WO2008089910A1

WO2008089910A1 - Valve device for a low-pressure supply system

Info

Publication number: WO2008089910A1
Application number: PCT/EP2008/000329
Authority: WO
Inventors: Mirko Kupceric
Original assignee: Ixetic Hückeswagen Gmbh
Priority date: 2007-01-27
Filing date: 2008-01-17
Publication date: 2008-07-31
Also published as: DE112008000064A5; EP2126428A1

Abstract

The invention relates to a valve device for a low-pressure supply system with a membrane unit (9) releasing a flow path in one direction only. The membrane unit comprises at least two membrane elements (9a, 9b), wherein at least one thereof deforms during operation of the low pressure supply-system so that the membrane elements come in contact with each other and the oscillations of the membrane unit are damped.

Description

Valve device for a vacuum supply system

description

The invention relates to a valve device for a vacuum supply system according to the preamble of claim 1.

Valve devices of the type discussed here are known. They are used for example in pneumatic systems for vacuum supply for braking systems of motor vehicles. In certain operating points of the system, natural oscillations of a membrane unit of the valve device may occur, which, if they are within the audible range, in many cases lead to disturbances and irritations. Attempts have already been made to avoid vibrations of this kind by the fact that the rigidity of a membrane element of the membrane unit was changed so that resonance frequencies could not occur in the regular operation of the pneumatic system. In such cases, however, it was necessary to specifically select the characteristics of the membrane unit for different pneumatic systems so that resonance frequencies were avoided. This is expensive and therefore expensive.

The object of the invention is therefore to provide a valve device which is simple in construction and generally usable.

To solve this problem, a valve device is proposed which comprises the features mentioned in claim 1. The valve device is provided for a vacuum system, for example of a motor vehicle, for example for a brake booster. It has a membrane unit which releases a flow path in one direction only, namely a connection of one Consumer, which is to be acted upon by negative pressure, to a vacuum source, such as a vacuum pump. The valve device is characterized in that the membrane unit has at least two membrane elements, of which at least one deforms during operation of the vacuum supply system, so that the membrane elements touch each other. As a result, frictional forces are built up which damp vibrations of the membrane unit.

Preferred is an embodiment of the valve device, which is characterized in that the membrane elements have different stiffnesses. This embodiment avoids that the membrane elements have the same resonant frequencies and can quasi mutually sway.

In a further preferred embodiment it is provided that the membrane elements show different shapes. This embodiment also serves to avoid the same resonance frequencies and thus to have the possibility of avoiding vibrations due to frictional forces.

In a further preferred embodiment, the membrane elements have different masses in order to achieve optimum damping properties.

In a further preferred embodiment, it is provided that the membrane elements have different mass distributions, which also serve to avoid vibrations.

In addition, an embodiment of the valve unit is preferred, which is characterized in that at least one of Membrane elements has a gain which serves to shift the resonant frequency of the associated membrane element and thus to improve the damping.

In a further preferred embodiment, it is provided that at least one of the membrane elements has a weakening range which influences the resonance frequency of the membrane element in order to avoid that both membrane elements have the same resonance frequency.

In a further preferred embodiment it is provided that the one membrane element is mushroom-shaped, while the other is realized as a disc with a recess into which a region of the first membrane element is insertable.

Particularly preferred is an embodiment of the valve device, which is characterized in that the membrane elements are integrally formed.

Furthermore, an embodiment of the valve device is preferred, which is characterized in that in the contact region of the two membrane elements differently shaped contact areas are provided. These can be adapted to the vibration properties of the membrane elements in such a way that an optimal damping behavior results.

Further embodiments emerge from the subclaims.

The invention will be explained in more detail below with reference to the drawing. The single FIGURE shows a longitudinal section through a valve device. The valve device 1 is used in particular with a vacuum supply system, for example an internal combustion engine, for example with a brake booster. The valve device 1 is connected to a vacuum source, for example a vacuum pump, of the vacuum supply system and supplies the load, in this case, for example, the brake booster, with negative pressure. During operation of the supply system, a medium, for example air, is sucked in via the suction side 3 of the valve device, which faces the consumer, and via

10 passed a negative pressure side 5 to the vacuum source. Inside the valve device 1, a receiving space 7 is formed which receives a membrane unit 9. This is arranged in the fluid path between the suction side 3 and the low-pressure side 5, so that in the figure, a bottom-up directed media

15 ström results, which is indicated by the arrows 11 and 13. The membrane unit 9 is designed so that the flow path is released in a flow from bottom to top and that in an opposite flow it is interrupted.

The valve device has a housing 15 with a substantially

20 chen cup-shaped lower part 17 and a lid 19 which is lockingly inserted into the lower part 17 and the membrane unit 9 holds so that it rests on a sealing surface 21 in the lower part 17.

The membrane unit 9 is supplied with a medium from below via at least one feed opening 23 provided in the lower part 17 when the underprint supply system is active. For this purpose, a negative pressure is built up above the membrane unit 9 and a medium is sucked off via the at least one supply opening 23 via at least one suction opening 25. Due to the negative pressure in the At least one suction opening 25, a negative pressure in the receiving space 7 is constructed, so that the membrane unit 9 lifts by the pressure in the at least one feed opening 23. The given inside the valve device 1 flow is indicated by arrows, it being noted here that in the illustrated in the figure functional position of the membrane unit 9, the flow path between the consumer and the vacuum supply system is interrupted. This is, according to the explanations set out here, opened by the fact that at a negative pressure in the at least one suction opening 25, the membrane unit at least partially lifted from the sealing surface 21, so that a media flow through the supply opening 23 through the receiving space 7 and the suction opening 25 may arise ,

From the illustration according to FIG. 1, it is clear that the membrane unit 9 is constructed in several parts and has at least two membrane elements 9a and 9b. It is also conceivable, however, to provide more than two such membrane elements.

The one, here upper, membrane element 9a is pressed by the cover 19 together with the underlying membrane element 9b against an abutment 27, which is part of the lower part 17 here. Preferably, the lower part 7 is formed so that its bottom has the abutment 27 and at least one bore which forms the at least one feed opening 23. Preferably, a plurality of holes lying on an imaginary circle or supply openings 23 are provided, wherein a central axis 29 of the valve device 1 extends through the center of the imaginary circle. The distribution of the supply channels, their size, contour and distance to the center axis 29 can be adapted to different applications, so that the forces exerted by the medium flow on the underside of the membrane unit 9 can be adapted to different application cases.

The upper membrane element 9a is, as the figure shows, preferably mushroom-shaped and extends through the preferably disc-shaped

, J-shaped lower membrane element 9b in a central

Opening 31 with an extension 33, which in a recess 35 in

10 lower part 17 engages, which is arranged in the region of the abutment 27.

The longitudinal section through the valve device 1 shows that the upper membrane element 9a has an upwardly curved, umbrella-like region which, with its outer edge, rests on the outer rim.

15 rich of the disc-shaped lower membrane element 9b rests, so that a contact region 37 is formed. To a defined

Arrangement of the outer edge of the upper membrane element 9a on the

To ensure top of the lower membrane element 9b, the upper membrane element on its underside a recess

20 39 have.

In the embodiment shown in the figure, the upper membrane element 9a seen in plan view may be circular, as well as the lower membrane element 9b. In this case, the two membrane elements 9a and 9b have the same size, 25 so that at the outer edge of the membrane unit 9, the contact area 37 results, which is here then annular. The membrane elements 9a and 9b of the membrane unit 9 can have different stiffnesses. It is thereby achieved that, when a medium flow is established by the valve device 1, vibrations in the membrane unit 9, in this case in the membrane elements 9a and 9b, may be excited, but that these have different resonance frequencies. This ensures that frictional forces are built up in the contact area 37 which dampen vibrations.

In the embodiment shown in the figure, the upper membrane element 9a rests on the lower membrane element 9b. It is also conceivable, however, for the outer edge of the upper membrane element 9a to be located at a distance from the outer edge of the lower membrane element 9b, as long as there is no flow through the valve element 1. If this is built up by a negative pressure on the negative pressure side 5 of the valve device 1, the lower membrane element 9b bends upward and, at least in this operating state, comes into contact with the upper membrane element 9a, so that the contact region 37 is formed and frictional forces occur.

The membrane elements 9a and 9b can have different shapes to ensure adaptation to different resonance frequencies. For example, the lower membrane element 9b may be formed star-shaped, and thereby only touch the areas of the sealing surface 21, in which the at least one supply opening 23 is provided. The upper membrane element 9a can be round, but also likewise star-shaped, in order to cover the different regions or arms of the star-shaped element. Touch membrane element 9b and attenuate vibrations there.

The shapes of the membrane elements 9a and 9b can be varied not only in plan view but also in cross section. The upper membrane element 9a can thus also be designed as a flat disc with a recess 39 which contacts the lower membrane element 9b. It is therefore not absolutely necessary to provide the (_) upper membrane element 9a with an upper curvature and thus to make it mushroom-shaped.

In order to influence the vibration characteristics of the membrane elements 9a and 9b of the membrane unit 9, the membrane elements 9a, 9b can also have different masses or different mass distributions. The thickness of the membrane elements 9a and 9b can thus vary from the inside to the outside. Also, internal

15 half of a membrane element 9a and / or 9b different materials are combined with each other to realize different masses and / or mass distributions or stiffnesses to realize.

In order to vary the vibration characteristics of the membrane elements 9a and 20b, in at least one of these reinforcements or weakening regions may be provided.

In the explanation of the membrane elements 9a and 9b, it was assumed that the membrane elements 9a and 9b touch each other in their outer edge region, so that an annular contact area 37 results. By the choice or design of the mutually facing surfaces of the membrane elements 9a and 9b, the size and / or the shape of the contact In this case, it is also possible to vary the shape and / or size of the contact regions as a function of the negative pressure and / or the flow velocity of the medium flowing through the valve device 1.

Incidentally, it is also possible to form the contact regions between the two membrane elements 9a and 9b not only annularly or ring-segment-shaped. It is also conceivable for the membrane elements to touch each other in the region of more or less radially extending contact regions, wherein radial alignment with respect to the central axis 29 is meant.

Such a variation of size and shape of the contact regions is also possible depending on the fluid flow incident on the membrane unit 9, in particular in that the shape, size and / or arrangement of the at least one supply opening 23 is varied.

Another possibility for influencing the frictional forces in the at least one contact region 37 is to vary the surface structure of the mutually facing surfaces of the membrane elements 9a and 9b. The surfaces may be roughened, having burls, grooves or corrugations, slots or the like in order to vary the frictional forces and damping properties over a wide range.

An influencing of the frictional forces between the membrane elements 9a and 9b can also take place in that they intermesh at least in certain regions. In the fields, in where the membranes 9a, 9b interlock more or less, frictional forces are built up, which can be influenced by the type of entanglement and the size of the hooking areas.

The figure shows a preferred embodiment of the membrane 5 unit 9: This is formed in two parts and thus comprises a separate upper membrane element 9a and a separate lower membrane element 9b.

However, it is very well conceivable to form the two membrane elements 9a and 9b in one piece, so that they are integrally formed, for example, in their central region, ie in the region of the central axis 29, and are implemented at a distance therefrom, ie separated from the outside.

From the longitudinal section through the valve unit 1 shown in the figure, it can be seen that the lower boundary surface of the lid

15 19, which faces the membrane unit 9, is not flat, that is located in a plane on which the central axis 29 perpendicular

^ stands. It is therefore very conceivable that the outer edge of the lower region of the lid 19 springs back against an inner region which rests in the middle on the membrane unit 9. The

20 lower boundary surface may be bulging in the direction of the membrane unit 9. If, therefore, the valve device 1 flows through a flow in accordance with the arrows 11 and 13 from bottom to top, the membrane unit 9, in particular the membrane element 9a, can deform and move upward in the direction of

25 the lid 19 are deformed, wherein the outer edge of the membrane unit 9 and the membrane element 9a can be bent further upwards than the central region of the membrane Incidentally, it may be provided that the membrane unit 9 also serves as a limiting element: If the membrane unit 9 is deflected so far upwards that it bears against the lower boundary wall of the lid 19, then the membrane unit 9 closes the at least one suction opening 25 in the cover 19, so that the running through the valve device 1 flow is interrupted. Thus, the valve device 1 can also assume a safety function, which ensures that the extracted from the consumer media flow is not too strong.

In such an embodiment of the valve device 1 whose check valve function is maintained.

LIST OF REFERENCE NUMBERS

1 valve device

3 suction side

5 negative pressure side

7 recording room

9 membrane unit θa upper membrane element

9b lower membrane element 1 media flow, arrow 3 media flow, arrow 5 housing 7 lower part 9 cover 1 sealing surface 3 supply opening 5 suction opening 7 abutment 9 center axis 1 central opening 3 extension 5 recess 7 contact areas 9 recess

Claims

claims

1. Valve device for a negative pressure supply system with a flow path in one direction only releasing membrane unit (9), characterized in that the membrane 5 unit (9) at least two membrane elements (9a, 9b), of which at least one in Operation of the vacuum f ") supply system deformed, so that the membrane elements

(9a, 9b) and the vibrations of the membrane unit (9) are damped.

2. Valve device according to claim 1, characterized in that the membrane elements (9a, 9b) have different stiffnesses.

3. Valve device according to claim 1 or 2, characterized in that the membrane elements (9 a, 9 b) have different shapes 15.

4. Valve device according to one of the preceding claims, characterized in that the membrane elements (9a, 9b) have different masses.

5. Valve device according to one of the preceding claims, characterized in that the membrane elements (9a, 9b) have different mass distributions.

6. Valve device according to one of the preceding claims, characterized in that at least one of the membrane elements (9a, 9b) has a reinforcement.

7. Valve device according to one of the preceding claims, characterized in that at least one of the membrane elements (9a, θb) has a weakening region.

8. Valve device according to one of the preceding claims, 5 characterized in that the membrane elements at least partially intermesh.

^") 9. Valve device according to one of the preceding claims, characterized in that at least one of the membrane elements is mushroom-shaped.

10. Valve device according to one of the preceding claims, characterized in that at least one of the membrane elements is disc-shaped.

11. Valve device according to claim 10, characterized in that the disk-shaped membrane element a - vorzugswei-

15 se central - recess into which an area of the other membrane element is insertable.

12. Valve device according to one of the preceding claims, characterized in that the membrane elements (9a, 9b) are integrally formed.

20 13. Valve device according to one of the preceding claims, characterized in that in the contact region of the two membrane elements (9 a, 9 b) are provided differently shaped contact surfaces.

14. Valve device according to one of the preceding claims, characterized in that contact surfaces of different sizes are provided in the contact area.

15. Valve device according to one of the preceding claims, 5 characterized in that the shape and / or the size of the contact surfaces in dependence on the negative pressure and / or the flow velocity of the valve device (1) through j flowing medium changes.

16. Valve device according to one of the preceding claims, 10, characterized in that the arrangement of the contact surfaces and / or their size and / or their shape in dependence on the on the membrane unit (9) impinging fluid flow is / is selected.

17. Valve device according to one of the preceding claims, 15 characterized in that the contacting surfaces of the membrane elements (9a, 9b) have the same or complementary structures.