuel chamber 12 is liquid-tightly closed by a plug 29 screwed into a female screw formed on the inner wall. The lower end portion 26 of the cylinder 20 protrudes below the drive side end surface 101, that is, on the side opposite to the main fuel chamber 12.

  A plunger 41 is slidably accommodated in the cylinder 20. A pressurizing chamber 22 in which fuel is pressurized is formed between the lower end surface 291 of the plug 29 and the pressurizing end 412 of the plunger 41. The cylinder 20 has a suction communication hole 23 and a discharge communication hole 24 communicating with the pressurizing chamber 22 at positions corresponding to the suction valve holder mounting hole 16 and the discharge valve holder mounting hole 18 of the pump body 10. Yes.

[Plunger part 40]
The plunger portion 40 includes a plunger 41, a fuel seal member 44, an upper seat 45, an oil seal 46, a lower seat 47, a plunger spring 48, and the like.
The plunger 41 of the present embodiment has a large-diameter portion 411 that slides along the inner wall of the cylinder 20 on the axial pressurizing chamber 22 side, and a small-diameter portion 413 on the opposite side of the pressurizing chamber 22. “Stepped shape”. The large diameter portion 411 and the small diameter portion 413 are formed coaxially. A pressurizing end 412 that is an end portion of the large diameter portion 411 faces the pressurizing chamber 22. A lower seat 47 is coupled to a drive end 414 that is an end of the small diameter portion 413.

  The fuel seal member 44 is attached so as to surround the small diameter portion 413. The fuel seal member 44 includes an inner peripheral Teflon (registered trademark) ring slidably contacting the outer peripheral surface of the small diameter portion 413 and an outer peripheral O ring, and the thickness of the fuel oil film around the small diameter portion 413 The fuel leakage to the engine due to the sliding of the plunger 41 is suppressed. In order for this fuel seal member 44 to function well, it is desirable to cool the surrounding fuel temperature below a predetermined temperature.

The configuration of the upper part of the upper sheet 45 will be described with reference to FIGS. The upper seat 45 has a flange portion 451 facing the drive side end face 101 of the pump body 10 and an outer cylinder portion 453 extending axially upward from the outer edge of the flange portion 451 at the upper portion, and the outer cylinder portion 453. Is fixed to the pump body 10 by welding, for example, to the outer wall 102 of the pump body 10. A check valve member 301 described later is sandwiched between the drive side end face 101 of the pump body 10 and the bottom face 452 of the flange 451.
As shown in FIGS. 1 and 3, the lower surface of the flange portion 451 of the upper seat 45 supports the upper end of the plunger spring 48. In addition, illustration of the plunger spring 48 is abbreviate | omitted in FIG.4, FIG.5 and the following equivalent figures.

In the middle part of the upper sheet 45, an intermediate cylinder part 454 extending from the inner edge of the flange part 451 to the lower side in the axial direction is provided. A space between the inner wall of the middle cylinder portion 454 and the lower end portion 26 of the cylinder 20 forms the auxiliary fuel chamber 13. That is, the upper seat 45 defines a boundary of the auxiliary fuel chamber 13 on the side opposite to the cylinder 20. In the auxiliary fuel chamber 13, the fuel leaked from the pressurizing chamber 22 through the sliding gap between the cylinder 20 and the plunger 41 accumulates.
Further, in the auxiliary fuel chamber 13 of the present embodiment, the volume obtained by multiplying the cross-sectional area difference between the large diameter portion 411 and the small diameter portion 413 by the moving distance of the plunger 41 changes as the plunger 41 reciprocates.

  Further, a fuel seal member 44 is accommodated around the small diameter portion 413 at the lower portion of the middle cylinder portion 454 of the upper seat 45. Further, an oil seal 46 is attached to the lower end portion of the upper seat 45 so as to surround the small diameter portion 413. The oil seal 46 is slidably in contact with the outer peripheral surface of the small-diameter portion 413, regulates the thickness of the oil film around the small-diameter portion 413, and suppresses oil leakage due to the sliding of the plunger 41.

  Thus, the upper seat 45 of the present embodiment has a function of holding the check valve member 301, a function of supporting the upper end of the plunger spring 48, a function of partitioning the boundary of the auxiliary fuel chamber 13, the fuel seal member 44, and It is a multifunctional member that also has a function of holding the oil seal 46. Among them, the upper seat 45 of the present embodiment corresponds to a “bottom cover member” described in the claims from the viewpoint of the function of holding the check valve member 301.

  Subsequently, the lower seat 47 coupled to the drive end 414 of the plunger 41 supports the lower end of the plunger spring 48. Plunger springs 48 whose both ends are locked to the upper sheet 45 and the lower sheet 47 function as a return spring for the plunger 41 and urge the plunger 41 against a tappet (not shown).

  The plunger 41 abuts against the cam of the camshaft via the tappet by the return spring function of the plunger spring 48, thereby reciprocating in the cylinder 20 along the camshaft profile in the axial direction. By the reciprocating movement of the plunger 41, the volume of the pressurizing chamber 22 changes, and fuel is sucked and pressurized.

[Suction valve section 60]
The intake valve portion 60 includes an intake valve holder 61, a valve seat member 62, an intake valve 63, and the like.
The suction valve holder 61 is formed in a cylindrical shape and is fixed to the suction valve holder mounting hole 16 of the pump body 10.
A valve seat member 62 is provided on the pressure chamber 22 side of the suction valve holder 61. The valve seat member 62 is a valve formed in the suction passage 64 for flowing the fuel supplied from the main fuel chamber 12 through the fuel passage 121 to the pressurization chamber 22 and the opening of the suction passage 64 on the pressurization chamber 22 side. A seat 65 is provided. Further, the valve seat member 62 has a hole that accommodates the shaft portion 632 of the suction valve 63 so as to be reciprocally movable. A seal member 66 is provided between the valve seat member 62 and the bottom inner wall of the suction valve holder mounting hole 16.

  The suction valve 63 has an umbrella part 631, a shaft part 632, and a flange part 633. The umbrella portion 631 can be seated on the valve seat 65 of the valve seat member 62. The shaft portion 632 is accommodated in the hole of the valve seat member 62 so as to be reciprocally movable. The flange portion 633 is provided on the side opposite to the umbrella portion 631 with respect to the shaft portion 632. The suction valve spring 67 is provided between the flange portion 633 and the valve seat member 62, and biases the suction valve 63 toward the valve seat 65.

[Electromagnetic drive unit 70]
The electromagnetic drive unit 70 includes a flange 71, a fixed core 72, a movable core 73, a rod 74, a coil 75, a rod spring 76, and the like.
The flange 71 is fixed to the outer wall of the suction valve holder 61. The movable core 73 is provided inside the suction valve holder 61 so as to be able to reciprocate. The rod 74 fixed to the movable core 73 can press the suction valve 63 toward the pressurizing chamber 22. The rod spring 76 biases the movable core 73 and the rod 74 toward the pressurizing chamber 22 side. The guide member 77 is fixed inside the suction valve holder 61 and supports the rod 74 so as to be capable of reciprocating in the axial direction.

The fixed core 72 is provided on the radially inner side of the coil 75 on the opposite side of the movable core 73 from the pressurizing chamber 22. When the coil 75 is energized through the terminal 781 of the connector 78, a magnetic flux flows through a magnetic circuit constituted by the movable core 73, the fixed core 72, the yoke 79, the flange 71 and the like, and the movable core 73 and the rod 74 are connected to the rod spring 76. It is magnetically attracted toward the fixed core 72 against the urging force.
On the other hand, when energization of the coil 75 is stopped, the magnetic flux flowing through the magnetic circuit described above disappears, and the movable core 73 and the rod 74 are urged toward the pressurizing chamber 22 by the urging force of the rod spring 76.

[Discharge valve unit 80]
The discharge valve unit 80 includes a discharge valve holder 81, a discharge valve 82, a valve seat 83, a discharge valve spring 84, and the like.
The discharge valve holder 81 has a discharge passage 85 inside and is fixed to the discharge valve holder mounting hole 18. A seal member 87 is provided between the discharge valve holder 81 and the bottom inner wall of the discharge valve holder mounting hole 18. A spring receiving member 86 is provided inside the discharge valve holder 81.
The discharge valve 82 is a ball valve, and can be seated on a valve seat 83 formed in a tapered shape on the inner wall of the discharge communication hole 24 of the cylinder 20. The discharge valve spring 84 is formed in a tapered shape whose diameter increases from the discharge valve 82 side toward the spring receiving member 86 side, and biases the discharge valve 82 toward the valve seat 83.

Next, the structure of the check valve member 301 which is a characteristic structure of the present invention will be described with reference to FIGS.
As shown in FIGS. 4 and 5, the check valve member 301 is sandwiched between the drive side end surface 101 of the pump body 10 and the bottom surface 452 of the flange portion 451 of the upper seat 45.

  As shown in FIG. 6, the check valve member 301 is configured by overlapping a first plate 311 and a second plate 321 which are manufactured by press-molding a steel plate, for example. Each of the first plate 311 and the second plate 321 has an annular shape having a central hole 34 through which the lower end portion 26 of the cylinder 20 is inserted. Further, the first plate 311 is formed with a relatively small plate thickness, and the second plate 321 is formed with a relatively thick plate thickness.

The first plate 311 has a reed valve portion 35 that is operable in the plate thickness direction, with the inner diameter side being the root portion and the outer diameter side being the tip portion.
The second plate 321 has communication passages 37 and 382 cut out in the radial direction from the central hole 34. When the second plate 321 is superimposed on the first plate 311, the entire reed valve portion 35 is included inside the communication path 37. That is, the communication passage 37 is formed to be slightly larger than the reed valve portion 35 so as not to interfere with the operation of the reed valve portion 35.

  The first plate 311 and the second plate 321 are sandwiched between the drive-side end surface 101 of the pump body 10 and the bottom surface 452 of the upper seat 45, and the position in the rotational direction is restricted. At this time, in the present embodiment, the first plate 311 is disposed on the upper seat 45 side (lower side in FIGS. 4 and 5), and the second plate 321 is disposed on the pump body 10 side (upper side in the same figure). Further, the reed valve portion 35 of the first plate 311 faces the opening 141 of the communication passage 14 and is disposed at a position where the opening 141 can be closed when operated on the drive side end face 101 side. Accordingly, the communication path 37 of the second plate 321 is arranged in the direction of the communication path 14.

  By the way, since the location where the check valve member 301 is installed is inside the engine mounting hole, if the amount of fuel accumulated in this part is large, the fuel temperature rises due to the heat transmitted from the engine side, and vapor may be generated. Increases nature. Therefore, it is preferable to set the size of the communication passages 37 and 382 to the minimum necessary so that the volume of the portion where the fuel is accumulated is as small as possible.

  As shown in FIG. 4, when the pressure difference obtained by subtracting the pressure in the communication passage 14 from the pressure in the auxiliary fuel chamber 13 is equal to or greater than a predetermined pressure, the reed valve portion 35 is pressed against the drive side end face 101 side, The valve 141 is closed with the opening 141 closed. As a result, the high temperature fuel in the auxiliary fuel chamber 13 is restricted from flowing into the main fuel chamber 12 via the communication passage 14. Therefore, the occurrence of vapor lock in the main fuel chamber 12 can be prevented.

On the other hand, as shown in FIG. 5, when the pressure difference obtained by subtracting the pressure in the communication passage 14 from the pressure in the auxiliary fuel chamber 13 falls below a predetermined pressure, the reed valve portion 35 is bent toward the upper seat 45 and opens. . The maximum lift amount L of the reed valve part 35 at this time corresponds to the plate thickness of the second plate 321. That is, the second plate 321 defines the maximum lift amount L of the reed valve portion 35 according to the plate thickness.
When the reed valve portion 35 is opened, the fuel F in the communication passage 14 flows into the communication passage 37 as indicated by the broken line arrow, and flows into the auxiliary fuel chamber 13 through the communication passage 37. As the low temperature fuel flows in, the fuel in the auxiliary fuel chamber 13 is cooled.

  In the present embodiment, the communication passage 14 and the discharge passage 15 are arranged in the V-shape with the central axis O as the center (see FIG. 2), and the communication passage 382 of the second plate 321 is discharged. It is arranged in the direction of the passage 15. Accordingly, the fuel in the auxiliary fuel chamber 13 is discharged to the discharge passage 15 via the communication passage 382.

  Next, the operation of the high-pressure pump 1 will be described. As the plunger 41 reciprocates, the high-pressure pump 1 repeats the intake stroke, the metering stroke, and the discharge stroke as follows, and pressurizes and discharges an amount of fuel necessary for the engine. In this process, the fuel leaking from the pressurizing chamber 22 via the sliding gap between the cylinder 20 and the plunger 41 becomes high temperature due to heat generation due to the depressurization and accumulates in the sub fuel chamber 13. Further, the temperature of the fuel in the auxiliary fuel chamber 13 rises due to heat transmitted from the engine.

  The present embodiment is characterized in that such high temperature fuel in the auxiliary fuel chamber 13 is prevented from flowing into the main fuel chamber 12 via the communication passage 14 and generating a vapor lock. Therefore, the following description will be made focusing on the basic operation of the high-pressure pump 1 and particularly the behavior of the high-temperature fuel in the auxiliary fuel chamber 13 in each stroke. As described above, the present embodiment is based on the premise that the plunger 41 has a stepped configuration including the large diameter portion 411 and the small diameter portion 413.

(1) Suction stroke When the plunger 41 descends from the top dead center toward the bottom dead center due to the rotation of the camshaft, the volume of the pressurizing chamber 22 increases and the fuel in the pressurizing chamber 22 is depressurized. The discharge valve 82 is seated on the valve seat 83 and closes the discharge passage 85. In the suction valve section 60, the suction valve 63 moves toward the pressurization chamber 22 against the biasing force of the suction valve spring 67 due to the differential pressure between the pressurization chamber 22 and the suction passage 64 and the biasing force of the rod spring 76. The valve is opened. By opening the intake valve 63, the fuel in the main fuel chamber 12 flows into the pressurizing chamber 22 via the intake passage 64.

In the intake stroke, the volume of the auxiliary fuel chamber 13 decreases due to the lowering of the plunger 41, and the pressure increases. On the other hand, the main fuel chamber 12 is decompressed because fuel is sucked into the pressurizing chamber 22 via the fuel passage 121 and the suction passage 64. Therefore, the pressure difference obtained by subtracting the pressure in the communication passage 14 from the pressure in the auxiliary fuel chamber 13 is increased, and the reed valve portion 35 of the check valve member 301 is closed.
Therefore, the high temperature fuel in the auxiliary fuel chamber 13 does not flow into the communication passage 14 but is discharged from the discharge passage 15 to the outside via the communication passage 382 of the check valve member 301.

(2) Metering stroke When the plunger 41 rises from the bottom dead center toward the top dead center due to the rotation of the camshaft, the volume of the pressurizing chamber 22 decreases. At this time, since energization to the coil 75 is stopped until a predetermined time, the rod 74 presses the suction valve 63 toward the pressurizing chamber 22 by the urging force of the rod spring 76. Therefore, the suction valve 63 is maintained in the open state. For this reason, the low-pressure fuel once sucked into the pressurizing chamber 22 is returned to the main fuel chamber 12. Therefore, the pressure in the pressurizing chamber 22 does not increase.

  In the metering stroke, the volume of the auxiliary fuel chamber 13 increases due to the rise of the plunger 41, and the pressure decreases. On the other hand, the pressure in the main fuel chamber 12 increases because the fuel in the pressurizing chamber 22 is returned. Accordingly, the pressure difference obtained by subtracting the pressure in the communication passage 14 from the pressure in the auxiliary fuel chamber 13 is reduced, and the reed valve portion 35 of the check valve member 301 is opened. Therefore, the low temperature fuel in the main fuel chamber 12 flows into the auxiliary fuel chamber 13 via the communication path 37, and the fuel temperature in the auxiliary fuel chamber 13 is lowered.

(3) Discharging stroke When the coil 41 is energized at a predetermined time while the plunger 41 rises from the bottom dead center toward the top dead center, the fixed core 72 and the movable core 73 are moved by the magnetic field generated in the coil 75. Magnetic attractive force is generated during When this magnetic attractive force becomes larger than the difference between the urging force of the suction valve spring 67 and the urging force of the rod spring 76, the movable core 73 moves to the fixed core side. Thereby, the pressing force of the rod 74 against the suction valve 63 is released.
Then, the suction valve 63 moves in the valve closing direction following the operation of the rod 74 by the biasing force of the suction valve spring 67 and the dynamic pressure of the low pressure fuel discharged from the pressurizing chamber 22 to the suction passage side. Sit on the valve seat 65. Thereby, the pressurizing chamber 22 and the suction passage 64 are shut off.

After the intake valve 63 is closed, the fuel pressure in the pressurizing chamber 22 becomes higher as the plunger 41 is raised, and the discharge valve 82 is opened. Thereby, the high-pressure fuel pressurized in the pressurizing chamber 22 is discharged from the fuel outlet 88. Note that energization of the coil 75 is stopped during the discharge stroke. Since the force that the fuel pressure in the pressurizing chamber 22 acts on the suction valve 63 is larger than the urging force of the rod spring 76, the suction valve 63 maintains the closed state.
Further, during the ascent of the plunger 41, the reed valve portion 35 of the check valve member 301 maintains the valve open state.

  As described above, in synchronization with the ascending and descending cycles of the plunger 41, the pressure in the auxiliary fuel chamber 13 changes relative to the pressure in the communication passage 14, and the reed valve portion 35 of the check valve member 301 opens and closes. Operate. When the reed valve portion 35 is opened, the fuel in the main fuel chamber 12 flows into the auxiliary fuel chamber 13 via the communication passage 14. When the reed valve portion 35 is closed, the fuel in the auxiliary fuel chamber 13 is discharged from the discharge passage 15. Is discharged. As a result, a unidirectional fuel flow is formed. That is, in the high-pressure pump 1, a secondary pumping action in the auxiliary fuel chamber 13 is generated, which is different from the main pumping action in the pressurizing chamber 22.

Next, the effect of this embodiment will be described.
(1) In the present embodiment, the high temperature fuel in the auxiliary fuel chamber 13 whose temperature has risen due to heat generation due to decompression of leaked fuel or heat transmitted from the engine side is caused to flow into the main fuel chamber 12 by the action of the check valve member 301. Without discharge from the discharge passage 15 to the outside of the high-pressure pump 1. Therefore, it is possible to prevent the vapor lock from occurring in the main fuel chamber 12.

  (2) In this embodiment, since the plunger 41 has a stepped configuration, the pumping action of sending fuel from the main fuel chamber 12 to the discharge passage 15 through the sub fuel chamber 13 by the reciprocating movement of the plunger 41. Is done. Therefore, the low temperature fuel in the main fuel chamber 12 can be actively flowed into the sub fuel chamber 13 to cool the fuel in the sub fuel chamber 13. Thereby, the fuel seal member 24 etc. can be made to function satisfactorily.

  (3) Since the check valve of this embodiment is constituted by the reed valve portion 35 of the check valve member 301, the space in the height direction can be minimized. Moreover, since it is pinched between the drive side end surface 101 of the pump body 10 and the bottom surface 452 of the upper seat 45, a dedicated member for attaching the check valve member is unnecessary.

  (4) The check valve member 301 of the present embodiment has two plates manufactured by press molding, that is, the first plate 311 on which the reed valve portion 35 is formed, and the position corresponding to the reed valve portion 35. The cut out second plate 321 is overlapped. Therefore, the maximum lift amount of the reed valve portion 35 can be easily adjusted by the thickness of the second plate 321. Moreover, the manufacturing cost of components can be reduced by press molding.

Hereinafter, other embodiment of this invention regarding the form of a non-return valve member is described in order. It is assumed that the check valve members of the second to seventh embodiments are manufactured by press molding. Moreover, it has the effect similar to the non-return valve member 301 of 1st Embodiment fundamentally.
(Second Embodiment)
The high-pressure pump 2 and the check valve member 302 according to the second embodiment of the present invention are shown in FIGS.
As shown in FIG. 8, the check valve member 302 differs from the check valve member 301 of the first embodiment in the configuration of the first plate 312 and the second plate 321 is substantially the same. The first plate 312 is formed with a notch 381 in the V-shaped direction with respect to the reed valve portion 35. A positioning projection 361 that protrudes from the plate surface is formed inside the notch 381 by bending the plate at a substantially right angle.

As shown in FIG. 7, the positioning protrusion 361 is inserted into the opening 151 of the discharge passage 15. Since a gap remains around the positioning protrusion 361 with respect to the circular opening 151, a passage for fuel discharged to the discharge passage 15 is secured by this gap. That is, in the present embodiment, the opening 151 of the discharge passage 15 corresponds to a “receiving recess” described in the claims.
Thereby, the position of the rotation direction of the first plate 312 with respect to the pump body 10 is positioned. Therefore, the reed valve portion 35 can be prevented from being displaced from the opening 141 of the communication passage 14.

(Third embodiment)
A high-pressure pump 3 and a check valve member 303 according to a third embodiment of the present invention are shown in FIGS.
As shown in FIG. 10, the check valve member 303 is substantially the same in the first plate 312 as the check valve member 302 of the second embodiment, and the configuration of the second plate 323 is different. Like the first plate 312, the second plate 323 has a positioning projection 362 that protrudes from the plate surface by bending the plate at a substantially right angle, like the first plate 312. The positioning protrusion 362 is provided at a position close to the positioning protrusion 361.
As shown in FIG. 9, the two positioning protrusions 361 and 362 are both inserted into the opening 151 of the discharge passage 15 while ensuring a fuel flow path.

  As a result, the check valve member 303 positions the first plate 312 and the second plate 323 in the rotational direction with respect to the pump body 10. Therefore, the reed valve portion 35 can be prevented from shifting from the opening 141 of the communication passage 14, and further, the reed valve portion 35 and the communication passage 37 can be prevented from shifting.

(Fourth and fifth embodiments)
In the check valve member 304 of the fourth embodiment shown in FIG. 11, the first plate 314 having the reed valve portion 354 is opposite to the check valve members 301, 302, 303 of the first to third embodiments. It arrange | positions at the pump body 10 side and the 2nd board 324 is arrange | positioned at the upper seat 45 side.
When the reed valve portion 354 is on the same plane as the main body of the first plate 314, the reed valve portion 354 closes the opening 141. Further, when the reed valve portion 354 is bent toward the upper seat 45 due to a pressure difference between the auxiliary fuel chamber 13 and the communication passage 14, the reed valve portion 354 is opened as shown in FIG. 11. The maximum lift amount L of the reed valve portion 354 at this time corresponds to the plate thickness of the second plate 324.

  As in the fourth embodiment, the check valve member 305 of the fifth embodiment shown in FIG. 12 has a first plate 315 arranged on the pump body 10 and a second plate 324 substantially the same as the fourth embodiment. Arranged on the upper sheet 45 side. The reed valve portion 355 formed on the first plate 315 is opened with a shape that is stretched almost straight from the root side to the tip side as compared with the reed valve portion 354 of the fourth embodiment. As described above, the degree of bending of the reed valve portion when the valve is opened may be appropriately adjusted depending on the material and the surface treatment.

(Sixth embodiment)
As shown in FIG. 13 and FIG. 14, the check valve member 306 of the sixth embodiment is a first plate 316 provided on the pump body 10 side and a first plate 316 provided on the upper seat 45 side. 2 plates 326 and three support plates 336 provided between the first plate 316 and the second plate 326. The support plate 336 is thicker than the first plate 316, and a restricting portion 39 is formed at a position corresponding to the reed valve portion 35. The restricting part 39 restricts the limit position when the reed valve part 35 is opened.
Thereby, deformation | transformation of the reed valve part 35 can be prevented and the flow path area at the time of valve opening can be ensured stably.

(Seventh embodiment)
As shown in FIG. 15, the check valve member 307 of the seventh embodiment is formed such that the reed valve portion 4 extends in the circumferential direction with respect to the check valve member 301 (see FIG. 6) of the first embodiment. ing. The communication passage relief groove 377 extends in the radial direction (upward in FIG. 15) from the central hole 34, then changes its direction in the circumferential direction, and is formed along the reed valve portion 357.
Thereby, since the length of the reed valve part 357 can be lengthened, it becomes advantageous to ensure the lift amount at the time of valve opening.

(Other embodiments)
(A) In the above embodiment, the opening 151 of the discharge passage 15 also serves as a receiving recess into which the positioning protrusions 361 and 362 of the check valve members 302 and 303 are inserted. In another embodiment, a receiving recess opening in the driving side end surface 101 of the pump body 10 may be formed separately from the discharge passage 15.
(A) The check valve member is not limited to press molding as in the above embodiment, and may be manufactured by a method such as cutting. The positioning protrusion is not limited to the method of bending the plate, and may be formed by press-fitting or welding a member such as a pin or pipe to the plate.

(C) The “bottom cover member” that holds the check valve member between the pump body 10 and the driving side end surface 101 is not limited to the form formed by the flange 451 of the upper seat 45 as in the above embodiment. It may be constituted by other dedicated members.
(D) The plunger is not limited to the stepped shape having the large diameter portion 411 and the small diameter portion 413 as shown in FIGS. 1 and 3 and the like, but may have a “stepless” shape with a constant outer diameter.

  (E) In the high-pressure pump 1 and the like of the above-described embodiment, the communication passage 14 and the discharge passage 15 are arranged in the V-shape around the central axis O. On the other hand, in other embodiments, the arrangement of the communication passage 14 and the discharge passage 15 may be set as appropriate. Further, the communication passage 14 may be formed independently without intersecting the discharge valve holder mounting hole 18. Corresponding to the arrangement of the communication passage 14 and the discharge passage 15, the arrangement of the reed valve portion 35 of the check valve member and the communication passage 382 on the discharge passage 15 side may be set as appropriate.

(F) The cylinder in which the plunger is reciprocally accommodated is not limited to the form in which the separate cylinder 20 is inserted into the pump body 10, and may be formed directly on the pump body.
(G) The configuration of each part of the high-pressure pump other than the configuration related to the check valve member is not limited to the above embodiment. For example, the pulsation damper 50 may not be provided in the main fuel chamber 12. The suction valve 63 may be a normally closed type instead of a normally open type as in the above embodiment.

  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.

1, 2, 3, ... high pressure pump,
10 ... pump body, 101 ... drive side end face,
12 ... Main fuel chamber, 13 ... Sub fuel chamber,
14 ・ ・ ・ Communication passage, 141 ・ ・ ・ Open, 15 ・ ・ ・ Discharge passage,
20 ... Cylinder, 22 ... Pressurizing chamber, 26 ... (Lower) end,
301-307... Check valve member,
35, 354, 355, 357 ... reed valve part,
41 ... plunger, 412 ... pressure end,
45 ... upper sheet (bottom cover member), 452 ... bottom face 55 ... fuel outlet.

Claims (7)

A plunger (41);
A cylinder (20) which slidably accommodates the plunger and forms a pressurizing chamber (22) facing a pressurizing end (412) which is one end of the plunger and in which fuel is pressurized. A secondary fuel chamber (13) is formed which faces an end (26) opposite to the pressurizing chamber and accumulates fuel leaked from the pressurizing chamber via a sliding gap between the cylinder and the plunger. A cylinder to be
A main fuel chamber (12) to which fuel is supplied from a fuel inlet (55) on the upstream side of the fuel flow from the pressurizing chamber, an end surface on the drive side that is the end surface on the opposite side to the pressurizing chamber in the axial direction (101) And a communication passage (14) communicating with the main fuel chamber (12) and the sub fuel chamber, and a discharge passage for discharging the fuel accumulated in the sub fuel chamber to the outside, which is opened at the driving end surface. A pump body (10) in which (15) is formed;
A bottom cover member (45) fixed to the pump body such that a bottom surface (452) faces the driving side end surface;
Reed valve portions (35, 354, 355, 357) which are sandwiched between the driving side end surface of the pump body and the bottom surface of the bottom cover member and can close the opening (141) of the communication passage. A check that allows the flow of fuel from the main fuel chamber to the sub fuel chamber in the communication passage and restricts the flow of fuel from the sub fuel chamber to the main fuel chamber by opening and closing the lead valve portion. A valve member (301-307);
A high-pressure pump (1, 2, 3) characterized by comprising: The check valve member is
A first plate (311-316) on which the reed valve portion is formed;
A position corresponding to the reed valve portion is cut away, and a second plate (321-326) that defines the maximum lift amount of the reed valve portion according to the plate thickness;
The high pressure pump according to claim 1, wherein the two are superposed. The check valve member (306)
The high-pressure pump according to claim 2, further comprising a support plate (336) having a restricting portion (39) for restricting a limit position when the reed valve portion is opened. The pump body has a receiving recess that opens to the driving side end surface at a position different from the communication passage,
The check valve members (302, 303)
Positioning projections (361, 362) for projecting toward the driving side end face and being inserted into the receiving recess to position the first plate or the second plate in the rotational direction with respect to the pump body are provided. 4. High-pressure pump (2, 3) according to claim 2 or 3, characterized in that The receiving recess is constituted by an opening (151) of the discharge passage;
The high-pressure pump according to claim 4, wherein the positioning protrusion is inserted into the opening of the discharge passage while securing a fuel flow path.   6. The high-pressure pump according to claim 4, wherein the positioning protrusion is formed by bending a plate-like member toward the driving side end face. The plunger has a large-diameter portion (411) that slides along the inner wall of the cylinder on the pressurizing chamber side in the axial direction, and a small-diameter portion (413) on the opposite side to the pressurizing chamber in the axial direction. Have
The high-pressure pump according to any one of claims 1 to 6, wherein a volume of the auxiliary fuel chamber is changed by a reciprocating movement of the plunger.

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