WO2010130496A1

WO2010130496A1 - Plug-in pump

Info

Publication number: WO2010130496A1
Application number: PCT/EP2010/053692
Authority: WO
Inventors: Markus Schetter
Original assignee: Robert Bosch Gmbh
Priority date: 2009-05-13
Filing date: 2010-03-22
Publication date: 2010-11-18
Also published as: DE102009003057A1

Abstract

A plug-in pump (1), which serves in particular for use in fuel injection systems of air-compressing, auto-ignition internal combustion engines, has at least one cylinder head (3) which holds at least one pump assembly (13). Here, the cylinder head (3) has a shank (4). The pump assembly (13) comprises a cylinder bore (5) which extends in sections through the shank (4), a pump piston (6) which is arranged in sections in the cylinder bore (5), and a tappet body (31). The tappet body (31) is connected to the pump piston (6). Also provided is a sleeve (30) which surrounds the tappet body (31) and the shank (4) in sections. Furthermore, the tappet body (31) has a projection (33) on its outer side (32). The sleeve (30) engages behind the projection (33) of the tappet body (31) so as to form a captive retention means.

Description

5Beschreibung

Title plug-in pump

l oStand of technology

The invention relates to a plug-in pump. Specifically, the invention relates to the field of fuel injection systems of air compressing, self-igniting internal combustion engines.

From DE 10 2004 028 999 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 element. In this case, a driven in a lifting movement, in a cylinder bore of a pump housing part slidably guided pump piston is provided which limits a pump working space in the cylinder bore. Via a suction valve the pump

Working space with a suction stroke of the pump piston can be filled with fuel.

The high-pressure pump known from DE 10 2004 028 999 A1 has the disadvantage that adjustments of the high-pressure pump are not possible or at least costly.

25Offenbarung the invention

The plug-in pump according to the invention with the features of claim 1 has the advantage that a wider range of applications is possible and in particular adaptations to different requirements are possible. Specifically, a plug-in pump can be created which can be integrated into an internal combustion engine without an additional housing.

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

It is advantageous that the plunger body protrudes from the sleeve at one end of the sleeve and / or that a roller shoe inserted into the plunger body protrudes at the end of the sleeve the sleeve protrudes. As a result, in the mounted state of the plug-in pump, an advantageous contact of a roller, which is received by the roller shoe, on a cam of a drive shaft or the like is made possible. The end of the sleeve in this case has a sufficient distance from the cam and may not project or only slightly into a space provided for the 5Antriebswelle space.

It is advantageous that the projection of the tappet body provided on the outside of the tappet body is arranged at a distance from an open end of the tappet body on the outside of the tappet body. As a result, an advantageous form-fitting connection is made possible between the sleeve and the tappet body. Furthermore, an assembly of the plunger body is facilitated in the sleeve and allows any necessary disassembly.

It is advantageous that the projection provided on the outer side of the tappet body is designed as a circumferential projection at least in sections, and / or that the projection provided on the outer side of the tappet body is configured as a latching nose-shaped projection. In this case, it is further advantageous that the projection provided on the outer side of the tappet body is designed as a projection extending at least approximately 180 ° on the outer side. As a result, assembly of the tappet body into the sleeve is facilitated and a reliable positive connection ensured. The sleeve can thereby serve advantageously as a captive for the components, in particular the plunger body and the roller shoe.

It is also advantageous that the sleeve engages behind the projection of the plunger body at one end of the sleeve. Here, it is also advantageous that the plunger body has at the end of the sleeve provided in a side wall of the sleeve recess. In addition, it is advantageous that the recess provided in the side wall of the sleeve extends circumferentially at least approximately 180 ° about the circumference of the side wall and / or that the recess provided in the side wall of the sleeve is open at the end of the sleeve. 30Hereby an assembly of the plug-in pump can be facilitated. Specifically, the plunger body can be used with the roller shoe inserted into the plunger body via the recess in the sleeve. By subsequently rotating the plunger body by, for example, 180 °, it may then be possible to position the projection of the plunger body with respect to the sleeve, so that the sleeve engages behind the projection of the plunger body in the sense of a captive securing device. It is also advantageous that the sleeve has at least one fastening element on an end facing the cylinder head, that the shaft of the cylinder head has an attachment point associated with the fastening element, and that the sleeve is positively connected to the shaft by the fastening element at the attachment point. 5This sleeve can be held against rotation on the shaft of the cylinder head. Further, joining methods such as pressing or welding may be used to connect the sleeve to the shaft.

It is advantageous that the plunger body has an eccentric receiving bore, that l or pump piston at one end facing the plunger body has a collar and that guided with its collar by the eccentric receiving bore of the plunger body pump piston is positively connected in the centered state with the plunger body. In this way, an advantageous holding function of the pump piston can be configured, which allows a simple assembly and a reduction of the components. 15

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:

2 OFig. 1 is a plug-in pump in a schematic, partial sectional view according to an embodiment of the invention and

Fig. 2 shows the designated in Fig. 1 with Il section of the plug-in pump of the embodiment in a three-dimensional representation.

25

Fig. 1 shows a plug-in pump 1 in a schematic, partial sectional view according to an embodiment. The plug-in pump 1 has a low-pressure unit 2 and a cylinder head 3. In this case, the cylinder head 3 can be inserted in an internal combustion engine or in a housing of a high-pressure pump. Especially suitable is the

30Steckpumpe 1 for fuel injection systems of air-compressing, self-igniting internal combustion engines. A preferred use of the plug-in pump 1 is for a fuel injection system with a fuel rail, which stores diesel fuel under high pressure. However, the plug-in pump 1 according to the invention is also suitable for other applications.

35 The cylinder head 3 has a shaft 4, which protrudes in the mounted state in a bore, not shown, of the internal combustion engine or a housing of a high-pressure pump. In the shaft 4, a cylinder bore 5 is formed, in which a pump piston 6 is guided. The pump piston 6 is operable by a cam or the like via a roller 7 and a roller shoe 8 which receives the roller 7. For example, the cam may be part of a drive shaft. The roller 7 runs in operation on the cam, wherein the roller 7 is mounted in the roller shoe. During operation, the pump piston 6 thereby moves back and forth along an axis 9 of the cylinder bore 5 in the cylinder bore 5.

10

The pump piston 6 defines a pump working chamber 10 of the cylinder bore 5. During a suction stroke of the pump piston 6, fuel is fed into the pump working chamber 10 via a suction valve 11. During a subsequent delivery stroke, fuel is pumped out of the pump working chamber 10 via an outlet valve 12 to a fuel distributor strip or the like.

The pump working space 10, the pump piston 6, the roller shoe 8 and the roller 7 mounted in the roller shoe 8 are components of a pump assembly 13. The suction valve 11 and the outlet valve 12 are assigned to the pump assembly 13.

20

In this embodiment, the low-pressure unit 2 has a housing 15 which is fixed to the cylinder head 3, for example via suitable connecting screws. In addition, the low-pressure unit has an inlet connection 17, via which fuel can be guided into the housing 15. In the housing 15, a fuel channel 18 is designed, which as

25 branched fuel channel 18 is executed. The fuel channel 18 connects the inlet nozzle 17 with a recess 19 of the housing 15 of the low-pressure unit 2. Here, a metering unit 20 is inserted into the housing 15. The fuel channel 18 formed in the housing 15 connects the inlet nozzle 17 by means of the metering unit 20 with the recess 19 of the housing 15th

30

At the low pressure unit 2, a return pipe 21 is also provided. In this case, a connected to the housing 15 relief valve 22 is provided, which is inserted into a stepped bore 23 of the housing 15. The stepped bore 23 adjoins the branched fuel channel 18. From the inlet port 17 can fuel over the branched

35 fuel channel 18 are led to the spill valve 22, so that a Druckeinstel- is possible. A diverted amount of fuel is returned via the return pipe 21 to a tank or the like.

The plug-in pump 1 has a sleeve 30. Furthermore, the pump assembly 13 has a SStößelkörper 31, which is guided on the shaft 4. The sleeve 30 encloses the shaft 4 and the plunger body 31 in sections. The plunger body 31 has on its outer side 32 a projection 33. The sleeve 30 has a collar 34 with which the sleeve 30 engages behind the projection 33. As a result, a captive for the plunger body 31 is formed.

The collar 34 is provided in this embodiment at one end 35 of the sleeve 30. At the end 35 of the plunger body 31 protrudes from the sleeve 30. In this case also projects into the plunger body 31 roller shoe 8 protrudes at the end 35 of the sleeve 30. The recorded by the roller shoe 8 roller 7 can thereby advantageously on a cam or be arranged without the sleeve 30 having such a positioning

Disruption impeded.

The plunger body 31 has an open end 36, on which the roller 7 protrudes beyond the end 36 of the plunger body 31 from the roller shoe 8. The projection 33 of the tappet body 31 is spaced from the open end 36 on the outer side 32 of the tappet body 2031. As a result, a reaching behind the projection 33 of the plunger body 31 of the sleeve 30 at a certain distance from the open end 36 by the collar 34 of the sleeve 30 is made possible.

The projection 33 provided on the outer side 32 of the tappet body 31 is designed as a projection 33 which extends circumferentially in sections. In this case, the projection 33 is designed latch-shaped. The projection 33 can rotate with respect to the axis 9, for example by 180 ° on the outside 32.

The sleeve 30 has attachment elements 38, 39 on an end 37 of the sleeve 30 facing the cylinder head 3. Further, the shaft 4 of the cylinder head 3 mounting points 40, 41, which are formed in this embodiment by recesses 40, 41. The fastening points 40, 41 are assigned to the fastening elements 38, 39. At the fastening points 40, 41, the sleeve 30 by means of the fastening elements 38, 39 is positively connected to the shaft 4. In this case, a cohesive connection can also be provided. Such a connection of the sleeve 30 with the shaft 4 is designed to be non-rotatable, so that the sleeve 30 is not or only slightly about the axis 9 with respect of the shaft 4 is rotatable. To design such a connection, disposal methods such as pressing or welding may be used. As positive elements snap or hook elements or a bayonet lock are possible.

Between the shaft 4 of the cylinder head 3 and the pump piston 6, a sealing element 42 made of polytetrafluoroethylene is provided, which reduces leakage through the gap between the pump piston 6 and the cylinder bore 5 from the pump working space 10. As a result, an entry of fuel into an engine oil and vice versa can be minimized. The sealing element 42 is fixed at the lower end of the cylinder bore 5 of the shaft 4 by pressing in and secured axially by a presser 43. An optionally occurring leakage of high pressure fuel to the sealing element 42 is returned to the suction valve 1 1 via a drainage hole 44 formed in the cylinder head 3.

Furthermore, a plunger spring 45 is provided, which is supported on the one hand on the shaft 4 of the cylinder head 3 and on the other hand on a contact surface 46 of the plunger body 31. The contact surface 46 of the plunger body 31 is at least partially formed on the projection 33 of the plunger body 31.

When mounting the plug-in pump 1, the pump piston 6 can be advantageously connected to the plunger body 31. Here, the pump piston 6 is connected to the plunger body 31 prior to insertion into the cylinder bore 5. For this purpose, the plunger body 31 has a disc-shaped intermediate piece 47, wherein the intermediate piece 47 has an eccentric receiving bore 48. The eccentric receiving bore 48 allows the

25Pumpenkolben 6 is guided with its collar 49 through the receiving bore 48 of the intermediate piece 47. This implementation is possible with respect to the plunger body 31 with an offset from the axial center position arrangement of the pump piston 6. Subsequently, the pump piston 6 can be brought into the axial basic position shown in FIG. 1, in which the intermediate piece 47 tightly surrounds the pump piston 6, so that the

30Bund 49 comes in positive connection with the intermediate piece 47. The collar 49 is then clamped between the intermediate piece 47 and the inserted into the plunger body 31 roller shoe 8.

FIG. 2 shows the detail of the plug-in pump 1 of the embodiment shown in FIG.

35 example in a spatial representation. Here, the sleeve 30 and the plunger body 31 are shown in a position during assembly. The projection 33 extends partially over the circumference of the tappet body 31. In this case, a height of the projection 33 may vary circumferentially. The plunger body 31 has at the end 35 of the sleeve 30 has a recess 50, via which the plunger body 31 is inserted into the sleeve 30. Here, after insertion, a rotation of the plunger body 31 about the axis 9 relative to the sleeve 30 take place. 5Drive the projection 33 is rotated from the recess 50 of the sleeve 30 in the sleeve 30, so that the projection 33 is associated with the collar 34 of the sleeve 30. As a result, a captive is formed. The captive is particularly during transport and installation of the plug-in pump 1 of advantage. Furthermore, a rotation can be ensured. In this embodiment, the recess 50 is formed in a side wall 51 l O, wherein the recess 50 of the sleeve 30 extends circumferentially about 180 ° about the circumference of the side wall 51. Further, the recess 50 extends in the side wall 51 up to the end 35 of the sleeve 30, so that the collar 34 extends corresponding to only about 180 ° about the circumference of the side wall 51.

During assembly, the plunger body 31, together with the roller shoe 8 and the roller 7, can be inserted obliquely into the sleeve 30 via the recess 50. In the inserted state, the projection 33 is initially in the region of the recess 50 of the side wall 51 and is thus not yet associated with the collar 34. Then, the pump piston 6 can be eccentrically inserted in the axial direction in the plunger body 31 so that the collar

2049 is guided by the eccentric receiving bore 48 of the intermediate piece 47 and comes into contact with the roller shoe 8. Thereafter, the pump piston 6 is axially aligned, that is moved into the center of the intermediate piece 47. Due to the eccentric receiving bore 48 in the intermediate piece 47, a entrainment is ensured at a suction stroke at this centered position of the pump piston 6.

25

Subsequently, the plunger spring 45 can be used. Then, the entire package comprising the sleeve 30, the roller shoe with the roller 7, the pump piston 6 and the plunger spring 45 can be completely mounted on the shaft 4 of the cylinder head 3. Here, for example, designed as locking elements fasteners 38, 39 to the

30 fastening points 40, 41 engage the shaft 4. By turning the plunger body 31, the projection 33 is assigned to the collar 34, so that a captive is formed. It is also possible that the plunger body 31 is rotated so far that an anti-rotation is formed for a transport. For this purpose, the projection 33 may have an increasing extent in the radial direction.

35 The plug-in pump 1 can have both an outer and an internally guided plunger body 31. Furthermore, the sleeve 30 can be designed as a sheet-metal deep-drawn part with two fastening elements 38, 39 configured as latching lugs.

In the described embodiment, there is the advantage that a non-destructive disassembly for a diagnosis is possible. Furthermore, components can be saved, since the sleeve 30 performs several functions, such as the function of the captive and the entrainment of the pump piston 6 in a suction stroke.

The invention is not limited to the embodiments described.

Claims

5Ansprüche

1. plug-in pump (1), in particular for fuel injection systems of air-compressing, self-igniting internal combustion engines, with a cylinder head (3) receiving at least one pump assembly (13), wherein the cylinder head (3) has a shaft (4), where the Pump assembly (13) has a cylinder bore (5) extending at least partially through the shaft (4), an at least partially in the cylinder bore (5) arranged pump piston (6) and a plunger body (31), at least indirectly with the pump piston (6) is connected, wherein a sleeve (30) is provided which at least partially surrounds the plunger body (31) and the shaft (4), wherein the l5 ram body (31) on its outer side (32) has at least one projection (33) and wherein the sleeve (30) engages behind the projection (33) of the plunger body (31).

2. plug-in pump according to claim 1, characterized

20 that the plunger body (31) at one end (35) of the sleeve (30) protrudes from the sleeve (30) and / or that in the plunger body (31) inserted roller shoe (8) at the end (35) of the sleeve ( 30) protrudes from the sleeve (30).

3. plug-in pump according to claim 1 or 2,

Characterized in that the projection (33) of the tappet body (31) provided on the outer side (32) of the tappet body (31) is spaced from an open end (36) of the tappet body (31) on the outer side (32) of the tappet body (31). is arranged.

304. Plug-in pump according to one of claims 1 to 3, characterized in that on the outer side (32) of the plunger body (31) provided projection (33) is designed as at least partially circumferential projection (33) and / or that on the outside (32) of the plunger body (31) provided projection (33) as latching nose

35förmiger projection (33) is configured.

5. Plug-in pump according to claim 4, characterized in that on the outer side (32) of the plunger body (31) provided projection (33) as at least about 180 ° on the outer side (32) circumferentially the projection (33) is formed 5ist.

6. Plug-in pump according to one of claims 1 to 5, characterized in that the sleeve (30) the projection (33) of the plunger body (31) at one end (35) of the sleeve Ose (30) engages behind.

7. Plug-in pump according to claim 6, characterized in that the plunger body (31) at the end (35) of the sleeve (30) in a side wall (51) of the sleeve I5 (30) provided recess (50).

8. Plug-in pump according to claim 7, characterized in that in the side wall (51) of the sleeve (30) provided recess (50) extends circumferentially at least about 180 ° about the circumference of the side wall (51) and / or in that the recess (50) provided in the side wall (51) of the sleeve (30) is open at the end (35) of the sleeve (30).

9. Plug-in pump according to one of claims 1 to 8, 25dadurch in that the sleeve (30) at one of the cylinder head (3) facing the end (37) at least one fastening element (38, 39), that the shaft (4) of the cylinder head (3) has an attachment point (40, 41) facing the attachment element (38, 39), and in that the sleeve (30) is positively connected to the shaft (4) by the attachment element (38, 39) at the attachment point (40, 41) ) connected is.

10. Plug-in pump according to one of claims 1 to 9, characterized in that the plunger body (31) has an eccentric receiving bore (48) that the 35Pumpenkolben (6) at a the plunger body (31) facing the end of a collar (49) and that with his collar (49) through the eccentric receiving bore (48) the plunger body (31) guided pump piston (6) in the centered state is positively connected to the plunger body (31).