CA2089460A1

CA2089460A1 - Self-locking metal cap and plastic bearing

Info

Publication number: CA2089460A1
Application number: CA002089460A
Authority: CA
Inventors: Michael D. Dierks; Ronald J. Jurgenson
Original assignee: Dana Inc
Current assignee: Dana Inc
Priority date: 1992-04-02
Filing date: 1993-02-12
Publication date: 1993-10-03
Also published as: JPH0626527A; FR2689581A1; BR9300617A; DE4310348A1; GB9306389D0; MX9301853A; AU3567093A; KR930021968A; GB2265688A

Abstract

ABSTRACT OF THE DISCLOSURE
A self-locking metal cap and plastic bearing cup assembly is adapted to be mounted over the end of a journal cross trunnion and secured in a bore of the yoke of a universal joint member. The assembly includes a metal cap having an open end, and a monolithic plastic bearing cup fixedly mounted within the metal cap. The metal cap is provided with a plurality of resilient, outwardly extending tabs or detents formed integrally about the open end of the metal cap and adapted to retain the metal cap within a bore after insertion therein. The plastic bearing cup has an open end, an integral lip seal formed about the inner circumference of the open end, at least one radially extending lubrication groove formed in its inner end surface, and at least one axially extending lubrication groove formed in its inner side wall surface.

Description

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TITLE
SELF-LOCKING METAL CAP AND PLASTIC BEARING
BACKGROUND OF THE INVENTION
1. Field of the Invention The invention relates to bearing cups for the ends of universal joint trunnions and, more particularly, to self-locking metal bearing cap and plastic bearing assemblies which immediately retain the journal cross within the yokes of a universal joint.

2. Summary of Related Art Universal joints are well known devices employed for interconnecting two members or shafts adapted to rotate about respective non-aligned and/or angularly adjustable axes of rotation. Universal joints of this type are widely used in the steering mechanism of vehicles.
Typically, such universal joints include a journal cross formed by a central body portion having four outwardly extending and circumferentially equally spaced trunnions.
The trunnions are coplanar and are arranged in opposed, axially aligned pairs disposed at right angles relative to one another. A bearing cup is rotatably mounted over the end of each of the trunnions, and each of the two opposed pairs of bearing cups is secured within a yoke. The yokes are respectively secured to the rotatable members to provide the universal joint con~ection therebetween.
Generally, the peripheral outer surface of the trunnion and the inner wall of t-le associated bearing cup are spaced from each other and an annulus of needle bearings is disposed within this space. The needle bearings rollingly engage the bearing wall or race and the trunnion to provide substantially frictionless rotation therebetween. A separate seal comprised of a ring of a resilient elastomeric material is required to seal the opening which exists between the open end of the bearing h ~ 0 cup and the trunnion. This separate seal is generally mounted on the bearing cup at the time of its assembly.
When installing universal joints of this type, the following assembiy process is frequently employed. A pair of opposed trunnions on the journal cross are positioned within the pair of bores formed in the arms of a yoke. A
bearing cup is inserted axially through one of the bores on the yoke, with the open end of the bearing cup receiving the end of the associated trunnion. A snap ring is then mounted within the bore behind the closed end of the bearing cup to prevent radial outward movement of the bearing cup away from the trunnion. Another bearing cup is inserted through the bore in the opposite arm of the yoke and similarly secured in position by a snap ring. A
yoke is then mounted on the remaining pair of opposed trunnions in a like manner.

SUMMARY OF ~HE INVENTION
The present invention relates to a self-locking metal 20 cap for a bearing race which is adapted to receive a `
journal cross trunnion and be secured within a bore of the yoke of a universal joint assembly. A metal bearing cap having an open end, and adapted to carry a bearing race in its interior, includes a plurality of resilient, outwardly extending tabs or detents formed integrally with and spaced around the metal cap inwardly from its open end.
These tabs immediately lock upon insertion to retain the bearing cup within a bore of the yoke after insertion therein. This novel construction eliminates the need for a snap ring, an associated snap ring groove, and the additional assembly required therefor.

4 ~ 0 A plastic bearing is preferably mounted within the self-locking metal cap. The plastic bearing comprises a monolithic open-ended plastic bearing cup and an integral lip seal formed about the inner circumference of the open end of the plastic bearing cup, which obviates the need for a separate seal. At least one radial groove and at least one axial groove are formed in the inner surface of the bearing cup for lubrication purposes.

BRIEF DESCRIPTION OF THE DRAWINGS
The above, as well as other advantages of the present invention, will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment when considered in the light of the accompanying drawings in which:
Fig. 1 is a longitudinal elevational view, shown partially in longitudinal section, of the assembly of one o~ the rotational mem,bers of a universal joint including self-locking metal cap and plastic bearing assemblies in accordance with the present invention:
Fig. 2 is an enlarged sectional view of a self-locking metal cap and bearing race shown in Figure l; and Fig. 3 is a plan view taken substantially along line 3-3 of Fig. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, there is illustrated generally at 8 in Figure 1 a portion of a universal joint assembly including a yoke 10 having a pair of arms 12 and 14. A journal cross 16 is mounted between the arms 12, 14 of the yoke 10 via bearing cup assemblies 18 received in bores 19 in the arms 12, 14. The journal cross 16 includes a central body portion 20 having four outwardly exl:ending and circumferentially equally spaced trunnions 22 The trunnions 22 are disposed in a single plane at ri~ht angles relative to one another. A bearing cup assembly 18 is rotatably mounted over the end of each of the trunnions 22, and each of the opposed pair of bearing cup assemblies 18 is secured to the yoke 10 within bores 19 formed in the arms 12, 14 thereof. A pair of the yokes 10 are secured each to one of a pair of rotatable members (not shown) to provide a universal joint connection therebetween.
The bearing cup assembly 18 of the present invention, as best seen in Figure 2, is comprised of a self-locking metal cap 24 within which is seated a bearing cup 26 of a suitable material as will be hereinafter discussed. The metal cap 24 is provided with an open end and is adapted to receive a suitable bearing device for carrying the end of the trunnion 22 as part of a universal ~oint assembly.
The bearing device may be of any suitable type, such as the annulus of needle bearings which is typically used in universal joint bearing cups. Preferably, however, the bearing device is a plastic bearing cup in accordance with another aspect of the present invention, as is described in detail hereinafter.
The metal cap 24 is further provided with a plurality of resilient, outwardly extending tabs 32 formed integrally as by being struck from the circumferential wall of the cap. The tabs 32 function to securely retain the metal cap 24 within the bore 19 in the yoke arms 12 or 14 once the metal cap 24 has been inserted through the bore 19. The tabs 32 are formed to slope outwardly from the wall of the metal cap 24 and away from the open end - . - ., ~

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thereof. Thus, as the open end of the metal cap 24 is inserted into the associated bore, and since the outer diameter of the metal cap 24 is substantially equal to the diameter of the bore, the resilient tabs 32 are deflected inwardly to permit insertion of the metal cap 24 through the bore 19. Once the distal ends of the tabs 32 pass completely through the bore 19, the tabs 32 return to their outwardly extending position so that the distal ends of the tabs 32 engage the inner surface of the yoke arm 12 or 14. The tabs 32 thereby provide immediate and automatic locking of the bearing cup assembly 18 upon insertion within the bore 19 of the yoke arm 12 or 14.
To assure proper alignment of the metal cap 24 within the bore of a yoke arm 12 or 14, at least three tabs 32 must be formed in the metal cap. Preferably, four such tabs 32 are formed, equally spaced around the circumference of the metal cap. The tabs 32 may be formed in any suitable shapq and by any suitable method and, as indicated above, are preferably formed by striking sections from the wall of the metal cap 24.
In the preferred embodiment, the metal cap 24 retains a plastic bearing cup 26. The bearing cup 26 is formed as a one-piece member having an open end, and an integral lip seal 28 formed about the inner circumference of the open end. The bearing cup 26 is fixedly mounted within the metal cap 24 in any suitable manner, such as by press fitting or by means of an adhesive. Suitable adhesive materials include epoxy resin adhesives. The plastic bearing cup 26 is provided with a chamfered edge 34 at the outer circumference of the closed end thereof to facilitate assembly within the metal cap 24. The metal cap 24 strengthens and reinforces the plastic bearing cup , : . . .. . . . .. ~ . .

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26, and retains it in proper alignment with respect to the trunnion 22 and the yoke arms 12 and 14.
The inner diameter of the bearing cup 26 is substantially equal to or slightly smaller than the outer diameter of the trunnion 22, so that the bearing cup 26 may be snugly mounted on the trunnion 22 as by a light press fit. As seen in Figure 1, the integral lip seal 28 extends outwardly beyond the end surface of the bearing cup 26 and is adapted to sealingly engage a shoulder 30 formed on the trunnion 22. The integral lip seal 28 thereby provides a seal to prevent the loss of lubricant from the interior of the bearing cup 26, as well as to prevent the introduction of foreign material into the bearing cup 26. By integrally moldiny the lip seal 28 with the bearing cup 26, the need for a separate seal member, and the time and effort expended on assembly of the same, is eliminated.
The plastic bea~ing cup 26 is furthèr formed in its inner surface with one or more elongate grooves extending radially along the end wall and axially along the si~e wall of the bearing cup 26 for containing and distributing lubricant at the interface between the bearing cup 26 and the trunnion 22. To this end, an axial groove 36 should be positioned so as to communicate with an associated ,radial groove 38. In a preferred embodiment, as illustrated in Fig. 3, the plastic bearing cup 26 is provided with three circumferentially equally spaced axial grooves 36 each in communication with an associated radial groove 38, the three grooves 38 radiating from an intersection at approximately the center of the closed end of the bearing cup 26.

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The plastic bearing cup may be formed of any suitable plastic material. It has been found, by way of example, that thirty (30) percent glass-filled nylon 6,6 as well as thirty (30) percent glass-filled nylon 4,6 are materials well-suited for the bearing cup.
When assembling universal joints of the type including the self-locking metal cap and plastic bearing cup assembly 18 in accordance with the present invention, a pair of opposed trunnions 22 on the journal cross 16 are positioned within the pair of bores formed in the arms 12 and 14 of a yoke lO. The grooves 36 and 38 in the inner surface of the plastic bearing cup 26 are filled with lubricant, and the open end of the bearing cup assembly 18 is inserted through one of the bores 19 of the yoke 10, with the open end of the plastic bearing cup 26 receiving the end of the associated trunnion 22 as by means of a light press fit. When the tabs 32 formed in the metal cap 24 pass completely t~rough the bore 19, they return to their outwardly extending position so that the distal ends thereof engage the inner surface of the yoke arm 14. The cap 24 thus provides immediate and automatic locking of the bearing cup assembly 18 upon insertion within the bore 19 of the yoke arm 14. A second bearing cup assembly 18 is inserted through the bore in the opposite arm of the yoke 10 in a like manner, and similarly secured in position.
In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment.
However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.

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Claims

1. A self-locking metal cap for securing a bearing adapted to carry the end of a journal cross trunnion within a bore of the yoke of a universal joint member, comprising:
a metal cap having an open end, and adapted to carry a bearing in its interior; and a plurality of resilient, outwardly extending tabs formed integrally with and disposed about the open end of said metal cap, said tabs adapted to retain said metal cap within a bore after insertion therein.

2. A self-locking metal cap for a bearing as defined in claim 1, wherein each of said tabs extends outwardly and away from the open end of said metal cap, whereby each of said tabs will deflect inwardly during insertion of the cap through a bore formed in a yoke arm and return to its outwardly extended position upon complete insertion of said cap.

3. A self-locking metal cap for a bearing as defined in claim 1, wherein said cap includes a peripheral side wall and said tabs comprise portions struck outwardly from said side wall.

4. A self-locking metal cap for a bearing as defined in claim 1, wherein said metal cap includes at least three tabs.

5. A self-locking metal cap for a bearing as defined in claim 4, wherein said metal cap includes four tabs.

6. A self-locking metal cap for a bearing as defined in claim 4, wherein said tabs are substantially equally spaced circumferentially around said cap.

7. A self-locking metal cap for a bearing as defined in claim 5, wherein said tabs are substantially equally spaced circumferentially around said cap.

8. A self-locking metal cap for a bearing as defined in claim 1, further comprising a plastic bearing mounted within said metal cap.

9. A plastic bearing adapted to be mounted over the end of a journal cross trunnion and secured within a bore of the yoke of a universal joint member, comprising:
a monolithic plastic bearing cup including a circumferential side wall and an end wall, and having an open end;
an integral lip seal formed about the inner circumference of the open end of the sidewall of the plastic bearing cup;
at least one radially extending groove formed in the inner surface of the end wall of said bearing cup; and at least one axially extending groove formed in the inner surface of the sidewall of said bearing cup.

10. A plastic bearing as defined in claim 9, wherein each said radially extending groove is positioned so as to be in communication with an associated axially extending groove.

11. A plastic bearing as defined in claim 10, including at least three radially extending grooves and at least three axially extending grooves.

12. A plastic bearing as defined in claim 10, wherein said radially extending grooves are substantially equally spaced circumferentially from one another.

13. A self-locking metal cap and plastic bearing cup assembly adapted to be mounted over the end of a journal cross trunnion and secured within a bore of the yoke of a universal joint member, comprising:
a metal cap having a circumferential side wall, an end wall and an open end, and adapted to carry a bearing within its interior;
a plurality of resilient, outwardly extending tabs formed integrally with said side wall adjacent the open end of said bearing cap, said tabs being adapted to retain said bearing cap within the bore after insertion of said assembly therein; and a monolithic plastic bearing cup fixedly mounted within said metal cap, said plastic bearing cup having a circumferential side wall, an end wall and an open end, an integral lip seal formed about the inner circumference of the bearing cup side wall at the open end thereof, at least one radially extending groove formed in inner surface of the bearing cup end wall, and at least one axially extending groove formed in the inner surface of the bearing cup side wall.