Electric camshaft phaser assembly including a flexible gear with a retainer

Patent metadata

Field	Value
Publication number	US-12454898-B2
Application number	US-202418629350-A
Country	US
Kind code	B2
Filing date	Apr 8, 2024
Priority date	Apr 8, 2024
Publication date	Oct 28, 2025
Grant date	Oct 28, 2025

Abstract

A camshaft phaser assembly configured for phasing a camshaft and a crankshaft with respect to each other is provided. The camshaft phaser assembly includes a sprocket for receiving torque from the crankshaft; an output gear for driving the camshaft; a flexible gear deformable into an elliptical orientation for engaging the output gear to transmit torque from the sprocket to the output gear; and a wave generator for deforming the flexible gear into the elliptical orientation; the flexible gear radially disposed about the wave generator and including an inner circumferential surface in contact with an outer race of the wave generator, the flexible gear including teeth for engaging the output gear in the elliptical orientation and a retainer at an axial end of the flexible gear, the output gear including a centering feature configured for contacting the retainer to center the flexible gear in the elliptical orientation inside of the output gear.

First claim

What is claimed is:

1 . A camshaft phaser assembly configured for phasing a camshaft and a crankshaft with respect to each other, the camshaft phaser assembly comprising:
a sprocket for receiving torque from the crankshaft; an output gear configured for driving the camshaft; a flexible gear deformable into an elliptical orientation for engaging the output gear to transmit torque from the sprocket to the output gear; and a wave generator for deforming the flexible gear into the elliptical orientation; the flexible gear radially disposed about the wave generator and including an inner circumferential surface in contact with an outer race of the wave generator, the flexible gear including teeth for engaging the output gear in the elliptical orientation and a retainer at an axial end of the flexible gear, the output gear including a centering feature configured for contacting the retainer to center the flexible gear in the elliptical orientation inside of the output gear.

2 . The camshaft phaser assembly as recited in claim 1 , wherein the flexible gear includes a cylindrical section including the teeth and the retainer.

3 . The camshaft phaser assembly as recited in claim 2 , wherein the retainer forms a rim of a first end of the cylindrical section.

4 . The camshaft phaser assembly as recited in claim 2 , wherein the flexible gear further includes a disc section at a second end of the cylindrical section extending radially away from the cylindrical section.

5 . The camshaft phaser assembly as recited in claim 1 , wherein the centering feature is defined by walls of a groove formed in the output gear.

6 . The camshaft phaser assembly as recited in claim 5 , wherein the groove is defined by an axially extending inner circumferential surface, an axially extending outer circumferential surface and a radially extending surface extending from the inner circumferential surface to the outer circumferential surface.

7 . The camshaft phaser assembly as recited in claim 6 , wherein an axial edge of the retainer directly faces the radially extending surface of the groove.

8 . The camshaft phaser assembly as recited in claim 6 , wherein the flexible gear is configured such that, in the elliptical orientation, two portions of the outer circumferential surface of the retainer contact the outer circumferential surface of the groove and two portions of the inner circumferential surface of the retainer contact the inner circumferential surface of the groove.

9 . The camshaft phaser assembly as recited in claim 6 , wherein the inner circumferential surface and the outer circumferential surface taper radially away from each other while extending axially away from the radially extending surface.

10 . The camshaft phaser assembly as recited in claim 1 , wherein the output gear includes a cylindrical section including a plurality of teeth on an inner circumferential surface thereof, some of the teeth of the output gear engaging some of the teeth of the flexible gear in the elliptical orientation.

11 . The camshaft phaser assembly as recited in claim 10 , wherein the output gear includes a disc section extending radially inward from the cylindrical section, the centering feature being on the disc section.

12 . The camshaft phaser assembly as recited in claim 11 , wherein the centering feature is a groove formed in a radially outer extent of the disc section.

13 . The camshaft phaser assembly as recited in claim 1 , wherein the retainer is ring-shaped.

14 . A method of constructing a camshaft phaser assembly configured for phasing a camshaft and a crankshaft with respect to each other, the method comprising:
coupling an output gear to a sprocket; installing a flexible gear inside of the output gear with teeth of the flexible gear received inside of teeth of the output gear; and installing a wave generator inside of the output gear, the flexible gear being deformable by the wave generator into an elliptical orientation in which some of the teeth of the flexible gear engage some of the teeth of the output gear to transmit torque from the sprocket to the output gear, the flexible gear including a retainer extending axially away from the teeth, the installing of the flexible gear inside of the output gear including inserting a retainer defining a first axial end of the flexible gear into a centering feature of the output gear to center the flexible gear inside of the output gear in the elliptical orientation.

15 . The method as recited in claim 14 wherein the coupling of the output gear to the sprocket includes inserting the output gear inside of the sprocket, the output gear configured for being connected to the camshaft.

16 . The method as recited in claim 14 further comprising non-rotatably connecting the flexible gear to the sprocket.

17 . The method as recited in claim 16 wherein the flexible gear includes a cylindrical section including the teeth and the retainer, and a disc section at a second axial end of the cylindrical section extending radially away from the cylindrical section,
the non-rotatably connecting of the flexible gear to the output gear including fastening the disc section to the sprocket.

18 . The method as recited in claim 14 wherein the centering feature is a groove formed in a radially extending surface of the output gear, the groove being defined by an axially extending inner circumferential surface, an axially extending outer circumferential surface and a radially extending surface extending from the inner circumferential surface to the outer circumferential surface,
the inserting of the retainer into the centering feature including moving the retainer toward the radially extending surface defining the groove.

19 . The method as recited in claim 14 , wherein the flexible gear includes a cylindrical section including the teeth and the retainer, and a disc section at a second end of the cylindrical section extending radially away from the cylindrical section,
wherein the output gear includes a cylindrical section including the teeth on an inner circumferential surface thereof, and a disc section extending radially inward from the cylindrical section, the centering feature being on the disc section, the installing of the flexible gear inside of the output gear including installing the cylindrical section of the flexible gear inside of the cylindrical section of the output gear.

20 . The method as recited in claim 19 , wherein the centering feature is a groove formed in a radially outer extent of the disc section.

Assignees

• Schaeffler Technologies Ag

Inventors

• Foster Colin
• Burke Steven

Classifications

• F16H2049/003

  Features of the flexsplines therefor · CPC title

• F01L2303/00

  Manufacturing of components used in valve arrangements · CPC title

• F16H49/001

  Wave gearings, e.g. harmonic drive transmissions · CPC title

• F01L2001/3521

  Harmonic drive of flexspline type · CPC title

• F01L1/344 Primary

  changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear · CPC title