EP2652309B1 - High pressure pump - Google Patents

Description

State of the art

The invention relates to a high-pressure pump, in particular a radial or linear piston pump. Specifically, the invention relates to the field of fuel pumps for fuel injection systems of air-compression, 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 comprises a pump housing, in which a pump element is arranged, which comprises a driven by a drive shaft in a stroke pump piston. The 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 a part of the pump housing in the direction of the longitudinal axis of the pump piston. In the ram in the drive shaft end region facing a support element is used, in which a roller is rotatably mounted, which rolls on the cam of the drive shaft. The axis of rotation of the roller is at least approximately parallel to the axis of rotation of the drive shaft.

The from the DE 10 2005 046 670 A1 known high-pressure pump has the disadvantage that occur by the axial bearing of the roller in the ram friction forces and thereby wear. Among other things, forces which force the roller into an axial contact surface of the plunger, which results in the frictional forces and the wear between the roller and the plunger in the respective contact and contact areas, are caused by the dynamics of the pump drive. This can also cause particles by abrasion, which can lead to further pump damage.

From the DE 10 2006 031 032 A1 a pump tappet with a plunger housing is known, which has a longitudinally movably mounted in a guide tappet shirt and a roller space, and with a roll arranged in the roller space whose outer surface
can be driven by a pump cam and whose inner circumferential surface together with a bolt attached to the plunger housing forms a bearing point in the form of a sliding or needle bearing. To supply lubricant to the outer circumferential surface of the roller and / or to the bearing running transverse bores are provided by the plunger shirt, via which the roller space is connected to a lubricant feed channel opening into the guide. In this case, the tappet shirt should have an outer annular groove connecting the transverse bores with the lubricant supply channel.

Disclosure of the invention

The high pressure pump according to the invention with the features of claim 1 has the advantage that a performance of the pump assembly is improved. Specifically, the bearing of the roller can be improved, so that a friction-related wear is avoided or at least reduced. In addition, possibly occurring cavitation damage can be avoided.

The measures listed in the dependent claims advantageous refinements of the claim 1 high-pressure pump are possible.

It is advantageous that on the side surface of the roller at least one designed as a recess lubricant recess is provided. In operation, the side surface of the roller cooperates with the abutment surface of the tappet body to permit axial bearing. Lubricants, in particular diesel fuel, can be conducted to the contact area via the depressions in order to reduce the friction occurring. Thus, the hydrodynamic lubrication is improved. Here, it is also advantageous that the depression on the side surface of the roller to a rolling surface of the roller out is designed with a course that lies between a radial direction and a rotational direction of the roller. Specifically, the recess can be introduced at a certain angle in the side surface of the roller. In this way, as it were, a conveying effect for conveying the lubricant through the lubricant recess to the contact region can be achieved. As a result, the lubrication is further improved.

It is also advantageous that at least one lubricant recess designed as a blind hole is provided on the side surface of the roller. During the rotation of the roller, lubricant, in particular diesel fuel, can be taken up by the blind bore and then released again. Thereby, the lubrication in the contact area between the roller and the plunger body can be improved. It is advantageous that an axis of the blind hole is outwardly oriented at least partially in the direction of rotation of the roller. This results in a certain back pressure of the lubricant in the blind hole, whereby the hydrodynamic lubrication is improved.

However, it is also advantageous that the blind hole is at least approximately parallel to a rotational axis of the roller configured. In this way, the production of the roller can be facilitated with one or more blind holes. In addition, the blind hole can be made comparatively long.

It is also advantageous that on the side surface of the roller four or more designed as blind holes Schmierstoffausnehmungen are provided which evenly distributed about a rotation axis to the side surface of the roller and that the side surface is axially mounted at least in the region of the axis of rotation at the contact surface of the plunger body , In this way, it is achieved that during operation in the case of four blind bores one or two of the blind holes are unscrewed from the area of the contact surface and thus filled with the lubricant, while the other blind holes deliver lubricant between the side surface of the roller and the thrust surface of the plunger body , As a result, the region of the axis of rotation at the contact surface of the tappet body, on which at least substantially the friction with the roller can occur, can be advantageously lubricated.

It is also advantageous that at least one lubricant recess designed as a lubricant channel is provided on the plunger body and that one end of the lubricant channel opens onto the contact surface of the plunger body. Furthermore, it is advantageous that the lubricant channel is configured inclined from the inner abutment surface of the plunger body to an outer side of the plunger body in a conveying direction of the pump assembly. As a result, especially during the delivery stroke, lubricant, in particular diesel fuel, is guided to the contact region between the roller and the tappet body for axial bearing. Since during the delivery stroke, the forces occurring are particularly high and thus also by the dynamics of the pump drive forces that push the roller into the axial contact surface of the plunger body, are high, just then the hydrodynamic lubrication between the components significantly improved. It is also advantageous here that at least three Schmierstoffausnehmungen designed as a lubricant channel are provided on the plunger body and that the ends of the lubricant channels distributed around the axis of rotation of the roller to the contact surface of the plunger body. Thus, it is possible to lubricate the area which is particularly stressed by the friction.

Brief description of the drawings

• Fig. 1 eine Hochdruckpumpe in einer schematischen, axialen Schnittdarstellung entsprechend einem ersten Ausführungsbeispiel der Erfindung;
• Fig. 2 eine Laufrolle einer Pumpenbaugruppe der in Fig. 1 dargestellten Hochdruckpumpe aus der mit II bezeichneten Blickrichtung entsprechend einem zweiten Ausführungsbeispiel der Erfindung;
• Fig. 3 die in Fig. 2 dargestellte Laufrolle einer Pumpenbaugruppe der Hochdruckpumpe entsprechend einem dritten Ausführungsbeispiel der Erfindung;
• Fig. 4 einen Stößelkörper und eine Laufrolle einer Pumpenbaugruppe einer Hochdruckpumpe aus der in Fig. 1 mit II bezeichneten Blickrichtung entsprechend einem vierten Ausführungsbeispiel der Erfindung und
• Fig. 5 den in Fig. 1 mit V bezeichneten Ausschnitt einer Hochdruckpumpe in einer auszugsweisen, schematischen Schnittdarstellung entsprechend einem fünften Ausführungsbeispiel der Erfindung.

Preferred embodiments of the invention are explained in more detail in the following description with reference to the accompanying drawings, in which corresponding elements are provided with corresponding reference numerals. It shows:

• Fig. 1 a high pressure pump in a schematic, axial sectional view according to a first embodiment of the invention;
• Fig. 2 a roller of a pump assembly of in Fig. 1 illustrated high-pressure pump from the designated II viewing direction according to a second embodiment of the invention;
• Fig. 3 in the Fig. 2 illustrated roller of a pump assembly of the high pressure pump according to a third embodiment of the invention;
• Fig. 4 a plunger body and a roller of a pump assembly of a high-pressure pump from the in Fig. 1 Denoted by II viewing direction according to a fourth embodiment of the invention and
• Fig. 5 the in Fig. 1 with V designated section of a high-pressure pump in a partial, schematic sectional view according to a fifth embodiment of the invention.

Embodiments of the invention

Fig. 1 shows a high pressure pump 1 in a schematic, axial sectional view according to a first embodiment of the invention. The high pressure pump 1 can be configured in particular as a radial or inline piston pump. Specifically, the high-pressure pump 1 is suitable 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 is for a fuel injection system having a fuel rail which stores diesel fuel under high pressure. However, the high-pressure pump 1 according to the invention is also suitable for other applications.

The high-pressure pump 1 has a multipart pump housing 2 and a drive shaft 3 arranged in the pump housing 2. The pump housing 2 consists in this embodiment of a base body 4, a connected to the base 4 flange 5 and a cylinder head 6. The drive shaft 3 is mounted on a bearing 7 on the one hand to the flange 5 and on a bearing 8 on the other hand to the main body 4. In operation, the drive shaft 3 rotates about an axis. 9

The drive shaft 3 has at least one cam 10. On the cam 10, a tread 11 is formed. The term of the cam 10 is to be understood in this case in general. The cam 10 may for example also be configured as a multiple cam. Further The cam 10 may also be formed by an eccentric portion of the drive shaft 3.

The high-pressure pump 1 has a pump assembly 15. The pump assembly 15 is associated with the cam 10. In this case, the cam 10 may be associated with other pump assemblies. Furthermore, further cams may be provided adjacent to the cam 10, which in turn may be associated with pump assemblies. As a result, depending on the design of the high-pressure pump 1, a radial or series piston pump can be realized.

The pump assembly 15 is arranged substantially in a bore 16 of the pump housing 2. In this case, a projection 17 of the cylinder head 6 protrudes into the bore 16. The pump assembly 15 has a hollow cylindrical plunger body 18, which is guided in the bore 16 along an axis 19. In the plunger body 18, a driving element 20 is arranged, which rests against a shoulder 21 of the plunger body 18 and against the shoulder 21 by a plunger spring 22, which surrounds the approach 17 rudimentary, is applied.

The pump assembly 15 has a pump piston 23. The cylinder head 6 has a cylinder bore 24 which extends along the axis 19 through the projection 17 of the cylinder head 6. The pump piston 23 is guided along the axis 19 in the cylinder bore 24. Here, the pump piston 23 is guided by the driving element 20. The pump piston 23 has a piston foot 25. Further, in the plunger body 18, a roller shoe 26 is inserted. The piston foot 25 is held by the driving element 20 against the roller shoe 26. In the roller shoe 26, a roller 27 of the pump assembly 15 is mounted. In operation, the roller 27 rolls on a running surface 28 of the cam 10, wherein the roller 27 rotates about its axis of rotation 29. As a result of the lifting movement of the cam 10, this causes an alternating actuation of the pump piston 23 in and counter to a conveying direction 30 of the pump assembly 15.

The pump piston 23 of the pump assembly 15 delimits a pump working space 31 in the cylinder bore 24. In this case, filling of the pump working space 31 is made possible by means of an inlet valve 32 in a stroke of the pump piston 23 against the conveying direction 30. In the subsequent actuation of the pump piston 23 in the conveying direction 30, the pressure of the fuel in the pump working chamber 31 increases sharply, via an outlet valve 33 of the high-pressure fuel via a Fuel line 34 can be promoted to a fuel rail or the like.

The plunger body has contact surfaces 35, 36. The roller 27 has side surfaces 37, 38. Here, the side surface 37 of the roller 27 of the contact surface 35 of the plunger body 18 faces. Further, the side surface 38 of the roller 27 of the contact surface 36 of the plunger body 18 faces. By the contact surfaces 35, 36 of the plunger body 18 an axial bearing of the roller 27 is ensured. The radial bearing of the roller 27 via the roller shoe 26th

As a result of the dynamics of the pump drive, there are, inter alia, forces which press the roller 27 against the axial contact surfaces 35, 36 of the tappet body 18. Due to the resulting frictional forces wear on the roller 27 and the plunger body 18 is possible, which occurs specifically in the respective start-up and contact areas between the side surfaces 37, 38 of the roller 27 and the respective associated abutment surfaces 35, 36 of the plunger body 18. In this case, tribological effects can also result in particles that can result in pump damage.

In an interior 39 of the pump housing 2, in which also the cam 10 of the drive shaft 3 is located in operation of the high-pressure pump 1 diesel fuel (diesel oil). This diesel fuel can serve for example for lubricating the bearings 7, 8 here. For this purpose, a suitable lubrication circuit can be provided, so that is located in the interior 39, for example, under low pressure diesel fuel. In this case, diesel fuel can also escape from the pump working chamber 31 into the interior 39 by leakage between the pump piston 23 and the cylinder bore 24. This diesel fuel can be used advantageously for lubricating the bearing of the roller 27 both in the roller shoe 26 and on the stop surfaces 35, 36 of the plunger body 18. Especially for the axial bearing of the roller 27, diesel fuel must be brought into the contact areas between the side surfaces 37, 38 of the roller 27 and the contact surfaces 35, 36 of the tappet body 18 for this purpose. In this embodiment, the roller 27 has both in the region of the side surface 37 and in the region of the side surface 38 each have a plurality of lubricant recesses 40, 41, 42, 43, of which in the in Fig. 1 shown sectional view of the lubricant recesses 40 to 43 are shown and marked. Here, for example, four lubricant recesses 40, 41 may be provided on the side surface 37. Further, four lubricant recesses 42, 43 may be provided on the side surface 38. The lubricant recesses 40 to 43 are preferably arranged uniformly around the rotation axis 29 of the roller 27.

When in the Fig. 1 shown position of the roller 27, the lubricant recesses 40, 42 of the roller 27 can be filled from the interior 39 with diesel fuel. The lubricant recesses 41, 43 are located in the illustrated position of the roller 27 within the receptacle of the plunger body 18 for the roller 27. Here, from the Schmierstoffausnehmungen 41, 43 serve as a lubricant serving diesel oil. Thus, a lubrication is ensured on the one hand between the side surface 37 of the roller 27 and the stop surface 35 of the plunger body 18 and on the other hand between the side surface 38 of the roller 27 and the stop surface 36 of the plunger body 18. As a result, the occurrence of frictional forces that lead to wear or particle formation avoided. As a result, damage to the high-pressure pump 1 over the lifetime can be avoided.

In this embodiment, the lubricant recesses 40 to 43 are designed as blind holes 40 to 43. The blind bores 40 to 43 in this case each extend parallel to the axis of rotation 29 of the roller 27. Thus, regardless of the direction of rotation of the roller 27 a certain lubrication on the Schmierstoffausnehmungen 40 to 43 of the roller 27 is ensured. Thus, the lubrication for supporting the roller 27 is improved. As an additional advantage, possible cavitation can be avoided. Furthermore, the hydrodynamic lubrication between the components is improved.

Fig. 2 shows a roller 27 of a pump assembly 15 of in Fig. 1 illustrated high-pressure pump 1 from the designated II viewing direction according to a second embodiment. In this embodiment, the roller 27 on its side surface 38 lubricant recesses 42, 43, 44, 45, 46, 47, 48, 49. In this embodiment, the lubricant recesses 42 to 49 extend as far as a rolling surface 50 of the roller 27 with which the roller 27 rolls on the running surface 11 of the cam 10.

By the rotation axis 29, a center 29 'of the side surface 38 of the roller 27 is defined. Here, by way of example, a radial half-line 51 is shown which extends from the center point 29 'in a radial direction 52. The radial half-line 51 or the radial direction 52 is in this case oriented perpendicular to the axis of rotation 29. Furthermore, the radial half-line 51 and the radial direction 52 are perpendicular to the rolling surface 50.

The lubricant recesses 42 to 49 are configured in this embodiment as recesses 42 to 49. The recesses 42 to 49 are in this case introduced into the side surface 38 of the roller 27. A region 53 of the side surface 38 about the rotation axis 29 or the center 29 ', in which the roller 27 for axial bearing at least substantially together with the contact surface 36 of the plunger body 18 cooperates, is hereby released. The recesses 42 to 49 thus do not extend into the region 53, but end at an edge 54 of the region 53. The edge 54 is at least approximately circular in shape. The region 53 may, for example, be designed in the shape of a dome.

The lubricant recesses 42 to 49 are not designed exclusively in the radial direction 52 in this embodiment. In this embodiment, a direction of rotation 55 is predetermined for the roller 27. The roller 27 is arranged for this purpose in relation to the direction of rotation of the drive shaft 3 in a suitable manner between the roller shoe 26 and the cam 10. The Schmierstoffausnehmungen 42 to 49 are designed rectilinear in this embodiment. In this case, an axis 56 is illustrated, along which the recess 42 designed as a lubricant recess 42 extends. The axis 56 is in this case inclined relative to the radial half-line 51 by a positive angle 57 in the direction of rotation 55. As a result, the lubricant recess 42 is configured with a profile 56 which lies between the radial direction 52 and the direction of rotation 55. A theoretically conceivable course of the depression 42 in the direction of rotation 55 would in this case lead to an annular depression, for example along the edge 54. Since the course 56 of the depression 42 lies between the radial direction 52 and the direction of rotation 55, in this embodiment the depression 42 extends from the edge 54 of the region 53 to the rolling surface 50 of the roller 27. Thus, the depression 42 can operate fill in the area of the interior 39 of the rolling surface 50 ago with the diesel oil. The diesel oil guided through the depression then enters the region 53 at the edge 54. In this way, in particular the area 53 of the side surface 38 of the roller 27 is wetted with the diesel oil serving as a lubricant.

The other lubricant recesses 43 to 49 are configured according to the lubricant recess 42 and also contribute to the improvement of lubrication. Since the lubricant recesses 42 to 49 are distributed uniformly around the rotation axis 29 on the side surface 38, uniform lubrication in the contact region results during operation.

The lubricant recesses 42 to 49 configured as recesses 42 to 49 can be configured, in particular, by grooves 42 to 49 in the side surface 38. At the other side surface 37 of the roller 27 is a corresponding design provided with lubricant recesses. Thus, the diesel oil at the two side surfaces 37, 38 of the roller 27 in the direction of the stop surfaces 35, 36 are promoted on the rotation axis 29 and thereby improve the lubrication on both sides.

Fig. 3 shows the in Fig. 2 illustrated roller 27 according to a third embodiment. In this embodiment, the lubricant recesses 42 to 45 are configured by blind holes 42 to 45. The blind holes 42 to 45 are here in contrast to the basis of the Fig. 1 described first embodiment, not parallel to the rotation axis 29 of the roller 27 configured. In this embodiment, namely with respect to the direction of rotation 55 of the roller 27 is a directed embodiment of the blind holes 42 to 45 provided on the side surface 38. As an example, an axis 56 of the blind hole 42 is shown. The axis 56 of the blind hole 42 is oriented outwardly in the direction of rotation 55 of the roller 27. In this embodiment, the axis 56 is namely inclined in the direction of rotation 55 by a positive angle 57. If the axis 56 is projected into the plane of the drawing, then the half-line 51 with the axis 56 in this embodiment includes an angle 57 of at least approximately 90 °. However, other angles 57 are conceivable. The axis 56 of the blind hole 42 also has a component of the rotation axis 29. In operation, the blind hole 42 is then filled in the region of the interior 39 of the high-pressure pump 1 with diesel oil. Since the axis 56 is directed component by component against the flow direction, a fuel pressure of the diesel oil builds up in the blind bore 42. By the dammed diesel oil lubrication between the side surface 38 of the roller 27 and the thrust surface 36 of the plunger body 18 can be further improved.

The further blind holes 43, 44, 45 are configured according to the blind hole 42. In each case, the direction of rotation 55 and the center 29 ', which defines the radial direction 52 for the respective blind bore 43, 44, 45, serve as reference variables for the alignment of the blind bores 43, 44, 45.

Fig. 4 shows a plunger body 18 and a roller 27 of a pump assembly 15 of the in Fig. 1 illustrated high-pressure pump 1 according to a fourth embodiment of the designated II viewing direction. In this embodiment, the embodiment is independent of the predetermined direction of rotation 55 for the roller 27th

In this embodiment, 18 lubricant lubricant recesses 60, 61, 62 are provided on the plunger body, which are formed as lubricant channels 60 to 62. specially For example, the lubricant recesses 60 to 62 may be configured as lubricant bores 60 to 62. The lubricant recesses 60 to 62 extend from the abutment surface 36 of the plunger body 18 to an outer side 63 of the plunger body 18. Thus, from the outer side 63 of the plunger body 18 in the region 53 between the side surface 38 of the roller 27 and the inner stop surface 36 of the plunger body 18 diesel oil to lubricate the contact area are performed. As a result, a targeted fuel diversion in the critical starting areas is possible. Accordingly, comparable lubricant recesses for the side surface 37 of the roller 28 may be provided, which extend from the outer side 63 of the plunger body 18 to the inner abutment surface 35 of the plunger body 18.

Fig. 5 shows the in Fig. 1 V section of the pump assembly 15 of the high-pressure pump 1 in a schematic, excerpted sectional view according to a fifth embodiment. In this embodiment, the lubricant recess 61 is not configured parallel to the axis of rotation 29 of the roller 27, but from the inner run-on surface 36 of the plunger body 18 to the outside 63 of the plunger body 18 in the conveying direction 30 of the pump assembly 15 is inclined. As a result, diesel oil is guided through the lubricant channel 61 into the region between the side face 38 of the roller 27 and the stop face 36 of the tappet body 18, in particular during a delivery stroke of the pump assembly 15. This results in a reinforced lubrication just in a delivery stroke, in which the forces acting are large.

It is also possible that the lubricant recesses 60 to 62 are configured parallel to the axis of rotation 29, as for example in the case of the Fig. 4 illustrated embodiment is possible. Furthermore, in the case of the Fig. 5 illustrated embodiment further lubricant recesses 60, 62 may be provided.

As it is in the Fig. 4 is illustrated, the lubricant recesses 60 to 62 are preferably distributed around the rotation axis 29 provided on the plunger body 18. As a result, for example, opens an end 64 of the lubricant recess 16 in the conveying direction 30 above the axis of rotation 29 in the thrust surface 36. The two other Schmierstoffausnehmungen 60, 61 may open at least approximately at the height of the axis of rotation 29 in the thrust surface 36. The plunger body 18 is designed such that the center 29 'of the side surface 38 of the roller 27 is still within the contact surface 36 of the plunger body 18.

The invention is not limited to the described embodiments.

Claims (9)

1. High-pressure pump (1), in particular radial or in-line piston pump for fuel injection systems of air-compressing, auto-ignition internal combustion engines, having at least one pump assembly (15) and having a drive shaft (3) which has at least one cam (10) assigned to the pump assembly (15), wherein the pump assembly (15) has a roller (27), which runs on a contact face (11) of the cam (10), and a tappet body (18) on which the roller (27) is mounted at least axially, wherein at least one lubricant recess (40-49, 60-62) is formed on at least one side face (37, 38) of the roller (27) and/or on at least one run-on face (35, 36), on which the roller (27) is mounted axially by way of its side face (37, 38), of the tappet body (18), characterized in that at least one lubricant recess (42-49) in the form of a depression (42-49) is provided on the side face (37, 38) of the roller (27).
2. High-pressure pump according to Claim 1,
   characterized
   in that the depression (42-49) on the side face (37, 38) of the roller (27) is formed, in the direction of a rolling face (50) of the roller (27), with a profile (56) that lies between a radial direction (52) and a direction of rotation (55) of the roller (27).
3. High-pressure pump according to one of the preceding claims,
   characterized
   in that at least one lubricant recess (40-45) in the form of a blind bore (40-45) is provided on the side face (37, 38) of the roller (27).
4. High-pressure pump according to Claim 3,
   characterized
   in that an axis (56) of the blind bore (42) is oriented outward at least partially in a direction of rotation (55) of the roller (27).
5. High-pressure pump according to Claim 3,
   characterized
   in that the blind bore (40-43) is formed at least approximately parallel to an axis of rotation (29) of the roller (27).
6. High-pressure pump according to one of Claims 3 to 5,
   characterized
   in that, on the side face (37, 38) of the roller (27), there are provided at least four lubricant recesses (40-45) which are in the form of blind bores (40-45) and which open out at the side face (37, 38) of the roller (27) in a manner distributed uniformly about an axis of rotation (29), and in that the roller (27) is mounted axially on the run-on face (35, 36) of the tappet body (18) by way of the side face (37, 38), at least in the region (53) of the axis of rotation (29).
7. High-pressure pump according to one of the preceding claims,
   characterized
   in that, on the tappet body (18), there is provided at least one lubricant recess (60-62) in the form of a lubricant duct (60-62), and in that one end (64) of the lubricant duct (61) opens out at the run-on face (36) of the tappet body (18).
8. High-pressure pump according to Claim 7,
   characterized
   in that the lubricant duct (60-62) is formed so as to be at least partially inclined, from the inner run-on face (36) of the tappet body (18) to an outer side (63) of the tappet body (18), in a delivery direction (30) of the pump assembly (15).
9. High-pressure pump according to Claim 7 or 8,
   characterized
   in that at least three lubricant openings (60-62) in the form of lubricant ducts (60-62) are provided on the tappet body (18), and in that the ends (64) of the lubricant ducts (60-62) open out at the run-on face (36) of the tappet body (18) in a manner distributed about an axis of rotation (29) of the roller (27).

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