- Email: [email protected]
Bearing seal assemblies
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PATENTS
Bearing seal assemblies Assignee: Roller Bearing Industries Inc, USA This invention relates to bearing assemblies, and in particular to devices and methods for sealing bearing assemblies used in railway vehicles or other similar applications. Bearing assemblies allow a wheel to rotate relative to a shaft (also called an axle journal). They are often sealed to maintain a lubricant within the bearing assembly and to prevent dirt, sand and moisture from entering the bearing assembly. The seal is typically formed of an annular rubber lip seal which rotates about the shaft. Figure 1 shows a conventional embodiment of a seal (200) for a bearing assembly (100). The bearing assembly may include, for example, a journal shaft (101) supporting a wear ring (106), an inner race (103), and a backing ring (102). The inner race (103) may support, for example, a tapered roller bearing (105) and an outer race (104). Sealing the grease in the tapered roller bearing is a seal including an upper seal support (202), a lower seal support (209), and a plurality of rubber projections which include an inner rubber seal (203) with a grease seal portion (206), a dust seal (205), and a non-contact side seal (204). The prior art, however, suffers from a number of deficiencies, including a propensity for moisture to enter the bearings and degrade the seal. As a result, there is a need for an improved bearing seal that reduces torque, i.e. is a lowtorque seal, while at the same time maintaining the high reliability normally associated with higher torque seals. Aspects of the present invention overcome one or more of the above-mentioned problems by using improved seal assemblies
and/or approved sealing surfaces and/or materials. For example, an aspect of the present invention utilizes a polymeric main seal such that grease is permanently sealed in the tapered roller bearings. In the most preferred embodiments, Teflon or PTFE is utilized to provide the main seal. The main seal may extend horizontally from an upper seal support and contact and ride along an extended portion of a horizontal lower seal support. In other aspects of the present invention, a rain shield is provided over the gap between the upper seal support and the lower seal support. In further aspects of the invention, a side seal is a contact side seal which runs and/or contacts the vertical surface of the lower seal support. In still further aspects of the invention, a non-contact seal is provided that rotates spaced from the surface of the horizontal surface of the lower seal support. The non-contact seal may include two closely spaced fingers or tines with their lengths substantially longer than their widths. This improves the resiliency of the tines, improving reliability. Referring to Figure 2, a seal may be formed such that it is compatible with the tapered roller bearing assembly including the tapered roller bearing, outer race, inner race, journal shaft, wear ring and backing ring of Figure 1. As illustrated in Figure 2, the seal may include, for example, an upper support seal (2) opposed to a lower seal support (9). The upper seal support may include a water shield (7). The water shield can be of any configuration, but is preferably formed of a rubber compound and extends horizontally out of a vertical surface of the upper seal support.
Figure 1. A conventional seal assembly, from US 6485185.
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Figure 2. The seal described in US 6485185 is compatible with the conventional bearing shown in Figure 1.
Alternatively, other configurations are possible, such as the watershield being on the lower seal support (9) and covering in the lower seal support and the upper seal support (2), and extending horizontally from the horizontal portion of the upper seal support. However, where the lower seal support rotates, it is preferred to have the water shield (7) on the upper seal support, and extending over the space between the lower seal support and the upper seal support. The rain shield is preferably made from a rubber compound such as Nitro, manufactured by Paulstra. This has the beneficial effect of preventing moisture buildup from occurring within the seal and early failure of the seal. The seal may also include a side seal (4) disposed such that is in tight contact with the lower seal support (9) extending from a vertical portion of the upper seal support (2). A tight contact between the side seal and the vertical portion of the lower seal support has the beneficial effect of substantially reducing moisture buildup under the side seal. Additionally, the lower moisture buildup allows for the sealing surfaces of the fingerlike tines on the non-contact seal (5) to be slightly spaced from the lower seal support. In this manner, the non-contact seal can serve as a dust trap while substantially reducing the torque of the overall bearing seal. In exemplary embodiments, the tines of the non-contact seal may be the same length and/or spaced a uniform distance from the lower seal support. However, where the tines are different lengths and/or different distances from the lower seal support (for example, the outer tine is longer than the inner tine), a more effective seal results. The grease seal (6) may be formed of a
Sealing Technology January 2003
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CALENDAR
Events Calendar 5–9 February 2003
4–6 March 2003
NFPA 2003 Spring Conference
Chemtex & Corrosion Middle East 2003
Westin Rio Mar Beach Resort, Puerto Rico Contact: National Fluid Power Association, 3333 N. Mayfair Road, Milwaukee, WI 53222-3219, USA. Tel: +1 414 778 3344 Fax: +1 414 778 3361 Web: www.nfpa.com
27 February 2003 VMA Asbestos Litigation Seminar Washington, District of Columbia, USA Contact: Valve Manufacturers Association of America, 1050 17th Street NW, Suite 280, Washington, DC 20036, USA. Tel: +1 202 331 8105 Fax: +1 202 296 0378 Web: www.vma.org
3–6 March 2003 SAE 2003 World Congress Detroit, Michigan, USA Contact: SAE World Headquarters, 400 Commonwealth Drive, Warrendale, PA 15096-0001 USA. Tel: +1 724 776 4841 Fax: +1 724 776 5760 Web: www.sae.org/congress
Dubai, United Arab Emirates Contact: International Expo-Consults, PO Box 50006, Dubai, United Arab Emirates. Tel: +971 4 3435777 Fax: +971 4 3436115 Email: [email protected] Web: www.iecdubai.com
17–20 March 2003 20th International Pump Users Symposium Houston, Texas, USA Contact: Joanne Burnett, Turbomachinery Laboratory, Texas A&M University, 3254 TAMU, College Station, TX 77843-3254, USA. Tel: +1 979 845 2924 Fax: +1 979 845 1835 Email: [email protected] Web: turbolab.tamu.edu/pumpshow/ pump.html
7–8 April 2003 Deformation, Yield and Fracture of Polymers Churchill College, Cambridge, UK Contact: Melanie Boyce, Institute of
PTFE material which forms the main barrier seal of the seal. The PTFE seal may be corrugated such as shown in Figures 2 and 3. Referring specifically to Figure 3, this shows a more detailed description of the seal in accordance with aspects of the present invention. This embodiment is substantially similar to the embodiment shown in Figure 2, and so will not be described in further detail. In exemplary embodiments of the invention, a highly reliable and efficient seal is provided without the need for a garter spring, which substantially increases the torque of the seal. The grease seal (6) provides a highly efficient seal while at the same time providing a very low torque. This torque can be reduced even further by the use of channels in the primary seal. These channels, in addition to reducing the contact area between the primary seal and the lower seal support (9), also serve to channel grease and lubrication across the entire length of the PTFE seal. Thus, even though the seal may occupy an extended horizontal surface of the lower support, the channels provide a very low torque on the overall seal assembly. Modifications can be made to the invention; for example, the upper and lower seal shown in
Sealing Technology January 2003
Materials, Minerals & Mining (IOM3), Carlton House Terrace, London SW1Y 5DB, UK. Tel: +44 20 7451 7303 Fax: +44 20 7839 2289 Email: [email protected] Web: http://www.materials.org.uk/ iomevents/dyfp2003
8–10 April 2003 17th International Conference on Fluid Sealing York, UK Contact: Katie Coupar-Evans, Conference Organiser, BHR Group Ltd, Cranfield, Bedford MK43 0AJ, UK. Tel: +44 1234 750422 Fax: +44 1234 750074 Email: [email protected] Web: http://www.bhrgroup.com/ confsite/fs03home.htm
28 April–1 May 2003 STLE 58th Annual Meeting & Exhibit New York, USA Contact: Society of Tribologists & Lubrication Engineers, 840 Busse Highway, Park Ridge, IL 60068-2376, USA. Tel: +1 847 825 5536
Figure 3 may be inverted in appropriate circumstances. Additionally, by slight modifications, it may be arranged such that the lower seal support and the upper seal support are either stationary and/or rotate. Other materials can be used other than those mentioned here, particularly with respect to the polymeric
Fax: +1 847 825 1456 Web: http://www.stle.org/ annual_meeting_2003/am_2003.htm
7–9 May 2003 8th Scandinavian International Conference on Fluid Power, SICFP 2003 Tampere, Finland Contact: SICFP 2003 Secretariat, Edutech, Tampere University of Technology, PO Box 589, FIN-33101 Tampere, Finland. Tel: +358 3 3115 2400 Fax: +358 3 3115 2164 Email: [email protected] Web: www.sicfp03.tut.fi
19–22 May 2003 IISRP 44th Annual General Meeting Beijing, China Contact: International Institute of Synthetic Rubber Producers, 2077 South Gessner Road, Suite 133, Houston, TX 77063, USA. Tel: +1 713 783 7511 Fax: +1 713 783 7253 Email: [email protected] Web: www.iisrp.com
PTFE seal. However, it has been found that the PTFE material provides substantial reduction in seal torque. Patent number: US 6485185 Inventors: D.T. Conway, P.G. Steets, M.E. Paul, P.R. Price, T.K. Chu Publication date: 26 November 2002
Figure 3. An expanded view of the seal illustrated in Figure 2, from US 6485185.
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22/01/2003
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PATENTS
Bearing seal assemblies Assignee: Roller Bearing Industries Inc, USA This invention relates to bearing assemblies, and in particular to devices and methods for sealing bearing assemblies used in railway vehicles or other similar applications. Bearing assemblies allow a wheel to rotate relative to a shaft (also called an axle journal). They are often sealed to maintain a lubricant within the bearing assembly and to prevent dirt, sand and moisture from entering the bearing assembly. The seal is typically formed of an annular rubber lip seal which rotates about the shaft. Figure 1 shows a conventional embodiment of a seal (200) for a bearing assembly (100). The bearing assembly may include, for example, a journal shaft (101) supporting a wear ring (106), an inner race (103), and a backing ring (102). The inner race (103) may support, for example, a tapered roller bearing (105) and an outer race (104). Sealing the grease in the tapered roller bearing is a seal including an upper seal support (202), a lower seal support (209), and a plurality of rubber projections which include an inner rubber seal (203) with a grease seal portion (206), a dust seal (205), and a non-contact side seal (204). The prior art, however, suffers from a number of deficiencies, including a propensity for moisture to enter the bearings and degrade the seal. As a result, there is a need for an improved bearing seal that reduces torque, i.e. is a lowtorque seal, while at the same time maintaining the high reliability normally associated with higher torque seals. Aspects of the present invention overcome one or more of the above-mentioned problems by using improved seal assemblies
and/or approved sealing surfaces and/or materials. For example, an aspect of the present invention utilizes a polymeric main seal such that grease is permanently sealed in the tapered roller bearings. In the most preferred embodiments, Teflon or PTFE is utilized to provide the main seal. The main seal may extend horizontally from an upper seal support and contact and ride along an extended portion of a horizontal lower seal support. In other aspects of the present invention, a rain shield is provided over the gap between the upper seal support and the lower seal support. In further aspects of the invention, a side seal is a contact side seal which runs and/or contacts the vertical surface of the lower seal support. In still further aspects of the invention, a non-contact seal is provided that rotates spaced from the surface of the horizontal surface of the lower seal support. The non-contact seal may include two closely spaced fingers or tines with their lengths substantially longer than their widths. This improves the resiliency of the tines, improving reliability. Referring to Figure 2, a seal may be formed such that it is compatible with the tapered roller bearing assembly including the tapered roller bearing, outer race, inner race, journal shaft, wear ring and backing ring of Figure 1. As illustrated in Figure 2, the seal may include, for example, an upper support seal (2) opposed to a lower seal support (9). The upper seal support may include a water shield (7). The water shield can be of any configuration, but is preferably formed of a rubber compound and extends horizontally out of a vertical surface of the upper seal support.
Figure 1. A conventional seal assembly, from US 6485185.
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Figure 2. The seal described in US 6485185 is compatible with the conventional bearing shown in Figure 1.
Alternatively, other configurations are possible, such as the watershield being on the lower seal support (9) and covering in the lower seal support and the upper seal support (2), and extending horizontally from the horizontal portion of the upper seal support. However, where the lower seal support rotates, it is preferred to have the water shield (7) on the upper seal support, and extending over the space between the lower seal support and the upper seal support. The rain shield is preferably made from a rubber compound such as Nitro, manufactured by Paulstra. This has the beneficial effect of preventing moisture buildup from occurring within the seal and early failure of the seal. The seal may also include a side seal (4) disposed such that is in tight contact with the lower seal support (9) extending from a vertical portion of the upper seal support (2). A tight contact between the side seal and the vertical portion of the lower seal support has the beneficial effect of substantially reducing moisture buildup under the side seal. Additionally, the lower moisture buildup allows for the sealing surfaces of the fingerlike tines on the non-contact seal (5) to be slightly spaced from the lower seal support. In this manner, the non-contact seal can serve as a dust trap while substantially reducing the torque of the overall bearing seal. In exemplary embodiments, the tines of the non-contact seal may be the same length and/or spaced a uniform distance from the lower seal support. However, where the tines are different lengths and/or different distances from the lower seal support (for example, the outer tine is longer than the inner tine), a more effective seal results. The grease seal (6) may be formed of a
Sealing Technology January 2003
jan03 sealing technology.qxd
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Page 15
CALENDAR
Events Calendar 5–9 February 2003
4–6 March 2003
NFPA 2003 Spring Conference
Chemtex & Corrosion Middle East 2003
Westin Rio Mar Beach Resort, Puerto Rico Contact: National Fluid Power Association, 3333 N. Mayfair Road, Milwaukee, WI 53222-3219, USA. Tel: +1 414 778 3344 Fax: +1 414 778 3361 Web: www.nfpa.com
27 February 2003 VMA Asbestos Litigation Seminar Washington, District of Columbia, USA Contact: Valve Manufacturers Association of America, 1050 17th Street NW, Suite 280, Washington, DC 20036, USA. Tel: +1 202 331 8105 Fax: +1 202 296 0378 Web: www.vma.org
3–6 March 2003 SAE 2003 World Congress Detroit, Michigan, USA Contact: SAE World Headquarters, 400 Commonwealth Drive, Warrendale, PA 15096-0001 USA. Tel: +1 724 776 4841 Fax: +1 724 776 5760 Web: www.sae.org/congress
Dubai, United Arab Emirates Contact: International Expo-Consults, PO Box 50006, Dubai, United Arab Emirates. Tel: +971 4 3435777 Fax: +971 4 3436115 Email: [email protected] Web: www.iecdubai.com
17–20 March 2003 20th International Pump Users Symposium Houston, Texas, USA Contact: Joanne Burnett, Turbomachinery Laboratory, Texas A&M University, 3254 TAMU, College Station, TX 77843-3254, USA. Tel: +1 979 845 2924 Fax: +1 979 845 1835 Email: [email protected] Web: turbolab.tamu.edu/pumpshow/ pump.html
7–8 April 2003 Deformation, Yield and Fracture of Polymers Churchill College, Cambridge, UK Contact: Melanie Boyce, Institute of
PTFE material which forms the main barrier seal of the seal. The PTFE seal may be corrugated such as shown in Figures 2 and 3. Referring specifically to Figure 3, this shows a more detailed description of the seal in accordance with aspects of the present invention. This embodiment is substantially similar to the embodiment shown in Figure 2, and so will not be described in further detail. In exemplary embodiments of the invention, a highly reliable and efficient seal is provided without the need for a garter spring, which substantially increases the torque of the seal. The grease seal (6) provides a highly efficient seal while at the same time providing a very low torque. This torque can be reduced even further by the use of channels in the primary seal. These channels, in addition to reducing the contact area between the primary seal and the lower seal support (9), also serve to channel grease and lubrication across the entire length of the PTFE seal. Thus, even though the seal may occupy an extended horizontal surface of the lower support, the channels provide a very low torque on the overall seal assembly. Modifications can be made to the invention; for example, the upper and lower seal shown in
Sealing Technology January 2003
Materials, Minerals & Mining (IOM3), Carlton House Terrace, London SW1Y 5DB, UK. Tel: +44 20 7451 7303 Fax: +44 20 7839 2289 Email: [email protected] Web: http://www.materials.org.uk/ iomevents/dyfp2003
8–10 April 2003 17th International Conference on Fluid Sealing York, UK Contact: Katie Coupar-Evans, Conference Organiser, BHR Group Ltd, Cranfield, Bedford MK43 0AJ, UK. Tel: +44 1234 750422 Fax: +44 1234 750074 Email: [email protected] Web: http://www.bhrgroup.com/ confsite/fs03home.htm
28 April–1 May 2003 STLE 58th Annual Meeting & Exhibit New York, USA Contact: Society of Tribologists & Lubrication Engineers, 840 Busse Highway, Park Ridge, IL 60068-2376, USA. Tel: +1 847 825 5536
Figure 3 may be inverted in appropriate circumstances. Additionally, by slight modifications, it may be arranged such that the lower seal support and the upper seal support are either stationary and/or rotate. Other materials can be used other than those mentioned here, particularly with respect to the polymeric
Fax: +1 847 825 1456 Web: http://www.stle.org/ annual_meeting_2003/am_2003.htm
7–9 May 2003 8th Scandinavian International Conference on Fluid Power, SICFP 2003 Tampere, Finland Contact: SICFP 2003 Secretariat, Edutech, Tampere University of Technology, PO Box 589, FIN-33101 Tampere, Finland. Tel: +358 3 3115 2400 Fax: +358 3 3115 2164 Email: [email protected] Web: www.sicfp03.tut.fi
19–22 May 2003 IISRP 44th Annual General Meeting Beijing, China Contact: International Institute of Synthetic Rubber Producers, 2077 South Gessner Road, Suite 133, Houston, TX 77063, USA. Tel: +1 713 783 7511 Fax: +1 713 783 7253 Email: [email protected] Web: www.iisrp.com
PTFE seal. However, it has been found that the PTFE material provides substantial reduction in seal torque. Patent number: US 6485185 Inventors: D.T. Conway, P.G. Steets, M.E. Paul, P.R. Price, T.K. Chu Publication date: 26 November 2002
Figure 3. An expanded view of the seal illustrated in Figure 2, from US 6485185.
15