Noncircular gear pair

Patent metadata

Field	Value
Publication number	US-12287028-B2
Application number	US-202218048563-A
Country	US
Kind code	B2
Filing date	Oct 21, 2022
Priority date	Oct 22, 2021
Publication date	Apr 29, 2025
Grant date	Apr 29, 2025

Abstract

The present disclosure describes innovations to improve the use of noncircular gear pairs in a transmission, e.g., an infinitely variable transmission. The noncircular gear pair includes a first noncircular gear with a first pitch curve; and a second noncircular gear with a second pitch curve. The first pitch curve includes a plurality of elliptical portions, and a curvature of the first pitch curve is positive along the entire first pitch curve; and wherein the second pitch curve is a conjugate of the first pitch curve.

First claim

What is claimed is:

1. A noncircular gear comprising:
a pitch curve having
a first elliptical portion relating to a first ellipse;
a second elliptical portion relating to a second ellipse, different than the first ellipse; and
a modified transition portion positioned between the first elliptical portion and the second elliptical portion; and
wherein the pitch curve includes no cusps; and
wherein an eccentricity of each of the first elliptical portion and the second elliptical portion is within a range of 0.1 to 0.9.

2. The noncircular gear of claim 1 , wherein the modified transition portion is a first modified transition portion and the pitch curve further comprises a third elliptical portion relating to a third ellipse, different than the first ellipse and the second ellipse, and a second modified transition portion positioned between the second elliptical portion and the third elliptical portion.

3. The noncircular gear of claim 2 , wherein the pitch curve further comprises a fourth elliptical portion relating to a fourth ellipse.

4. The noncircular gear of claim 3 , wherein the pitch curve further comprises a fifth elliptical portion relating to a fifth ellipse and a sixth elliptical portion relating to a sixth ellipse.

5. The noncircular gear of claim 1 , wherein the eccentricity of each of the first elliptical portion and the second elliptical portion is within a range of 0.1 to 0.3.

6. The noncircular gear of claim 5 , wherein the eccentricity of each of the first elliptical portion and the second elliptical portion is 0.15.

7. The noncircular gear of claim 1 , wherein a curvature of the pitch curve is positive along the entire pitch curve.

8. The noncircular gear of claim 1 , wherein the noncircular gear is manufacturable with a shaping cutter with a constant radius.

9. The noncircular gear of claim 1 , further including a plurality of teeth.

10. A method of manufacturing a non-circular gear pair, the method comprising:
calculating kinematic equations of the non-circular gear pair;
generating a non-circular pitch curve including a plurality of lobes based on the kinematic equations;
modifying the non-circular pitch curve to remove cusps to create a modified pitch curve; wherein the modified pitch curve includes a first elliptical portion relating to a first ellipse, a second elliptical portion relating to a second ellipse, different than the first ellipse, and a modified transition portion positioned between the first elliptical portion and the second elliptical portion;
generating a tooth profile based on the modified pitch curve; and
cutting the tooth profile with a shaping cutter having a constant radius.

11. The noncircular gear of claim 1 , wherein the first elliptical portion is the same shape as the second elliptical portion.

12. The noncircular gear of claim 3 , wherein the first elliptical portion, the second elliptical portion, the third elliptical portion, and the fourth elliptical portion are the same shape.

Assignees

• Univ Maryland

Inventors

• Zhu Weidong
• Li Gang

Classifications

• F16H2035/003

  Gearings comprising pulleys or toothed members of non-circular shape, e.g. elliptical gears · CPC title

• F16H35/02 Primary

  for conveying rotary motion with cyclically varying velocity ratio · CPC title