DE8911302U1 - Unit for pumping fuel from the storage tank of a motor vehicle to its internal combustion engine - Google Patents

Description

I ■····· Il Il · · · ·

R.22951
20.9.1989 Sa/Kc

ROBERT BOSCH GMBH, 7000 Stuttgart 10

Unit for pumping fuel from the storage tank of a motor vehicle to its fuel tank: * ^; ne_

State of the art

The invention relates to a conveying unit according to the preamble of the main claim. Such a conveying unit is already known (US-PS 44 93 620) in which the radial extension of the wall arranged in the central area of the impeller corresponds to the radial extension of the blades. Such a construction of the conveying unit is complex and therefore requires increased costs.

Advantages of the invention

The conveyor unit according to the invention with the characterizing features of the main claim has the advantage that it is simpler and therefore more cost-effective to manufacture.

The measures listed in the subclaims allow advantageous further developments and improvements of the conveying unit specified in the main claim. It is particularly advantageous to connect the free ends of the blades with a ring. This ensures that the entire internal leakage of the

II·· · I * ■

- 2 - 22951

Pump flows inwards between the impeller faces and the opposite faces of a chamber wall to the pump centre or outwards via the outer ring on the turbine wheel, so that only the two axial gaps have to be kept very small due to the higher tolerance. The radial gap present in the known pumping unit is of secondary importance if the impeller blades are connected at their free ends by the ring. This means that the tight tolerances required up to now on the outer diameter of the impeller and on the inner diameter of the pump housing as well as the required concentricity of the housing and impeller can be handled more generously. Furthermore, the turbine wheel with the outer ring is easier to control in terms of production technology, since it is practically no longer possible for the blades to break off. All of this leads to considerable cost savings in the manufacture of parts and in the assembly of the pump.

drawing

Embodiments of the invention are shown in the drawings and explained in more detail in the following description. Figure 1 shows a delivery unit according to the invention, in the area of the pump sectioned longitudinally, Figure 2 shows a detail of a first embodiment of the invention, marked II in Figure 1, in an enlarged view, Figure 3 shows the detail according to Figure 2, in another embodiment of the invention, Figure 4 shows a cross section through an impeller belonging to the pump, along the line IV-IV in Figure 1, in an enlarged view, the impeller being designed according to Figure 3 and Figure 5 shows the contour of a wall connecting the blades of the pump impeller in its circumferential direction, according to a detail marked V in Figure 2, in an enlarged view.

t » *· I t * t · · · ■·· , ti &igr; · · · «■■III Il » t «I «I

- 3 - 22951

Description of the embodiments

A unit 10 shown in Figure 1 is used to deliver fuel from a storage tank (not shown) to the internal combustion engine of a motor vehicle (also not shown). The fuel delivery unit has a flow pump 12, the impeller 14 of which is connected in a rotationally locked manner by a shaft 16 driven by an electric drive motor (not shown). The impeller 14 sits on a bearing pin 18 and is arranged in a so-called pump chamber which - viewed in the axial direction of the impeller 14 - is delimited on both sides by walls 20 and 22. The bearing pin 18 is arranged on the wall 20. The wall 22 has a bearing point 24 for the drive shaft 16;.uf. During operation of the delivery unit 10, the flow pump 12 sucks in fuel through a suction nozzle 26 and presses this medium through a pump outlet 28 in the wall 2? into a space 30 in which the electric motor (not shown) is housed. From there, the fuel is supplied to the internal combustion engine via an outlet or pressure connection 32. Since both the flow pump 12 and the electric motor (not shown) are housed in a common housing 34, which is provided with a suction connection ze and a pressure connection 32 and the fuel thus flows through the entire delivery unit 10, the fuel delivery unit forms part of the delivery line from the storage tank to the internal combustion engine.

As can be seen from Figure 4, the impeller 14 of the flow pump 12 has a disk-shaped central region 34 which is provided with a central bearing bush 36 in which the bearing pin 18 of the wall 20 is mounted. The impeller 14 or its central region 34 has a plurality of radial vanes 38 which are connected to one another at their free ends facing away from the central region 34 by a circumferential ring 40.

- 4 - 22951

As Figure 4 further shows, the wings 38 are in the circumferential direction of the ',i; impeller 14 are arranged at a distance from each other. From Figure 3 i\

it can be seen that adjacent wings 38 are connected to one another by a wall 42 which is arranged on the ring 40. ·

The arrangement of the wall 42 is such that it is located in the middle of the impeller 14 in relation to the thickness 44 of the impeller 14. There, the wall extends in the circumferential direction from one vane 38 to the other vanes 38 adjacent to it. The radial extension 46 of the wall is smaller than the radial extension 48 of the vanes 38. It is also clear that the thickness 49 of the wall 42 measured in the axial direction of the impeller 14 is smaller than the thickness 44 of the impeller between its end faces 52 and 54.

All of this also applies to another embodiment of the invention shown in Figure 2. In this embodiment, however, the wall 142 is arranged on the central region 34 of the impeller 14. In both embodiments, there is a passage 50 between the free end of the wall 42 or 142, which in the case of the embodiment ^:

according to Figure 3 by the central region 34 and in the embodiment according to Figure 4 by the outer ring 140.

As already mentioned above, the impeller is arranged in a so-called pump chamber, which is essentially circular-cylindrical. The two wall surfaces 56, 58 of the walls 20, 22 facing the end faces 52, 54 of the impeller each have a groove-like conveying channel 60, 62. The two conveying channels 60, 62 are opposite one another when viewed in the axial direction of the impeller, ■,

wherein the conveying channels 60, 62 have a semicircular cross-section ^;

The groove base 64 of the conveying channels 60, 62 is in contact with the

freely into the foot area 66 of the wall 42 or 142. The semicircular shape of the groove base 64 of the conveying grooves 60 is continued in the foot area 66 of the ?. wall 42 over about 90 degrees. This arrangement is ; in both designs, i.e. both according to Figure 2 and according to ;

- 5 - 22951

! Figure 3, provided. The semicircular cross-section of the conveyor channels 60

or 62 is thus continued seamlessly along the wall 42 on both sides of the wall 42 or 142. This curvature at the foot region 66 of the wall 42 is designated 68 in Figure 5. A flat wall section 70 adjoins each of these two foot curvatures 68 and is aligned in such a way that the two flat wall sections 70 converge in their radial ^extension , starting from the curvatures 68. The two flat wall sections 70 are connected to one another at their ends facing away from the foot curvatures 68 by a curvature 72 extending approximately over 180 degrees. The curvature 72 has a radius whose size is half the distance 74 between the two ends of the flat wall sections 70 facing away from the foot curvatures 68.

Claims (9)

R. 22951 20.9.1989 Sa/Kc ROBERT BOSCH GMBH, 7000 Stuttgart 10 Claims 1. Unit for conveying fuel from the storage tank of a motor vehicle to its internal combustion engine, with a flow pump, the essentially disk-shaped impeller has at least approximately radially aligned vanes arranged at a distance from one another in the circumferential direction, and between the vanes, viewed in the axial direction of the impeller in the central region between the two impeller end faces, a wall extends in the circumferential direction of the impeller, the smallest thickness of which, measured in the axial direction, is smaller than the thickness of the impeller between its end faces, characterized in that the radial extension (46) of the wall (42 or 142) is smaller than the radial extension (48) of the vanes (38). 2. Unit according to claim 1, characterized in that the free ends of the wings (38) are connected to one another by a ring (40 or 140). 3. Unit according to claim 1/ characterized in that the wall (142) is arranged on the central region (34) of the impeller carrying the blades (38). - 2 - 22951 4. Unit according to claim 2, characterized in that the hand
(42) is arranged on the ring (40). 5. Unit according to one of claims 1 to 4, in which the impeller in
an essentially circular cylindrical indrilled dot matrix and in the two, facing the front surfaces of the impeller % Stirüzlilühsä each chamber has a groove-like conveying channel % and the bftüefe £°£>x eis r channel e in the axial direction of the runningYauea t~ seen eis^n-?sr gec*»nüberliegen, whereby the conveyor channels i-inan half- I circular cross-section, characterized in that the I Groove base (64) of the conveyor channels (60, 62) smoothly into the foot area }■ (66) of the wall (42 or 142) and extends there over about 90 degrees I extends. | 6. Unit according to claim 5, characterized in that the At the end of each foot curve (64) of the hand (42 or 142) there is an i flat hand section (70) connects. : 7. Unit according to claim 6, characterized in that the flat
Hand sections (70) converge in their radial extension. 8. Unit according to one of claims 6 or 7, characterized in that the two flat hand sections (70) are
The ends facing away from the foot bends (68) are connected to one another without any joints by a bend (72). 9. Unit according to claim 8, characterized in that the
Curvature (72) has a radius whose (size is half of the
distance (74) with which the two feet are separated from the curvature
(68) opposite ends of the flat wall sections (70) from each other
condition.