Necked impeller shell for torque converter

1. An impeller for a torque converter comprising:

an axis of rotation;

an impeller shell comprising:

a torus portion;

a radial wall portion;

an elbow portion;

an interior portion;

an inner peripheral surface;

an outer peripheral surface;

a first thickness between the inner peripheral surface and the outer peripheral surface;

a plurality of blades attached to the inner peripheral surface; and,

an axially extending necked portion connected to the radial wall portion, extending about the axis of rotation and into the interior portion, having:

a first circumferential surface;

a second circumferential surface; and

a second thickness between the first circumferential surface and the second circumferential surface, wherein the second thickness is less than the first thickness of the impeller shell;

an impeller hub attached to the outer peripheral surface of the radial wall portion of the impeller shell via a weld, wherein the weld is disposed in a region where the radial wall portion meets the torus portion of the impeller shell; and

a bearing disposed inside the interior portion of the impeller shell and arranged on the first circumferential surface of the axially extending necked portion, wherein the bearing is radially aligned with the impeller hub.

2. The impeller as in claim 1 , wherein the elbow portion connects the axially extending necked portion to the radial wall portion at an angle of about 90 degrees.

3. A torque converter comprising:

an axis of rotation;

a turbine;

an impeller comprising an impeller shell having:

a torus portion;

a radial wall portion;

an interior portion;

an inner peripheral surface;

an outer peripheral surface;

a first thickness between the inner peripheral surface and the outer peripheral surface;

a plurality of blades attached to the inner peripheral surface;

an axially extending necked portion about the axis of rotation, extending into the interior portion, having:

a first circumferential surface;

a second circumferential surface; and,

a second thickness between the first circumferential surface and the second circumferential surface, wherein the second thickness is less than the first thickness of the impeller shell;

an elbow portion connecting the radial wall portion and the necked portion;

an impeller hub attached to the outer peripheral surface of the radial wall portion of the impeller shell via a weld, wherein the weld is disposed in a region where the radial wall portion meets the torus portion of the impeller shell;

a bearing disposed inside the interior portion of the impeller shell and arranged on the first circumferential surface of the axially extending necked portion, wherein the bearing is radially aligned with the impeller hub; and,

a stator,

wherein a space is axially bound by the second circumferential surface.

4. The torque converter as in claim 3 , wherein the torque converter is arranged for installation between an engine and a transmission, and wherein the axially extending necked portion extends in a direction toward the engine.

5. The torque converter as in claim 3 , wherein the space is arranged for receiving a stator shaft and a transmission input shaft.

6. The torque converter as in claim 3 , wherein the necked portion is at an angle of about 90 degrees relative to the radial wall portion.

7. The torque converter as in claim 3 wherein the weld includes a radially outward toe for reduced rotary bend stresses between the toe of the weld and the impeller shell.

8. A torque converter comprising:

an axis of rotation;

a turbine;

an impeller comprising an impeller shell having:

a plurality of blades attached to an inner peripheral surface thereof;

a radial wall;

a torus portion;

an inner peripheral surface;

an outer peripheral surface;

a first thickness between the inner peripheral surface and the outer peripheral surface;

an axially extending neck about the axis of rotation extending into an interior portion, the axially extending neck comprising first and second circumferential surfaces, the second circumferential surface defining an opening arranged for receiving a stator shaft and a transmission input shaft, wherein the axially extending neck includes a second thickness between the first circumferential surface and the second circumferential surface that is less than the first thickness of the impeller shell; and,

an elbow portion connecting the radial wall and the axially extending neck at an angle of about 90 degrees;

a stator;

an impeller hub attached to the outer peripheral surface of the radial wall of the impeller shell via a weld, wherein the weld is disposed in a region where the radial wall meets the torus portion of the impeller shell; and

a bearing disposed inside the interior portion of the impeller shell and arranged on the first circumferential surface of the axially extending neck extending into the interior portion, wherein the bearing is radially aligned with the impeller hub.

9. The torque converter as in claim 8 , wherein the torque converter is arranged for installation between an engine and a transmission, and wherein the bearing is disposed axially between the radial wall and the engine.

10. The torque converter as in claim 8 , wherein the bearing comprises at least one of the following: a roller bearing; a thrust bearing; a fluid film thrust bearing and a slide bearing.

11. The torque converter as in claim 10 , wherein the bearing is a thrust bearing comprising a first hardened backing washer, a cage including rollers, and a second backing washer.

12. The torque converter as in claim 8 wherein the impeller hub is tubular or forged.