GB2481683A

GB2481683A - Pump pulsation damper

Info

Publication number: GB2481683A
Application number: GB1110368.6A
Authority: GB
Inventors: Wolfgang Schuller
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2010-06-29
Filing date: 2011-06-17
Publication date: 2012-01-04
Anticipated expiration: 2031-06-17
Also published as: CN102312808B; GB201110368D0; DE102010030627A1; FR2961863A1; GB2481683B; CN102312808A

Abstract

A pulsation damper 3 for a fluid pump 1 has an elastic spring element comprising a damper pot 10 with a base body 14 of e.g. injection moulded plastics or metal in which there are formed interspaces 14.1 which are filled with an elastic filling compound 20 which performs the function of the spring element so that, upon a movement of the base body 14 brought about by a pressure pulsation, an enclosed air volume 18 is compressible for absorption of the pressure pulsation. The elastic compound may be an elastic plastics material e.g. ethylene-propylene-diene monomer. The damper may form the return spring for a pump valve and have a bottom 16 supporting a spherical 9, part spherical (9 Fig. 2) or flat (9 Fig. 3) closure element. The other end may form a dimensionally stable region 12 for press fitting or caulking.

Description

Pulsation damper element for a fluid pump and associated fluid pump

Prior art

The invention relates to a pulsation damper element for a fluid pump of the generic type of independent Claim 1 and also to an associated fluid pump having such a pulsation damper element.

Fluid pumps, which are designed for example as piston pumps, are used in vehicles with hydraulic or electrohydraulic vehicle brake systems, preferably as return pumps, for selectively lowering or raising a brake pressure in the wheel brake cylinders, and as a result the brake pressure in the wheel brake cylinders can be regulated. Such regulation can be performed, for example, in an anti-lock brake system (ABS), a traction control system (TC system), and a driving-dynamics control system, etc. A conventional piston pump is described, for example, in the laid-open patent application DE 10 2007 047 417 Al and comprises a piston assembly, an inlet valve, an outlet valve and a cylinder. The inlet valve is generally configured as a nonreturn valve. The outlet valve is likewise configured as a spring-loaded nonreturn valve and is arranged in a cover element of the piston pump. The outlet valve is opened when a pressure in a compression chamber is greater than a spring force, acting on an outlet valve sealing element of the outlet valve, of an outlet valve spring, as a result of which the outlet valve sealing element is pressed out of an outlet valve seat arranged at an outlet opening of the cylinder.

To reduce the pressure pulsations, conventional piston pumps can be equipped with a pulsation damper element which has a membrane made of rubber or is designed as a rubber/steel part.

Disclosure of the invention

The pulsation damper element according to the invention having the features of the independent Claim 1 has the advantage over the prior art that pressure peaks can be optimally absorbed in a small constructional space by the proposed design, so that pressure pulsations can be reduced advantageously both in the low-pressure range and in the high-pressure range. The pulsation damper element deforms already at very low pressures and therefore also responds quickly and precisely already at low pressure pulsations. Owing to the bellows base body, embodiments of the pulsation damper element according to the invention can, however, also endure with regard to strength/fatigue strength in the high-pressure range, the elastic behaviour of the bellows base body being designed optimally for the absorption of pressure pulsations.

Overall, the result is advantageously a small installation space and cost-effective and simple production of the pulsation damper element according to the invention.

A pulsation damper element according to the invention for a fluid pump comprises a damper pot with a bellows base body, in which there are formed interspaces which are filled with an elastic filling compound which performs the function of the spring element, so that, upon a movement of the bellows base body brought about by a pressure pulsation, an enclosed air volume is compressible for absorption of the pressure pulsation. The elastic behaviour of the damper pot can be predetermined advantageously by the number and/or size of the interspaces or by the type of elastic filling material used.

The pulsation damper element according to the invention may be installed, for example, in a pump housing and/or in a cover, preferably in an outlet valve cover, of a fluid pump.

Owing to the measures and developments set out in the dependent claims, advantageous improvements of the pulsation damper element specified in the independent Claim I and of the fluid pump specified in the independent Claim 9 are possible.

It is particularly advantageous, to form the damper pot, for the bellows base body to be closed off at one end by a pot bottom. Advantageously, the pot bottom can be designed as a carrier for a sealing element and/or as a sealing element of a fluid valve, preferably an outlet valve of a fluid pump. The sealing element can be designed, for example, as a sealing sphere and/or as a sealing spherical cap and/or as a sealing plate. In this case, the sealing element can be fixedly or movably connected to the pot bottom designed as a carrier or be integrally formed on the pot bottom. These measures advantageously allow a particularly compact design of the fluid pump, since the pulsation damper element can be integrated, for example, into the constructional space of the outlet valve of the fluid pump. Improved utilisation of the available constructional space results when the pulsation damper element also performs the function of a return spring for the outlet valve of the fluid pump.

In an advantageous refinement of the pulsation damper element according to the invention, at the other end, the bellows base body has a stable end region which can be used, upon assembly of the pulsation damper element, advantageously as an effective diameter for a press-in operation and/or a caulking operation.

In a further advantageous refinement of the pulsation damper element according to the invention, the damper pot is injection-moulded from plastic or formed from metal, preferably steel. An elastic plastic, preferably an ethylene-propylene-d iene monomer, can be used as the filling compound in the interspaces of the bellows base body.

In an advantageous refinement of the fluid pump according to the invention, the pulsation damper element is designed as a return spring element of the outlet valve of the fluid pump.

The pulsation damper element can thus be used as a pure damper element for absorption of pressure pulsations or as a return spring, damper and/or sealing element which can be mounted in the outlet valve cover. The pulsation damper element can then be completely mounted directly in the fluid pump or externally in the housing or pump cover.

Advantageous embodiments of the invention are illustrated in the drawings and described below. In the drawings, identical reference symbols designate components and elements that perform the same or analogous functions.

Brief description of the drawings

Fig. 1 shows a schematic illustration of a detail of a fluid pump in the region of an outlet valve having a first exemplary embodiment of a pulsation damper element according to the invention.

Fig. 2 shows a schematic sectional illustration of a second exemplary embodiment of the pulsation damper element according to the invention from Fig. 1.

Fig. 3 shows a schematic sectional illustration of a third exemplary embodiment of the pulsation damper element according to the invention from Fig. 1.

Embodiments of the invention As can be seen from Fig. 1, a pulsation damper element 3 according to the invention for a fluid pump 1 comprises a damper pot 10 with a bellows base body 14, in which there are formed according to the invention interspaces 14.1 which are filled with an elastic filling compound 20. In this case, the filling compound 20 which fills the interspaces 14.1 performs the function of the spring element, so that, upon a movement of the bellows base body 14 brought about by a pulsation of the pressure P, an enclosed air volume 18 is compressed for absorption of the pressure pulsation.

In the exemplary embodiment illustrated, the pulsation damper element 3 is integrated in a cover 5 of an outlet valve of the fluid pump 1 and additionally performs the function of a return spring for a sealing element 9 of the outlet valve, the sealing element 9 sealing or freeing an outlet from a pump cylinder 7 of the fluid pump 1.

As can further be seen from Fig. 1, to form the damper pot 10, the bellows base body 14 is closed off at one end by a pot bottom 16 which is designed as a carrier 16 for the sealing element 9 of the outlet valve of the fluid pump 1. In the first exemplary embodiment illustrated, the sealing element 9 is designed as a sphere, it being possible for the pot bottom 16 to have, for example, a corresponding indentation for movably guiding the sealing element 9 designed as a sphere.

At the other end, the bellows base body 14 has a stable end region 12 which can be used, upon assembly of the pulsation damper element 3, as an effective diameter 12.1 for a press-in operation and/or a caulking operation. In this case, the stable end region 12, which is designed for example as a protruding shoulder, is fluid-tightly pressed in at a press-in region 5.1 of the outlet valve cover 5. Alternatively, the stable end region 12 can be fluid-tightly caulked to the outlet valve cover 5 at a caulking region.

The second exemplary embodiment of the pulsation damper element 3' illustrated in Fig. 2 differs from the first exemplary embodiment of the pulsation damper element 3 from Fig. 1 only in that a sealing element 9', designed as a sealing spherical cap, is fixedly connected to the pot bottom 16', designed as a carrier, of the damper pot 10'. As a result, repeated description of the functionally identical components can be dispensed with here.

The third exemplary embodiment of the pulsation damper element 3" illustrated in Fig. 3 differs from the first exemplary embodiment of the pulsation damper element 3 from Fig. 1 only in that the pot bottom 16" itself is designed as a sealing element 9" in the form of a sealing plate. As a result, repeated description of the functionally identical components can also be dispensed with here.

The damper pot 10, 10', 10" can, for example, be injection-moulded from plastic or formed from metal, preferably steel. The filling compound 20 used in the interspaces 14.1 of the bellows base body 14 can, for example, be an elastic plastic, preferably an ethylene-propylene-diene monomer.

Embodiments of the present invention reduce the pressure pulsations by using the bellows base body with interspaces which are filled with an elastic filling material and allow a bellows movement both in the low-pressure range and in the high-pressure range. At low pulsations, the pulsation damper element responds quickly and precisely and owing to its design is also protected from damage in the high-pressure range.

Pressure peaks can thus be optimally absorbed in a small constructional space directly in the pump or outside.

Claims

Claims 1. Pulsation damper element for a fluid pump 1 having an elastic spring element (20), characterised by a damper pot (10, 10', 10") with a bellows base body (14), in which there are formed interspaces (14.1) which are filled with an elastic filling compound (20) which performs the function of the spring element, so that, upon a movement of the bellows base body (14) brought about by a pressure pulsation, an enclosed air volume (18) is compressible for absorption of the pressure pulsation.
2. Pulsation damper element according to Claim 1, characterised in that, to form the damper pot (10, 10', 10"), the bellows base body (14) is closed off at one end by a pot bottom (16, 16', 16").
3. Pulsation damper element according to Claim 2, characterised in that the pot bottom (16, 16', 16") is designed as a carrier (16, 16') for a sealing element (9, 9') and/or as a sealing element (9", 16") of a fluid valve.
4. Pulsation damper element according to Claim 3, characterised in that the sealing element is designed as a sealing sphere (9) and/or as a sealing spherical cap (9') and/or as a sealing plate (9").
5. Pulsation damper element according to Claim 3 or 4, characterised in that the sealing element (9, 9') is fixedly or movably connected to the pot bottom (16, 16') designed as a carrier.
6. Pulsation damper element according to one of Claims 1 to 5, characterised in that, at the other end, the bellows base body (14) has a stable end region (12) which is usable, upon assembly of the pulsation damper element (3, 3', 3"), as an effective diameter (12.1) for a press-in operation and/or a caulking operation.
7. Pulsation damper element according to one of Claims 1 to 6, characterised in that the damper pot (10, 10', 10") is injection-moulded from plastic or formed from metal, preferably steel.
8. Pulsation damper element according to one of Claims 1 to 7, characterised in that the filling compound (20) is an elastic plastic, preferably an ethylene-propylene-diene monomer.
9. Fluid pump having a pulsation damper element (1) installed in the pump housing (3) and/or in a cover, characterised in that the pulsation damper element is designed according to one of Claims 1 to 8.
10. Fluid pump according to Claim 9, characterised in that the pulsation damper element (3, 3', 3") is designed as a return spring element of an outlet valve of the fluid pump (1).
11. Pulsation damper element for a fluid pump, substantially as hereinbefore described, with reference to the accompanying drawings.
12. Fluid pump substantially as hereinbefore described, with reference to the accompanying drawings.*::r: INTELLECTUAL . ... PROPERTY OFFICE Application No: GB 1110368.6 Examiner: James Paddock Claims searched: 1-12 Date of search: 17 October 2011 Patents Act 1977: Search Report under Section 17 Documents considered to be relevant: Category Relevant Identity of document and passage or figure of particular relevance to claims X 1,2,6,9 DE102008035943 Al CONTINENTAL See the figure, para 13 and WPI abstract accession No: 2009-F39151 [18]. Pulsation damper for pump outlet with bellows infilled with elastomer and absorption involving airspace 9.X 1-5 W000/11350 A CONTINENTAL See Figure 1 and WPI abstract accession No: 2000- 225424 [20]. Damper suitable for pump outlet with elastomer filler in interspaces between bellows corrugations. Note seal at base.A -U52002/100507 A BOSCH See the Figures. Moulded plastics check valve spring with interspaces.A -U52008/067805 A NISSAN See Figure 7. Pulsation absorber with spring element with spaces rubber filled.Categories: X Document indicating lack of novelty or inventive A Document indicating technological background and/or state step of the art.Y Document indicating lack of inventive step if P Document published on or after the declared priority date but combined with one or more other documents of before the filing date of this invention.same category.& Member of the same patent family E Patent document published on or after, hut with priority date earlier than, the filing date of this application.Field of Search:Search of GB, EP, WO & US patent docjments classified in the following areas of the UKCX Worldwide search of patent documents classified in the following areas of the IPC B6OT; FO4B; F16L The following online and other databases have been used in the preparation of this search report WPI, EPODOC, TXTE Intellectual Property Office is an operating name of the Patent Office www.ipo.gov.uk *.:r: INTELLECTUAL . ... PROPERTY OFFICE International Classification: Subclass Subgroup Valid From FO4B 0011/00 01/01/2006 B6OT 0008/40 01/01/2006 FO4B 0053/10 01/01/2006 Intellectual Property Office is an operating name of the Patent Office www.ipo.gov.uk