GB2353336A - Seal assembly for a rod - Google Patents
Seal assembly for a rod Download PDFInfo
- Publication number
- GB2353336A GB2353336A GB0020205A GB0020205A GB2353336A GB 2353336 A GB2353336 A GB 2353336A GB 0020205 A GB0020205 A GB 0020205A GB 0020205 A GB0020205 A GB 0020205A GB 2353336 A GB2353336 A GB 2353336A
- Authority
- GB
- United Kingdom
- Prior art keywords
- sealing
- rod
- sealing assembly
- sealing element
- assembly according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 238000007789 sealing Methods 0.000 claims abstract description 75
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims abstract description 13
- 239000004810 polytetrafluoroethylene Substances 0.000 claims abstract description 13
- 239000000314 lubricant Substances 0.000 claims description 5
- 239000013536 elastomeric material Substances 0.000 claims description 3
- -1 polytetrafluoroethylene Polymers 0.000 claims description 2
- 230000001050 lubricating effect Effects 0.000 abstract description 3
- 229940058401 polytetrafluoroethylene Drugs 0.000 description 9
- 239000000463 material Substances 0.000 description 4
- 230000000712 assembly Effects 0.000 description 2
- 238000000429 assembly Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000002131 composite material Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 230000003014 reinforcing effect Effects 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J15/00—Sealings
- F16J15/16—Sealings between relatively-moving surfaces
- F16J15/32—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings
- F16J15/3204—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings with at least one lip
- F16J15/322—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings with at least one lip supported in a direction perpendicular to the surfaces
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J15/00—Sealings
- F16J15/16—Sealings between relatively-moving surfaces
- F16J15/32—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings
- F16J15/324—Arrangements for lubrication or cooling of the sealing itself
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16J—PISTONS; CYLINDERS; SEALINGS
- F16J15/00—Sealings
- F16J15/56—Other sealings for reciprocating rods
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Sealing With Elastic Sealing Lips (AREA)
- Sealing Devices (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
The seal assembly for separating a region at a higher pressure p1 from a lower pressure region p2 has a first, elastomeric, sealing element 5 having a sealing lip engaging the surface of a rod 2 and a second, PTFE, sealing element 6 having a substantially rectangular shape in cross-section. The PTFE element 6 has an inclined surface 7 meeting the rod at an angle a and a lubricating pocket 9 is formed between the two sealing elements, improving the friction behaviour of the seal.
Description
2353336 Sealina assemblv for sealinQ a rod-like element The invention
relates to a sealing assembly for sealing a rod-like element, wherein the sealing assembly maintains a pressure difference which prevails between the two zones which are separated by the sealing assembly.
Sealing assemblies of the type defined have been known for a long time and are often called gas spring seals. They have the purpose of sealing a guided and sealed rod in such a way that a pressure difference can be maintained between the two sides of the seal.
In most instances involving a gas spring seal an elastomeric sealing lip is used which is intended to achieve the desired effect, i.e. maintaining a pressure difference. However, known sealing assemblies of this type have the disadvantage that, depending on the gas spring pressure, the breakaway force and friction can attain very high values which can be harmful.
Therefore, the object of the invention is to develop a sealing assembly of the type defined, in such a way that the breakaway force and friction values of the assembly remain low even if the pressure differences to be maintained are high.
The invention therefore provides a sealing assembly for sealing a rodlike element, wherein the sealing assembly maintains a pressure difference which prevails between two areas which areas are separated by the sealing assembly, wherein a first sealing element in the form of a sealing lip of elastomeric material which sealingly abuts against the rodlike element, and a second sealing element in the form of a seal made of polytetraf luoroethylene (PTFE), wherein the second sealing element is of substantially rectangular shape in crosssection.
Preferably, the first sealing element faces that zone in which the higher pressure prevails. Furthermore, the second 2 sealing element is preferably arranged in the immediate vicinity of the first sealing element.
According to the invention, therefore, instead of the known conventional elastomeric sealing lip a two-component design for the sealing assembly is proposed. Furthermore, an elastomeric sealing lip is provided on the front side thereof, facing the pressure zone. In operation, this lip is lubricated very satisfactorily by the upstream oil cushion which builds up and, at the same time, it has very good sealing properties against the gas pressure, as a result of its high degree of elasticity and low set behaviour. According to the invention, a second sealing location, which is made of PTFE material, is provided downstream of the elastomeric sealing lip. Boundary friction prevails for the most part in this zone of the gas spring seal so that the very good sliding friction properties of the PTFE material are utilised. At the same time, the contact pressure on the material is distinctly lower here than in the front zone of the seal, i.e. in the vicinity of the elastomeric sealing lip, so that the creep tendency of the PTFE material under high pressure loading does not have any appreciable relevance.
In a further embodiment, it is provided that the surface of the second sealing element facing the rod-like element is arranged at least partly at an angle (c() to the surface of the rod-like element. This angle (co may be between 0. 5' and 30'.
The sealing assembly according to the invention performs particularly well if a lubricant pocket is provided between the first sealing element and the second sealing element. A further reduction in friction can be achieved by the use of this lubricant pocket.
One example of an embodiment of the sealing assembly is illustrated in the drawings, in which:- 3 Figure 1 shows in detail a section through the sealing assembly and the contact relationships with a rodlike element to be sealed, and Figure 2 shows the entire seal in its mounted position.
According to Figure 1, the sealing assembly 1 abuts with friction against a rod-like element 2 and seals it. In the upper zone 3 of the rod-like element 2 a higher pressure p, prevails than in the lower zone 4, where the pressure P2 'S lower. Consequently, the sealing assembly 1 seals the rod-like element 2 with respect to the pressure difference ' P P1- P2 For this purpose, the sealing assembly 1 comprises, in a known manner, a first sealing element 5 in the form of an elastomeric sealing lip. However, a second sealing element 6 of polytetrafluoroethylene (PTFE) is disposed downstream of the first sealing element in spatial proximity thereto. As is clearly evident from Figure 1, the PTFE seal 6 is of substantially rectangular shape in cross-section, even if the seal is slightly distorted whereby one portion of the seal 6 can be flattened by an angle a. The sealing element 6 is located in its axial position by a piston guide element 11, on one side, and by the elastomeric sealing lip 5, on the other side.
In this case the surface 7 of the second sealing element, which faces the rod-like element 2, is partly flattened by the angle a relative to the surface 8 of the rodlike element 2. Especially good lubricating conditions can thereby be achieved.
The lubricating conditions are also improved in particular by providing a lubricant pocket 9 between the elastomeric sealing lip 5 and the PTFE seal 6; a further reduction in the friction between the sealing assembly 1 and the rod-like element 2 can be achieved thereby. In particular, a further reduction in friction can be obtained as a result of the lubricant pocket 9 which, after a number of strokes, is 4 partly filled with the oil remaining in the surface roughness of the piston rod element.
The proposed design of a sealing assembly makes it possible to provide a composite seal which is optimised with respect to friction. The sealing assembly is of compact construction and, therefore, is suitable for longterm stable As is evident from Figure 2, the entire sealing assembly can be mounted in a tubular element 12 which effects satisfactory location of the sealing assembly 1 relative to the rod-like element 2. The sealing assembly 1 itself is stabilised by a reinforcing element 10 which, in the example of embodiment, is disposed within the elastomeric material of the first sealing element 5.
Claims (7)
1. A sealing assembly for sealing a rod-like element, wherein the sealing assembly maintains a pressure difference which prevails between two areas which areas are separated by the sealing assembly, wherein a first sealing element in the form of a sealing lip of elastomeric material which sealingly abuts against the rod-like element, and a second sealing element in the form of a seal made of polytetrafluoroethylene (PTFE), wherein the second sealing element is of substantially rectangular shape in cross-section.
2. A sealing assembly according to Claim 1, wherein the first sealing element faces that zone in which the higher pressure prevails.
3. A sealing assembly according to Claim 1 or 2, wherein the second sealing element is arranged in the immediate vicinity of the first sealing element.
4. A sealing assembly according to any one of Claims 1 to 3, wherein the surface of the second sealing element facing the rod-like element is arranged at least partly at an angle (a) to the surface of the rod-like element.
5. A sealing assembly according to Claim 4, wherein the angle (oo is between 0.51 and 301.
6. A sealing assembly according to any one of Claims 1 to 5, wherein a lubricant pocket is provided between the first sealing element and the second sealing element.
7. A sealing assembly substantially as hereinbefore described with reference to or as shown in the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19938785A DE19938785A1 (en) | 1999-08-16 | 1999-08-16 | Sealing arrangement for sealing a rod-shaped element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB0020205D0 GB0020205D0 (en) | 2000-10-04 |
| GB2353336A true GB2353336A (en) | 2001-02-21 |
Family
ID=7918547
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0020205A Withdrawn GB2353336A (en) | 1999-08-16 | 2000-08-16 | Seal assembly for a rod |
Country Status (4)
| Country | Link |
|---|---|
| DE (1) | DE19938785A1 (en) |
| FR (1) | FR2797672A1 (en) |
| GB (1) | GB2353336A (en) |
| IT (1) | IT1320799B1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2417299A (en) * | 2003-09-18 | 2006-02-22 | Cooper Cameron Corp | A seal assembly capable of low temperature service |
| EP2060834A1 (en) * | 2006-09-04 | 2009-05-20 | Kyb Corporation | Oil seal for reciprocation motion |
| AT509560B1 (en) * | 2010-02-15 | 2012-02-15 | Hoerbiger Kompressortech Hold | CIRCUIT ARRANGEMENT AND COMPRESSOR WITH SUCH A CUT-OFF ARRANGEMENT |
| FR2968056A1 (en) * | 2010-11-25 | 2012-06-01 | Bosch Gmbh Robert | ROOF SECTION SEAL SLEEVE TRIM |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2196710A1 (en) * | 2008-12-12 | 2010-06-16 | Carl Freudenberg KG | Seal arrangement |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1066857A (en) * | 1962-12-21 | 1967-04-26 | Johns Manville | Fluid seal |
| GB1409266A (en) * | 1972-06-22 | 1975-10-08 | Walker Co Ltd James | Annular fluid pressure seals |
| GB2141205A (en) * | 1983-06-08 | 1984-12-12 | Greene Tweed & Co Inc | Antifriction fluid seal assembly |
| GB2219050A (en) * | 1988-05-26 | 1989-11-29 | Magnaghi Milano Spa | Fluid-tight sealing assembly for axially slidable cylindrical coaxial parts |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5921556A (en) * | 1996-10-04 | 1999-07-13 | Avm, Inc. | Seal for gas springs and the like |
-
1999
- 1999-08-16 DE DE19938785A patent/DE19938785A1/en not_active Withdrawn
-
2000
- 2000-08-10 FR FR0010502A patent/FR2797672A1/en not_active Withdrawn
- 2000-08-10 IT IT2000TO000795A patent/IT1320799B1/en active
- 2000-08-16 GB GB0020205A patent/GB2353336A/en not_active Withdrawn
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1066857A (en) * | 1962-12-21 | 1967-04-26 | Johns Manville | Fluid seal |
| GB1409266A (en) * | 1972-06-22 | 1975-10-08 | Walker Co Ltd James | Annular fluid pressure seals |
| GB2141205A (en) * | 1983-06-08 | 1984-12-12 | Greene Tweed & Co Inc | Antifriction fluid seal assembly |
| GB2219050A (en) * | 1988-05-26 | 1989-11-29 | Magnaghi Milano Spa | Fluid-tight sealing assembly for axially slidable cylindrical coaxial parts |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2417299A (en) * | 2003-09-18 | 2006-02-22 | Cooper Cameron Corp | A seal assembly capable of low temperature service |
| GB2417299B (en) * | 2003-09-18 | 2006-12-06 | Cooper Cameron Corp | Annular seal |
| US7740248B2 (en) | 2003-09-18 | 2010-06-22 | Cameron International Corporation | Annular seal |
| US8235396B2 (en) | 2003-09-18 | 2012-08-07 | Cameron International Corporation | Annular seal |
| US8622398B2 (en) | 2003-09-18 | 2014-01-07 | Cameron International Corporation | Annular seal |
| EP2060834A1 (en) * | 2006-09-04 | 2009-05-20 | Kyb Corporation | Oil seal for reciprocation motion |
| EP2060834A4 (en) * | 2006-09-04 | 2012-03-21 | Kyb Corp | Oil seal for reciprocation motion |
| US8282107B2 (en) | 2006-09-04 | 2012-10-09 | Kyb Corporation | Oil seal for reciprocation motion |
| AT509560B1 (en) * | 2010-02-15 | 2012-02-15 | Hoerbiger Kompressortech Hold | CIRCUIT ARRANGEMENT AND COMPRESSOR WITH SUCH A CUT-OFF ARRANGEMENT |
| FR2968056A1 (en) * | 2010-11-25 | 2012-06-01 | Bosch Gmbh Robert | ROOF SECTION SEAL SLEEVE TRIM |
Also Published As
| Publication number | Publication date |
|---|---|
| DE19938785A1 (en) | 2001-03-22 |
| ITTO20000795A1 (en) | 2002-02-10 |
| ITTO20000795A0 (en) | 2000-08-10 |
| GB0020205D0 (en) | 2000-10-04 |
| FR2797672A1 (en) | 2001-02-23 |
| IT1320799B1 (en) | 2003-12-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |