JPS6121865B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates generally to seals, and more particularly to special
Concerning end seals suitable for harsh applications.

One application that has been proposed for a number of seals is for so-called track pins used in crawler tractor equipment. Crawler tractors typically include a pair of tracks, each track consisting of both an inner and outer chain of track links. A large number of links, typically 30 to 40 links, are assembled into an endless chain,
Two such chains span the front idler roller and rear sprocket drive, as well as a number of suspended track rollers and track-carrying idler rollers. Both the inner and outer links of each chain are retained by track pins and bushings passing through openings at each end of the track links. A track shoe or grouser plate spans laterally between each link of the inner and outer chains. These shoes, or plates, form a surface that acts on the ground and ultimately supports the traction force of the vehicle. Each left and right track of the vehicle includes a plurality of plates that extend between the links of the inner chain and connect the links to the links of the outer chain.

This type of rail vehicle is operated under particularly harsh conditions, i.e.
Because they are designed for use in mud, sand, gravel, ice, snow, and rock, and because the raceway is the part that most directly and frequently encounters these harsh conditions, the raceway pins and their bushings are susceptible to rapid wear. receive.

An effective raceway pin seal must be able to accommodate relatively large axial dimensional changes and associated wear. Such seals must have adequate axial elasticity to provide sufficient initial axial force to exclude water and gravel and retain lubricant even under minimal load conditions.

The seals of the present invention have most or all of the advantages of prior art seals and have lower initial cost. This seal uses a different structure and materials than those of the prior art, and also has new operating characteristics and advantages.

The present invention provides an annular primary seal member having an axial flange portion extending substantially axially and a radial flange portion extending substantially radially from an axial front end of the axial flange portion, the axial flange portion having an inner diameter. the radial flange portion has a front portion and a rear portion that extend substantially in the radial direction; A generally annular secondary seal member is provided having a portion for sealingly engaging the mating surface, an inner diameter surface and an outer diameter surface extending substantially in the axial direction, and a front portion and a rear portion, the front portion and the rear portion having a substantially annular shape. The rear portion slopes forward and inwardly to have a generally parallelogram cross-section when the secondary seal member is in an unloaded condition, and the inner diameter of the secondary seal member extends in use to the axial flange of said primary seal member. at least a portion of the forward portion of the secondary seal member engages at least a portion of the rear portion of the primary seal member, the primary seal member being constructed from a first rigid elastomeric material. and the secondary seal member is made of a second elastomeric material less rigid than the first elastomeric material, and the axial flange portion of the primary seal member is compressed on its inner diameter by a portion of the member sealed thereby during use. It is characterized by being configured to be supported.

The seal of the present invention is provided with a primary seal member and a secondary seal member, and the primary seal member includes an axial flange extending substantially in the axial direction and a radial direction extending substantially radially from the axial front end of the axial flange. The secondary seal member is supported by the axial flange and the radial flange. And when the front part of the radial flange is pressed against the opposite surface to the front part,
It has a portion for sealing engagement with the mating surface, thereby sealing one of the spaces to be sealed.

The secondary seal member has an inner diameter surface and an outer diameter surface extending substantially axially, and has a front portion and a rear portion, the front portion and the rear portion being substantially parallel when the secondary seal member is in an unloaded state. It slopes forward and inward to have a quadrilateral cross section. Moreover,
In use, the inner diameter of the secondary seal member is supported on the outer diameter surface of the axial flange of the primary seal member, with at least a portion of the forward portion of the secondary seal member engaging at least a portion of the rear portion of the primary seal member. match.
The primary seal member and the secondary seal member are as described above, and the functions of both members will be explained next. For explanation of this effect, please refer to FIGS. 7 and 8. FIG. 7 shows the primary seal member and the secondary seal member in an assembled state before installation. FIG. 8 shows the configuration of the component when the secondary seal member is slightly deformed and installed under a moderate load. That is, when the secondary seal member is installed in use and compressed in the axial direction, the secondary seal member has a substantially parallelogram cross section, so that the inner diameter side of the front part and the rear part of the secondary seal member have a substantially parallelogram cross section. When pressed on the outer diameter side and further compressed in this state, the secondary seal member is distorted, slightly reducing the angle Θ,
Its side walls 70, 72 tend to expand and become flatter. That is, its axial length becomes shorter. This increases the radial compressive load on the primary seal member, causing it to be tightly gripped by the secondary seal member.
Additionally, the primary seal member is made from a first elastomeric material having a stiffness, and the secondary seal member is made from a second elastomeric material that is less stiff than the first elastomeric material. can move without creating excessive or insufficient axial loads.

By way of illustration, in FIG.

The track pin 14 has an end cap 16 that is mounted along an interface 18 between its inner diameter and the outer diameter of the track pin 14, so that these parts do not move relative to each other. The end cap 16 typically constitutes the front portion of a single track link, and the rear portion of the same link is press fit into a bushing that is rotatable with respect to the next track pin.

Link 22, of which the corresponding end of the preceding track link is shown in FIG. 1, has an open wall portion 24 that accommodates the outer diameter of track pin bushing 28. An operating gap 30 exists between the inner diameter 32 of the track pin bushing 28 and the outer diameter 34 of the track pin 14;
The centerline of the track pin is indicated at 20.

Link 22 and track pin bushing 28 are press-fitted and therefore move integrally with respect to track pin 14.

The seal is housed in a cavity 36 in the end cap 16 formed in part by a mating face 38 of the raceway pin bushing 28. Outer surface 4 of spacer ring 42
0 and the radial end wall 44 and axial wall 46 of the end cap 16 form a cavity 36. An annular primary seal member 48 is received within the cavity 36 and includes a slightly sloped end face 50 terminating in the edge 52, with a peripheral edge 54 (FIG. 2) located radially inwardly of the edge 52 forming the primary seal member. To form a sealing area or surface that actually engages said mating surface 38 on the track pin bushing 28. The inner diameter of the primary seal member 48 has a plurality of serrations 56 (FIG. 3,
Fig. 4) (hereinafter also referred to as teeth). Generally axially and radially extending annular surfaces 62, 64 receiving secondary seal members 60 are connected to primary seal member 48.
is formed.

The secondary seal member 60 of elastomeric material has a generally parallelogram-shaped body in cross-section with inner and outer axial surfaces 66, 68 and slightly inclined forward and rearward surfaces 70, 72. A flange 74 extending outwardly and upwardly of the cross-section is formed around the radially outer leading edge of the secondary seal member 60. This flange 74 is radially restricted and deformed as shown when the seal is installed (FIG. 1).

The annular secondary seal member 60 is preferably a relatively flexible synthetic rubber material, such as nitrile ("Buna N") rubber, which is well resistant to temperature changes and has a hardness of about 50-60 on the "A" durometer. made from. Other rubber compositions are also suitable. The annular primary seal member 48 is preferably made from a contact wear resistant elastomer such as polyurethane rubber, e.g. a 90-95 Durometer hardness material. An example of such a composition is poly(1,4
is the reaction product of a stoichiometric excess of the 2,4- and 2,6-isomers of tolylene diisocyanate with a polyether glycol, such as (oxybutylene) glycol, and has a molecular weight of about 1500 to about
There are 3000 rubber forming prepolymers. This prepolymer is then cured with a reactive diamine such as methylene-bis-orthochloroaniline. The cured elastomer has a durometer hardness of 90-95 and a specific gravity of approximately 1.16. Other compositions can also be used.

During installation, the secondary seal member 60 is slid over the primary seal member 48 to seal the opposing surfaces 62, 66 of the primary and secondary seal members with a moderate degree of fit that requires a slight extension of the secondary seal member 60. engage each other. These two members are then inserted into the cavity 36 so that the serrations 56 forming the axial grooves 76 are slightly spaced from or slightly engaged with the outer diameter 40 of the spacer 42. Flange 74 engages inner surface 46 of secondary seal member 60 when it is initially installed within counterbore 46 . Secondary seal member 60
is pushed fully into the counterbore until side 72 meets end wall 44 of cavity 36.

Rounded portion 78 of secondary seal member 60 engages radius 80 of end cap 16. When no axial load is applied, the outer diameter surface of the secondary seal member 60 is slightly spaced from or lightly engaged with the counterbore surface 46. Flange 74 centers secondary seal member 60 within the cavity. The edge 52 of the primary seal member 48 contacts the end wall or mating surface 38 of the bushing 28, slightly distorting the sides 54 of the primary seal member 48 and creating a seal surface 54 of measurable width. The extent to which bushing 28 can move to apply an axial load to the seal structure is determined by the axial width of spacer 42. When the end face 82 of the spacer engages the mating face 38 of the bush 28, the assembly of the end cap 16, track pin 14 and spacer 42, which are assembled in the direction of the bush 28, is completed.

When the above seal unit is compressed in the axial direction,
The elastic secondary seal member 60 is distorted. When the secondary seal member 60 is axially compressed, its side wall 7
0.72 (FIG. 2) will try to expand and become more flattened and less frustoconical. That is, its axial length becomes shorter and its cone angle becomes flatter. This increases the radial compressive load on the primary seal member 48 and causes the primary seal member 48 to be gripped more tightly by the secondary seal member 60. At this time, the secondary seal member 60 can transmit a considerable amount of torque.

According to this embodiment, the inner diameter surface of the primary seal member 48 includes a metal surface, ie, a serration 56 that engages and rests on the spacer 42. Before installation, the teeth 56 are sharp (FIG. 3), but the radial compressive load causes the teeth 56 to become distorted as shown in FIG. However, the groove 76 still remains open and can retain a significant amount of oil within the sealed area. The total volume occupied by groove 76 and the volume of cavity 84 can accommodate oil, as can the gap area 30 between track pin 14 and bush 28.

A primary seal member 48 made of tough rubber is supported by spacers 42. The tooth grooves 76 make available any oil retained within the track pin structure. Secondary seal member 60 is flexible and has a low axial modulus so that primary seal member 48 can move without creating excessive or insufficient axial loads. If the elasticity is too high, the seal will wear out quickly. If the force is too low, the sealing action will be incomplete. The secondary seal member 60 is a flattened frusto-conical ring having a generally parallelogram cross-section. Other equivalent shapes work well (section 5a
(see Figure 5b). Rubber is substantially incompressible when completely surrounded. The secondary seal member 60 is distorted under load, causing the primary seal member 48 during use to become distorted.
axial sealing load and radial compression load.

In the present invention, the primary sealing member 48 is rigid but elastomeric, so that the portion of the secondary sealing member 60 located behind the intended sealing area 54, even if the secondary sealing member 60 Even when relaxed, there should be contact with the fillet or wedge of rubber from the secondary seal member 60.

In use, the spacer 42 is attached to the button 28.
axially inward movement of the raceway pin 1.
A corresponding spacer 42 at the opposite end of 4 prevents axial movement in the opposite direction. The radial force establishes a positive mechanical relationship between the end cap 16 and the primary seal member 48. Primary seal member 48
is supported by the lubricated surface 40 of the spacer 42.
The sides 50 of the primary seal member 48 are slightly angled so that the entire surface does not contact the surface 38.

FIG. 5a shows an annular primary seal member 4 having an inclined seating surface 100 facing radially outward and rearward.
8a is shown. The secondary seal member 60a is in the form of an O-ring when relaxed, and is slightly toroidal or slightly flattened when in use. A radially inwardly and forwardly facing seat surface 102 is formed on the end cap 16a.

The two opposing surfaces 100, 102 form frusto-conical slopes, and the O-ring shaped secondary sealing member 60a
moves on said slope when the ring is subjected to radial and axial loads. Each seal member 48a, 60
a functions in substantially the same manner as the corresponding parts of Figures 1-4, and the materials from which these parts are made can also be the same.

FIG. 5b shows the primary seal member 48b and the first seal member 48b.
FIG. 2 shows a secondary seal member 60b that is slightly different from the secondary seal member 60 of FIG. A plurality of deformable mounting spikes or returns 108 are provided to facilitate proper initial seating or positioning of the secondary seal member 60b. In use,
The cross section of the secondary seal member 60b is slightly deformed, and the secondary seal member 60b operates in substantially the same manner as the secondary seal member 60 of FIGS. 1-4.

Figure 5c shows an annular secondary seal member 60c including small feet 110, 112 at its radially inner and outer ends, respectively. When the secondary seal member 60c is relaxed, the legs 110, 112 and the secondary seal member 60
There appear to be small notches 114, 116 in the secondary seal member 60c between it and the remainder of the sealing member 60c. When loaded axially, the secondary seal member 60c distorts and closes most or all of the notches 114, 116, causing the legs 110, 112 to close the secondary seal member 60c.
Tightly touch c. The seal shown in Figure 5c operates similarly to the seal of Figures 1-4 and is made of the same materials.

Figures 6-9 show modified forms of the seal of the present invention. FIG. 6 shows the seal installed at a typical prescribed "use interval" and FIG. 7 shows the seal placed in the counterbore just before installation is complete. Figure 8 shows the seal at its maximum "use interval". Figure 9 shows the seal at minimum "use interval", or maximum compression. Raceway pins and similar seals are referred to as having a "service interval" that indicates the degree of axial compression of the seal structure. Maximum “use interval”
occurs when the bottom of the counterbore is axially far removed from the portion of the primary seal member that forms the seal area 54. The minimum distance of use occurs when the seal zone forming portion of the primary seal member is closest to the bottom portion of the counterbore. The prescribed or typical usage interval lies between these extremes, and is the interval desired but not always achieved in practice. Variations in service intervals arise from the service intervals required to permit machine use and from the need for reasonable manufacturing tolerances. The seal is mainly a secondary seal member 6
0 or by compression of the spring member, and more or less
Deflection or compression of portions of the primary seal member 48 accommodates variations in usage intervals.

If the seal is operated beyond the maximum service interval, it will not be compressed sufficiently to axially load the seal area and will fail to seal. When the seal is compressed beyond the minimum allowable service interval, the compression of the secondary seal member is at its maximum, and such compression creates a force that forces the film of lubricant from between the parts, causing the seal to become damaged due to excessive friction and high temperatures. Breaks down rapidly.

6-9 includes a bush 28d having a spacer 42d, an end contact portion 38d, and a counterbore having a radial wall 44d and an axial wall 46d. A sealing cavity 36d is formed by these three surfaces and the spacer 42d.

Primary seal member 48d and secondary seal member 6
A sealing structure 10d consisting of 0d is positioned within the seal receiving opening 36d, and the outer circumferential surface 68d and inner circumferential surface 66d of the primary sealing member 60d are parallel to each other, but from the counterbore surface 46d, and the outer circumferential surface of the primary sealing member 48d. Gap "X" from 62d, respectively.
They are separated by "Y".

These “X” and “Y” spacings are typically 25.4mm
It is on the order of several thousandths of . In one case,
Gap "Y" is substantially zero or a slight interference fit, and spacing "X" is 0.020-0.060 inches. In such a case, the inner peripheral surface 66d and the outer peripheral surface 62
The interference fit between the primary seal member 48d and the secondary seal member 60d allows the primary seal member 48d and the secondary seal member 60d to be handled as one unit. When the seal is in this position,
The molded portions of each member 60d, 48d relax and the end face 38d of the bushing 28d separates from the seal area or edge 52d of the primary seal member 48d. In this condition, there is an angle Θ between the vertical plane of the primary seal member 48d and the frustoconical surface of the secondary seal member 60d. Such angle Θ is, for example, 30°.

Installed on bush 28d and track link part 22
d towards the cap 16d (FIG. 8). At this time, the bush 28d slides along the track pin 14d. Primary seal member 48
When the edge 52d of the bushing 28d engages the end face 38d of the bushing 28d and is thereby moved in the axial direction, the secondary sealing member 60d is moved into a snug seat, with its rounded portion 78d forming a portion 80 of the counterbore 36d.
d. Further compression creates an axial sealing load by straining the secondary seal member 60d into compression and slightly reducing the angle Θ, for example to 20° or 25°. When the secondary seal member 60d is in the position shown in FIG. 8, the surfaces 70d and 72d are parallel to each other and do not expand or distort to any measurable extent even if they are tilted at an angle Θ.

FIG. 6 shows the seal in a typical or "standard" use position with faces 70d and 72d slightly expanded. FIG. 9 shows a seal with minimum spacing, with both front and rear surfaces 70d, 72d significantly expanded. The leading edge of the primary seal member is comprised of planar portions 200 and 202 in the embodiment of FIGS. 6-9, but portion 200 is sloped rearwardly. The inner planar surface 202 is slightly sloped toward the bottom of the counterbore 46d.

Axial range or spacing in Figures 6-9
H ₁ , H ₂ , H ₃ , H ₄ indicate the meaning of the term usage interval or action interval. Edge 52d of primary seal member 48d
The dimension _H1 from the rear edge 78d of the secondary seal member 60d is the maximum distance (FIG. 7). This is the spacing before the unit is installed. H ₂ indicates the maximum attachment interval, which is smaller than before the device. _H3
is subjected to a moderate or intended usage load,
Typical usage or wear intervals. H ₄ is the shortest or minimum mounting distance, which is the distance obtained under the maximum permissible load.

Articulated or two-piece surfaces 200, 20 at the edges of the radial flange of the primary seal member 48d
2 has proven advantageous in use. With this construction, a slightly larger effective angle can be achieved between the counterbore surfaces 50, 38 in the embodiment of FIGS. 1-5. The frusto-conical portion 202 provides a sufficiently sharp angle between the face 200 and the end surface 38d of the bush 28d even when the seal operates in a range of low working distances, including the working distance shown in FIG. A good seal can be formed.

The seals made according to the present invention have a long life and high reliability considering their low cost, and can be used in extremely harsh environments such as track pin seal applications.
In addition to extending the life of the sealed portion, a much quieter orbital chain is obtained than generally available in the past. Several preferred forms of the seal of the present invention have been detailed. Other equivalent forms of such seals are also within the scope of this invention.

The embodiments of the present invention are as follows.

1. An annular primary seal member having an axially extending axial flange portion and a substantially radially extending flange portion, the axial flange having an inner diameter surface and an outer diameter surface, The flange portion has a generally radially extending front portion and a rear portion, the front portion of the radial flange portion being in tight sealing engagement with the mating surface when pressed axially toward the mating surface. has a part,
A generally annular secondary seal member is provided, the secondary seal member having an inner diameter surface and an outer diameter surface as well as a front portion and a rear portion, the front and rear surfaces being substantially parallel when the secondary seal member is under load. Slanting forward and inwardly to have a quadrilateral cross-section, the inner diameter of the secondary sealing member being received in use within the outer diameter of the axial flange portion of the primary sealing member and at least the front surface of the secondary sealing member. a portion engages at least a portion of the rear surface of the primary seal member, the primary seal member is made from a relatively rigid but resilient first elastomeric material, and the secondary seal member is substantially more substantially rigid than the first material. made from a second elastic elastomer material that is less rigid;
The flange portion of the primary seal member has an inner diameter supported by a portion of the element to be sealed during use.

2. The seal unit according to claim 1, wherein the substantially radially extending front surface of the radial flange is slightly inclined forward as it extends in the radial direction.

3. In an unloaded state of the seal, a radially inner portion of the front portion of the secondary seal member extends forward of the remainder of the front portion and is substantially parallel to the rear portion of the radial flange of the primary seal member. The seal unit according to item 1, wherein the seal unit is configured to:

4. A seal unit according to claim 1, including means for defining the inner diameter of the primary seal member at least partially from an oil passage extending axially from the front portion of the radial flange to the rear portion of the axial flange.

5. The inner diameter surface of the axial flange includes a plurality of radially inwardly directed support projections having circumferentially spaced inner ends that engage a portion of the element to be sealed in use. the inner diameter is thereby supported against substantial radial inward movement, and the support protrusion is provided with an axially extending lubricant between the front surface of the radial flange and the rear surface of the axial flange in use. 2. The seal unit according to claim 1, wherein the seal unit is configured to form a passage.

6. The support protrusion is in the form of a serration;
The inner end is an axially extending tooth, said inner end substantially circumferentially engaging said portion of said sealed element due to the radial load imposed on the primary seal member by the secondary seal member. 6. The seal unit according to claim 5, wherein the seal unit is flat.

7. The seal unit according to item 1 above, wherein the first elastomer material comprises a urethane elastomer.

8. The seal unit according to claim 1, wherein the second elastomer material comprises nitrile rubber.

9 The secondary seal member is deformed so that its front and rear surfaces expand outward due to the axial load applied to the seal, and the parallelogram cross section is also distorted, causing the inner diameter surface and outer diameter surface to align in the radial direction. 2. The seal unit according to claim 1, wherein the seal unit is adapted to be moved towards the position.

10 A combination track pin 14 and seal structure including a track pin, a first link portion attached to the track pin, and a second link portion supported for rocking relative to the pin. , a bushing surrounding a portion of the pin and contained within the portion of the second link, the bushing including a radially extending and axially oriented end surface and disposed within the first link; an annular spacer surrounding the pin and extending between an end face of the counterbore and an end face of the bushing, the outer diameter of the spacer, the end face of the bushing, and the counterbore forming a seal receiving cavity; and an end seal unit is disposed within the cavity, the unit including a primary annular seal member having a generally axially extending flange portion, the axial flange having an inner diameter surface and an outer diameter surface, and a radially extending flange portion. The radial flange has a generally radially extending front portion and a rear portion, the front portion of the radial flange being in tight sealing engagement with the mating surface of the bushing when pressed axially toward the mating surface. a flattened, frusto-conical, annular secondary seal member having a generally axially extending inner and outer diameter surface and a front portion and a rear portion; The front and rear surfaces are inclined forwardly and inwardly such that the secondary seal member has a substantially parallelogram cross section in an unloaded state, and the inner diameter of the secondary seal member is equal to the outer diameter of the axial flange portion of the primary seal member. a first elastomer which is housed in a relatively rigid but resilient material such that at least a portion of the front surface of the secondary seal member engages at least a portion of the rear surface of the primary seal member; the secondary seal member is made of an elastomeric material having substantially less stiffness and resiliency than the first material, and the axial flange portion of the primary seal member has an inner diameter reduced by an outer diameter portion of the spacer. A combination raceway pin and seal structure adapted to be supported.

11 The end face of the bushing engages with the spacer, and the secondary seal member deforms under the axial load applied to the primary seal member by the bush end face, causing both the front and rear surfaces of the secondary seal member to expand outward. 11. The combination of claim 10, wherein the parallelogram cross-section is deformed such that its inner and outer diameter surfaces are moved towards a radially aligned position.

12 The front portion of the radial flange portion of the primary sealing ring includes a first surface and a second surface, the first surface being a substantially planar radially extending surface, and the second surface being common to these surfaces. 2. The end seal of claim 1, wherein the end seal is joined along an edge and is frustoconical, the second surface sloping radially outwardly toward the mating surface.

13. The end seal of claim 12, wherein the angle between the first and second portions, measured externally, is about 140° to about 165°.

[Brief explanation of the drawing]

FIG. 1 is a partially broken vertical sectional view showing the raceway pin seal of the present invention in use, and FIG. 2 is a sectional view before installation, showing the axial lubrication passage in the inner diameter of the primary seal member. Figure 3 is 3- in Figure 2.
A partially enlarged fragmentary front view along line 3, Figure 4 is the 1st
An enlarged front view of the seal of FIG. 1 taken along line 4-4 in the figure, FIG. 5a is a vertical cross-sectional view of an example with a modified cross-sectional shape, and FIG. 5b is a vertical cross-sectional view of an example with a further modified cross-sectional shape. 5c is a vertical sectional view of a still modified example; FIG. 6 is a fragmentary vertical sectional view of a seal in a modified form according to the invention, showing the seal in its normal installed and used condition; FIG. 7 is a fragmentary vertical cross-sectional view of the seal just prior to installation, and FIG. 8 is a vertical cross-sectional view of the seal of the present invention, showing the seal in its installed, lightly compressed state in use. 9 is a vertical cross-sectional view of the seal of FIGS. 6-8, showing the seal in a fully compressed state; FIG. 14... Orbit pin, 16... End cap, 28
...Button, 36...Cavity, 42...Spacer, 48...Primary seal member, 56...Teeth, 60
...Secondary seal member.

Claims (1)

[Scope of Claims] 1. An annular primary seal member having an axial flange portion extending substantially in the axial direction and a radial flange portion extending substantially radially from the axial front end of the axial flange portion; The radial flange portion has an inner diameter surface and an outer diameter surface, the radial flange portion has a front portion and a rear portion that extend substantially radially, and the front portion of the radial flange portion extends axially toward the mating surface. a substantially annular secondary sealing member having a portion that engages in tight end face sealing engagement with a mating surface when pressed, and having an inner diameter surface and an outer diameter surface extending substantially in the axial direction, and a front portion and a rear surface portion; The front and rear portions of the secondary seal member are inclined forwardly and inwardly to have a generally parallelogram cross-section when the secondary seal member is in an unloaded condition, and the inner diameter of the secondary seal member is in use, the primary seal member is supported on an outer diameter of the axial flange portion of the primary seal member, and at least a portion of the forward portion of the secondary seal member engages at least a portion of the rear portion of the primary seal member; the axial flange portion of the primary seal member is made from a first elastomeric material having a rigidity, the secondary seal member is made from a second elastomeric material that is substantially less rigid than the first elastomeric material; An end seal configured to be supported on its inner diameter by a portion of the member to be sealed.