JPH0457868B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a fuel injection pump for an internal combustion engine, which has a pump piston having a stroke disk and driven by a shaft. runs along an axially supported roller, in which case the pump piston is adapted to perform an additional stroke movement and has a plurality of return springs which bring the stroke disk into contact with the roller, and the pump piston has a plurality of return springs which bring the stroke disk into contact with the roller. The spring is supported by the pump casing and the spring receiver of the pump piston,
having a guide pin guided within the pump casing and arranged coaxially with respect to the return spring;
This relates to a type in which a guide pin passes through a spring receiver.

PRIOR ART An injection pump of the above type is known, for example from German patent application no. It consists of a damping chamber formed by and filled with fuel. Although the known device can be retrofitted to existing types of injection pumps, in addition to the injection function of the pump piston, additional auxiliary functions must always be provided, which cannot be achieved without problems.

Problem to be Solved by the Invention It is an object of the invention to improve a fuel injection pump of the type mentioned at the outset, to eliminate the drawbacks of the known technology and to make it technically easier to separate the stroke disk from the rollers. The goal is to make it possible to prevent this from happening.

Means for Solving the Problems In order to solve the above problems, in the structure of the present invention, a spring member and a sleeve are arranged on the guide pin in the direction of action, and the distance between the sleeve and the spring receiver is It is provided that the spring member is pressed against the spring receiver via the sleeve at the latest at the end of the discharge stroke.

Effects of the Invention According to the configuration of the present invention, based on the fact that the stroke disk is prevented from separating from the roller on the guide pin, the spring means for preventing the stroke disk from separating from the roller is mounted on the pump piston. It has become technically easy to provide this without adversely affecting functionality.

Advantageous embodiments of the invention are defined in claim 2.
It is described below. By prestressing the disc spring according to the embodiment claimed in claim 4, the disc spring is loaded only at the time of the speed change during the delivery stroke, so that the service life of the disc spring is increased.

According to the embodiment described in claim 5,
Stepless adjustment of the spring stroke of the disc spring becomes possible. The embodiment according to claim 6 is particularly suitable for fuel injection pumps which do not have a maximum discharge velocity such that the disc spring is easily loaded during the suction and discharge processes.

Embodiment As shown in FIG. 1, a pump piston 11 is provided in a casing 10 of a distribution fuel injection pump for an internal combustion engine, which is driven in the direction indicated by an arrow 9 via a shaft (not shown). is accepted. The pump piston 11 has a stroke disk 12, the cam surface 13 of which runs on rollers 14 of an axially supported roller ring 15, so that the pump piston 11 is additionally provided with a stroke movement indicated by the double arrow 8.

Due to the rotational and stroke movement of the pump piston 11, fuel is sucked from the inner chamber 16 of the injection pump into a high-pressure chamber (not shown) and then via a line 17 using an adjusting lever 18. control hole 1
9 to the internal chamber 16 until it is controlled to open to the individual cylinders of the internal combustion engine.

The first and second (not shown) return springs 20 are constructed as helical compression springs, which are supported on the one hand in a spring catch 21 of the pump piston 11 and on the other hand in a first ring shoulder. 22
This ring shoulder is in contact with the sleeve 24.
The sleeve is arranged slidably along a guide pin 25 inserted into a bore 26 of the casing 10, the guide pin being parallel to the pump piston 11. and is engaged with the opening 27 of the spring receiver 21 with play.

A disc spring 28 configured as a spring set coaxially surrounds the guide pin 25 and on the other hand
and on the other hand a standard plate 30, which itself rests on the bottom 32 of a recess 31 in the casing 10, in which case the recess 31 is in contact with the countersunk. A spring 28 is received.

In the embodiment shown in FIG. 2, the same parts as in the embodiment shown in FIG. 1 are given the same reference numerals. The guide pin 35 inserted into the bore 26 of the casing 10 has an axial shoulder 36 formed by reducing its diameter and a ring groove 37 with a snap plate 38; 1st snap plate
A second axial surface 40 of the snap plate supports a disc spring 28 in the axial surface 39 of the snap plate, and a second axial surface 40 of the snap plate
1 is in contact with the bottom 32 of 1. Axial shoulder 36
and the first axial surface 39 is such that it is possible to preload the disc spring 28 in the rest position of the injection pump.

The edge 42 of the recess 31, which receives the disc spring 28, is covered by a perforated plate 41, in which case the hole 43, which receives the sleeve 34 with play, forms a spring cage for the disc spring 28 as a whole. The diameter is specified so that a

In the embodiment shown in FIG. 3, the same parts as in the previous embodiment are given the same reference numerals. In contrast to the previously described embodiments, the guide pin 45 has a coaxial threaded bolt 46, the external thread of which is adapted to cooperate with the internal thread of a threaded sleeve 47, the threaded sleeve being an integral part. It has an outer flange 23 as part and is guided into a blind hole 48 of the housing 10, with a prestressed disc spring 28 holding the outer flange 23 against the bottom 32.

By rotating the threaded sleeve 47, the threaded pin 46 cooperating with this threaded sleeve is moved in one direction or the other as indicated by the double arrow 49, in which case the sleeve 34 is moved correspondingly in the axial direction;
This increases or decreases the prestress of the disc spring 28.

In the embodiment shown in FIG. 4, the disk spring is tensioned to the preload of the return spring.

In the diagram shown in the upper part of FIG. 5, the horizontal direction represents the rotation angle α of the pump piston (FIG. 1) and the vertical direction represents the stroke h. In an injection pump with a normal discharge volume, the stroke disk 12 is always connected to the roller 1 during the suction and discharge strokes of the pump piston 11.
4 and as a result the pump piston 11
moves along a stroke curve 50. In injection pumps with large delivery speeds, the stroke disk 12
is the point in time 5 when the speed of the pump piston 11 decreases 51a.
1 leaves the roller 14, so that the pump piston moves along the partial curve 52 and reaches the bottom dead center UT.
At the time 53 when the discharge direction is shifted from the top dead center to the top dead center, the roller 14 is contacted again, and the contact is thus effected impulsively.

Although the device according to the invention does not completely avoid the above-mentioned separation of the pump piston 11, it does hold down the pump piston 11, as indicated by the dashed line 54, so that the pump piston lowers at point 55, also depending on the rotational speed. It contacts the roller 14 again before reaching the dead center UT or immediately after the bottom dead center.

In the diagram shown at the bottom of FIG. 5, the rotation angle α of the pump piston 11 is also plotted in the horizontal direction, and the speed is plotted in the vertical direction. The speed curve 56 belonging to the stroke curve 50 is at the time 51a.
has a maximum height at , from which the pump piston speed decreases to top dead center and is converted in a similar manner into the negative speed range.

The stroke progression of the pump piston 11 shown in FIGS. 1 to 4 is as follows: As shown in FIG. contact roller 14 up to a maximum speed of , at which point return spring 20 performs a spring stroke 57 (FIG. 1). The spring receiver 21 then compresses the disc spring via the sleeve 24, so that the pump piston 11 moves along the dashed line 54.
A partial curve indicated by is drawn, and the stroke curve 50 is reached before the bottom dead center UT or immediately after the bottom dead center UT.

[Brief explanation of the drawing]

The drawings show embodiments based on the present invention; FIG. 1 is a partial sectional view of the first embodiment, FIG. 2 is a partial sectional view of the second embodiment, and FIG. 3 is a partial sectional view of the third embodiment. A partial sectional view, FIG. 4 is a partial sectional view of the fourth embodiment,
FIG. 5 is a diagram showing the stroke and speed curves of the pump piston. 10...Casing, 11...Pump piston, 1
2... Stroke disk, 13... Cam surface, 14... Roller, 1
5...Roller ring, 16...Inner chamber, 17...Pipe line, 1
8...Adjustment lever, 19...Control hole, 20...Return spring, 21...Spring receiver, 22...Ring shoulder, 23...
Outer flange, 24...sleeve, 25...guide pin,
26... Hole, 27... Opening, 28... Belleville spring, 29... Ring shoulder, 30... Standard plate, 31... Recess, 3
2... Bottom, 34... Sleeve, 35... Guide pin, 3
6... Axial direction shoulder, 37... Ring groove, 38... Snap plate, 39 and 40... Axial direction surface, 41
... Plate with holes, 42... Edge, 43... Hole, 45...
Guide pin, 46... Threaded bolt, 47... Threaded sleeve, 48... Blind hole, 50... Stroke curve, 51... Time point,
52... Partial curve, 53... Time point, 54... Broken line, 55
... Time point, 56... Velocity curve.

Claims (1)

[Scope of Claims] 1. A fuel injection pump for an internal combustion engine, comprising a pump piston having a stroke disk and driven by a shaft, the stroke disk being mounted on a roller supported in the axial direction. The pump piston runs along the same axis, in which case the pump piston carries out an additional stroke movement, and has a plurality of return springs which bring the stroke disk into contact with the rollers, the return springs being arranged to move the pump casing and the pump piston together. A pump of the type supported by a spring receiver, having a guide pin guided in the pump casing and arranged coaxially with respect to the return spring, the guide pin passing through the spring receiver, A spring member 28 is placed on the guide pins 25, 35, 45.
and sleeves 24, 34 are arranged front and back in the direction of action, and the sleeves 24, 34 and the spring receiver 21
A fuel injection pump for an internal combustion engine, characterized in that the distance between the spring member 28 and the spring member 28 is such that the spring member 28 presses the spring receiver 21 through the sleeves 24 and 34 at the latest at the end of the discharge stroke. . 2. The spring member is a disc spring 28 that coaxially surrounds the guide pins 25, 35, 45, and the disc spring is configured as a single disc, a spring set, or a spring support. fuel injection pump. 3 The spring plate 28 is located in the recess 3 of the pump casing 10
1. A fuel injection pump according to claim 2, wherein the fuel injection pump is located within a fuel injection pump. 4 The guide pin 35 is attached to the sleeve 34 in the spring side section.
It has an axial shoulder 36 formed by diameter reduction for supporting the casing-side section and is provided with a collar 38 whose axial surface 40 extends over the bottom 32 of the recess 31. and the spacing between the axial shoulder 36 and the axial surface 40 is defined in such a way that a preload is created on the disc spring 28. Fuel injection pump as described. 5 The outer flange 23 is a blind hole 48 in the bottom 32 of the recess.
It is an integral part of the threaded sleeve 47 introduced therein, and the guide pin 25 has a coaxial threaded bolt 46 such that the external thread of the threaded bolt cooperates with the internal thread of the threaded sleeve 47. A fuel injection pump according to claim 4. 6. The sleeve 24 has an axial outer flange 23 in which one ring shoulder 22 contacts one end section of the return spring 20 and the other ring shoulder 29 contacts a disc spring 28. 3. A fuel injection pump according to claim 1 or 2, wherein one end section of the fuel injection pump is in contact with the other end sections. 7 The recess 31 that receives the disc spring 28 is covered by the holed plate 41, and the holed plate 41
7. The fuel injection pump according to claim 3, wherein the diameter of the hole 43 is defined so as to form a spring cage for the disc spring 26.