JPH08105363A - Fuel injection pump for internal combustion engine - Google Patents

Abstract

PURPOSE: To facilitate adjusting work in the early stage and simplify the adjusting structure in adjusting fluctuation of a fuel injection quantity of a fuel injection pump. CONSTITUTION: The fuel injection pump for an internal combustion engine is composed of a control rack 4 which rotates a plunger 3 through a housing 1, a delivery valve 6, a cylinder 2, a plunger 3 and a sleeve 5. The plunger 3 is consisted of a tilted lead 31 for adjusting the fuel injection quantity and a fuel passage for communicating the tilted lead 31 with the end part on the delivery valve 6 side. The cylinder 2 has a fuel sustion/delivery port 21 opened on the tilted lead 31. The cylinder 2 is provided with a adjusting unit 29 for adjusting the position relating to the fuel suction/delivery port 21 and the tilted lead 31 and the housing 1 is provided with a jig hole 19 for inserting a rotation jig on the surface opposite to the adjusting unit 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection pump for an internal combustion engine, and more particularly to a structure of a fuel injection amount adjusting section thereof.

[0002]

2. Description of the Related Art As a conventional fuel injection pump for an internal combustion engine, for example, one having a structure shown in Japanese Utility Model Laid-Open No. 56-150862 is known. This conventional row type pump in which three pressure feeding system components are arranged in parallel will be described with reference to FIGS. 10 to 13.
That is, as shown in FIG. 10, the conventional pumping system component 9 includes a housing 91 and a delivery valve 6 disposed therein.
A pump element 30 including a cylinder 92 and a plunger 3, and a control rack 94 for rotating the plunger 3 via the sleeve 5. And these are provided by the number of cylinders of an engine, and are arranged in parallel in one housing.

The cylinder 92 is provided with a fuel intake / exhaust port 921 for intake / exhaust of fuel (see reference numeral 21 in FIGS. 7 and 8 described later). Also, the plunger 3 above
Has an inclined lead 31 for adjusting the fuel injection amount and a fuel passage 32 that connects the inclined lead 31 and the tip portion 33 of the plunger 3 (see FIG. 7). The inclined lead is provided in a strip shape obliquely with respect to the axial center of the plunger.

Therefore, the cylinder 92 and the plunger 3 can change the fuel injection amount by changing the positional relationship between the two in the rotational direction. Specifically, as shown in FIG. 13, the cylinder 92 is fixed to the housing 91 by a pin 912 so that it cannot rotate.
The injection amount is adjusted by rotating.

Further, as shown in FIG. 10, the sleeve 5 provided below the pump element 30 comprises a cylindrical portion 50 into which the plunger 3 is slidably inserted and a flange portion 51 provided at the upper end thereof. (See FIG. 9 described later). The cylindrical portion 50 is provided so as to interlock with the plunger 3 only in the rotating direction and not to restrain the plunger 3 in the sliding direction which is the axial direction (see FIG. 9). Further, on the upper surface of the flange portion 51 of the sleeve 5, the protruding ball portion 5 for engaging with the control rack 94 is provided.
2 (see FIG. 9) are provided.

Further, as shown in FIG. 11, the housing 9
Control rack 94 arranged to be movable left and right in 1
12, is connected to a rack body 940, two fork portions 941 for engaging with the ball portion 52 of the sleeve 5, a reference fork portion 944, and a rack drive portion (not shown). It is composed of rack pins 943.
The fork portion 941 other than the reference fork portion 944 is
Rack body 940 with fork fixing bolt 942
On the other hand, it is arranged so that it can be moved (moved, fixed) in the longitudinal direction (left and right direction in FIG. 12). In addition, the reference fork portion 944 is fixed so that the rack body 940 does not move.
It is fixed to.

In such a structure, while the internal combustion engine is operating, the control rack 94 is moved to the left and right, so that the sleeves 5 of the respective cylinders are simultaneously rotated by the same amount through the fork portions 941 and 941 and the reference fork portion 944. Move. Therefore, each plunger 3 connected to the sleeve 5 also rotates relative to each cylinder 92. As a result, the fuel injection amount for each cylinder can be controlled simultaneously. When injecting fuel,
By rotation of a cam shaft (not shown) that abuts the tappet 69 shown in FIG. 2 and the urging force of the plunger spring 65,
The plunger 3 slides in the cylinder 92, and the suction of fuel into the plunger chamber 25 and the pressure feed to the delivery valve 6 are repeated. The fuel fed under pressure pushes up the delivery valve 6 against the spring 62 and is injected from a nozzle (not shown).

[0008]

However, the above conventional fuel injection pump for an internal combustion engine has the following problems.
That is, in the pumping system component 9 having the pump element 30 having the above structure, the fuel injection amount varies among the pumping system components 9 due to subtle machining variations in the components. Therefore, the injection amount of the cylinder of the movable fork 941 is adjusted according to the injection amount of the cylinder of the reference fork unit 944. However, the variation between the fuel injection pumps is caused by the variation in the injection amount of the reference fork portion of each pump. That is, when the fuel injection pumps are operated with the position of the control rack 94 kept constant, the injection amounts injected from the respective pumps differ.

Therefore, in order to eliminate these variations, it is necessary to initially adjust the injection amount for each pump element 30 prior to actual use in the engine. In the conventional initial adjustment of the reference injection amount, the fork portion 941 arranged on the control rack 94 is used.
By moving the left and right to fix (relocate), the sleeve 5
, That is, the positional relationship between the plunger 3 and the cylinder 3 was changed. In other words, the position of the cylinder 2 is not moved, but the position of the sleeve 5 interlocking with the plunger 3 in the rotational direction is moved.

In order to adopt such an initial adjustment method, a fork portion 94 provided on the control rack 94 is provided.
1 is required to be movably arranged on the rack body 940. Therefore, the fork fixing bolt 94
2. The number of required parts, such as the processing of oblong holes that move this to the left and right, will increase, and the processing man-hour will also increase. Further, also in the above initial adjustment work, since the indirect parts such as the fork portion 941 are moved, the work is very complicated.

The present invention has been made in view of the above conventional problems, and in the adjustment of the variation of the fuel injection amount in the fuel injection pump, the initial adjustment work is easy,
Moreover, it is an object of the present invention to provide a fuel injection pump for an internal combustion engine having a simple adjustment structure.

[0012]

The present invention comprises a housing, a delivery valve arranged therein, a cylinder, a plunger arranged in the cylinder so as to be movable back and forth, and a sleeve for rotating the plunger. , A control rack for adjusting the fuel injection amount by rotating the plunger through the sleeve, and the plunger is
The outer peripheral surface of the cylinder has an inclined lead for adjusting the fuel injection amount and a fuel passage communicating between the inclined lead and the tip end on the delivery valve side. In a fuel injection pump for an internal combustion engine having a port, the cylinder is provided with an adjusting portion for adjusting a positional relationship between a fuel intake / exhaust port of the cylinder and the inclined lead of the plunger, and the housing is provided with A fuel injection pump for an internal combustion engine, characterized in that a jig hole for inserting a turning jig is provided on a surface facing the adjusting portion.

What is most noticeable in the present invention is that the cylinder is provided with the adjusting portion and the housing is provided with the jig hole. The slanted lead provided on the plunger is a strip-shaped cutout of a part of the sliding surface that comes in contact with the cylinder. There is.

Further, the plunger and the sleeve are arranged so as to engage with each other only in the rotating direction and not to restrain each other in the sliding direction, which is the axial direction thereof. Further, the control rack is engaged with the sleeve so that the sleeve can be rotated by its lateral movement. That is, the control rack, the sleeve, and the plunger are configured so that the sleeve and the plunger rotate when the control rack moves left and right.

Further, it is preferable that the adjusting portion of the cylinder is provided as a notch groove provided in the outer periphery of the cylinder in the axial direction thereof. As a result, the adjusting unit can be made to have a simple structure and the cost can be reduced.

The control rack is composed of a rack pin connected to the rack drive unit, a fork engaging with the sleeve, and a main body provided with both, and these are integrally molded by a metal injection molding method. It is preferable. As a result, the number of parts and processing man-hours can be reduced, and the manufacturing cost is also reduced.

Further, the fuel injection pump of the present invention can be applied not only to a row type pump in which a plurality of injection pumps such as a triple type are arranged in parallel, but also to a single type pump as shown in the embodiment. Further, the "initial adjustment" described in the present invention generally means an adjustment performed prior to actual use, but it goes without saying that it also includes the case of adjusting the variation in the injection amount that has occurred during actual use. .

[0018]

In the fuel injection pump for an internal combustion engine of the present invention, in the case of initially adjusting the above-mentioned reference injection amount of fuel, first, the rotating jig is attached to the adjusting portion of the cylinder through the jig hole of the housing. Abut. Next, by moving the turning jig to the left or right while it is in contact with the adjusting part,
Rotate the cylinder.

When the cylinder rotates, the positional relationship in the rotational direction between the fuel intake / discharge port of the cylinder opened on the sliding surface of the plunger and the inclined lead of the plunger changes. That is, the slanted lead provided on the plunger is provided not obliquely but obliquely. Therefore, the distance between the slanted lead and the tip of the plunger on the sliding surface in contact with the fuel intake / exhaust port changes. Therefore, the distance over which the plunger pumps the fuel changes, and the reference fuel injection amount can be adjusted (see FIGS. 5 to 7).

As described above, according to the present invention, it is not necessary to move, fix and adjust the fork portion of the control rack each time as in the conventional example, and the fuel can be simply rotated by directly rotating the cylinder. The reference injection amount can be adjusted initially. Moreover, compared with the conventional example, parts such as a fork fixing bolt can be omitted and the structure can be simplified. Therefore, according to the present invention, in adjusting the variation of the fuel injection amount in the fuel injection pump,
It is possible to provide a fuel injection pump for an internal combustion engine in which the initial adjustment work is easy and the adjustment structure is simple.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A fuel injection pump for an internal combustion engine according to an embodiment of the present invention will be described with reference to FIGS. The fuel injection pump for an internal combustion engine of this example is a row type pump in which three pumping system components 10 are arranged side by side in the housing 1. As shown in FIG. 1, each pumping system component 10 includes a housing 1, a delivery valve 6 disposed therein, a cylinder 2, a plunger 3 arranged in the cylinder 2 so as to be able to move forward and backward, and the plunger 3 described above. And a sleeve 5 for rotating. Then, the sleeves 5 of the respective pumping system parts 10 are attached to the respective sleeves 5
A control rack 4 for rotating the plunger 3 to adjust the fuel injection amount is connected via the.

As shown in FIGS. 5 to 7, the plunger 3 has an inclined lead 31 for adjusting the fuel injection amount on the outer peripheral surface thereof, and the lead 31 and the delivery valve 6 are provided.
And a fuel passage 32 that communicates with the front end portion 33 on the side.
On the other hand, as shown in FIGS. 7 and 8, the cylinder 2 has the lead 3 when the plunger 3 moves in its axial direction.
1 has a fuel intake / exhaust port 21 opening to 1.

The cylinder 2 includes the cylinders shown in FIGS.
As shown in FIG. 8, an adjusting unit 29 is provided for adjusting the positional relationship between the fuel intake / exhaust port 21 of the cylinder 2 and the lead 31 of the plunger 3. In addition, the housing 1
As shown in FIGS. 1 and 4, a jig hole 19 for inserting a turning jig is provided on the surface facing the adjusting section 29.

The adjusting portion 29 of the cylinder 2 is shown in FIG.
As shown in FIG. 3, it is a notch groove provided in the axial direction on the outer circumference of the cylinder 2. The cylinder 2 is pressed and fixed by fastening the valve holder 61 to the housing 1 as shown in FIG.

Further, as shown in FIG. 7, the slanted lead 31 provided on the plunger 3 is formed by cutting out a part of the sliding surface which comes into contact with the cylinder 2 into a band shape, and the slanted lead 31 with respect to the axial center of the plunger. It is not a right angle but a diagonal strip. In addition, the fuel passage 32 has the inclined lead 31
And the tip 33 of the plunger 3 communicate with each other.

Further, as shown in FIG. 9, the sleeve 5 is
It comprises a cylindrical portion 50 into which the plunger 3 is slidably inserted, and a flange portion 51 provided at the upper end thereof. The inner hole 55 of the cylindrical portion 50 has a two-face width hole shape and engages with the two-face width portion 35 of the plunger 3 in the rotation direction. Also,
A projecting ball portion 52 for engaging with the control rack 4 is provided on the upper surface of the flange portion 51 of the sleeve 5.

Further, as shown in FIGS. 1 and 2, a control rack 4 mounted on the housing 1 so as to be movable left and right.
As shown in FIG. 3, a rack body 40, a fork portion 41 for engaging with the ball portion 52 of the sleeve 5,
The rack pin 43 is connected to a rack driving unit (not shown). And these are integrally molded by the metal injection molding method. Other configurations are the same as the conventional example.

Next, the function and effect of this example will be described. In this example, when initially adjusting the reference fuel injection amount of the pump element 30, first, the valve holder 6
Loosen one. As a result, the cylinder 2 in the housing 1
To be rotatable. Then, as shown in FIG. 5a, the rotation jig 7 is passed through the jig hole 19 of the housing 1 and the cylinder 2
The adjustment unit 29 of the above is abutted. Next, for example, when increasing the reference injection amount of fuel, as shown in FIG.
The rotating jig 7 is moved in the direction of arrow C. As a result, the cylinder 2 rotates as indicated by the arrow D.

By the rotation of the cylinder 2, the pressure feeding start position of the fuel suction / discharge port 21 of the cylinder 2 opened on the sliding surface of the plunger 3 is located at A1 as shown in FIG. Move to. Similarly, the position where the pressure feeding ends is located at A2 moves to B2. That is, the pumping length by which the plunger 3 pumps the fuel changes from L1 to L2, and the fuel injection amount can be increased. On the contrary, when the fuel injection amount is reduced, it can be easily adjusted by moving the jig 7 in the direction opposite to the above direction (the direction opposite to the arrow C in FIG. 6).

Finally, after the rotation adjustment of the cylinder 2 is completed, the valve holder 61 is tightened to fix the cylinder 2 and the initial adjustment of the pump element 30 is completed. Moreover, when initializing a plurality of pump elements 30, the same work is performed for each pump element 30.

As described above, according to the present example, it is not necessary to move and fix the fork portion 41 of the control rack 4 each time as in the conventional example, and it is possible to simply rotate the cylinder to easily adjust it. The fuel reference injection amount can be initially adjusted. Moreover, compared with the conventional example, parts such as a fork fixing bolt can be omitted and the structure can be simplified.

Therefore, according to this example, in adjusting the variation of the fuel injection amount in the fuel injection pump, the initial adjustment work is easy and the adjustment structure is simple.
A fuel injection pump for an internal combustion engine can be obtained. Also,
In this example, the components of the control rack 4 are integrally molded by a metal injection molding method. Therefore, the number of parts and the number of processing steps can be reduced, and the manufacturing cost can be reduced. The fuel passage 32 is connected to the plunger 3
It can also be formed by providing a through hole in the axial direction.

[Brief description of drawings]

FIG. 1 is a sectional view of a fuel injection pump according to an embodiment.

FIG. 2 is a front view of the fuel injection pump according to the embodiment.

FIG. 3 is a front view of a control rack according to the embodiment.

FIG. 4 is a rear view of the fuel injection pump according to the embodiment.

FIG. 5A is a sectional view of a main part of a plunger according to the embodiment and FIG.

FIG. 6 is an operation explanatory diagram of initial adjustment of the fuel injection amount in the embodiment.

FIG. 7 is a structural explanatory view of a cylinder and a plunger in the embodiment.

FIG. 8 is a side view of the cylinder in the embodiment.

FIG. 9 is a structural explanatory view of a plunger and a sleeve in the embodiment.

FIG. 10 is a sectional view of a conventional fuel injection pump.

FIG. 11 is a front view of a fuel injection pump in a conventional example.

FIG. 12 is a front view of a control rack in a conventional example.

FIG. 13 is a rear view of a conventional fuel injection pump.

[Explanation of symbols]

 1. . . Housing, 10. . . Pumping system parts, 2. . . Cylinder, 21. . . Fuel inlet / outlet, 3. . . Plunger, 31. . . Inclined lead, 32. . . Fuel passage, 4. . . Control rack, 40. . . Rack body, 41. . . Fork part, 43. . . Rack pin, 5. . . sleeve,

Claims (3)

[Claims] 1. A housing, a delivery valve disposed therein, a cylinder, a plunger disposed in the cylinder so as to be movable back and forth, and a sleeve for rotating the plunger. And a control rack for adjusting the fuel injection amount by rotating the plunger, and the plunger has an inclined lead for adjusting the fuel injection amount on the outer peripheral surface thereof, and the inclined lead and the tip end on the delivery valve side. In a fuel injection pump for an internal combustion engine, wherein the cylinder has a fuel inlet / outlet opening to the inclined lead, and the cylinder includes a fuel inlet / outlet of the cylinder and a plunger. An adjusting portion is provided for adjusting the positional relationship with the inclined lead, and the housing has a surface facing the adjusting portion. A fuel injection pump for an internal combustion engine, characterized in that a jig hole for inserting a turning jig is provided in the. 2. The fuel injection pump for an internal combustion engine according to claim 1, wherein the adjusting portion of the cylinder is a notch groove provided on an outer circumference of the cylinder in an axial direction thereof. 3. The control rack according to claim 1, wherein the control rack includes a rack pin connected to a rack drive section,
A fuel injection pump for an internal combustion engine, comprising: a fork that engages with the sleeve; and a main body provided with both, and these are integrally molded by a metal injection molding method.