Composite valve and process

Claim 2

A composite engine valve, comprising: a metal valve head for opening and closing an engine manifold communicating with a cylinder of an engine; and an elongated, thermoplastic, amide-imide resinous polymeric valve stem connected to said valve head said thermoplastic amide-imide valve stem and said metal valve head maintaining their structural integrity at engine operating conditions.

Claim 3

A composite engine valve in accordance with claim 1 wherein said valve head and said valve stem each define connection parts and one of said connection parts has a threaded stud extending outwardly therefrom and the other connection part has stud-receiving means for threadedly receiving said stud.

Claim 4

A composite engine valve in accordance with claim 2 wherein said stud-receiving means is an internally threaded hole.

Claim 5

A composite engine valve in accordance with claim 2 wherein said stud-receiving means includes a recess and a coil spring positioned within said recess for threadedly engaging said stud.

Claim 6

A composite engine valve in accordance with claim 4 wherein said valve head has said stud, and said valve stem has said coil spring and defines said recess.

Claim 7

A composite engine valve in accordance with claim 1 wherein said valve head defines a stem head-receiving cavity, and said valve stem has an enlarged insert molded stem head shaped generally complementary to and positioned within said cavity.

Claim 8

A composite engine valve in accordance with claim 1 wherein said valve head has a generally planar, circular disc, and said sidewalls have a general semi-hyperboloid shape.

Claim 9

A composite engine valve in accordance with claim 1 wherein said valve head and stem are substantially solid.

Claim 10

A composite engine valve in accordance with claim 1 wherein said metal is selected from the group consisting of aluminum and steel.

Claim 11

A composite engine valve in accordance with claim 1 wherein said amide-imide stem defines at least one keeper-receiving groove for receiving split keeper rings or locking keys which wedge against and connect a valve spring retainer to said amide-imide stem.

Claim 12

A composite engine valve in accordance with claim 1 wherein said metal comprises titanium.

Claim 13

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

Claim 14

A composite engine part in accordance with claim 12 wherein said valve stem comprises at least one of the following moieties: ##STR10## 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 15

A composite engine part in accordance with claim 13 wherein R 1 is ##STR11##

Claim 16

A composite engine part in accordance with claim 13 wherein Z is a trivalent benzene ring, R 1 is ##STR12## R 2 is ##STR13## 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 17

A composite engine part in accordance with claim 13 wherein said valve stem comprises from 40% to 100% by weight amide-imide resinous polymer.

Claim 18

A composite engine part in accordance with claim 16 wherein said valve stem comprises from 65% to 75% by weight amide-imide resinous polymer.

Claim 19

A composite engine part in accordance with claim 13 wherein said valve stem comprises a fibrous reinforcing material selected from the group consisting essentially of graphite and glass.

Claim 20

A composite engine part in accordance with claim 18 wherein said valve stem comprises from 10% to 50% by weight graphite.

Claim 21

A composite engine part in accordance with claim 19 wherein said valve stem comprises from 30% to 34% by weight graphite.

Claim 22

A composite engine part in accordance with claim 18 wherein said valve stem comprises 10% to 60% by weight glass.

Claim 23

A composite engine part in accordance with claim 21 wherein said valve stem comprises 30% to 34% by weight glass.

Claim 24

A composite engine part in accordance with claim 18 wherein said fibrous reinforcing material has a polymeric sizing that substantially maintains its structural integrity at engine operating conditions.

Claim 25

A composite engine part in accordance with claim 18 wherein said valve stem comprises not greater than 3% by weight polytetrafluoroethylene.

Claim 26

A composite engine part in accordance with claim 24 wherein said valve stem comprises from 1/2% to 1% by weight polytetrafluoroethylene.

Claim 27

A composite engine part in accordance with claim 18 wherein said valve stem comprises not more than 6% by weight titanium dioxide.

Claim 28

A process for forming a composite valve for use in an engine, comprising the steps of: molding a thermoplastic, amide-imide resinous polymer to form an elongated valve stem; allowing said amide-imide valve stem to cool below its plastic deformation temperature; post curing said amide-imide valve stem by solid state polymerization to enhance the strength and integrity of said amide-imide valve stem; forming a metal valve head; and connecting said amide-imide valve stem to said metal valve head.

Claim 29

A process for forming a composite valve for use in an engine, comprising the steps of: molding a thermoplastic, amide-imide resinous polymer to form an elongated valve stem; allowing said amide-imide valve stem to cool below its plastic deformation temperature; post curing said amide-imide valve stem by solid state polymerization to enhance the strength and integrity of said amide-imide valve stem; forming a metal valve head; and connecting said amide-imide valve stem to said metal valve head.

Claim 30

A process in accordance with claim 27 including cutting at least one keeper-receiving groove on said stem with a lathe.

Claim 31

A process in accordance with claim 27 wherein said valve head is formed at least in part on a screw machine.

Claim 32

A process in accordance with claim 29 including threading said valve head; drilling a recess in said stem; and placing a coil spring in said recess; and wherein said connecting includes screwing the threaded portion of said valve head into said coil spring.

Claim 33

A process in accordance with claim 27 including grinding said head and said stem.

Claim 34

A process in accordance with claim 27 wherein said molding comprises injection molding.

Claim 35

A process in accordance with claim 27 wherein said valve head is formed with a cavity prior to said molding; and said molding and said connecting are performed together by insert molding said valve stem into said cavity of said head.

Claim 36

A process in accordance with claim 27 wherein said valve head is formed on a lathe.

Claim 37

A process in accordance with claim 27 wherein said metal valve head is selected from the group consisting of aluminum, steel and titanium.

Claim 38

A process in accordance with claim 27 wherein said amide-imide polymer is prepared by reacting a trifunctional carboxylic acid compound with at least one diprimary aromatic diamine.

Claim 39

A process in accordance with claim 36 wherein said amide-imide polymer comprises one of the following moieties: ##STR14## 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 40

A process in accordance with claim 37 wherein R 1 is ##STR15##

Claim 41

A process in accordance with claim 37 wherein Z is a trivalent benzene ring, R 1 is ##STR16## R 2 is ##STR17## 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 42

A process in accordance with claim 37 wherein said polymer comprises from 10% to 50% by weight graphite fibers.

Claim 43

A process in accordance with claim 40 wherein said polymer comprises from 30% to 34% by weight graphite fibers.

Claim 44

A process in accordance with claim 37 wherein said polymer comprises from 10% to 60% by weight glass fibers.

Claim 45

A process in accordance with claim 42 wherein said polymer comprises from 30% to 34% by weight glass fibers.

Claim 46

A process in accordance with claim 36 wherein said polymer comprises a fibrous reinforcing material selected from the group consisting essentially of graphite and glass; and said fibrous reinforcing material is axially injected into a stem-shaped cavity of a mold and oriented in an axial direction in said cooled valve stem.