JPS6118020B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention makes it possible to pump fuel by reciprocating a plunger within a barrel, and at the same time, it is possible to pump fuel by reciprocating a plunger within a barrel. By rotating the annular valve relative to the plunger using an appropriate metering lever so that the oil passage hole formed in the plunger can be opened and closed, the oil passage hole of the plunger and the oil escape hole formed in the annular valve can be connected. A rotary lever with a pinion gear is attached to the outer end of a timer pin that controls the fuel injection amount by changing the communication timing and has an eccentric head that engages with the annular valve in the axial direction of the plunger. The rotary lever with the pinion gear is appropriately rotated by a timer rack which has a rack gear that meshes with the pinion and is moved forward or backward in a direction orthogonal to the axial direction of the timer pin depending on the operating state of the engine, The present invention relates to a fuel injection valve for an internal combustion engine in which fuel injection timing can be adjusted by appropriately displacing the annular valve in the axial direction of a plunger using the timer pin.

Conventionally, in this type of fuel injection pump for internal combustion engines, the rack gear of a timer rack is engaged with the pinion gear of a rotating lever with a pinion gear attached to a timer pin, and the timer rack is moved forward and backward in the axial direction as needed. The timer pin was rotated appropriately via a rotating lever with a pinion gear, but in this case, since there was a bump in the gear part, the timer rack and the rotating lever with a pinion gear rattled during operation, resulting in There was a problem in that the annular valve moved loosely, making the fuel injection characteristics and advance angle characteristics unstable.

In view of the problems of conventional fuel injection pumps for internal combustion engines as described above, the present invention has been developed to suppress the play between the timer rack and the timer pin, thereby preventing the annular valve from floating and improving the fuel injection characteristics. This invention was developed for the purpose of providing a fuel injection pump for an internal combustion engine that is designed to stabilize advance characteristics. The present invention is characterized in that a suitable biasing member is interposed between the racks and acts to constantly bias the rotating lever with a pinion gear toward one side of the timer rack.

Hereinafter, the fuel injection pump for internal combustion engines of the present invention will be explained based on the embodiment shown in FIGS. 1 and 2. FIG. 1 shows a multi-cylinder in-line fuel injection pump Z according to the embodiment of the present invention. It is shown.

This fuel injection pump Z has a plunger 3 fitted into a barrel 2 so as to be relatively slidable, and the plunger 3 is moved by a spring force of a plunger spring 13 and a camshaft 17.
While the fuel can be pumped by reciprocating the cam 18 protruding from the cam 18, a cam 18 is formed on the outside of the plunger 3 and extends over the top surface 3a and side peripheral surface 3b of the plunger 3. The annular valve 5 is slidably and relatively rotatably fitted so as to be able to open and close the oil passage hole 4, and the annular valve 5 is slid relative to the plunger 3 as appropriate to prevent the passage of the plunger 3. The fuel injection amount can be controlled by changing the communication timing between the oil hole 4 and the oil escape hole 9 formed in the annular valve 5, and the fuel injection timing can be adjusted by displacing the annular valve 5 in the plunger axial direction. The pump body 1 is constructed by arranging an appropriate number of such single-tube pump units X in parallel in the pump body 1. Each annular valve 5, 5... of each pump single cylinder unit X,
They are each synchronously controlled by a metering operation lever 6 and a timer rack 7, which are arranged so as to be able to move forward and backward in a direction perpendicular to the axial direction. That is, the metering operation rod 6 is
A rack gear 12 formed on the side thereof is meshed with pinion gears 11, 11 formed on the outer peripheral surface of each annular valve 5, 5, . . . of each pump single cylinder unit X, X, . By moving the rod 6 forward or backward according to the operating state of the engine using a suitable governor device (not shown), each of the annular valves 5, 5... can be rotated as appropriate. . On the other hand, timer rack 7
As shown in FIGS. 1 and 2, a rack gear 7a formed on one side of the rack gear 7a is fitted with an eccentric head 8b that is properly eccentric with respect to the journal portion 8a into the circumferential groove 12 of the annular valve 5. Outer end 8 of timer pin 8
Each pump single-tube unit X, X attached to c...
The rotating levers 10 with pinion gears 10, 10... are meshed with the respective pinion gears 10a, 10a..., and each pinion gear is appropriately displaced in the axial direction by feed pressure proportional to the rotational speed of the engine. Rotating lever 10 with
The annular valves 5, 5... can be synchronously displaced in the plunger axial direction via the annular valves 5, 5...

In this case, the rack gear 7a of the timer rack 7
Since the pinion gear 10a of the rotary lever 10 with a pinion gear has a backlash, the rotary lever 10 with a pinion gear rattles against the timer rack 7 during operation, and as a result, the annular valve 5 moves loosely and the fuel injection characteristics and It is conceivable that the advance angle characteristics become unstable. In order to prevent this, in the fuel injection pump Z of the illustrated embodiment, a biasing member made of a torsion coil spring 16 is interposed between the timer rack 7 and the timer pin 8. That is, the coil portion 16 of the torsion coil spring 16
c is attached to the outer end surface 8d of the timer pin 8 with the spindle screw 14, while the torsion coil spring 1
One end 16a of 6 is engaged with the engagement protrusion 15 installed in the timer rack 7, and the other end 16b is rotated with a pinion gear while applying an appropriate spring force to the torsion coil spring 16. Lever 1
It is fixed to the outer end surface 10b of 0. By doing this, the rotating lever 10 with pinion gear
is always held by the spring force of the torsion coil spring 16.
It is biased toward one side of the timer rack 7 (in the illustrated embodiment, in the direction of arrow A), thereby absorbing rattling between the timer rack 7 and the rotating lever 10 with pinion gear (i.e., the timer pin 8). be done.

In FIG. 1, reference numeral 19 denotes an unevenness adjustment pin for adjusting the unevenness of the injection amount between the pump single cylinder units X, X, . . . .

Next, to explain the effects of the present invention, the fuel injection pump for an internal combustion engine of the present invention has an appropriate biasing member interposed between a timer rack and a timer pin that are gear-engaged with each other to prevent backlash of the gear part. Since it is designed to absorb the backlash between the two due to
This eliminates the possibility of the annular valve floating during operation, and has the effect of stabilizing the fuel injection characteristics and advance angle characteristics.

[Brief explanation of the drawing]

FIG. 1 is a fuel injection pump according to an embodiment of the present invention, and FIG. 2 is a view taken along the - arrow in FIG. 2...Barrel, 3...Plunger, 3a...Top surface of plunger, 3b...Side peripheral surface of plunger,
4... Oil hole, 5... Annular valve, 6... Metering operation rod, 7... Timer rack, 7a... Rack gear, 8... Timer pin, 8b... Eccentric head of timer pin, 8c... ...Outer end surface of timer pin, 9
... Oil escape hole, 10 ... Rotating lever with pinion gear, 10a ... Pinion gear, 16 ... Biasing member.

Claims (1)

[Claims] 1. Fuel can be pumped by reciprocating the plunger 3 within the barrel 2, and an oil passage hole is formed on the outside of the plunger 3 across the top surface 3a and side peripheral surface 3b of the plunger 3. 4 by fitting an annular valve 5 so as to be relatively rotatable and slidable relative to each other so as to open and close the annular valve 5, and by rotating the annular valve 5 relative to the plunger 3 using an appropriate metering operation rod 6. By changing the communication timing between the oil passage hole 4 of the plunger 3 and the oil escape hole 9 formed in the annular valve 5, the amount of fuel injection is controlled, and the relationship between the annular valve 5 and the plunger axial direction is controlled. Outer end 8 of timer pin 8 with mating eccentric head 8b
A rotating lever 10 with a pinion gear 10a is attached to c, and the rotating lever 10 with a pinion gear has a rack gear 7a that meshes with the pinion gear 10a, and is orthogonal to the axial direction of the timer pin 8 depending on the operating state of the engine. The timing of fuel injection can be adjusted by appropriately rotating the annular valve 5 in the axial direction of the plunger by rotating the timer pin 8 as appropriate by means of a timer rack 7 which can be moved forward and backward in the direction of the plunger. The fuel injection pump for an internal combustion engine is provided with an appropriate attachment between the timer pin 8 and the timer rack 7 that acts to always bias the pinion gear-equipped rotary lever 10 toward one side of the timer rack 7. A fuel injection pump for an internal combustion engine, characterized in that a force member 16 is provided.