JPH0332782Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel injection pump, particularly a fuel injection pump of a type in which the lower part of the plunger is forcibly lubricated with lubricating oil.

[Conventional technology and its problems]

In a diesel engine fuel injection pump, the sliding surface between the inner circumferential surface of the barrel and the outer circumferential surface of the plunger inserted therein is lubricated with leaked fuel.
The leaked fuel used for lubrication is stored in an annular groove formed on the inner peripheral surface of the barrel, and is returned to the fuel storage chamber between the barrel and the housing via the plunger chamber and fuel supply/discharge hole by a leak return system.

However, with such a configuration, it is difficult to return all the leaked fuel, and the leaked fuel flows along the sliding surface below the annular groove and flows into the plunger spring chamber and further into the crank chamber, diluting the lubricating oil in the crank chamber. cannot be prevented from doing so.

As a countermeasure to this problem, conventionally, in Japanese Utility Model Application No. 53-16718 and Japanese Utility Model Publication No. 57-13405, an annular lubricating oil groove is formed on the inner peripheral surface of the barrel below the annular groove, while lubricating oil is formed on the side wall of the barrel. An oil inlet is formed, and pressurized lubricating oil is sent from this lubricating oil inlet to an annular lubricating oil groove through a vertical passage in the wall of the barrel, thereby forming an oil film to prevent leakage fuel from flowing down. A forced lubrication mechanism has been proposed that not only stops the plunger but also lubricates the lower part of the plunger.

However, when ultra-low quality oil is used as fuel in a marine engine, for example, the viscosity of the fuel increases due to the temperature drop when the engine is stopped, and the solidification of the fuel makes it impossible to provide sufficient lubrication when the engine is started.
For this purpose, it is effective to increase the sliding clearance between the plunger and the barrel, but on the other hand, the oil tightness becomes poor, and the amount of fuel leaking downward from the annular groove for returning leakage increases. If the distance in the axial direction of the lubricating oil groove is large, the upward pushing force from the annular lubricating oil groove is insufficient, making it impossible to recover leaked fuel.

Therefore, in Utility Application No. 60-75701, the present applicant formed an eccentric annular groove for secondary return on the inner peripheral surface of the barrel between the annular groove for returning leaked fuel and the annular lubricating oil groove, while also forming an eccentric annular groove for barrel positioning. An outflow port is bored using a locking bolt, a notch is formed on the outer periphery of the barrel so as to obtain a reservoir between the tip of the bolt, and this notch is connected to the eccentric for secondary return. We proposed a system in which the annular grooves were communicated through a return passage formed in the barrel wall. According to this, it becomes possible to efficiently recover the mixed oil of leaked fuel and lubricating oil by the pushing force of the lubricating oil.

However, when trying to actually apply this idea, the lubricating oil inlet and the reservoir/outlet are opened directly on the outer periphery of the barrel at approximately the same position in the axial direction and 180 degrees displaced in the circumferential direction. Therefore, there is a risk that some of the lubricating oil that is press-filled from the lubricating oil inlet may travel through the gap between the barrel and housing and reach the reservoir chamber without being used to lubricate the plunger, and be discharged from the outflow hole. Ta.

[Means for solving problems]

This invention was devised through research to solve the above-mentioned problems, and its purpose is to maintain good oil tightness between the housing and the barrel in the area corresponding to the lubricating oil inlet. The object of the present invention is to provide a fuel injection pump of this type that can effectively lubricate the lower part of the plunger with lubricating oil, prevent leaked fuel from flowing into the crank chamber, and recover leaked fuel and lubricating oil.

To achieve this objective, the present invention has a special adapter inserted into at least the lubricating oil inlet, that is, a plunger is inserted into the barrel in an axially movable and rotatable manner, and the plunger is inserted into the inner peripheral surface of the barrel. A plurality of annular grooves are formed at intervals from each other, and a lubricating oil supply passage is formed in the barrel wall with one end leading to the lowest annular groove to forcibly lubricate the lower sliding contact area between the plunger and the barrel. In this fuel injection pump, a lubricating oil inlet having a diameter that includes the aperture of the supply passage in the side wall of the housing corresponding to the opening of the lubricating oil supply passage on the outer circumferential surface of the barrel is provided; Insert into the lubricating oil inlet an adapter that includes a main body with a curvature end face corresponding to the outer peripheral surface of the barrel and an injection hole in the center, and an elastic gasket with a hole in the center that matches the injection hole. It is characterized by the fact that it has been worn.

In addition, the present invention more preferably applies the above configuration to an outlet located at a position displaced by 180 degrees from this.

〔Example〕

1 to 3 show an embodiment of the fuel injection pump according to the present invention, and FIGS. 4 to 7 show the adapter alone.

1 is a housing, 2 is a barrel fitted into the housing 1, 3 is a plunger inserted into the barrel 2 so as to be movable in the axial direction and rotatable in the circumferential direction,
A lead 26 is formed on the head, and the barrel 2 corresponding to the lead 26 has fuel supply and discharge holes 28 and 2 that communicate with an annular fuel storage chamber 27 formed between the inner walls of the housing 1.
9 is installed through it. Further, a plunger chamber (fuel compression chamber) 30 is provided above the head.

Reference numeral 4 designates an injection amount control sleeve, which is rotatably fitted around the outer periphery of the barrel 2, has a pinion 31 formed on its outer periphery, and meshes with a control rack 32 slidably inserted into the housing 1. A slit 34 that engages with the face portion 33 of the plunger 3 is provided in the lower part of the injection amount control sleeve 4.

A spring chamber 35 is provided in the housing corresponding to the lower part of the control rack 32 via a step 36, and is located between a spring seat 37 that abuts the step 36 and a plunger guide (not shown) fitted to the housing mouth end. , a plunger spring 38 is interposed via a spring seat.

Numerals 5a, 5b, and 5c are a plurality of annular grooves (three in this embodiment) formed on the inner peripheral surface of the barrel below the lead 26 at predetermined intervals in the axial direction.

First, the uppermost annular groove 5a is for primary leak fuel return, and the plunger chamber 30 is connected to the primary return passage 40 bored in the plunger 3 or barrel 2.
It also communicates with the fuel storage chamber 27.

The intermediate annular groove 5b is for collecting the mixed oil of lubricating oil and leaked fuel, as will be described later.
A recovery passage 42 is formed eccentrically with respect to the barrel hole center and opens in a notch 41 on the outer peripheral surface of the barrel at the deepest part of the groove.

The lowest annular groove 5c is for lubricating oil supply, and communicates with a supply passage 43 bored in the barrel wall at a position 180 degrees out of phase with the recovery passage 42 in the circumferential direction. is closed by a blind plug 44. Further, the upper end of the supply passage 43 is opened in the outer peripheral surface of the barrel at approximately the same position in the axial direction as the recovery passage 42 .

Reference numeral 6 denotes a lubricating oil inlet, which is provided through the side wall of the housing so as to include the opening of the supply passage 43 in its diameter, and a female thread 45 is formed in the rear half of the lubricating oil inlet 6 in the axial direction. ing.

7 is an outlet for recovering mixed oil of lubricating oil and leaked fuel (hereinafter referred to as mixed oil outlet);
It extends through the side wall of the housing so as to include the recovery passage 42 and the notch 41 in its diameter, and a female thread 46 is formed in the rear half of the mixed oil outlet 7 in the axial direction.

8 and 9 are adapters featured in this invention,
In this embodiment, they are inserted into the lubricating oil inlet 6 and the mixed oil outlet 7, respectively. As shown in FIGS. 1 to 5, the lubricating oil inlet adapter 8 has a curved end surface 11 corresponding to the outer peripheral surface of the barrel 2, and the supply passage 4 is located at the center of this curved end surface 11.
The main body 1 has an injection hole 12 that communicates with the opening of No. 3.
0, and a gasket 13 made of elastic material such as rubber, which is integrated with the curved end surface 11 by adhesive or the like,
The gasket 13 has a hole 14 corresponding to the injection hole 12.
is formed. A seal ring 15 is provided on the outer periphery of the main body 10 and is in contact with the inner wall of the lubricating oil inlet 6.
A ring groove 16 is formed for attaching the ring.

The adapter 9 for the mixed oil outlet is attached to the barrel 2 as shown in FIGS. 1 to 3 and FIGS. 6 and 7.
It has a curvature end surface 11' corresponding to the outer peripheral surface of the collection passage 4, and the collection passage 4 is located at the center of this curvature end surface 11'.
The main body 10' is provided with an outflow hole 12' that communicates with the opening of No. 2, and a gasket 13' made of elastic material such as rubber is integrated with the curved end surface 11' by adhesive or the like. In this respect, it is similar to the adapter 8 for the lubricating oil inlet, but in this adapter 9, the notch 4 of the barrel 2 is located at the center of the end surface of the main body.
A protrusion 17 that is loosely inserted into the gasket 1 is protruded from the gasket 1 .
A hole 14' corresponding to the protrusion 17 is formed in 3'. A ring groove 16' is formed on the outer periphery of the main body 10' for mounting a seal ring 15' that contacts the inner wall of the spout 7.

18 is an auxiliary adapter for pressing the lubricating oil injection adapter 8 against the barrel outer periphery with a required pressure; 19 is an auxiliary adapter for pressing the mixed oil outflow adapter 9 against the barrel outer periphery with a required pressure; A through hole 20 aligned with the injection hole 12 and a passage 2 aligned with the outlet hole 12' at their centers, respectively.
0' is bored, the passage 20 is connected to a lubricating oil supply system via a pipe (not shown), and the passage 20' is connected to an oil tank via a pipe (not shown).

Each of the auxiliary adapters 18 and 19 has male threads 47 and 4 screwed into female threads 45 and 46 formed at the lubricating oil inlet 6 and mixed oil outlet 7 on the outer periphery.
8 is formed. Intermediate gaskets 21 and 22 are interposed between the front end surfaces of the auxiliary adapters 18 and 19 and the rear end surfaces of the adapters 8 and 9.

In the embodiment, an O-ring 22 for maintaining oil tightness between the outer periphery of the barrel and the inner periphery of the housing is connected to the lubricating oil inlet 6.
and the mixed oil outlet 7, so that the adapter body 10, 10'
Notches 24, 24' forming part of the O-ring mounting groove 23 of the housing 1 are formed in the housing 1. Of course, if the O-ring is provided at a different location, the cutouts 24, 24' are not necessary.

In this embodiment, since the adapter 9 also serves as a means for positioning the barrel, a protrusion 1 is provided on the main body 10'.
7, but if the barrel positioning bolt is provided separately, the same configuration as adapter 8 can be adopted.

[Effect of the embodiment]

The usage and operation of the above configuration will be explained.

When assembling the pump, the adapters 8 and 9 are inserted into the lubricating oil inlet 6 and mixed oil outlet 7, respectively, and the auxiliary adapters 18 and 19 are placed behind them via intermediate gaskets 21 and 21'. 47 and 48 are screwed into the female threads 45 and 46 in the lubricating oil inlet 6 and mixed oil outlet 7. The tightening force caused by this tightens the curved end surfaces 11 and 1 of the adapters 8 and 9.
Gasket 13, 1 of the same shape fixed to 1'
3' is compressed and comes into close contact with the outer peripheral surface of the barrel, and the required range of the outer periphery of the opening of the supply passage 43 and the opening of the recovery passage 42 is made oil-tight. Furthermore, since the gaskets 8 and 9 are elastic, the barrel will not be damaged by vibration or the like. And when necessary, the auxiliary adapter 18,
19 can be removed for easy inspection and replacement.

The plunger 3 is rotated by a control rack 32 via the injection amount control sleeve 4, the amount of fuel injected in the plunger chamber is set by the reed 26 and the fuel discharge hole 29, and the plunger 3 is rotated along the axis by a cam (not shown) via the plunger guide. direction, compressing the fuel in the plunger chamber and forcefully delivering it to the injection nozzle via the delivery valve and conduit.

As the plunger 3 operates, the fuel is transferred to the barrel 2.
It flows downward between the inner circumferential surface of the plunger 3 and the outer circumferential surface of the plunger 3. Most of this leaked fuel accumulates in the annular groove 5a at the top of the inner peripheral surface of the barrel, and is stored in the primary return passage 4.
0 to the fuel system. Then, a part leaks further downward and flows into the intermediate annular groove 5b. This leaked fuel ascends the recovery passage 42, is fed into the notch 41, passes through the outlet hole 12'20' of the adapter 9 and the auxiliary adapter 19, and is recovered into the oil tank.

On the other hand, the lubricating oil sent from the lubricating oil supply system is supplied to the auxiliary adapter 18 and the injection hole 2 at the center of the adapter 8.
0 and 12 into the supply passage 43, and is supplied from this supply passage 43 through the annular groove 5c between the inner peripheral surface of the barrel and the outer peripheral surface of the plunger, forming an oil film, which forcibly lubricates the lower part of the plunger, and then It flows down through the spring chamber 38. Since this lubricating oil is of the same quality as the lubricating oil used in the crank chamber, problems due to dilution do not occur.

Further, the oil film also flows upward, thereby pushing up the leaked fuel that is not collected in the intermediate annular groove 5b into the intermediate annular groove 5b. This mixed oil of leaked fuel and lubricating oil passes through the outflow holes 12', 20' of the adapter 9 and the auxiliary adapter 19, and is collected in the oil tanks.

As mentioned above, the lubricating oil supply port 6 and the mixed oil outlet 7
The adapter 8 has a curved end surface 11 that matches the outer peripheral surface of the barrel as described above, and the gasket 13 of the same shape fixed thereto is located on the same circumference as the lubricating oil supply passage 43. Opening hole and injection hole 12
There is an oil-tight seal between the barrel and housing. Therefore, the entire amount of lubricating oil is reliably supplied to the lubricating oil supply passage 43, and it is possible to effectively lubricate the lower part of the plunger and push up leaked fuel. In addition, since the barrel and housing corresponding to the mixed oil outlet 7 are also oil-tightly sealed by the adapter 9, the entire amount of mixed oil is efficiently recovered, and there is no risk of the mixed oil leaking into the injection amount control mechanism. disappears.

The present inventor proposed a method in which a flat seat is formed on the outer periphery of the barrel and a screw-in adapter is abutted against this as a measure against oil leakage between the barrel and the housing at the lubricating oil supply port and mixed oil outlet. Also considered. However, with this method, it is difficult to secure the space necessary to form the O-ring groove under the lubricating oil supply port and mixed oil outlet, and forming the seat in the barrel increases the machining process, leading to increased costs. be. According to the present invention, such problems can be avoided.

[Effect of idea]

According to the present invention described above, a plurality of annular grooves 5a, 5b, 5c are formed at intervals in the axial direction on the inner peripheral surface of the barrel 2 into which the plunger 3 is movably and rotatably inserted. On the other hand, in a fuel injection pump in which a lubricating oil supply passage 43 is formed in the barrel wall, one end of which communicates with the lowest annular groove 5c, the lower sliding contact area of the plunger 3 and the barrel 2 is forcibly lubricated. Oil supply passage 43
A lubricating oil inlet 6 having a diameter that includes the aperture of the supply passage 43 is provided in the side wall of the housing corresponding to the opening on the outer circumferential surface of the barrel. A main body 1 having a curvature end surface 11 corresponding to the surface and having an injection hole 12 in the center.
0 and an elastic gasket 13 having a hole 14 in the center that matches the injection hole 12.
is inserted, the elastic gasket 13 comes into close contact with the outer peripheral surface of the barrel via the curved end surface 11 of the main body 10, and the gasket 13 closes around the opening of the supply passage 43 and the injection hole 1.
There is an oil-tight seal between the barrel and housing around 2. Therefore, the entire amount of lubricating oil is reliably injected into the supply passage 43 without leaking between the barrel outer circumferential surface and the housing inner circumferential surface, and is sent between the barrel and the plunger outer circumferential surface through the annular groove 5c, thereby lubricating the lower part of the plunger. It is also possible to effectively push up leaked fuel from above. Since the injected lubricating oil does not circulate around the outer circumference of the barrel from the opening of the supply passage 43, a mixed oil flow of leaking fuel from above and pushing up lubricating oil flows to a position 180 degrees displaced in the circumferential direction from the injection site. An excellent effect can be obtained in that it can be used effectively even when an exit is provided.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional side view showing an embodiment of the fuel injection pump according to the present invention, Fig. 2 is a partially enlarged view of Fig. 1, Fig. 3 is a partial cross-sectional view of Fig. 1, and Fig. 4 5 is a side view of the adapter for lubricating oil inlet, FIG. 5 is a front view thereof, FIG. 6 is a side view of the adapter for mixed oil outlet, and FIG. 7 is a front view thereof. DESCRIPTION OF SYMBOLS 1... Housing, 2... Barrel, 3... Plunger, 5a, 5b, 5c... Annular groove, 6... Lubricating oil inlet, 8... Adapter, 10... Main body, 11... Curved end surface, 12... Injection hole, 13... Gasket, 14...
Hole, 43...supply passage.

Claims (1)

[Scope of utility model registration request] A plurality of annular grooves 5a, 5b, 5c are formed at intervals in the axial direction on the inner circumferential surface of the barrel 2 into which the plunger 3 is movably and rotatably inserted. In a fuel injection pump in which a lubricating oil supply passage 43 communicating with the lower annular groove 5c is formed to forcibly lubricate the lower sliding contact area between the plunger 3 and the barrel 2, the barrel outer peripheral surface of the lubricating oil supply passage 43 The supply passage 4 is provided in the side wall of the housing corresponding to the opening site for the supply passage 4.
A lubricating oil inlet 6 with a diameter that includes the opening of No. 3 in its diameter.
The lubricating oil inlet 6 has a curvature end surface 11 corresponding to the outer peripheral surface of the barrel, and an injection hole 12 in the center.
an elastic gasket 13 having a hole 14 in the center that matches the injection hole 12;
A fuel injection pump characterized in that an adapter 8 is inserted therein.