JPH112167A - Two-way delivery valve for fuel injection pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-way delivery valve for a fuel injection pump in which generation of flaw in a ball valve and a seat part of it caused by separation of the ball valve and a spring seat from each other in retraction of fuel can be prevented to eliminate oil-tightness defective, and in which breakage of a two-way delivery valve spring can be prevented. SOLUTION: For supplying fuel flowing around a ball valve 19 to smoothly pass the part of a spring seat 20, not around the spring seat 20, but through a center part of it, a guide passage 31 is formed through the spring seat 20, so fuel flowing along the ball valve 19 can be guided from a second seat part (recessed seat surface) 34 in the ball valve 19 on the spring seat 20 through the guide passage 31 toward a fuel pressure chamber 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure equalizing valve device of a fuel injection pump, and more particularly to a pressure equalizing valve device of a fuel injection pump for adjusting a residual pressure in an injection pipe from a fuel injection pump to a fuel injection nozzle. is there.

[0002]

2. Description of the Related Art A conventional fuel injection pump is provided with an equal-pressure valve device for adjusting a residual pressure in an injection pipe after fuel pressure feeding. For example, JP-A-2-125959 and JP-A-3-92563 are known.

An outline will be given based on FIG. 5 to FIG. FIG.
1 is a cross-sectional view of a main part of a fuel injection pump 1 provided with a conventional equal pressure valve device. The fuel injection pump 1 includes a pump housing 2, a delivery valve holder 3, a delivery valve seat 4, a delivery valve 5, , A constant pressure valve device 6.

The pump housing 2 includes a delivery valve 5
Is formed, and the fuel in the fuel pressure chamber 7 is injected through the delivery valve 5, the fuel outlet 8 of the delivery valve holder 3, and the injection pipe 9 by the pumping action of the fuel injection pump 1. The pressure is fed to the nozzle 10.

[0005] The delivery valve holder 3 houses a delivery valve 5 and a constant pressure valve device 6 in a spring chamber 11 therein, and fixes a delivery valve seat 4.

A delivery valve 5 is seated on the delivery valve seat portion 12 of the delivery valve seat 4, and the delivery valve 5 is seated on the delivery valve seat portion 12 at a predetermined valve opening pressure by the urging force of the delivery valve spring 13. As the plunger 14 of the fuel injection pump 1 rises, the fuel pressure in the fuel pressure chamber 7 rises, and the delivery valve 5 lifts from the delivery valve seat portion 12 against the urging force of the delivery valve spring 13, and the delivery valve 5 The fuel injection passage 10, the spring chamber 11, the fuel outlet 8, and the fuel injection nozzle 10
Pump fuel to

[0007] The delivery valve 5 is equipped with a constant pressure valve device 6 integrally therewith. The constant pressure valve device 6 is accommodated in a constant pressure valve accommodating portion 16 formed in the head thereof.

The constant pressure valve device 6 includes a constant pressure valve holder 17 fitted in a constant pressure valve housing 16, a ball valve 19, a spring seat 20 and a constant pressure valve spring 21 stored in a spring chamber 18 inside the constant pressure valve holder 17. Having.

FIG. 6 is an enlarged sectional view of a main part when the constant pressure valve device 6 is set (when the ball valve 19 is seated).
An orifice 22 communicating with the spring chamber 11 is opened in the constant pressure valve holder 17, and the ball valve 19 is opened to a predetermined position by the urging force of the constant pressure valve spring 21 on the seat portion 23 (first seat portion) of the constant pressure valve holder 17. Seat with pressure. The ball valve 19 is provided with a spring seat 20.
In the concave sheet surface 24 (second sheet portion).

A notch surface 25 is formed on the peripheral surface of the spring seat 20 to provide a gap passage 26 between the inner wall surface of the constant pressure valve holder 17 and the spring seat 20 as well as an orifice 22 and a spring chamber. The area of the communication passage 18 with the fuel pressure chamber 7 side is ensured.

The delivery valve 5 has a suction / return passage 27 (FIG. 5) through which the fuel pressure chamber 7 and the spring chamber 18 can communicate.

In the fuel injection pump 1 and the equal-pressure valve device 6 having the above-described configurations, after the delivery valve 5 is opened, the fuel injection from the fuel injection nozzle 10 ends, the pressure in the injection pipe 9 decreases, and the delivery valve 5 Is driven by the urging force of the delivery valve spring 13.
When sitting at the fuel outlet 8, the reflected pressure from the injection pipe 9
Acts on the ball valve 19 of the isostatic valve device 6 via the spring chamber 11 and the orifice 22,
Is the seat portion 23 against the urging force of the equal pressure valve spring 21.
And a predetermined amount of fuel is supplied from the orifice 22 through the spring chamber 18 and the suction / return passage 27 to the fuel pressure chamber 7.
And the residual pressure in the injection pipe 9 is adjusted to a predetermined range.

FIG. 7 is an enlarged sectional view of a main part of the constant-pressure valve device 6 when the constant-pressure valve device 6 is operated (when the ball valve 19 is lifted).
7 flows back along the spherical surface of the ball valve 19, so that the pressure of this flow is reduced by the upper end surface 28 other than the concave seat surface 24 and the spring seat 2.
As a result, the ball valve 19 and the spring seat 20 are separated from each other as a result of being directly received by the zero concave seat surface 24.

Therefore, when the ball valve 19 is seated on the spring seat 20 at the end of fuel retraction,
There is a problem that the ball valve 19 rides on the upper end surface 28 other than the concave seat surface 24 or the boundary edge portion 29 thereof, and the impact damages the surface of the ball valve 19 (the surface is peeled off). Further, when the ball valve 19 having the flaw is seated on the seat part 23 of the constant pressure valve holder 17, the flaw is transferred to the seat part 23, and there is a problem that the oil tightness of the seat part 23 is deteriorated.

Further, when the fuel is sucked back, the spring seat 20 is separated from the ball valve 19 and lifted, so that the lift amount of the spring seat 20 alone becomes larger than the design study value, and the equal pressure valve spring 21 is damaged. There's a problem.

[0016]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in consideration of the above-mentioned problems. It is an object to provide a device.

Another object of the present invention is to provide a pressure equalizing valve device for a fuel injection pump which can prevent the ball valve and its seat from being damaged due to separation of the ball valve and the spring seat.

Another object of the present invention is to provide a constant-pressure valve device for a fuel injection pump in which a ball valve and a spring seat are not separated when fuel is sucked back.

Another object of the present invention is to provide a constant pressure valve device for a fuel injection pump which can prevent breakage of a constant pressure valve spring.

Another object of the present invention is to provide a constant pressure valve device for a fuel injection pump in which the flow of fuel at the time of fuel suction and return is improved.

It is another object of the present invention to provide a constant-pressure valve device for a fuel injection pump, in which the flow of fuel at the time of fuel suction and return is made smooth.

Another object of the present invention is to provide a constant-pressure valve device for a fuel injection pump in which the ratio of the pressure of fuel along the ball valve during the suction and return of the fuel directly acting on the spring seat is reduced.

[0023]

That is, the present invention is to provide a fuel supply system in which fuel flowing around a ball valve can smoothly pass through a spring seat portion. The first invention focuses on allowing fuel to pass through the center of the fuel injection chamber, and the first invention is a pressure equalizing valve device of a fuel injection pump for pumping fuel from a fuel pressure chamber to a fuel injection nozzle via an injection pipe. A ball valve that lifts the fuel in the injection pipe back toward the fuel pressure chamber by lifting from the first seat portion on the injection pipe side, and a second valve that seats the ball valve. A spring seat having a seat portion formed therein, and a constant pressure valve spring for urging the ball valve toward the first seat portion via the spring seat. And a guide passage is formed through the spring seat, and from the second seat portion of the ball valve in the spring seat, through the guide passage toward the fuel pressure chamber, along the ball valve. A pressure equalizing valve device for a fuel injection pump, characterized in that flowing fuel can be guided.

The guide flow path may be constituted by a single through hole penetrating from the ball valve side to the fuel pressure chamber side, and an inclined groove communicating with the through hole.

A plurality of the inclined grooves may be formed, and the second sheet portion may be formed between the inclined grooves.

A second invention is a pressure equalizing valve device of a fuel injection pump for pumping fuel from a fuel pressure chamber to a fuel injection nozzle via an injection pipe, wherein the valve is lifted from a first seat portion on the injection pipe side. A ball valve capable of sucking back the fuel in the injection pipe in the direction of the fuel pressure chamber, a spring seat having a second seat portion on which the ball valve is seated, and the ball through the spring seat. A constant pressure valve spring for urging the valve in the direction of the first seat portion, and the fuel flowing along the surface of the ball valve is supplied to the inside of the spring seat and the inside of the constant pressure valve spring. A constant pressure valve device for a fuel injection pump, characterized in that a guide passage that can be guided is formed in the spring seat.

In the pressure equalizing valve device for a fuel injection pump according to the present invention, the seat shape of the spring seat is such that fuel flowing around the ball valve and flowing toward the spring seat can smoothly pass through the fuel pressure chamber. That is, the guide channel was formed in the spring seat. For example, a through hole was machined in the center of the spring seat, and an inclined groove for guiding the fuel sucked back into the through hole was machined around the through hole. Therefore, the fuel flowing along the peripheral surface of the ball valve does not flow from the upper portion of the spring seat to the outer peripheral portion as in the related art, but flows along the flow line of the spring seat (for example, the inclined groove and the through hole). ), And the degree of pressure exerted on the upper end of the spring seat can be extremely reduced. Therefore, while preventing the spring seat from separating from the ball valve,
Fuel can be sucked back.

Thus, the above-mentioned problems caused by the separation of the ball valve and the spring seat are solved.
Oil tightness can be maintained, and breakage of the constant pressure valve spring due to excessive lift of the spring seat does not occur.

[0029]

FIG. 1 is a perspective view of a fuel injection pump according to an embodiment of the present invention; FIG. However, the same parts as those in FIGS. 5 to 7 are denoted by the same reference numerals, and detailed description thereof will be omitted. FIG.
FIG. 3 is an enlarged sectional view of a main part of the constant pressure valve device 30 and the delivery valve 5. In the constant pressure valve device 30, the processing form of the spring seat 20 is changed from the conventional one, and the other structure is the constant pressure valve device 6. Is virtually the same.

FIG. 2 is an enlarged perspective view of the spring seat 20, and FIG. 3 is an enlarged sectional view of a main part when the constant pressure valve device 30 is set (when the ball valve 19 is seated). From the side facing the valve 19 (the side facing the seat portion 23), the spring chamber 1
A guide passage 31 is formed so as to communicate with the fuel pressure chamber 7 of the fuel cell 8.

The guide flow path 31 is composed of an inclined groove 32 expanding toward the ball valve 19 and a central through hole 33 communicating with the inclined groove 32. An intervening concave sheet surface 34 (second sheet portion) is formed.

Although four inclined grooves 32 are formed in the illustrated example, the inclined grooves 32 are formed so that fuel from the orifice 22 and the ball valve 19 can be smoothly guided to the through holes 33 along the streamlines. The number, inclination angle, width, etc.
Design this arbitrarily.

The through-hole 33 is only required to be able to suck back the fuel as linearly as possible from the orifice 22 to the fuel pressure chamber 7 side of the spring chamber 18 following the inclined groove 32.
The pore size is arbitrary.

The concave seat surface 34 allows the ball valve 19 to be seated between the inclined grooves 32, and may be any as long as it can transmit the urging force of the constant pressure valve spring 21 to the ball valve 19.

In the pressure equalizing valve device 30 having such a configuration,
FIG. 4 is an enlarged cross-sectional view of a main part when the equal-pressure valve device 30 is operated (when the ball valve 19 is lifted), and acts on the ball valve 19 as shown in FIG. The fuel lifted from around flows around the ball valve 19 and
The spring seat 20 is guided to the center of the spring seat 20 along the inclined groove 32, and passes through the through hole 33.
8 Further, it reaches the suction / return passage 27.

Therefore, the fuel from the ball valve 19 to the spring seat 20 can flow to the spring chamber 18 and the suction / return passage 27 with little effect on the spring seat 20. There is no separation. Thus, the ball valve 19 and the spring seat 20
This can effectively suppress the occurrence of scratches on the ball valve 19 due to the separation and the scratches on the seat portion 23 of the constant-pressure valve holder 17, and can eliminate poor oil-tightness.

Further, since the spring seat 20 does not lift from the ball valve 19, the constant pressure valve spring 21 also performs a compression action as designed, and the constant pressure valve spring 2
1 can be avoided.

Further, the fuel is not supplied to the gap passage 26 and the notch surface 25 on the outer peripheral portion of the spring seat 20 whose flow path is easily narrowed as in the conventional constant pressure valve device 6, but to the through hole 33 in the central portion thereof. Since the fluid passes through the inside of the constant pressure valve spring 21, the fluid pressure is reduced, and the lift amount of the ball valve 19 is reduced in combination with the fact that the ball valve 19 and the spring seat 20 are difficult to be separated, and the responsiveness of suction and retraction is reduced Improved and able to accommodate high pressure and high speed injection pumps. Moreover, ball valve 1
Since the lift stroke of the spring 9 and the spring seat 20 is reduced, the possibility of wear and breakage due to collision acceleration when the ball valve 19 is seated on the seat 23 is also reduced.

In the above-described embodiment, the guide channel 31 is constituted by the inclined groove 32 and the through hole 33.
As described above, the flow of the fuel can be smoothly guided to the inside of the spring seat 20 and the inside of the equal pressure valve spring 21, that is, the flowing fuel exerts a force on the spring seat 20. If there is no such thing, for example, there is no bend in the cross section,
The guide channel may have any shape.

[0040]

As described above, according to the present invention, a guide channel is formed in a spring seat by an inclined groove and a through hole, and fuel is guided along the surface of a ball valve and inside the spring seat. Since the flow is controlled so that the fuel pressure is not applied to the spring seat as much as possible, the separation of the ball valve and the spring seat does not occur, and the reliability and reliability of the equal pressure valve device can be secured.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a main part of a constant pressure valve device 30 and a delivery valve 5 of a fuel injection pump according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective view of the spring seat 20 in which a guide channel 31 is formed.

FIG. 3 is an enlarged sectional view of a main part when the constant pressure valve device 30 is set (when the ball valve 19 is seated).

FIG. 4 shows a state in which the constant pressure valve device 30 is operated (the ball valve 1).
9 is an enlarged cross-sectional view of a main part at the time of a lift of No. 9).

FIG. 5 shows a fuel injection pump 1 equipped with a conventional equal pressure valve device 6.
It is principal part sectional drawing of.

FIG. 6 shows a state in which the constant pressure valve device 6 is set (the ball valve 1).
9 is an enlarged cross-sectional view of a main part at the time of sitting).

FIG. 7 shows a state in which the constant pressure valve device 6 is operated (the ball valve 19).
FIG. 4 is an enlarged cross-sectional view of a main part at the time of a lift).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Fuel injection pump (FIG. 5) 2 Pump housing 3 Delivery valve holder 4 Delivery valve seat 5 Delivery valve 6 Equal-pressure valve device of fuel injection pump 1 (FIGS. 5 to 7) 7 Fuel pressure chamber 8 Fuel outlet 9 Injection pipe 10 Fuel Injection nozzle 11 Spring chamber 12 Delivery valve seat part of delivery valve seat 4 13 Delivery valve spring 14 Plunger 15 Fuel discharge passage 16 Constant pressure valve housing 17 Constant pressure valve holder 18 Spring chamber 19 Ball valve 20 Spring seat 21 Constant pressure valve spring 22 Orifice 23 Seat portion (first seat portion) 24 of constant pressure valve holder 17 Concave seat surface 24 of spring seat 20 (second seat portion)
25 Notch surface 26 Gap passage 27 Suction / return passage 28 Upper end surface of spring seat 20 29 Boundary edge of spring seat 20 30 Isobaric valve device of fuel injection pump 1 (embodiment, FIGS. 1 to 4) 31 guide flow path of spring seat 20 32 inclined groove of spring seat 20 33 through hole of spring seat 20 34 concave seat surface of spring seat 20 (second seat portion)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeshi Ichinose 3-13-26 Yayumicho, Higashimatsuyama-shi, Saitama Inside of Zexel Higashimatsuyama Plant

Claims (4)

[Claims] 1. A pressure equalizing valve device of a fuel injection pump for pumping fuel from a fuel pressure chamber to a fuel injection nozzle via an injection pipe, wherein the injection is performed by lifting from a first seat portion on the injection pipe side. A ball valve capable of sucking back the fuel in the pipe toward the fuel pressure chamber, a spring seat having a second seat portion on which the ball valve is seated, and the ball valve being connected to the ball valve through the spring seat. And a constant-pressure valve spring biasing in the direction of the seat portion, wherein a guide passage is formed through the spring seat, and the guide passage is formed from the second seat portion of the ball valve in the spring seat. A fuel injection pump or the like characterized in that fuel flowing along the ball valve can be guided in the direction of the fuel pressure chamber through a flow path. The valve device. 2. The method according to claim 1, wherein the guide flow path comprises a single through hole penetrating from the ball valve side to the fuel pressure chamber side, and an inclined groove communicating with the through hole. The equal-pressure valve device for a fuel injection pump according to claim 1, wherein 3. The constant-pressure valve device for a fuel injection pump according to claim 2, wherein a plurality of the inclined grooves are formed, and the second seat portion is formed between the inclined grooves. 4. An equal-pressure valve device of a fuel injection pump for pumping fuel from a fuel pressure chamber to a fuel injection nozzle via an injection pipe, wherein the injection is performed by lifting from a first seat portion on the side of the injection pipe. A ball valve capable of sucking back the fuel in the pipe in the direction of the fuel pressure chamber, a spring seat having a second seat portion on which the ball valve is seated, and the ball valve being connected to the ball valve via the spring seat. And a constant pressure valve spring that urges in the direction of the seat portion, and guides the fuel flowing along the surface of the ball valve to the inside of the spring seat and the inside of the constant pressure valve spring. A constant pressure valve device for a fuel injection pump, wherein a flow path is formed in the spring seat.