JPH05256226A - Fuel injection pump for internal combustion engine - Google Patents

Abstract

PURPOSE: To prevent bending oscillations of an adjusting lever shaft by providing at least one additional support bearing disposed between the two ends of the adjusting lever shaft at the point of maximum oscillation amplitude in a pump casing. CONSTITUTION: An adjusting lever shaft 10 is provided for the purpose of operating all the control slides 7 simultaneously. The two ends of the adjusting lever shaft 10 are supported on a pump casing 1 and connected to control slides 7. In a pump of this type, at least one additional support bearing 11 is provided between the two ends of the adjusting lever shaft 10 at the point of maximum oscillation amplitude in the pump casing 1. Thus, the bending oscillations of the adjusting lever shaft 10 can be reduced by the additional intermediate support for the adjusting lever shaft 10 by the support bearing 11 at the point of maximum oscillation amplitude.

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 used in an internal combustion engine, in which a plurality of pump plungers arranged in a row are provided in a pump casing, and the pump plungers have a common cam. Each shaft is reciprocally driven in a pump cylinder, limits a pump working chamber in the pump cylinder, and has one control slider axially slidable along each pump plunger. The control slider,
An outlet opening on the outer peripheral surface of the pump plunger of a passage communicating with the pump working chamber in the pump plunger is controllable, and a suction chamber surrounding each of the control sliders is provided, and the suction chamber is a pump. It is restricted by the casing and is adapted to be flowed by a low pressure fuel, and further there is provided an adjusting lever shaft provided for simultaneously operating all said control sliders, said adjusting lever shaft comprising: , Of the type supported on the pump casing at both ends and connected to the control slider.

[0002]

2. Description of the Related Art Fuel injection pumps of this type are already known from DE-A-3546222. In this known fuel injection pump, a control slider axially slidably arranged on a pump plunger surrounding a pump working chamber in a pump cylinder is located on an outer peripheral wall of the pump plunger, and a pump working is performed through a passage. It cooperates with a control groove connected to the chamber to control the timing of high pressure pumping. The control slider is then slid by the adjusting lever,
The adjusting lever is arranged on the adjusting lever shaft. The adjusting lever shaft is arranged in a suction chamber extending over the entire length of the fuel injection pump, and both ends of the adjusting lever shaft are guided through two bearing bushes that close the suction chamber on the end face side. ing.

In such a slider-controlled fuel injection pump, accurate and synchronous guidance of the individual control sliders is extremely important for the injection quality, and thus the combustion quality in the internal combustion engine. In particular, in a multi-cylinder fuel injection pump, slight bending of the adjusting lever shaft and bending vibration occur due to the high load on the adjusting lever shaft caused by the shocking rotation and the high closing control pressure of the control slider. It is born. Not only does this cause the individual control sliders to be out of synchronization with one another, but, due to the high vibration amplitude, additionally increased wear phenomena occur at the bearing points of the adjusting lever shaft.

Therefore, the structure of the known fuel injection pump is imposed on the guide of the adjusting lever shaft of the multi-cylinder type fuel injection pump in order to avoid an injection timing error caused by bending vibration of the adjusting lever shaft. Have not met the requirements.

[0005]

SUMMARY OF THE INVENTION The object of the invention is to improve a fuel injection pump of the type mentioned at the outset such that the disadvantages mentioned above are avoided and bending vibrations of the adjusting lever shaft are avoided. Is to provide a pump.

[0006]

In order to solve this problem, in the structure of the present invention, at least the adjusting lever shaft is additionally arranged between both ends at a position of maximum vibration amplitude in the pump casing. It had one support bearing.

[0007]

The fuel injection pump according to the present invention has the following advantages over the conventional one. In other words, the bending vibration of the adjusting lever shaft can be reduced because the adjusting lever shaft is additionally intermediately supported by the support bearing at the point of maximum vibration amplitude. This avoids injection start errors and increased bearing wear due to bending vibrations of the adjusting lever shaft, especially in multi-cylinder stroke-slider row pumps with eight or more pump elements. Since a precise injection start is obtained over the life of the fuel injection pump, it also has an advantageous effect on the combustion quality of the internal combustion engine to which the fuel is to be supplied.

In order to maintain a simple mounting of the adjusting lever shaft, despite the fact that a supporting bearing is provided,
After mounting the adjusting lever shaft in the pump suction chamber, it is advantageous if the support bearing is externally mounted and adjusted. For this purpose, an opening is provided in the pump casing as in the structure according to claim 12, and the opening is tightly closed after the support bearing is assembled or adjusted in position. Different support bearing variants are used, depending on the required degree of horizontal and vertical oscillating movement or the existing construction space.

The bearing composed of a plurality of pins screwed into the pump casing as described in claims 2 and 3 has the following advantages. That is,
Both horizontal and vertical bending vibrations are damped without the need for additional construction space in the pump casing. Further, such a modified bearing configuration allows rear position adjustment and individual adjustment of the assembled bearing in any direction. Another advantage of this arrangement is that the pin tip produces less friction through point contact on the adjusting lever shaft.

According to another bearing possibility according to claim 4, the horizontal and vertical movement of the adjusting lever shaft is L.
Only one direction in each case is restricted by the support bearings in the shape of a letter. In this case, even such a simple bearing shape is already sufficient to avoid bending vibration of the adjusting lever shaft. If it is desired to limit only the bending vibration in the vertical direction in both directions, the two-point bearing according to claim 5 is advantageous,
On the other hand, in order to avoid horizontal and vertical movements of the adjusting lever shaft, a three-point bearing according to claim 6 is used.

If it is desired to make the assembled additional support bearings adjustable after assembly, it is advantageous to use a bearing shell which is externally adjustable by means of an eccentric, as described in claim 7. is there.

In order to completely avoid the vertical and horizontal movements of the adjusting lever shaft by means of the additionally arranged supporting bearings, the supporting bearings, as set forth in claim 11, provide complete adjustment of the adjusting lever shafts. It consists of two bearing half shells that surround the.

Therefore, it becomes possible to limit the bending vibration of the adjusting lever shaft by means of the support bearing arranged at the location of maximum bending vibration.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Six embodiments of the present invention will be described below in detail with reference to the drawings.

In the fuel injection pump shown in FIG. 1, eight cylinder bushes 2 are inserted in a row in a casing 1. In these cylinder bushes, each one pump plunger 3 is axially moved by a cam shaft (not shown). A partial suction chamber 5 is formed by a cylindrical notch 4 laterally machined in the cylinder bush 2. This partial suction chamber encloses each one pump plunger 3 which emerges from the cylinder bushing 2 at this location. In this partial suction chamber 5, the pump plunger 3
One control slider 7 is arranged along each side so as to be slidable in the axial direction. The individual partial suction chambers 5 open on the outflow side into a tubular main suction chamber 8 which extends over the entire length of the casing 1, which main suction chamber is closed at its longitudinal end by a bearing bush 9. An adjusting lever shaft 10 which can be rotated from the outside is arranged in the main suction chamber 8. This adjusting lever shaft comprises a bearing bush 9 and, in addition to this bearing bush, a support bearing 1 between the fourth pump element and the fifth pump element.
1 is rotatably supported, and the control slider 7 can be slid by the adjusting lever shaft. For this purpose, the adjusting lever shaft 10 is provided with an adjusting lever 13 which projects in the radial direction and is associated with each one control slider 7. The adjusting lever is engaged in a notch 14 facing the main suction chamber 8 of the control slider 7. The pump plunger 3 limits a pump working chamber (not shown) in the cylinder hole of the cylinder bush 2, and this pump working chamber is connected to an injection nozzle (not shown). The pump plunger 3 is provided with a passage in the form of a central blind hole 21 opening into the pump working chamber, as is known from the known prior art. This passage, i.e. the blind hole 21, opens into a lateral hole, which originates from an inclined groove provided on the outer peripheral surface of the pump plunger 3. The inclined groove forming the control notch cooperates with a radial hole 15 provided in the control slider 7, in which case the inclined groove forms the radial hole 15 after the pump plunger 3 has gone through a defined stroke. Controlled by the partial suction chamber 5
Connected to. In order to prevent relative rotation of the control slider 7 when the control slider 7 axially slides along the pump plunger 3, the control slider 7 is provided with a web 16 protruding radially. This web engages a longitudinal groove 17 provided in the cylinder bush 2.

The fuel supply to the individual partial suction chambers 5 is common to all eight partial suction chambers 5 by means of one inflow passage 19. This inflow passage is connected to the partial suction chamber 5 via a lateral hole 20.

FIG. 2 shows a first variant of the support bearing 11 additionally arranged on the adjusting lever shaft 10 according to the construction of the invention. In this case, pins 25, 26, 27 are provided which are screwed from the outside through three walls which limit the tubular main suction chamber 8. Pins 25 and 2
The tips 29 of 6, 27 are preferably spherical and are in contact with the adjusting lever shaft 10. In this case, the tip portion guides the adjusting lever shaft 10 to prevent shift movement of the adjusting lever shaft 10. Pins 25, 26, 2
7 is a common radial plane of the adjusting lever shaft 10,
It acts on the adjusting lever shaft 10 from three sides, in which case the first pin 25 forms a contact point for the adjusting lever shaft 10 from above in the vertical direction and the second pin 26.
Is a horizontal direction, and is in contact with the adjusting lever shaft at a height of the central axis of the adjusting lever shaft 10 from a direction opposite to the pump plunger 3, and a third pin located opposite to the first pin. Reference numeral 27 is a vertical direction, and the adjustment lever shaft 1 is from below.
At 0, the displacement of the adjusting lever shaft is limited. The vertically arranged pins 25, 27 are tilted in a direction opposite to the pump plunger 3 by a certain angle from an axis extending parallel to the pump plunger axis for the purpose of improving the assembly. .. At the ends of the pins 25, 26, 27 that are arranged in cup-shaped recesses 28 (only the recesses that are located in the horizontal direction are shown) protruding from the main suction chamber 8 through the wall of the casing 1, A set nut 32 is screwed into the provided male thread 30. This lock nut contacts the casing 1 and the pin 2
It prevents the automatic movement of 5, 26 and 27. In addition, the pin has a lateral groove 34 at the end 33 opposite the tip 29, into which the screw 25, 26, 27 is screwed into the main suction chamber 8. A tool for adjusting the depth is adapted to be engaged. Pin 2
The sealing of the cup-shaped recess 28, which accommodates 5, 26, 27, is effected via a respective closure element screwed into the casing 1, which closure element is formed as a closure screw 36. The head part 37 of this closing screw presses a sealing ring 38 onto the casing 1.

In FIG. 3, the second of the additional support bearings 11 is shown.
Examples are given. The adjusting lever shaft 10 is guided in only one movement direction in each of the horizontal direction and the vertical direction via a bearing shell 40 that surrounds the adjusting lever shaft in an L shape. In this case, the support bearing 11 is inserted into the main suction chamber 8 and in this case the horizontal leg 41
And a horizontal surface 47 of the vertical leg 42, which faces the leg, extends parallel to the adjustment lever axis 31 and the main suction chamber surface 4 of the casing 1.
4 to guide the bearing shell 40 in the vertical direction. Also in this second embodiment, the support bearing 11 is inserted from the outside through the casing opening 49. As a stop on the pump plunger side for the horizontal leg 41 of the L-shaped bearing shell 40, a step 46 formed by an enlarged diameter portion 45 provided on the casing wall on the main suction chamber side acts. The bearing shell 40, on the other hand, is retained by a closure member in the form of a cover 43 which closes the casing opening 49 tightly.

Similar to the second embodiment, in the third embodiment of the support bearing 11 shown in FIG. 4, the movement of the adjusting lever shaft 10 is restricted by the two-point bearing 51 only in the vertical direction. The two-point bearing 51 is also insertable into the main suction chamber 8 through the casing opening 49 and has a U-shape that opens toward the pump plunger 3. The two horizontal legs 41 enclose and grip the adjusting lever shaft 10 by means of an inner surface 52, in which case the outer surface 53 contacts the casing wall 1 of the main suction chamber 8 extending parallel to said adjusting lever shaft 10. And is therefore guided vertically. Each one enlarged diameter portion 45 arranged on this casing wall forms a step portion 46 as a stopper of the two-point bearing 51 in the direction of the pump plunger 3.
On the other hand, in the opposite direction in the horizontal direction, the cover 43 closing the casing opening 49 acts as a stopper. In the horizontal direction, the bottom 5 of the U-shaped two-point bearing 51
Since 4 is spaced with respect to the adjusting lever shaft 10, horizontal movement of this adjusting lever shaft is possible.

The fourth embodiment shown in FIG. 5 differs from the third embodiment shown in FIG. 4 only in the following points. That is, the horizontal spacing between the adjusting lever shaft 10 and the U-shaped bearing shell 55 is reduced so that the adjusting lever shaft 10 contacts the bearing shell 55, thus forming a three-point bearing. The three-point bearing limits the movement of the adjusting lever shaft 10 both in the vertical direction and in the horizontal direction on the side opposite to the pump plunger.

FIG. 6 shows a fifth embodiment of the support bearing 11 according to the present invention. In this case, the adjustment lever shaft 1
The zero movement is limited in the vertical and horizontal directions by an externally adjustable bearing shell 70 via an eccentric. The bearing shell 70 is rotationally symmetrical and has an outer peripheral surface 71 that partially surrounds the adjusting lever shaft 10.
Moreover, since it has a concave shape adapted to the outer diameter of the adjusting lever shaft 10, the adjusting lever shaft 10 is guided in one movement direction in the horizontal direction and the vertical direction. The axis projecting from the bearing shell 70 is arranged offset from the axis of symmetry of the bearing shell by a difference "e" and is joined to the cover 43 in the middle. Since this cover is rotatably supported in the casing opening, the rotation of the cover 43 allows the bearing shell 70 to be adjusted in its spacing via the adjusting lever shaft 10 without additional assembly work. This allows a simple, always-adjustable rear adjustment of the support bearing 11. The cover 43 is positionable in the selected rotational position and closes the casing opening.

In FIG. 7, a sixth of the additional support bearing 11 is shown.
Examples are given. In this case, the adjusting lever shaft 10 is completely surrounded by the two bearing halves 60. This bearing half shell blocks the movement of the adjusting lever shaft 10 in all directions except a small play. Similar to the embodiment shown in FIGS. 3, 4 and 5, the bearing half shell 60 is guided vertically in the casing wall 1 of the main suction chamber 8 and is formed by the diameter expansion 45 in the horizontal direction. It is supported by the stepped portion 46 and the cover 43 that closes the casing opening 49.

[Brief description of drawings]

1 is a cross-sectional view of a fuel injection pump according to the present invention.

FIG. 2 is a longitudinal sectional view showing a first modified embodiment of the additional support bearing.

FIG. 3 is a vertical sectional view showing a second modification of the additional support bearing.

FIG. 4 is a longitudinal sectional view showing a third modification of the additional support bearing.

FIG. 5 is a vertical sectional view showing a fourth modification of the additional support bearing.

FIG. 6 is a vertical sectional view showing a fifth modification of the additional support bearing.

FIG. 7 is a vertical sectional view showing a sixth modification of the additional support bearing.

[Explanation of symbols]

1 casing, 2 cylinder bushes, 3 pump plungers, 4 notches, 5 partial suction chambers, 7
Control slider, 8 main suction chamber, 9 bearing bush, 10 adjusting lever shaft, 11 support bearing, 1
3 adjustment levers, 14 notches, 15 radial holes, 16 webs, 17 longitudinal grooves, 19 inflow passages, 20 lateral holes, 21 blind holes, 25,2
6,27 pin, 28 concave portion, 29 tip portion, 30
Male thread, 31 adjusting lever axis, 32 locking nut, 33 end, 34 lateral groove, 36 closing screw, 37 head part, 38 sealing ring,
40 bearing shell, 41, 42 leg part, 43 cover, 44 main suction chamber surface, 45 diameter expansion part,
46 steps, 47 surfaces, 49 casing openings,
51 2-point bearing, 52 inner surface, 53 outer surface, 5
4 bottom part, 55 bearing shell, 60 bearing half shell, 70 bearing shell, 71 outer peripheral surface

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Johann Varga Federal Republic of Germany Beitheimheim-Bissingen Blumenstraße 6-3 (72) Inventor Reiner Hebeler Bretten-Eichenstraße 32 (72) Inventor Manfred Kramer Germany Schwieberdingen Paradisweg 25 (72) Inventor Josef Güntert Germany Gerlingen Berg Heimerweg 25 (72) Inventor Peter Baumgartner Austria St. Andre Sankt Andre 283 (72) Invention Heinz Ratmile Austria Harin Schwarzstrasse 8

Claims (12)

[Claims] 1. A fuel injection pump used in an internal combustion engine, comprising a plurality of pump plungers (3) arranged in a row in a pump casing (1), the pump plungers having a common cam. The shafts are reciprocally driven in the pump cylinder (2),
A pump working chamber is limited in the pump cylinder (2), and one control slider (7) axially slidable along each pump plunger (3) is provided by the control slider. An outlet opening on the outer peripheral surface of the pump plunger (3) of the passage leading to the pump working chamber in the pump plunger (3) is controllable and surrounds each control slider (7). 5) is provided, the suction chamber being restricted by the pump casing (1) to be flowed by the fuel of low pressure, and in addition all the control sliders (7) are operated simultaneously. A control lever shaft (10) is provided for this purpose, the control lever shaft being supported at both ends on the pump casing (1), In of the type that is connected to, while the adjusting lever shaft (10) at both ends, at least one support bearing is additionally arranged at the point of maximum vibration amplitude in the pump casing (1) (1
A fuel injection pump used in an internal combustion engine, characterized in that it has 1). 2. The support bearing (11) comprises a plurality of externally adjustable pins (25, 26, 27) supported on the pump casing (1), the head (29) of the pin. 2. The fuel injection pump according to claim 1, wherein the adjusting lever shaft is in contact with the adjusting lever shaft. 3. Fuel injection pump according to claim 2, characterized in that the pins (25, 26, 27) are prevented from moving automatically and are sealed and guided by the wall of the pump casing (1). .. 4. The fuel injection pump according to claim 1, wherein the support bearing (11) is configured as a bearing (40) surrounding and engaging the adjusting lever shaft (10) in an L-shape. 5. The fuel injection pump according to claim 1, wherein the support bearing (11) is configured as a bearing (51; 55) surrounding and gripping the adjusting lever shaft (10) in a U-shape. 6. The fuel injection pump according to claim 5, wherein the U-shaped bearing (55) supports the adjusting lever shaft (10) at three positions offset by 90 °. 7. The fuel injection pump according to claim 5, wherein the U-shaped bearing (51) supports the adjusting lever shaft (10) at two points facing each other. 8. The fuel injection pump according to claim 1, wherein the support bearing (11) comprises a bearing shell (70) which is externally adjustable by an eccentric. 9. An eccentric body of the adjustable bearing shell (70) is arranged on a flange securable to the pump casing (1) for introducing said bearing shell (70). The fuel injection pump according to claim 8, wherein the through opening is closed. 10. The fuel injection pump according to claim 8, wherein the bearing shell (70) is configured in the form of a roller with a semicircular support cross section. 11. The fuel injection pump according to claim 1, wherein the support bearing (11) consists of two bearing halves (60) completely surrounding the adjusting lever shaft (10). 12. The support bearing (11) can be introduced into a defined position through an opening provided in the wall of the pump casing (1), and further the support bearing (1).
1) is held in contact with the plug-in limiting part provided in the pump casing (1) by a closing part (43) that closes the opening provided in the wall of the pump casing (1). The fuel injection pump according to any one of claims 1 to 11.