DE102010044427A1 - shaft seal - Google Patents

Abstract

The invention has for its object to develop a novel shaft seal, which reliably prevents standstill leakage and reduces leakage losses even with a rotating shaft, is easy to manufacture and assemble in terms of production technology, significantly reduces manufacturing costs and is at the same time "particle-insensitive", and also reduces wear and tear Components are minimized, in addition to the service life, reliability is significantly increased and even after a long period of use, an "air-free" vacuum filling is still possible. The shaft seal according to the invention with a seal housing (5), a running sleeve (6) and a rotationally symmetrical sealing membrane (7) made of an elastic material is characterized in particular by the fact that a radial centrifugal disc () on the running sleeve (6) towards the interior (1) 9) is arranged which projects beyond the inner cylinder (10) of the seal housing (5), and that a diaphragm contact plate (12) is arranged on the cylinder part (11) of the seal housing (5) towards the outer space (4) through its cylindrical inner opening (13) the barrel sleeve (6) protrudes towards the outer space (4), a working gap (14) being arranged between the inner opening (13) and the barrel sleeve (6), and on the one hand a radial sealing lip (2) at the two free ends of the sealing membrane (7) 17) and on the other hand an axial sealing lip (18) is arranged, the radial sealing lip (17) adjacent to the working gap (14) on the running sleeve (6), and the axial sealing lip (18) sealingly Bears against the centrifugal disc (9) on the housing side in such a way that an “arch spring” is formed between the radial sealing lip (17) and the axial sealing lip (18) by means of an elastic deformation of the sealing membrane (7). The invention relates to a shaft seal for sealing a rotating shaft which is led out of an interior space filled with a fluid medium, preferably with respect to the atmosphere.

Description

The invention relates to a shaft seal for sealing an outgoing from a filled with a fluid medium interior rotating shaft, preferably with respect to the atmosphere. Areas of application of such shaft seals are machine, apparatus and motor vehicle construction, such as, for example, the sealing of the drive shaft of a coolant pump.

In the prior art, the most diverse designs of shaft seals have become known. In the filed by the applicant DE 101 41 138 C2 is a radial shaft seal arranged with two spaced, to the shaft sealingly applied and obliquely against the pressure direction sealing lips prescribed, which is formed by two nested sealing membrane bodies, wherein between the two sealing membrane bodies, a support body is arranged, which is adjacent to the interior of the sealing membrane on their supports the side facing away from the inner chamber.

From the DE 10 2008 010 338 A and the DE 10 2008 010 341 A are also radial shaft seals for water pumps, with two spaced-apart sealing membrane body known, each having two sealingly applied to the shaft sealing lips. Characteristic of the two aforementioned types is that the two sealing membrane body are the same design and therefore can be manufactured in the same mold. Opposite the DE 10 2008 010 338 A rejects the DE 10 2008 010 341 A a collecting space for leakage fluid, in which a rotatably connected to the shaft to be sealed sling protrudes.

It is characteristic of all the above-mentioned designs that the sealing lips of the sealing membrane body which are disposed on a shaft or a shaft sleeve are most exposed to dirt load, and therefore also wear out first. The further outwardly disposed sealing lips of the second sealing membrane body should now seal the leak passing through the worn lips leakage in this case.

However, since the sealing lips of the second sealing membrane body run uncooled on the shaft, or the shaft sleeve, they are subject to increased wear and are hard. As a result, they lose their sealing force, which is absolutely necessary for preventing leaks, and can no longer completely fulfill their task as a seal after a certain period of use, so that the leakage losses increase significantly over the service life.

In cooling systems of motor vehicles, moreover, the first filling of the cooling system takes place, in that the cooling system is evacuated by means of a suction pump, tested for leaks, and then filled air-free with coolant using the generated negative pressure.

On the Erstbefüllung the previously described signs of wear on the sealing lips have no effect.

However, since many repair shops are already refilling with air under maintenance during maintenance or repair work, air can leak into the cooling circuit via leaking worn sealing lips.

Further disadvantages of the designs described in the prior art result, on the one hand, from the large number of individual components which make up the radial shaft seal described in the prior art, and, on the other, from the manufacturing accuracy resulting from their functional production and assembly and the costs associated with production and assembly. and also from a further problem of wear, as a result of which the rubber of the sealing lips "buries" in the "running area" of the shafts or shaft sleeves.

The object of the invention is now to develop a novel shaft seal for sealing an outgoing from a filled with a fluid medium interior rotating shaft against the atmosphere, which eliminates the aforementioned disadvantages of the prior art reliably avoids standstill leaks and even with a rotating shaft leakage losses lowers, while manufacturing technology is easy to manufacture and assemble, the production costs significantly reduced and at the same time "particle insensitive", also minimizes wear of the assemblies, and in addition to the life and reliability significantly increased, and even after prolonged use still an "air-free" vacuum filling allows.

According to the invention this object is achieved by a shaft seal according to the features of the main claim of the invention.

Advantageous embodiments, details and features of the invention will become apparent from the dependent claims and the following description of the embodiments of the invention in conjunction with the drawings for the solution according to the invention.

The invention will be explained in more detail with reference to two exemplary embodiments in conjunction with four figures.

It shows:

1 : the shaft seal according to the invention in the installed state after final assembly, ie after installation z. B. in a coolant pump;

2 : the shaft seal according to the invention during assembly;

3 : the shaft seal according to the invention in the delivery state after the final assembly, ie before installation, for. B. in a coolant pump;

4 : The shaft seal according to the invention in a further design in the installed state after final assembly.

In the 1 the shaft seal according to the invention is shown in the installed state after final assembly. This in 1 illustrated, shaft seal according to the invention serves to seal one of an interior filled with a fluid medium 1 a work enclosure 2 led out rotating shaft 3 opposite the outside space 4 ,

The shaft seal according to the invention consists of a seal housing 5 , which may be preferably formed as a deep-drawn part, a barrel sleeve 6 , which preferably consists of kolsterisiertem stainless steel, and a rotationally symmetrical sealing membrane 7 , which preferably consists of rubber, and one on the inner surface of the sealing membrane 7 arranged annular support body 8th , which is preferably brass.

The 2 shows the shaft seal according to the invention during assembly. The present inventive design is characterized in that on the barrel sleeve 6 to the interior 1 towards a radial centrifugal disc 9 is arranged, which the inner cylinder 10 of the seal housing 5 surmounted.

Characteristic is that on the cylinder part 11 of the seal housing 5 to the outside space 4 towards a diaphragm contact plate 12 is arranged through the cylindrical inner opening 13 the barrel sleeve 6 to the outside space 4 protrudes, being between the inner opening 13 and the barrel sleeve 6 a working gap 14 is arranged.

According to the invention in this context that on the cylinder part 11 of the seal housing 5 to the interior 1 towards a gasket 15 for a stationary seal 16 is arranged.

Essential to the invention is that at the two free ends of the sealing membrane 7 on the one hand a radial sealing lip 17 and on the other hand, an axial sealing lip 18 is arranged, wherein the radial sealing lip 17 the working gap 14 adjacent to the barrel sleeve 6 abuts and the Axialdichtlippe 18 Seal housing side of the centrifugal disc 9 is applied, wherein the sealing membrane 7 between the radial sealing lip 17 and the axial sealing lip 18 against the inner cylinder 10 of the working housing 2 and / or the diaphragm bearing plate 12 of the seal housing 5 by means of a supporting body 8th is tense.

According to the invention, the sealing membrane made of rubber, z. As FPM GFLT-S, or another rubber-like elastic material. It is also characteristic that during the assembly of the shaft seal the Axialdichtlippe 18 the sealing membrane 7 in the direction of the support body 8th shifted and the sealing membrane is biased such that during clamping / compression of the sealing membrane 7 by the elastic deformation of the sealing membrane 7 between that of the support body 8th to the inner cylinder 10 pressed area of the rubber-elastic sealing membrane 7 and the next to the Axialdichtlippe 18 on the inner cylinder 10 adjacent region of the sealing membrane 7 a vaulting spring 19 is trained.

In the 3 now the shaft seal according to the invention is shown in the delivery state after the final assembly.

For the delivery condition after final assembly, the axial closure of the cassette is characteristic.

For this purpose, the barrel sleeve 6 to the outside space 4 towards, in the prestressed state of the arch spring 19 , immediately next to the future work gap 14 According to the invention by widening (thorns of the open end) of the barrel sleeve with a bead 22 Mistake.

After the expansion according to the invention, ie after the generation of the bead 22 the shaft seal according to the invention is a prefabricated component in the form of a transportable cassette and can be easily transported and mounted. The flared end of the barrel later facilitates mounting on the pump shaft.

As part of the final assembly, the barrel sleeve 6 then only positioned in your final position, ie the working gap 14 Be "adjusted", so that in the 1 shown working state of the shaft seal according to the invention is produced.

Compared to the prior art, the solution presented here has a number of advantages.

On the one hand, this affects the interior 1 Centrifugal disc arranged on the medium side 9 As a centrifugal force filter and causes coarser dirt load, which in conventional shaft seals in the medium side arranged / n sealing lip / n penetrate and largely contribute to their wear, simply outward along the skirt wall of the centrifugal disc 9 thrown around the delivery volume flow taken, for example, transported to the filters, and to be deposited there.

At the same time, it acts between the centrifugal disc 9 and the seal housing 5 arranged annular gap as a gap filter, which also still in the lower speed range, the penetration of coarse dirt particles in the medium side Axialdichtlippe 18 in derogation.

This next to the slit filter on the centrifugal disc 9 adjacent Axialdichtlippe 18 primarily ensures tightness when the shaft is at a standstill or at low system pressures.

When vacuum filling the Axialdichtlippe 18 due to the arrangement according to the invention in this annular gap between the centrifugal disc 9 and the seal housing 5 drawn in, so that the inventive solution seals in vacuum filling of the vehicle cooling circuit as a valve.

The invention always biased buckle spring 19 ensures during the downtime or warm-up phases of the engine at the same time a Axialdichtlippenanpresskraft, which at standstill of the shaft 3 completely prevents the occurrence of leaks.

The axial sealing lip 18 However, it is not designed to handle the medium, eg. B. to retain coolant against higher pressure differences.

The dimensioning of the axial sealing geometry is inventively designed such that with increasing rotational speed of the shaft to build a hydrodynamic lubricating film between the Axialdichtlippe 18 and the slinger 9 comes, so that of the arching spring 19 to the centrifugal disc 9 Pressed axial sealing lip 18 on the centrifugal disc 9 floats, and in this operating state now the contact pressure of the buckling spring 19 always ensures an optimum sealing gap with minimal friction losses, so that when rotating shaft wear of the axial sealing lip 18 is largely prevented.

Due to the load-bearing lubricating film, the friction losses of the axial sealing lip are also reduced at the same time 18 to a minimum.

When rotating shaft so according to the invention the liquid medium, z. B. the coolant through the axial lubrication gap in the seal housing and fills the volume between the axial and radial sealing point.

As a result, the pressure equalization is made to the pump interior.

The radial sealing lip is now subjected to system pressure which supports the sealing function to the atmosphere.

The required pressure compensation is according to the invention additionally by the flexibility of the preferably made of rubber sealing membrane 7 further promoted, which can compensate for small pressure differences due to volume changes.

The radial sealing lip 17 then takes over the media seal with rotating shaft and higher system pressures.

By the aforementioned particle locks prevents laden with particles dirt load to the radial sealing lip 17 so that it is protected from direct exposure to wear-promoting particles and thus reaches a very long life.

Because the warming radial sealing lip 17 is always acted upon with a cooling medium forms with rotating sleeve 6 in the space between the radial sealing lip 17 and axial sealing lip 18 , the lubrication chamber 20 an internal cooling flow, which frictional heat from the radial sealing lip 17 to the centrifugal disc 9 transported.

The thin-walled metallic surface of the centrifugal disc 9 now allows the heat transfer to the cooler medium inside the pump.

This cooling of the sealing lips according to the invention causes wear of the sealing membrane 7 with the radial sealing lip 17 and the axial sealing lip 18 minimized and thereby significantly increases the life of the shaft seal according to the invention, so that a high reliability is always guaranteed even after prolonged use.

In special designs of the shaft seal according to the invention can already in the delivery state of the shaft seal after the final assembly, ie before installation, for. B. in a coolant pump, in the lubrication chamber 20 partially, or completely a lubricious medium, a lubricant 21 , for example, be arranged pure glycol.

This lubricant 21 additionally increases the service life of the sealing membrane 7 and thus also the radial sealing lip 17 and the axial sealing lip 18 because it "maintains" the lubricating lips made of rubber-elastic material continuously during cooling, and thereby avoids that hardens the rubber of the sealing lips and, for example, then "buries" and wears in the "running area" of the shafts or shaft sleeves.

The 4 now shows the shaft seal according to the invention in a further design in the installed state after final assembly.

According to the invention in this design on the support body 8th a compression spring web 23 arranged, and at the slinger 9 adjacent Axialdichtlippe 18 in the direction of the barrel sleeve 6 with a ring bridge 24 provided on the ring land 24 the axial sealing lip 18 one with a compression spring receptacle 25 Provided support sleeve 26 is applied.

Characteristic is still that between the compression spring 25 the support sleeve 26 and the compression spring web 23 a compression spring 27 is arranged, wherein in the area above the compression spring receptacle 25 on the rubber-elastic sealing membrane 7 one on the inner cylinder 10 fitting guide bead 28 is arranged.

In this embodiment of the solution according to the invention is that of the rubber-elastic sealing membrane 7 trained arch spring 19 according to the invention by a compression spring 27 supported, so that one in the design of the sealing membrane 7 , ie the selection z. As the wall thickness, the material composition, o. Ä., Not more of the spring characteristic of the buckle spring 19 depends, but that, depending on the respective existing boundary conditions, such as the media to be sealed, the temperature o. Ä., In the design of the sealing membrane 7 can decide freely, since the respectively required contact pressure of the axial sealing lip 18 to the centrifugal disc 9 by means of the compression spring used according to the invention 27 can be compensated ("reworked").

With all the designs of the solution according to the invention presented here, a novel shaft seal has been achieved for sealing a rotating shaft brought out of an interior filled with a fluid medium 3 To develop over the atmosphere, which eliminates the existing disadvantages of the prior art, reliably avoids standstill leaks, and rotates shaft leakage losses, manufacturing technology is easy to manufacture and assemble, the manufacturing cost significantly reduced, while "particle insensitive" is also the Wear of the assemblies minimized, and in addition to the lifetime and the reliability significantly increased, so that even after prolonged use even an "air-free" vacuum filling is possible.

LIST OF REFERENCE NUMBERS

1

inner space

2

labor housing

3

wave

4

outer space

5

seal housing

6

running sleeve

7

sealing membrane

8th

support body

9

slinger

10

inner cylinder

11

cylinder part

12

Membrane support plate

13

inner opening

14

working gap

15

seal Housing

16

stationary seal

17

Radial sealing lip

18

axial sealing lip

19

arching spring

20

lubrication chamber

21

lubricant

22

beaded

23

Spring bearing web

24

ring land

25

Pressure spring receiving

26

support sleeve

27

compression spring

28

guide bead

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10141138 C2 [0002]
• DE 102008010338 A [0003, 0003]
• DE 102008010341 A [0003, 0003]

Claims (8)

Shaft seal for sealing an interior space filled with a fluid medium ( 1 ) of a work enclosure ( 2 ) led out rotating shaft ( 3 ) in relation to the exterior space ( 4 ) with a seal housing ( 5 ) a barrel sleeve ( 6 ) and a rotationally symmetrical sealing membrane consisting of an elastic material ( 7 ) and one on the inner shell of the sealing membrane ( 7 ) arranged annular support body ( 8th ), characterized in that - on the barrel sleeve ( 6 ) to the interior ( 1 ) a radial centrifugal disc ( 9 ) is arranged, which the inner cylinder ( 10 ) of the seal housing ( 5 ) and that - on the cylinder part ( 11 ) of the seal housing ( 5 ) to the outside space ( 4 ) a Membrananlageplatte ( 12 ) is arranged through the inner cylindrical opening ( 13 ) the barrel sleeve ( 6 ) to the outside space ( 4 ), wherein between the inner opening ( 13 ) and the barrel sleeve ( 6 ) a working gap ( 14 ), and that - on the cylinder part ( 11 ) of the seal housing ( 5 ) a seal receiver ( 15 ) for a stationary seal ( 16 ), and that - at the two free ends of the sealing membrane ( 7 ) on the one hand a radial sealing lip ( 17 ) and on the other hand an axial sealing lip ( 18 ), wherein the radial sealing lip ( 17 ) the working gap ( 14 ) adjacent to the barrel sleeve ( 6 ) and the axial sealing lip ( 18 ) on the sealing housing side on the centrifugal disk ( 9 ), and the sealing membrane ( 7 ) between the radial sealing lip ( 17 ) and the axial sealing lip ( 18 ) against the inner cylinder ( 10 ) of the working housing ( 2 ) and / or the membrane attachment plate ( 12 ) of the seal housing ( 5 ) by means of a supporting body ( 8th ), wherein - the axial sealing lip ( 18 ) of the sealing membrane ( 7 ) in the direction of the support body ( 8th ) and thus the sealing membrane ( 7 ) is biased so that - between the support body ( 8th ) to the inner cylinder ( 10 ) pressed-on region of the sealing membrane ( 7 ), and in addition to the Axialdichtlippe ( 18 ) on the inner cylinder ( 10 ) adjacent region of the sealing membrane ( 7 ), when biased by the elastic deformation of the sealing membrane ( 7 ) a "curvature feather" ( 19 ) is formed. Shaft seal according to claim 1, characterized in that the sealing membrane ( 7 ) consists of rubber. Shaft seal according to claim 1, characterized in that in the free space of the shaft seal between the sealing membrane ( 7 ), the barrel sleeve ( 6 ) and the centrifugal disc ( 9 ) a lubrication chamber ( 20 ) is arranged. Shaft seal according to claim 3, characterized in that in the lubrication chamber ( 20 ) a lubricant ( 21 ) is arranged. Shaft seal according to claim 4, characterized in that the lubricant ( 21 ) Glycol is. Shaft seal according to claim 1, characterized in that the on the barrel sleeve ( 6 ) adjacent radial sealing lip ( 17 ) in the direction of the centrifugal disc ( 9 ), and / or on the centrifugal disc ( 9 ) adjacent Axialdichtlippe ( 18 ) in the direction of the barrel sleeve ( 6 ) is angled. Shaft seal according to claim 1, characterized in that the barrel sleeve ( 6 ) to the outside space ( 4 ), in the prestressed state of the curvature spring ( 19 ), next to the future work gap ( 14 ) with a bead ( 22 ) is provided. Shaft seal according to claim 1, characterized in that - on the supporting body ( 8th ) a pressure spring contact bar ( 23 ), and - on the centrifugal disc ( 9 ) adjacent Axialdichtlippe ( 18 ) in the direction of the barrel sleeve ( 6 ) with a ring land ( 24 ), wherein - at the ring land ( 24 ) of the axial sealing lip ( 18 ) one with a compression spring receptacle ( 25 ) provided support sleeve ( 26 ), and - between the compression spring receptacle ( 25 ) of the support sleeve ( 26 ) and the compression spring web ( 23 ) a compression spring ( 27 ), wherein - in the region at the sealing membrane ( 7 ) above the compression spring receptacle ( 25 ) one on the inner cylinder ( 10 ) adjoining guide bead ( 28 ) is arranged.

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