DE102016225954A1 - High-pressure pump, in particular for a fuel injection system, with integrated suction valve - Google Patents

Abstract

The invention relates to a high pressure pump for a fuel injection system, comprising a housing part (1), wherein in the housing part (1) for filling a high pressure element space (3) with fuel, a suction valve (4) is integrated, wherein the suction valve (4) has a support element (22 ) and a magnet assembly (26), wherein a dial (17) between the support member (22) and a shoulder (18) of the housing part (1) is arranged and in the housing part (1) serving as an inlet for the suction valve (4) Low pressure chamber (8) is formed, in which a sieve element (9) is accommodated, wherein the sieve element (9) has two partial regions (28, 29), wherein in a first subregion (28) a sieve cloth (15) is arranged and a second Partial region (29) between the first portion (28) and the shim (17) angeordnet.Der invention, the second portion (29) axially to the first portion (28) is arranged and has a foldable in the axial direction structure ur up.

Description

The invention relates to a high-pressure pump, in particular for a fuel injection system, in particular a common-rail injection system, having the features of the preamble of claim 1.

State of the art

A high-pressure pump, in particular for a fuel injection system, serves to convey fuel to high pressure. For this purpose, a high-pressure pump has at least one pump element with a high-pressure element space, in which the fuel is compressed and then fed via a high-pressure outlet to a high-pressure reservoir, the so-called rail. The filling of the high pressure element space is usually via a suction valve, which may be designed as a mechanical suction valve or as an electromagnetically actuated suction valve. If the latter is the case, a metering unit upstream of the suction valve can be dispensed with, since the quantity metering can take place via the suction valve itself.

The suction valve can also be attached to the high-pressure pump or integrated into it.

A high pressure pump with integrated suction valve is an example of the published patent application DE 10 2012 210 107 A1 out. The suction valve described herein comprises a cooperating with a valve seat valve member which is received in a liftable manner in a bore of a housing part of the high-pressure pump and guided over a guide sleeve. The valve seat can be formed by the housing part of the high-pressure pump, so that a separate valve plate, in which usually the valve seat is formed, is dispensable. With the omission of the valve plate and the inlet holes fall away, over which - with the suction valve open - the fuel flows in the direction of the valve seat. The inlet therefore takes place in the suction valve described in the disclosure via recesses in the guide sleeve.

In the incoming fuel particles are often included, which can lead to malfunction of the suction valve and other downstream valves, such as a likewise arranged in the housing part of the high pressure pump high pressure valve and / or provided on a high-pressure accumulator pressure control valve. Therefore, it is necessary to remove such particles before they get into the suction valve. Suction valves are known from the prior art, which comprise an annular sieve element surrounding the valve plate. Such a suction valve is an example of the published patent application DE 10 2008 042 617 A1 out. This assumes, however, that a valve plate is present.

If the intake valve is preceded by a metering unit, it can be equipped with a sieve element, so that a further sieve element on the intake valve can be dispensed with. However, if such a metering unit is not provided, since it is, for example, an electromagnetically actuated suction valve, the harmful particles must be removed in another way. Failure to take any action in this regard will not only cause the suction valve and other valves to malfunction, but will result in failure of the pump.

Furthermore, sieve elements, as in 1 described, known to be loosely inserted their mounting position and depending on the tolerance situation of the affected individual components leads to a more or less strong axial jamming of Siebelements. The axial clamping force is relatively low, since this only takes place on the outer radius of the sieve, wherein the sieve there has a low material thickness and a relatively large lever acts, which has a negative effect on the axial bias.

The present invention is therefore based on the object of specifying a high-pressure pump - in particular for a fuel injection system - with an integrated suction valve, in which the risk of pump failure due to particles contained in the fuel is significantly minimized.

To solve the problem, the high pressure pump is specified with the features of claim 1. Advantageous developments of the invention can be found in the dependent claims.

Disclosure of the invention

The preferably for a fuel injection system, in particular a common rail injection system, proposed high pressure pump comprises a housing part, wherein in the housing part for filling a high pressure element space with fuel, a suction valve is integrated, wherein the suction valve comprises a support member and a magnetic assembly, wherein a shim between the Support member and a shoulder of the housing part is arranged and in the housing part serving as an inlet for the suction valve low pressure space is formed, in which a sieve element is received. Furthermore, the screen element has two subregions, wherein a screen fabric is arranged in a first subregion and a second subregion is arranged between the first subregion and the adjustment disc.

According to the invention, the second partial region is arranged axially relative to the first partial region and has a structure that can be folded in the axial direction.

The arrangement of the sieve element in the low pressure space, i. in the inlet region of the suction valve, ensures in an advantageous manner that any particles contained in the fuel do not enter the region of the valve seat and lead to malfunction of the suction valve. This also reduces the risk of failure of the high-pressure pump. Since the suction valve is protected by the sieve element accommodated in the low-pressure chamber, it does not matter whether the suction valve is preceded by a metering unit equipped with a sieve. The suction valve may therefore be both a mechanical suction valve and an electromagnetically actuated suction valve.

The sieve element advantageously has two partial regions, wherein the two partial regions fulfill different functions. The first portion is used to hold the mesh and the second portion is in contact with the shim, thereby preventing twisting of the sieve. By this separation of functions is achieved in an advantageous manner that stresses are reduced to the mesh and thus an undesirable deformation of the fabric can be avoided or reduced, whereby the filter performance of Siebelements would decrease. The second subregion is advantageously arranged axially relative to the first subregion and, moreover, advantageously has a foldable structure in the axial direction. Due to the foldable structure, the effect of reducing the tension in the axial direction on the screen cloth is advantageously optimized. In addition, contact force differences due to manufacturing tolerances of the components, such as the screen height, the depth of the filter assembly space and the cylinder head can be avoided in an advantageous manner.

A cost saving can result from the fact that axial tolerances of the components can be increased without the functionality and the robustness of the screen are reduced.

In a preferred embodiment, the second portion is advantageously formed from a bellows. By the bellows axial tolerances between the components of the high pressure pump can be compensated and it is still possible to achieve a required filter bias of the Siebelements between the housing part and the shim.

By the execution of the second portion by a bellows also the tolerances of the screen element, or the first portion of the screen element can be designed to be larger, thereby making this cheaper.

The use of the bellows thus makes it possible to maintain a constant biasing force of the sieve element between the housing part and the shim, in particular independently of the manufacturing tolerances. In addition, it ensures a secure sealing of the contact points, whereby a non-desired bypass between described in the later part of the description annular spaces of the low pressure space can be avoided.

In a development, the sieve element is designed in the form of a ring around a central axis and the bellows is arranged directly or indirectly on the first subregion of the sieve element. The annular design of the sieve element advantageously enables uniform contact in the axial direction of the sieve element between the shim and the housing part.

In a development, the bellows of the sieve element between the shim and the first portion of the sieve is arranged and biases the sieve axially between the shim and the housing part. This ensures in an advantageous manner that the screen element is fixed in position in the axial direction. The risk of relative movements is thus minimized. Preferably, the force required for the axial prestressing force is transmitted through the dial to the screen element, which is axially supported on a shoulder of the housing part and holds down the screen element. The shim is preferably axially biased against the shoulder of the housing part, for example, by a screwed with the housing part union nut, which serves to attach the suction valve on the housing part. The axial bias of the screen element through the dial against the housing part of the high-pressure pump counteracts micro-movements of the screen element relative to the housing part, whereby the screen element is fixed in position over the dial and the housing part at least in the axial direction. In this way, the wear of the screen element is minimized in the contact area with the housing part. This means that over the duration no wear-related axial play between the sieve element and the housing part is to be feared, over which particles contained in the fuel could enter the suction valve. Consequently, the risk of a particle-induced pump failure is further minimized via the axial bias of the screen element.

In one embodiment, the bellows is formed of the same material as the first portion of the sieve, wherein the bellows in an advantageous development is integrally formed on the first portion of the screen element.

As a result, the sieve element can be manufactured in a simple way from plastic or an elastomer, for example in an injection molding process. The screen mesh can be inserted into the injection mold. In this way, the screen element is simple and inexpensive to produce.

In a preferred embodiment, the bellows is a separate component and arranged on the first portion of the screening element.

Advantageously, the separate bellows is pressed into the first portion in a receptacle whereby a stable connection between the components is made. Furthermore, the material of the bellows can be selected specifically for the respective use and can be embodied differently from the material of the first subregion of the sieving element.

In a further embodiment, the separate bellows is glued to the first portion of the screen element.

A further embodiment provides that the separate bellows is pressed with an additional adhesive bond in the first portion.

In a development, the low-pressure space is formed in cross-section at least partially V-shaped and arranged the strainer substantially coaxially to the low-pressure space, so that it divides the low-pressure space into two annular spaces. The V-shaped design has the advantage that the low-pressure space widens towards the suction valve. A low-pressure space radially inwardly delimiting central dome of the housing part is formed in this case at least partially frusto-conical. For the purposes of the present application, a dome is understood to be a material shaping projecting from the surrounding area, which may, for example, have a conical shape. For this purpose, the screen element is preferably received in the low-pressure space such that it at least partially surrounds the central dome of the housing part or at least partially engages the central dome of the housing part in the screen element. Through the dome, the screen element is prevented in particular from movements in the radial direction.

The low-pressure space and the central dome can be easily manufactured in this way in a material-removing process, for example by turning. Preferably, the central dome on the base has a cylindrical portion on which the sieve element bears radially. However, the screen element may also be biased against the cylindrical portion of the dome.

Furthermore, the sieve element is arranged substantially centrally in the low-pressure space, so that it subdivides the low-pressure space into two annular spaces. Due to the central arrangement, the height of the Siebelements can be maximized, since it is located where the low pressure chamber has its greatest depth. According to the height can be maximized in this way, the area of the mesh fabric. The larger the area of the mesh, the lower the risk that it will become clogged over time.

• 1 einen schematischen Längsschnitt einer Hochdruckpumpe nach Stand der Technik im Bereich eines Saugventils und
• 2 einen Ausschnitt eines Ausführungsbeispiels einer erfindungsgemäßen Hochdruckpumpe.

Preferred embodiments of the invention are explained below with reference to the accompanying drawings. These show:

• 1 a schematic longitudinal section of a high-pressure pump according to the prior art in the region of a suction valve and
• 2 a section of an embodiment of a high-pressure pump according to the invention.

The 1 shows only a section of a high pressure pump according to the prior art, in the range of an electromagnetically actuated suction valve 4 for filling a high-pressure element space 3 with fuel in a housing part 1 the high pressure pump is integrated. The high-pressure element space 3 is in a cylinder bore 2 of the housing part 1 formed, wherein the cylinder bore 2 for forming a valve seat 7 for a liftable valve lifter 6 of the suction valve 2 stepped is executed. With no-current suction valve 4 becomes the valve lifter 6 from the spring force of a closing spring 5 in the valve seat 7 drawn.

The valve seat 7 is an annulus 21 upstream, in the inlet bores 20 lead to the annulus 21 with one in the housing part 1 trained annular low pressure space 8th connect. The inflow of fuel into the high pressure element space 3 thus takes place via the low-pressure space 8th , the inlet bores 20 and the annulus 21 , To prevent particles from entering the suction valve with the incoming fuel 4 and the high pressure element space 3 is registered in the low-pressure room 8th an annular sieve element 9 added. The sieve element 9 is with an inner peripheral area 11 at a central dome 10 of the housing part 1 arranged radially and on a stop 12 below the dome 10 the housing part arranged axially.

The sieve element 9 divides the low-pressure space 8th in two annular spaces 8.1 . 8.2 over which a screen mesh 15 of the sieve element 9 can be flowed on. The mesh 9 is therefore radial flows through. This has a portafilter 13 made of plastic and a mesh screen 15 on. On the portafilter 13 closes a collar 19 on, which is slightly increased radially outward, so that it forms a kind of spring arm over which the sieve element 9 can be prestressed in the axial direction.

For sealing the low pressure space 8th to the outside is in the housing part 1 a carrier element 22 of the suction valve 4 used, in the outer circumference a sealing ring 23 is inserted, which is against a hollow cylindrical receptacle 24 of the housing part 1 is radially biased. Furthermore, the suction valve 4 a magnet assembly 26 on, on the support element 22 is arranged. The carrier element 22 lies on a dial 17 on, over which the sieve element 9 is held down. At the magnet assembly 26 is a union nut 27 supported, with the hollow cylindrical receptacle 24 of the housing part 1 is bolted and the shim 17 over the carrier element 22 to an annular heel 18 of the housing part 1 supported.

The in 1 described basic structure of the high-pressure pump corresponds to the structure of the embodiment of the invention described below.

2 shows a section of a high-pressure pump according to the invention. The sieve element 9 has two parts 28 . 29 on, wherein in a first subarea 28 the mesh 15 is arranged and a second subarea 29 between the first subarea 28 and the dial 17 is arranged. The first section 28 fulfills the function of the portafilter 13 and lies with its inner peripheral area 11 radially on a stop 34 the dome 10 of the housing part 1 at.

The at least partially hollow cylindrical filter holder 13 includes window-like recesses 14 in which the screen mesh 15 is included. The mesh 15 Accordingly, in the main flow direction, ie in the feed direction of the fuel, flows through from radially outside to radially inside. The the sieve fabric 15 receiving window-like recesses 14 are preferably arranged distributed uniformly over the circumference, so that the sieve element 9 is flowed evenly.

The window-like recesses 14 are preferably separated by axially extending webs, not shown. The webs cause a stiffening of the portafilter 13 ,

About the tightening torque of in 1 described union nut 27 is the sieve element 9 over the dial 17 in the axial direction against the housing part 1 prestressable, with the dial 17 against the paragraph 18 of the housing part 1 is attracted.

Furthermore, the sieve element 9 ring around a central axis 41 of the valve lifter 6 trained and the second part 29 is axial to the first section 28 arranged and has a foldable structure in the axial direction. This is the second subarea 29 preferably from a bellows 29 educated. The sieve element 9 is preferably made of a plastic.

The sieve element 9 is through the between the shim 17 and the first subarea 28 of the sieve element 9 arranged bellows 29 between the housing part 1 and the dial 17 axially biased.

When tightening the union nut 27 becomes the dial 17 against the shoulder 18 of the housing part 1 attracted, with the dial 17 before reaching the paragraph 18 in contact with the bellows 29 comes and deforms so that the screen element 9 axially between the shim 17 and the housing part 1 braced, so that a twisting of the sieve element relative to the housing part 1 is avoided. By this arrangement are axially on the portafilter 13 . 28 acting forces largely avoided, allowing a deformation of the mesh fabric 15 is prevented.

It can be the bellows 29 be formed in one embodiment of the same material as the first portion 28 of the sieve element 9 and also in one piece to the first section 28 of the sieve element 9 be arranged.

In a preferred embodiment, the bellows 29 formed as a separate component and to the first portion 28 of the sieve element 9 arranged. The bellows can be in a groove of the first portion 28 be pressed or glued to this.

The low pressure room 8th is formed in cross-section at least partially V-shaped and the screen element 9 essentially coaxial with the low pressure space 8th arranged so that it is the low pressure space 8th in the two annular spaces 8.1 . 8.2 divided.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102012210107 A1 [0004]
• DE 102008042617 A1 [0005]

Claims (8)

High-pressure pump for a fuel injection system, comprising a housing part (1), wherein in the housing part (1) for filling a high-pressure element space (3) with fuel, a suction valve (4) is integrated, wherein the suction valve (4), a support member (22) and a magnet assembly (26), wherein a dial (17) between the support element (22) and a shoulder (18) of the housing part (1) is arranged and in the housing part (1) serving as an inlet for the suction valve (4) low pressure chamber (8) in which a sieve element (9) is accommodated, the sieve element (9) having two subareas (28, 29), wherein a sieve cloth (15) is arranged in a first subarea (28) and a second subarea (29) is arranged between the first portion (28) and the shim (17), characterized in that the second portion (29) is arranged axially to the first portion (28) and has a foldable structure in the axial direction. High pressure pump after Claim 1 , characterized in that the second portion (29) is formed of a bellows (29). High-pressure pump according to one of the preceding claims, characterized in that the sieve element (9) is formed annularly around a central axis (41) and the bellows (29) is arranged directly or indirectly on the first portion (28) of the sieve element (9). High-pressure pump according to one of the preceding claims, characterized in that the sieve element (9) is arranged between the housing part (1) and the adjusting disk by means of the bellows (29) arranged between the adjusting disk (17) and the first subregion (28) of the sieve element (9) (17) is axially biased. High-pressure pump according to one of the preceding claims, characterized in that the bellows (29) is formed from the same material as the first portion (28) of the sieve element (9). High pressure pump after Claim 5 , characterized in that the bellows (29) is arranged integrally with the first portion (28) of the sieve element (9). High pressure pump according to one of the Claims 1 to 4 , characterized in that the bellows (29) is a separate component and arranged on the first portion (28) of the Siebelements (9), in particular pressed and / or glued. High-pressure pump according to one of the preceding claims, characterized in that the low-pressure space (8) is at least partially V-shaped in cross-section and the sieve element (9) is arranged substantially coaxially to the low-pressure space (8), so that it forms the low-pressure space (8). divided into two annular spaces (8.1, 8.2).

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