Sheet metal piston for transmissions and method of making a piston assembly

Claim 2

A piston assembly for selectively engaging a friction drive establishing device comprising an annular thin wall shell having inner and outer rims, an annular channel formed in the face of said shell bounded by a cylindrical wall disposed adjacent to said outer rim, contact means for a friction drive establishing device operatively disposed in said channel, said contact means comprising a thin wall metallic member with free end portions and curved into a circular member, said contact means being resiliently constrictable into a smaller circular configuration for installation into said channel and being provided with radially extending projections thereon which contact said cylindrical wall to yieldably retain said contact member in said shell, and said contact means having surface means on one face thereof for engagement with a friction drive establishing device.

Claim 3

A piston assembly for a friction device of a change speed gear unit comprising a thin wall annular shell having inner and outer rims, said sHell having annular seal means for hydraulically sealing said piston assembly for movement in a piston bore, said shell further having an annular channel located between said rims with offset and arcuately spaced spring pockets formed in the bottom wall of said channel, an annular spring guide disposed in said channel, said spring guide having arcuately spaced projections which extend into said spring pockets to limit turning movement of said spring guide relative to said shell, each of said projections having axially extending opening means therein, return spring means for said piston assembly seated in said spring pockets and extending through said opening means of said projections, and contact means carried by said shell for directly engaging a friction device of the change speed gear unit.

Claim 4

A piston assembly for a friction device of a change speed gear unit comprising a thin wall annular shell having inner and outer rims, said sHell having annular seal means for hydraulically sealing said piston assembly for movement in a piston bore, said shell further having an annular channel located between said rims with offset and arcuately spaced spring pockets formed in the bottom wall of said channel, an annular spring guide disposed in said channel, said spring guide having arcuately spaced projections which extend into said spring pockets to limit turning movement of said spring guide relative to said shell, each of said projections having axially extending opening means therein, return spring means for said piston assembly seated in said spring pockets and extending through said opening means of said projections, and contact means carried by said shell for directly engaging a friction device of the change speed gear unit.

Claim 5

A piston assembly for selectively engaging a friction drive establishing device comprising an annular thin wall shell of sheet metal of substantially uniform thickness having radially extending inner and outer rims, said shell having a longitudinally extending cylindrical wall adjacent to said outer rim and inwardly offset therefrom, an annular channel formed in the face of said shell bounded by said cylindrical wall, contact means for a friction drive establishing device operatively disposed in said channel and projecting axially from the face of said shell, said contact means comprising a thin wall metallic member of substantially uniform width having free end portions, said contact means being curved into a circular spring member so that said free end portions are adjacent to each other, said contact means being resiliently constrictable into a smaller circular configuration by a constricting force for insertion into said channel, said contact means having a peripheral portion including radially extending projections thereon which engage said cylindrical wall subsequent to insertion into said channel and removal of said constricting force, and said contact means having surface means on one face thereof for engagement with a friction drive establishing device.

Claim 6

A piston assembly for selectively engaging a friction drive establishing device comprising an annular thin wall shell of sheet metal of substantially uniform thickness having radially extending inner and outer rims, said shell having a longitudinally extending cylindrical wall adjacent to said outer rim and inwardly offset therefrom, an annular channel formed in the face of said shell bounded by said cylindrical wall, contact means for a friction drive establishing device operatively disposed in said channel and projecting axially from the face of said shell, said contact means comprising a thin wall metallic member of substantially uniform width having free end portions, said contact means being curved into a circular spring member so that said free end portions are adjacent to each other, said contact means being resiliently constrictable into a smaller circular configuration by a constricting force for insertion into said channel, said contact means having a peripheral portion including radially extending projections thereon which engage said cylindrical wall subsequent to insertion into said channel and removal of said constricting force, and said contact means having surface means on one face thereof for engagement with a friction drive establishing device.

Claim 7

A piston assembly for selectively engaging a friction drive establishing device comprising an annular thin-walled piston shell of sheet metal stock having a substantially uniform thickness and having an inner annular opening, said piston shell having radially extending inner and outer rims to respectively form the inner and outer diameters of said piston shell, said piston shell having an annular depression formed in the inner face thereof, said shell having a cylindrical wall extending axially from the outer circumference of said annular depression, axially extending contact means for a friction drive establishing device mounted in said annular depression projecting axially from said shell beyond said cylindrical wall, said contact means comprising a curved thin wall metallic spring member of substantially uniform width and thickness, said spring member having free end portions facing each other, said spring member being constrictable from a relaxed state for insertion into said annular depression and having side portions including radially extending projections thereon urged into engagement with said cylindrical wall by the force of restitution of said spring member, and elastomeric lip seal means extending radially beyond said inner and outer rims for fluid sealing engagement with a housing for said piston assembly.

Claim 8

A piston assembly for selectively engaging a friction drive establishing device comprising an annular thin-walled piston shell of sheet metal stock having a substantially uniform thickness and having an inner annular opening, said piston shell having radially extending inner and outer rims to respectively form the inner and outer diameters of said piston shell, said piston shell having an annular depression formed in the inner face thereof, said shell having a cylindrical wall extending axially from the outer circumference of said annular depression, axially extending contact means for a friction drive establishing device mounted in said annular depression projecting axially from said shell beyond said cylindrical wall, said contact means comprising a curved thin wall metallic spring member of substantially uniform width and thickness, said spring member having free end portions facing each other, said spring member being constrictable from a relaxed state for insertion into said annular depression and having side portions including radially extending projections thereon urged into engagement with said cylindrical wall by the force of restitution of said spring member, and elastomeric lip seal means extending radially beyond said inner and outer rims for fluid sealing engagement with a housing for said piston assembly.

Claim 9

A piston assembly for selectively engaging a friction drive establishing device comprising an annular thin-walled piston shell of sheet metal stock having a substantially uniform thickness and having an inner annular opening, said piston shell having radially extending inner and outer rims to respectively form the inner and outer diameters of said piston shell, said piston shell having an annular depression formed in the inner face thereof, said shell having a cylindrical wall extending axially from the outer circumference of said annular depression, axially extending contact means mounted in saId shell for direct engagement with a friction drive establishing device, said contact means being mounted in said annular depression projecting axially from said shell, said contact means comprising a curved thin wall metallic spring member of substantially uniform width and thickness, said spring member having free end portions, said spring member being constrictable from a relaxed state for insertion into said annular depression and having radially extending side portions including radially extending projections thereon urged into engagement with said cylindrical wall by the force of restitution of said spring member, annular elastomeric lip seal means extending radially beyond said inner and outer rims for fluid sealing engagement with a housing for said piston assembly, annular seal retainer means for each of said lip seal means, each of said seal retainer means being a thin-walled metallic ring of uniform thickness and being L-shaped in cross section, each of said rings having a longitudinally extending wall mounted on the outer face of said piston shell and a radially extending wall spaced from the outer face of said piston shell to form inner and outer grooves for said inner and outer lip seals.

Claim 10

A piston assembly for selectively engaging a friction drive establishing device comprising an annular thin-walled piston shell of sheet metal stock having a substantially uniform thickness and having an inner annular opening, said piston shell having radially extending inner and outer rims to respectively form the inner and outer diameters of said piston shell, said piston shell having an annular depression formed in the inner face thereof, said shell having a cylindrical wall extending axially from the outer circumference of said annular depression, axially extending contact means mounted in saId shell for direct engagement with a friction drive establishing device, said contact means being mounted in said annular depression projecting axially from said shell, said contact means comprising a curved thin wall metallic spring member of substantially uniform width and thickness, said spring member having free end portions, said spring member being constrictable from a relaxed state for insertion into said annular depression and having radially extending side portions including radially extending projections thereon urged into engagement with said cylindrical wall by the force of restitution of said spring member, annular elastomeric lip seal means extending radially beyond said inner and outer rims for fluid sealing engagement with a housing for said piston assembly, annular seal retainer means for each of said lip seal means, each of said seal retainer means being a thin-walled metallic ring of uniform thickness and being L-shaped in cross section, each of said rings having a longitudinally extending wall mounted on the outer face of said piston shell and a radially extending wall spaced from the outer face of said piston shell to form inner and outer grooves for said inner and outer lip seals.

Claim 11

A piston assembly for a friction device of a change speed gear unit comprising a thin wall annular sheet metal shell of substantially uniform thickness having inner and outer peripheral rims, said outer rim having a cylindrical portion contact means extending axially in a first direction for contacting a friction device, said shell having annular elastomeric seal means for hydraulically sealing said piston assembly for movement in a piston bore, said shell further having an annular channel located between said rims, said shell having arcuately spaced spring pockets formed in the bottom wall of said channel and projecting axially therefrom in a direction opposite to said first direction, an annular spring guide disposed in said channel, said spring guide having arcuately spaced projections which fit into said spring pockets to limit turning movement of said spring guide relative to said shell, each of said projections having axially extending opening means therein, and return spring means for said piston assembly seated in said spring pockets and extending through said opening means of said projections.

Claim 12

A piston assembly for a friction device of a change speed gear unit comprising a thin wall annular sheet metal shell of substantially uniform thickness having inner and outer peripheral rims, said outer rim having a cylindrical portion contact means extending axially in a first direction for contacting a friction device, said shell having annular elastomeric seal means for hydraulically sealing said piston assembly for movement in a piston bore, said shell further having an annular channel located between said rims, said shell having arcuately spaced spring pockets formed in the bottom wall of said channel and projecting axially therefrom in a direction opposite to said first direction, an annular spring guide disposed in said channel, said spring guide having arcuately spaced projections which fit into said spring pockets to limit turning movement of said spring guide relative to said shell, each of said projections having axially extending opening means therein, and return spring means for said piston assembly seated in said spring pockets and extending through said opening means of said projections.

Claim 13

A piston assembly for a friction device of a change speed gear unit comprising an annular shell of sheet metal having a substantially uniform thickness, said shell having an outer annular axially extending rim for engaging a friction device and a radially extending inner annular rim defining a central opening in said shell, said shell having an annular channel depressed in the inside face thereof, said shell having inner and outer annular shoulders on the outer face thereof, annular lip seal retainer means mounted on said inner and outer annular shoulders, each of said retainer means being of uniform thickness and L-shaped in cross section, each of said retainer means having an axially extending leg fitted on the associated annular shoulder and a radially extending leg spaced from said shell to form inner and outer lip seal retainer grooves, annular inner and outer lip seals respectively mounted in said inner and outer lip seal grooves, said shell having arcuately spaced spring pockets formed in the bottom wall of said channel and projecting axially therefrom, a ring-like spring guide having internal and external diameters mounted in said channel, said spring guide having arcuately spaced projections which extend into said spring pockets to limit turning movement of said spring guide relative to said shell, each of said projections having axially extending opening means therein, return spring means for said piston assembly seated in said spring pockets and extending through said opening means of said projections.

Claim 14

A piston assembly for a friction device of a change speed gear unit comprising an annular shell of sheet metal having a substantially uniform thickness, said shell having an outer annular axially extending rim for engaging a friction device and a radially extending inner annular rim defining a central opening in said shell, said shell having an annular channel depressed in the inside face thereof, said shell having inner and outer annular shoulders on the outer face thereof, annular lip seal retainer means mounted on said inner and outer annular shoulders, each of said retainer means being of uniform thickness and L-shaped in cross section, each of said retainer means having an axially extending leg fitted on the associated annular shoulder and a radially extending leg spaced from said shell to form inner and outer lip seal retainer grooves, annular inner and outer lip seals respectively mounted in said inner and outer lip seal grooves, said shell having arcuately spaced spring pockets formed in the bottom wall of said channel and projecting axially therefrom, a ring-like spring guide having internal and external diameters mounted in said channel, said spring guide having arcuately spaced projections which extend into said spring pockets to limit turning movement of said spring guide relative to said shell, each of said projections having axially extending opening means therein, return spring means for said piston assembly seated in said spring pockets and extending through said opening means of said projections.