WO2020020420A1

WO2020020420A1 - Pump for a motor vehicle, holding device, assembly and method

Info

Publication number: WO2020020420A1
Application number: PCT/DE2019/200083
Authority: WO
Inventors: Stefan Kulzer
Original assignee: Continental Automotive Gmbh
Priority date: 2018-07-23
Filing date: 2019-07-22
Publication date: 2020-01-30
Also published as: DE102018212229A1

Abstract

The invention relates to a pump (1), more particularly a high-pressure fuel pump, for a motor vehicle, having: - a pump housing (2), - a housing cover (3), wherein the pump housing (2) and the housing cover (3) enclose a damper chamber (4), - a damper capsule (5), which is arranged in the damper chamber (4); and - a holding device (8) for the damper capsule (5), characterised in that the holding device (8) is formed in a single piece and arranged in the damper chamber (4), wherein the damper capsule (5) is received in the holding device (8). The invention also relates to a holding device (8), an assembly, and a method.

Description

description

Pump for a motor vehicle, holding device, assembly and method

A pump for a motor vehicle is specified, in particular a high-pressure fuel pump.

Pumps of this type are widely known from the prior art and are used, for example, in motor vehicles in order to be able to inject fuel into a combustion chamber of an internal combustion engine at high pressure. Pumps of this type are set up to apply a pressure to the fuel, which in gasoline internal combustion engines can be, for example, in a range from 150 bar to 600 bar and in diesel internal combustion engines up to 3000 bar or more. Pressure pulsations can occur in the fuel supply system when the pump is operating. In order to dampen these pressure pulsations, a low pressure damper is typically provided in the low pressure area of the pump. Such low pressure dampers are capsules, for example, in the form of dampers.

An object on which the invention is based is to provide a concept for such a pump which enables reliable operation of the pump and contributes to simple assembly.

According to a first aspect, a pump is disclosed, in particular a high-pressure fuel pump, for a motor vehicle. The pump has a pump housing. The pump has a housing cover, the pump housing and the housing cover enclosing a damper chamber. The pump has a damper capsule which is arranged in the damper chamber. The pump also has a holding device for the damper capsule. The holding device is integrally formed and arranged in the damper space, the damper capsule being received in the holding device. By designing the holding device as a one-piece element for holding the damper capsule at a predetermined position in the damper space, the typically used, at least two separate holders or holding elements can be dispensed with. This greatly simplifies the assembly of the damper capsule because the damper capsule is held in the holding device and thus forms a (stem) group with the holding device, which ensures the fixation of the damper capsule during the assembly of the pump. In the case of a multi-part holding device, the assembly is considerably more complex because the components involved have to be aligned with one another, in particular during the assembly of the pump itself. Since the damper capsule is typically held in a preloaded manner, on the other hand, when the components are brought together and the damper capsule is clamped or compressed, multi-part holding device difficulties arise.

The solution according to the invention also helps to avoid moving or moving the components and the multi-part holder, which in the worst case can lead to the damper capsule being in an unintended area by contact with the holding device, the pump housing and / or the function of the housing cover can be impaired. In the holding device according to the invention the clamping of the damper capsule, for example the clamping of the damper capsule in the holding device, takes place only with one part, namely by means of the holding device itself. The holding device itself generates the (minimal) clamping force. The clamping force is determined approximately only by the geometry of the holding device itself, which means that the clamping force can be better, that is to say more defined. The clamping force is not only generated by assembling the holding device with the other components involved, such as the housing cover and the pump housing.

The holding device is arranged in a form-fitting manner between the housing cover and the pump housing. In other words it says the holding device both with the housing cover and with the pump housing in contact (approximately immediately) and is securely arranged between these two elements in an operationally installed state of the pump. The holding device enables the capsule to be positioned in a defined manner. The holding device can also be referred to as a holding device or a spacing device, since it holds the damper capsule at predetermined distances from the housing cover and pump housing. For example, the holding device is manufactured by means of a forming process.

The damper capsule is formed, for example, by two membranes, which are firmly mechanically and sealingly connected to one another in an edge region. For example, the two metal membranes are welded together. The holding device is designed, for example, to hold and clamp the damper capsule in the edge region of the two interconnected membranes. In addition, the holding device supports the membrane connection in the edge area.

According to one embodiment, the damper capsule is held under tension in the holding device, the holding device applying the preload. This contributes to the advantages and functions mentioned. In other words, the damper capsule is clamped or clamped in the holding device.

According to one embodiment, the holding device has a cylindrical section which has a cover section on a side facing the housing cover. The cylin-shaped section is supported with a side facing away from the housing cover on the pump housing and with the cover section in contact with the housing cover. As a result, the Haltevor direction is safely mechanically arranged between the pump housing and the housing cover of the pump. Due to the design with a cylindrical section and cover section, the holding device is to one side, in operation the pump housing facing, essentially open. The capsule is mounted in the holding device via this side.

According to one embodiment, the cover section of the holding device is essentially adapted to a shape of the housing cover. This contributes to a good introduction of force when mounting the housing cover on the pump housing.

In particular, vibrations and pressure pulsations that act on the damper capsule and thus on the holding device can thus be dissipated particularly well via the housing and the housing cover.

According to one embodiment, the holding device has at least one spring element and at least one spacer element, the damper capsule being held under prestress in the holding device between the at least one spring element and the at least one spacer element. For example, the damper capsule, for example with the edge region of the two membranes, is clamped between the spring element and the spacer element. The spacer element can also be referred to as a spacer tab, as a spacer or spacer tab. For the assembly of the damper capsule in the holding device, for example, the spacer element is initially in an assembly position in which the capsule can be inserted into or placed in the holding device. For the final determination in the Haltevor direction, the spacer element is brought into an end position, for example deformed, for example bent. In other words, the spacer element is brought into the final position only after the damper capsule has been placed in the holding device. This embodiment contributes to the advantages and functions mentioned and in particular allows simple and precise assembly.

The holding device preferably has a plurality, in particular a plurality, of such spring elements or corresponding render spacing elements. This helps to make the damper capsule particularly safe and - with regard to Force distribution - is held and recorded particularly homogeneously in the holding device.

According to one embodiment, the at least one spring element is formed in the cover section of the holding device and is bent in the direction of the pump housing. The at least one spacer element is formed on the cylindrical section and is in contact (approximately directly) with the pump housing. For example, the spacer element is shaped out of the cylindrical section, approximately inward, towards a center of the holding device. This enables a particularly effective form of the holding device.

According to one embodiment, the housing cover has a curvature in a direction away from the pump housing and the holding device has a continuous central region, the central region being in contact with the housing cover, in particular in the region of the curvature. The central area is in particular a substantially full-area area of the holding device. In other words, no recess or openings are formed in the central area. The holding device is in contact (approximately directly) with a middle or a corresponding middle area of the housing cover with the middle area. The contact point between the holding device and the housing cover is thus at a point on the housing cover at which, as a rule, maximum deformation takes place during operation due to vibrations and pressure pulsations. Due to the curved design and the contact in this area with the holder, an overall rigidity of the system is increased and vibrations can be effectively reduced.

According to a further aspect, a holding device for a pump according to one of the above embodiments is disclosed. The holding device is formed in one piece and set up to hold a damper capsule of the pump and to hold it in an operationally assembled state of the pump in a damper chamber of the pump. The holding device essentially enables the aforementioned advantages and functions. The embodiments described in connection with the pump can be applied analogously to the holding device.

According to a further aspect, an assembly for a pump according to one of the above embodiments is described. The assembly has a holding device and a damper capsule, which is received in the holding device.

The module essentially enables the aforementioned advantages and functions. In particular, the assembly formed by the holding device and the damper capsule can be easily installed in a high-pressure pump without the need for complex adjustment measures. The above explanations of corresponding further developments of the pump also apply analogously to the assembly.

According to a further aspect, a method for producing an assembly described above is disclosed. The process has the following steps:

- Providing a one-piece holding device for a damper capsule, the holding device having at least one spring element and at least one spacing element, the at least one spacing element being designed in a mounting position in which the damper capsule can be inserted into the holding device,

Inserting the damper capsule into the holding device such that the damper capsule is in contact with the at least one spring element,

- Compression of the at least one spring element by pressing the damper capsule against a spring force of the at least one spring element, and

- Forming, such as bending, of the at least one spacer element into an end position such that the damper capsule is held under pretension between the at least one spring element and the at least one spacer element. The method essentially enables the aforementioned advantages and functions. The further developments explained above also apply analogously or analogously to the method.

The mounting position of the spacer element means that the capsule can be inserted into the holding device without being hindered by the spacer element. For example, in one embodiment of the holding device with a cylindrical section and cover section, the spacer element is designed in such a way that the capsule can be inserted on the open side into the holding device before the spacer element is subsequently deformed in order to secure the capsule against the spring element.

One or more assembly aids can be used to compress the spring element by pressing the damper capsule. These can help, for example, to secure the position of the damper capsule to the spacer element during assembly until it is (plastically) shaped into the end position.

Further advantages, features and further developments result from the following description of an embodiment explained in connection with the figures. Identical, identical and identically acting elements can be provided with the same reference symbols in all figures.

Show it:

Figure 1 is a schematic partial sectional view of a pump, and

FIG. 2 shows a schematic, perspective view of a holding device for a damper capsule according to an exemplary embodiment of the invention,

Figures 3 and 4 are schematic partial sectional views of a pump with the holding device according to Figure 2, and Figure 5 is a schematic flow diagram for producing an assembly from the holding device and a damper capsule.

FIG. 1 shows a schematic partial sectional view of a pump 1, in particular a high-pressure pump, for a motor vehicle. The pump 1 is in particular designed to provide pressures of 350 bar or more. The pump 1 is designed to apply pressure to fuel from a fuel tank (generally from a low-pressure area) in order to subsequently inject it into one or more combustion chambers of an internal combustion engine.

The pump 1 has a pump housing 2 and a housing cover 3. Housing cover 3 and pump housing 2 are mechanically connected fluid-tight and include a damper chamber 4. A damper capsule 5 is arranged in the damper chamber 4. The damper capsule 5 is formed by two metallic membranes 6, which are connected to one another in an edge region 7, in particular are integrally connected by welding. The damper capsule 5 is pressurized inside. The damper capsule 5 is set up the aforementioned

To dampen pressure pulsations. For this purpose, the damper capsule 5 is held at a predetermined position in the damper space 4 by a holding device 8, which is formed by two annular, resilient holding elements. The holding device 8 in particular also functions as a spacing element, so that the

Damper capsule 5 is arranged at a distance from the housing cover 3 and pump housing 2. The pump 1 has an inlet 9 in the form of a connection piece, for example a spout, which opens into a fluid inlet 10 arranged in the housing cover 3. The pump 1 also has a fluid outlet 11 from the damper chamber 4, which opens into an outlet channel 12.

In an operational state, fluid, such as fuel, flows via the inlet 9 and the fluid inlet 10 from the low-pressure region into the damper chamber 4. The fluid flows through the holding device 8 (see openings) and around the damper capsule 5 to the fluid outlet 11 and via the outlet channel 12 to one Inlet valve 13. A piston follows in the flow direction behind the inlet valve 13, via which the fluid in a piston chamber is pressurized and is supplied to a high-pressure area, for example a common rail, via an outlet valve 14. The direction of flow from the inlet 9 to the fluid outlet 11 is additionally indicated by the two arrows. A filter element 15 is arranged in the inlet 9, for example in the area of the fluid inlet 10.

An improved holding device for a pump 1 is described with reference to FIGS. 2 to 4.

FIG. 2 shows the improved holding device 8 in a schematic, perspective view. In contrast to the holding device described with reference to FIG. 1, the holding device 8 according to FIG. 2 is formed in one piece. The holding device 8 has a cylindrical portion 16, on one side of which a cover portion 17 connects. The cover section 17 has a continuous central area 18, that is to say an area in which the cover section 17 is formed essentially over the entire surface and without recesses.

Figures 3 and 4 show detailed sectional views of a pump 1 with the holding device 8 according to Figure 2, wherein the pump 1 can otherwise be constructed analogously to Figure 1. It should be mentioned that the fluid inlet 10 is not arranged in the housing cover 2 as in the pump 1 according to FIG. 1. FIGS. 3 and 4 show that the housing cover 3 has a curvature 18 towards a center. The curvature 19 extends in a direction away from the pump housing 2. The cover portion 17 of the holding device 8 is adapted in its shape to the shape of the housing cover 3, that is to say to the curvature 19. In particular, the cover section 17 is in contact with the central region 18 in contact with a corresponding central region 22 of the housing cover 3.

As can be seen in particular in FIG. 2, spacer elements 20 are provided in the cylindrical section 16 in an annular circumferential manner. In the cover section 17, the Holding device to the spacer elements 20 corresponding, also annular peripheral spring elements 21. The spring elements 21 are of tab-shaped design and are slightly curved inwards. The spacer elements 20 are also radially bent inwards. The damper capsule can be accommodated in the holding device 8 by means of the spring elements 21 and the spacing elements 20, as is illustrated in particular by means of FIGS. 3 and 4.

The damper capsule 5 is clamped in the edge region 7 between the Fe derelemente 21 and the spacer elements 20. In other words, the spring elements 21 apply spring forces to the damper capsule 5 against the spacer elements 20, so that the latter is pretensioned. The damper capsule 5 is thus accommodated in the holding device 8 in a mechanically secure, prestressed manner.

The above-mentioned advantages and functions are made possible by the holding device 8 described. In particular, the damper capsule 5 can be mounted together with the holding device 8 as a preassembled module in the damper chamber 4 between the pump housing 2 and the housing cover 3. In the assembled state, the holding device 8 is supported with the cylindrical section 16 and in particular the spacing elements 20 directly from the pump housing 2, while, as already described, it is supported with the cover section 17 directly on the housing cover 3. In the assembled state, the holding device 8 is thus fixed between the housing cover 3 and the pump housing 2. As a result, the damper capsule 5 is also held indirectly at its desired position. The time-consuming Justa measures for multi-part holding devices can thus be omitted. The damper capsule 5 is braced only via the one-piece holding device 8, the clamping force to be brought about being determined solely by the geometry and design of the holding device 8 itself. Based on the schematic flow diagram of Figure 5, the manufacture of the holding device 8 according to Figures 2 to 4 be described.

In a first step S1, the holding device 8, as shown in FIG. 2, is provided, the spacing elements

20 are not yet bent radially inwards, but are in an assembly position, so that the damper capsule 5 can be inserted into the holding device 8 via the side of the holding device 8 which is open at the bottom.

In a next step S2, the damper capsule 5 is inserted so that it is in direct contact with the spring elements

21 occurs inside the holding device 8.

In a next step S3, the damper capsule 5 is pressed against the spring elements 21 in such a way that the spring elements 21 are bent outwards against a spring force, i.e. towards lid section 17.

In a next step S4, the spacer elements 20 are bent into the end position shown in FIGS. 2 to 4, so that the damper capsule 5 is held under prestress between the spacer elements 20 and the spring elements 21. The force applied to the damper capsule 5 in the step of pressing and compressing can be removed again.

Claims

claims

1. Pump (1), in particular a high-pressure fuel pump, for a motor vehicle, comprising:

- a pump housing (2),

- a housing cover (3), the pump housing (2) and the housing cover (3) enclosing a damper chamber (4),

- A damper capsule (5) which is arranged in the damper chamber (4); and

- A holding device (8) for the damper capsule (5), characterized in that

the holding device (8) is formed in one piece and is arranged in the damper space (4), the damper capsule (5) being accommodated in the holding device (8).

2. Pump (1) according to claim 1, wherein the damper capsule (5) is held under prestress in the holding device (8), the holding device (8) applying the prestress.

3. Pump (1) according to one of the preceding claims, wherein the holding device (8) has a cylindrical section (16) which has a cover section (17) on a side facing the housing cover (3), and wherein the cylindrical section ( 16) with a housing cover (3) facing away from the pump housing (2) is supported and with the cover section (17) in contact with the housing cover (3).

4. Pump (1) according to claim 3, wherein the cover section (17) is essentially adapted to a shape of the housing cover (3).

5. Pump (1) according to claim 2, wherein the holding device (8) has at least one spring element (21) and at least one spacer element (20), the damper capsule (5) between the at least one spring element (21) and the at least one a spacer element (20) is held under prestress.

6. Pump (1) according to claim 5 in conjunction with claim 3 or 4, wherein the at least one spring element (21) in the cover portion (17) is formed and is bent in the direction of the pump housing (2), and wherein the at least one Spacer element (20) is formed on the cylindrical section (16) and is in contact with the pump housing (2).

7. Pump (1) according to one of the preceding claims, wherein the housing cover (3) has a curvature (19) in a direction away from the pump housing (2) and the holding device (8) has a continuous central region (18), the medium area (18) is in contact with the housing cover (3), especially in the area of the curvature.

8. Holding device (8) for a pump (1) according to claim 1, wherein the holding device (8) is formed in one piece and is directed to receive a damper capsule (5) of the pump (1) and in an operationally assembled state of the pump ( 1) in a damper chamber (4) of the pump (1).

9. An assembly for a pump (1) according to claim 1, wherein the assembly has a holding device (8) according to claim 8 and a damper capsule (5) which is received in the holding device (8).

10. A method of manufacturing an assembly according to claim 9, comprising the following steps:

- Providing a one-piece holding device (8) for a damper capsule (5), the holding device (8) having at least one spring element (21) and at least one spacer element (20), the at least one spacer element (20) being designed in an assembly position, in which the damper capsule (5) can be inserted into the holding device (8),

- inserting the damper capsule (8) into the holding device (8) such that the damper capsule (8) is in contact with the at least one spring element (21), - deflection of the at least one spring element (21) by pressing the damper capsule (5) against a spring force of the at least one spring element (21),

- Forming the at least one spacer element (20) into an end position such that the damper capsule (5) is held under prestress between the at least one spring element (21) and the at least one spacer element (20).