Rocker arm and process for producing the same

Claim 2

A rocker arm made from a carbon-fiber reinforced resin wherein the central axis of a rocker shaft hole through which the rocker shaft is inserted is referenced as Z-axis, a line parallel to a surface of a valve side of the rocker arm opposite a surface having a cam contact face and which crosses the Z-axis at point 0 at a right angle, is referenced as a Y-axis, the line that is parallel to the surface of the cam side of the rocker arm opposite the surface having the cam contact face and which crosses the Z-axis at point 0 at a right angle is referenced as a Y'-axis, and the bisector of the angle YOY' is referenced as a X-axis, and wherein cos 2 β, the average of cos 2 β of the carbon fibers present on the Y-axis side with respeact to a X-Z plane and carbon fibers present on the Y'-axis side with respect to X-Z plane, is not more than 0.9924, β being the angle of orientation with respect to the Y-axis of a first group of fibers as the fibers are projected onto the X-Y plane and the angle of orientation with respect to the Y'-axis of the second group of fibers as they are projected onto the X-Y' plane, and cos 2 α, the average of cos 2 α of the first group of fibers and second group of fibers is not less than 3/4, α being the angle of orientation with respect to the Y-axis of the first group of fibers as they are projected onto Z-Y plane and the angle of orientation with respect to the Y'-axis of the second group of fibers as they are projected onto Z-Y' plane.

Claim 3

A rocker arm according to claim 1 wherein cos 2 β is from 0.9924 to 0.25.

Claim 4

A rocker arm according to claim 1 wherein cos 2 α is from 1 to 0.9930.

Claim 5

A rocker arm according to claim 1 wherein two carbon fiber projected lines in X-Y and X-Y' planes intersect each other at an angle of not of less than an average of 5 degrees.

Claim 6

A rocker arm according to claim 1 wherein the carbon fibers are 5 to 100 mm long.

Claim 7

A rocker arm according to claim 1 wherein the carbon fibers are 10 to 50 mm long.

Claim 8

A rocker arm according to claim 1 wherein the length of the carbon fibers is from 1/1 to 1/10 of the maximum length of the rocker arm in the direction along the Y- and Y'-axis.

Claim 9

A rocker arm according to claim 1 wherein the carbon fibers are chopped fibers.

Claim 10

A rocker arm according to claim 1 wherein the carbon fibers are in the form of fabrics, felt of braiding.

Claim 11

A rocker arm according to claim 1 wherein the carbon fibers have a diameter of from 1 to 20μ.

Claim 12

A rocker arm according to claim 1 wherein the carbon fibers have a tensile strength of more than 150 kg/mm 2 .

Claim 13

A rocker arm according to claim 1 wherein the carbon fibers have a tensile modulus of more than 15,000 kg/mm 2 .

Claim 14

A rocker arm according to claim 1 wherein the resin used in the carbon-fiber reinforced resin is a heat-cured thermosetting resin.

Claim 15

A rocker arm according to claim 13 wherein the thermosetting resin is selected from the group consisting of epoxy resins, polyimide resins, phenolic resins and polyester resins.

Claim 16

A rocker arm according to claim 1 wherein the resin used in the carbon-fiber reinforced resin is a thermoplastic resin.

Claim 17

A rocker arm according to claim 15 wherein the thermoplastic resin is a polysulfone resin.

Claim 18

A rocker arm according to claim 1 wherein the carbon-fiber reinforced synthetic resin is filled with 30 to 80% by volume of the carbon fibers.

Claim 19

A rocker arm according to claim 8, wherein the carbon fibers placed in the X-Y and X-Y' planes are in a random orientation.

Claim 20

A rocker arm according to claim 9, wherein fabrics are laminated in a direction perpendicular to the Z-axis.

Claim 21

A rocker arm according to claim 1, wherein the rocker arm has a metal insert element inserted in the cam contact face, the adjusting screw mounting area or the circumference of the rocker shaft hole.

Claim 22

A process for producing a rocker arm made of carbon-fiber reinforced synthetic resin, comprising packing a rocker arm mold with carbon fibers and a synthetic resin in such a manner that cos 2 β, the average cos 2 β of the carbon fibers present on the Y-axis side with respect X-Z plane and carbon fibers present on the Y'-axis side with respect X-Z plane, is not more than 0.9924, β being the angle of orientation with respect to the Y-axis of the first group of fibers as they are projected onto a X-Y plane and the angle of orientation with respect to the Y'-axis of the second group of fibers as they are projected onto the X-Y' plane, and heating and pressing the packed material in the direction of a Z-axis in such a manner that cos 2 α, the average of cos 2 α of the first group of fibers and second group of fibers is not less than 3/4, α being the angle of orientation with respect to the Y-axis of the first group of fibers as projected onto a Z-Y plane and the angle of orientation with respect to the Y'-axis of the second group of fibers as they are projected onto a Z-Y' plane, Z-axis being the central axis of the hole through which the rocker shaft is inserted. Y-axis being the line that is parallel to a surface of a valve side of the rocker arm opposite a surface having a cam contact face and which crosses the Z-axis at a point 0 at a right angle, Y'-axis being a line parallel to a surface of a cam side on a surface of the rocker arm opposite the surface having the cam contact face and which crosses the Z-axis at the point 0 at a right angle, and an X-axis being the bisector of the angle YOY'.

Claim 23

A process for producing a rocker arm made of carbon-fiber reinforced synthetic resin, comprising packing a rocker arm mold with carbon fibers and a synthetic resin in such a manner that cos 2 β, the average cos 2 β of the carbon fibers present on the Y-axis side with respect X-Z plane and carbon fibers present on the Y'-axis side with respect X-Z plane, is not more than 0.9924, β being the angle of orientation with respect to the Y-axis of the first group of fibers as they are projected onto a X-Y plane and the angle of orientation with respect to the Y'-axis of the second group of fibers as they are projected onto the X-Y' plane, and heating and pressing the packed material in the direction of a Z-axis in such a manner that cos 2 α, the average of cos 2 α of the first group of fibers and second group of fibers is not less than 3/4, α being the angle of orientation with respect to the Y-axis of the first group of fibers as projected onto a Z-Y plane and the angle of orientation with respect to the Y'-axis of the second group of fibers as they are projected onto a Z-Y' plane, Z-axis being the central axis of the hole through which the rocker shaft is inserted. Y-axis being the line that is parallel to a surface of a valve side of the rocker arm opposite a surface having a cam contact face and which crosses the Z-axis at a point 0 at a right angle, Y'-axis being a line parallel to a surface of a cam side on a surface of the rocker arm opposite the surface having the cam contact face and which crosses the Z-axis at the point 0 at a right angle, and an X-axis being the bisector of the angle YOY'.

Claim 24

A process for producing a rocker arm according to claim 21, wherein a metal insert element is provided to the rocker arm simultaneously with the molding of the rocker arm.