JP2636515B2 - Fuel injection pump pressure valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure valve of a fuel injection pump for pressurizing fuel sent from a fuel pump and forcing the fuel to a fuel injection valve of an internal combustion engine.

[0002]

2. Description of the Related Art In recent years, with measures against exhaust gas from internal combustion engines, etc.,
The fuel injection pump is pressurized. However, disadvantages such as cavitation erosion in the fuel injection pump may occur as a disadvantage of increasing the pressure. Therefore, there is known a pressure valve of a fuel injection pump in which a pressure valve is mounted on the fuel injection pump so as to prevent the above-described inconvenience from occurring (Japanese Patent Application Laid-Open No. 60-119366).

[0003]

However, as shown in detail in the longitudinal sectional view of FIG. 5, the pressure valve 100 of the conventional fuel injection pump has a valve spring 115 disposed on the outer periphery of the valve body 110 and one end thereof is stepped. Guided by the unit 111. Therefore, the following problem occurs.

(1) The valve spring 115 is large, and the dead volume of the valve chamber 113 is also large. Therefore, the pumping efficiency is deteriorated, which is disadvantageous in increasing the pressure.

(2) The size of the valve chamber 113 is limited, and the valve spring 11 inside the valve chamber 113
5, the thickness of the valve body 110 was small. Accordingly, the pressure difference between the inside and outside of the valve body 110 may cause the valve body 110 to be broken, resulting in poor reliability. Further, a relief valve 118 capable of releasing pressure is housed inside the valve main body 110, but a spring 120 of the relief valve 118,
Since the ball 121 and the like are press-fitted into the valve body 110 with the snubber 122, the valve body 110 in the press-fitted portion may be thin and cracked when the snubber 122 is press-fitted.

Accordingly, an object of the present invention is to solve the above-mentioned problems and improve the pumping efficiency by increasing the dead volume of the valve chamber 113, increase the pressure, and increase the thickness of the valve body 110. By doing so, the object of the present invention is to prevent the valve body 110 from cracking and to provide a highly reliable pressure valve 100 for a fuel injection pump.

[0007]

In order to achieve the above object, the present invention employs the following structure as means for solving the problems. That is, the fuel passage penetrating the inside of the holder member
And a valve chamber which is disposed inside the valve chamber , and moves in the valve chamber in the axial direction, whereby the valve
And <br/> valve body for opening and closing the valve seat portion provided on the fuel inlet side of the chamber, the fuel from the fuel outlet side the valve body
A valve spring disposed in the valve chamber for urging in the inflow side direction and axially penetrating the inside of the valve body.
A fuel relief passage through which the fuel relief passage passes;
From the valve spring end, insert the valve into the valve body.
A snubber inserted oil-tight with the lube body and the snubber.
The snubber is provided on the tip surface in the insertion
A relief valve element for opening and closing the formed small through hole;
The valve body is urged in the direction to close the through hole of the snubber.
In order to achieve this, a relief
A leaf spring, and the snubber is
Press into the valve body from the end of the lube spring side.
Is fixed while maintaining oil tightness with the valve body.
With the above, the valve spring, the snubber,
The relief valve and the relief spring are
Inside the lube chamber,
And said that you are.

[0008]

The valve spring contacts the end of the valve body on the fuel outflow side to urge the valve body toward the fuel inflow side. As a result, the thickness of the valve body can be increased by the amount that the valve spring is not arranged on the outer periphery of the valve body, and cracking of the valve body can be prevented. In addition, the dead volume of the valve chamber is reduced due to the increase in thickness, and the pumping efficiency is increased.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention. The pressure valve 1 of the present embodiment is provided on the fuel outflow side of the fuel injection pump. The pressure valve 1 has a holder member 13 including a valve seat 11 and a valve holder 12 provided on an upper portion of the valve seat 11, a valve body 18 disposed in a valve chamber 16, and a valve body 18 provided on a fuel inflow side. And an energizing valve spring 20.

The pressure valve 1 is fitted into a casing 50 of a fuel injection pump (not shown) and sealed by an O-ring 51. A through passage 15 through which fuel passes is provided inside the holder member 13, and a part of the through passage 15 is a valve chamber 16 having an increased inner diameter. The valve seat 11 is disposed on the fuel inflow side of the valve chamber 16. A valve body 18 is seated on the valve seat 11. A valve spring 20 is provided between the fuel outlet side wall surface of the valve chamber 16 and the fuel outlet side end of the valve body 18.
The valve spring 20 is disposed on the valve body 1.
The valve body 18 is urged toward the valve seat 11 by contacting the end of the fuel outlet 8 on the fuel outflow side. In this embodiment, the valve spring 20 is guided by an upper spring seat 25 and a lower spring seat 26. That is,
Upper spring seat 25 and lower spring seat 26
Are provided with projections 25a and 26a, respectively, and the valve spring 20 is fitted to the outside of the projections 25a and 26a so that the valve spring 20 does not come off.

On the other hand, a pressure adjusting chamber 30 and a passage (fuel relief passage) 31 are provided inside the valve body 18, and a relief valve 22 is provided inside the pressure adjusting chamber 30.
The relief valve 22 has a small hole with a tapered end at the center.
(Small through hole) Snubber 34 having 33 and snubber 3
Ball (relief valve element) that comes into contact with the inner surface of the small hole 33 of No. 4
A spring (relief spring) 37 for urging the ball 35 in the direction of the snubber 34;
And a spring seat 38 that guides the spring. The ball 35, the spring seat 38, and the spring 37 are housed in the valve body 18 by pressing the snubber 34 into the valve body 18.

The operation of the pressure valve 1 of the fuel injection pump configured as described above will be described. As shown by the arrow A, the valve body 18 is pressed to the fuel outflow side based on the pressure of the fuel sent from the fuel inflow side. The valve spring 20 is compressed by this pressure, and the valve body 18 is compressed.
Moves away from the valve seat 11. Then, the valve chamber 16 above the valve seat 11 is opened, and the fuel is released from the valve chamber 16.
Flows into. Due to the inflow of fuel, the pressure in the valve chamber 16 increases. The dead volume of the valve chamber 16 is set to be small by employing a small valve spring 20 and a correspondingly thicker valve body 18. Accordingly, the fuel has a sufficiently high pressure and is efficiently pumped from the through passage 15 to the fuel outflow side as shown by the arrow B. On this occasion,
Since the valve body 18 has a sufficient thickness, it can withstand a pressure difference.

When the pumping of the fuel is completed, the pressure in the valve chamber 16 decreases, the valve body 18 sits on the projection 11a of the valve seat 11, and the valve chamber 16 above the valve seat 11 is closed. Thereafter, when the fuel flows back into the valve chamber 16 above the valve seat 11 due to the reflected wave, and the pressure on the fuel outflow side becomes higher than the fuel inflow side by a predetermined value or more, the relief valve 22 is opened and the pressure is increased. Release to the inflow side. That is, when the fuel flows into the small hole 33 of the snubber 34, the ball 35 overcomes the urging force of the spring 37 and is pushed to the fuel inflow side, and the small hole 33 opens to release the fuel pressure from the passage 31 to the fuel inflow side. . At this time, the valve body 1
Since 8 has a sufficient thickness, it can withstand a pressure difference.

Therefore, in the present embodiment, the valve spring 2
Since 0 is removed from the outer peripheral portion of the valve body 18 and the thickness of the valve body 18 is correspondingly increased, the dead volume of the valve chamber 16 is also reduced. Therefore, the fuel pumping efficiency is high and the pressure can be increased. Further, since the thickness of the valve body 18 is made thicker than the conventional pressure valve,
The valve body 18 does not crack due to a large pressure difference, and the reliability is high.

Next, FIGS. 2 to 4 are longitudinal sectional views showing second to fourth embodiments of the present invention. In these embodiments, the structure of the contact portion between the valve body and the valve spring is different, but the structure of other portions is almost the same as that of the first embodiment.

FIG. 2 shows a second embodiment. In this embodiment, a concave portion 41 having an inner diameter slightly larger than the outer diameter of the valve spring 20 is provided at an end of the valve body 40 on the fuel outflow side.
And the valve spring 20 is fitted. Therefore, since the valve spring 20 can be guided by the valve body 40, there is no need for a lower spring seat for guiding the valve spring 20 downward as in the first embodiment.

FIG. 3 shows a third embodiment. In the present embodiment, the snubber 43 is made longer, and a part of the snubber 43 projects from the end of the valve body 45 on the fuel outflow side. Since the valve spring 20 is fitted on the outer periphery of the snubber 43 to guide the valve spring 20, no spring seat is required.

FIG. 4 shows a fourth embodiment. In the present embodiment, a cutout 46 is formed by cutting out the outer periphery of the valve body 45 on the fuel outflow side. The lower spring seat 47 has a fitting portion 48 fitted on the outer periphery of the cutout portion 46 and a projection 49 on the other end on which the valve spring 20 fits on the outer periphery. Then, a lower spring seat 47 is provided on the outer periphery of the notch 46,
The valve spring 20 is configured to fit around the outer periphery of the valve 9. Therefore, the lower spring seat 47 and the valve body 45 are firmly fitted, and they do not come off from each other, so that the reliability is improved.

Although the embodiments of the present invention have been described above, the present invention is not limited to such embodiments at all, and various improvements can be freely made without departing from the gist of the present invention.

[0020]

As described above in detail, according to the pressure valve of the fuel injection pump of the present invention, since the valve spring does not need to be arranged on the outer periphery of the valve body, the valve body is accordingly moved in the valve chamber. It can be made sufficiently thick. As a result, the dead volume of the valve chamber can be reduced, the pumping efficiency can be improved, and the pressure can be increased.

Further, since the thickness of the valve body can be increased, the valve body does not crack due to the fuel pressure difference, and a highly reliable pressure valve can be provided. Furthermore, the press-fitted portion does not crack when the relief valve component is press-fitted even during manufacture.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a second embodiment of the present invention.

FIG. 3 is a longitudinal sectional view showing a third embodiment of the present invention.

FIG. 4 is a longitudinal sectional view showing a fourth embodiment of the present invention.

FIG. 5 is a longitudinal sectional view showing a pressure valve of a conventional fuel injection pump.

[Description of Signs] 1 ... Pressure valve of fuel injection pump, 11 ... Valve seat, 1
3 ... holder member, 15 ... through passage, 16 ... valve chamber, 18
... valve body, 20 ... valve spring, 22 ... relief valve

Claims (1)

(57) [Claims] 1. A fuel passage penetrating through a holder member.
A valve chamber, which is disposed inside the valve chamber, and extends in the valve chamber in the axial direction.
By moving, it is provided on the fuel inflow side of the valve chamber.
A valve body for opening and closing the valve seat portion, with the fuel outlet side to the fuel inlet side direction said valve body
A valve spring disposed in the valve chamber for energizing the fuel;
And the end of the fuel relief passage on the valve spring side.
And inserted into the valve body while keeping the valve body oiltight.
And a snubber provided on the distal end surface of the snubber in the insertion traveling direction.
A relief valve for opening and closing a small through hole formed in the snubber, and a method for closing the small through hole of the snubber with the relief valve.
Disposed downstream in the fuel relief passage to urge
It includes a relief spring which is, and the snubber, above the end of the valve spring side
The valve body is pressed into the valve body to
Of the valve spring, the snubber, and the relief valve.
The body and the relief spring are located inside the valve chamber.
And a pressure valve for a fuel injection pump, which is arranged at a position in series in the axial direction .