Tecnologia

Rotary Seals

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V—Ring

n V-RING
n General
minimum, resulting in excellent wear characteristics and extended seal life. Once breakaway friction is overcome, the friction reduce steadily until around the 10 - 15 m/s range, when it reduces quite quickly. In the 15 - 20 m/s range the friction reduces to zero. The V—Ring then serves as a clearance seal anddeflector. The power loss due to seal friction develops as shown in Fig. 54. The flexible lip and hinge allow the V—Ring to function even in the presence of a certain amount of run-out, eccentricity and shaft misalignment. Contact our local TSS company for advice on these and other application issues. V—Rings are made entirely of rubber without fabric or sheet metal reinforcement. They are,therefore, particularly easy to install. V—Rings can be stretched and, depending on size, installed over flanges, pulleys and bearing housings without costly dismantling. For larger sizes they can even be supplied as cut rings and joined by vulcanisation on site. Figure 53 Method of operation of the V—Ring Design V—Rings are available in seven standard cross-sections to meet various space andapplication requirements. The cross-sections of profiles A and S increase with the shaft diameter, whilst the other types have the same crosssection for the whole diameter range. Profile A is the most common and available for shaft diameters from 2.7 to 2020 mm, inclusive. Profile S is wide and tapered, which provides a very firm hold on the shaft. The rings are available for shaft diameters from 4.5 to 210mm. Profiles L and LX have narrow axial cross sections making them suitable for compact arrangements and are often used in combination with labyrinth seals. Available for shaft diameters from 105 (135 for LX) to 2025 mm. Profiles RME, RM and AX are heavy duty V—Rings that are designed primarily for large high speed bearing arrangements, I. E. rolling mill and papermaking machine applications.Additionally they can be used as secondary seals for heavy duty applications where the primary seal has to be protected against water and or particulate contamination. The RME, RM and AX types can be axially and radially located on the shaft with the especially designed clamping bands (see page 148). Available for shaft diameters from 300 mm and up. Larger V—Ring sizes are available as spliced seals.For more details please contact your local TSS company.

The V-RING is a unique all-rubber seal for rotary shafts. Developed in the 1960’s by FORSHEDA AB, it has been used successfully by OEMs and on the replacement market world wide in a broad range of applications. The V—Ring is the perfect seal to prevent the ingress of dirt, dust, water or combinations of these media while positivelyretaining grease. With its unique design and performance the V—Ring can be used with a wide range of bearing types. It can also be used as a secondary seal to protect primary seals that do not perform well in hostile environments. Description and advantages The V—Ring is normally stretched and mounted directly on the shaft, where it is held in position by the inherent tension of the rubber body. Itrotates with the shaft and seals axially against a stationary counterface, perpendicular to the shaft. The counterface can be the side wall of a bearing or a washer, stamping, bearing housing, or even the metal case of an oil seal. The sealing lip is flexible and applies only a relatively light contact pressure against the counter-face and yet is still sufficient to maintain the sealing function. Thelow contact pressure (that varies with the fitted width) allows the seal to run dry in many applications. Due to influence of the centrifugal force, the contact pressure of the lip decreases with increased speed. This means that frictional losses and heat are kept to a

Latest information available at www.tss.trelleborg.com Edition April 2007

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V—Ring

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