DE102009002520A1 - High-pressure pump, particularly radial piston pump or in-line piston pump for fuel injection systems of air-compressing, self-ignited internal combustion engines, has pump assembly and drive shaft - Google Patents

Abstract

The high-pressure pump (1) has a pump assembly (8) and a drive shaft (3). The drive shaft has a cam (7) which is assigned to the pump assembly. The pump assembly has a roller (30) which runs on a cam running surface (32). The running surface of the cam is formed in concave or convex manner. A roller running surface (31) is adjustably formed at the concave or convex arrangement of the running surface of the cam.

Description

State of the art

The The invention relates to a high-pressure pump, in particular a radial or inline piston pump. Specifically, the invention relates to the field fuel pumps for fuel injection systems of air-compressing, self-igniting internal combustion engines.

From the DE 10 2005 046 670 A1 a high-pressure pump for a fuel injection device of an internal combustion engine is known. The known high-pressure pump has a pump housing, in which a pump element is arranged. The pump element comprises a driven by a drive shaft in a stroke pump piston. This pump piston is slidably guided in a cylinder bore of a part of the pump housing and limited in this one pump working space. The pump piston is supported on the drive shaft via a hollow-cylindrical ram, wherein the ram is displaceably guided in a bore of the pump housing in the direction of the longitudinal axis of the pump piston. Furthermore, the plunger has in its outer shell a groove extending in the direction of a longitudinal axis, in which engages radially to the longitudinal axis of the plunger in a part of the pump housing in a tangential direction to the plunger fixed ball for preventing rotation of the plunger.

The from the DE 10 2005 046 670 A1 known high-pressure pump has the disadvantage that the means for preventing rotation requires a certain design effort and requires a corresponding configuration of the pump housing for receiving the device for preventing rotation. In addition, it comes through the mediated via the ball permanent loading of the plunger to frictional losses, which deteriorate the efficiency.

Disclosure of the invention

The High-pressure pump according to the invention with the features of claim 1 has the advantage that a reliable Alignment of the pump assembly with a reduced constructive Effort is possible. Especially can friction losses prevented or at least reduced, reducing the efficiency the high-pressure pump improves and reduces wear are.

By the measures listed in the dependent claims are advantageous developments of specified in claim 1 High pressure pump possible.

Advantageous it is that the tread of the cam is concave is and that the roller surface of the roller in a middle Part of the role is convex or that the tread of the cam is convex and that the roller surface the role concave at least in a central part of the role is. Here, it is also advantageous that a radius of curvature the running surface of the cam and a radius of curvature the roller surface of the roller in the middle part in terms of amount at least are approximately the same size. This can on the one hand ensures a relatively large contact surface be relatively uniform to the actuation forces to distribute and thus prevent a point load. Furthermore a starting position can be specified, in which the roller, in particular at axial deflections, is returned.

Advantageous It is also that a diameter of the roll in a middle of the roll and a diameter of the roll in an exterior of the Roll vary from about 1% to about 10%. This allows at a deflection of the role from its initial position restoring forces, In particular, axial forces acting on the roller generates be to a reliable provision of the To ensure role in their starting position during operation.

Further it is advantageous that the roller surface of the roller in a first edge region opposite the tread the cam is configured reset and / or that the roller surface of the roller in a second edge region reset to the tread of the cam is designed. This can cause a certain edge drop or the like be given to the role, so that Hertzian voltage spikes are reduced or prevented in the peripheral areas.

It is also advantageous that the pump assembly has a roller shoe, that the roller shoe has a bearing surface on which the roller is mounted on the roller shoe, and that the bearing surface of the roller shoe is adapted to the configuration of the roller. This allows an advantageous guidance of the roller in the roller shoe. In particular, a mutual alignment can take place, so that the roller, the roller shoe and other elements of the pump assembly are aligned within operating within certain limits. This may allow a certain amount of play, which may be required for reliable operation. Due to the matched design of the roller shoe, the roller and the cam, a return to the desired starting position can be achieved by restoring forces in such deflections, which occur due to the deflection. A friction wear or the like is prevented or atin least prevented. It is particularly advantageous that the bearing surface of the roller shoe is configured concave or convex.

Advantageous it is that a radius of curvature of the tread of the cam and a radius of curvature of the bearing surface of the roller shoe are at least approximately the same size. This allows between the bearing surface of the roller shoe and the role of a relatively large contact area be predetermined, which prevents point loads or at least are reduced.

Furthermore It is advantageous that the tread of the cam and the roller surface of the roller are designed so that a centered initial position of the roll with respect to the tread of the cam is predetermined. This can be a certain distance of the role to other components of the pump assembly, in particular a plunger body, be guaranteed. An axial tarnishing to a boundary or a pumping load between the roller and the cam or roller and the roller shoe, which can occur at strong deflections, can be prevented.

Further It is advantageous that the tread of the cam and the roller surface of the roller are designed so that with an increasing axial deflection of the roller from the centered Starting position a steadily increasing restoring force on the role in the direction of the starting position. Especially At minor deflections of the roller can be a jump Increasing the restoring force prevented a required for the operation of the high-pressure pump game to ensure the role. Occurring here Frictional forces can thus be reduced so that prevents excessive wear is.

Brief description of the drawings

preferred Embodiments of the invention are in the following Description with reference to the accompanying drawings, in which corresponding elements with matching reference numerals are provided, explained in more detail. It shows:

1 a high pressure pump in a schematic, axial sectional view according to an embodiment of the invention;

2 the in 1 With II designated section of a high pressure pump according to another embodiment of the invention and

3 a diagram illustrating a Hertzian pressure on the roller in operation, to further explain the high-pressure pump of the embodiment of the invention.

1 shows a high pressure pump 1 in a schematic, axial sectional view according to an embodiment. The high pressure pump 1 can be configured in particular as a radial or inline piston pump. Specifically, the high pressure pump is suitable 1 as a fuel pump for fuel injection systems of air-compressing, self-igniting internal combustion engines. A preferred use of the high-pressure pump 1 consists of a fuel injection system with a fuel rail that stores diesel fuel under high pressure. The high-pressure pump according to the invention 1 However, it is also suitable for other applications.

The high pressure pump 1 has a multi-part pump housing 2 on, in which a drive shaft 3 is arranged. The drive shaft 3 is at two in the direction of a rotation axis 4 the drive shaft 3 spaced bearings 5 . 6 stored. The drive shaft 3 can be driven in rotation by an internal combustion engine.

The drive shaft 3 has at least one cam 7 on that between the campsites 5 . 6 on the drive shaft 3 is provided. In this case, the cam 7 be designed as a single or multiple cam. In addition, the term of the cam also includes a cam 7 passing through an eccentric section of the drive shaft 3 or the like is formed.

In the pump housing 2 is a pump assembly 8th arranged the cam 7 the drive shaft 3 assigned. The pump assembly 8th is at least essentially in a hole 9 of the pump housing 2 arranged. A cylinder head 10 the high pressure pump 1 is with the pump housing 2 connected to one of the pump assembly 8th assigned approach 11 of the cylinder head 10 into the hole 9 protrudes.

The pump assembly 8th has an at least substantially hollow cylindrical plunger body 12 up in the hole 9 is guided. In the ram body 12 is a driving element 13 used, which is designed disc-shaped and attached to a paragraph 14 of the plunger body 12 is applied.

The pump assembly 8th also has a piston 15 on, with the entrainment element 13 a covenant 16 of the piston 15 on a roller shoe 17 holds. That in the ram body 12 inserted entrainment element 13 is from a pestle spring 18 applied. The pestle spring 18 thereby holds the covenant 16 of the piston 15 in contact with the roller shoe 17 ,

The approach 11 has a cylinder bore 25 on, in which the piston 15 is guided. This limits the piston 15 a pump workroom 26 in the cylinder head 10 , The pump workroom 26 is via an inlet valve 27 filled with fuel. There is also an exhaust valve 28 provided via the high pressure fuel from the pump working space 26 to a fuel rail or the like can be conveyed.

The roller shoe 17 has a storage area 29 on, on the roll 30 the pump assembly 8th in the roller shoe 17 is stored. The role 30 has a roller surface 31 on, with the role 30 at the storage area 29 of the roller shoe 17 is slidably mounted. In addition, the cam has 7 a tread 32 on, at the roll 30 during operation of the high pressure pump 1 rolls. Here, the drive shaft rotates 3 around its axis of rotation 4 , A hub of the cam 7 transfers over the role 30 on the roller shoe 17 and thus the piston 15 , Furthermore, the pusher spring holds 18 the role 30 permanently in contact with the cam 7 , As a result, during operation alternately to a suction stroke, in which the piston 15 in one direction 33 moved, and to a delivery stroke, where the piston 15 against the direction 33 emotional. This can be done in the pump workspace 26 a high pressure is generated to deliver high pressure fuel via the exhaust valve 28 to promote.

During operation of the high pressure pump 1 rotates the drive shaft 3 around its axis of rotation 4 , so according to the role 30 around an axis 34 the role 30 rotates. In an initial position is the axis 34 the role 30 parallel to the axis of rotation 4 the drive shaft 3 oriented. In operation of the high pressure pump 1 However, there may be a certain amount of play in aligning the axle 34 the role 30 to be required. Furthermore, some axial movement of the roller 30 in or against an axial direction 35 to be required. However, excessive pivoting of the role 30 and excessive shifts in the role 30 in or against the axial direction 35 undesirable. Specifically, this can lead to excessive wear between the roller 30 and the storage area 29 of the roller shoe 17 or the tread 32 of the cam 7 come. Furthermore, it is conceivable that an axial displaceability of the roller 30 by a suitably designed plunger body 12 is limited. In this case, however, friction-related wear occurs between the roller in the respective stop positions 30 and a plunger body configured in this way 12 on what is undesirable.

The high pressure pump 1 of the embodiment therefore has an advantageous guidance of the role 30 on. This leadership is on the one hand the role 30 concerning the cam 7 aligned and centered centered. On the other hand, this also an orientation of the roller shoe 17 and optionally the plunger body 12 allows.

In the case of the 1 described embodiment is the tread 32 of the cam 7 concave. The roll surface 31 the role 30 is due to the concave configuration of the tread 32 of the cam 7 adapted designed. The role 30 has a middle part 36 on. In the middle part 36 the role 30 is the roll surface 31 Convex designed. The convex configuration of the roller surface 31 This is the concave design of the tread 32 of the cam 7 customized. A radius of curvature R _{N of} the tread 32 of the cam 7 and a curvature radius R _{R of} the roller surface 31 the role 30 amount are at least approximately the same size. This results in a uniform investment of the role 30 on the tread 32 of the cam 7 where one between the roller surface 31 the role 30 and the tread 32 of the cam 7 is prevented.

Furthermore, a radius of curvature R _{L of} the bearing surface 29 of the roller shoe 17 and the radius of curvature R _{R of} the roller surface 31 the role 30 in the middle part 36 amount at least approximately the same size. Thus, also between the roller surface 31 the role 30 and the storage area 29 of the roller shoe 17 allows a uniform investment, with a point load is prevented. Thus, it also follows that the radius of curvature R _{N of} the tread 32 of the cam 7 and the radius of curvature R _{L of} the bearing surface 29 of the roller shoe 17 at least approximately the same size.

A diameter D _{M of} the roll 30 in a middle 37 the role 30 and a diameter D _{A of} the roll 30 in a first outdoor area 38 and a second outdoor area 39 the role 30 vary from about 1% to about 10% of each other. This results in one in the axial direction 35 or against the axial direction 35 axial displacement of the roller 30 a restoring force on the roll 30 opposite or in the axial direction 35 that with increasing adjustment from in the 1 increases starting position increases. Thus, in an axial adjustment of the role 30 a provision in the in the 1 achieved starting position reached. Accordingly, the role 30 at possibly occurring pivoting of the role 30 returned to their original position, in which the axis 34 the role 30 parallel to the axis of rotation 4 the drive shaft 3 is oriented. In this case, there is the advantage that the restoring forces occurring with small deflections or pivoting are relatively low and increase evenly with the deflection or pivoting. This will be one for the operation of the high pressure pump 1 required game of role 30 allows. The emergence of undesirable frictional forces in the storage of the roll 30 on the tread 32 of the cam 7 as well as the storage area 29 of the roller shoe 17 is prevented. Outside of this required game occurring adjustments of the role 30 however, are corrected by correspondingly large restoring forces. This is a high reliability of the high pressure pump 1 guaranteed.

The role 30 has a first border area 41 and a second border area 42 on. The border areas 41 . 42 close to the middle part on both sides 36 the role 30 at. In the border areas 41 . 42 is the roll surface 31 the role 30 opposite the tread 32 of the cam 7 reset configured. This is the roller surface 31 the role 30 in the border areas 41 . 42 also opposite the storage area 29 of the roller shoe 17 designed back. Due to the recessed configuration are Hertzian voltage peaks in the edge areas 41 . 42 the role 30 reduced, as it is based on the 3 is illustrated.

In the in the 1 illustrated embodiment, the tread 32 of the cam 7 and the storage area 29 of the roller shoe 17 each concave, while the roller surface 31 the role 30 convex is configured. Another possible embodiment is based on 2 described in further detail below.

2 shows the in 1 With II designated section of the high-pressure pump 1 according to a further embodiment. In this embodiment, the tread 32 of the cam 7 and the storage area 29 of the roller shoe 17 each convex. Further, the roller surface 31 the role 30 concave. Both the tread 32 of the cam 7 as well as the storage area 29 of the roller shoe 17 are at the roller surface 31 the role 30 adapted designed. Here, the radius of curvature R _{N of} the tread 32 of the cam 7 and the radius of curvature R _{R of} the roller surface 31 the role 30 in the middle part 36 in terms of amount, approximately the same size. Further, the radius of curvature R _{L of} the bearing surface 29 of the roller shoe 17 and the radius of curvature R _{R of} the roller surface 31 the role 30 in the middle part 36 equal in size. In this case, the diameter D _{M of} the roll 30 in the middle 37 the role 30 and the diameter D _{A of} the roll 30 from about 1% to about 10% of each other. While in the case of the 1 described embodiment of the diameter D _M in the middle 37 the role 30 larger than the diameter D _A in the outer areas 38 . 39 , is based on the 2 illustrated embodiment, the diameter D _M in the middle 37 the role 30 smaller than the diameter D _{A of} the roll 30 in the outdoor areas 38 . 39 , However, also in the in the 2 illustrated embodiment of the role 30 a restoring force on the roll 30 generated when the role 30 in or against the axial direction 35 is adjusted from its initial position. This restoring force also increases evenly with increasing adjustment from the starting position. A certain game of the role 30 can be made possible in an advantageous manner.

The radius shape of the bearing surface 29 of the roller shoe 17 , the tread 32 of the cam 7 and the roller surface 31 the role 30 has the advantage that any tolerances occurring, in particular errors in the alignment of the pump assembly 8th perpendicular to the axis of rotation 4 the drive shaft 3 to be compensated.

The roll surface 31 the role 30 is in the border areas 41 . 42 reset configured.

3 shows a diagram that the Hertzian pressure P _H on the roller surface 31 the role 30 illustrated. Here, the ordinate is the Hertzian pressure P _H along the axis 34 in the axial direction 35 illustrated. The role 30 For example, according to the in the 1 be configured illustrated first embodiment. In the area of the middle 37 arises on the roller surface 31 a local maximum of the Hertzian pressure P _H. Starting from this local maximum 50 takes the Hertzian pressure to the edge areas 41 . 42 first off, until local minima 51 . 52 are reached. Then the Hertzian pressure increases from the local minimum 51 towards the first edge area 41 at. Due to in the first border area 41 recessed roller surface 31 the Hertzian pressure takes a local maximum 53 during Hertzian pressure P _H without the recessed first edge region 41 would continue to increase, as indicated by the broken line 54 is illustrated. Accordingly, the Hertzian pressure P _H decreases in the region of the second recessed edge region 42 a local maximum 55 which is smaller than the curve of the Hertzian pressure P _H without such a recessed edge region 42 as indicated by the broken line 56 is illustrated.

Thus, by the configuration of the roller surface 31 in the border areas 41 . 42 a limitation of the Hertzian pressure P _H can be achieved. In this case, the design of the roller surface takes place 31 preferably such that the local maxima 53 . 50 . 55 are at least approximately equal values for the Hertzian pressure P _H and a voltage difference to the local minima 51 . 52 is relatively small. This allows a uniform load on the roll 31 on the roller surface 31 , the storage area 29 of the roller shoe 17 and the tread 32 of the cam 7 be achieved.

The Invention is not limited to the described embodiments limited.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102005046670 A1 [0002, 0003]

Claims (10)

High pressure pump ( 1 ), in particular radial or inline piston pump for fuel injection systems of air-compressing, self-igniting internal combustion engines, with at least one pump assembly ( 8th ) and a drive shaft ( 3 ), which at least one of the pump assembly ( 8th ) associated cam ( 7 ), wherein the pump assembly ( 8th ) one on a tread ( 32 ) of the cam ( 7 ) running role ( 30 ), characterized in that the tread ( 32 ) of the cam ( 7 ) is concave or convex and that a roller surface ( 31 ) of the role ( 30 ) to the concave or convex configuration of the tread ( 32 ) of the cam ( 7 ) adapted adapted. High-pressure pump according to claim 1, characterized in that the running surface ( 32 ) of the cam ( 7 ) is concave and that the roller surface ( 31 ) of the role ( 30 ) at least in a central part ( 36 ) of the role ( 30 ) is convex or that the tread ( 32 ) of the cam ( 7 ) is convex and that the roller surface ( 31 ) of the role ( 30 ) at least in a central part ( 36 ) of the role ( 30 ) is concave. High-pressure pump according to claim 2, characterized in that a radius of curvature of the tread ( 32 ) of the cam ( 7 ) and a radius of curvature of the roller surface ( 31 ) of the role ( 30 ) in the middle part ( 36 ) amount at least approximately the same size. High-pressure pump according to one of claims 1 to 3, characterized in that a diameter of the roller ( 30 ) in a middle ( 37 ) of the role ( 30 ) and a diameter of the roll ( 30 ) in an outdoor area ( 38 . 39 ) of the role ( 30 ) differ by about 1% to about 10%. High-pressure pump according to one of claims 1 to 4, characterized in that the roller surface ( 31 ) of the role ( 30 ) in a first border area ( 41 ) opposite the tread ( 32 ) of the cam ( 7 ) is set back and / or that the roller surface ( 31 ) of the role ( 30 ) in a second border area ( 42 ) opposite the tread ( 32 ) of the cam ( 7 ) is set back. High-pressure pump according to one of claims 1 to 5, characterized in that the pump assembly ( 8th ) a roller shoe ( 17 ), that the roller shoe ( 17 ) a storage area ( 29 ), on which the roll ( 30 ) on the roller shoe ( 17 ) and that the storage area ( 29 ) of the roller shoe ( 17 ) to the design of the role ( 30 ) adapted adapted. High pressure pump according to claim 6, characterized in that the bearing surface ( 29 ) of the roller shoe ( 17 ) is configured concave or convex. High-pressure pump according to claim 7, characterized in that a radius of curvature of the tread ( 32 ) of the cam ( 7 ) and a radius of curvature of the bearing surface ( 29 ) of the roller shoe ( 17 ) are at least approximately the same size. High-pressure pump according to one of claims 1 to 8, characterized in that the running surface ( 32 ) of the cam ( 7 ) and the roll surface ( 31 ) of the role ( 30 ) are designed so that a centered starting position of the roll ( 30 ) with regard to the tread ( 32 ) of the cam ( 7 ) is given. High-pressure pump according to claim 9, characterized in that the running surface ( 32 ) of the cam ( 7 ) and the roll surface ( 31 ) of the role ( 30 ) are configured so that with an increasing axial deflection of the roller ( 30 ) from the centered starting position a uniformly increasing restoring force on the roll ( 30 ) acts in the direction of the starting position.