Metal working – Method of mechanical manufacture – Process for making bearing or component thereof
Reexamination Certificate
1999-11-18
2002-11-05
Knight, Anthony (Department: 3676)
Metal working
Method of mechanical manufacture
Process for making bearing or component thereof
C029S458000, C029S897200, C029S722000
Reexamination Certificate
active
06473968
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a joint assembly and a method for making a joint assembly, and more particularly to a telescoping joint assembly and a method for making a telescoping joint assembly having a pair of members which telescopingly cooperate to form a relatively tight and reliable joint.
BACKGROUND OF THE INVENTION
Automotive vehicles and other types of assemblies often utilize telescoping type joints and/or joint assemblies to operatively couple selectively rotatable shafts or members in a manner which allows torque or rotational energy to be communicated and/or transmitted by and between the coupled members, while concomitantly allowing the coupled members to independently move axially with respect to each other (e.g., to selectively move “toward and away” from each other).
For example and without limitation, a vehicle steering system or assembly generally includes a steering shaft or column and a telescoping intermediate shaft which is coupled to and transfers torque between a steering column and a steering gear assembly. Particularly, the rotational energy of the steering column is transferred through the telescoping intermediate shaft to the gear assembly and the wheel suspension assembly, thereby allowing the vehicle to be selectively steered.
Typically, the intermediate shaft comprises and/or includes an inner shaft or member and an outer shaft or member which movably and selectively receives and/or “mates” with the inner shaft or member and which cooperates with the inner member to allow the steering column and gear shaft to be “axially compliant” (i.e., to selectively and independently move “toward and away” from each other).
In order to substantially reduce friction and improve the performance, compliance, and efficiency of this intermediate shaft and/or steering shaft assembly (as well as other types of joint assemblies), the inner member is typically coated or lined with a resin, rubber or polymer material, or contains a bearing assembly. The telescoping intermediate shaft compensates for the relative movement between the vehicle body and vehicle frame which occurs as the car is driven and allows at least one of the coupled members, such as the steering column, to substantially and desirably “collapse” in the event of a collision or accident, thereby substantially reducing the probability of injury to the driver. The telescoping shaft may further allow the steering column to be adjusted by the driver in an axial or telescopic manner.
Although this intermediate shaft, as well as other substantially similar types of prior joint assemblies, effectively transmit torque between a pair of coupled members or shafts while concomitantly allowing the coupled members to be axially compliant, they suffer from some drawbacks.
For example and without limitation, these prior joint assemblies are typically relatively loose fitting and do not have a relatively precise fit or “correspondence” between the telescoping members and/or between one or more of the telescoping members and the liner or bearing assembly. Particularly, because the members and the liner/bearing assembly are each formed by separate and independent processes, the manufacturing “tolerance” associated with each of the members and the liner/bearing assembly are additively accumulated or “stacked”, thereby resulting in a relatively “loose” overall tolerance and a relatively imprecise or relatively loose fit. As a result, these prior telescoping joint assemblies suffer from undesirable “slop”, “lash”, vibration, frictional loss, and/or “frictional lock-up”, which require relatively costly and complicated modifications.
Particularly, these undesirable attributes hinder and/or undesirably diminish the sliding engagement between the telescoping members, resulting in an inefficient transmission of torque or rotational energy while concomitantly creating excessive wear and fatigue to and of the telescoping members, thereby causing failure and/or diminished performance (e.g., undesirably allowing vibrational forces and/or other movements/forces to be readily transferred between the coupled components and/or members, such as between the wheel suspension assembly and the steering column).
Efforts to improve these relatively loose joints typically include but are not limited to relatively costly sizing, adjusting, or machining of the respective shafts. Furthermore, in order to obtain a more precise tolerance or fit between the inner and outer members, the members must typically undergo relatively complex and undesirable machining processes after they have been formed and/or after a lining has been applied to the inner and/or outer member. This “post-fabrication” machining undesirably increases the expense, time, and difficulty of the manufacturing process.
There is therefore a need to provide a telescoping joint assembly for coupling two members or shafts which overcomes at least some of the various and previously delineated drawbacks of prior coupling assemblies; which allows torque and rotational energy to be relatively efficiently transmitted between the two coupled members or shafts, while concomitantly allowing each of the members or shafts to be axially compliant; which provides for a substantially “tight” fit between the telescoping members; which substantially eliminates and/or reduces “slop”, lash, frictional loss, and/or “frictional lock-up”; and which substantially eliminates the need for post-fabrication “machining” of the telescoping members.
SUMMARY OF THE INVENTION
It is a first object of the invention to provide a telescoping joint assembly and a method for making a telescoping joint assembly which overcomes some or all of the previously delineated drawbacks of prior telescoping joint assemblies.
It is a second object of the invention to provide a telescoping joint assembly which selectively allows torque and/or rotational energy to be transmitted and/or communicated between two telescoping members, while concomitantly allowing the telescoping members to selectively, independently, and reciprocally move toward and away from each other.
It is a third object of the present invention to provide a telescoping joint assembly which provides for substantially “tight” or precise dimensional fit or correspondence between two operatively assembled telescoping members.
It is a fourth object of the present invention to provide a telescoping joint assembly which substantially eliminates and/or reduces “slop”, “lash”, frictional losses and/or “frictional lock-up”, and which substantially eliminates and/or reduces the amount of vibrational forces transferred between the coupled members.
According to a first aspect of the present invention, a telescoping joint assembly is provided. The telescoping joint assembly includes a first member having an inner cavity; a second member which is selectively and movably disposed within the cavity and which cooperates with the first member to form a gap; a certain amount of a thermoplastic material which is disposed within the gap and which selectively shrinks and solidifies, thereby bonding to the second member and allowing the second member to be slidably disposed within the cavity.
According to a second aspect of the present invention a method for making a telescoping joint assembly is provided. The method includes the steps of providing a first member having a cavity of a first shape; providing a second member adapted to be inserted within the cavity; placing an amount of thermoplastic material within the cavity; heating the cavity effective to liquefy the thermoplastic material; heating the second member; inserting the heated second member within the cavity, effective to cause the thermoplastic material to be distributed within the cavity and around the second member; cooling the first member effective to solidify the material, thereby bonding the material onto the second member and creating a telescoping joint assembly.
These and other objects, aspects, features, and advantages of the present invention will become apparent from a consideration of the follo
Johnston Alan C.
Mastrofrancesco Luigi
Ford Global Tech, Inc.
Ford Global Tech., Inc.
Hutton Doug
Knight Anthony
LandOfFree
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