Manufacture and Use of Parallel Eccentric Electro-Mechanical Actuator

Abstract

A parallel eccentric electro-mechanical actuator provides motive power and includes an electric prime mover that drives the reducer's pinion gear. This pinion drives minimum three star gears with stationary shaft bearings. Each shaft contains an eccentric which are completely in parallel with each other. These eccentrics can be thought of as parallel/in-phase driven crankshafts. Each eccentric drives the parallel eccentric (PE) gear through a bearing. The PE gear exhibits a circular motion (without rotation) which in itself is unbalanced. The crankshafts have another eccentric which create an opposite inertia force to balance that of the PE gear. The PE gear contains an external toothed gear on its periphery. It meshes with the internal teeth of the output ring gear. The relative motion between the PE gear and the ring gear is that the PE gear rolls inside the ring gear. This relative motion is called hypo-cycloidal motion.

1 . A rotary electromechanical actuator, comprising:
 a gear train having first and second meshing gears which engage across a circular arc gear tooth mesh, and wherein the first gear moves in hypocyclic motion with respect to the second gear.   
     
     
         2 . The rotary actuator of  claim 1 , wherein said first gear is a sun gear or planet gear, and wherein said second gear is a sun gear or bull gear. 
     
     
         3 . The actuator of  claim 2 , wherein said first gear is a sun gear, and wherein said sun gear is equipped with circular arc gear teeth. 
     
     
         4 . (canceled) 
     
     
         5 . The rotary actuator of  claim 1 , further comprising:
 a prime mover which drives said gear train;   a bearing; and   a quick-change interface which rotatingly engages said bearing and which is driven by said gear train.   
     
     
         6 . The actuator of  claim 5 , wherein said gear train is a star compound gear train. 
     
     
         7 . The actuator of  claim 5 , wherein said bearing is a cross-roller bearing. 
     
     
         8 . The rotary actuator of  claim 1 , further comprising:
 a shell;   an output attachment plate;   a first mechanical link rigidly attached to said shell;   a second mechanical link rigidly attached to said output attachment plate; and   a bearing disposed adjacent to said first and second mechanical links and in contact with said output plate.   
     
     
         9 . The actuator of  claim 8 , further comprising a prime mover; wherein said joint rigidly resists motion about 5 degrees of freedom, and wherein a sixth degree of freedom is controlled by the prime mover and gear train combination. 
     
     
         10 . (canceled) 
     
     
         11 . The actuator of  claim 8 , wherein said bearing is a cross-roller bearing. 
     
     
         12 . The actuator of  claim 8 , wherein said first mechanical link is attached to said shell by way of a first wedge clamp, and wherein said second mechanical link is attached to said output attachment plate by way of a second wedge clamp. 
     
     
         13 . (canceled) 
     
     
         14 . The actuator of  claim 12 , wherein said first wedge clamp comprises a pair of semi-circular wedge clamp halves tightened against said actuator by way of an external band clamp, and wherein said second wedge clamp comprises a pair of semi-circular wedge clamp halves tightened against said actuator by way of an external band clamp. 
     
     
         15 . (canceled) 
     
     
         16 . The actuator of  claim 8 , further comprising a bull gear in contact with said bearing and said first mechanical link, and a sun gear which meshes with said bull gear; wherein said sun gear has a first plurality of teeth, wherein said bull gear has a second plurality of teeth, and wherein said first plurality of teeth meshes with said second plurality of teeth. 
     
     
         17 . (canceled) 
     
     
         18 . (canceled) 
     
     
         19 . The actuator of  claim 18 , wherein each of said first plurality of teeth includes a cavity. 
     
     
         20 . The rotary actuator of  claim 1 , further comprising:
 a bull gear having a set of internal teeth;   a ring gear having a set of internal teeth; and   a meshing gear having a set of external teeth;   
       wherein the internal gear teeth of the bull gear, the internal teeth of the ring gear, and the external teeth of the meshing gear mesh with a pressure angle of less than about 9 degrees. 
     
     
         21 . The rotary actuator of  claim 1 , further comprising:
 an eccentric, hypocyclic gear train including (a) a bull gear having a set of internal teeth, (b) a ring gear having a set of internal teeth, and (c) a meshing gear having a set of external teeth; wherein the internal gear teeth of the bull gear, the internal teeth of the ring gear, and the external teeth of the meshing gear mesh with a pressure angle of less than about 9 degrees.   
     
     
         22 . The rotary actuator of  claim 1 , further comprising:
 a hypocyclic gear train in which at least 5 gear teeth are in contact at any time when the gear train is under load.   
     
     
         23 . (canceled) 
     
     
         24 . (canceled) 
     
     
         25 . The rotary actuator of  claim 1 , further comprising:
 a gear train which includes a bull gear, a ring gear, and a meshing gear, wherein said bull gear, ring gear and meshing gear have a preloaded force applied thereto.   
     
     
         26 . The rotary actuator of  claim 25 , wherein the bull gear has a set of internal teeth, wherein the ring gear has a set of internal teeth, wherein the meshing gear has a set of external teeth, and wherein the preloading force is derived from interfacing the external gear teeth of the meshing gear, the internal gear teeth of the bull gear and the internal gear teeth of the ring gear in a cusp motion perpendicular to the meshing gear. 
     
     
         27 . The rotary actuator of  claim 25 , wherein the bull gear has a set of internal teeth, wherein the ring gear has a set of internal teeth, wherein the meshing gear has a set of external teeth, and wherein the bull gear, ring gear and meshing gear are interfaced to provide load sharing among the internal teeth of the bull gear, the internal teeth of the ring gear and the external teeth of the meshing gear. 
     
     
         28 . The rotary actuator of  claim 27 , wherein the internal teeth of the bull gear, the internal teeth of the ring gear and the external teeth of the meshing gear interact through concave-convex tooth contact. 
     
     
         29 . The rotary actuator of  claim 28 , wherein the internal teeth of the bull gear, the internal teeth of the ring gear and the external teeth of the meshing gear form a force distribution characteristic in the form of a symmetric parabola. 
     
     
         30 . The rotary actuator of  claim 26 , wherein the meshing gear is a wobble gear. 
     
     
         31 . The rotary actuator of  claim 27 , wherein the meshing gear is a wobble gear. 
     
     
         32 . The rotary actuator of  claim 1 , wherein said gear train is a hypocyclic gear train and operates over the entire range of reduction ratios of 10:1 to 5000:1. 
     
     
         33 . (canceled) 
     
     
         34 . The rotary actuator of  claim 32 , wherein said rotary actuator is a parallel eccentric electromechanical actuator. 
     
     
         35 . The rotary actuator of  claim 32 , wherein the gear train operates over the entire range of reduction ratios of 75:1 to 5000:1. 
     
     
         36 . The rotary actuator of  claim 1 , wherein said gear train is a star compound gear train. 
     
     
         37 . (canceled) 
     
     
         38 . The actuator of  claim 36 , wherein said gear train has at least 5 gear teeth in contact at any time. 
     
     
         39 . The rotary actuator of  claim 1 , further comprising:
 first, second and third star gears;   a reducer equipped with a pinion gear, wherein said pinion gear drives said first, second and third star gears with first, second and third respective stationary shaft bearings, and wherein said first, second and third shaft bearings are arranged in parallel;   a prime mover which drives said pinion gear;   first, second and third eccentrics contained, respectively, in said first, second and third shaft bearings, wherein each of said first, second and third eccentrics have the value e;   a first set of eccentric gears containing first, second and third members which are driven, respectively, by said first, second and third eccentrics through an associated bearing; and   a second set of eccentric gears containing first, second and third members, each of which drives a parallel eccentric balance mass and has an eccentric with magnitude k×e.   
     
     
         40 . The rotary actuator of  claim 1 , further comprising:
 a ring gear; and   a parallel eccentric (PE) gear;   
       wherein said PE gear meshes with said ring gear so as to impart a hypo-cycloidal motion to the PE gear. 
     
     
         41 . The rotary actuator of  claim 40 , wherein said PE gear is disposed inside of said ring gear. 
     
     
         42 . The rotary actuator of  claim 41 , wherein said ring gear is equipped with a first plurality of inward facing teeth, and wherein said PE gear is equipped with a second plurality of outward facing teeth which rotatingly engage said first plurality of teeth. 
     
     
         43 . (canceled) 
     
     
         44 . The rotary actuator of  claim 40 , wherein said actuator is a parallel eccentric electromechanical actuator. 
     
     
         45 . (canceled) 
     
     
         46 . The rotary actuator of  claim 40 , wherein said actuator further comprises:
 a gear reducer equipped with a pinion gear; and   a prime mover that drives the pinion gear.   
     
     
         47 . The rotary actuator of  claim 46 , wherein said gear reducer provides gear reduction over the entire reduction range of 25:1 to 75:1. 
     
     
         48 . The rotary actuator of  claim 46 , wherein said pinion drives a plurality of star gears. 
     
     
         49 . (canceled) 
     
     
         50 . (canceled)