Methods for making a low inertia laminated rotor

Abstract

A rotor assembly having a plurality of rotor plates mounted to a shaft, and methods of construction for a rotor assembly are disclosed. Each rotor plate in the assembly may be provided with a central opening extending between the first and second sides through which the shaft extends. In one aspect, the rotor plates are provided with a plurality of lobes extending away from the central opening, wherein each of the lobes has a lobe opening extending through the thickness of the plates. In one embodiment, the rotor plates are rotationally stacked to form a helical rotor.

What is claimed is: 
     
         1 . A method of making a laminated rotor, the method comprising the steps of:
 a. providing a plurality of rotor plates, each of the plates having a plurality of lobes extending radially away from a central opening and a first indexing feature;   b. providing a mandrel having a second indexing feature;   c. stacking each of the rotor plates onto the mandrel such that the mandrel extends through the central opening of each plate and such that the rotor plate first indexing feature is aligned with the mandrel second indexing feature;   d. securing the rotor plates together;   e. removing the mandrel from the rotor plates; and   f. inserting a shaft into the central openings of the rotor plates.   
     
     
         2 . The method of making a laminated rotor of  claim 1 , wherein the step of providing a plurality of rotor plates includes providing at least some of the rotor plates with openings in the rotor plate lobes. 
     
     
         3 . The method of making a laminated rotor of  claim 1 , wherein the step of securing the rotor plates together includes welding the rotor plates together. 
     
     
         4 . The method of making a laminated rotor of  claim 1 , further including the step of burring the shaft before the step of inserting the shaft into the central openings of the rotor plates. 
     
     
         5 . The method of making a laminated rotor of  claim 1 , wherein the step of inserting a shaft is performed after the step of securing the rotor plates together. 
     
     
         6 . The method of making a laminated rotor of  claim 1  further including the step of forming each of the plurality rotor plates by one of stamping, fine blanking, laser cutting, and water jet cutting. 
     
     
         7 . The method of making a laminated rotor of  claim 1 , wherein the step of providing a mandrel includes providing a mandrel with the second indexing feature having a plurality of protrusions extending along a length of the mandrel. 
     
     
         8 . The method of making a laminated rotor of  claim 7 , wherein the step of providing a mandrel includes providing a mandrel with the second indexing feature having a plurality of helical protrusions. 
     
     
         9 . The method of making a laminated rotor of  claim 8 , wherein the step of providing a mandrel includes providing a mandrel with the second indexing feature having three helical protrusions. 
     
     
         10 . The method of making a laminated rotor of  claim 8 , wherein the step of providing a plurality of rotor plates includes providing a plurality of rotor plates having a plurality of recesses forming the first indexing feature. 
     
     
         11 . The method of making a laminated rotor of  claim 10 , wherein the steps of providing a mandrel and providing a plurality of rotor plates includes providing a mandrel with a number of protrusions that is equal to a number of recesses provided on each rotor plate. 
     
     
         12 . A rotor assembly comprising:
 a. a plurality of rotor plates, each including:
 i. a first side and a second opposite side separated by a first thickness; 
 ii. a central opening extending between the first and second sides; 
 iii. a plurality of lobes extending away from the central opening; 
 iv. an indexing feature including at least one recess extending from the central opening; and 
   b. a shaft extending through the central opening of each of the plurality of rotor plates;   c. wherein the plurality of rotor plates are stacked and secured together to form the rotor assembly such that at least one of the first and second sides of one rotor plate is adjacent to and in contact with at least one of the first and second sides of another rotor plate.   
     
     
         13 . The rotor assembly of  claim 12 , wherein the rotor plates are rotated with respect to each other to form a helical rotor. 
     
     
         14 . The rotor assembly of  claim 13 , wherein each of the plurality of rotor plates includes first, second, and third lobes that are radially spaced apart by an equal angular degree. 
     
     
         15 . The rotor assembly of  claim 14 , wherein each of the plurality of rotor plates further includes a fourth lobe, wherein the first, second, third, and fourth lobes are radially spaced apart by an equal angular degree. 
     
     
         16 . The rotor assembly of  claim 13 , wherein the helical rotor has an overall length that is generally equal to the sum of the first thicknesses of the plurality of stacked rotor plates. 
     
     
         17 . The rotor assembly of  claim 12 , wherein each of the plurality of lobes includes a lobe opening. 
     
     
         18 . The rotor assembly of  claim 12 , wherein each of the rotor plates is formed from a metal material. 
     
     
         19 . The rotor assembly of  claim 18 , wherein each of the rotor plates is formed from stainless steel. 
     
     
         20 . The rotor assembly of  claim 18 , wherein the rotor plates are secured together by welding.