EP0724921B1 - Tubular housing, in particular for a pump - Google Patents

Abstract

The housing is in the form of a cylindrical tube which has stepped bores at both ends in which bearing covers, e.g. a drive motor can be mounted. The housing is made by deep drawing. The stepped bores at either end are formed with stepped mandrel (13) which is forced into the ends of the tube. The flanges (9) which are formed by the mandrel are folded down against the outside diameter of the part of the mandrel which has the layer diameter.

Description

The invention relates to a method for producing a tubular Housing for pumps, motors and the like, in particular Fuel pump housing, on the inner wall for tight mounting e.g. a bearing plate of a pump motor, the inside diameter of the Enlarging step with constant outer diameter is trained.

Fuel pumps, but also other engines, are often made in one piece tubular housings that represent open cylinders on both sides, so that the pump parts to be accommodated in the housing, such as a Pump cylinder, a valve block, spring elements and a motor, as well as electrical Connections, fluid lines and mechanical connections easily can be introduced and fixed. The known tubular Housing on its inner wall for tight mounting, for example a bearing plate of a pump cylinder has a gradation on both open sides on. Pump housings of this type are made from welded, cut to length Pipe manufactured, with a subsequent machining a step is formed on both sides and the desired surface qualities and dimensions are manufactured. This is a big one Manufacturing costs connected, which in a significant way, the economy and marketability of such pump housing. Is technical disadvantageous that the welded design of the housing is not uncommon Leaks occur and the reject is enlarged. Also are the accuracies that can be achieved through subsequent machining as well as shape and position tolerances in need of improvement, for example from this it is evident that the desired tightness can only produce the required edge radius of the step by turning if Turrets in new condition can be used. The double function of the steps, namely mounting and tightness of the pump parts attached to it guarantee is only through complex processing and testing ensure.

In summary, it can be stated that the known housing and the processes for their production need technical and economic improvement are because of the drawbacks that come with use welded pipe and subsequent machining, for which a large number of successive processing steps have been carried out must be and high machine costs are required.

In view of this prior art, the invention is based on the object , while avoiding the disadvantages mentioned, of specifying a method with which an improved tubular housing for pumps, motors and the like, in particular fuel pumps, can be produced in a simple manner without machining.

The task is, based on the general procedure, solved according to the invention in that in a first Process stage from a metal blank by deep drawing or deep pressing in several steps a cup-shaped hollow body is generated that the Hollow body in a second process step on its free edge is expanded on the outside and the bottom of the pot is removed by one on both sides open hollow cylinder provide that in the extension an internal mandrel is used, the shape, dimensioning and surface of the chipless stage to be created is adjusted, and that the stage on the inner wall of the Hollow cylinder by ironing in several steps over the inner mandrel is produced and finally the inner mandrel is removed and the housing is cut to length.

This ensures that with the same outer diameter throughout an extremely simple and extremely precise internal step Surface quality can be produced without machining and For example, there are no problems in the preferred one Embodiment desired inner radius of R <0.2mm and one Edge chamfering at an angle of approximately 30 ° without an additional processing step adjust. That by the inventive method of a deep-drawn part manufactured pump housing brings a great economic advantage because the parts costs are only a third compared to the state of the art amount, the technical quality is significantly improved because of lack Leakages should not be expected and the Manufacturing accuracy is increased.

Preferably, the second open side of the Hollow cylinder expanded and a further gradation on the inner wall of the Hollow cylinder by ironing in several steps over the inner mandrel manufactured.

Advantageously, a sufficient one is just in the expansion area Amount of material provided via the subsequent ironing to the Gradation in the desired length and wall thickness without further processing to be able to produce, with a degree of deformation of about 50% becomes. The extension is preferably V-shaped, but it is noted that rectangular widening is also possible in principle.

The deep-drawn part produced using the method according to the invention is a cylinder open on both sides, which is open at a predetermined distance from each Page has the gradation produced without cutting. With the same The outer diameter is reduced in the gradation range Wall thickness with an enlarged inner diameter compared to the central part of the housing. It is advantageously achieved that the shape and Positional tolerances are smaller, the roughness depths that can be achieved are smaller through the production a material solidification is achieved that Pump housing less sensitive to damage during handling especially in the galvanic aftertreatment or during transport, makes.

Fig. 1

ein Kraftstoffpumpengehäuse im Schnitt,

Fig. 2

einen vergrößerten Ausschnitt "Y" des Kraftstoffpumpen-Gehäuses der Fig. 1,

Fig. 3

einen vergrößerten Ausschnitt "X" des Kraftstoffpumpen-Gehäuses der Fig. 1,

Fig. 4

die stufenweise Herstellung eines Kraftstoffpumpen-Gehäuses gemäß Fig. 1 in Einzelansichten Fig. 4/1 bis Fig. 4/8, schematisch.

Further details, preferred features and advantages of the subject matter of the invention result from the following description of the accompanying drawing, in which a pump housing and various process stages for its manufacture are shown schematically. The drawing shows:

Fig. 1

a fuel pump housing in section,

Fig. 2

2 shows an enlarged section "Y" of the fuel pump housing of FIG. 1,

Fig. 3

2 shows an enlarged section “X” of the fuel pump housing of FIG. 1,

Fig. 4

the gradual manufacture of a fuel pump housing according to FIG. 1 in individual views Fig. 4/1 to Fig. 4/8, schematically.

The tubular housing 1 of a fuel pump shown in FIGS. 1 to 3 of the drawing represents a hollow cylinder of circular cross-section which is open on both sides and has an identical outer diameter D _A throughout. The housing 1 consists of a central part 2, which merges on both sides into a gradation area 3 or 4, which is drawn in an enlarged representation in FIGS. 3 and 4 of the drawing. The inner diameter D _{I of} the central area increases in the gradation areas 3 and 4 to an average value D _Z lying between D _A and D _I , the wall thickness in the gradation areas 3 and 4 correspondingly being reduced to approximately half the wall thickness of the central part 2 .

Figures 2 and 3 with the details Y and X in an enlarged view show the gradation areas 3 and 4 and particularly illustrate that the steps 5 provided adjacent to the open sides of the case 1 and 6 worked out at right angles from the inner wall of the housing 1 are, with an inner radius R 0.2max must be observed in order to be in the finished state at the levels 5, 6 adjacent and pressed end shields for Keep fuel pump parts liquid-tight without additional sealants.

It can also be seen that the transition edge to the central part 2 in one Angle of 30 ° is chamfered.

The manufacture of the housing 1 is carried out according to FIG. 4 of the drawing in different ways Procedural steps. This is based on a metal blank 7, so a flat circular sheet metal part, from which by application a deep-drawn hollow body 8 as the forming technique is generated as shown in Fig. 4/1. The deep drawing is in itself known way in such a way that by means of a preceding stamp and a drawing ring, the blank 7 is pulled and in this way a vessel is formed, whereby during the deep drawing the blank diameter - as shown in the drawing - steadily reduced from the initial diameter and reaches the punch diameter towards the end of the drawing process. The Dragging is done in several steps, with this process being done by Fig. 4/2 is clarified.

In a next stage of the process, the drawing is then shown in FIG. 4/3 the free edge of the pot-shaped hollow body 8 extends outwards (Antulpen), where in the preferred embodiment according to the drawing V-shape for the antulpung / extension 9 is selected. Then the Pot bottom 10 removed by punching around a sleeve 11 open on both sides 4/4 of the drawing. One can assume that through this deep-drawing process in several stages up to this process step the material thickness does not change on average and therefore the The surface of the exit blank 7 and the sleeve 11 are approximately the same size. Due to the deformation, the material has already solidified surrender.

The further processing now takes place in the forming process of deep-drawing in a further step, the sleeve 11, which is pulled forward in the stop, being used as the starting shape instead of the flat cut. The aim here is to form stages 5 and 6 in a simple manner, the drawing part thereby being brought to its final length at the same time. The process of deep drawing in continuous blow is known as such and is also referred to as ironing, which is preferably carried out in several steps. An inner mandrel 12 is inserted into the antulpung 9 according to FIG. 4/5 of the drawing from below or the sleeve 11 is placed over such an inner mandrel. This is adapted in shape, dimensioning and surface to the level 5 or 6 to be produced without cutting and thus has a pin 13 projecting into the sleeve 11 and a stamp part 14. The pin 13 has an outer diameter which is matched to the inner diameter D _{I of} the sleeve 11, while the stamp part 14 has a diameter which corresponds to the inner diameter D _Z in the graded area of the finished housing 1. The shape, dimensions and surface of the inner mandrel 12 are matched to the gradation areas 3 and 4 to be produced in the subsequent drawing process. With a reduction, not shown, the further forming is now carried out in several stages. Fig. 4/6 shows the result. The step 5 now formed on one side of the sleeve 11 can be seen.

To also the second gradation 6 on the opposite side of the sleeve 11, there is a repetition of the process steps described above Antulpung 15 made in a V-shape and the ironing process 4/7 repeated according to the finished housing Fig. 4/8 produce which on both of its open sides the desired Gradation areas 3 and 4 according to FIG. 1 of the drawing.

It goes without saying and therefore not described in detail that the one Work step in gradual forming achievable diameter decreases depending on the material, the lubrication, the tool design and whether the material was annealed after the attack or Not. Although in the above description of a round plate made of metal / steel it is also possible to manufacture the housing from plastic by mechanical deep drawing. However, what does not fall under the scope of claim 1.

Reference list

1

casing

2nd

Central part

3rd

Gradation range

4th

Gradation range

5

step

6

step

7

Round blank

8th

pot-shaped hollow body

9

Enlargement or antulpung

10th

Pot bottom

11

Sleeve

12th

Internal mandrel

13

Cones

14

Stamp part

15

Enlargement / Antulpung

D _I

Inside diameter

D _A

outer diameter

D _Z

Gradation range

R

Inner radius

Claims (4)

1. Method of manufacturing a tubular housing for pumps, motors and the like, especially a fuel pump housing, on the inner wall of which there is formed, for the tight fitting e.g. of a bearing plate of a pump motor, a step (5 or 6) enlarging the inner diameter (D_I) of the housing (1) whilst the outer diameter (D_A) remains the same,
   characterised in that,
   in a first method step, a pot-shaped hollow body (8) is produced from a circular metal blank (7) by deep-drawing or deep-pressing in a plurality of steps, in that the hollow body (8), in a second method step, is extended towards the outside on its free edge and the pot base (10) is removed, in order to make available a hollow cylinder (11) open on both sides, in that there is inserted into the enlargement (9) an internal mandrel (12) which is matched in shape, dimensions and surface to the step (5) which is to be provided without cutting, and in that the step (5) is produced on the inner wall of the hollow cylinder (11) by ironing in a plurality of steps over the internal mandrel (12) and the internal mandrel (12) is finally removed and the housing (1), if necessary, cut to length.
2. Method according to claim 1, characterised in that the second open side of the hollow cylinder (sleeve 11) is also enlarged (15) and a second graduation (6) is formed on the inner wall of the hollow cylinder by ironing in a plurality of steps over the internal mandrel (12).
3. Method according to claim 1 and 2, characterised in that in the region of the enlargements (9 or 15) just a sufficient amount of material is made available for the subsequent ironing to produce the graduation (5 or 6) in the desired length and wall thickness without further processing, a degree of deformation of roughly 50% being set.
4. Method according to one of claims 1 to 3, characterised in that the enlargement (9 or 15) is configured V-shaped.

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