WO2010025981A1

WO2010025981A1 - High-pressure radial piston pump

Info

Publication number: WO2010025981A1
Application number: PCT/EP2009/058918
Authority: WO
Inventors: Friedrich Boecking; Sylvain Besancon; Matthias Greiner
Original assignee: Robert Bosch Gmbh
Priority date: 2008-09-02
Filing date: 2009-07-13
Publication date: 2010-03-11
Also published as: RU2011112307A; ES2379516T3; RU2500923C2; JP5135473B2; CN102144096B; EP2331821B1; KR20110047210A; ATE545785T1; DE102008041751A1; CN102144096A; EP2331821A1; JP2012501409A

Abstract

The invention relates to a high-pressure radial piston pump for the fuel supply of an internal combustion engine, comprising a housing (1) having a drive shaft (2) that is accommodated therein, rotates about an axis and has a cam or eccentric disk (3) projecting in the radial direction by means of which multiple pistons (5) accommodated in cylinders (4) are engaged, which can be successively displaced in the radial direction by the cam or eccentric disk (3), wherein the housing (1) is equipped with a mounting flange for mounting the same to the internal combustion engine, wherein the cylinders (4) are connected via fuel lines, which are proportionately accommodated in the housing (1). The mounting flange (6) and the housing (1) are formed by separate parts. A low-pressure unit (7) is attached to the side of the housing (1) facing away from the mounting flange (6), wherein the mounting flange (6) and the low-pressure unit (7) are connected to the housing such that they can rotate relative to each other and to the housing (1) and together with the housing (1) limit annular channels (8) which concentrically surround the drive shaft (2), and wherein the fuel lines comprise lines that are proportionately formed by means of the annular channels (8).

Description

Title: High pressure radial piston pump

description

Technical area

The invention is based on a high-pressure radial piston pump according to the preamble of claim 1.

State of the art

Such a high-pressure radial piston pump is known from DE 102 47 142 A1. It is intended for the fuel supply of an internal combustion engine and usually between a fuel supply and a high-pressure accumulator, also called common rail arranged, to which the individual injection nozzles of the internal combustion engine are connected. The mounting flange and the housing are bolted together in the known high-pressure radial piston pump, which makes it possible to produce the housing made of higher quality material than the mounting flange, on the one hand to obtain low manufacturing cost and on the other hand, to cope with the high pump pressures, in the Housing bores must be included. However, the mounting flange and the housing are in the known high-pressure radial piston pump connected to each other in a predetermined mutual assignment, which can not be changed without changing the hard-to-edit housing with the result that such high-pressure radial piston pumps in all details specifically to the respective Requirements of the customer's use must be adjusted. This applies to the positioning and size of the screw holes, which are used for mounting on a specific internal combustion engine, as well as the location and positioning of all customer fuel connections and the internal structure. Accordingly, it is necessary for each customer and each use to adapt the basic assembly formed by the mounting flange and the housing in total to the respective requirements, which in addition involves costly changes to the built-in components contained therein. The resulting manufacturing costs are therefore very high.

DISCLOSURE OF THE INVENTION The high-pressure radial piston pump according to the invention with the features according to claim 1 has the advantage that there is a reduction in the production of the high-pressure radial piston pump, combined with the advantage that the customer-side connections are arranged closely adjacent and separate adjustments often even are dispensable. It is very special Advantage that any necessary adjustments can be made on a wide scale without changing the difficult-to-process, high-strength housing and the built-in components by the low-pressure unit and / or the mounting flange twisted around its axis relative to the housing in the appropriate extent and be determined using the threaded holes already in the housing as standard.

In the dependent claims advantageous refinements and developments of the high-pressure radial piston pump according to the invention are given.

Due to the design according to claim 2, the advantage is obtained that the low-pressure unit can be manufactured using inexpensive materials and easily edited on machines and, if necessary, can be changed. The sealing of the annular channels according to claim 3 by O-ring seals, which are inserted in rectangular grooves, is particularly easy to produce. The O-ring seals need only be inserted into the prefabricated annular grooves of the low-pressure unit and / or the mounting flange and / or the housing on both sides of the respective annular channel and then pressed elastically with a smooth counter surface of the respective opposite part to the desired seal to achieve. The O-ring seals preferably consist of permanently elastic, elastomeric materials. They are also available in cases in which an annular channel is arranged in a corner region, such that the one O-ring seal is inserted in an axial direction open to the counter surface groove and the other in a radial direction open to the counter surface groove.

Due to the embodiment according to claim 4, a region is used as an annular channel, which is the drive shaft radially adjacent to each other particularly closely. This allows to reduce the radial dimensions of the high pressure radial piston pump to a minimum.

By the formation according to claim 5, it is possible to reduce the axial dimensions of the high-pressure radial piston pump to a minimum.

The embodiment according to claim 6 ring channels, which are arranged in the region of the opposite end faces or ends of the high-pressure radial piston pump, functionally coupled together, which allows the low-pressure connections in addition to the high-pressure connections of the high-pressure radial piston pump on the side remote from the internal combustion engine side the high-pressure radial piston pump and bundle on this page. Due to the construction according to claim 7, a particularly simple connection is obtained from an annular channel to all intake ports of the intake valves of each cylinder head and the pump chambers contained therein. To make the connection, it only requires the assembly of the cylinder heads. For the feeding of the fuel into the relevant annular channel, either a connection for an optionally pressurized fuel line is provided at the front of the low-pressure unit or for a metering unit which feeds the fuel into the annular channel depending on the respective requirement.

The embodiment according to claim 8 makes it possible to inexpensively connect the high-pressure connections free of intersections and merging into each other buffer sections. The embodiment according to claim 9 makes it possible to connect a metering unit and the low-pressure unit particularly simple. Functional elements of the metering unit, such as the zero delivery throttle, can be integrated into the low-pressure unit, which greatly simplifies the construction of the metering unit. If a prefeed pump is used to supply the low-pressure unit, it is recommended that the prefeed pump be flanged directly onto the low-pressure unit and that the high-pressure radial-piston pump drive shaft be used to drive it. In particular gear pumps can be easily integrated in this way.

drawing

Several embodiments of the invention are illustrated in the drawing.

They are explained in more detail below. 1 shows a high-pressure radial piston pump in a front view.

Fig. 2, the high-pressure radial piston pump of FIG. 1 in longitudinally sectioned

Presentation. The high-pressure channels contained in the housing are arranged in separate radial planes of the drive shaft.

Fig. 3 is a high-pressure radial piston pump similar to FIG. 1 in longitudinal section. The low-pressure unit is provided with annular channels, which are connected by a bore extending approximately parallel to the drive shaft.

Fig. 4 is a high-pressure radial piston pump in longitudinal section, which has two opposing piston / cylinder cleanliness and a drive shaft.

Fig. 5 is a high-pressure radial piston pump in longitudinal section, in which the housing has at the two end faces annular channels, which are connected by two holes 10 intersecting each other.

Fig. 6 to 9 different cylinder heads in a cross-sectional view, in which the high-pressure port is positioned differently.

Description of the embodiments:

Corresponding reference characters indicate corresponding objects throughout the drawings. Fig. 1 shows a high pressure radial piston pump for the fuel supply of an internal combustion engine in a front view. It comprises a housing 1 with a drive shaft 2 received therein and rotating about an axis with a cam or eccentric 3 protruding in the radial direction. With the cam or eccentric 3, three pistons 5 uniformly distributed in the circumferential direction and received in cylinders 4 are in direct and continuous Engaging, which are successively displaceable in the radial direction by the cam or eccentric 3 and a cooperating compression spring back and forth. The compression springs can also be omitted when using a positive guidance of the piston by the eccentric. During the reciprocating movement of the pistons, fuel is alternately drawn into the respective pump chamber 25 of the individual cylinders by a suction valve 24, compressed therein and collected under high pressure of more than 2,000 bar via the individual high-pressure valves 20 and the high-pressure bores 14, a central high-pressure connection 21 supplied and squeezed out via this into a high-pressure collector or a common rail, to which the individual injection nozzles of the associated internal combustion engine are connected. The housing 1 is provided for fixing to the internal combustion engine with a mounting flange 6 having screw holes for passing through fastening screws.

The three cylinders 4 are connected by fuel lines, which are proportionally included in the housing 1, the mounting flange 6 and the low-pressure unit 7 or limited thereby, wherein the mounting flange 6, the low-presure unit 7 and the housing 1 through formed independent parts and are relatively rotatable and liquid-tight fixed to each other.

The mounting flange 6 and the low-pressure unit 7 may consist of conventional, easy-to-process structural steel or aluminum and the housing 1 made of high-strength steel. The high-pressure lines 14, 13, which are proportionally contained in the housing 1 and in the cylinder heads 11, serve to collect the high-pressure volumes of the fuel generated by the individual sub-pumps and supply them to the central high-pressure port 21, to which the high-pressure accumulator (not shown) is connected. The high-pressure lines 14, 13 can be loaded with fuel at a pressure of more than 2,000 bar. Accordingly, they are limited exclusively by machine parts made of high-strength materials, namely the cylinder heads 11 and the housing 1. They connect the adjacent cylinder heads 11 without any intercommunication. As a result, notch effects are avoided, which can cause cracking under the operational, constantly increasing and decreasing high pressure stress.

1, the freedom of intersection of the high-pressure lines 13, 14 is achieved in that the mutually opposite orifices on the part of the cylinder heads 11 and the housing 1 are at a distance from each other. Furthermore, the immediately adjacent high-pressure lines 14 may be disposed within the housing 1 in different radial planes of the drive shaft 2, as shown in Fig. 2. The housing 1, the low-pressure unit 7 and a gear pump 17, which serves for the advancement of the fuel are bolted to each other in the construction of FIG. 1 perpendicular to the plane of the drawing. The mounting flange 6 is not visible in Fig. 1.

On the front side of a cylinder head 11, the central high-pressure port 21 is provided, via which the high-pressure fuel is transferred into the high-pressure accumulator, not shown.

FIG. 2 shows the position of the mounting flange 6 on the side of the housing 1 facing away from the low-pressure unit 7.

The mounting flange 6 and the low-pressure unit 7 are rotatable relative to each other and to the housing 1 connected to the housing 1 and they limit together with the housing 1 ring channels 8, which surround the drive shaft 2 concentrically, wherein the fuel lines comprise line sections, which are formed proportionally by the annular channels 8. If a connection of the mounting flange 6 or the low-pressure unit proves to be less favorable by the customer, therefore, the mounting flange 6 and / or the low-pressure unit can be rotated by a relative rotation with respect to the housing 1 in a more favorable position and bolted using the old threaded holes of the housing 1 with this. In this case, the annular channels 8 are still used and the threaded holes of the housing 1. The modification effort is accordingly low. It does not require the difficult machining of high-strength materials. The low-pressure unit 7 and / or the mounting flange 6 may be made of aluminum or steel. They limit only annular channels 8, the suction side connected to the suction valves of the high-pressure radial piston pump and accordingly only with a pressure of max. 6 bar are loaded. The determination of the high-pressure radial piston pump on an internal combustion engine does not require large forces, which cost and easily machinable materials for the production de mounting flange satisfy. The annular channels 8 are sealed in each case adjacent sealing gap in each case by O-ring seals 9, which are received elastically resilient in Rechecknuten a matched to their diameter profile. They ensure a good sealing result with the simplest installation. Preferably, the O-ring seals made of permanently elastic, polymeric material, in particular of synthetic rubber. The low-pressure unit 7 and the mounting flange 6 at the same time contain the bearings of the drive shaft 2. This not only high-strength and therefore expensive material is saved on the part of the housing 1, but created an additional way to bundle many ring channels 8 in a confined space and to use for forwarding fuel. In addition, the improve Possibilities to align the drive shaft 2 in the housing 1 exactly. The bearings of the drive shaft 2 can also be accommodated in the housing 1.

The low-pressure unit 7 is provided at the lower end with a Kraftstoffan end 22 which is connected to the fuel tank. The fuel inlet 22 may include a fuel filter.

With the front of the low-pressure unit 7, a gear pump 17 is screwed. It serves to feed the fuel to the high-pressure radial pump. 2 also shows that the drive shaft 2 of the high-pressure radial pump is extended through the low-pressure unit 7 and at the same time as the drive shaft 2 of the gear pump 17 is formed. The gear pump 17 therefore needs no separate drive and can be mounted together with the high-pressure radial piston pump and the low-pressure unit 7 in a single operation on an internal combustion engine and put into operation.

Fig. 3 shows two annular channels 8, which is bounded on three sides by the low-pressure unit 7 and on one side of the housing 1 and an annular channel 8 which is bounded on two sides by the mounting flange 6 and the housing 1. Of course, the assignment can also be reversed or made multiple times without departing from the spirit of the invention. The low-pressure unit 7 also engages over the edge of the housing 1 on one side with a radial projection, to which a metering unit, not shown, can be connected directly or through a line. The metering unit serves to adapt the volume of the fuel supplied to the high-pressure radial piston pump to the actual requirements in order to prevent the maximum delivery capacity of the high-pressure radial piston pump from being used even when the internal combustion engine supplied thereto is idling or in the partial load range and therefore a lot has less need. As a result of the interposition of the metering unit between the high-pressure radial piston pump and the fuel feed pump, which is formed here by a toothed edge pump 17, energy wastage is avoided. A proportionately of the mounting flange 6 and a proportionately limited by the low-pressure unit 7 annular channel 8 is connected in the design of FIG. 3 through a bore 19 which penetrates the housing 1 between the two end faces. The fuel delivered by the gear pump 17 is fed into the low-pressure unit 7, metered by the metering unit connected thereto and fed into the radially outer annular channel 8. He passes from there through the bore 19 in the proportionately limited by the mounting flange 6 annular channel 8 and from this into the radial bores 10, through which the suction valves 24 of the cylinder heads 11 of the high-pressure radial piston pump are fed. It is provided that the proportionately limited by the mounting flange 6 annular channel 8 is cut by as many radial holes 10 as overlapped by cylinder heads 11 of the cylinder 4, wherein the cylinder heads 11 include intake ports 12 and wherein the intake ports 12 and the radial bores 10 connected to each other are. All these lines are assigned to the suction side of the high-pressure radial piston pump and only with a pressure of max. 6 bar loaded. Therefore, no crack formation in the housing 1 is to be feared by the intersections between the annular channels 8 and the radial bores 10 used here. The intake openings 12 of the cylinder heads 11 contain check valves 24, which can only be flowed through in the direction of the pump chambers 25 of the cylinder 4. The suction openings 12 are closed to the outside by screw plugs 23.

The cylinder heads 11 in the design of FIG. 1 each have two high pressure ports 13, the high pressure ports 13 of adjacent cylinder heads 11 through holes 14 of the housing 1 with connected separate terminals. As a result, mutual intersections of holes are avoided within the housing 1, which significantly contributes to improve the durability under the conditions of continuous threshold load, which is exposed to such a housing during normal use.

4 shows a high-pressure radial piston pump in longitudinal section, which has only two opposing piston / cylinder units on both sides of the drive shaft 2. The pistons of the piston / cylinder units are pressed by compression springs 18 against a polygonal shoe 24, which is mounted so as to be relatively rotatable on the eccentric 3 of the rotating drive shaft 2. Otherwise, the structure and function of the above described. Fig. 5 is a high-pressure radial piston pump in longitudinal section, in which the housing 1 at the two end faces annular channels 8, which are connected by two holes 19 intersecting each other. The interior of the high-pressure radial piston pump is thereby bypassed. 6 to 9 show different cylinder heads 11 in a cross-sectional view, in which the high-pressure port 13.1 is positioned differently and the junction of the non-cutting holes 14 in the high-pressure valve 20 is indicated. Unnecessary outputs are closed by a screw plug 13.2.

The various designs can be used as desired by the customer with the aim of positioning the central high-pressure port 13.1 of the associated high-pressure radial piston pump in a space-saving manner in the often narrow engine compartment of a motor vehicle. In conjunction with the possibility to bundle all suction lines within the assembly of gear pump 17, low-pressure unit 7, housing 1 and mounting flange 6, wherein all Kraftstoffein- and outputs are close to each other on the same side of the high-pressure radial piston pump, it is possible to maintain a good overview in the engine compartment with optimal space utilization.

Claims

claims

1 . High-pressure radial piston pump for the fuel supply of an internal combustion engine, comprising a housing (1) having received therein and rotating about an axis drive shaft (2) with a radially projecting cam or eccentric (3), with the more in cylinders (4) recorded Pistons (5) are engaged, which are successively displaceable in the radial direction by the cam or eccentric (3), wherein the housing (1) for attachment to the internal combustion engine is provided with a mounting flange (6), wherein the cylinders (4) are connected by fuel lines (10) which are proportionately received in the housing (1) and wherein the mounting flange (6) and the housing (1) by independent

Parts are formed, characterized in that on the side facing away from the mounting flange (6) of the housing (1) a low-pressure unit (7) is fixed, that the mounting flange (6) and the low-pressure unit (7 ) are rotatably connected to the housing (1) relative to each other and to the housing (1) and together with the housing (1) define annular channels (8) concentrically surrounding the drive shaft (2) and the fuel lines (10) comprise conduit sections , which are proportionately formed by the annular channels (8).

2. High-pressure radial piston pump according to claim 1, characterized in that the low-pressure unit (7) consists of aluminum or steel.

3. High-pressure radial piston pump according to claim 1 or 2, characterized in that the annular channels (8) are sealed by O-ring seals (9).

4. High-pressure radial piston pump according to one of claims 1 to 3, characterized in that at least one annular channel (8) is provided, on three sides of the low-pressure unit (7) or the mounting flange (6) and on one side is bounded by the housing (1).

5. High-pressure radial piston pump according to one of claims 1 to 4, characterized in that at least one annular channel (8) is provided, on two sides of the low-pressure unit (7) or the mounting flange (6) and on two sides is bounded by the housing (1).

6. High-pressure radial piston pump according to claim 5, characterized in that at least one of the mounting flange (6) and a proportionately of the low-pressure unit (7) limited annular channel (8) through a bore (19) is connected to the Housing (1) penetrates between the opposite faces.

7. High-pressure radial piston pump according to claims 6, characterized in that an annular channel (8) by at least two radial bores (10) is cut, which are overlapped by the cylinder heads (1 1) of the cylinder (4) that the cylinder heads (1 1 ) Intake openings (12) and that the suction openings (12) and the radial bores (10) are connected in one another.

8. High-pressure radial piston pump according to claim 7, characterized in that the cylinder heads (1 1) each contain two high pressure openings (13) and that the high pressure openings (13) of adjacent cylinder heads (1 1) by

High-pressure bores (14) of the housing (1) are connected to separate terminals.

9. High-pressure radial piston pump according to one of claims 1 to 8, characterized in that the low-pressure unit (7) has a Includes connection (15) for a metering unit and that the terminal (15) is connected to an annular channel (8).

10. High-pressure radial piston pump according to one of claims 1 to 8, characterized in that the drive shaft (2) through the low pressure unit (7) extends through and as drive shaft (2) of a gear pump (17) is formed and that the Gear pump (17) on the low-pressure unit (7) is fixed.