KR20010080178A - Seal assembly having a cone spring encapsulated in a load ring - Google Patents

Abstract

The seal assembly 10 with the disc spring fully encapsulated in the load ring 30 supporting the seal member seals the deflection force to ensure positive contact with opposing surfaces of adjacently disposed members 12 and 14 of the joint assembly. It is provided to the elastic seal part of the member 28. The seal assembly 10 requires a minimized counterbore depth in the member on which it is mounted, and does not require any modifications to the base of the dish spring 50 or the counterbore.

Description

Seal assembly with disc spring encapsulated in load ring {SEAL ASSEMBLY HAVING A CONE SPRING ENCAPSULATED IN A LOAD RING}

Various seals have been developed for use in sealing variable spaces between two relatively constant proportions of members. Joints in which this type of motion takes place are found in the track structure of track-type cars such as tractors. For example, US Pat. No. 4,392,657 (July 12, 1983; Disc Spring Load Seal), assigned to Robert D. Roley and assigned to the assignee of the present invention, seals the sealing element of the structure with the opposing surface of the joint assembly. A seal structure with a dish spring pressed against the joint is described. In the Roley seal structure, the disc spring is modified by a plurality of annularly arranged openings disposed within the actual sealing element of the assembly and extending through the spring itself. The sealing element comprising the disc spring is attached to one end of the support spring having an opposite end pressed into an annular groove formed in the radial wall of the counterbore in which the seal assembly is located. The seal assembly described by Roley requires not only a deep groove machined in the flat radial face of the counterbore to support one end of the cantilever spring, but also to support a sealing element with a cantilever spring-supported dish spring. It requires a relatively deep counterbore.

The present invention is designed to overcome the problems described above. It is desirable to provide a seal assembly with a dish spring that is embedded in the load ring to apply a consistent load to the seal element of the seal assembly to provide improved sealing performance. It would also be desirable to provide a seal assembly that allows for a larger engagement area between the member on which the counterbore is formed and the pin pushed into the counterbore by requiring only a relatively shallow counterbore. It is desirable to have a seal assembly that does not require an annular cantilever spring embedded in the groove of the counterbore base.

The present invention relates generally to a seal assembly, and more particularly to a seal assembly having a conical spring encapsulated within a load ring element of the seal assembly.

1 is a radial cross-sectional partial view of a track pin joint with a seal assembly incorporating the present invention.

2 is a partially enlarged cross-sectional view of a seal assembly implementing the present invention.

3 is a three dimensional perspective view of a load ring element of a seal assembly embodying the present invention showing the load ring in its free state prior to assembly to the joint;

According to one aspect of the invention, a seal assembly for sealing a joint between two coaxial mounting members mounted on a pin or an elongated cylindrical member 16 comprises a seal member and a load ring, the two members being pins. It has a variable space that is rotatable relative to one another about its longitudinal axis and extends axially between opposing radial faces of the two members. The seal assembly is mountable in a counterbore provided in one of the two members. The counterbore is formed by a cylindrical peripheral wall and a recessed radial wall extending radially inward from the cylindrical peripheral wall. The seal member element of the seal assembly has a support and an elastic seal. The resilient seal is configured to be in contact with the opposite radial face of the member, unless one of the two members is preselected. The support of the seal member has an elastic seal and a face configured to support a mounting surface spaced apart from the face. The load ring element of the seal assembly has a frusto-conical disc spring fully encapsulated in a plastic annular housing. The annular housing has an outer cylinder wall configured to be forcibly received in the cylindrical peripheral wall of the counterbore formed on the radial face of the preselected member. The load ring also includes a seal member support surface spaced from an outer circumferential wall configured to forcibly contact the mounting surface of the support of the seal member and maintain the seal member in a fixed relationship with the load ring. At least one central portion of the encapsulated truncated conical spring is disposed between the mounting surface of the support cross section of the seal member and the recessed radial wall of the counterbore. The encapsulated disc spring thereby urges the seal member in a direction away from the radial wall of the recessed counterbore and squeezes the elastic seal portion of the seal member against deflected radial faces when the joint is assembled.

Another feature of the seal assembly embodying the present invention is the support cross section of the seal member of the annular ring, between the radially disposed wall portion, the peripherally arranged wall portion and the radially disposed wall portion and the peripherally disposed wall portion. And a mounting surface of a support cross-section having a compound curved surface comprising a concave curve extending to it. The mating seal member support surface of the annular ring of the load ring also includes radially arranged wall portions, peripherally arranged wall portions and convexly curved portions extending between these radially disposed wall portions and peripherally disposed wall portions. It includes a compound curved surface.

Another feature of the seal assembly incorporating the present invention includes a support cross section of a seal member formed from a plastic material such as injection molded polycarbonate. Another feature of the seal assembly includes an elastic seal portion of the seal member formed from a polyurethane material having a Shore D hardness from about 40 to about 50. Another feature of the seal assembly incorporating the present invention includes a plastic annular housing having a built-in disc spring and formed from injection molded polyurethane having a Shore D hardness of about 40 to about 50.

A more complete understanding of the structure and operation of the present invention may be made by reference to the following detailed description in conjunction with the accompanying drawings.

A depicted embodiment of a seal assembly implementing the present invention is shown generally at 10 in FIGS. 1 and 2. The seal assembly 10 advantageously seals the variable space between the first joint member 12 and the second joint member 14 having a variable space therebetween by making relative movements with respect to each other during operation. Used. In the illustrated embodiment, the first joint member 12 constitutes a portion of the first track link, and the second joint member 14 includes a bushing rotatably mounted to the track pin 16 and the second track. It is received in a portion of the link 18. The track pin 16 is press fit into the bore 22 of the first track link 12, thereby preventing relative movement between the first track link 12 and the track pin 16. The first joint member 12 also has a counterbore formed by a cylindrical peripheral wall 24 and a recessed radial wall 26 extending radially inward from the cylindrical peripheral wall 24. . Movement of the first joint member 12 and the second joint member 14 towards each other is limited by the drumstring 20.

The seal assembly 10 includes a seal member 28 and a load ring 30. The seal member 28 has a support 32 and an elastic seal or lip 34. The elastic seal 34 is configured to be in contact with the opposing radial face of the second joint member 14 when the joint is assembled. The support 32 of the seal member 28 has a face 36 configured to support the elastic seal 34 and a mounting surface 38 spaced apart from the face 36.

The elastic seal or lip 34 is advantageously formed from a relatively soft, ductile material having a Shore D hardness of about 40 to about 50, such as polyurethane. The support 32 of the seal member 28 is formed of a relatively harder material, such as injection molded polycarbonate. The elastic seal portion 34 may be pre-molded or insert molded into the support 32, or may be injection molded in two steps with the support 32.

As best shown in FIG. 2, the seal member 28 is an annular ring having a face 36 disposed entirely on one radial face of the ring and a mounting surface 36 disposed entirely on the rear radial face of the ring. Has a shape. Mounting surface 38 extends between radially disposed wall portions 40, peripherally disposed wall portions 42 and these radially disposed wall portions 40 and peripherally disposed wall portions 42. It is formed by a compound curved surface having concave curved portions 44.

It is important that the load ring 30 has a plastic annular housing, or a truncated conical disc spring that is completely encapsulated within the ring 52. Dish springs, often called conical springs or washers, occupy very small spaces and are pressed in such a way that they provide a particularly high modulus of elasticity. The disc spring 50 is deflected transferred to the seal member 30 and then to the elastic seal 34 via the load ring 30 to keep the elastic seal in deflective contact with the opposing surface of the second joint member 14. Provide power. When in the free state, the load ring 30 with the encapsulated disc spring 50 is centered outward so that when it is assembled to the joint assembly the center portion is compressed toward the recessed radial wall 26 of the counterbore. It is displaced. As a result, the compression provides a biasing force that forces the seal member 34 into contact with the radial face of the second joint member 14. The annular plastic housing 52 encapsulating the disc spring 50 is preferably formed from an injection molded polyurethane material having a Shore D hardness from about 40 to about 50. The disc spring is preferably encapsulated in its free state in the plastic housing 52 by insert molding.

The annular plastic ring 52 has an outer cylindrical wall 54 with a diameter slightly larger than the diameter of the cylindrical peripheral wall 24 of the counterbore such that the corresponding peripheral walls 24, 54 are between them. As a result of interference, they are forced to adjoin each other. In the example showing the interference made in a typical track joint, the counterbore resulted in an interference of about 0.75 mm between the outer cylindrical wall 54 of the load ring 30 and the cylindrical circumferential wall 24 of the counterbore. The cylindrical peripheral wall 24 of has a diameter of 92.3 mm and the outer cylindrical wall 54 of the load ring 30 has a diameter of 93.8 mm. This ensures that the seal assembly 10 remains tightly within the counterbore of the first joint member 12.

The load ring 30 also includes a seal member support surface 56 that is shaped to mate with the mounting surface 38 of the seal member 28. In particular, the seal member support surface 56 is spaced apart from the outer cylindrical wall 54 of the load ring 30 and is not only mated with the mounting surface 56 of the support end face 32 of the seal member 28, but also forcibly. It is configured to be adjacent. The seal member support surface 56 of the load ring 30 is arranged in a circumferential direction with the wall portions 58 arranged in the radial direction, the wall portions 60 arranged in the circumferential direction, and the wall portions 58 arranged in these radial directions. It has a compound curved shape that includes convex curved portions 62 extending between the wall portions 60. The seal member support surface 56 is configured to forcibly adjoin the mounting surface 38 of the support 32 of the seal member 28. In the embodiment depicting this typical track joint, the forced adjacency between the corresponding surfaces 56, 58 is the wall ring 42 and the load ring 30 arranged in the circumferential direction of the support 32 of the seal member 28. Is provided by the interference between the wall portions 60 arranged in the circumferential direction of the plastic housing 52. In the illustrated example, the outer diameter of the wall portion 42 disposed in the circumferential direction of the mounting surface 8 has a diameter of about 92.3 mm, and the diameter of the wall portion 60 disposed in the circumferential direction of the seal member support surface 56. Has a diameter of about 93.8 mm, thereby providing about 0.75 mm of interference between the two members. Therefore, the seal member 28 remains fixed and rotates relative to the load ring 30, but is urged outwardly along the axis from the counterbore by the disc spring 50 disposed in the load ring 30. .

The seal assembly 10 embodying the present invention provides an improved seal for variably spaced joint members, as found in track joints. A disc spring encapsulated in the plastic housing 52 forces a force to force the seal member 28 outwardly along the axis from the counterbore of the first joint member 12 such that the plate spring is deflected in contact with the radial face of the second joint member 14. A ring 30 is provided, whereby the resilient seal 34 ensures positive, continuous, deflection adjacent to the opposing face of the second joint member 14.

The seal member 10 provides improved seal performance due to the consistent load provided by the disc spring 50. The pin retaining capability of the link assembly is also improved due to the reduced need for a deep counterbore in the joint member that non-receiving conventional mounting pins. Therefore, the pin holding ability of the first joint member 12 is improved due to the demand for reduced counterbore depth. Advantageously, the reduction in counterbore depth allows for a wider fin mating surface area with the link 12.

Although the present invention is described by the embodiment shown, with a specific structure related to the track pin joint, those skilled in the art will be able to engage the other joint coupling members of the seal member that practiced the present invention without departing from the spirit of the present invention. It will be appreciated that it is applicable to the structure. Such changes fall within the scope of the following claims. Other aspects, features and advantages of the invention may be learned from the above description and drawings in conjunction with the appended claims.

Claims (8)

A seal assembly for sealing a joint between first and second members 12, 14 coaxially mounted to an elongated cylindrical member 16 having a longitudinal axis, the first and second members 12, 14. Is rotatably moved with respect to each other about the longitudinal axis and has a variable space between the axially opposed radial faces of the first and second members 12, 14, and the first and second members ( The radial face of one of the preselected members 12, 14 is a cylindrical peripheral wall 24 and a recessed radial wall 26 extending radially inward from the cylindrical peripheral wall 24. A seal assembly having a counterbore formed by and mountable to the counterbore, the seal assembly comprising: A seal member 28 having a support 32 and an elastic seal 34 and a load ring 30 having a truncated conical disc spring 50 encapsulated completely within the plastic annular ring 52, The elastic seal portion 34 is configured to be disposed in contact with an opposing radial surface of the member, unless one of the first and second members 12 and 14 is selected in advance, and the support portion 32 is the elastic seal portion. Having a surface configured to support 34 and a mounting surface 38 spaced apart from the surface 36, The annular ring 52 has an outer cylindrical wall 54 and an outer cylindrical wall configured to be forcibly received in the cylindrical peripheral wall 24 of the counterbore of the radial face of the preselected members 12, 14. A seal spaced from 54 and configured to forcibly contact the mounting surface 38 of the support 32 of the seal member 28 and to maintain the seal member 28 in a fixed relationship to the load ring 30. Has a member support surface 56, At least a portion of the encapsulated truncated conical spring 50 is recessed radial wall 26 of the counterbore with the mounting surface 38 of the support 32 when the seal assembly is disposed in the counterbore. And the elastic seal 34 of the seal member 28 is not preselected when the joint is assembled, thereby forcing the seal member 28 away from the recessed radial wall 26. And seal against biasing contact with said opposed radial face of (12, 14). 2. The support portion 32 of the seal member 28 is an annular ring, and the mounting surface 38 of the support portion 32 is arranged radially in a wall portion 40, in a circumferential direction. And a concave curved portion (44) extending between the wall portion (42) and the radially disposed wall portion (40) and the circumferentially disposed wall portion (42). 2. The seal member support surface 56 of the annular ring 52 of the load ring 30 comprises a wall portion 58 arranged radially, a wall portion 60 arranged in the circumferential direction and their radius. And a composite curved surface comprising a convex curved portion (62) extending between the wall portion (58) disposed in the direction and the wall portion (60) disposed in the circumferential direction. The seal assembly of claim 1, wherein said support (32) of said seal member is formed of an injection molded polycarbonate material. The seal assembly of claim 1, wherein the resilient seal portion (34) of the seal member (28) is formed of a material having a Shore D hardness of about 40 to about 50. 7. A seal assembly according to claim 6, wherein said material forming said seal member is polyurethane. 2. The seal assembly of claim 1, wherein the plastic annular ring (52) with built-in disc springs is formed of a plastic material having a Shore D hardness of about 40 to about 50. 9. A seal assembly according to claim 8, wherein said material forming said plastic annular ring (52) is an injection molded polyurethane material.