WO2012049069A1

WO2012049069A1 - High pressure pump

Info

Publication number: WO2012049069A1
Application number: PCT/EP2011/067484
Authority: WO
Inventors: Thomas Schmidbauer
Original assignee: Continental Automotive Gmbh
Priority date: 2010-10-14
Filing date: 2011-10-06
Publication date: 2012-04-19
Also published as: DE102010042437B4; DE102010042437A1

Abstract

The invention relates to a high pressure pump (10) for delivering fuel, in particular diesel fuel, for a motor vehicle, comprising a first housing part (40) having a first mounting point (18), a second housing part (42) having a second mounting point (20), a shaft (14) for driving the high pressure pump, wherein the shaft (14) is mounted in the first mounting point (18) and the second mounting point (20), at least one eccentric (16), wherein the eccentric (16) is arranged on the shaft (14), and wherein the eccentric (16) is detachably connected to the shaft (14) and the first housing part and the second housing part are designed as one piece to form a pump housing (12). The eccentric can drive a piston (22) guided in a cylinder of the high pressure pump so as to deliver fuel. Because of the high pressure pump (10) according to the invention, it is possible to reduce the wear of the components of the high pressure pump (10).

Description

description

The invention relates to a high-pressure pump, for example a fuel pump, with the aid of which fuel for a ^motor vehicle can be conveyed.

Typically, high pressure pumps in motor vehicles as a fuel pump, in particular for diesel fuels used in ^¬ play, in common rail systems, wherein the fuel to a pressure of about 1000 to 2000 is compacted bar. The high pressure pump has a compressor unit with a cylinder for high pressure compression. The

Compressor unit has a driven by a shaft with an eccentric piston, which is guided in a cylinder bore of the cylinder.

The disadvantage of such a high-pressure pump is that due to the high pressure in the compression of the fuel, the components of the high-pressure pump subject to heavy wear un ^¬ .

It is the object of the invention to provide a high pressure pump, by means of which the wear of the components of the high-pressure pump can be reduced.

The object is achieved by the features of claim 1. Advantageous embodiments of the invention are specified in the dependent claims.

The high-pressure pump according to the invention for conveying fuel, in particular diesel fuel, for a motor vehicle, comprises a first housing part with a first bearing point, a second housing part with a second bearing point, a shaft for driving the high-pressure pump, wherein the shaft in the first bearing point and the second bearing point is mounted, at least one eccentric, wherein the eccentric is arranged on the shaft, and the eccentric is releasably connected to the shaft and the first housing part and the second housing part are integrally formed as a pump housing. By releasably connected to the shaft eccentric is made possible that the eccentric and the shaft are made separately. As a result, the shaft can be designed as a continuous rotationally symmetrical standard component, where ^{¬ be made possible} by cost savings due to the simpler geometry of the shaft in the production. The eccentric may be configured as an eccentrically designed socket. The eccentric can be releasably connected, for example, positively, or by means of an additional fastening element with the shaft. The mounting of the eccentric on the shaft can be done during assembly of the high-pressure pump, wherein after the introduction of the eccentric in the pump housing, the shaft can be inserted into the housing and connected to the eccentric. The use of a continuous rotationally symmetrical shaft allows the arrangement of the first bearing and the second bearing in the same one-piece pump housing, whereby an offset of the first bearing to the second bearing can be avoided. The first bearing and the second bearing can be arranged spaced from each other. As a result, a particularly good alignment of the first bearing point and the second bearing point can be achieved, so that a

Misalignment or tilting of the shaft can be avoided. Due to the improved alignment of the bearing points, a more uniform introduction of the shaft load into the bearing point can be achieved. Due to the more even introduction of the shaft load in the bearings, an edge load in the bearings can be avoided, which ensures that during operation of the high-pressure pump wear, in particular the shaft can be reduced in the field of bearings. In addition, expensive operations to produce the alignment of the bearings, for example, spindling the mounted bearings, avoided. In addition, the force flow through the bearing reaction forces within the one-piece pump housing, resulting in a more robust and deformation poorer High pressure pump is possible. In the high-pressure pump according to the invention, the low-pressure function of the high-pressure pump can be integrated into the pump housing, whereby the lid or the control disk used in conventional high-pressure pumps can be dispensed with, whereby the production of the high-pressure pump according to the invention can be simplified and costs can be reduced.

According to one embodiment, the high-pressure pump has a cylinder in which a piston is guided to convey the fuel and can be driven by the eccentric. In this case, the cylinder may have a cylinder housing with a cylinder bore, in which the piston is guided.

In a preferred embodiment of the invention, the pump housing has a first opening for the axial introduction of the shaft into the pump housing and at least one second opening for the radial introduction of the eccentric in the pump housing. Characterized in that the pump housing according to the invention has a first opening and at least one second opening for separate introduction of the shaft and the eccentric in the pump housing, the openings can be adapted to the dimensions of the components to be introduced. Through the separate openings, the geometry of the pump housing can be designed in such ^¬ that the bearings are arranged for rotatable mounting of the shaft in a one-piece pump housing. The first opening for axial insertion of the shaft into the pump housing may have a slightly larger diameter than the largest shaft diameter. The at least one second opening may be configured such that the eccentric can be introduced into the pump housing in the radial direction, essentially at right angles to the axis of rotation of the shaft. After inserting the eccentric in the pump housing, the shaft can be inserted through the first opening in the pump housing and connected to the eccentric. When using a

Multi-piston pump, the number of second openings can be increased and the configuration of the second opening can different drive types, such as an eccentric ring with sliding block, a circular drive or a cam with Roller joints, to be adjusted. In addition, the high-pressure pump according to the invention makes it possible, due to the first opening adapted to the shaft diameter, for smaller bearing point ^dimensions , since the shaft is introduced into the pump housing separately from the eccentric, as a result of which the installation space required for the high-pressure pump is reduced.

It is preferably provided that the first bearing point is arranged on one of the first opening facing side of the pump housing and the second bearing point is disposed on a side remote from the first opening side of the pump housing, wherein the diameter of the first bearing is greater than the diameter of the second bearing point , Due to the fact that the diameter of the first bearing point is greater than the diameter of the second bearing point, the shaft can have a smaller diameter at the points which are not supported at the first bearing point, for example a diameter adapted to the second bearing point the introduction side of the shaft more space for the introduction of the shaft into the pump housing, whereby damage to the first bearing can be avoided.

Furthermore, according to a preferred embodiment of the invention, the shaft has a first shaft section with a first shaft diameter for bearing in the first bearing point, a second shaft section with a second shaft diameter for bearing in the second bearing point, and a third shaft section with a third shaft Shaft diameter for receiving the eccentric, wherein the third shaft diameter is greater than or equal to the second shaft diameter and less than or equal to the first shaft diameter. The fact that the second shaft diameter can be smaller and the third shaft diameter smaller than or equal to the first shaft diameter, is in the introduction of the shaft in the pump housing through the first

Opening and through the first bearing point through more space for introducing the shaft into the housing. As a result, a gap around the shaft is formed which requires less effort Insertion of the shaft requires than with a shaft with a constant diameter. In addition, damage to the first bearing point during introduction of the shaft into the pump housing is avoided by the gap. Furthermore, the third shaft section may, for example, have a toothing formed in the axial direction for a positive connection of the shaft with a correspondingly configured eccentric. In this case, for example, the second shaft portion can be inserted with a smaller second shaft diameter than the third shaft portion through the third shaft portion, and a first shaft portion with an example, larger first shaft diameter than the third shaft diameter can form a shoulder, as a stop for the eccentric a prevents too much passage of the shaft through the eccentric.

Particularly preferably, it is provided that the second opening can be closed by a cylinder housing. By closing the second opening through the cylinder housing, the function of sealing the pump housing, in particular the second opening, can be combined with the function of accommodating the cylinder, whereby additional components can be avoided.

In a particularly preferred embodiment of the invention, the cylinder housing projects at least partially into the pump housing. Characterized in that the cylinder housing projects at least partially into the pump housing, a defined arrangement of the cylinder housing can be achieved relative to the pump housing. Moreover, the pump housing, particularly in the area of the second opening can be reinforced by the projecting into the pump housing cylinder housing, whereby the occurring forces can be better distributed on the Pum ^¬ pen housing due to the high pump pressures.

In a preferred embodiment of the invention, a cylinder bore is formed in the cylinder housing. The cylin ^¬ derbohrung can be formed in the region of the cylinder housing, which projects into the pump housing. By forming the cylinder bore in the cylinder housing can For example, a compact assembly are formed, which includes the high-pressure region of the high-pressure pump. In ^¬ play, the cylinder with the cylinder bore with the bearing in the cylinder bore piston and fuel connections may be arranged in the cylinder housing. By combining the high pressure area of the high pressure pump into a compact component, assembly costs can be reduced.

In a further preferred embodiment, the first bearing and the second bearing point is formed as a sliding bearing ^¬ out. Due to the fact that the first bearing point and the second bearing point are designed as slide bearings, in addition to a simplified assembly, a uniform load application from the shaft to the bearing points over the existing bearing point widths can be ensured. By the invention

Design of the high-pressure pump can be ensured an improved alignment of the first bearing and the second bearing, which due to the low-loss fluid friction while avoiding skewing the shaft operation with reduced wear can be ensured.

Particularly preferred exactly one shaft seal is provided for sealing the pump housing. Due to the inventive design of the high pressure pump having a first opening for introducing the shaft and a second opening which can be closed by the cylinder housing, the number of

Sealing points are reduced. For sealing the shaft, which is connectable to a drive and can protrude from the pump housing, in particular the first opening, exactly one shaft seal is provided, which in the form of a radial

Shaft seal or an axial shaft seal can be configured. The shaft seal may be arranged on the first opening, wherein the pump housing at the first opening may have a recess suitable for receiving the shaft seal, for example a seal seat. The shaft seal seals the low-pressure region of the high-pressure pump, for example, against escaping oil or dirt from the outside. The invention further relates to a motor vehicle with a high-pressure pump as described above and further developed. With the help of the high pressure pump according to the invention, the wear of the components of the high pressure pump can be reduced.

The invention with reference to the drawings ^¬ lying on the basis of preferred embodiments will be explained as an example.

It shows:

1 shows a schematic sectional ^{view of} a high-pressure pump according to the invention with a cylinder housing and a piston.

2 shows a schematic sectional ^{view of} a high-pressure pump according to the invention with a cylinder housing and two pistons.

3 shows a schematic sectional ^{view of} a high-pressure pump according to the invention with two cylinder housings and two pistons. It should first be noted that the same parts are provided with the same reference numerals in the figures.

In Fig. 1, a high pressure pump 10 according to the invention is Darge ^¬ represents. The high-pressure pump 10 comprises a one-piece pump housing 12 in which a shaft 14 is arranged, the shaft 14 being connected to an eccentric or eccentric section 16. More precisely, the pump housing 12 consists of a first housing part 40 and a second housing part 42. The eccentric 16 may be formed in one or more parts, for example, an inner eccentric element, which is connected to the shaft 14, and an outer eccentric element. The shaft 14 is at a first bearing 18 of the first

Housing part 40 and at a second bearing point 20 of the second Housing part 42 rotatably mounted. The first bearing 18 and the second bearing 20 are designed in the form of plain bearings. The high-pressure pump 10 further comprises a Zy ^¬ cylinder 21 with a cylinder housing 26, in which a cylinder bore 24 is provided. In the cylinder bore 24, a piston 22 is reciprocable (in the image plane up and down to move) out. The piston 22 is in contact with the eccentric 16 and is raised or lowered by the latter when the shaft 14 rotates with the eccentric 16. In this way, the drive of the piston takes place. By not shown

Fuel lines reaches fuel in an upper portion of the cylinder bore 24 and is compressed by the piston 22 during its upward movement and pressed under high pressure into a high-pressure line, also not shown, after the compression at least partially, for example to a

Common Rail system to be forwarded for fuel injection. The cylinder housing 26 projects at least partially into the pump housing 12. The pump housing 12 has, in addition to a first opening 28, a second opening 30. The second opening 30 is used in the assembly of the high-pressure pump 10 of the radial

Introduction of the eccentric 16 in the interior of the pump housing 12. The second opening 30 is closed by the cylinder housing 26 in the fully assembled high-pressure pump 10. The shaft 14 is inserted axially in the direction of its axis of rotation into the pump housing 12 and through the eccentric 16 after the eccentric 16 is already in. The first opening 28 is used during assembly of the high-pressure pump 10 of the introduction of the shaft 14 in the interior of the pump housing the pump housing 12 has been arranged. The shaft 14 projects partially out of the pump housing 12 and the first opening 28, and can be connected to a drive to drive the high-pressure pump to ^¬ . In the first opening 28, a seal seat is provided for receiving a shaft seal 32, which can prevent leakage of the oil of the sliding bearing 12 from the pump housing. The shaft 14 has at the first bearing 18 a first shaft portion 34, at the second bearing 20, a second shaft portion 36 and a third shaft portion 38 on the receptacle of the eccentric 16. The second Shaft diameter at the second shaft portion 36 corresponds to the third shaft diameter at the third shaft portion 38. The first shaft diameter of the shaft 14 at the first shaft portion 34 is larger than the second and the third shaft diameter. As a result, the shaft 14 forms a shoulder, which acts in the axial direction as a stop for the eccentric 16, whereby the shaft 14 and the eccentric 16 can be brought into a defined position to each other.

2 shows a high-pressure pump 10 according to the invention with a cylinder housing 26 and two pistons 22. In the pump housing 12, the shaft 14 is arranged, which is connected to an eccentric 16. The eccentric 16 is in the form of a double eccentric, which allows the movement of two pistons 22 simultaneously. The piston 22 to be moved are offset in the axial direction of the shaft 14, arranged side by side on the same side of the pump housing 12. Characterized in that the pistons 22 are arranged on the same side of the pump housing 12, the required cylinder bores 24 can both be arranged side by side in a cylinder housing 26. The cylinder housing 26 is arranged in the second opening 30 of the pump housing 12 and closes it. Due to the configuration of the eccentric 16, the pistons 22 do not compress the fuel in the cylinder bores 24 at the same time, but offset in time, whereby pressure peaks can be compensated and the delivery rate of the high-pressure pump can be increased.

A high pressure pump 10 according to the invention with two Zylinderge ^¬ housings 26 and two pistons 22 is shown in Fig. 3. The high-pressure pump 10 comprises a one-piece pump housing 12 in which the shaft 14 is arranged, wherein the shaft 14 is connected to the eccentric 16. The eccentric 16 is designed such that two in the axial direction of the shaft 14 lying at a height, but arranged on opposite sides of the pump housing 12 piston 22 can be moved by the eccentric 16. Die Exzenter 16 ist in der Ausnehmung 16 angeordnet. The opposing pistons 22 are each movably mounted in a cylinder bore 24 and thereby move in a common mode. For example, the pistons 22 compress at the same time the fuel in the cylinder bores 24. The two cylinder bores 24 are each arranged in a separate cylinder housing 26. For receiving the two Zy ^¬ relieving housing 26 has the pump housing 12 has two second openings 30, which are arranged according to the arrangement of the pistons on ge ^¬ opposite sides of the pump housing 12th The second openings 30 are each each closed by a cylinder housing 26, which partially project into the pump housing 12 pen ^¬ .

Claims

claims

A high-pressure pump for conveying fuel, in particular diesel fuel, for a motor vehicle, comprising a first housing part (40) with a first bearing (18), a second housing part (42) with a second bearing (20), a shaft (14) Drive of the high-pressure pump, wherein the shaft (14) in the first bearing (18) and the second bearing (20) is mounted, at least one eccentric (16), wherein the eccentric (16) on the shaft (14) is arranged, in that the eccentric (16) is detachably connected to the shaft (14) and the first housing part (40) and the second housing part (42) are integrally formed as a pump housing (12).

2. High-pressure pump according to claim 1, further characterized by a cylinder (21) in which a piston (22) for conveying the fuel out and driven by the eccentric (16).

3. High-pressure pump according to claim 2, characterized in that the cylinder (21) has a cylinder housing (26) with a

Cylinder bore (24), in which the piston (22) is guided.

4. High-pressure pump according to one of claims 1 to 3, characterized

in that the pump housing (12) has a first opening (28) for the axial introduction of the shaft (14) into the pump housing (12) and at least one second opening (30) for the radial introduction of the Exzenters (16) in the pump housing (12).

5. High-pressure pump according to claim 4, characterized in that the first bearing point (18) on one of the first opening (28) facing side of the pump housing (12) is arranged and the second bearing point (20) at one of the first opening (28). the opposite side of the pump housing (12) is arranged, wherein the diameter of the first bearing point (18) is greater than the diameter of the second bearing point (20).

6. High-pressure pump according to one of claims 1 to 5, characterized in that the shaft (14) has a first shaft portion (34) having a first shaft diameter for storage in the first bearing point (18),

a second shaft portion (36) having a second shaft diameter for mounting in the second bearing (20), and

a third shaft portion (38) having a third shaft diameter for receiving the eccentric (16),

wherein the third shaft diameter is greater than or equal to the second shaft diameter and

is less than or equal to the first shaft diameter.

7. High-pressure pump according to one of claims 3 to 6, characterized in that the second opening (30) through the Zy ^¬ lindergehäuse (26) is closable.

8. High-pressure pump according to claim 7, characterized in that the cylinder housing (26) projects at least partially into the pump housing (12).

9. High-pressure pump according to one of claims 1 to 8, characterized in that the first bearing point (18) and the second bearing point (20) are designed as sliding bearings.

10. High-pressure pump according to one of claims 1 to 9, characterized in that exactly one shaft seal (32) is provided for Ab ^¬ seal the pump housing (12).

11. A motor vehicle, comprising at least one high pressure pump (10) according to any one of claims 1 to 10.