Turbocharger wheel balance-test jig

1. A turbocharger wheel balance-test jig, comprising:

a base defining an axis of rotation, the base having a base clamping face forming at least a portion of a base conical feature that is normal to and rotationally symmetric around the axis of rotation;

a clamp mechanism rigidly connected to the base; and

an arm extending along the axis of rotation from the clamp mechanism toward the base clamping face, the arm having an arm clamping face forming at least a portion of an arm conical feature that is normal to and rotationally symmetric around the axis of rotation;

wherein the base conical feature and the arm conical feature face one another;

wherein the clamp mechanism includes an actuator that is actuatable between a locked position and an unlocked position, the locked position rigidly holding the arm with respect to the base, and the unlocked position providing for the arm to be axially moved along the axis of rotation; and

wherein the clamp mechanism includes a stop configured to restrict rotation of the arm around the axis of rotation in both the unlocked and the locked positions.

2. The turbocharger wheel balance-test jig of claim 1 , wherein:

the clamp mechanism actuator includes a locking nut that is threadedly received on a collet; and

the stop is further configured to restrict rotation of the collet around the axis of rotation in both the unlocked and the locked positions.

3. The turbocharger wheel balance-test jig of claim 2 , wherein:

the clamp mechanism includes a hollow cylindrical clamp housing;

the collet is concentrically received within the clamp housing;

the arm is concentrically received within the collet;

the stop is a pin that is affixed to and extends across the clamp housing; and

the pin passes through axially extending holes in the collet and an axially extending hole in the arm.

4. A method for acceptance testing an imbalance level of a turbocharger wheel, the turbocharger wheel including a hub having a back face and a nose cone, comprising:

mounting the turbocharger wheel balance-test jig of claim 1 in a dynamic balancing machine;

measuring an imbalance level of the of the turbocharger wheel balance-test jig using the dynamic balancing machine;

zeroing all subsequent measured results based on this mounting of the test jig;

measuring an imbalance level of the turbocharger wheel, using the dynamic balancing machine, a plurality of times, each time with the turbocharger wheel being separately installed in the turbocharger wheel balance-test jig, to establish a plurality of imbalance levels of the turbocharger wheel;

forming an estimated indicator of turbocharger wheel imbalance based upon a combination of the plurality of the imbalance levels of the turbocharger wheel balance-test jig and the turbocharger wheel; and

accepting or rejecting the turbocharger wheel based upon the estimated indicator of the turbocharger wheel imbalance.

5. The method for acceptance testing an imbalance level of a turbocharger wheel of claim 4 , wherein the step of measuring an imbalance level of the of the turbocharger wheel balance-test jig includes the steps of:

actuating the clamp mechanism actuator of the turbocharger wheel balance-test jig into its locked position if it is not already in that position;

running the dynamic balancing machine; and

taking an Imbalance measurement to establish an imbalance level of the turbocharger wheel balance-test jig.

6. The method for acceptance testing an imbalance level of a turbocharger wheel of claim 4 , wherein the step of measuring an imbalance level of the turbocharger wheel of includes the steps of:

(a) actuating the turbocharger wheel balance-test jig actuator into the unlocked position if it is not already in that position;

(b) raising the balance-test jig arm if it is not already in that position;

(c) centering the back face of the turbocharger wheel on the base clamping face;

(d) lowering the turbocharger wheel balance-test jig arm to position the arm clamping face against the turbocharger wheel nose cone such that the balance-test jig arm is centered on the turbocharger wheel nose cone;

(e) actuating the turbocharger wheel balance-test jig actuator from the unlocked position to the locked position such that the turbocharger wheel is rigidly locked into the turbocharger wheel balance-test jig;

(f) running the dynamic balancing machine;

(g) taking an Imbalance measurement to establish an imbalance level of the turbocharger wheel;

(h) repeating steps (a) through (g) to establish a plurality of imbalance levels of the turbocharger wheel.

7. The method for acceptance testing an imbalance level of a turbocharger wheel of claim 6 , wherein:

on the first time steps (a) through (g) are conducted, the step of measuring an imbalance level of the turbocharger wheel balance-test jig and the turbocharger wheel of further includes the step of marking the turbocharger wheel with a mark such that the rotational orientation with respect to the base is established; and

on subsequent times steps (a) through (g) are conducted, the step of measuring an imbalance level of the turbocharger wheel balance-test jig and the turbocharger wheel further includes the step of positioning the turbocharger wheel using the mark such that the rotational orientation of the turbocharger wheel with respect to the base is the same as the first time steps (a) through (g) were conducted.

8. The method for acceptance testing an imbalance level of a turbocharger wheel of claim 4 , wherein the step of zeroing comprises conducting a Zero Reset on the dynamic balancing machine after the step of measuring an imbalance level of the of the turbocharger wheel balance-test jig, and after the step of measuring an imbalance level of the turbocharger wheel.

9. The method for acceptance testing an imbalance level of a turbocharger wheel of claim 4 , wherein the step of zeroing is conducted prior to the step of measuring an imbalance level of the turbocharger wheel.