GB2226091A - Seal ring - Google Patents

Description

Seal ring The invention refers to a seal ring according to the main

expression in claim 1.

The installation procedures required for seal rings differ so greatly that mistakes occur repeatedly when fitting the seal ring. The seal ring itself is therefore often damaged.

This applies particularly to seal rings whose lips consist of polytetrafluoroethylene. Such materials have a so-called "memory effect" which means that the seal lip has a tendency to change in the direction of its undistorted condition. This therefore reduces its inside diameter and makes reliable installation of the seal ring difficult.

As the correct installation tools are often not available when replacing seal rings during the course of customer service, mistakes are also often made upon installation and replacement of the seal ring.

In the industrial installation of components and seal rings some parts are often pre-assembled, for example consisting of the seal ring and the bearings. This produces an intermediate storage time in which the components can easily become contaminated or lubricant can be lost. Also other interference factors can negatively affect such components.

The invention is based upon the task of providing a seal ring of this type so that installation is easier, mistakes are avoided and pre- assembled components are protected against damage.

With a seal ring of the type involved in the invention this task 5 is solved with the characteristics of claim 1.

As a consequence of the design involved the seal ring is preassembled with the protecting part to form an assembly which, simply held on bearings, can be transported and easily and quickly fitted. The protecting parts protect the seal ring against contamination and the seal lip against damage and deformation. As the seal lip lies in contact with the protecting part the diameter of the seal lip cannot become enlarged during a longer period of storage and in fact it is preferably reduced. The protection part is especially beneficial for seal lips made 1-5 of polytetrafluoroethylene whose memory effect cannot have any negative effects, due to the presence of the protection part. The seal ring can therefore be fitted easily without the risk of damage. Even when using unsuitable installation equipment the seal ring is reliably protected against damage by the protection part and also loss of coolant and other disruptive factors are avoided.

Further characteristics of the invention result from the other claims, the description and the drawing.

The invention is described below in more detail with the aid of several design examples illustrated in the drawing. This shows:

Fig. 1: An axial cross section of a seal ring according to the invention, with a mounting sleeve.

Figs. 2 & 3: A further design form in each case of a seal ring according to the invention with a mounting sleeve, shown according to fig. 1.

The seal ring (1) according to fig. 1 has a cup-shaped support section (2) made of metal or plastic, a sleeve (3) and a seal lip (4) which preferably consists of polytetrafluoroethylene. The seal lip (4) is secured with a radial ring (4a) on the sleeve (3) at the level of the base (2a) of the support section (2).

The seal ring (1) is seated with a base (5) on a circular shoulder (6) of a mounting sleeve (7), whereby the shoulder protrudes radially outwards. It has a cylindrical shell (8) which is extended in a slightly conical shape and which supports the seal lip (4) of the seal ring (1). The edge (9) of the lip (4) lies at approximately the same height as the inside (10) of the base (11) of the mounting sleeve (7).

The circular shoulder (6) divides the cylindrical shell (8) into a shorter and a longer section (13 and 14). The axial length of the shell section (13) between the base (11) and the circular 2q shoulder (6) corresponds approximately to the axial length of the seal ring (1).

The other section of the shell (14) is several times longer than the section (13). Its outside and inside diameters preferably decrease constantly from the ring shoulder (6) in the direction towards its free end. The outer surface (15) of the section (14) preferably has a rippled profile on its outer thirdy across the axis of the shell (8), whereby the mounting sleeve (7) is held simply and reliably with a pressing tool and can be inserted together w ith the seal ring (1) into an installation opening.

-4 The seal ring (1) illustrated serves as a bearing seal. The bearing (not shown) has a mounting into which the seal ring (1) is fitted with the mounting sleeve (7). The pre-assembled unit produced in this way is later fitted to the relevant equipment. The mounting sleeve (7) protects the seal ring (1) and the bearing, for example, against contamination in the pre-assembled unit. The mounting sleeve in particular protects the sensitive seal lip (4) against damage. At the same time the mounting sleeve (7) is used as an aid upon installation of the seal ring (1). The mounting sleeve (7) is removed by.hand in the direction of the arrow (P) directly before installing the unit in the equipment. The use of the mounting sleeve (7) means that installation mistakes can be reliably avoided, thus guaranteeing that the seal ring is fitted correctly. The seal ring (1) with the cylindrical outside surface (17) of the shell (3) is pressed firmly into the installation cavity.

The pre-assembled bearing and seal ring unit can also be protected reliably against contamination, loss of lubricant and other disruptive factors with the mounting sleeve (7) during intermediate storage. It is possible to treat the seal ring (1) with the mounting sleeve (7) fitted as an item of bulk material because the mounting sleeve (7) protects the seal ring (1) in the manner described. The unit described also permits cost savings and is also environmentally friendly, because in industrial applications the mounting sleeve (7) adjusted by the seal ring manufacturer and matched to the relevant application preferably consists of plastic and can be used several times.

In the design according to fig. 2 the seal ring (1) is a shaft seal ring which has two lips (V, 4a') which point in opposite directions. In this case the sleeve (V) mainly has a protective function. The sleeve (V) is slightly shorter than the seal ring (11).

1 The cylindrical shell (8') of the sleeve (7') changes at the end close to the seal lip (4') into a circular flange (11') which is directed radially inwards and at its end close to the seal lip (4a') it changes into a flange (6') which is directed radially outwards. The circular flange (6') changes into the shell (8') via a changeover section (19) which is approximately semicircular in its axial cross-section.

The section (19) forms a circular external groove (19a) into which the one seal lip (4a') protrudes. Like the seal lip (4'), this lies on the outer shell surface (20). The seal ring lies with its base (5') on the circular flange (V). In the radial direction it is only slightly narrower than the seal ring (V) so that this is ideally protected by the circular flange (6'). The two seal lips (4', 4a') lie against the sleeve (V) and are protected.

As in the previous design, the outside diameter of the sleeve (71) in the area of the seal lips (V, 4a') is preferably lower than the required inside diameter of the seal lips (4', 4a'). This ensures that the seal lips remain at a constant diameter even if the seal ring (V) is stored for a longer period, so that the seal ring (V) can be fitted perfectly. It is also possible to choose the outside diameter of the sleeve (V) in the area of the seal lips (4', 4a') so that it is equal to the inside diameter of the seal lips or the shaft diameter! The sleeve (V) is kept in stock with the seal ring (V) fitted. The sleeve (V) therefore protects the seal ring (V) against damage and secures the inside diameter in the manner described. As a result of the sleeve (V) the seal rings (V) can easily be stored as bulk materials without having to be afraid of damage 30 to the seal ring (V).

The seal ring (V) is pressed into the installation cavity together with the sleeve (V) with the aid of the insertion tool which during the insertion process lies against the circular flange (V), whereby the seal ring (V) can be installed effortlessly. Then the sleeve (V) can be withdrawn without difficulty or pushed off the shaft and then reused.

In the unit (V', V') according to fig. 3 the seal ring (V') is designed to be similar to that in the design example according to fig. 2. On the base side it has a recess in the form of a shoulder (21) into which the circular flange (V') of the mounting sleeve (V') protrudes.

The circular flange (6") has a lower radial length than the seal ring (1"). In the design example the circular flange (6").is only approximately half as wide as the seal ring (I"). At the changeover from the circular flange (6") to the shell (8") the mounting sleeve (7") has the changeover section (19") which is approximately semicircular in its cross-section and which forms the circular groove (19a"). In addition, the circular flange (6") is provided with a further circular groove shaped recess (22) close to its free end on the side away from the seal ring (1").

The seal lip (4a") is much shorter than the lip (4al) in fig. 2 and is positioned at a distance from the outer surface (20") of the shell (8") of the mounting sleeve (711).

At its end away from the circular flange (6") the mounting sleeve (7") is provided with a circular shoulder (11") which points radially inwards and whose radial width is several times larger than the corresponding width of the circular shoulder (11) according to fig. 1.

Z:

The radial inner edge (23) of the circular shoulder (1111) is curved at a right angle axially inwards and lies coaxial to the shell (8"). It is approximately twice as long as the edge (23) which limits an insertion opening (1811) for a crankshaft (not shown). With the cylindrical edge the mounting sleeve (V1) together with the seal ring (V') fitted can be initially centred upon the crankshaft. The inside diameter of the cylindrical edge (23) in this case corresponds to the outside diameter of the relevant section of the crankshaft.

The seal rings described above are pre-assembled with the mounting sleeves to form a unit and are stored in this way. The mounting sleeve protects the seal ring against contamination, against any change in the seal lip diameter and against damage and other disruptive factors during storage, transportation and installation. After installation, the mounting sleeve is removed by hand, whereby the seal ring takes up its installed position.

In the seal rings (1, V, V') described above, the seal lip (4, 4a, 4', 4a, 4a") consists of an elastomeric or plastomeric material, preferably polytetrafluoroethylene. The mounting sleeve (7, V, V') is preferably made of plastic. This makes the unit environmentally friendly so that upon industrial use the mounting sleeve matched to the relevant application by the manufacturer of the seal ring can be used several times. Finally the connection of the seal ring to the mounting sleeve means that the seal ring can be fitted easily and quickly without mistakes.

(See figs. 1, 2 and 3).

Claims (1)

1. Claims

   1.Seal ring with at least one seal lip which in particular consists of polytetrafluoroethylene, characterised in that the seal lip (4, 4', 4a', V') is in contact with a protection part (7, V, V') when the unit is not fitted and can be pressed onto the seal ring (1, 11, V').

   2.Seal ring according to claim 1, characterised in that the protection part (7, V, V') has a shoulder (6, 6', 6"). against which the seal ring (1, 11, 111) lies.

   3.Seal ring according to claim 1 or 2, characterised in that the protection part (7, V, V') has a cylindrical shell (8, E', 8") on whose outer surface (20, 2011) the seal ring (1, V, V) lies with its seal lip (4, 4', 4a).

   4.Seal ring according to one of claims 1 to 3, characterised in that the protection part (7, 71, 7") has a circular shoulder (11', 11") which protrudes approximately radially inwards, with an insertion opening (18, 1811).

   is S.Seal ring according to one of claims 1 to 4, characterised in that the insertion opening (1811) is formed by a cylindrical edge (23) connecting to the circular shoulder 6.Seal ring according to claim 5, characterised in that the edge (23) lies coaxially to the shell (8").

   Seal ring according to one of claims 1 to 6, characterised in that the shoulder (6, 6', 6") stretches radially outwards and in the direction opposite to that of the circular shoulder (11, 11', 11").

   8. Seal ring according to one of claims 1 to 7, characterised in that the shell (8, E") changes into a curved section (19, 19") at the shoulder (C, 611).

   9,Seal ring according to one of claims 1 to 8, characterised in that a section (14) of the shell which points away from the circular shoulder (11) protrudes axially over the shoulder (6).

   10..Seal ring according to claim 9, characterised in that the shell section (14) which protrudes over the shoulder (6) decreases in the outward direction.

   11.Seal ring according to claim 9 or 10, characterised in that the shell section (14) is preferably rippled on the outside (15) at its end.

   12.Seal ring according to one of claims 1 to 11, characterised in that the protecting part (7, V, V') is a mounting sleeve upon which the seal ring (1, V, 1") can be fitted.

   13. Seal ring according to one of claims 1 to 12, characterised in that the outside diameter of the protecting part (7, 71, 711) in the area of the seal lip (49 4') is lower than the inside diameter of the seal lip when installed.

   1 14. A seal ring substantially as hereinbefore described with reference to and as illustrated in Figs. 1, 2, or 3.

   published 1990 atThe Patent Office. State House,6671 I-IighHolborn. LondonWC1R4TP. Further copiesmaybe obtainedfrom The Patent Office-