JPH0429085Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a fuel injection pump used in a diesel engine, and particularly relates to an improvement in the deflector thereof.

(Prior Art) In a so-called in-line fuel injection pump, a plunger barrel is fixed in the pump body, the plunger is slidably inserted into the plunger barrel, and by reciprocating the plunger, the plunger barrel is moved around the plunger barrel. Fuel is sucked from the formed fuel reservoir chamber into a high pressure chamber in the plunger barrel through a fuel intake/discharge port formed in the plunger barrel, pressurized and sent out, and excess fuel is returned from the fuel intake/discharge port to the fuel reservoir chamber. I have to. When returning fuel from this fuel intake/exhaust port to the fuel reservoir chamber, a high-speed jet hits the pump body that constitutes the fuel reservoir chamber.
Cavitation erosion occurs in the affected area. It is well known that as a means to prevent this cavitation erosion, a deflector is attached to the pump body so that the jet flow is received by the deflector.

Conventionally, commonly used defleters have a flat receiving part facing the fuel intake/exhaust port.
This receiving part was designed to receive the jet, but as the pressure has gradually become higher in recent years, this flat receiving method creates a cavity when the jet leaves the fuel intake/discharge port.
This cavity is crushed by the jet flow that collides with the receiving part, and this causes cavitation erosion in the lead portion of the plunger, which has become noticeable. As a countermeasure against this, for example, as shown in Japanese Patent Application Laid-open No. 128969/1983, a protrusion is provided on the deflector, the protrusion is inserted into a fuel intake/discharge port, and the jet flow exiting from the fuel intake/discharge port is thereby throttled. A plug-in type rectifier in which the rectifier is received by a receiving part of a deflector has been put into practical use, and is known to be effective against the cavitation erosion described above.

(Problem to be solved by the invention) However, in the conventional insertion method, the protrusion and the receiving part are formed integrally with the defleter, and this part is most likely to be worn out by the jet flow, and other parts will be damaged. Although the wear and tear was minimal, the entire deflector had to be replaced, resulting in a lot of waste.
Furthermore, during machining, misalignment between the fuel intake/exhaust port and the deflector insertion hole occurred, resulting in the problem that the deflector could not be attached.

Therefore, this invention aims to improve the structure of the conventional plug-in type deflector and eliminate waste when replacing it.

(Means for Solving the Problems) Therefore, the gist of this invention is to provide a deflector body that is inserted and fixed into a deflector insertion hole formed in the pump body, and a deflector body that is inserted into the deflector body and An internal piece comprising a straight part having a protrusion inserted into the fuel intake/discharge port and a receiving part for receiving the jet flow from the fuel intake/discharge port, and the protrusion is provided eccentrically with respect to the straight part. And, the deflector is constructed from a plug for fixing this internal piece to the deflector main body.

(Function) Therefore, since the protrusion of the internal piece is inserted into the fuel intake/discharge port, the jet coming out of the fuel intake/discharge port is throttled and rectified, and is received by the receiving part of the internal piece, resulting in cavitation erosion. The point of preventing this is the same as before, but since the receiving part of the internal piece that is worn out by the jet is made separate from the deflector body, if the wear becomes large, the deflector body and plug can be replaced without changing the internal piece. In addition, since the protrusion is eccentric to the straight part, even if there is misalignment between the fuel intake/discharge port and the deflector insertion hole, the inner piece will rotate and the protrusion will be removed. can be inserted into the fuel intake/exhaust port, increasing the degree of freedom of removal, thereby achieving the above-mentioned object.

(Example) In FIG. 2, a fuel injection pump has a pump body 1 in which a number of vertical holes 2 corresponding to the number of cylinders are formed, and a plunger barrel 3 is inserted into the vertical holes 2 of the pump body 1. ing. This plunger barrel 3 engages with the pump body 1 at the upper part of the barrel 3, and is pressed by the valve holder 5 with the valve seat body 4 in between. This valve holder 5 is bolted to the upper surface of the pump body 1, has a fuel outlet 6 formed at its tip, and houses a valve spring 7, which pushes the delivery valve 8 against the valve seat body 5. Being seated.

The plunger 9 is slidably inserted into the plunger barrel 3 , the lower end of the plunger 9 engages with a lower spring receiver 10 , and the lower spring receiver 10 is in contact with a plunger guide 11 . The plunger guide 11 is slidably inserted into the vertical hole 2 of the pump body 1. A return spring 13 is elastically mounted between the upper spring receiver 12 and the lower spring receiver 10 engaged with the pump body 1, and the return spring 13 applies a return force to the plunger 9.

Further, a face portion 14 is formed on the plunger 9, and this face portion 14 engages with a control sleeve 15.
is engaged with the control rack 16. Therefore, when this control rack 16 is moved, the plunger 9 rotates via the control sleeve 15, and the circumferential direction between the lead grooves 17a, 17b of the plunger 9 and the fuel intake/discharge ports 20a, 20b of the plunger barrel 3, which will be described later, is rotated. The relative positions of the two can be changed and the injection amount can be adjusted.

A pair of lead grooves 17a, 17b are obliquely formed on the outer periphery near the upper end of the plunger 9, and one end of the lead grooves 17a, 17b and the high pressure chamber 1
A vertical groove 19 is formed to connect the grooves 8 to 8. The high pressure chamber 18 is configured above the plunger 9 and surrounded by the inner surface of the plunger barrel 3.

The fuel intake/exhaust ports 20a, 20b are connected to the plunger barrel 3 in correspondence with the lead grooves 17a, 17b.
When the high pressure chamber 18 is not closed by the plunger 9, the high pressure chamber 18 and the fuel reservoir chamber 21 formed on the outer periphery of the plunger barrel 3 are communicated with each other. This fuel reservoir chamber 21 communicates with a fuel inlet (not shown) formed in the pump body 1. Also,
Deflectors 22a and 22b are mounted on the pump body 1 to face the fuel intake and exhaust ports 20a and 20b, and this deflector 22b (deflector 2
2a also has the same structure. ) is shown in FIG. 1.

In FIG. 1, the deflector 22b is composed of three members: a deflector body 23, an internal piece 24, and a plug 25, which are integrated. The bolt-shaped deflector body 23 is screwed into a deflector insertion hole 26 formed in the pump body 1. This deflector insertion hole 26
is formed such that its central axis is shifted upward from the central axis of the fuel intake/exhaust port 20b. Further, an internal piece insertion hole 27 is formed in the center of the deflector body 23 so as to penetrate from one end to the other end.

As shown in FIG. 3, the inner piece 24 has a stepped straight portion 28 with a projection 29 protruding from one end thereof. The stepped straight portion 28 engages with a step formed in the internal piece insertion hole 27 of the deflector body 23, and the plug 25 screwed into the internal piece insertion hole 28 of the deflector body 1 engages with the stepped portion formed in the internal piece insertion hole 27 of the deflector body 1. It is fastened and fixed to the deflector body 23 from the side. The central axis of the protrusion 29 is eccentric from the central axis of the inner piece 24 by an eccentric amount δ that is approximately equal to the amount of deviation of the deflector insertion hole 26 described above. Therefore, when inserting this inner piece 24, the most protruding portion 29
Even if it is turned down, the protrusion 29 will still be connected to the fuel intake/exhaust port 20b.
It is on the same axis as that and cannot go below that. Further, the tip of the protrusion 29 is formed into a tapered shape, and the tapered tip of the protrusion 29 is inserted into the straight part of the fuel intake/discharge port 20b, and the straight part of the protrusion 29 is inserted into the taper of the fuel intake/discharge port 20b. It is located in a wide area. Above protrusion 2
A receiving portion 30 having an arcuate cross section is formed on the periphery of one end surface of the stepped straight portion 28, and the receiving portion 30 receives the jet flow from the fuel intake/discharge port 20b. This receiving part 3
The surface of 0 is subjected to hard treatment such as soft nitriding treatment.

Note that O-rings 31a and 31b are interposed between the pump body 1 and the deflector body 23, and between the deflector body 23 and the plug 25, respectively.

In the above configuration, when the plunger 9 rises against the return spring 13 in response to the driving force from the engine, the fuel intake/exhaust port 20a is initially opened, so that the fuel in the high pressure chamber 18 is transferred to the fuel intake/exhaust port 20a, 20b to the fuel storage chamber 21,
The pressure of the fuel in the high pressure chamber 18 does not increase, the delivery valve 8 remains closed, and no fuel is injected. Furthermore, when the plunger 9 rises further, the fuel intake/discharge ports 20a and 20b are closed by the outer peripheral surface of the plunger 9, and the high pressure chamber 18 is sealed.
The pressure of the fuel in the high pressure chamber 18 increases, the delivery valve 8 is opened, and fuel is delivered from the fuel outlet 6. When the plunger 9 further rises, the lead grooves 17a and 17b of the plunger 9 cause the fuel intake/discharge port 20 to
a, 20b are opened, and the high pressure chamber 18 and the fuel reservoir chamber 2 are opened.
1 communicate with each other through the vertical groove 19, lead grooves 17a, 17b, and fuel intake/discharge ports 20a, 20b, so that the fuel in the high pressure chamber 18 is discharged into the fuel reservoir chamber 21 through these passages.

When fuel is discharged into this fuel reservoir chamber 21, the fuel intake/discharge ports 20a, 20b and the deflector 22
a, 22b and the protrusion 29, but first it passes between the tapered tip of the protrusion 29 and the straight inlet of the fuel intake/exhaust ports 20a, 20b, so it is gradually narrowed. . Next, protrusion 2
9 straight part and fuel intake/exhaust port 20a,
20b, the jet flow is rectified, and then passes between the straight part of the protrusion 29 and the flared part of the fuel intake/exhaust port, weakening the jet energy and flowing into the fuel reservoir chamber 21.
Go out. Then, the fuel jet is finally directed to deflectors 22a and 22b, as shown by the arrows in FIG.
Since the receiving part 30 is formed in a circular arc shape, the receiving part 30 changes direction and spreads, thereby preventing cavitation from occurring.

When the jets repeatedly collide with the receiving part 30 in this way, the surroundings of the receiving part 30 are gradually damaged, and eventually the receiving part 30 becomes unusable and needs to be replaced. In this case, since only the internal piece 28 is damaged, remove the plug 25 and
The inner piece 28 can be removed, a new inner piece inserted, and the plug 25 screwed together again.

When inserting the internal piece 28, the protrusion 29 of the internal piece 28
0b, and the protrusion 2
9 is eccentric, the internal piece 28 rotates to automatically align the fuel intake/discharge ports 20a, 20b and the protrusion 29. In this case, when the eccentricity δ of the protrusion 29 is made approximately equal to the deviation of the deflector insertion hole 26, the protrusion 29 is located at the lowest position at the fuel intake/discharge port 20 shown in FIG.
The protrusion 29 shown in FIG.
a, 20b, and is located above the position where they are at least coaxial. On the other hand, when the plunger 9 is in the upward stroke, the fuel intake and exhaust ports 20a and 20b
Since fuel is discharged from the fuel intake/discharge port 20
There is a tendency for more water to flow in the upper parts of a and 20b than in the lower parts. Therefore, by positioning the protrusion 29 above the ports 20a and 20b, the proportion of fuel passing through in the circumferential direction becomes equal, and the protrusion 29 comes into contact with the upper surface of the port as shown in FIG. Even if you do, the effect remains the same.

In addition, even in the flat receiving method mentioned as a conventional example, one in which the deflector is shifted upward with respect to the fuel intake and exhaust port has been conventionally used, and when replacing such a conventional deflector, the deflector in the above embodiment is used. Since the protrusion is eccentric, there is an advantage that the deflector in the above embodiment can be used as is and can be made into a plug-in type.

In FIG. 5, another embodiment of the invention is shown, which differs in the shape of the protrusion of the inner piece 28 compared to the previous embodiment. That is, the protrusion 29 is made shorter than that of the previous embodiment and inserted shallowly into the fuel intake/discharge port 20b, and the tapered tip of the protrusion 29 is inserted into the fuel intake/discharge port 20b.
It is arranged at the taper-shaped outlet part of 0b, and the flow is rectified by the tapered part.

(Effects of the invention) As described above, according to this invention, the deflector is composed of a main body, an internal piece inserted into the deflector, and a plug that fixes the deflector, and a protrusion inserted into the fuel intake/discharge port on the internal piece. Since the receiving part for receiving the jet stream is formed, the only part that is consumed is the internal piece, and it is possible to reduce waste when replacing it. Moreover, since the protruding part is eccentrically provided with respect to the straight part, even if there is misalignment between the fuel intake/discharge port and the deflector insertion hole,
The inner piece rotates and the protrusion can be inserted into the fuel intake/exhaust port, increasing the degree of freedom in installation.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the deflector according to an embodiment of this invention attached to a fuel injection pump, Fig. 2 is a sectional view showing the same fuel injection pump, and Fig. 3 is an internal view of the deflector used in the above deflector. FIG. 4 is a sectional view of a deflector in which the inner piece is attached in a different manner, and FIG. 5 is a sectional view of a deflector in another embodiment. 1...Pump body, 3...Plunger barrel,
20a, 20b...Fuel intake/exhaust port, 22a, 2
2b...deflector, 23...deflector body,
24... Internal piece, 25... Plug, 26...
Deflector insertion hole, 29... protrusion, 30... receiving part.

Claims (1)

[Scope of utility model registration request] A fuel intake/discharge port is formed in a plunger barrel fixed to a pump body, and a fuel injection pump deflector is mounted on the pump body facing the fuel intake/discharge port, and is inserted into a deflector insertion hole formed in the pump body. The deflector body is fixed, and the deflector body is fitted into the deflector body.
having a protrusion inserted into the fuel intake/exhaust port,
and an inner piece comprising a straight part formed with a receiving part for receiving the jet flow emitted from the fuel intake/exhaust port, and in which the protrusion is provided eccentrically with respect to the straight part, and for fixing this inner piece to the deflector main body. A fuel injection pump deflector comprising: a plug; and a fuel injection pump deflector.