JPS5828421B2 - Pump Souch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel injection pump device, and more particularly, a plunger that can reciprocate in a guide hole, a pump chamber composed of the guide hole and an inner end surface of the plunger, and a fuel injection pump device. a fuel outlet, a spill port formed in the wall of the conduit, configured on the plunger and communicating with the spill port at the end of the inward movement of the plunger so that fuel remaining in the pump chamber passes through the spill port; a drain groove that allows fuel to escape through and terminate the flow of fuel through the fuel outlet.

Conventionally, a plunger that can reciprocate in a guide hole, a pump chamber composed of the guide hole and an inner end surface of the plunger, a fuel outlet from the pump chamber, and a spill port formed in the wall of the guide hole, a fuel outlet configured on the plunger and in communication with a spill port at the end of inward movement of the plunger to allow fuel remaining in the pump chamber to escape through the spill port to direct the flow of fuel through the fuel outlet; Fuel injection pump devices are known that have a discharge groove that ends.

However, this conventional fuel injection pump device has a drawback that the plunger is subjected to side pressure during operation because a discharge groove is formed on one side of the plunger.

Also, some of the fuel flows out between the plunger and the guide hole,
This leaked fuel may enter the chamber that houses the plunger driving cam and follower and dilute the lubricating oil in the chamber.

For this reason, there is conventionally known a fuel injection pump device that has a circumferential groove formed on the plunger below the discharge groove of the plunger to collect fuel leaking between the plunger and the guide hole. .

However, this conventional fuel injection pump device has the disadvantage that fuel contaminants such as metal abrasion powder, dirt, dust, etc. accumulate in the shield groove, and the outer circumferential surface of the plunger and the inner circumferential surface of the guide hole are damaged by this contaminant. there were.

The present invention was made in order to eliminate the drawbacks of the conventional fuel injection pump device, and an object of the present invention is to provide a fuel injection pump that allows contaminants in the shielding groove to flow out to the outside.

The present invention provides a plunger that can reciprocate in a guide hole, a pump chamber composed of the guide hole and an inner end surface of the plunger, a fuel outlet from the pump chamber, and a spill port formed on the wall of the guide hole. and a flow of fuel through the fuel outlet configured in the plunger and in conjunction with a spill port at the end of inward movement of the plunger to allow fuel remaining in the pump chamber to escape through the spill port. in a fuel injection pump device, the fuel injection pump device has a discharge groove formed on the plunger at a position below the discharge groove of the plunger to collect fuel leaking between the plunger and the guide hole. a slanted groove formed on the plunger at a position opposite to the discharge groove and communicating with the slanted groove, and an opening formed in the wall of the guide hole; is characterized in that it communicates with the opening so as to allow fuel collected in the barrier to escape through the opening upon inward movement of the plunger.

The present invention will be explained below with reference to embodiments shown in the drawings.

In FIG. 1, a barrel 11 is fixed to a hollow member 10, which holds a plunger 12 in an axial guide hole.

At the inner end of the guide hole, an outlet 13 is formed which is provided with a discharge check valve 14 which is pressed downward in the figure by a spring, and which communicates with an injection nozzle associated with the engine cylinder. Ru.

Furthermore, intermediate between the ends of the guide hole, the barrel 11 is provided with a radial spill port 15, which is connected to the hollow member 1.
0, and fuel is sent to this annular recess 16 from a supply pump (not shown).

The spill port 15 is connected to the plunger 12 when the plunger 12 is at its outermost limit position (lower limit position in the figure).
It is formed in a position that is not covered by the outer peripheral surface of No. 2.

Therefore, when the plunger 12 is in this state, fuel will enter the pump chamber from the annular recess 16.

During the inward movement of the plunger 12 (in the upward movement in the figure), the spill port 15 is blocked by the plunger 12, and the fuel in the guide hole passes through the check valve 14 to the upper outlet 1.
3 to the engine cylinder.

A spiral discharge groove 17 is formed on the outer peripheral surface of the plunger 12 .

This discharge groove 17 communicates with a pump chamber formed by the inner end (upper end) of the plunger 12 and the guide hole through a passage (not shown) formed in the plunger 12.

When the plunger 12 moves inward (upward movement in the figure),
Spill port 15 is initially blocked by the end of plunger 12, and as plunger 12 moves further inwardly (upwards), fuel is delivered to the engine as described above.

During the upward movement of the plunger 12, until the discharge groove 17 of the plunger 12 aligns with the spill port 15 and the spill port 15 opens into the discharge groove 17, the fuel passes through the check valve 14 and the outlet 13 to the engine. sent to.

On the other hand, just before the end of the upward movement of the plunger 12, the discharge groove 17 of the plunger 12 coincides with the spill port 15, the spill port 15 opens into the discharge groove 1γ, and the fuel in the pump chamber is discharged from the passage formed in the plunger 12. , discharge groove 17
, is discharged through spill port 15.

The relative angular position of the plunger 12 with respect to the barrel 11 is adjusted by the device described below, and since the edge of the discharge groove 17 is spiral-shaped, the angular position of the plunger 12 is set at the moment when the spill board 15 opens into the discharge groove 17. Determine.

A hollow sleeve 19 is disposed surrounding a portion of the barrel 11 at a location below the outlet 13, the lower end of the sleeve 19 having a pair of axial slots 20 extending from the outer end of the sleeve 19 to the inner end. It is formed towards.

A protrusion 21 formed on the plunger 12 is fitted into the slot 20 .

With this configuration, axial motion applied to the plunger 19 is not transmitted to the plunger 12, only angular motion is transmitted.

The outer circumferential surface of the sleeve 19 is formed with teeth that engage the teeth of a fuel control rod 22 that is movable circumferentially in the hollow member 10 relative to the plunger 12 .

At the outer end (lower end) of the plunger 12, a spring receiver 24
is disposed, and a spring 26 for pushing the plunger 12 outward is interposed between this and a washer 25 supported on the inner shoulder of the hollow member 10.

The spring receiver 24 is disposed in a cam follower 27 having a roller 28 which is placed in operative relationship with a cam 29 which is rotated by the engine to which the pump is connected.

Cam follower 2 to prevent angular movement of cam follower 27
7 is provided on both sides of the cam 29 with side wall portions 30 extending downward beyond the roller 28.

This side wall portion 30 cooperates with both sides of the cam 29 to prevent angular movement of the cam follower 27.

As shown in FIG. 2, a circumferential groove 32 is formed in the plunger 12 below a discharge groove 32. As shown in FIG.

The channel 32 collects fuel that leaks between the plunger 12 and the channel during inward movement of the plunger 12.

An inclined groove 33 communicates with the transparent groove 32 .

This inclined groove 33 terminates near the upper end of the plunger 12 and has approximately the same angle as the discharge groove 17.

Therefore, its position is diametrically opposite to the discharge groove 17.

Since the inclined groove 33 communicates with the transparent groove 32, this transparent groove 3
Receives the pressure of the fuel in 2.

This pressure is an intermediate pressure between the pressure in the pump chamber and the pressure in the hollow chamber of the main body housing the cam 29.

The pressure in the inclined groove balances the side pressure acting on the plunger due to the pressure of the fuel in the exhaust groove 17.

The fuel in the through groove 32 and the inclined groove 33 is extracted to the outside during the inward movement of the plunger 12.

For this purpose, an opening 34 is provided, as shown in particular in FIG.
During the upward movement of step 2, the groove 33 is located at a position that coincides with the inclined groove 33.

In the embodiment, the spill port 15 and the opening 34 are at the same height, and the inclined groove 33 coincides with the opening 34 just before the spill pole 15 coincides with the discharge groove 17, so that the inclined groove 33 and the opening 34 communicate with each other. placed in position.

Since the inclined groove 33 is parallel to the discharge groove 17, the inclined groove 33
The timing of said communication between and opening 34 occurs regardless of the angular position of plunger 12.

The flow of fuel that occurs when the opening 34 communicates with the inclined groove 33 washes away contaminants that collect in the groove 32, 33, and wear of the plunger 12 and its duct is minimized.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a fuel injection pump device of the present invention, and FIG. 2 is an explanatory diagram showing a main part of the device shown in FIG. 1 developed. 12... Plunger, 15... Spill port, 17... Groove, 32... Transparent groove,
33... Slanted groove, 34... Opening.

Claims (1)

[Claims] 1. A plunger that can reciprocate in a guide hole, a pump chamber composed of this guide hole and an inner end surface of the plunger, a fuel outlet from the pump chamber, and a fuel outlet drilled in the plunger with one side opening into the pump chamber. and a spill port formed in the wall of the guide hole, the other opening being formed in the circumferential surface of the plunger and at which the other opening of the passage is located and at the end of the inward movement of the plunger. an angled exhaust groove communicating between the pump chamber and the spill port to allow fuel remaining in the pump chamber to escape through the spill port, terminating the flow of fuel through the fuel outlet. In the injection pump device, a circumferential groove is formed on the circumferential surface of the plunger at a position below the discharge groove of the plunger to collect fuel leaking between the plunger and the guide hole; an inclined groove formed at a position on the opposite side of the drain groove at an angle substantially equal to the drain groove and communicating with the through groove; and an opening formed in the wall of the guide hole. , wherein the inclined groove communicates with the opening so that fuel collected in the permeable groove escapes through the opening upon inward movement of the plunger.