Internal gear and manufacturing method thereof with die

Patent metadata

Field	Value
Publication number	US-2016245388-A1
Application number	US-201514969409-A
Country	US
Kind code	A1
Filing date	Dec 15, 2015
Priority date	Feb 20, 2015
Publication date	Aug 25, 2016
Grant date	—

Abstract

An internal gear includes plural teeth each including an addendum area, a dedendum area, and an intermediate area including a protrusion and a recessed portion. The intermediate area includes a first border position provided at a position between the protrusion and the recessed portion, a second border position provided at a position between the intermediate area and the dedendum area, a third border position provided at a position between the intermediate area and the addendum area, a first average radius provided from the first border position to the second border position, and a second average radius provided from the first border position to the third border position. The first average radius is smaller than the second average radius. The addendum area includes a first curvature radius provided at a first center position in a tooth thickness direction, the first curvature radius being set at a maximum.

First claim

1 . An internal gear, comprising:
a plurality of teeth configuring the internal gear; the plurality of teeth each including
an addendum area when seen from an extending direction of a rotary axis of the internal gear;
a dedendum area when seen from the extending direction of the rotary axis of the internal gear; and
an intermediate area when seen from the extending direction of the rotary axis of the internal gear, the intermediate area being continuously formed between the addendum area and the dedendum area, the intermediate area including a protrusion and a recessed portion, the protrusion protruding toward each of teeth surfaces of the teeth being positioned next to one another, the recessed portion being recessed so as to be away from each of the teeth surfaces being positioned next to one another, the intermediate area being continuously formed with the protrusion and the recessed portion to be formed in a trochoid curve; wherein
the intermediate area includes:
a first border position being provided at a position between the protrusion and the recessed portion;
a second border position being provided at a position between the intermediate area and the dedendum area;
a third border position being provided at a position between the intermediate area and the addendum area;
a first average radius serving as an average curvature radius of an area from the first border position to the second border position; and
a second average radius serving as an average curvature radius of an area from the first border position to the third border position;
the first average radius is smaller than the second average radius by comparison; and the addendum area includes a first curvature radius being provided at a first center position in a tooth thickness direction, the first curvature radius being set at a maximum.

2 . The internal gear according to claim 1 ; wherein the first border position has a pressure angle that is set to be zero.

3 . The internal gear according to claim 1 , wherein
the dedendum area includes a first dimension along a tooth depth direction; the intermediate area includes a second dimension along the tooth depth direction; the addendum area includes a third dimension along the tooth depth direction; and each of the first dimension and the third dimension is set to be 5 to 10 percent of the second dimension.

4 . The internal gear according to claim 1 , wherein the addendum area includes a second curvature radius that is set smaller towards the first border position from the first center position.

5 . The internal gear according to claim 1 , wherein
the dedendum area includes a third curvature radius being provided at a second center position in the tooth thickness direction; and the first curvature radius is set greater than the third curvature radius (R 4 ).

6 . A die for the form rolling process comprising:
a plurality of teeth configuring the internal gear; the plurality of teeth each including
an addendum area when seen from an extending direction of a rotary axis of the internal gear;
a dedendum area when seen from the extending direction of the rotary axis of the internal gear; and
an intermediate area when seen from the extending direction of the rotary axis of the internal gear, the intermediate area being continuously formed between the addendum area and the dedendum area, the intermediate area including a protrusion and a recessed portion, the protrusion protruding toward each of teeth surfaces of the teeth being positioned next to one another, the recessed portion being recessed so as to be away from each of the teeth surfaces being positioned next to one another, the intermediate area being continuously formed with the protrusion and the recessed portion to be formed in a trochoid curve; wherein
the intermediate area includes:
a first border position being provided at a position between the protrusion and the recessed portion;
a second border position being provided at a position between the intermediate area and the dedendum area;
a third border position being provided at a position between the intermediate area and the addendum area;
a first average radius serving as an average curvature radius of an area from the first border position to the second border position; and
a second average radius serving as an average curvature radius of an area from the first border position to the third border position;
the first average radius is greater than the second average radius by comparison; the dedendum area includes a first curvature radius being provided at a first center position in a tooth thickness direction; the addendum area includes a second curvature radius being provided at a second center position in the tooth thickness direction; and the first curvature radius is set smaller than the second curvature radius.

7 . The die for the form rolling process according to claim 6 , wherein
the dedendum area includes a first dimension along a tooth depth direction; the intermediate area includes a second dimension along the tooth depth direction; the addendum area includes a third dimension along the tooth depth direction; and each of the first dimension and the third dimension is set to be 5 to 10 percent of the second dimension.

8 . The die for the form rolling process according to claim 6 , wherein the addendum area includes a highest position that is dislocated to one of a first side and a second side relative to the second center position of the addendum area.

9 . A manufacturing method of an internal gear, the manufacturing method having a form rolling process being performed with a die for the form rolling process; the die comprising:
a plurality of teeth, the plurality of teeth configuring the die, the plurality of teeth each including
an addendum area when seen from an extending direction of a rotary axis of the die;
a dedendum area when seen from the extending direction of the rotary axis of the die;
an intermediate area when seen from the extending direction of the rotary axis of the die, the intermediate area including a protrusion and a recessed portion, the intermediate area being continuously formed between the addendum area and the dedendum area, the protrusion protruding toward each of teeth surfaces of the teeth, the teeth surfaces being positioned next to one another, the recessed portion being recessed so as to be away from each of the teeth surfaces, the teeth surfaces being positioned next to one another, the intermediate area being continuously formed with the protrusion and the recessed portion to be formed in a trochoid curve; wherein
the intermediate area includes:
a first border position being provided at a position between the protrusion and the recessed portion;
a second border position being provided at a position between the intermediate area and the dedendum area;
a third border position being provided at a position between the intermediate area and the addendum area;
a first average radius serving as an average curvature radius of an area from the first border position to the second border position; and
a second average radius serving as an average curvature radius of an area from the first border position to the third border position;
the first average radius is greater than the second average radius by comparison; the dedendum area includes a first curvature radius being provided at a first center position in a tooth thickness direction; the addendum area includes a second curvature radius being provided at a second center position in the tooth thickness direction; and the first curvature radius is set smaller than the second curvature radius.

10 . The manufacturing method of an internal ge

Assignees

• Aisin Seiki

Inventors

• Nagata Eiri

Classifications

• B23F15/00

  Methods or machines for making gear wheels of special kinds not covered by groups B23F7/00 - B23F13/00 · CPC title

• F16H55/08 Primary

  Profiling · CPC title

• F16H2055/176

  Ring gears with inner teeth · CPC title

• B21H5/025

  Internally geared wheels · CPC title

• F16H2055/0866

  Profiles for improving radial engagement of gears, e.g. chamfers on the tips of the teeth · CPC title