DE102004047601A1 - Fluid pump e.g. high-pressure fluid pump, for internal combustion engine, has extension in flow path leading from inlet to chamber and multifunction unit arranged in extension and including retaining section for retaining filter device - Google Patents

Abstract

The pump has a chamber (30) that is limited by a delivery unit. An extension (48) is available in a flow path leading from an inlet to chamber. A multifunction unit (68) is arranged in the extension and has a retaining section for retaining a filter device. The filter device has a sealing lip, which cooperates with a sealing area at a housing (40). The filter device is so arranged and formed that it covers a number of channels.

Description

The The invention relates to a fluid pump, in particular a high-pressure fuel pump, with a pump housing, an inlet, and a delivery room, which is limited by a movable conveyor becomes.

Such a fluid pump is out of the DE 195 39 885 A1 known and used for example in internal combustion engines with direct fuel injection. In such internal combustion engines, the fuel is compressed by the fluid pump to a high pressure and conveyed into a fuel rail. From this, the fuel passes under high pressure via fuel injectors directly into the combustion chambers of the internal combustion engine. The fluid pump sucks the fuel via an inlet and an inlet valve into a delivery chamber. This is limited by a reciprocating delivery piston.

Around To compensate for pressure fluctuations in a fuel line, the is connected to the inlet, a pressure damper is provided. For protection the moving parts within the fluid pump is further a filter device present, which in the introduced Fuel filters out existing impurities. This is usually in arranged a connection piece of the inlet.

task The present invention is a fluid pump of the above so-called type so that they on the one hand as possible has small dimensions and on the other hand, easy and inexpensive can be manufactured and assembled.

These Task is characterized in a fluid pump of the type mentioned by solved, that in one from the inlet to the delivery room leading flow An extension exists in which a multifunction element is arranged.

Advantages of invention

at the fluid pump according to the invention reduces the number of parts to be manufactured and assembled, by a multi-functional element is provided, which is therefore a Has a plurality of functions. These functions may include holding and / or positioning another element, it may be for Application of a holding force can be used, and / or it can an item from being damaged protect. By combining multiple functions into a single component are, the manufacture and assembly of the fluid pump are simplified. About that In addition, space is saved so that the fluid pump is smaller overall builds. The arrangement in an extension makes it possible to use the multifunction element sufficiently big too make the desired functions fulfill to be able to.

advantageous Further developments of the fluid pump according to the invention are specified in subclaims.

So For example, it is suggested that the multifunction element a holding portion for holding a filter device comprises. By the arrangement of the multi-functional element with the filter device in the extension of the flow path can build the filter device comparatively large, which is the flow resistance reduces and increases the efficiency of the fluid pump. On an inlet filter, for example in a connecting piece, can then be dispensed with. By the holder of the filter device through the multifunction element in the extension of the flow path can the filter device over it beyond independent designed from the position of a connecting piece and thus for several different types of fluid pump can be used.

Further the machining effort in the manufacture of the pump housing is reduced, because the interface of the filter device to the pump housing out is significantly simplified. This interface can generally as a flat surface be carried out without, for example, otherwise necessary countersinks. The same multifunctional element can vary greatly shaped filter devices, for example, oval, kidney-shaped, triangular, etc., possibly also very different layers and forms of towards enlargement and away from enlargement channels cover.

there the assembly effort is further simplified when the filter device integrated into the multifunction element. It is possible, for example, that the filter device in the form of a filter in the multi-functional element injected.

Further the filter device may have a sealing lip, which with a Sealing area on the pump housing cooperates. this makes possible the embodiment of a particularly simple sealing area on the pump housing, which further reduces the manufacturing costs of the fluid pump according to the invention.

The multi-functional element may further include a biasing portion biasing a filter device against the pump housing. This improves the seal between the filter device and the pump housing and increases the reliability of the fluid pump.

proposed Also, that the multifunction element is a protection section comprising, which in the region of a junction of the flow path at least partially limiting housing cover with a housing body of the pump housing is arranged so that it penetrates when establishing the connection of particles in the flow path prevented or at least reduced. Such a connection will for example, by soldering or welding produced. Here you can for example, sweat particles in the flow path reach, which during operation of the internal combustion engine, for example can jam in valve devices. Due to the inventive design the fluid pump is thus the reliability improved or at all the use of assembly processes such as welding allows.

Farther the multifunction element can have at least one positioning section comprising a pressure damper positioned at least in one room level. Possible, for example, the Use of a designed as a closed volume pressure damper (diaphragm damper), the for example, by the multifunction element within the extension can be centered. As a result, noises are reduced during operation and the full functionality of the pressure damper becomes ensured.

Is possible also that the multi-functional element comprises a support section on which a pressure damper supported, the support section Has spring properties. This allows the pressure damper with a predetermined force, for example against a housing area to apply, whereby the pressure damper securely held and at the assembly special adjustments are avoided. Furthermore allows this, a gas spring to use, which is subjected to an internal pressure.

The Multifunction part may be a sheet metal part or a plastic injection molded part. A sheet metal part offers certain advantages due to its elasticity, a plastic injection molded part is particularly inexpensive to produce.

Especially It is also advantageous if an attachment portion of the multifunction part a pin-like projection and a corresponding attachment portion of the pump housing comprise a corresponding recess. This will be the multifunction part across from the pump housing safely assigned or aligned in an easily assembled manner. In this case, the pin-like projection integral with the multifunction part be formed, or it may be a separate, the multifunction part act fixed part (screw or bolt). Of course it is it also possible that the peg-like projection on the pump housing and instead the recess is present at the multifunction part.

Further can a mounting portion of the multifunction part with a the extension cooperate at least partially limiting housing cover. This allows the multifunction part to be held with it and / or positioned and / or protected parts together with the housing cover vorzumontieren and then as an entire unit, for example, on a pump body of the pump housing to fix. As a result, the assembly is greatly facilitated.

In Further development is proposed that on the housing cover a connecting piece is attached. On the pump body of the pump housing are thus less cutting work required, what its production makes it easier and cheaper. At the same time, in this way the limited at least partially from the housing cover Extension automatically part of the flow path from the inlet to the delivery room out.

The Dimensions of the fluid pump according to the invention are then reduced when the housing cover in the attachment area of the connection piece to a housing body of the pump housing is retracted.

Further is used to protect and increase the Life of the filter device proposed that a filter fabric the filter device at least substantially parallel to a Baffle and / or is arranged at such a distance to a baffle that the flow rate of the fluid is limited thereby.

drawings

following become particularly preferred embodiments the present invention with reference to the accompanying Drawing closer explained. In the drawing show:

1 a schematic representation of an internal combustion engine with a high-pressure fluid pump;

2 a partial section through a first embodiment of the fluid pump of 1 ;

3 an enlarged detail view of the fluid pump of 2 ;

4 a representation similar 3 an alternative embodiment of a fluid pump;

5 a representation similar 3 a further modified embodiment of a fluid pump and

6 a partial section along the line VI-VI of 5 ,

description the embodiments

In 1 carries a fuel system of an internal combustion engine not shown in detail the reference numeral 10 , It includes a fuel tank 12 from which a prefeed pump 14 the fuel to a low pressure port of a high-pressure piston pump designed as a fluid pump 18 , in the 1 indicated by a dot-dash line promotes.

A high pressure connection 20 the fluid pump 18 is with a fuel rail 22 connected. In it is the one of the fluid pump 18 compressed fuel stored under high pressure. To the fuel rail 122 are several fuel injectors 24 connected to the fuel in their respective associated combustion chamber 26 inject directly.

This in 1 shown hydraulic diagram of the fluid pump 18 shows some of its essential components: this includes a delivery piston 28 which can be displaced by a drive shaft, not shown, in a reciprocating motion. He belongs to the limitation of a pumping room 30 , which has a switchable inlet valve 132 with the low pressure connection 16 and via an exhaust valve 34 with the high pressure connection 20 can be connected. In the flow path from the low-pressure connection 16 to the delivery room 30 down is in a flow path 36 a pressure damper 38 arranged. A filter device 88 , which will be discussed in more detail below, is fluidly between the inlet 16 and the controllable inlet valve 32 arranged to the fluid pump and in particular the inlet valve 32 to protect.

The inlet valve 32 can be used to adjust the flow rate of the fluid pump 18 be controlled. For this purpose, during a delivery stroke of the delivery piston 28 the inlet valve 32 forcibly opened so that the fuel is not going to the fuel rail 22 but back to the low pressure port 16 is encouraged. Among other things, this in the flow path 36 occurring pressure pulsations are from the pressure damper 38 smoothed.

How out 2 can be seen, includes the fluid pump 18 a pump housing 40 with a cylindrical housing body 42 and a housing cover arranged on its axial end side 44 , The housing body 42 is a rotating part, whereas the housing cover 44 is formed without cutting as sheet metal part, for example made of stainless steel sheet. On the housing cover 44 is attached to an inlet port, which is the low pressure port 16 forms. In the area of attachment of the inlet nozzle 16 is a floor 46 of the housing cover 44 to the housing body 42 pulled in.

The inlet nozzle 16 opens into a between the housing cover 44 and the housing body 42 formed extension 48 , which will be discussed in detail below. One in the housing body 42 existing channel 50 leads from the extension 48 in a manner not shown to the inlet valve 32 which is in 2 is not visible. On the housing body 42 is attached to an outlet, which is the high pressure port 20 forms.

The pressure damper 38 is within the extension 48 of the flow path 36 arranged and comprises two generally parallel to each other membranes 52a and 52b , These each have a central and provided with concentric beads spring section 54a respectively. 54b on, as well as a plan and circumferential edge section 56a respectively. 56b , The latter are at their radially outer free edge with each other in 58 welded. Between the two membranes 52a and 52b is a gas volume 60 locked in.

Between the edge section 56a of the pressure damper 38 and the floor 46 of the housing cover 44 is a pretensioner hood 62 arranged under bias. In this are several openings 64 present, which one between the Vorspann hood 62 and the housing cover 44 located annulus 65 with one between the membrane 52a and the pretension hood 62 located room 67 connect. Between the pressure damper 38 and a planar axial end surface 66 of the housing body 42 is within the extension 48 a multifunctional element 68 arranged, which is now with reference to 3 explained in detail:
The multifunction element 68 is referred to as such because it fulfills a plurality of very different functions. For example, it serves as a counter-biasing element for the preload hood 62 for positioning the pressure damper 38 , for holding a filter device designated in more detail below, for the protection of the extension 48 during assembly of the housing cover 44 on the housing body 42 , for centering the pressure damper 38 within the extension 48 , and for fixing the assembly 44 . 62 . 38 . 68 as a preassembled module.

This is the multifunction element 68 formed as a whole in plan view, round sheet metal part, with a radially outer clamping ring portion 70 , This works in a slight press fit with an inner lateral surface 72 of the housing cover 44 together. From the clamping ring section 70 extends radially inward, a spring portion 74 which is formed by a bend of substantially 180 °. The spring section 74 serves as an abutment for the pressure damper 38 , Its edge sections 56a and 56b So are between the Vorspann hood 62 and the spring section 74 of the multifunction part 68 jammed. About the circumference of the multifunction part 68 are distributed from the spring section 74 centering tabs 75 punched out, which is essentially in the axial direction to slightly above the two edge sections 56a and 56b are extended out. These centering straps serve to center the pressure damper 38 essentially centric within the extension 48 ,

From the spring section 74 extends radially inward a total in the cross-sectional plane of the multi-functional element 68 lying central section 76 , An opening 78 connects one between the axial end surface 66 and the multifunction element 68 located room 80 with one between the multifunction element 68 and the membrane 52b of the pressure damper 38 located room 82 , openings 84 in the transition region between the clamping ring section 70 and the spring section 74 connect the room 80 with the between the pretension hood 62 and the housing cover 44 existing space 65 ,

The central section 76 has an example produced by punching and forked holding portion 86 up, out of the plane of the central section 76 something to the axial end face 66 of the housing body 42 out bent ("notched") is. The holding section 86 serves to hold a filter device 88 which is a retaining ring made of an elastic material 90 and a filter screen 92 includes. The retaining ring 90 has in its outer circumferential surface a circumferential groove 94 in, in which the fork-shaped holding section 86 intervenes. The retaining ring 90 points to the axial end surface 66 towards a circumferential sealing lip 96 on, at the there forming a sealing area axial end face 66 under a certain bias is applied. This bias is on the one hand by the sealing lip 96 itself, on the other hand by the elasticity of a Vorspannabschnitts 98 scored, with which the holding section 86 with the actual central section 76 of the multifunction element 68 connected is.

The filter device 88 has in the in the 2 and 3 shown embodiment circular contour and is located in the region of the mouth of the channel 50 in the extension 48 , The diameter of the filter device 88 or of the filter screen 92 can be significantly larger than the diameter of the channel 50 what a high efficiency of the filter device 88 over the life of the fluid pump 18 allows. By a targeted arrangement or an arrangement at a certain distance of the filter device 88 to the pressure damper 38 the flow rate of the fuel through a filter fabric (not numbered) of the filter device 88 be limited. This protects the filter fabric from overloading.

For assembly, first the connection piece 16 on the housing cover 44 for example, fixed by welding. Then the pretension hood 62 inserted in the lid, on this the pressure damper 38 hung up, and finally the multifunction element 68 with the already pre-assembled filter device 88 in the housing cover 44 inserted. Due to the slight clamping seat of the clamping ring section 70 with the housing cover 44 is in this way the pressure damper 38 as well as the filter device 88 safe in the housing cover 44 held. In this case, the clamping force between the clamping ring section 70 and the housing cover 44 just just so high that the multifunction part 68 secure in the housing cover before installation 44 is held. Now the housing cover 44 on the axial end surface 66 of the housing body 42 put on and in 100 welded.

When pressing the housing cover 44 on the housing body 42 comes a free border 102 of the clamping ring section 70 of the multifunction part 68 in contact with the axial end surface 66 of the housing body 42 so that the multifunction element 68 further into the housing cover 44 is pushed in until the housing cover 44 on the housing body 42 is applied. This will be the pressure damper 38 safely between the spring section 74 of the multifunction element 68 and the pretension hood 62 braced. When making the weld 100 serves the clamping ring section 70 as apron-like protection portion, which is an intrusion of when making the weld 100 produced particles in the flow path (arrows 36 in 3 ) within the extension 48 prevented. Thus, the weld can 100 be performed as a welded seam, which is optimal for strength.

When the fluid pump 18 promotes the fuel flows through the low-pressure connection piece 16 in the room 65 , from there through the openings 64 in the room 63 , from there over the openings 84 in the room 80 , continue over the opening 78 in the room 82 , and about the filter device 88 finally in the canal 50 , In this way, the fluid pump 18 against dirt particles, for example from the upstream of the prefeed pump 14 to the high pressure pump 18 protected, with simultaneous effective damping of pressure pulsations in the flow path 36 ,

An alternative embodiment of a fluid pump 18 is in 4 shown. Here, as below, it applies that such elements and regions which have equivalent functions to previously described elements and regions bear the same reference numerals and are not explained again in detail.

At the in 4 The embodiment shown is the multifunction part 68 not manufactured as a sheet metal part, but as a plastic injection molded part. It fulfills the same functions as in the 2 and 3 shown sheet metal part. To be at the in 4 shown multifunction part 68 the filter device 88 secure to the axial end surface 66 of the housing body 42 to be able to press, is designed as a pin-like projection bolt 104 provided, which in a corresponding recess 106 in the axial end surface 66 of the housing body 42 engages in a press fit.

Incidentally, the pressing force with which the multifunction part 68 against the housing body 42 is pressed, mainly from the Vorspann hood 62 generated. For assembly, unlike the previous embodiment, the multi-functional part 68 over the bolt 104 in the housing body 42 attached. Then, the pressure damper 38 , the pretensioner hood 62 , and finally the case cover 44 appropriate. The latter is through the clamping ring section 70 of the multifunction part 68 centered.

The filter screen 92 is directly in the multifunction part 68 injected, thus integrally formed with this. A corresponding separate holding section with a retaining ring, etc., so is not required.

Another embodiment show the 5 and 6 , Here is the multifunction part 68 identical to that of the embodiment of 2 and 3 educated. However, on the housing cover 44 no inlet connection available. This is rather at an in 5 invisible location on the housing body 42 appropriate. The fluid connection from the inlet nozzle to the extension 48 takes place via a channel 108 which is in the room 80 between the multifunction part 68 and the axial end surface 66 of the housing body 42 empties.

From the filter device 88 out in the housing body 42 two channels 50a and 50b , The one leads to the in 5 not shown controlled inlet valve (reference numeral 32 in 6 ), the other directly to a room 31 the fluid pump 18 on the conveyor room 30 opposite side of a just in 1 explicitly drawn cylinder liner 33 lies. As in particular from 6 shows is the filter device 88 not circular in the present embodiment, but oval. Also possible are almost any other contours, such as a kidney-shaped contour.

Claims (15)

Fluid pump ( 18 ), in particular high-pressure fuel pump, with a pump housing ( 40 ), an inlet ( 16 ), and a delivery room ( 30 ), which is covered by a mobile 28 ), characterized in that in one of the inlet ( 16 ) to the delivery room ( 30 ) leading flow path ( 36 ) an extension ( 48 ), in which a multifunction element ( 68 ) is arranged. Fluid pump ( 18 ) according to claim 1, characterized in that the multifunctional element ( 68 ) a holding section ( 86 ) for holding a filter device ( 88 ). Fluid pump ( 18 ) according to claim 2, characterized in that the filter device ( 88 ) in the multifunction element ( 68 ) is integrated. Fluid pump ( 18 ) according to one of claims 2 or 3, characterized in that the filter device ( 88 ) a sealing lip ( 96 ) having a sealing area ( 66 ) on the pump housing ( 40 ) works together. Fluid pump ( 18 ) according to one of claims 2 to 4, characterized in that the filter device ( 88 ) is arranged and / or shaped to have a plurality of channels ( 50a . 50b ) covered. Fluid pump ( 18 ) according to one of the preceding claims, characterized in that the multifunctional element ( 68 ) a header section ( 98 ) comprising a filter device ( 88 ) against the pump housing ( 40 ). Fluid pump ( 18 ) according to one of the preceding claims, characterized in that the multifunctional element ( 68 ) a protection section ( 70 ), which in the region of a connection point ( 100 ) one the flow path ( 36 ) at least partially limiting housing cover ( 44 ) with a housing body ( 42 ) of the pump housing ( 40 ) is arranged in such a way that when establishing the connection ( 100 ) the penetration of particles into the flow path ( 36 ) prevented or at least reduced. Fluid pump ( 18 ) according to one of the preceding claims, characterized in that the Multifunctional element ( 68 ) at least one positioning section ( 75 ) comprising a pressure damper ( 38 ) positioned at least in a spatial plane. Fluid pump ( 18 ) according to one of the preceding claims, characterized in that the multifunctional element ( 68 ) a support section ( 74 ), to which a pressure damper ( 38 ) is supported, wherein the support section ( 74 ) Has spring properties. Fluid pump ( 18 ) according to one of the preceding claims, characterized in that the multifunction part ( 68 ) is a sheet metal part or a plastic injection molded part. Fluid pump ( 18 ) according to one of the preceding claims, characterized in that a fixing portion of the multifunction part ( 68 ) a pin-like projection ( 104 ) and a corresponding attachment portion of the pump housing ( 40 ) a corresponding recess ( 106 ). Fluid pump ( 18 ) according to one of the preceding claims, characterized in that a fixing section ( 70 ) of the multifunction part ( 68 ) with an extension ( 48 ) at least partially limiting housing cover ( 44 ) works together. Fluid pump ( 18 ) according to claim 12, characterized in that on the housing cover ( 44 ) a connecting piece ( 16 ) is attached. Fluid pump ( 18 ) according to claim 13, characterized in that the housing cover ( 44 ) in the area of attachment of the connecting piece ( 16 ) to a housing body ( 42 ) of the pump housing ( 40 ) is withdrawn. Fluid pump ( 18 ) according to claims 2 and 8, characterized in that a filter fabric of the filter device ( 88 ) at least substantially parallel to a baffle surface ( 38 ) and / or at such a distance to a baffle surface ( 38 ) is arranged, that the flow velocity of the fluid is limited thereby.