Gears with varying pressure angle

Patent metadata

Field	Value
Publication number	US-10634231-B2
Application number	US-201615132761-A
Country	US
Kind code	B2
Filing date	Apr 19, 2016
Priority date	Apr 19, 2016
Publication date	Apr 28, 2020
Grant date	Apr 28, 2020

Abstract

Gears are known to have a whine that can be unpleasant to operators or occupants of vehicles. A gear set is disclosed in which the pressure angle of the teeth varies along the periphery of the gear. A mating gear also has teeth with varying pressure angle. The teeth that mate have an identical pressure angle so that present disclosure is applicable only to 1:1 or integer ratio gears: 2:1, 3:1, etc. Because the teeth meet differently as a function of the pressure angle, the fundamental vibration frequency is not reinforced as would be the case with all teeth having the same pressure angle.

First claim

We claim:

1. A gear set, comprising:
a first gear having a first portion of teeth having a first pressure angle and a second portion of teeth having a second pressure angle;
a second gear having a first portion of teeth having the first pressure angle and a second portion of teeth having the second pressure angle;
a third portion of teeth on the first gear having a third pressure angle; and
a third portion of teeth on the second gear having the third pressure angle,

wherein the first portion of the first gear teeth mesh with the first portion of the second gear teeth during operation; the first pressure angle does not equal the second pressure angle; the first portion of teeth of the first gear are dissimilar from the second portion of teeth of the first gear; the first portion of teeth of the second gear are dissimilar from the second portion of teeth of the second gear; the first pressure angle does not equal the third pressure angle; and the second pressure angle does not equal the third pressure angle.

2. The gear set of claim 1 wherein:
total number of teeth on the first gear equals total number of teeth on the second gear;
a number of teeth in the first portion of teeth of the first gear is one greater than number of teeth in the first portion of the second gear; and
the second gear has a transition tooth in which the pressure angle on a first side of the tooth is the first pressure angle and the pressure angle on a second side of the tooth is the second pressure angle.

3. The gear set of claim 1 wherein:
total number of teeth on the first gear divided by total number of teeth on the second gear yields a quotient of one of: two, three, four, five, one-half, one-third, one-quarter, and one-fifth;
number of teeth in the first portion of the first gear equals the quotient times the number of teeth of the second gear;
when the quotient is greater than one, the first portion of teeth on the first gear is separated into evenly-spaced regions with the number of regions equal to the quotient; and
when the quotient is less than one, the first portion of teeth on the second gear is separated into evenly-spaced regions with the number of regions equal to the reciprocal of the quotient.

4. The gear set of claim 3 wherein:
when the quotient is greater than one, the first portion of teeth on the second gear are mutually adjacent; and
when the quotient is less than one, the first portion of teeth on the first gear are mutually adjacent.

5. The gear set of claim 1 , further comprising:
a first shaft;
a second shaft arranged in parallel with the first shaft;
a first index on the first gear; and
a second index on the second gear wherein:
the first gear is mounted on the first shaft;
the second gear is mounted on the second shaft; and
the first and second index are lined up when the driving and second gears are enmeshed.

6. The gear set of claim 1 wherein the teeth of the first gear are evenly spaced on a periphery of the first gear; and the teeth of the second gear are evenly space on a periphery of the second gear.

7. The gear set of claim 1 wherein:
the first portion of teeth of the first gear is mutually exclusive from the second portion of teeth of the first gear.

8. The gear set of claim 1 wherein:
the first portion of teeth in the first gear is located in a first sector of the first gear;
the second portion of teeth in the first gear is located in a second sector of the second gear; and
the first and second sectors are identical in size.

9. A gear set, comprising:
a first gear in which teeth in a first sector have a first pressure angle and teeth in a second sector have a second pressure angle; and
a second gear in which teeth in a third sector have the first pressure angle and teeth in a fourth sector have the second pressure angle wherein the first and second gears are enmeshed; a tooth in the first sector adjacent to a tooth in the second sector are different.

10. The gear set of claim 9 wherein:
the first gear further comprises a fifth sector in which the teeth have a third pressure angle;
the second gear further comprise a sixth sector in which the teeth have the third pressure angle;
the first pressure angle is different from the second and third pressure angles; and
the second pressure angle is different from the third pressure angle.

11. The gear set of claim 10 wherein the teeth of the first gear and the second gear that sit on an overlap between the two sectors are transition teeth in which the pressure angle on one side of the tooth differs from the pressure angle on the other side of the tooth.

12. The gear set of claim 9 wherein:
a number of whole teeth in the first sector of the first gear is within one of a number of whole teeth in the third sector of the second gear.

13. The gear set of claim 9 wherein:
the second gear further comprises a fifth sector in which the teeth have the first pressure angle;
the second gear further comprises a sixth sector in which the teeth have the second pressure angle;
the fifth sector is located between the third and fourth sectors; and
when the gears rotate, the teeth of the first sector mesh with the teeth of the third and fifth sectors; and the teeth of the second sector mesh with the teeth of the fourth and sixth sectors.

14. The gear set of claim 9 , further comprising:
a first shaft;
a second shaft arranged in parallel with the first shaft wherein:
the first shaft is inserted into a centrally-defined opening on the first gear; and
the second shaft is inserted into a centrally-defined opening on the second gear.

15. The gear set of claim 14 wherein:
the first shaft, the second shaft, the centrally-defined opening on the first gear, and the centrally-defined opening on the second gear each have a keyway defined therein, the gear set further comprising:
a first key inserted into the keyways of the first shaft and the keyway on the first gear; and
a second key inserted into the keyways of the second shaft the keyway on the second gear.

16. The gear set of claim 9 wherein:
teeth of the first gear are evenly spaced on the periphery of the first gear; and
teeth of the second gear are evenly spaced on the periphery of the second gear.

17. The gear set of claim 9 wherein:
teeth of the first portion of teeth of the first gear are substantially identical;
teeth of the second portion of teeth of the first gear are substantially identical; and
teeth of the first portion of teeth of the first gear and teeth of the second portion of teeth of the second gear are different.

18. The gear set of claim 9 wherein:
the first gear is indexed to the second gear; and
a first tooth of the first gear always meshes with a first tooth of the second gear during rotation of the first and second gears.

Assignees

• Ford Global Tech Llc

Inventors

• Moetakef Mohammad Ali
• Zouani Abdelkrim

Classifications

• F16H55/16 Primary

  relating to teeth only · CPC title

• F16H1/06

  with parallel axes · CPC title

• F16H55/17 Primary

  Toothed wheels (worm wheels F16H55/22; chain wheels F16H55/30) · CPC title

• F16H2055/086

  Silent gear profiles · CPC title

• F16H55/08

  Profiling · CPC title