WO2010145633A2

WO2010145633A2 - Vacuum pump

Info

Publication number: WO2010145633A2
Application number: PCT/DE2010/000620
Authority: WO
Inventors: Christoph Heidemeyer; Alexander Freiburg; Ralf Friedmann; Daniel Müller
Original assignee: Ixetic Hückeswagen Gmbh
Priority date: 2009-06-17
Filing date: 2010-06-02
Publication date: 2010-12-23
Also published as: WO2010145633A3; DE112010002592A5

Abstract

The invention relates to a vacuum pump comprising a pressure chamber in which excess pressure is produced when the vacuum pump is in operation, said excess pressure being reduced by a discharge valve. The invention is characterised in that at least one metal part of the discharge valve comprises at least one plastic layer for improving the sealing and/or damping properties.

Description

vacuum pump

The invention relates to a vacuum pump with a pressure chamber in which an overpressure is generated during operation of the vacuum pump, which is degradable via an outlet valve.

The vacuum pump is preferably designed as a vane pump, as disclosed, for example, in International Publication WO 2004/074687 A2. Vacuum pumps are used in motor vehicles, for example, to generate a vacuum in a brake booster.

The object of the invention is to reduce unwanted noise during operation of a vacuum pump with a pressure chamber in which an overpressure is generated during operation of the vacuum pump, which is degradable via an outlet valve.

The object is achieved in a vacuum pump with a pressure chamber in which during operation of the vacuum pump, an overpressure is degradable via an outlet valve, achieved in that at least one metal part of the exhaust valve to improve the sealing and / or damping properties has at least one plastic layer , The metal part is preferably a sheet metal part, in particular a valve spring or a valve holder. The plastic layer is preferably formed of an elastomeric plastic material and is also referred to as a rubber layer. By applying the plastic layer to a contact surface of the metal part, the tightness of the outlet valve can be increased if the plastic-coated contact surface sealingly abuts a mating surface. Alternatively or additionally, the or an additional plastic layer may be provided in the interior of the metal part in order to improve the damping properties, without the plastic layer being worn out by coming into contact with other metal parts. By the plastic layer unwanted noise, which are generated by a vibration excitation of the metal part in the operation of the vacuum pump can be attenuated.

A preferred embodiment of the vacuum pump is characterized in that the metal part is a valve spring, which closes in a closed state, at least one outlet opening, from which it lifts off when opened. The opening of the valve spring is caused by the pressure in the pressure chamber of the vacuum pump. By contacting the valve spring with a housing region of the vacuum pump delimiting the outlet opening when closing the outlet valve, undesired impact noises can be caused during operation, which are significantly reduced by the plastic layer.

A further preferred embodiment of the vacuum pump is characterized in that the valve spring is provided on its side facing the outlet opening with a plastic layer. As a result, unwanted impact noise when closing the valve spring can be significantly reduced. In addition, the sealing effect is improved in the closed state of the valve spring.

A further preferred embodiment of the vacuum pump is characterized in that the valve spring is provided on its side facing away from the outlet opening with a plastic layer. As a result, the internal damping of the valve spring can be significantly increased and impact noises on a valve holder can be reduced.

A further preferred embodiment of the vacuum pump is characterized in that the valve spring comprises at least one metal layer. The metal layer is preferably formed from sheet metal and may be provided on one or both sides with a plastic layer. The valve spring may also comprise a plurality of metal layers of the same material or different materials.

A further preferred embodiment of the vacuum pump is characterized in that the metal layer has a thickness of slightly less than one millimeter. For example, the metal layer has a thickness of 0.2 millimeters with a tolerance of plus / minus 0.015 millimeters.

A further preferred embodiment of the vacuum pump is characterized in that the metal layer is formed from spring steel sheet. The spring steel sheet is provided according to an essential aspect of the invention on one side or on both sides with a plastic layer.

A further preferred embodiment of the vacuum pump is characterized in that the valve spring is designed as a flat shape spring. The flat form spring lies in the built condition on the outlet port of the vacuum pump. Depending on the pressure in the pressure chamber of the vacuum pump, the flat-form spring lifts off from the outlet opening, so that the overpressure in the pressure chamber of the vacuum pump is reduced via the opened outlet opening.

A further preferred embodiment of the vacuum pump is characterized in that the valve spring comprises two metal layers, between which a plastic layer is arranged. This arrangement has the advantage that the plastic layer does not come into contact with other metal parts during operation of the vacuum pump. This prevents unwanted wear of the plastic layer.

A further preferred embodiment of the vacuum pump is characterized in that the plastic layer of the valve spring has a thickness of 25 to 50 micrometers. This thickness has been found to be particularly advantageous in experiments carried out in the context of the present invention.

A further preferred embodiment of the vacuum pump is characterized in that the metal part is a valve holder which limits the opening movement of the valve spring or a valve spring. The valve holder is preferably formed of sheet metal and, for example by means of a screw, attached to the vacuum pump in the region of the outlet opening. In this case, the valve holder is preferably angled away from the outlet opening such that the valve spring strikes against the valve holder when it is opened. This prevents the valve spring from undergoing excessive deflection when it is opened.

A further preferred embodiment of the vacuum pump is characterized in that the valve holder is provided on its valve spring side facing side with a plastic layer. As a result, unwanted impact noise or rattling noises when striking the valve spring on the valve holder are significantly reduced.

A further preferred embodiment of the vacuum pump is characterized in that the valve holder is provided on its side facing away from the valve spring with a plastic layer. This arrangement has the advantage that the plastic layer does not wear out by coming into contact with the valve spring. By this arrangement, the internal damping of the valve holder can be significantly increased. The valve holder can also be provided on both sides with the plastic layer. - A -

A further preferred embodiment of the vacuum pump is characterized in that the valve holder comprises at least one metal layer. The metal layer is preferably formed from sheet metal and coated on at least one side with plastic.

A further preferred embodiment of the vacuum pump is characterized in that the metal layer has a thickness of 0.4 to 1, 25 millimeters. This thickness has been found to be particularly advantageous in experiments carried out in the context of the present invention.

A further preferred embodiment of the vacuum pump is characterized in that the metal layer is formed from sheet steel. The valve holder, as well as the valve spring, preferably designed as a stamped part.

Another preferred embodiment of the vacuum pump is characterized in that the metal layer is formed of a stainless stainless steel. The shape of the valve holder is preferably adapted to the shape of the valve spring.

A further preferred embodiment of the vacuum pump is characterized in that the valve holder comprises two metal layers, between which a plastic layer is arranged. This arrangement has the advantage that the plastic layer is protected inside the valve holder and is exposed to less wear.

A further preferred embodiment of the vacuum pump is characterized in that the plastic layer of the valve holder has a thickness of 25 to 50 micrometers. This thickness has been found to be particularly advantageous in experiments carried out in the context of the present invention.

A further preferred embodiment of the vacuum pump is characterized in that the plastic layer is formed from an elastomeric plastic material. This is preferably a rubber-like plastic material, which is also referred to as rubber.

Further advantages, features and details of the invention will become apparent from the following description in which, with reference to the drawings, various embodiments are described in detail. Show it: Figure 1 is a vacuum pump in the open state without a lid in front view;

FIG. 2 shows the vacuum pump from FIG. 1 in the rear view;

Figure 3 is a sectional view taken along the line HI-III in Figure 2;

Figure 4 is a sectional view taken along the line IV-IV in Figure 2;

Figure 5 is an enlarged detail V of Figure 4;

Figure 6 is a valve spring of the vacuum pump of Figures 1 to 5 in plan view and

Figure 7 shows the valve spring of Figure 6 in front view.

In Figures 1 to 5, a vacuum pump 1 is shown in various views and sections. The vacuum pump 1 comprises a housing 2 with a housing pot 4 and a cover 5. Outside the housing pot 4, an inlet nozzle 6 is provided, via which a working medium, such as air, is sucked into a working space 8 in the interior of the housing 2, when the vacuum pump 1 is driven.

The working space 8 is limited in the radial direction by a circulation contour 10, which is also referred to as a stroke contour. In the axial direction, ie in the direction or parallel to a rotation axis 11 of the vacuum pump 1, the working space 8 is bounded by the bottom of the housing pot 4 and the lid 5. In the working space 8, a wing 12 is driven by a rotor 14. The wing 12 is guided in a wing receiving slot of the rotor 14 within the circulation contour 10 slidably. At the ends of the wing 12 caps are attached, which abut the circulation contour 10. The rotor 14 hugs with its outer contour in a Schmiegespalt 16 to the circulation contour 10th

By the rotor 14 and the wing 12 of the working chamber 8 of the vacuum pump 1 in the housing 2 in dependence on the direction of rotation and the angle of rotation of the rotor 14 in a suction chamber 18 and a pressure chamber 20 is divided. The suction chamber 18 is also referred to as a suction chamber. Analogously, the pressure chamber 20 is also referred to as a pressure chamber. The suction space 18 communicates with the inlet port 6 of the vacuum pump 1 in conjunction. About the input port 6, the working fluid, in particular air, sucked into the suction chamber 18 and mixed with lubricant, in particular with oil, to form an air-lubricant mixture and pressurized in the pressure chamber 20. In a preferred application, the vacuum pump 1, which is also referred to as a monoflügelzellenpumpe because of its one wing 12, used to create a negative pressure, that is, a vacuum, to a brake booster of a motor vehicle.

The working space 8 in the interior of the vacuum pump 1 is connected via two outlet openings 21, 22 with the environment of the vacuum pump 1, in particular with a crankcase of an internal combustion engine of the motor vehicle, in connection. The outlet opening 21 connects the pressure space 20 with the surroundings of the vacuum pump 1. The outlet opening 22 connects the suction space 18 with the environment of the vacuum pump 1. The second outlet opening 22 allows a pressure reduction when the rotor 14 rotates with the wing 12 against its normal operating direction of rotation , This prevents undesired damage to the vacuum pump 1. The normal direction of rotation of the vacuum pump 1 is indicated in Figure 2 by an arrow 24.

The two outlet openings 21, 22 are closed by an outlet valve 25, which comprises a valve holder 28 which is fastened by means of a screw 30 between the two outlet openings 21 and 22 at the bottom of the housing pot 4. Between the bottom of the housing pot 4 and the valve holder 28, a valve spring 35 is arranged. The valve spring 35 is designed as a flat-form spring and closes in its closed position the two outlet openings 21, 22. At an overpressure in the working chamber 8, the valve spring 35 lifts off from the corresponding outlet opening 21, 22 to allow a pressure reduction in the environment of the vacuum pump 1 , In Figures 3 and 5 it can be seen that the valve holder 28 is angled at an angle of about ten degrees of the valve spring 35. By the valve holder 28, the movement of the valve spring 35 is limited when opening.

In Figure 5 it can be seen that the valve holder 28 comprises two metal layers 41 and 42, between which a plastic layer 45 is arranged. The two metal layers 41, 42 are preferably formed from sheet steel. The plastic layer 45 is preferably formed from an elastomeric plastic material. The plastic layer 45 can significantly reduce noise caused by impact of the valve spring 35 on the valve holder 28. Alternatively or additionally, the or an additional plastic layer on the valve spring 35 facing and / or facing away from the valve holder 28 may be provided.

The two metal layers 41 and 42 preferably each have a thickness of 0.4 to 1, 25 millimeters. The plastic layer 45 preferably has a thickness of 25 to 50 micrometers. The sandwich material with the plastic layer 45 arranged between the two metal layers 41, 42 has proved to be particularly advantageous with regard to the damping of vibrations excited by the valve spring 35.

In Figures 6 and 7, the valve spring 35 is shown in two different views. In the plan view of Figure 6 it can be seen that the valve spring 35 has substantially the shape of a circular arc. In the center of the circular arc 60, the valve spring 35 has a through hole 62 which serves to fasten the valve spring 35 together with the valve holder 28 by means of the screw 30 at the bottom of the housing pot 4.

In the front view shown in Figure 7 it can be seen that the valve spring 35 comprises two metal layers 71, 72, which are preferably formed from spring steel sheet. Between the two metal layers 71, 72, a plastic layer 75 is disposed of an elastomeric plastic material. By the plastic layer 75 unwanted noise when opening and closing the valve spring 35 can be significantly reduced. The arrangement of the plastic layer 75 between the two metal layers 71, 72, moreover, an undesirable wear of the plastic layer 75 can be prevented.

Alternatively, it is possible to provide the valve spring 35 externally with at least one or an additional plastic layer. By a plastic layer on the outlet openings 21, 22 facing side of the valve spring 35, the sealing of the outlet openings 21, 22 can be improved in the closed state of the valve spring 35. By an additional plastic layer on the valve holder 28 side facing the valve spring 35 undesirable impact noise when striking the valve spring 35 can be reduced to the valve holder 28. Bezugszeichenlistβ

vacuum pump

casing

housing pot

cover

inlet connection

working space

peripheral contour

axis of rotation

wing

rotor

Schmiegespalt

suction

pressure chamber

outlet

arrow

outlet valve

valve holder

screw

valve spring

metal layer

Plastic layer

arc

Through Hole

metal layer

Plastic layer

Claims

claims

1. Vacuum pump with a pressure chamber (20), in which during operation of the vacuum pump, an overpressure is generated, which is degradable via an outlet valve (25), characterized in that at least one metal part of the exhaust valve (25) to improve the sealing and / or damping properties at least one plastic layer (45, 75).

2. Vacuum pump according to claim 1, characterized in that the metal part is a valve spring (35), the at least one outlet opening (21, 2) closes in a closed state, from which it lifts off when opened.

3. Vacuum pump according to claim 2, characterized in that the valve spring (35) on its outlet opening (21, 22) facing side is provided with a plastic layer.

4. Vacuum pump according to claim 2 or 3, characterized in that the valve spring (35) on its outlet opening (21, 22) facing away from the side is provided with a plastic layer.

5. Vacuum pump according to one of claims 2 to 4, characterized in that the valve spring (35) comprises at least one metal layer (71, 72).

6. Vacuum pump according to claim 5, characterized in that the metal layer (71, 72) has a thickness of slightly less than one millimeter.

7. Vacuum pump according to claim 5 or 6, characterized in that the metal layer (71, 72) is formed from spring steel sheet.

8. Vacuum pump according to one of claims 2 to 7, characterized in that the valve spring (35) is designed as a flat shape spring.

9. Vacuum pump according to one of claims 2 to 8, characterized in that the valve spring (35) comprises two metal layers (71, 72), between which a plastic layer (75) is arranged.

10. Vacuum pump according to one of claims 2 to 9, characterized in that the plastic layer (75) of the valve spring (35) has a thickness of 25 to 50 micrometers.

11. Vacuum pump according to one of the preceding claims, characterized in that the metal part is a valve holder (28) which limits the opening movement of one or the valve spring (35).

12. Vacuum pump according to claim 11, characterized in that the valve holder (28) is provided on its valve spring (35) facing side with a plastic layer.

13. Vacuum pump according to claim 11 or 12, characterized in that the valve holder (28) on its valve spring (35) facing away from the side is provided with a plastic layer.

14. Vacuum pump according to one of claims 11 to 13, characterized in that the valve holder (28) comprises at least one metal layer (41, 42).

15. Vacuum pump according to claim 14, characterized in that the metal layer (41, 42) has a thickness of 0.4 to 1, 25 millimeters.

16. Vacuum pump according to claim 14 or 15, characterized in that the metal layer (41, 42) is formed from sheet steel.

17. Vacuum pump according to claim 14 or 15, characterized in that the metal layer (41, 42) is formed from a stainless stainless steel.

18. Vacuum pump according to one of claims 11 to 17, characterized in that the valve holder (28) comprises two metal layers (41, 42), between which a plastic layer (45) is arranged.

19. Vacuum pump according to one of claims 11 to 18, characterized in that the plastic layer (45) of the valve holder (28) has a thickness of 25 to 50 micrometers.

20. Vacuum pump according to one of the preceding claims, characterized in that the plastic layer (45,75) is formed of an elastomeric plastic material.