JPS5851265A - Fuel injection pump - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention includes a rotating fuel distributor and a cam ring for distributing fuel to an injection nozzle, the inwardly directed cams of the cam ring having rollers and spring-loaded cams, respectively. (5) The pump stroke is imparted by a relative rotary movement to at least one girdling radially guided in the pump casing via a tappet. A fuel injection pump of this type is known from German Patent Application No. 2,322,858 l). In fuel injection pumps of this type, the components that perform the stroke movement, namely the piston, rollers, sleeves and springs, are arranged separately in the pump housing. However, there are problems with this individual arrangement. This is because the individual arrangement impairs the stability of the injection pump and the large number of individual parts increases repair costs.

The fuel injection pump according to claim 1 of the invention substantially eliminates the disadvantages of the known technology. The idea of the invention is to guide the tappet from all directions and to receive other parts in the form of a cage.

Advantageous embodiments of the invention are described in the subclaims. With the embodiment of the fuel injection pump according to claim 2, the active position of the tappet is ensured and, in particular, rotation of the tappet about the stroke axis is avoided in a simple manner. The safety measures required for this purpose are provided by the embodiment according to claim 3 and are easily produced by the embodiment according to claim 4. The active position of the roller on the tappet can be achieved by the embodiment according to claim 5 in a satisfactory manner and without the need for additional parts. A simple and reliable positioning of the spring receiver relative to the piston is achieved by the embodiment according to claim 6.

After the fuel has been injected, it flows out of the individual stroke chambers onto the pump housing wall until the piston reaches the top dead center of the cam. It has been found that in this case, the fuel flow which is forced out with great force often causes cavitation in the pump casing walls, thereby reducing the functionality of the pump. According to the embodiment of the fuel injection pump according to the invention as claimed in claim 7, this cavitation is avoided by simple means. An easily manufacturable and reliably functioning connection of the two ring halves is provided by the construction as claimed in claim 8.O deflection ring as claimed in claim 9 If so constructed, only one fabric forming mold is required for both ring halves.

If the fuel injection pump is configured as described in claim 11, the strength of the hollow cylinder and thus the wall of the tappet is increased, and the component unit consisting of the piston, spring and tappet is The pump no longer comes apart when assembled or disassembled.

Next, embodiments of the present invention will be described in detail with reference to the drawings. The fuel injection pump shown in FIGS. 1 and 2 has a sleeve 10.
It is constructed as a radial pump having a pump casing consisting of a pump casing and a bushing 11 fixed therein. A slider 12 driven by a shaft (not shown) is rotatably and axially movably supported within this bushing 11 . The cam ring 13 has a plurality of inwardly directed cams 14 and is also driven by the shaft via seven flange 15.

A total of four pistons 16 are also each guided in a radial bore 8 of the bushing 11. Similarly four tappets 9
are each guided in a bore 17 of the bushing 11 and are provided with a hollow cylinder 2° and a bottom 18 with a groove 19. A roller 21 is rotatably supported within this groove 19. In this case, the cross section of the groove 19 is a circular surface portion having the same radius as the row 221, and the depth of the groove 19 is larger than the radius of this circular surface.

Each of the four tappets 9 has a piston 1 in the hole 17.
An o-coil spring 22, which is arranged coaxially with respect to 6, is supported on the one hand in the bush 11 and on the other hand in the spring receiver 23. This spring receiver 23 is snap-fitted onto the piston 16. As a result, the piston 16 is pressed against the inside of the tappet 9, so that the roller 21 is always brought into contact with the running surface 24 of the cam ring 13.

A safety ring 25 made of a thin metal plate and manufactured by squeezing and punching is attached to a snap ring 27 using a snap ring 27.
6 and has a plurality of fingers 28. These fingers 28 are oriented in the axial direction of the slide 12. A slit 29 is provided in the end surface of the hollow cylinder 20 of the tappet 9 parallel to the stroke direction, and a total of four openings 30 are provided in the end surface of the bush 11 as follows. That is, the respective apertures 30 are aligned with the slits 29 so that the fingers 28 of the safety ring 25 engage through the apertures 30 and into the slits 29.

A plurality of metering holes 31 are provided in the bushing 11 in the radial direction. Each of the supply grooves 33 in the slider 12 has one
Two metering holes 31 are connected to the stroke chamber 32 of the neck hole 8.

Similarly, the distribution groove 33' in the slider 12 in turn connects the stroke chamber 32 to the branch passage 38. This branch passage 38 is connected to an injection nozzle (not shown).

FIG. 3 shows a deflection ring 36 fitted into the ring groove 35 of the bushing 11.

This deflection ring 36 consists of two identical ring halves 37. Each individual ring half has an inwardly directed hook 39 and an outwardly directed hook 40. The ring halves 37 are engageable with each other with both hooks.

The deflection ring 46, which is only partially shown in FIG. 4, consists of two ring halves 47 and 48. Both hooks 50 of one ring half 47 are directed radially outwards, and both hooks 49 of the other ring half 48 are directed radially inwardly. so that both ring halves 47,48 also engage each other to form the deflection ring 46.

:1 The tappet 89 in FIG. 5 is the bottom 78 with the groove 19.
and a hollow cylindrical wall portion 80. This wall part 8
Two elongated holes 79 are formed in two locations facing each other in the diametrical direction within the 0, and the vertical axes of the individual elongated holes 79 are oriented in the stroke direction.

[Brief explanation of drawings]

Figure 1 shows a fuel injection pump according to the present invention at 1-1 in Figure 2.
2 shows the discharge position of the fuel injection pump in the axial direction along line II-II in FIG.
Figure 3 is a cross-sectional view of the range of the deflection ring taken along line 1-111 in Figure 2, Figure 4 is a partial view of a modified embodiment of the deflection ring, FIG. 5 is a perspective view of a tappet with an elongated hole. 8.17...hole, 9.89...tappet, 10...sleeve, 11...bushing, 12...slider, ]3
・Cam ring, 14...Cam, 15...Flange, 16...Piston, 18.78...Bottom, 19.
・Groove, 20・, Hollow cylinder, 21...Roller, 22
...Coil spring, 23...Spring receiver, 24...Running surface, 25...Safety ring, 26...Zess, 27...
Snap ring, 28. Finger, 29... Slit, 30... Opening hole, 31... Metering hole, 32... Stroke chamber, 33... Supply groove, 33'... Distribution groove, 34 ...
Inner chamber, 35...Link groove, 36.46...Deflection ring, 37.47.48...Ring half part, 38...
Branch passage, 39.40, 49.50... Hook, 79
...Long hole, 80...Wall part

Claims (1)

[Scope of Claims] ■. It has a rotating fuel distributor that distributes fuel to the injection nozzle and a cam ring, and each of the inwardly directed cams of the cam ring is loaded with a roller barb. In the version in which the pump stroke is imparted by a relative rotary movement to at least one piston guided radially in the Bonzo casing via tappets, the individual Yuhata (9) connects to the bottom (18). A hole (having a hollow cylinder (20) and guiding the piston (16)
8), and a groove (19) for fixing the roller (21) in position is provided on the outside of the bottom (18). (17
) A spring (22) arranged inside the tappet (9) is guided by a spring receiver (2) fixed to the piston (16).
3) The fuel injection pump is characterized in that the piston (16) is pressed against the inner wall of the bottom (18) of the tappet (9) via the tappet (9). 2. A safety ring (25) is provided which has a plurality of axial fingers (28) and is fixed to the pump casing, the hollow cylinder') (20) of the tappet (9)
are provided with slits (29) and the pump casing is provided with one aperture (29) in each case aligned with the slit (29).
30) and the fingers (28) are engaged through these apertures (30) and into the slits (29). injection pump. 3. Fuel injection pump according to claim 2, wherein the safety ring (25) rests in its active position on the boss (26) of the pump casing. 4. A fuel injection pump according to claim 2 or 3, wherein the safety ring (25) consists of a thin metal plate and is manufactured by squeeze punching. 5. Groove (19) at the bottom (18) of Yuhata (9)
) is a circular surface portion having the same radius as the roller (21), and the depth of the groove (19) is larger than the radius of the circular surface. The fuel injection pump according to any one of the following items. 6. Any one of claims 1 to 5, wherein the spring receiver (23) is snap-fitted on the outer circumferential surface of the piston (16) and close to the bottom (18) of the tappet (9). Fuel injection pumps as described in Section 1. 7. A plurality of metering holes (31) are provided in the pump casing in the radial direction l), and these metering holes (31) are connected to the stroke chamber' through the supply groove (33) of the slider (12). (
32) is connected to the inner chamber (34) of the pump, and a ring groove (35) is connected to the metering hole (34) on the outer periphery of the pump casing.
1), with individual metering holes (31
) is larger than the width of the ring groove (35), and the deflection ring (36; 46) assembled from one, one, two ring halves (37:47.48) is attached to the ring groove (35). ) A fuel injection pump according to any one of claims 1 to 6, which is fitted in a fuel injection pump. 8. Both ends of the individual ring halves (37; 47, 48) of the deflection ring (36; 46) are hook-shaped in diametrical section, so that both ring halves Fuel injection pump 09 according to claim 7, in which the split portions are adapted to be engaged with each other, one hook (40) radially outwards and the other hook (3
Claim 7, characterized in that both ring halves (37) are of the same shape, at least in the area of the hooks (39, 40), so that the ring halves (9) point radially inwards. The fuel injection pump according to item 8 or item 8. 10. Both hooks (5) of one ring half (47)
9. Fuel injection pump according to claim 8, wherein the hooks (49) of the other ring half (48) are directed inwardly. 11. Groove is long hole (79) in Tabetsu (89)
The elongated holes (79) are formed at locations facing each other in the diametrical direction, and the longitudinal axis of the elongated holes (79) is parallel to the stroke direction. Fuel injection pump as described in .