US 7,731,466 B2Granted

Thread profile modification for controlled stiffness

AssigneeGM Global Technology Operations LLC

InventorsDavid H. Shea, Brian K Bartnick

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Abstract

The thread form can provide a controlled thread stiffness which can more evenly distribute loads and can be less sensitive to changes in relative pitch. The controlled stiffness of the thread can provide a desired cantilever bending of the thread under assembled load. The thread form can utilize a traditional thread form at and/or above the pitch diameter, thereby maintaining the area of contact close to that of a standard thread form. Standard gaging implements can be used to ascertain the thread pitch and for quality control. The thread form includes a side extending between the crest and the root. The side has a first portion extending from the crest toward the root and the second portion extending from the first portion toward the root. The first and second portions extend toward the root in different orientations relative to the thread.

Claims15

Dependent claims

A joined assembly comprising:

a first member having a first aperture extending therethrough;
a second member having a second aperture;
and
a bolt extending through said first aperture and at least partially into said second aperture, said bolt having a helically extending external thread thereon, said bolt axially loading said first and second members and retaining said first and second members together, and said thread including:
a crest;
a root;
and
first and second sides opposite one another extending between said crest and said root, each of said first and second sides having a first portion extending from said crest toward said root and a second portion extending from said first portion toward said root, said first and second portions extending toward said root in different orientations relative to said thread,
wherein said first portion of said first side has a flank angle of a first value and said first portion of said second side has a flank angle of a second value less than said first value, each of said first portions extending from outside of a pitch diameter of said thread to inside said pitch diameter.

6 more elements

Dependencies are inferred from the claim text.