JP7139265B2 - High-pressure fuel supply pump and relief valve mechanism - Google Patents

Description

The present invention relates to a high pressure fuel supply pump and a relief valve mechanism.

As an example of a relief valve for fuel distribution pipes, the differential pressure between the inside and outside of the fuel distribution pipe can be reduced to ensure pressure regulation performance while using a ball valve body, and the structure can be simplified by using the ball valve body. , Patent Document 1 discloses a valve body of a relief valve fixed to a fuel distribution pipe of a cylinder injection type engine. A valve spring for biasing in the valve direction is incorporated, the valve body is a ball valve body, and a throttle hole having an opening area smaller than the passage area of the valve seat is provided in the fuel passage on the downstream side of the ball valve body. .

JP-A-2000-240529

In order to improve environmental friendliness, the injection pressure of fuel injection valves in internal combustion engines tends to increase. As the injection pressure increases, the size of the relief spring mounted on the high-pressure fuel supply pump increases. In addition, when the fuel is affected by compressibility, there is a problem that the discharge efficiency (the ratio of the actual discharge flow rate to the displacement volume of the plunger) decreases. In order to reduce this compressibility effect, it is required to reduce the volume of the pressurization chamber.

In Patent Document 1, the male threaded portion of the valve body fixed to the fuel distribution pipe by screwing is provided at a position that does not radially overlap the valve seat, and the valve seat is deformed due to the distortion of the male threaded portion due to the screwing force of the valve body. prevent

However, in the technique disclosed in Patent Document 1, the cylindrical valve seat is inserted into the valve body and fixed to the valve seat press-fitting hole by press-fitting. It is structured to receive In order to suppress deformation of the seat, it is necessary to secure a large relief portion into which the outer peripheral portion of the valve seat is not press-fitted.

That is, conventionally, deformation of the seat portion of the relief seat member on which the relief valve is seated could not be suppressed with a compact relief seat member.

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-pressure fuel supply pump or the like which is a compact relief sheet member and which can suppress deformation of the seat portion of the relief sheet member.

To achieve the above object, one example of the present invention is a high-pressure fuel supply pump having a relief valve mechanism, the relief valve mechanism comprising a relief valve and a relief seat member on which the relief valve is seated. , the outer peripheral portion of the relief seat member on the side of the relief valve has a U-shaped groove portion including an inclined surface that is a side surface of a truncated cone whose diameter is reduced toward the relief valve side, and the groove portion on the side opposite to the relief valve The outer peripheral portion of the relief seat member has a press-fit portion that is press-fitted into a member arranged on the outer periphery thereof, and the outer peripheral portion of the relief seat member on the side of the relief valve is larger than the maximum outer diameter of the valve holder, Further, a protrusion having an outer diameter smaller than that of the press-fit portion is formed in the radial direction .

According to the present invention, deformation of the seat portion of the relief sheet member can be suppressed with a compact relief sheet member. Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

1 is a configuration diagram of an engine system to which a high-pressure fuel supply pump according to Example 1 of the present invention is applied; FIG. 1 is a longitudinal sectional view of a high-pressure fuel supply pump according to Embodiment 1 of the present invention; FIG. 1 is a horizontal cross-sectional view of a high-pressure fuel supply pump according to Embodiment 1 of the present invention, viewed from above; FIG. FIG. 2 is a vertical cross-sectional view of the high-pressure fuel supply pump according to Embodiment 1 of the present invention, viewed from a direction different from that of FIG. 2 ; FIG. 4 is an enlarged vertical cross-sectional view of the electromagnetic intake valve mechanism of the high-pressure fuel supply pump according to Embodiment 1 of the present invention, showing a state where the electromagnetic intake valve mechanism is in an open state; FIG. 4 is an enlarged vertical cross-sectional view of the relief valve mechanism of the high-pressure fuel supply pump according to Embodiment 1 of the present invention, showing a state where the relief valve mechanism is in a closed state; FIG. 6 is an enlarged vertical cross-sectional view of the relief valve mechanism of the high-pressure fuel supply pump according to Embodiment 2 of the present invention, showing a state where the relief valve mechanism is in a closed state; FIG. 5 is a longitudinal sectional view of a high-pressure fuel supply pump according to Embodiment 3 of the present invention;

High-pressure fuel supply pumps according to first to third embodiments of the present invention will be described below with reference to the drawings.

<Example 1>
Embodiment 1 A high-pressure fuel supply pump according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 6. FIG. First, the system configuration and operation of the high-pressure fuel supply pump of this embodiment will be described with reference to FIGS. 1 to 5. FIG.

FIG. 1 is a configuration diagram of an engine system to which a high-pressure fuel supply pump is applied, FIG. 2 is a vertical cross-sectional view of the high-pressure fuel supply pump, FIG. 3 is a horizontal cross-sectional view seen from above the high-pressure fuel supply pump, and FIG. FIG. 5 is a vertical cross-sectional view of the fuel supply pump viewed from a different direction from FIG. 2, and FIG. 5 is an enlarged vertical cross-sectional view of the electromagnetic intake valve mechanism of the high-pressure fuel supply pump, showing the electromagnetic intake valve mechanism in the open state.

In FIG. 1, the portion surrounded by the dashed line indicates the main body (pump body 1) of the high-pressure fuel supply pump. Mechanisms/parts shown within broken lines in FIG.

Fuel in the fuel tank 20 is pumped up by a feed pump 21 based on a signal from an engine control unit 27 (hereinafter referred to as ECU). This fuel is pressurized to a suitable feed pressure and sent through a fuel line 28 to the low pressure fuel inlet 10a of the high pressure fuel supply pump.

The fuel passing through the intake joint 50 (FIG. 4) from the low-pressure fuel intake port 10a passes through the low-pressure fuel intake port 10b, the pressure pulsation reduction mechanism 9, and the intake passage 10d to the electromagnetic intake valve mechanism 300 that constitutes a variable displacement mechanism. It reaches port 31b.

The fuel that has flowed into the electromagnetic suction valve mechanism 300 passes through the suction port that is opened and closed by the suction valve 30 and flows into the pressurization chamber 11 .

Here, the plunger 2 is energized to reciprocate by the cam 93 (FIG. 2) of the engine. Due to this reciprocating motion of the plunger 2, fuel is sucked from the intake valve 30 during the downward stroke of the plunger 2, and the fuel is pressurized during the upward stroke.

Fuel is pumped through the discharge valve mechanism 100 to the common rail 23 on which the pressure sensor 26 is mounted.

Based on a signal from the ECU 27, the injector 24 injects fuel into the engine.

This embodiment is a high-pressure fuel supply pump that is applied to a so-called direct injection engine system in which an injector 24 directly injects fuel into a cylinder of an engine.

The high-pressure fuel supply pump discharges supplied fuel at a desired fuel flow rate according to a signal from the ECU 27 to the electromagnetic intake valve mechanism 300 .

As shown in FIGS. 2 and 4, the high-pressure fuel supply pump of this embodiment is fixed in close contact with the high-pressure fuel supply pump mounting portion 90 of the internal combustion engine. More specifically, a mounting flange 1a provided on the pump body 1 of FIG. 3 is formed with holes 1b for fixing with bolts. It is closely attached to and fixed to the high-pressure fuel supply pump mounting portion 90 of the engine.

An O-ring 61 is fitted into the pump body 1 for sealing between the high-pressure fuel supply pump mounting portion 90 and the pump body 1, and prevents engine oil from leaking to the outside.

A cylinder 6 that guides the reciprocating motion of the plunger 2 and forms a pressure chamber 11 together with the pump body 1 is attached to the pump body 1 . That is, the plunger 2 changes the volume of the pressure chamber 11 by reciprocating inside the cylinder 6 . Also provided are an electromagnetic intake valve mechanism 300 for supplying fuel to the pressurizing chamber 11 and a discharge valve mechanism 100 for discharging fuel from the pressurizing chamber 11 to the discharge passage.

The cylinder 6 is press-fitted into the pump body 1 at its outer peripheral side. Further, at the fixed portion 6a, the pump body 1 is deformed toward the inner periphery, and the cylinder 6 is pressed upward in the figure, and the fuel pressurized in the pressure chamber 11 at the upper end surface of the cylinder 6 is at a low pressure. It is sealed to prevent leakage to the side.

A tappet 92 is provided at the lower end of the plunger 2 to convert the rotary motion of a cam 93 attached to the camshaft of the internal combustion engine into vertical motion and transmit the vertical motion to the plunger 2 . The plunger 2 is pressed against the tappet 92 by the spring 4 via the retainer 15 . As a result, the plunger 2 can be reciprocated up and down as the cam 93 rotates.

A plunger seal 13 held at the lower end portion of the inner periphery of the seal holder 7 is installed in a state of slidably contacting the outer periphery of the plunger 2 at the lower portion of the cylinder 6 in the drawing. As a result, when the plunger 2 slides, the fuel in the auxiliary chamber 7a is sealed and prevented from flowing into the internal combustion engine. At the same time, it prevents the lubricating oil (including engine oil) that lubricates the sliding parts in the internal combustion engine from flowing into the pump body 1 .

As shown in FIGS. 3 and 4, a suction joint 50 is attached to the side surface of the pump body 1 of the high-pressure fuel supply pump. The intake joint 50 is connected to a low-pressure pipe that supplies fuel from the fuel tank 20 of the vehicle, from which the fuel is supplied to the inside of the high-pressure fuel supply pump.

The fuel that has passed through the low-pressure fuel inlet 10a passes through the low-pressure fuel inlet 10b vertically communicating with the pump body 1 shown in FIG.

The pressure pulsation reducing mechanism 9 is arranged between the damper cover 14 and the upper end surface of the pump body 1 and supported from below by a holding member 9b arranged on the upper end surface of the pump body 1 . Specifically, the pressure pulsation reduction mechanism 9 is configured by stacking two diaphragms, and a gas of 0.3 MPa to 0.6 MPa is enclosed therein, and the outer peripheral edge is fixed by welding. . For this reason, the outer peripheral edge is thin, and the thickness increases toward the inner peripheral side.

A protrusion is formed on the upper surface of the holding member 9b for fixing the outer peripheral edge of the pressure pulsation reduction mechanism 9 from below. On the other hand, on the lower surface of the damper cover 14, a projection of a holding member 9a is arranged for fixing the outer peripheral edge of the pressure pulsation reducing mechanism 9 from above. These convex portions are formed in a circular shape, and the pressure pulsation reduction mechanism 9 is fixed by being sandwiched between these convex portions. In this embodiment, the damper cover 14 and the holding member 9a are integrated, but they may be separate.

The damper cover 14 is press-fitted to the outer edge of the pump body 1 and fixed. In this manner, damper chambers 10c are formed on the upper and lower surfaces of the pressure pulsation reducing mechanism 9 and communicate with the low-pressure fuel inlets 10a and 10b.

A passage is formed in the holding members 9a and 9b to communicate the upper side and the lower side of the pressure pulsation reduction mechanism 9, whereby the damper chamber 10c is formed on the upper and lower surfaces of the pressure pulsation reduction mechanism 9.

After passing through the damper chamber 10c, the fuel then reaches the intake port 31b of the electromagnetic intake valve mechanism 300 through the intake passage 10d formed in vertical communication with the pump body 1. As shown in FIG. The intake port 31b is formed so as to vertically communicate with the seat member 31 forming the intake valve seat 31a.

As shown in FIG. 3 , the discharge valve mechanism 100 provided at the outlet of the pressurizing chamber 11 includes a discharge valve seat 101 , a discharge valve 102 contacting and separating from the discharge valve seat 101 , and the discharge valve 102 facing the discharge valve seat 101 . It is composed of a discharge valve spring 103 that biases the discharge valve 102 and a discharge valve stopper 104 that determines the stroke (movement distance) of the discharge valve 102 . The discharge valve stopper 104 and the pump body 1 are welded together at a contact portion 105 to block fuel from the outside.

When there is no fuel pressure difference between the pressure chamber 11 and the discharge valve chamber 12a, the discharge valve 102 is pressed against the discharge valve seat 101 by the biasing force of the discharge valve spring 103 and is closed.

The discharge valve 102 opens against the force of the discharge valve spring 103 only when the fuel pressure in the pressure chamber 11 becomes higher than the fuel pressure in the discharge valve chamber 12a. High-pressure fuel in the pressure chamber 11 is discharged to the common rail 23 through the discharge valve chamber 12a, the fuel discharge passage 12b, and the fuel discharge port.

When the discharge valve 102 is opened, it comes into contact with the discharge valve stopper 104 and its stroke is limited. Therefore, the stroke of the discharge valve 102 is appropriately determined by the discharge valve stopper 104 . As a result, it is possible to prevent the fuel discharged under high pressure into the discharge valve chamber 12a from flowing back into the pressurization chamber 11 again due to delay in closing the discharge valve 102 due to an excessively large stroke. Decrease can be suppressed.

Further, when the discharge valve 102 repeats opening and closing movements, the discharge valve stopper 104 is guided by the outer peripheral surface of the discharge valve stopper 104 so that the discharge valve 102 moves only in the stroke direction. By doing so, the discharge valve mechanism 100 functions as a check valve that restricts the flow direction of the fuel.

As described above, the pressurizing chamber 11 is composed of the pump body 1 , the electromagnetic suction valve mechanism 300 , the plunger 2 , the cylinder 6 and the discharge valve mechanism 100 .

FIG. 5 shows a detailed configuration of the electromagnetic intake valve mechanism 300. As shown in FIG.

When the plunger 2 is moved in the direction of the cam 93 by the rotation of the cam 93 and is in the intake stroke state, the volume of the pressurizing chamber 11 increases and the fuel pressure in the pressurizing chamber 11 decreases. In this stroke, when the fuel pressure in the pressurizing chamber 11 becomes lower than the pressure in the intake port 31b, the intake valve 30 is opened. The opening 30a shows the maximum degree of opening, and the suction valve 30 contacts the stopper 32 at this time.

By opening the intake valve 30, the opening 31c formed in the seat member 31 opens. The fuel flows through the opening 31c and into the pressure chamber 11 through a hole 1f formed in the pump body 1 laterally. Note that the hole 1 f also constitutes a part of the pressurizing chamber 11 .

After the plunger 2 completes the suction stroke, the plunger 2 turns to ascending motion and shifts to the ascending stroke. At this time, the electromagnetic coil 43 remains in a non-energized state, and no magnetic biasing force acts. The rod biasing spring 40 biases the rod convex portion 35a projecting on the outer diameter side of the rod 35, and is set to have a necessary and sufficient biasing force to keep the intake valve 30 open in the non-energized state. there is

The volume of the pressurization chamber 11 decreases as the plunger 2 moves upward. In this state, the fuel that has once been sucked into the pressurization chamber 11 flows through the opening 30a of the intake valve 30, which is in the open state, into the intake passage. Since the pressure is returned to 10d, the pressure in the pressurizing chamber 11 does not rise. This stroke is called a return stroke.

In this state, when a control signal from the ECU 27 is applied to the electromagnetic intake valve mechanism 300, current flows through the electromagnetic coil 43 through the terminal 46 (FIG. 2). As a result, a magnetic attraction force acts between the magnetic core 39 and the anchor 36, and the magnetic core 39 and the anchor 36 come into contact with each other at the magnetic attraction surface S (FIG. 5). The magnetic attraction force overcomes the biasing force of the rod biasing spring 40 to bias the anchor 36 , and the anchor 36 engages with the rod protrusion 35 a to move the rod 35 away from the intake valve 30 .

At this time, the intake valve 30 is closed by the fluid force due to the urging force of the intake valve urging spring 33 and the fuel flowing into the intake passage 10d.

After the valve is closed, the fuel pressure in the pressurizing chamber 11 rises with the upward motion of the plunger 2, and when it reaches or exceeds the pressure in the fuel discharge port 12, high-pressure fuel is discharged through the discharge valve mechanism 100 to the common rail 23. supplied. This stroke is called a discharge stroke.

That is, the upward stroke from the lower start point to the upper start point of the plunger 2 consists of a return stroke and a discharge stroke. By controlling the timing of energization of the electromagnetic coil 43 of the electromagnetic intake valve mechanism 300, the amount of high-pressure fuel to be discharged can be controlled.

If the timing of energizing the electromagnetic coil 43 is advanced, the proportion of the return stroke in the compression stroke is small and the proportion of the discharge stroke is large. That is, less fuel is returned to the intake passage 10d, and more fuel is discharged at high pressure.

On the other hand, if the energization timing is delayed, the ratio of the return stroke in the compression stroke is large and the ratio of the discharge stroke is small. That is, more fuel is returned to the intake passage 10d, and less fuel is discharged at high pressure. The timing of energizing the electromagnetic coil 43 is controlled by a command from the ECU 27 .

By controlling the timing of energization of the electromagnetic coil 43 as described above, the amount of fuel discharged at high pressure can be controlled to the amount required by the internal combustion engine.

A pressure pulsation reducing mechanism 9 is installed in the damper chamber 10c (low-pressure fuel chamber) to reduce pressure pulsation generated in the high-pressure fuel supply pump from reaching the fuel pipe 28. FIG. When the fuel that has once flowed into the pressurization chamber 11 is returned to the intake passage 10d through the intake valve 30 in the open state again for capacity control, the fuel returned to the intake passage 10d causes pressure pulsation in the damper chamber 10c. Occur. However, the pressure pulsation reduction mechanism 9 provided in the damper chamber 10c is formed of a metal diaphragm damper in which two corrugated disk-shaped metal plates are pasted together at their outer circumferences and an inert gas such as argon is injected inside. The pressure pulsation is absorbed and reduced by the expansion and contraction of this metal damper.

The plunger 2 has a large-diameter portion 2a and a small-diameter portion 2b (FIG. 2), and the volume of the pre-chamber 7a increases and decreases as the plunger reciprocates. The auxiliary chamber 7a communicates with the damper chamber 10c through a fuel passage 10e. Fuel flows from the sub chamber 7a to the damper chamber 10c when the plunger 2 is lowered, and from the damper chamber 10c to the sub chamber 7a when the plunger 2 is raised.

As a result, it is possible to reduce the flow rate of fuel into and out of the pump during the suction stroke or return stroke of the pump, and has the function of reducing the pressure pulsation generated inside the high-pressure fuel supply pump.

Next, the relief valve mechanism 200A shown in FIGS. 2 and 3 etc. will be described.

The relief valve mechanism 200A comprises a relief seat 201, a valve 202, a valve holder 203, a relief spring 204 and a relief body 205.

The relief sheet 201 is provided with a tapered sheet portion 201a. The valve 202 (relief valve) is seated on the seat portion 201a of the relief seat 201 (relief seat member).

The valve 202 receives the load of the relief spring 204 via the valve holder 203, is pressed against the seat portion 201a, and cooperates with the seat portion 201a to shut off the fuel. The valve opening pressure of valve 202 is determined by the load of relief spring 204 .

The relief sheet 201 is press-fitted and fixed to the relief body 205, and is a mechanism for adjusting the load of the relief spring 204 depending on the press-fit position.

When the fuel in the pressurization chamber 11 is pressurized and the discharge valve 102 is opened, the high-pressure fuel in the pressurization chamber 11 passes through the discharge valve chamber 12a and the fuel discharge passage 12b and is discharged from the fuel discharge port 12. .

The fuel discharge port 12 is formed in a discharge joint 60, and the discharge joint 60 is welded and fixed to the pump body 1 at a welded portion 62 (FIG. 2) to secure a fuel passage. In this embodiment, the relief valve mechanism 200A is arranged in the space formed inside the discharge joint 60. As shown in FIG. That is, the outermost diameter portion of the relief valve mechanism 200A (in this embodiment, the outermost diameter portion of the relief body 205) is arranged inside the inner diameter portion of the discharge joint 60, and the pump body 1 is placed from above. As can be seen, the relief valve mechanism 200A is arranged so as to at least partially overlap the discharge joint 60 in its axial direction.

As a result, even if the shape of the discharge joint 60 changes, there is no need to change the shape of the relief valve mechanism 200A accordingly, so that cost reduction can be achieved.

That is, in this embodiment, as shown in FIG. 2, a first hole 1c (horizontal hole) is formed from the outer peripheral surface of the pump body 1 toward the inner peripheral side in a direction perpendicular to the axial direction of the plunger (horizontal direction). The relief valve mechanism 200A is arranged by press-fitting the relief body 205 into the first hole 1c. Thus, the high-pressure fuel supply pump of this embodiment has the relief valve mechanism 200A.

In this embodiment, it communicates with the first hole 1c, and when the relief valve mechanism 200A is opened, pressurizes the fuel in the discharge side passage that is pressurized in the pressure chamber 11 and discharged from the discharge valve 102. A second hole 1 d (horizontal hole) for returning to the chamber 11 is formed in the pump body 1 .

When the pressure of the fuel in the common rail 23 or downstream of the discharge valve mechanism 100 exceeds a set value, the valve 202 is opened to open the discharge side passage (fuel discharge port 12) and the internal space of the relief valve mechanism 200A. communicates with. A valve holder 203 and a relief spring 204 are arranged in this internal space. A hole 205b is formed in the center of the relief body 205 when viewed in the axial direction of the relief valve mechanism 200A, thereby connecting the internal space of the relief body 205 and the relief passage 1g formed by the second hole 1d.

When the valve 202 opens, the fuel in the internal space of the relief body 205 flows into the pressurization chamber 11 through the hole 205b in the center of the relief body 205 and the relief passage 1g.

During the pressurization stroke, pressure loss occurs due to the fuel discharge valve mechanism 100 and the fuel discharge passage 12b, which are provided between the fuel discharge port 12 and the pressurization chamber 11, when the fuel is discharged. An overshoot above the fuel outlet 12 pressure may occur. Due to this overshoot, the pressure at the fuel discharge port during the pressurization stroke fluctuates greatly.

However, in the case of the configuration of this embodiment, in which abnormal fuel is relieved to the high pressure side, the pressure at the fuel discharge port 12 increases during the pressurizing stroke as described above, but the outlet of the relief valve mechanism 200A is located in the pressurizing chamber 11. Therefore, the pressure in the pressurizing chamber 11 also increases, and the differential pressure between the inlet and outlet of the relief valve mechanism 200A does not exceed the set pressure of the valve 202 by the relief spring 204, so the valve 202 does not open.

On the other hand, since no fuel is discharged into the common rail 23 during the intake stroke/return stroke, the pressure at the fuel discharge port does not fluctuate greatly. Therefore, it is not necessary to set the relief valve set load in consideration of the overshoot in which the pressure in the pressurizing chamber 11 becomes higher than the pressure in the fuel discharge port 12 . If the set load of the relief valve is increased, the pressure resistance design of the high-pressure area such as the common rail 23 must be increased accordingly, and the increased weight tends to worsen the fuel efficiency. Therefore, by returning the fuel to the pressurization chamber 11, there is an effect of suppressing the fuel consumption.

When the high-pressure fuel supply pump is operating normally, the fuel pressurized by the pressurizing chamber 11 passes through the fuel discharge passage 12b and is discharged from the fuel discharge port 12 at high pressure.

Immediately after the start of the pressurizing stroke, the pressure in the pressurizing chamber 11 rises sharply to exceed the pressure in the common rail 23, and the discharge valve 102, which has been closed by the common rail pressure, opens accordingly. Along with this, the pressure of the fuel discharge port 12 also rises.

At this time, the pressure is measured by a pressure sensor 26 mounted inside the common rail 23, and by adjusting the discharge amount of the high-pressure fuel supply pump and the injector 24 based on the measurement result, the pressure inside the common rail 23 is The pressure is adjusted so as to reach the target pressure while fluctuating.

In this embodiment, the minimum load applied to the valve 202 by the relief spring 204 and the pressure in the pressurizing chamber 11 is set to be larger than the maximum load applied to the valve 202 by the internal pressure of the common rail 23. . That is, the pressure at the fuel discharge port 12, which is the inlet of the relief valve mechanism 200A, is set so as not to exceed the valve opening pressure, and the relief valve mechanism 200A does not open.

Next, a case where abnormally high pressure fuel is generated will be described.

Due to a malfunction of the electromagnetic intake valve mechanism 300 of the high-pressure fuel supply pump, the pressure at the fuel discharge port 12 becomes abnormally high, and when it becomes higher than the valve opening pressure of the relief valve mechanism 200A, the abnormally high-pressure fuel flows through the second hole 1d. is relieved to the pressurizing chamber 11. As a result, even if the electromagnetic intake valve mechanism 300 malfunctions, the pressure of the fuel discharge port 12 remains below a certain value, so that the common rail 23 and the like are not damaged by the high pressure.

Next, the configuration of the relief valve mechanism 200A will be described in detail using FIG. FIG. 6 is an enlarged vertical cross-sectional view of the relief valve mechanism of the high-pressure fuel supply pump of this embodiment, showing the relief valve mechanism in a closed state.

In the relief valve mechanism 200A of this embodiment, in the direction of fuel flow, ie, the axial direction, a seat portion 201a on which a valve 202 is seated is provided on the inner peripheral side of the relief seat 201, and a fuel passage 201b is provided on the upstream side of the seat portion 201a. is formed.

On the outer peripheral side of the relief sheet 201, a projecting portion 201c is formed near the seat portion 201a to reduce the volume of the pressurizing chamber 11 and suppress a decrease in discharge efficiency. is provided with a groove portion 201d that forms a gap with the relief body 205 in the radial direction. Further, a press-fitting portion 201e that is press-fitted into the inner peripheral portion of the relief body 205 is formed on the downstream side in the axial direction.

That is, as shown in FIG. 6, the outer peripheral portion of the relief seat 201 (relief seat member) on the side opposite to the valve 202 (relief valve) is a press-fitting portion that is press-fitted into a member (relief body 205) arranged on the outer periphery. 201e. The outer peripheral portion of the relief seat 201 (relief seat member) on the valve 202 (relief valve) side forms a protrusion 201c having an outer diameter smaller than that of the press-fitting portion 201e.

As a result, the volume of the pressurizing chamber 11 can be reduced, and a decrease in discharge efficiency can be suppressed. In addition, since a gap is formed between the projection 201c and the member (relief body 205) arranged on the outer periphery of the relief sheet 201, the projection 201c is directly connected to the member arranged on the outer periphery of the relief sheet 201. Not subject to external force.

As described above, the relief sheet 201 (relief sheet member) has a press-fit portion 201e that is press-fitted into the relief body 205 that accommodates the valve 202 (relief valve) and the relief sheet 201 (relief sheet member). As a result, the relief valve mechanism 200A is modularized, facilitating assembly of the high-pressure fuel supply pump.

If a gap occurs between the seat portion 201a and the valve 202, the fuel cannot be shut off. In this case, the fuel in the common rail 23 returns to the pressurizing chamber 11 through the seat portion 201a and the second hole 1d. As a result, fuel cannot be supplied to the injector 24, which causes engine malfunction. In addition, even if the amount returned to the pressurization chamber 11 is very small, it becomes difficult to maintain the pressure in the common rail 23, and the ride comfort is affected, such as the time required to restart the engine during idling stop or the like. Also, when the fuel passes through the seat portion 201a, erosion due to cavitation is generated, destroying the seat portion 201a, which also causes engine malfunction.

In the relief valve mechanism 200A of this embodiment, the groove portion 201d can make it difficult to transmit the deformation of the press-fitting portion 201e when it is press-fitted into the relief body 205 to the seat portion 201a. A configuration can be employed in which no gap is formed between the seat portion 201 a and the valve 202 .

In addition, in the relief sheet 201 provided with the groove portion 201d, the distance between the seat portion 201a and the press-fitting portion 201e can be set shorter than in the structure for avoiding press-fitting of the outer peripheral portion of the seat described in the prior art, thereby improving the layout. becomes possible.

Regarding the shape of the groove portion 201d, the surface 201f is parallel to the surface perpendicular to the axial direction, and the surface 201g is inclined from the downstream side to the upstream side in the outer diameter direction when viewed in the axial direction. The inventors of the present application have found from analysis results and the like that the deformation of can be suppressed most effectively.

That is, in this embodiment, as shown in FIG. 6, the groove portion 201d includes a surface 201g (inclined surface). As a result, deformation from the press-fit portion 201e is less likely to be transmitted to the seat portion 201a, and deformation of the seat portion 201a can be suppressed. Specifically, the surface 201g (inclined surface) is a side surface of a truncated cone whose diameter is reduced toward the valve 202 (relief valve) side. Thereby, deformation of the seat portion 201a can be suppressed and the groove portion 201d can be easily formed.

With the configuration as described above, the relief valve can reliably shut off the fuel while suppressing a decrease in discharge efficiency, achieve residual pressure retention characteristics, and suppress damage to the seat portion due to cavitation. It is possible to provide a high pressure fuel supply pump with mechanism 200A. In addition, the high-pressure fuel supply pump can be made to be capable of coping with even higher pressures of fuel in the future.

In this embodiment, as described above, the outer peripheral portion of the relief sheet 201 (relief sheet member) on the valve 202 (relief valve) side has the groove 201d. Accordingly, even if the distance between the seat portion 201a and the press-fitting portion 201e is shortened, deformation from the press-fitting portion 201e is less likely to be transmitted to the seat portion 201a, and deformation of the seat portion 201a can be suppressed. Further, in this embodiment, the downstream side of the relief valve mechanism 200A is connected to the pressurizing chamber 11 . As a result, the pressure in the pressure chamber 11 can be used when the valve is closed, so the relief spring 204 can be made smaller.

As described above, according to the present embodiment, deformation of the seat portion 201a of the relief sheet 201 can be suppressed with the compact relief sheet 201 (relief sheet member).

<Example 2>
A high-pressure fuel supply pump according to Embodiment 2 of the present invention will be described with reference to FIG.

The same reference numerals are given to the same configurations as in the first embodiment, and the description thereof is omitted. The same applies to the embodiments after the present embodiment.

The relief valve mechanism 200B of the high-pressure fuel supply pump of this embodiment does not use the relief body 205, unlike the first embodiment described above. A holder 203 and a relief spring 204 are inserted, and the relief sheet 201 is also directly press-fitted into the first hole 1c.

That is, the relief sheet 201 (relief sheet member) has a press-fitting portion 201e that is press-fitted into the pump body 1 that houses the relief valve mechanism 200B. As a result, the number of parts can be reduced, and the manufacturing cost of the high-pressure fuel supply pump can be reduced. In the present embodiment, the outer peripheral portion of the relief seat 201 (relief seat member) on the side of the valve 202 (relief valve) and the member (pump body 1 forming the first hole 1c) arranged on the outer periphery thereof. A gap is formed therebetween, and the outer peripheral portion of the relief sheet 201 on the valve 202 side has a groove portion 201d.

The effects obtained by the high-pressure fuel supply pump of this embodiment are the same as those of the high-pressure fuel supply pump of the first embodiment described above.

<Example 3>
Embodiment 3 A high-pressure fuel supply pump according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 8 is a longitudinal sectional view of the high-pressure fuel supply pump of this embodiment.

In the high-pressure fuel supply pump of this embodiment, as shown in FIG. 8, the relief valve mechanism 200A supplies fuel through the third hole 1h (vertical hole) as a damper when the internal pressure of the common rail 23 exceeds a set value. It is configured to return to chamber 10c.

That is, in this embodiment, the downstream side of the relief valve mechanism 200A is connected to the damper chamber 10c.

In this case, since the pressure chamber 11 and the relief valve mechanism 200A are not spatially connected, the volume spatially connected to the pressure chamber 11 can be reduced. It is possible to reduce the volume pressurized by the plunger 2 during the discharge stroke, and to increase the efficiency of the discharge amount during high-pressure discharge. By increasing the efficiency of discharge amount, it is possible to reduce the energy required to move up the plunger 2, which can contribute to the improvement of fuel consumption and the reduction of _CO2 .

<Others>
It should be noted that the present invention is not limited to the above examples, and includes various modifications. The above embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the described configurations.

Although the valve 202 is a ball valve in the above embodiment, it may be, for example, a rod-shaped valve body. Also, in the above embodiment, the valve 202 and the valve holder 203 are separate bodies, but they may be integrated.

It is also possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Moreover, it is also possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

In addition, the following aspects may be sufficient as the Example of this invention.
(1). A high pressure fuel supply pump,
a relief seat member on which a relief valve is seated, and a relief valve holder that holds the relief valve, configured to open when the fuel on the discharge side of the pressurization chamber exceeds a set value to release the high-pressure fuel. and a relief spring that biases the relief valve from the downstream side toward the upstream side,
The relief seat member of the relief valve mechanism is
a seat portion on which the relief valve is seated on the inner peripheral side thereof;
a channel portion for flowing the fuel from a high pressure side to a low pressure side,
a press-fitting portion that contacts the member arranged on the outer peripheral side of the relief sheet member when the relief sheet member is press-fitted into the member arranged on the outer peripheral side of the relief sheet member on the upstream side in the flow direction of the fuel;
a groove portion forming a gap between the relief sheet member and a member disposed on the outer peripheral side of the relief sheet member on the downstream side in the fuel flow direction;
A high-pressure fuel supply pump, characterized by comprising:

(2). In the high-pressure fuel supply pump according to (1),
The high-pressure fuel supply pump, wherein the relief sheet member has a projection portion having an outer diameter smaller than that of the press-fit portion formed on the sheet outer peripheral portion of the relief sheet member.

(3). In the high-pressure fuel supply pump according to (1),
The high-pressure fuel supply pump, wherein the groove portion of the relief seat member of the relief valve mechanism is formed of an inclined surface.

(4). In the high-pressure fuel supply pump according to (3),
The inclined surface of the relief sheet member is configured by the inclined surface that is inclined from the inner peripheral side to the outer peripheral side of the relief sheet member when viewed from the downstream side in the fuel flow direction. and high pressure fuel supply pump.

(5). In the high-pressure fuel supply pump according to (1),
A high-pressure fuel supply pump, wherein the relief seat member of the relief valve mechanism is press-fitted into the pump body directly or indirectly via the relief body.

(6). In the high-pressure fuel supply pump according to (1) or (2),
a suction valve disposed on the suction side of the pressurized chamber;
a discharge valve arranged on the discharge side of the pressurizing chamber,
The relief seat member of the relief valve mechanism is configured to return fuel to the pressure chamber or the low-pressure space upstream of the intake valve when the amount of fuel downstream of the discharge valve exceeds a set value. A high-pressure fuel supply pump characterized by:

According to (1) to (6), while the relief sheet is press-fitted and fixed, it is possible to suppress deterioration of the sheet property due to deformation caused by the press-fitting, and to reduce a decrease in discharge efficiency.

Reference Signs List 1 Pump body 2 Plunger 4 Spring 6 Cylinder 7 Seal holder 8 Discharge valve mechanism 9 Pressure pulsation reduction mechanism 10a, 10b Low-pressure fuel suction port 10c Damper chamber 10d Suction passage 10e Fuel passage 10d Suction passage 11 Pressurization chamber 12 Fuel discharge port 13 Plunger seal 14 Damper cover 15 Retainer 28 Fuel pipe 30 Suction valve 50 Suction joint 60 Discharge joint 100 Discharge valve mechanism 200A, 200B Relief valve Mechanism 201 Relief seat 201a Seat portion 201b Fuel passage 201c Protrusion 201d Groove 201e Press-in portion 202 Valve 203 Valve holder 204 Relief spring 205 Relief body 205b Hole 300 Electromagnetic suction valve mechanism

Claims (4)

A high-pressure fuel supply pump having a relief valve mechanism,
The relief valve mechanism is
a relief valve;
and a relief seat member on which the relief valve is seated,
The outer peripheral portion of the relief seat member on the relief valve side has a U-shaped groove portion including an inclined surface that is a side surface of a truncated cone whose diameter is reduced toward the relief valve side ,
an outer peripheral portion of the relief sheet member on the side opposite to the relief valve has a press-fitting portion that is press-fitted into a member arranged on the outer periphery thereof;
A protrusion having an outer diameter larger than the maximum outer diameter of the valve holder and smaller than the press-fitting portion is formed radially on the outer peripheral portion of the relief seat member on the relief valve side.
A high-pressure fuel supply pump characterized by: A high-pressure fuel supply pump according to claim 1,
The press-fit portion is
It is press-fitted into a relief body that houses the relief valve and the relief seat member or a pump body that houses the relief valve mechanism.
A high-pressure fuel supply pump characterized by: A high-pressure fuel supply pump according to claim 1,
Downstream of the relief valve mechanism,
A high-pressure fuel supply pump, characterized by being connected to a pressurizing chamber or a damper chamber. a relief valve;
and a relief seat member on which the relief valve is seated,
A gap is formed between an outer peripheral portion of the relief sheet member on the side of the relief valve and a member arranged on the outer periphery thereof,
The outer peripheral portion of the relief seat member on the relief valve side has a U-shaped groove portion including an inclined surface that is a side surface of a truncated cone whose diameter is reduced toward the relief valve side ,
an outer peripheral portion of the relief sheet member on the side opposite to the relief valve has a press-fitting portion that is press-fitted into a member arranged on the outer periphery thereof;
A protrusion having an outer diameter larger than the maximum outer diameter of the valve holder and smaller than the press-fitting portion is formed radially on the outer peripheral portion of the relief seat member on the relief valve side.
A relief valve mechanism characterized by:

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