Composite wrist pin and process

Claim 2

A composite engine part, comprising: a piston; a connecting rod; a metal sleeve for pivotally receiving and operatively connecting said piston and said connecting rod; an amide-imide resinous polymeric core for positioning within said sleeve; said metal sleeve and polymeric core cooperating with each other to form a wrist pin; said piston, connecting rod, core, and said sleeve maintaining their structural relationship, shape and integrity at engine operating conditions.

Claim 3

A composite engine part in accordance with claim 1 wherein said core is substantially solid.

Claim 4

A composite engine part in accordance with claim 1 wherein said sleeve and core are annular with generally circular cross-sections.

Claim 5

A composite engine part in accordance with claim 1 wherein said core has an outside diameter slightly greater than the inside diameter of said sleeve and said core and said sleeve are in press-fitting engagement with each other.

Claim 6

A composite engine part in accordance with claim 1 including means for fixedly connecting said core and said sleeve.

Claim 7

A composite engine part in accordance with claim 1 wherein said metal comprises aluminum.

Claim 8

A composite engine part in accordance with claim 1 wherein said metal comprises steel.

Claim 9

A composite engine part in accordance with claim 1 wherein said core comprises a reaction product of a trifunctional carboxylic acid compound and at least one diprimary aromatic diamine.

Claim 10

A composite engine part in accordance with claim 8 wherein said core comprises at least one of the following moieties: ##STR8## wherein one carbonyl group is meta to and one carbonyl group is para to each amide group and wherein Z is a trivalent benzene ring or lower-alkyl-substituted trivalent benzene ring, R 1 and R 2 are different and are divalent aromatic hydrocarbon radicals of from 6 to about 10 carbon atoms or two divalent aromatic hydrocarbon radicals of from 6 to about 10 carbon atoms joined directly or by stable linkages selected from the group consisting of --O--, methylene, --CO--, --SO 2 --, and --S-- radicals and wherein said R 1 and R 2 containing units run from about 10 mole percent R 1 containing unit and about 90 mole percent R 2 containing unit to about 90 mole percent R 1 containing unit and about 10 mole percent R 2 containing unit.

Claim 11

A composite engine part in accordance with claim 9 wherein R 1 is ##STR9##

Claim 12

A composite engine part in accordance with claim 9 wherein Z is a trivalent benzene ring, R 1 is ##STR10## R 2 is ##STR11## and wherein the concentration range runs from about 30 mole percent of the R 1 containing units and about 70 mole percent of the R 2 containing units to about 70 mole percent of the R 1 containing units and about 30 mole percent of the R 2 containing units.

Claim 13

A composite engine part in accordance with claim 9 wherein said core comprises from 40% to 100% by weight amide-imide resinous polymer.

Claim 14

A composite engine part in accordance with claim 9 wherein said core comprises from 65% to 75% by weight amide-imide resinous polymer.

Claim 15

A composite engine part in accordance with claim 9 wherein said core comprises a fibrous reinforcing material selected from the group consisting essentially of graphite and glass.

Claim 16

A composite engine part in accordance with claim 14 wherein said core comprises from 10% to 50% by weight graphite.

Claim 17

A composite engine part in accordance with claim 15 wherein said core comprises from 30% to 34% by weight graphite.

Claim 18

A composite engine part in accordance with claim 14 wherein said core comprises 10% to 60% by weight glass.

Claim 19

A composite engine part in accordance with claim 17 wherein said core comprises 30% to 34% by weight glass.

Claim 20

A composite engine part in accordance with claim 14 wherein said fibrous reinforcing material has a polymeric sizing that substantially maintains its structural integrity at engine operating conditions.

Claim 21

A composite engine part in accordance with claim 14 wherein said core comprises not greater than 3% by weight polytetrafluoroethylene.

Claim 22

A composite engine part in accordance with claim 20 wherein said core comprises from 1/2% to 1% by weight polytetrafluoroethylene.

Claim 23

A composite engine part in accordance with claim 14 wherein said core comprises not more than 6% by weight titanium dioxide.

Claim 24

A process for forming and connecting a composite wrist pin, comprising the steps of: molding an amide-imide resinous polymer to form a core; allowing said amide-imide resinous polymeric core to cool below its plastic deformation temperature; post curing said core by solid state polymerization; press fitting said cured core into a metal sleeve; and pivotally connecting a piston to a connecting rod by pivotally fitting said sleeve in the wrist pin holes of said piston and said connecting rod.

Claim 25

A process for forming and connecting a composite wrist pin, comprising the steps of: molding an amide-imide resinous polymer to form a core; allowing said amide-imide resinous polymeric core to cool below its plastic deformation temperature; post curing said core by solid state polymerization; press fitting said cured core into a metal sleeve; and pivotally connecting a piston to a connecting rod by pivotally fitting said sleeve in the wrist pin holes of said piston and said connecting rod.

Claim 26

A process in accordance with claim 23 wherein said molding includes compression molding.

Claim 27

A process in accordance with claim 23 wherein said molding includes injection molding.

Claim 28

A process in accordance with claim 23 wherein a substantially solid core is formed.

Claim 29

A process in accordance with claim 23 wherein an annular core is formed.

Claim 30

A process in accordance with claim 23 wherein said sleeve is formed by cutting and grinding extruded metal tubing.

Claim 31

A process in accordance with claim 23 wherein said metal comprises aluminum.

Claim 32

A process in accordance with claim 23 wherein said metal comprises steel.

Claim 33

A process in accordance with claim 23 wherein said amide-imide polymer is prepared by reacting a trifunctional carboxylic acid compound with at least one diprimary aromatic diamine.

Claim 34

A process in accordance with claim 31 wherein said amide-imide polymer comprises one of the following moieties: ##STR12## wherein one carbonyl group is meta to and one carbonyl group is para to each amide group and wherein Z is a trivalent benzene ring or lower-alkyl-substituted trivalent benzene ring, R 1 and R 2 are different and are divalent aromatic hydrocarbon radicals of from 6 to about 10 carbon atoms or two divalent aromatic hydrocarbon radicals of from 6 to about 10 carbon atoms joined directly or by stable linkages selected from the group consisting of --O--, methylene, --CO--, --SO 2 --, and --S-- radicals and wherein said R 1 and R 2 containing units run from about 10 mole percent R 1 containing unit and about 90 mole percent R 2 containing unit to about 90 mole percent R 1 containing unit and about 10 mole percent R 2 containing unit.

Claim 35

A process in accordance with claim 32 wherein R 1 is ##STR13##

Claim 36

A process in accordance with claim 32 wherein Z is a trivalent benzene ring, R 1 is ##STR14## R 2 is ##STR15## and wherein the concentration range runs from about 30 mole percent of the R 1 containing units and about 70 mole percent of the R 2 containing units to about 70 mole percent of the R 1 containing units and about 30 mole percent of the R 2 containing units.

Claim 37

A process in accordance with claim 32 wherein said polymer comprises from 10% to 50% by weight graphite fibers.

Claim 38

A process in accordance with claim 35 wherein said polymer comprises from 30% to 34% by weight graphite fibers.

Claim 39

A process in accordance with claim 32 wherein said polymer comprises from 10% to 60% by weight glass fibers.

Claim 40

A process in accordance with claim 37 wherein said polymer comprises from 30% to 34% by weight glass fibers.