GB2041448A

GB2041448A - Fuel pump unit

Info

Publication number: GB2041448A
Application number: GB8004827A
Authority: GB
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1979-02-17
Filing date: 1980-02-13
Publication date: 1980-09-10
Also published as: JPS55112853A; JPH0174390U; DE2906224A1

Abstract

The fuel pump unit is suitable for fitting in a fuel tank and comprises a side-channel pump and an electric motor which drives the pump, the pump and the electric motor being arranged in tandem. To simplify construction, the actual housing for the unit is omitted and an inner intermediate flange member 8 of the pump 1 externally contiguous therewith is inserted into one end of a pole tube 5 carrying the magnets 6 for the electric motor 2, a connection cover 7 having a pressure connection 4 being inserted into the other end of the pole tube. Preferably, a connection cover 10 at the suction side is secured to the intermediate flange 8. The pump has a side-channel impeller 9 which is open towards both axial sides and the pump also has an axial gas venting hole 13. The pump parts 8, 9, 10 can be injection moulded from plastics material and reinforced with glass fibre, the pump being a preassembled unit. <IMAGE>

Description

SPECIFICATION Fuel feed unit The present invention relates to a fuel feed unit for use in a motor vehicle.

A large number of fuel feed pumps are known, the entire unit, comprising a driving electric motor and a single stage or multistage pump system, frequently being accommodated in a common, cup-shaped housing.

The two main parts, namely the pump and the motor, are usually arranged axially one behind the other within the housing i.e. in tandem. It is customary to arrange the pump system immediately adjacent to a bottom wall which also forms the suction connection piece and which, if required, is integrally connected to the housing, the electric motor then being contiguous with the pump system. The rotary elements of the two parts can be mounted on a common shaft. Alternatively, it is also possible to arrange the rotatable pump part on a fixed axle by means of bearing bushes, that is to say, the impeller in a side channel pump or the grooved disc in the case of a roller-cell pump, to mention only two of the most common pumps used for feeding fuel in motor vehicles.The drive from the rotating armature of the electric motor, which can either be arranged on a fixed axle by means of a hollow shaft or mounted on a rotatable shaft jour nalled in bearings at each end, is effected by way of a driver connection.

The known fuel feed pumps are of relatively complicated construction and require a large number of individual components which have to be mounted and secured in an accurate relationship with one another. Problems in the feeding of hot petrol can also occur in the known pumps and have to be counted.

Thus, there is a need for a fuel feed pump which is of simple construction and which is thus inexpensive and which is thus inexpensive and which is located as a so-called wet electric fuel pump in the fuel, that is to say, it is located within the fuel tank and feeds the fuel by means of an independently driven pump.

According to the present invention there is provided a fuel feed unit comprising a sidechannel pump and an electric motor arranged to drive the pump, the pump and motor being arranged in tandem so that fuel delivered under pressure by the pump flows through the motor, one part of the pump being inserted in one end of a pole tube which carries the magnets for the motor, and a connection cover with a pressure feed connection, being inserted into the other end of the pole tube.

A fuel feed unit in accordance with the present invention, has the advantage that it is of particularly simple and uncomplicated construction and the entire system comprises only a few individual parts. The ease of assembly is particularly advantageous since specific components, particularly the pump, are in the form of pre-assemblable units. An operationally reliable and inexpensive unit is provided combining components, a large number of which are made of a plastics material, and by designing the unit to have small external dimensions.

A special advantage is that problems resulting from feeding hot petrol, can be reliably countered by the special design of the components in the region of the pump; The effective delivery of hot petrol is also rendered possible by the use of an open sidechannel impeller which is embraced at each side by a cover flange having a side channel.

The individual components are connected by overlapping flanges or by mutual formlocking penetration of edge elements.

The present invention will now be further described, by way of example, with reference to the accompanying drawing in which a lateral section through and electric fuel pump in accordance with the invention, is shown.

The illustrated embodiment of the present invention comprises a wet electric fuel pump of the side-channel type, the pump or its rotary part being driven by an attached d.c.

motor having permanent magnets.

The electric fuel pump unit illustrated in the drawing comprises a pump 1 and an electric motor 2 which drives the latter, the pump 1 and the electric motor 2 being arranged axially one behind the other i.e. in tandem and the pump 1 being arranged upstream of the electric motor in the direction in which the fuel flows from a suction connection piece 3 to a pressure connection piece 4.

In contrast to the conventional construction in which all the components are surrounded by a housing, a respective end flange 7 and 8 is inserted or pressed into each end of the central pole tube 5 for mounting the magnets 6 of the electric motor and also provides a magnetic flux return path, the end flanges being held at these locations by form-locking connection means.

The actual pump part 1 comprises three components, namely the end flange 8 which has already been mentioned and which can also be regarded as the basic part or intermediate flange member, for the side-channel pump, the actual impeller of the side-channel pump, and an external connection cover 1 0.

Preferably, the parts 8, 9 and 10 are made from a plastics material and are preferable injection moulded plastics members reinforced with glass fibre. The suction connection piece 3 is preferably integrally injection-moulded with the connection cover 1 0. Furthermore, the connection cover has a first side channel 11, a suction slot 1 2 into which the suction connection piece 3 merges, and an axial venting bore 1 3 for the side channel 11, which venting bore is disposed in the connection cover 10 and is located diammetrically opposite the suction connection piece 3 and serves for the axial discharge of gas.

The connection cover is seated against a step or shoulder 14 of the intermediate flange 8 and can be pressed into this position, the connection cover 10 is held against the shoulder of the intermediate flange by an inwardly directed flange 1 5 of a neck 1 6 of the intermediate flange. The connection cover 10 has one axial bearing for continuous shaft 1 6 which carries the armature 1 7 of the electric motor and which is held in a further axial bearing 1 8 in the oppositely located end flange 7.The axial bearing in the connection cover 10 is designated 1 9 and, in the simplest case, can be formed by a bearing ring 20 which has a specific axial extension and which is pressed into central recess 21 in the connection cover 1 0.

The impeller 9 of the side-channel pump, is held and mounted between the connection cover 10 and the intermediate flange 8 and is either mounted on the shaft 1 6 so as to be freely rotatable thereon or is splined thereto so as to be non-rotatable relative thereto. The impeller is however preferably axially displaceable and preference is given to the impeller being freely rotatably mounted. In the illustrated embodiment, the impeller is rotatably driven by way of a driver 22 of the armature 1 7 of the electric motor which engages a suitable recess 23 in the impeller 9.

The impeller 9 itself lies in a further stepped region 24 of the intermediate flange 8 and has around its periphery a closed rim 25 which axially seals the impeller relative to the intermediate flange 8 and the end connection cover 10. The impeller 9 is open towards both axial sides, since a second side channel 26 is located in the intermediate flange 8 together with the pressure opening (not illustrated in the drawing).

The armature of the electric motor 2 can be of conventional construction, it being rigidly pressed onto the shaft 16, and the driver 22 for the impeller 9 is formed by a part of an extruded jacket of coating of the armature.

The intermediate flange 8 has external stepped shoulders 27, 27a up to which the flange 8 is inserted into the pole tube 5 until the pole tube 5 comes into abutment thereagainst. The intermediate flange 8, and thus the pump parts 8, 9 and 10, can be connected to the pole tube 5 in any optional manner, though preferably by forming tongues on the intermediate flange 8 by ultrasonic action such they fit into circular cut-out portions in the pole tube and are anchored therein. Thus, an absolutely rigid connection is obtained which is also required for the precision mounting of the armature and impellet shaft 16.

A further preferred feature of the present invention resides in the fact that magnet holders are formed, preferably injectionmoulded, on the intermediate flange 8. In conformity with the construction of the electric motor, two magnet holders 28 of wedgeshaped construction are injection moulded on the intermediate flange 8 and, as will be seen, are pressed radially inwardly by means of springs 29 (preferably corrugated springs) interposed between the outer region of flange 8 and the inner wall of the pole tube 5. Thus, the magnets are clamped and reliably held by the component forces which result from the radially inwardly directed pressure force and those forces which act in a circumferential direction.

In accordance with a further preferred design of the present invention, and in the course of combining components, the end flange of connection cover 7 at the pressure side is integrally formed with the brush holder to form a component with which the pressure connection piece 4 is also integrally formed.

The region of the brush holder is designated 30 in the drawing. The brush holders 31 with the brushes 32 are arranged diametrically opposite one another with respect to shaft 16, and the commutator 33 of the electric motor is interposed therebetween.

The armature is subjected to an axial force which pulls the armature towards the housing cover at the pressure side, as a result of a desired, slight offset of the magnets 6 relative to the armature laminations. The pressure of the armature on connection cover 7 is absorbed by a ball 37 located in a conical taper 34 of bearing bore 35 for the bearing 36 which supports shaft 16. The electrical connection pins, one of which is shown at 38, are held by extrusion coating preferably during manufacture of the connection cover 7 at the pressure side, or are pressed into the connection cover and secured by Christmas tree profiles. The general direction of flow of the fuel feed is shown by the arrows A, A', while the axial discharge of gas is shown by the arrow B.

The connection cover 7 at the pressure side is also inserted into the pole tube 5.up to an external shoulder 39 and is held therein in a form-locking manner by material deformation by, for example, pressing or punching or shearing sheet metal tabs of the pole tube into the material of the connection cover so as to hold the latter and the brush holder.

All the novel features described in the specification and in the following claims and illustrated in the drawing can be essential to the invention both individually and combined in any optional manner.

Claims

1. A fuel feed unit comprising a sidechannel pump and an electric motor arranged to drive the pump, the pump and motor being arranged in tandem so that fuel delivered under pressure by the pump flows through the motor, one part of the pump being inserted in one end of a pole tube which carries the magnets for the motor, and a connection cover with a pressure feed connection, being inserted into the other end of the pole tube.

2. A fuel feed unit as claimed in claim 1, in which the pump comprises three plastics material parts, a front connection cover an intermediate flange member and an impeller, the impeller being located between the front connection cover and the intermediate flange member, said parts being preassembled as a unit.

3. A fuel feed unit as claimed in claim 2, in which the plastics material parts are injection moulded from plastics material and reinforced with glass fibre.

4. A fuel unit as claimed in claim 2, 3 or 4 in which the front connection cover of the pump, has a suction slot merging into a suction connection piece, a first side channel and axial venting bore, and is held in a neck of the intermediate flange by an inwardly directed flange.

5. A fuel feed unit as claime in any one of claims 2, 3 or 4, in which the side-channel impeller arranged between the front connection cover and the intermediate flange member, is open at both axial sides and is held against a shoulder of the intermediate flange member.

6. A fuel feed unit as claimed in claim 4, in which the intermediate flange member has a second side channel located opposite the first side channel in the front connection cover, and a pressure opening which releases the delivered fuel under pressure into the interior of the electric motor.

7. A fuel feed unit as claimed in claim 6, in which the circumference of the side channel impeller has a closed rim for the purpose of axially sealing the side channel impeller in the intermediate flange member.

8. A fuel feed unit as claimed in any one of the claims 2 to 6, in which the intermediate flange member is inserted up to a shoulder thereof into the pole tube and is anchored in a form-locking manner by deformation of material.

9. A fuel feed unit as claimed in claim 8, in which for the purpose of anchoring the pump in the pole tube, tongues formed from the intermediate flange member of the pump by ultrasonic action, engage cut-away portions in the pole tube.

10. A fuel feed unit as claimed in claim 8 or 9, in which the front connection cover incorporates an axial bore provided with a bearing for a shaft on which the side channel impeller is held in addition to the armature of the electric motor.

11. A fuel feed unit as claimed in any one of the claims 2 to 10, in which wedge-shaped magnet holders are injection moulded onto the intermediate flange member of the pump for the purpose of holding the permanent magnets of the electric motor, and springs are arranged between the magnet holders and the interior wall of the pole tube and press the magnet holders radially inwardly such that the magnets are clamped by the forces acting in a circumferential direction.

1 2. A fuel feed unit as claimed in any one of the claims 1 to 11, in which a shaft journalled at one end in a bearing in the front connection cover and at the other end in a bearing of the connection cover at the pressure side, is rigidly pressed into the armature and has a driver, forming part of an extrusion coating of the armature, for driving a side channel impeller of the pump.

13. A fuel feed unit as claimed in any one of claims 1 to 12, in which a brush holder and the connection cover at the pressure side, form an integral component into which electrical connection pins are also pressed, which component is held in the pole tube by anchoring it thereto in a form-locking manner.

1 4. A fuel feed unit as claimed in any one of claims 1 to 13, in which for the purpose of absorbing an axial pull exerted by the armature of the motor, a ball located axially in front of an end of a shaft supporting the armature, is arranged in a conical taper of a shaft bearing located in the connection cover at the pressure side.

1 5. A fuel feed unit as claimed in claim 13, in which the electrical connection pins pressed into the connection cover are secured therein by means of a Christmas tree profile.

1 6. A fuel feed unit constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.