WO2017198360A1

WO2017198360A1 - High-pressure fuel pump

Info

Publication number: WO2017198360A1
Application number: PCT/EP2017/056439
Authority: WO
Inventors: Thomas Krumbholz; Soeren Stritzel
Original assignee: Robert Bosch Gmbh
Priority date: 2016-05-19
Filing date: 2017-03-17
Publication date: 2017-11-23
Also published as: KR102288011B1; DE102016208581A1; CN109154266B; KR20190008240A; CN109154266A

Abstract

The invention relates to a high-pressure fuel pump (28), comprising a piston (30) with a piston longitudinal axis (33), a sealing device (54) radially surrounding the piston (30), which seals a fuel side (50) against an oil side (52), wherein the sealing device (54) has a seal (60), a seal carrier (58) in contact with the oil-side end of the seal (56), and a securing element (60) in contact with the fuel-side end of the seal (56), wherein the seal carrier (58) extends at least as far as the securing element (60) on the fuel side when viewed in the direction of the piston longitudinal axis (33), or the seal carrier (58) extends further than an underside (83) of a possible securing-element-side collar (64) directed towards the oil side (52), on the fuel side, when viewed in the direction of the piston longitudinal axis (33), said collar forming a fuel-side end (65) of the securing element (60).

Description

description

title

High-pressure fuel pump

State of the art

The invention relates to a high-pressure fuel pump according to the preamble of claim 1.

In fuel systems, high-pressure fuel pumps are used to

To compress fuel from a pre-pressure to an injection pressure required for fuel injection. Such high-pressure fuel pumps usually have at least one piston, which can be moved axially by means of a drive formed by a cam or an eccentric disc. A radially outwardly disposed on the piston seal, which consists of a usually designed as a deep-drawn element seal carrier and a

Retained fastener separates a fuel side from an oil side, whereby a mixing of fuel and oil is minimized. The seal statically seals against the seal carrier and dynamically against the piston.

From the prior art seal carrier, in which a fastener is used with a fuel side resting on the seal carrier collar known.

Disclosure of the invention

The object of the invention is to provide a high-pressure fuel pump, which has more compact dimensions and reliably seals the fuel side against the oil side. This object is achieved by a high-pressure fuel pump according to claim 1. As a result, height of the high-pressure fuel pump is saved, while the reliability of the gasket of the fuel side is ensured against the oil side.

Preferably, the seal carrier is pot-shaped and surrounds the fastener in the circumferential direction, which is a reliable

Fastening and accurate positioning of the seal ensured.

Advantageously, the fastening element is pot-shaped. As a result, the seal is reliably protected from the action of the piston, which strikes against the fastening element during operation of the high-pressure pump. This prevents the seal from being damaged, and consequently increases the operational safety and life of the high pressure pump.

In a preferred embodiment, the fastening element has a connection with the seal carrier. It is ensured by the connection that the fastener by forces in a

Operating state of the pump acting on the fastener, with respect to the seal carrier along the piston longitudinal axis in the direction of the oil side is immovable. This ensures that the seal is reliably held by the seal carrier and the fastening element during operation of the pump, without it being possible for the seal to be damaged by a displacement of the fastening element.

The fastener may or may not have a collar forming a fuel-side end of the fastener. By a collar is meant a radially outwardly extending portion of material, forming the fuel-side end of the fastener, i. forms the part of the fastener that is furthest towards the

Fuel side extends. If the fastening element comprises such a collar, then it is preferred if the connection is in any case formed in part by a collar of the fastening element, wherein the collar of the fastening element is positively connected to a stop section of the fastening element

Seals carrier supports. This represents a reliable execution of

The above collar can also forces by impact, which be exerted by the piston on the fastener, in

record advantageously and forward to the seal carrier.

In particular, an extension of the collar of the

Fixing element in the radial direction at most 3 mm, preferably at most 2 mm, in particular 1 mm, in particular 0.5 mm. This allows the collar without or by means of small formations in the

Sealing carrier can be sunk. It is also advantageous if the extension of the collar of the fastening element in the radial direction at most 2 times, preferably 1, 5 times, in particular 1 times the

Material thickness of the collar is. With a compact design of the

Fastener can easily customize a suitably sized collar. In an advantageous embodiment, the stop section of the

Seal carrier a chamfer on the seal carrier. Such a chamfer can absorb the forces exerted by the collar on the seal carrier in an advantageous manner, without, for example, causing material removal, which could impair the functioning of the high-pressure pump.

In this case, the chamfer on the seal carrier preferably extends at an angle between 35 and 55, preferably between 40 and 50, in particular at an angle of 45 ° relative to the piston longitudinal axis. Such a chamfer allows a recording of high forces, which are exerted by the collar of the fastener on the seal carrier, and it provides sufficient space for any existing on the fastener collar. Thus, a particularly high resistance to displacement of the fastener and thus a particularly high reliability is guaranteed.

In an advantageous embodiment, the collar of the

Fastening element on an underside a collar-side chamfer which extends at an angle between 35 and 55, preferably between 40 and 50, in particular at an angle of 45 ° relative to the piston longitudinal axis. A collar-side chamfer running in this way enables high forces to be absorbed by the collar of the fastening element on the seal carrier be exercised, and it creates sufficient space, since the collar can be quasi to invest in the seal carrier.

It is particularly preferred if both the seal carrier and the collar of the fastening element have the chamfers just described.

This allows the seal carrier and the collar of the

Attach fastener advantageously together and forces can be transferred very efficient and gentle on the material.

In one embodiment of the high-pressure pump according to the invention, the connection of the fastening element to the seal carrier is a

exclusively non-positive connection. This can be realized in particular by a correspondingly strong press fit between the seal carrier and the fastening element. This results in the advantage that in the manufacturing process of seal carrier and fastener no positive locking elements must be provided, which allows a cost-effective production.

Other features, applications and advantages of the invention will become apparent from the following description of exemplary embodiments of the invention, which are explained with reference to the drawings, wherein the

Features both alone and in different combinations may be important to the invention, without being explicitly referred to again. Show it:

Figure 1 is a simplified schematic representation of a fuel system for an internal combustion engine;

FIG. 2 shows a section of a subregion of a device according to the invention

Fuel high pressure pump;

FIG. 3 shows a section from FIG. 2;

Figure 4 is a representation corresponding to Figure 2 of an alternative

Embodiment of the high-pressure fuel pump according to the invention; Figure 5 is a representation corresponding to Figure 2 of another alternative embodiment of the high-pressure fuel pump according to the invention; and

Figure 6 is a representation corresponding to Figure 2 of another alternative embodiment of the high-pressure fuel pump according to the invention.

FIG. 1 shows a fuel system 10 for a further not shown

Internal combustion engine in a simplified schematic representation. From a fuel tank 12 fuel is actuated via a suction line 14, by means of a Vorforderpumpe 16 and a low pressure line 18 via an inlet 20 of one of an electromagnetic actuator 22

Volume control valve 24 a delivery chamber 26 of a high-pressure fuel pump 28 is supplied. For example, the quantity control valve 24 may be a forcibly disclosed intake valve of the high-pressure fuel pump 28.

The high-pressure fuel pump 28 is designed as a piston pump, wherein a piston 30 can be moved up and down by means of a drive 32 designed as a cam 32 along a piston longitudinal axis 33, which is schematically represented by the arrow with the reference numeral 34. Hydraulically between the delivery chamber 26 and an outlet 36 of the high-pressure fuel pump 28 is formed in the figure 1 as a spring-loaded check valve

Exhaust valve 40 is arranged, which can open to the outlet 36 out.

The outlet 36 is connected to a high pressure line 44 and via this to a

High-pressure accumulator 46 ("common rail") connected. Furthermore, hydraulically between the outlet 36 and the delivery chamber 26 is also a

spring-loaded check valve drawn pressure relief valve 42 is arranged, which can open to the pumping chamber 26 out.

During operation of the fuel system 10, the pre-demand pump 16 delivers fuel from the fuel tank 12 into the low pressure line 18. The quantity control valve 24 may be closed and opened in response to a respective demand for fuel. As a result, the amount of fuel delivered to the high-pressure accumulator 46 is influenced. The electromagnetic actuator 22 is controlled by a control and / or regulating device 48. Figure 2 shows a lower portion 49 of an embodiment of the

The piston 30 extends from a fuel side 50 to an oil side 52. The fuel side 50 is sealed by a sealing device 54 against the oil side 52. The

Sealing means 54 encloses the piston 30 in a circumferential direction U.

A radial direction 55 is represented by a corresponding arrow. The sealing device 54 includes a seal 56, a seal carrier 58 and a fastening element 60. The seal carrier 58 is in the operating position shown at a lower in Figure 2 oil-side end of the seal 56 at this. The fastening element 60 is slightly spaced from a fuel-side end of the seal 56 in FIG. 2 with a U-shaped region 61 in the operating position shown. The seal carrier 58 extends on the fuel side in the direction of

Piston longitudinal axis 33 seen further than the fastener 60. In other words, the fastener 60 is recessed in the seal carrier 58.

The seal carrier 58 has a substantially in the direction of

Piston longitudinal axis 33 extending peripheral wall W on. Oil side to the

Peripheral wall W then and orthogonal to the piston longitudinal axis 33 extends radially inwardly a bottom B with a central opening O, through which the piston 30 extends. On the fuel side, the peripheral wall W goes into a projecting from the piston, so radially outward and orthogonal to the piston longitudinal axis 33 extending upper portion A over. From the radially outer edge of the upper section A extends in the direction of the oil side 52 and along the direction of the piston longitudinal axis a connecting region V. The seal carrier 58 is thus partially pot-shaped with the opening O in the lower part of a pot-like portion TA.

The fastener 60 is also pot-shaped. A

Peripheral wall BW of the fastening element 60 extends in the direction of the piston longitudinal axis 33 and on the oil side, ie at its lower end in the figure, merges into the U-shaped region 61 already mentioned above. The U-shaped portion 61 forms a bottom BB of the fastener 60 with a total orthogonal extent to the piston longitudinal axis 33. He has a central Opening BO, through which the piston 30 extends therethrough. The fastening element 60 is surrounded by the cup-shaped seal carrier 58 in the radial direction 55. In this case, the peripheral wall W of the seal carrier 58 is frictionally connected to the peripheral wall BW of the

Fastener 60 on. The sealing device 54 is above the

Connecting region V of the seal carrier 58 frictionally connected to a

Pump housing 63 attached.

The fastening element 60 has an outwardly extending in the radial direction 55, ie away from the piston and in this case very short collar

64 with a bottom 83 on. A fuel end 65 of the

Fastener 60 is formed by the collar 64. By this is meant that the collar 64 represents that part of the fastener 60 which extends furthest to the fuel side 50. The collar 64 of the fastening element 60 supports the fastening element 60 in a form-fitting manner on a stop section 66 of the seal carrier 58. Of the

Stop section 66 includes a chamfer 68. The chamfer 68 extends at an angle 82 of 45 ° relative to the piston longitudinal axis 33. In the region of a press fit 70 are the fastener 60 and the

Seal carrier 58 in a frictional connection with each other. In the embodiment shown in FIG. 2, therefore, the fastening element 60 has a connection to the seal carrier 58, which comprises a frictional component by the interference fit 70 and a positive-fit component by the support of the collar 64 on the stopper section 66.

Figure 3 shows an area around the collar 64 and the stopper portion 66 in an enlarged view. Here, a (short) extension of the collar 64 of the fastener 60 in the radial direction 55 in Figure 3 carries the

Reference numeral 74. A material thickness of the collar bears the reference numeral

78. The chamfer 68 on the seal carrier 58 extends at an angle 82 relative to the piston longitudinal axis 33. In practice, the angle 82 of the chamfer 68 between 35 ° and 55 °, preferably between 40 ° and 50 °, in particular 45 °, as already above mentioned. The extension 74 of the collar 64 is in practice at most 3 mm, preferably at most 2 mm, in particular 1 mm, in particular 0.5 mm or at most twice, preferably 1, 5 times, in particular 1 times, the material thickness 78 of the collar 64.

FIG. 4 shows an alternative embodiment of the invention

High-pressure fuel pump 28, which differs from that shown in Figures 2 and 3

Embodiment distinguished by the connection between the seal carrier 58 and the fastener 60.

The fastener 60 has no collar 64 in this embodiment. The fuel-side end 65 of the fastener 60 is replaced by a

End face of the fastener 60 is formed. The connection between the seal carrier 58 and the fastening element 60 is an exclusively non-positive connection. In order nevertheless to ensure a reliable operation of the high-pressure fuel pump 28, a fit of the press fit 70 is made stronger than in the one shown in FIG

Embodiment.

FIG. 5 shows a further alternative embodiment of the high-pressure fuel pump 28 according to the invention, which differs from the embodiment shown in FIGS. 2 and 3 in that the seal carrier 58 is the chamfer

68 does not have. The seal carrier 58 therefore extends

seen fuel side in the direction of the piston longitudinal axis 33 as a directed towards the oil side 52 bottom 83 of the collar 64, the seal carrier 58, however, extends fuel side seen in the direction of the piston longitudinal axis 33 not so far as the fastener 60 as a whole. The collar

64 also forms the fuel-side end 65 of the fastener 60 in this embodiment.

FIG. 6 shows a further alternative embodiment of the high-pressure fuel pump 28 according to the invention, which differs from that shown in FIG

Embodiment differs in that the collar 64 at its

Bottom 83 has a chamfer 84. The chamfer 84 extends at an angle 86 of 45 ° relative to the piston longitudinal axis 33. The seal carrier 58 extends in this embodiment, while the fuel side in the direction of the piston longitudinal axis 33 seen as the oil side 52 directed towards

Bottom 83 of the collar 64, the seal carrier 58, however, extends seen fuel side in the direction of the piston longitudinal axis 33 not so far as the fastener 60 total. The collar 64 also forms the fuel-side end 65 of the fastening element 60 in this embodiment. During operation of the high-pressure fuel pump 28, the piston 30 moves up and down along the piston longitudinal axis 33, represented by the arrow 34 in FIGS. 2 and 4. The U shaped portion 61 of the fastener 60 that a step S of the piston 30 impacts the seal 56. The

Fastener 60 forms with its U-shaped portion 61 also has an axial stop of the seal 56 in operation of the fuel high pressure pump 28 and a captive for the piston 30 during transport or during storage of the high-pressure fuel pump 28th

The connection between seal carrier 58 and fastener 60 prevents the fastener 60 in the direction of the piston longitudinal axis

33 slips toward the oil side 52 out. The connection is both in the

Embodiment according to Figures 2 and 3 and in the embodiment of Figure 4 executed strong enough to such slippage in each operating condition of the high-pressure fuel pump 28, i. for all occurring during operation of the pump forces acting on the fastener 60 exclude. The forces acting on the fastening element 60 in the operating state of the high-pressure fuel pump 28 are predominantly exerted on the fastening element 60 by the piston 30 via the seal 56.

Claims

High-pressure fuel pump (28), comprising a piston (30) with a piston longitudinal axis (33), a radially surrounding the piston (30)

Sealing means (54) sealing a fuel side (50) against an oil side (52), the sealing means (54) including a seal (60), a

A seal carrier (58) which abuts against the oil-side end of the seal (56) and a fastening element (60) which abuts against the fuel-side end of the seal (56), characterized in that the

Seal carrier (58) seen fuel side in the direction of the piston longitudinal axis (33) extends at least as far as the fastener (60), or that the seal carrier (58) fuel side seen in the direction of the piston longitudinal axis (33) extends further as one to the oil side (52 ) directed bottom (83) of any fastener-side collar (64) which forms a fuel-side end (65) of the fastener (60).

High-pressure fuel pump (28) according to claim 1, characterized in that the seal carrier (58) is partially pot-shaped and surrounds the fastening element (60) in the circumferential direction (U).

High-pressure fuel pump (28) according to one of claims 1 or 2, characterized in that the fastening element (60) is pot-shaped.

High-pressure fuel pump (28) according to one of the preceding

Claims, characterized in that the fastening element (60) has a connection with the seal carrier (58), wherein the

Connection is such that the fastening element (60) by forces in an operating state of the high-pressure fuel pump (28) on the

Fastening element (60) act with respect to the seal carrier (58) along the piston longitudinal axis (33) in the direction of the oil side (52)

is immovable.

5. high-pressure fuel pump (28) according to claim 4, characterized in that the connection in any case partially through the collar (64) of the

Fastener (60) is formed, wherein the collar (64) of the

Fastening element (60) positively supported on a stop portion (66) of the seal carrier (58).

High-pressure fuel pump (28) according to claim 5, characterized in that an extension (74) of the collar (64) of the fastening element (60) in the radial direction (55) at most 3 mm, preferably at most 2 mm, in particular 1 mm, in particular 0.5 mm.

7. high-pressure fuel pump (28) according to claim 5 or 6, characterized

in that the extension (74) of the collar (64) of the

Fixing element (60) in the radial direction (55) is at most 2 times, preferably 1, 5 times, in particular 1 times the material thickness (78) of the collar (64).

High-pressure fuel pump (28) according to one of claims 5 to 7, characterized in that the abutment portion (66) of the seal carrier (58) comprises a chamfer (68) on the seal carrier (58), preferably at an angle (82) between 35 and 55 , preferably between 40 and 50, in particular at an angle (82) of 45 ° with respect to the piston longitudinal axis (33) runs, or.

High-pressure fuel pump (28) according to one of claims 5 to 8, characterized in that the collar (64) on its underside (83) comprises a chamfer (84) at an angle (86) between 35 and 55, preferably between 40 and 50, in particular at an angle (86) of 45 ° relative to the piston longitudinal axis (33).

10. High-pressure fuel pump (28) according to claim 4, characterized in that the connection of the fastening element (60) with the seal carrier (58) is an exclusively non-positive connection (70).